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  • Which knowledge base/rule-based inference engine to choose for real time Runway incursion prevention

    - by Piligrim
    Hello, we are designing a project that would listen to dialog between airport controllers and pilots to prevent runway incursions (eg. one airplane is taking off while other is crossing the runway). Our professor wants us to use Jena for knowledge base (or anything else but it should be some sort of rule-based engine). Inference is not the main thing in Jena and there's not much documentation and examples of this. So we need an engine that would get messages from pilots as input and output possible risks of incursion or any other error in message protocol. It should be easy to write rules, and should be easy to provide engine with real time data. I image it something like this: A pilot sends a message that he lands on some runway, the system remembers that the runway is busy and no one should cross it If someone is given an instruction to cross this runway, the engine should fire a rule that something is wrong When the pilot sends a message that he left the runway and goes to the gate, the system clears the runway and lets other planes to use it. So is Jena, or prolog or any other rules engine suitable for this? I mean it is suitable, but do we really need to use it? I asked the prof. if we could just keep state of the runway and use some simple checks based on messages we receive and he said that it is not scalable and we need the knowledge base. Can someone give me any advise on which approach to use for this system? If you recommend k.b., then which one should we use? The project is written in java. Thank you.

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  • android checkbox box issue

    - by raqz
    i have this check box in a alertdialog. when i try to check the state of the checkbox, the application force closes. any idea why? LayoutInflater factory = LayoutInflater.from(NewActivity.this); final View textDisplayView = factory.inflate(R.layout.nearestlocs, null); final AlertDialog.Builder newAlert = new AlertDialog.Builder(NewActivity.this); newAlert.setView(textDisplayView); final CheckBox checkBoxLab = (CheckBox) findViewById(R.id.checkboxlab); newAlert.setPositiveButton("Display on Map", new DialogInterface.OnClickListener() { public void onClick(DialogInterface dialog, int whichButton) { if(checkBoxLab.isChecked()){ libDisplayFlag = true; } error log 03-13 08:01:58.273: ERROR/AndroidRuntime(6188): Uncaught handler: thread main exiting due to uncaught exception 03-13 08:01:58.292: ERROR/AndroidRuntime(6188): java.lang.NullPointerException 03-13 08:01:58.292: ERROR/AndroidRuntime(6188): at com.isproj3.NewActivity$3.onClick(NewActivity.java:158) 03-13 08:01:58.292: ERROR/AndroidRuntime(6188): at com.android.internal.app.AlertController$ButtonHandler.handleMessage(AlertController.java:158) 03-13 08:01:58.292: ERROR/AndroidRuntime(6188): at android.os.Handler.dispatchMessage(Handler.java:99) xml <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent"> <LinearLayout android:orientation="horizontal" android:gravity="center" android:layout_width="fill_parent" android:layout_height="fill_parent" android:layout_weight="1"> <CheckBox android:id="@+id/checkboxlib" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Library" android:gravity="left" android:textColor="#FF0000" android:paddingBottom="5px" android:textSize="07pt" android:checked="true" /> <TextView android:id="@+id/librarytext" android:layout_width="wrap_content" android:layout_height="wrap_content" android:gravity="center" android:paddingBottom="5px" android:textSize="8pt" /> </LinearLayout> </LinearLayout>

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  • UIImagePickerController shows last picture taken instead of camera input

    - by jules
    I'm having a strange behaviour within my app. For taking pictures i'm using the following pretty standard code for displaying the UIImagePickerController: UIImagePickerController *picker = [[UIImagePickerController alloc] init]; picker.delegate = self; picker.allowsEditing = NO; picker.sourceType = UIImagePickerControllerSourceTypeCamera; [self presentViewController:picker animated:YES completion:nil]; It works perfectly fine the first time I tap the button which calls this action. The strange behaviour starts when I tap that button again. The UIImagePickerController starts again BUT it doesnt show the input from the camera anymore. It shows the last picture I've taken. More Details of this state: Tapping on the image shows the yellow square of the auto focus. (which it actually uses to focus the camera correctly) When I tap on the ImageCapture button - the correct image is taken and presented on the screen. If I take a picture and press 'Retake' the regular camera image is presented as input. More weirdness: It has nothing to do with the iPad I'm using. Creating a new example app which only has button which calls the code from above everything works perfectly fine. I assume it has something to do with the configuration of the app. Therefore I checked everything but could not find any differences which may cause this issue. Thanks in advance for any advice! Update: I do implement the UIImagePickerControllerDelegate in order to dismiss the UIImagePickerController.

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  • vimscript: calling dictionary functions with call()

    - by intuited
    I'm hoping to call a "static" dictionary function using call(). By "static" I mean that the keyword 'dict' is not used in the function's definition. I use this nomenclature in the hopes that the effect of this keyword is to declare a static member function as is possible in java/C++/etc, ie to put the function name in the class namespace but allow it to be called without referencing an object. However this doesn't seem to work. For example: " Setup: let testdict = { } funct! testdict.funct() echo "called" endfunct " Tests: " Following each line is an indented comment " containing its output in message land, ie what was echoed. call testdict.funct() " called echo testdict.funct " 667 echo string(testdict.funct) " function('667') echo function('667') " E475: Invalid argument: 667 echo function('testdict.funct') " testdict.funct call call(testdict.funct, [ ]) " E725: Calling dict function without Dictionary: 667 " Same deal if there's an intermediate variable involved. let TestdictDotFunct = testdict.funct echo TestdictDotFunct " 667 echo string(TestdictDotFunct) " function('667') call TestdictDotFunct() " E725: Calling dict function without Dictionary: 667 From the help topic E725: It is also possible to add a function without the "dict" attribute as a Funcref to a Dictionary, but the "self" variable is not available then. So logic would seem to indicate that if "self" is not available, then it should be possible to call the function referenced by the Funcref without a Dictionary. However this doesn't seem to be the case. Am I missing something? Vim version info: $ aptitude show vim-gnome Package: vim-gnome State: installed Automatically installed: no Version: 2:7.2.245-2ubuntu2

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  • Is this a good approach to address double-base64-encoding?

    - by Freiheit
    My software understands attachments, like PNGs attached to user records. These attachments are usually sent in from outside sources as a Base64 encoded string. The database stores whatever data it is given, Base64 encoded or not. When I serve up the attachment for download I do this: if (Base64.isBase64(data)) { data = Base64.decodeBase64(data); } There is a potential for data that is double encoded. For instance the sender of a message had base64 encoded data, then encoded it again when building the message to send to me. I think the following code would address that circumstance: while (Base64.isBase64(data)) { data = Base64.decodeBase64(data); } So if data is encoded multiple times, it would be decoded until its in its 'raw' state and then served up for download. Is this approach an acceptable way to address that problem? Ideally some sort of checking could happen at the edge when I receive attachment data, but that will take more time. This looping seems to be a faster way to do it. The 'Base64' library is Apache Commons: http://commons.apache.org/codec/apidocs/org/apache/commons/codec/binary/Base64.html I trust it to properly identify Base64 encoded data.

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  • Bind postback data from a strong type view of type List<T>

    - by Robert Koritnik
    I have a strong type view of type List<List<MyViewModelClass>> The outer list will always have two lists of List<MyViewModelClass>. For each of the two outer lists I want to display a group of checkboxes. Each set can have an arbitrary number of choices. My view model class looks similar to this: public class MyViewModelClass { public Area Area { get; set; } public bool IsGeneric { get; set; } public string Code { get; set; } public bool IsChecked { get; set; } } So the final view will look something like: Please select those that apply: First set of choices: x Option 1 x Option 2 x Option 3 etc. Second set of choices: x Second Option 1 x Second Option 2 x Second Option 3 x Second Option 4 etc. Checkboxes should display MyViewModelClass.Area.Name, and their value should be related to MyViewModelClass.Area.Id. Checked state is of course related to MyViewModel.IsChecked. Question I wonder how should I use Html.CheckBox() or Html.CheckBoxFor() helper to display my checkboxes? I have to get these values back to the server on a postback of course. I would like to have my controller action like one of these: public ActionResult ConsumeSelections(List<List<MyViewModelClass>> data) { // process data } public ActionResult ConsumeSelections(List<MyViewModelClass> first, List<MyViewModelClass> second) { // process data } If it makes things simpler, I could make a separate view model type like: public class Options { public List First { get; set; } public List Second { get; set; } } As well as changing my first version of controller action to: public ActionResult ConsumeSelections(Options data) { // process data }

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  • Android: How to get a custom view to redraw partially?

    - by Peterdk
    I have a custom view that fills my entire screen. (A piano keyboard) When a user touches the key, it would cause a invalidate() to be called and the whole keyboard gets redrawn to show the new state with a touched key. Currently the view is very simple, but I plan to add a bit more nice graphics. Since the whole keyboard is dynamically rendered this would make redrawing the entire keyboard more expensive. So I thought, let's look into partial redrawing. Now I call invalidate(Rect dirty) with the correct dirty region. I set my onDraw(Canvas canvas) method to only draw the keys in the dirty region if I do indeed want a partial redraw. This results in those keys being drawn, but the rest of the keyboard is totally black/not drawn at all. Am I wrong in expecting that calling invalidate(Rect dirty) would "cache" the current canvas, and only "allows" drawing in the dirty region? Is there any way I can achieve what I want? (A way to "cache" the canvas and only redraw the dirty area?"

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  • Automation Error upon running VBA script in Excel

    - by brohjoe
    Hi guys, I'm getting an Automation error upon running VBA code in Excel 2007. I'm attempting to connect to a remote SQL Server DB and load data to from Excel to SQL Server. The error I get is, "Run-time error '-2147217843(80040e4d)': Automation error". I checked out the MSDN site and it suggested that this may be due to a bug associated with the sqloledb provider and one way to mitigate this is to use ODBC. Well I changed the connection string to reflect ODBC provider and associated parameters and I'm still getting the same error. Here is the code with ODBC as the provider: Dim cnt As ADODB.Connection Dim rst As ADODB.Recordset Dim stSQL As String Dim wbBook As Workbook Dim wsSheet As Worksheet Dim rnStart As Range Public Sub loadData() 'This was set up using Microsoft ActiveX Data Components version 6.0. 'Create ADODB connection object, open connection and construct the connection string object. Set cnt = New ADODB.Connection cnt.ConnectionString = _ "Driver={SQL Server}; Server=onlineSQLServer2010.foo.com; Database=fooDB Uid=logonalready;Pwd='helpmeOB1';" cnt.Open On Error GoTo ErrorHandler 'Open Excel and run query to export data to SQL Server. strSQL = "SELECT * INTO SalesOrders FROM OPENDATASOURCE('Microsoft.ACE.OLEDB.12.0', & _ "'Data Source=C:\Database.xlsx; Extended Properties=Excel 12.0')...[SalesOrders$]" cnt.Execute (strSQL) 'Error handling. ErrorExit: 'Reclaim memory from the connection objects Set rst = Nothing Set cnt = Nothing Exit Sub ErrorHandler: MsgBox Err.Description, vbCritical Resume ErrorExit 'clean up and reclaim memory resources. cnt.Close If CBool(cnt.State And adStateOpen) Then Set rst = Nothing Set cnt = Nothing End If End Sub

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  • managed beans as managed properties

    - by Sean
    I am using JSF 1.1 on WebSphere 6.1. I am building search functionality within an application and am having some issues. I've stripped out the extras, and have left myself with the following: 4 managed beans: SearchController - Controller bean, session scope SearchResults - session scope (store the results) ProductSearch - session scope (store the search conditions) ResultsBacking - Backing bean for DataTable, used to determine which row was clicked, request scope The SearchController bean has, as managed properties, the other 3. All except ResultsBacking are session scoped. If there is only 1 item in the search results, I want to bring up that record directly. I call setFirst(0) for the data table in the ResultsBacking method (I want to use the existing method that handle which item was clicked, so this is called right after the setFirst). When I go to do another search, I get an IllegalArgumentException when calling getRowData in the data table. According to the api, this is thrown 'if now(sic) row data is available at the currently specified row index'. I'm confused as to why this happens. It works the first time but not the second. Do I need to remove the ResultsBacking on a new search to get rid of the old state?

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  • Problem parsing an atom feed using simplexml_load_file(), can't get an attribute.

    - by Craig Ward
    Hi, I am trying to create a social timeline. I pull in feeds form certain places so I have a timeline of thing I have done. The problem I am having is with Google reader Shared Items. I want to get the time at which I shared the item which is contained in <entry gr:crawl-timestamp-msec="1269088723811"> Trying to get the element using $date = $xml->entry[$i]->link->attributes()->gr:crawl-timestamp-msec; fails because of the : after gr which causes a PHP error. I could figure out how to get the element, so thought I would change the name using the code below but it throws the following error Warning: simplexml_load_file() [function.simplexml-load-file]: I/O warning : failed to load external entity "<?xml version="1.0"?><feed xmlns:idx="urn:atom-extension:indexing" xmlns:media="http://search.yahoo.com/mrss/" xmlns <?php $get_feed = file_get_contents('http://www.google.com/reader/public/atom/user/03120403612393553979/state/com.google/broadcast'); $old = "gr:crawl-timestamp-msec"; $new = "timestamp"; $xml_file = str_replace($old, $new, $get_feed); $xml = simplexml_load_file($xml_file); $i = 0; foreach ($xml->entry as $value) { $id = $xml->entry[$i]->id; $date = date('Y-m-d H:i:s', strtotime($xml->entry[$i]->attributes()->timestamp )); $text = $xml->entry[$i]->title; $link = $xml->entry[$i]->link->attributes()->href; $source = "googleshared"; echo "date = $date<br />"; $sql="INSERT IGNORE INTO timeline (id,date,text,link, source) VALUES ('$id', '$date', '$text', '$link', '$source')"; mysql_query($sql); $i++; }` Could someone point me in the right direction please. Cheers Craig

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  • ActiveX control loading but not activating correctly (only when using in Reg Free COM)

    - by embnut
    I have an ActiveX control (created using C#) that I am adding to a form in Visual FoxPro using late binding. It works without problems when I register the control. I want to use reg free COM and created necessary manifest files. Now it load and displays in an inactive state until I double click or programatically activate it. I don't think it has anything to do with the reg free com manifest files. However is there something I need to do to set it up before/after making the late binding call AddObject()? this.AddObject('OleControl1', 'oleControl', 'SomeCompany.SomeOleControl') When I check the OleTypeAllowed Property of the OleControl created by AddObject() it is 1 (Embedded OLE object) instead of -2 (ActiveX object). So the OleControl got instantiated to the wrong type. I also tried the following: DEFINE(d) a subclass of OleControl and set the property OleTypeAllowed = -2. Used late binding to load the control. It did not work as required. The OleTypeAllowed came back as 1 Registered the ActiveX control. Added the ActiveX control to the project as a subclass using the visual editor. Unregistered the control. Used late binding to load the control. It did not work as required. The OleTypeAllowed came back as 1. Is it possible to load the OleControl as a ActiveX control? Any input from VB that I can convert to FoxPro would also be appreciated.

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  • ASP Classic, SQL 2008, XML Output, and DSN vs DSN-Less Produces Chinese Letters

    - by RoLYroLLs
    I've been having a problem for the past month and can't seem to figure out what is wrong. Here's the setup and a little background. Background: I have a web-host who was running my website on Windows Server 2003 and SQL Server 2000. One of my webpages returned a result set from a stored procedure from the SQL server as xml. Below is the code: Stored Procedure: select top 10 1 as tag , null as parent , column1 as [item!1!column1!element] , column2 as [item!1!column2!element] from table1 for XML EXPLICIT ASP Page: index.asp Call OpenConn Set cmd = Server.CreateObject("ADODB.Command") With cmd .ActiveConnection = dbc .CommandText = "name of proc" .CommandType = adCmdStoredProc .Parameters.Append .CreateParameter("@RetVal", adInteger, adParamReturnValue, 4) .Parameters.Append .CreateParameter("@Level", adInteger, adParamInput, 4, Level) End With Set rsItems = Server.CreateObject("ADODB.Recordset") With rsItems .CursorLocation = adUseClient .CursorType = adOpenStatic .LockType = adLockBatchOptimistic Set .Source = cmd .Open Set .ActiveConnection = Nothing End With If NOT rsItems.BOF AND NOT rsItems.EOF Then OutputXMLQueryResults rsItems,"items" End If Set rsItems = Nothing Set cmd = Nothing Call CloseConn Sub OpenConn() strConn = "Provider=SQLOLEDB;Data Source=[hidden];User Id=[hidden];Password=[hidden];Initial Catalog=[hidden];" Set dbc = Server.CreateObject("ADODB.Connection") dbc.open strConn End Sub Sub CloseConn() If IsObject(dbc) Then If dbc.State = adStateOpen Then dbc.Close End If Set dbc = Nothing End If End Sub Sub OutputXMLQueryResults(RS,RootElementName) Response.Clear Response.ContentType = "text/xml" Response.Codepage = 65001 Response.Charset = "utf-8" Response.Write "" Response.Write "" While Not RS.EOF Response.Write RS(0).Value RS.MoveNext WEnd Response.Write "" Response.End End Sub Present: All was working great, until my host upgraded to Windows Server 2008 and SQL Server 2008. All of the sudden I was getting results like this: From Browser: From View Source: However, I found that if I use a DSN connection strConn = "DSN=[my DSN Name];User Id=[hidden];Password=[hidden];Initial Catalog=[hidden];" it works perfectly fine! My current host is not going to support DSN any longer, but that's out of scope for this issue. Someone told me to use an ADO.Stream object instead of a Recordset object, but I'm unsure how to implement that. Question: Has anyone run into this and found a way to fix it? What about that ADO.Stream object, can someone help me with a sample that would fit my code?

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  • Javascript redeclared global variable overrides old value

    - by Yousuf Haider
    I ran into an interesting issue the other day and was wondering if someone could shed light on why this is happening. Here is what I am doing (for the purposes of this example I have dumbed down the example somewhat): I am creating a globally scoped variable using the square bracket notation and assigning it a value. Later I declare a var with the same name as the one I just created above. Note I am not assigning a value. Since this is a redeclaration of the same variable the old value should not be overriden as described here: http://www.w3schools.com/js/js_variables.asp //create global variable with square bracket notation window['y'] = 'old'; //redeclaration of the same variable var y; if (!y) y = 'new'; alert(y); //shows New instead of Old The problem is that the old value actually does get overriden and in the above eg. the alert shows 'new' instead of 'old'. Why ? I guess another way to state my question is how is the above code different in terms of semantics from the code below: //create global variable var y = 'old'; //redeclaration of the same variable var y; if (!y) y = 'new'; alert(y); //shows Old

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  • PCA extended face recognition

    - by cMinor
    The state of the art says that we can use PCA to perform face recognition. like this, this or this I am working with a project that involves training a classifier to detect a person who is wearing glasess or hats or even a mustache. The purpose of doing this is to detect when a person that has robbed a bank, store, or have commeted some sort of crime(s) (we have their image in a database), enters a certain place ( historically we know these guys have robbed, so we should take care to avoid problems). We came first to have a distributed database with all images of criminals, then I thought to have a layer of them clasifying these criminals using accesories like hats, mustache or anything that hides their face etc... Then, to apply that knowledge to detect when a particular or a suspect person enters a comercial place. ( In practice when someone is going to rob not all the times they are using an accesorie...) What do you think about this idea of doing PCA to first detect principal components of the face and then the components of an accesory. I was thinking that maybe a probabilistic approach is better so we can compute the probability the criminal is the person that entered a place and call the respective authorities.

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  • DDD and Client/Server apps

    - by Christophe Herreman
    I was wondering if any of you had successfully implemented DDD in a Client/Server app and would like to share some experiences. We are currently working on a smart client in Flex and a backend in Java. On the server we have a service layer exposed to the client that offers CRUD operations amongst some other service methods. I understand that in DDD these services should be repositories and services should be used to handle use cases that do not fit inside a repository. Right now, we mimic these services on the client behind an interface and inject implementations (Webservices, RMI, etc) via an IoC container. So some questions arise: should the server expose repositories to the client or do we need to have some sort of a facade (that is able to handle security for instance) should the client implement repositories (and DDD in general?) knowing that in the client, most of the logic is view related and real business logic lives on the server. All communication with the server happens asynchronously and we have a single threaded programming model on the client. how about mapping client to server objects and vice versa? We tried DTO's but reverted back to exposing the state of our objects and mapping directly to them. I know this is considered bad practice, but it saves us an incredible amount of time) In general I think a new generation of applications is coming with the growth of Flex, Silverlight, JavaFX and I'm curious how DDD fits into this.

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  • Why calling Process.killProcess(Process.myPid()) is a bad idea?

    - by Tal Kanel
    I've read some posts saying using this method is "not good", shouldn't been use, it's not the right way to "close" the application and it's not how android works... I understand and accept the fact that Android OS knows better then me when it's the right time to terminate the process, but I didn't heard yet a good explanation why it's wrong using the killProcess() method?. after all - it's part of the android API... what I do know is that calling this method while other threads doing in potential an important work (operations on files, writing to DB, HTTP requests, running services..) can be terminated in the middle, and it's clearly not good. also I know I can benefit from the fact that "re-open" the application will be faster, cause the system maybe still "holds" in memory state from last time been used, and killProcess() prevents that. beside this reason, in assumption I don't have such operations, and I don't care my application will load from scratch each run, there are other reasons why not using the killProcess() method? I know about finish() method to close an Activity, so don't write me about that please.. finish() is only for Activity. not to all application, and I think I know exactly why and when to use it... and another thing - I'm developing also games with the Unity3D framework, and exporting the project to android. when I decompiled the generated apk, I was very suprised to find out that the java source code created from unity - implementing Unity's - Application.quit() method, with Process.killProcess(Process.myPid()). Application.quit() is suppose to be the right way to close game according to Unity3d guides (is it really?? maybe I'm wrong, and missed something), so how it happens that the Unity's framework developers which doing a very good work as it seems implemented this in native android to killProcess()? anyway - I wish to have a "list of reasons" why not using the killProcess() method, so please write down your answer - if you have something interesting to say about that. TIA

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  • Alternative to jQuery's .toggle() method that supports eventData?

    - by Bungle
    The jQuery documentation for the .toggle() method states: The .toggle() method is provided for convenience. It is relatively straightforward to implement the same behavior by hand, and this can be necessary if the assumptions built into .toggle() prove limiting. The assumptions built into .toggle have proven limiting for my current task, but the documentation doesn't elaborate on how to implement the same behavior. I need to pass eventData to the handler functions provided to toggle(), but it appears that only .bind() will support this, not .toggle(). My first inclination is to use a flag global to a single handler function to store the click state. In other words, rather than: $('a').toggle(function() { alert('odd number of clicks'); }, function() { alert('even number of clicks'); }); do this: var clicks = true; $('a').click(function() { if (clicks) { alert('odd number of clicks'); clicks = false; } else { alert('even number of clicks'); clicks = true; } }); I haven't tested the latter, but I suspect it would work. Is this the best way to do something like this, or is there a better way that I'm missing? Thanks!

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  • detecting pauses in a spoken word audio file using pymad, pcm, vad, etc

    - by james
    First I am going to broadly state what I'm trying to do and ask for advice. Then I will explain my current approach and ask for answers to my current problems. Problem I have an MP3 file of a person speaking. I'd like to split it up into segments roughly corresponding to a sentence or phrase. (I'd do it manually, but we are talking hours of data.) If you have advice on how to do this programatically or for some existing utilities, I'd love to hear it. (I'm aware of voice activity detection and I've looked into it a bit, but I didn't see any freely available utilities.) Current Approach I thought the simplest thing would be to scan the MP3 at certain intervals and identify places where the average volume was below some threshold. Then I would use some existing utility to cut up the mp3 at those locations. I've been playing around with pymad and I believe that I've successfully extracted the PCM (pulse code modulation) data for each frame of the mp3. Now I am stuck because I can't really seem to wrap my head around how the PCM data translates to relative volume. I'm also aware of other complicating factors like multiple channels, big endian vs little, etc. Advice on how to map a group of pcm samples to relative volume would be key. Thanks!

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  • What are alternatives to Win32 PulseEvent() function?

    - by Bill
    The documentation for the Win32 API PulseEvent() function (kernel32.dll) states that this function is “… unreliable and should not be used by new applications. Instead, use condition variables”. However, condition variables cannot be used across process boundaries like (named) events can. I have a scenario that is cross-process, cross-runtime (native and managed code) in which a single producer occasionally has something interesting to make known to zero or more consumers. Right now, a well-known named event is used (and set to signaled state) by the producer using this PulseEvent function when it needs to make something known. Zero or more consumers wait on that event (WaitForSingleObject()) and perform an action in response. There is no need for two-way communication in my scenario, and the producer does not need to know if the event has any listeners, nor does it need to know if the event was successfully acted upon. On the other hand, I do not want any consumers to ever miss any events. In other words, the system needs to be perfectly reliable – but the producer does not need to know if that is the case or not. The scenario can be thought of as a “clock ticker” – i.e., the producer provides a semi-regular signal for zero or more consumers to count. And all consumers must have the correct count over any given period of time. No polling by consumers is allowed (performance reasons). The ticker is just a few milliseconds (20 or so, but not perfectly regular). Raymen Chen (The Old New Thing) has a blog post pointing out the “fundamentally flawed” nature of the PulseEvent() function, but I do not see an alternative for my scenario from Chen or the posted comments. Can anyone please suggest one? Please keep in mind that the IPC signal must cross process boundries on the machine, not simply threads. And the solution needs to have high performance in that consumers must be able to act within 10ms of each event.

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  • TLS with SNI in Java clients

    - by ftrotter
    There is an ongoing discussion on the security and trust working group for NHIN Direct regarding the IP-to-domain mapping problem that is created with traditional SSL. If an HISP (as defined by NHIN Direct) wants to host thousands of NHIN Direct "Health Domains" for providers, then it will an "artificially inflated cost" to have to purchase an IP for each of those domains. Because Apache and OpenSSL have recently released TLS with support for the SNI extension, it is possible to use SNI as a solution to this problem on the server side. However, if we decide that we will allow server implementations of the NHINDirect transport layer to support TLS+SNI, then we must require that all clients support SNI too. OpenSSL based clients should do this by default and one could always us stunnel to implement an TLS+SNI aware client to proxy if your given programming language SSL implementation does not support SNI. It appears that native Java applications using OpenJDK do not yet support SNI, but I cannot get a straight answer out of that project. I know that there are OpenSSL Java libraries available but I have no idea if that would be considered viable. Can you give me a "state of the art" summary of where TLS+SNI support is for Java clients? I need a Java implementers perspective on this.

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  • Long running stateful service in .NET

    - by Asaf R
    Hi, I need to create a service in .NET that maintains (inner) state in-memory, spawns multiple threads and is generally long-running. There are a lot options - Good-old Windows Service Windows Communication Services Windows Workflow Foundation I really don't know which to choose. Most of the functionality is in a library used by this service, so the service itself is rather simple. On one hand, it's important the service host is as close to "simply working" as possible, which excludes Windows Service. On the other hand, it's important that the service is not taken down by the host just because there's no external activity, which makes WCF kind o' "scary". As for WF, it's strongest selling point is the ability to create processes as, um..., workflows, which is something I don't need nor want. To sum it up, the plethora of Microsoft technologies got me a bit confused. I'd appreciate help regarding the pros and cons of each solution (or other's I've failed to mention) for the problem of a stateful, long running service in .NET Thanks, Asaf P.S., I'm using .NET 4. EDIT: What I mean by the host "simply working" is, for example, that the service I create be reactivated if it crashes. I guess the reason for this question is that I've created Windows Services in the past (I think it was in plain C++ with Win32 API), and I don't want to miss out on something simpler if there's is such as thing. Thanks for all the replies thus far! Asaf.

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  • When I add a database table to a DBML file via LINQ to SQL, I get a slew of compiler errors.

    - by Zian Choy
    Whenever I add a certain table to a DBML file via LINQ to SQL, I get 102 errors in my VB NET project. Some of the errors: Error 1 Attribute 'TableAttribute' cannot be applied multiple times. C:\Documents and Settings\zchoy\My Documents\Virtual EMS Deployment\Life And Death\Life And Death\ShearwaterEMS.designer.vb 74 2 EMS Reality Check Error 2 'emptyChangingEventArgs' is already declared as 'Private Shared emptyChangingEventArgs As System.ComponentModel.PropertyChangingEventArgs' in this class. C:\Documents and Settings\zchoy\My Documents\Virtual EMS Deployment\Life And Death\Life And Death\ShearwaterEMS.designer.vb 78 17 EMS Reality Check Error 3 '_GroupID' is already declared as 'Private _GroupID As Integer' in this class. C:\Documents and Settings\zchoy\My Documents\Virtual EMS Deployment\Life And Death\Life And Death\ShearwaterEMS.designer.vb 80 10 EMS Reality Check Error 4 '_ID' is already declared as 'Private _ID As Integer' in this class. C:\Documents and Settings\zchoy\My Documents\Virtual EMS Deployment\Life And Death\Life And Death\ShearwaterEMS.designer.vb 82 10 EMS Reality Check Any suggestions for getting the table to work with LINQ to SQL will be welcomed. The table's properties: Group ID ID (Primary Key) Contact Title UseGroupAddress InternationalFormat Address1 Address2 City State ZipCode Country Phone Fax EMailAddress Notes DateAdded AddedBy DateChanged ChangedBy Active ExternalReference ChangeCounter PhoneLabel FaxLabel

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  • Entity Framework with ASP.NET MVC. Updating entity problem

    - by Kitaly
    Hi people. I'm trying to update an entity and its related entities as well. For instance, I have a class Car with a property Category and I want to change its Category. So, I have the following methods in the Controller: public ActionResult Edit(int id) { var categories = context.Categories.ToList(); ViewData["categories"] = new SelectList(categories, "Id", "Name"); var car = context.Cars.Where(c => c.Id == id).First(); return PartialView("Form", car); } [AcceptVerbs(HttpVerbs.Post)] public ActionResult Edit(Car car) { var category = context.Categories.Where(c => c.Id == car.Category.Id).First(); car.Category = category; context.UpdateCar(car); context.SaveChanges(); return RedirectToAction("Index"); } The UpdateCar method, in ObjectContext class, follows: public void UpdateCar(Car car) { var attachedCar = Cars.Where(c => c.Id == car.Id).First(); ApplyItemUpdates(attachedCar, car); } private void ApplyItemUpdates(EntityObject originalItem, EntityObject updatedItem) { try { ApplyPropertyChanges(originalItem.EntityKey.EntitySetName, updatedItem); ApplyReferencePropertyChanges(updatedItem, originalItem); } catch (InvalidOperationException ex) { Console.WriteLine(ex.ToString()); } } public void ApplyReferencePropertyChanges(IEntityWithRelationships newEntity, IEntityWithRelationships oldEntity) { foreach (var relatedEnd in oldEntity.RelationshipManager.GetAllRelatedEnds()) { var oldRef = relatedEnd as EntityReference; if (oldRef != null) { var newRef = newEntity.RelationshipManager.GetRelatedEnd(oldRef.RelationshipName, oldRef.TargetRoleName) as EntityReference; oldRef.EntityKey = newRef.EntityKey; } } } The problem is that when I set the Category property after the POST in my controller, the entity state changes to Added instead of remaining as Detached. How can I update one-to-one relationship with Entity Framework and ASP.NET MVC without setting all the properties, one by one like this post?

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  • Workflow engine BPMN, Drools, etc or ESB?

    - by Tom
    We currently have an application that is based on an in-house developed workflow engine with YAML based DSL. We are looking to move parts of it to Java. I have discovered a number of java solutions like Intalio, JBPM, Drools Expert, Drools Flow etc. They appear to be aimed at businesses where the business analyst creates the workflows using a graphical editor and submits them to the workflow engine. They seem geared towards ease of use for non-technical people rather than for developers with a focus on human interaction. The workflows tend to look like. Discover-a-file -\ -> join -> process-file -> move-file -> register-file Discover-some-metadata -/ If any step fails we need to retry it X times. We also need to be able to stop the system and be able to restart it and have it continue from where it was (durable). Some of our workflows can be defined by a set of goals we need to achieve so Jess's backwards rule chaining sounds interesting but it is not open source. It might be that what we are after is a Finite State Machine engine or just an Enterprise Service Bus and do everything as JMS queues. Is there a good open source workflow engine that is both standards-based but also geared towards developers. We don't particular want to use a graphical workflow designer or write reams of XML and it should ideally be in Java or language agnostic (makes REST/Soap calls to external services). Thanks, Tom

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  • postgresql error - ERROR: input is out of range

    - by CaffeineIV
    The function below keeps returning this error message. I thought that maybe the double_precision field type was what was causing this, and I tried to use CAST, but either that's not it, or I didn't do it right... Help? Here's the error: ERROR: input is out of range CONTEXT: PL/pgSQL function "calculate_distance" line 7 at RETURN ********** Error ********** ERROR: input is out of range SQL state: 22003 Context: PL/pgSQL function "calculate_distance" line 7 at RETURN And here's the function: CREATE OR REPLACE FUNCTION calculate_distance(character varying, double precision, double precision, double precision, double precision) RETURNS double precision AS $BODY$ DECLARE earth_radius double precision; BEGIN earth_radius := 3959.0; RETURN earth_radius * acos(sin($2 / 57.2958) * sin($4 / 57.2958) + cos($2/ 57.2958) * cos($4 / 57.2958) * cos(($5 / 57.2958) - ($3 / 57.2958))); END; $BODY$ LANGUAGE 'plpgsql' VOLATILE COST 100; ALTER FUNCTION calculate_distance(character varying, double precision, double precision, double precision, double precision) OWNER TO postgres; //I tried changing (unsuccessfully) that RETURN line to: RETURN CAST( (earth_radius * acos(sin($2 / 57.2958) * sin($4 / 57.2958) + cos($2/ 57.2958) * cos($4 / 57.2958) * cos(($5 / 57.2958) - ($3 / 57.2958))) ) AS text);

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