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  • CS Master's Degree Project vs. Thesis options

    - by Nwosh
    I'm doing a master's degree in computer science, and I'm currently at the point where I have to decide between the thesis and non-thesis options offered by my university. The thesis option was my first choice, it entails taking less courses but tends to take more time doing your thesis. The non-thesis option involves taking more coursework, taking a comprehensive exam, and doing a project in one semester with a faculty member. I'd like to pursue a PhD degree eventually (although not right away, I want to get some years of professional experience first), and I heard that having demonstrated the ability to work on a thesis helps a lot with admission (like: not doing thesis raises questions and suggests not being interested in research) and that the experience itself is very good. At the same time, almost everyone I know who did a thesis at my university took a long time (2-3 years), in theory it could be done in 1.5 years. I'm a part time student and I don't really want to spend so much time just getting a master's degree, I could still publish a few papers while working on the project option and I'd be done in a year or so, additionally, I heard having a master's degree with a project and more coursework is more desirable for the industry. So, when applying for a PhD degree in CS at some of the better universities, would the time spent working on the master's thesis help in getting me accepted? Or should I opt for the non-thesis option and hope that the extra coursework and publishing some papers would make up for not working on a thesis?

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  • F# and .Net versions

    - by rwallace
    I'm writing a program in F# at the moment, which I specified in the Visual Studio project setup to target .Net 3.5, this being the highest offered, on the theory that I might as well get the best available. Then I tried just now running the compiled program on an XP box, not expecting it to work, but just to see what would happen. Unsurprisingly I just got an error message demanding an appropriate version of the framework, but surprisingly it wasn't 3.5 it demanded, but 2.0.50727. An additional puzzle is the version of MSBuild I'm using to compile the release version of the program, which I found in the framework 3.5 directory but claims to be framework 2.0 and build engine 3.5. I just guessed it was the right version of MSBuild to use because it seemed to correspond with the highest framework version F# seems to be able to target, but should I be using a different version? Anyone have any idea what's going on? C:\Windows>dir/s msbuild.exe Volume in drive C is OS Volume Serial Number is 0422-C2D0 Directory of C:\Windows\Microsoft.NET\Framework\v2.0.50727 27/07/2008 19:03 69,632 MSBuild.exe 1 File(s) 69,632 bytes Directory of C:\Windows\Microsoft.NET\Framework\v3.5 29/07/2008 23:40 91,136 MSBuild.exe 1 File(s) 91,136 bytes Directory of C:\Windows\Microsoft.NET\Framework\v4.0.30319 18/03/2010 16:47 132,944 MSBuild.exe 1 File(s) 132,944 bytes Directory of C:\Windows\winsxs\x86_msbuild_b03f5f7f11d50a3a_6.0.6000.16386_none_815e96e1b0e084be 20/10/2006 02:14 69,632 MSBuild.exe 1 File(s) 69,632 bytes Directory of C:\Windows\winsxs\x86_msbuild_b03f5f7f11d50a3a_6.0.6000.16720_none_81591d45b0e55432 27/07/2008 19:00 69,632 MSBuild.exe 1 File(s) 69,632 bytes Directory of C:\Windows\winsxs\x86_msbuild_b03f5f7f11d50a3a_6.0.6000.20883_none_6a9133e9ca879925 27/07/2008 18:55 69,632 MSBuild.exe 1 File(s) 69,632 bytes C:\Windows>cd Microsoft.NET\Framework\v3.5 C:\Windows\Microsoft.NET\Framework\v3.5>msbuild /ver Microsoft (R) Build Engine Version 3.5.30729.1 [Microsoft .NET Framework, Version 2.0.50727.3053] Copyright (C) Microsoft Corporation 2007. All rights reserved. 3.5.30729.1

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  • Getting browser to make an AJAX call ASAP, while page is still loading

    - by Chris
    I'm looking for tips on how to get the browser to kick off an AJAX call as soon as possible into processing a web page, ideally before the page is fully downloaded. Here's my approximate motivation: I have a web page that takes, say, 5 seconds to load. It calls a web service that takes, say, 10 seconds to load. If loading the page and calling the web service happened sequentially, the user would have to wait 15 seconds to see all the information. However, if I can get the web service call started before the 5 second page load is complete, then at least some of the work can happened in parallel. Ideally I'd like as much of the work to happen in parallel as possible. My initial theory was that I should place the AJAX-calling javascript as high up as possible in the web page HTML source (being mindful of putting it after the jquery.js include, because I'm making the call using jquery ajax). I'm also being mindful not to wrap the AJAX call in a jquery ready event handler. (I mention this because ready events are popular in a lot of jquery example code.) However, the AJAX call still doesn't seem to get kicked off as early as I'm hoping (at least as judged by the Google Chrome "Timeline" feature), so I'm wondering what other considerations apply. One thing that might potentially be detrimental is that the AJAX call is back to the same web server that's serving the original web page, so I might be in danger of hitting a browser limit on the # of HTTP connections back to that one machine? (The HTML page loads a number of images, css files, etc..)

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  • Flash movies in inactive browser tabs pause or don't execute in real time

    - by ZenBlender
    I'm noticing some unexpected behavior. Some time in the last few months, a change in either Firefox, the Flash player, or both, has made it so that Flash movies that are in inactive browser tabs no longer execute in real time. They appear to still execute, but only in bursts, and not in a predictable way. This is a problem because I develop a Flash-based (Actionscript 2.0, Flash CS3) multiplayer game that maintains a network connection and allows players to chat, etc. Many of our players complain about Firefox crashing while playing the game. I have noticed it too, not too frequently, but it crashes several times a week. (Firefox crashes, I do not get a message from Flash player that indicates an infinite loop or problem in my code) My theory is that this new behavior is causing crashes when there is a lot of activity in my game, leading to lots of unhandled network traffic for my game getting buffered before Firefox/Flash will give it a chance to execute. Maybe this leads to a buffer overflow or missing packets, and as a result, something crashes. At times I will switch back to the tab that is running my game and discover a display bug, which looks as though Flash has simply failed to execute something that it was supposed to. I would assume this new behavior is on purpose, for example to prevent all the Flash-based advertisements in inactive tabs from executing and therefore killing performance. In a quick test on Chrome (5.0.342.9 beta), this "pausing" of Flash seems to be there as well, but somehow it seems much less of a problem. My users have only complained about Firefox crashing, not other browsers. My machine: Windows 7 x64 Firefox 3.6.3 Flash Player 10.1.50.426 My game: triplejack.com Any ideas? Ideally I'd like to disable this behavior for my Flash game so it can execute in real time even when in an inactive tab. Thanks for any help!

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  • Optimized Publish/Subcribe JMS Broker Cluster and Conflicting Posts on StackOverFlow for the Answer

    - by Gene
    Hi, I am looking to build a publish/subscribe distributed messaging framework that can manage huge volumes of message traffic with some intelligence at the broker level. I don't know if there's a topology that describes this, but this is the model I'm going after: EXAMPLE MODEL A A) There are two running message brokers (ideally all on localhost if possible, for easier demo-ing) : Broker-A Broker-B B) Each broker will have 2 listeners and 1 publisher. Example Figure [subscriber A1, subscriber A2, publisher A1] <-- BrokerA <-- BrokerB <-- [publisher B1, subscriber B1, subscriber B2] IF a message-X is published to broker A and there no subscribers for it among the listeners on Broker-B (via criteria in Message Selectors or Broker routing rules), then that message-X will never be published to Broker-B. ELSE, broker A will publish the message to broker B, where one of the broker B listeners/subscribers/services is expecting that message based on the subscription criteria. Is Clustering the Correct Approach? At first, I concluded that the "Broker Clustering" concept is what I needed to support this. However, as I have come to understand it, the typical use of clustering entails either: message redundancy across all brokers ... or Competing Consumers pattern ... and neither of these satisfy the requirement in the EXAMPLE MODEL A. What is the Correct Approach? My question is, does anyone know of a JMS implementation that supports the model I described? I scanned through all the stackoverflow post titles for the search: JMS and Cluster. I found these two informative, but seemingly conflicting posts: Says the EXAMPLE MODEL A is/should-be implicitly supported: http://stackoverflow.com/questions/2255816/jms-consumer-with-activemq-network-of-brokers " this means you pick a broker, connect to it, and let the broker network sort it out amongst themselves. In theory." Says the EXAMPLE MODEL A IS NOT suported: http://stackoverflow.com/questions/2017520/how-does-a-jms-topic-subscriber-in-a-clustered-application-server-recieve-message "All the instances of PropertiesSubscriber running on different app servers WILL get that message." Any suggestions would be greatly appreciated. Thanks very much for reading my post, Gene

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  • Java Playing Cards Game Framework

    - by isme
    My friends and I at uni love playing Shithead into the wee hours. But soon we graduate and will leave town, so probably won't get together for a game for a while. I want to develop a Java app we can use to play Shithead and our other favorites over a network. An app like this already exists, but is ugly, buggy and does not support our house rules. The source is available, but is such a mess that I would really rather start from scratch than try to refactor it! Building my game using some standard playing card api or framework, if such a thing exists, would be better than starting from scratch. The answer to a similar SO question was to use the JPC-API, which allegedly provides basic playing card services and rendering. But this Sourceforge project currently makes available no files or source code! Is there an alternative, or somewhere else to find this framework? Soon I will need help with the following as well: Lobby services (finding other players) Gaming network protocol (to communicate moves between players) Gaming theory (to write the computer opponent) Winning condition detection Game UI development

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  • Managing common components with Fossil CVS

    - by Larry Lustig
    I'm a Fossil (and CVS configuration novice) attempting to create and manage a set of distributed Fossil repositories for a Delphi project. I have the following directory tree: Projects Some Project Delphi Components LookupListView Some Client Some Project For Client Some Other Project For Client Source Code Project Resources Project Database I am setting up Fossil version control in order to version and share Projects\Some Client\Some Other Project For Client\Source Code, which contains Delphi 2010 source for a database project. This project makes use of Projects\Delphi Components\LookupListView which is a Delphi component. I need this code to be included in the versioning system for my project. I will, in theory, need to include it in other Fossil repositories in the future, as well. If I create my Fossil repository at the Source Code or Some Other Project For Client level, I cannot add any code above that level to my repository. What is the proper way to deal with this? The two solutions that occur to me are 1) Creating a separate repository for LookupListView and make sure that everyone who uses a repository for a project that references it "knows" that they must also get the current version of this project as well. This seems to defeat the purpose of being able to obtain a complete, current version of the project with a single checkout. The problem is magnified because there are other common component dependencies in this project. 2) Establishing my Fossil repository in the Projects directory, so I can check in files from various subfolders. This seems to me to involve an awful lot of extra path-typing when doing adds, and also to impose my directory structure (Some Client\Some Other Project For Client\Source) on the other users of the repository -- in this case, the actual client. Any suggestions appreciated.

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  • Where can I find clear examples of MVC?

    - by Tom
    I've read a couple of things about MVCs but I still don't understand when they should be used and when they shouldn't be used. I am looking for clear examples that say things like "if you're developing this then you should use MVC, like this" and "if you're developing this, you shouldn't use MVC." Most of the examples I've seen rely on complex frameworks which have already implemented everything and you have to learn the framework and use it a lot to understand what's really happening. To many programmers, phrasings such as "UI business logic" sound like marketing terms — for example, the words "Instead the View binds directly to a Presentation Model" are used in this post. I am aware of the dangers that may lurk in the shadows as MVC is a concept and everyone feels like they know it best, yet nobody really knows exactly how to use it because there may be a lot of variables involved and everyone is allowed to have a different perspective on how to dissect a project into the Model, the View and the Controller. There is a lot of theory out there but very few clear examples. What I'm looking for are not "the best" ways of doing it so this should not be considered as subjective; I'm looking for different simple implementations that would allow me to decide on my own which are the best approaches. Succinctly: What are good on-line resources that present pro and con arguments to using MVC in various situations and provide clear examples to help the reader understand the concept?

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  • Subdomain on different host

    - by mattsmith321
    Hi everyone! I'm trying to host a subdomain for my site with a different hosting company and I'm running into issues on how to set it up. Here are the specifics: - Domain is registered with GoDaddy. - Nameservers are pointing to DiscountASP.net where ASP.NET app has been happily running for couple of years. - Would like blog.mydomain.com to point to my account with DreamHost.com to take advantage of their LAMP stack. I have added blog.mydomain.com to DreamHost (after adding mydomain.com) via their control panel. I thought I would be able to add a subdomain entry on GoDaddy to point to DreamHost, but all they allow is blog.mydomain.com = new url. In theory I could just take our .biz or .net domain and host it on DreamHost but was hoping I could do it all with a subdomain. So, to summarize I'd like to know if what I want to do is feasible and if so, how do I go about it (given the constraints of GoDaddy, DiscountASP, & DreamHost). Thanks, Matt

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  • Evolutionary Algorithms: Optimal Repopulation Breakdowns

    - by Brian MacKay
    It's really all in the title, but here's a breakdown for anyone who is interested in Evolutionary Algorithms: In an EA, the basic premise is that you randomly generate a certain number of organisms (which are really just sets of parameters), run them against a problem, and then let the top performers survive. You then repopulate with a combination of crossbreeds of the survivors, mutations of the survivors, and also a certain number of new random organisms. Do that several thousand times, and efficient organisms arise. Some people also do things like introduce multiple "islands" of organisms, which are seperate populations that are allowed to crossbreed once in awhile. So, my question is: what are the optimal repopulation percentages? I have been keeping the top 10% performers, and repopulating with 30% crossbreeds and 30% mutations. The remaining 30% is for new organisms. I have also tried out the multiple island theory, and I'm interested in your results on that as well. It is not lost on me that this is exactly the type of problem an EA could solve. Are you aware of anyone trying that? Thanks in advance!

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  • need help passing multiple variables from foreach loop to test in switch case statement

    - by Brad
    $list_of_groups = array("FACULTY","STAFF"); foreach ($list_of_groups as $i => $group) { $user_in_group = $adldap->user_ingroup($username,$group); print "<h2>Group: ".$group." user in group? ".$user_in_group."</h2>"; // if 1, means yes } Need to print run the appropriate function based on what returns true. There are user's that are members of both FACULTY and STAFF groups, so I want to check for those users and display the appropriate content for them. So if the user is both faculty and staff, then display this, if they are only of staff, display that, same for faculty, might not make sense, but I will write out some code "in theory" that will help you understand what I am trying to do switch(Get group membership of user) { case "FACULTY": print "Faculty group member"; break; case "STAFF": print "Staff group member"; break; case "FACULTY and STAFF": print "Member of both faculty and staff"; break; } I am unsure on how it will check if they are members of both groups and run that thru the case statement to display the appropriate message. The foreach look currently runs thru every group the user belongs to, prints out the ones from the $list_of_groups and the number 1 to the right of it, signifying they belong to it. The problem I have is trying to use that information to run thru the case statement, I am unsure of how to go about that. This is what it prints out for the user currently passed thru the foreach loop: Group: FACULTY user in group? 1 Group: STAFF user in group? 1 Any help is appreciated.

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  • Autodetect Presence of CSV Headers in a File

    - by banzaimonkey
    Short question: How do I automatically detect whether a CSV file has headers in the first row? Details: I've written a small CSV parsing engine that places the data into an object that I can access as (approximately) an in-memory database. The original code was written to parse third-party CSV with a predictable format, but I'd like to be able to use this code more generally. I'm trying to figure out a reliable way to automatically detect the presence of CSV headers, so the script can decide whether to use the first row of the CSV file as keys / column names or start parsing data immediately. Since all I need is a boolean test, I could easily specify an argument after inspecting the CSV file myself, but I'd rather not have to (go go automation). I imagine I'd have to parse the first 3 to ? rows of the CSV file and look for a pattern of some sort to compare against the headers. I'm having nightmares of three particularly bad cases in which: The headers include numeric data for some reason The first few rows (or large portions of the CSV) are null There headers and data look too similar to tell them apart If I can get a "best guess" and have the parser fail with an error or spit out a warning if it can't decide, that's OK. If this is something that's going to be tremendously expensive in terms of time or computation (and take more time than it's supposed to save me) I'll happily scrap the idea and go back to working on "important things". I'm working with PHP, but this strikes me as more of an algorithmic / computational question than something that's implementation-specific. If there's a simple algorithm I can use, great. If you can point me to some relevant theory / discussion, that'd be great, too. If there's a giant library that does natural language processing or 300 different kinds of parsing, I'm not interested.

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  • SIMPLE PHP MVC Framework!

    - by Allen
    I need a simple and basic MVC example to get me started. I dont want to use any of the available packaged frameworks. I am in need of a simple example of a simple PHP MVC framework that would allow, at most, the basic creation of a simple multi-page site. I am asking for a simple example because I learn best from simple real world examples. Big popular frameworks (such as code ignighter) are to much for me to even try to understand and any other "simple" example I have found are not well explained or seem a little sketchy in general. I should add that most examples of simple MVC frameworks I see use mod_rewrite (for URL routing) or some other Apache-only method. I run PHP on IIS. I need to be able to understand a basic MVC framework, so that I could develop my own that would allow me to easily extend functionality with classes. I am at the point where I understand basic design patterns and MVC pretty well. I understand them in theory, but when it comes down to actually building a real world, simple, well designed MVC framework in PHP, i'm stuck. I would really appreciate some help! Edit: I just want to note that I am looking for a simple example that an experienced programmer could whip up in under an hour. I mean simple as in bare bones simple. I dont want to use any huge frameworks, I am trying to roll my own. I need a decent SIMPLE example to get me going.

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  • Secure Password Storage and Transfer

    - by Andras Zoltan
    I'm developing a new user store for my organisation and am now tackling password storage. The concepts of salting, HMAC etc are all fine with me - and want to store the users' passwords either salted and hashed, HMAC hashed, or HMAC salted and hashed - not sure what the best way will be - but in theory it won't matter as it will be able to change over time if required. I want to have an XML & JSON service that can act as a Security Token Service for client-side apps. I've already developed one for another system, which requires that the client double-encrypts a clear-text password using SHA1 first and then HMACSHA1 using a 128 unique key (or nonce) supplied by the server for that session only. I'd like to repeat this technique for the new system - upgrading the algo to SHA256 (chosen since implementations are readily available for all aforementioned platforms - and it's much stronger than SHA1) - but there is a problem. If I'm storing the password as a salted hash in the user-store, the client will need to be sent that salt in order to construct the correct hash before being HMACd with the unique session key. This would completely go against the point of using a salt in the first place. Equally, if I don't use salt for password storage, but instead use HMAC, it's still the same problem. At the moment, the only solution I can see is to use naked SHA256 hashing for the password in the user store, so that I can then use this as a starting point on both the server and the client for a more secure salted/hmacd password transfer for the web service. This still leaves the user store vulnerable to a dictionary attack were it ever to be accessed; and however unlikely that might be - assuming it will never happen simply doesn't sit well with me. Greatly appreciate any input.

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  • CSS sliding-door buttons center alignment

    - by rochal
    Hi guys, I need help to align CSS buttons. I tried many different variations and I just cannot center my button the way I want. Firstly, have a look at this url: http://www.front-end-developer.net/cssbuttons/example.htm I'm using 2 images to form a button (this could be done on 1 image, but in this case we've got two). Everything works as expected as long as we apply float:left or float:right to the parent div element, to 'limit' width of the div and close it as soon as the content of the div ends. You can remove float:left from the button to see what I mean. But what about center positioned buttons? I cannot add float:left/right because I want align it in the middle. In theory, I could set { width:XXpx; margin:0 auto; } And I will get what you can see on this picture: But I don't know the length of the text inside. Having different translations my button can be very short, or 5 times that long. I also tried to use <span> instead of <div>, but unfortunately nested inline elements don't respect their padding correctly... And yes, I must use <a> inside, so buttons can be accessed by web crawlers. I'm really stuck on this one.

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  • My PreferenceActivity does not show up, even though it is in my manifest file

    - by Charlie
    So I am modifying the Cube live wallpaper example. I have a class that extends PreferenceActivity, and I added the Activity in my manifest file. I keep getting ActivityNotFoundExceptions. Here is my preference class : public class MySettingsActivity extends PreferenceActivity implements SharedPreferences.OnSharedPreferenceChangeListener { @Override protected void onCreate(Bundle bundle) { super.onCreate(bundle); getPreferenceManager().setSharedPreferencesName( ParticleCandy.SHARED_PREFS_NAME); addPreferencesFromResource(R.xml.settings); getPreferenceManager().getSharedPreferences().registerOnSharedPreferenceChangeListener( this); } @Override protected void onResume() { super.onResume(); } @Override protected void onDestroy() { getPreferenceManager().getSharedPreferences().unregisterOnSharedPreferenceChangeListener( this); super.onDestroy(); } public void onSharedPreferenceChanged(SharedPreferences sharedPreferences, String key) { } } And here is my manifest file <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.pixel.theory.wallpapers.mywallpaper" android:versionCode="1" android:versionName="1.0"> <application android:icon="@drawable/icon" android:label="@string/app_name"> <service android:label="@string/app_name" android:name="MyWallpaper" android:permission="android.permission.BIND_WALLPAPER" > <intent-filter> <action android:name="android.service.wallpaper.WallpaperService"> </action> </application> <uses-sdk android:minSdkVersion="7" /> <uses-feature android:name="android.software.live_wallpaper" /> </manifest> Any ideas why my preferences activity doesn't get read in from the manifest?

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  • java.net.SocketException: Software caused connection abort: recv failed; Causes and cures?

    - by IVR Avenger
    Hi, all. I've got an application running on Apache Tomcat 5.5 on a Win2k3 VM. The application serves up XML to be consumed by some telephony appliances as part of our IVR infrastructure. The application, in turn, receives its information from a handful of SOAP services. This morning, the SOAP services were timing out intermittently, causing all sorts of Exceptions. Once these stopped, I noticed that our application was still performing very slowly, in that it took it a long time to render and deliver pages. This sluggishness was noticed both on the appliances that consume the Tomcat output, and from a simple test of requesting some static documents from my web browser. Restarting Tomcat immediately resolved the issue. Cracking open the localhost log, I see a ton of these errors, right up until I restarted Tomcat: WARNING: Exception thrown whilst processing POSTed parameters java.net.SocketException: Software caused connection abort: recv failed After a big of Googling, my working theory is that the SOAP issue caused my users to get errors, which caused them to make more requests, which put an increased load on the application. This caused it to run out of available sockets to handle incoming requests. So, here's my quandary: 1. Is this a valid hypothesis, or am I just in over my head with HTTP and Tomcat? 2. If this is a valid hypothesis, is there a way to increase the size of the "socket queue", so that this doesn't happen in the future? Thanks! IVR Avenger

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  • GRAPH PROBLEM: find an algorithm to determine the shortest path from one point to another in a recta

    - by newba
    I'm getting such an headache trying to elaborate an appropriate algorithm to go from a START position to a EXIT position in a maze. For what is worth, the maze is rectangular, maxsize 500x500 and, in theory, is resolvable by DFS with some branch and bound techniques ... 10 3 4 7 6 3 3 1 2 2 1 0 2 2 2 4 2 2 5 2 2 1 3 0 2 2 2 2 1 3 3 4 2 3 4 4 3 1 1 3 1 2 2 4 2 2 1 Output: 5 1 4 2 Explanation: Our agent looses energy every time he gives a step and he can only move UP, DOWN, LEFT and RIGHT. Also, if the agent arrives with a remaining energy of zero or less, he dies, so we print something like "Impossible". So, in the input 10 is the initial agent's energy, 3 4 is the START position (i.e. column 3, line 4) and we have a maze 7x6. Think this as a kind of labyrinth, in which I want to find the exit that gives the agent a better remaining energy (shortest path). In case there are paths which lead to the same remaining energy, we choose the one which has the small number of steps, of course. I need to know if a DFS to a maze 500x500 in the worst case is feasible with these limitations and how to do it, storing the remaining energy in each step and the number of steps taken so far. The output means the agent arrived with remaining energy= 5 to the exit pos 1 4 in 2 steps. If we look carefully, in this maze it's also possible to exit at pos 3 1 (column 3, row 1) with the same energy but with 3 steps, so we choose the better one. With these in mind, can someone help me some code or pseudo-code? I have troubles working this around with a 2D array and how to store the remaining energy, the path (or number of steps taken)....

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  • thread reaches end but isn't removed

    - by pstanton
    I create a bunch of threads to do some processing: new Thread("upd-" + id){ @Override public void run(){ try{ doSomething(); } catch (Throwable e){ LOG.error("error", e); } finally{ LOG.debug("thread death"); } } }.start(); I know i should be using a threadPool but i need to understand the following problem before i change it: I'm using eclipse's debugger and looking at the threads in the debug pane which lists active threads. Many of them complete as you would expect, and are removed from the debug pane, however some seem to stay in the list of active threads even though the log shows the "thread death" entry for these. When i attempt to debug these threads, they either do not pause for debugging or show an error dialog: "A timeout occurred while retrieving stack frames for thread: upd-...". there is some synchronization going on within the doSomething() call but i'm fairly sure it's ok and since the "thread death" log is being called i'm assuming these threads aren't deadlocked in that method. i don't do any Thread.join()s, however i do call a third party API but doubt they do either. Can anyone think of another reason these threads are lingering? Thanks. EDIT: I created this test to check the Garbage Collection theory: Thread thread = new Thread("!!!!!!!!!!!!!!!!") { @Override public void run() { System.out.println("running"); ThreadUs.sleepQuiet(5000); System.out.println("finished"); // <-- thread removed from list here } }; thread.start(); ThreadUs.sleepQuiet(10000); System.out.println(thread.isAlive()); // <-- thread already removed from list but hasn't been GC'd ThreadUs.sleepQuiet(10000); this proves that it is nothing to do with garbage collection as eclipse removes the thread from the thread list as soon as it completes and isn't waiting for the object to be de-referenced/GC'd.

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  • Ninject InThreadScope Binding

    - by e36M3
    I have a Windows service that contains a file watcher that raises events when a file arrives. When an event is raised I will be using Ninject to create business layer objects that inside of them have a reference to an Entity Framework context which is also injected via Ninject. In my web applications I always used InRequestScope for the context, that way within one request all business layer objects work with the same Entity Framework context. In my current Windows service scenario, would it be sufficient to switch the Entity Framework context binding to a InThreadScope binding? In theory when an event handler in the service triggers it's executed under some thread, then if another file arrives simultaneously it will be executing under a different thread. Therefore both events will not be sharing an Entity Framework context, in essence just like two different http requests on the web. One thing that bothers me is the destruction of these thread scoped objects, when you look at the Ninject wiki: .InThreadScope() - One instance of the type will be created per thread. .InRequestScope() - One instance of the type will be created per web request, and will be destroyed when the request ends. Based on this I understand that InRequestScope objects will be destroyed (garbage collected?) when (or at some point after) the request ends. This says nothing however on how InThreadScope objects are destroyed. To get back to my example, when the file watcher event handler method is completed, the thread goes away (back to the thread pool?) what happens to the InThreadScope-d objects that were injected? EDIT: One thing is clear now, that when using InThreadScope() it will not destroy your object when the handler for the filewatcher exits. I was able to reproduce this by dropping many files in the folder and eventually I got the same thread id which resulted in the same exact Entity Framework context as before, so it's definitely not sufficient for my applications. In this case a file that came in 5 minutes later could be using a stale context that was assigned to the same thread before.

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  • PHP database simulation

    - by Emdiesse
    I have a PHP script that works by calling items from a database based upon the time they were placed in there and it deletes them if they are older than 5 minutes. Basically, I want to now simulate what would happen if this database was being updated regularly. So I was considering sticking in some code that loads an XML file then goes through and parses that into the database based upon the time data located within a node of the xml data... but the problem there is I want it to continually loop through an enter this data so it'll never actually run the other processes So I was thinking of having another PHP script do that that could do this independantly of the php script that is going to display this data... In theory: I am looking to have a button that I can press and it will then run some php code to load up an XML file from a directory on my web server and then iterate though the data sending the data, to a database, based upon the time within a node in the PHP script and when the script was first called So back to my page that displayed the data... if I continually hit refresh it will contain different results each time because data is being added by the other process and this php script removes the older data when it is refreshed Any information on this? Is there a way I can silently, and safely, run a php script without it being loaded into a browser... like a thread!?

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  • how useful is Turing completeness? are neural nets turing complete?

    - by Albert
    While reading some papers about the Turing completeness of recurrent neural nets (for example: Turing computability with neural nets, Hava T. Siegelmann and Eduardo D. Sontag, 1991), I got the feeling that the proof which was given there was not really that practical. For example the referenced paper needs a neural network which neuron activity must be of infinity exactness (to reliable represent any rational number). Other proofs need a neural network of infinite size. Clearly, that is not really that practical. But I started to wonder now if it does make sense at all to ask for Turing completeness. By the strict definition, no computer system nowadays is Turing complete because none of them will be able to simulate the infinite tape. Interestingly, programming language specification leaves it most often open if they are turing complete or not. It all boils down to the question if they will always be able to allocate more memory and if the function call stack size is infinite. Most specification don't really specify this. Of course all available implementations are limited here, so all practical implementations of programming languages are not Turing complete. So, what you can say is that all computer systems are just equally powerful as finite state machines and not more. And that brings me to the question: How useful is the term Turing complete at all? And back to neural nets: For any practical implementation of a neural net (including our own brain), they will not be able to represent an infinite number of states, i.e. by the strict definition of Turing completeness, they are not Turing complete. So does the question if neural nets are Turing complete make sense at all? The question if they are as powerful as finite state machines was answered already much earlier (1954 by Minsky, the answer of course: yes) and also seems easier to answer. I.e., at least in theory, that was already the proof that they are as powerful as any computer.

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  • What is the correct way to implement a massive hierarchical, geographical search for news?

    - by Philip Brocoum
    The company I work for is in the business of sending press releases. We want to make it possible for interested parties to search for press releases based on a number of criteria, the most important being location. For example, someone might search for all news sent to New York City, Massachusetts, or ZIP code 89134, sent from a governmental institution, under the topic of "traffic". Or whatever. The problem is, we've sent, literally, hundreds of thousands of press releases. Searching is slow and complex. For example, a press release sent to Queens, NY should show up in the search I mentioned above even though it wasn't specifically sent to New York City, because Queens is a subset of New York City. We may also want to implement "and" and "or" and negation and text search to the query to create complex searches. These searches also have to be fast enough to function as dynamic RSS feeds. I really don't know anything about search theory, or how it's properly done. The way we are getting by right now is using a data mart to store the locations the releases were sent to in a single table. However, because of the subset thing mentioned above, the data mart is gigantic with millions of rows. And we haven't even implemented cities yet, and there are about 50,000 cities in the United States, which will exponentially increase the size of the data mart by so much I'm afraid it just won't work anymore. Anyway, I realize this is not a simple question and there won't be a "do this" answer. However, I'm hoping one of you can point me in the right direction where I can learn about how massive searches are done? Because I really know nothing about it. And such a search engine is turning out to be incredibly difficult to make. Thanks! I know there must be a way because if Google can search the entire internet we must be able to search our own database :-)

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  • Cladogram, tree of life, cladistics, taxonomy in JS or canvas?

    - by boblet
    Good people - I need some help to find a way to create an interactive cladogram or phylogenetic tree (yes, I have read all related posts, and do not find what I am looking for). The thing is, I need the nodes to be name-able. An example would be something like this Most scripts I find are either applets, flash, or simply do not show the node classification, ie it would skip "feliformia" in this example. This is useless to me, as I would then end up with carnivore - anonymous node - anonymous node - anonymous node - tiger, and that is not good. This tree will in theory cover all life, so it could get rather large, and get links and names in english and latin from database. So: no flash, no applets. It must be horizontal, no supertrees (circular). I have gone through this http://bioinfo.unice.fr/biodiv/Tree_editors.html but most of them seems to be either old, not displaying sub-node levels, applets, or way too complex. I imagine this would be a delightful job for canvas/jQuery..? And chances are, someone got there before me? Any pointers much appreciated. Note: if anyone out there would like to do something like this as a project, I will be happy to help, even though it would not benefit me for this project.This type of taxonomy is not as simple as it may seem, and I would be happy see this happen.

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  • MS Surface Tag Visualizer steals contact events

    - by Isak Savo
    I'm struggling with the TagVisualizer control on an MS Surface project. In theory the control seems great, allowing you to respond to input from real world physical objects The problem is that the control will cover the entire screen (since I want to capture tags on the entire screen) and as such, no other controls in my app will receive the touch events. (Unless, they are direct ascendants in the visual tree). In my app, I want to have a "layer" type of a approach, where each layer can respond to (contact) input: Window `- Grid `- LayersPanel `- TagVisualizer `- Layer 1 `- Layer 2 `- Layer 3 `- Layer 4 Now it doesn't matter where I put the tag visualizer, it's always going to steal contact events from all or some of the other layers. (due to the nature of RoutedEvents) To me, it seems like the control is completely useless in practice as it will always interfere with your application's other controls. What am I missing here? So my questions are: Any suggestions on how to work around this? Has anyone used TagVisualizers in a similar scenario? If so, how did you solve this? By the way, the layers all work fine, since they will only steal events that are directly on top of their sub elements (the rest of the layer is invisible to hit testing)

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