I have about 5544 runs where I am trying to classify it as failure or success. Here the number of runs that lead to failure is only 64 and rest is sucess. In that case when I try to use SVM should I make the number of classes equal? Will this affect the results?
I have a training set with about 3000 positive instances and 3000 negative instances. But my test data set is pretty much un-balanced. The positive set only has 50 instances and negative has 1500 instances.This causes the precision very low. Are there any approaches to solve this problem? I use SVM to build classifier.
Is a sub-shell the same thing as a child-shell There are this two names: a subshell and a child-shell.  Yes, a child process will be started by any of this:  sh -c 'echo "Hello"' ( echo "hello" ) echo "$(echo "hello") echo "hello" | cat   Are all equivalent and share the same name? Do all share the same properties?    POSIX :     A shell execution environment consists of ....   But the last paragraph of above link has this:     A subshell environment shall be created as a duplicate of the shell environment, except that signal traps that are not being ignored shall be set to the default action.    And specially:     Command substitution, commands that are grouped with parentheses, and asynchronous lists shall be executed in a subshell environment. Additionally, each command of a multi-command pipeline is in a subshell environment; ....   The sh -c 'echo "Hello"' is not included there, should that be called a subshell also? Get in vs. get on Possible Duplicate:          I'm an EFL (English as a foreign language) teacher and I haven't been able to come up with a good principle for which preposition to use after get when referring to transportation.  Some examples:   Get in:   a car/taxi/van/truck, etc.  Get on:   a bus/plane/bike/truck, etc.    How can one choose whether to use in or on? Note that in some cases, such as the example with truck, either preposition is possible but the choice affects the meaning.  I've been telling my students that there is no rule, so they just have to memorize which preposition to use, but I'm really hoping I'm wrong.  This question would be better suited for the upcoming  Stack Exchange, but it hasn't entered beta yet. More . Is Linux a Unix? So, there are lots of different versions of Unix out there: HP-UX, AIX, BSD, etc. Linux is considered a Unix clone rather than an implementation of Unix. Are all the "real" Unices actual descendants of the original? If not, what separates Linux from Unix? Render looks darker than Look Dev mode Receiving Push Notifications while in background Stars and pins are retained when chat messages are moved! . If you filter out a range of wavelengths, how can you calculate the energy from the remaining wavelengths?   To make it concrete, say we filter everything below 450nm or alternatively above 700nm. Why do people have darker skin in sunnier climates? I don't understand why darker skin is advantageous in hotter climates. Wouldn't it absorb more of the heat? I have heard that it reduces the incidence of cancer, but I would think absorbing more radiation would increase the risk? Ideas to improve website loading speed? Are there any ways in which I can improve the loading speed of a website?  I know that Google is really pushing loading speeds and with the popularity of mobile websites it's now imperative that sites load quickly. How vibration sensitive are hard disk drives? I've gotten my hands on a seriously cheap laptop grade 2.5 inch drive. I'm intending to use one on a desktop that doesn't have 2.5 inch bays as a boot drive. While I know there are adapters available, I know its fairly common with SSDs to simply velcro/tape the drive somewhere. I'm wondering if I can do the same with a laptop hard drive.  One issue I see here is SSDs are fairly insensitive to vibration, while hard drives are. Just how vibration sensitive are drives? Would a jerry rigged mount need to take this into account? I am interested in good integer approximation from below and from above for binary Log(N!).  and  provides only a general idea but not exact values. In other words I need integers A and B so that  A &lt;= Log(N!) &lt;= B I'm missing all the usual processing tools in the Vector menu in QGIS 2.16 (eg vector overlay, analysis, etc). They do appear in the processing toolbox but there's no sign of them in the Vector menu. Has anyone come across this issue? Proving the second root of a quadratic equation If $\alpha$ is a root of the equation $4x^2+2x-1=0$, then prove that $4\alpha^3-3\alpha$ is the other root. How do I proceed? The sum of the roots, the product of the roots lead me nowhere. Should I find the roots of the equation and substitute in the given two expressions of $\alpha$ and check whether manipulating the first root gives me the second root (which seems much complicated), or is there any other way? How can I safely prototype a mains power circuit? I'm building a device that has a mains power component, which I need to prototype before building to make sure everything works. I know I need to make sure wiring—and insulation!—is thick enough to cope with the higher current, and that I need to make sure there's enough space between exposed components so there's no arcing. I'll also be stashing whatever I prototype in a nice, insulated box before applying power, and I'll be include a small-value (250mA) fuse just in case. I'll be considering everything double-insulated rather than earthed (plastic enclosure, and there's nothing I'll need to touch while it's operating).  My plan is to solder (through-hole) components directly to each other, then insulate everything (with heatshrink tubing or electrical tape) as much as possible, then use screw-type cable joiners to connect the power cable.  I know I can't use traditional prototyping tools such as breadboards and stripboard for mains voltages, but what can I use to make prototyping at mains voltages easier?  (To be clear, 'mains voltage' in my area means 230V AC +10/-6% at 50Hz; GPOs are generally rated at 10A.) How can I tell what year my bike was made? Are there any clones/alternatives for running a Stack Exchange style Q&A site? ConcurrentModificationException Woes MacOS 10.14 Mojave public beta public Wi-Fi problem I can not connect to a single public Wi-Fi hotspot that does not require a password but instead shows a pop-up window pointed to captive.apple.com  The pop-up opens blank with the error "The web page couldn't be loaded"  Any idea on how to fix this? optexp environment error when compiling with XeLaTeX I have troubles with optexp environment. There is a code  \documentclass[pstricks,margin=12pt]{standalone}  \usepackage{pst-optexp}  \begin{document} \begin{pspicture}(3.2,5) \pnodes(0,3){A}(1,3){BS}(3,3){M1}(1,5){M2}(1,1){PD} \psset{mirrortype=extended, mirrordepth=0.2}  \begin{optexp} \beamsplitter[bsstyle=plate, compname=BS](A)(BS)(PD) \mirror[compname=M1](BS)(M1)(BS) \mirror[compname=M2, variable](BS)(M2)(BS) \lens[compname=L](BS)(PD) \optdetector[compname=Det, dettype=diode](BS)(PD) \addtopsstyle{Beam}{beamwidth=0.2, fillstyle=solid,fillcolor=green!20!white} \drawwidebeam(A){BS}{M1}{BS}{M2}{BS}{L}{Det} \end{optexp} \end{pspicture}  \end{document}   and the result is this    and I get "MiKTeX GPL Ghostscript 9.19: Unrecoverable error, exit code 1" error. When I remove optexp environment, so  \documentclass[pstricks,margin=12pt]{standalone}  \usepackage{pst-optexp}  \begin{document} \begin{pspicture}(3.2,5) \pnodes(0,3){A}(1,3){BS}(3,3){M1}(1,5){M2}(1,1){PD} \psset{mirrortype=extended, mirrordepth=0.2}   \beamsplitter[bsstyle=plate, compname=BS](A)(BS)(PD) \mirror[compname=M1](BS)(M1)(BS) \mirror[compname=M2, variable](BS)(M2)(BS) \lens[compname=L](BS)(PD) \optdetector[compname=Det, dettype=diode](BS)(PD) \addtopsstyle{Beam}{beamwidth=0.2, fillstyle=solid,fillcolor=green!20!white} \drawwidebeam(A){BS}{M1}{BS}{M2}{BS}{L}{Det}  \end{pspicture}  \end{document}   the result is     which is correct but optical components are behind beam. I use XeLatex. What am I doing wrong? Which packages are missing? Thank you (example is from manual "Drawing optical experimental setups" where the code works correctly). Why doesn't the Related question list show that questions are closed? I saw a question on Meta that was obviously going to be a duplicate:        And indeed, looking at the "Related" questions list for that question showed a number of duplicates:    Being the good citizen I am, I tried to vote to close (technically Flag as duplicate as I've not got the rep here to vote to close) it as an Exact Duplicate only to find myself falling into a rabbit hole of Closed, Duplicate questions. Is there any way to flag a closed question as such in the Related list?  Mostly because the first one I picked was closed as a duplicate of the second one, which was closed as a duplicate of the one that is now listed as the duplicate/linked answer.   Edit to respond to comment:  I take the point about "not voting to close on title alone", and normally wouldn't, however as the questions had identical titles, and it's pretty clear what they should be asking, I clicked the first one:    which lead to:  which leads to:  - but I'd got bored following links and didn't check that one as the first two were identical, so assumed this was too and didn't want to see how deep the rabbit hole led.   In the related list, there's only one other question in there that is an exact duplicate, but hasn't (currently) been closed as such which is:      Reasoning for highlighting closed questions:  The "Questions with similar titles" does display the closed titles when asking the question, so it should be fairly possible to include.  If there are clearly duplicate titles, then as a reader/reviewer would be helpful to know which ones are already closed as duplicates so you can either:   Use the remaining open questions to focus on which of those is the canonical answer to close this with. Use the closed questions to find the canonical answer (which failed for me with my route of clicks).