{'fraction_non_alphanumeric': 0.02048032021347565, 'fraction_numerical': 0.00733822548365577, 'mean_word_length': 5.357506361323155, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Level Assessment Criterion and Method for C4ISR Systems Interoperability

In this paper, the concept of C4ISR systems interoperability is analyzed and the difference compared with traditional system interoperability is presented. The influencing factors of C4ISR system interoperability is analyzed from the overall framework of the US military global information grid. Six attributes including structure, application, facility, security, operation and maintenance, and data are selected. The selection process of evaluation attributes is described. Based on the enhanced interoperability maturity mode, the C4ISR system level attribute model is given by combing with the development trend of C4ISR system technology system. The grade of maturity and an evaluation index system for C4ISR systems interoperability are built and the index level reference model is designed. Combining qualitative assessment with quantitative assessment, an index synthesis criterion based on the mapping model and the corresponding interoperability level evaluation method for C4ISR systems are proposed to provide a specific method model for measuring the interoperability level of the C4ISR system.


Introduction
Command, Control, Communication, Computing, Intelligence, Surveillance, Reconnaissance (C 4 ISR) systems is set the functions including command and control, early warning detection, communication, weapon control, and the other operation information assurance as one of military information system, which can be used to obtain/process/pass the military information and operate decision support, command and control, and battle field management [1] [2].
Interoperability is a key factor to evaluate the capacity of systems. The definition of system interoperability has been proposed firstly in 1997 by US DoD [3]. The best known definition says that interoperability is the capacity that two or more than two systems of components to exchange information and use the exchanged information [4].
The systems of systems (SoS) is set of independent systems, which own their functions and can emerge new higher capacity when they are aggregated together. For joint operation, SoS represents the joint systems have the capacity of cooperation and interoperability [5].
The SoS interoperability refers to the ability to coordinate the work through the interaction of information between system elements, thus achieving information advantages. When the system elements complete the task, they coordinate other elements through information exchange to perform corresponding information activities to meet the needs of the task [6]. The concept of SoS interoperability is the extension of the concept of system interoperability. In addition to the information exchange, information understanding and collaborative coordination among the system elements, the impact of factors for system interoperability such as the rationality of the architecture， security of the information exchange environment, efficiency of operation and maintenance

1 The concept of C 4 ISR systems interoperability concept
The C 4 ISR system is a SoS consisting of multiple systems such as intelligence, command and control, weapon control, operational support, and communication. From a SoS perspective, we propose that C 4 ISR system interoperability concept contains two respects based on the overall structure of the C 4 ISR system. On one hand, each system in the C 4 ISR system exchanges data, information, services and other resources to obtain the sharing of these resources among systems and the circulation in the system, so that the system can obtain mutual cooperation and promote the overall capacity of the C 4 ISR system. On the other hand, the C 4 ISR system flexibly configures the business relationship between systems for certain mission through the functional handover between systems, and enhances the ability of the C 4 ISR system to adapt to tasks and environment changes.
Compared with traditional interoperability, C 4 ISR systems interoperability has the following differences and extensions: 1) Traditional system interoperability mainly considers the information interaction between systems. The interoperability of C 4 ISR systems not only considers the interaction of data, information, service and other resources in the system, but also considers the circulation of these resources in the whole system, and the mutual cooperation between systems not only aims at local collaborative tasks, but aims to maximize the overall capabilities of the system. 2) Traditional system interoperability mainly considers the collaboration ability between systems through information interaction. The interoperability of C 4 ISR systems not only considers the ability of systems to cooperate with each other, but also considers the adaptability of network information system under complex and environmental changes. Each system can be configured to form a functional handover between systems.

Attribute composition
The origin of the US military global information grid (GIG) theory is to solve the problem of the inconsistency of the technical system for military information systems and poor interoperability. It aims to construct a grid information system with the information transmission capability between any two or more points in the world [12]. Therefore, it is possible to analyze the factors affecting the interoperability of the C 4 ISR systems from the overall framework of GIG, and to extract the evaluation attributes of the C 4 ISR systems interoperability assessment.
In the five layers of GIG overall framework, each layer contains content that affects interoperability. In the base layer, the architecture can standardize the various elements of the system from the top of the system, so that the various elements of the system are developed and constructed based on the same specifications. Whether the system can achieve the overall traction from the top layer to achieve interoperability; in the communication layer, the infrastructure of optical fiber, satellite, basic information system network, the scope of communication coverage, performance and other aspects determine whether the system can In the computing layer, the completeness and standardization of various types of databases determine whether each system in the system exchanges and shares data based on the same data format; in the global application layer, various tasks The system determines the interaction performance of the system software in the aspects of the openness and interaction mode of the application software. At the same time, the management measures and security systems that pass through the layers determine the interoperability of the system in sequence, and the physical devices such as communication and software. Security, data, and operational security also determine the boundaries of interoperability.
Therefore, this paper evaluates the interoperability of C 4 ISR systems from the top-level architecture, main infrastructure, applications, data, and operation and maintenance. Each attribute describes the key points that affect the interoperability of the C 4 ISR system from their respective perspectives.
Among them, the structural attribute is the evaluation of the business processing relationship between the components of the information system in the C 4 ISR system; the application attribute is the evaluation of the software interoperability maturity; the facility attribute is the evaluation of the network interoperability maturity; the security attribute is the security The evaluation of confidentiality maturity; the operation and maintenance attribute is the maturity evaluation of the information resource scheduling ability; the data attribute is the evaluation of the data structure modeling maturity.

Level model
From the perspective of forming the C 4 ISR system information advantage and improving the adaptability of the C 4 ISR system, the C 4 ISR system interoperability level model is constructed. As shown in Table 1, the six attributes corresponding to the six attributes are given in the model. Compared with the enhanced interoperability maturity model, the C 4 ISR system interoperability level model further considers the impact of intelligence on the interoperability of C 4 ISR systems, and defines the iconic features of the six attributes of structure, facility, application, data, security, and operation and maintenance in the fifth level of adaptation as structural self-reconfiguration, softwaredefined network, functional self-synchronization, knowledge model, system self-protection, intelligent operation and maintenance.

3 C 4 ISR system interoperability index system
In order to quantitatively evaluate the interoperability of C 4 ISR system, firstly, based on the C 4 ISR system interoperability level model, attribute index trees can be constructed for each of the six attributes. Take the attribute of architecture as an example, the corresponding attribute index trees are given, as shown in Figure 1. Each attribute indicator tree further constitutes the C 4 ISR system interoperability evaluation index system

C 4 ISR systems interoperability level evaluation method
System capacity assessment refers to the process of evaluating the intrinsic ability of a certain aspect of the system by analyzing the factors affecting the inherent potential of the system through pre-set rules and approaches. For the evaluation of interoperability, most of the existing evaluation methods are qualitative evaluation by evaluation model. Combining qualitative evaluation with quantitative evaluation, an interoperability level assessment method for C 4 ISR system is given in this paper.

Index calculation
In order to evaluate the grades of each attribute, it is first necessary to obtain the evaluation results of the three-level indicators in each attribute indicator tree, and then further integrate the three-level index evaluation results, and gradually obtain the second-level indicators and the evaluation results of the respective attributes. The method of evaluating the three-level indicator and the method of comprehensively obtaining the evaluation result of the second-level indicator can be designed according to the characteristics of the indicator itself, and the qualitative evaluation method or the quantitative evaluation method can be adopted.

Index level reference model
According to the C 4 ISR system interoperability evaluation index system, the reference values corresponding to different levels and the secondary indicators in each attribute index system are analyzed, and an interoperability index mapping model is constructed, as shown in Table 2, where the setting of the target value should be given with the evaluation process of the corresponding index. Taking the indicators of structural attributes and facility attributes as an example, the index values of the two secondary indicators at 0-5 level are respectively given. It can be seen that the mapping model does not require the indicators to correspond to the respective levels. The values are different, because the final level of each attribute and the level of interoperability of the C 4 ISR system are a comprehensive evaluation result obtained by taking into account the various indicator levels.

Index mapping model
The results of the three-level index and the second-level index in each attribute indicator tree can be obtained by the index calculation method, and the result of the second-level index is compared with the reference value of each level in the reference model of the C 4 ISR system inter-operability evaluation index level, and one can be obtained. The index mapping model, for example, assumes that the calculation result of the syntax layer indicator is A0=1, and the evaluation result of the facility controllability index is controllable, and the indicator mapping model is as shown in Table 3.

Comprehensive guidelines for indicators
According to the command mapping model, the evaluation results of each secondary indicator are combined to obtain the level corresponding to each attribute. The comprehensive guidelines for indicators are as follows: The six attributes of structure, application, facility, security, operation and maintenance, and data are numbered from 1 to 6, which are set to the first to sixth attributes, respectively, for the i-th (i=1, 2, 3, 4, 5, 6) The attribute indicator tree corresponding to each attribute is such that the corresponding level set of the jth (j=1, 2, 3) three-level index result in the interoperation contour is G ij . The maximum values of the three sets G i1 , G i2 , and G i3 are respectively taken out, and the three sets are sorted according to the size of the three maximum values taken, so that the set with the smallest maximum value is {G i } min , and the maximum value is the largest. For {G i } max , the set of the maximum value is {G i } mid , then the maximum value of {G i } min is the level of the i-th attribute.
For example, for structural attributes, the corresponding level sets of the three three-level indicators in the interoperable contour are G 11 ={1,2,3,4,5}, G 12 ={1,2,3,4,5}, G 13 ={3}, in the three sets. The maximum values are 5, 5, and 3, respectively, so the minimum value 3 of the three is taken as the level of the application attribute, that is, the structural attribute level is 3 (integration level).

Determine the interoperability level of the C 4 ISR system
The C 4 ISR system interoperability level can be obtained by combining the evaluation results of each attribute level. There are many methods that can be used to comprehensively derive the total evaluation results by using a set of evaluation results. The following two methods are available.

Method 2:
Comprehensive evaluation methodComprehensive results such as analytic hierarchy process, grey comprehensive evaluation method and fuzzy evaluation method are used to obtain the comprehensive results of the interoperability level of C 4 ISR system.

Conclusion
In this paper, the concept connotation and influencing factors of C 4 ISR system interoperability is analyzed, the selection process of structure, application, facility, security, operation and maintenance, and data evaluation attributes is described. Combined with the development trend of C 4 ISR system technology system, it constructs C 4 ISR system level attribute. The model, based on the six attributes corresponding to the six levels of landmark features, constructed a C 4 ISR system interoperability index system with six attribute indicator trees, using a combination of qualitative evaluation and quantitative evaluation, and constructed the C 4 ISR system interoperability index. The level reference model and the mapping model propose the C 4 ISR system interoperability level evaluation method and criteria, and provide a specific method model for measuring the interoperability level of the C 4 ISR system.