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• How do you calculate expanding mean on time series using pandas?

  - by mlo

  How would you create a column(s) in the below pandas DataFrame where the new columns are the expanding mean/median of 'val' for each 'Mod_ID_x'. Imagine this as if were time series data and 'ID' 1-2 was on Day 1 and 'ID' 3-4 was on Day 2. I have tried every way I could think of but just can't seem to get it right. left4 = pd.DataFrame({'ID': [1,2,3,4],'val': [10000, 25000, 20000, 40000],'Mod_ID': [15, 35, 15, 42], 'car': ['ford','honda', 'ford', 'lexus']}) right4 = pd.DataFrame({'ID': [3,1,2,4],'color': ['red', 'green', 'blue', 'grey'], 'wheel': ['4wheel','4wheel', '2wheel', '2wheel'], 'Mod_ID': [15, 15, 35, 42]}) df1 = pd.merge(left4, right4, on='ID').drop('Mod_ID_y', axis=1)

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• Normalized Device Coordinates to window coordinates

  - by okoman

  I just read some stuff about the theory behind 3d graphics. As I understand it, normalized device coordinates (NDC) are coordinates that describe a point in the interval from -1 to 1 on both the horizontal and vertical axis. On the other hand window coordinates describe a point somewhere between (0,0) and (width,height) of the window. So my formula to convert a point from the NDC coordinate system to the window system would be xwin = width + xndc * 0.5 * width ywin = height + ynfv * 0.5 * height The problem now is that in the OpenGL documentation for glViewport there is an other formula: xwin = ( xndc + 1 ) * width * 0.5 + x ywin = ( yndc + 1 ) * height * 0.5 + y Now I'm wondering what I am getting wrong. Especially I'm wondering what the additional "x" and "y" mean. Hope the question isn't too "not programming related", but I thought somehow it is related to graphics programming.

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• ValueError: setting an array element with a sequence.

  - by MedicalMath

  This code: import numpy as p def firstfunction(): UnFilteredDuringExSummaryOfMeansArray = [] MeanOutputHeader=['TestID','ConditionName','FilterType','RRMean','HRMean','dZdtMaxVoltageMean','BZMean','ZXMean' ,'LVETMean','Z0Mean','StrokeVolumeMean','CardiacOutputMean','VelocityIndexMean'] dataMatrix = BeatByBeatMatrixOfMatrices[column] roughTrimmedMatrix = p.array(dataMatrix[1:,1:17]) trimmedMatrix = p.array(roughTrimmedMatrix,dtype=p.float64) myMeans = p.mean(trimmedMatrix,axis=0,dtype=p.float64) conditionMeansArray = [TestID,testCondition,'UnfilteredBefore',myMeans[3], myMeans[4], myMeans[6], myMeans[9] , myMeans[10], myMeans[11], myMeans[12], myMeans[13], myMeans[14], myMeans[15]] UnFilteredDuringExSummaryOfMeansArray.append(conditionMeansArray) secondfunction(UnFilteredDuringExSummaryOfMeansArray) return def secondfunction(UnFilteredDuringExSummaryOfMeansArray): RRDuringArray = p.array(UnFilteredDuringExSummaryOfMeansArray,dtype=p.float64)[1:,3] return firstfunction() Throws this error message: File "mypath\mypythonscript.py", line 3484, in secondfunction RRDuringArray = p.array(UnFilteredDuringExSummaryOfMeansArray,dtype=p.float64)[1:,3] ValueError: setting an array element with a sequence. However, this code works: import numpy as p a=range(24) b = p.reshape(a,(6,4)) c=p.array(b,dtype=p.float64)[:,2] I re-arranged the code a bit to put it into a cogent posting, but it should more or less have the same result. Can anyone show me what to do to fix the problem in the broken code above so that it stops throwing an error message?

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• MATLAB: How do I get 3D coordiantes from a user-click?

  - by Tim

  I'm using Matlab to create a small chess game for one of my courses this semester. The thing I'm having trouble with is having the user be able to select one of the chess pieces. To simplify things, I'm making it so that the user selects a piece by clicking on the square that the chess piece resides on rather than clicking the piece itself (which I assume would be much more difficult). I know how to get the x and y coordinates of the view-port, but how do I transform these coordinates into 3-space coordinates? I know that there are multiple x,y,z coordinates associated with each view-port coordinate, but I'm only interested in the x,y,z coordinate where z = 0 (since the board itself is in the x,y plane that intersects the z axis where z = 0). Thanks!

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• divs with z-index & position class

  - by Sotos

  hello, i need your help with div positioning into a page. i have the below divs: - the header with z-index 10, position absolute, top 0, height 250px, width 100% - wrapper with margin 0 auto, width 990 and inside - the menu with z-index 8 - content to the right of the menu with z-index 9 so that i could scroll it below the header. the problem is that i want the menu to have fixed position and this is not possible cause it is not working for the x-axis as it gets outside wrapper. Any ideas? thanks Sot

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• Make a loop that draws lines in processing

  - by theolc

  I have this piece of code, and i am wondering how to make a loop that will draw these lines... Every 50 pixels on the x-axis... I am curious as to how this can be done and would like to use a loop rather than manually drawing each line! The following is the code for the lines... Please any help would be much appreciated! //set sidewalk fill(255,255,255); rect(0,490,500,10); line(50,490,50,500); line(100,490,100,500); line(150,490,150,500); line(200,490,200,500); line(250,490,250,500); line(300,490,300,500); line(350,490,350,500); line(400,490,400,500); line(450,490,450,500);

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• Christmas advent calendar

  - by cf_PhillipSenn

  I have a vision of an advent calendar, where there are pictures of real windows with shudders, and when the user clicks on a picture, the shudders open to reveal what's behind them. How can I do this? I suppose I could use the primitive slideDown method in jQuery. But is there a slideLeft and slideRight? Or an openDoor, where each shudder rotates on an axis? This would be one div that has a transition of opening to both the left and right at the same time.

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• how to visualize (value, count) dataset with thousands data points

  - by user510040

  I have a file with 2 numeric columns: value and count. File may have 5000 rows. I do plot(value, count) to find the shape of distribution. But because there are too many data points the picture is not very clear. Do you know better visualization approach? Probably histograms or barplot with grouping close values on x axis will be the better way to look on data? I cannot figure out the syntax of using histogram or barplot for my case.

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• C# 5 Async, Part 2: Asynchrony Today

  - by Reed

  The .NET Framework has always supported asynchronous operations.  However, different mechanisms for supporting exist throughout the framework.  While there are at least three separate asynchronous patterns used through the framework, only the latest is directly usable with the new Visual Studio Async CTP.  Before delving into details on the new features, I will talk about existing asynchronous code, and demonstrate how to adapt it for use with the new pattern. The first asynchronous pattern used in the .NET framework was the Asynchronous Programming Model (APM).  This pattern was based around callbacks.  A method is used to start the operation.  It typically is named as BeginSomeOperation.  This method is passed a callback defined as an AsyncCallback, and returns an object that implements IAsyncResult.  Later, the IAsyncResult is used in a call to a method named EndSomeOperation, which blocks until completion and returns the value normally directly returned from the synchronous version of the operation.  Often, the EndSomeOperation call would be called from the callback function passed, which allows you to write code that never blocks. While this pattern works perfectly to prevent blocking, it can make quite confusing code, and be difficult to implement.  For example, the sample code provided for FileStream’s BeginRead/EndRead methods is not simple to understand.  In addition, implementing your own asynchronous methods requires creating an entire class just to implement the IAsyncResult. Given the complexity of the APM, other options have been introduced in later versions of the framework.  The next major pattern introduced was the Event-based Asynchronous Pattern (EAP).  This provides a simpler pattern for asynchronous operations.  It works by providing a method typically named SomeOperationAsync, which signals its completion via an event typically named SomeOperationCompleted. The EAP provides a simpler model for asynchronous programming.  It is much easier to understand and use, and far simpler to implement.  Instead of requiring a custom class and callbacks, the standard event mechanism in C# is used directly.  For example, the WebClient class uses this extensively.  A method is used, such as DownloadDataAsync, and the results are returned via the DownloadDataCompleted event. While the EAP is far simpler to understand and use than the APM, it is still not ideal.  By separating your code into method calls and event handlers, the logic of your program gets more complex.  It also typically loses the ability to block until the result is received, which is often useful.  Blocking often requires writing the code to block by hand, which is error prone and adds complexity. As a result, .NET 4 introduced a third major pattern for asynchronous programming.  The Task<T> class introduced a new, simpler concept for asynchrony.  Task and Task<T> effectively represent an operation that will complete at some point in the future.  This is a perfect model for thinking about asynchronous code, and is the preferred model for all new code going forward.  Task and Task<T> provide all of the advantages of both the APM and the EAP models – you have the ability to block on results (via Task.Wait() or Task<T>.Result), and you can stay completely asynchronous via the use of Task Continuations.  In addition, the Task class provides a new model for task composition and error and cancelation handling.  This is a far superior option to the previous asynchronous patterns. The Visual Studio Async CTP extends the Task based asynchronous model, allowing it to be used in a much simpler manner.  However, it requires the use of Task and Task<T> for all operations.

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• SQL SERVER – Puzzle #1 – Querying Pattern Ranges and Wild Cards

  - by Pinal Dave

  Note: Read at the end of the blog post how you can get five Joes 2 Pros Book #1 and a surprise gift. I have been blogging for almost 7 years and every other day I receive questions about Querying Pattern Ranges. The most common way to solve the problem is to use Wild Cards. However, not everyone knows how to use wild card properly. SQL Queries 2012 Joes 2 Pros Volume 1 – The SQL Queries 2012 Hands-On Tutorial for Beginners Book On Amazon | Book On Flipkart Learn SQL Server get all the five parts combo kit Kit on Amazon | Kit on Flipkart Many people know wildcards are great for finding patterns in character data. There are also some special sequences with wildcards that can give you even more power. This series from SQL Queries 2012 Joes 2 Pros® Volume 1 will show you some of these cool tricks. All supporting files are available with a free download from the www.Joes2Pros.com web site. This example is from the SQL 2012 series Volume 1 in the file SQLQueries2012Vol1Chapter2.2Setup.sql. If you need help setting up then look in the “Free Videos” section on Joes2Pros under “Getting Started” called “How to install your labs” Querying Pattern Ranges The % wildcard character represents any number of characters of any length. Let’s find all first names that end in the letter ‘A’. By using the percentage ‘%’ sign with the letter ‘A’, we achieve this goal using the code sample below: SELECT * FROM Employee WHERE FirstName LIKE '%A' To find all FirstName values beginning with the letters ‘A’ or ‘B’ we can use two predicates in our WHERE clause, by separating them with the OR statement. Finding names beginning with an ‘A’ or ‘B’ is easy and this works fine until we want a larger range of letters as in the example below for ‘A’ thru ‘K’: SELECT * FROM Employee WHERE FirstName LIKE 'A%' OR FirstName LIKE 'B%' OR FirstName LIKE 'C%' OR FirstName LIKE 'D%' OR FirstName LIKE 'E%' OR FirstName LIKE 'F%' OR FirstName LIKE 'G%' OR FirstName LIKE 'H%' OR FirstName LIKE 'I%' OR FirstName LIKE 'J%' OR FirstName LIKE 'K%' The previous query does find FirstName values beginning with the letters ‘A’ thru ‘K’. However, when a query requires a large range of letters, the LIKE operator has an even better option. Since the first letter of the FirstName field can be ‘A’, ‘B’, ‘C’, ‘D’, ‘E’, ‘F’, ‘G’, ‘H’, ‘I’, ‘J’ or ‘K’, simply list all these choices inside a set of square brackets followed by the ‘%’ wildcard, as in the example below: SELECT * FROM Employee WHERE FirstName LIKE '[ABCDEFGHIJK]%' A more elegant example of this technique recognizes that all these letters are in a continuous range, so we really only need to list the first and last letter of the range inside the square brackets, followed by the ‘%’ wildcard allowing for any number of characters after the first letter in the range. Note: A predicate that uses a range will not work with the ‘=’ operator (equals sign). It will neither raise an error, nor produce a result set. --Bad query (will not error or return any records) SELECT * FROM Employee WHERE FirstName = '[A-K]%' Question: You want to find all first names that start with the letters A-M in your Customer table and end with the letter Z. Which SQL code would you use? a. SELECT * FROM Customer WHERE FirstName LIKE 'm%z' b. SELECT * FROM Customer WHERE FirstName LIKE 'a-m%z' c. SELECT * FROM Customer WHERE FirstName LIKE 'a-m%z' d. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]%z' e. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]z%' f. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]%z' g. SELECT * FROM Customer WHERE FirstName LIKE '[a-m]z%' Contest Leave a valid answer before June 18, 2013 in the comment section. 5 winners will be selected from all the valid answers and will receive Joes 2 Pros Book #1. 1 Lucky person will get a surprise gift from Joes 2 Pros. The contest is open for all the countries where Amazon ships the book (USA, UK, Canada, India and many others). Special Note: Read all the options before you provide valid answer as there is a small trick hidden in answers. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Joes 2 Pros, PostADay, SQL, SQL Authority, SQL Puzzle, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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• When to use Aspect Oriented Architecture (AOA/AOD)

  When is it appropriate to use aspect oriented architecture? I think the only honest answer to this question is that it depends on the context for which the question is being asked. There really are no hard and fast rules regarding the selection of an architectural model(s) for a project because each model provides good and bad benefits. Every system is built with a unique requirements and constraints. This context will dictate when to use one type of architecture over another or in conjunction with others. To me aspect oriented architecture models should be a sub-phase in the architectural modeling and design process especially when creating enterprise level models. Personally, I like to use this approach to create a base architectural model that is defined by non-functional requirements and system quality attributes.   This general model can then be used as a starting point for additional models because it is targets all of the business key quality attributes required by the system.Aspect oriented architecture is a method for modeling non-functional requirements and quality attributes of a system known as aspects. These models do not deal directly with specific functionality. They do categorize functionality of the system. This approach allows a system to be created with a strong emphasis on separating system concerns into individual components. These cross cutting components enables a systems to create with compartmentalization in regards to non-functional requirements or quality attributes.  This allows for the reduction in code because an each component maintains an aspect of a system that can be called by other aspects. This approach also allows for a much cleaner and smaller code base during the implementation and support of a system. Additionally, enabling developers to develop systems based on aspect-oriented design projects will be completed faster and will be more reliable because existing components can be shared across a system; thus, the time needed to create and test the functionality is reduced.   Example of an effective use of Aspect Oriented ArchitectureIn my experiences, aspect oriented architecture can be very effective with large or more complex systems. Typically, these types of systems have a large number of concerns so the act of defining them is very beneficial for reducing the system’s complexity because components can be developed to address each concern while exposing functionality to the other system components. The benefits to using the aspect oriented approach as the starting point for a system is that it promotes communication between IT and the business due to the fact that the aspect oriented models are quality attributes focused so not much technical understanding is needed to understand the model.An example of this can be in developing a new intranet website. Common Intranet Concerns: Error Handling Security Logging Notifications Database connectivity Example of a not as effective use of Aspect Oriented ArchitectureAgain in my experiences, aspect oriented architecture is not as effective with small or less complex systems in comparison.  There is no need to model concerns for a system that has a limited amount of them because the added overhead would not be justified for the actual benefits of creating the aspect oriented architecture model.  Furthermore, these types of projects typically have a reduced time schedule and a limited budget.  The creation of the Aspect oriented models would increase the overhead of a project and thus increase the time needed to implement the system. An example of this is seen by creating a small application to poll a network share for new files and then FTP them to a new location.  The two primary concerns for this project is to monitor a network drive and FTP files to a new location.  There is no need to create an aspect model for this system because there will never be a need to share functionality amongst either of these concerns.  To add to my point, this system is so small that it could be created with just a few classes so the added layer of componentizing the concerns would be complete overkill for this situation. References:Brichau, Johan; D'Hondt, Theo. (2006) Aspect-Oriented Software Development (AOSD) - An Introduction. Retreived from: http://www.info.ucl.ac.be/~jbrichau/courses/introductionToAOSD.pdf

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• Node.js Lockstep Multiplayer Architecture

  - by Wakaka

  Background I'm using the lockstep model for a multiplayer Node.js/Socket.IO game in a client-server architecture. User input (mouse or keypress) is parsed into commands like 'attack' and 'move' on the client, which are sent to the server and scheduled to be executed on a certain tick. This is in contrast to sending state data to clients, which I don't wish to use due to bandwidth issues. Each tick, the server will send the list of commands on that tick (possibly empty) to each client. The server and all clients will then process the commands and simulate that tick in exactly the same way. With Node.js this is actually quite simple due to possibility of code sharing between server and client. I'll just put the deterministic simulator in the /shared folder which can be run by both server and client. The server simulation is required so that there is an authoritative version of the simulation which clients cannot alter. Problem Now, the game has many entity classes, like Unit, Item, Tree etc. Entities are created in the simulator. However, for each class, it has some methods that are shared and some that are client-specific. For instance, the Unit class has addHp method which is shared. It also has methods like getSprite (gets the image of the entity), isVisible (checks if unit can be seen by the client), onDeathInClient (does a bunch of stuff when it dies only on the client like adding announcements) and isMyUnit (quick function to check if the client owns the unit). Up till now, I have been piling all the client functions into the shared Unit class, and adding a this.game.isServer() check when necessary. For instance, when the unit dies, it will call if (!this.game.isServer()) { this.onDeathInClient(); }. This approach has worked pretty fine so far, in terms of functionality. But as the codebase grew bigger, this style of coding seems a little strange. Firstly, the client code is clearly not shared, and yet is placed under the /shared folder. Secondly, client-specific variables for each entity are also instantiated on the server entity (like unit.sprite) and can run into problems when the server cannot instantiate the variable (it doesn't have Image class like on browsers). So my question is, is there a better way to organize the client code, or is this a common way of doing things for lockstep multiplayer games? I can think of a possible workaround, but it does have its own problems. Possible workaround (with problems) I could use Javascript mixins that are only added when in a browser. Thus, in the /shared/unit.js file in the /shared folder, I would have this code at the end: if (typeof exports !== 'undefined') module.exports = Unit; else mixin(Unit, LocalUnit); Then I would have /client/localunit.js store an object LocalUnit of client-side methods for Unit. Now, I already have a publish-subscribe system in place for events in the simulator. To remove the this.game.isServer() checks, I could publish entity-specific events whenever I want the client to do something. For instance, I would do this.publish('Death') in /shared/unit.js and do this.subscribe('Death', this.onDeathInClient) in /client/localunit.js. But this would make the simulator's event listeners list on the server and the client different. Now if I want to clear all subscribed events only from the shared simulator, I can't. Of course, it is possible to create two event subscription systems - one client-specific and one shared - but now the publish() method would have to do if (!this.game.isServer()) { this.publishOnClient(event); }. All in all, the workaround off the top of my head seems pretty complicated for something as simple as separating the client and shared code. Thus, I wonder if there is an established and simpler method for better code organization, hopefully specific to Node.js games.

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• Changes in Language Punctuation [closed]

  - by Wes Miller

  More social curiosity than actual programming question... (I got shot for posting this on Stack Overflow. They sent me here. At least i hope here is where they meant.) Based on the few responses I got before the content police ran me off Stack Overflow, I should note that I am legally blind and neatness and consistency in programming are my best friends. A thousand years ago when I took my first programming class (Fortran 66) and a mere 500 years ago when I tokk my first C and C++ classes, there were some pretty standard punctuation practices across languages. I saw them in Basic (shudder), PL/1, PL/AS, Rexx even Pascal. Ok, APL2 is not part of this discussion. Each language has its own peculiar punctuation. Pascal's periods, Fortran's comma separated do loops, almost everybody else's semicolons. As I learned it, each language also has KEYWORDS (if, for, do, while, until, etc.) which are set off by whitespace (or the left margin) if, etc. Each language has function, subroutines of whatever they're called. Some built-in some user coded. They were set off by function_name( parameters );. As in sqrt( x ) or rand( y ); Lately, there seems to be a new set of punctuation rules. Especially in c++ where initializers get glued onto the end of variable declarations int x(0); or auto_ptr p(new gizmo); This usually, briefly fools me into thinking someone is declaring a function prototype or using a function as a integer. Then "if" and 'for' seems to have grown parens; if(true) for(;;), etc. Since when did keywords become functions. I realize some people think they ARE functions with iterators as parameters. But if "for" is a function, where did the arg separating commas go? And finally, functions seem to have shed their parens; sqrt (2) select (...) I know, I koow, loosening whitespace rules is good. Keep reading. Question: when did the old ways disappear and this new way come into vogue? Does anyone besides me find it irritating to read and that the information that the placement of punctuation used to convey is gone? I know full well that K&R put the { at the end of the "if" or "for" to save a byte here and there. Can't use that excuse here. Space as an excuse for loss of readability died as HDD space soared past 100 MiB. Your thoughts are solicited. If there is a good reason to do this, I'll gladly learn it and maybe in another 50 years I'll get used to it. Of course it's good that compilers recognize these (IMHO) typos and keep right on going, but just because you CAN code it that way doesn't mean you HAVE to, right?

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• Need WIF Training?

  - by Your DisplayName here!

  I spend numerous hours every month answering questions about WIF and identity in general. This made me realize that this is still quite a complicated topic once you go beyond the standard fedutil stuff. My good friend Brock and I put together a two day training course about WIF that covers everything we think is important. The course includes extensive lab material where you take standard application and apply all kinds of claims and federation techniques and technologies like WS-Federation, WS-Trust, session management, delegation, home realm discovery, multiple identity providers, Access Control Service, REST, SWT and OAuth. The lab also includes the latest version of the thinktecture identityserver and you will learn how to use and customize it. If you are looking for an open enrollment style of training, have a look here. Or contact me directly! The course outline looks as follows: Day 1 Intro to Claims-based Identity & the Windows Identity Foundation WIF introduces important concepts like conversion of security tokens and credentials to claims, claims transformation and claims-based authorization. In this module you will learn the basics of the WIF programming model and how WIF integrates into existing .NET code. Externalizing Authentication for Web Applications WIF includes support for the WS-Federation protocol. This protocol allows separating business and authentication logic into separate (distributed) applications. The authentication part is called identity provider or in more general terms - a security token service. This module looks at this scenario both from an application and identity provider point of view and walks you through the necessary concepts to centralize application login logic both using a standard product like Active Directory Federation Services as well as a custom token service using WIF’s API support. Externalizing Authentication for SOAP Services One big benefit of WIF is that it unifies the security programming model for ASP.NET and WCF. In the spirit of the preceding modules, we will have a look at how WIF integrates into the (SOAP) web service world. You will learn how to separate authentication into a separate service using the WS-Trust protocol and how WIF can simplify the WCF security model and extensibility API. Day 2 Advanced Topics:  Security Token Service Architecture, Delegation and Federation The preceding modules covered the 80/20 cases of WIF in combination with ASP.NET and WCF. In many scenarios this is just the tip of the iceberg. Especially when two business partners decide to federate, you usually have to deal with multiple token services and their implications in application design. Identity delegation is a feature that allows transporting the client identity over a chain of service invocations to make authorization decisions over multiple hops. In addition you will learn about the principal architecture of a STS, how to customize the one that comes with this training course, as well as how to build your own. Outsourcing Authentication:  Windows Azure & the Azure AppFabric Access Control Service Microsoft provides a multi-tenant security token service as part of the Azure platform cloud offering. This is an interesting product because it allows to outsource vital infrastructure services to a managed environment that guarantees uptime and scalability. Another advantage of the Access Control Service is, that it allows easy integration of both the “enterprise” protocols like WS-* as well as “web identities” like LiveID, Google or Facebook into your applications. ACS acts as a protocol bridge in this case where the application developer doesn’t need to implement all these protocols, but simply uses a service to make it happen. Claims & Federation for the Web and Mobile World Also the web & mobile world moves to a token and claims-based model. While the mechanics are almost identical, other protocols and token types are used to achieve better HTTP (REST) and JavaScript integration for in-browser applications and small footprint devices. Also patterns like how to allow third party applications to work with your data without having to disclose your credentials are important concepts in these application types. The nice thing about WIF and its powerful base APIs and abstractions is that it can shield application logic from these details while you can focus on implementing the actual application. HTH

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• Social Search: Looking for Love

  - by Mike Stiles

  For marketers and enterprise executives who have placed a higher priority on and allocated bigger budgets to search over social, it might be time to notice yet another shift that’s well underway. Social is search. Search marketing was always more of an internal slam-dunk than other digital initiatives. Even a C-suite that understood little about the new technology world knew it’s a good thing when people are able to find you. Google was the new Yellow Pages. Only with Google, you could get your listing first without naming yourself “AAAA Plumbing.” There were wizards out there who could give your business prominence in front of people who were specifically looking for what you offered. Other search giants like Bing also came along to offer such ideal matchmaking possibilities. But what if the consumer isn’t using a search engine to find what they’re looking for? And what if the search engines started altering their algorithms so that search placement manipulation was more difficult? Both of those things have started to happen. Experian Hitwise’s numbers show that visits to the major search engines in the UK dropped 100 million through August. Search engines are far from dead, or even challenged. But more and more, the public is discovering the sites and brands they need through advice they get via social, not search. You’ll find the worlds of social and search increasingly co-mingling as well. Search behemoths Google and Bing are including Facebook and Google+ into their engines. Meanwhile, Facebook and Twitter have done some integration of global web search into their platforms. So what makes social such a worthwhile search entity for brands? First and foremost, the consumer has demonstrated a behavior of acting on recommendations from social connections. A cry in the wilderness like, “Anybody know any good catering companies?” will usually yield a link (and an endorsement) from a friend such as “Yeah, check out Just-Cheese-Balls Catering.” There’s no such human-driven force/influence behind the big search engines. Facebook’s Mark Zuckerberg and others call it “Friend Mining.” It is, in essence, searching for answers from friends’ experiences as opposed to faceless code. And Facebook has all of those friends’ experiences already stored as data. eMarketer says search in an $18 billion business, and investors are really into it. So no shock Facebook’s ready to leverage their social graph into relevant search. What do you do about all this as a brand? For one thing, it’s going to lead to some interesting paid marketing opportunities around the corner, including Sponsored Stories bought against certain queries, inserting deals into search results, capitalizing on social search results on mobile, etc. Apart from that, it might be time to stop mentally separating social and search in your strategic planning and budgeting. Courting your fans on social will cumulatively add up to more valuable, personally endorsed recommendations for your company when a consumer conducts a search on social. Fail to foster those relationships, fail to engage, fail to provide knock-em-dead customer service, fail to wow them with your actual products and services…and you’ll wind up with the visibility you deserve in social search results.

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• How do you formulate the Domain Model in Domain Driven Design properly (Bounded Contexts, Domains)?

  - by lko

  Say you have a few applications which deal with a few different Core Domains. The examples are made up and it's hard to put a real example with meaningful data together (concisely). In Domain Driven Design (DDD) when you start looking at Bounded Contexts and Domains/Sub Domains, it says that a Bounded Context is a "phase" in a lifecycle. An example of Context here would be within an ecommerce system. Although you could model this as a single system, it would also warrant splitting into separate Contexts. Each of these areas within the application have their own Ubiquitous Language, their own Model, and a way to talk to other Bounded Contexts to obtain the information they need. The Core, Sub, and Generic Domains are the area of expertise and can be numerous in complex applications. Say there is a long process dealing with an Entity for example a Book in a core domain. Now looking at the Bounded Contexts there can be a number of phases in the books life-cycle. Say outline, creation, correction, publish, sale phases. Now imagine a second core domain, perhaps a store domain. The publisher has its own branch of stores to sell books. The store can have a number of Bounded Contexts (life-cycle phases) for example a "Stock" or "Inventory" context. In the first domain there is probably a Book database table with basically just an ID to track the different book Entities in the different life-cycles. Now suppose you have 10+ supporting domains e.g. Users, Catalogs, Inventory, .. (hard to think of relevant examples). For example a DomainModel for the Book Outline phase, the Creation phase, Correction phase, Publish phase, Sale phase. Then for the Store core domain it probably has a number of life-cycle phases. public class BookId : Entity { public long Id { get; set; } } In the creation phase (Bounded Context) the book could be a simple class. public class Book : BookId { public string Title { get; set; } public List<string> Chapters { get; set; } //... } Whereas in the publish phase (Bounded Context) it would have all the text, release date etc. public class Book : BookId { public DateTime ReleaseDate { get; set; } //... } The immediate benefit I can see in separating by "life-cycle phase" is that it's a great way to separate business logic so there aren't mammoth all-encompassing Entities nor Domain Services. A problem I have is figuring out how to concretely define the rules to the physical layout of the Domain Model. A. Does the Domain Model get "modeled" so there are as many bounded contexts (separate projects etc.) as there are life-cycle phases across the core domains in a complex application? Edit: Answer to A. Yes, according to the answer by Alexey Zimarev there should be an entire "Domain" for each bounded context. B. Is the Domain Model typically arranged by Bounded Contexts (or Domains, or both)? Edit: Answer to B. Each Bounded Context should have its own complete "Domain" (Service/Entities/VO's/Repositories) C. Does it mean there can easily be 10's of "segregated" Domain Models and multiple projects can use it (the Entities/Value Objects)? Edit: Answer to C. There is a complete "Domain" for each Bounded Context and the Domain Model (Entity/VO layer/project) isn't "used" by the other Bounded Contexts directly, only via chosen paths (i.e. via Domain Events). The part that I am trying to figure out is how the Domain Model is actually implemented once you start to figure out your Bounded Contexts and Core/Sub Domains, particularly in complex applications. The goal is to establish the definitions which can help to separate Entities between the Bounded Contexts and Domains.

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• Would this be a good web application architecture?

  - by Gustav Bertram

  My problem Our MVC based framework does not allow us to cache only part of our output. Ideally we want to cahce static and semi-static bits, and run dynamic bits. In addition, we need to consider data caching that reacts to database changes. My idea The concept I came up with was to represent a page as a tree of XML fragment objects. (I say XML, but I mean XHTML). Some of the fragments are dynamic, and can pull their data directly from models or other sources, but most of the fragments are static scaffolding. If a subtree of fragments is completely static, then I imagine that they could unfold into pure XML that would then be cached as the text representation of their parent element. This process would ideally continue until we are left with a root element that contains all of the static XML, and has a couple of dynamic XML fragments that are resolved and attached to the relevant nodes of the XML tree just before the page is displayed. In addition to separating content into dynamic and static fragments, some fragments could be dynamic and cached. A simple expiry time which propagates up through the XML fragment tree would indicate that a specific fragment should periodically be refreshed. A newspaper section or front page does not need to be updated each second. Minutes or sometimes even longer is sufficient. Other fragments would be dynamic and uncached. Typically too many articles are viewed for them to be cached - the cache would overflow. Some individual articles may be cached if they are extremely popular. Functional notes The folding mechanism could be to be smart enough to judge when it would be more profitable to fold a dynamic cached fragment and propagate the expiry date to the parent fragment, or to keep it separate and simple attach to the XML tree when resolving the page. If some dynamic cached fragments are associated to database objects through mechanisms like a globally unique content id, then changes to the database could trigger changes to the output cache. If fragments store the identifiers of parent fragments, then they could trigger a refolding process that would then include the updated data. A set of pure XML with an ordered array of fragment objects (that each store the identifying information of the node to which they should be attached), can be resolved in a fairly simple way by walking the XML tree, and merging the data from the fragments. Because it is not necessary to parse and construct the entire tree in memory before attaching nodes, processing should be fairly fast. The identifiers of each fragment would be a combination of relevant identity data and the type of fragment object. Cached parent fragments would contain references to these identifiers, in order to then either pull them from the fragment cache, or to run their code. The controller's responsibility is reduced to making changes to the database, and telling the root XML fragment object to render itself. The Question My question has two parts: Is this a good design? Are there any obvious flaws I'm missing? Has somebody else thought of this before? References? Is there an existing alternative that I should consider? A cool templating engine maybe?

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• How to make a stack stable? Need help for an explicit resting contact scheme (2-dimensional)

  - by Register Sole

  Previously, I struggle with the sequential impulse-based method I developed. Thanks to jedediah referring me to this paper, I managed to rebuild the codes and implement the simultaneous impulse based method with Projected-Gauss-Seidel (PGS) iterative solver as described by Erin Catto (mentioned in the reference of the paper as [Catt05]). So here's how it currently is: The simulation handles 2-dimensional rotating convex polygons. Detection is using separating-axis test, with a SKIN, meaning closest points between two polygons is detected and determined if their distance is less than SKIN. To resolve collision, simultaneous impulse-based method is used. It is solved using iterative solver (PGS-solver) as in Erin Catto's paper. Error-correction is implemented using Baumgarte's stabilization (you can refer to either paper for this) using J V = beta/dt*overlap, J is the Jacobian for the constraints, V the matrix containing the velocities of the bodies, beta an error-correction parameter that is better be < 1, dt the time-step taken by the engine, and overlap, the overlap between the bodies (true overlap, so SKIN is ignored). However, it is still less stable than I expected :s I tried to stack hexagons (or squares, doesn't really matter), and even with only 4 to 5 of them, they would swing! Also note that I am not looking for a sleeping scheme. But I would settle if you have any explicit scheme to handle resting contacts. That said, I would be more than happy if you have a way of treating it generally (as continuous collision, instead of explicitly as a special state). Ideas I have tried: Using simultaneous position based error correction as described in the paper in section 5.3.2, turned out to be worse than the current scheme. If you want to know the parameters I used: Hexagons, side 50 (pixels) gravity 2400 (pixels/sec^2) time-step 1/60 (sec) beta 0.1 restitution 0 to 0.2 coeff. of friction 0.2 PGS iteration 10 initial separation 10 (pixels) mass 1 (unit is irrelevant for now, i modified velocity directly<-impulse method) inertia 1/1000 Thanks in advance! I really appreciate any help from you guys!! :) EDIT In response to Cholesky's comment about warm starting the solver and Baumgarte: Oh right, I forgot to mention! I do save the contact history and the impulse determined in this time step to be used as initial guess in the next time step. As for the Baumgarte, here's what actually happens in the code. Collision is detected when the bodies' closest distance is less than SKIN, meaning they are actually still separated. If at this moment, I used the PGS solver without Baumgarte, restitution of 0 alone would be able to stop the bodies, separated by a distance of ~SKIN, in mid-air! So this isn't right, I want to have the bodies touching each other. So I turn on the Baumgarte, where its role is actually to pull the bodies together! Weird I know, a scheme intended to push the body apart becomes useful for the reverse. Also, I found that if I increase the number of iteration to 100, stacks become much more stable, though the program becomes so slow. UPDATE Since the stack swings left and right, could it be something is wrong with my friction model? Current friction constraint: relative_tangential_velocity = 0

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• iPhone: how to use performSelector:onThread:withObject:waitUntilDone: method?

  - by Michael Kessler

  Hi all, I am trying to use a separate thread for working with some API. The problem is that I am not able to use performSelector:onThread:withObject:waitUntilDone: method with a thread that I' instantiated for this. My code: @interface MyObject : NSObject { NSThread *_myThread; } @property(nonatomic, retain) NSThread *myThread; @end @implementation MyObject @synthesize myThread = _myThread; - (NSThread *)myThread { if (_myThread == nil) { NSThread *myThreadTemp = [[NSThread alloc] init]; [myThreadTemp start]; self. myThread = myThreadTemp; [myThreadTemp release]; } return _myThread; } - (id)init { if (self = [super init]) { [self performSelector:@selector(privateInit:) onThread:[self myThread] withObject:nil waitUntilDone:NO]; } return self; } - (void)privateInit:(id)object { NSLog(@"MyObject - privateInit start"); } - (void)dealloc { [_myThread release]; _myThread = nil; [super dealloc]; } @end "MyObject - privateInit start" is never printed. What am I missing? I tried to instantiate the thread with target and selector, tried to wait for method execution completion (waitUntilDone:YES). Nothing helps. UPDATE: I don't need this multithreading for separating costly operations to another thread. In this case I could use the performSelectorInBackground as mentioned in few answers. The main reason for this separate thread is the need to perform all the actions in the API (TTS by Loquendo) from one single thread. Meaning that I have to create an instance of the TTS object and call methods on that object from the same thread all the time.

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• 2-column; multi-accordion pane

  - by Josh

  Alright, I'm having some issues and I believe it's a CSS one. Here is what I'm working on currently: http://www.notedls.com/demo/ Focusing on the News accordion menu. The idea here is to have a small image (50x50 with padding) and then a huge headline next to it. When the user clicks the headline, it expands to the article. If the user wants to read comments or make a comment themselves they can then click the View Comments to expand it even further. The issue I'm having (if it isn't clear) is the spacing with the image and the text. I could simply just increase the height of the ui.accordion-acc or -left to make everything fit, but that doesn't solve the issue. If you notice when you click on the first expansion of Headline 1, it will wrap View Comments underneath the image. This is something I don't want, I've tried separating these elements into additional divs and even floating, but its just not working. Essentially, I want blank space infinitely underneath the image for however long the article+comments may take the field.

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• Best Diff Tool?

  - by ila

  For all my present Diff / Merge needs I'm using Beyond Compare; when I decided to buy a license for it I tried other similar tools, both payware and freeware. Now BC is at version 3, and I think it's a great tool... but what are your experience in this field? Do you think there is something better? And what are the feature you like best on your favorite Diff tool? EDIT I'm recollecting here a list of the tools mentioned in the answers below, in order of preferences (more or less), separating pay- from free- ware and indicating supported operating system. Hope this helps. PAYWARE Beyond Compare (win + linux) - http://www.scootersoftware.com/ Araxis Merge (win + osX) - http://www.araxis.com/merge/index.html ExamDiff Pro (win) - http://www.prestosoft.com/edp_examdiffpro.asp ECMerge (win, osX, linux) - http://www.elliecomputing.com/Home/default.asp MergePlant (win) - http://www.mikado-ltd.com/ Changes (OSX) http://www.changesapp.com Deltopia DeltaWalker (win, osx, linux) http://www.deltopia.com/ FREEWARE FileMerge (OSX) - http://en.wikipedia.org/wiki/Apple_Developer_Tools#FileMerge Tortoise SVN (win) - http://tortoisesvn.net/ WinMerge (win) - http://winmerge.org/ ExamDiff (win) - http://www.prestosoft.com/ps.asp?page=edp_examdiff Diff Merge from SourceGear - http://www.sourcegear.com/diffmerge/index.html Perforce Merge (win + linux + OSX) - http://www.perforce.com/perforce/products/merge.html meld (linux) - sudo apt-get install meld http://meld.sourceforge.net/ Vimdiff - vim distribution KDiff3 - http://kdiff3.sf.net/ ediff - EMacs distribution Tiny Hexer Kompare (KDE, linux) - http://www.caffeinated.me.uk/kompare/ tkdiff (win, linux, osX) - http://tkdiff.sourceforge.net

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• Structuring projects & dependencies of large winforms applications in C#

  - by Benjol

  UPDATE: This is one of my most-visited questions, and yet I still haven't really found a satisfactory solution for my project. One idea I read in an answer to another question is to create a tool which can build solutions 'on the fly' for projects that you pick from a list. I have yet to try that though. How do you structure a very large application? Multiple smallish projects/assemblies in one big solution? A few big projects? One solution per project? And how do you manage dependencies in the case where you don't have one solution. Note: I'm looking for advice based on experience, not answers you found on Google (I can do that myself). I'm currently working on an application which has upward of 80 dlls, each in its own solution. Managing the dependencies is almost a full time job. There is a custom in-house 'source control' with added functionality for copying dependency dlls all over the place. Seems like a sub-optimum solution to me, but is there a better way? Working on a solution with 80 projects would be pretty rough in practice, I fear. (Context: winforms, not web) EDIT: (If you think this is a different question, leave me a comment) It seems to me that there are interdependencies between: Project/Solution structure for an application Folder/File structure Branch structure for source control (if you use branching) But I have great difficulty separating these out to consider them individually, if that is even possible. I have asked another related question here.

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• Separation of multipage tiff with compression "CCITT T.6" very slow

  - by Alex

  I need to separate multiframe tiff files, and use the following method: public static Image[] GetFrames(Image sourceImage) { Guid objGuid = sourceImage.FrameDimensionsList[0]; FrameDimension objDimension = new FrameDimension(objGuid); int frameCount = sourceImage.GetFrameCount(objDimension); Image[] images = new Image[frameCount]; for (int i = 0; i < frameCount; i++) { MemoryStream ms = new MemoryStream(); sourceImage.SelectActiveFrame(objDimension, i); sourceImage.Save(ms, ImageFormat.Tiff); images[i] = Image.FromStream(ms); } return images; } It works fine, but if the source image was encoded using the CCITT T.6 compression, separating a 20-frame-file takes up to 15 seconds on my 2,5ghz CPU.(edit: One core is at 100% during the process) When saving the images afterward to a single file using standard compression (LZW), the separation time of the LZW-file is under 1 second. Saving with CCITT compression also takes very long. Is there a way to speed up the process?

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• Deploy multiple instances of an EAR (representing versions) to Glassfish

  - by Thorbjørn Ravn Andersen

  I basically want to be able to deploy multiple versions of the same EAR file to the same server (Glassfish instance?) , and have a unique path to each version separating them. From my reading on this it appears that multiple EARs deploy to the root of the web server namespace so that they can coexist if they do not have colliding context-root's of WAR's. In my case I'd rather have that instead of everything going under "/", I'd like to be able to brand a given EAR-file build to ALWAYS deploy under a given path like "/foo-20100319" or "/foo-CUSTOMER-20010101". This can easily be done with a single WAR file just by renaming it. I do not need or want them to disturb each other. It is my understanding that this remapping is outside the scope of the application.xml file, so I found that http://docs.sun.com/app/docs/doc/820-7693/beayr?a=view says that I can specify web-uri and context-root, but I am not certain that what I wish to do, can be specified with these in Glassfish. How should I approach this? I have full control over the build process. (I have found http://stackoverflow.com/questions/877390/deploying-multiple-java-web-apps-to-glassfish-in-one-go but I am not certain how to apply this to what I need).

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• What's are the best readings to start using WPF instead of WinForms?

  - by Ivan

  Keeping in mind what CannibalSmith once said - "All the answers are saying "WPF is different". That's a huge understatement. You not only have to learn lots of new stuff - you must forget everything you've learned from Forms. It's a completely new way of doing UI." .. and having many years of experience with visual Windows desktop applications development (VB6, Borland C++ Builder VCL, WinForms) (which is hard to forget), how do I quickly move to developing to say well-formed WPF applications with Visual Studio? I don't need boozy-woozy graphics to give my app look and feel of a Hollywood blockbuster or a million dollar pyjamas. I always loved tidiness of standard Windows common controls and UI design guidelines, end even more I enjoyed them under Vista Glass Aero Graphite sauce. I am perfectly satisfied with WinForms but I want to my applications to be built of the most efficient and up-to-date standard technologies and architectured according to the most efficient and flexible patterns of today and tomorrow, leveraging interface-based integration and functionality reuse and to take all advantages of modern hardware and APIs to maximize performance, usability, reliability, maintainability, extensibility, etc. I very much like the idea of separating view, logic and data, letting a view to take all advantages of the platform (may it run as a web browser applet on a thin client or as a desktop application on a PC with a latest GPU), letting logic be reused, parallelized and seamlessly evolve, storing data in a well structured format in a right place. But... while moving from VB6 to Borland C++ Builder was very easy (no books/tutorials needed to turn it on and start working) (assuming I already knew C++), moving from BCB to WinForms was the same seamless, it does not seem any obvious to me how to do with WPF. So how do I best convert myself from a WinForms developer into a right-way thinking and doing WPF developer?

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