text:
Final results of the Resonance spacecraft calibration effort
Sampl, Manfred; Macher, Wolfgang; Gruber, Christian; Oswald, Thomas; Rucker, Helmut O.
antenna properties significantly. The antenna directions and lengths, represented by the "effective length vector" are altered by up to 4 degree in direction and 50% in length, for the quasi-static range. High frequency analyses (up to 40 MHz) illustrate massive antenna pattern changes beyond the quasi-static frequency limit of approximately 1.5 MHz. In addition we found that the magnetic loop sensors tremendously increase the effective lengths and capacitances, depending on their placement on the booms. The antenna calibration results and loop placement findings are of great benefit to the Resonance mission. In particular, goniopolarimetry techniques like polarization analysis and direction finding depend crucially on the effective axes.
A Review on Microdialysis Calibration Methods: the Theory and Current Related Efforts.
Kho, Chun Min; Enche Ab Rahim, Siti Kartini; Ahmad, Zainal Arifin; Abdullah, Norazharuddin Shah
Microdialysis is a sampling technique first introduced in the late 1950s. Although this technique was originally designed to study endogenous compounds in animal brain, it is later modified to be used in other organs. Additionally, microdialysis is not only able to collect unbound concentration of compounds from tissue sites; this technique can also be used to deliver exogenous compounds to a designated area. Due to its versatility, microdialysis technique is widely employed in a number of areas, including biomedical research. However, for most in vivo studies, the concentration of substance obtained directly from the microdialysis technique does not accurately describe the concentration of the substance on-site. In order to relate the results collected from microdialysis to the actual in vivo condition, a calibration method is required. To date, various microdialysis calibration methods have been reported, with each method being capable to provide valuable insights of the technique itself and its applications. This paper aims to provide a critical review on various calibration methods used in microdialysis applications, inclusive of a detailed description of the microdialysis technique itself to start with. It is expected that this article shall review in detail, the various calibration methods employed, present examples of work related to each calibration method including clinical efforts, plus the advantages and disadvantages of each of the methods.
Calibration Efforts and Unique Capabilities of the HST Space Telescope Imaging Spectrograph
Monroe, TalaWanda R.; Proffitt, Charles R.; Welty, Daniel; Branton, Doug; Carlberg, Joleen K.; debes, John Henry; Lockwood, Sean; Riley, Allyssa; Sohn, Sangmo Tony; Sonnentrucker, Paule G.; Walborn, Nolan R.; Jedrzejewski, Robert I.
The Space Telescope Imaging Spectrograph (STIS) continues to offer the astronomy community the ability to carry out innovative UV and optical spectroscopic and imaging studies, two decades after its deployment on the Hubble Space Telescope (HST). Most notably, STIS provides spectroscopy in the FUV and NUV, including high spectral resolution echelle modes, imaging in the FUV, optical spectroscopy, and coronagraphic capabilities. Additionally, spatial scanning on the CCD with the long-slits is now possible to enable very high S/N spectroscopic observations without saturation while mitigating telluric and fringing concerns in the far red and near-IR. This new mode may especially benefit the diffuse interstellar bands and exoplanet transiting communities. We present recent calibration efforts for the instrument, including work to optimize the calibration of the echelle spectroscopic modes by improving the flux agreement of overlapping spectral orders affected by changes in the grating blaze function since HST Servicing Mission 4. We also discuss considerations to maintain the wavelength precision of the spectroscopic modes, and the current capabilities of CCD spectroscopic spatial trails.
International Nuclear Information System (INIS)
Greacen, E.L.; Correll, R.L.; Cunningham, R.B.; Johns, G.G.; Nicolls, K.D.
Procedures common to different methods of calibration of neutron moisture meters are outlined and laboratory and field calibration methods compared. Gross errors which arise from faulty calibration techniques are described. The count rate can be affected by the dry bulk density of the soil, the volumetric content of constitutional hydrogen and other chemical components of the soil and soil solution. Calibration is further complicated by the fact that the neutron meter responds more strongly to the soil properties close to the detector and source. The differences in slope of calibration curves for different soils can be as much as 40%
Calibration of a measurement device as a result of efforts of interaction flow and turbo machines impeller; Calibracao de um dispositivo de medida de esforcos resultantes da interacao entre o escoamento e o rotor de turbomaquinas
Energy Technology Data Exchange (ETDEWEB)
Brandao, Jose Geraldo Trani; Tomazini, Jose Elias [UNESP, Guaratingueta, SP (Brazil). Faculdade de Engenharia. Dept. de Mecanica]. E-mails: email@example.com; firstname.lastname@example.com
This work reports the static calibration of a device used for measurements of the hydraulic efforts resulting from the interaction between the flow and the turbomachinery rotor, simulating the various operation conditions. The device was developed by the Stuttgart University. A calibration process is described for allowing a real correspondence among real efforts acting on the rotor model and the the measured efforts. The used device consists of load three dimension piezoelectric sensors.
Individual dosimetry and calibration
International Nuclear Information System (INIS)
Otto, T.
In 1996, the Dosimetry and Calibration Section was, as in previous years, mainly engaged in routine tasks: the distribution of over 6000 dosimeters (with a total of more than 10,000 films) every two months and the calibration of about 900 fixed and mobile instruments used in the radiation survey sections of RP group. These tasks were, thanks to an experienced team, well mastered. Special efforts had to be made in a number of areas to modernize the service or to keep it in line with new prescriptions. The Individual Dosimetry Service had to assure that CERN's contracting firms comply with the prescriptions in the Radiation Safety Manual (1996) that had been inspired by the Swiss Ordinance of 1994: Companies must file for authorizations with the Swiss Federal Office for Public Health requiring that in every company an 'Expert in Radiation Protection' be nominated and subsequently trained. CERN's Individual Dosimetry Service is accredited by the Swiss Federal Authorities and works closely together with other, similar services on a rigorous quality assurance programme. Within this framework, CERN was mandated to organize this year the annual Swiss 'Intercomparison of Dosimeters'. All ten accredited dosimetry services - among others those of the Paul Scherrer Institute (PSI) in Villigen and of the four Swiss nuclear power stations - sent dosimeters to CERN, where they were irradiated in CERN's calibration facility with precise photon doses. After return to their origin they were processed and evaluated. The results were communicated to CERN and were compared with the originally given doses. A report on the results was subsequently prepared and submitted to the Swiss 'Group of Experts on Personal Dosimetry'. Reference monitors for photon and neutron radiation were brought to standard laboratories to assure the traceability of CERN's calibration service to the fundamental quantities. For photon radiation, a set of ionization chambers was calibrated in the reference field
Hadano, K; Nakamura, H; Hamanaka, T
We report three cases of effortful echolalia in patients with cerebral infarction. The clinical picture of speech disturbance is associated with Type 1 Transcortical Motor Aphasia (TCMA, Goldstein, 1915). The patients always spoke nonfluently with loss of speech initiative, dysarthria, dysprosody, agrammatism, and increased effort and were unable to repeat sentences longer than those containing four or six words. In conversation, they first repeated a few words spoken to them, and then produced self initiated speech. The initial repetition as well as the subsequent self initiated speech, which were realized equally laboriously, can be regarded as mitigated echolalia (Pick, 1924). They were always aware of their own echolalia and tried to control it without effect. These cases demonstrate that neither the ability to repeat nor fluent speech are always necessary for echolalia. The possibility that a lesion in the left medial frontal lobe, including the supplementary motor area, plays an important role in effortful echolalia is discussed.
DEFF Research Database (Denmark)
Heydorn, Kaj; Anglov, Thomas
Methods recommended by the International Standardization Organisation and Eurachem are not satisfactory for the correct estimation of calibration uncertainty. A novel approach is introduced and tested on actual calibration data for the determination of Pb by ICP-AES. The improved calibration...
Unit-specific calibration of Actigraph accelerometers in a mechanical setup - is it worth the effort? The effect on random output variation caused by technical inter-instrument variability in the laboratory and in the field
DEFF Research Database (Denmark)
Moeller, Niels C; Korsholm, Lars; Kristensen, Peter L
BACKGROUND: Potentially, unit-specific in-vitro calibration of accelerometers could increase field data quality and study power. However, reduced inter-unit variability would only be important if random instrument variability contributes considerably to the total variation in field data. Therefor...
Calibration factor or calibration coefficient?
International Nuclear Information System (INIS)
Meghzifene, A.; Shortt, K.R.
Full text: The IAEA/WHO network of SSDLs was set up in order to establish links between SSDL members and the international measurement system. At the end of 2001, there were 73 network members in 63 Member States. The SSDL network members provide calibration services to end-users at the national or regional level. The results of the calibrations are summarized in a document called calibration report or calibration certificate. The IAEA has been using the term calibration certificate and will continue using the same terminology. The most important information in a calibration certificate is a list of calibration factors and their related uncertainties that apply to the calibrated instrument for the well-defined irradiation and ambient conditions. The IAEA has recently decided to change the term calibration factor to calibration coefficient, to be fully in line with ISO [ISO 31-0], which recommends the use of the term coefficient when it links two quantities A and B (equation 1) that have different dimensions. The term factor should only be used for k when it is used to link the terms A and B that have the same dimensions A=k.B. However, in a typical calibration, an ion chamber is calibrated in terms of a physical quantity such as air kerma, dose to water, ambient dose equivalent, etc. If the chamber is calibrated together with its electrometer, then the calibration refers to the physical quantity to be measured per electrometer unit reading. In this case, the terms referred have different dimensions. The adoption by the Agency of the term coefficient to express the results of calibrations is consistent with the 'International vocabulary of basic and general terms in metrology' prepared jointly by the BIPM, IEC, ISO, OIML and other organizations. The BIPM has changed from factor to coefficient. The authors believe that this is more than just a matter of semantics and recommend that the SSDL network members adopt this change in terminology. (author)
Technical guidelines for personnel dosimetry calibrations
International Nuclear Information System (INIS)
Roberson, P.L.; Fox, R.A.; Hadley, R.T.; Holbrook, K.L.; Hooker, C.D.; McDonald, J.C.
A base of technical information has been acquire and used to evaluate the calibration, design, and performance of selected personnel systems in use at Department of Energy (DOE) facilites. A technical document was prepared to guide DOE and DOE contractors in selecting and evaluating personnel dosimetry systems and calibration. A parallel effort was initiated to intercompare the adiological calibrations standards used to calibrate DOE personnel dosimeters
Directory of Open Access Journals (Sweden)
Pozhitkov Alexander E
Full Text Available Abstract Background Calibration of a microarray scanner is critical for accurate interpretation of microarray results. Shi et al. (BMC Bioinformatics, 2005, 6, Art. No. S11 Suppl. 2. reported usage of a Full Moon BioSystems slide for calibration. Inspired by the Shi et al. work, we have calibrated microarray scanners in our previous research. We were puzzled however, that most of the signal intensities from a biological sample fell below the sensitivity threshold level determined by the calibration slide. This conundrum led us to re-investigate the quality of calibration provided by the Full Moon BioSystems slide as well as the accuracy of the analysis performed by Shi et al. Methods Signal intensities were recorded on three different microarray scanners at various photomultiplier gain levels using the same calibration slide from Full Moon BioSystems. Data analysis was conducted on raw signal intensities without normalization or transformation of any kind. Weighted least-squares method was used to fit the data. Results We found that initial analysis performed by Shi et al. did not take into account autofluorescence of the Full Moon BioSystems slide, which led to a grossly distorted microarray scanner response. Our analysis revealed that a power-law function, which is explicitly accounting for the slide autofluorescence, perfectly described a relationship between signal intensities and fluorophore quantities. Conclusions Microarray scanners respond in a much less distorted fashion than was reported by Shi et al. Full Moon BioSystems calibration slides are inadequate for performing calibration. We recommend against using these slides.
International Nuclear Information System (INIS)
Mack, D.A.
Procedures for the calibration of different types of laboratory equipment are described. Provisions for maintaining the integrity of reference and working standards traceable back to a national standard are discussed. Methods of validation and certification methods are included. An appendix lists available publications and services of national standardizing agencies
Vibration transducer calibration techniques
Brinkley, D. J.
Techniques for the calibration of vibration transducers used in the Aeronautical Quality Assurance Directorate of the British Ministry of Defence are presented. Following a review of the types of measurements necessary in the calibration of vibration transducers, the performance requirements of vibration transducers, which can be used to measure acceleration, velocity or vibration amplitude, are discussed, with particular attention given to the piezoelectric accelerometer. Techniques for the accurate measurement of sinusoidal vibration amplitude in reference-grade transducers are then considered, including the use of a position sensitive photocell and the use of a Michelson laser interferometer. Means of comparing the output of working-grade accelerometers with that of previously calibrated reference-grade devices are then outlined, with attention given to a method employing a capacitance bridge technique and a method to be used at temperatures between -50 and 200 C. Automatic calibration procedures developed to speed up the calibration process are outlined, and future possible extensions of system software are indicated.
Updating the HST/ACS G800L Grism Calibration
Hathi, Nimish P.; Pirzkal, Norbert; Grogin, Norman A.; Chiaberge, Marco; ACS Team
We present results from our ongoing work on obtaining newly derived trace and wavelength calibrations of the HST/ACS G800L grism and comparing them to previous set of calibrations. Past calibration efforts were based on 2003 observations. New observations of an emission line Wolf-Rayet star (WR96) were recently taken in HST Cycle 25 (PID: 15401). These observations are used to analyze and measure various grism properties, including wavelength calibration, spectral trace/tilt, length/size of grism orders, and spacing between various grism orders. To account for the field dependence, we observe WR96 at 3 different observing positions over the HST/ACS field of view. The three locations are the center of chip 1, the center of chip 2, and the center of the WFC1A-2K subarray (center of WFC Amp A on chip 1). This new data will help us to evaluate any differences in the G800L grism properties compared to previous calibration data, and to apply improved data analysis techniques to update these old measurements.
Laparoscopy After Previous Laparotomy
Directory of Open Access Journals (Sweden)
Zulfo Godinjak
Full Text Available Following the abdominal surgery, extensive adhesions often occur and they can cause difficulties during laparoscopic operations. However, previous laparotomy is not considered to be a contraindication for laparoscopy. The aim of this study is to present that an insertion of Veres needle in the region of umbilicus is a safe method for creating a pneumoperitoneum for laparoscopic operations after previous laparotomy. In the last three years, we have performed 144 laparoscopic operations in patients that previously underwent one or two laparotomies. Pathology of digestive system, genital organs, Cesarean Section or abdominal war injuries were the most common causes of previouslaparotomy. During those operations or during entering into abdominal cavity we have not experienced any complications, while in 7 patients we performed conversion to laparotomy following the diagnostic laparoscopy. In all patients an insertion of Veres needle and trocar insertion in the umbilical region was performed, namely a technique of closed laparoscopy. Not even in one patient adhesions in the region of umbilicus were found, and no abdominal organs were injured.
Directory of Open Access Journals (Sweden)
Frederick Schauer
Full Text Available Objective to study the notion and essence of legal judgments calibration the possibilities of using it in the lawenforcement activity to explore the expenses and advantages of using it. Methods dialectic approach to the cognition of social phenomena which enables to analyze them in historical development and functioning in the context of the integrity of objective and subjective factors it determined the choice of the following research methods formallegal comparative legal sociological methods of cognitive psychology and philosophy. Results In ordinary life people who assess other peoplersaquos judgments typically take into account the other judgments of those they are assessing in order to calibrate the judgment presently being assessed. The restaurant and hotel rating website TripAdvisor is exemplary because it facilitates calibration by providing access to a raterrsaquos previous ratings. Such information allows a user to see whether a particular rating comes from a rater who is enthusiastic about every place she patronizes or instead from someone who is incessantly hard to please. And even when less systematized as in assessing a letter of recommendation or college transcript calibration by recourse to the decisional history of those whose judgments are being assessed is ubiquitous. Yet despite the ubiquity and utility of such calibration the legal system seems perversely to reject it. Appellate courts do not openly adjust their standard of review based on the previous judgments of the judge whose decision they are reviewing nor do judges in reviewing legislative or administrative decisions magistrates in evaluating search warrant representations or jurors in assessing witness perception. In most legal domains calibration by reference to the prior decisions of the reviewee is invisible either because it does not exist or because reviewing bodies are unwilling to admit using what they in fact know and employ. Scientific novelty for the first
Vanzyl, J.
processing altitude or in the aircraft roll angle are possible causes of error in computing the antenna patterns inside the processor. POLCAL uses an altitude error correction algorithm to correctly remove the antenna pattern from the SAR images. POLCAL also uses a topographic calibration algorithm to reduce calibration errors resulting from ground topography. By utilizing the backscatter measurements from either the corner reflectors or a well-known distributed target, POLCAL can correct the residual amplitude offsets in the various polarization channels and correct for the absolute gain of the radar system. POLCAL also gives the user the option of calibrating a scene using the calibration data from a nearby site. This allows precise calibration of all the scenes acquired on a flight line where corner reflectors were present. Construction and positioning of corner reflectors is covered extensively in the program documentation. In an effort to keep the POLCAL code as transportable as possible, the authors eliminated all interactions with a graphics display system. For this reason, it is assumed that users will have their own software for doing the following: (1) synthesize an image using HH or VV polarization, (2) display the synthesized image on any display device, and (3) read the pixel locations of the corner reflectors from the image. The only inputs used by the software (in addition to the input Stokes matrix data file) is a small data file with the corner reflector information. POLCAL is written in FORTRAN 77 for use on Sun series computers running SunOS and DEC VAX computers running VMS. It requires 4Mb of RAM under SunOS and 3.7Mb of RAM under VMS for execution. The standard distribution medium for POLCAL is a .25 inch streaming magnetic tape cartridge in UNIX tar format. It is also available on a 9-track 1600 BPI magnetic tape in DEC VAX FILES-11 format or on a TK50 tape cartridge in DEC VAX FILES-11 format. Other distribution media may be available upon request
Stochastic calibration and learning in nonstationary hydroeconomic models
Maneta, M. P.; Howitt, R.
Concern about water scarcity and adverse climate events over agricultural regions has motivated a number of efforts to develop operational integrated hydroeconomic models to guide adaptation and optimal use of water. Once calibrated, these models are used for water management and analysis assuming they remain valid under future conditions. In this paper, we present and demonstrate a methodology that permits the recursive calibration of economic models of agricultural production from noisy but frequently available data. We use a standard economic calibration approach, namely positive mathematical programming, integrated in a data assimilation algorithm based on the ensemble Kalman filter equations to identify the economic model parameters. A moving average kernel ensures that new and past information on agricultural activity are blended during the calibration process, avoiding loss of information and overcalibration for the conditions of a single year. A regularization constraint akin to the standard Tikhonov regularization is included in the filter to ensure its stability even in the presence of parameters with low sensitivity to observations. The results show that the implementation of the PMP methodology within a data assimilation framework based on the enKF equations is an effective method to calibrate models of agricultural production even with noisy information. The recursive nature of the method incorporates new information as an added value to the known previous observations of agricultural activity without the need to store historical information. The robustness of the method opens the door to the use of new remote sensing algorithms for operational water management.
Mercury Continuous Emmission Monitor Calibration
Energy Technology Data Exchange (ETDEWEB)
John Schabron; Eric Kalberer; Ryan Boysen; William Schuster; Joseph Rovani
Mercury continuous emissions monitoring systems (CEMs) are being implemented in over 800 coal-fired power plant stacks throughput the U.S. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor calibrators/generators. These devices are used to calibrate mercury CEMs at power plant sites. The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005 and vacated by a Federal appeals court in early 2008 required that calibration be performed with NIST-traceable standards. Despite the vacature, mercury emissions regulations in the future will require NIST traceable calibration standards, and EPA does not want to interrupt the effort towards developing NIST traceability protocols. The traceability procedures will be defined by EPA. An initial draft traceability protocol was issued by EPA in May 2007 for comment. In August 2007, EPA issued a conceptual interim traceability protocol for elemental mercury calibrators. The protocol is based on the actual analysis of the output of each calibration unit at several concentration levels ranging initially from about 2-40 {micro}g/m{sup 3} elemental mercury, and in the future down to 0.2 {micro}g/m{sup 3}, and this analysis will be directly traceable to analyses by NIST. The EPA traceability protocol document is divided into two separate sections. The first deals with the qualification of calibrator models by the vendors for use in mercury CEM calibration. The second describes the procedure that the vendors must use to certify the calibrators that meet the qualification specifications. The NIST traceable certification is performance based, traceable to analysis using isotope dilution inductively coupled plasma
Landsat-8 Sensor Characterization and Calibration
Directory of Open Access Journals (Sweden)
Brian Markham
Full Text Available Landsat-8 was launched on 11 February 2013 with two new Earth Imaging sensors to provide a continued data record with the previous Landsats. For Landsat-8, pushbroom technology was adopted, and the reflective bands and thermal bands were split into two instruments. The Operational Land Imager (OLI is the reflective band sensor and the Thermal Infrared Sensor (TIRS, the thermal. In addition to these fundamental changes, bands were added, spectral bandpasses were refined, dynamic range and data quantization were improved, and numerous other enhancements were implemented. As in previous Landsat missions, the National Aeronautics and Space Administration (NASA and United States Geological Survey (USGS cooperated in the development, launch and operation of the Landsat-8 mission. One key aspect of this cooperation was in the characterization and calibration of the instruments and their data. This Special Issue documents the efforts of the joint USGS and NASA calibration team and affiliates to characterize the new sensors and their data for the benefit of the scientific and application users of the Landsat archive. A key scientific use of Landsat data is to assess changes in the land-use and land cover of the Earth's surface over the now 43-year record. [...
International Nuclear Information System (INIS)
Ghezzehej, T.
The purpose of this model report is to document the calibrated properties model that provides calibrated property sets for unsaturated zone (UZ) flow and transport process models (UZ models). The calibration of the property sets is performed through inverse modeling. This work followed, and was planned in, ''Technical Work Plan (TWP) for: Unsaturated Zone Flow Analysis and Model Report Integration'' (BSC 2004 [DIRS 169654], Sections 1.2.6 and 22.214.171.124). Direct inputs to this model report were derived from the following upstream analysis and model reports: ''Analysis of Hydrologic Properties Data'' (BSC 2004 [DIRS 170038]); ''Development of Numerical Grids for UZ Flow and Transport Modeling'' (BSC 2004 [DIRS 169855]); ''Simulation of Net Infiltration for Present-Day and Potential Future Climates'' (BSC 2004 [DIRS 170007]); ''Geologic Framework Model'' (GFM2000) (BSC 2004 [DIRS 170029]). Additionally, this model report incorporates errata of the previous version and closure of the Key Technical Issue agreement TSPAI 3.26 (Section 6.2.2 and Appendix B), and it is revised for improved transparency
Development of pre-critical excore detector linear subchannel calibration method
International Nuclear Information System (INIS)
Choi, Yoo Sun; Goo, Bon Seung; Cha, Kyun Ho; Lee, Chang Seop; Kim, Yong Hee; Ahn, Chul Soo; Kim, Man Soo
The improved pre-critical excore detector linear subchannel calibration method has been developed to improve the applicability of pre-critical calibration method. The existing calibration method does not always guarantee the accuracy of pre-critical calibration because the calibration results of the previous cycle are not reflected into the current cycle calibration. The developed method has a desirable feature that calibration error would not be propagated in the following cycles since the calibration data determined in previous cycle is incorporated in the current cycle calibration. The pre-critical excore detector linear calibration is tested for YGN unit 3 and UCN unit 3 to evaluate its characteristics and accuracy
Scalar Calibration of Vector Magnetometers
DEFF Research Database (Denmark)
Merayo, José M.G.; Brauer, Peter; Primdahl, Fritz
The calibration parameters of a vector magnetometer are estimated only by the use of a scalar reference magnetometer. The method presented in this paper differs from those previously reported in its linearized parametrization. This allows the determination of three offsets or signals in the absence...
Estimation of inspection effort
International Nuclear Information System (INIS)
Mullen, M.F.; Wincek, M.A.
An overview of IAEA inspection activities is presented, and the problem of evaluating the effectiveness of an inspection is discussed. Two models are described - an effort model and an effectiveness model. The effort model breaks the IAEA's inspection effort into components; the amount of effort required for each component is estimated; and the total effort is determined by summing the effort for each component. The effectiveness model quantifies the effectiveness of inspections in terms of probabilities of detection and quantities of material to be detected, if diverted over a specific period. The method is applied to a 200 metric ton per year low-enriched uranium fuel fabrication facility. A description of the model plant is presented, a safeguards approach is outlined, and sampling plans are calculated. The required inspection effort is estimated and the results are compared to IAEA estimates. Some other applications of the method are discussed briefly. Examples are presented which demonstrate how the method might be useful in formulating guidelines for inspection planning and in establishing technical criteria for safeguards implementation
Effort in Multitasking: Local and Global Assessment of Effort.
Kiesel, Andrea; Dignath, David
When performing multiple tasks in succession, self-organization of task order might be superior compared to external-controlled task schedules, because self-organization allows optimizing processing modes and thus reduces switch costs, and it increases commitment to task goals. However, self-organization is an additional executive control process that is not required if task order is externally specified and as such it is considered as time-consuming and effortful. To compare self-organized and externally controlled task scheduling, we suggest assessing global subjective and objectives measures of effort in addition to local performance measures. In our new experimental approach, we combined characteristics of dual tasking settings and task switching settings and compared local and global measures of effort in a condition with free choice of task sequence and a condition with cued task sequence. In a multi-tasking environment, participants chose the task order while the task requirement of the not-yet-performed task remained the same. This task preview allowed participants to work on the previously non-chosen items in parallel and resulted in faster responses and fewer errors in task switch trials than in task repetition trials. The free-choice group profited more from this task preview than the cued group when considering local performance measures. Nevertheless, the free-choice group invested more effort than the cued group when considering global measures. Thus, self-organization in task scheduling seems to be effortful even in conditions in which it is beneficiary for task processing. In a second experiment, we reduced the possibility of task preview for the not-yet-performed tasks in order to hinder efficient self-organization. Here neither local nor global measures revealed substantial differences between the free-choice and a cued task sequence condition. Based on the results of both experiments, we suggest that global assessment of effort in addition to
Energy Technology Data Exchange (ETDEWEB)
John Schabron; Joseph Rovani; Mark Sanderson
outputs of mercury generators are compared to one another using a nesting procedure which allows direct comparison of one generator with another and eliminates analyzer variability effects. The qualification portion of the EPA interim traceability protocol requires the vendors to define generator performance as affected by variables such as pressure, temperature, line voltage, and shipping. WRI is focusing efforts to determine actual generator performance related to the variables defined in the qualification portion of the interim protocol. The protocol will then be further revised by EPA based on what can actually be achieved with the generators. Another focus of the study is to evaluate approaches for field verification of generator performance. Upcoming work includes evaluation of oxidized mercury calibration generators, for which a separate protocol will be prepared by EPA. In addition, the variability of the spectrometers/analyzers under various environmental conditions needs to be defined and understood better. A main objective of the current work is to provide data on the performance and capabilities of elemental mercury generator/calibration systems for the development of realistic NIST traceability protocols for mercury vapor standards for continuous emission CEM calibration. This work is providing a direct contribution to the enablement of continuous emissions monitoring at coal-fired power plants in conformance with the CAMR. EPA Specification 12 states that mercury CEMs must be calibrated with NIST-traceable standards (Federal Register 2005). The initial draft of an elemental mercury generator traceability protocol was circulated by EPA in May 2007 for comment, and an interim protocol was issued in August 2007 (EPA 2007). Initially it was assumed that the calibration and implementation of mercury CEMs would be relatively simple, and implementation would follow the implementation of the Clean Air Interstate Rule (CAIR) SO{sub 2} and NO{sub x} monitoring, and
Absolute calibration in vivo measurement systems
International Nuclear Information System (INIS)
Kruchten, D.A.; Hickman, D.P.
Lawrence Livermore National Laboratory (LLNL) is currently investigating a new method for obtaining absolute calibration factors for radiation measurement systems used to measure internally deposited radionuclides in vivo. Absolute calibration of in vivo measurement systems will eliminate the need to generate a series of human surrogate structures (i.e., phantoms) for calibrating in vivo measurement systems. The absolute calibration of in vivo measurement systems utilizes magnetic resonance imaging (MRI) to define physiological structure, size, and composition. The MRI image provides a digitized representation of the physiological structure, which allows for any mathematical distribution of radionuclides within the body. Using Monte Carlo transport codes, the emission spectrum from the body is predicted. The in vivo measurement equipment is calibrated using the Monte Carlo code and adjusting for the intrinsic properties of the detection system. The calibration factors are verified using measurements of existing phantoms and previously obtained measurements of human volunteers. 8 refs
International Nuclear Information System (INIS)
Waller, W.C.; Cram, M.E.; Hall, J.E.
For any measurement to have meaning, it must be related to generally accepted standard units by a valid and specified system of comparison. To calibrate well-logging tools, sensing systems are designed which produce consistent and repeatable indications over the range for which the tool was intended. The basics of calibration theory, procedures, and calibration record presentations are reviewed. Calibrations for induction, electrical, radioactivity, and sonic logging tools will be discussed. The authors' intent is to provide an understanding of the sources of errors, of the way errors are minimized in the calibration process, and of the significance of changes in recorded calibration data
Calibration of IR test chambers with the missile defense transfer radiometer
Kaplan, Simon G.; Woods, Solomon I.; Carter, Adriaan C.; Jung, Timothy M.
The Missile Defense Transfer Radiometer (MDXR) is designed to calibrate infrared collimated and flood sources over the fW/cm2 to W/cm2 power range from 3 μm to 28μ m in wavelength. The MDXR operates in three different modes: as a filter radiometer, a Fourier-transform spectrometer (FTS)-based spectroradiometer, and as an absolute cryogenic radiometer (ACR). Since 2010, the MDXR has made measurements of the collimated infrared irradiance at the output port of seven different infrared test chambers at several facilities. We present a selection of results from these calibration efforts compared to signal predictions from the respective chamber models for the three different MDXR calibration modes. We also compare the results to previous measurements made of the same chambers with a legacy transfer radiometer, the NIST BXR. In general, the results are found to agree within their combined uncertainties, with the MDXR having 30 % lower uncertainty and greater spectral coverage.
Synthesis Polarimetry Calibration
Moellenbrock, George
Synthesis instrumental polarization calibration fundamentals for both linear (ALMA) and circular (EVLA) feed bases are reviewed, with special attention to the calibration heuristics supported in CASA. Practical problems affecting modern instruments are also discussed.
International Nuclear Information System (INIS)
Berger, C.D.; Gupton, E.D.; Lane, B.H.; Miller, J.H.; Nichols, S.W.
The ORNL Calibrations Facility is operated by the Instrumentation Group of the Industrial Safety and Applied Health Physics Division. Its primary purpose is to maintain radiation calibration standards for calibration of ORNL health physics instruments and personnel dosimeters. This report includes a discussion of the radioactive sources and ancillary equipment in use and a step-by-step procedure for calibration of those survey instruments and personnel dosimeters in routine use at ORNL
SDSS-IV/MaNGA: SPECTROPHOTOMETRIC CALIBRATION TECHNIQUE
Energy Technology Data Exchange (ETDEWEB)
Yan, Renbin; Sánchez-Gallego, José R. [Department of Physics and Astronomy, University of Kentucky, 505 Rose St., Lexington, KY 40506-0057 (United States); Tremonti, Christy; Bershady, Matthew A.; Eigenbrot, Arthur; Wake, David A. [Department of Astronomy, University of Winsconsin-Madison, 475 N. Charter Street, Madison, WI 53706-1582 (United States); Law, David R. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Schlegel, David J. [Physics Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8160 (United States); Bundy, Kevin [Kavli IPMU (WPI), UTIAS, The University of Tokyo, Kashiwa, Chiba 277-8583 (Japan); Drory, Niv [McDonald Observatory, Department of Astronomy, University of Texas at Austin, 1 University Station, Austin, TX 78712-0259 (United States); MacDonald, Nicholas [Department of Astronomy, Box 351580, University of Washington, Seattle, WA 98195 (United States); Bizyaev, Dmitry [Apache Point Observatory, P.O. Box 59, sunspot, NM 88349 (United States); Blanc, Guillermo A. [Departamento de Astronomía, Universidad de Chile, Camino el Observatorio 1515, Las Condes, Santiago (Chile); Blanton, Michael R.; Hogg, David W. [Center for Cosmology and Particle Physics, Department of Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Cherinka, Brian [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, Ontario M5S 3H4 (Canada); Gunn, James E. [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States); Harding, Paul [Department of Astronomy, Case Western Reserve University, Cleveland, OH 44106 (United States); Sánchez, Sebastian F., E-mail: firstname.lastname@example.com [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, A.P. 70-264, 04510 Mexico D.F. (Mexico); and others
Mapping Nearby Galaxies at Apache Point Observatory (MaNGA), one of three core programs in the Sloan Digital Sky Survey-IV, is an integral-field spectroscopic survey of roughly 10,000 nearby galaxies. It employs dithered observations using 17 hexagonal bundles of 2″ fibers to obtain resolved spectroscopy over a wide wavelength range of 3600–10300 Å. To map the internal variations within each galaxy, we need to perform accurate spectral surface photometry, which is to calibrate the specific intensity at every spatial location sampled by each individual aperture element of the integral field unit. The calibration must correct only for the flux loss due to atmospheric throughput and the instrument response, but not for losses due to the finite geometry of the fiber aperture. This requires the use of standard star measurements to strictly separate these two flux loss factors (throughput versus geometry), a difficult challenge with standard single-fiber spectroscopy techniques due to various practical limitations. Therefore, we developed a technique for spectral surface photometry using multiple small fiber-bundles targeting standard stars simultaneously with galaxy observations. We discuss the principles of our approach and how they compare to previous efforts, and we demonstrate the precision and accuracy achieved. MaNGA's relative calibration between the wavelengths of Hα and Hβ has an rms of 1.7%, while that between [N ii] λ6583 and [O ii] λ3727 has an rms of 4.7%. Using extinction-corrected star formation rates and gas-phase metallicities as an illustration, this level of precision guarantees that flux calibration errors will be sub-dominant when estimating these quantities. The absolute calibration is better than 5% for more than 89% of MaNGA's wavelength range.
SDSS-IV/MaNGA: SPECTROPHOTOMETRIC CALIBRATION TECHNIQUE
International Nuclear Information System (INIS)
Yan, Renbin; Sánchez-Gallego, José R.; Tremonti, Christy; Bershady, Matthew A.; Eigenbrot, Arthur; Wake, David A.; Law, David R.; Schlegel, David J.; Bundy, Kevin; Drory, Niv; MacDonald, Nicholas; Bizyaev, Dmitry; Blanc, Guillermo A.; Blanton, Michael R.; Hogg, David W.; Cherinka, Brian; Gunn, James E.; Harding, Paul; Sánchez, Sebastian F.
Mapping Nearby Galaxies at Apache Point Observatory (MaNGA), one of three core programs in the Sloan Digital Sky Survey-IV, is an integral-field spectroscopic survey of roughly 10,000 nearby galaxies. It employs dithered observations using 17 hexagonal bundles of 2″ fibers to obtain resolved spectroscopy over a wide wavelength range of 3600–10300 Å. To map the internal variations within each galaxy, we need to perform accurate spectral surface photometry, which is to calibrate the specific intensity at every spatial location sampled by each individual aperture element of the integral field unit. The calibration must correct only for the flux loss due to atmospheric throughput and the instrument response, but not for losses due to the finite geometry of the fiber aperture. This requires the use of standard star measurements to strictly separate these two flux loss factors (throughput versus geometry), a difficult challenge with standard single-fiber spectroscopy techniques due to various practical limitations. Therefore, we developed a technique for spectral surface photometry using multiple small fiber-bundles targeting standard stars simultaneously with galaxy observations. We discuss the principles of our approach and how they compare to previous efforts, and we demonstrate the precision and accuracy achieved. MaNGA's relative calibration between the wavelengths of Hα and Hβ has an rms of 1.7%, while that between [N ii] λ6583 and [O ii] λ3727 has an rms of 4.7%. Using extinction-corrected star formation rates and gas-phase metallicities as an illustration, this level of precision guarantees that flux calibration errors will be sub-dominant when estimating these quantities. The absolute calibration is better than 5% for more than 89% of MaNGA's wavelength range
Calibration strategies for the Cherenkov Telescope Array
Gaug, Markus; Berge, David; Daniel, Michael; Doro, Michele; Förster, Andreas; Hofmann, Werner; Maccarone, Maria C.; Parsons, Dan; de los Reyes Lopez, Raquel; van Eldik, Christopher
The Central Calibration Facilities workpackage of the Cherenkov Telescope Array (CTA) observatory for very high energy gamma ray astronomy defines the overall calibration strategy of the array, develops dedicated hardware and software for the overall array calibration and coordinates the calibration efforts of the different telescopes. The latter include LED-based light pulsers, and various methods and instruments to achieve a calibration of the overall optical throughput. On the array level, methods for the inter-telescope calibration and the absolute calibration of the entire observatory are being developed. Additionally, the atmosphere above the telescopes, used as a calorimeter, will be monitored constantly with state-of-the-art instruments to obtain a full molecular and aerosol profile up to the stratosphere. The aim is to provide a maximal uncertainty of 10% on the reconstructed energy-scale, obtained through various independent methods. Different types of LIDAR in combination with all-sky-cameras will provide the observatory with an online, intelligent scheduling system, which, if the sky is partially covered by clouds, gives preference to sources observable under good atmospheric conditions. Wide-field optical telescopes and Raman Lidars will provide online information about the height-resolved atmospheric extinction, throughout the field-of-view of the cameras, allowing for the correction of the reconstructed energy of each gamma-ray event. The aim is to maximize the duty cycle of the observatory, in terms of usable data, while reducing the dead time introduced by calibration activities to an absolute minimum.
MacDonald, F. A.; Schmitz, M. D.; Crowley, J. L.; Haam, E.; Huybers, P.; Cohen, P. A.; Johnston, D. T.
The IGCP 512 sub-commission on the Neoproterozoic is currently discussing criteria for the definition of the Cryogenian period. Herein we provide new U/Pb ID-TIMS ages and carbon and oxygen isotope data from Fifteenmile and Mt. Harper Groups in the Yukon Territory that inform the basis for the placement of the basal Cryogenian "golden spike". Our U/Pb ages are from volcanic tuffs interbedded within glaciogenic, fossiliferous, and carbonate strata. With the current lack of Neoproterozoic index fossils and the paucity of radiogenic age constraints, chemo-stratigraphic correlations are particularly important for tuning the Neoproterozoic timescale. In an effort to move beyond conventional 'wiggle matching', chemostratigraphic correlations are determined using a new statistical method1, which indicates that the resulting chemo-stratigraphic correlations are statistically significant. These results permit us to refine and integrate Neoproterozoic climate, microfossil, and geochemical proxy records both regionally and globally. The newly calibrated microfossil record points to a eukaryotic radiation roughly coincident with the Bitter Springs isotopic stage and a barren interval between the Sturtian and Marinoan glaciations. 1 Haam, E. & Huybers, P., 2009, A test for the presence of covariance between time-uncertain series of data with applications to the Dongge Cave speleothem and atmospheric radiocarbon records, Paleoceanography, in press.
Investigation of a Fiber Optic Strain Sensing (FOSS) Distributed Load Calibration Methodology
National Aeronautics and Space Administration — FOSS is a relatively newer technology that needs to be explored for application to load calibration and loads monitoring efforts. Load calibration opportunities are...
A survey of previous and current industry-wide efforts regarding burnup credit
International Nuclear Information System (INIS)
Jones, R.H.
Sandia has examined the matter of burnup credit from the perspective of physics, logistics, risk, and economics. A limited survey of the nuclear industry has been conducted to get a feeling for the actual application of burnup credit. Based on this survey, it can be concluded that the suppliers of spent fuel storage and transport casks are in general agreement that burnup credit offers the potential for improvements in cask efficiency without increasing the risk of accidental criticality. The actual improvement is design-specific but limited applications have demonstrated that capacity increases in the neighborhood of 20 percent are not unrealistic. A number of these vendors acknowledge that burnup credit has not been reduced to practice in cask applications and suggest that operational considerations may be more important to regulatory acceptance than to the physics. Nevertheless, the importance of burnup credit to the nuclear industry as a cask design and analysis tool has been confirmed by this survey
Temperature corrected-calibration of GRACE's accelerometer
Encarnacao, J.; Save, H.; Siemes, C.; Doornbos, E.; Tapley, B. D.
Since April 2011, the thermal control of the accelerometers on board the GRACE satellites has been turned off. The time series of along-track bias clearly show a drastic change in the behaviour of this parameter, while the calibration model has remained unchanged throughout the entire mission lifetime. In an effort to improve the quality of the gravity field models produced at CSR in future mission-long re-processing of GRACE data, we quantify the added value of different calibration strategies. In one approach, the temperature effects that distort the raw accelerometer measurements collected without thermal control are corrected considering the housekeeping temperature readings. In this way, one single calibration strategy can be consistently applied during the whole mission lifetime, since it is valid to thermal the conditions before and after April 2011. Finally, we illustrate that the resulting calibrated accelerations are suitable for neutral thermospheric density studies.
Calibration of higher eigenmodes of cantilevers
International Nuclear Information System (INIS)
Labuda, Aleksander; Kocun, Marta; Walsh, Tim; Meinhold, Jieh; Proksch, Tania; Meinhold, Waiman; Anderson, Caleb; Proksch, Roger; Lysy, Martin
A method is presented for calibrating the higher eigenmodes (resonant modes) of atomic force microscopy cantilevers that can be performed prior to any tip-sample interaction. The method leverages recent efforts in accurately calibrating the first eigenmode by providing the higher-mode stiffness as a ratio to the first mode stiffness. A one-time calibration routine must be performed for every cantilever type to determine a power-law relationship between stiffness and frequency, which is then stored for future use on similar cantilevers. Then, future calibrations only require a measurement of the ratio of resonant frequencies and the stiffness of the first mode. This method is verified through stiffness measurements using three independent approaches: interferometric measurement, AC approach-curve calibration, and finite element analysis simulation. Power-law values for calibrating higher-mode stiffnesses are reported for several cantilever models. Once the higher-mode stiffnesses are known, the amplitude of each mode can also be calibrated from the thermal spectrum by application of the equipartition theorem.
Calibration of higher eigenmodes of cantilevers
Energy Technology Data Exchange (ETDEWEB)
Labuda, Aleksander; Kocun, Marta; Walsh, Tim; Meinhold, Jieh; Proksch, Tania; Meinhold, Waiman; Anderson, Caleb; Proksch, Roger [Asylum Research, an Oxford Instruments Company, Santa Barbara, California 93117 (United States); Lysy, Martin [Department of Statistics and Actuarial Science, University of Waterloo, Waterloo, Ontario N2L 3G1 (Canada)
A method is presented for calibrating the higher eigenmodes (resonant modes) of atomic force microscopy cantilevers that can be performed prior to any tip-sample interaction. The method leverages recent efforts in accurately calibrating the first eigenmode by providing the higher-mode stiffness as a ratio to the first mode stiffness. A one-time calibration routine must be performed for every cantilever type to determine a power-law relationship between stiffness and frequency, which is then stored for future use on similar cantilevers. Then, future calibrations only require a measurement of the ratio of resonant frequencies and the stiffness of the first mode. This method is verified through stiffness measurements using three independent approaches: interferometric measurement, AC approach-curve calibration, and finite element analysis simulation. Power-law values for calibrating higher-mode stiffnesses are reported for several cantilever models. Once the higher-mode stiffnesses are known, the amplitude of each mode can also be calibrated from the thermal spectrum by application of the equipartition theorem.
Calibration of Flick standards
International Nuclear Information System (INIS)
Thalmann, Ruedi; Spiller, Jürg; Küng, Alain; Jusko, Otto
Flick standards or magnification standards are widely used for an efficient and functional calibration of the sensitivity of form measuring instruments. The results of a recent measurement comparison have shown to be partially unsatisfactory and revealed problems related to the calibration of these standards. In this paper the influence factors for the calibration of Flick standards using roundness measurement instruments are discussed in detail, in particular the bandwidth of the measurement chain, residual form errors of the device under test, profile distortions due to the diameter of the probing element and questions related to the definition of the measurand. The different contributions are estimated using simulations and are experimentally verified. Also alternative methods to calibrate Flick standards are investigated. Finally the practical limitations of Flick standard calibration are shown and the usability of Flick standards both to calibrate the sensitivity of roundness instruments and to check the filter function of such instruments is analysed. (paper)
Improvements to the RXTE/PCA Calibration
Jahoda, K.
The author presents the current status of the RXTE/PCA Calibration, with emphasis on recent updates to the energy scale and the background subtraction. A new treatment of the Xenon K-escape line removes the largest remaining residual in the previously distributed matrices. Observations of Sco X-1 made simultaneously with Swift XRT, expressly for the purpose of cross calibrating the response to bright sources, are presented.
RF impedance measurement calibration
International Nuclear Information System (INIS)
Matthews, P.J.; Song, J.J.
The intent of this note is not to explain all of the available calibration methods in detail. Instead, we will focus on the calibration methods of interest for RF impedance coupling measurements and attempt to explain: (1). The standards and measurements necessary for the various calibration techniques. (2). The advantages and disadvantages of each technique. (3). The mathematical manipulations that need to be applied to the measured standards and devices. (4). An outline of the steps needed for writing a calibration routine that operated from a remote computer. For further details of the various techniques presented in this note, the reader should consult the references
Calculus detection calibration among dental hygiene faculty members utilizing dental endoscopy: a pilot study.
Partido, Brian B; Jones, Archie A; English, Dana L; Nguyen, Carol A; Jacks, Mary E
Dental and dental hygiene faculty members often do not provide consistent instruction in the clinical environment, especially in tasks requiring clinical judgment. From previous efforts to calibrate faculty members in calculus detection using typodonts, researchers have suggested using human subjects and emerging technology to improve consistency in clinical instruction. The purpose of this pilot study was to determine if a dental endoscopy-assisted training program would improve intra- and interrater reliability of dental hygiene faculty members in calculus detection. Training included an ODU 11/12 explorer, typodonts, and dental endoscopy. A convenience sample of six participants was recruited from the dental hygiene faculty at a California community college, and a two-group randomized experimental design was utilized. Intra- and interrater reliability was measured before and after calibration training. Pretest and posttest Kappa averages of all participants were compared using repeated measures (split-plot) ANOVA to determine the effectiveness of the calibration training on intra- and interrater reliability. The results showed that both kinds of reliability significantly improved for all participants and the training group improved significantly in interrater reliability from pretest to posttest. Calibration training was beneficial to these dental hygiene faculty members, especially those beginning with less than full agreement. This study suggests that calculus detection calibration training utilizing dental endoscopy can effectively improve interrater reliability of dental and dental hygiene clinical educators. Future studies should include human subjects, involve more participants at multiple locations, and determine whether improved rater reliability can be sustained over time.
Literality and Cognitive Effort
DEFF Research Database (Denmark)
Lacruz, Isabel; Carl, Michael; Yamada, Masaru
We introduce a notion of pause-word ratio computed using ranges of pause lengths rather than lower cutoffs for pause lengths. Standard pause-word ratios are indicators of cognitive effort during different translation modalities.The pause range version allows for the study of how different types...... remoteness. We use data from the CRITT TPR database, comparing translation and post-editing from English to Japanese and from English to Spanish, and study the interaction of pause-word ratio for short pauses ranging between 300 and 500ms with syntactic remoteness, measured by the CrossS feature, semantic...... remoteness, measured by HTra, and syntactic and semantic remoteness, measured by Literality....
Breckinridge Project, initial effort
Energy Technology Data Exchange (ETDEWEB)
None, None
Report III, Volume 1 contains those specifications numbered A through J, as follows: General Specifications (A); Specifications for Pressure Vessels (C); Specifications for Tanks (D); Specifications for Exchangers (E); Specifications for Fired Heaters (F); Specifications for Pumps and Drivers (G); and Specifications for Instrumentation (J). The standard specifications of Bechtel Petroleum Incorporated have been amended as necessary to reflect the specific requirements of the Breckinridge Project, and the more stringent specifications of Ashland Synthetic Fuels, Inc. These standard specifications are available to the Initial Effort (Phase Zero) work performed by all contractors and subcontractors. Report III, Volume 1 also contains the unique specifications prepared for Plants 8, 15, and 27. These specifications will be substantially reviewed during Phase I of the project, and modified as necessary for use during the engineering, procurement, and construction of this project.
DEFF Research Database (Denmark)
Kierkegaard, Patrick
are being utilized? What medical disciplines are being addressed using telemedicine systems? Methods: All data was surveyed from the "Telemedicinsk Landkort", a newly created database designed to provide a comprehensive and systematic overview of all telemedicine technologies in Denmark. Results......Objectives: The aim of this study is to survey telemedicine services currently in operation across Denmark. The study specifically seeks to answer the following questions: What initiatives are deployed within the different regions? What are the motivations behind the projects? What technologies......: The results of this study suggest that a growing number of telemedicine initiatives are currently in operation across Denmark but that considerable variations existed in terms of regional efforts as the number of operational telemedicine projects varied from region to region. Conclusions: The results...
Bayesian Calibration of Thermodynamic Databases and the Role of Kinetics
Wolf, A. S.; Ghiorso, M. S.
Self-consistent thermodynamic databases of geologically relevant materials (like Berman, 1988; Holland and Powell, 1998, Stixrude & Lithgow-Bertelloni 2011) are crucial for simulating geological processes as well as interpreting rock samples from the field. These databases form the backbone of our understanding of how fluids and rocks interact at extreme planetary conditions. Considerable work is involved in their construction from experimental phase reaction data, as they must self-consistently describe the free energy surfaces (including relative offsets) of potentially hundreds of interacting phases. Standard database calibration methods typically utilize either linear programming or least squares regression. While both produce a viable model, they suffer from strong limitations on the training data (which must be filtered by hand), along with general ignorance of many of the sources of experimental uncertainty. We develop a new method for calibrating high P-T thermodynamic databases for use in geologic applications. The model is designed to handle pure solid endmember and free fluid phases and can be extended to include mixed solid solutions and melt phases. This new calibration effort utilizes Bayesian techniques to obtain optimal parameter values together with a full family of statistically acceptable models, summarized by the posterior. Unlike previous efforts, the Bayesian Logistic Uncertain Reaction (BLUR) model directly accounts for both measurement uncertainties and disequilibrium effects, by employing a kinetic reaction model whose parameters are empirically determined from the experiments themselves. Thus, along with the equilibrium free energy surfaces, we also provide rough estimates of the activation energies, entropies, and volumes for each reaction. As a first application, we demonstrate this new method on the three-phase aluminosilicate system, illustrating how it can produce superior estimates of the phase boundaries by incorporating constraints
Calibration of moisture monitors
International Nuclear Information System (INIS)
Gutierrez, R.L.
A method for calibrating an aluminum oxide hygrometer against an optical chilled mirror dew-point hygrometer has been established. A theoretical cross-point line of dew points from both hygrometers and a maximum moisture content of 10 ppM/sub v/ are used to define an area for calibrating the sensor probes of the aluminum oxide hygrometer
DEFF Research Database (Denmark)
Yordanova, Ginka; Vesth, Allan
The report describes site calibration measurements carried out on a site in Denmark. The measurements are carried out in accordance to Ref. [1]. The site calibration is carried out before a power performance measurement on a given turbine to clarify the influence from the terrain on the ratio...
Topics in Statistical Calibration
Natural cubic spline speed di st 110 B.2 The calibrate function The most basic calibration problem, the one often encountered in more advanced ...0040-1706, 1537-2723. A. M. Mood, F. A. Graybill, and D. C. Boes. Introduction to the Theory of Statistics. McGraw-Hill, Auckland , U.A, 1974. ISBN
Sandia WIPP calibration traceability
Energy Technology Data Exchange (ETDEWEB)
Schuhen, M.D. [Sandia National Labs., Albuquerque, NM (United States); Dean, T.A. [RE/SPEC, Inc., Albuquerque, NM (United States)
This report summarizes the work performed to establish calibration traceability for the instrumentation used by Sandia National Laboratories at the Waste Isolation Pilot Plant (WIPP) during testing from 1980-1985. Identifying the calibration traceability is an important part of establishing a pedigree for the data and is part of the qualification of existing data. In general, the requirement states that the calibration of Measuring and Test equipment must have a valid relationship to nationally recognized standards or the basis for the calibration must be documented. Sandia recognized that just establishing calibration traceability would not necessarily mean that all QA requirements were met during the certification of test instrumentation. To address this concern, the assessment was expanded to include various activities.
Energy Technology Data Exchange (ETDEWEB)
Baudis, Laura; Froborg, Francis; Tarka, Michael; Bruch, Tobias; Ferella, Alfredo [Physik-Institut, Universitaet Zuerich (Switzerland); Collaboration: GERDA-Collaboration
A system with three identical custom made units is used for the energy calibration of the GERDA Ge diodes. To perform a calibration the {sup 228}Th sources are lowered from the parking positions at the top of the cryostat. Their positions are measured by two independent modules. One, the incremental encoder, counts the holes in the perforated steel band holding the sources, the other measures the drive shaft's angular position even if not powered. The system can be controlled remotely by a Labview program. The calibration data is analyzed by an iterative calibration algorithm determining the calibration functions for different energy reconstruction algorithms and the resolution of several peaks in the {sup 228}Th spectrum is determined. A Monte Carlo simulation using the GERDA simulation software MAGE has been performed to determine the background induced by the sources in the parking positions.
Sandia WIPP calibration traceability
International Nuclear Information System (INIS)
Schuhen, M.D.; Dean, T.A.
This report summarizes the work performed to establish calibration traceability for the instrumentation used by Sandia National Laboratories at the Waste Isolation Pilot Plant (WIPP) during testing from 1980-1985. Identifying the calibration traceability is an important part of establishing a pedigree for the data and is part of the qualification of existing data. In general, the requirement states that the calibration of Measuring and Test equipment must have a valid relationship to nationally recognized standards or the basis for the calibration must be documented. Sandia recognized that just establishing calibration traceability would not necessarily mean that all QA requirements were met during the certification of test instrumentation. To address this concern, the assessment was expanded to include various activities
Robot-assisted automatic ultrasound calibration.
Aalamifar, Fereshteh; Cheng, Alexis; Kim, Younsu; Hu, Xiao; Zhang, Haichong K; Guo, Xiaoyu; Boctor, Emad M
Ultrasound (US) calibration is the process of determining the unknown transformation from a coordinate frame such as the robot's tooltip to the US image frame and is a necessary task for any robotic or tracked US system. US calibration requires submillimeter-range accuracy for most applications, but it is a time-consuming and repetitive task. We provide a new framework for automatic US calibration with robot assistance and without the need for temporal calibration. US calibration based on active echo (AE) phantom was previously proposed, and its superiority over conventional cross-wire phantom-based calibration was shown. In this work, we use AE to guide the robotic arm motion through the process of data collection; we combine the capability of the AE point to localize itself in the frame of the US image with the automatic motion of the robotic arm to provide a framework for calibrating the arm to the US image automatically. We demonstrated the efficacy of the automated method compared to the manual method through experiments. To highlight the necessity of frequent ultrasound calibration, it is demonstrated that the calibration precision changed from 1.67 to 3.20 mm if the data collection is not repeated after a dismounting/mounting of the probe holder. In a large data set experiment, similar reconstruction precision of automatic and manual data collection was observed, while the time was reduced by 58 %. In addition, we compared ten automatic calibrations with ten manual ones, each performed in 15 min, and showed that all the automatic ones could converge in the case of setting the initial matrix as identity, while this was not achieved by manual data sets. Given the same initial matrix, the repeatability of the automatic was [0.46, 0.34, 0.80, 0.47] versus [0.42, 0.51, 0.98, 1.15] mm in the manual case for the US image four corners. The submillimeter accuracy requirement of US calibration makes frequent data collections unavoidable. We proposed an automated
Shell Inspection History and Current CMM Inspection Efforts
Energy Technology Data Exchange (ETDEWEB)
Montano, Joshua Daniel [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
The following report provides a review of past and current CMM Shell Inspection efforts. Calibration of the Sheffield rotary contour gauge has expired and the primary inspector, Matthew Naranjo, has retired. Efforts within the Inspection team are transitioning from maintaining and training new inspectors on Sheffield to off-the-shelf CMM technology. Although inspection of a shell has many requirements, the scope of the data presented in this report focuses on the inner contour, outer contour, radial wall thickness and mass comparisons.
Previously unknown species of Aspergillus.
Gautier, M; Normand, A-C; Ranque, S
The use of multi-locus DNA sequence analysis has led to the description of previously unknown 'cryptic' Aspergillus species, whereas classical morphology-based identification of Aspergillus remains limited to the section or species-complex level. The current literature highlights two main features concerning these 'cryptic' Aspergillus species. First, the prevalence of such species in clinical samples is relatively high compared with emergent filamentous fungal taxa such as Mucorales, Scedosporium or Fusarium. Second, it is clearly important to identify these species in the clinical laboratory because of the high frequency of antifungal drug-resistant isolates of such Aspergillus species. Matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) has recently been shown to enable the identification of filamentous fungi with an accuracy similar to that of DNA sequence-based methods. As MALDI-TOF MS is well suited to the routine clinical laboratory workflow, it facilitates the identification of these 'cryptic' Aspergillus species at the routine mycology bench. The rapid establishment of enhanced filamentous fungi identification facilities will lead to a better understanding of the epidemiology and clinical importance of these emerging Aspergillus species. Based on routine MALDI-TOF MS-based identification results, we provide original insights into the key interpretation issues of a positive Aspergillus culture from a clinical sample. Which ubiquitous species that are frequently isolated from air samples are rarely involved in human invasive disease? Can both the species and the type of biological sample indicate Aspergillus carriage, colonization or infection in a patient? Highly accurate routine filamentous fungi identification is central to enhance the understanding of these previously unknown Aspergillus species, with a vital impact on further improved patient care. Copyright © 2016 European Society of Clinical Microbiology and
Calibration Errors in Interferometric Radio Polarimetry
Hales, Christopher A.
Residual calibration errors are difficult to predict in interferometric radio polarimetry because they depend on the observational calibration strategy employed, encompassing the Stokes vector of the calibrator and parallactic angle coverage. This work presents analytic derivations and simulations that enable examination of residual on-axis instrumental leakage and position-angle errors for a suite of calibration strategies. The focus is on arrays comprising alt-azimuth antennas with common feeds over which parallactic angle is approximately uniform. The results indicate that calibration schemes requiring parallactic angle coverage in the linear feed basis (e.g., the Atacama Large Millimeter/submillimeter Array) need only observe over 30°, beyond which no significant improvements in calibration accuracy are obtained. In the circular feed basis (e.g., the Very Large Array above 1 GHz), 30° is also appropriate when the Stokes vector of the leakage calibrator is known a priori, but this rises to 90° when the Stokes vector is unknown. These findings illustrate and quantify concepts that were previously obscure rules of thumb.
International Nuclear Information System (INIS)
Rydberg, J.
After the introduction of a law prohibiting the start-up of any new nuclear power plant until the utility had shown that the waste produced by the plant could be taken care of in an absolutely safe way, the Swedish nuclear utilities in December 1976 embarked on the Nuclear Fuel Safety Project, which in November 1977 presented a first report, Handling of Spent Nuclear Fuel and Final Storage of Vitrified Waste (KBS-I), and in November 1978 a second report, Handling and Final Storage of Unreprocessed Spent Nuclear Fuel (KBS II). These summary reports were supported by 120 technical reports prepared by 450 experts. The project engaged 70 private and governmental institutions at a total cost of US $15 million. The KBS-I and KBS-II reports are summarized in this document, as are also continued waste research efforts carried out by KBS, SKBF, PRAV, ASEA and other Swedish organizations. The KBS reports describe all steps (except reprocessing) in handling chain from removal from a reactor of spent fuel elements until their radioactive waste products are finally disposed of, in canisters, in an underground granite depository. The KBS concept relies on engineered multibarrier systems in combination with final storage in thoroughly investigated stable geologic formations. This report also briefly describes other activities carried out by the nuclear industry, namely, the construction of a central storage facility for spent fuel elements (to be in operation by 1985), a repository for reactor waste (to be in operation by 1988), and an intermediate storage facility for vitrified high-level waste (to be in operation by 1990). The R and D activities are updated to September 1981
Worldwide effort against smoking.
The 39th World Health Assembly, which met in May 1986, recognized the escalating health problem of smoking-related diseases and affirmed that tobacco smoking and its use in other forms are incompatible with the attainment of "Health for All by the Year 2000." If properly implemented, antismoking campaigns can decrease the prevalence of smoking. Nations as a whole must work toward changing smoking habits, and governments must support these efforts by officially stating their stand against smoking. Over 60 countries have introduced legislation affecting smoking. The variety of policies range from adopting a health education program designed to increase peoples' awareness of its dangers to increasing taxes to deter smoking by increasing tobacco prices. Each country must adopt an antismoking campaign which works most effectively within the cultural parameters of the society. Other smoking policies include: printed warnings on cigarette packages; health messages via radio, television, mobile teams, pamphlets, health workers, clinic walls, and newspapers; prohibition of smoking in public areas and transportation; prohibition of all advertisement of cigarettes and tobacco; and the establishment of upper limits of tar and nicotine content in cigarettes. The tobacco industry spends about $2000 million annually on worldwide advertising. According to the World Health Organization (WHO), controlling this overabundance of tobacco advertisements is a major priority in preventing the spread of smoking. Cigarette and tobacco advertising can be controlled to varying degrees, e.g., over a dozen countries have enacted a total ban on advertising on television or radio, a mandatory health warning must accompany advertisements in other countries, and tobacco companies often are prohibited from sponsoring sports events. Imposing a substantial tax on cigarettes is one of the most effective means to deter smoking. However, raising taxes and banning advertisements is not enough because
Calibrating the neutron moisture meter: Precision and economy
International Nuclear Information System (INIS)
Akhter, J.; Waheed, R.A.; Hignett, C.T.; Greacen, E.L.
Established laboratory and field calibration procedures for the neutron moisture meter are demonstrated on a uniform soil and alternative, low cost procedures on a duplex, less uniform soil. The effect of field variability on the calibration methodology is discussed with the aim of optimising calibration reliability at minimal cost. The difference between calibration for a soil material, or for a field (a range of soil materials) is considered. In particular, calibration for the estimation of water content change is shown to be a different problem from calibration for the estimation of water content in a variable field. Techniques aimed at detecting field variability problems during calibration are suggested, and methods for optimising the results for the intended use of the instrument are outlined. Pairing of calibration tubes, alternative methods of analysis of calibration data, and use of other information from the field to measure its variability, can improve the precision of calibration procedures to the point where minimal calibration effort, with careful analysis, can provide reliable results. (author)
Compact radiometric microwave calibrator
International Nuclear Information System (INIS)
Fixsen, D. J.; Wollack, E. J.; Kogut, A.; Limon, M.; Mirel, P.; Singal, J.; Fixsen, S. M.
The calibration methods for the ARCADE II instrument are described and the accuracy estimated. The Steelcast coated aluminum cones which comprise the calibrator have a low reflection while maintaining 94% of the absorber volume within 5 mK of the base temperature (modeled). The calibrator demonstrates an absorber with the active part less than one wavelength thick and only marginally larger than the mouth of the largest horn and yet black (less than -40 dB or 0.01% reflection) over five octaves in frequency
DEFF Research Database (Denmark)
Fernandez Garcia, Sergio; Villanueva, Héctor
This report presents the result of the lidar to lidar calibration performed for ground-based lidar. Calibration is here understood as the establishment of a relation between the reference lidar wind speed measurements with measurement uncertainties provided by measurement standard and corresponding...... lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from the reference lidar measurements are given for information only....
The Effort Paradox: Effort Is Both Costly and Valued.
Inzlicht, Michael; Shenhav, Amitai; Olivola, Christopher Y
According to prominent models in cognitive psychology, neuroscience, and economics, effort (be it physical or mental) is costly: when given a choice, humans and non-human animals alike tend to avoid effort. Here, we suggest that the opposite is also true and review extensive evidence that effort can also add value. Not only can the same outcomes be more rewarding if we apply more (not less) effort, sometimes we select options precisely because they require effort. Given the increasing recognition of effort's role in motivation, cognitive control, and value-based decision-making, considering this neglected side of effort will not only improve formal computational models, but also provide clues about how to promote sustained mental effort across time. Copyright © 2018 Elsevier Ltd. All rights reserved.
SU-E-T-749: Thorough Calibration of MOSFET Dosimeters
International Nuclear Information System (INIS)
Plenkovich, D; Thomas, J
Purpose: To improve the accuracy of the MOSFET calibration procedure by performing the measurement several times and calculating the average value of the calibration factor for various photon and electron energies. Methods: The output of three photon and six electron beams of Varian Trilogy linear accelerator SN 5878 was calibrated. Five reinforced standard sensitivity MOSFET dosimeters were placed in the calibration jig and connected to the Reader Module. As the backscatter material was used 7 cm of Virtual Water. The MOSFET dosimeters were covered with 1.5 cm thick bolus for the regular and SRS 6 MV beams, 3 cm bolus for 15 MV beam, 1.5 cm bolus for 6 MeV electron beam, and 2 cm bolus for the electron energies of 9, 12, 15, 18, and 22 MeV. The dosimeters were exposed to 100 MU, and the calibration factor was determined using the mobileMOSFET software. To improve the accuracy of calibration, this procedure was repeated ten times and the calibration factors were averaged. Results: As the number of calibrations was increasing the variability of calibration factors of different dosimeters was decreasing. After ten calibrations, the calibration factors for all five dosimeters were within 1% of one another for all energies, except 6 MV SRS photons and 6 MeV electrons, for which the variability was 2%. Conclusions: The described process results in calibration factors which are almost independent of modality or energy. Once calibrated, the dosimeters may be used for in-vivo dosimetry or for daily verification of the beam output. Measurement of the radiation dose under bolus and scatter to the eye are examples of frequent use of calibrated MOSFET dosimeters. The calibration factor determined for full build-up is used under these circumstances. To the best of our knowledge, such thorough procedure for calibrating MOSFET dosimeters has not been reported previously. Best Medical Canada provided MOSFET dosimeters for this project
Federal Laboratory Consortium — This facility is for low altitude subsonic altimeter system calibrations of air vehicles. Mission is a direct support of the AFFTC mission. Postflight data merge is...
U.S. Environmental Protection Agency — an UV calibration curve for SRHA quantitation. This dataset is associated with the following publication: Chang, X., and D. Bouchard. Surfactant-Wrapped Multiwalled...
International Nuclear Information System (INIS)
Zhang Bingyun; Li Xiaonan; Zhu Kejun; Zhang Jiawen; Gong Mingyu
We constructed BES (Beijing Spectrometer) online calibration system to ensure the coherence of readout electronic channels due to huge data volume in high energy physics experiment. This paper describes the structure of hardware and software, and its characteristic and function
International Nuclear Information System (INIS)
Ahlers, C.F.; Liu, H.H.
The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the AMR Development Plan for U0035 Calibrated Properties Model REV00 (CRWMS M and O 1999c). These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions
International Nuclear Information System (INIS)
Ahlers, C.; Liu, H.
The purpose of this Analysis/Model Report (AMR) is to document the Calibrated Properties Model that provides calibrated parameter sets for unsaturated zone (UZ) flow and transport process models for the Yucca Mountain Site Characterization Project (YMP). This work was performed in accordance with the ''AMR Development Plan for U0035 Calibrated Properties Model REV00. These calibrated property sets include matrix and fracture parameters for the UZ Flow and Transport Model (UZ Model), drift seepage models, drift-scale and mountain-scale coupled-processes models, and Total System Performance Assessment (TSPA) models as well as Performance Assessment (PA) and other participating national laboratories and government agencies. These process models provide the necessary framework to test conceptual hypotheses of flow and transport at different scales and predict flow and transport behavior under a variety of climatic and thermal-loading conditions
Directory of Open Access Journals (Sweden)
Patterson E.
Full Text Available The results are presented using the procedure outlined by the Standardisation Project for Optical Techniques of Strain measurement to calibrate a digital image correlation system. The process involves comparing the experimental data obtained with the optical measurement system to the theoretical values for a specially designed specimen. The standard states the criteria which must be met in order to achieve successful calibration, in addition to quantifying the measurement uncertainty in the system. The system was evaluated at three different displacement load levels, generating strain ranges from 289 µstrain to 2110 µstrain. At the 289 µstrain range, the calibration uncertainty was found to be 14.1 µstrain, and at the 2110 µstrain range it was found to be 28.9 µstrain. This calibration procedure was performed without painting a speckle pattern on the surface of the metal. Instead, the specimen surface was prepared using different grades of grit paper to produce the desired texture.
Calibration of thermoluminiscent materials
International Nuclear Information System (INIS)
Bos, A.J.J.
In this report the relation between exposure and absorbed radiation dose in various materials is represented, on the base of recent data. With the help of this a calibration procedure for thermoluminescent materials, adapted to the IRI radiation standard is still the exposure in rontgen. In switching to the air kerma standard the calibration procedure will have to be adapted. (author). 6 refs.; 4 tabs
Energy Technology Data Exchange (ETDEWEB)
Courtney, M.
Nacelle mounted, forward looking wind lidars are beginning to be used to provide reference wind speed measurements for the power performance testing of wind turbines. In such applications, a formal calibration procedure with a corresponding uncertainty assessment will be necessary. This report presents four concepts for performing such a nacelle lidar calibration. Of the four methods, two are found to be immediately relevant and are pursued in some detail. The first of these is a line of sight calibration method in which both lines of sight (for a two beam lidar) are individually calibrated by accurately aligning the beam to pass close to a reference wind speed sensor. A testing procedure is presented, reporting requirements outlined and the uncertainty of the method analysed. It is seen that the main limitation of the line of sight calibration method is the time required to obtain a representative distribution of radial wind speeds. An alternative method is to place the nacelle lidar on the ground and incline the beams upwards to bisect a mast equipped with reference instrumentation at a known height and range. This method will be easier and faster to implement and execute but the beam inclination introduces extra uncertainties. A procedure for conducting such a calibration is presented and initial indications of the uncertainties given. A discussion of the merits and weaknesses of the two methods is given together with some proposals for the next important steps to be taken in this work. (Author)
NICMOS Cycles 13 and 14 Calibration Plans
Arribas, Santiago; Bergeron, Eddie; de Jong, Roeof; Malhotra, Sangeeta; Mobasher, Bahram; Noll, Keith; Schultz, Al; Wiklind, Tommy; Xu, Chun
This document summarizes the NICMOS Calibration Plans for Cycles 13 and 14. These plans complement the SMOV3b, the Cycle 10 (interim), and the Cycles 11 and 12 (regular) calibration programs executed after the installation of the NICMOS Cooling System (NCS).. These previous programs have shown that the instrument is very stable, which has motivated a further reduction in the frequency of the monitoring programs for Cycle 13. In addition, for Cycle 14 some of these programs were slightly modified to account for 2 Gyro HST operations. The special calibrations on Cycle 13 were focussed on a follow up of the spectroscopic recalibration initiated in Cycle 12. This program led to the discovery of a possible count rate non-linearity, which has triggered a special program for Cycle 13 and a number of subsequent tests and calibrations during Cycle 14. At the time of writing this is a very active area of research. We also briefly comment on other calibrations defined to address other specific issues like: the autoreset test, the SPAR sequences tests, and the low-frequency flat residual for NIC1. The calibration programs for the 2-Gyro campaigns are not included here, since they have been described somewhere else. Further details and updates on specific programs can be found via the NICMOS web site.
Evolution of Altimetry Calibration and Future Challenges
Fu, Lee-Lueng; Haines, Bruce J.
Over the past 20 years, altimetry calibration has evolved from an engineering-oriented exercise to a multidisciplinary endeavor driving the state of the art. This evolution has been spurred by the developing promise of altimetry to capture the large-scale, but small-amplitude, changes of the ocean surface containing the expression of climate change. The scope of altimeter calibration/validation programs has expanded commensurately. Early efforts focused on determining a constant range bias and verifying basic compliance of the data products with mission requirements. Contemporary investigations capture, with increasing accuracies, the spatial and temporal characteristics of errors in all elements of the measurement system. Dedicated calibration sites still provide the fundamental service of estimating absolute bias, but also enable long-term monitoring of the sea-surface height and constituent measurements. The use of a network of island and coastal tide gauges has provided the best perspective on the measurement stability, and revealed temporal variations of altimeter measurement system drift. The cross-calibration between successive missions provided fundamentally new information on the performance of altimetry systems. Spatially and temporally correlated errors pose challenges for future missions, underscoring the importance of cross-calibration of new measurements against the established record.
Calibration Under Uncertainty.
Energy Technology Data Exchange (ETDEWEB)
Swiler, Laura Painton; Trucano, Timothy Guy
This report is a white paper summarizing the literature and different approaches to the problem of calibrating computer model parameters in the face of model uncertainty. Model calibration is often formulated as finding the parameters that minimize the squared difference between the model-computed data (the predicted data) and the actual experimental data. This approach does not allow for explicit treatment of uncertainty or error in the model itself: the model is considered the %22true%22 deterministic representation of reality. While this approach does have utility, it is far from an accurate mathematical treatment of the true model calibration problem in which both the computed data and experimental data have error bars. This year, we examined methods to perform calibration accounting for the error in both the computer model and the data, as well as improving our understanding of its meaning for model predictability. We call this approach Calibration under Uncertainty (CUU). This talk presents our current thinking on CUU. We outline some current approaches in the literature, and discuss the Bayesian approach to CUU in detail.
Calibration of EFOSC2 Broadband Linear Imaging Polarimetry
Wiersema, K.; Higgins, A. B.; Covino, S.; Starling, R. L. C.
The European Southern Observatory Faint Object Spectrograph and Camera v2 is one of the workhorse instruments on ESO's New Technology Telescope, and is one of the most popular instruments at La Silla observatory. It is mounted at a Nasmyth focus, and therefore exhibits strong, wavelength and pointing-direction-dependent instrumental polarisation. In this document, we describe our efforts to calibrate the broadband imaging polarimetry mode, and provide a calibration for broadband B, V, and R filters to a level that satisfies most use cases (i.e. polarimetric calibration uncertainty 0.1%). We make our calibration codes public. This calibration effort can be used to enhance the yield of future polarimetric programmes with the European Southern Observatory Faint Object Spectrograph and Camera v2, by allowing good calibration with a greatly reduced number of standard star observations. Similarly, our calibration model can be combined with archival calibration observations to post-process data taken in past years, to form the European Southern Observatory Faint Object Spectrograph and Camera v2 legacy archive with substantial scientific potential.
International Nuclear Information System (INIS)
Bird, A.J.; Barlow, E.J.; Tikkanen, T.; Bazzano, A.; Del Santo, M.; Ubertini, P.; Blondel, C.; Laurent, P.; Lebrun, F.; Di Cocco, G.; Malaguti, E.; Gabriele, M.; La Rosa, G.; Segreto, A.; Quadrini, E.; Volkmer, R.
We present an overview of results obtained from IBIS ground calibrations. The spectral and spatial characteristics of the detector planes and surrounding passive materials have been determined through a series of calibration campaigns. Measurements of pixel gain, energy resolution, detection uniformity, efficiency and imaging capability are presented. The key results obtained from the ground calibration have been: - optimization of the instrument tunable parameters, - determination of energy linearity for all detection modes, - determination of energy resolution as a function of energy through the range 20 keV - 3 MeV, - demonstration of imaging capability in each mode, - measurement of intrinsic detector non-uniformity and understanding of the effects of passive materials surrounding the detector plane, and - discovery (and closure) of various leakage paths through the passive shielding system
Gamma counter calibration system
International Nuclear Information System (INIS)
A method and apparatus are described for the calibration of a gamma radiation measurement instrument to be used over any of a number of different absolute energy ranges. The method includes the steps of adjusting the overall signal gain associated with pulses which are derived from detected gamma rays, until the instrument is calibrated for a particular absolute energy range; then storing parameter settings corresponding to the adjusted overall signal gain, and repeating the process for other desired absolute energy ranges. The stored settings can be subsequently retrieved and reapplied so that test measurements can be made using a selected one of the absolute energy ranges. Means are provided for adjusting the overall signal gain and a specific technique is disclosed for making coarse, then fine adjustments to the signal gain, for rapid convergence of the required calibration settings. (C.F.)
Individual dosimetry and calibration
International Nuclear Information System (INIS)
Hoefert, M.; Nielsen, M.
In 1995 both the Individual Dosimetry and Calibration Sections worked under the condition of a status quo and concentrated fully on the routine part of their work. Nevertheless, the machine for printing the bar code which will be glued onto the film holder and hence identify the people when entering into high radiation areas was put into operation and most of the holders were equipped with the new identification. As far as the Calibration Section is concerned the project of the new source control system that is realized by the Technical Support Section was somewhat accelerated
Radiation Calibration Measurements
International Nuclear Information System (INIS)
Omondi, C.
KEBS Radiation Dosimetry mandate are: Custodian of Kenya Standards on Ionizing radiation, Ensure traceability to International System (SI ) and Calibration radiation equipment. RAF 8/040 on Radioisotope applications for troubleshooting and optimizing industrial process established Radiotracer Laboratory objective is to introduce and implement radiotracer technique for problem solving of industrial challenges. Gamma ray scanning technique applied is to Locate blockages, Locate liquid in vapor lines, Locate areas of lost refractory or lining in a pipe and Measure flowing densities. Equipment used for diagnostic and radiation protection must be calibrated to ensure Accuracy and Traceability
DEFF Research Database (Denmark)
Gómez Arranz, Paula; Courtney, Michael
This report describes the tests carried out on a scanning lidar at the DTU Test Station for large wind turbines, Høvsøre. The tests were divided in two parts. In the first part, the purpose was to obtain wind speed calibrations at two heights against two cup anemometers mounted on a mast. Additio......This report describes the tests carried out on a scanning lidar at the DTU Test Station for large wind turbines, Høvsøre. The tests were divided in two parts. In the first part, the purpose was to obtain wind speed calibrations at two heights against two cup anemometers mounted on a mast...
Cognitive effort: A neuroeconomic approach
Braver, Todd S.
Cognitive effort has been implicated in numerous theories regarding normal and aberrant behavior and the physiological response to engagement with demanding tasks. Yet, despite broad interest, no unifying, operational definition of cognitive effort itself has been proposed. Here, we argue that the most intuitive and epistemologically valuable treatment is in terms of effort-based decision-making, and advocate a neuroeconomics-focused research strategy. We first outline psychological and neuroscientific theories of cognitive effort. Then we describe the benefits of a neuroeconomic research strategy, highlighting how it affords greater inferential traction than do traditional markers of cognitive effort, including self-reports and physiologic markers of autonomic arousal. Finally, we sketch a future series of studies that can leverage the full potential of the neuroeconomic approach toward understanding the cognitive and neural mechanisms that give rise to phenomenal, subjective cognitive effort. PMID:25673005
CERN. Geneva
My talk will be covering my work as a whole over the course of the semester. The focus will be on using energy flow calibration in ECAL to check the precision of the corrections made by the light monitoring system used to account for transparency loss within ECAL crystals due to radiation damage over time.
Calibration with Absolute Shrinkage
DEFF Research Database (Denmark)
Øjelund, Henrik; Madsen, Henrik; Thyregod, Poul
In this paper, penalized regression using the L-1 norm on the estimated parameters is proposed for chemometric je calibration. The algorithm is of the lasso type, introduced by Tibshirani in 1996 as a linear regression method with bound on the absolute length of the parameters, but a modification...
Calibration bench of flowmeters
International Nuclear Information System (INIS)
Bremond, J.; Da Costa, D.; Calvet, A.; Vieuxmaire, C.
This equipment is devoted to the comparison of signals from two turbines installed in the Cabri experimental loop. The signal is compared to the standard turbine. The characteristics and the performance of the calibration bench are presented. (A.L.B.)
Calibration of farmer dosemeters
International Nuclear Information System (INIS)
Ahmad, S.S.; Anwar, K.; Arshed, W.; Mubarak, M.A.; Orfi, S.D.
The Farmer Dosemeters of Atomic Energy Medical Centre (AEMC) Jamshoro were calibrated in the Secondary Standard Dosimetry Laboratory (SSDL) at PINSTECH, using the NPL Secondary Standard Therapy level X-ray exposure meter. The results are presented in this report. (authors)
Physiotherapy ultrasound calibrations
International Nuclear Information System (INIS)
Gledhill, M.
Calibration of physiotherapy ultrasound equipment has long been a problem. Numerous surveys around the world over the past 20 years have all found that only a low percentage of the units tested had an output within 30% of that indicatd. In New Zealand, a survey carried out by the NRL in 1985 found that only 24% had an output, at the maximum setting, within + or - 20% of that indicated. The present performance Standard for new equipment (NZS 3200.2.5:1992) requires that the measured output should not deviate from that indicated by more than + or - 30 %. This may be tightened to + or - 20% in the next few years. Any calibration is only as good as the calibration equipment. Some force balances can be tested with small weights to simulate the force exerted by an ultrasound beam, but with others this is not possible. For such balances, testing may only be feasible with a calibrated source which could be used like a transfer standard. (author). 4 refs., 3 figs
NVLAP calibration laboratory program
Energy Technology Data Exchange (ETDEWEB)
Cigler, J.L.
This paper presents an overview of the progress up to April 1993 in the development of the Calibration Laboratories Accreditation Program within the framework of the National Voluntary Laboratory Accreditation Program (NVLAP) at the National Institute of Standards and Technology (NIST).
NVLAP calibration laboratory program
International Nuclear Information System (INIS)
Cigler, J.L.
This paper presents an overview of the progress up to April 1993 in the development of the Calibration Laboratories Accreditation Program within the framework of the National Voluntary Laboratory Accreditation Program (NVLAP) at the National Institute of Standards and Technology (NIST)
International Nuclear Information System (INIS)
Rosauer, P.J.; Flaherty, J.J.
This invention is in the field of gamma ray inspection devices for tubular products and the like employing an improved calibrating block which prevents the sensing system from being overloaded when no tubular product is present, and also provides the operator with a means for visually detecting the presence of wall thicknesses which are less than a required minimum. (author)
Carbon resistor pressure gauge calibration at low stresses
International Nuclear Information System (INIS)
Cunningham, Bruce; Vandersall, Kevin S.; Niles, Angela M.; Greenwood, Daniel W.; Garcia, Frank; Forbes, Jerry W.; Wilson, William H.
The 470 Ohm carbon resistor gauge has been used in the stress range up to 4-5 GPa for highly heterogeneous materials and/or divergent flow experiments. The attractiveness of the gauge is its rugged nature, simple construction, low cost, reproducibility, and survivability in dynamic events. Gauge drawbacks are the long time response to pressure equilibration and gauge resistance hysteresis. In the regime below 0.4 GPa, gauge calibration has been extrapolated. Because of the need for calibration data within this low stress regime, calibration experiments were performed using a split-Hopkinson bar, drop tower apparatus, and gas pressure chamber. Since the performance of the gauge at elevated temperatures is a concern, the change in resistance due to heating at atmospheric pressure was also investigated. Details of the various calibration arrangements and the results are discussed and compared to a calibration curve fit to previously published calibration data
Directory of Open Access Journals (Sweden)
S. Lachérade
Full Text Available In-flight calibration of space sensors once in orbit is a decisive step to be able to fulfil the mission objectives. This article presents the methods of the in-flight absolute calibration processed during the commissioning phase. Four In-flight calibration methods are used: absolute calibration, cross-calibration with reference sensors such as PARASOL or MERIS, multi-temporal monitoring and inter-bands calibration. These algorithms are based on acquisitions over natural targets such as African deserts, Antarctic sites, La Crau (Automatic calibration station and Oceans (Calibration over molecular scattering or also new extra-terrestrial sites such as the Moon and selected stars. After an overview of the instrument and a description of the calibration sites, it is pointed out how each method is able to address one or several aspects of the calibration. We focus on how these methods complete each other in their operational use, and how they help building a coherent set of information that addresses all aspects of in-orbit calibration. Finally, we present the perspectives that the high level of agility of PLEIADES offers for the improvement of its calibration and a better characterization of the calibration sites.
Energy Technology Data Exchange (ETDEWEB)
John F. Schabron; Joseph F. Rovani; Susan S. Sorini
The Clean Air Mercury Rule (CAMR) which was published in the Federal Register on May 18, 2005, requires that calibration of mercury continuous emissions monitors (CEMs) be performed with NIST-traceable standards. Western Research Institute (WRI) is working closely with the Electric Power Research Institute (EPRI), the National Institute of Standards and Technology (NIST), and the Environmental Protection Agency (EPA) to facilitate the development of the experimental criteria for a NIST traceability protocol for dynamic elemental mercury vapor generators. The traceability protocol will be written by EPA. Traceability will be based on the actual analysis of the output of each calibration unit at several concentration levels ranging from about 2-40 ug/m{sup 3}, and this analysis will be directly traceable to analyses by NIST using isotope dilution inductively coupled plasma/mass spectrometry (ID ICP/MS) through a chain of analyses linking the calibration unit in the power plant to the NIST ID ICP/MS. Prior to this project, NIST did not provide a recommended mercury vapor pressure equation or list mercury vapor pressure in its vapor pressure database. The NIST Physical and Chemical Properties Division in Boulder, Colorado was subcontracted under this project to study the issue in detail and to recommend a mercury vapor pressure equation that the vendors of mercury vapor pressure calibration units can use to calculate the elemental mercury vapor concentration in an equilibrium chamber at a particular temperature. As part of this study, a preliminary evaluation of calibration units from five vendors was made. The work was performed by NIST in Gaithersburg, MD and Joe Rovani from WRI who traveled to NIST as a Visiting Scientist.
Rapid fish stock depletion in previously unexploited seamounts: the ...
African Journals Online (AJOL)
Rapid fish stock depletion in previously unexploited seamounts: the case of Beryx splendens from the Sierra Leone Rise (Gulf of Guinea) ... A spectral analysis and red-noise spectra procedure (REDFIT) algorithm was used to identify the red-noise spectrum from the gaps in the observed time-series of catch per unit effort by ...
Multidisciplinary Efforts Driving Translational Theranostics
Hu, Tony Y.
This themed issue summarizes significant efforts aimed at using "biological language" to discern between "friends" and "foes" in the context of theranostics for true clinical application. It is expected that the success of theranostics depends on multidisciplinary efforts, combined to expedite our understanding of host responses to "customized" theranostic agents and formulating individualized therapies. PMID:25285169
Learning Environment and Student Effort
Hopland, Arnt O.; Nyhus, Ole Henning
Purpose: The purpose of this paper is to explore the relationship between satisfaction with learning environment and student effort, both in class and with homework assignments. Design/methodology/approach: The authors use data from a nationwide and compulsory survey to analyze the relationship between learning environment and student effort. The…
Field calibration of cup anemometers
DEFF Research Database (Denmark)
Schmidt Paulsen, Uwe; Mortensen, Niels Gylling; Hansen, Jens Carsten
A field calibration method and results are described along with the experience gained with the method. The cup anemometers to be calibrated are mounted in a row on a 10-m high rig and calibrated in the free wind against a reference cup anemometer. The method has been reported [1] to improve...... the statistical bias on the data relative to calibrations carried out in a wind tunnel. The methodology is sufficiently accurate for calibration of cup anemometers used for wind resource assessments and provides a simple, reliable and cost-effective solution to cup anemometer calibration, especially suited...
Respiratory effort from the photoplethysmogram.
Addison, Paul S
The potential for a simple, non-invasive measure of respiratory effort based on the pulse oximeter signal - the photoplethysmogram or 'pleth' - was investigated in a pilot study. Several parameters were developed based on a variety of manifestations of respiratory effort in the signal, including modulation changes in amplitude, baseline, frequency and pulse transit times, as well as distinct baseline signal shifts. Thirteen candidate parameters were investigated using data from healthy volunteers. Each volunteer underwent a series of controlled respiratory effort maneuvers at various set flow resistances and respiratory rates. Six oximeter probes were tested at various body sites. In all, over three thousand pleth-based effort-airway pressure (EP) curves were generated across the various airway constrictions, respiratory efforts, respiratory rates, subjects, probe sites, and the candidate parameters considered. Regression analysis was performed to determine the existence of positive monotonic relationships between the respiratory effort parameters and resulting airway pressures. Six of the candidate parameters investigated exhibited a distinct positive relationship (poximeter probe and an ECG (P2E-Effort) and the other using two pulse oximeter probes placed at different peripheral body sites (P2-Effort); and baseline shifts in heart rate, (BL-HR-Effort). In conclusion, a clear monotonic relationship was found between several pleth-based parameters and imposed respiratory loadings at the mouth across a range of respiratory rates and flow constrictions. The results suggest that the pleth may provide a measure of changing upper airway dynamics indicative of the effort to breathe. Copyright © 2017 The Author. Published by Elsevier Ltd.. All rights reserved.
Calibration of a Modified Californium Shuffler
International Nuclear Information System (INIS)
Sadowski, E.T.; Armstrong, F.; Oldham, R.; Ceo, R.; Williams, N.
A californium shuffler originally designed to assay hollow cylindrical pieces of UA1 has been modified to assay solid cylinders. Calibration standards were characterized via chemical analysis of the molten UA1 taken during casting of the standards. The melt samples yielded much more reliable characterization data than drill samples taken from standards after the standards had solidified. By normalizing one well-characterized calibration curve to several standards at different enrichments, a relatively small number of standards was required to develop an enrichment-dependent calibration. The precision of this shuffler is 0.65%, and the typical random and systematic uncertainties are 0.53% and 0.73%, respectively, for a six minute assay of an ingot containing approximately 700 grams of 235 U. This paper will discuss (1) the discrepancies encountered when UA1 standards were characterized via melt samples versus drill samples, (2) a calibration methodology employing a small number of standards, and (3) a comparison of results from a previously unused shuffler with an existing shuffler. A small number of UA1 standards have been characterized using samples from the homogeneous molten state and have yielded enrichment-dependent and enrichment-independent calibration curves on two different shufflers
Effort rights-based management
DEFF Research Database (Denmark)
Squires, Dale; Maunder, Mark; Allen, Robin
Effort rights-based fisheries management (RBM) is less widely used than catch rights, whether for groups or individuals. Because RBM on catch or effort necessarily requires a total allowable catch (TAC) or total allowable effort (TAE), RBM is discussed in conjunction with issues in assessing fish...... populations and providing TACs or TAEs. Both approaches have advantages and disadvantages, and there are trade-offs between the two approaches. In a narrow economic sense, catch rights are superior because of the type of incentives created, but once the costs of research to improve stock assessments...
MAVEN SEP Calibrated Data Bundle
National Aeronautics and Space Administration — The maven.sep.calibrated Level 2 Science Data Bundle contains fully calibrated SEP data, as well as the raw count data from which they are derived, and ancillary...
Ultrasonic calibration assembly
International Nuclear Information System (INIS)
Ultrasonic transducers for in-service inspection of nuclear reactor vessels have several problems associated with them which this invention seeks to overcome. The first is that of calibration or referencing a zero start point for the vertical axis of transducer movement to locate a weld defect. The second is that of verifying the positioning (vertically or at a predetermined angle). Thirdly there is the problem of ascertaining the speed per unit distance in the operating medium of the transducer beam prior to the actual inspection. The apparatus described is a calibration assembly which includes a fixed, generally spherical body having a surface for reflecting an ultrasonic beam from one of the transducers which can be moved until the reflection from the spherical body is the highest amplitude return signal indicating radial alignment from the body. (U.K.)
Travelling gradient thermocouple calibration
International Nuclear Information System (INIS)
Broomfield, G.H.
A short discussion of the origins of the thermocouple EMF is used to re-introduce the idea that the Peltier and Thompson effects are indistinguishable from one another. Thermocouples may be viewed as devices which generate an EMF at junctions or as integrators of EMF's developed in thermal gradients. The thermal gradient view is considered the more appropriate, because of its better accord with theory and behaviour, the correct approach to calibration, and investigation of service effects is immediately obvious. Inhomogeneities arise in thermocouples during manufacture and in service. The results of travelling gradient measurements are used to show that such effects are revealed with a resolution which depends on the length of the gradient although they may be masked during simple immersion calibration. Proposed tests on thermocouples irradiated in a nuclear reactor are discussed
Mesoscale hybrid calibration artifact
Tran, Hy D.; Claudet, Andre A.; Oliver, Andrew D.
A mesoscale calibration artifact, also called a hybrid artifact, suitable for hybrid dimensional measurement and the method for make the artifact. The hybrid artifact has structural characteristics that make it suitable for dimensional measurement in both vision-based systems and touch-probe-based systems. The hybrid artifact employs the intersection of bulk-micromachined planes to fabricate edges that are sharp to the nanometer level and intersecting planes with crystal-lattice-defined angles.
Calibration of germanium detectors
International Nuclear Information System (INIS)
Bjurman, B.; Erlandsson, B.
This paper describes problems concerning the calibration of germanium detectors for the measurement of gamma-radiation from environmental samples. It also contains a brief description of some ways of reducing the uncertainties concerning the activity determination. These uncertainties have many sources, such as counting statistics, full energy peak efficiency determination, density correction and radionuclide specific-coincidence effects, when environmental samples are investigated at close source-to-detector distances
Lorefice, Salvatore; Malengo, Andrea
After a brief description of the different methods employed in periodic calibration of hydrometers used in most cases to measure the density of liquids in the range between 500 kg m-3 and 2000 kg m-3, particular emphasis is given to the multipoint procedure based on hydrostatic weighing, known as well as Cuckow's method. The features of the calibration apparatus and the procedure used at the INRiM (formerly IMGC-CNR) density laboratory have been considered to assess all relevant contributions involved in the calibration of different kinds of hydrometers. The uncertainty is strongly dependent on the kind of hydrometer; in particular, the results highlight the importance of the density of the reference buoyant liquid, the temperature of calibration and the skill of operator in the reading of the scale in the whole assessment of the uncertainty. It is also interesting to realize that for high-resolution hydrometers (division of 0.1 kg m-3), the uncertainty contribution of the density of the reference liquid is the main source of the total uncertainty, but its importance falls under about 50% for hydrometers with a division of 0.5 kg m-3 and becomes somewhat negligible for hydrometers with a division of 1 kg m-3, for which the reading uncertainty is the predominant part of the total uncertainty. At present the best INRiM result is obtained with commercially available hydrometers having a scale division of 0.1 kg m-3, for which the relative uncertainty is about 12 × 10-6.
Observation models in radiocarbon calibration
International Nuclear Information System (INIS)
Jones, M.D.; Nicholls, G.K.
The observation model underlying any calibration process dictates the precise mathematical details of the calibration calculations. Accordingly it is important that an appropriate observation model is used. Here this is illustrated with reference to the use of reservoir offsets where the standard calibration approach is based on a different model to that which the practitioners clearly believe is being applied. This sort of error can give rise to significantly erroneous calibration results. (author). 12 refs., 1 fig
Dosimetry and Calibration Section
International Nuclear Information System (INIS)
Otto, T.
The two tasks of the Dosimetry and Calibration Section at CERN are the Individual Dosimetry Service which assures the personal monitoring of about 5000 persons potentially exposed to ionizing radiation at CERN, and the Calibration Laboratory which verifies all the instruments and monitors. This equipment is used by the sections of the RP Group for assuring radiation protection around CERN's accelerators, and by the Environmental Section of TISTE. In addition, nearly 250 electronic and 300 quartz fibre dosimeters, employed in operational dosimetry, are calibrated at least once a year. The Individual Dosimetry Service uses an extended database (INDOS) which contains information about all the individual doses ever received at CERN. For most of 1997 it was operated without the support of a database administrator as the technician who had assured this work retired. The Software Support Section of TIS-TE took over the technical responsibility of the database, but in view of the many other tasks of this Section and the lack of personnel, only a few interventions for solving immediate problems were possible
Pandemic Influenza: Domestic Preparedness Efforts
National Research Council Canada - National Science Library
Lister, Sarah A
.... Though influenza pandemics occur with some regularity, and the United States has been involved in specific planning efforts since the early 1990s, the H5N1 situation has created a sense of urgency...
Effort Estimation in BPMS Migration
Drews, Christopher; Lantow, Birger
Usually Business Process Management Systems (BPMS) are highly integrated in the IT of organizations and are at the core of their business. Thus, migrating from one BPMS solution to another is not a common task. However, there are forces that are pushing organizations to perform this step, e.g. maintenance costs of legacy BPMS or the need for additional functionality. Before the actual migration, the risk and the effort must be evaluated. This work provides a framework for effort estimation re...
In-situ calibration of RTDs and pressure sensors in nuclear power plants
International Nuclear Information System (INIS)
Hashemian, H.M.
New techniques have been developed and validated for in-situ calibration of pressure transmitters as installed in nuclear power plants. These new techniques originate from a desire within the nuclear industry to monitor the calibration of pressure sensors during normal power operation by monitoring the DC output of the sensors for any significant draft and other anomalies. Currently, the calibration of pressure sensors is performed once every fuel cycle (18-24 months). The work involves significant manpower, radiation exposure to plant personnel, and potential damage to the plant equipment. In-situ calibration offers the potential to identify the sensors that need to be replaced or require calibration during normal plant operation, and reduce the calibration effort during outages to those sensors that need to be calibrated, as opposed to calibrating all the sensors
SCALA: In situ calibration for integral field spectrographs
Lombardo, S.; Küsters, D.; Kowalski, M.; Aldering, G.; Antilogus, P.; Bailey, S.; Baltay, C.; Barbary, K.; Baugh, D.; Bongard, S.; Boone, K.; Buton, C.; Chen, J.; Chotard, N.; Copin, Y.; Dixon, S.; Fagrelius, P.; Feindt, U.; Fouchez, D.; Gangler, E.; Hayden, B.; Hillebrandt, W.; Hoffmann, A.; Kim, A. G.; Leget, P.-F.; McKay, L.; Nordin, J.; Pain, R.; Pécontal, E.; Pereira, R.; Perlmutter, S.; Rabinowitz, D.; Reif, K.; Rigault, M.; Rubin, D.; Runge, K.; Saunders, C.; Smadja, G.; Suzuki, N.; Taubenberger, S.; Tao, C.; Thomas, R. C.; Nearby Supernova Factory
Aims: The scientific yield of current and future optical surveys is increasingly limited by systematic uncertainties in the flux calibration. This is the case for type Ia supernova (SN Ia) cosmology programs, where an improved calibration directly translates into improved cosmological constraints. Current methodology rests on models of stars. Here we aim to obtain flux calibration that is traceable to state-of-the-art detector-based calibration. Methods: We present the SNIFS Calibration Apparatus (SCALA), a color (relative) flux calibration system developed for the SuperNova integral field spectrograph (SNIFS), operating at the University of Hawaii 2.2 m (UH 88) telescope. Results: By comparing the color trend of the illumination generated by SCALA during two commissioning runs, and to previous laboratory measurements, we show that we can determine the light emitted by SCALA with a long-term repeatability better than 1%. We describe the calibration procedure necessary to control for system aging. We present measurements of the SNIFS throughput as estimated by SCALA observations. Conclusions: The SCALA calibration unit is now fully deployed at the UH 88 telescope, and with it color-calibration between 4000 Å and 9000 Å is stable at the percent level over a one-year baseline.
Calibration of triaxial fluxgate gradiometer
International Nuclear Information System (INIS)
Vcelak, Jan
The description of simple and fast calibration procedures used for double-probe triaxial fluxgate gradiometer is provided in this paper. The calibration procedure consists of three basic steps. In the first step both probes are calibrated independently in order to reach constant total field reading in every position. Both probes are numerically aligned in the second step in order that the gradient reading is zero in homogenous magnetic field. The third step consists of periodic drift calibration during measurement. The results and detailed description of each calibration step are presented and discussed in the paper. The gradiometer is finally verified during the detection of the metal object in the measuring grid
Primary calibration in acoustics metrology
International Nuclear Information System (INIS)
Milhomem, T A Bacelar; Soares, Z M Defilippo
SI unit in acoustics is realized by the reciprocity calibrations of laboratory standard microphones in pressure field, free field and diffuse field. Calibrations in pressure field and in free field are already consolidated and the Inmetro already done them. Calibration in diffuse field is not yet consolidated, however, some national metrology institutes, including Inmetro, are conducting researches on this subject. This paper presents the reciprocity calibration, the results of Inmetro in recent key comparisons and the research that is being developed for the implementation of reciprocity calibration in diffuse field
Dopamine, behavioral economics, and effort
Directory of Open Access Journals (Sweden)
John D Salamone
Full Text Available Abstract. There are numerous problems with the hypothesis that brain dopamine (DA systems, particularly in the nucleus accumbens, directly mediate the rewarding or primary motivational characteristics of natural stimuli such as food. Research and theory related to the functions of mesolimbic DA are undergoing a substantial conceptual restructuring, with the traditional emphasis on hedonia and primary reward yielding to other concepts and lines of inquiry. The present review is focused upon the involvement of nucleus accumbens DA in behavioral activation and effort-related processes. Viewed from the framework of behavioral economics, the effects of accumbens DA depletions and antagonism on food-reinforced behavior are highly dependent upon the work requirements of the instrumental task, and DA depleted rats are more sensitive to increases in response costs (i.e., ratio requirements. Moreover, interference with accumbens DA transmission exerts a powerful influence over effort-related choice behavior. Rats with accumbens DA depletions or antagonism reallocate their instrumental behavior away from food-reinforced tasks that have high response requirements, and instead these rats select a less-effortful type of food-seeking behavior. Nucleus accumbens DA and adenosine interact in the regulation of effort-related functions, and other brain structures (anterior cingulate cortex, amygdala, ventral pallidum also are involved. Studies of the brain systems regulating effort-based processes may have implications for understanding drug abuse, as well as energy-related disorders such as psychomotor slowing, fatigue or anergia in depression and other neurological disorders.
Calibration of the NPL secondary standard radionuclide calibrator for the new 10R Schott, Type 1+ vials
International Nuclear Information System (INIS)
Baker, M.
For many years, P6 vials have been used for the distribution of a wide range of diagnostic and therapeutic radioactive solutions. The activity measurements were performed in this geometry and, in time, the UK calibration system for nuclear medicine was based on this container as a standard. However, one major supplier of radiopharmaceuticals has replaced the P6 vial with the 10R Type 1+ Schott vial. As the dimensions of the new vial are different from those of the P6 vial and the responses of radionuclide calibrators are known to be container dependent, the need for re-calibration became apparent. Preliminary measurements made on some typical radionuclide calibrators for 125 I solution indicated a difference in response of about 10% between the two vials. The master ionisation chamber of the NPL secondary standard radionuclide calibrator has been re-calibrated and new calibration factors and volume correction factors for 10R Schott vials have been derived for the relevant medical radionuclides. The standard holder was also modified to accommodate the new larger vial. The complete list of factors and the method used to determine them is presented in this paper. The availability of these new factors will improve the quality of activity measurements in nuclear medicine, as calibration services can now be provided by NPL for the new container. These factors can also be employed for all commercial NPL secondary standard radionuclide calibrators (now known as the NPL-CRC and previously as the 671 or ISOCAL IV)
Maximum effort in the minimum-effort game
Czech Academy of Sciences Publication Activity Database
Engelmann, Dirk; Normann, H.-T.
Roč. 13, č. 3 (2010), s. 249-259 ISSN 1386-4157 Institutional research plan: CEZ:AV0Z70850503 Keywords : minimum-effort game * coordination game * experiments * social capital Subject RIV: AH - Economics Impact factor: 1.868, year: 2010
Wildi, F.; Chazelas, B.; Deline, A.; Sarajlic, M.; Sordet, M.
CHEOPS is an ESA Class S Mission aiming at the characterization of exoplanets through the precise measurement of their radius, using the transit method [1]. To achieve this goal, the payload is designed to be a high precision "absolute" photometer, looking at one star at a time. It will be able to cover la large fraction of the sky by repointing. Its launch is expected at the end of 2017 [2, this conference]. CHEOPS' main science is the measure of the transit of exoplanets of radius ranging from 1 to 6 Earth radii orbiting bright stars. The required photometric stability to reach this goal is of 20 ppm in 6 hours for a 9th magnitude star. The CHEOPS' only instrument is a Ritchey-Chretien style telescope with 300 mm effective aperture diameter, which provides a defocussed image of the target star on a single frame-transfer backside illuminated CCD detector cooled to -40°C and stabilized within 10 mK [2]. CHEOPS being in a LEO, it is equipped with a high performance baffle. The spacecraft platform provides a pointing stability of < 2 arcsec rms. This relatively modest pointing performance makes high quality flat-fielding necessary In the rest of this article we will refer to the only CHEOPS instrument simply as "CHEOP" Its behavior will be calibrated thoroughly on the ground and only a small subset of the calibrations can be redone in flight. The main focuses of the calibrations are the photonic gain stability and sensibility to the environment variations and the Flat field that has to be known at a precision better than 0.1%.
Directory of Open Access Journals (Sweden)
Sezar Gülbaz
Full Text Available The land development and increase in urbanization in a watershed affect water quantityand water quality. On one hand, urbanization provokes the adjustment of geomorphicstructure of the streams, ultimately raises peak flow rate which causes flood; on theother hand, it diminishes water quality which results in an increase in Total SuspendedSolid (TSS. Consequently, sediment accumulation in downstream of urban areas isobserved which is not preferred for longer life of dams. In order to overcome thesediment accumulation problem in dams, the amount of TSS in streams and inwatersheds should be taken under control. Low Impact Development (LID is a BestManagement Practice (BMP which may be used for this purpose. It is a land planningand engineering design method which is applied in managing storm water runoff inorder to reduce flooding as well as simultaneously improve water quality. LID includestechniques to predict suspended solid loads in surface runoff generated over imperviousurban surfaces. In this study, the impact of LID-BMPs on surface runoff and TSS isinvestigated by employing a calibrated hydrodynamic model for Sazlidere Watershedwhich is located in Istanbul, Turkey. For this purpose, a calibrated hydrodynamicmodel was developed by using Environmental Protection Agency Storm WaterManagement Model (EPA SWMM. For model calibration and validation, we set up arain gauge and a flow meter into the field and obtain rainfall and flow rate data. Andthen, we select several LID types such as retention basins, vegetative swales andpermeable pavement and we obtain their influence on peak flow rate and pollutantbuildup and washoff for TSS. Consequently, we observe the possible effects ofLID on surface runoff and TSS in Sazlidere Watershed.
Radionuclide calibrators performance evaluation
International Nuclear Information System (INIS)
Mora Ramirez, E.; Zeledon Fonseca, P.; Jimenez Cordero, M.
Radionuclide calibrators are used to estimate accurately activity prior to administration to a patient, so it is very important that this equipment meets its performance requirements. The purpose of this paper is to compare the commercially available 'Calicheck' (Calcorp. Inc), used to assess linearity, versus the well-known source decay method, and also to show our results after performing several recommended quality control tests. The parameters that we wanted to evaluate were carried on using the Capintec CRC-15R and CRC-15 β radionuclide calibrators. The evaluated tests were: high voltage, display, zero adjust, background, reproducibility, source constancy, accuracy, precision and linearity. The first six tests were evaluated on the daily practice, here we analyzed the 2007 recorded data; and the last three were evaluated once a year. During the daily evaluation both calibrators performance were satisfactory comparing with the manufacture's requirements. The accuracy test show result within the ± 10% allowed for a field instrument. Precision performance is within the ± 1 % allowed. On the other hand, the linearity test shows that using the source decay method the relative coefficient is 0.9998, for both equipment and using the Calicheck the relative coefficient is 0.997. However, looking the percentage of error, during the 'Calicheck' test, its range goes from 0.0 % up to -25.35%, and using the source decay method, the range goes from 0.0 % up to -31.05 %, taking into account both instruments. Checking the 'Calicheck' results we can see that the results varying randomly, but using the source decay method the percentage of error increase as the source activity decrease. We conclude that both devices meet its manufactures requirements, in the case of the linearity using the decay method, decreasing the activity source, increasing the percentage of error, this may happen because of the equipment age. (author)
Self-calibrating interferometer
International Nuclear Information System (INIS)
Nussmeier, T.A.
A self-calibrating interferometer is disclosed which forms therein a pair of Michelson interferometers with one beam length of each Michelson interferometer being controlled by a common phase shifter. The transfer function measured from the phase shifter to either of a pair of detectors is sinusoidal with a full cycle for each half wavelength of phase shifter travel. The phase difference between these two sinusoidal detector outputs represents the optical phase difference between a path of known distance and a path of unknown distance
ASME Code Efforts Supporting HTGRs
Energy Technology Data Exchange (ETDEWEB)
D.K. Morton
In 1999, an international collaborative initiative for the development of advanced (Generation IV) reactors was started. The idea behind this effort was to bring nuclear energy closer to the needs of sustainability, to increase proliferation resistance, and to support concepts able to produce energy (both electricity and process heat) at competitive costs. The U.S. Department of Energy has supported this effort by pursuing the development of the Next Generation Nuclear Plant, a high temperature gas-cooled reactor. This support has included research and development of pertinent data, initial regulatory discussions, and engineering support of various codes and standards development. This report discusses the various applicable American Society of Mechanical Engineers (ASME) codes and standards that are being developed to support these high temperature gascooled reactors during construction and operation. ASME is aggressively pursuing these codes and standards to support an international effort to build the next generation of advanced reactors so that all can benefit.
ASME Code Efforts Supporting HTGRs
Energy Technology Data Exchange (ETDEWEB)
D.K. Morton
In 1999, an international collaborative initiative for the development of advanced (Generation IV) reactors was started. The idea behind this effort was to bring nuclear energy closer to the needs of sustainability, to increase proliferation resistance, and to support concepts able to produce energy (both electricity and process heat) at competitive costs. The U.S. Department of Energy has supported this effort by pursuing the development of the Next Generation Nuclear Plant, a high temperature gas-cooled reactor. This support has included research and development of pertinent data, initial regulatory discussions, and engineering support of various codes and standards development. This report discusses the various applicable American Society of Mechanical Engineers (ASME) codes and standards that are being developed to support these high temperature gascooled reactors during construction and operation. ASME is aggressively pursuing these codes and standards to support an international effort to build the next generation of advanced reactors so that all can benefit.
Effort Estimation in BPMS Migration
Directory of Open Access Journals (Sweden)
Christopher Drews
Full Text Available Usually Business Process Management Systems (BPMS are highly integrated in the IT of organizations and are at the core of their business. Thus, migrating from one BPMS solution to another is not a common task. However, there are forces that are pushing organizations to perform this step, e.g. maintenance costs of legacy BPMS or the need for additional functionality. Before the actual migration, the risk and the effort must be evaluated. This work provides a framework for effort estimation regarding the technical aspects of BPMS migration. The framework provides questions for BPMS comparison and an effort evaluation schema. The applicability of the framework is evaluated based on a simplified BPMS migration scenario.
Effort problem of chemical pipelines
Energy Technology Data Exchange (ETDEWEB)
Okrajni, J.; Ciesla, M.; Mutwil, K. [Silesian Technical University, Katowice (Poland)
The problem of the technical state assessment of the chemical pipelines working under mechanical and thermal loading has been shown in the paper. The pipelines effort after the long time operating period has been analysed. Material geometrical and loading conditions of the crack initiation and crack growth process in the chosen object has been discussed. Areas of the maximal effort have been determined. The material structure charges after the long time operating period have been described. Mechanisms of the crack initiation and crack growth in the pipeline elements have been analysed and mutual relations between the chemical and mechanical influences have been shown. (orig.) 16 refs.
Summary of KOMPSAT-5 Calibration and Validation
Yang, D.; Jeong, H.; Lee, S.; Kim, B.
Korean Multi-Purpose Satellite 5 (KOMPSAT-5), equipped with high resolution X-band (9.66 GHz) Synthetic Aperture Radar (SAR), is planning to be launched on August 22, 2013. With the satellite's primary mission objective being providing Geographical Information System (GIS), Ocean monitoring and Land management, and Disaster and ENvironment monitoring (GOLDEN), it is expected that its applications for scientific research on geographical processes will be extensive. In order to meet its mission objective, the KOMPSAT-5 will provide three different kinds of SAR imaging modes; High Resolution Mode (1 m resolution, 5 km swath), Standard Mode (3 m resolution, 30 km swath), and Wide Swath Mode (20 m resolution, 100 km swath). The KOMPSAT-5 will be operated in a 550 km sun-synchronous, dawn- dusk orbit with a 28-day ground repeat cycle providing valuable image information on Earth surface day-or-night and even in bad weather condition. After successful launch of the satellite, it will go through Launch and Early Operation (LEOP) and In-Orbit Testing (IOT) period about for 6 months to carry out various tests on satellite bus and payload systems. The satellite bus system will be tested during the first 3 weeks after the launch focusing on the Attitude and Orbit Control Subsystem (AOCS) and Integrated GPS Occultation Receiver (IGOR) calibration. With the completion of bus system test, the SAR payload system will be calibrated during initial In-Flight check period (11 weeks) by the joint effort of Thales Alenia Space Italy (TAS-I) and Korea Aerospace Research Institute (KARI). The pointing and relative calibration will be carried out during this period by analyzing the doppler frequency and antenna beam pattern of reflected microwave signal from selected regions with uniform backscattering coefficients (e.g. Amazon rainforest). A dedicated SAR calibration, called primary calibration, will be allocated at the end of LEOP for 12 weeks to perform thorough calibration activities
Dosimetry and Calibration Section
International Nuclear Information System (INIS)
Otto, T.
The Dosimetry and Calibration Section fulfils two tasks within CERN's Radiation Protection Group: the Individual Dosimetry Service monitors more than 5000 persons potentially exposed to ionizing radiation on the CERN sites, and the Calibration Laboratory verifies throughout the year, at regular intervals, over 1000 instruments, monitors, and electronic dosimeters used by RP Group. The establishment of a Quality Assurance System for the Individual Dosimetry Service, a requirement of the new Swiss Ordinance for personal dosimetry, put a considerable workload on the section. Together with an external consultant it was decided to identify and then describe the different 'processes' of the routine work performed in the dosimetry service. The resulting Quality Manual was submitted to the Federal Office for Public Health in Bern in autumn. The CERN Individual Dosimetry Service will eventually be officially endorsed after a successful technical test in March 1999. On the technical side, the introduction of an automatic development machine for gamma films was very successful. It processes the dosimetric films without an operator being present, and its built-in regeneration mechanism keeps the concentration of the processing chemicals at a constant level
Piezoelectric trace vapor calibrator
International Nuclear Information System (INIS)
Verkouteren, R. Michael; Gillen, Greg; Taylor, David W.
The design and performance of a vapor generator for calibration and testing of trace chemical sensors are described. The device utilizes piezoelectric ink-jet nozzles to dispense and vaporize precisely known amounts of analyte solutions as monodisperse droplets onto a hot ceramic surface, where the generated vapors are mixed with air before exiting the device. Injected droplets are monitored by microscope with strobed illumination, and the reproducibility of droplet volumes is optimized by adjustment of piezoelectric wave form parameters. Complete vaporization of the droplets occurs only across a 10 deg. C window within the transition boiling regime of the solvent, and the minimum and maximum rates of trace analyte that may be injected and evaporated are determined by thermodynamic principles and empirical observations of droplet formation and stability. By varying solution concentrations, droplet injection rates, air flow, and the number of active nozzles, the system is designed to deliver--on demand--continuous vapor concentrations across more than six orders of magnitude (nominally 290 fg/l to 1.05 μg/l). Vapor pulses containing femtogram to microgram quantities of analyte may also be generated. Calibrated ranges of three explosive vapors at ng/l levels were generated by the device and directly measured by ion mobility spectrometry (IMS). These data demonstrate expected linear trends within the limited working range of the IMS detector and also exhibit subtle nonlinear behavior from the IMS measurement process
A Simple Accelerometer Calibrator
International Nuclear Information System (INIS)
Salam, R A; Islamy, M R F; Khairurrijal; Munir, M M; Latief, H; Irsyam, M
High possibility of earthquake could lead to the high number of victims caused by it. It also can cause other hazards such as tsunami, landslide, etc. In that case it requires a system that can examine the earthquake occurrence. Some possible system to detect earthquake is by creating a vibration sensor system using accelerometer. However, the output of the system is usually put in the form of acceleration data. Therefore, a calibrator system for accelerometer to sense the vibration is needed. In this study, a simple accelerometer calibrator has been developed using 12 V DC motor, optocoupler, Liquid Crystal Display (LCD) and AVR 328 microcontroller as controller system. The system uses the Pulse Wave Modulation (PWM) form microcontroller to control the motor rotational speed as response to vibration frequency. The frequency of vibration was read by optocoupler and then those data was used as feedback to the system. The results show that the systems could control the rotational speed and the vibration frequencies in accordance with the defined PWM. (paper)
The Complete Calibration of the Color–Redshift Relation (C3R2) Survey: Survey Overview and Data Release 1
Energy Technology Data Exchange (ETDEWEB)
Masters, Daniel C. [Infrared Processing and Analysis Center, Pasadena, CA 91125 (United States); Stern, Daniel K.; Rhodes, Jason D. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Cohen, Judith G. [California Institute of Technology, Pasadena, CA 91125 (United States); Capak, Peter L. [Spitzer Science Center, Pasadena, CA 91125 (United States); Castander, Francisco J. [Institut de Ciències de lEspai (ICE, IEEC/CSIC), E-08193 Bellaterra (Barcelona) (Spain); Paltani, Stéphane [Department of Astronomy, University of Geneva, Ch. dEcogia 16, 1290 Versoix (Switzerland)
A key goal of the Stage IV dark energy experiments Euclid , LSST, and WFIRST is to measure the growth of structure with cosmic time from weak lensing analysis over large regions of the sky. Weak lensing cosmology will be challenging: in addition to highly accurate galaxy shape measurements, statistically robust and accurate photometric redshift (photo- z ) estimates for billions of faint galaxies will be needed in order to reconstruct the three-dimensional matter distribution. Here we present an overview of and initial results from the Complete Calibration of the Color–Redshift Relation (C3R2) survey, which is designed specifically to calibrate the empirical galaxy color–redshift relation to the Euclid depth. These redshifts will also be important for the calibrations of LSST and WFIRST . The C3R2 survey is obtaining multiplexed observations with Keck (DEIMOS, LRIS, and MOSFIRE), the Gran Telescopio Canarias (GTC; OSIRIS), and the Very Large Telescope (VLT; FORS2 and KMOS) of a targeted sample of galaxies that are most important for the redshift calibration. We focus spectroscopic efforts on undersampled regions of galaxy color space identified in previous work in order to minimize the number of spectroscopic redshifts needed to map the color–redshift relation to the required accuracy. We present the C3R2 survey strategy and initial results, including the 1283 high-confidence redshifts obtained in the 2016A semester and released as Data Release 1.
The Complete Calibration of the Color–Redshift Relation (C3R2) Survey: Survey Overview and Data Release 1
International Nuclear Information System (INIS)
Masters, Daniel C.; Stern, Daniel K.; Rhodes, Jason D.; Cohen, Judith G.; Capak, Peter L.; Castander, Francisco J.; Paltani, Stéphane
A key goal of the Stage IV dark energy experiments Euclid , LSST, and WFIRST is to measure the growth of structure with cosmic time from weak lensing analysis over large regions of the sky. Weak lensing cosmology will be challenging: in addition to highly accurate galaxy shape measurements, statistically robust and accurate photometric redshift (photo- z ) estimates for billions of faint galaxies will be needed in order to reconstruct the three-dimensional matter distribution. Here we present an overview of and initial results from the Complete Calibration of the Color–Redshift Relation (C3R2) survey, which is designed specifically to calibrate the empirical galaxy color–redshift relation to the Euclid depth. These redshifts will also be important for the calibrations of LSST and WFIRST . The C3R2 survey is obtaining multiplexed observations with Keck (DEIMOS, LRIS, and MOSFIRE), the Gran Telescopio Canarias (GTC; OSIRIS), and the Very Large Telescope (VLT; FORS2 and KMOS) of a targeted sample of galaxies that are most important for the redshift calibration. We focus spectroscopic efforts on undersampled regions of galaxy color space identified in previous work in order to minimize the number of spectroscopic redshifts needed to map the color–redshift relation to the required accuracy. We present the C3R2 survey strategy and initial results, including the 1283 high-confidence redshifts obtained in the 2016A semester and released as Data Release 1.
Automated system for the calibration of magnetometers
International Nuclear Information System (INIS)
Petrucha, Vojtech; Kaspar, Petr; Ripka, Pavel; Merayo, Jose M. G.
A completely nonmagnetic calibration platform has been developed and constructed at DTU Space (Technical University of Denmark). It is intended for on-site scalar calibration of high-precise fluxgate magnetometers. An enhanced version of the same platform is being built at the Czech Technical University. There are three axes of rotation in this design (compared to two axes in the previous version). The addition of the third axis allows us to calibrate more complex devices. An electronic compass based on a vector fluxgate magnetometer and micro electro mechanical systems (MEMS) accelerometer is one example. The new platform can also be used to evaluate the parameters of the compass in all possible variations in azimuth, pitch, and roll. The system is based on piezoelectric motors, which are placed on a platform made of aluminum, brass, plastic, and glass. Position sensing is accomplished through custom-made optical incremental sensors. The system is controlled by a microcontroller, which executes commands from a computer. The properties of the system as well as calibration and measurement results will be presented
Reproductive effort in viscous populations
Pen, Ido
Here I study a kin selection model of reproductive effort, the allocation of resources to fecundity versus survival, in a patch-structured population. Breeding females remain in the same patch for life. Offspring have costly, partial long-distance dispersal and compete for breeding sites, which
CERN radiation protection (RP) calibration facilities
Energy Technology Data Exchange (ETDEWEB)
Pozzi, Fabio
Radiation protection calibration facilities are essential to ensure the correct operation of radiation protection instrumentation. Calibrations are performed in specific radiation fields according to the type of instrument to be calibrated: neutrons, photons, X-rays, beta and alpha particles. Some of the instruments are also tested in mixed radiation fields as often encountered close to high-energy particle accelerators. Moreover, calibration facilities are of great importance to evaluate the performance of prototype detectors; testing and measuring the response of a prototype detector to well-known and -characterized radiation fields contributes to improving and optimizing its design and capabilities. The CERN Radiation Protection group is in charge of performing the regular calibrations of all CERN radiation protection devices; these include operational and passive dosimeters, neutron and photon survey-meters, and fixed radiation detectors to monitor the ambient dose equivalent, H*(10), inside CERN accelerators and at the CERN borders. A new state-of-the-art radiation protection calibration facility was designed, constructed and commissioned following the related ISO recommendations to replace the previous ageing (more than 30 years old) laboratory. In fact, the new laboratory aims also at the official accreditation according to the ISO standards in order to be able to release certified calibrations. Four radiation fields are provided: neutrons, photons and beta sources and an X-ray generator. Its construction did not only involve a pure civil engineering work; many radiation protection studies were performed to provide a facility that could answer the CERN calibration needs and fulfill all related safety requirements. Monte Carlo simulations have been confirmed to be a valuable tool for the optimization of the building design, the radiation protection aspects, e.g. shielding, and, as consequence, the overall cost. After the source and irradiator installation
NVLAP activities at Department of Defense calibration laboratories
Energy Technology Data Exchange (ETDEWEB)
Schaeffer, D.M. [Defense Nuclear Agency, Alexandria, VA (United States)
There are 367 active radiological instrument calibration laboratories within the U.S. Department of Defense (DoD). Each of the four services in DoD manages, operates, and certifies the technical proficiency and competency of those laboratories under their cognizance. Each service has designated secondary calibration laboratories to trace all calibration source standards to the National Institute of Standards and Technology. Individual service radiological calibration programs and capabilities, present and future, are described, as well as the measurement quality assurance (MQA) processes for their traceability. National Voluntary Laboratory Accreditation Program (NVLAP) programs for dosimetry systems are briefly summarized. Planned NVLAP accreditation of secondary laboratories is discussed in the context of current technical challenges and future efforts.
NVLAP activities at Department of Defense calibration laboratories
International Nuclear Information System (INIS)
Schaeffer, D.M.
There are 367 active radiological instrument calibration laboratories within the U.S. Department of Defense (DoD). Each of the four services in DoD manages, operates, and certifies the technical proficiency and competency of those laboratories under their cognizance. Each service has designated secondary calibration laboratories to trace all calibration source standards to the National Institute of Standards and Technology. Individual service radiological calibration programs and capabilities, present and future, are described, as well as the measurement quality assurance (MQA) processes for their traceability. National Voluntary Laboratory Accreditation Program (NVLAP) programs for dosimetry systems are briefly summarized. Planned NVLAP accreditation of secondary laboratories is discussed in the context of current technical challenges and future efforts
Fertilizer Induced Nitrate Pollution in RCW: Calibration of the DNDC Model
El Hailouch, E.; Hornberger, G.; Crane, J. W.
Fertilizer is widely used among urban and suburban households due to the socially driven attention of homeowners to lawn appearance. With high nitrogen content, fertilizer considerably impacts the environment through the emission of the highly potent greenhouse gas nitrous oxide and the leaching of nitrate. Nitrate leaching is significantly important because fertilizer sourced nitrate that is partially leached into soil causes groundwater pollution. In an effort to model the effect of fertilizer application on the environment, the geochemical DeNitrification-DeComposition model (DNDC) was previously developed to quantitatively measure the effects of fertilizer use. The purpose of this study is to use this model more effectively on a large scale through a measurement based calibration. For this reason, leaching was measured and studied on 12 sites in the Richland Creek Watershed (RCW). Information about the fertilization and irrigation regimes of these sites was collected, along with lysimeter readings that gave nitrate fluxes in the soil. A study of the amount and variation in nitrate leaching with respect to the varying geographical locations, time of the year, and fertilization and irrigation regimes has lead to a better understanding of the driving forces behind nitrate leaching. Quantifying the influence of each of these parameters allows for a more accurate calibration of the model thus permitting use that extends beyond the RCW. Measurement of nitrate leaching on a statewide or nationwide level in turn will help guide efforts in the reduction of groundwater pollution caused by fertilizer.
Calibration of nozzle for air mass flow measurement
Uher, Jan; Kanta, Lukáš
The effort to make calibration measurement of mass flow through a nozzle was not satisfying. Traversing across the pipe radius with Pitot probe was done. The presence of overshoot behind the bend in the pipe was found. The overshoot led to an asymmetric velocity profile.
Generator Dynamic Model Validation and Parameter Calibration Using Phasor Measurements at the Point of Connection
Energy Technology Data Exchange (ETDEWEB)
Huang, Zhenyu; Du, Pengwei; Kosterev, Dmitry; Yang, Steve
Disturbance data recorded by phasor measurement units (PMU) offers opportunities to improve the integrity of dynamic models. However, manually tuning parameters through play-back events demands significant efforts and engineering experiences. In this paper, a calibration method using the extended Kalman filter (EKF) technique is proposed. The formulation of EKF with parameter calibration is discussed. Case studies are presented to demonstrate its validity. The proposed calibration method is cost-effective, complementary to traditional equipment testing for improving dynamic model quality.
On chromatic and geometrical calibration
DEFF Research Database (Denmark)
Folm-Hansen, Jørgen
The main subject of the present thesis is different methods for the geometrical and chromatic calibration of cameras in various environments. For the monochromatic issues of the calibration we present the acquisition of monochrome images, the classic monochrome aberrations and the various sources...... the correct interpolation method is described. For the chromatic issues of calibration we present the acquisition of colour and multi-spectral images, the chromatic aberrations and the various lens/camera based non-uniformities of the illumination of the image plane. It is described how the monochromatic...... to design calibration targets for both geometrical and chromatic calibration are described. We present some possible systematical errors on the detection of the objects in the calibration targets, if viewed in a non orthogonal angle, if the intensities are uneven or if the image blurring is uneven. Finally...
Development of portable flow calibrator
International Nuclear Information System (INIS)
Akiyama, Kiyomitsu; Iijima, Nobuo
In the nuclear facilities, air sniffer system is often utilized to evaluate atmospheric concentration of radioactivity in the working environment. The system collects airborne dust on the filter during some sampling period. In this method, total air flow during the sampling period is an important parameter to evaluate the radioactivity concentration correctly. Therefore, calibration for the flow meter of air sniffer system must be done periodically according to Japan Industry Standards (JIS). As we have had to available device to calibrate the flow meter in the working area, we had to remove the flow meters from the installed place and carry them to another place where calibration can be made. This work required a great deal of labor. Now we have developed a portable flow calibrator for air sniffer system which enables us to make in-site calibration of the flow meter in the working area more easily. This report describes the outline of portable flow calibrator and it's experimental results. (author)
LET calibration for CR-39 detectors in different oxygen environments
International Nuclear Information System (INIS)
Zhou, D.; Semones, E.; Weyland, M.; Benton, E.R.
High LET (linear energy transfer) radiation is the main contributor to the radiation field in low Earth orbit (LEO) in terms of dose equivalent. CR-39 plastic nuclear track detectors (PNTDs) can measure the LET spectrum and charge spectrum for the complicated radiation field in space. Previous research indicated that the sensitivity of CR-39 is different for CR-39 PNTDs working in different oxygen environments. LET calibration for CR-39 detectors in different oxygen environments is needed. Almost all the previous LET calibration work was carried out for CR-39 detectors in good-oxygen condition, LET calibration work for CR-39 in poor-oxygen condition has not been conducted until our work. Systematic LET calibrations were carried out by JSC-SRAG (Space Radiation Analysis Group) for CR-39 detectors working in different oxygen environments and abundant results of LET calibrations were obtained. This paper introduces the method for CR-39 LET calibration, presents and discusses the calibration results and some applications
Calibration of neutron detectors on the Joint European Torus.
Batistoni, Paola; Popovichev, S; Conroy, S; Lengar, I; Čufar, A; Abhangi, M; Snoj, L; Horton, L
The present paper describes the findings of the calibration of the neutron yield monitors on the Joint European Torus (JET) performed in 2013 using a 252 Cf source deployed inside the torus by the remote handling system, with particular regard to the calibration of fission chambers which provide the time resolved neutron yield from JET plasmas. The experimental data obtained in toroidal, radial, and vertical scans are presented. These data are first analysed following an analytical approach adopted in the previous neutron calibrations at JET. In this way, a calibration function for the volumetric plasma source is derived which allows us to understand the importance of the different plasma regions and of different spatial profiles of neutron emissivity on fission chamber response. Neutronics analyses have also been performed to calculate the correction factors needed to derive the plasma calibration factors taking into account the different energy spectrum and angular emission distribution of the calibrating (point) 252 Cf source, the discrete positions compared to the plasma volumetric source, and the calibration circumstances. All correction factors are presented and discussed. We discuss also the lessons learnt which are the basis for the on-going 14 MeV neutron calibration at JET and for ITER.
Quality Management and Calibration
Merkus, Henk G.
Good specification of a product's performance requires adequate characterization of relevant properties. Particulate products are usually characterized by some PSD, shape or porosity parameter(s). For proper characterization, adequate sampling, dispersion, and measurement procedures should be available or developed and skilful personnel should use appropriate, well-calibrated/qualified equipment. The characterization should be executed, in agreement with customers, in a wellorganized laboratory. All related aspects should be laid down in a quality handbook. The laboratory should provide proof for its capability to perform the characterization of stated products and/or reference materials within stated confidence limits. This can be done either by internal validation and audits or by external GLP accreditation.
SURF Model Calibration Strategy
Energy Technology Data Exchange (ETDEWEB)
Menikoff, Ralph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
SURF and SURFplus are high explosive reactive burn models for shock initiation and propagation of detonation waves. They are engineering models motivated by the ignition & growth concept of high spots and for SURFplus a second slow reaction for the energy release from carbon clustering. A key feature of the SURF model is that there is a partial decoupling between model parameters and detonation properties. This enables reduced sets of independent parameters to be calibrated sequentially for the initiation and propagation regimes. Here we focus on a methodology for tting the initiation parameters to Pop plot data based on 1-D simulations to compute a numerical Pop plot. In addition, the strategy for tting the remaining parameters for the propagation regime and failure diameter is discussed.
Calibration of Nanopositioning Stages
Directory of Open Access Journals (Sweden)
Ning Tan
Full Text Available Accuracy is one of the most important criteria for the performance evaluation of micro- and nanorobots or systems. Nanopositioning stages are used to achieve the high positioning resolution and accuracy for a wide and growing scope of applications. However, their positioning accuracy and repeatability are not well known and difficult to guarantee, which induces many drawbacks for many applications. For example, in the mechanical characterisation of biological samples, it is difficult to perform several cycles in a repeatable way so as not to induce negative influences on the study. It also prevents one from controlling accurately a tool with respect to a sample without adding additional sensors for closed loop control. This paper aims at quantifying the positioning repeatability and accuracy based on the ISO 9283:1998 standard, and analyzing factors influencing positioning accuracy onto a case study of 1-DoF (Degree-of-Freedom nanopositioning stage. The influence of thermal drift is notably quantified. Performances improvement of the nanopositioning stage are then investigated through robot calibration (i.e., open-loop approach. Two models (static and adaptive models are proposed to compensate for both geometric errors and thermal drift. Validation experiments are conducted over a long period (several days showing that the accuracy of the stage is improved from typical micrometer range to 400 nm using the static model and even down to 100 nm using the adaptive model. In addition, we extend the 1-DoF calibration to multi-DoF with a case study of a 2-DoF nanopositioning robot. Results demonstrate that the model efficiently improved the 2D accuracy from 1400 nm to 200 nm.
Radiological Calibration and Standards Facility
Federal Laboratory Consortium — PNNL maintains a state-of-the-art Radiological Calibration and Standards Laboratory on the Hanford Site at Richland, Washington. Laboratory staff provide expertise...
Portable compact multifunction IR calibrator
International Nuclear Information System (INIS)
Wyatt, C.L.; Jacobsen, L.; Steed, A.
A compact portable multifunction calibrator designed for future sensor systems is described which enables a linearity calibration for all detectors simultaneously using a near small-area source, a high-resolution mapping of the focal plane with 10 microrad setability and with a blur of less than 100 microrad, system spectral response calibration (radiometer) using a Michelson interferometer source, relative spectral response (spectrometer) using high-temperature external commercial blackbody simulators, and an absolute calibration using an internal low-temperature extended-area source. 5 references
International Nuclear Information System (INIS)
Welch, J.
Early in the commissioning it was noticed by Cecile Limborg that the calibration of the BXS spectrometer magnet seemed to be different from the strength of the BX01/BX02 magnets. First the BX01/BX02 currents were adjusted to 135 MeV and the beam energy was adjusted to make the horizontal orbit flat. Then BX01/BX02 magnets were switched off and BXS was adjusted to make the horizontal orbit in the spectrometer line flat, without changing the energy of the beam. The result was that about 140-141 MeV were required on the BXS magnet. This measurement was repeated several times by others with the same results. It was not clear what was causing the error: magnet strength or layout. A position error of about 19 mm of the BXS magnet could explain the difference. Because there was a significant misalignment of the vacuum chamber in the BXS line, the alignment of the whole spectrometer line was checked. The vacuum chamber was corrected, but the magnets were found to be in the proper alignment. So we were left with one (or conceivably two) magnet calibration errors. Because BXS is a wedged shaped magnet, the bend angle depends on the horizontal position of the incoming beam. As mentioned, an offset of the beam position of 19 mm would increase or decrease the bend angle roughly by the ratio of 135/141. The figure of 19 mm is special and caused a considerable confusion during the design and measurement of the BXS magnet. This is best illustrated in Figure 1 which was taken out of the BXS Traveler document. The distance between the horizontal midplanes of the poles and the apex of the beam path was chosen to be 19 mm so the beam is close to the good field region throughout its entire path. Thus it seemed possible that there was an error that resulted in the beam not being on this trajectory, or conversely, that the magnetic measurements were done on the wrong trajectory and the magnet was then mis-calibrated. Mechanical measurements of the vacuum chamber made in the tunnel
Hydrological processes and model representation: impact of soft data on calibration
J.G. Arnold; M.A. Youssef; H. Yen; M.J. White; A.Y. Sheshukov; A.M. Sadeghi; D.N. Moriasi; J.L. Steiner; Devendra Amatya; R.W. Skaggs; E.B. Haney; J. Jeong; M. Arabi; P.H. Gowda
Hydrologic and water quality models are increasingly used to determine the environmental impacts of climate variability and land management. Due to differing model objectives and differences in monitored data, there are currently no universally accepted procedures for model calibration and validation in the literature. In an effort to develop accepted model calibration...
Directory of Open Access Journals (Sweden)
G. Kemper
step with the help of the nadir camera and the GPS/IMU data, an initial orientation correction and radial correction were calculated. With this approach, the whole project was calculated and calibrated in one step. During the iteration process the radial and tangential parameters were switched on individually for the camera heads and after that the camera constants and principal point positions were checked and finally calibrated. Besides that, the bore side calibration can be performed either on basis of the nadir camera and their offsets, or independently for each camera without correlation to the others. This must be performed in a complete mission anyway to get stability between the single camera heads. Determining the lever arms of the nodal-points to the IMU centre needs more caution than for a single camera especially due to the strong tilt angle. Prepared all these previous steps, you get a highly accurate sensor that enables a fully automated data extraction with a rapid update of you existing data. Frequently monitoring urban dynamics is then possible in fully 3D environment.
Exposure-rate calibration using large-area calibration pads
International Nuclear Information System (INIS)
Novak, E.F.
The US Department of Energy (DOE) Office of Remedial Action and Waste Technology established the Technical Measurements Center (TMC) at the DOE Grand Junction Projects Office (GJPO) in Grand Junction, Colorado, to standardize, calibrate, and compare measurements made in support of DOE remedial action programs. A set of large-area, radioelement-enriched concrete pads was constructed by the DOE in 1978 at the Walker Field Airport in Grand Junction for use as calibration standards for airborne gamma-ray spectrometer systems. The use of these pads was investigated by the TMC as potential calibration standards for portable scintillometers employed in measuring gamma-ray exposure rates at Uranium Mill Tailings Remedial Action (UMTRA) project sites. Data acquired on the pads using a pressurized ionization chamber (PIC) and three scintillometers are presented as an illustration of an instrumental calibration. Conclusions and recommended calibration procedures are discussed, based on the results of these data
Calibration of radon-222 detectors using closed circuit radium-226 sources
International Nuclear Information System (INIS)
Perna, Allan Felipe Nunes; Paschuk, Sergei Anatolyevich; Correa, Janine Nicolosi; Del Claro, Flavia
This paper presents the results of the calibration of the Radon-222 detectors used by the Laboratories specializing in measuring natural radiation from this gas. The research was conducted in collaboration between UTFPR, CDTN/CNEN, UFRN and IRD/CNEN. During the calibration the detectors were exposed in isolated chambers with radioactive calibrated sources. The calibration procedure was supported with four instant radon monitors AlphaGUARD (SAPHYMO Co.) responsible for radon activity measurements in the experimental chamber. The calibration procedure resulted an equation that relates the number of tracks found in solid-state detector CR-39 (Track-Etch detector) with the concentration of radon in the atmosphere. Obtained results are compatible with previously performed calibration at the National Institute of Radiological Sciences (NIRS, Japan) using high activity levels of radon in air. Present results of calibration give the possibility to expand the calibration curve of CR-39 for medium and low activity levels of radon. (author)
Enhancing Seismic Calibration Research Through Software Automation and Scientific Information Management
Energy Technology Data Exchange (ETDEWEB)
Ruppert, S D; Dodge, D A; Ganzberger, M D; Harris, D B; Hauk, T F
The National Nuclear Security Administration (NNSA) Ground-Based Nuclear Explosion Monitoring Research and Development (GNEMRD) Program at LLNL continues to make significant progress enhancing the process of deriving seismic calibrations and performing scientific integration, analysis, and information management with software automation tools. Our tool efforts address the problematic issues of very large datasets and varied formats encountered during seismic calibration research. New information management and analysis tools have resulted in demonstrated gains in efficiency of producing scientific data products and improved accuracy of derived seismic calibrations. In contrast to previous years, software development work this past year has emphasized development of automation at the data ingestion level. This change reflects a gradually-changing emphasis in our program from processing a few large data sets that result in a single integrated delivery, to processing many different data sets from a variety of sources. The increase in the number of sources had resulted in a large increase in the amount of metadata relative to the final volume of research products. Software developed this year addresses the problems of: (1) Efficient metadata ingestion and conflict resolution; (2) Automated ingestion of bulletin information; (3) Automated ingestion of waveform information from global data centers; and (4) Site Metadata and Response transformation required for certain products. This year, we also made a significant step forward in meeting a long-standing goal of developing and using a waveform correlation framework. Our objective for such a framework is to extract additional calibration data (e.g. mining blasts) and to study the extent to which correlated seismicity can be found in global and regional scale environments.
Self-calibrating pseudolite arrays: Theory and experiment
Lemaster, Edward Alan
Tasks envisioned for future-generation Mars rovers---sample collection, area survey, resource mining, habitat construction, etc.---will require greatly enhanced navigational capabilities over those possessed by the 1997 Mars Sojourner rover. Many of these tasks will involve cooperative efforts by multiple rovers and other agents, necessitating both high accuracy and the ability to share navigation information among different users. On Earth, satellite-based carrier-phase differential GPS provides a means of delivering centimeter-level, drift-free positioning to multiple users in contact with a reference base station. It would be highly desirable to have a similar navigational capability for use in Mars exploration. This research has originated a new local-area navigation system---a Self-Calibrating Pseudolite Array (SCPA)---that can provide centimeter-level localization to multiple rovers by utilizing GPS-based pseudolite transceivers deployed in a ground-based array. Such a system of localized beacons can replace or augment a system based on orbiting satellite transmitters. Previous pseudolite arrays have relied upon a priori information to survey the locations of the pseudolites, which must be accurately known to enable navigation within the array. In contrast, an SCPA does not rely upon other measurement sources to determine these pseudolite locations. This independence is a key requirement for autonomous deployment on Mars, and is accomplished through the use of GPS transceivers containing both transmit and receive components and through algorithms that utilize limited motion of a transceiver-bearing rover to determine the locations of the stationary transceivers. This dissertation describes the theory and operation of GPS transceivers, and how they can be used for navigation within a Self-Calibrating Pseudolite Array. It presents new algorithms that can be used to self-survey such arrays robustly using no a priori information, even under adverse conditions
LANL MTI calibration team experience
Bender, Steven C.; Atkins, William H.; Clodius, William B.; Little, Cynthia K.; Christensen, R. Wynn
The Multispectral Thermal Imager (MTI) was designed as an imaging radiometer with absolute calibration requirements established by Department of Energy (DOE) mission goals. Particular emphasis was given to water surface temperature retrieval using two mid wave and three long wave infrared spectral bands, the fundamental requirement was a surface temperature determination of 1K at the 68% confidence level. For the ten solar reflective bands a one-sigma radiometric performance goal of 3% was established. In order to address these technical challenges a calibration facility was constructed containing newly designed sources that were calibrated at NIST. Additionally, the design of the payload and its onboard calibration system supported post launch maintenance and update of the ground calibration. The on-orbit calibration philosophy also included vicarious techniques using ocean buoys, playas and other instrumented sites; these became increasingly important subsequent to an electrical failure which disabled the onboard calibration system. This paper offers various relevant lessons learned in the eight-year process of reducing to practice the calibration capability required by the scientific mission. The discussion presented will include observations pertinent to operational and procedural issues as well as hardware experiences; the validity of some of the initial assumptions will also be explored.
Field calibration of cup anemometers
DEFF Research Database (Denmark)
Kristensen, L.; Jensen, G.; Hansen, A.
An outdoor calibration facility for cup anemometers, where the signals from 10 anemometers of which at least one is a reference can be can be recorded simultaneously, has been established. The results are discussed with special emphasis on the statisticalsignificance of the calibration expressions...
International Nuclear Information System (INIS)
Rizvi, H.M.
The data obtained from these tests determine the dose rate of the two cobalt sources in SRTC. Building 774-A houses one of these sources while the other resides in room C-067 of Building 773-A. The data from this experiment shows the following: (1) The dose rate of the No.2 cobalt source in Building 774-A measured 1.073 x 10 5 rad/h (June 17, 1999). The dose rate of the Shepherd Model 109 Gamma cobalt source in Building 773-A measured 9.27 x 10 5 rad/h (June 25, 1999). These rates come from placing the graduated cylinder containing the dosimeter solution in the center of the irradiation chamber. (2) Two calibration tests in the 774-A source placed the graduated cylinder with the dosimeter solution approximately 1.5 inches off center in the axial direction. This movement of the sample reduced the measured dose rate 0.92% from 1.083 x 10 5 rad/h to 1.073 x 10 5 rad/h. and (3) A similar test in the cobalt source in 773-A placed the graduated cylinder approximately 2.0 inches off center in the axial direction. This change in position reduced the measured dose rate by 10.34% from 1.036 x 10 6 to 9.27 x 10 5 . This testing used chemical dosimetry to measure the dose rate of a radioactive source. In this method, one determines the dose by the chemical change that takes place in the dosimeter. For this calibration experiment, the author used a Fricke (ferrous ammonium sulfate) dosimeter. This solution works well for dose rates to 10 7 rad/h. During irradiation of the Fricke dosimeter solution the Fe 2+ ions ionize to Fe 3+ . When this occurs, the solution acquires a slightly darker tint (not visible to the human eye). To determine the magnitude of the change in Fe ions, one places the solution in an UV-VIS Spectrophotometer. The UV-VIS Spectrophotometer measures the absorbency of the solution. Dividing the absorbency by the total time (in minutes) of exposure yields the dose rate
Voluntary versus Enforced Team Effort
Directory of Open Access Journals (Sweden)
Claudia Keser
Full Text Available We present a model where each of two players chooses between remuneration based on either private or team effort. Although at least one of the players has the equilibrium strategy to choose private remuneration, we frequently observe both players to choose team remuneration in a series of laboratory experiments. This allows for high cooperation payoffs but also provides individual free-riding incentives. Due to significant cooperation, we observe that, in team remuneration, participants make higher profits than in private remuneration. We also observe that, when participants are not given the option of private remuneration, they cooperate significantly less.
Preoperative screening: value of previous tests.
Macpherson, D S; Snow, R; Lofgren, R P
To determine the frequency of tests done in the year before elective surgery that might substitute for preoperative screening tests and to determine the frequency of test results that change from a normal value to a value likely to alter perioperative management. Retrospective cohort analysis of computerized laboratory data (complete blood count, sodium, potassium, and creatinine levels, prothrombin time, and partial thromboplastin time). Urban tertiary care Veterans Affairs Hospital. Consecutive sample of 1109 patients who had elective surgery in 1988. At admission, 7549 preoperative tests were done, 47% of which duplicated tests performed in the previous year. Of 3096 previous results that were normal as defined by hospital reference range and done closest to the time of but before admission (median interval, 2 months), 13 (0.4%; 95% CI, 0.2% to 0.7%), repeat values were outside a range considered acceptable for surgery. Most of the abnormalities were predictable from the patient's history, and most were not noted in the medical record. Of 461 previous tests that were abnormal, 78 (17%; CI, 13% to 20%) repeat values at admission were outside a range considered acceptable for surgery (P less than 0.001, frequency of clinically important abnormalities of patients with normal previous results with those with abnormal previous results). Physicians evaluating patients preoperatively could safely substitute the previous test results analyzed in this study for preoperative screening tests if the previous tests are normal and no obvious indication for retesting is present.
Liquid Krypton Calorimeter Calibration Software
Hughes, Christina Lindsay
Calibration of the liquid krypton calorimeter (LKr) of the NA62 experiment is managed by a set of standalone programs, or an online calibration driver. These programs are similar to those used by NA48, but have been updated to utilize classes and translated to C++ while maintaining a common functionality. A set of classes developed to handle communication with hardware was used to develop the three standalone programs as well as the main driver program for online calibration between bursts. The main calibration driver has been designed to respond to run control commands and receive burst data, both transmitted via DIM. In order to facilitate the process of reading in calibration parameters, a serializable class has been introduced, allowing the replacement of standard text files with XML configuration files.
Permanently calibrated interpolating time counter
International Nuclear Information System (INIS)
Jachna, Z; Szplet, R; Kwiatkowski, P; Różyc, K
We propose a new architecture of an integrated time interval counter that provides its permanent calibration in the background. Time interval measurement and the calibration procedure are based on the use of a two-stage interpolation method and parallel processing of measurement and calibration data. The parallel processing is achieved by a doubling of two-stage interpolators in measurement channels of the counter, and by an appropriate extension of control logic. Such modification allows the updating of transfer characteristics of interpolators without the need to break a theoretically infinite measurement session. We describe the principle of permanent calibration, its implementation and influence on the quality of the counter. The precision of the presented counter is kept at a constant level (below 20 ps) despite significant changes in the ambient temperature (from −10 to 60 °C), which can cause a sevenfold decrease in the precision of the counter with a traditional calibration procedure. (paper)
Smith, V.L.; Carstensen, H.K.
An improved time calibrated sweep circuit is presented, which extends the range of usefulness of conventional oscilloscopes as utilized for time calibrated display applications in accordance with U. S. Patent No. 2,832,002. Principal novelty resides in the provision of a pair of separate signal paths, each of which is phase and amplitude adjustable, to connect a high-frequency calibration oscillator to the output of a sawtooth generator also connected to the respective horizontal deflection plates of an oscilloscope cathode ray tube. The amplitude and phase of the calibration oscillator signals in the two signal paths are adjusted to balance out feedthrough currents capacitively coupled at high frequencies of the calibration oscillator from each horizontal deflection plate to the vertical plates of the cathode ray tube.
Analysis Efforts Supporting NSTX Upgrades
International Nuclear Information System (INIS)
Zhang, H.; Titus, P.; Rogoff, P.; Zolfaghari, A.; Mangra, D.; Smith, M.
The National Spherical Torus Experiment (NSTX) is a low aspect ratio, spherical torus (ST) configuration device which is located at Princeton Plasma Physics Laboratory (PPPL) This device is presently being updated to enhance its physics by doubling the TF field to 1 Tesla and increasing the plasma current to 2 Mega-amperes. The upgrades include a replacement of the centerstack and addition of a second neutral beam. The upgrade analyses have two missions. The first is to support design of new components, principally the centerstack, the second is to qualify existing NSTX components for higher loads, which will increase by a factor of four. Cost efficiency was a design goal for new equipment qualification, and reanalysis of the existing components. Showing that older components can sustain the increased loads has been a challenging effort in which designs had to be developed that would limit loading on weaker components, and would minimize the extent of modifications needed. Two areas representing this effort have been chosen to describe in more details: analysis of the current distribution in the new TF inner legs, and, second, analysis of the out-of-plane support of the existing TF outer legs.
APS Education and Diversity Efforts
Prestridge, Katherine; Hodapp, Theodore
American Physical Society (APS) has a wide range of education and diversity programs and activities, including programs that improve physics education, increase diversity, provide outreach to the public, and impact public policy. We present the latest programs spearheaded by the Committee on the Status of Women in Physics (CSWP), with highlights from other diversity and education efforts. The CSWP is working to increase the fraction of women in physics, understand and implement solutions for gender-specific issues, enhance professional development opportunities for women in physics, and remedy issues that impact gender inequality in physics. The Conferences for Undergraduate Women in Physics, Professional Skills Development Workshops, and our new Professional Skills program for students and postdocs are all working towards meeting these goals. The CSWP also has site visit and conversation visit programs, where department chairs request that the APS assess the climate for women in their departments or facilitate climate discussions. APS also has two significant programs to increase participation by underrepresented minorities (URM). The newest program, the APS National Mentoring Community, is working to provide mentoring to URM undergraduates, and the APS Bridge Program is an established effort that is dramatically increasing the number of URM PhDs in physics.
In-Flight Calibration Processes for the MMS Fluxgate Magnetometers
Bromund, K. R.; Leinweber, H. K.; Plaschke, F.; Strangeway, R. J.; Magnes, W.; Fischer, D.; Nakamura, R.; Anderson, B. J.; Russell, C. T.; Baumjohann, W.; Chutter, M.; Torbert, R. B.; Le, G.; Slavin, J. A.; Kepko, L.
The calibration effort for the Magnetospheric Multiscale Mission (MMS) Analog Fluxgate (AFG) and Digital Fluxgate (DFG) magnetometers is a coordinated effort between three primary institutions: University of California, Los Angeles (UCLA); Space Research Institute, Graz, Austria (IWF); and Goddard Space Flight Center (GSFC). Since the successful deployment of all 8 magnetometers on 17 March 2015, the effort to confirm and update the ground calibrations has been underway during the MMS commissioning phase. The in-flight calibration processes evaluate twelve parameters that determine the alignment, orthogonalization, offsets, and gains for all 8 magnetometers using algorithms originally developed by UCLA and the Technical University of Braunschweig and tailored to MMS by IWF, UCLA, and GSFC. We focus on the processes run at GSFC to determine the eight parameters associated with spin tones and harmonics. We will also discuss the processing flow and interchange of parameters between GSFC, IWF, and UCLA. IWF determines the low range spin axis offsets using the Electron Drift Instrument (EDI). UCLA determines the absolute gains and sensor azimuth orientation using Earth field comparisons. We evaluate the performance achieved for MMS and give examples of the quality of the resulting calibrations.
Automatic electromagnetic valve for previous vacuum
International Nuclear Information System (INIS)
Granados, C. E.; Martin, F.
A valve which permits the maintenance of an installation vacuum when electric current fails is described. It also lets the air in the previous vacuum bomb to prevent the oil ascending in the vacuum tubes. (Author)
Simple laser vision sensor calibration for surface profiling applications
Abu-Nabah, Bassam A.; ElSoussi, Adnane O.; Al Alami, Abed ElRahman K.
Due to the relatively large structures in the Oil and Gas industry, original equipment manufacturers (OEMs) have been implementing custom-designed laser vision sensor (LVS) surface profiling systems as part of quality control in their manufacturing processes. The rough manufacturing environment and the continuous movement and misalignment of these custom-designed tools adversely affect the accuracy of laser-based vision surface profiling applications. Accordingly, Oil and Gas businesses have been raising the demand from the OEMs to implement practical and robust LVS calibration techniques prior to running any visual inspections. This effort introduces an LVS calibration technique representing a simplified version of two known calibration techniques, which are commonly implemented to obtain a calibrated LVS system for surface profiling applications. Both calibration techniques are implemented virtually and experimentally to scan simulated and three-dimensional (3D) printed features of known profiles, respectively. Scanned data is transformed from the camera frame to points in the world coordinate system and compared with the input profiles to validate the introduced calibration technique capability against the more complex approach and preliminarily assess the measurement technique for weld profiling applications. Moreover, the sensitivity to stand-off distances is analyzed to illustrate the practicality of the presented technique.
Validation of smart sensor technologies for instrument calibration reduction in nuclear power plants
International Nuclear Information System (INIS)
Hashemian, H.M.; Mitchell, D.W.; Petersen, K.M.; Shell, C.S.
This report presents the preliminary results of a research and development project on the validation of new techniques for on-line testing of calibration drift of process instrumentation channels in nuclear power plants. These techniques generally involve a computer-based data acquisition and data analysis system to trend the output of a large number of instrument channels and identify the channels that have drifted out of tolerance. This helps limit the calibration effort to those channels which need the calibration, as opposed to the current nuclear industry practice of calibrating essentially all the safety-related instrument channels at every refueling outage
Termination of prehospital resuscitative efforts
DEFF Research Database (Denmark)
Mikkelsen, Søren; Schaffalitzky de Muckadell, Caroline; Binderup, Lars Grassmé
-and-death decision-making in the patient's medical records is required. We suggest that a template be implemented in the prehospital medical records describing the basis for any ethical decisions. This template should contain information regarding the persons involved in the deliberations and notes on ethical......BACKGROUND: Discussions on ethical aspects of life-and-death decisions within the hospital are often made in plenary. The prehospital physician, however, may be faced with ethical dilemmas in life-and-death decisions when time-critical decisions to initiate or refrain from resuscitative efforts...... need to be taken without the possibility to discuss matters with colleagues. Little is known whether these considerations regarding ethical issues in crucial life-and-death decisions are documented prehospitally. This is a review of the ethical considerations documented in the prehospital medical...
Automatic Camera Calibration Using Multiple Sets of Pairwise Correspondences.
Vasconcelos, Francisco; Barreto, Joao P; Boyer, Edmond
We propose a new method to add an uncalibrated node into a network of calibrated cameras using only pairwise point correspondences. While previous methods perform this task using triple correspondences, these are often difficult to establish when there is limited overlap between different views. In such challenging cases we must rely on pairwise correspondences and our solution becomes more advantageous. Our method includes an 11-point minimal solution for the intrinsic and extrinsic calibration of a camera from pairwise correspondences with other two calibrated cameras, and a new inlier selection framework that extends the traditional RANSAC family of algorithms to sampling across multiple datasets. Our method is validated on different application scenarios where a lack of triple correspondences might occur: addition of a new node to a camera network; calibration and motion estimation of a moving camera inside a camera network; and addition of views with limited overlap to a Structure-from-Motion model.
International Nuclear Information System (INIS)
Burns, J.E.
Since the recent publication of IAEA Technical Reports Series No. 374 ''Calibration of Dosimeters Used in Radiotheraphy'', there have been a number of queries about the origin of, and the rationale behind, the X-ray qualities recommended for calibration purposes. The simple answer is that these are the qualities derived at the UK National Physical Laboratory (NPL) in 1971 for calibration of therapy-level dosimeters and which are still in use for that purpose. As some SSDLs may have difficulties in adopting these exact combinations of kV and filtration. This paper discusses the basic ideas involved, and how to go about deriving a different series of qualities
Spectrophotometric calibration system for DECam
Rheault, J.-P.; DePoy, D. L.; Marshall, J. L.; Prochaska, T.; Allen, R.; Wise, J.; Martin, E.; Williams, P.
We describe a spectrophotometric calibration system that is being implemented as part of the DES DECam project at the Blanco 4 meter at CTIO. Our calibration system uses a 1nm wide tunable source to measure the instrumental response function of the telescope optics and detector from 300nm up to 1100nm. This calibration will be performed regularly to monitor any change in the transmission function of the telescope during the 5 year survey. The system consists of a monochromator based tunable light source that provides illumination on a dome flat that is monitored by calibrated photodiodes that allow us to measure the telescope throughput as a function of wavelength. Our system has a peak output power of 2 mW, equivalent to a flux of approximately 800 photons/s/pixel on DECam.
Recommended inorganic chemicals for calibration
International Nuclear Information System (INIS)
Moody, J.R.; Greenberg, R.R.; Pratt, K.W.; Rains, T.C.
All analytical techniques depend on the use of calibration chemicals to relate analyte concentration to an instrumental parameter. A fundamental component in the preparation of calibration solutions is the weighing of a pure chemical or metal before preparing a solution standard. The analyst must be assured that the purity, stoichiometry, and assay of the chemical are known. These terms have different meanings, and each has an important influence. This report is intended to assist the analyst in the selection and use of chemical standards for instrumental calibration. Purity, stoichiometry, and preparation of solutions for different purposes are discussed, and a critical evaluation of the best materials available for each element is presented for use in preparing solutions or calibration standards. Information on the chemical form, source, purity, drying, and appropriate precautions is given. In some cases, multiple sources or chemical forms are available. Certain radioactive elements, the transuranic elements, and the noble gases are not considered
Field calibration of cup anemometers
Energy Technology Data Exchange (ETDEWEB)
Kristensen, L.; Jensen, G.; Hansen, A.; Kirkegaard, P.
An outdoor calibration facility for cup anemometers, where the signals from 10 anemometers of which at least one is a reference can be recorded simultaneously, has been established. The results are discussed with special emphasis on the statistical significance of the calibration expressions. It is concluded that the method has the advantage that many anemometers can be calibrated accurately with a minimum of work and cost. The obvious disadvantage is that the calibration of a set of anemometers may take more than one month in order to have wind speeds covering a sufficiently large magnitude range in a wind direction sector where we can be sure that the instruments are exposed to identical, simultaneous wind flows. Another main conclusion is that statistical uncertainty must be carefully evaluated since the individual 10 minute wind-speed averages are not statistically independent. (au)
Calibration of radiation monitoring instruments
International Nuclear Information System (INIS)
Radiation protection is dependent on good radiation monitoring, and properly calibrated instruments are essential for this work. Simple procedures for periodically checking and recalibrating different kinds of radiation monitoring instruments are shown in this training film
Calibration of "Babyline" RP instruments
If you have old RP instrumentation of the "Babyline" type, as shown in the photo, please contact the Radiation Protection Group (Joffrey Germa, 73171) to have the instrument checked and calibrated. Thank you. Radiation Protection Group
Calibration of radiation monitoring instruments
Energy Technology Data Exchange (ETDEWEB)
Radiation protection is dependent on good radiation monitoring, and properly calibrated instruments are essential for this work. Simple procedures for periodically checking and recalibrating different kinds of radiation monitoring instruments are shown in this training film
77 FR 70176 - Previous Participation Certification
... participants' previous participation in government programs and ensure that the past record is acceptable prior... information is designed to be 100 percent automated and digital submission of all data and certifications is... government programs and ensure that the past record is acceptable prior to granting approval to participate...
On the Tengiz petroleum deposit previous study
International Nuclear Information System (INIS)
Nysangaliev, A.N.; Kuspangaliev, T.K.
Tengiz petroleum deposit previous study is described. Some consideration about structure of productive formation, specific characteristic properties of petroleum-bearing collectors are presented. Recommendation on their detail study and using of experience on exploration and development of petroleum deposit which have analogy on most important geological and industrial parameters are given. (author)
Subsequent pregnancy outcome after previous foetal death
Nijkamp, J. W.; Korteweg, F. J.; Holm, J. P.; Timmer, A.; Erwich, J. J. H. M.; van Pampus, M. G.
Objective: A history of foetal death is a risk factor for complications and foetal death in subsequent pregnancies as most previous risk factors remain present and an underlying cause of death may recur. The purpose of this study was to evaluate subsequent pregnancy outcome after foetal death and to
[Limitation of the therapeutic effort].
Herreros, B; Palacios, G; Pacho, E
The limitation of the therapeutic effort (LTE) consists in not applying extraordinary or disproportionate measures for therapeutic purposes that are proposed for a patient with poor life prognosis and/or poor quality of life. There are two types. The first is to not initiate certain measures or to withdraw them when they are established. A decision of the LTE should be based on some rigorous criteria, so that we make the following proposal. First, it is necessary to know the most relevant details of the case to make a decision: the preferences of the patient, the preferences of the family when pertinent, the prognosis (severity), the quality of life and distribution of the limited resources. After, the decision should be made. In this phase, participatory deliberation should be established to clarify the end of the intervention. Finally, if it is decided to perform an LTE, it should be decided how to do it. Special procedures, disproportionate measures, that are useless and vain should not be initiated for the therapeutic objective designed (withdraw them if they have been established). When it has been decided to treat a condition (interim measures), the treatment should be maintained. This complex phase may need stratification of he measures. Finally, the necessary palliative measures should be established. Copyright © 2011 Elsevier España, S.L. All rights reserved.
Rotary mode system initial instrument calibration
International Nuclear Information System (INIS)
Johns, B.R.
The attached report contains the vendor calibration procedures used for the initial instrument calibration of the rotary core sampling equipment. The procedures are from approved vendor information files
Pressures Detector Calibration and Measurement
This is report of my first and second projects (of 3) in NA61. I did data taking and analysis in order to do calibration of pressure detectors and verified it. I analyzed the data by ROOT software using the C ++ programming language. The first part of my project was determination of calibration factor of pressure sensors. Based on that result, I examined the relation between pressure drop, gas flow rate of in paper filter and its diameter.
Development of an in situ calibration technique for combustible gas detectors
Shumar, J. W.; Wynveen, R. A.; Lance, N., Jr.; Lantz, J. B.
This paper describes the development of an in situ calibration procedure for combustible gas detectors (CGD). The CGD will be a necessary device for future space vehicles as many subsystems in the Environmental Control/Life Support System utilize or produce hydrogen (H2) gas. Existing calibration techniques are time-consuming and require support equipment such as an environmental chamber and calibration gas supply. The in situ calibration procedure involves utilization of a water vapor electrolysis cell for the automatic in situ generation of a H2/air calibration mixture within the flame arrestor of the CGD. The development effort concluded with the successful demonstration of in situ span calibrations of a CGD.
The KLOE online calibration system
International Nuclear Information System (INIS)
Pasqualucci, E.; Alexander, G.; Aloisio, A.
Based on all the features of the KLOE online software, the online calibration system performs current calibration quality checking in real time and starts automatically new calibration procedures when needed. A calibration manager process controls the system, implementing the interface to the online system, receiving information from the run control and translating its state transitions to a separate state machine. It acts as a 'calibration run controller' and performs failure recovery when requested by a set of process checkers. The core of the system is a multi-threaded OO histogram server that receives histogramming commands by remote processes and operates on local ROOT histograms. A client library and C, fortran and C++ application interface libraries allow the user to connect and define his own histogram or read histograms owned by others using an book-like interface. Several calibration processes running in parallel in a distributed, multiplatform environment can fill the same histograms, allowing fast external information check. A monitor thread allow remote browsing for visual inspection. Pre-filtered data are read in non-privileged spy mode from the data acquisition system via the Kloe Integrated Dataflow. The main characteristics of the system are presented
Health Physics Society program for accreditation of calibration laboratories
International Nuclear Information System (INIS)
West, L.; Masse, F.X.; Swinth, K.L.
The Health Physics Society has instituted a new program for accreditation of organizations that calibrate radiation survey instruments. The purpose of the program is to provide radiation protection professionals with an expanded means of direct and indirect access to national standards, thus introducing a means for improving the uniformity, accuracy, and quality of ionizing radiation field measurements. Secondary accredited laboratories are expected to provide a regional support basis. Tertiary accredited laboratories are expected to operate on a more local basis and provide readily available expertise to end users. The accreditation process is an effort to provide better measurement assurance for surveys of radiation fields. The status of the accreditation program, general criteria, gamma-ray calibration criteria, and x-ray calibration criteria are reviewed
A machine vision system for the calibration of digital thermometers
International Nuclear Information System (INIS)
Vázquez-Fernández, Esteban; Dacal-Nieto, Angel; González-Jorge, Higinio; Alvarez-Valado, Victor; Martín, Fernando; Formella, Arno
Automation is a key point in many industrial tasks such as calibration and metrology. In this context, machine vision has shown to be a useful tool for automation support, especially when there is no other option available. A system for the calibration of portable measurement devices has been developed. The system uses machine vision to obtain the numerical values shown by displays. A new approach based on human perception of digits, which works in parallel with other more classical classifiers, has been created. The results show the benefits of the system in terms of its usability and robustness, obtaining a success rate higher than 99% in display recognition. The system saves time and effort, and offers the possibility of scheduling calibration tasks without excessive attention by the laboratory technicians
Mental and physical effort affect vigilance differently
Smit, A.S.; Eling, P.A.T.M.; Hopman, M.T.E.; Coenen, A.M.L.
Both physical and mental effort are thought to affect vigilance. Mental effort is known for its vigilance declining effects, but the effects of physical effort are less clear. This study investigated whether these two forms of effort affect the EEG and subjective alertness differently. Participants
Mental and physical effort affect vigilance differently.
Smit, A.S.; Eling, P.A.T.M.; Hopman, M.T.E.; Coenen, A.M.L.
Both physical and mental effort are thought to affect vigilance. Mental effort is known for its vigilance declining effects, but the effects of physical effort are less clear. This study investigated whether these two forms of effort affect the EEG and subjective alertness differently. Participants
Development of Method for X-band Weather Radar Calibration
DEFF Research Database (Denmark)
Nielsen, Jesper Ellerbæk; Thorndahl, Søren Liedtke; Rasmussen, Michael R.
Calibration of the X-band LAWR (Local Area Weather Radar) is traditionally based on an assumed linear relation between the LAWRradar output and the rainfall intensity. However, closer inspections of the data reveal that the validity of this linear assumption is doubtful. Previous studies of this ......Calibration of the X-band LAWR (Local Area Weather Radar) is traditionally based on an assumed linear relation between the LAWRradar output and the rainfall intensity. However, closer inspections of the data reveal that the validity of this linear assumption is doubtful. Previous studies...... of this type of weather radar have also illustrated that the radar commonly has difficulties in estimating high rain rates. Therefore, a new radar–rainfall transformation model and a calibration method have been developed. The new method is based on nonlinear assumptions and is aimed at describing the whole...
Subsequent childbirth after a previous traumatic birth.
Beck, Cheryl Tatano; Watson, Sue
Nine percent of new mothers in the United States who participated in the Listening to Mothers II Postpartum Survey screened positive for meeting the Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria for posttraumatic stress disorder after childbirth. Women who have had a traumatic birth experience report fewer subsequent children and a longer length of time before their second baby. Childbirth-related posttraumatic stress disorder impacts couples' physical relationship, communication, conflict, emotions, and bonding with their children. The purpose of this study was to describe the meaning of women's experiences of a subsequent childbirth after a previous traumatic birth. Phenomenology was the research design used. An international sample of 35 women participated in this Internet study. Women were asked, "Please describe in as much detail as you can remember your subsequent pregnancy, labor, and delivery following your previous traumatic birth." Colaizzi's phenomenological data analysis approach was used to analyze the stories of the 35 women. Data analysis yielded four themes: (a) riding the turbulent wave of panic during pregnancy; (b) strategizing: attempts to reclaim their body and complete the journey to motherhood; (c) bringing reverence to the birthing process and empowering women; and (d) still elusive: the longed-for healing birth experience. Subsequent childbirth after a previous birth trauma has the potential to either heal or retraumatize women. During pregnancy, women need permission and encouragement to grieve their prior traumatic births to help remove the burden of their invisible pain.
On the long-term stability of calibration standards in different matrices.
Kandić, A; Vukanac, I; Djurašević, M; Novković, D; Šešlak, B; Milošević, Z
In order to assure Quality Control in accordance with ISO/IEC 17025, it was important, from metrological point of view, to examine the long-term stability of calibration standards previously prepared. Comprehensive reconsideration on efficiency curves with respect to the ageing of calibration standards is presented in this paper. The calibration standards were re-used after a period of 5 years and analysis of the results showed discrepancies in efficiency values. Copyright © 2012 Elsevier Ltd. All rights reserved.
Investigation on calibration parameter of mammography calibration facilities at MINT
International Nuclear Information System (INIS)
Asmaliza Hashim; Wan Hazlinda Ismail; Md Saion Salikin; Muhammad Jamal Md Isa; Azuhar Ripin; Norriza Mohd Isa
A mammography calibration facility has been established in the Medical Physics Laboratory, Malaysian Institute for Nuclear Technology Research (MINT). The calibration facility is established at the national level mainly to provide calibration services for radiation measuring test instruments or test tools used in quality assurance programme in mammography, which is being implemented in Malaysia. One of the accepted parameters that determine the quality of a radiation beam is the homogeneity coefficient. It is determined from the values of the 1 st and 2 nd Half Value Layer (HVL). In this paper, the consistency of the mammography machine beam qualities that is available in MINT, is investigated and presented. For calibration purposes, five radiation qualities namely 23, 25, 28, 30 and 35 kV, selectable from the control panel of the X-ray machine is used. Important parameters that are set for this calibration facility are exposure time, tube current, focal spot to detector distance (FDD) and beam size at specific distance. The values of homogeneity coefficient of this laboratory for the past few years tip to now be presented in this paper. Backscatter radiations are also considered in this investigation. (Author)
CALIPSO lidar calibration at 532 nm: version 4 nighttime algorithm
Kar, Jayanta; Vaughan, Mark A.; Lee, Kam-Pui; Tackett, Jason L.; Avery, Melody A.; Garnier, Anne; Getzewich, Brian J.; Hunt, William H.; Josset, Damien; Liu, Zhaoyan; Lucker, Patricia L.; Magill, Brian; Omar, Ali H.; Pelon, Jacques; Rogers, Raymond R.; Toth, Travis D.; Trepte, Charles R.; Vernier, Jean-Paul; Winker, David M.; Young, Stuart A.
Data products from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP) on board Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) were recently updated following the implementation of new (version 4) calibration algorithms for all of the Level 1 attenuated backscatter measurements. In this work we present the motivation for and the implementation of the version 4 nighttime 532 nm parallel channel calibration. The nighttime 532 nm calibration is the most fundamental calibration of CALIOP data, since all of CALIOP's other radiometric calibration procedures - i.e., the 532 nm daytime calibration and the 1064 nm calibrations during both nighttime and daytime - depend either directly or indirectly on the 532 nm nighttime calibration. The accuracy of the 532 nm nighttime calibration has been significantly improved by raising the molecular normalization altitude from 30-34 km to the upper possible signal acquisition range of 36-39 km to substantially reduce stratospheric aerosol contamination. Due to the greatly reduced molecular number density and consequently reduced signal-to-noise ratio (SNR) at these higher altitudes, the signal is now averaged over a larger number of samples using data from multiple adjacent granules. Additionally, an enhanced strategy for filtering the radiation-induced noise from high-energy particles was adopted. Further, the meteorological model used in the earlier versions has been replaced by the improved Modern-Era Retrospective analysis for Research and Applications, Version 2 (MERRA-2), model. An aerosol scattering ratio of 1.01 ± 0.01 is now explicitly used for the calibration altitude. These modifications lead to globally revised calibration coefficients which are, on average, 2-3 % lower than in previous data releases. Further, the new calibration procedure is shown to eliminate biases at high altitudes that were present in earlier versions and consequently leads to an improved representation of
Calibration issues for neutron diagnostics
International Nuclear Information System (INIS)
Sadler, G.J.; Adams, J.M.; Barnes, C.W.
The performance of diagnostic systems are limited by their weakest constituents, including their calibration issues. Neutron diagnostics are notorious for problems encountered while determining their absolute calibrations, due mainly to the nature of the neutron transport problem. In order to facilitate the determination of an accurate and precise calibration, the diagnostic design should be such as to minimize the scattered neutron flux. ITER will use a comprehensive set of neutron diagnostics--comprising radial and vertical neutron cameras, neutron spectrometers, a neutron activation system and internal and external fission chambers--to provide accurate measurements of fusion power and power densities as a function of time. The calibration of such an important diagnostic system merits careful consideration. Some thoughts have already been given to this subject during the conceptual design phase in relation to the time-integrated neutron activation and time-dependent neutron yield monitors. However, no overall calibration strategy has been worked out so far. This paper represents a first attempt to address this vital issue. Experience gained from present large tokamaks (JET, TFTR and JT60U) and proposals for ITER are reviewed. The need to use a 14-MeV neutron generator as opposed to radioactive sources for in-situ calibration of D-T diagnostics will be stressed. It is clear that the overall absolute determination of fusion power will have to rely on a combination of nuclear measuring techniques, for which the provision of accurate and independent calibrations will constitute an ongoing process as ITER moves from one phase of operation to the next
40 CFR 92.116 - Engine output measurement system calibrations.
... manufacturer's data, actual measurement, or the value recorded from the previous calibration used for this... load-cell or transfer standard may be used to verify the in-use torque measurement system. (i) The... spaced torque values as indicated by the master load-cell for each in-use range used. (v) The in-use...
Gearbox Reliability Collaborative High Speed Shaft Tapered Roller Bearing Calibration
Energy Technology Data Exchange (ETDEWEB)
Keller, J.; Guo, Y.; McNiff, B.
The National Renewable Energy Laboratory (NREL) Gearbox Reliability Collaborative (GRC) is a project investigating gearbox reliability primarily through testing and modeling. Previous dynamometer testing focused upon acquiring measurements in the planetary section of the test gearbox. Prior to these tests, the strain gages installed on the planetary bearings were calibrated in a load frame.
CAMAC-controlled calibration system for nuclear reactor instruments
International Nuclear Information System (INIS)
McDowell, W.P.; Cornella, R.J.
The hardware and the software which have been developed to implement a nuclear instrument calibration system for the Argonne National Laboratory ZPR-VI and ZPR-IX reactor complex are described. The system is implemented using an SEL-840 computer with its associated CAMAC crates and a hardware interface to generate input parameters and measure the required outputs on the instrument under test. Both linear and logarithmic instruments can be calibrated by the system and output parameters can be measured at various automatically selected values of ac line voltage. A complete report on each instrument is printed as a result of the calibration and out-of-tolerance readings are flagged. Operator interface is provided by a CAMAC-controlled Hazeltine terminal. The terminal display leads the operator through the complete calibration procedure. This computer-controlled system is a significant improvement over previously used methods of calibrating nuclear instruments since it reduces reactor downtime and allows rapid detection of long-term changes in instrument calibration
The calibration procedures in the Studsvik standardized personnel dosimetry system
International Nuclear Information System (INIS)
Widell, C.O.
Every large nuclear installation in Sweden reads its own personnel TLDs. In order to supervise this decentralized reading of dose meters, the TLD readers are connected by telephone lines to a central computer for dose registration. This computer is used both for registering the personnel doses and for checking the TLD readers. This checking is performed by the use of pre-irradiated calibration dose meters which are always used when a batch of personnel dose meters are read. The pre-irradiated dose meters are either irradiated using 137 Cs to various doses up to 100mSv(10000mrem) or using a 90 Sr source in a reference dose irradiator to a dose equal to 3mSv(300mrem) from a 137 Cs source. The results from the reading of the pre-irradiated dose meters are processed by the computer and a calibration factor is calculated. The calibration factor is automatically used to calculate the doses to the personnel TLD's. However, if the calibration factor deviates by more than 10% from the previously used factor, this fact is shown to the operator - who then has to decide what calibration factor is going to be used. This calibration and supervisory procedure together with the safety interlocks in the TLD readers has resulted in a very reliable and accurate dosimetry system. (author)
Cosmic CARNage I: on the calibration of galaxy formation models
Knebe, Alexander; Pearce, Frazer R.; Gonzalez-Perez, Violeta; Thomas, Peter A.; Benson, Andrew; Asquith, Rachel; Blaizot, Jeremy; Bower, Richard; Carretero, Jorge; Castander, Francisco J.; Cattaneo, Andrea; Cora, Sofía A.; Croton, Darren J.; Cui, Weiguang; Cunnama, Daniel; Devriendt, Julien E.; Elahi, Pascal J.; Font, Andreea; Fontanot, Fabio; Gargiulo, Ignacio D.; Helly, John; Henriques, Bruno; Lee, Jaehyun; Mamon, Gary A.; Onions, Julian; Padilla, Nelson D.; Power, Chris; Pujol, Arnau; Ruiz, Andrés N.; Srisawat, Chaichalit; Stevens, Adam R. H.; Tollet, Edouard; Vega-Martínez, Cristian A.; Yi, Sukyoung K.
We present a comparison of nine galaxy formation models, eight semi-analytical, and one halo occupation distribution model, run on the same underlying cold dark matter simulation (cosmological box of comoving width 125h-1 Mpc, with a dark-matter particle mass of 1.24 × 109h-1M⊙) and the same merger trees. While their free parameters have been calibrated to the same observational data sets using two approaches, they nevertheless retain some `memory' of any previous calibration that served as the starting point (especially for the manually tuned models). For the first calibration, models reproduce the observed z = 0 galaxy stellar mass function (SMF) within 3σ. The second calibration extended the observational data to include the z = 2 SMF alongside the z ˜ 0 star formation rate function, cold gas mass, and the black hole-bulge mass relation. Encapsulating the observed evolution of the SMF from z = 2 to 0 is found to be very hard within the context of the physics currently included in the models. We finally use our calibrated models to study the evolution of the stellar-to-halo mass (SHM) ratio. For all models, we find that the peak value of the SHM relation decreases with redshift. However, the trends seen for the evolution of the peak position as well as the mean scatter in the SHM relation are rather weak and strongly model dependent. Both the calibration data sets and model results are publicly available.
Online Sensor Calibration Assessment in Nuclear Power Systems
International Nuclear Information System (INIS)
Coble, Jamie B.; Ramuhalli, Pradeep; Meyer, Ryan M.; Hashemian, Hash
Safe, efficient, and economic operation of nuclear systems (nuclear power plants, fuel fabrication and storage, used fuel processing, etc.) relies on transmission of accurate and reliable measurements. During operation, sensors degrade due to age, environmental exposure, and maintenance interventions. Sensor degradation can affect the measured and transmitted signals, including sensor failure, signal drift, sensor response time, etc. Currently, periodic sensor recalibration is performed to avoid these problems. Sensor recalibration activities include both calibration assessment and adjustment (if necessary). In nuclear power plants, periodic recalibration of safety-related sensors is required by the plant technical specifications. Recalibration typically occurs during refueling outages (about every 18 to 24 months). Non-safety-related sensors also undergo recalibration, though not as frequently. However, this approach to maintaining sensor calibration and performance is time-consuming and expensive, leading to unnecessary maintenance, increased radiation exposure to maintenance personnel, and potential damage to sensors. Online monitoring (OLM) of sensor performance is a non-invasive approach to assess instrument calibration. OLM can mitigate many of the limitations of the current periodic recalibration practice by providing more frequent assessment of calibration and identifying those sensors that are operating outside of calibration tolerance limits without removing sensors or interrupting operation. This can support extended operating intervals for unfaulted sensors and target recalibration efforts to only degraded sensors
How to calibrate Grenz-beams in clinical practice?
Energy Technology Data Exchange (ETDEWEB)
Schaeken, B [Algemeen Ziekenhius Middelheim, Antwerp (Belgium); Bressers, E [Virga jesse Ziekenhius, Hasselt (Belgium)
In recent years, considerable efforts have been spent improving the precision and consistency in the whole process of calibration of high energy photon and electron beams (national protocols, primary calibration facilities ....). The reading in air of 5 different ionisation chambers (NE2532, NE2536, NE2571, PTWM23342, Markus) in an X-ray beam (RT50, HVL=0.35 mm Al) has been compared. Ali NE chambers were provided with a calibration factor Nk, the PTW chamber was directly calibrated in dose water ND,W. The polarisation and recombination effects were measured. In our reference field (ssd=4cm, field diameter 40 mm), the readings in air for the dedicated plan parallel chambers deviated by not more than 8%. The measurements with the NE2571 chamber did not correspond very well with the other measurements. For the equipment in our hospital, the dose rate in air for the reference field was measured from 1971 on and found to be very stable: 17.36 Gy/min (0.48) (1sd). An attempt was made to measure the BSF for the field defining cones used in clinical practice using a Markus plane parallel chamber, but the resulting BSF did not correspond to those reported in BJR/suppl. 17. Special attention has been be paid to the calibration of beams with field size comparable to the dimension of the chamber window- chamber body.
FTIR Calibration Methods and Issues
Perron, Gaetan
Over the past 10 years, several space-borne FTIR missions were launched for atmospheric research, environmental monitoring and meteorology. One can think of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) launched by the European Space Agency, the Atmospheric Chemistry Experiment (ACE) launched by the Canadian Space Agency, the Tropospheric Emission Spectrometer (TES) launched by NASA and the Infrared Atmospheric Sounding Interferometer (IASI) launched by Eumetsat in Europe. Others are near to be launched, namely the Cross-track Infrared Sounder (CrIS) from the Integrated Program Of- fice in the United States and the Thermal And Near infrared Sensor for carbon Observation (TANSO) from the Japan Aerospace Exploration Agency. Moreover, several missions under definition foresee the use of this technology as sensor, e.g. Meteosat Third Generation (MTG), Eumetsat Polar System (EPS) and the Premier mission, one of the six candidates of the next ESA Earth Explorer Core Mission. In order to produce good quality products, calibration is essential. Calibrated data is the output of three main sub-systems that are tightly coupled: the instrument, the calibration targets and the level 1B processor. Calibration requirements must be carefully defined and propagated to each sub-system. Often, they are carried out by different parties which add to the complexity. Under budget and schedule pressure, some aspects are sometimes neglected and jeopardized final quality. For space-borne FTIR, level 1B outputs are spectra that are radiometrically, spectrally calibrated and geolocated. Radiometric calibration means to assign an intensity value in units to the y-axis. Spectral calibration means to assign to the x-axis the proper frequency value in units. Finally, geolocated means to assign a target position over the earth geoid i.e. longitude, latitude and altitude. This paper will present calibration methods and issues related to space-borne FTIR missions, e.g. two
Calibration, monitoring, and control of complex detector systems
International Nuclear Information System (INIS)
Breidenbach, M.
LEP detectors will probably be complex devices having tens of subsystems; some subsystems having perhaps tens of thousands of channels. Reasonable design goals for such a detector will include economic use of money and people, rapid and reliable calibration and monitoring of the detector, and simple control and operation of the device. The synchronous operation of an e + e - storage ring, coupled with its relatively low interaction rate, allow the design of simple circuits for time and charge measurements. These circuits, and more importantly, the basic detector channels, can usually be tested and calibrated by signal injection into the detector. Present detectors utilize semi-autonomous controllers which collect such calibration data and calculate statistics as well as control sparse data scans. Straightforward improvements in programming technology should move the entire calibration into these local controllers, so that calibration and testing time will be a constant independent of the number of channels in a system. Considerable programming effort may be saved by emphasizing the similarities of the subsystems, so that the subsystems can be described by a reasonable database and general purpose calibration and test routines can be used. Monitoring of the apparatus will probably continue to be of two classes: 'passive' histogramming of channel occupancies and other more complex combinations of the data; and 'active' injection of test patterns and calibration signals during a run. The relative importance of active monitoring will increase for the low data rates expected off resonances at high s. Experience at SPEAR and PEP is used to illustrate these approaches. (Auth.)
Calibration, Monitoring, and Control of Complex Detector Systems
Breidenbach, M.
LEP Detectors will probably be complex devices having tens of subsystems; some subsystems having perhaps tens of thousands of channels. Reasonable design goals for such a detector will include economic use of money and people, rapid and reliable calibration and monitoring of the detector, and simple control and operation of the device. The synchronous operation of an e+e- storage ring, coupled with its relatively low interaction rate, allow the design of simple circuits for time and charge measurements. These circuits, and more importantly, the basic detector channels, can usually be tested and calibrated by signal injection into the detector. Present detectors utilize semi-autonomous controllers which collect such calibration data and calculate statistics as well as control sparse data scans. Straightforward improvements in programming technology should move the entire calibration into these local controllers, so that calibration and testing time will be a constant independent of the number of channels in a system. Considerable programming effort may be saved by emphasizing the similarities of the subsystems, so that the subsystems can be described by a reasonable database and general purpose calibration and test routines can be used. Monitoring of the apparatus will probably continue to be of two classes: "passive" histogramming of channel occupancies and other more complex combinations of the data; and "active" injection of test patterns and calibration signals during a run. The relative importance of active monitoring will increase for the low data rates expected off resonances at high s. Experience at SPEAR and PEP is used to illustrate these approaches.
Automatic calibration of gamma spectrometers
International Nuclear Information System (INIS)
Tluchor, D.; Jiranek, V.
The principle is described of energy calibration of the spectrometric path based on the measurement of the standard of one radionuclide or a set of them. The entire computer-aided process is divided into three main steps, viz.: the insertion of the calibration standard by the operator; the start of the calibration program; energy calibration by the computer. The program was selected such that the spectrum identification should not depend on adjustment of the digital or analog elements of the gamma spectrometric measuring path. The ECL program is described for automatic energy calibration as is its control, the organization of data file ECL.DAT and the necessary hardware support. The computer-multichannel analyzer communication was provided using an interface pair of Canberra 8673V and Canberra 8573 operating in the RS-422 standard. All subroutines for communication with the multichannel analyzer were written in MACRO 11 while the main program and the other subroutines were written in FORTRAN-77. (E.J.). 1 tab., 4 refs
Calibration of the SNO+ experiment
Maneira, J.; Falk, E.; Leming, E.; Peeters, S.; SNO+ Collaboration.
The main goal of the SNO+ experiment is to perform a low-background and high-isotope-mass search for neutrinoless double-beta decay, employing 780 tonnes of liquid scintillator loaded with tellurium, in its initial phase at 0.5% by mass for a total mass of 1330 kg of 130Te. The SNO+ physics program includes also measurements of geo- and reactor neutrinos, supernova and solar neutrinos. Calibrations are an essential component of the SNO+ data-taking and analysis plan. The achievement of the physics goals requires both an extensive and regular calibration. This serves several goals: the measurement of several detector parameters, the validation of the simulation model and the constraint of systematic uncertainties on the reconstruction and particle identification algorithms. SNO+ faces stringent radiopurity requirements which, in turn, largely determine the materials selection, sealing and overall design of both the sources and deployment systems. In fact, to avoid frequent access to the inner volume of the detector, several permanent optical calibration systems have been developed and installed outside that volume. At the same time, the calibration source internal deployment system was re-designed as a fully sealed system, with more stringent material selection, but following the same working principle as the system used in SNO. This poster described the overall SNO+ calibration strategy, discussed the several new and innovative sources, both optical and radioactive, and covered the developments on source deployment systems.
Calibration strategies for the Cherenkov Telescope Array
Gaug, M.; Berge, D.; Daniel, M.; Doro, M.; Förster, A.; Hofmann, W.; Maccarone, M.C.; Parsons, D.; de los Reyes Lopez, R.; van Eldik, C.
The Central Calibration Facilities workpackage of the Cherenkov Telescope Array (CTA) observatory for very high energy gamma ray astronomy defines the overall calibration strategy of the array, develops dedicated hardware and software for the overall array calibration and coordinates the calibration
Consequences of Secondary Calibrations on Divergence Time Estimates.
Directory of Open Access Journals (Sweden)
John J Schenk
Full Text Available Secondary calibrations (calibrations based on the results of previous molecular dating studies are commonly applied in divergence time analyses in groups that lack fossil data; however, the consequences of applying secondary calibrations in a relaxed-clock approach are not fully understood. I tested whether applying the posterior estimate from a primary study as a prior distribution in a secondary study results in consistent age and uncertainty estimates. I compared age estimates from simulations with 100 randomly replicated secondary trees. On average, the 95% credible intervals of node ages for secondary estimates were significantly younger and narrower than primary estimates. The primary and secondary age estimates were significantly different in 97% of the replicates after Bonferroni corrections. Greater error in magnitude was associated with deeper than shallower nodes, but the opposite was found when standardized by median node age, and a significant positive relationship was determined between the number of tips/age of secondary trees and the total amount of error. When two secondary calibrated nodes were analyzed, estimates remained significantly different, and although the minimum and median estimates were associated with less error, maximum age estimates and credible interval widths had greater error. The shape of the prior also influenced error, in which applying a normal, rather than uniform, prior distribution resulted in greater error. Secondary calibrations, in summary, lead to a false impression of precision and the distribution of age estimates shift away from those that would be inferred by the primary analysis. These results suggest that secondary calibrations should not be applied as the only source of calibration in divergence time analyses that test time-dependent hypotheses until the additional error associated with secondary calibrations is more properly modeled to take into account increased uncertainty in age estimates.
Using Active Learning for Speeding up Calibration in Simulation Models.
Cevik, Mucahit; Ergun, Mehmet Ali; Stout, Natasha K; Trentham-Dietz, Amy; Craven, Mark; Alagoz, Oguzhan
Most cancer simulation models include unobservable parameters that determine disease onset and tumor growth. These parameters play an important role in matching key outcomes such as cancer incidence and mortality, and their values are typically estimated via a lengthy calibration procedure, which involves evaluating a large number of combinations of parameter values via simulation. The objective of this study is to demonstrate how machine learning approaches can be used to accelerate the calibration process by reducing the number of parameter combinations that are actually evaluated. Active learning is a popular machine learning method that enables a learning algorithm such as artificial neural networks to interactively choose which parameter combinations to evaluate. We developed an active learning algorithm to expedite the calibration process. Our algorithm determines the parameter combinations that are more likely to produce desired outputs and therefore reduces the number of simulation runs performed during calibration. We demonstrate our method using the previously developed University of Wisconsin breast cancer simulation model (UWBCS). In a recent study, calibration of the UWBCS required the evaluation of 378 000 input parameter combinations to build a race-specific model, and only 69 of these combinations produced results that closely matched observed data. By using the active learning algorithm in conjunction with standard calibration methods, we identify all 69 parameter combinations by evaluating only 5620 of the 378 000 combinations. Machine learning methods hold potential in guiding model developers in the selection of more promising parameter combinations and hence speeding up the calibration process. Applying our machine learning algorithm to one model shows that evaluating only 1.49% of all parameter combinations would be sufficient for the calibration. © The Author(s) 2015.
In-Flight Calibration Processes for the MMS Fluxgate Magnetometers
Bromund, K. R.; Leinweber, H. K.; Plaschke, F.; Strangeway, R. J.; Magnes, W.; Fischer, D.; Nakamura, R.; Anderson, B. J.; Russell, C. T.; Baumjohann, W.;
The calibration effort for the Magnetospheric Multiscale Mission (MMS) Analog Fluxgate (AFG) and DigitalFluxgate (DFG) magnetometers is a coordinated effort between three primary institutions: University of California, LosAngeles (UCLA); Space Research Institute, Graz, Austria (IWF); and Goddard Space Flight Center (GSFC). Since thesuccessful deployment of all 8 magnetometers on 17 March 2015, the effort to confirm and update the groundcalibrations has been underway during the MMS commissioning phase. The in-flight calibration processes evaluatetwelve parameters that determine the alignment, orthogonalization, offsets, and gains for all 8 magnetometers usingalgorithms originally developed by UCLA and the Technical University of Braunschweig and tailored to MMS by IWF,UCLA, and GSFC. We focus on the processes run at GSFC to determine the eight parameters associated with spin tonesand harmonics. We will also discuss the processing flow and interchange of parameters between GSFC, IWF, and UCLA.IWF determines the low range spin axis offsets using the Electron Drift Instrument (EDI). UCLA determines the absolutegains and sensor azimuth orientation using Earth field comparisons. We evaluate the performance achieved for MMS andgive examples of the quality of the resulting calibrations.
Calibration pipeline for VIR data
Carraro, F.; Fonte, S.; Coradini, A.; Filacchione, G.; de Sanctis, M. C.; Ammannito, E.; Capria, M. T.; Cartacci, M.; Noschese, R.; Tosi, F.; Capaccioni, F.
During the second quarter of 2011 VIR-MS (VIS and IR Mapping Spectrometer) [1] aboard Dawn mission [2] has approached Vesta in order to start a long period of acquisitions that will end at the beginning of 2012. Data acquired by each instrument always require a calibration process in order to remove all the instrument effects that could affect the scientific evaluations and analysis. VIR-MS instrument team has realized a calibration pipeline which has the goal of producing calibrated (1b level) data starting from the raw (1a level) ones. The other goal of the tool has been the check of the goodness of acquired data by means of the evaluation of a series of minimum requisites of each data file, such as the percentage of the saturated pixels, the presence of spikes or the mean S/N ratio of each qube.
Reliability-Based Code Calibration
DEFF Research Database (Denmark)
Faber, M.H.; Sørensen, John Dalsgaard
The present paper addresses fundamental concepts of reliability based code calibration. First basic principles of structural reliability theory are introduced and it is shown how the results of FORM based reliability analysis may be related to partial safety factors and characteristic values....... Thereafter the code calibration problem is presented in its principal decision theoretical form and it is discussed how acceptable levels of failure probability (or target reliabilities) may be established. Furthermore suggested values for acceptable annual failure probabilities are given for ultimate...... and serviceability limit states. Finally the paper describes the Joint Committee on Structural Safety (JCSS) recommended procedure - CodeCal - for the practical implementation of reliability based code calibration of LRFD based design codes....
Radiation protection dosimetry and calibrations
International Nuclear Information System (INIS)
Verhavere, Ph.
At the SCK-CEN different specialised services are delivered for a whole range of external and internal customers in the radiation protection area. For the expertise group of radiation protection dosimetry and calibrations, these services are organized in four different laboratories: dosimetry, anthropogammametry, nuclear calibrations and non-nuclear calibrations. The services are given by a dedicated technical staff who has experience in the handling of routine and specialised cases. The scientific research that is performed by the expertise group makes sure that state-of-the-art techniques are being used, and that constant improvements and developments are implemented. Quality Assurance is an important aspect for the different services, and accreditation according national and international standards is achieved for all laboratories
XRD alignment, calibration and performance
International Nuclear Information System (INIS)
Davy, L.
Full text: The quality of any diffractometer system is very much dependent on the alignment, calibration and performance. The three subjects are very much related. Firstly, you must know how to carry out the full diffractometer alignment. XRD alignment is easy once you know how. The presentation will show you step by step to carry out the full alignment. Secondly, you need to know how to calibrate the diffractometer system. The presentation will show you how to calibrate the goniometer, detector etc. Thirdly, to prove the system is working within the manufacturer specification. The presentation will show you how to carry out the resolution, reproducibility and linearity test. Copyright (2002) Australian X-ray Analytical Association Inc
Upgrading the Medical Physics Calibration Laboratory Towards ISO/IEC 17025: Radiation Standards and Calibration in Diagnostic Radiology
International Nuclear Information System (INIS)
Asmaliza Hashim; Muhammad Jamal Md Isa; Abd Aziz Mhd Ramli; Wan Hazlinda Ismail; Norhayati Abdullah; Shahrul Azlan Azizan; Siti Sara Deraman; Nor Azlin Azraai; Md Khairusalih Md Zin
Calibration of quality control (QC) test tools used in diagnostic radiology is legally required under the Ministry of Health (MOH) requirement. The Medical Physics Calibration Laboratory of the Malaysian Nuclear Agency is the national focal point for the calibration of quality control test tools used in diagnostic radiology. The Medical Physics Calibration Laboratory has measurement traceability to primary standard dosimetry laboratory (Physikalisch-Technische Bundesanstalt (PTB)), thus providing an interface between the primary standard dosimetry laboratory and Malaysian hospitals, clinics and license class H holder. The Medical Physics Calibration Laboratory facility is comprised of a constant potential x-ray system with a capability of 160 kV tube and a series of reference and working standard ion chambers. The stability of reference and working standard ion chambers was measured using strontium-90. Dosimetric instruments used in diagnostic radiology is calibrated in terms of air kerma to comply with an International Code of Practices of dosimetry for example IAEA's Technical Report Series number 457. The new series of standard radiation qualities was established based on ISO/IEC 61267. The measurement of beam homogeneity was measured using film and ion chamber to define the field size at certain distance and kV output was measured using the spectrometer and non-invasive kVp meter. The uncertainties measurement was determined with expended uncertainties to a level of confidence of approximately 95% (coverage factor k=2). This paper describes the available facility and the effort of the Medical Physics Calibration Laboratory to upgrade the laboratory towards ISO/IEC 17025. (author)
Using a cloud to replenish parched groundwater modeling efforts.
Hunt, Randall J; Luchette, Joseph; Schreuder, Willem A; Rumbaugh, James O; Doherty, John; Tonkin, Matthew J; Rumbaugh, Douglas B
Groundwater models can be improved by introduction of additional parameter flexibility and simultaneous use of soft-knowledge. However, these sophisticated approaches have high computational requirements. Cloud computing provides unprecedented access to computing power via the Internet to facilitate the use of these techniques. A modeler can create, launch, and terminate "virtual" computers as needed, paying by the hour, and save machine images for future use. Such cost-effective and flexible computing power empowers groundwater modelers to routinely perform model calibration and uncertainty analysis in ways not previously possible.
Using a cloud to replenish parched groundwater modeling efforts
Hunt, Randall J.; Luchette, Joseph; Schreuder, Willem A.; Rumbaugh, James O.; Doherty, John; Tonkin, Matthew J.; Rumbaugh, Douglas B.
Groundwater models can be improved by introduction of additional parameter flexibility and simultaneous use of soft-knowledge. However, these sophisticated approaches have high computational requirements. Cloud computing provides unprecedented access to computing power via the Internet to facilitate the use of these techniques. A modeler can create, launch, and terminate "virtual" computers as needed, paying by the hour, and save machine images for future use. Such cost-effective and flexible computing power empowers groundwater modelers to routinely perform model calibration and uncertainty analysis in ways not previously possible.
Books average previous decade of economic misery.
Bentley, R Alexander; Acerbi, Alberto; Ormerod, Paul; Lampos, Vasileios
For the 20(th) century since the Depression, we find a strong correlation between a 'literary misery index' derived from English language books and a moving average of the previous decade of the annual U.S. economic misery index, which is the sum of inflation and unemployment rates. We find a peak in the goodness of fit at 11 years for the moving average. The fit between the two misery indices holds when using different techniques to measure the literary misery index, and this fit is significantly better than other possible correlations with different emotion indices. To check the robustness of the results, we also analysed books written in German language and obtained very similar correlations with the German economic misery index. The results suggest that millions of books published every year average the authors' shared economic experiences over the past decade.
Books Average Previous Decade of Economic Misery
Bentley, R. Alexander; Acerbi, Alberto; Ormerod, Paul; Lampos, Vasileios
For the 20th century since the Depression, we find a strong correlation between a 'literary misery index' derived from English language books and a moving average of the previous decade of the annual U.S. economic misery index, which is the sum of inflation and unemployment rates. We find a peak in the goodness of fit at 11 years for the moving average. The fit between the two misery indices holds when using different techniques to measure the literary misery index, and this fit is significantly better than other possible correlations with different emotion indices. To check the robustness of the results, we also analysed books written in German language and obtained very similar correlations with the German economic misery index. The results suggest that millions of books published every year average the authors' shared economic experiences over the past decade. PMID:24416159
Optimal Effort in Consumer Choice : Theory and Experimental Evidence for Binary Choice
Conlon, B.J.; Dellaert, B.G.C.; van Soest, A.H.O.
This paper develops a theoretical model of optimal effort in consumer choice.The model extends previous consumer choice models in that the consumer not only chooses a product, but also decides how much effort to apply to a given choice problem.The model yields a unique optimal level of effort, which
CryoSat/SIRAL Cal1 Calibration Orbits
Scagliola, Michele; Fornari, Marco; Bouffard, Jerome; Parrinello, Tommaso
The main payload of CryoSat is a Ku band pulsewidth limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for SAR processing. This allows to reach an along track resolution that is significantly improved with respect to traditional pulse-width limited altimeters. Due to the fact that SIRAL is a phase coherent pulse-width limited radar altimeter, a proper calibration approach has been developed. In fact, not only corrections for transfer function, gain and instrument path delay have to be computed (as in previous altimeters), but also corrections for phase (SAR/SARIn) and phase difference between the two receiving chains (SARIN only). Recalling that the CryoSat's orbit has a high inclination of 92° and it is non-sun-synchronous, the temperature of the SIRAL changes continuously along the orbit with a period of about 480 days and it is also function of the ascending/descending passes. By analysis of the CAL1 calibration corrections, it has been verified that the internal path delay and the instrument gain variation measured on the SIRAL are affected by the thermal status of the instrument and as a consequence they are expected to vary along the orbit. In order to gain knowledge on the calibration corrections (i.e. the instrument behavior) as function of latitude and temperature, it has been planned to command a few number of orbits where only CAL1 calibration acquisitions are continuously performed. The analysis of the CAL1 calibration corrections produced along the Calibration orbits can be also useful to verify whether the current calibration plan is able to provide sufficiently accurate corrections for the instrument acquisitions at any latitude. In 2016, the CryoSat/SIRAL Cal1 Calibration Orbits have been commanded two times, a first time the 20th of July 2016 and a second time the 24th of November 2016, and they
Measuring collections effort improves cash performance.
Shutts, Joe
Having a satisfied work force can lead to an improved collections effort. Hiring the right people and training them ensures employee engagement. Measuring collections effort and offering incentives is key to revenue cycle success.
Performance standard for dose Calibrator
Darmawati, S
Dose calibrator is an instrument used in hospitals to determine the activity of radionuclide for nuclear medicine purposes. International Electrotechnical Commission (IEC) has published IEC 1303:1994 standard that can be used as guidance to test the performance of the instrument. This paper briefly describes content of the document,as well as explains the assessment that had been carried out to test the instrument accuracy in Indonesia through intercomparison measurement.Its is suggested that hospitals acquire a medical physicist to perform the test for its dose calibrator. The need for performance standard in the form of Indonesia Standard is also touched.
Model Calibration in Option Pricing
Directory of Open Access Journals (Sweden)
Andre Loerx
Full Text Available We consider calibration problems for models of pricing derivatives which occur in mathematical finance. We discuss various approaches such as using stochastic differential equations or partial differential equations for the modeling process. We discuss the development in the past literature and give an outlook into modern approaches of modelling. Furthermore, we address important numerical issues in the valuation of options and likewise the calibration of these models. This leads to interesting problems in optimization, where, e.g., the use of adjoint equations or the choice of the parametrization for the model parameters play an important role.
Instrument Calibration and Certification Procedure
Energy Technology Data Exchange (ETDEWEB)
Davis, R. Wesley [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
The Amptec 640SL-2 is a 4-wire Kelvin failsafe resistance meter, designed to reliably use very low-test currents for its resistance measurements. The 640SL-1 is a 2-wire version, designed to support customers using the Reynolds Industries type 311 connector. For both versions, a passive (analog) dual function DC Milliameter/Voltmeter allows the user to verify the actual 640SL output current level and the open circuit voltage on the test leads. This procedure includes tests of essential performance parameters. Any malfunction noticed during calibration, whether specifically tested for or not, shall be corrected before calibration continues or is completed.
NIST display colorimeter calibration facility
Brown, Steven W.; Ohno, Yoshihiro
A facility has been developed at the National Institute of Standards and Technology (NIST) to provide calibration services for color-measuring instruments to address the need for improving and certifying the measurement uncertainties of this type of instrument. While NIST has active programs in photometry, flat panel display metrology, and color and appearance measurements, these are the first services offered by NIST tailored to color-measuring instruments for displays. An overview of the facility, the calibration approach, and associated uncertainties are presented. Details of a new tunable colorimetric source and the development of new transfer standard instruments are discussed.
Tank calibration; Arqueacao de tanques
Energy Technology Data Exchange (ETDEWEB)
Chan, Ana [PETROBRAS S.A., Rio de Janeiro, RJ (Brazil)
This work relates the analysis of the norms ISO (International Organization for Standardization) for calibration of vertical cylindrical tanks used in fiscal measurement, established on Joint Regulation no 1 of June 19, 2000 between the ANP (National Agency of Petroleum) and the INMETRO (National Institute of Metrology, Normalization and Industrial Quality). In this work a comparison between norms ISO and norms published by the API (American Petroleum Institute) and the IP (Institute of Petroleum) up to 2001 was made. It was concluded that norms ISO are wider than norms API, IP, and INMETRO methods in the calibration of vertical cylindrical tanks. (author)
Gearbox Reliability Collaborative Gearbox 3 Planet Bearing Calibration
Energy Technology Data Exchange (ETDEWEB)
Keller, Jonathan [National Renewable Energy Lab. (NREL), Golden, CO (United States)
The Gearbox Reliability Collaborative gearbox was redesigned to improve its load-sharing characteristics and predicted fatigue life. The most important aspect of the redesign was to replace the cylindrical roller bearings with preloaded tapered roller bearings in the planetary section. Similar to previous work, the strain gages installed on the planet tapered roller bearings were calibrated in a load frame. This report describes the calibration tests and provides the factors necessary to convert the measured units from dynamometer testing to bearing loads, suitable for comparison to engineering models.
SU-E-J-221: Advantages of a New Surface Imaging Calibration Method for SRS Treatments
International Nuclear Information System (INIS)
Paxton, A; Manger, R; Pawlicki, T; Kim, G
Purpose: The present calibration method used for the AlignRT surface imaging system relies on the placement of a calibration plate at the linac isocenter using isocenter surrogates (crosshairs, room lasers, etc.). This work investigated the potential advantages of a new calibration method that shifts the AlignRT isocenter to be coincident with the linac MV beam isocenter. Methods: To quantify the potential uncertainties associated with the present calibration method for SRS treatments, the calibration plate was intentionally shifted away from isocenter +/−3mm in the longitudinal and lateral directions and +/−1mm in the longitudinal, lateral, and vertical directions. A head phantom was placed in a mock SRS treatment position and monitored with the AlignRT system. The AlignRT-indicated offsets were recorded at 270, 315, 0, 45, and 90° couch angles for each intentional calibration misalignment. The new isocenter calibration was applied after each misalignment, and the measurements were repeated and compared to the previous results. Results: With intentional longitudinal and lateral shifts of +/−3mm and +/−1mm in the calibration plate, the average indicated offsets at couch rotations of +/−90° were 4.3mm and 1.6mm, respectively. This was in agreement with the theoretical offset of sqrt(2)*(intentional shift of the calibration plate). Since vertical shifts were along the rotation axis of the couch, these shifts had little effect on the offsets with changing couch angle. When the new calibration was applied, the indicated offsets were all within 0.5mm for all couch angles. These offsets were in agreement with the known magnitude of couch walkout. Conclusion: The potential pitfalls of the present calibration method have been established, and the advantages of the new calibration method have been demonstrated. This new calibration method effectively removes the potential miscalibration artifacts of the present calibration method, giving the AlignRT user more
Underestimation of Severity of Previous Whiplash Injuries
Naqui, SZH; Lovell, SJ; Lovell, ME
INTRODUCTION We noted a report that more significant symptoms may be expressed after second whiplash injuries by a suggested cumulative effect, including degeneration. We wondered if patients were underestimating the severity of their earlier injury. PATIENTS AND METHODS We studied recent medicolegal reports, to assess subjects with a second whiplash injury. They had been asked whether their earlier injury was worse, the same or lesser in severity. RESULTS From the study cohort, 101 patients (87%) felt that they had fully recovered from their first injury and 15 (13%) had not. Seventy-six subjects considered their first injury of lesser severity, 24 worse and 16 the same. Of the 24 that felt the violence of their first accident was worse, only 8 had worse symptoms, and 16 felt their symptoms were mainly the same or less than their symptoms from their second injury. Statistical analysis of the data revealed that the proportion of those claiming a difference who said the previous injury was lesser was 76% (95% CI 66–84%). The observed proportion with a lesser injury was considerably higher than the 50% anticipated. CONCLUSIONS We feel that subjects may underestimate the severity of an earlier injury and associated symptoms. Reasons for this may include secondary gain rather than any proposed cumulative effect. PMID:18201501
[Electronic cigarettes - effects on health. Previous reports].
Napierała, Marta; Kulza, Maksymilian; Wachowiak, Anna; Jabłecka, Katarzyna; Florek, Ewa
Currently very popular in the market of tobacco products have gained electronic cigarettes (ang. E-cigarettes). These products are considered to be potentially less harmful in compared to traditional tobacco products. However, current reports indicate that the statements of the producers regarding to the composition of the e- liquids not always are sufficient, and consumers often do not have reliable information on the quality of the product used by them. This paper contain a review of previous reports on the composition of e-cigarettes and their impact on health. Most of the observed health effects was related to symptoms of the respiratory tract, mouth, throat, neurological complications and sensory organs. Particularly hazardous effects of the e-cigarettes were: pneumonia, congestive heart failure, confusion, convulsions, hypotension, aspiration pneumonia, face second-degree burns, blindness, chest pain and rapid heartbeat. In the literature there is no information relating to passive exposure by the aerosols released during e-cigarette smoking. Furthermore, the information regarding to the use of these products in the long term are not also available.
Dissociating variability and effort as determinants of coordination.
Directory of Open Access Journals (Sweden)
Ian O'Sullivan
Full Text Available When coordinating movements, the nervous system often has to decide how to distribute work across a number of redundant effectors. Here, we show that humans solve this problem by trying to minimize both the variability of motor output and the effort involved. In previous studies that investigated the temporal shape of movements, these two selective pressures, despite having very different theoretical implications, could not be distinguished; because noise in the motor system increases with the motor commands, minimization of effort or variability leads to very similar predictions. When multiple effectors with different noise and effort characteristics have to be combined, however, these two cost terms can be dissociated. Here, we measure the importance of variability and effort in coordination by studying how humans share force production between two fingers. To capture variability, we identified the coefficient of variation of the index and little fingers. For effort, we used the sum of squared forces and the sum of squared forces normalized by the maximum strength of each effector. These terms were then used to predict the optimal force distribution for a task in which participants had to produce a target total force of 4-16 N, by pressing onto two isometric transducers using different combinations of fingers. By comparing the predicted distribution across fingers to the actual distribution chosen by participants, we were able to estimate the relative importance of variability and effort of 1:7, with the unnormalized effort being most important. Our results indicate that the nervous system uses multi-effector redundancy to minimize both the variability of the produced output and effort, although effort costs clearly outweighed variability costs.
Ten years of a National Service of Dosimetric calibration at radiation protection
International Nuclear Information System (INIS)
Morales, J.A.; Jova, L.; Hernandez, E.; Campa, R.; Walwyn, G.
Since 1986, the CPHR has offered a national service of calibration of dosimetric instruments at levels of radiation protection. The history of such a service is the chronology of efforts to reduce the uncertainties of the calibration process, expand the ranges of useful dose rates, and enhance the radiological safety when using the sources. The crowning of those efforts is the complement and start-up of the secondary la laboratory of dosimetric calibration (SLDC), which is currently a member of the IAEA/WHO. SLDC international network. As a result of this service, 256 instruments have been calibration and 867 personal dosimeters film badges and TLD and 72 environmental TLD dosimeters have been irradiated at known doses. The service rendered has benefited 62 national institutions which are users of ionizing radiations
Ultra-portable field transfer radiometer for vicarious calibration of earth imaging sensors
Thome, Kurtis; Wenny, Brian; Anderson, Nikolaus; McCorkel, Joel; Czapla-Myers, Jeffrey; Biggar, Stuart
A small portable transfer radiometer has been developed as part of an effort to ensure the quality of upwelling radiance from test sites used for vicarious calibration in the solar reflective. The test sites are used to predict top-of-atmosphere reflectance relying on ground-based measurements of the atmosphere and surface. The portable transfer radiometer is designed for one-person operation for on-site field calibration of instrumentation used to determine ground-leaving radiance. The current work describes the detector- and source-based radiometric calibration of the transfer radiometer highlighting the expected accuracy and SI-traceability. The results indicate differences between the detector-based and source-based results greater than the combined uncertainties of the approaches. Results from recent field deployments of the transfer radiometer using a solar radiation based calibration agree with the source-based laboratory calibration within the combined uncertainties of the methods. The detector-based results show a significant difference to the solar-based calibration. The source-based calibration is used as the basis for a radiance-based calibration of the Landsat-8 Operational Land Imager that agrees with the OLI calibration to within the uncertainties of the methods.
In-Flight Calibration of the MMS Fluxgate Magnetometers
Bromund, K. R.; Plaschke, F.; Strangeway, R. J.; Anderson, B. J.; Huang, B. G.; Magnes, W.; Fischer, D.; Nakamura, R.; Leinweber, H. K.; Russell, C. T.;
We present an overview of the approach to in-flight calibration, which is a coordinated effort between the University of California Los Angeles (UCLA), Space Research Institute, Graz, Austria (IWF) and the NASA Goddard Space Flight Center (GSFC). We present details of the calibration effort at GSFC. During the first dayside season of the Magnetospheric Multiscale (MMS) mission, the in-flight calibration process for the Fluxgate magnetometers (FGM) implemented an algorithm that selected a constant offset (zero-level) for each sensor on each orbit. This method was generally able to reduce the amplitude of residual spin tone to less than 0.2 nT within the region of interest. However, there are times when the offsets do show significant short-term variations. These variations are most prominent in the nighttime season (phase 1X), when eclipses are accompanied by offset changes as large as 1 nT. Eclipses are followed by a recovery period as long as 12 hours where the offsets continue to change as temperatures stabilize. Understanding and compensating for these changes will become critical during Phase 2 of the mission in 2017, when the nightside will become the focus of MMS science. Although there is no direct correlation between offset and temperature, the offsets are seen for the period of any given week to be well-characterized as function of instrument temperature. Using this property, a new calibration method has been developed that has proven effective in compensating for temperature-dependent offsets during phase 1X of the MMS mission and also promises to further refine calibration quality during the dayside season.
Uniformity calibration for ICT image
International Nuclear Information System (INIS)
Zeng Gang; Liu Li; Que Jiemin; Zhang Yingping; Yin Yin; Wang Yanfang; Yu Zhongqiang; Yan Yonglian
The uniformity of ICT image is impaired by beam hardening and the inconsistency of detector units responses. The beam hardening and the nonlinearity of the detector's output have been analyzed. The correction factors are determined experimentally by the detector's responses with different absorption length. The artifacts in the CT image of a symmetrical aluminium cylinder have been eliminated after calibration. (author)
Calibration of the Wedge Prism
Charles B. Briscoe
Since the introduction of plotless cruising in this country by Grosenbaugh and the later suggestion of using a wedge prism as an angle gauge by Bruce this method of determining basal area has been widely adopted in the South. One of the factors contributing to the occasionally unsatisfactory results obtained is failure to calibrate the prism used. As noted by Bruce the...
Effect of MODIS Terra Radiometric Calibration Improvements on Collection 6 Deep Blue Aerosol Products: Validation and Terra/Aqua Consistency
Sayer, A. M.; Hsu, N. C.; Bettenhausen, C.; Jeong, M.-J.; Meister, G.
The Deep Blue (DB) algorithm's primary data product is midvisible aerosol optical depth (AOD). DB applied to Moderate Resolution Imaging Spectroradiometer (MODIS) measurements provides a data record since early 2000 for MODIS Terra and mid-2002 for MODIS Aqua. In the previous data version (Collection 5, C5), DB production from Terra was halted in 2007 due to sensor degradation; the new Collection 6 (C6) has both improved science algorithms and sensor radiometric calibration. This includes additional calibration corrections developed by the Ocean Biology Processing Group to address MODIS Terra's gain, polarization sensitivity, and detector response versus scan angle, meaning DB can now be applied to the whole Terra record. Through validation with Aerosol Robotic Network (AERONET) data, it is shown that the C6 DB Terra AOD quality is stable throughout the mission to date. Compared to the C5 calibration, in recent years the RMS error compared to AERONET is smaller by approximately 0.04 over bright (e.g., desert) and approximately 0.01-0.02 over darker (e.g., vegetated) land surfaces, and the fraction of points in agreement with AERONET within expected retrieval uncertainty higher by approximately 10% and approximately 5%, respectively. Comparisons to the Aqua C6 time series reveal a high level of correspondence between the two MODIS DB data records, with a small positive (Terra-Aqua) average AOD offset <0.01. The analysis demonstrates both the efficacy of the new radiometric calibration efforts and that the C6 MODIS Terra DB AOD data remain stable (to better than 0.01 AOD) throughout the mission to date, suitable for quantitative scientific analyses.
High Gain Antenna Calibration on Three Spacecraft
Hashmall, Joseph A.
This paper describes the alignment calibration of spacecraft High Gain Antennas (HGAs) for three missions. For two of the missions (the Lunar Reconnaissance Orbiter and the Solar Dynamics Observatory) the calibration was performed on orbit. For the third mission (the Global Precipitation Measurement core satellite) ground simulation of the calibration was performed in a calibration feasibility study. These three satellites provide a range of calibration situations-Lunar orbit transmitting to a ground antenna for LRO, geosynchronous orbit transmitting to a ground antenna fer SDO, and low Earth orbit transmitting to TDRS satellites for GPM The calibration results depend strongly on the quality and quantity of calibration data. With insufficient data the calibration Junction may give erroneous solutions. Manual intervention in the calibration allowed reliable parameters to be generated for all three missions.
On the long-term stability of calibration standards in different matrices
International Nuclear Information System (INIS)
Kandić, A.; Vukanac, I.; Djurašević, M.; Novković, D.; Šešlak, B.; Milošević, Z.
In order to assure Quality Control in accordance with ISO/IEC 17025, it was important, from metrological point of view, to examine the long-term stability of calibration standards previously prepared. Comprehensive reconsideration on efficiency curves with respect to the ageing of calibration standards is presented in this paper. The calibration standards were re-used after a period of 5 years and analysis of the results showed discrepancies in efficiency values. - Highlights: ► Long-term stability of calibration standards (ISO 17025 Quality Control) was analyzed. ► Calibration standards covered the wide range of densities and chemical composition. ► Mineralized grass, powdered milk, surface soil and sand were used as standard matrices. ► Calibration standards were re-evaluated after 5 years. ► Results showed discrepancies of efficiency values.
Transient Inverse Calibration of Site-Wide Groundwater Model to Hanford Operational Impacts from 1943 to 1996-Alternative Conceptual Model Considering Interaction with Uppermost Basalt Confined Aquifer; FINAL
International Nuclear Information System (INIS)
Vermeul, Vince R; Cole, Charles R; Bergeron, Marcel P; Thorne, Paul D; Wurstner, Signe K
The baseline three-dimensional transient inverse model for the estimation of site-wide scale flow parameters, including their uncertainties, using data on the transient behavior of the unconfined aquifer system over the entire historical period of Hanford operations, has been modified to account for the effects of basalt intercommunication between the Hanford unconfined aquifer and the underlying upper basalt confined aquifer. Both the baseline and alternative conceptual models (ACM-1) considered only the groundwater flow component and corresponding observational data in the 3-Dl transient inverse calibration efforts. Subsequent efforts will examine both groundwater flow and transport. Comparisons of goodness of fit measures and parameter estimation results for the ACM-1 transient inverse calibrated model with those from previous site-wide groundwater modeling efforts illustrate that the new 3-D transient inverse model approach will strengthen the technical defensibility of the final model(s) and provide the ability to incorporate uncertainty in predictions related to both conceptual model and parameter uncertainty
QA experience at the University of Wisconsin accredited dosimetry calibration laboratory
Energy Technology Data Exchange (ETDEWEB)
DeWard, L.A.; Micka, J.A. [Univ. of Wisconsin, Madison, WI (United States)
The University of Wisconsin Accredited Dosimetry Calibration Laboratory (UW ADCL) employs procedure manuals as part of its Quality Assurance (QA) program. One of these manuals covers the QA procedures and results for all of the UW ADCL measurement equipment. The QA procedures are divided into two main areas: QA for laboratory equipment and QA for external chambers sent for calibration. All internal laboratory equipment is checked and recalibrated on an annual basis, after establishing its consistency on a 6-month basis. QA for external instruments involves checking past calibration history as well as comparing to a range of calibration values for specific instrument models. Generally, the authors find that a chamber will have a variation of less than 0.5 % from previous Co-60 calibration factors, and falls within two standard deviations of previous calibrations. If x-ray calibrations are also performed, the energy response of the chamber is plotted and compared to previous instruments of the same model. These procedures give the authors confidence in the transfer of calibration values from National Institute of Standards and Technology (NIST).
QA experience at the University of Wisconsin accredited dosimetry calibration laboratory
International Nuclear Information System (INIS)
DeWard, L.A.; Micka, J.A.
The University of Wisconsin Accredited Dosimetry Calibration Laboratory (UW ADCL) employs procedure manuals as part of its Quality Assurance (QA) program. One of these manuals covers the QA procedures and results for all of the UW ADCL measurement equipment. The QA procedures are divided into two main areas: QA for laboratory equipment and QA for external chambers sent for calibration. All internal laboratory equipment is checked and recalibrated on an annual basis, after establishing its consistency on a 6-month basis. QA for external instruments involves checking past calibration history as well as comparing to a range of calibration values for specific instrument models. Generally, the authors find that a chamber will have a variation of less than 0.5 % from previous Co-60 calibration factors, and falls within two standard deviations of previous calibrations. If x-ray calibrations are also performed, the energy response of the chamber is plotted and compared to previous instruments of the same model. These procedures give the authors confidence in the transfer of calibration values from National Institute of Standards and Technology (NIST)
A New Empirical Metallicity Calibration for Vilnius Photometry
Directory of Open Access Journals (Sweden)
Bartašiūtė S.
Full Text Available We present a new calibration of the seven-color Vilnius system in terms of [Fe/H], applicable to F–M stars in the metallicity range −2.8 ≤[Fe/H]≤ +0.5. We employ a purely empirical approach, based on ~1000 calibrating stars with high-resolution spectroscopic abundance determinations. It is shown that the color index P–Y is the best choice for a most accurate and sensitive abundance indicator for both dwarf and giant stars. Using it, [Fe/H] values can be determined with an accuracy of ±0.12 dex for stars of solar and mildly subsolar metallicity and ±0.17 dex for stars with [Fe/H] < −1. The new calibration is a significant improvement over the previous one used to date.
Effective radiation attenuation calibration for breast density: compression thickness influences and correction
Directory of Open Access Journals (Sweden)
Thomas Jerry A
Full Text Available Abstract Background Calibrating mammograms to produce a standardized breast density measurement for breast cancer risk analysis requires an accurate spatial measure of the compressed breast thickness. Thickness inaccuracies due to the nominal system readout value and compression paddle orientation induce unacceptable errors in the calibration. Method A thickness correction was developed and evaluated using a fully specified two-component surrogate breast model. A previously developed calibration approach based on effective radiation attenuation coefficient measurements was used in the analysis. Water and oil were used to construct phantoms to replicate the deformable properties of the breast. Phantoms consisting of measured proportions of water and oil were used to estimate calibration errors without correction, evaluate the thickness correction, and investigate the reproducibility of the various calibration representations under compression thickness variations. Results The average thickness uncertainty due to compression paddle warp was characterized to within 0.5 mm. The relative calibration error was reduced to 7% from 48-68% with the correction. The normalized effective radiation attenuation coefficient (planar representation was reproducible under intra-sample compression thickness variations compared with calibrated volume measures. Conclusion Incorporating this thickness correction into the rigid breast tissue equivalent calibration method should improve the calibration accuracy of mammograms for risk assessments using the reproducible planar calibration measure.
Improving quantitative precision and throughput by reducing calibrator use in liquid chromatography-tandem mass spectrometry
Energy Technology Data Exchange (ETDEWEB)
Rule, Geoffrey S., E-mail: email@example.com [ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Rockwood, Alan L. [ARUP Institute for Clinical and Experimental Pathology, 500 Chipeta Way, Salt Lake City, UT 84108 (United States); Department of Pathology, University of Utah School of Medicine, 2100 Jones Medical Research Bldg., Salt Lake City, UT 84132 (United States)
To improve efficiency in our mass spectrometry laboratories we have made efforts to reduce the number of calibration standards utilized for quantitation over time. We often analyze three or more batches of 96 samples per day, on a single instrument, for a number of assays. With a conventional calibration scheme at six concentration levels this amounts to more than 5000 calibration points per year. Modern LC-tandem mass spectrometric instrumentation is extremely rugged however, and isotopically labelled internal standards are widely available. This made us consider whether alternative calibration strategies could be utilized to reduce the number of calibration standards analyzed while still retaining high precision and accurate quantitation. Here we demonstrate how, by utilizing a single calibration point in each sample batch, and using the resulting response factor (RF) to update an existing, historical response factor (HRF), we are able to obtain improved precision over a conventional multipoint calibration approach, as judged by quality control samples. The laboratory component of this study was conducted with an existing LC tandem mass spectrometric method for three androgen analytes in our production laboratory. Using examples from both simulated and laboratory data we illustrate several aspects of our single point alternative calibration strategy and compare it with a conventional, multipoint calibration approach. We conclude that both the cost and burden of preparing multiple calibration standards with every batch of samples can be reduced while at the same time maintaining, or even improving, analytical quality. - Highlights: • Use of a weighted single point calibration approach improves quantitative precision. • A weighted response factor approach incorporates historical calibration information. • Several scenarios are discussed with regard to their influence on quantitation.
Improving quantitative precision and throughput by reducing calibrator use in liquid chromatography-tandem mass spectrometry
International Nuclear Information System (INIS)
Rule, Geoffrey S.; Rockwood, Alan L.
To improve efficiency in our mass spectrometry laboratories we have made efforts to reduce the number of calibration standards utilized for quantitation over time. We often analyze three or more batches of 96 samples per day, on a single instrument, for a number of assays. With a conventional calibration scheme at six concentration levels this amounts to more than 5000 calibration points per year. Modern LC-tandem mass spectrometric instrumentation is extremely rugged however, and isotopically labelled internal standards are widely available. This made us consider whether alternative calibration strategies could be utilized to reduce the number of calibration standards analyzed while still retaining high precision and accurate quantitation. Here we demonstrate how, by utilizing a single calibration point in each sample batch, and using the resulting response factor (RF) to update an existing, historical response factor (HRF), we are able to obtain improved precision over a conventional multipoint calibration approach, as judged by quality control samples. The laboratory component of this study was conducted with an existing LC tandem mass spectrometric method for three androgen analytes in our production laboratory. Using examples from both simulated and laboratory data we illustrate several aspects of our single point alternative calibration strategy and compare it with a conventional, multipoint calibration approach. We conclude that both the cost and burden of preparing multiple calibration standards with every batch of samples can be reduced while at the same time maintaining, or even improving, analytical quality. - Highlights: • Use of a weighted single point calibration approach improves quantitative precision. • A weighted response factor approach incorporates historical calibration information. • Several scenarios are discussed with regard to their influence on quantitation.
Calibration of working standard ionization chambers and dose standardization
International Nuclear Information System (INIS)
Abd Elmahoud, A. A. B.
Measurements were performed for the calibration of two working standard ionization chambers in the secondary standard dosimetry laboratory of Sudan. 600 cc cylindrical former type and 1800 cc cylindrical radical radiation protection level ionization chambers were calibrated against 1000 cc spherical reference standard ionization chamber. The chamber were calibrated at X-ray narrow spectrum series with beam energies ranged from (33-116 KeV) in addition to 1''3''7''Cs beam with 662 KeV energy. The chambers 0.6 cc and 0.3 cc therapy level ionization were used for dose standardization and beam output calibrations of cobalt-60 radiotherapy machine located at the National Cancer Institute, University of Gazira. Concerning beam output measurements for 6''0''Co radiotherapy machine, dosimetric measurements were performed in accordance with the relevant per IAEA dosimetry protocols TRS-277 and TRS-398. The kinetic energy released per unit mass in air (air kerma) were obtained by multiplying the corrected electrometer reading (nC/min) by the calibration factors (Gy/n C) of the chambers from given in the calibration certificate. The uncertainty of measurements of air kerma were calculated for the all ionization chambers (combined uncertainty) the calibration factors of these ionization chambers then were calculated by comparing the reading of air kerma of secondary standard ionization chambers to than from radical and farmer chambers. The result of calibration working standard ionization chambers showed different calibration factors ranged from 0.99 to 1.52 for different radiation energies and these differences were due to chambers response and specification. The absorbed dose to to water calculated for therapy ionization chamber using two code of practice TRS-277 and TRS-398 as beam output for 6''0''Co radiotherapy machine and it can be used as a reference for future beam output calibration in radiotherapy dosimetry. The measurement of absorbed dose to water showed that the
Radiometric Calibration of Osmi Imagery Using Solar Calibration
Directory of Open Access Journals (Sweden)
Dong-Han Lee
Full Text Available OSMI (Ocean Scanning Multi-Spectral Imager raw image data (Level 0 were acquired and radiometrically corrected. We have applied two methods, using solar & dark calibration data from OSMI sensor and comparing with the SeaWiFS data, to the radiometric correction of OSMI raw image data. First, we could get the values of the gain and the offset for each pixel and each band from comparing the solar & dark calibration data with the solar input radiance values, calculated from the transmittance, BRDF (Bidirectional Reflectance Distribution Function and the solar incidence angle (¥â,¥è of OSMI sensor. Applying this calibration data to OSMI raw image data, we got the two odd results, the lower value of the radiometric corrected image data than the expected value, and the Venetian Blind Effect in the radiometric corrected image data. Second, we could get the reasonable results from comparing OSMI raw image data with the SeaWiFS data, and get a new problem of OSMI sensor.
Using genetic algorithms to calibrate a water quality model.
Liu, Shuming; Butler, David; Brazier, Richard; Heathwaite, Louise; Khu, Soon-Thiam
With the increasing concern over the impact of diffuse pollution on water bodies, many diffuse pollution models have been developed in the last two decades. A common obstacle in using such models is how to determine the values of the model parameters. This is especially true when a model has a large number of parameters, which makes a full range of calibration expensive in terms of computing time. Compared with conventional optimisation approaches, soft computing techniques often have a faster convergence speed and are more efficient for global optimum searches. This paper presents an attempt to calibrate a diffuse pollution model using a genetic algorithm (GA). Designed to simulate the export of phosphorus from diffuse sources (agricultural land) and point sources (human), the Phosphorus Indicators Tool (PIT) version 1.1, on which this paper is based, consisted of 78 parameters. Previous studies have indicated the difficulty of full range model calibration due to the number of parameters involved. In this paper, a GA was employed to carry out the model calibration in which all parameters were involved. A sensitivity analysis was also performed to investigate the impact of operators in the GA on its effectiveness in optimum searching. The calibration yielded satisfactory results and required reasonable computing time. The application of the PIT model to the Windrush catchment with optimum parameter values was demonstrated. The annual P loss was predicted as 4.4 kg P/ha/yr, which showed a good fitness to the observed value.
SMAP RADAR Calibration and Validation
West, R. D.; Jaruwatanadilok, S.; Chaubel, M. J.; Spencer, M.; Chan, S. F.; Chen, C. W.; Fore, A.
The Soil Moisture Active Passive (SMAP) mission launched on Jan 31, 2015. The mission employs L-band radar and radiometer measurements to estimate soil moisture with 4% volumetric accuracy at a resolution of 10 km, and freeze-thaw state at a resolution of 1-3 km. Immediately following launch, there was a three month instrument checkout period, followed by six months of level 1 (L1) calibration and validation. In this presentation, we will discuss the calibration and validation activities and results for the L1 radar data. Early SMAP radar data were used to check commanded timing parameters, and to work out issues in the low- and high-resolution radar processors. From April 3-13 the radar collected receive only mode data to conduct a survey of RFI sources. Analysis of the RFI environment led to a preferred operating frequency. The RFI survey data were also used to validate noise subtraction and scaling operations in the radar processors. Normal radar operations resumed on April 13. All radar data were examined closely for image quality and calibration issues which led to improvements in the radar data products for the beta release at the end of July. Radar data were used to determine and correct for small biases in the reported spacecraft attitude. Geo-location was validated against coastline positions and the known positions of corner reflectors. Residual errors at the time of the beta release are about 350 m. Intra-swath biases in the high-resolution backscatter images are reduced to less than 0.3 dB for all polarizations. Radiometric cross-calibration with Aquarius was performed using areas of the Amazon rain forest. Cross-calibration was also examined using ocean data from the low-resolution processor and comparing with the Aquarius wind model function. Using all a-priori calibration constants provided good results with co-polarized measurements matching to better than 1 dB, and cross-polarized measurements matching to about 1 dB in the beta release. During the
Motivation and effort in individuals with social anhedonia.
McCarthy, Julie M; Treadway, Michael T; Blanchard, Jack J
It has been proposed that anhedonia may, in part, reflect difficulties in reward processing and effortful decision making. The current study aimed to replicate previous findings of effortful decision making deficits associated with elevated anhedonia and expand upon these findings by investigating whether these decision making deficits are specific to elevated social anhedonia or are also associated with elevated positive schizotypy characteristics. The current study compared controls (n=40) to individuals elevated on social anhedonia (n=30), and individuals elevated on perceptual aberration/magical ideation (n=30) on the Effort Expenditure for Rewards Task (EEfRT). Across groups, participants chose a higher proportion of hard tasks with increasing probability of reward and reward magnitude, demonstrating sensitivity to probability and reward values. Contrary to our expectations, when the probability of reward was most uncertain (50% probability), at low and medium reward values, the social anhedonia group demonstrated more effortful decision making than either individuals high in positive schizotypy or controls. The positive schizotypy group only differed from controls (making less effortful choices than controls) when reward probability was lowest (12%) and the magnitude of reward was the smallest. Our results suggest that social anhedonia is related to intact motivation and effort for monetary rewards, but that individuals with this characteristic display a unique and perhaps inefficient pattern of effort allocation when the probability of reward is most uncertain. Future research is needed to better understand effortful decision making and the processing of reward across a range of individual difference characteristics. Copyright © 2015 Elsevier B.V. All rights reserved.
Pocket money and child effort at school
François-Charles Wolff; Christine Barnet-Verzat
In this paper, we study the relationship between the provision of parental pocket and the level of effort undertaken by the child at school. Under altruism, an increased amount of parental transfer should reduce the child's effort. Our empirical analysis is based on a French data set including about 1,400 parent-child pairs. We find that children do not undertake less effort when their parents are more generous.
Incentive Design and Mis-Allocated Effort
Schnedler, Wendelin
Incentives often distort behavior: they induce agents to exert effort but this effort is not employed optimally. This paper proposes a theory of incentive design allowing for such distorted behavior. At the heart of the theory is a trade-off between getting the agent to exert effort and ensuring that this effort is used well. The theory covers various moral-hazard models, ranging from traditional single-task to multi-task models. It also provides -for the first time- a formalization and proof...
Automated Attitude Sensor Calibration: Progress and Plans
Sedlak, Joseph; Hashmall, Joseph
This paper describes ongoing work a NASA/Goddard Space Flight Center to improve the quality of spacecraft attitude sensor calibration and reduce costs by automating parts of the calibration process. The new calibration software can autonomously preview data quality over a given time span, select a subset of the data for processing, perform the requested calibration, and output a report. This level of automation is currently being implemented for two specific applications: inertial reference unit (IRU) calibration and sensor alignment calibration. The IRU calibration utility makes use of a sequential version of the Davenport algorithm. This utility has been successfully tested with simulated and actual flight data. The alignment calibration is still in the early testing stage. Both utilities will be incorporated into the institutional attitude ground support system.
Automated Calibration of Dosimeters for Diagnostic Radiology
International Nuclear Information System (INIS)
Romero Acosta, A.; Gutierrez Lores, S.
Calibration of dosimeters for diagnostic radiology includes current and charge measurements, which are often repetitive. However, these measurements are usually done using modern electrometers, which are equipped with an RS-232 interface that enables instrument control from a computer. This paper presents an automated system aimed to the measurements for the calibration of dosimeters used in diagnostic radiology. A software application was developed, in order to achieve the acquisition of the electric charge readings, measured values of the monitor chamber, calculation of the calibration coefficient and issue of a calibration certificate. A primary data record file is filled and stored in the computer hard disk. The calibration method used was calibration by substitution. With this system, a better control over the calibration process is achieved and the need for human intervention is reduced. the automated system will be used in the calibration of dosimeters for diagnostic radiology at the Cuban Secondary Standard Dosimetry Laboratory of the Center for Radiation Protection and Hygiene. (Author)
Crop physiology calibration in the CLM
Directory of Open Access Journals (Sweden)
I. Bilionis
scalable and adaptive scheme based on sequential Monte Carlo (SMC. The model showed significant improvement of crop productivity with the new calibrated parameters. We demonstrate that the calibrated parameters are applicable across alternative years and different sites.
Calibration of alpha surface contamination monitor
International Nuclear Information System (INIS)
Freitas, I.S.M. de; Goncalez, O.L.
In this work, the results, as well as the methodology, of the calibration of an alpha surface contamination monitor are presented. The calibration factors are obtained by least-squares fitting with effective variance. (author)
Calibration curves for biological dosimetry
International Nuclear Information System (INIS)
Guerrero C, C.; Brena V, M. . E-mail email@example.com
The generated information by the investigations in different laboratories of the world, included the ININ, in which settles down that certain class of chromosomal leisure it increases in function of the dose and radiation type, has given by result the obtaining of calibrated curves that are applied in the well-known technique as biological dosimetry. In this work is presented a summary of the work made in the laboratory that includes the calibrated curves for gamma radiation of 60 Cobalt and X rays of 250 k Vp, examples of presumed exposure to ionizing radiation, resolved by means of aberration analysis and the corresponding dose estimate through the equations of the respective curves and finally a comparison among the dose calculations in those people affected by the accident of Ciudad Juarez, carried out by the group of Oak Ridge, USA and those obtained in this laboratory. (Author)
Astrid-2 EMMA Magnetic Calibration
DEFF Research Database (Denmark)
Merayo, José M.G.; Brauer, Peter; Risbo, Torben
The Swedish micro-satellite Astrid-2 contains a tri-axial fluxgate magnetometer with the sensor co-located with a Technical University of Denmark (DTU) star camera for absolute attitude, and extended about 0.9 m on a hinged boom. The magnetometer is part of the RIT EMMA electric and magnetic fields...... experiment built as a collaboration between the DTU, Department of Automation and the Department of Plasma Physics, The Alfvenlaboratory, Royal Institute of Technology (RIT), Stockholm. The final magnetic calibration of the Astrid-2 satellite was done at the Lovoe Magnetic Observatory under the Geological...... Survey of Sweden near Stockholm on the night of May 15.-16., 1997. The magnetic calibration and the intercalibration between the star camera and the magnetic sensor was performed by measuring the Earth's magnetic field and simultaneously observing the star sky with the camera. The rotation matrix between...
Quality control for dose calibrators
International Nuclear Information System (INIS)
Mendes, L.C.G.
Nuclear medicine laboratories are required to assay samples of radioactivity to be administered to patients. Almost universally, these assays are accomplished by use of a well ionization chamber isotope calibrator. The Instituto de Radioprotecao e Dosimetria (Institute for Radiological Protection and Dosimetry) of the Comissao Nacional de Energia Nuclear (National Commission for Nuclear Energy) is carrying out a National Quality Control Programme in Nuclear Medicine, supported by the International Atomic Energy Agency. The assessment of the current needs and practices of quality control in the entire country of Brazil includes Dose Calibrators and Scintillation Cameras, but this manual is restricted to the former. Quality Control Procedures for these Instruments are described in this document together with specific recommendations and assessment of its accuracy. (author)
Satellite imager calibration and validation
CSIR Research Space (South Africa)
Vhengani, L
Full Text Available and Validation Lufuno Vhengani*, Minette Lubbe, Derek Griffith and Meena Lysko Council for Scientific and Industrial Research, Defence Peace Safety and Security, Pretoria, South Africa E-mail: * email@example.com Abstract: The success or failure... techniques specific to South Africa. 1. Introduction The success or failure of any earth observation mission depends on the quality of its data. To achieve optimum levels of reliability most sensors are calibrated pre-launch. However...
Multidetector calibration for mass spectrometers
International Nuclear Information System (INIS)
Bayne, C.K.; Donohue, D.L.; Fiedler, R.
The International Atomic Energy Agency's Safeguards Analytical Laboratory has performed calibration experiments to measure the different efficiencies among multi-Faraday detectors for a Finnigan-MAT 261 mass spectrometer. Two types of calibration experiments were performed: (1) peak-shift experiments and (2) peak-jump experiments. For peak-shift experiments, the ion intensities were measured for all isotopes of an element in different Faraday detectors. Repeated measurements were made by shifting the isotopes to various Faraday detectors. Two different peak-shifting schemes were used to measure plutonium (UK Pu5/92138) samples. For peak-jump experiments, ion intensities were measured in a reference Faraday detector for a single isotope and compared with those measured in the other Faraday detectors. Repeated measurements were made by switching back-and-forth between the reference Faraday detector and a selected Faraday detector. This switching procedure is repeated for all Faraday detectors. Peak-jump experiments were performed with replicate measurements of 239 Pu, 187 Re, and 238 U. Detector efficiency factors were estimated for both peak-jump and peak-shift experiments using a flexible calibration model to statistically analyze both types of multidetector calibration experiments. Calculated detector efficiency factors were shown to depend on both the material analyzed and the experimental conditions. A single detector efficiency factor is not recommended for each detector that would be used to correct routine sample analyses. An alternative three-run peak-shift sample analysis should be considered. A statistical analysis of the data from this peak-shift experiment can adjust the isotopic ratio estimates for detector differences due to each sample analysis
Calibrating thermal behavior of electronics
Chainer, Timothy J.; Parida, Pritish R.; Schultz, Mark D.
A method includes determining a relationship between indirect thermal data for a processor and a measured temperature associated with the processor, during a calibration process, obtaining the indirect thermal data for the processor during actual operation of the processor, and determining an actual significant temperature associated with the processor during the actual operation using the indirect thermal data for the processor during actual operation of the processor and the relationship.
Calibration of optically trapped nanotools
Energy Technology Data Exchange (ETDEWEB)
Carberry, D M; Simpson, S H; Grieve, J A; Hanna, S; Miles, M J [H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Wang, Y; Schaefer, H; Steinhart, M [Institute for Chemistry, University of Osnabrueck, Osnabrueck (Germany); Bowman, R; Gibson, G M; Padgett, M J, E-mail: email@example.com [SUPA, Department of Physics and Astronomy, University of Glasgow, Science Road, Glasgow G12 8QQ (United Kingdom)
Holographically trapped nanotools can be used in a novel form of force microscopy. By measuring the displacement of the tool in the optical traps, the contact force experienced by the probe can be inferred. In the following paper we experimentally demonstrate the calibration of such a device and show that its behaviour is independent of small changes in the relative position of the optical traps. Furthermore, we explore more general aspects of the thermal motion of the tool.
Optimal Reliability-Based Code Calibration
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Kroon, I. B.; Faber, Michael Havbro
Calibration of partial safety factors is considered in general, including classes of structures where no code exists beforehand. The partial safety factors are determined such that the difference between the reliability for the different structures in the class considered and a target reliability...... level is minimized. Code calibration on a decision theoretical basis is also considered and it is shown how target reliability indices can be calibrated. Results from code calibration for rubble mound breakwater designs are shown....
Calibration of ALIBAVA readout system
Energy Technology Data Exchange (ETDEWEB)
Trofymov, Artur [DESY, Hamburg (Germany); Collaboration: ATLAS experiment-Collaboration
The High Luminosity Large Hadron Collider (LH-LHC) is the upgrade of the LHC that foreseen to increase the instantaneous luminosity by a factor ten with a total integrated luminosity of 3000 fb{sup -1}. The ATLAS experiment will need to build a new tracker to operate in the new severe LH-LHC conditions (increasing detector granularity to cope with much higher channel occupancy, designing radiation-hard sensors and electronics to cope with radiation damage). Charge collection efficiency (CCE) of silicon strip sensors for the new ATLAS tracker can be done with ALIBAVA analog readout system (analog system gives more information about signal from all strips than digital). In this work the preliminary results of ALIBAVA calibration using two different methods (with ''source data'' and ''calibration data'') are presented. Calibration constant obtained by these methods is necessary for knowing collected charge on the silicon strip sensors and for having the ability to compare it with measurements done at the test beam.
Calibration of RB reactor power
International Nuclear Information System (INIS)
Sotic, O.; Markovic, H.; Ninkovic, M.; Strugar, P.; Dimitrijevic, Z.; Takac, S.; Stefanovic, D.; Kocic, A.; Vranic, S.
The first and only calibration of RB reactor power was done in 1962, and the obtained calibration ratio was used irrespective of the lattice pitch and core configuration. Since the RB reactor is being prepared for operation at higher power levels it was indispensable to reexamine the calibration ratio, estimate its dependence on the lattice pitch, critical level of heavy water and thickness of the side reflector. It was necessary to verify the reliability of control and dosimetry instruments, and establish neutron and gamma dose dependence on reactor power. Two series of experiments were done in June 1976. First series was devoted to tests of control and dosimetry instrumentation and measurements of radiation in the RB reactor building dependent on reactor power. Second series covered measurement of thermal and epithermal neuron fluxes in the reactor core and calculation of reactor power. Four different reactor cores were chosen for these experiments. Reactor pitches were 8, 8√2, and 16 cm with 40, 52 and 82 fuel channels containing 2% enriched fuel. Obtained results and analysis of these results are presented in this document with conclusions related to reactor safe operation
Model Calibration in Watershed Hydrology
Yilmaz, Koray K.; Vrugt, Jasper A.; Gupta, Hoshin V.; Sorooshian, Soroosh
Hydrologic models use relatively simple mathematical equations to conceptualize and aggregate the complex, spatially distributed, and highly interrelated water, energy, and vegetation processes in a watershed. A consequence of process aggregation is that the model parameters often do not represent directly measurable entities and must, therefore, be estimated using measurements of the system inputs and outputs. During this process, known as model calibration, the parameters are adjusted so that the behavior of the model approximates, as closely and consistently as possible, the observed response of the hydrologic system over some historical period of time. This Chapter reviews the current state-of-the-art of model calibration in watershed hydrology with special emphasis on our own contributions in the last few decades. We discuss the historical background that has led to current perspectives, and review different approaches for manual and automatic single- and multi-objective parameter estimation. In particular, we highlight the recent developments in the calibration of distributed hydrologic models using parameter dimensionality reduction sampling, parameter regularization and parallel computing.
Optimal, Reliability-Based Code Calibration
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard
Reliability based code calibration is considered in this paper. It is described how the results of FORM based reliability analysis may be related to the partial safety factors and characteristic values. The code calibration problem is presented in a decision theoretical form and it is discussed how...... of reliability based code calibration of LRFD based design codes....
Code Calibration as a Decision Problem
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Kroon, I. B.; Faber, Michael Havbro
Calibration of partial coefficients for a class of structures where no code exists is considered. The partial coefficients are determined such that the difference between the reliability for the different structures in the class considered and a target reliability level is minimized. Code...... calibration on a decision theoretical basis is discussed. Results from code calibration for rubble mound breakwater designs are shown....
40 CFR 1065.310 - Torque calibration.
... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Torque calibration. 1065.310 Section... Conditions § 1065.310 Torque calibration. (a) Scope and frequency. Calibrate all torque-measurement systems including dynamometer torque measurement transducers and systems upon initial installation and after major...
Some problems in calibrating surface contamination meters
International Nuclear Information System (INIS)
Chen Zigen; LI Xingyuan; Shuai Xiaoping.
It is necessary that instruments are calibrated accurately in order to obtain reliable survey data of surface contamination. Some problems in calibrating surface contamination meters are expounded in this paper. Measurement comparison for beta surface contamination meters is organized within limited scope, thus survey quality is understood, questions are discovered, significance of calibration is expounded further. (Author)
Calibration and simulation of Heston model
Directory of Open Access Journals (Sweden)
Mrázek Milan
Full Text Available We calibrate Heston stochastic volatility model to real market data using several optimization techniques. We compare both global and local optimizers for different weights showing remarkable differences even for data (DAX options from two consecutive days. We provide a novel calibration procedure that incorporates the usage of approximation formula and outperforms significantly other existing calibration methods.
Nuclear radiation moisture gauge calibration standard
International Nuclear Information System (INIS)
A hydrophobic standard for calibrating nuclear radiation moisture gauges is described. Each standard has physical characteristics and dimensions effective for representing to a nuclear gauge undergoing calibration, an infinite mass of homogeneous hydrogen content. Calibration standards are discussed which are suitable for use with surface gauges and with depth gauges. (C.F.)
A new method for automated dynamic calibration of tipping-bucket rain gauges
Humphrey, M.D.; Istok, J.D.; Lee, J.Y.; Hevesi, J.A.; Flint, A.L.
Existing methods for dynamic calibration of tipping-bucket rain gauges (TBRs) can be time consuming and labor intensive. A new automated dynamic calibration system has been developed to calibrate TBRs with minimal effort. The system consists of a programmable pump, datalogger, digital balance, and computer. Calibration is performed in two steps: 1) pump calibration and 2) rain gauge calibration. Pump calibration ensures precise control of water flow rates delivered to the rain gauge funnel; rain gauge calibration ensures precise conversion of bucket tip times to actual rainfall rates. Calibration of the pump and one rain gauge for 10 selected pump rates typically requires about 8 h. Data files generated during rain gauge calibration are used to compute rainfall intensities and amounts from a record of bucket tip times collected in the field. The system was tested using 5 types of commercial TBRs (15.2-, 20.3-, and 30.5-cm diameters; 0.1-, 0.2-, and 1.0-mm resolutions) and using 14 TBRs of a single type (20.3-cm diameter; 0.1-mm resolution). Ten pump rates ranging from 3 to 154 mL min-1 were used to calibrate the TBRs and represented rainfall rates between 6 and 254 mm h-1 depending on the rain gauge diameter. All pump calibration results were very linear with R2 values greater than 0.99. All rain gauges exhibited large nonlinear underestimation errors (between 5% and 29%) that decreased with increasing rain gauge resolution and increased with increasing rainfall rate, especially for rates greater than 50 mm h-1. Calibration curves of bucket tip time against the reciprocal of the true pump rate for all rain gauges also were linear with R2 values of 0.99. Calibration data for the 14 rain gauges of the same type were very similar, as indicated by slope values that were within 14% of each other and ranged from about 367 to 417 s mm h-1. The developed system can calibrate TBRs efficiently, accurately, and virtually unattended and could be modified for use with other
Time preferences, study effort, and academic performance
Non, J.A.; Tempelaar, D.T.
We analyze the relation between time preferences, study effort, and academic performance among first-year Business and Economics students. Time preferences are measured by stated preferences for an immediate payment over larger delayed payments. Data on study efforts are derived from an electronic
Interests, Effort, Achievement and Vocational Preference.
Sjoberg, L.
Relationships between interest in natural sciences and technology and perceived ability, success, and invested effort were studied in Swedish secondary school students. Interests were accounted for by logical orientation and practical value. Interests and grades were strongly correlated, but correlations between interests and effort and vocational…
Dopamine and Effort-Based Decision Making
Directory of Open Access Journals (Sweden)
Irma Triasih Kurniawan
Full Text Available Motivational theories of choice focus on the influence of goal values and strength of reinforcement to explain behavior. By contrast relatively little is known concerning how the cost of an action, such as effort expended, contributes to a decision to act. Effort-based decision making addresses how we make an action choice based on an integration of action and goal values. Here we review behavioral and neurobiological data regarding the representation of effort as action cost, and how this impacts on decision making. Although organisms expend effort to obtain a desired reward there is a striking sensitivity to the amount of effort required, such that the net preference for an action decreases as effort cost increases. We discuss the contribution of the neurotransmitter dopamine (DA towards overcoming response costs and in enhancing an animal's motivation towards effortful actions. We also consider the contribution of brain structures, including the basal ganglia (BG and anterior cingulate cortex (ACC, in the internal generation of action involving a translation of reward expectation into effortful action.
Listening Effort With Cochlear Implant Simulations
Pals, Carina; Sarampalis, Anastasios; Başkent, Deniz
Purpose: Fitting a cochlear implant (CI) for optimal speech perception does not necessarily optimize listening effort. This study aimed to show that listening effort may change between CI processing conditions for which speech intelligibility remains constant. Method: Nineteen normal-hearing
Effort and Selection Effects of Incentive Contracts
Bouwens, J.F.M.G.; van Lent, L.A.G.M.
We show that the improved effort of employees associated with incentive contracts depends on the properties of the performance measures used in the contract.We also find that the power of incentives in the contract is only indirectly related to any improved employee effort.High powered incentive
The Effect of Age on Listening Effort
Degeest, Sofie; Keppler, Hannah; Corthals, Paul
Purpose: The objective of this study was to investigate the effect of age on listening effort. Method: A dual-task paradigm was used to evaluate listening effort in different conditions of background noise. Sixty adults ranging in age from 20 to 77 years were included. A primary speech-recognition task and a secondary memory task were performed…
Low-effort thought promotes political conservatism.
Eidelman, Scott; Crandall, Christian S; Goodman, Jeffrey A; Blanchar, John C
The authors test the hypothesis that low-effort thought promotes political conservatism. In Study 1, alcohol intoxication was measured among bar patrons; as blood alcohol level increased, so did political conservatism (controlling for sex, education, and political identification). In Study 2, participants under cognitive load reported more conservative attitudes than their no-load counterparts. In Study 3, time pressure increased participants' endorsement of conservative terms. In Study 4, participants considering political terms in a cursory manner endorsed conservative terms more than those asked to cogitate; an indicator of effortful thought (recognition memory) partially mediated the relationship between processing effort and conservatism. Together these data suggest that political conservatism may be a process consequence of low-effort thought; when effortful, deliberate thought is disengaged, endorsement of conservative ideology increases.
Acoustic calibration apparatus for calibrating plethysmographic acoustic pressure sensors
Zuckerwar, Allan J. (Inventor); Davis, David C. (Inventor)
An apparatus for calibrating an acoustic sensor is described. The apparatus includes a transmission material having an acoustic impedance approximately matching the acoustic impedance of the actual acoustic medium existing when the acoustic sensor is applied in actual in-service conditions. An elastic container holds the transmission material. A first sensor is coupled to the container at a first location on the container and a second sensor coupled to the container at a second location on the container, the second location being different from the first location. A sound producing device is coupled to the container and transmits acoustic signals inside the container.
Calibration of nuclear medicine gamma counters
International Nuclear Information System (INIS)
Orlic, M.; Spasic-Jokic, V.; Jovanovic, M.; Vranjes, S. . E-mail address of corresponding author: email@example.com; Orlic, M.)
In this paper the practical problem of nuclear medicine gamma counters calibration has been solved by using dose calibrators CRC-15R with standard error ±5%. The samples from technetium generators have been measured both by dose calibrators CRC-15R and gamma counter ICN Gamma 3.33 taking into account decay correction. Only the linear part of the curve has practical meaning. The advantage of this procedure satisfies the requirements from international standards: the calibration of sources used for medical exposure be traceable to a standard dosimetry laboratory and radiopharmaceuticals for nuclear medicine procedures be calibrated in terms of activity of the radiopharmaceutical to be administered. (author)
Cross-calibration of interferometric SAR data
DEFF Research Database (Denmark)
Dall, Jørgen
Generation of digital elevation models from interferometric synthetic aperture radar (SAR) data is a well established technique. Achieving a high geometric fidelity calls for a calibration accounting for inaccurate navigation data and system parameters as well as system imperfections. Fully...... automated calibration techniques are preferable, especially for operational mapping. The author presents one such technique, called cross-calibration. Though developed for single-pass interferometry, it may be applicable to multi-pass interferometry, too. Cross-calibration requires stability during mapping...... ground control point is often needed. The paper presents the principles and mathematics of the cross-calibration technique and illustrates its successful application to EMISAR data....
Multiple-Objective Stepwise Calibration Using Luca
Hay, Lauren E.; Umemoto, Makiko
This report documents Luca (Let us calibrate), a multiple-objective, stepwise, automated procedure for hydrologic model calibration and the associated graphical user interface (GUI). Luca is a wizard-style user-friendly GUI that provides an easy systematic way of building and executing a calibration procedure. The calibration procedure uses the Shuffled Complex Evolution global search algorithm to calibrate any model compiled with the U.S. Geological Survey's Modular Modeling System. This process assures that intermediate and final states of the model are simulated consistently with measured values.
Low-Cost Photometric Calibration for Interactive Relighting
Loscos , Céline; Drettakis , George
International audience; Computer augmented reality is a rapidly emerging field allowing users to mix virtual and real worlds. Our interest is to allow relighting and remodelling of real scenes, using a reflectance estimation method. Most previous work focused on the quality of the results without considering the expense in computation and the price of acquisition equipment. In this paper, we present a low–cost photometric calibration method which improves the reflectance estimate of real scen...
Experimental and calculated calibration of ionization chambers with air circulation
Peetermans, A
The reports describes the method followed in order to calibrate the different ionization chambers with air circulation, used by the 'Health Physics Group'. The calculations agree more precisely with isotopes cited previously (/sup 11/C, /sup 13/N, /sup 15/O, /sup 41 /Ar, /sup 14/O, /sup 38/Cl) as well as for /sup 85/Kr, /sup 133/Xe, /sup 14/C and tritium which are used for the experimental standardisation of different chambers.
Towards a global network of gamma-ray detector calibration facilities
Tijs, Marco; Koomans, Ronald; Limburg, Han
Gamma-ray logging tools are applied worldwide. At various locations, calibration facilities are used to calibrate these gamma-ray logging systems. Several attempts have been made to cross-correlate well known calibration pits, but this cross-correlation does not include calibration facilities in Europe or private company calibration facilities. Our aim is to set-up a framework that gives the possibility to interlink all calibration facilities worldwide by using `tools of opportunity' - tools that have been calibrated in different calibration facilities, whether this usage was on a coordinated basis or by coincidence. To compare the measurement of different tools, it is important to understand the behaviour of the tools in the different calibration pits. Borehole properties, such as diameter, fluid, casing and probe diameter strongly influence the outcome of gamma-ray borehole logging. Logs need to be properly calibrated and compensated for these borehole properties in order to obtain in-situ grades or to do cross-hole correlation. Some tool providers provide tool-specific correction curves for this purpose. Others rely on reference measurements against sources of known radionuclide concentration and geometry. In this article, we present an attempt to set-up a framework for transferring `local' calibrations to be applied `globally'. This framework includes corrections for any geometry and detector size to give absolute concentrations of radionuclides from borehole measurements. This model is used to compare measurements in the calibration pits of Grand Junction, located in the USA; Adelaide (previously known as AMDEL), located in Adelaide Australia; and Stonehenge, located at Medusa Explorations BV in the Netherlands.
Calibration methods for the Hargreaves-Samani equation
Directory of Open Access Journals (Sweden)
Lucas Borges Ferreira
Full Text Available ABSTRACT The estimation of the reference evapotranspiration is an important factor for hydrological studies, design and management of irrigation systems, among others. The Penman Monteith equation presents high precision and accuracy in the estimation of this variable. However, its use becomes limited due to the large number of required meteorological data. In this context, the Hargreaves-Samani equation could be used as alternative, although, for a better performance a local calibration is required. Thus, the aim was to compare the calibration process of the Hargreaves-Samani equation by linear regression, by adjustment of the coefficients (A and B and exponent (C of the equation and by combinations of the two previous alternatives. Daily data from 6 weather stations, located in the state of Minas Gerais, from the period 1997 to 2016 were used. The calibration of the Hargreaves-Samani equation was performed in five ways: calibration by linear regression, adjustment of parameter "A", adjustment of parameters "A" and "C", adjustment of parameters "A", "B" and "C" and adjustment of parameters "A", "B" and "C" followed by calibration by linear regression. The performances of the models were evaluated based on the statistical indicators mean absolute error, mean bias error, Willmott's index of agreement, correlation coefficient and performance index. All the studied methodologies promoted better estimations of reference evapotranspiration. The simultaneous adjustment of the empirical parameters "A", "B" and "C" was the best alternative for calibration of the Hargreaves-Samani equation.
Calibration of the clumped isotope thermometer for planktic foraminifers
Meinicke, N.; Ho, S. L.; Nürnberg, D.; Tripati, A. K.; Jansen, E.; Dokken, T.; Schiebel, R.; Meckler, A. N.
Many proxies for past ocean temperature suffer from secondary influences or require species-specific calibrations that might not be applicable on longer time scales. Being thermodynamically based and thus independent of seawater composition, clumped isotopes in carbonates (Δ47) have the potential to circumvent such issues affecting other proxies and provide reliable temperature reconstructions far back in time and in unknown settings. Although foraminifers are commonly used for paleoclimate reconstructions, their use for clumped isotope thermometry has been hindered so far by large sample-size requirements. Existing calibration studies suggest that data from a variety of foraminifer species agree with synthetic carbonate calibrations (Tripati, et al., GCA, 2010; Grauel, et al., GCA, 2013). However, these studies did not include a sufficient number of samples to fully assess the existence of species-specific effects, and data coverage was especially sparse in the low temperature range (analysis of smaller sample sizes (3-5 mg), hence also the measurement of multiple species from the same samples. We analyzed surface-dwelling ( 0-50 m) species and deep-dwelling (habitat depth up to several hundred meters) planktic foraminifers from the same sites to evaluate species-specific effects and to assess the feasibility of temperature reconstructions for different water depths. We also assess the effects of different techniques in estimating foraminifer calcification temperature on the calibration. Finally, we compare our calibration to existing clumped isotope calibrations. Our results confirm previous findings that indicate no species-specific effects on the Δ47-temperature relationship measured in planktic foraminifers.
Solid laboratory calibration of a nonimaging spectroradiometer.
Schaepman, M E; Dangel, S
Field-based nonimaging spectroradiometers are often used in vicarious calibration experiments for airborne or spaceborne imaging spectrometers. The calibration uncertainties associated with these ground measurements contribute substantially to the overall modeling error in radiance- or reflectance-based vicarious calibration experiments. Because of limitations in the radiometric stability of compact field spectroradiometers, vicarious calibration experiments are based primarily on reflectance measurements rather than on radiance measurements. To characterize the overall uncertainty of radiance-based approaches and assess the sources of uncertainty, we carried out a full laboratory calibration. This laboratory calibration of a nonimaging spectroradiometer is based on a measurement plan targeted at achieving a =10% uncertainty calibration. The individual calibration steps include characterization of the signal-to-noise ratio, the noise equivalent signal, the dark current, the wavelength calibration, the spectral sampling interval, the nonlinearity, directional and positional effects, the spectral scattering, the field of view, the polarization, the size-of-source effects, and the temperature dependence of a particular instrument. The traceability of the radiance calibration is established to a secondary National Institute of Standards and Technology calibration standard by use of a 95% confidence interval and results in an uncertainty of less than ?7.1% for all spectroradiometer bands.
Muon Energy Calibration of the MINOS Detectors
Energy Technology Data Exchange (ETDEWEB)
Miyagawa, Paul S. [Somerville College, Oxford (United Kingdom)
MINOS is a long-baseline neutrino oscillation experiment designed to search for conclusive evidence of neutrino oscillations and to measure the oscillation parameters precisely. MINOS comprises two iron tracking calorimeters located at Fermilab and Soudan. The Calibration Detector at CERN is a third MINOS detector used as part of the detector response calibration programme. A correct energy calibration between these detectors is crucial for the accurate measurement of oscillation parameters. This thesis presents a calibration developed to produce a uniform response within a detector using cosmic muons. Reconstruction of tracks in cosmic ray data is discussed. This data is utilized to calculate calibration constants for each readout channel of the Calibration Detector. These constants have an average statistical error of 1.8%. The consistency of the constants is demonstrated both within a single run and between runs separated by a few days. Results are presented from applying the calibration to test beam particles measured by the Calibration Detector. The responses are calibrated to within 1.8% systematic error. The potential impact of the calibration on the measurement of oscillation parameters by MINOS is also investigated. Applying the calibration reduces the errors in the measured parameters by ~ 10%, which is equivalent to increasing the amount of data by 20%.
Visual cues and listening effort: individual variability.
Picou, Erin M; Ricketts, Todd A; Hornsby, Benjamin W Y
To investigate the effect of visual cues on listening effort as well as whether predictive variables such as working memory capacity (WMC) and lipreading ability affect the magnitude of listening effort. Twenty participants with normal hearing were tested using a paired-associates recall task in 2 conditions (quiet and noise) and 2 presentation modalities (audio only [AO] and auditory-visual [AV]). Signal-to-noise ratios were adjusted to provide matched speech recognition across audio-only and AV noise conditions. Also measured were subjective perceptions of listening effort and 2 predictive variables: (a) lipreading ability and (b) WMC. Objective and subjective results indicated that listening effort increased in the presence of noise, but on average the addition of visual cues did not significantly affect the magnitude of listening effort. Although there was substantial individual variability, on average participants who were better lipreaders or had larger WMCs demonstrated reduced listening effort in noise in AV conditions. Overall, the results support the hypothesis that integrating auditory and visual cues requires cognitive resources in some participants. The data indicate that low lipreading ability or low WMC is associated with relatively effortful integration of auditory and visual information in noise.
IAEA Patient Protection Effort Reaches Key Milestone
International Nuclear Information System (INIS)
Full text: An International Atomic Energy Agency (IAEA) effort to help people track their radiation exposure from medical procedures achieved a significant milestone this week. The Agency received the final approval from a group of medical oversight organizations for the 'Joint Position Statement on the IAEA Patient Radiation Exposure Tracking', a set of principles to guide patient protection efforts at the sub-national, national, and international level. The joint statement endorses the IAEA's three-year-old Smart Card/SmartRadTrack project, which aims to help nations develop systems to track medical radiation procedures and radiation doses. The statement has been agreed by the World Health Organization (WHO), the U.S. Food and Drug Administration (FDA), the European Society of Radiology (ESR), the International Organization for Medical Physics (IOMP), the International Society of Radiographers and Radiological Technologists (ISRRT), and the Conference of Radiation Control Program Directors, USA (CRCPD). 'This system is critical if the medical community is going to keep patients safe when they are being referred for more and more diagnostic scans. These scans, over the years, are made using more and more powerful machines', said Madan Rehani, Radiation Safety Specialist in the IAEA's Radiation Protection of Patients Unit. 'The tracking system will draw doctors' attention to previous radiological examinations, both in terms of clinical information and radiation dose and thus help them assess whether the 11th or 20th CT scan is really appropriate, whether it will do more good than harm.' Advances in radiation-based diagnostic technologies, such as the CT scan, have led to patients receiving such procedures more frequently. The convenience of CT with the added advantage of increased information has resulted in increased usage to the point that there are instances of patients getting tens of CT scans in a few years, not all of which may be justified, or getting CT
"Calibration-on-the-spot": How to calibrate an EMCCD camera from its images
DEFF Research Database (Denmark)
Mortensen, Kim; Flyvbjerg, Henrik
In order to count photons with a camera, the camera must be calibrated. Photon counting is necessary, e.g., to determine the precision of localization-based super-resolution microscopy. Here we present a protocol that calibrates an EMCCD camera from information contained in isolated, diffraction-......-limited spots in any image taken by the camera, thus making dedicated calibration procedures redundant by enabling calibration post festum, from images filed without calibration information....
The Absolute Reflectance and New Calibration Site of the Moon
Wu, Yunzhao; Wang, Zhenchao; Cai, Wei; Lu, Yu
How bright the Moon is forms a simple but fundamental and important question. Although numerous efforts have been made to answer this question such as use of sophisticated electro-optical measurements and suggestions for calibration sites, the answer is still debated. An in situ measurement with a calibration panel on the surface of the Moon is crucial for obtaining the accurate absolute reflectance and resolving the debate. China's Chang'E-3 (CE-3) "Yutu" rover accomplished this type of measurement using the Visible-Near Infrared Spectrometer (VNIS). The measurements of the VNIS, which were at large emission and phase angles, complement existing measurements for the range of photometric geometry. The in situ reflectance shows that the CE-3 landing site is very dark with an average reflectance of 3.86% in the visible bands. The results are compared with recent mission instruments: the Lunar Reconnaissance Orbiter Camera (LROC) Wide Angle Camera (WAC), the Spectral Profiler (SP) on board the SELENE, the Moon Mineralogy Mapper (M3) on board the Chandrayaan-1, and the Chang'E-1 Interference Imaging Spectrometer (IIM). The differences in the measurements of these instruments are very large and indicate inherent differences in their absolute calibration. The M3 and IIM measurements are smaller than LROC WAC and SP, and the VNIS measurement falls between these two pairs. When using the Moon as a radiance source for the on-orbit calibration of spacecraft instruments, one should be cautious about the data. We propose that the CE-3 landing site, a young and homogeneous surface, should serve as the new calibration site.
Calibration Uncertainties in the Droplet Measurement Technologies Cloud Condensation Nuclei Counter
Hibert, Kurt James
average surface pressure at Grand Forks, ND. The supersaturation calibration uncertainty is 2.3, 3.1, and 4.4 % for calibrations done at 700, 840, and 980 hPa respectively. The supersaturation calibration change with pressure is on average 0.047 % supersaturation per 100 hPa. The supersaturation calibrations done at UND are 42-45 % lower than supersaturation calibrations done at DMT approximately 1 year previously. Performance checks confirmed that all major leaks developed during shipping were fixed before conducting the supersaturation calibrations. Multiply-charged particles passing through the Electrostatic Classifier may have influenced DMT's activation curves, which is likely part of the supersaturation calibration difference. Furthermore, the fitting method used to calculate the activation size and the limited calibration points are likely significant sources of error in DMT's supersaturation calibration. While the DMT CCN counter's calibration uncertainties are relatively small, and the pressure dependence is easily accounted for, the calibration methodology used by different groups can be very important. The insights gained from the careful calibration of the DMT CCN counter indicate that calibration of scientific instruments using complex methodology is not trivial.
Seepage Calibration Model and Seepage Testing Data
International Nuclear Information System (INIS)
Dixon, P.
The purpose of this Model Report is to document the Seepage Calibration Model (SCM). The SCM is developed (1) to establish the conceptual basis for the Seepage Model for Performance Assessment (SMPA), and (2) to derive seepage-relevant, model-related parameters and their distributions for use in the SMPA and seepage abstraction in support of the Total System Performance Assessment for License Application (TSPA-LA). The SCM is intended to be used only within this Model Report for the estimation of seepage-relevant parameters through calibration of the model against seepage-rate data from liquid-release tests performed in several niches along the Exploratory Studies Facility (ESF) Main Drift and in the Cross Drift. The SCM does not predict seepage into waste emplacement drifts under thermal or ambient conditions. Seepage predictions for waste emplacement drifts under ambient conditions will be performed with the SMPA (see upcoming REV 02 of CRWMS M and O 2000 [153314]), which inherits the conceptual basis and model-related parameters from the SCM. Seepage during the thermal period is examined separately in the Thermal Hydrologic (TH) Seepage Model (see BSC 2003 [161530]). The scope of this work is (1) to evaluate seepage rates measured during liquid-release experiments performed in several niches in the Exploratory Studies Facility (ESF) and in the Cross Drift, which was excavated for enhanced characterization of the repository block (ECRB); (2) to evaluate air-permeability data measured in boreholes above the niches and the Cross Drift to obtain the permeability structure for the seepage model; (3) to use inverse modeling to calibrate the SCM and to estimate seepage-relevant, model-related parameters on the drift scale; (4) to estimate the epistemic uncertainty of the derived parameters, based on the goodness-of-fit to the observed data and the sensitivity of calculated seepage with respect to the parameters of interest; (5) to characterize the aleatory uncertainty
Proton beam monitor chamber calibration
International Nuclear Information System (INIS)
Gomà, C; Meer, D; Safai, S; Lorentini, S
The first goal of this paper is to clarify the reference conditions for the reference dosimetry of clinical proton beams. A clear distinction is made between proton beam delivery systems which should be calibrated with a spread-out Bragg peak field and those that should be calibrated with a (pseudo-)monoenergetic proton beam. For the latter, this paper also compares two independent dosimetry techniques to calibrate the beam monitor chambers: absolute dosimetry (of the number of protons exiting the nozzle) with a Faraday cup and reference dosimetry (i.e. determination of the absorbed dose to water under IAEA TRS-398 reference conditions) with an ionization chamber. To compare the two techniques, Monte Carlo simulations were performed to convert dose-to-water to proton fluence. A good agreement was found between the Faraday cup technique and the reference dosimetry with a plane-parallel ionization chamber. The differences—of the order of 3%—were found to be within the uncertainty of the comparison. For cylindrical ionization chambers, however, the agreement was only possible when positioning the effective point of measurement of the chamber at the reference measurement depth—i.e. not complying with IAEA TRS-398 recommendations. In conclusion, for cylindrical ionization chambers, IAEA TRS-398 reference conditions for monoenergetic proton beams led to a systematic error in the determination of the absorbed dose to water, especially relevant for low-energy proton beams. To overcome this problem, the effective point of measurement of cylindrical ionization chambers should be taken into account when positioning the reference point of the chamber. Within the current IAEA TRS-398 recommendations, it seems advisable to use plane-parallel ionization chambers—rather than cylindrical chambers—for the reference dosimetry of pseudo-monoenergetic proton beams. (paper)
Online examiner calibration across specialties.
Sturman, Nancy; Wong, Wai Yee; Turner, Jane; Allan, Chris
Integrating undergraduate medical curricula horizontally across clinical medical specialties may be a more patient-centred and learner-centred approach than rotating students through specialty-specific teaching and assessment, but requires some interspecialty calibration of examiner judgements. Our aim was to evaluate the acceptability and feasibility of an online pilot of interdisciplinary examiner calibration. Fair clinical assessment is important to both medical students and clinical teachers METHODS: Clinical teachers were invited to rate video-recorded student objective structured clinical examination (OSCE) performances and join subsequent online discussions using the university's learning management system. Post-project survey free-text and Likert-scale participant responses were analysed to evaluate the acceptability of the pilot and to identify recommendations for improvement. Although 68 clinicians were recruited to participate, and there were 1599 hits on recordings and discussion threads, only 25 clinical teachers rated at least one student performance, and 18 posted at least one comment. Participants, including rural doctors, appeared to value the opportunity for interdisciplinary rating calibration and discussion. Although the asynchronous online format had advantages, especially for rural doctors, participants reported considerable IT challenges. Our findings suggest that fair clinical assessment is important to both medical students and clinical teachers. Interspecialty discussions about assessment may have the potential to enrich intraspecialty perspectives, enhance interspecialty engagement and collaboration, and improve the quality of clinical teacher assessment. Better alignment of university and hospital systems, a face to face component and other modifications may have enhanced clinician engagement with this project. Findings suggest that specialty assessment cultures and content expertise may not be barriers to pursuing more integrated
Programming effort analysis of the ELLPACK language
Rice, J. R.
ELLPACK is a problem statement language and system for elliptic partial differential equations which is implemented by a FORTRAN preprocessor. ELLPACK's principal purpose is as a tool for the performance evaluation of software. However, it is used here as an example with which to study the programming effort required for problem solving. It is obvious that problem statement languages can reduce programming effort tremendously; the goal is to quantify this somewhat. This is done by analyzing the lengths and effort (as measured by Halstead's software science technique) of various approaches to solving these problems.
Laboratory panel and radiometer calibration
CSIR Research Space (South Africa)
Deadman, AJ
Full Text Available stream_source_info Griffith1_2011.pdf.txt stream_content_type text/plain stream_size 16659 Content-Encoding ISO-8859-1 stream_name Griffith1_2011.pdf.txt Content-Type text/plain; charset=ISO-8859-1 LABORATORY PANEL... of Land surface imaging through a ground reference standard test site?, on http://qa4eo.org/documentation.html, 2009. [2] K. J. Thome, D. L. Helder, D. Aaron, and J. D. Dewald, ?Landsat-5 TM and Landsat-7 ETM+ Absolute Radiometric Calibration Using...
A Cryogenic Infrared Calibration Target
Wollack, E. J.; Kinzer, R. E., Jr.; Rinehart, S. A.
A compact cryogenic calibration target is presented that has a peak diffuse reflectance, R target. The resulting target assembly is lightweight, has a low-geometric profile, and has survived repeated thermal cycling from room temperature to approx.4 K. Basic design considerations, governing equations, and test data for realizing the structure described are provided. The optical properties of selected absorptive materials-Acktar Fractal Black, Aeroglaze Z306, and Stycast 2850 FT epoxy loaded with stainless steel powder-are characterized and presented
International Nuclear Information System (INIS)
Stone, G.F.; Dittmore, C.H.; Henke, B.L.
This paper discusses the use of silver halide x-ray films for imaging and spectroscopy which is limited by the range of intensities that can be recorded and densitometered. Using the manufacturers processing techniques can result in 10 2-3 range in intensity recorded over 0-5 density range. By modifying the chemistry and processing times, ranges of 10 5-6 can be recorded in the same density range. The authors report on x-ray film calibration work and dynamic range improvements. Changes to the processing chemistry and the resulting changes in dynamic range and x-ray sensitivity are discussed
Calibration of TOB+ Thermometer's Cards
Banitt, Daniel
Motivation - Under the new upgrade of the CMS detector the working temperature of the trackers had been reduced to -27 Celsius degrees. Though the thermal sensors themselves (Murata and Fenwal thermistors) are effective at these temperatures, the max1542 PLC (programmable logic controller) cards, interpreting the resistance of the thermal sensors into DC counts usable by the DCS (detector control system), are not designed for these temperatures in which the counts exceed their saturation and therefor had to be replaced. In my project I was in charge of handling the emplacement and calibration of the new PLC cards to the TOB (tracker outer barrel) control system.
Illinois highway materials sustainability efforts of 2015.
This report provides a summary of the sustainability efforts of the Illinois Department of Transportation (IDOT) in recycling : reclaimed materials in highway construction during calendar year 2015. This report meets the requirements of Illinois Publ...
EU grid computing effort takes on malaria
Lawrence, Stacy
Malaria is the world's most common parasitic infection, affecting more thatn 500 million people annually and killing more than 1 million. In order to help combat malaria, CERN has launched a grid computing effort (1 page)
Illinois highway materials sustainability efforts of 2014.
This report presents the 2014 sustainability efforts of the Illinois Department of Transportation (IDOT) in : recycling reclaimed materials in highway construction. This report meets the requirements of Illinois : Public Act 097-0314 by documenting I...
Illinois highway materials sustainability efforts of 2016.
This report provides a summary of the sustainability efforts of the Illinois Department of Transportation (IDOT) in recycling : reclaimed materials in highway construction during calendar year 2016. This report meets the requirements of Illinois Publ...
Illinois highway materials sustainability efforts of 2013.
This report presents the sustainability efforts of the Illinois Department of Transportation (IDOT) in : recycling and reclaiming materials for use in highway construction. This report meets the requirements of : Illinois Public Act 097-0314 by docum...
Standard Test Method for Calibration of Non-Concentrator Photovoltaic Secondary Reference Cells
American Society for Testing and Materials. Philadelphia
1.1 This test method covers calibration and characterization of secondary terrestrial photovoltaic reference cells to a desired reference spectral irradiance distribution. The recommended physical requirements for these reference cells are described in Specification E1040. Reference cells are principally used in the determination of the electrical performance of a photovoltaic device. 1.2 Secondary reference cells are calibrated indoors using simulated sunlight or outdoors in natural sunlight by reference to a primary reference cell previously calibrated to the same desired reference spectral irradiance distribution. 1.3 Secondary reference cells calibrated according to this test method will have the same radiometric traceability as the of the primary reference cell used for the calibration. Therefore, if the primary reference cell is traceable to the World Radiometric Reference (WRR, see Test Method E816), the resulting secondary reference cell will also be traceable to the WRR. 1.4 This test method appli...
Genetic Algorithm Calibration of Probabilistic Cellular Automata for Modeling Mining Permit Activity
Louis, S.J.; Raines, G.L.
We use a genetic algorithm to calibrate a spatially and temporally resolved cellular automata to model mining activity on public land in Idaho and western Montana. The genetic algorithm searches through a space of transition rule parameters of a two dimensional cellular automata model to find rule parameters that fit observed mining activity data. Previous work by one of the authors in calibrating the cellular automaton took weeks - the genetic algorithm takes a day and produces rules leading to about the same (or better) fit to observed data. These preliminary results indicate that genetic algorithms are a viable tool in calibrating cellular automata for this application. Experience gained during the calibration of this cellular automata suggests that mineral resource information is a critical factor in the quality of the results. With automated calibration, further refinements of how the mineral-resource information is provided to the cellular automaton will probably improve our model.
Pulse-based internal calibration of polarimetric SAR
DEFF Research Database (Denmark)
Dall, Jørgen; Skou, Niels; Christensen, Erik Lintz
Internal calibration greatly diminishes the dependence on calibration target deployment compared to external calibration. Therefore the Electromagnetics Institute (EMI) at the Technical University of Denmark (TUD) has equipped its polarimetric SAR, EMISAR, with several calibration loops and devel......Internal calibration greatly diminishes the dependence on calibration target deployment compared to external calibration. Therefore the Electromagnetics Institute (EMI) at the Technical University of Denmark (TUD) has equipped its polarimetric SAR, EMISAR, with several calibration loops...
Calibrating cellular automaton models for pedestrians walking through corners
Dias, Charitha; Lovreglio, Ruggiero
Cellular Automata (CA) based pedestrian simulation models have gained remarkable popularity as they are simpler and easier to implement compared to other microscopic modeling approaches. However, incorporating traditional floor field representations in CA models to simulate pedestrian corner navigation behavior could result in unrealistic behaviors. Even though several previous studies have attempted to enhance CA models to realistically simulate pedestrian maneuvers around bends, such modifications have not been calibrated or validated against empirical data. In this study, two static floor field (SFF) representations, namely 'discrete representation' and 'continuous representation', are calibrated for CA-models to represent pedestrians' walking behavior around 90° bends. Trajectory data collected through a controlled experiment are used to calibrate these model representations. Calibration results indicate that although both floor field representations can represent pedestrians' corner navigation behavior, the 'continuous' representation fits the data better. Output of this study could be beneficial for enhancing the reliability of existing CA-based models by representing pedestrians' corner navigation behaviors more realistically.
Dosemeter calibration in X-ray and in cobalt-60
International Nuclear Information System (INIS)
Silva, T.A. da
Some tests about quality security for clinical dosemeter calibration in secondary standard dosimetry laboratory are described. The tests in gama calibration system, in X-ray calibration, in secondary standard dosimeter, in the dosemeter that will be calibrated, during the calibration and after the calibration are shown. (C.G.C.) [pt
Another look at volume self-calibration: calibration and self-calibration within a pinhole model of Scheimpflug cameras
International Nuclear Information System (INIS)
Cornic, Philippe; Le Besnerais, Guy; Champagnat, Frédéric; Illoul, Cédric; Cheminet, Adam; Le Sant, Yves; Leclaire, Benjamin
We address calibration and self-calibration of tomographic PIV experiments within a pinhole model of cameras. A complete and explicit pinhole model of a camera equipped with a 2-tilt angles Scheimpflug adapter is presented. It is then used in a calibration procedure based on a freely moving calibration plate. While the resulting calibrations are accurate enough for Tomo-PIV, we confirm, through a simple experiment, that they are not stable in time, and illustrate how the pinhole framework can be used to provide a quantitative evaluation of geometrical drifts in the setup. We propose an original self-calibration method based on global optimization of the extrinsic parameters of the pinhole model. These methods are successfully applied to the tomographic PIV of an air jet experiment. An unexpected by-product of our work is to show that volume self-calibration induces a change in the world frame coordinates. Provided the calibration drift is small, as generally observed in PIV, the bias on the estimated velocity field is negligible but the absolute location cannot be accurately recovered using standard calibration data. (paper)
Calibration Laboratory for Medical Physics towards ISO/ IEC 17025 accreditation: Experience and challenges
International Nuclear Information System (INIS)
Asmaliza Hashim; Abdul Aziz Ramli; Muhammad Jamal Isa; Sharul Azlan Azizan
Medical Physics Calibration Laboratory is laboratory where placed under Medical Physics Group, Radiation Healthy and Safety Division. This laboratory offers calibration services to their customers that covered doses calibration, tube voltan (kVp), exposure doses, sensitometer and densitometer. After 12 years of operation, it is the right time for this laboratory to upgrade their quality services based on ISO/ IEC 17025. Accreditation scope covered calibration for diagnostic doses only. Starting from 2009, serious effort was done to prepare the quality documents that covered quality manual, quality procedure and work orders. Meanwhile, several series of audit were done by Quality Management Center (QMC), now Innovation Management Center (IMC) with collaboration with Standard Department. This paper works revealed challenges and experience during the process toward ISO/ IEC 17025 accreditation. (author)
Development of composite calibration standard for quantitative NDE by ultrasound and thermography
Dayal, Vinay; Benedict, Zach G.; Bhatnagar, Nishtha; Harper, Adam G.
Inspection of aircraft components for damage utilizing ultrasonic Non-Destructive Evaluation (NDE) is a time intensive endeavor. Additional time spent during aircraft inspections translates to added cost to the company performing them, and as such, reducing this expenditure is of great importance. There is also great variance in the calibration samples from one entity to another due to a lack of a common calibration set. By characterizing damage types, we can condense the required calibration sets and reduce the time required to perform calibration while also providing procedures for the fabrication of these standard sets. We present here our effort to fabricate composite samples with known defects and quantify the size and location of defects, such as delaminations, and impact damage. Ultrasonic and Thermographic images are digitally enhanced to accurately measure the damage size. Ultrasonic NDE is compared with thermography.
Predictive error dependencies when using pilot points and singular value decomposition in groundwater model calibration
DEFF Research Database (Denmark)
Christensen, Steen; Doherty, John
super parameters), and that the structural errors caused by using pilot points and super parameters to parameterize the highly heterogeneous log-transmissivity field can be significant. For the test case much effort is put into studying how the calibrated model's ability to make accurate predictions...
A novel approach for absolute radar calibration: formulation and theoretical validation
Directory of Open Access Journals (Sweden)
C. Merker
Full Text Available The theoretical framework of a novel approach for absolute radar calibration is presented and its potential analysed by means of synthetic data to lay out a solid basis for future practical application. The method presents the advantage of an absolute calibration with respect to the directly measured reflectivity, without needing a previously calibrated reference device. It requires a setup comprising three radars: two devices oriented towards each other, measuring reflectivity along the same horizontal beam and operating within a strongly attenuated frequency range (e.g. K or X band, and one vertical reflectivity and drop size distribution (DSD profiler below this connecting line, which is to be calibrated. The absolute determination of the calibration factor is based on attenuation estimates. Using synthetic, smooth and geometrically idealised data, calibration is found to perform best using homogeneous precipitation events with rain rates high enough to ensure a distinct attenuation signal (reflectivity above ca. 30 dBZ. Furthermore, the choice of the interval width (in measuring range gates around the vertically pointing radar, needed for attenuation estimation, is found to have an impact on the calibration results. Further analysis is done by means of synthetic data with realistic, inhomogeneous precipitation fields taken from measurements. A calibration factor is calculated for each considered case using the presented method. Based on the distribution of the calculated calibration factors, the most probable value is determined by estimating the mode of a fitted shifted logarithmic normal distribution function. After filtering the data set with respect to rain rate and inhomogeneity and choosing an appropriate length of the considered attenuation path, the estimated uncertainty of the calibration factor is of the order of 1 to 11 %, depending on the chosen interval width. Considering stability and accuracy of the method, an interval of
New method to calibrate a spinner anemometer
DEFF Research Database (Denmark)
Demurtas, Giorgio; Friis Pedersen, Troels
The spinner anemometer is a wind sensor, based on three one dimensional sonic sensor probes, mounted on the wind turbine spinner, and an algorithm to convert the wind speeds measured by the three sonic sensors to horizontal wind speed, yaw misalignment and flow inclination angle. The conversion...... algorithm utilizes two constants k1 and k2 that are specific to the spinner and blade root design and to the mounting position of the sonic sensors on the spinner. The two constants are calibrated by means of two different test and instrument set-ups. Both calibrations consider the rotor of the wind turbine...... to be stopped during calibration in order for the rotor induction not to influence on the calibration, so that the spinner anemometer measures "free" wind values in stopped condition. The calibration of flow angle measurements is made by calibration of the ratio of the two algorithm constants k2=k1 = k...
Linear Calibration – Is It so Simple?
International Nuclear Information System (INIS)
Arsova, Diana; Babanova, Sofia; Mandjukov, Petko
Calibration procedure is an important part of instrumental analysis. Usually it is not the major uncertainty source in whole analytical procedure. However, improper calibration might cause a significant bias of the analytical results from the real (certified) value. Standard Gaussian linear regression is the most frequently used mathematical approach for estimation of calibration function parameters. In the present article are discussed some not quite popular, but highly recommended in certain cases methods for parameter estimation, such as: weighted regression, orthogonal regression, robust regression, bracketing calibration etc. Some useful approximations are also presented. Special attention is paid to the statistical criteria which to be used for selection of proper calibration model. Standard UV-VIS spectrometric procedure for determination of phosphates in water was used as a practical example. Several different approaches for estimation of the contribution of calibration to the general un-certainty of the analytical result are presented and compared
An innovative method to calibrate a spinner anemometer without the use of yaw position sensor
Directory of Open Access Journals (Sweden)
G. Demurtas
Full Text Available A spinner anemometer can be used to measure the yaw misalignment and flow inclination experienced by a wind turbine. Previous calibration methods used to calibrate a spinner anemometer for flow angle measurements were based on measurements of a spinner anemometer with default settings (arbitrary values, generally k1,d = 1 and k2,d = 1 and a reference yaw misalignment signal measured with a yaw position sensor. The yaw position sensor is normally present in wind turbines for control purposes; however, such a signal is not always available for a spinner anemometer calibration. Therefore, an additional yaw position sensor was installed prior to the spinner anemometer calibration. An innovative method to calibrate the spinner anemometer without a yaw positions sensor was then developed. It was noted that a non-calibrated spinner anemometer that overestimates (underestimates the inflow angle will also overestimate (underestimate the wind speed when there is a yaw misalignment. The new method leverages the non-linearity of the spinner anemometer algorithm to find the calibration factor Fα by an optimization process that minimizes the dependency of the wind speed on the yaw misalignment. The new calibration method was found to be rather robust, with Fα values within ±2.7 % of the mean value for four successive tests at the same rotor position.
VIIRS reflective solar bands on-orbit calibration and performance: a three-year update
Sun, Junqiang; Wang, Menghua
The on-orbit calibration of the reflective solar bands (RSBs) of VIIRS and the result from the analysis of the up-to-date 3 years of mission data are presented. The VIIRS solar diffuser (SD) and lunar calibration methodology are discussed, and the calibration coefficients, called F-factors, for the RSBs are given for the latest reincarnation. The coefficients derived from the two calibrations are compared and the uncertainties of the calibrations are discussed. Numerous improvements are made, with the major improvement to the calibration result come mainly from the improved bidirectional reflectance factor (BRF) of the SD and the vignetting functions of both the SD screen and the sun-view screen. The very clean results, devoid of many previously known noises and artifacts, assures that VIIRS has performed well for the three years on orbit since launch, and in particular that the solar diffuser stability monitor (SDSM) is functioning essentially without flaws. The SD degradation, or H-factors, for most part shows the expected decline except for the surprising rise on day 830 lasting for 75 days signaling a new degradation phenomenon. Nevertheless the SDSM and the calibration methodology have successfully captured the SD degradation for RSB calibration. The overall improvement has the most significant and direct impact on the ocean color products which demands high accuracy from RSB observations.
Matching Images to Models: Camera Calibration for 3-D Surface Reconstruction
Morris, Robin D.; Smelyanskiy, Vadim N.; Cheeseman. Peter C.; Norvig, Peter (Technical Monitor)
In a previous paper we described a system which recursively recovers a super-resolved three dimensional surface model from a set of images of the surface. In that paper we assumed that the camera calibration for each image was known. In this paper we solve two problems. Firstly, if an estimate of the surface is already known, the problem is to calibrate a new image relative to the existing surface model. Secondly, if no surface estimate is available, the relative camera calibration between the images in the set must be estimated. This will allow an initial surface model to be estimated. Results of both types of estimation are given.
Radiocarbon calibration - past, present and future
Energy Technology Data Exchange (ETDEWEB)
Plicht, J. van der E-mail: firstname.lastname@example.com
Calibration of the Radiocarbon timescale is traditionally based on tree-rings dated by dendrochronology. At present, the tree-ring curve dates back to about 9900 BC. Beyond this limit, marine datasets extend the present calibration curve INTCAL98 to about 15 600 years ago. Since 1998, a wealth of AMS measurements became available, covering the complete {sup 14}C dating range. No calibration curve can presently be recommended for the older part of the dating range until discrepancies are resolved.
Radiocarbon calibration - past, present and future
International Nuclear Information System (INIS)
Plicht, J. van der
Calibration of the Radiocarbon timescale is traditionally based on tree-rings dated by dendrochronology. At present, the tree-ring curve dates back to about 9900 BC. Beyond this limit, marine datasets extend the present calibration curve INTCAL98 to about 15 600 years ago. Since 1998, a wealth of AMS measurements became available, covering the complete 14 C dating range. No calibration curve can presently be recommended for the older part of the dating range until discrepancies are resolved
ATLAS FCal Diagnostics using the Calibration Pulse
Rutherfoord, J
The calibration pulser in the ATLAS Forward Calorimeter electronics is used to 1) directly calibrate the warm, active electronics and 2) diagnose the cold, passive electronics chain all the way to the liquid argon electrodes. The study presented here shows that reflections of the calibration pulse coming from discontinuities located at or between the warm preamplifier and the electrode can differentiate and identify all known defects so far observed in this chain.
Observatory Magnetometer In-Situ Calibration
Directory of Open Access Journals (Sweden)
A Marusenkov
Full Text Available An experimental validation of the in-situ calibration procedure, which allows estimating parameters of observatory magnetometers (scale factors, sensor misalignment without its operation interruption, is presented. In order to control the validity of the procedure, the records provided by two magnetometers calibrated independently in a coil system have been processed. The in-situ estimations of the parameters are in very good agreement with the values provided by the coil system calibration.
Calibration method for a radwaste assay system
International Nuclear Information System (INIS)
Dulama, C.; Dobrin, R.; Toma, Al.; Paunoiu, C.
A waste assay system entirely designed and manufactured in the Institute for Nuclear Research is used in radwaste treatment and conditioning stream to ensure compliance with national repository radiological requirements. Usually, waste assay systems are calibrated by using various experimental arrangements including calibration phantoms. The paper presents a comparative study concerning the efficiency calibration performed by shell source method and a semiempirical, computational method based on a Monte Carlo algorithm. (authors)
1987 calibration of the TFTR neutron spectrometers
International Nuclear Information System (INIS)
Barnes, C.W.; Strachan, J.D.; Princeton Univ., NJ
The 3 He neutron spectrometer used for measuring ion temperatures and the NE213 proton recoil spectrometer used for triton burnup measurements were absolutely calibrated with DT and DD neutron generators placed inside the TFTR vacuum vessel. The details of the detector response and calibration are presented. Comparisons are made to the neutron source strengths measured from other calibrated systems. 23 refs., 19 figs., 6 tabs
Effective radiation attenuation calibration for breast density: compression thickness influences and correction
Thomas Jerry A; Cao Ke; Heine John J
Abstract Background Calibrating mammograms to produce a standardized breast density measurement for breast cancer risk analysis requires an accurate spatial measure of the compressed breast thickness. Thickness inaccuracies due to the nominal system readout value and compression paddle orientation induce unacceptable errors in the calibration. Method A thickness correction was developed and evaluated using a fully specified two-component surrogate breast model. A previously developed calibrat...
Detector calibration measurements in CRESST
Energy Technology Data Exchange (ETDEWEB)
Westphal, W. [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany)]. E-mail: firstname.lastname@example.com; Coppi, C. [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany); Feilitzsch, F. von [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany); Isaila, C. [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany); Jagemann, T. [Eberhard Karls Universitaet Tuebingen, Physikalisches Institut I, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany); Jochum, J. [Eberhard Karls Universitaet Tuebingen, Physikalisches Institut I, Auf der Morgenstelle 14, D-72076 Tuebingen (Germany); Koenig, J. [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany); Lachenmaier, T. [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany); Lanfranchi, J.-C. [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany); Potzel, W. [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany); Rau, W. [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany); Stark, M. [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany); Wernicke, D. [Technische Universitaet Muenchen, Physik Department E15, James-Franck-Strasse, D-85748 Garching (Germany); VeriCold Technologies GmbH, Bahnhofstrasse 21, D-85737 Ismaning (Germany)
The CRESST dark matter experiment uses the simultaneous measurement of the scintillation light and the heat signal of a CaWO{sub 4} crystal to discriminate between background electron recoil and nuclear recoil events. At the Technical University of Munich calibration measurements have been performed to characterize the detectors. These measurements include the determination of the light output and scintillation time constants of CaWO{sub 4} at temperatures below 50 mK. The setup used in these measurements consist of a CaWO{sub 4} crystal, which is mounted in a reflective housing together with a silicon light detector carrying an Ir/Au transition edge sensor (TES) evaporated directly onto it.
Calibration of acoustic emission transducers
International Nuclear Information System (INIS)
Leschek, W.C.
A method is described for calibrating an acoustic emission transducer to be used in a pre-set frequency range. The absolute reception sensitivity of a reference transducer is determined at frequencies selected within the frequency range. The reference transducer and the acoustic emission transducer are put into acoustic communication with the surface of a limited acoustic medium representing an equivalent acoustic load appreciably identical to that of the medium in which the use of the acoustic emission transducer is intended. A blank random acoustic noise is emitted in the acoustic medium in order to establish a diffuse and reverberating sound field, after which the output responses of the reference transducer and of the acoustic emission transducer are obtained with respect to the diffuse and reverberating field, for selected frequencies. The output response of the acoustic emission transducer is compared with that of the reference transducer for the selected frequencies, so as to determine the reception sensitivity of the acoustic emission transducer [fr
Calibration of Nuclear Track Detectors
International Nuclear Information System (INIS)
Vukovic, J.B; Antanasijevic, R.; Novakovic, V.; Tasic, M.
In this work we compare some of our preliminary results relating to the calibration Nuclear Track Detectors (NTD) with corresponding results obtained from other participants at the First International Intercomparison of Image Analyzers (III 97/98). Thirteen laboratories from Algeria, China, Czech Rep., France. Germany, Greece, Hungary, India, Italy, Mexico, Saudi Arabia, Slovenia and Yugoslavia participated in the III A 97/98. The NTD was 'Tustrack', Bristol. This type of CR-39 detector was etched by the organizer (J.Paltarey of al, Atomic Energy Research Institute, HPD, Budapest, Hungary). Etching condition was: 6N NaOH, 70 0C . Seven series detectors were exposed with the sources: B(n,a)Li, Am-241, Pu-Be(n,p), Radon and Am-Cm-Pu. Following parameters of exposed detectors were measured: track density of different sorts of tracks (circular, elliptical, track overlapping, their diameters, major and minor axis and other). (authors)
Calibration and check light source
Energy Technology Data Exchange (ETDEWEB)
Nejedla, B; Krotil, J
The light source is designed for calibrating photomultipliers and checking the function of the thermoluminescent dosemeters evaluation equipment. The check light source consists of a polymer material-based (polyvinyl toluene) plastic scintillator and a 2-phenyl-5-(4-bisphenyl)-1,3,4-oxadiazol and/or paraterphenyl activator, and of emission spectrum shifters for response in the green and the blue light regions. The plastic scintillator is sealed in a case to whose bottom a radiation source is fixed, such as a /sup 90/Sr-/sup 90/Y source of an activity of 1.85x10/sup 3/s/sup -1/ to 0.74x10/sup 9/s/sup -1/.
Gearbox Reliability Collaborative Bearing Calibration
Energy Technology Data Exchange (ETDEWEB)
van Dam, J.
NREL has initiated the Gearbox Reliability Collaborative (GRC) to investigate the root cause of the low wind turbine gearbox reliability. The GRC follows a multi-pronged approach based on a collaborative of manufacturers, owners, researchers and consultants. The project combines analysis, field testing, dynamometer testing, condition monitoring, and the development and population of a gearbox failure database. At the core of the project are two 750kW gearboxes that have been redesigned and rebuilt so that they are representative of the multi-megawatt gearbox topology currently used in the industry. These gearboxes are heavily instrumented and are tested in the field and on the dynamometer. This report discusses the bearing calibrations of the gearboxes.
The Dark Energy Survey Data Processing and Calibration System
Energy Technology Data Exchange (ETDEWEB)
Mohr, Joseph J. [Munich U.; Armstrong, Robert [Penn State U.; Bertin, Emmanuel [Paris, Inst. Astrophys.; Daues, Gregory E. [NCSA, Urbana; Desai, Shantanu [Munich U.; Gower, Michelle [NCSA, Urbana; Gruendl, Robert [Illinois U., Urbana (main); Hanlon, William [Illinois U., Urbana (main); Kuropatkin, Nikolay [Fermilab; Lin, Huan [Fermilab; Marriner, John [Fermilab; Petravick, Don; Sevilla, Ignacio [Madrid, CIEMAT; Swanson, Molly [Harvard-Smithsonian Ctr. Astrophys.; Tomashek, Todd [NCSA, Urbana; Tucker, Douglas [Fermilab; Yanny, Brian [Fermilab
The Dark Energy Survey (DES) is a 5000 deg2 grizY survey reaching characteristic photometric depths of 24th magnitude (10 sigma) and enabling accurate photometry and morphology of objects ten times fainter than in SDSS. Preparations for DES have included building a dedicated 3 deg2 CCD camera (DECam), upgrading the existing CTIO Blanco 4m telescope and developing a new high performance computing (HPC) enabled data management system (DESDM). The DESDM system will be used for processing, calibrating and serving the DES data. The total data volumes are high (~2PB), and so considerable effort has gone into designing an automated processing and quality control system. Special purpose image detrending and photometric calibration codes have been developed to meet the data quality requirements, while survey astrometric calibration, coaddition and cataloging rely on new extensions of the AstrOmatic codes which now include tools for PSF modeling, PSF homogenization, PSF corrected model fitting cataloging and joint model fitting across multiple input images. The DESDM system has been deployed on dedicated development clusters and HPC systems in the US and Germany. An extensive program of testing with small rapid turn-around and larger campaign simulated datasets has been carried out. The system has also been tested on large real datasets, including Blanco Cosmology Survey data from the Mosaic2 camera. In Fall 2012 the DESDM system will be used for DECam commissioning, and, thereafter, the system will go into full science operations.
Optical calibration and test of the VLT Deformable Secondary Mirror
Briguglio, Runa; Xompero, Marco; Riccardi, Armando; Andrighettoni, Mario; Pescoller, Dietrich; Biasi, Roberto; Gallieni, Daniele; Vernet, Elise; Kolb, Johann; Arsenault, Robin; Madec, Pierre-Yves
The Deformable Secondary Mirror (DSM) for the VLT (ESO) represents the state-of-art of the large-format deformable mirror technology with its 1170 voice-coil actuators and its internal metrology based on actuator co-located capacitive sensors to control the shape of the 1.12m-diameter 2mm-thick convex shell. The present paper reports the results of the optical characterization of the mirror unit with the ASSIST facility located at ESO-Garching and executed in a collaborative effort by ESO, INAF-Osservatorio Astrofisico di Arcetri and the DSM manufacturing companies (Microgate s.r.l. and A.D.S. International s.r.l.). The main purposes of the tests are the optical characterization of the shell flattening residuals, the corresponding calibration of flattening commands, the optical calibration of the capacitive sensors and the optical calibration of the mirror influence functions. The results are used for the optical acceptance of the DSM and to allow the next test phase coupling the DSM with the wave-front sensor modules of the new Adaptive Optics Facility (AOF) of ESO.
Status of ionization chambers calibration for radiation therapy in Brazil
Gonçalves, M.; Joana, G.; Leal, P.; Vasconcelos, R.; do Couto, N.; Teixeira, F. C.; Soares, A. D.; Santini, E. S.; Salata, C.
CNEN makes a constant effort to keep updated with international standards and national needs to strengthen the radiological protection status of the country. The guidelines related to radiation treatment facilities have been revised in the last five years in order to take in consideration the most relevant aspects of the growing technology as well as to mitigate the accidents or incidents observed in practice. Hence, clinical dosimeters have gained special importance as significant items in Brazilian regulation. In the present work we discuss the importance of inspections from the point of view of equipment dosimetry and instruments quality control. The dosimeter sets based on thimble and well ionization chambers need periodic calibration, and this calibration becomes a fundamental task in order to guarantee the dose prescribed-delivered to patients. Thus Brazilian guidelines enforce the need of at least two sets of clinical dosimeters with thimble chambers calibrated and one set of electrometer with well ionization chamber for hdr equipment. We call attention to the fact that inspections are a very valuable tool in order to enforce the application of guidelines around the country both by enlightening the weaker aspects of facilities concerning radiological protection and by stating in loco that reasons which lead the regulatory body to enforce such guidelines items.
DEM Calibration Approach: design of experiment
Boikov, A. V.; Savelev, R. V.; Payor, V. A.
The problem of DEM models calibration is considered in the article. It is proposed to divide models input parameters into those that require iterative calibration and those that are recommended to measure directly. A new method for model calibration based on the design of the experiment for iteratively calibrated parameters is proposed. The experiment is conducted using a specially designed stand. The results are processed with technical vision algorithms. Approximating functions are obtained and the error of the implemented software and hardware complex is estimated. The prospects of the obtained results are discussed.
Fuel conditioning facility electrorefiner volume calibration
International Nuclear Information System (INIS)
Bucher, R.G.; Orechwa, Y.
In one of the electrometallurgical process steps of the Fuel Conditioning Facility (FCF), die in-process nuclear material is dissolved in the electrorefiner tank in an upper layer of a mixture of liquid LiCl-KCl salt and a lower layer of liquid cadmium. The electrorefiner tank, as most process tanks, is not a smooth right-circular cylinder for which a single linear volume calibration curve could be fitted over the whole height of the tank. Rather, the tank contains many internal components, which cause systematic deviations from a single linear function. The nominal operating temperature of the electrorefiner is 500 degrees C although the salt and cadmium are introduced at 410 degrees C. The operating materials and temperatures preclude multiple calibration runs at operating conditions. In order to maximize the calibration information, multiple calibration runs were performed with water at room temperature. These data allow identification of calibration segments, and preliminary estimation of the calibration function and calibration uncertainties. The final calibration function is based on a combination of data from die water calibrations and the measurements made during the filling of the electrorefiner with salt and cadmium for operation
Calibration services for medical applications of radiation
Energy Technology Data Exchange (ETDEWEB)
DeWerd, L.A.
Calibration services for the medical community applications of radiation involve measuring radiation precisely and having traceability to the National Institute of Standards and Technology (NIST). Radiation therapy applications involve the use of ionization chambers and electrometers for external beams and well-type ionization chamber systems as well as radioactive sources for brachytherapy. Diagnostic x-ray applications involve ionization chamber systems and devices to measure other parameters of the x-ray machine, such as non-invasive kVp meters. Calibration laboratories have been established to provide radiation calibration services while maintaining traceability to NIST. New radiation applications of the medical community spur investigation to provide the future calibration needs.
Sloan Digital Sky Survey Photometric Calibration Revisited
International Nuclear Information System (INIS)
Marriner, John
The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.
Immune Algorithm Complex Method for Transducer Calibration
Directory of Open Access Journals (Sweden)
YU Jiangming
Full Text Available As a key link in engineering test tasks, the transducer calibration has significant influence on accuracy and reliability of test results. Because of unknown and complex nonlinear characteristics, conventional method can't achieve satisfactory accuracy. An Immune algorithm complex modeling approach is proposed, and the simulated studies on the calibration of third multiple output transducers is made respectively by use of the developed complex modeling. The simulated and experimental results show that the Immune algorithm complex modeling approach can improve significantly calibration precision comparison with traditional calibration methods.
Calibration services for medical applications of radiation
International Nuclear Information System (INIS)
DeWerd, L.A.
Calibration services for the medical community applications of radiation involve measuring radiation precisely and having traceability to the National Institute of Standards and Technology (NIST). Radiation therapy applications involve the use of ionization chambers and electrometers for external beams and well-type ionization chamber systems as well as radioactive sources for brachytherapy. Diagnostic x-ray applications involve ionization chamber systems and devices to measure other parameters of the x-ray machine, such as non-invasive kVp meters. Calibration laboratories have been established to provide radiation calibration services while maintaining traceability to NIST. New radiation applications of the medical community spur investigation to provide the future calibration needs
Sloan Digital Sky Survey Photometric Calibration Revisited
Energy Technology Data Exchange (ETDEWEB)
Marriner, John; /Fermilab
The Sloan Digital Sky Survey calibration is revisited to obtain the most accurate photometric calibration. A small but significant error is found in the flat-fielding of the Photometric telescope used for calibration. Two SDSS star catalogs are compared and the average difference in magnitude as a function of right ascension and declination exhibits small systematic errors in relative calibration. The photometric transformation from the SDSS Photometric Telescope to the 2.5 m telescope is recomputed and compared to synthetic magnitudes computed from measured filter bandpasses.
Model- and calibration-independent test of cosmic acceleration
International Nuclear Information System (INIS)
Seikel, Marina; Schwarz, Dominik J.
We present a calibration-independent test of the accelerated expansion of the universe using supernova type Ia data. The test is also model-independent in the sense that no assumptions about the content of the universe or about the parameterization of the deceleration parameter are made and that it does not assume any dynamical equations of motion. Yet, the test assumes the universe and the distribution of supernovae to be statistically homogeneous and isotropic. A significant reduction of systematic effects, as compared to our previous, calibration-dependent test, is achieved. Accelerated expansion is detected at significant level (4.3σ in the 2007 Gold sample, 7.2σ in the 2008 Union sample) if the universe is spatially flat. This result depends, however, crucially on supernovae with a redshift smaller than 0.1, for which the assumption of statistical isotropy and homogeneity is less well established
Calibration of the BASS acoustic current meter with carrageenan agar
Morrison, A.T.; Williams, A.J.; Martini, M.
The BASS current meter can measure currents down to the millimeter per second range. Due to the dependence of zero offset on pressure, determining a sensor referenced velocity requires accurate in situ zeroing of the meter. Previously, flow was restricted during calibration by placing plastic bags around the acoustic volume. In this paper, bacterial grade and carrageenan agars are used in the laboratory to create a zero flow condition during calibration and are shown to be acoustically transparent. Additionally, the results of open ocean and dockside carrageenan and plastic bag comparisons are presented. Carrageenan is shown to reliably provide a low noise, zero mean flow environment that is largely independent of ambient conditions. The improved zeros make millimeter per second accuracy possible under field conditions.
Calibration Plans for the Global Precipitation Measurement (GPM)
Bidwell, S. W.; Flaming, G. M.; Adams, W. J.; Everett, D. F.; Mendelsohn, C. R.; Smith, E. A.; Turk, J.
The Global Precipitation Measurement (GPM) is an international effort led by the National Aeronautics and Space Administration (NASA) of the U.S.A. and the National Space Development Agency of Japan (NASDA) for the purpose of improving research into the global water and energy cycle. GPM will improve climate, weather, and hydrological forecasts through more frequent and more accurate measurement of precipitation world-wide. Comprised of U.S. domestic and international partners, GPM will incorporate and assimilate data streams from many spacecraft with varied orbital characteristics and instrument capabilities. Two of the satellites will be provided directly by GPM, the core satellite and a constellation member. The core satellite, at the heart of GPM, is scheduled for launch in November 2007. The core will carry a conical scanning microwave radiometer, the GPM Microwave Imager (GMI), and a two-frequency cross-track-scanning radar, the Dual-frequency Precipitation Radar (DPR). The passive microwave channels and the two radar frequencies of the core are carefully chosen for investigating the varying character of precipitation over ocean and land, and from the tropics to the high-latitudes. The DPR will enable microphysical characterization and three-dimensional profiling of precipitation. The GPM-provided constellation spacecraft will carry a GMI radiometer identical to that on the core spacecraft. This paper presents calibration plans for the GPM, including on-board instrument calibration, external calibration methods, and the role of ground validation. Particular emphasis is on plans for inter-satellite calibration of the GPM constellation. With its Unique instrument capabilities, the core spacecraft will serve as a calibration transfer standard to the GPM constellation. In particular the Dual-frequency Precipitation Radar aboard the core will check the accuracy of retrievals from the GMI radiometer and will enable improvement of the radiometer retrievals
Mechanisms of Biliary Plastic Stent Occlusion and Efforts at Prevention
Directory of Open Access Journals (Sweden)
Chang-Il Kwon
Full Text Available Biliary stenting via endoscopic retrograde cholangiopancreatography has greatly improved the quality of patient care over the last 30 years. Plastic stent occlusion limits the life span of such stents. Attempts to improve plastic stent patency duration have mostly failed. Metal stents (self-expandable metal stents [SEMSs] have therefore replaced plastic stents, especially for malignant biliary strictures. SEMS are at least 10 times more expensive than plastic stents. In this focused review, we will discuss basic mechanisms of plastic stent occlusion, along with a systematic summary of previous efforts and related studies to improve stent patency and potential new techniques to overcome existing limitations.
Calibration of hydrological models using flow-duration curves
Directory of Open Access Journals (Sweden)
I. K. Westerberg
Full Text Available The degree of belief we have in predictions from hydrologic models will normally depend on how well they can reproduce observations. Calibrations with traditional performance measures, such as the Nash-Sutcliffe model efficiency, are challenged by problems including: (1 uncertain discharge data, (2 variable sensitivity of different performance measures to different flow magnitudes, (3 influence of unknown input/output errors and (4 inability to evaluate model performance when observation time periods for discharge and model input data do not overlap. This paper explores a calibration method using flow-duration curves (FDCs to address these problems. The method focuses on reproducing the observed discharge frequency distribution rather than the exact hydrograph. It consists of applying limits of acceptability for selected evaluation points (EPs on the observed uncertain FDC in the extended GLUE approach. Two ways of selecting the EPs were tested – based on equal intervals of discharge and of volume of water. The method was tested and compared to a calibration using the traditional model efficiency for the daily four-parameter WASMOD model in the Paso La Ceiba catchment in Honduras and for Dynamic TOPMODEL evaluated at an hourly time scale for the Brue catchment in Great Britain. The volume method of selecting EPs gave the best results in both catchments with better calibrated slow flow, recession and evaporation than the other criteria. Observed and simulated time series of uncertain discharges agreed better for this method both in calibration and prediction in both catchments. An advantage with the method is that the rejection criterion is based on an estimation of the uncertainty in discharge data and that the EPs of the FDC can be chosen to reflect the aims of the modelling application, e.g. using more/less EPs at high/low flows. While the method appears less sensitive to epistemic input/output errors than previous use of limits of
Instruction Emphasizing Effort Improves Physics Problem Solving
Li, Daoquan
Effectively using strategies to solve complex problems is an important educational goal and is implicated in successful academic performance. However, people often do not spontaneously use the effective strategies unless they are motivated to do so. The present study was designed to test whether educating students about the importance of effort in…
Student Effort, Consistency, and Online Performance
Patron, Hilde; Lopez, Salvador
This paper examines how student effort, consistency, motivation, and marginal learning, influence student grades in an online course. We use data from eleven Microeconomics courses taught online for a total of 212 students. Our findings show that consistency, or less time variation, is a statistically significant explanatory variable, whereas…
Net benefits of wildfire prevention education efforts
Jeffrey P. Prestemon; David T. Butry; Karen L. Abt; Ronda Sutphen
Wildfire prevention education efforts involve a variety of methods, including airing public service announcements, distributing brochures, and making presentations, which are intended to reduce the occurrence of certain kinds of wildfires. A Poisson model of preventable Florida wildfires from 2002 to 2007 by fire management region was developed. Controlling for...
Has Malaysia's antidrug effort been effective?
Scorzelli, J F
It is a common belief that a massive effort in law enforcement, preventive education and rehabilitation will result in the elimination of a country's drug problem. Based on this premise. Malaysia in 1983 implemented such a multifaceted anti-drug strategy, and the results of a 1987 study by the author suggested that Malaysia's effort had begun to contribute to a steady decrease in the number of identified drug abusers. Although the number of drug-addicted individuals declined, the country's recidivism rates were still high. Because of this high relapse rate, Malaysia expanded their rehabilitation effort and developed a community transition program. In order to determine the impact of these changes on the country's battle against drug abuse, a follow-up study was conducted in 1990. The results of this study did not clearly demonstrate that the Malaysian effort had been successful in eliminating the problem of drug abuse, and raised some questions concerning the effectiveness of the country's drug treatment programs.
Phase transitions in least-effort communications
International Nuclear Information System (INIS)
Prokopenko, Mikhail; Ay, Nihat; Obst, Oliver; Polani, Daniel
We critically examine a model that attempts to explain the emergence of power laws (e.g., Zipf's law) in human language. The model is based on the principle of least effort in communications—specifically, the overall effort is balanced between the speaker effort and listener effort, with some trade-off. It has been shown that an information-theoretic interpretation of this principle is sufficiently rich to explain the emergence of Zipf's law in the vicinity of the transition between referentially useless systems (one signal for all referable objects) and indexical reference systems (one signal per object). The phase transition is defined in the space of communication accuracy (information content) expressed in terms of the trade-off parameter. Our study explicitly solves the continuous optimization problem, subsuming a recent, more specific result obtained within a discrete space. The obtained results contrast Zipf's law found by heuristic search (that attained only local minima) in the vicinity of the transition between referentially useless systems and indexical reference systems, with an inverse-factorial (sub-logarithmic) law found at the transition that corresponds to global minima. The inverse-factorial law is observed to be the most representative frequency distribution among optimal solutions
The Galileo Teacher Training Program Global Efforts
Doran, R.; Pennypacker, C.; Ferlet, R.
The Galileo Teacher Training Program (GTTP) successfully named representatives in nearly 100 nations in 2009, the International Year of Astronomy (IYA2009). The challenge had just begun. The steps ahead are how to reach educators that might benefit from our program and how to help build a more fair and science literate society, a society in which good tools and resources for science education are not the privilege of a few. From 2010 on our efforts have been to strengthen the newly formed network and learn how to equally help educators and students around the globe. New partnerships with other strong programs and institutions are being formed, sponsorship schemes being outlined, new tools and resources being publicized, and on-site and video conference training conducted all over the world. Efforts to officially accredit a GTTP curriculum are on the march and a stronger certification process being outlined. New science topics are being integrated in our effort and we now seek to discuss the path ahead with experts in this field and the community of users, opening the network to all corners of our beautiful blue dot. The main aim of this article is to open the discussion regarding the urgent issue of how to reawaken student interest in science, how to solve the gender inequality in science careers, and how to reach the underprivileged students and open to them the same possibilities. Efforts are in strengthening the newly formed network and learning how to equally help educators and students around the globe.
Effort - Final technical report on task 3
DEFF Research Database (Denmark)
Bay, Niels; Henningsen, Poul; Eriksen, Morten
The present report is documentation for the work carried out at DTU on the Brite/Euram project No. BE96-3340, contract No. BRPR-CT97-0398, with the title Enhanced Framework for forging design using reliable three-dimensional simulation (EFFORTS). The objective of task 3 is to determine data...
Hydrogen economy: a little bit more effort
International Nuclear Information System (INIS)
Pauron, M.
In few years, the use of hydrogen in economy has become a credible possibility. Today, billions of euros are invested in the hydrogen industry which is strengthened by technological advances in fuel cells development and by an increasing optimism. However, additional research efforts and more financing will be necessary to make the dream of an hydrogen-based economy a reality
Workplace High Tech Spurs Retraining Efforts.
Davis, Dwight B.
Discusses who should provide training for displaced workers who need new skills. Areas examined include: (1) the need for retraining; (2) current corporate efforts; (3) agreements in the automotive industry; (4) job quality; (5) the federal government's role; and (6) federal legislation related to the problem. (JN)
Testosterone and reproductive effort in male primates.
Muller, Martin N
Considerable evidence suggests that the steroid hormone testosterone mediates major life-history trade-offs in vertebrates, promoting mating effort at the expense of parenting effort or survival. Observations from a range of wild primates support the "Challenge Hypothesis," which posits that variation in male testosterone is more closely associated with aggressive mating competition than with reproductive physiology. In both seasonally and non-seasonally breeding species, males increase testosterone production primarily when competing for fecund females. In species where males compete to maintain long-term access to females, testosterone increases when males are threatened with losing access to females, rather than during mating periods. And when male status is linked to mating success, and dependent on aggression, high-ranking males normally maintain higher testosterone levels than subordinates, particularly when dominance hierarchies are unstable. Trade-offs between parenting effort and mating effort appear to be weak in most primates, because direct investment in the form of infant transport and provisioning is rare. Instead, infant protection is the primary form of paternal investment in the order. Testosterone does not inhibit this form of investment, which relies on male aggression. Testosterone has a wide range of effects in primates that plausibly function to support male competitive behavior. These include psychological effects related to dominance striving, analgesic effects, and effects on the development and maintenance of the armaments and adornments that males employ in mating competition. Copyright © 2016 Elsevier Inc. All rights reserved.
Reasonable limits to radiation protection efforts
International Nuclear Information System (INIS)
Gonen, Y.G.
It is shown that change in life expectancy (ΔLE) is an improved estimate for risks and safety efforts, reflecting the relevant social goal. A cost-effectiveness index, safety investment/ΔLE, is defined. The harm from low level radiation is seen as a reduction of life expectancy instead of an increased probability of contracting cancer. (author)
Instrument calibration reduction through on-line monitoring in the USA. Annex IV
International Nuclear Information System (INIS)
Hashemian, H.M.
Nuclear power plants are required to calibrate important instruments once every fuel cycle. This requirement dates back more than 30 years, when commercial nuclear power plants began to operate. Based on calibration data accumulated over this period, it has been determined that the calibration of some instruments, such as pressure transmitters, do not drift enough to warrant calibration as often as once every fuel cycle. This fact, combined with human resources limitations and reduced maintenance budgets, has provided the motivation for the nuclear industry to develop new technologies for identifying drifting instruments during plant operation. Implementing these technologies allows calibration efforts to be focused on the instruments that have drifted out of tolerance, as opposed to current practice, which calls for calibration verification of almost all instruments every fuel cycle. To date, an array of technologies, referred to collectively as 'on-line calibration monitoring', has been developed to meet this objective. These technologies are based on identifying outlier sensors using techniques that compare a particular sensor's output to a calculated estimate of the actual process the sensor is measuring. If on-line monitoring data are collected during plant startup and/or shutdown periods as well as normal operation, the on-line monitoring approach can help verify the calibration of instruments over their entire operating range. Although on-line calibration monitoring is applicable to most sensors and can cover an entire instrument channel, the main application of this approach in nuclear power plants is currently for pressure transmitters (including level and flow transmitters). (author)
Reimer, Paula J.; Bard, Edouard; Bayliss, Alex; Beck, J. Warren; Blackwell, Paul G.; Ramsey, Christopher Bronk; Brown, David M.; Buck, Caitlin E.; Edwards, R. Lawrence; Friedrich, Michael; Grootes, Pieter M.; Guilderson, Thomas P.; Haflidason, Haflidi; Hajdas, Irka; Hatte, Christine; Heaton, Timothy J.; Hogg, Alan G.; Hughen, Konrad A.; Kaiser, K. Felix; Kromer, Bernd; Manning, Sturt W.; Reimer, Ron W.; Richards, David A.; Scott, E. Marian; Southon, John R.; Turney, Christian S. M.; van der Plicht, Johannes
High-quality data from appropriate archives are needed for the continuing improvement of radiocarbon calibration curves. We discuss here the basic assumptions behind C-14 dating that necessitate calibration and the relative strengths and weaknesses of archives from which calibration data are
The LOFAR long baseline snapshot calibrator survey
Moldón, J.; et al., [Unknown; Carbone, D.; Markoff, S.; Wise, M.W.
Aims. An efficient means of locating calibrator sources for international LOw Frequency ARray (LOFAR) is developed and used to determine the average density of usable calibrator sources on the sky for subarcsecond observations at 140 MHz. Methods. We used the multi-beaming capability of LOFAR to
The LOFAR ling baseline snapshot calibrator survey
Moldon, J.; Deller, A.T.; Wucknitz, O.; Jackson, N.; Drabent, A.; Carozzi, T.; Conway, J.; Bentum, Marinus Jan; Bernardi, G.; Best, P.; Gunst, A.W.
Aims: An efficient means of locating calibrator sources for international LOw Frequency ARray (LOFAR) is developed and used to determine the average density of usable calibrator sources on the sky for subarcsecond observations at 140 MHz. Methods We used the multi-beaming capability of LOFAR to
The LOFAR long baseline snapshot calibrator survey
Moldón, J.; Deller, A. T.; Wucknitz, O.; Jackson, N.; Drabent, A.; Carozzi, T.; Conway, J.; Kapińska, A. D.; McKean, J. P.; Morabito, L.; Varenius, E.; Zarka, P.; Anderson, J.; Asgekar, A.; Avruch, I. M.; Bell, M. E.; Bentum, M. J.; Bernardi, G.; Best, P.; Bîrzan, L.; Bregman, J.; Breitling, F.; Broderick, J. W.; Brüggen, M.; Butcher, H. R.; Carbone, D.; Ciardi, B.; de Gasperin, F.; de Geus, E.; Duscha, S.; Eislöffel, J.; Engels, D.; Falcke, H.; Fallows, R. A.; Fender, R.; Ferrari, C.; Frieswijk, W.; Garrett, M. A.; Grießmeier, J.; Gunst, A. W.; Hamaker, J. P.; Hassall, T. E.; Heald, G.; Hoeft, M.; Juette, E.; Karastergiou, A.; Kondratiev, V. I.; Kramer, M.; Kuniyoshi, M.; Kuper, G.; Maat, P.; Mann, G.; Markoff, S.; McFadden, R.; McKay-Bukowski, D.; Morganti, R.; Munk, H.; Norden, M. J.; Offringa, A. R.; Orru, E.; Paas, H.; Pandey-Pommier, M.; Pizzo, R.; Polatidis, A. G.; Reich, W.; Röttgering, H.; Rowlinson, A.; Scaife, A. M. M.; Schwarz, D.; Sluman, J.; Smirnov, O.; Stappers, B. W.; Steinmetz, M.; Tagger, M.; Tang, Y.; Tasse, C.; Thoudam, S.; Toribio, M. C.; Vermeulen, R.; Vocks, C.; van Weeren, R. J.; White, S.; Wise, M. W.; Yatawatta, S.; Zensus, A.
Aims: An efficient means of locating calibrator sources for international LOw Frequency ARray (LOFAR) is developed and used to determine the average density of usable calibrator sources on the sky for subarcsecond observations at 140 MHz. Methods: We used the multi-beaming capability of LOFAR to
The ENEA calibration service for ionising radiations
International Nuclear Information System (INIS)
Monteventi, F.; Sermenghi, I.
The report describes all the facilities available at the the service of the ENEA Calibration Service for Ionising Radiations at Bologna (Italy). It gives a detailed description of all equipments qualified for photon fields metrology including the secondary standards and the calibration procedures performed for radiation monitoring devices and dosemeters [it
Providing primary standard calibrations beyond 20 MHz
International Nuclear Information System (INIS)
Bickley, C J; Zeqiri, B; Robinson, S P
The number of applications of medical ultrasound utilising frequencies in excess of 20 MHz has shown a consistent increase over recent years. Coupled with the commercial availability of wide-bandwidth hydrophones whose response extends beyond 40 MHz, this has driven a growing need to develop hydrophone calibration techniques at elevated frequencies. The current National Physical Laboratory primary standard method of calibrating hydrophones is based on an optical interferometer. This has been in operation for around 20 years and provides traceability over the frequency range of 0.3 to 20 MHz. More recently, calibrations carried out using the interferometer have been extended to 60 MHz, although the uncertainties associated with these calibrations are poor, being in excess of ±20% at high frequencies. Major contributions to the degraded calibration uncertainties arise from poor signal-to-noise at higher frequencies, the frequency response of the photodiodes used and the noise floor of the instrument. To improve the uncertainty of hydrophone calibrations above 20 MHz, it has been necessary to build and commission a new interferometer. Important features of the new primary standard are its use of a higher power laser to improve the signal-to-noise ratio, along with photodiodes whose greater bandwidth to improve the overall frequency response. This paper describes the design of key aspects of the new interferometer. It also presents some initial results of the performance assessment, including a detailed comparison of calibrations of NPL reference membrane hydrophones, undertaken using old and new interferometers for calibration up to 40 MHz
CryoSat SIRAL Calibration and Performance
Fornari, Marco; Scagliola, Michele; Tagliani, Nicolas; Parrinello, Tommaso
The main payload of CryoSat is a Ku band pulse-width limited radar altimeter, called SIRAL (Synthetic interferometric radar altimeter), that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. This allows to reach an along track resolution of about 250 meters which is a significant improvement over traditional pulse-width limited altimeters. Due to the fact that SIRAL is a phase coherent pulse-width limited radar altimeter, a proper calibration approach has been developed, including both an internal and external calibration. The internal calibration monitors the instrument impulse response and the transfer function, like traditional altimeters. In addition to that, the interferometer requires a special calibration developed ad hoc for SIRAL. The external calibration is performed with the use of a ground transponder, located in Svalbard, which receives SIRAL signal and sends the echo back to the satellite. Internal calibration data are processed on ground by the CryoSat Instrument Processing Facility (IPF1) and then applied to the science data. By April 2013, almost 3 years of calibration data will be available, which will be shown in this poster. The external calibration (transponder) data are processed and analyzed independently from the operational chain. The use of an external transponder has been very useful to determine instrument performance and for the tuning of the on-ground processor. This poster presents the transponder results in terms of range noise and datation error.
Planck 2013 results. V. LFI calibration
DEFF Research Database (Denmark)
Planck Collaboration,; Aghanim, N.; Armitage-Caplan, C.
We discuss the methods employed to photometrically calibrate the data acquired by the Low Frequency Instrument on Planck. Our calibration is based on the Solar Dipole, caused by motion of the Solar System with respect to the CMB rest frame, which provides a signal of a few mK with the same spectr...
Planck 2015 results: V. LFI calibration
DEFF Research Database (Denmark)
Ade, P. A R; Aghanim, N.; Ashdown, M.
We present a description of the pipeline used to calibrate the Planck Low Frequency Instrument (LFI) timelines into thermodynamic temperatures for the Planck 2015 data release, covering four years of uninterrupted operations. As in the 2013 data release, our calibrator is provided by the spin-syn...
Procedure for calibrating the Technicon Colorimeter I.
Black, J C; Furman, W B
We describe a rapid method for calibrating the Technicon AutoAnalyzer colorimeter I. Test solutions of bromphenol blue are recommended for the calibration, in preference to solutions of potassium dichromate, based on considerations of the instrument's working range and of the stray light characteristics of the associated filters.
Calibration of Geophone Micro-seismic Sensors
International Nuclear Information System (INIS)
Bowden, G.
This note describes a simple lab bench technique for calibrating the sensitivity and dynamics of the Mark Products L4C geophones used at SLAC for measuring microseismic ground motion and mechanical vibrations of accelerator support structures. Calibration results for SLAC's three L4C geophones are recorded
Calibration device for wide range monitor
International Nuclear Information System (INIS)
Kodoku, Masaya; Sato, Toshifumi.
The calibration device for a wide range monitor according to the present invention can continuously calibrate the entire counting regions of a wide range monitor. The wide range monitor detect the reactor power in the neutron source region by means of a pulse counting method and detects the reactor power in the intermediate region by means of a cambell method. A calibration signal outputting means is disposed for continuously outputting, as such calibration signals, pulse number varying signals in which the number of pulses per unit time varies depending on the reactor power in the neutron source region to be simulated and amplitude square means varying signal in which the mean square value of amplitude varies depending on the reactor power in the intermediate region to be simulated. By using both of the calibration signals, calibration can be conducted for the nuclear reactor power in the neutron source region and the intermediate region even if the calibration is made over two regions, further, calibration for the period present over the two region can be conducted easily as well. (I.S.)
Error-in-variables models in calibration
Lira, I.; Grientschnig, D.
In many calibration operations, the stimuli applied to the measuring system or instrument under test are derived from measurement standards whose values may be considered to be perfectly known. In that case, it is assumed that calibration uncertainty arises solely from inexact measurement of the responses, from imperfect control of the calibration process and from the possible inaccuracy of the calibration model. However, the premise that the stimuli are completely known is never strictly fulfilled and in some instances it may be grossly inadequate. Then, error-in-variables (EIV) regression models have to be employed. In metrology, these models have been approached mostly from the frequentist perspective. In contrast, not much guidance is available on their Bayesian analysis. In this paper, we first present a brief summary of the conventional statistical techniques that have been developed to deal with EIV models in calibration. We then proceed to discuss the alternative Bayesian framework under some simplifying assumptions. Through a detailed example about the calibration of an instrument for measuring flow rates, we provide advice on how the user of the calibration function should employ the latter framework for inferring the stimulus acting on the calibrated device when, in use, a certain response is measured.
Overview of hypersonic CFD code calibration studies
Miller, Charles G.
The topics are presented in viewgraph form and include the following: definitions of computational fluid dynamics (CFD) code validation; climate in hypersonics and LaRC when first 'designed' CFD code calibration studied was initiated; methodology from the experimentalist's perspective; hypersonic facilities; measurement techniques; and CFD code calibration studies.
Calibration of Ground -based Lidar instrument
DEFF Research Database (Denmark)
Villanueva, Héctor; Yordanova, Ginka
This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU's test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...
Lidar to lidar calibration phase 2
DEFF Research Database (Denmark)
Yordanova, Ginka; Courtney, Michael
This report presents the results from phase 2 of a lidar to lidar (L2L) calibration procedure. Phase two of the project included two measurement campaigns conducted at given sites. The purpose was to find out if the lidar-to-lidar calibration procedure can be conducted with similar results...
Radiation energy calibrating system and method
International Nuclear Information System (INIS)
Jacobson, A.F.
A radiation energy calibrating system and method which uses a pair of calibrated detectors for measurements of radiation intensity from x-ray tubes for a non-invasive determination of the electrical characteristics; I.E., the tube potential and/or current
Calibration method for ion mobility spectrometer
International Nuclear Information System (INIS)
Vasiliev, Valery
The new method for the calibration of the ion mobility spectrometer has been developed. This article describes the working principle, advantages and disadvantages of the calibration method operating in the mode of explosives detection. This method is most suitable for use in portable detectors, due to the small weight, small size parameters and low power consumption.
Calibration of Avent Wind IRIS SN 01030167
DEFF Research Database (Denmark)
Courtney, Michael
This report presents the result of the lidar calibration performed for a two-beam nacelle based lidar at DTU's test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement un...
Calibration of well-type ionization chambers
International Nuclear Information System (INIS)
Alves, C.F.E.; Leite, S.P.; Pires, E.J.; Magalhaes, L.A.G.; David, M.G.; Almeida, C.E. de
This paper presents the methodology developed by the Laboratorio de Ciencias Radiologicas and presently in use for determining of the calibration coefficient for well-type chambers used in the dosimetry of 192 Ir high dose rate sources. Uncertainty analysis involving the calibration procedure are discussed. (author)
Features calibration of the dynamic force transducers
Sc., M. Yu Prilepko D.; Lysenko, V. G.
The article discusses calibration methods of dynamic forces measuring instruments. The relevance of work is dictated by need to valid definition of the dynamic forces transducers metrological characteristics taking into account their intended application. The aim of this work is choice justification of calibration method, which provides the definition dynamic forces transducers metrological characteristics under simulation operating conditions for determining suitability for using in accordance with its purpose. The following tasks are solved: the mathematical model and the main measurements equation of calibration dynamic forces transducers by load weight, the main budget uncertainty components of calibration are defined. The new method of dynamic forces transducers calibration with use the reference converter "force-deformation" based on the calibrated elastic element and measurement of his deformation by a laser interferometer is offered. The mathematical model and the main measurements equation of the offered method is constructed. It is shown that use of calibration method based on measurements by the laser interferometer of calibrated elastic element deformations allows to exclude or to considerably reduce the uncertainty budget components inherent to method of load weight.
The long term stability of lidar calibrations
DEFF Research Database (Denmark)
Courtney, Michael; Gayle Nygaard, Nicolai
Wind lidars are now used extensively for wind resource measurements. One of the requirements for the data to be accepted in support of project financing (so-called 'banka-bility') is to demonstrate the long-term stability of lidar cali-brations. Calibration results for six Leosphere WindCube li...
Self-Calibration of CMB Polarimeters
Keating, Brian
Precision measurements of the polarization of the cosmic microwave background (CMB) radiation, especially experiments seeking to detect the odd-parity "B-modes", have far-reaching implications for cosmology. To detect the B-modes generated during inflation the flux response and polarization angle of these experiments must be calibrated to exquisite precision. While suitable flux calibration sources abound, polarization angle calibrators are deficient in many respects. Man-made polarized sources are often not located in the antenna's far-field, have spectral properties that are radically different from the CMB's, are cumbersome to implement and may be inherently unstable over the (long) duration these searches require to detect the faint signature of the inflationary epoch. Astrophysical sources suffer from time, frequency and spatial variability, are not visible from all CMB observatories, and none are understood with sufficient accuracy to calibrate future CMB polarimeters seeking to probe inflationary energy scales of ~1000 TeV. CMB TB and EB modes, expected to identically vanish in the standard cosmological model, can be used to calibrate CMB polarimeters. By enforcing the observed EB and TB power spectra to be consistent with zero, CMB polarimeters can be calibrated to levels not possible with man-made or astrophysical sources. All of this can be accomplished without any loss of observing time using a calibration source which is spectrally identical to the CMB B-modes. The calibration procedure outlined here can be used for any CMB polarimeter.
Nuclear radiation moisture gauge calibration standard
International Nuclear Information System (INIS)
Berry, R.L.
A hydrophobic standard for calibrating radiation moisture gauges is described. This standard has little or no affinity for water and accordingly will not take up or give off water under ambient conditions of fluctuating humidity in such a manner as to change the hydrogen content presented to a nuclear gauge undergoing calibration. (O.T.)
A statistical approach to instrument calibration
Robert R. Ziemer; David Strauss
Summary - It has been found that two instruments will yield different numerical values when used to measure identical points. A statistical approach is presented that can be used to approximate the error associated with the calibration of instruments. Included are standard statistical tests that can be used to determine if a number of successive calibrations of the...
Calibration and comparison of the NASA Lewis free-piston Stirling engine model predictions with RE-1000 test data
Geng, Steven M.
A free-piston Stirling engine performance code is being upgraded and validated at the NASA Lewis Research Center under an interagency agreement between the Department of Energy's Oak Ridge National Laboratory and NASA Lewis. Many modifications were made to the free-piston code in an attempt to decrease the calibration effort. A procedure was developed that made the code calibration process more systematic. Engine-specific calibration parameters are often used to bring predictions and experimental data into better agreement. The code was calibrated to a matrix of six experimental data points. Predictions of the calibrated free-piston code are compared with RE-1000 free-piston Stirling engine sensitivity test data taken at NASA Lewis. Resonable agreement was obtained between the code predictions and the experimental data over a wide range of engine operating conditions.
Comparison of calibration strategies for optical 3D scanners based on structured light projection using a new evaluation methodology
Bräuer-Burchardt, Christian; Ölsner, Sandy; Kühmstedt, Peter; Notni, Gunther
In this paper a new evaluation strategy for optical 3D scanners based on structured light projection is introduced. It can be used for the characterization of the expected measurement accuracy. Compared to the procedure proposed in the VDI/VDE guidelines for optical 3D measurement systems based on area scanning it requires less effort and provides more impartiality. The methodology is suitable for the evaluation of sets of calibration parameters, which mainly determine the quality of the measurement result. It was applied to several calibrations of a mobile stereo camera based optical 3D scanner. The performed calibrations followed different strategies regarding calibration bodies and arrangement of the observed scene. The results obtained by the different calibration strategies are discussed and suggestions concerning future work on this area are given.
Accounting for sensor calibration, data validation, measurement and sampling uncertainties in monitoring urban drainage systems.
Bertrand-Krajewski, J L; Bardin, J P; Mourad, M; Béranger, Y
Assessing the functioning and the performance of urban drainage systems on both rainfall event and yearly time scales is usually based on online measurements of flow rates and on samples of influent effluent for some rainfall events per year. In order to draw pertinent scientific and operational conclusions from the measurement results, it is absolutely necessary to use appropriate methods and techniques in order to i) calibrate sensors and analytical methods, ii) validate raw data, iii) evaluate measurement uncertainties, iv) evaluate the number of rainfall events to sample per year in order to determine performance indicator with a given uncertainty. Based an previous work, the paper gives a synthetic review of required and techniques, and illustrates their application to storage and settling tanks. Experiments show that, controlled and careful experimental conditions, relative uncertainties are about 20% for flow rates in sewer pipes, 6-10% for volumes, 25-35% for TSS concentrations and loads, and 18-276% for TSS removal rates. In order to evaluate the annual pollutant interception efficiency of storage and settling tanks with a given uncertainty, efforts should first be devoted to decrease the sampling uncertainty by increasing the number of sampled events.
NIST high-dose calibration services
International Nuclear Information System (INIS)
Humphreys, J.C.
There is a need for the standardization of high-dose measurements used in the radiation-processing industry in order to provide assured traceability to national standards. NIST provides dosimetry calibration services to this industry. One of these services involves administration of known absorbed doses of gamma rays to customer-supplied dosimeters. The dosimeters are packaged to provide electron equilibrium conditions and are irradiated in a standard 60 Co calibration facility; this provides a calibration of that batch of dosimeters. Another service consists of supplying to a customer calibrated transfer dosimeters for irradiation with the customer's radiation source. The irradiated transfer dosimeters are then returned to NIST for analysis; the results are reported to the customer, providing a calibration of the dose rate of the customer's source. (orig.)
Calibration-free optical chemical sensors
DeGrandpre, Michael D.
An apparatus and method for taking absorbance-based chemical measurements are described. In a specific embodiment, an indicator-based pCO2 (partial pressure of CO2) sensor displays sensor-to-sensor reproducibility and measurement stability. These qualities are achieved by: 1) renewing the sensing solution, 2) allowing the sensing solution to reach equilibrium with the analyte, and 3) calculating the response from a ratio of the indicator solution absorbances which are determined relative to a blank solution. Careful solution preparation, wavelength calibration, and stray light rejection also contribute to this calibration-free system. Three pCO2 sensors were calibrated and each had response curves which were essentially identical within the uncertainty of the calibration. Long-term laboratory and field studies showed the response had no drift over extended periods (months). The theoretical response, determined from thermodynamic characterization of the indicator solution, also predicted the observed calibration-free performance.
Calibration biases in logical reasoning tasks
Directory of Open Access Journals (Sweden)
Guillermo Macbeth
Full Text Available The aim of this contribution is to present an experimental study about calibration in deductive reasoning tasks. Calibration is defi ned as the empirical convergence or divergence between the objective and the subjective success. The underconfi dence bias is understood as the dominance of the former over the latter. The hypothesis of this study states that the form of the propositions presented in the experiment is critical for calibration phenomena. Affi rmative and negative propositions are distinguished in their cognitive processing. Results suggests that monotonous compound propositions are prone to underconfi dence. An heuristic approach to this phenomenon is proposed. The activation of a monotony heuristic would produce an illusion of simplicity that generates the calibration bias. These evidence is analysed in the context of the metacognitive modeling of calibration phenomena.
Systems and methods of eye tracking calibration
DEFF Research Database (Denmark)
Methods and systems to facilitate eye tracking control calibration are provided. One or more objects are displayed on a display of a device, where the one or more objects are associated with a function unrelated to a calculation of one or more calibration parameters. The one or more calibration...... parameters relate to a calibration of a calculation of gaze information of a user of the device, where the gaze information indicates where the user is looking. While the one or more objects are displayed, eye movement information associated with the user is determined, which indicates eye movement of one...... or more eye features associated with at least one eye of the user. The eye movement information is associated with a first object location of the one or more objects. The one or more calibration parameters are calculated based on the first object location being associated with the eye movement information....
Electromagnetic Calorimeter Calibration with $\\pi^{0}$
Puig Navarro, A
Several methods can be used in order to achieve precise calibration of the LHCb Electromagnetic Calorimeter (ECAL) once reasonable cell equalization has been reached. At low transverse energy, the standard calibration procedure is an iterative method based on the fit of the $\\gamma\\gamma$ invariant mass distribution for each cell of the decay $\\pi^{0}\\to\\gamma\\gamma$ with resolved photons. A new technique for generating the combinatorial background of such decays directly from data has been developed. Knowledge of the background could allow an alternative calibration method based on a event by event fit of the same $\\gamma\\gamma$ invariant mass distribution where contributions from groups of cells are considered in a single fit. The background generation procedure and this possible new calibration method are presented in this poster, in addition to an overview of the LHCb Calorimetry system and ECAL calibration techniques.
Cryogenic Thermometer Calibration Facility at CERN
Balle, C; Thermeau, J P
A cryogenic thermometer calibration facility has been designed and is being commissioned in preparation for the very stringent requirements on the temperature control of the LHC superconducting magnets. The temperature is traceable in the 1.5 to 30 K range to standards maintained in a national metrological laboratory by using a set of Rhodium-Iron temperature sensors of metrological quality. The calibration facility is designed for calibrating simultaneously 60 industrial cryogenic thermometers in the 1.5 K to 300 K temperature range, a thermometer being a device that includes both a temperature sensor and the wires heat-intercept. The thermometers can be calibrated in good and degraded vacuum or immersed in the surrounding fluid and at different Joule self-heating conditions that match those imposed by signal conditioners used in large cryogenic machinery. The calibration facility can be operated in an automatic mode and all the control and safety routines are handled by a Programmable Logic Controller (PLC)...
Energy calibration of a multilayer photon detector
International Nuclear Information System (INIS)
Johnson, R.A.
The job of energy calibration was broken into three parts: gain normalization of all equivalent elements; determination of the functions for conversion of pulse height to energy; and gain stabilization. It is found that calorimeter experiments are no better than their calibration systems - calibration errors will be the major source of error at high energies. Redundance is found to be necessary - the system should be designed such that every element could be replaced during the life of the experiment. It is found to be important to have enough data taken during calibration runs and during the experiment to be able to sort out where the calibration problems were after the experiment is over. Each layer was normalized independently with electrons, and then the pulse height to energy conversion was determined with photons. The primary method of gain stabilization used the light flasher system
The ATLAS Electromagnetic Calorimeter Calibration Workshop
Hong Ma; Isabelle Wingerter
The ATLAS Electromagnetic Calorimeter Calibration Workshop took place at LAPP-Annecy from the 1st to the 3rd of October; 45 people attended the workshop. A detailed program was setup before the workshop. The agenda was organised around very focused presentations where questions were raised to allow arguments to be exchanged and answers to be proposed. The main topics were: Electronics calibration Handling of problematic channels Cluster level corrections for electrons and photons Absolute energy scale Streams for calibration samples Calibration constants processing Learning from commissioning Forty-five people attended the workshop. The workshop was on the whole lively and fruitful. Based on years of experience with test beam analysis and Monte Carlo simulation, and the recent operation of the detector in the commissioning, the methods to calibrate the electromagnetic calorimeter are well known. Some of the procedures are being exercised in the commisssioning, which have demonstrated the c...
CERN Radiation Protection (RP) calibration facilities
AUTHOR|(CDS)2082069; Macián-Juan, Rafael
Radiation protection calibration facilities are essential to ensure the correct operation of radiation protection instrumentation. Calibrations are performed in specific radiation fields according to the type of instrument to be calibrated: neutrons, photons, X-rays, beta and alpha particles. Some of the instruments are also tested in mixed radiation fields as often encountered close to high-energy particle accelerators. Moreover, calibration facilities are of great importance to evaluate the performance of prototype detectors; testing and measuring the response of a prototype detector to well-known and -characterized radiation fields contributes to improving and optimizing its design and capabilities. The CERN Radiation Protection group is in charge of performing the regular calibrations of all CERN radiation protection devices; these include operational and passive dosimeters, neutron and photon survey-meters, and fixed radiation detectors to monitor the ambient dose equivalent, H*(10), inside CERN accelera...
Bayesian calibration : past achievements and future challenges
International Nuclear Information System (INIS)
Christen, J.A.
Due to variations of the radiocarbon content in the biosphere over time, radiocarbon determinations need to be calibrated to obtain calendar years. Over the past decade a series of researchers have investigated the possibility of using Bayesian statistics to calibrate radiocarbon determinations, the main feature being the inclusion of contextual information into the calibration process. This allows for a coherent calibration of groups of determinations arising from related contexts (stratigraphical layers, peat cores, cultural events, ect.). Moreover, the 'related contexts' are also dated, and not only the material radiocarbon dated itself. We review Bayesian Calibration and state some of its current challenges like: software development, prior specification, robustness, etc. (author). 14 refs., 4 figs
Direct illumination LED calibration for telescope photometry
International Nuclear Information System (INIS)
Barrelet, E.; Juramy, C.
A calibration method for telescope photometry, based on the direct illumination of a telescope with a calibrated light source regrouping multiple LEDs, is proposed. Its purpose is to calibrate the instrument response. The main emphasis of the proposed method is the traceability of the calibration process and a continuous monitoring of the instrument in order to maintain a 0.2% accuracy over a period of years. Its specificity is to map finely the response of the telescope and its camera as a function of all light ray parameters. This feature is essential to implement a computer model of the instrument representing the variation of the overall light collection efficiency of each pixel for various filter configurations. We report on hardware developments done for SNDICE, the first application of this direct illumination calibration system which will be installed in Canada France Hawaii telescope (CFHT) for its leading supernova experiment (SNLS)
On-line monitoring for calibration reduction
International Nuclear Information System (INIS)
Hoffmann, M.
On-Line Monitoring evaluates instrument channel performance by assessing its consistency with other plant indications. Elimination or reduction of unnecessary field calibrations can reduce associated labour costs, reduce personnel radiation exposure, and reduce the potential for calibration errors. On-line calibration monitoring is an important technique to implement a state-based maintenance approach and reduce unnecessary field calibrations. In this report we will look at how the concept is currently applied in the industry and what the arising needs are as it becomes more commonplace. We will also look at the PEANO System, a tool developed by the Halden Project to perform signal validation and on-line calibration monitoring. Some issues will be identified that are being addressed in the further development of these tools to better serve the future needs of the industry in this area. An outline for how to improve these points and which aspects should be taken into account is described in detail. (Author)
Systematic calibration of an integrated x-ray and optical tomography system for preclinical radiation research
Energy Technology Data Exchange (ETDEWEB)
Yang, Yidong, E-mail: email@example.com [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 and Department of Radiation Oncology, University of Miami School of Medicine, Miami, Florida 33136 (United States); Wang, Ken Kang-Hsin; Wong, John W. [Department of Radiation Oncology and Molecular Radiation Sciences, Johns Hopkins University School of Medicine, Baltimore, Maryland 21231 (United States); Eslami, Sohrab; Iordachita, Iulian I. [Laboratory for Computational Sensing and Robotics, Johns Hopkins University, Baltimore, Maryland 21218 (United States); Patterson, Michael S. [Juravinski Cancer Centre and Department of Medical Physics and Applied Radiation Sciences, McMaster University, Hamilton, Ontario L8S4K1 (Canada)
Purpose: The cone beam computed tomography (CBCT) guided small animal radiation research platform (SARRP) has been developed for focal tumor irradiation, allowing laboratory researchers to test basic biological hypotheses that can modify radiotherapy outcomes in ways that were not feasible previously. CBCT provides excellent bone to soft tissue contrast, but is incapable of differentiating tumors from surrounding soft tissue. Bioluminescence tomography (BLT), in contrast, allows direct visualization of even subpalpable tumors and quantitative evaluation of tumor response. Integration of BLT with CBCT offers complementary image information, with CBCT delineating anatomic structures and BLT differentiating luminescent tumors. This study is to develop a systematic method to calibrate an integrated CBCT and BLT imaging system which can be adopted onboard the SARRP to guide focal tumor irradiation. Methods: The integrated imaging system consists of CBCT, diffuse optical tomography (DOT), and BLT. The anatomy acquired from CBCT and optical properties acquired from DOT serve as a priori information for the subsequent BLT reconstruction. Phantoms were designed and procedures were developed to calibrate the CBCT, DOT/BLT, and the entire integrated system. Geometrical calibration was performed to calibrate the CBCT system. Flat field correction was performed to correct the nonuniform response of the optical imaging system. Absolute emittance calibration was performed to convert the camera readout to the emittance at the phantom or animal surface, which enabled the direct reconstruction of the bioluminescence source strength. Phantom and mouse imaging were performed to validate the calibration. Results: All calibration procedures were successfully performed. Both CBCT of a thin wire and a euthanized mouse revealed no spatial artifact, validating the accuracy of the CBCT calibration. The absolute emittance calibration was validated with a 650 nm laser source, resulting in a 3
Systematic calibration of an integrated x-ray and optical tomography system for preclinical radiation research
International Nuclear Information System (INIS)
Yang, Yidong; Wang, Ken Kang-Hsin; Wong, John W.; Eslami, Sohrab; Iordachita, Iulian I.; Patterson, Michael S.
Purpose: The cone beam computed tomography (CBCT) guided small animal radiation research platform (SARRP) has been developed for focal tumor irradiation, allowing laboratory researchers to test basic biological hypotheses that can modify radiotherapy outcomes in ways that were not feasible previously. CBCT provides excellent bone to soft tissue contrast, but is incapable of differentiating tumors from surrounding soft tissue. Bioluminescence tomography (BLT), in contrast, allows direct visualization of even subpalpable tumors and quantitative evaluation of tumor response. Integration of BLT with CBCT offers complementary image information, with CBCT delineating anatomic structures and BLT differentiating luminescent tumors. This study is to develop a systematic method to calibrate an integrated CBCT and BLT imaging system which can be adopted onboard the SARRP to guide focal tumor irradiation. Methods: The integrated imaging system consists of CBCT, diffuse optical tomography (DOT), and BLT. The anatomy acquired from CBCT and optical properties acquired from DOT serve as a priori information for the subsequent BLT reconstruction. Phantoms were designed and procedures were developed to calibrate the CBCT, DOT/BLT, and the entire integrated system. Geometrical calibration was performed to calibrate the CBCT system. Flat field correction was performed to correct the nonuniform response of the optical imaging system. Absolute emittance calibration was performed to convert the camera readout to the emittance at the phantom or animal surface, which enabled the direct reconstruction of the bioluminescence source strength. Phantom and mouse imaging were performed to validate the calibration. Results: All calibration procedures were successfully performed. Both CBCT of a thin wire and a euthanized mouse revealed no spatial artifact, validating the accuracy of the CBCT calibration. The absolute emittance calibration was validated with a 650 nm laser source, resulting in a 3
Directory of Open Access Journals (Sweden)
J. Hieronymus
Full Text Available Methods for geometric calibration of cameras in close-range photogrammetry are established and well investigated. The most common one is based on test-fields with well-known pattern, which are observed from different directions. The parameters of a distortion model are calculated using bundle-block-adjustment-algorithms. This methods works well for short focal lengths, but is essentially more problematic to use with large focal lengths. Those would require very large test-fields and surrounding space. To overcome this problem, there is another common method for calibration used in remote sensing. It employs measurements using collimator and a goniometer. A third calibration method uses diffractive optical elements (DOE to project holograms of well known pattern. In this paper these three calibration methods are compared empirically, especially in terms of accuracy. A camera has been calibrated with those methods mentioned above. All methods provide a set of distortion correction parameters as used by the photogrammetric software Australis. The resulting parameter values are very similar for all investigated methods. The three sets of distortion parameters are crosscompared against all three calibration methods. This is achieved by inserting the gained distortion parameters as fixed input into the calibration algorithms and only adjusting the exterior orientation. The RMS (root mean square of the remaining image coordinate residuals are taken as a measure of distortion correction quality. There are differences resulting from the different calibration methods. Nevertheless the measure is small for every comparison, which means that all three calibration methods can be used for accurate geometric calibration.
Guidelines on calibration of neutron measuring devices
International Nuclear Information System (INIS)
Burger, G.
The International Atomic Energy Agency and the World Health Organization have agreed to establish an IAEA/WHO Network of Secondary Standard Dosimetry Laboratories (SSDLs) in order to improve accuracy in applied radiation dosimetry throughout the world. These SSDLs must be equipped with, and maintain, secondary standard instruments, which have been calibrated against primary standards, and must be nominated by their governments for membership of the network. The majority of the existing SSDLs were established primarily to work with photon radiation (X-rays and gamma rays). Neutron sources are, however, increasingly being applied in industrial processes, research, nuclear power development and radiation biology and medicine. Thus, it is desirable that the SSDLs in countries using neutron sources on a regular basis should also fulfil the minimum requirements to calibrate neutron measuring devices. It is the primary purpose of this handbook to provide guidance on calibration of instruments for radiation protection. A calibration laboratory should also be in a position to calibrate instrumentation being used for the measurement of kerma and absorbed dose and their corresponding rates. This calibration is generally done with photons. In addition, since each neutron field is usually contaminated by photons produced in the source or by scatter in the surrounding media, neutron protection instrumentation has to be tested with respect to its intrinsic photon response. The laboratory will therefore need to possess equipment for photon calibration. This publication deals primarily with methods of applying radioactive neutron sources for calibration of instrumentation, and gives an indication of the space, manpower and facilities needed to fulfil the minimum requirements of a calibration laboratory for neutron work. It is intended to serve as a guide for centres about to start on neutron dosimetry standardization and calibration. 94 refs, 8 figs, 12 tabs
Fabrication and calibration of FORTIS
Fleming, Brian T.; McCandliss, Stephan R.; Kaiser, Mary Elizabeth; Kruk, Jeffery; Feldman, Paul D.; Kutyrev, Alexander S.; Li, Mary J.; Rapchun, David A.; Lyness, Eric; Moseley, S. H.; Siegmund, Oswald; Vallerga, John; Martin, Adrian
The Johns Hopkins University sounding rocket group is entering the final fabrication phase of the Far-ultraviolet Off Rowland-circle Telescope for Imaging and Spectroscopy (FORTIS); a sounding rocket borne multi-object spectro-telescope designed to provide spectral coverage of 43 separate targets in the 900 - 1800 Angstrom bandpass over a 30' x 30' field-of- view. Using "on-the-fly" target acquisition and spectral multiplexing enabled by a GSFC microshutter array, FORTIS will be capable of observing the brightest regions in the far-UV of nearby low redshift (z ~ 0.002 - 0.02) star forming galaxies to search for Lyman alpha escape, and to measure the local gas-to-dust ratio. A large area (~ 45 mm x 170 mm) microchannel plate detector built by Sensor Sciences provides an imaging channel for targeting flanked by two redundant spectral outrigger channels. The grating is ruled directly onto the secondary mirror to increase efficiency. In this paper, we discuss the recent progress made in the development and fabrication of FORTIS, as well as the results of early calibration and characterization of our hardware, including mirror/grating measurements, detector performance, and early operational tests of the microshutter arrays.
A cryogenic infrared calibration target
Wollack, E. J.; Kinzer, R. E.; Rinehart, S. A.
A compact cryogenic calibration target is presented that has a peak diffuse reflectance, R ⩽ 0.003, from 800 to 4800 cm-1 (12 - 2 μm). Upon expanding the spectral range under consideration to 400-10 000 cm-1 (25 - 1 μm) the observed performance gracefully degrades to R ⩽ 0.02 at the band edges. In the implementation described, a high-thermal-conductivity metallic substrate is textured with a pyramidal tiling and subsequently coated with a thin lossy dielectric coating that enables high absorption and thermal uniformity across the target. The resulting target assembly is lightweight, has a low-geometric profile, and has survived repeated thermal cycling from room temperature to ˜4 K. Basic design considerations, governing equations, and test data for realizing the structure described are provided. The optical properties of selected absorptive materials—Acktar Fractal Black, Aeroglaze Z306, and Stycast 2850 FT epoxy loaded with stainless steel powder—are characterized and presented.
In-situ Eh sensor measurement and calibration: application to seafloor observatories
Ding, K.; Seyfried, W. E.; Tan, C.
Eh measurement is often used with manned submersible and AUV assets as an effective way to detect and locate seafloor hydrothermal activity. Eh can be fundamentally and sensitively linked to dissolved H 2 , which, in turn, serves as a key constraint on subseafloor redox reactions. Moreover, Eh is now being increasingly relied on for event detection and process monitoring efforts intrinsic to cabled seafloor observatories. Due to seawater interaction with electrochemical components fundamental to the operation of the Eh sensor, however, the quality and reliability of the measurements are often compromised by signal drift, especially when the sensor is used for long term deployment. To solve this problem, a calibration protocol was developed and added to our previously constructed pH 'calibrator'. Thus, the integrated electrochemical system now permits the combined in-situ measurement and calibration of pH and Eh of seafloor hydrothermal fluids. Key aspects of the design for this calibration system are: (1) the sensing electrodes can be kept preserved in fluid of known pH, Eh and NaCl concentration prior to use, thereby preventing deterioration of electrode response characteristics by chemical and biological activity; (2) the system consists of valves and pumps for flow control, and therefore can be operated remotely with power from the seafloor cabled observatory, or as a stand-alone device, using battery power for shorter-term deployments. In both cases, standardization with on-board fluids of known redox, pH, and NaCl activity can be activated at any time, providing enhanced reliability (3) the current development is aimed at deep sea environments, cold seeps, and hydrothermal diffuse flow fluids at the temperatures up to 100°C and depths up to 4500 m. The in-situ operation is especially well-suited for use with cabled observatory for real time intervention and event response owing to enabled power supply and two way communications. Field tests have been
Automation of dosimeters calibration for radiotherapy in secondary dosimetric calibration laboratory of the CPHR
International Nuclear Information System (INIS)
Acosta, Andy L. Romero; Lores, Stefan Gutierrez
This paper presents the design and implementation of an automated system for measurements in the calibration of reference radiation dosimeters. It was made a software application that performs the acquisition of the measured values of electric charge, calculated calibration coefficient and automates the calibration certificate issuance. These values are stored in a log file on a PC. The use of the application improves control over the calibration process, helps to humanize the work and reduces personnel exposure. The tool developed has been applied to the calibration of dosimeters radiation patterns in the LSCD of the Centro de Proteccion e Higiene de las Radiaciones, Cuba
Seepage Calibration Model and Seepage Testing Data
Energy Technology Data Exchange (ETDEWEB)
S. Finsterle
-Drift to obtain the permeability structure for the seepage model; (3) to use inverse modeling to calibrate the SCM and to estimate seepage-relevant, model-related parameters on the drift scale; (4) to estimate the epistemic uncertainty of the derived parameters, based on the goodness-of-fit to the observed data and the sensitivity of calculated seepage with respect to the parameters of interest; (5) to characterize the aleatory uncertainty of the parameters as a result of spatial variability; (6) to evaluate prediction uncertainty based on linear uncertainty-propagation analyses and Monte Carlo simulations; (7) to validate the SCM during model development, and validate the SCM using the post-development activities outlined in the Technical Work Plan (TWP); (8) to provide the technical basis for the resolution of unconfirmed issues previously labeled ''to be verified'' (TBV); and (9) to provide the technical basis for screening of certain seepage-related features, events, and processes (FEPs).
Seepage Calibration Model and Seepage Testing Data
International Nuclear Information System (INIS)
Finsterle, S.
; (3) to use inverse modeling to calibrate the SCM and to estimate seepage-relevant, model-related parameters on the drift scale; (4) to estimate the epistemic uncertainty of the derived parameters, based on the goodness-of-fit to the observed data and the sensitivity of calculated seepage with respect to the parameters of interest; (5) to characterize the aleatory uncertainty of the parameters as a result of spatial variability; (6) to evaluate prediction uncertainty based on linear uncertainty-propagation analyses and Monte Carlo simulations; (7) to validate the SCM during model development, and validate the SCM using the post-development activities outlined in the Technical Work Plan (TWP); (8) to provide the technical basis for the resolution of unconfirmed issues previously labeled ''to be verified'' (TBV); and (9) to provide the technical basis for screening of certain seepage-related features, events, and processes (FEPs)
Hiding effort to gain a competitive advantage: Evidence from China.
Zhao, Li; Heyman, Gail D
Previous studies with Western populations have shown that adolescents' tendency to downplay their academic effort is affected by two kinds of motives: ability-related motives (e.g., to appear competent) and social approval motives (e.g., to be popular). In this research, we test for the presence of additional competition-related motives in China, a culture placing strong emphasis on academic competition. Study 1 (N = 150) showed that, in response to a scenario in which a hard-working high-school junior hid effort from classmates, the most highly endorsed explanation was "to influence others to work less hard to maintain a competitive advantage." Study 2 (N = 174) revealed that competition-related explanations were endorsed relatively more often when the speaker and audience had similar academic rankings. This tendency was most evident when both speaker and audience were top performers, and when this was the case, participants' desire to demonstrate superiority over others was a positive predictor of endorsement of competition-related motives. Study 3 (N = 137) verified that competition-related motives were more strongly endorsed among Chinese participants than U.S. These results suggest that at least in cultures that emphasize academic competition and in contexts where competition is salient, hiding effort is often about attempting to gain strategic advantage. © 2016 International Union of Psychological Science.
Comparative assessment of world research efforts on magnetic confinement fusion
International Nuclear Information System (INIS)
McKenney, B.L.; McGrain, M.; Rutherford, P.H.
This report presents a comparative assessment of the world's four major research efforts on magnetic confinement fusion, including a comparison of the capabilities in the Soviet Union, the European Community (Western Europe), Japan, and the United States. A comparative evaluation is provided in six areas: tokamak confinement; alternate confinement approaches; plasma technology and engineering; and fusion computations. The panel members are involved actively in fusion-related research, and have extensive experience in previous assessments and reviews of the world's four major fusion programs. Although the world's four major fusion efforts are roughly comparable in overall capabilities, two conclusions of this report are inescapable. First, the Soviet fusion effort is presently the weakest of the four programs in most areas of the assessment. Second, if present trends continue, the United States, once unambiguously the world leader in fusion research, will soon lose its position of leadership to the West European and Japanese fusion programs. Indeed, before the middle 1990s, the upgraded large-tokamak facilities, JT-60U (Japan) and JET (Western Europe), are likely to explore plasma conditions and operating regimes well beyond the capabilities of the TFTR tokamak (United States). In addition, if present trends continue in the areas of fusion nuclear technology and materials, and plasma technology and materials, and plasma technology development, the capabilities of Japan and Western Europe in these areas (both with regard to test facilities and fusion-specific industrial capabilities) will surpass those of the United States by a substantial margin before the middle 1990s
Reduced Delay of Gratification and Effortful Control among Young Children with Autism Spectrum Disorders
Faja, Susan; Dawson, Geraldine
We explored internal control of behavior using direct observation and parent report. Previous research has found that both the delay of gratification task and parent-reported effortful control predict later social ability and more positive outcomes in typically developing children. Children with autism spectrum disorder have previously been…
Student Effort, Consistency and Online Performance
Directory of Open Access Journals (Sweden)
Hilde Patron
Full Text Available This paper examines how student effort, consistency, motivation, and marginal learning, influence student grades in an online course. We use data from eleven Microeconomics courses taught online for a total of 212 students. Our findings show that consistency, or less time variation, is a statistically significant explanatory variable, whereas effort, or total minutes spent online, is not. Other independent variables include GPA and the difference between a pre-test and a post-test. The GPA is used as a measure of motivation, and the difference between a post-test and pre-test as marginal learning. As expected, the level of motivation is found statistically significant at a 99% confidence level, and marginal learning is also significant at a 95% level.
Summary of process research analysis efforts
Burger, D. R.
A summary of solar-cell process research analysis efforts was presented. Process design and cell design are interactive efforts where technology from integrated circuit processes and other processes are blended. The primary factors that control cell efficiency are: (1) the bulk parameters of the available sheet material, (2) the retention and enhancement of these bulk parameters, and (3) the cell design and the cost to produce versus the finished cells performance. The process sequences need to be tailored to be compatible with the sheet form, the cell shape form, and the processing equipment. New process options that require further evaluation and utilization are lasers, robotics, thermal pulse techniques, and new materials. There are numerous process control techniques that can be adapted and used that will improve product uniformity and reduced costs. Two factors that can lead to longer life modules are the use of solar cell diffusion barriers and improved encapsulation.
Non-proliferation efforts in South Asia
International Nuclear Information System (INIS)
Chellaney, B.
Southern Asia is one of the most volatile regions in the world because of inter-State and intra-State conflicts. Security in the region highly depends on the rival capabilities of the involved states, Pakistan, India, China. Increased Confidence building and nuclear transparency are becoming more significant issues in attaining stability in the region, although non-proliferation efforts in this region have attained little headway
Some recent efforts toward high density implosions
International Nuclear Information System (INIS)
McClellan, G.E.
Some recent Livermore efforts towards achieving high-density implosions are presented. The implosion dynamics necessary to compress DT fuel to 10 to 100 times liquid density are discussed. Methods of diagnosing the maximum DT density for a specific design are presented along with results to date. The dynamics of the double-shelled target with an exploding outer shell are described, and some preliminary experimental results are presented
Evaluative language, cognitive effort and attitude change.
van der Pligt, J.; van Schie, E.C.M.; Martijn, C.
Tested the hypotheses that evaluatively biased language influences attitudes and that the magnitude and persistence of attitude change depends on the amount of cognitive effort. 132 undergraduates participated in the experiment, which used material focusing on the issue of restricting adolescent driving over the weekends to reduce the number of fatal traffic accidents. Results indicate that evaluatively biased language can affect attitudes. Using words that evaluate the pro-position positivel...
Efforts to identify spore forming bacillus
Energy Technology Data Exchange (ETDEWEB)
Zuleiha, M.S.; Hilmy, N. (National Atomic Energy Agency, Jakarta (Indonesia). Pasar Djumat Research Centre)
Efforts to identify 47 species of radioresistant spore forming bacillus sp. isolated from locally produced medical devices have been carried out. The identifications was conducted using 19 kinds of biochemical tests and compared to species to bacillus subtilis W. T.; bacillus pumilus E 601 and bacillus sphaericus Csub(I)A. The results showed that bacillus sp. examined could be divided into 6 groups, i.e. bacillus cereus; bacillus subtilis; bacillus stearothermophylus; bacillus coagulans; bacillus sphaericus and bacillus circulans.
Efforts to identify spore forming bacillus
International Nuclear Information System (INIS)
Zuleiha, M.S.; Hilmy, Nazly
Efforts to identify 47 species of radioresistant spore forming bacillus sp. isolated from locally produced medical devices have been carried out. The identifications was conducted using 19 kinds of biochemical tests and compared to species to bacillus subtilis W. T.; bacillus pumilus E 601 and bacillus sphaericus Csub(I)A. The results showed that bacillus sp. examined could be divided into 6 groups, i.e. bacillus cereus; bacillus subtilis; bacillus stearothermophylus; bacillus coagulans; bacillus sphaericus and bacillus circulans. (author)
Environmental Determinants of Lexical Processing Effort
McDonald, Scott
Institute for Adaptive and Neural Computation A central concern of psycholinguistic research is explaining the relative ease or difficulty involved in processing words. In this thesis, we explore the connection between lexical processing effort and measurable properties of the linguistic environment. Distributional information (information about a word's contexts of use) is easily extracted from large language corpora in the form of co-occurrence statistics. We claim that su...
Duke Power's liquid radwaste processing improvement efforts
International Nuclear Information System (INIS)
Baker, R.E. Jr.; Bramblett, J.W.
The rising cost of processing liquid radwaste and industry efforts to reduce offsite isotopic contributions has drawn greater attention to the liquid radwaste area. Because of economic pressures to reduce cost and simultaneously improve performance, Duke Power has undertaken a wide ranging effort to cost effectively achieve improvements in the liquid radwaste processing area. Duke Power has achieved significant reductions over recent years in the release of curies to the environment from the Liquid Radwaste Treatmentt systems at its Catawba, McGuire, and Oconee stations. System wide site curie reductions of 78% have been achieved in a 3 year period. These curie reductions have been achieved while simultaneously reducing the amount of media used to accomplish treatment. The curie and media usage reductions have been achieved at low capital cost expenditures. A large number of approaches and projects have been used to achieve these curie and media usage reductions. This paper will describe the various projects and the associated results for Duke Power's processing improvement efforts. The subjects/projects which will be described include: (1) Cooperative philosophy between stations (2) Source Control (3) Processing Improvements (4) Technology Testing
SPRT Calibration Uncertainties and Internal Quality Control at a Commercial SPRT Calibration Facility
Wiandt, T. J.
The Hart Scientific Division of the Fluke Corporation operates two accredited standard platinum resistance thermometer (SPRT) calibration facilities, one at the Hart Scientific factory in Utah, USA, and the other at a service facility in Norwich, UK. The US facility is accredited through National Voluntary Laboratory Accreditation Program (NVLAP), and the UK facility is accredited through UKAS. Both provide SPRT calibrations using similar equipment and procedures, and at similar levels of uncertainty. These uncertainties are among the lowest available commercially. To achieve and maintain low uncertainties, it is required that the calibration procedures be thorough and optimized. However, to minimize customer downtime, it is also important that the instruments be calibrated in a timely manner and returned to the customer. Consequently, subjecting the instrument to repeated calibrations or extensive repeated measurements is not a viable approach. Additionally, these laboratories provide SPRT calibration services involving a wide variety of SPRT designs. These designs behave differently, yet predictably, when subjected to calibration measurements. To this end, an evaluation strategy involving both statistical process control and internal consistency measures is utilized to provide confidence in both the instrument calibration and the calibration process. This article describes the calibration facilities, procedure, uncertainty analysis, and internal quality assurance measures employed in the calibration of SPRTs. Data will be reviewed and generalities will be presented. Finally, challenges and considerations for future improvements will be discussed.
Intercomparison and calibration of dose calibrators used in nuclear medicine facilities
Costa, A M D
The aim of this work was to establish a working standard for intercomparison and calibration of dose calibrators used in most of nuclear medicine facilities for the determination of the activity of radionuclides administered to patients in specific examinations or therapeutic procedures. A commercial dose calibrator, a set of standard radioactive sources, and syringes, vials and ampoules with radionuclide solutions used in nuclear medicine were utilized in this work. The commercial dose calibrator was calibrated for radionuclide solutions used in nuclear medicine. Simple instrument tests, such as linearity response and variation response with the source volume at a constant source activity concentration were performed. This instrument may be used as a reference system for intercomparison and calibration of other activity meters, as a method of quality control of dose calibrators utilized in nuclear medicine facilities.
Calibration and intercomparison methods of dose calibrators used in nuclear medicine facilities
International Nuclear Information System (INIS)
Costa, Alessandro Martins da
Dose calibrators are used in most of the nuclear medicine facilities to determine the amount of radioactivity administered to a patient in a particular investigation or therapeutic procedure. It is therefore of vital importance that the equipment used presents good performance and is regular;y calibrated at a authorized laboratory. This occurs of adequate quality assurance procedures are carried out. Such quality control tests should be performed daily, other biannually or yearly, testing, for example, its accuracy and precision, the reproducibility and response linearity. In this work a commercial dose calibrator was calibrated with solution of radionuclides used in nuclear medicine. Simple instrument tests, such as response linearity and the response variation of the source volume increase at a constant source activity concentration, were performed. This instrument can now be used as a working standard for calibration of other dose calibrators/ An intercomparison procedure was proposed as a method of quality control of dose calibrators used in nuclear medicine facilities. (author)
International Nuclear Information System (INIS)
Galan Valera, M. P.; Acena Berrenechea, M. L.
A method for as certain the activity by alpha spectroscopy with semiconductor detectors, of a solution of 232U is presented. It consists of the comparison with a 233U solution activity previously measured in a gridded ionization chamber of 2π geometry. The total measurement uncertainty is about + - 0,02. (Author) 9 refs
Calibration of uranium 232 solution
International Nuclear Information System (INIS)
Galan, M.P.; Acena, M.L.
A method for acertainning the activity by alpha spectroscopy with semiconductor detectors, of a solution of Uranium-232 is presented. It consists of the comparison with a Uranium-233 solution activity previously measured in a gridded ionization chamber of 2 π geometry. The total measurement uncertainty is about +- 0,02. (Author)
Fundamental physics from future weak-lensing calibrated Sunyaev-Zel'dovich galaxy cluster counts
Madhavacheril, Mathew S.; Battaglia, Nicholas; Miyatake, Hironao
Future high-resolution measurements of the cosmic microwave background (CMB) will produce catalogs of tens of thousands of galaxy clusters through the thermal Sunyaev-Zel'dovich (tSZ) effect. We forecast how well different configurations of a CMB Stage-4 experiment can constrain cosmological parameters, in particular, the amplitude of structure as a function of redshift σ8(z ) , the sum of neutrino masses Σ mν, and the dark energy equation of state w (z ). A key element of this effort is calibrating the tSZ scaling relation by measuring the lensing signal around clusters. We examine how the mass calibration from future optical surveys like the Large Synoptic Survey Telescope (LSST) compares with a purely internal calibration using lensing of the CMB itself. We find that, due to its high-redshift leverage, internal calibration gives constraints on cosmological parameters comparable to the optical calibration, and can be used as a cross-check of systematics in the optical measurement. We also show that in contrast to the constraints using the CMB lensing power spectrum, lensing-calibrated tSZ cluster counts can detect a minimal Σ mν at the 3 - 5 σ level even when the dark energy equation of state is freed up.
Standardization of calibration of clinic dosemeters using electric currents and charges
International Nuclear Information System (INIS)
Peres, Marcos Antonio de Lima
Clinical dosimeters used in radiotherapy are calibrated in Latin American countries, including Brazil, as a complete 'system, i.e., ionization chamber and electrometer together. Some countries, as European ones, and USA calibrate them by component, i.e., ionisation chamber apart from electrometer. This method is more advantageous than the previous one, since it makes possible the automation of the calibration process, allowing the acquisition of data related to the chamber and the electrometer measurements independently, as well as the substitution of one of the components, in case of failure. This work proposes a method for standardisation of low intensity electric charge and currents in order to implement electric calibration of electrometers. This will make possible the implementation of a by components calibration technique, by components, of clinical dosimeters in Brazil. The results obtained with the calibration by components prove that the proposed method of standardisation of low electric charges and currents is viable. The difficulties found for the generation and measurement of low intensity electric charges and currents and the procedures adopted for the calibration by components are presented. Additionally, a current source was built to yield reference electric charges that will make possible the quality control clinical dosimeters. This source will also allow the user to identify the defective components of the dosimeters, through a simple verification test. (author)
First Absolutely Calibrated Localized Measurements of Ion Velocity in the MST in Locked and Rotating Plasmas
Baltzer, M.; Craig, D.; den Hartog, D. J.; Nornberg, M. D.; Munaretto, S.
An Ion Doppler Spectrometer (IDS) is used on MST for high time-resolution passive and active measurements of impurity ion emission. Absolutely calibrated measurements of flow are difficult because the spectrometer records data within 0.3 nm of the C+5 line of interest, and commercial calibration lamps do not produce lines in this narrow range . A novel optical system was designed to absolutely calibrate the IDS. The device uses an UV LED to produce a broad emission curve in the desired region. A Fabry-Perot etalon filters this light, cutting transmittance peaks into the pattern of the LED emission. An optical train of fused silica lenses focuses the light into the IDS with f/4. A holographic diffuser blurs the light cone to increase homogeneity. Using this light source, the absolute Doppler shift of ion emissions can be measured in MST plasmas. In combination with charge exchange recombination spectroscopy, localized ion velocities can now be measured. Previously, a time-averaged measurement along the chord bisecting the poloidal plane was used to calibrate the IDS; the quality of these central chord calibrations can be characterized with our absolute calibration. Calibration errors may also be quantified and minimized by optimizing the curve-fitting process. Preliminary measurements of toroidal velocity in locked and rotating plasmas will be shown. This work has been supported by the US DOE.
Characterization of the Sonoran desert as a radiometric calibration target for Earth observing sensors
Angal, Amit; Chander, Gyanesh; Xiong, Xiaoxiong; Choi, Tae-young; Wu, Aisheng
To provide highly accurate quantitative measurements of the Earth's surface, a comprehensive calibration and validation of the satellite sensors is required. The NASA Moderate Resolution Imaging Spectroradiometer (MODIS) Characterization Support Team, in collaboration with United States Geological Survey, Earth Resources Observation and Science Center, has previously demonstrated the use of African desert sites to monitor the long-term calibration stability of Terra MODIS and Landsat 7 (L7) Enhanced Thematic Mapper plus (ETM+). The current study focuses on evaluating the suitability of the Sonoran Desert test site for post-launch long-term radiometric calibration as well as cross-calibration purposes. Due to the lack of historical and on-going in situ ground measurements, the Sonoran Desert is not usually used for absolute calibration. An in-depth evaluation (spatial, temporal, and spectral stability) of this site using well calibrated L7 ETM+ measurements and local climatology data has been performed. The Sonoran Desert site produced spatial variability of about 3 to 5% in the reflective solar regions, and the temporal variations of the site after correction for view-geometry impacts were generally around 3%. The results demonstrate that, barring the impacts due to occasional precipitation, the Sonoran Desert site can be effectively used for cross-calibration and long-term stability monitoring of satellite sensors, thus, providing a good test site in the western hemisphere.
User-friendly freehand ultrasound calibration using Lego bricks and automatic registration.
Xiao, Yiming; Yan, Charles Xiao Bo; Drouin, Simon; De Nigris, Dante; Kochanowska, Anna; Collins, D Louis
As an inexpensive, noninvasive, and portable clinical imaging modality, ultrasound (US) has been widely employed in many interventional procedures for monitoring potential tissue deformation, surgical tool placement, and locating surgical targets. The application requires the spatial mapping between 2D US images and 3D coordinates of the patient. Although positions of the devices (i.e., ultrasound transducer) and the patient can be easily recorded by a motion tracking system, the spatial relationship between the US image and the tracker attached to the US transducer needs to be estimated through an US calibration procedure. Previously, various calibration techniques have been proposed, where a spatial transformation is computed to match the coordinates of corresponding features in a physical phantom and those seen in the US scans. However, most of these methods are difficult to use for novel users. We proposed an ultrasound calibration method by constructing a phantom from simple Lego bricks and applying an automated multi-slice 2D-3D registration scheme without volumetric reconstruction. The method was validated for its calibration accuracy and reproducibility. Our method yields a calibration accuracy of [Formula: see text] mm and a calibration reproducibility of 1.29 mm. We have proposed a robust, inexpensive, and easy-to-use ultrasound calibration method.
Improvements to and Comparison of Static Terrestrial LiDAR Self-Calibration Methods
Directory of Open Access Journals (Sweden)
Preston Hartzell
Full Text Available Terrestrial laser scanners are sophisticated instruments that operate much like high-speed total stations. It has previously been shown that unmodelled systematic errors can exist in modern terrestrial laser scanners that deteriorate their geometric measurement precision and accuracy. Typically, signalised targets are used in point-based self-calibrations to identify and model the systematic errors. Although this method has proven its effectiveness, a large quantity of signalised targets is required and is therefore labour-intensive and limits its practicality. In recent years, feature-based self-calibration of aerial, mobile terrestrial, and static terrestrial laser scanning systems has been demonstrated. In this paper, the commonalities and differences between point-based and plane-based self-calibration (in terms of model identification and parameter correlation are explored. The results of this research indicate that much of the knowledge from point-based self-calibration can be directly transferred to plane-based calibration and that the two calibration approaches are nearly equivalent. New network configurations, such as the inclusion of tilted scans, were also studied and prove to be an effective means for strengthening the self-calibration solution, and improved recoverability of the horizontal collimation axis error for hybrid scanners, which has always posed a challenge in the past.
Calibrating page sized Gafchromic EBT3 films
Energy Technology Data Exchange (ETDEWEB)
Crijns, W.; Maes, F.; Heide, U. A. van der; Van den Heuvel, F. [Department of Radiation Oncology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium); Department ESAT/PSI-Medical Image Computing, Medical Imaging Research Center, KU Leuven, Herestraat 49, 3000 Leuven (Belgium); Department of Radiation Oncology, The Netherlands Cancer Institute-Antoni van Leeuwenhoek Hospital, Plesmanlaan 121, 1066 CX Amsterdam (Netherlands); Department of Radiation Oncology, University Hospitals Leuven, Herestraat 49, 3000 Leuven (Belgium)
Purpose: The purpose is the development of a novel calibration method for dosimetry with Gafchromic EBT3 films. The method should be applicable for pretreatment verification of volumetric modulated arc, and intensity modulated radiotherapy. Because the exposed area on film can be large for such treatments, lateral scan errors must be taken into account. The correction for the lateral scan effect is obtained from the calibration data itself. Methods: In this work, the film measurements were modeled using their relative scan values (Transmittance, T). Inside the transmittance domain a linear combination and a parabolic lateral scan correction described the observed transmittance values. The linear combination model, combined a monomer transmittance state (T{sub 0}) and a polymer transmittance state (T{sub {infinity}}) of the film. The dose domain was associated with the observed effects in the transmittance domain through a rational calibration function. On the calibration film only simple static fields were applied and page sized films were used for calibration and measurements (treatment verification). Four different calibration setups were considered and compared with respect to dose estimation accuracy. The first (I) used a calibration table from 32 regions of interest (ROIs) spread on 4 calibration films, the second (II) used 16 ROIs spread on 2 calibration films, the third (III), and fourth (IV) used 8 ROIs spread on a single calibration film. The calibration tables of the setups I, II, and IV contained eight dose levels delivered to different positions on the films, while for setup III only four dose levels were applied. Validation was performed by irradiating film strips with known doses at two different time points over the course of a week. Accuracy of the dose response and the lateral effect correction was estimated using the dose difference and the root mean squared error (RMSE), respectively. Results: A calibration based on two films was the optimal
Calibrating page sized Gafchromic EBT3 films
International Nuclear Information System (INIS)
Crijns, W.; Maes, F.; Heide, U. A. van der; Van den Heuvel, F.
Purpose: The purpose is the development of a novel calibration method for dosimetry with Gafchromic EBT3 films. The method should be applicable for pretreatment verification of volumetric modulated arc, and intensity modulated radiotherapy. Because the exposed area on film can be large for such treatments, lateral scan errors must be taken into account. The correction for the lateral scan effect is obtained from the calibration data itself. Methods: In this work, the film measurements were modeled using their relative scan values (Transmittance, T). Inside the transmittance domain a linear combination and a parabolic lateral scan correction described the observed transmittance values. The linear combination model, combined a monomer transmittance state (T 0 ) and a polymer transmittance state (T ∞ ) of the film. The dose domain was associated with the observed effects in the transmittance domain through a rational calibration function. On the calibration film only simple static fields were applied and page sized films were used for calibration and measurements (treatment verification). Four different calibration setups were considered and compared with respect to dose estimation accuracy. The first (I) used a calibration table from 32 regions of interest (ROIs) spread on 4 calibration films, the second (II) used 16 ROIs spread on 2 calibration films, the third (III), and fourth (IV) used 8 ROIs spread on a single calibration film. The calibration tables of the setups I, II, and IV contained eight dose levels delivered to different positions on the films, while for setup III only four dose levels were applied. Validation was performed by irradiating film strips with known doses at two different time points over the course of a week. Accuracy of the dose response and the lateral effect correction was estimated using the dose difference and the root mean squared error (RMSE), respectively. Results: A calibration based on two films was the optimal balance between
Review of Calibration Methods for Scheimpflug Camera
Directory of Open Access Journals (Sweden)
Cong Sun
Full Text Available The Scheimpflug camera offers a wide range of applications in the field of typical close-range photogrammetry, particle image velocity, and digital image correlation due to the fact that the depth-of-view of Scheimpflug camera can be greatly extended according to the Scheimpflug condition. Yet, the conventional calibration methods are not applicable in this case because the assumptions used by classical calibration methodologies are not valid anymore for cameras undergoing Scheimpflug condition. Therefore, various methods have been investigated to solve the problem over the last few years. However, no comprehensive review exists that provides an insight into recent calibration methods of Scheimpflug cameras. This paper presents a survey of recent calibration methods of Scheimpflug cameras with perspective lens, including the general nonparametric imaging model, and analyzes in detail the advantages and drawbacks of the mainstream calibration models with respect to each other. Real data experiments including calibrations, reconstructions, and measurements are performed to assess the performance of the models. The results reveal that the accuracies of the RMM, PLVM, PCIM, and GNIM are basically equal, while the accuracy of GNIM is slightly lower compared with the other three parametric models. Moreover, the experimental results reveal that the parameters of the tangential distortion are likely coupled with the tilt angle of the sensor in Scheimpflug calibration models. The work of this paper lays the foundation of further research of Scheimpflug cameras.
Increased Automation in Stereo Camera Calibration Techniques
Directory of Open Access Journals (Sweden)
Brandi House
Full Text Available Robotic vision has become a very popular field in recent years due to the numerous promising applications it may enhance. However, errors within the cameras and in their perception of their environment can cause applications in robotics to fail. To help correct these internal and external imperfections, stereo camera calibrations are performed. There are currently many accurate methods of camera calibration available; however, most or all of them are time consuming and labor intensive. This research seeks to automate the most labor intensive aspects of a popular calibration technique developed by Jean-Yves Bouguet. His process requires manual selection of the extreme corners of a checkerboard pattern. The modified process uses embedded LEDs in the checkerboard pattern to act as active fiducials. Images are captured of the checkerboard with the LEDs on and off in rapid succession. The difference of the two images automatically highlights the location of the four extreme corners, and these corner locations take the place of the manual selections. With this modification to the calibration routine, upwards of eighty mouse clicks are eliminated per stereo calibration. Preliminary test results indicate that accuracy is not substantially affected by the modified procedure. Improved automation to camera calibration procedures may finally penetrate the barriers to the use of calibration in practice.
Vicarious Calibration of Beijing-1 Multispectral Imagers
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Zhengchao Chen
Full Text Available For on-orbit calibration of the Beijing-1 multispectral imagers (Beijing-1/MS, a field calibration campaign was performed at the Dunhuang calibration site during September and October of 2008. Based on the in situ data and images from Beijing-1 and Terra/Moderate Resolution Imaging Spectroradiometer (MODIS, three vicarious calibration methods (i.e., reflectance-based, irradiance-based, and cross-calibration were used to calculate the top-of-atmosphere (TOA radiance of Beijing-1. An analysis was then performed to determine or identify systematic and accidental errors, and the overall uncertainty was assessed for each individual method. The findings show that the reflectance-based method has an uncertainty of more than 10% if the aerosol optical depth (AOD exceeds 0.2. The cross-calibration method is able to reach an error level within 7% if the images are selected carefully. The final calibration coefficients were derived from the irradiance-based data for 6 September 2008, with an uncertainty estimated to be less than 5%.
A water flow calorimeter calibration system
International Nuclear Information System (INIS)
Ullrich, F.T.
Neutral beam systems are instrumented by several water flow calorimeter systems, and some means is needed to verify the accuracy of such systems and diagnose their failures. This report describes a calibration system for these calorimeters. The calibrator consists of two 24 kilowatt circulation water heaters, with associated controls and instrumentation. The unit can supply power from 0 to 48 kW in five coarse steps and one fine range. Energy is controlled by varying the power and the time of operation of the heaters. The power is measured by means of precision power transducers, and the energy is measured by integrating the power with respect to time. The accuracy of the energy measurement is better than 0.5% when the power supplied is near full scale, and the energy resolution is better than 1 kilojoule. The maximum energy delivered is approximately 50 megajoules. The calorimetry loop to be calibrated is opened, and the calibrator is put in series with the calorimeter heat source. The calorimeter is then operated in its normal fashion, with the calibrator used as the heat source. The calibrator can also be used in a stand alone mode to calibrate calorimeter sensors removed from systems
Impact of previously disadvantaged land-users on sustainable ...
African Journals Online (AJOL)
Impact of previously disadvantaged land-users on sustainable agricultural ... about previously disadvantaged land users involved in communal farming systems ... of input, capital, marketing, information and land use planning, with effect on ...
Radiometric calibration of digital cameras using neural networks
Grunwald, Michael; Laube, Pascal; Schall, Martin; Umlauf, Georg; Franz, Matthias O.
Digital cameras are used in a large variety of scientific and industrial applications. For most applications, the acquired data should represent the real light intensity per pixel as accurately as possible. However, digital cameras are subject to physical, electronic and optical effects that lead to errors and noise in the raw image. Temperature- dependent dark current, read noise, optical vignetting or different sensitivities of individual pixels are examples of such effects. The purpose of radiometric calibration is to improve the quality of the resulting images by reducing the influence of the various types of errors on the measured data and thus improving the quality of the overall application. In this context, we present a specialized neural network architecture for radiometric calibration of digital cameras. Neural networks are used to learn a temperature- and exposure-dependent mapping from observed gray-scale values to true light intensities for each pixel. In contrast to classical at-fielding, neural networks have the potential to model nonlinear mappings which allows for accurately capturing the temperature dependence of the dark current and for modeling cameras with nonlinear sensitivities. Both scenarios are highly relevant in industrial applications. The experimental comparison of our network approach to classical at-fielding shows a consistently higher reconstruction quality, also for linear cameras. In addition, the calibration is faster than previous machine learning approaches based on Gaussian processes.
Time scale controversy: Accurate orbital calibration of the early Paleogene
Roehl, U.; Westerhold, T.; Laskar, J.
Timing is crucial to understanding the causes and consequences of events in Earth history. The calibration of geological time relies heavily on the accuracy of radioisotopic and astronomical dating. Uncertainties in the computations of Earth's orbital parameters and in radioisotopic dating have hampered the construction of a reliable astronomically calibrated time scale beyond 40 Ma. Attempts to construct a robust astronomically tuned time scale for the early Paleogene by integrating radioisotopic and astronomical dating are only partially consistent. Here, using the new La2010 and La2011 orbital solutions, we present the first accurate astronomically calibrated time scale for the early Paleogene (47-65 Ma) uniquely based on astronomical tuning and thus independent of the radioisotopic determination of the Fish Canyon standard. Comparison with geological data confirms the stability of the new La2011 solution back to 54 Ma. Subsequent anchoring of floating chronologies to the La2011 solution using the very long eccentricity nodes provides an absolute age of 55.530 ± 0.05 Ma for the onset of the Paleocene/Eocene Thermal Maximum (PETM), 54.850 ± 0.05 Ma for the early Eocene ash -17, and 65.250 ± 0.06 Ma for the K/Pg boundary. The new astrochronology presented here indicates that the intercalibration and synchronization of U/Pb and 40Ar/39Ar radioisotopic geochronology is much more challenging than previously thought.
Technique for production of calibrated metal hydride films
International Nuclear Information System (INIS)
Langley, R.A.; Browning, J.F.; Balsley, S.D.; Banks, J.C.; Doyle, B.L.; Wampler, W.R.; Beavis, L.C.
A technique has been developed for producing calibrated metal hydride films for use in the measurement of high-energy (5--15 MeV) particle reaction cross sections for hydrogen and helium isotopes on hydrogen isotopes. Absolute concentrations of various hydrogen isotopes in the film is expected to be determined to better than ±2% leading to the capacity of accurately measuring various reaction cross sections. Hydrogen isotope concentrations from near 100% to 5% can be made accurately and reproducibly. This is accomplished with the use of high accuracy pressure measurements coupled with high accuracy mass spectrometric measurements of each constituent partial pressure of the gas mixture during loading of the metal occluder films. Various techniques are used to verify the amount of metal present as well as the amount of hydrogen isotopes; high energy ion scattering analysis, PV measurements before, during and after loading, and thermal desorption/mass spectrometry measurements. The most appropriate metal to use for the occluder film appears to be titanium but other occluder metals are also being considered. Calibrated gas ratio samples, previously prepared, are used for the loading gas. Deviations from this calibrated gas ratio are measured using mass spectrometry during and after the loading process thereby determining the loading of the various hydrogen isotopes. These techniques are discussed and pertinent issues presented
Statistical Validation of Calibrated Wind Data Collected From NOAA's Hurricane Hunter Aircraft
Graham, K.; Sears, I. T.; Holmes, M.; Henning, R. G.; Damiano, A. B.; Parrish, J. R.; Flaherty, P. T.
Obtaining accurate in situ meteorological measurements from the NOAA G-IV Hurricane Hunter Aircraft currently requires annual wind calibration flights. This project attempts to demonstrate whether an alternate method to wind calibration flights can be implemented using data collected from many previous hurricane, winter storm, and surveying flights. Wind derivations require using airplane attack and slip angles, airplane pitch, pressure differentials, dynamic pressures, ground speeds, true air speeds, and several other variables measured by instruments on the aircraft. Through the use of linear regression models, future wind measurements may be fit to past statistical models. This method of wind calibration could replace the need for annual wind calibration flights, decreasing NOAA expenses and providing more accurate data. This would help to ensure all data users have reliable data and ultimately contribute to NOAA's goal of building of a Weather Ready Nation.
Building 772 - CERN's new calibration facility for radiation protection instruments is ready to go
Building 772 is becoming the new home of CERN's calibration facility for radiation protection instrumentation. The new laboratory in Prévessin will be a state-of-the-art calibration facility and the first of its kind in both France and Switzerland, offering a wide range of possibilities with respect to radiation fields and instrumentation. New four-axis calibration bench for radiation protection instruments. Civil engineering work started in November 2013 in Prévessin and Building 772 is now finished and ready for inauguration. CERN's calibration facility was previously located in Building 172 in Meyrin. Although still very accurate, the technology used was becoming obsolete and needed replacement. "Having considered different options, the decision was taken to build a new facility fully designed and conceived to meet all international safety and technical requirements of such a laboratory," says Pie...
22 CFR 40.91 - Certain aliens previously removed.
... 22 Foreign Relations 1 2010-04-01 2010-04-01 false Certain aliens previously removed. 40.91... IMMIGRANTS UNDER THE IMMIGRATION AND NATIONALITY ACT, AS AMENDED Aliens Previously Removed § 40.91 Certain aliens previously removed. (a) 5-year bar. An alien who has been found inadmissible, whether as a result...
Method of Calibrating a Force Balance
Parker, Peter A. (Inventor); Rhew, Ray D. (Inventor); Johnson, Thomas H. (Inventor); Landman, Drew (Inventor)
A calibration system and method utilizes acceleration of a mass to generate a force on the mass. An expected value of the force is calculated based on the magnitude and acceleration of the mass. A fixture is utilized to mount the mass to a force balance, and the force balance is calibrated to provide a reading consistent with the expected force determined for a given acceleration. The acceleration can be varied to provide different expected forces, and the force balance can be calibrated for different applied forces. The acceleration may result from linear acceleration of the mass or rotational movement of the mass.
Single Camera Calibration in 3D Vision
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Caius SULIMAN
Full Text Available Camera calibration is a necessary step in 3D vision in order to extract metric information from 2D images. A camera is considered to be calibrated when the parameters of the camera are known (i.e. principal distance, lens distorsion, focal length etc.. In this paper we deal with a single camera calibration method and with the help of this method we try to find the intrinsic and extrinsic camera parameters. The method was implemented with succes in the programming and simulation environment Matlab.
Financial model calibration using consistency hints.
Abu-Mostafa, Y S
We introduce a technique for forcing the calibration of a financial model to produce valid parameters. The technique is based on learning from hints. It converts simple curve fitting into genuine calibration, where broad conclusions can be inferred from parameter values. The technique augments the error function of curve fitting with consistency hint error functions based on the Kullback-Leibler distance. We introduce an efficient EM-type optimization algorithm tailored to this technique. We also introduce other consistency hints, and balance their weights using canonical errors. We calibrate the correlated multifactor Vasicek model of interest rates, and apply it successfully to Japanese Yen swaps market and US dollar yield market.
Dose calibrator user and quality control guide
International Nuclear Information System (INIS)
Blanchis, Philippe; Amiot, Marie-Noelle; Moune, Muriel; Bellanger, Anne-Christine; Chauvenet, Bruno; Verdeau, Eric; Gardin, Isabelle; Martineau, Antoine; Ricard, Marcel; Caselles, Olivier; Guilhem, Marie-Therese; Hapdey, Sebastien; Lisbona, Albert; Bonnot-Lours, Sophie; Dumont, Agnes; Lemercier, Valerie; Rizzo-Padoin, Nathalie
This document is a practical guide for the use and control of dose calibrators which are instruments used for radioactivity measurements. After a recall of the calibrator operation principle, the authors describe all the operations performed on this apparatus all along its lifetime: controls to be performed for device acceptance, aspects to be addressed during installation, controls to be performed before any use, daily controls, more detailed controls, and operations to be performed for maintenance, in case of dysfunctions or for re-calibration
Calibration and evaluation of neutron moisturemeter
International Nuclear Information System (INIS)
Tang Zhangxiong; Hu Jiangchao; Sun Laiyan; Wang Huaihui; Wu Weixue
Factors influencing the calibration curve of neutron moisture meter, such as soil type, texture, volume weight and depth, were studied. When the soil bulk density water content is between 15% to 45%, the calibration curve is approximately a straight line, and the intercept and slope are only influenced by the above factors. The growing plants also influence the calibration curve slightly. The measuring error for top soil (< 20 cm) is larger. The relative error between neutron method and weighing method is about 8%. The neutron method has many advantages such as non-interfering, simple, fast and non-time-delay
Calibration of Ground-based Lidar instrument
DEFF Research Database (Denmark)
Yordanova, Ginka; Gómez Arranz, Paula
This report presents the result of the lidar calibration performed for the given Ground-based Lidar at DTU's test site for large wind turbines at Høvsøre, Denmark. Calibration is here understood as the establishment of a relation between the reference wind speed measurements with measurement...... uncertainties provided by measurement standard and corresponding lidar wind speed indications with associated measurement uncertainties. The lidar calibration concerns the 10 minute mean wind speed measurements. The comparison of the lidar measurements of the wind direction with that from wind vanes...
Calibration of personal dosimeters: Quantities and terminology
International Nuclear Information System (INIS)
Aleinikov, V.E.
The numerical results obtained in the interpretation of individual monitoring of external radiation depend not only on the accurate calibration of the radiation measurement instruments involved, but also on the definition of the quantities in term of which these instruments are calibrated The absence of uniformity in terminology not only makes it difficult to understand properly the scientific and technical literature but can also lead to incorrect interpretation of particular concepts and recommendations. In this paper, brief consideration is given to definition of radiation quantities and terminology used in calibration procedures. (author)
Automated system for the calibration of magnetometers
DEFF Research Database (Denmark)
Petrucha, Vojtech; Kaspar, Petr; Ripka, Pavel
A completely nonmagnetic calibration platform has been developed and constructed at DTU Space (Technical University of Denmark). It is intended for on-site scalar calibration of high-precise fluxgate magnetometers. An enhanced version of the same platform is being built at the Czech Technical Uni...... through custom-made optical incremental sensors. The system is controlled by a microcontroller, which executes commands from a computer. The properties of the system as well as calibration and measurement results will be presented. ©2009 American Institute of Physics...
Calibration Laboratory of the Paul Scherrer Institute
International Nuclear Information System (INIS)
Gmuer, K.; Wernli, C.
Calibration and working checks of radiation protection instruments are carried out at the Calibration Laboratory of the Paul Scherrer Institute. In view of the new radiation protection regulation, the calibration laboratory received an official federal status. The accreditation procedure in cooperation with the Federal Office of Metrology enabled a critical review of the techniques and methods applied. Specifically, personal responsibilities, time intervals for recalibration of standard instruments, maximum permissible errors of verification, traceability and accuracy of the standard instruments, form and content of the certificates were defined, and the traceability of the standards and quality assurance were reconsidered. (orig.) [de
Pioneering efforts to control AIDS. Review: IHO.
Chatterji, A; Sehgal, K
The Indian Health Organisation (IHO) is a nongovernmental organization based in Bombay with more than 12 years experience in HIV/AIDS prevention and control efforts. It has attacked ignorance and prejudice via communication efforts. IHO has created a bond with some hospital systems of Bombay. IHO disseminated information about HIV/AIDS in Bombay's red light districts and has bridged the gap between the city's medical establishment and the community most in need. IHO's aggressive street-level fighting in a sector replete with sensitive issues has somewhat isolated it from mainstream national NGOs involved in HIV/AIDS education and control as well as from the medical establishment and potential partners. IHO funds have been reduced, forcing IHO to reduce intervention programs and responses to field demands. It suffers from a high rate of turnover among middle management staff. IHO's chief advantage is its confidence gained over the past 12 years. IHO has clearly delineated the direction it wants to go: care and support programs for persons affected by HIV/AIDS and for commercial sex workers to allow them to quit prostitution, orphan care, and development of training institutions for the education and motivation of medical personnel on HIV/AIDS care and prevention. It plans to build a hospice for AIDS patients and orphans and a training center. Training activities will vary from one-week orientation programs to three-month certificate courses for medical workers, NGOs, and managers from the commercial sector. IHO is prepared to share its experiences in combating HIV/AIDS in Bombay in a team effort. As official and bilateral funding has been decreasing, IHO has targeted industry for funding. Industry has responded, which enables IHO to sustain its core programs and approaches. IHO observations show a decrease in the number of men visiting red-light districts. IHO enjoys a positive relationship with Bombay's media reporting on AIDS.
Economic growth, biodiversity loss and conservation effort.
Dietz, Simon; Adger, W Neil
This paper investigates the relationship between economic growth, biodiversity loss and efforts to conserve biodiversity using a combination of panel and cross section data. If economic growth is a cause of biodiversity loss through habitat transformation and other means, then we would expect an inverse relationship. But if higher levels of income are associated with increasing real demand for biodiversity conservation, then investment to protect remaining diversity should grow and the rate of biodiversity loss should slow with growth. Initially, economic growth and biodiversity loss are examined within the framework of the environmental Kuznets hypothesis. Biodiversity is represented by predicted species richness, generated for tropical terrestrial biodiversity using a species-area relationship. The environmental Kuznets hypothesis is investigated with reference to comparison of fixed and random effects models to allow the relationship to vary for each country. It is concluded that an environmental Kuznets curve between income and rates of loss of habitat and species does not exist in this case. The role of conservation effort in addressing environmental problems is examined through state protection of land and the regulation of trade in endangered species, two important means of biodiversity conservation. This analysis shows that the extent of government environmental policy increases with economic development. We argue that, although the data are problematic, the implications of these models is that conservation effort can only ever result in a partial deceleration of biodiversity decline partly because protected areas serve multiple functions and are not necessarily designated to protect biodiversity. Nevertheless institutional and policy response components of the income biodiversity relationship are important but are not well captured through cross-country regression analysis.
Validation of SWAT+ at field level and comparison with previous SWAT models in simulating hydrologic quantity
GAO, J.; White, M. J.; Bieger, K.; Yen, H.; Arnold, J. G.
Over the past 20 years, the Soil and Water Assessment Tool (SWAT) has been adopted by many researches to assess water quantity and quality in watersheds around the world. As the demand increases in facilitating model support, maintenance, and future development, the SWAT source code and data have undergone major modifications over the past few years. To make the model more flexible in terms of interactions of spatial units and processes occurring in watersheds, a completely revised version of SWAT (SWAT+) was developed to improve SWAT's ability in water resource modelling and management. There are only several applications of SWAT+ in large watersheds, however, no study pays attention to validate the new model at field level and assess its performance. To test the basic hydrologic function of SWAT+, it was implemented in five field cases across five states in the U.S. and compared the SWAT+ created results with that from the previous models at the same fields. Additionally, an automatic calibration tool was used to test which model is easier to be calibrated well in a limited number of parameter adjustments. The goal of the study was to evaluate the performance of SWAT+ in simulating stream flow on field level at different geographical locations. The results demonstrate that SWAT+ demonstrated similar performance with previous SWAT model, but the flexibility offered by SWAT+ via the connection of different spatial objects can result in a more accurate simulation of hydrological processes in spatial, especially for watershed with artificial facilities. Autocalibration shows that SWAT+ is much easier to obtain a satisfied result compared with the previous SWAT. Although many capabilities have already been enhanced in SWAT+, there exist inaccuracies in simulation. This insufficiency will be improved with advancements in scientific knowledge on hydrologic process in specific watersheds. Currently, SWAT+ is prerelease, and any errors are being addressed.
Calibration of CORSIM models under saturated traffic flow conditions.
This study proposes a methodology to calibrate microscopic traffic flow simulation models. : The proposed methodology has the capability to calibrate simultaneously all the calibration : parameters as well as demand patterns for any network topology....
Calibration and uncertainty in electromagnetic fields measuring methods
International Nuclear Information System (INIS)
Anglesio, L.; Crotti, G.; Borsero, M.; Vizio, G.
Calibration and reliability in electromagnetic field measuring methods are assured by calibration of measuring instruments. In this work are illustrated systems for generation of electromagnetic fields at low and high frequency, calibration standard and accuracy [it
Campaign for vicarious calibration of SumbandilaSat in Argentina
CSIR Research Space (South Africa)
Vhengani, LM
Full Text Available assessment, they are also calibrated post-launch. Various post-launch techniques exist including cross-sensor, solar, lunar and vicarious calibration. Vicarious calibration relies on in-situ measurements of surface reflectance and atmospheric transmittance...
Self-calibration of cone-beam CT geometry using 3D–2D image registration
Ouadah, S; Stayman, J W; Gang, G J; Ehtiati, T; Siewerdsen, J H
Robotic C-arms are capable of complex orbits that can increase field of view, reduce artifacts, improve image quality, and/or reduce dose; however, it can be challenging to obtain accurate, reproducible geometric calibration required for image reconstruction for such complex orbits. This work presents a method for geometric calibration for an arbitrary source-detector orbit by registering 2D projection data to a previously acquired 3D image. It also yields a method by which calibration of simple circular orbits can be improved. The registration uses a normalized gradient information similarity metric and the covariance matrix adaptation-evolution strategy optimizer for robustness against local minima and changes in image content. The resulting transformation provides a 'self-calibration' of system geometry. The algorithm was tested in phantom studies using both a cone-beam CT (CBCT) test-bench and a robotic C-arm (Artis Zeego, Siemens Healthcare) for circular and non-circular orbits. Self-calibration performance was evaluated in terms of the full-width at half-maximum (FWHM) of the point spread function in CBCT reconstructions, the reprojection error (RPE) of steel ball bearings placed on each phantom, and the overall quality and presence of artifacts in CBCT images. In all cases, self-calibration improved the FWHM—e.g. on the CBCT bench, FWHM = 0.86 mm for conventional calibration compared to 0.65 mm for self-calibration (p < 0.001). Similar improvements were measured in RPE—e.g. on the robotic C-arm, RPE = 0.73 mm for conventional calibration compared to 0.55 mm for self-calibration (p < 0.001). Visible improvement was evident in CBCT reconstructions using self-calibration, particularly about high-contrast, high-frequency objects (e.g. temporal bone air cells and a surgical needle). The results indicate that self-calibration can improve even upon systems with presumably accurate geometric calibration and is applicable to situations where conventional
Self-calibration of cone-beam CT geometry using 3D-2D image registration
Ouadah, S.; Stayman, J. W.; Gang, G. J.; Ehtiati, T.; Siewerdsen, J. H.
Robotic C-arms are capable of complex orbits that can increase field of view, reduce artifacts, improve image quality, and/or reduce dose; however, it can be challenging to obtain accurate, reproducible geometric calibration required for image reconstruction for such complex orbits. This work presents a method for geometric calibration for an arbitrary source-detector orbit by registering 2D projection data to a previously acquired 3D image. It also yields a method by which calibration of simple circular orbits can be improved. The registration uses a normalized gradient information similarity metric and the covariance matrix adaptation-evolution strategy optimizer for robustness against local minima and changes in image content. The resulting transformation provides a 'self-calibration' of system geometry. The algorithm was tested in phantom studies using both a cone-beam CT (CBCT) test-bench and a robotic C-arm (Artis Zeego, Siemens Healthcare) for circular and non-circular orbits. Self-calibration performance was evaluated in terms of the full-width at half-maximum (FWHM) of the point spread function in CBCT reconstructions, the reprojection error (RPE) of steel ball bearings placed on each phantom, and the overall quality and presence of artifacts in CBCT images. In all cases, self-calibration improved the FWHM—e.g. on the CBCT bench, FWHM = 0.86 mm for conventional calibration compared to 0.65 mm for self-calibration (p robotic C-arm, RPE = 0.73 mm for conventional calibration compared to 0.55 mm for self-calibration (p < 0.001). Visible improvement was evident in CBCT reconstructions using self-calibration, particularly about high-contrast, high-frequency objects (e.g. temporal bone air cells and a surgical needle). The results indicate that self-calibration can improve even upon systems with presumably accurate geometric calibration and is applicable to situations where conventional calibration is not feasible
Self-calibration of cone-beam CT geometry using 3D–2D image registration
International Nuclear Information System (INIS)
Ouadah, S; Stayman, J W; Gang, G J; Siewerdsen, J H; Ehtiati, T
Robotic C-arms are capable of complex orbits that can increase field of view, reduce artifacts, improve image quality, and/or reduce dose; however, it can be challenging to obtain accurate, reproducible geometric calibration required for image reconstruction for such complex orbits. This work presents a method for geometric calibration for an arbitrary source-detector orbit by registering 2D projection data to a previously acquired 3D image. It also yields a method by which calibration of simple circular orbits can be improved. The registration uses a normalized gradient information similarity metric and the covariance matrix adaptation-evolution strategy optimizer for robustness against local minima and changes in image content. The resulting transformation provides a 'self-calibration' of system geometry. The algorithm was tested in phantom studies using both a cone-beam CT (CBCT) test-bench and a robotic C-arm (Artis Zeego, Siemens Healthcare) for circular and non-circular orbits. Self-calibration performance was evaluated in terms of the full-width at half-maximum (FWHM) of the point spread function in CBCT reconstructions, the reprojection error (RPE) of steel ball bearings placed on each phantom, and the overall quality and presence of artifacts in CBCT images. In all cases, self-calibration improved the FWHM—e.g. on the CBCT bench, FWHM = 0.86 mm for conventional calibration compared to 0.65 mm for self-calibration (p < 0.001). Similar improvements were measured in RPE—e.g. on the robotic C-arm, RPE = 0.73 mm for conventional calibration compared to 0.55 mm for self-calibration (p < 0.001). Visible improvement was evident in CBCT reconstructions using self-calibration, particularly about high-contrast, high-frequency objects (e.g. temporal bone air cells and a surgical needle). The results indicate that self-calibration can improve even upon systems with presumably accurate geometric calibration and is
Determining root correspondence between previously and newly detected objects
Paglieroni, David W.; Beer, N Reginald
A system that applies attribute and topology based change detection to networks of objects that were detected on previous scans of a structure, roadway, or area of interest. The attributes capture properties or characteristics of the previously detected objects, such as location, time of detection, size, elongation, orientation, etc. The topology of the network of previously detected objects is maintained in a constellation database that stores attributes of previously detected objects and implicitly captures the geometrical structure of the network. A change detection system detects change by comparing the attributes and topology of new objects detected on the latest scan to the constellation database of previously detected objects.
Educational Outreach Efforts at the NNDC
International Nuclear Information System (INIS)
Holden, N.E.
Isotopes and nuclides are important in our everyday life. The general public and most students are never exposed to the concepts of stable and radioactive isotopes/nuclides. The National Nuclear Data Center (NNDC) is involved in an international project to develop a Periodic Table of the Isotopes for the educational community to illustrate the importance of isotopes and nuclides in understanding the world around us. This effort should aid teachers in introducing these concepts to students from the high school to the graduate school level
Effort variation regularization in sound field reproduction
DEFF Research Database (Denmark)
Stefanakis, Nick; Jacobsen, Finn; Sarris, Ioannis
In this paper, active control is used in order to reproduce a given sound field in an extended spatial region. A method is proposed which minimizes the reproduction error at a number of control positions with the reproduction sources holding a certain relation within their complex strengths......), and adaptive wave field synthesis (AWFS), both under free-field conditions and in reverberant rooms. It is shown that effort variation regularization overcomes the problems associated with small spaces and with a low ratio of direct to reverberant energy, improving thus the reproduction accuracy...
Multipartite Entanglement Detection with Minimal Effort
Knips, Lukas; Schwemmer, Christian; Klein, Nico; Wieśniak, Marcin; Weinfurter, Harald
Certifying entanglement of a multipartite state is generally considered a demanding task. Since an N qubit state is parametrized by 4N-1 real numbers, one might naively expect that the measurement effort of generic entanglement detection also scales exponentially with N . Here, we introduce a general scheme to construct efficient witnesses requiring a constant number of measurements independent of the number of qubits for states like, e.g., Greenberger-Horne-Zeilinger states, cluster states, and Dicke states. For four qubits, we apply this novel method to experimental realizations of the aforementioned states and prove genuine four-partite entanglement with two measurement settings only.
Auto calibration of a cone-beam-CT
International Nuclear Information System (INIS)
Gross, Daniel; Heil, Ulrich; Schulze, Ralf; Schoemer, Elmar; Schwanecke, Ulrich
CBCT device to demonstrate the achievable spatial resolution of their calibration procedure. Results: Compared to the results published in the most closely related work [K. Yang, A. L. C. Kwan, D. F. Miller, and J. M. Boone, "A geometric calibration method for cone beam CT systems," Med. Phys. 33(6), 1695–1706 (2006)], the simulation proved the greater accuracy of their method, as well as a lower standard deviation of roughly 1 order of magnitude. When compared to another similar approach [L. Smekal, M. Kachelriess, S. E, and K. Wa, "Geometric misalignment and calibration in cone-beam tomography," Med. Phys. 31(12), 3242–3266 (2004)], their results were roughly of the same order of accuracy. Their analysis revealed that the method is capable of sufficiently calibrating out-of-plane angles in cases of larger cone angles when neglecting these angles negatively affects the reconstruction. Fine details in the 3D reconstruction of the spine segment and an electronic device indicate a high geometric calibration accuracy and the capability to produce state-of-the-art reconstructions. Conclusions: The method introduced here makes no requirements on the accuracy of the test object. In contrast to many previous autocalibration methods their approach also includes out-of-plane rotations of the detector. Although assuming a perfect rotation, the method seems to be sufficiently accurate for a commercial CBCT scanner. For devices which require higher dimensional geometry models, the method could be used as a initial calibration procedure.
Validation of a densimeter calibration procedure for a secondary calibration laboratory
International Nuclear Information System (INIS)
Alpizar Herrera, Juan Carlos
A survey was conducted to quantify the need for calibration of a density measurement instrument at the research units at the Sede Rodrigo Facio of the Universidad de Costa Rica. A calibration procedure was documented for the instrument that presented the highest demand in the survey by the calibration service. A study of INTE-ISO/IEC 17025: 2005 and specifically in section 5.4 of this standard was done, to document the procedure for calibrating densimeters. Densimeter calibration procedures and standards were sought from different national and international sources. The method of hydrostatic weighing or Cuckow method was the basis of the defined procedure. Documenting the calibration procedure and creating other documents was performed for data acquisition log, intermediate calculation log and calibration certificate copy. A veracity test was performed using as reference laboratory a laboratory of calibration secondary national as part of the validation process of the documented procedure. The results of the E_n statistic of 0.41; 0.34 and 0.46 for the calibration points 90%, 50% and 10% were obtained for the densimeter scale respectively. A reproducibility analysis of the method was performed with satisfactory results. Different suppliers were contacted to estimate the economic costs of the equipment and materials, needed to develop the documented method of densimeter calibration. The acquisition of an analytical balance was recommended, instead of a precision scale, in order to improve the results obtained with the documented method [es
Exploring a Black Body Source as an Absolute Radiometric Calibration Standard and Comparison with a NIST Traced Lamp Standard
Green, Robert O.; Chrien, Thomas; Sarture, Chuck
Radiometric calibration of the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) is required for the scientific research and application objectives pursued with the spectroscopic measurements. Specifically calibration is required for: inter-comparison of AVIRIS data measured at different locations and at different times; analysis of AVIRIS data with data measured by other instruments; and analysis of AVIRIS data in conjunction with computer models. The primary effect of radiometric calibration is conversion of AVIRIS instrument response values (digitized numbers, or DN) to units of absolute radiance. For example, a figure shows the instrument response spectrum measured by AVIRIS over a portion of Rogers Dry Lake, California, and another figure shows the same spectrum calibrated to radiance. Only the calibrated spectrum may be quantitatively analyzed for science research and application objectives. Since the initial development of the AVIRIS instrument-radiometric calibration has been based upon a 1000-W irradiance lamp with a calibration traced to the National Institute of Standards and Technology (NIST). There are several advantages to this irradiance-lamp calibration approach. First, the considerable effort of NIST backs up the calibration. Second, by changing the distance to the lamp, the output can closely span the radiance levels measured by AVIRIS. Third, this type of standard is widely used. Fourth, these calibrated lamps are comparatively inexpensive. Conversely, there are several disadvantages to this approach as well. First, the lamp is not a primary standard. Second, the lamp output characteristics may change in an unknown manner through time. Third, it is difficult to assess, constrain, or improve the calibration uncertainty delivered with the lamp. In an attempt to explore the effect and potentially address some of these disadvantages a set of analyses and measurements comparing an irradiance lamp with a black-body source have been completed
New calibration technique for KCD-based megavoltage imaging
Samant, Sanjiv S.; Zheng, Wei; DiBianca, Frank A.; Zeman, Herbert D.; Laughter, Joseph S.
In megavoltage imaging, current commercial electronic portal imaging devices (EPIDs), despite having the advantage of immediate digital imaging over film, suffer from poor image contrast and spatial resolution. The feasibility of using a kinestatic charge detector (KCD) as an EPID to provide superior image contrast and spatial resolution for portal imaging has already been demonstrated in a previous paper. The KCD system had the additional advantage of requiring an extremely low dose per acquired image, allowing for superior imaging to be reconstructed form a single linac pulse per image pixel. The KCD based images utilized a dose of two orders of magnitude less that for EPIDs and film. Compared with the current commercial EPIDs and film, the prototype KCD system exhibited promising image qualities, despite being handicapped by the use of a relatively simple image calibration technique, and the performance limits of medical linacs on the maximum linac pulse frequency and energy flux per pulse delivered. This image calibration technique fixed relative image pixel values based on a linear interpolation of extrema provided by an air-water calibration, and accounted only for channel-to-channel variations. The counterpart of this for area detectors is the standard flat fielding method. A comprehensive calibration protocol has been developed. The new technique additionally corrects for geometric distortions due to variations in the scan velocity, and timing artifacts caused by mis-synchronization between the linear accelerator and the data acquisition system (DAS). The role of variations in energy flux (2 - 3%) on imaging is demonstrated to be not significant for the images considered. The methodology is presented, and the results are discussed for simulated images. It also allows for significant improvements in the signal-to- noise ratio (SNR) by increasing the dose using multiple images without having to increase the linac pulse frequency or energy flux per pulse. The
Bayesian calibration of simultaneity in audiovisual temporal order judgments.
Directory of Open Access Journals (Sweden)
Shinya Yamamoto
Full Text Available After repeated exposures to two successive audiovisual stimuli presented in one frequent order, participants eventually perceive a pair separated by some lag time in the same order as occurring simultaneously (lag adaptation. In contrast, we previously found that perceptual changes occurred in the opposite direction in response to tactile stimuli, conforming to bayesian integration theory (bayesian calibration. We further showed, in theory, that the effect of bayesian calibration cannot be observed when the lag adaptation was fully operational. This led to the hypothesis that bayesian calibration affects judgments regarding the order of audiovisual stimuli, but that this effect is concealed behind the lag adaptation mechanism. In the present study, we showed that lag adaptation is pitch-insensitive using two sounds at 1046 and 1480 Hz. This enabled us to cancel lag adaptation by associating one pitch with sound-first stimuli and the other with light-first stimuli. When we presented each type of stimulus (high- or low-tone in a different block, the point of simultaneity shifted to "sound-first" for the pitch associated with sound-first stimuli, and to "light-first" for the pitch associated with light-first stimuli. These results are consistent with lag adaptation. In contrast, when we delivered each type of stimulus in a randomized order, the point of simultaneity shifted to "light-first" for the pitch associated with sound-first stimuli, and to "sound-first" for the pitch associated with light-first stimuli. The results clearly show that bayesian calibration is pitch-specific and is at work behind pitch-insensitive lag adaptation during temporal order judgment of audiovisual stimuli.
Application of calibrated fMRI in Alzheimer's disease.
Lajoie, Isabelle; Nugent, Scott; Debacker, Clément; Dyson, Kenneth; Tancredi, Felipe B; Badhwar, AmanPreet; Belleville, Sylvie; Deschaintre, Yan; Bellec, Pierre; Doyon, Julien; Bocti, Christian; Gauthier, Serge; Arnold, Douglas; Kergoat, Marie-Jeanne; Chertkow, Howard; Monchi, Oury; Hoge, Richard D
Calibrated fMRI based on arterial spin-labeling (ASL) and blood oxygen-dependent contrast (BOLD), combined with periods of hypercapnia and hyperoxia, can provide information on cerebrovascular reactivity (CVR), resting blood flow (CBF), oxygen extraction fraction (OEF), and resting oxidative metabolism (CMRO 2 ). Vascular and metabolic integrity are believed to be affected in Alzheimer's disease (AD), thus, the use of calibrated fMRI in AD may help understand the disease and monitor therapeutic responses in future clinical trials. In the present work, we applied a calibrated fMRI approach referred to as Quantitative O2 (QUO2) in a cohort of probable AD dementia and age-matched control participants. The resulting CBF, OEF and CMRO 2 values fell within the range from previous studies using positron emission tomography (PET) with 15 O labeling. Moreover, the typical parietotemporal pattern of hypoperfusion and hypometabolism in AD was observed, especially in the precuneus, a particularly vulnerable region. We detected no deficit in frontal CBF, nor in whole grey matter CVR, which supports the hypothesis that the effects observed were associated specifically with AD rather than generalized vascular disease. Some key pitfalls affecting both ASL and BOLD methods were encountered, such as prolonged arterial transit times (particularly in the occipital lobe), the presence of susceptibility artifacts obscuring medial temporal regions, and the challenges associated with the hypercapnic manipulation in AD patients and elderly participants. The present results are encouraging and demonstrate the promise of calibrated fMRI measurements as potential biomarkers in AD. Although CMRO 2 can be imaged with 15 O PET, the QUO2 method uses more widely available imaging infrastructure, avoids exposure to ionizing radiation, and integrates with other MRI-based measures of brain structure and function.
Application of calibrated fMRI in Alzheimer's disease
Directory of Open Access Journals (Sweden)
Isabelle Lajoie
Full Text Available Calibrated fMRI based on arterial spin-labeling (ASL and blood oxygen-dependent contrast (BOLD, combined with periods of hypercapnia and hyperoxia, can provide information on cerebrovascular reactivity (CVR, resting blood flow (CBF, oxygen extraction fraction (OEF, and resting oxidative metabolism (CMRO2. Vascular and metabolic integrity are believed to be affected in Alzheimer's disease (AD, thus, the use of calibrated fMRI in AD may help understand the disease and monitor therapeutic responses in future clinical trials. In the present work, we applied a calibrated fMRI approach referred to as Quantitative O2 (QUO2 in a cohort of probable AD dementia and age-matched control participants. The resulting CBF, OEF and CMRO2 values fell within the range from previous studies using positron emission tomography (PET with 15O labeling. Moreover, the typical parietotemporal pattern of hypoperfusion and hypometabolism in AD was observed, especially in the precuneus, a particularly vulnerable region. We detected no deficit in frontal CBF, nor in whole grey matter CVR, which supports the hypothesis that the effects observed were associated specifically with AD rather than generalized vascular disease. Some key pitfalls affecting both ASL and BOLD methods were encountered, such as prolonged arterial transit times (particularly in the occipital lobe, the presence of susceptibility artifacts obscuring medial temporal regions, and the challenges associated with the hypercapnic manipulation in AD patients and elderly participants. The present results are encouraging and demonstrate the promise of calibrated fMRI measurements as potential biomarkers in AD. Although CMRO2 can be imaged with 15O PET, the QUO2 method uses more widely available imaging infrastructure, avoids exposure to ionizing radiation, and integrates with other MRI-based measures of brain structure and function.
Third-party brachytherapy source calibrations and physicist responsibilities: Report of the AAPM Low Energy Brachytherapy Source Calibration Working Group
International Nuclear Information System (INIS)
Butler, Wayne M.; Bice, William S. Jr.; DeWerd, Larry A.; Hevezi, James M.; Huq, M. Saiful; Ibbott, Geoffrey S.; Palta, Jatinder R.; Rivard, Mark J.; Seuntjens, Jan P.; Thomadsen, Bruce R.
The AAPM Low Energy Brachytherapy Source Calibration Working Group was formed to investigate and recommend quality control and quality assurance procedures for brachytherapy sources prior to clinical use. Compiling and clarifying recommendations established by previous AAPM Task Groups 40, 56, and 64 were among the working group's charges, which also included the role of third-party handlers to perform loading and assay of sources. This document presents the findings of the working group on the responsibilities of the institutional medical physicist and a clarification of the existing AAPM recommendations in the assay of brachytherapy sources. Responsibility for the performance and attestation of source assays rests with the institutional medical physicist, who must use calibration equipment appropriate for each source type used at the institution. Such equipment and calibration procedures shall ensure secondary traceability to a national standard. For each multi-source implant, 10% of the sources or ten sources, whichever is greater, are to be assayed. Procedures for presterilized source packaging are outlined. The mean source strength of the assayed sources must agree with the manufacturer's stated strength to within 3%, or action must be taken to resolve the difference. Third party assays do not absolve the institutional physicist from the responsibility to perform the institutional measurement and attest to the strength of the implanted sources. The AAPM leaves it to the discretion of the institutional medical physicist whether the manufacturer's or institutional physicist's measured value should be used in performing dosimetry calculations
Calibration methodology application of kerma area product meters in situ: Preliminary results
Costa, N. A.; Potiens, M. P. A.
The kerma-area product (KAP) is a useful quantity to establish the reference levels of conventional X-ray examinations. It can be obtained by measurements carried out with a KAP meter on a plane parallel transmission ionization chamber mounted on the X-ray system. A KAP meter can be calibrated in laboratory or in situ, where it is used. It is important to use one reference KAP meter in order to obtain reliable quantity of doses on the patient. The Patient Dose Calibrator (PDC) is a new equipment from Radcal that measures KAP. It was manufactured following the IEC 60580 recommendations, an international standard for KAP meters. This study had the aim to calibrate KAP meters using the PDC in situ. Previous studies and the quality control program of the PDC have shown that it has good function in characterization tests of dosimeters with ionization chamber and it also has low energy dependence. Three types of KAP meters were calibrated in four different diagnostic X-ray equipments. The voltages used in the two first calibrations were 50 kV, 70 kV, 100 kV and 120 kV. The other two used 50 kV, 70 kV and 90 kV. This was related to the equipments limitations. The field sizes used for the calibration were 10 cm, 20 cm and 30 cm. The calibrations were done in three different cities with the purpose to analyze the reproducibility of the PDC. The results gave the calibration coefficient for each KAP meter and showed that the PDC can be used as a reference instrument to calibrate clinical KAP meters.
International Efforts for the Nuclear Security
International Nuclear Information System (INIS)
Yoo, Ho Sik; Kwak, Sung Woo; Lee, Ho Jin; Shim, Hye Won; Lee, Jong Uk
Many concerns have been focused on the nuclear security since the 9.11. With increasing the threat related to nuclear material and nuclear facilities, the demand of strengthening the international physical protection system has been raised. Along with this, the international communities are making their efforts to increase nuclear security. The agreement of revising the 'Convention on Physical Protection of Nuclear Materials'(hereafter, CPPNM), which was held in Vienna on the July of 2005, was one of these efforts. U.N is also preparing the 'International Convention for the Suppression of Acts of Nuclear Terrorism' to show its firm resolution against nuclear terror. It is important to understand what measures should be taken to meet the international standard for establishing national physical protection system. To do this, international trend on the physical protection system such as CPPNM and U.N. convention should be followed. This paper explains about the content of the CPPNM and U.N convention. They will be helpful to consolidate the physical protection system in Korea
The 2007 ESO Instrument Calibration Workshop
Kaufer, Andreas; ESO Workshop
The 2007 ESO Instrument Calibration workshop brought together more than 120 participants with the objective to a) foster the sharing of information, experience and techniques between observers, instrument developers and instrument operation teams, b) review the actual precision and limitations of the applied instrument calibration plans, and c) collect the current and future requirements by the ESO users. These present proceedings include the majority of the workshop's contributions and document the status quo of instrument calibration at ESO in large detail. Topics covered are: Optical Spectro-Imagers, Optical Multi-Object Spectrographs, NIR and MIR Spectro-Imagers, High-Resolution Spectrographs, Integral Field Spectrographs, Adaptive Optics Instruments, Polarimetric Instruments, Wide Field Imagers, Interferometric Instruments as well as other crucial aspects such as data flow, quality control, data reduction software and atmospheric effects. It was stated in the workshop that "calibration is a life-long l...
Construction of calibration curve for accountancy tank
International Nuclear Information System (INIS)
Kato, Takayuki; Goto, Yoshiki; Nidaira, Kazuo
Tanks are equipped in a reprocessing plant for accounting solution of nuclear material. The careful measurement of volume in tanks is very important to implement rigorous accounting of nuclear material. The calibration curve relating the volume and level of solution needs to be constructed, where the level is determined by differential pressure of dip tubes. Several calibration curves are usually employed, but it's not explicitly decided how many segment are used, where to select segment, or what should be the degree of polynomial curve. These parameters, i.e., segment and degree of polynomial curve are mutually interrelated to give the better performance of calibration curve. Here we present the construction technique of giving optimum calibration curves and their characteristics. (author)
An Exact Confidence Region in Multivariate Calibration
Mathew, Thomas; Kasala, Subramanyam
In the multivariate calibration problem using a multivariate linear model, an exact confidence region is constructed. It is shown that the region is always nonempty and is invariant under nonsingular transformations.
DECal: A Spectrophotometric Calibration System For DECam.
Rheault, Jean-Philippe; DePoy, D. L.; Marshall, J. L.; Prochaska, T.; Allen, R.; Wise, J.; Martin, E.
We present preliminary results for a spectrophotometric calibration system that is being implemented as part of the DES DECam project at the Blanco 4 meter at CTIO. Our calibration system uses a 2nm wide tunable source to measure the instrumental response function of the telescope from 300nm up to 1100nm. This calibration will be performed regularly to monitor any change in the transmission function. The system consists of a monochromator based tunable light source that provides illumination on a dome flat that is monitored by calibrated photodiodes and allow us to measure the throughput as a function of wavelength. Our system has an output power of 2 mW, equivalent to a flux of approximately 800 photons/s/pixel on DECam. Preliminary results of the measure of the throughput of the telescope will be presented.
Beta calibration and dosimetry at IPEN
International Nuclear Information System (INIS)
Caldas, L.V.E.
A commercial extrapolation chamber (PTW, Germany) was tested in different beta radiation fields and its properties investigated. Its usefullness for beta radiation calibration and dosimetry was demonstrated. (Author) [pt
HPS instrument calibration laboratory accreditation program
Energy Technology Data Exchange (ETDEWEB)
Masse, F.X; Eisenhower, E.H.; Swinth, K.L.
The purpose of this paper is to provide an accurate overview of the development and structure of the program established by the Health Physics Society (HPS) for accrediting instrument calibration laboratories relative to their ability to accurately calibrate portable health physics instrumentation. The purpose of the program is to provide radiation protection professionals more meaningful direct and indirect access to the National Institute of Standards and Technology (NIST) national standards, thus introducing a means for improving the uniformity, accuracy, and quality of ionizing radiation field measurements. The process is designed to recognize and document the continuing capability of each accredited laboratory to accurately perform instrument calibration. There is no intent to monitor the laboratory to the extent that each calibration can be guaranteed by the program; this responsibility rests solely with the accredited laboratory.
Calibration beads containing luminescent lanthanide ion complexes
The reliability of lanthanide luminescence measurements, by both flow cytometry and digital microscopy, will be enhanced by the availability of narrow-band emitting lanthanide calibration beads. These beads can also be used to characterize spectrographic instruments, including mi...
... CLINICAL CHEMISTRY AND CLINICAL TOXICOLOGY DEVICES Clinical Chemistry Test Systems § 862.1150 Calibrator... to establish points of reference that are used in the determination of values in the measurement of...
Calibration of pressure gauge for Cherenkov detector
Saponjic, Nevena
Solartron/Hamilton pressure gauges are used to monitor the gas pressure in the particle beam detectors installed in the experimental areas. Here is description of the test bench for the calibration of these gauges in Labview.
ATLAS Tile calorimeter calibration and monitoring systems
Marjanovic, Marija; The ATLAS collaboration
The ATLAS Tile Calorimeter (TileCal) is the central section of the hadronic calorimeter of the ATLAS experiment. This sampling calorimeter uses steel plates as absorber and scintillating tiles as active medium. The light produced by the passage of charged particles is transmitted by wavelength shifting fibers to photo-multiplier tubes (PMTs), located in the outer part of the calorimeter. The readout is segmented into about 5000 cells, each one being read out by two PMTs in parallel. To calibrate and monitor the stability and performance of the full readout chain during the data taking, a set of calibration sub-systems is used. The TileCal calibration system comprises Cesium radioactive sources, laser, charge injection elements, and an integrator based readout system. Combined information from all systems allows to monitor and to equalize the calorimeter response at each stage of the signal evolution, from scintillation light to digitization. Calibration runs are monitored from a data quality perspective and u...
The Observability Calibration Test Development Framework
Energy Technology Data Exchange (ETDEWEB)
Endicott-Popovsky, Barbara E.; Frincke, Deborah A.
Abstract— Formal standards, precedents, and best practices for verifying and validating the behavior of low layer network devices used for digital evidence-collection on networks are badly needed— initially so that these can be employed directly by device owners and data users to document the behaviors of these devices for courtroom presentation, and ultimately so that calibration testing and calibration regimes are established and standardized as common practice for both vendors and their customers [1]. The ultimate intent is to achieve a state of confidence in device calibration that allows the network data gathered by them to be relied upon by all parties in a court of law. This paper describes a methodology for calibrating forensic-ready low layer network devices based on the Flaw Hypothesis Methodology [2,3].
Monitoring coordinate measuring machines by calibrated parts
International Nuclear Information System (INIS)
Weckenmann, A; Lorz, J
Coordinate measuring machines (CMM) are essential for quality assurance and production control in modern manufacturing. Due to the necessity of assuring traceability during the use of CMM, interim checks with calibrated objects carried out periodically. For this purpose usually special artefacts like standardized ball plates, hole plates, ball bars or step gages are measured. Measuring calibrated series parts would be more advantageous. Applying the substitution method of ISO 15530-3: 2000 such parts can be used. It is less cost intensive and less time consuming than measuring expensive special standardized objects in special programmed measurement routines. Moreover, the measurement results can directly compare with the calibration values; thus, direct information on systematic measurement deviations and uncertainty of the measured features are available. The paper describes a procedure for monitoring horizontal-arm CMMs with calibrated sheet metal series parts