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• Neural Network with softmax activation

  - by Cambium

  This is more or less a research project for a course, and my understanding of NN is very/fairly limited, so please be patient :) ============== I am currently in the process of building a neural network that attempts to examine an input dataset and output the probability/likelihood of each classification (there are 5 different classifications). Naturally, the sum of all output nodes should add up to 1. Currently, I have two layers, and I set the hidden layer to contain 10 nodes. I came up with two different types of implementations 1) Logistic sigmoid for hidden layer activation, softmax for output activation 2) Softmax for both hidden layer and output activation I am using gradient descent to find local maximums in order to adjust the hidden nodes' weights and the output nodes' weights. I am certain in that I have this correct for sigmoid. I am less certain with softmax (or whether I can use gradient descent at all), after a bit of researching, I couldn't find the answer and decided to compute the derivative myself and obtained softmax'(x) = softmax(x) - softmax(x)^2 (this returns an column vector of size n). I have also looked into the MATLAB NN toolkit, the derivative of softmax provided by the toolkit returned a square matrix of size nxn, where the diagonal coincides with the softmax'(x) that I calculated by hand; and I am not sure how to interpret the output matrix. I ran each implementation with a learning rate of 0.001 and 1000 iterations of back propagation. However, my NN returns 0.2 (an even distribution) for all five output nodes, for any subset of the input dataset. My conclusions: o I am fairly certain that my gradient of descent is incorrectly done, but I have no idea how to fix this. o Perhaps I am not using enough hidden nodes o Perhaps I should increase the number of layers Any help would be greatly appreciated! The dataset I am working with can be found here (processed Cleveland): http://archive.ics.uci.edu/ml/datasets/Heart+Disease

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• WCF Callback Contract InvalidOperationException: Collection has been modified

  - by mrlane

  We are using a WCF service with a Callback contract. Communication is Asynchronous. The service contract is defined as: [ServiceContract(Namespace = "Silverlight", CallbackContract = typeof(ISessionClient),SessionMode = SessionMode.Allowed)] public interface ISessionService With a method: [OperationContract(IsOneWay = true)] void Send(Message message); The callback contract is defined as [ServiceContract] public interface ISessionClient With methods: [OperationContract(IsOneWay = true, AsyncPattern = true)] IAsyncResult BeginSend(Message message, AsyncCallback callback, object state); void EndSend(IAsyncResult result); The implementation of BeginSend and EndSend in the callback channel are as follows: public void Send(ActionMessage actionMessage) { Message message = Message.CreateMessage(_messageVersion, CommsSettings.SOAPActionReceive, actionMessage, _messageSerializer); lock (LO_backChannel) { try { _backChannel.BeginSend(message, OnSendComplete, null); } catch (Exception ex) { _hasFaulted = true; } } } private void OnSendComplete(IAsyncResult asyncResult) { lock (LO_backChannel) { try { _backChannel.EndSend(asyncResult); } catch (Exception ex) { _hasFaulted = true; } } } We are getting an InvalidOperationException: "Collection has been modified" on _backChannel.EndSend(asyncResult) seemingly randomly, and we are really out of ideas about what is causing this. I understand what the exception means, and that concurrency issues are a common cause of such exceptions (hence the locks), but it really doesn't make any sense to me in this situation. The clients of our service are Silverlight 3.0 clients using PollingDuplexHttpBinding which is the only binding available for Silverlight. We have been running fine for ages, but recently have been doing a lot of data binding, and this is when the issues started. Any help with this is appreciated as I am personally stumped at this time.

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• Spring and hibernate.cfg.xml

  - by Steve Kuo

  How do I get Spring to load Hibernate's properties from hibernate.cfg.xml? We're using Spring and JPA (with Hibernate as the implementation). Spring's applicationContext.xml specifies the JPA dialect and Hibernate properties: <bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalEntityManagerFactoryBean"> <property name="jpaDialect"> <bean class="org.springframework.orm.jpa.vendor.HibernateJpaDialect" /> </property> <property name="jpaProperties"> <props> <prop key="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</prop> </props> </property> </bean> In this configuration, Spring is reading all the Hibernate properties via applicationContext.xml . When I create a hibernate.cfg.xml (located at the root of my classpath, the same level as META-INF), Hibernate doesn't read it at all (it's completely ignored). What I'm trying to do is configure Hibernate second level cache by inserting the cache properties in hibernate.cfg.xml: <cache usage="transactional|read-write|nonstrict-read-write|read-only" region="RegionName" include="all|non-lazy" />

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• How to count term frequency for set of documents?

  - by ManBugra

  i have a Lucene-Index with following documents: doc1 := { caldari, jita, shield, planet } doc2 := { gallente, dodixie, armor, planet } doc3 := { amarr, laser, armor, planet } doc4 := { minmatar, rens, space } doc5 := { jove, space, secret, planet } so these 5 documents use 14 different terms: [ caldari, jita, shield, planet, gallente, dodixie, armor, amarr, laser, minmatar, rens, jove, space, secret ] the frequency of each term: [ 1, 1, 1, 4, 1, 1, 2, 1, 1, 1, 1, 1, 2, 1 ] for easy reading: [ caldari:1, jita:1, shield:1, planet:4, gallente:1, dodixie:1, armor:2, amarr:1, laser:1, minmatar:1, rens:1, jove:1, space:2, secret:1 ] What i do want to know now is, how to obtain the term frequency vector for a set of documents? for example: Set<Documents> docs := [ doc2, doc3 ] termFrequencies = magicFunction(docs); System.out.pring( termFrequencies ); would result in the ouput: [ caldari:0, jita:0, shield:0, planet:2, gallente:1, dodixie:1, armor:2, amarr:1, laser:1, minmatar:0, rens:0, jove:0, space:0, secret:0 ] remove all zeros: [ planet:2, gallente:1, dodixie:1, armor:2, amarr:1, laser:1 ] Notice, that the result vetor contains only the term frequencies of the set of documents. NOT the overall frequencies of the whole index! The term 'planet' is present 4 times in the whole index but the source set of documents only contains it 2 times. A naive implementation would be to just iterate over all documents in the docs set, create a map and count each term. But i need a solution that would also work with a document set size of 100.000 or 500.000. Is there a feature in Lucene i can use to obtain this term vector? If there is no such feature, how would a data structure look like someone can create at index time to obtain such a term vector easily and fast? I'm not that Lucene expert so i'am sorry if the solution is obvious or trivial.

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• Random point on VideoDisplay isn't accurate enough

  - by Mike

  For a schoolassigment me and some buddies of mine are creating an application that is showing many similarities with the C-Mon & Kypski musicvideo on www.oneframeoffame.com. The application is being developed in Flex. We want to get a random point of a clip, let it pause so a user can mimic the pose and make a snapshot out of it. What i managed to do is get a random point of the movie. I did this by getting a random value between 0 and de total duration of the movie. But what i didn't managed to do is let the screen pause on every 24st of a frame. As the movie concist out of 24FPS. It looks like the the random value of the movie that is being requested is being rounded by the movie itself. As example: There appears to be no difference between the frames requested at 2.40 or 2.41. It appears it got something to do with keyframing i've read on the Adobe® Flex™ 3.5 Language Reference. The movie is a FLV file and i use the VideoDisplay object to display the movie. Does someone is familiar with this or knows a solution to my problem? Thanks in advance

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• what exactly is the danger of an uninitialized pointer in C

  - by akh2103

  I am trying get a handle on C as I work my way thru Jim Trevor's "Cyclone: A safe dialect of C" for a PL class. Trevor and his co-authors are trying to make a safe version of C, so they eliminate uninitialized pointers in their language. Googling around a bit on uninitialized pointers, it seems like un-initialized pointers point to random locations in memory. It seems like this alone makes them unsafe. If you reference an un-itilialized pointer, you jump to an unsafe part of memory. Period. But the way Trevor talks about them seems to imply that it is more complex. He cites the following code, and explains that when the function FrmGetObjectIndex dereferences f, it isn’t accessing a valid pointer, but rather an unpredictable address — whatever was on the stack when the space for f was allocated. What does Trevor mean by "whatever was on the stack when the space for f was allocated"? Are "un-initialized" pointers initialized to random locations in memory by default? Or does their "random" behavior have to do with the memory allocated for these pointers getting filled with strange values (that are then referenced) because of unexpected behavior on the stack. Form *f; switch (event->eType) { case frmOpenEvent: f = FrmGetActiveForm(); ... case ctlSelectEvent: i = FrmGetObjectIndex(f, field); ... }

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• Resolving Circular References for Objects Implementing ISerializable

  - by Chris

  I'm writing my own IFormatter implementation and I cannot think of a way to resolve circular references between two types that both implement ISerializable. Here's the usual pattern: [Serializable] class Foo : ISerializable { private Bar m_bar; public Foo(Bar bar) { m_bar = bar; m_bar.Foo = this; } public Bar Bar { get { return m_bar; } } protected Foo(SerializationInfo info, StreamingContext context) { m_bar = (Bar)info.GetValue("1", typeof(Bar)); } public void GetObjectData(SerializationInfo info, StreamingContext context) { info.AddValue("1", m_bar); } } [Serializable] class Bar : ISerializable { private Foo m_foo; public Foo Foo { get { return m_foo; } set { m_foo = value; } } public Bar() { } protected Bar(SerializationInfo info, StreamingContext context) { m_foo = (Foo)info.GetValue("1", typeof(Foo)); } public void GetObjectData(SerializationInfo info, StreamingContext context) { info.AddValue("1", m_foo); } } I then do this: Bar b = new Bar(); Foo f = new Foo(b); bool equal = ReferenceEquals(b, b.Foo.Bar); // true // Serialise and deserialise b equal = ReferenceEquals(b, b.Foo.Bar); If I use an out-of-the-box BinaryFormatter to serialise and deserialise b, the above test for reference-equality returns true as one would expect. But I cannot conceive of a way to achieve this in my custom IFormatter. In a non-ISerializable situation I can simply revisit "pending" object fields using reflection once the target references have been resolved. But for objects implementing ISerializable it is not possible to inject new data using SerializationInfo. Can anyone point me in the right direction?

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• How to scan an array for certain information

  - by Andrew Martin

  I've been doing an MSc Software Development conversion course, the main language of which is Java, since the end of September. We have our first assessed practical coming and I was hoping for some guidance. We have to create an array that will store 100 integers (all of which are between 1 and 10), which are generated by a random number generator, and then print out ten numbers of this array per line. For the second part, we need to scan these integers, count up how often each number appears and store the results in a second array. I've done the first bit okay, but I'm confused about how to do the second. I have been looking through the scanner class to see if it has any methods which I could use, but I don't see any. Could anyone point me in the right direction - not the answer, but perhaps which library it comes from? Code so far: import java.util.Random; public class Practical4_Assessed { public static void main(String[] args) { Random numberGenerator = new Random (); int[] arrayOfGenerator = new int[100]; for (int countOfGenerator = 0; countOfGenerator < 100; countOfGenerator++) arrayOfGenerator[countOfGenerator] = numberGenerator.nextInt(10); int countOfNumbersOnLine = 0; for (int countOfOutput = 0; countOfOutput < 100; countOfOutput++) { if (countOfNumbersOnLine == 10) { System.out.println(""); countOfNumbersOnLine = 0; countOfOutput--; } else { System.out.print(arrayOfGenerator[countOfOutput] + " "); countOfNumbersOnLine++; } } } } Thanks, Andrew

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• Go: using a pointer to array

  - by Sean

  I'm having a little play with google's Go language, and I've run into something which is fairly basic in C but doesn't seem to be covered in the documentation I've seen so far When I pass a pointer to an array to a function, I presumed we'd have some way to access it as follows: func conv(x []int, xlen int, h []int, hlen int, y *[]int) for i := 0; i<xlen; i++ { for j := 0; j<hlen; j++ { *y[i+j] += x[i]*h[j] } } } But the Go compiler doesn't like this: sean@spray:~/dev$ 8g broke.go broke.go:8: invalid operation: y[i + j] (index of type *[]int) Fair enough - it was just a guess. I have got a fairly straightforward workaround: func conv(x []int, xlen int, h []int, hlen int, y_ *[]int) { y := *y_ for i := 0; i<xlen; i++ { for j := 0; j<hlen; j++ { y[i+j] += x[i]*h[j] } } } But surely there's a better way. The annoying thing is that googling for info on Go isn't very useful as all sorts of C\C++\unrelated results appear for most search terms.

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• Use Objective-C without NSObject?

  - by Alex I

  I am testing some simple Objective-C code on Windows (cygwin, gcc). This code already works in Xcode on Mac. I would like to convert my objects to not subclass NSObject (or anything else, lol). Is this possible, and how? What I have so far: // MyObject.h @interface MyObject - (void)myMethod:(int) param; @end and // MyObject.m #include "MyObject.h" @interface MyObject() { // this line is a syntax error, why? int _field; } @end @implementation MyObject - (id)init { // what goes in here? return self; } - (void)myMethod:(int) param { _field = param; } @end What happens when I try compiling it: gcc -o test MyObject.m -lobjc MyObject.m:4:1: error: expected identifier or ‘(’ before ‘{’ token MyObject.m: In function ‘-[MyObject myMethod:]’: MyObject.m:17:3: error: ‘_field’ undeclared (first use in this function) EDIT My compiler is cygwin's gcc, also has cygwin gcc-objc package: gcc --version gcc (GCC) 4.7.3 I have tried looking for this online and in a couple of Objective-C tutorials, but every example of a class I have found inherits from NSObject. Is it really impossible to write Objective-C without Cocoa or some kind of Cocoa replacement that provides NSObject? (Yes, I know about GNUstep. I would really rather avoid that if possible...)

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• Create dynamic factory method in PHP (< 5.3)

  - by fireeyedboy

  How would one typically create a dynamic factory method in PHP? By dynamic factory method, I mean a factory method that will autodiscover what objects there are to create, based on some aspect of the given argument. Preferably without registering them first with the factory either. I'm OK with having the possible objects be placed in one common place (a directory) though. I want to avoid your typical switch statement in the factory method, such as this: public static function factory( $someObject ) { $className = get_class( $someObject ); switch( $className ) { case 'Foo': return new FooRelatedObject(); break; case 'Bar': return new BarRelatedObject(); break; // etc... } } My specific case deals with the factory creating a voting repository based on the item to vote for. The items all implement a Voteable interface. Something like this: Default_User implements Voteable ... Default_Comment implements Voteable ... Default_Event implements Voteable ... Default_VoteRepositoryFactory { public static function factory( Voteable $item ) { // autodiscover what type of repository this item needs // for instance, Default_User needs a Default_VoteRepository_User // etc... return new Default_VoteRepository_OfSomeType(); } } I want to be able to drop in new Voteable items and Vote repositories for these items, without touching the implementation of the factory.

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• Creating form using Generic_inlineformset_factory from the Model Form

  - by Prateek

  hello dear all, I wanted to create a edit form with the help of ModelForm. and my models contain a Generic relation b/w classes, so if any one could suggest me the view and a bit of template for the purpose I would be very thankful, as I am new to the language. My models look like:- class Employee(Person): nickname = models.CharField(_('nickname'), max_length=25, null=True, blank=True) blood_type = models.CharField(_('blood group'), max_length=3, null=True, blank=True, choices=BLOOD_TYPE_CHOICES) marital_status = models.CharField(_('marital status'), max_length=1, null=True, blank=True, choices=MARITAL_STATUS_CHOICES) nationality = CountryField(_('nationality'), default='IN', null=True, blank=True) about = models.TextField(_('about'), blank=True, null=True) dependent = models.ManyToManyField(Dependent, through='DependentRelationship') pan_card_number = models.CharField(_('PAN card number'), max_length=50, blank=True, null=True) policy_number = models.CharField(_('policy number'), max_length=50, null=True, blank=True) # code specific details user = models.OneToOneField(User, blank=True, null=True, verbose_name=_('user')) class Person(models.Model): """Person model""" title = models.CharField(_('title'), max_length=20, null=True, blank=True) first_name = models.CharField(_('first name'), max_length=100) middle_name = models.CharField(_('middle name'), max_length=100, null=True, blank=True) last_name = models.CharField(_('last name'), max_length=100, null=True, blank=True) suffix = models.CharField(_('suffix'), max_length=20, null=True, blank=True) slug = models.SlugField(_('slug'), max_length=50, unique=True) class PhoneNumber(models.Model) : phone_number = generic.GenericRelation('PhoneNumber') email_address = generic.GenericRelation('EmailAddress') address = generic.GenericRelation('Address') date_of_birth = models.DateField(_('date of birth'), null=True, blank=True) gender = models.CharField(_('gender'), max_length=1, null=True, blank=True, choices=GENDER_CHOICES) content_type = models.ForeignKey(ContentType, If anyone could suggest me a link or so. it would be a great help........

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• Normalize whitespace and other plain-text formatting routines

  - by dreftymac

  Background: The language is JavaScript. The goal is to find a library or pre-existing code to do low-level plain-text formatting. I can write it myself, but why re-invent the wheel. The issue is: it is tough to determine if a "wheel" is out there, since any search for JavaScript libraries pulls up an ocean of HTML-centric stuff. I am not interested in HTML necessarily, just text. Example: I need a JavaScript function that changes this: BEFORE: nisi ut aliquip | ex ea commodo consequat duis |aute irure dolor in esse cillum dolore | eu fugiat nulla pariatur |excepteur sint occa in culpa qui | officia deserunt mollit anim id |est laborum ... into this ... AFTER: nisi ut aliquip | ex ea commodo consequat duis | aute irure dolor in esse cillum dolore | eu fugiat nulla pariatur | excepteur sint occa in culpa qui | officia deserunt mollit anim id | est laborum Question: Does it exist, a JavaScript library that is non-html-web-development-centric that has functions for normalizing spaces in delimited plain text, justifying and spacing plain text? Rationale: Investigating JavaScript for use in a programmer's text editor.

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• What issues to consider when rolling your own data-backend for Silverlight / AJAX on non-ASP.NET ser

  - by Edward Tanguay

  I have read-only Silverlight and AJAX apps which read static text and XML files from a PHP/Apache server, which works very nicely with features such as asynchronous loading, lazy-loading only what I need for each page, loading in the background, developed a little query language to get a PHP script to create custom XML files etc. it's pragmatic read-only REST, and all works fast and fine for read-only sites. Now I want to also add the ability to write data from these apps to a database on the same PHP/Apache server. For those of you who have built similar data-access layers, what do I need to consider while building this, especially regarding security so that not just any client can write and alter my database, e.g.: check HTTP_USER_AGENT for security check REMOTE_ADDR for security require a special code for security, perhaps a list of TAN codes (such as banks use for online transactions) each which can only be used once, both the client and server have these I wonder if there is some kind of standard REST query I should lean on for e.g. building SQL-like statements in the URL parameters, e.g. http://www.thedatalayersite.com/query?insertinto=customers&... Any thoughts, notes from experience, ideas, gotchas, especially ideas on tightening down security in this endeavor would be helpful.

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• Am I Writing Assembly Or NASM?

  - by cam

  I'm fed up with this. I've been trying to just get a grip on assembly for awhile, but I feel like I'm coding towards my compiler rather than a language. I've been using this tutorial, and so far it's giving me hell. I'm using NASM, which may be the problem, but I figured it was the most popular one. I'm simply trying to learn the most general form of assembly, so I decided to learn x86. I keep running into stupid errors, like not being able to increment a variable. Here's the latest one: not being able to use div. mov bx, 0; mov cx, 0; jmp start; start: inc cx; mov ax, cx; div 3; <-- invalid combination of opcode and operand cmp ah,0; jz totalvalue; mov ax, cx; div 5; <-- invalid combination of opcode and operand cmp ah, 0; jz totalvalue; cmp cx, 1000; jz end; totalvalue: add bx,cx; jmp start; jmp end; end: mov ah,4ch; mov al,00; int 21h; Should I change compilers? It seems like division should be standard. Do I need to read two tutorials (one on NASM, and one on x86?). Any specific help on this problem?

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• Writing fortran robust and "modern" code

  - by Blklight

  In some scientific environments, you often cannot go without FORTRAN as most of the developers only know that idiom, and there is lot of legacy code and related experience. And frankly, there are not many other cross-platform options for high performance programming ( C++ would do the task, but the syntax, zero-starting arrays, and pointers are too much for most engineers ;-) ). I'm a C++ guy but I'm stuck with some F90 projects. So, let's assume a new project must use FORTRAN (F90), but I want to build the most modern software architecture out of it. while being compatible with most "recent" compilers (intel ifort, but also including sun/HP/IBM own compilers) So I'm thinking of imposing: global variable forbidden, no gotos, no jump labels, "implicit none", etc. "object-oriented programming" (modules with datatypes + related subroutines) modular/reusable functions, well documented, reusable libraries assertions/preconditions/invariants (implemented using preprocessor statements) unit tests for all (most) subroutines and "objects" an intense "debug mode" (#ifdef DEBUG) with more checks and all possible Intel compiler checks possible (array bounds, subroutine interfaces, etc.) uniform and enforced legible coding style, using code processing tools C stubs/wrappers for libpthread, libDL (and eventually GPU kernels, etc.) C/C++ implementation of utility functions (strings, file operations, sockets, memory alloc/dealloc reference counting for debug mode, etc.) ( This may all seem "evident" modern programming assumptions, but in a legacy fortran world, most of these are big changes in the typical programmer workflow ) The goal with all that is to have trustworthy, maintainable and modular code. Whereas, in typical fortran, modularity is often not a primary goal, and code is trustworthy only if the original developer was very clever, and the code was not changed since then ! (i'm a bit joking here, but not much) I searched around for references about object-oriented fortran, programming-by-contract (assertions/preconditions/etc.), and found only ugly and outdated documents, syntaxes and papers done by people with no large-scale project involvement, and dead projects. Any good URL, advice, reference paper/books on the subject?

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• Why does my IMultiBindingConverter get an array of strings when used to set TextBox.Text?

  - by mcohen75

  Hi- I'm trying to use a MultiBinding with a converter where the child elements also have a converter. The XAML looks like so: <TextBlock> <TextBlock.Text> <MultiBinding Converter="{StaticResource localizedMessageConverter}" ConverterParameter="{x:Static res:Resources.RecordsFound}" > <Binding Converter="{StaticResource localizedMessageParameterConverter}" ConverterParameter="ALIAS" Path="Alias" Mode="OneWay" /> <Binding Converter="{StaticResource localizedMessageParameterConverter}" ConverterParameter="COUNT" Path="Count" Mode="OneWay" /> </MultiBinding> </TextBlock.Text> The problem I'm facing here is, whenever this is used with a TextBlock to specify the Text property, my IMultiValueConverter implementation gets an object collection of strings instead of the class returned by the IValueConverter. It seems that the ToString() method is called on the result of the inner converter and passed to the IMultiValueConverter. If used to specify the Content property of Label, all is well. It seems to me that the framework is assuming that the return type will be string, but why? I can see this for the MultiBinding since it should yield a result that is compatible with TextBlock.Text, but why would this also be the case for the Bindings inside a MultiBinding? If I remove the converter from the inner Binding elements, the native types are returned. In my case string and int.

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• Webbased data modelling and management tool

  - by pixeldude

  Is there a web-based tool available, where I am able to... ...define data models (like in a database admin tool) ...fill in data (in custom web forms, not too generic) with basic features like completion ...import data from CSV oder Excel Sheets ...export data to CSV or SQL ...create snapshots of my data models (versions, diff, etc.) ...share my data models ...discuss/collaborate with other people about my data models Well, I can develop something like this in PHP or with Ruby or whatever. But this is such a common task, where the application support could be a lot better. And it would be language and database independent. This would help to maintain data models in different versions and you can maybe share your data models with others, extend it with your team members, etc. There is a website called FreeBase, which allows you to define a data entity model and fill in data, which also has export features, but I need to define my own data model with my own granularity and structure. And it should not be shared in public if I don't want to. How do you solve problems like this yourself?

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• Objective C, Linking Error with extern variable..

  - by LCYSoft

  I have a very simple java code like this. I don't have any idea how to do this in Objective C. Especially, the static part which calls the getLocalAddress() method and assign it into the static string variable. I know how to set a static variable and a static method in Objective but I dont know how to implement that static { } part in java. Thanks in advance... public class Address { public static String localIpAddress; static { localIpAddress = getLocalIpAddress(); } public Address() { } static String getLocalIpAddress() { //do something to get local ip address } } I added this in my .h file #import <Foundation/Foundation.h> extern NSString *localIpAddress; @class WifiAddrss; @interface Address : NSObject { } @end And my .m file looks like #import "Address.h" #import "WifiAddress.h" @implementation Address +(void)initialize{ if(self == [Address class]){ localIpAddress = [self getLocalIpAddress]; } } +(NSString *)getLocalIpAddress{ return address here } -(id)init{ self = [super init]; if (self == nil){ NSLog(@"init error"); } return self; } @end And Now I am getting a linking error and it complains about "extern NSString *localIpAddress" part. If I change the extern to static, it works fine. But what I wanted to do is that I want make the scope of "localIpAddress" variable as grobal. Since if I put "static" in front of a variable in Objective-C then the variable is only visible in the class. But this time, I want to make that as a grobal variable. So my question is how to make "localIpAddress" variable as a grobal variable which is initialized once when the first time Address class is created.. Thanks in advance...

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• "do it all" page structure and things to watch out for?

  - by Andrew Heath

  I'm still getting my feet wet in PHP (my 1st language) and I've reached the competency level where I can code one page that handles all sorts of different related requests. They generally have a structure like this: (psuedo code) <?php include 'include/functions.php'; IF authorized IF submit (add data) ELSE IF update (update data) ELSE IF list (show special data) ELSE IF tab switch (show new area) ELSE display vanilla (show default) ELSE "must be registered/logged-in" ?> <HTML> // snip <?php echo $output; ?> // snip </HTML> and it all works nicely, and quite quickly which is cool. But I'm still sorta feeling my way in the dark... and would like some input from the pros regarding this type of page design... is it a good long-term structure? (it seems easily expanded...) are there security risks particular to this design? are there corners I should avoid painting myself into? Just curious about what lies ahead, really...

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• Simple imeplementation of admin/staff panel?

  - by Michael Mao

  Hi all: A new project requires a simple panel(page) for admin and staff members that : Preferably will not use SSL or any digital ceritification stuff, a simple login from via http will just be fine. has basic authentication which allows only admin to login as admin, and any staff member as of the group "staff". Ideally, the "credentials(username-hashedpassword pair)" will be stored in MySQL. is simple to configure if there is a package, or the strategy is simple to code. somewhere (PHP session?) somehow (include a script at the beginning of each page to check user group before doing anything?), it will detect any invalid user attempt to access protected page and redirect him/her to the login form. while still keeps high quality in security, something I worry about the most. Frankly I am having little knowledge about Internet security, and how modern CMS such as WordPress/Joomla do with their implementation in this. I only have one thing in my mind that I need to use a salt to hash the password (SHA1?) to make sure any hacker gets the username and password pair across the net cannot use that to log into the system. And that is what the client wants to make sure. But I really not sure where to start, any ideas? Thanks a lot in advance.

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• A map and set which uses contiguous memory and has a reserve function

  - by edA-qa mort-ora-y

  I use several maps and sets. The lack of contiguous memory, and high number of (de)allocations, is a performance bottleneck. I need a mainly STL-compatbile map and set class which can use a contiguous block of memory for internal objects (or multiple blocks). It also needs to have a reserve function so that I can preallocate for expected sizes. Before I write my own I'd like to check what is available first. Is there something in Boost which does this? Does somebody know of an available implementation elsewhere? Intrusive collection types are not usable here as the same objects need to exist in several collections. As far as I know STL memory pools are per-type, not per instance. These global pools are not efficient with respect to memory locality in mutli-cpu/core processing. Object pools don't work as the types will be shared between instance but their pool should not. In many cases a hash map may be an option in some cases.

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• Update a PDF to include an encrypted, hidden, unique identifier?

  - by Dave Jarvis

  Background The idea is this: Person provides contact information for online book purchase Book, as a PDF, is marked with a unique hash Person downloads book PDF passwords are annoying and extremely easy to circumvent. The ideal process would be something like: Generate hash based on contact information Store contact information and hash in database Acquire book lock Update an "include" file with hash text Generate book as PDF (using pdflatex) Apply hash to book Release book lock Send email with book download link Technologies The following technologies can be used (other programming languages are possible, but libraries will likely be limited to those supplied by the host): C, Java, PHP LaTeX files PDF files Linux Question What programming techniques (or open source software) should I investigate to: Embed a unique hash (or other mark) to a PDF Create a collusion-attack resistant mark Develop a non-fragile (e.g., PDF -> EPS -> PDF still contains the mark) solution Research I have looked at the following possibilities: Steganography Natural Language Processing (NLP) Convert blank pages in PDF to images; mark those images; reassemble PDF LaTeX watermark package ImageMagick Steganograhy requires keeping a master copy of the images, and I'm not sure if the watermark would survive PDF -> EPS -> PDF, or other types of conversion. LaTeX creates an image cache, so any steganographic process would have to intercept that process somehow. NLP introduces grammatical errors. Inserting blank pages as images is immediately suspect; it is easy to replace suspicious blank pages. The LaTeX watermark package draws visible marks. ImageMagick draws visible marks. What other solutions are possible? Related Links http://www.tcpdf.org/ invisible watermarks in images Thank you!

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• Problem consuming Exchange Web Service 2010 with jax-ws metro

  - by Johan Karlberg

  I am trying to consume the Exchange 2010 Web Service interface using JAX-WS. I'm using JAX-WS 2.2 RI (Metro 2.0). 2.1 exhibited the same problem. I am running into trouble with Exchange, which returns "HTTP/1.1 415 Cannot process the message because the content type 'text/xml;charset=utf-8' was not the expected type 'text/xml; charset=utf-8'." as a reponse (2.1 quoted the charset value, otherwise same response). Apparently I need to dictate the exact Content-type header for Exchange to be happy. Is there a way for me to do this without forcing me to manually rebuild the dependency? I currently rely on published maven artifacts, and would like to continue doing this if at all possible. The consuming process is a regular J2SE app, with no containers in sight. I have control of the application and can add pretty much anything required to the applications scope, but can not add out-of-process items like proxy servers. The client classes were generated from local WSDL, but the charset specification is derived from constants declared in the jaxws RI implementation, not the generated code. The resulting HTTP transport is thus handled by the standard http/https client from Sun JRE5 or JRE6.

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• RANDOM Number Generation in C

  - by CVS-2600Hertz-wordpress-com

  Recently i have begun development of a simple game. It is improved version of an earlier version that i had developed. Large part of the game's success depends on Random number generation in different modes: MODE1 - Truly Random mode myRand(min,max,mode=1); Should return me a random integer b/w min & max. MODE2 - Pseudo Random : Token out of a bag mode myRand(min,max,mode=2); Should return me a random integer b/w min & max. Also should internally keep track of the values returned and must not return the same value again until all the other values are returned atleast once. MODE3 - Pseudo Random : Human mode myRand(min,max,mode=3); Should return me a random integer b/w min & max. The randomisation ought to be not purely mathematically random, rather random as user perceive it. How Humans see RANDOM. * Assume the code is time-critical (i.e. any performance optimisations are welcome) * Pseudo-code will do but an implementation in C is what i'm looking for. * Please keep it simple. A single function should be sufficient (thats what i'm looking for) Thank You

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