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  • Are there any downsides in using C++ for network daemons?

    - by badcat
    Hey guys! I've been writing a number of network daemons in different languages over the past years, and now I'm about to start a new project which requires a new custom implementation of a properitary network protocol. The said protocol is pretty simple - some basic JSON formatted messages which are transmitted in some basic frame wrapping to have clients know that a message arrived completely and is ready to be parsed. The daemon will need to handle a number of connections (about 200 at the same time) and do some management of them and pass messages along, like in a chat room. In the past I've been using mostly C++ to write my daemons. Often with the Qt4 framework (the network parts, not the GUI parts!), because that's what I also used for the rest of the projects and it was simple to do and very portable. This usually worked just fine, and I didn't have much trouble. Being a Linux administrator for a good while now, I noticed that most of the network daemons in the wild are written in plain C (of course some are written in other languages, too, but I get the feeling that 80% of the daemons are written in plain C). Now I wonder why that is. Is this due to a pure historic UNIX background (like KISS) or for plain portability or reduction of bloat? What are the reasons to not use C++ or any "higher level" languages for things like daemons? Thanks in advance! Update 1: For me using C++ usually is more convenient because of the fact that I have objects which have getter and setter methods and such. Plain C's "context" objects can be a real pain at some point - especially when you are used to object oriented programming. Yes, I'm aware that C++ is a superset of C, and that C code is basically C++. But that's not the point. ;)

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  • Ruby: counters, counting and incrementing

    - by Shyam
    Hi, If you have seen my previous questions, you'd already know I am a big nuby when it comes to Ruby. So, I discovered this website which is intended for C programming, but I thought whatever one can do in C, must be possible in Ruby (and more readable too). The challenge is to print out a bunch of numbers. I discovered this nifty method .upto() and I used a block (and actually understanding its purpose). However, in IRb, I got some unexpected behavior. class MyCounter def run 1.upto(10) { |x| print x.to_s + " " } end end irb(main):033:0> q = MyCounter.new => #<MyCounter:0x5dca0> irb(main):034:0> q.run 1 2 3 4 5 6 7 8 9 10 => 1 I have no idea where the = 1 comes from :S Should I do this otherwise? I am expecting to have this result: 1 2 3 4 5 6 7 8 9 10 Thank you for your answers, comments and feedback!

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  • Is it OK to write code after [super dealloc]? (Objective-C)

    - by Richard J. Ross III
    I have a situation in my code, where I cannot clean up my classes objects without first calling [super dealloc]. It is something like this: // Baseclass.m @implmentation Baseclass ... -(void) dealloc { [self _removeAllData]; [aVariableThatBelongsToMe release]; [anotherVariableThatBelongsToMe release]; [super dealloc]; } ... @end This works great. My problem is, when I went to subclass this huge and nasty class (over 2000 lines of gross code), I ran into a problem: when I released my objects before calling [super dealloc] I had zombies running through the code that were activated when I called the [self _removeAllData] method. // Subclass.m @implementation Subclass ... -(void) deallloc { [super dealloc]; [someObjectUsedInTheRemoveAllDataMethod release]; } ... @end This works great, and It didn't require me to refactor any code. My question Is this: Is it safe for me to do this, or should I refactor my code? Or maybe autorelease the objects? I am programming for iPhone if that matters any.

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  • Help! I'm a Haskell Newbie

    - by Darknight
    I've only just dipped my toe in the world of Haskell as part of my journey of programming enlightenment (moving on from, procedural to OOP to concurrent to now functional). I've been trying an online Haskell Evaluator. However I'm now stuck on a problem: Create a simple function that gives the total sum of an array of numbers. In a procedural language this for me is easy enough (using recursion) (c#) : private int sum(ArrayList x, int i) { if (!(x.Count < i + 1)) { int t = 0; t = x.Item(i); t = sum(x, i + 1) + t; return t; } } All very fine however my failed attempt at Haskell was thus: let sum x = x+sum in map sum [1..10] this resulted in the following error (from that above mentioned website): Occurs check: cannot construct the infinite type: a = a -> t Please bear in mind I've only used Haskell for the last 30 minutes! I'm not looking simply for an answer but a more explanation of it. Thanks in advanced.

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  • Alter a function as a parameter before evaluating it in R?

    - by Shane
    Is there any way, given a function passed as a parameter, to alter its input parameter string before evaluating it? Here's pseudo-code for what I'm hoping to achieve: test.func <- function(a, b) { # here I want to alter the b expression before evaluating it: b(..., val1=a) } Given the function call passed to b, I want to add in a as another parameter without needing to always specify ... in the b call. So the output from this test.func call should be: test.func(a="a", b=paste(1, 2)) "1" "2" "a" Edit: Another way I could see doing something like this would be if I could assign the additional parameter within the scope of the parent function (again, as pseudo-code); in this case a would be within the scope of t1 and hence t2, but not globally assigned: t2 <- function(...) { paste(a=a, ...) } t1 <- function(a, b) { local( { a <<- a; b } ) } t1(a="a", b=t2(1, 2)) This is somewhat akin to currying in that I'm nesting the parameter within the function itself. Edit 2: Just to add one more comment to this: I realize that one related approach could be to use "prototype-based programming" such that things would be inherited (which could be achieved with the proto package). But I was hoping for a easier way to simply alter the input parameters before evaluating in R.

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  • Parallelize or vectorize all-against-all operation on a large number of matrices?

    - by reve_etrange
    I have approximately 5,000 matrices with the same number of rows and varying numbers of columns (20 x ~200). Each of these matrices must be compared against every other in a dynamic programming algorithm. In this question, I asked how to perform the comparison quickly and was given an excellent answer involving a 2D convolution. Serially, iteratively applying that method, like so list = who('data_matrix_prefix*') H = cell(numel(list),numel(list)); for i=1:numel(list) for j=1:numel(list) if i ~= j eval([ 'H{i,j} = compare(' char(list(i)) ',' char(list(j)) ');']); end end end is fast for small subsets of the data (e.g. for 9 matrices, 9*9 - 9 = 72 calls are made in ~1 s). However, operating on all the data requires almost 25 million calls. I have also tried using deal() to make a cell array composed entirely of the next element in data, so I could use cellfun() in a single loop: # who(), load() and struct2cell() calls place k data matrices in a 1D cell array called data. nextData = cell(k,1); for i=1:k [nextData{:}] = deal(data{i}); H{:,i} = cellfun(@compare,data,nextData,'UniformOutput',false); end Unfortunately, this is not really any faster, because all the time is in compare(). Both of these code examples seem ill-suited for parallelization. I'm having trouble figuring out how to make my variables sliced. compare() is totally vectorized; it uses matrix multiplication and conv2() exclusively (I am under the impression that all of these operations, including the cellfun(), should be multithreaded in MATLAB?). Does anyone see a (explicitly) parallelized solution or better vectorization of the problem?

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  • SYN receives RST,ACK very frequently

    - by user1289508
    Hi Socket Programming experts, I am writing a proxy server on Linux for SQL Database server running on Windows. The proxy is coded using bsd sockets and in C, and it is working just fine. When I use a database client (written in JAVA, and running on a Linux box) to fire queries (with a concurrency of 100 or more) directly to the Database server, not experiencing connection resets. But through my proxy I am experiencing many connection resets. Digging deeper I came to know that connection from 'DB client' to 'Proxy' always succeeds but when the 'Proxy' tries to connect to the DB server the connection fails, due to the SYN packet getting RST,ACK. That was to give some background. The question is : Why does sometimes SYN receives RST,ACK? 'DB client(linux)' to 'Server(windows)' ---- Works fine 'DB client(linux) to 'Proxy(Linux)' to 'Server(windows)' ----- problematic I am aware that this can happen in "connection refused" case but this definitely is not that one. SYN flooding might be another scenario, but that does not explain fine behavior while firing to Server directly. I am suspecting some socket option setting may be required, that the client does before connecting and my proxy does not. Please put some light on this. Any help (links or pointers) is most appreciated. Additional info: Wrote a C client that does concurrent connections, which takes concurrency as an argument. Here are my observations: - At 5000 concurrency and above, some connects failed with 'connection refused'. - Below 2000, it works fine. But the actual problem is observed even at a concurrency of 100 or more. Note: The problem is time dependent sometimes it never comes at all and sometimes it is very frequent and DB client (directly to server) works fine at all times .

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  • What is the best Networking implementation for my application?

    - by CaptainPhil
    I am in the planning phases of a project for myself, it is to be a single and multi-player card game. I would like to track statistics for each person such as world rankings etc... My problem is I do not know the best approach for the client - server architecture and programming. My original goal was to program everything in C# as I want to get proficient in that language. My original idea was to have a back-end database and a back end server run on some sort of hosting on the internet, however that seems costly for such a small project that may or may not make any money. I have tried looking into cloud services however I am unfamiliar with the technology, and I am not sure I can make them suit my needs, especially since most like Google's cloud wants you to use their coding architecture from what I understand. Finally my last problem is that I would like an architecture that can be used for different languages so that I can port it from PC to IPhone, Xbox etc... So does anyone have any advice on the best architecture and language to do this in? Am I worrying about architecture and back-end costs to much and should just concentrate on getting the game running any which way?

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  • Finding k elements of length-n list that sum to less than t in O(nlogk) time

    - by tresbot
    This is from Programming Pearls ed. 2, Column 2, Problem 8: Given a set of n real numbers, a real number t, and an integer k, how quickly can you determine whether there exists a k-element subset of the set that sums to at most t? One easy solution is to sort and sum the first k elements, which is our best hope to find such a sum. However, in the solutions section Bentley alludes to a solution that takes nlog(k) time, though he gives no hints for how to find it. I've been struggling with this; one thought I had was to go through the list and add all the elements less than t/k (in O(n) time); say there are m1 < k such elements, and they sum to s1 < t. Then we are left needing k - m1 elements, so we can scan through the list again in O(n) time looking for all elements less than (t - s1)/(k - m1). Add in again, to get s2 and m2, then again if m2 < k, look for all elements less than (t - s2)/(k - m2). So: def kSubsetSumUnderT(inList, k, t): outList = [] s = 0 m = 0 while len(outList) < k: toJoin = [i for i in inList where i < (t - s)/(k - m)] if len(toJoin): if len(toJoin) >= k - m: toJoin.sort() if(s0 + sum(toJoin[0:(k - m - 1)]) < t: return True return False outList = outList + toJoin s += sum(toJoin) m += len(toJoin) else: return False My intuition is that this might be the O(nlog(k)) algorithm, but I am having a hard time proving it to myself. Thoughts?

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  • How to troubleshoot a 'System.Management.Automation.CmdletInvocationException'

    - by JamesD
    Does anyone know how best to determine the specific underlying cause of this exception? Consider a WCF service that is supposed to use Powershell 2.0 remoting to execute MSBuild on remote machines. In both cases the scripting environments are being called in-process (via C# for Powershell and via Powershell for MSBuild), rather than 'shelling-out' - this was a specific design decision to avoid command-line hell as well as to enable passing actual objects into the Powershell script. The Powershell script that calls MSBuild is shown below: function Run-MSBuild { [System.Reflection.Assembly]::LoadWithPartialName("Microsoft.Build.Engine") $engine = New-Object Microsoft.Build.BuildEngine.Engine $engine.BinPath = "C:\Windows\Microsoft.NET\Framework\v3.5" $project = New-Object Microsoft.Build.BuildEngine.Project($engine, "3.5") $project.Load("deploy.targets") $project.InitialTargets = "DoStuff" # # Set some initial Properties & Items # # Optionally setup some loggers (have also tried it without any loggers) $consoleLogger = New-Object Microsoft.Build.BuildEngine.ConsoleLogger $engine.RegisterLogger($consoleLogger) $fileLogger = New-Object Microsoft.Build.BuildEngine.FileLogger $fileLogger.Parameters = "verbosity=diagnostic" $engine.RegisterLogger($fileLogger) # Run the build - this is the line that throws a CmdletInvocationException $result = $project.Build() $engine.Shutdown() } When running the above script from a PS command prompt it all works fine. However, as soon as the script is executed from C# it fails with the above exception. The C# code being used to call Powershell is shown below (remoting functionality removed for simplicity's sake): // Build the DTO object that will be passed to Powershell dto = SetupDTO() RunspaceConfiguration runspaceConfig = RunspaceConfiguration.Create(); using (Runspace runspace = RunspaceFactory.CreateRunspace(runspaceConfig)) { runspace.Open(); IList errors; using (var scriptInvoker = new RunspaceInvoke(runspace)) { // The Powershell script lives in a file that gets compiled as an embedded resource TextReader tr = new StreamReader(Assembly.GetExecutingAssembly().GetManifestResourceStream("MyScriptResource")); string script = tr.ReadToEnd(); // Load the script into the Runspace scriptInvoker.Invoke(script); // Call the function defined in the script, passing the DTO as an input object var psResults = scriptInvoker.Invoke("$input | Run-MSBuild", dto, out errors); } } Assuming that the issue was related to MSBuild outputting something that the Powershell runspace can't cope with, I have also tried the following variations to the second .Invoke() call: var psResults = scriptInvoker.Invoke("$input | Run-MSBuild | Out-String", dto, out errors); var psResults = scriptInvoker.Invoke("$input | Run-MSBuild | Out-Null", dto, out errors); var psResults = scriptInvoker.Invoke("Run-MSBuild | Out-String"); var psResults = scriptInvoker.Invoke("Run-MSBuild | Out-String"); var psResults = scriptInvoker.Invoke("Run-MSBuild | Out-Null"); I've also looked at using a custom PSHost (based on this sample: http://blogs.msdn.com/daiken/archive/2007/06/22/hosting-windows-powershell-sample-code.aspx), but during debugging I was unable to see any 'interesting' calls to it being made. Do the great and the good of Stackoverflow have any insight that might save my sanity?

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  • Controlled execution of computationally expensive tasks

    - by Sergio
    Say you have an application where a user is typing some text and as she types you'd want to perform some expensive computations in the background (related to the text that is being typed). Although you would like to do lots of things, your main priority is that the system responsiveness stay at acceptable levels so the user doesn't notice such a heavy load. Is there a way (ideally platform/language independent) to control what algorithms should be executed in the background based on the system load and responsiveness?

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  • Is it possible to make an OS in python?

    - by None
    I was just wondering if it was possible to make an operating system in python. Nothing fancy. Maybe not even a "real" operating system with a kernel and all. Just a python program that is run when someone inserts the disc containing it that will make a fullscreen display on top of the installed os.

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  • Fatal IO error 0 (Success) on X server

    - by Ori Pessach
    What does the error "Fatal IO error 0 (Success) on X server" mean? The error is produced when an X client tries to call XvCreateImage(), and it results in the client terminating. X.0.log shows the following version information: X.Org X Server 1.6.4 Release Date: 2009-9-27 X Protocol Version 11, Revision 0 Build Operating System: Linux 2.6.24-23-server i686 Ubuntu Current Operating System: Linux ori-laptop 2.6.31-17-generic #54-Ubuntu SMP Thu Dec 10 16:20:31 UTC 2009 i686 Kernel command line: BOOT_IMAGE=/boot/vmlinuz-2.6.31-17-generic root=UUID=df637de9-47ed-4453-9393-67e2e2ffaa2f ro quiet splas

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  • Problem running latex from FastCGI

    - by Engwan
    I have a program which does a system call: latex somefile.latex This runs ok, when I type it directly in the command line, or when i invoke the program via CGI. But when it is using FastCGI, the system call returns: This is pdfTeX, Version 3.1415926-1.40.10 (TeX Live 2009) ---! Must increase the hyph_size (Fatal format file error; I'm stymied) I already tried to increase the hyph_size but still no effect.

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  • System.MissingMemberException was unhandled by user code

    - by AmRoSH
    I'm using this code: Dim VehiclesTable1 = dsVehicleList.Tables(0) Dim VT1 = (From d In VehiclesTable1.AsEnumerable _ Select VehicleTypeName = d.Item("VehicleTypeName") _ , VTypeID = d.Item("VTypeID") _ , ImageURL = d.Item("ImageURL") _ , DailyRate = d.Item("DailyRate") _ , RateID = d.Item("RateID")).Distinct its linq to dataset and I Take Data on THis Rotator: <telerik:RadRotator ID="RadRotatorVehicleType" runat="server" Width="620px" Height="145" ItemWidth="155" ItemHeight="145" ScrollDirection="Left" FrameDuration="1" RotatorType="Buttons"> <ItemTemplate> <div style="text-align: center; cursor: pointer; width: 150px"> <asp:Image ID="ImageVehicleType" runat="server" Width="150" ImageUrl='<%# Container.DataItem("ImageURL") %>' /> <asp:Label ID="lblVehicleType" runat="server" Text='<%# Container.DataItem("VehicleTypeName") %>' Font-Bold="true"></asp:Label> <br /> <asp:Label ID="lblDailyRate" runat="server" Text='<%# Container.DataItem("DailyRate") %>' Visible="False"></asp:Label> <input id="HiddenVehicleTypeID" type="hidden" value='<%# Container.DataItem("VTypeID") %>' name="HiddenVehicleTypeID" runat="server" /> <input id="HiddenRateID" type="hidden" value='<%# Container.DataItem("RateID") %>' name="HiddenRateID" runat="server" /> </div> </ItemTemplate> <ControlButtons LeftButtonID="img_left" RightButtonID="img_right" /> </telerik:RadRotator> and I got this Exception: No default member found for type 'VB$AnonymousType_0(Of Object,Object,Object,Object,Object)'. Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code. Exception Details: System.MissingMemberException: No default member found for type 'VB$AnonymousType_0(Of Object,Object,Object,Object,Object)'. I don't know whats up ? Any help please. Thanks for who tried to solve this but I got solution: using '<%# DataBinder.Eval(Container.DataItem,"ImageURL") %>' instead of '<%# Container.DataItem("RateID") %>' Thanks,

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  • Detecting abuse for post rating system

    - by Steven smethurst
    I am using a wordpress plugin called "GD Star Rating" to allow my users to vote on stories that I post to one of my websites. http://everydayfiction.com/ Recently we have been having a lot of abuse of the system. Stories that have obviously been voted up artificially. "GD Star Rating" creates some detailed logs when a user votes on a story. Including; IP, Time of vote, and user_adgent, ect.. For example this story has 181 votes with an average of 5.7 http://www.everydayfiction.com/snowman-by-shaun-simon/ Most other stories only get around ~40 votes each day. At first I thought that the story got on to a social bookmarking site Digg, Stumbleupon ect... but after checking the logs I found that this story is getting the same amount of traffic that a normal story gets ~2k-3k. I checked if all the votes for this perpendicular story where coming from a the same IP address. I could see this happening if a user was at a school's computer lab using all their lab computers to vote up this story. Not one duplicate IP address in the log for this story. SELECT ip, COUNT(*) as count FROM wp_gdsr_votes_log WHERE id=3932 GROUP BY (ip ) ORDER BY count DESC Next I thought that a use might be using a proxy to vote up a story. I checked this by grouping all the browser user_agent together to see if there a single browser voting in a perpendicular way. At most 7 users where using a similar browser but voted sporadically (1-5), no evidence of wrong doing. SELECT user_agent, COUNT(*) as count FROM wp_gdsr_votes_log WHERE id=3932 GROUP BY ( user_agent) ORDER BY count DESC I check was to see if all the votes came in at a once. Maybe someone has a really interesting bot that can change the user_adgent and uses proxies, ect... At most 5 votes came with in 2 mins of each other. It doesn't seem to be any regularity on how people vote (IE a 5 vote does not come in once a min) SELECT * FROM wp_gdsr_votes_log WHERE id =3932 AND vote=5 ORDER BY wp_gdsr_votes_log.voted DESC The obvious solution to this problem is to force people to login before they are allowed to vote. But I would prefer to not have to go down that route unless it is absolutely necessary. I'm looking for suggestions on things to test for to detect the abuse.

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  • Which is more robust and scalable method?

    - by Dhruv Arya
    I am implementing a distributed chat system, in this system we have the following options : Make the client and server running at each node run as separate threads. The server acting as the receiver will be running as the daemon thread and the client taking the user input as a normal thread. Fork two processes one for the client and one for the server. I am not able to reason out with which one to proceed. Any insight would be great !

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  • how to store data crawled from website

    - by Richard
    I want to crawl a website and store the content on my computer for later analysis. However my OS file system has a limit on the number of sub directories, meaning storing the original folder structure is not going to work. Suggestions? Map the URL to some filename so can store flatly? Or just shove it in a database like sqlite to avoid file system limitations?

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  • No more memory available in Mathematica, Fit the parameters of system of differential equation

    - by user1058051
    I encountered a memory problem in Mathematica, when I tried to process my experimental data. It's a system of two differential equations and I need to find most suitable parameters. Unfortunately I am not a Pro in Mathematica, so the program used a lot of memory, when the parameter epsilon is more than 0.4. When it less than 0.4, the program work properly. The command 'historylength = 0' and attempts to reduce the Accuracy Goal and WorkingPrecision didn`t help. I can't use ' clear Cache ', because there isnt a circle. I'm trying to understand what mistakes I made, and how I may limit the memory usage. I have already bought extra-RAM, now its 4GB, and now I haven't free memory-slots in motherboard Remove["Global`*"]; T=13200; L = 0.085; e = 0.41; v = 0.000557197; q = 0.1618; C0 = 0.0256; R = 0.00075; data = {{L,600,0.141124587},{L,1200,0.254134509},{L,1800,0.342888644}, {L,2400,0.424476295},{L,3600,0.562844542},{L,4800,0.657111356}, {L,6000,0.75137817},{L,7200,0.815876516},{L,8430,0.879823594}, {L,9000,0.900771775},{L,13200,1}}; model[(De_)?NumberQ, (Kf_)?NumberQ, (Y_)?NumberQ] := model[De, Kf, Y] = yeld /.Last[Last[ NDSolve[{ v (Ci^(1,0))[z,t]+(Ci^(0,1))[z,t]== -((3 (1-e) Kf (Ci[z,t]-C0))/ (R e (1-(R Kf (1-R/r[z,t]))/De))), (r^(0,1))[z,t]== (R^2 Kf (Ci[z,t]-C0))/ (q r[z,t]^2 (1-(R Kf (1-R/r[z,t]))/De)), (yeld^(0,1))[z,t]== Y*(v e Ci[z,t])/(L q (1-e)), r[z,0]==R, Ci[z,0]==0, Ci[0,t]==0, yeld[z,0]==0}, {r[z,t],Ci[z,t],yeld},{z,0,L},{t,0,T}]]] fit = FindFit[data, {model[De, Kf, Y][z, t], {Y > 0.97, Y < 1.03, Kf > 10^-6, Kf < 10^-4, De > 10^-13, De < 10^-9}}, {{De,7*10^-13}, {Kf, 10^-5}, {Y, 1}}, {z, t}, Method -> NMinimize] data = {{600,0.141124587},{1200,0.254134509},{1800,0.342888644}, {2400,0.424476295},{3600,0.562844542},{4800,0.657111356}, {6000,0.75137817},{7200,0.815876516},{8430,0.879823594}, {9000,0.900771775},{13200,1}}; YYY = model[ De /. fit[[1]], Kf /. fit[[2]], Y /. fit[[3]]]; Show[Plot[Evaluate[YYY[L,t]],{t,0,T},PlotRange->All], ListPlot[data,PlotStyle->Directive[PointSize[Medium],Red]]] the link on the .nb file http://www.4shared.com/folder/249TSjlz/_online.html

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  • OTRS upgrade 3.0 to 3.1 fails

    - by Valentin0S
    Today I've started upgrading OTRS from version 2.3 to 2.4 , 2.4 to 3.0 and 3.0 to 3.1. Everything went smoothly except the upgrade from 3.0 to 3.1 OTRS provides a few perl scripts which make the upgrade easier. I've used these scripts for each upgrade step. The upgrade from 3.0 to 3.1 fails at the following after using the upgrade script. scripts/DBUpdate-to-3.1.pl The error is : root@tickets:/opt/otrs# su - otrs $ scripts/DBUpdate-to-3.1.pl Migration started... Step 1 of 24: Refresh configuration cache... If you see warnings about 'Subroutine Load redefined', that's fine, no need to worry! Subroutine Load redefined at /opt/otrs/Kernel/Config/Files/ZZZAAuto.pm line 5. Subroutine Load redefined at /opt/otrs/Kernel/Config/Files/ZZZAuto.pm line 4. done. Step 2 of 24: Check framework version... done. Step 3 of 24: Creating DynamicField tables (if necessary)... done. DBD::mysql::db do failed: Cannot add or update a child row: a foreign key constraint fails (`pp_otrs`.`dynamic_field`, CONSTRAINT `FK_dynamic_field_create_by_id` FOREIGN KEY (`create_by`) REFERENCES `users` (`id`)) at /opt/otrs-3.1.10/Kernel/System/DB.pm line 478. ERROR: OTRS-DBUpdate-to-3.1-10 Perl: 5.14.2 OS: linux Time: Wed Sep 5 15:36:20 2012 Message: Cannot add or update a child row: a foreign key constraint fails (`pp_otrs`.`dynamic_field`, CONSTRAINT `FK_dynamic_field_create_by_id` FOREIGN KEY (`create_by`) REFERENCES `users` (`id`)), SQL: 'INSERT INTO dynamic_field (name, label, field_order, field_type, object_type, config, valid_id, create_time, create_by, change_time, change_by) VALUES (?, ?, ?, 'Text', 'Ticket', '--- {} ', 1, '2012-09-05 15:36:20' , 1, '2012-09-05 15:36:20' , 1)' Traceback (20405): Module: main::_DynamicFieldCreation (v1.85) Line: 466 Module: scripts/DBUpdate-to-3.1.pl (v1.85) Line: 95 Could not create new DynamicField TicketFreeKey1 at scripts/DBUpdate-to-3.1.pl line 477. Step 4 of 24: Create new dynamic fields for free fields (text, key, date)... $ Did anyone else face the same issue? Thanks in advance

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  • How to find out which program a default beep is coming from in Windows 7?

    - by leeand00
    There's a "default beep" (as defined in System Sounds) that emanates from my computer every so often. It kind of goes like this (where each number is a "default beep" sound): 1, 2, 3, 4, 5. So there's a distinct pattern to it. I thought I had this figured out a way to figure out what was happening by going to Control Panel-Ease of Access-Ease of Access Center-Replace sounds with visual cues But that just isn't the case. Whichever window I click on, that one displays the visual queue when this happens. It's driving me crazy, and I can't figure out which program is causing this. Update: it appears to only happen on one user profile on the computer...does that help? Update 2: Discovered that this sound was coming from a utility on my laptop called ASUS NB Probe; I'm certain that it is emanating from this program because the error message displayed by it changes in sync with the sound playing. Apparently the S.M.A.R.T. feature of my hard drive was reporting an issue. It displays the issue for a brief second and then makes it disappear, I'll have to keep watching it to see what it says, but I believe is says something about a read. I have an external hdd connected with eSATA to a container of sorts (BlacX) that you can plug two hdds into. I have one hdd attached and it's a Western Digital WD1001FALS - 00E8B0 Thanks again! Now I'm off to go around the Internet and report on this...since I posted it so many places!

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  • PC only boots from Linux-based media and won't boot from DOS-based media

    - by Xolstice
    I have this problem where the PC only seems to boot from a floppy disk or CD if it was created as a Linux-based bootable media. If it was created as a DOS-based bootable media the system just freezes at the starting point of the boot process. I originally asked this under question 139515 for CD booting only, and based on the given answers, I was under the impression the problem was with the CD-ROM drive; however, I have since installed a newly purchased CD-ROM drive and the same freezing occurs. This then made me try the DOS bootable floppy disk approach and I was quite surprised that it exhibited the same freezing problem. I then tried try a Linux bootable floppy and everything booted from it without any issues. As I mentioned in my original question, the PC was booting just fine from the DOS-based bootable CD, and then it suddenly decides to pull this freezing stunt. I can't remember if I changed anything in the BIOS settings that may I have caused the problem, but I am wondering if that could be the case - it is currently using the Award Module BIOS v4.60PGMA. Can anyone help?

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