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  • Graphical Programming Language

    - by prosseek
    In control engineering or instrumentation, I see Simulink or LabVIEW(G) is pretty popular. In ESL design, I see that Agilent SystemVue is gaining some popularity. If you see the well established compiler theroy, almost 100% is about the textual language. But how about the graphical language? Is there any noticable research or discussion about the graphical programming language? In terms of Theory about Graphical Language - syntactic/semantic analysis and whatever relevant expressiveness (Actually, I asked a question about it at SO - http://stackoverflow.com/questions/2427496/what-do-you-mean-by-the-expressiveness-in-programming-lanuguage) Possibility of the Graphical language ... Or what do you think about the Graphical Programming Language?

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  • Inverted index in a search engine

    - by Ayman
    Hello there, I'm trying to write some code to make a small application for searching text from files. Files should be crawled, and I need to put an inverted index to boost searches. My problem is that I kind of have ideas about how the parser would be, I'm willing to implement the AND, NOT, OR in the query. Whereas, I couldn't figure out how my index should be... I have never created an inverted index so if any body could suggest a feasable way to do it I would be very grateful... I do know in theory how it works but my problem is I absolutely have no idea to make happen in MySql I need to give keywords being indexed a weight too... Thank you so much.

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  • Is there a 3 way merger tool that “understands” common refactoring?

    - by Ian Ringrose
    When a simple refactoring like “rename field” has been done on one branch it can be very hard to merge the changes into the other branches. (Extract method is much harder as the merge tools don’t seem to match the unchanged blocks well) Now in my dreams, I am thinking of a tool that can record (or work out) what well defined refactoring operations have been done on one branch and then “replay” them on the other branch, rather than trying to merge every line the refactoring has affected. see also "Is there an intelligent 3rd merge tool that understands VB.NET" for the other half of my pain! Also has anyone try something like MolhadoRef (blog article about MolhadoRef and Refactoring-aware SCM), This is, in theory, refactoring-aware source control.

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  • will a mysql query run slower if one of the tables involved has no index defined??

    - by lock
    there's this already populated database which came from another dev im not sure what went on that dev's mind when he created the tables, but on one of our scripts there is this query involving 4 tables and it runs super slow SELECT a.col_1, a.col_2, a.col_3, a.col_4, a.col_5, a.col_6, a.col_7 FROM a, b, c, d WHERE a.id = b.id AND b.c_id = c.id AND c.id = d.c_id AND a.col_8 = '$col_8' AND d.g_id = '$g_id' AND c.private = '1' NOTE: $col_8 and $g_id are variables from a form its only my theory that it's due to tables b and c not having an index, although im guessing that the dev didnt think that it was necessary since those tables only tell relations between a and d, where b tells that the data in a belongs to a certain user, and c tells that the user belongs to a group in d as you can see, there's not even a join or other extensive query functions used but this query which returns only around 100 rows takes 2 minutes to execute. anyway my question is simply this post's title. will a mysql query run slower if one of the tables involved has no index defined??

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  • Comparison of music data

    - by Christian P.
    Hey I am looking for theory, algorithms and similar for how to compare music. More specifically, I am looking into how to dupecheck music tracks that have different bitrates or perhaps slightly different variations (radio vs album version), but otherwise sound the same. Use cases for this include services such as Grooveshark, Youtube, etc. where they get a lot of duplicate tracks. I am also interested in text comparisons (Britney Spers vs Britney Spears, how far they deviate, etc.) although this is secondary and I already have some sources to go on in this area. I am mostly interested in codec-agnostic comparison techniques and algoritms (assuming a "raw" stream), but codec-specific resources are appreciated. I am aware of projects such as musicbrainz.org, but have not investigated it further, and would be interested if such projects could be of help in this endeavor.

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  • Android Activity ClassNotFoundException - tried everything

    - by Matthew Rathbone
    I've just refactored an app into a framework library and an application, but now when I try and start the app in the emulator I get the following error stack trace: 06-02 18:22:35.529: E/AndroidRuntime(586): FATAL EXCEPTION: main 06-02 18:22:35.529: E/AndroidRuntime(586): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.matthewrathbone.eastersays/com.matthewrathbone.eastersays.EasterSimonSaysActivity}: java.lang.ClassNotFoundException: com.matthewrathbone.eastersays.EasterSimonSaysActivity in loader dalvik.system.PathClassLoader[/data/app/com.matthewrathbone.eastersays-1.apk] 06-02 18:22:35.529: E/AndroidRuntime(586): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585) 06-02 18:22:35.529: E/AndroidRuntime(586): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679) 06-02 18:22:35.529: E/AndroidRuntime(586): at android.app.ActivityThread.access$2300(ActivityThread.java:125) 06-02 18:22:35.529: E/AndroidRuntime(586): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033) 06-02 18:22:35.529: E/AndroidRuntime(586): at android.os.Handler.dispatchMessage(Handler.java:99) 06-02 18:22:35.529: E/AndroidRuntime(586): at android.os.Looper.loop(Looper.java:123) 06-02 18:22:35.529: E/AndroidRuntime(586): at android.app.ActivityThread.main(ActivityThread.java:4627) 06-02 18:22:35.529: E/AndroidRuntime(586): at java.lang.reflect.Method.invokeNative(Native Method) 06-02 18:22:35.529: E/AndroidRuntime(586): at java.lang.reflect.Method.invoke(Method.java:521) 06-02 18:22:35.529: E/AndroidRuntime(586): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868) 06-02 18:22:35.529: E/AndroidRuntime(586): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626) 06-02 18:22:35.529: E/AndroidRuntime(586): at dalvik.system.NativeStart.main(Native Method) 06-02 18:22:35.529: E/AndroidRuntime(586): Caused by: java.lang.ClassNotFoundException: com.matthewrathbone.eastersays.EasterSimonSaysActivity in loader dalvik.system.PathClassLoader[/data/app/com.matthewrathbone.eastersays-1.apk] 06-02 18:22:35.529: E/AndroidRuntime(586): at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243) 06-02 18:22:35.529: E/AndroidRuntime(586): at java.lang.ClassLoader.loadClass(ClassLoader.java:573) 06-02 18:22:35.529: E/AndroidRuntime(586): at java.lang.ClassLoader.loadClass(ClassLoader.java:532) 06-02 18:22:35.529: E/AndroidRuntime(586): at android.app.Instrumentation.newActivity(Instrumentation.java:1021) 06-02 18:22:35.529: E/AndroidRuntime(586): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577) 06-02 18:22:35.529: E/AndroidRuntime(586): ... 11 more Usually this means that the manifest file is wrong in some way, but I've double checked everything I can think of. Here is my activity class: package com.matthewrathbone.eastersays; import android.os.Bundle; import com.rathboma.simonsays.Assets.Season; import com.rathboma.simonsays.SeasonPicker; import com.rathboma.simonsays.SimonSaysActivity; public class EasterSimonSaysActivity extends SimonSaysActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); } @Override protected void onDestroy() { // TODO Auto-generated method stub super.onDestroy(); } @Override public SeasonPicker getSeasonPicker() { return new SeasonPicker(){ @Override public Season getSeason() { // TODO Auto-generated method stub return Season.EASTER; } }; } } As you can see, it's listed correctly in the manifest: <?xml version="1.0" encoding="utf-8"?> <manifest xmlns:android="http://schemas.android.com/apk/res/android" package="com.matthewrathbone.eastersays" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="7" android:targetSdkVersion="15" /> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name" > <activity android:name=".EasterSimonSaysActivity" android:label="@string/app_name" > <intent-filter> <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application> </manifest> I have no idea how to fix this, and would appreciate any help. I've scanned many similar questions on SO without seeing this particular behavior. More info: I've checked inside the generated APK and the class has an entry in the classes.dex file I've tried cleaning/building the project in eclipse I've tried using a totally new device image that doesn't have a copy of the APK on it already I've changed the library project into a regular java, then changed back into an android project, no difference

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  • Keyboard for programming

    - by exhuma
    This may seem a bit a tangential topic. It's not directly related to actual code, but is important for our line of work nevertheless. Over the years, I've switched keyboards a few times. All of them had slightly different key layouts. And I'm not talking about the language/locale layout, but the physical layout! Why not the locale layout? Well, quite frankly, that's easy to change via software. I personally have a German keyboard but have it set to the UK layout. Why? It's quite hard to find different layouts in the shops where I live. Even ordering is not always easy in the shops. So that leaves me with Internet shops. But I prefer to "test" my keyboards before buying. The most notable changes are: Mangled "Home Key Block" I've seen this first on a Logitech keyboard, but it may have originated elsewhere. Shape of the "Enter" key I've seen three different cases so far: Two lines high, wider at the top Two lines high, wider at the bottom One line high Shape of the Backspace button I've seen two types so far: One "character" wide Two "characters" wide OS Keys For Macs, you have the Option and Command buttons, for Windows you have the Windows and Context Menu buttons. Cherry even produced a Linux keyboard once (unfortunately I cannot find many details except news results). I assume a dedicated Linux keyboard would sport a Compose key and had the SysRq always labelled as well (note that some standard layouts do this already). Obviously... .. all these differences entail that some keys have to be moved around the board a lot. Which means, if you are used to one and have to work on another one, you happen to hit the wrong keys quite often. As it happens, this is much more annoying for programmers as it is for people who write texts. Mainly because the keys which are moved around are special character keys, often used in programming. Often these hardware layouts depend also indirectly on where you buy the keyboards. Honestly, I haven't seen a keyboard with a one-line "Enter" key in Germany, nor Luxembourg. I may just have missed it but that's how it looks to me at least. A survey I've seen some attempts at surveys in the style "which keyboard is best for programming". But they all - in my opinion - are not using comparable sets. So I was wondering if it was possible to concoct a survey taking the above criteria into account. But ignoring key dimensions that one would be a bit overkill I guess ;) From what I can see there are the following types of physical layout: Backspace: 2-characters wide Enter: 2-Lines, wider top Backspace: 2-characters wide Enter: 1-Line Backspace: 1-character wide Enter: 2-Lines, wider bottom Then there are the other possible permutations (home-key block, os-keys), which in total makes for quite a large list of categories. Now, I wonder... Would anyone be interested in such a survey? I personally would. Because I am looking for the perfect fit for me. If yes, then I could really use the help of anyone here to propose some models to include in the survey. Once I have some models for each category (I'd say at least 3 per category) I could go ahead and write up a survey, put it on-line and let the it collect data for a while. What do you think?

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  • Is this way the best solution to read and save images from Rss Feeds?

    - by Keyne
    Hi, I've build a "RSS Feed Reader" module to my application, and for every post with images in the content, I get the first that matches a specific size and then I save for future use as reference to the posts. When processing, everything works properly except when more then 10 images are saved at the same time (This value is variable). I got an 404 error after a while saving the images. Some images are saved, but not all of them. If I run the app in my local server, everything work as expected (using set_timeout(0) to avoid timeout errors). Currently my application is hosted at dreamhost and I'm using Zend Framework. I'm not sure if the problem is specif for Zend Framework applications, so I didn't put any tags about. I've had this problem another time with other projects hosted at dreamhost. They seems to limitate memory for operations like that. My question is: There is a better way to save images then this (maybe in background? a limited amount per operation?): require_once(APPLICATION_PATH . '/../library/simplehtmldom/simple_html_dom.php'); $TableFeeds = new Model_DbTable_Feeds(); $Feeds = $TableFeeds->fetchAll(); foreach($Feeds as $Feed) { $entries = Zend_Feed_Reader::import($Feed->link); $lastEntry = $this->getLastEntry($Feed->id); if($lastEntry) { $lastDate = new Zend_Date($lastEntry->created_at, Zend_Date::ISO_8601); } foreach ($entries as $entry) { if($lastDate) { if(strtotime($lastDate->get('y-M-d H:m:s')) >= strtotime($entry->getDateCreated()->get('y-M-d H:m:s'))) { break; } } $Category = new Model_DbTable_Categorias(); $availableCategories = $Category->getList('slug'); $categoria_id = false; foreach ($categories as $cat) { if(!empty($cat) && !$categoria_id) { $slug = Zf_Convert::slugfy($cat); if($availableCategories[$Feed->categoria_id] == $slug) { $categoria_id = $Feed->categoria_id; break; } if(in_array($slug,$availableCategories)) { $categoria_id = array_search($slug,$availableCategories); break; } } } if(!$categoria_id) { $categoria_id = $Feed->categoria_id; } // Cadastra a entrada $data = array( 'categoria_id' => $categoria_id, 'feed_id' => $Feed->id, 'titulo' => $entry->getTitle(), 'slug' => Zf_Convert::slugfy($entry->getTitle()), 'created_at' => $entry->getDateCreated()->get(Zend_Date::ISO_8601), 'link' => $entry->getLink(), 'html' => $entry->getContent(), 'tags' => $tags ); $entry_id = $this->insert($data); if($categoria_id == 2) { set_time_limit(0); $post_dom = str_get_dom($entry->getContent()); $img_tags = $post_dom->find('img'); $images = array(); foreach($img_tags as $image) { $images[] = $image->src; } if(count($images)) { $i = 0; $saved = false; while($images[$i] && !$saved) { $src = $images[$i]; $imagem = Zf_Image::create($src); $size = $imagem->getCurrentDimensions(); if($size['width'] >= 150 && $size['height'] >= 200) { $imagem->adaptiveResize(200,200); $imagem->save(PUBLIC_PATH . '/img/feeds/manchetes/' . $entry_id . '.jpg'); $saved = true; $this->update(array('imagemChamada' => 1),'id =' . $entry_id); } $i++; } } } } } }

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  • Is there a reason why a submit button would fail in ie6 using jquery?

    - by kgrad
    I have a form being submit to a servlet, there is a jQuery Datepicker on the page. On some computers using ie6, for some reason the page is crashing on submit. I am getting a 404 error, but only sometimes. I have no idea why this would occur. My theory is that somehow it's bypassing the servlet, or its not loading jquery properly, or... I am at a loss. What are some reasons why this could occur on some computers? The exact version of ie6 is 6.0.2900.2180, on windows XP SP2. How can I test with this specific version?

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  • Delphi form icons are blurry on Windows 7's taskbar (with MainFormOnTaskbar enabled)

    - by Dennis G.
    We have a Windows desktop application written in Delphi that works fine on Windows 7, except that the icon of the main form looks blurry in Windows' new taskbar. As long as the application has not been started the icon looks fine (i.e. when it's pinned to the taskbar). Once it has been started Windows uses the icon of the main form (instead of the .exe resource icon) and it's blurry (it looks like a 16x16 version of the icon is scaled up). The icon that we use for the .exe and for the main form are exactly the same and it contains all kinds of resolutions, including 48x48 with alpha blending. My theory is that Delphi ignores/deletes the extra resolutions of the icon when I import the .ico file for the main form in Delphi. Is there a way to prevent/fix this? What's the best way to ensure that an application written in Delphi uses the correct icon resolution in Windows 7's taskbar?

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  • Python Pari Library?

    - by silinter
    Pari/GP is an excellent library for functions relating to number theory. The problem is that there doesn't seem to be an up to date wrapper for python anywhere around, (pari-python uses an old version of pari) and I'm wondering if anyone knows of some other library/wrapper that is similar to pari or one that uses pari. I'm aware of SAGE, but it's far too large for my needs. GMPY is excellent as well, but there are some intrinsic pari functions that I miss, and I'd much rather use python than the provided GP environment. NZMATH, mpmath, scipy and sympy were all taken into consideration as well. On a related note, does anyone have any suggestions on loading the pari dll itself and using the functions contained in it? I've tried to very little success, other than loading it and learning about function pointers.

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  • Action bar with Search View. Reverse compatibility issues

    - by suresh
    I am building a sample app to demonstrate SearchView with filter and other Action Bar items. I am able to successfully run this app on 4.2(Nexus 7). But it is not running on 2.3. I googled about the issue. Came to know that i should use SherLock Action bar. I just went to http://actionbarsherlock.com/download.html, downloaded the zip file and added the library as informed in the video: http://www.youtube.com/watch?v=4GJ6yY1lNNY&feature=player_embedde by WiseManDesigns. But still I am unable to figure out the issue. Here is my code: SearchViewActionBar.java public class SearchViewActionBar extends Activity implements SearchView.OnQueryTextListener { private SearchView mSearchView; private TextView mStatusView; int mSortMode = -1; private ListView mListView; private ArrayAdapter<String> mAdapter; protected CharSequence[] _options = { "Wild Life", "River", "Hill Station", "Temple", "Bird Sanctuary", "Hill", "Amusement Park"}; protected boolean[] _selections = new boolean[ _options.length ]; private final String[] mStrings = Cheeses.sCheeseStrings; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); getWindow().requestFeature(Window.FEATURE_ACTION_BAR); setContentView(R.layout.activity_main); // mStatusView = (TextView) findViewById(R.id.status_text); // mSearchView = (SearchView) findViewById(R.id.search_view); mListView = (ListView) findViewById(R.id.list_view); mListView.setAdapter(mAdapter = new ArrayAdapter<String>(this, android.R.layout.simple_list_item_1, mStrings)); mListView.setTextFilterEnabled(true); //setupSearchView(); } private void setupSearchView() { mSearchView.setIconifiedByDefault(true); mSearchView.setOnQueryTextListener(this); mSearchView.setSubmitButtonEnabled(false); //mSearchView.setQueryHint(getString(R.string.cheese_hunt_hint)); } @Override public boolean onCreateOptionsMenu(Menu menu) { super.onCreateOptionsMenu(menu); MenuInflater inflater = getMenuInflater(); inflater.inflate(R.menu.searchview_in_menu, menu); MenuItem searchItem = menu.findItem(R.id.action_search); mSearchView = (SearchView) searchItem.getActionView(); //setupSearchView(searchItem); setupSearchView(); return true; } @Override public boolean onPrepareOptionsMenu(Menu menu) { if (mSortMode != -1) { Drawable icon = menu.findItem(mSortMode).getIcon(); menu.findItem(R.id.action_sort).setIcon(icon); } return super.onPrepareOptionsMenu(menu); } @Override public boolean onOptionsItemSelected(MenuItem item) { String c="Category"; String s=(String) item.getTitle(); if(s.equals(c)) { System.out.println("same"); showDialog( 0 ); } //System.out.println(s); Toast.makeText(this, "Selected Item: " + item.getTitle(), Toast.LENGTH_SHORT).show(); return true; } protected Dialog onCreateDialog( int id ) { return new AlertDialog.Builder( this ) .setTitle( "Category" ) .setMultiChoiceItems( _options, _selections, new DialogSelectionClickHandler() ) .setPositiveButton( "SAVE", new DialogButtonClickHandler() ) .create(); } public class DialogSelectionClickHandler implements DialogInterface.OnMultiChoiceClickListener { public void onClick( DialogInterface dialog, int clicked, boolean selected ) { Log.i( "ME", _options[ clicked ] + " selected: " + selected ); } } public class DialogButtonClickHandler implements DialogInterface.OnClickListener { public void onClick( DialogInterface dialog, int clicked ) { switch( clicked ) { case DialogInterface.BUTTON_POSITIVE: printSelectedPlanets(); break; } } } protected void printSelectedPlanets() { for( int i = 0; i < _options.length; i++ ){ Log.i( "ME", _options[ i ] + " selected: " + _selections[i] ); } } public void onSort(MenuItem item) { mSortMode = item.getItemId(); invalidateOptionsMenu(); } public boolean onQueryTextChange(String newText) { if (TextUtils.isEmpty(newText)) { mListView.clearTextFilter(); } else { mListView.setFilterText(newText.toString()); } return true; } public boolean onQueryTextSubmit(String query) { mStatusView.setText("Query = " + query + " : submitted"); return false; } public boolean onClose() { mStatusView.setText("Closed!"); return false; } protected boolean isAlwaysExpanded() { return false; } }

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  • Open Source Code Integrity - How does quality assurance work?

    - by rockinthesixstring
    I've thought about this before and this topic has often steered me away from Open Source projects. Recently DotNetPanel has changed it's name to WebSitePanel and gone Open Source. The rumor mill is speculating that Microsoft is behind this. My question (in multi-part) is quite simple. Can somebody please explain to me how quality assurance works on Open Source projects? How can a closed application get "only better" when Open Source? Doesn't the "too many cooks in the kitchen" theory apply when too many developers contribute (possibly bad) code to a project?

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  • What are the prerequisites for learning embedded systems programming ?

    - by WarDoGG
    I have completed my graduation in Computer engineering. We had some basic electronics courses in Digital signal processing, Information theory etc but my primary field is Programming. However, i was looking to get into Embedded sytems programming with NO knowledge of how it is done. However, i am very keen on going into this field. My questions : what are the languages used to program embedded system programs ? Will i be able to learn without having any basics in electronics ? any other prerequisites that i should know ?

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  • ie9/CSS: Flyout menu not working in ie9, but looks great in Firefox/Chrome

    - by Brandon
    Please see this flyout menu: http://www.caseen.com/store.html. It looks amazing in both Firefox and Chrome, but not in IE9! Trying to see what is going on =(. It looks like ie9 is completing ignoring the stylesheet, but in error checking and clicking ie9 direct mode, it shows up however VERY ugly with huge nasty white borders around the links! Please see my code: <div class="flyout"> <ul> <!--START: CATEGORIES--> <!--START: CATEGORY_FORMAT--> <li><a href="view_category.asp?cat=CATID">&nbsp;CATEGORY</a> <!--END: CATEGORY_FORMAT--> <ul><!--START: SUB_CATEGORY_FORMAT--> <li><a href="view_category.asp?cat=CATID">&nbsp;CATEGORY</a></li> <!--END: SUB_CATEGORY_FORMAT--></ul> <!--END: CATEGORIES--> </li> </ul> </div> AND CSS .flyout { width: 130px; height: auto; position:relative; margin: -10 0; padding: 0; z-index:10000; } .flyout ul li a { display:block; text-decoration:none; color: #fff; width: 130px; border: solid; border-color: #000; border-width: 0 0 0 5px; text-align:left; font-size:12px; line-height: 25px; } .flyout ul { padding:0px; list-style-type: none; } .flyout ul li { float:left; margin-right:1px; position:relative; } .flyout ul li ul { display: none; } .flyout ul li:hover a { border: solid; border-color: #fff; border-width: 0 2 0 5px; color: #60dfe5; } .flyout ul li:hover ul { display:block; position:absolute; top:0; left:130px; width:10px; } .flyout ul li:hover ul li a.hide { background:#000; color:#fff; } .flyout ul li:hover ul li:hover a.hide {width:180px;} .flyout ul li:hover ul li ul {display: none;} .flyout ul li:hover ul li a { display:block; background:#000; color:#60dfe5; width:200px; } .flyout ul li:hover ul li a:hover { background:#000; color:#fff; } Thanks, Brandon

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  • How to associate Wi-Fi beacon info with a virtual "location"?

    - by leander
    We have a piece of embedded hardware that will sense 802.11 beacons, and we're using this to make a map of currently visible bssid -> signalStrength. Given this map, we would like to make a determination: Is this likely to be a location I have been to before? If so, what is its ID? If not, I should remember this location: generate a new ID. Now what should I store (and how should I store it) to make future determinations easier? This is for an augmented-reality app/game. We will be using it to associate particular characters and events with "locations". The device does not have internet or cellular access, so using a geolocation service is out of consideration for the time being. (We don't really need to know where we are in reality, just be able to determine if we return there.) It isn't crucial that it be extremely accurate, but it would be nice if it was tolerant to signal strength changes or the occasional missing beacon. It should be usable in relatively low numbers of access points (e.g. rural house with one wireless router) or many (wandering around a dense metropolis). In the case of a city, it should change location every few minutes of walking (continuously-overlapping signals make this a bit more tricky in naive code). A reasonable number of false positives (match a location when we aren't actually there) is acceptable. The wrong character/event showing up just adds a bit of variety. False negatives (no location match) are a bit more troublesome: this will tend to add a better-matching new location to the saved locations, masking the old one. While we will have additional logic to ensure locations that the device hasn't seen in a while will "orphan" any associated characters or events (if e.g. you move to a different country), we'd prefer not to mask and eventually orphan locations you do visit regularly. Some technical complications: signalStrength is returned as 1-4; presumably it's related to dB, but we are not sure exactly how; in my experiments it tends to stick to either 1 or 4, but occasionally we see numbers in between. (Tech docs on the hardware are sparse.) The device completes a scan of one-quarter of the channel space every second; so it takes about 4-5 seconds to get a complete picture of what's around. The list isn't always complete. (We are making strides to fix this using some slight sampling period randomization, as recommended by the library docs. We're also investigating ways to increase the number of scans without killing our performance; the hardware/libs are poorly behaved when it comes to saturating the bus.) We have only kilobytes to store our history. We have a "working" impl now, but it is relatively naive, and flaky in the face of real-world Wi-Fi behavior. Rough pseudocode: // recordLocation() -- only store strength 4 locations m_savedLocations[g_nextId++] = filterForStrengthGE( m_currentAPs, 4 ); // determineLocation() bestPoints = -inf; foreach ( oldLoc in m_savedLocations ) { points = 0.0; foreach ( ap in m_currentAPs ) { if ( oldLoc.has( ap ) ) { switch ( ap.signalStrength ) { case 3: points += 1.0; break; case 4: points += 2.0; break; } } } points /= oldLoc.numAPs; if ( points > bestPoints ) { bestLoc = oldLoc; bestPoints = points; } } if ( bestLoc && bestPoints > 1.0 ) { if ( bestPoints >= (2.0 - epsilon) ) { // near-perfect match. // update location with any new high-strength APs that have appeared bestLoc.addAPs( filterForStrengthGE( m_currentAPs, 4 ) ); } return bestLoc; } else { return NO_MATCH; } We record a location currently only when we have NO_MATCH and the app determines it's time for a new event. (The "near-perfect match" code above would appear to make it harder to match in the future... It's mostly to keep new powerful APs from being associated with other locations, but you'd think we'd need something to counter this if e.g. an AP doesn't show up in the next 10 times I match a location.) I have a feeling that we're missing some things from set theory or graph theory that would assist in grouping/classification of this data, and perhaps providing a better "confidence level" on matches, and better robustness against missed beacons, signal strength changes, and the like. Also it would be useful to have a good method for mutating locations over time. Any useful resources out there for this sort of thing? Simple and/or robust approaches we're missing?

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  • Is there a DRMAA Java library that works with Torque/PBS?

    - by dondondon
    Does anybody know a Java implementation of the DRMAA-API that is known to work with PBS/Torque cluster software? The background behind this: I would like to submit jobs to a newly set-up linux cluster from java using a DRMAA compliant API. The cluster is managed by PBS/Torque. Torque includes PBS DRMAA 1.0 library for Torque/PBS that contains a DRMA-C binding and provides in libdrmaa.so and .a binaries. I know that Sun grid engine includes a drmaa.jar providing a Java-DRMAA API. In fact I opted to use SGE but it was decided to try PBS first. The theory behind that decision was: 'DRMAA is a standard and therefore a Java API needs only a standards compliant drmaa-c binding.' However, I couldn't find such 'general DRMAA-C-java API' and now assume that this assumption is wrong and that the Java libraries are engine specific. Are we stuck here? Any comments appreciated.

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  • System.Drawing.Image for Images in Business Objects?

    - by Mudu
    Hi Folks I'd like to store an image in a business object. In MSDN I saw that the System.Drawing-namespace provides lots of GDI+-features, etc. Is it okay to store an Image in an System.Drawing.Image class in business layer (which is a class library "only"), and thus including a reference to System.Drawing too? I slightly feel just kind of bad doing that, 'cause it seems like I have UI-specific references in business code. Moreover, the code could become unnecessarily platform-dependant (though this is only a problem in theory, because we do not develop for multiple platforms). If it isn't right that way, which type would fit best? Thank you for any response! Matthias

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  • Fatal Error when using ADODB in VB6 on Windows Server 2003 SP2

    - by m.edmondson
    We've got a legacy app (VB6) which works fine on an old Windows Server 2003 box and has been for many years. Recently we've had to move it to a different physical location and in doing this we cloned the box with virtualisation and placed it elsewhere. In theory these two environments should be identical. On the new box however the app falls over when calling the RecordCount method of an ADODB.Recordset. I should say that I can successfully read the ADODB.RecordSet.Properties.Count property with no problem on the line before. The event viewer reports the following: Event Type: Error Event Source: Application Error Event Category: (100) Event ID: 1000 Date: 28/09/2012 Time: 11:15:27 User: N/A Computer: APP01 Description: Faulting application Control.exe, version 1.0.0.6, faulting module ntdll.dll, version 5.2.3790.4789, fault address 0x0002c6e4. I can only imagine there is something wrong with using ADODB within a virtualised environment. Any ideas?

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  • Resources for how to design graph/charts well

    - by wesgarrison
    One of my projects needs to show users where they rank in certain calculations. I inherited the graph structure from the previous programmer and had to leave it alone while I worked on other parts of the site. It's time to make the graphs more meaningful, so I'm looking for books/websites/etc about graphs. (Not graph theory!) Charts that convey comparisons at a glance. Everyone suggests The Visual Display of Quantitative Information by Edward Tufte and that's spot on for what I'm looking for, so anything related to that would be great. Naturally, personal experience about what to do or not would be helpful as well.

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  • Grand Central Strategy for Opening Multiple Files

    - by user276632
    I have a working implementation using Grand Central dispatch queues that (1) opens a file and computes an OpenSSL DSA hash on "queue1", (2) writing out the hash to a new "side car" file for later verification on "queue2". I would like to open multiple files at the same time, but based on some logic that doesn't "choke" the OS by having 100s of files open and exceeding the hard drive's sustainable output. Photo browsing applications such as iPhoto or Aperture seem to open multiple files and display them, so I'm assuming this can be done. I'm assuming the biggest limitation will be disk I/O, as the application can (in theory) read and write multiple files simultaneously. Any suggestions? TIA

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  • facebook with openid

    - by Stacey
    Referencing http://stackoverflow.com/questions/1827997/is-facebook-an-openid-provider here. This is kind of an additional question based on it. I have also read the article at : http://stackoverflow.com/questions/2264266/what-is-the-openid-url-of-facebook - but I am still pretty confused on the whole ordeal. The goal is for people who use facebook to easily login to our website, not to neccessarily integrate with facebook and add things to it (yet). I have read the documentation on facebook connect and am still having trouble grasping exactly what we need to do to accomplish this. I notice that it says that facebook accepts openid logins - so in theory someone with a facebook account could login to a site that took other openid logins, correct? Or do I have to code a separate 'facebookconnect' system just to accept logins from facebook accounts?

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  • Top techniques to avoid 'data scraping' from a website database

    - by Addsy
    I am setting up a site using PHP and MySQL that is essentially just a web front-end to an existing database. Understandably my client is very keen to prevent anyone from being able to make a copy of the data in the database yet at the same time wants everything publicly available and even a "view all" link to display every record in the db. Whilst I have put everything in place to prevent attacks such as SQL injection attacks, there is nothing to prevent anyone from viewing all the records as html and running some sort of script to parse this data back into another database. Even if I was to remove the "view all" link, someone could still, in theory, use an automated process to go through each record one by one and compile these into a new database, essentially pinching all the information. Does anyone have any good tactics for preventing or even just dettering this that they could share. Thanks

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  • Freebase Query with "JOINS"

    - by codemonkey
    ... Yeah, yeah, I know traditional joins don't exist. I actually like the freebase query methodology in theory, just having a little trouble getting it to actually work for me : ) Anyone have a dumb-simple example of getting Freebase data via MQL that pulls from two different "tables"? In particular, I'm trying to get automotive data... so for example, pulling fields from both /automotive/model_year and /automotive/trim_year. I've read the documentation (for hours actually). There's a distinct possibility that I'm looking right at such an example somewhere and just not seeing it because my OLTP brain just doesn't comprehend what it's seeing. * Note * ... that the two "types" I'm working with above are siblings, not parent/child. Does freebase even allow joining data between sibling nodes... I see examples of queries pulling from parent/child, but not from siblings I don't think (or I've overlooked them).

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  • Does the .NET CLR Really Optimize for the Current Processor

    - by dewald
    When I read about the performance of JITted languages like C# or Java, authors usually say that they should/could theoretically outperform many native-compiled applications. The theory being that native applications are usually just compiled for a processor family (like x86), so the compiler cannot make certain optimizations as they may not truly be optimizations on all processors. On the other hand, the CLR can make processor-specific optimizations during the JIT process. Does anyone know if Microsoft's (or Mono's) CLR actually performs processor-specific optimizations during the JIT process? If so, what kind of optimizations?

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