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  • Nearest color algorithm using Hex Triplet

    - by Lijo
    Following page list colors with names http://en.wikipedia.org/wiki/List_of_colors. For example #5D8AA8 Hex Triplet is "Air Force Blue". This information will be stored in a databse table (tbl_Color (HexTriplet,ColorName)) in my system Suppose I created a color with #5D8AA7 Hex Triplet. I need to get the nearest color available in the tbl_Color table. The expected anaser is "#5D8AA8 - Air Force Blue". This is because #5D8AA8 is the nearest color for #5D8AA7. Do we have any algorithm for finding the nearest color? How to write it using C# / Java? REFERENCE http://stackoverflow.com/questions/5440051/algorithm-for-parsing-hex-into-color-family http://stackoverflow.com/questions/6130621/algorithm-for-finding-the-color-between-two-others-in-the-colorspace-of-painte Suggested Formula: Suggested by @user281377. Choose the color where the sum of those squared differences is minimal (Square(Red(source)-Red(target))) + (Square(Green(source)-Green(target))) +(Square(Blue(source)-Blue(target)))

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  • Making your ASP.NET/HTML Websites Indic aware &ndash; accepting Tamil, Telugu, Kannada, Hindi and ot

    - by Harish Ranganathan
    Its been a month since I wrote my last post.  Much of work has been happening around planning for Tech Ed India, the upcoming Virtual TechDays this week as well as our Developer content at the Great Indian Developer Summit 2010.  Its going to be one exciting period starting this week and I am glad I would be able to meet a lot of folks who have written to me personally that they would like to catch up at Tech Ed India. For now, I had a chance to meet the Microsoft India Development Centre team that worked on the Microsoft Indic Language Input Tool (erstwhile Akshara). The team updated me that they have also released the scripts  so that the Indic input feature can be encapsulated into your own websites.  For example, if you are having a web page where you collect user information, you can pretty much make your site indic aware i.e. accept inputs in Tamil, Telugu, Kannada, Hindi etc.,  All you would need to include would be a bunch of scripts onto your web pages and you are ready to make it, like I said, “indic aware” I have built a sample web page that accepts First Name, Last Name, Address and an additional field.  When it comes to accepting indic, sometimes, you may want to avoid the indic input in certain fields and accept it in English.  You can specify the MicrosoftILITWebAttach="false" attribute to the Text Boxes and Text Areas (TextMode=”Multiline” in ASP.NET) so that the particular field automatically switches over to English input.  Similarly, the moment you specify that the TextMode=”Password” to make it as a password field, it automatically ignores all indic recognition and shows the masked dots for the words entered. Note that, this is, when we are going for the Opt-out mode, where we are specifying that by default all the input controls would need indic awareness and we would specify for those controls where it is not required.  The other mode is Opt-in mode where you would need to add a different property to the script definition i.e. attachMode=”optin” .  When we do this, we need to explicitly add the MicrosoftILITWebAttach="true" attribute for every control where we need indic input. I have created a sample web page which accepts First Name, Last Name, Address and an additional input field to demonstrate the “Opt-out”.   You can copy paste this into any of your web pages to check it <form id="form1" runat="server">     <!-- Microsoft Indic Language Input Tool embed code --> <input type="hidden" id="MicrosoftILITWebEmbedInfo" attachMode="optout" value="" /> <script type="text/javascript" src="http://ilit.microsoft.com/bookmarklet/script/Tamil.js" defer="defer"></script>     <div>     <h2>         Welcome to the Registration Page     </h2>     <p>         First Name: <asp:TextBox runat="server" ID="txtFirstName" />         <br />         <br />         Last Name: <asp:TextBox runat="server" ID="txtLastName" />         <br />         <br />         Password:         <asp:TextBox runat="server" ID="txtPassword" TextMode="Password" />         <br />         <br />         Address: <asp:TextBox runat="server" ID="txtAddress" TextMode="MultiLine" Height="100" Width="200" />         <br />         <br />         English Text: <asp:TextBox ID="txtEnglishText" runat="server" MicrosoftILITWebAttach="false" />     </p>     <p>         <!-- Microsoft Indic Language Input Tool attribution image link --> <a style="text-decoration: none" href="http://go.microsoft.com/fwlink/?LinkID=184205&clcid=0x409"><img style="border: 0px" alt="Transliteration by Microsoft" src="http://ilit.microsoft.com/bookmarklet/images/attribution.png"></a>     </p>     </div>     </form> If you note the code snippet above, I have included the scripts in the top with the attachMode set to “optout” and for the last TextBox, I have mentioned the MicrosoftILITWebAttach="false” attribute to make it accept English input.   Additionally, you also need to add the “Microsoft Indic Language Input Tool attribution image” to your web page as a courtesy to the team that developed this feature.  It would basically add a image saying “Transliteration by Microsoft” similar to a Copy Right image.  You can see the screen shot below where I have typed it in Tamil.  In that you will notice that the password field behaves as expected and the last field accepts English Text.  You can also notice the icon that comes in the first textbox that indicates that, the field is going to accept indic text.   This sample is using Tamil, but you can pretty much do it for Hindi, Telugu, Kannada, Marathi, Bengali etc.,   The website for getting the Indic script and other instructions is http://specials.msn.co.in/ilit/WebEmbed.aspx?language=Tamil You can replace the querystring value “Tamil” to other languages as mentioned above to get the respective script. This also works for plain HTML based websites and doesn’t necessarily need you to use ASP.NET to achieve the functionality. Note that, this form is not completely localized.  This is transliterated.  You can add label controls for FirstName, LastName indication etc., and use the Visual Studio tools to localize and get those values from resource files.  In the resource files, you can enter the text in different languages to make this a truly localized page.  If you just want to download the Indic Tool Desktop version (that can be used for typing in Word, Excel, pretty much any input area), you can download it from http://specials.msn.co.in/ilit/  In the same page, there is also a web version where you can type and get text then and there if you dont want to install the desktop version. So, go ahead, download / use them in your websites and enjoy the power of Indic. Cheers !!!

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  • JDeveloper and Upgrading Your JDK on Ubuntu

    - by Duncan Mills
    One little gotcha, if you, as I did recently, upgrade your JDK on Ubuntu then you may have to make sure you reflect that change in a couple of places for JDeveloper to stay happy. Assuming that you've installed from the jar version of the JDeveloper installer, then the JDK that you specified at install time will be recorded in the .jdev_jdk file in your home directory.However, be aware that this is not the only reference to the absolute path of the JDK. When you run the embedded WebLogic for the first time then the .jdeveloper/system11.1.1.3.37.56.60/DefaultDomain/bin/startWebLogic.shscript will be created, and associated with that, the setDomainEnv.sh script in the same directory. So, if you do want to change the JDK location be sure to change this file as well. (or of course do everything with symbolic links)

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  • JAX-RS 2.0 Early Draft - Third Edition Available

    - by arungupta
    JAX-RS 2.0 Early Draft Third Edition is now available. This updated draft include new samples explaining the features and clarifications in content-negotiation, discovery of providers, client-side API, filters and entity interceptors and several other sections. Provide feedback to users@jax-rs-spec. Jersey 2.0, the Reference Implementation of JAX-RS 2.0, released their fourth milestone a few days ago as well. Several features have already been implemented there. Note, this is an early development preview and several parts of the API and implementation are still evolving. Feel like trying it out? Simply go to Maven Central (of course none of this is production quality at this point). The latest JAX-RS Javadocs and Jersey 2.0 API docs are good starting points to explore. And provide them feedback at [email protected] or @gf_jersey.

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  • SQL SERVER – Retrieving Random Rows from Table Using NEWID()

    - by pinaldave
    I have previously written about how to get random rows from SQL Server. SQL SERVER – Generate A Single Random Number for Range of Rows of Any Table – Very interesting Question from Reader SQL SERVER – Random Number Generator Script – SQL Query However, I have not blogged about following trick before. Let me share the trick here as well. You can generate random scripts using following methods as well. USE AdventureWorks2012 GO -- Method 1 SELECT TOP 100 * FROM Sales.SalesOrderDetail ORDER BY NEWID() GO -- Method 2 SELECT TOP 100 * FROM Sales.SalesOrderDetail ORDER BY CHECKSUM(NEWID()) GO You will notice that using NEWID() in the ORDER BY will return random rows in the result set. How many of you knew this trick? You can run above script multiple times and it will give random rows every single time. Reference: Pinal Dave (http://blog.sqlauthority.com)   Filed under: PostADay, SQL, SQL Authority, SQL Function, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • OpenGL Learning Material (that's up to date)

    - by Sauron
    So im sure there are topics on this, but alot of them list older material. And the last book: http://www.amazon.com/OpenGL-SuperBible-Comprehensive-Tutorial-Reference/dp/0321712617/ref=sr_1_1?ie=UTF8&qid=1346116133&sr=8-1&keywords=opengl REALLY REALLY disappointed me. I DO NOT want to use someone else's library to learn this stuff, that bothers me SOOO much. So I was hoping there was a newer book that goes into detail, and doesn't use some sort of library "Hiding" everything from you. Or should I just look at older material? If so....anything thats not "too" out of date. Terrain tutorials are a plus (that's kinda my "goal"). Thanks

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  • Link tracking: Amazon or Google way

    - by Howard
    When doing a shopping site, the best way is to reference some successful stores, like Amazon. In the area of link tracking, for example, to see which section of your frontpage yield better conversion: Amazon way: Generate an unique URL for each link in the frontpage, such as http://www.amazon.com/gp/product/B0083Q04IQ/ref=s9_pop_gw_g424_ir04/175-6575053-9292830?pf_rd_m=ATVPDKIKX0DER&pf_rd_s=center-2&pf_rd_r=0AMJCKBBQA63EP0XHB86&pf_rd_t=101&pf_rd_p=1263340922&pf_rd_i=507846 Google way Use Google Analytics <a href="/products/abc" onClick="javascript: pageTracker._trackPageview('/from-main-menu/products/abc');"> WHat are the pros and cons with the above two approaches (besides Google require JS support)?

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  • How is the terrain generated in Commandos and Commandos game clones/look-alikes?

    - by teodron
    The Commandos series of games and its similar western counterpart, Desperados, use a mix of 2D and 3D elements to achieve a very pleasing and immersive atmosphere. Apart from the concept that alone made the series a best-seller, the graphics eye-candy was also a much appreciated asset of that game. I was very curious on what was the technique used to model and adorn the realistic terrains in those titles? Below are some screenshots that could be relevant as a reference for whomever has a candidate answer: The tiny details and patternless distribution of ornamental textures make me think that these terrains were not generated using a standard heightmap-blendmap method.

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  • October OTN Member Offers

    - by Cassandra Clark - OTN
    Oracle OpenWorld and JavaOne were GREAT!  Thanks to all who dropped by one or both OTN Lounges (Howard St Tent and Java DemoGrounds).  Don't think we forgot about the OTN Discounts for October.  Read on to see what was added or just go to the OTN Member Discount page. Oracle Store is back with a 10% discount! Oracle Press added some new titles - 40% Off Latest Titles! OCA Java SE 7 Programmer I Study Guide (Exam 1Z0-803)  Oracle Solaris 11 System Administration: The Complete Reference Packt Publishing, Apress, Manning and Safari all extended their September offers!   Happy buying!

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  • How to share my wireless connection to other wireless devices

    - by user89464
    I am aware that I can share my wired internet connection to other devices wirelessly, but what I need now is a little more complex. I am limited to one device over the wifi but would like my macbook to have internet as well. It's in another room so ethernet is not really an option. I really would like to share the wireless from my ubuntu (it's on more) to other wireless devices. After some light googling I can't find anything even remotely useful as they all involve an ethernet cable at some point. Has anyone here had any luck with anything similar? I am running 12.04 LTS just for reference and have a Belkin G wireless USB device. If anyone knows a possible procedure I can find out about the chipset etc. if needed. I understand there may be hardware limitations.

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  • Interacting with scene from controller/app delegate cocos2d

    - by cjroebuck
    I'm attempting to make my first cocos2d (for iphone) multiplayer game and having difficulty understanding how to interact with a scene once it is running. The game is a simple turn-based one and so I have a GameController class which co-ordinates the rounds. I also have a GameScene class which is the actual scene that is displayed during a round of the game. The basic interaction I need is for the GameController to be able to pass messages to the GameScene class.. such as StartRound/StopRound etc. The thing that complicates this is that I am loading the GameScene with a LoadingScene class which simply initialises the scene and replaces the current scene with this one, so there is no reference from GameController to GameScene, so passing messages is quite tricky. Does anyone have any ways to get around this, ideally I would still like to use a Loading class as it smooths out the memory hit when replacing scenes.

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  • How do I dynamically reload content files?

    - by Kikaimaru
    Is there a relatively simple way to dynamically reload content files, such as effect files? I know I can do the following: Detect change of file Run content pipeline to rebuild that specific file Unload ALL content that was loaded Load all content And use double references to reference content files. The problem is with step 3 (and step 2 isn't that nice either). I need to unload everything because if I have model Hero.x which references Model.fx effect, and I change the Model.fx file, I need to reload the Hero.x file which will then call LoadExternalReference on Model.fx. Has someone managed to make this work without rewriting the whole ContentManager (and every ContentReader) and tracking calls to LoadExternalReference?

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  • design pattern for unit testing?

    - by Maddy.Shik
    I am beginner in developing test cases, and want to follow good patterns for developing test cases rather than following some person or company's specific ideas. Some people don't make test cases and just develop the way their senior have done in their projects. I am facing lot problems like object dependencies (when want to test method which persist A object i have to first persist B object since A is child of B). Please suggest some good books or sites preferably for learning design pattern for unit test cases. Or reference to some good source code or some discussion for Dos and Donts will do wonder. So that i can avoid doing mistakes be learning from experience of others.

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  • Heading in the Right Direction: Garmin Exadata adoption

    - by Javier Puerta
    A pioneer in global positioning system (GPS) navigation, Garmin International Inc. has been adopting Exadata to support the infrastructure that powered the company’s Oracle Advanced Supply Chain Planning, but also the company’s fitness segment, which provides customers with an online platform to store, retrieve, and interact with data captured using Garmin fitness products. The environment, which is built on an Oracle Database, processes approximately 40 million queries per week. Prior to using Oracle Exadata Database Machine, as the online offering grew in popularity, it began to face reliability issues that had negatively impacted the customer experience. We included the video testimonial in a previous post. Now you can find the a complete set of materials about this customer story Garmin Customer Reference Garmin video testimonial:  Garmin Consolidates on Exadata for 50% Performance Boost Profit Magazine article:  Heading in the Right Direction

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  • Getting My Head Around Immutability

    - by Michael Mangold
    I'm new to object-oriented programming, and one concept that has been taking me a while to grasp is immutability. I think the light bulb went off last night but I want to verify: When I come across statements that an immutable object cannot be changed, I'm puzzled because I can, for instance, do the following: NSString *myName = @"Bob"; myName = @"Mike"; There, I just changed myName, of immutable type NSString. My problem is that the word, "object" can refer to the physical object in memory, or the abstraction, "myName." The former definition applies to the concept of immutability. As for the variable, a more clear (to me) definition of immutability is that the value of an immutable object can only be changed by also changing its location in memory, i.e. its reference (also known as its pointer). Is this correct, or am I still lost in the woods?

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  • How to secure robots.txt file?

    - by CompilingCyborg
    I would like for User-agents to index my relative pages only without accessing any directory on my server. As initial thought, i had this version in mind: User-agent: * Disallow: */* Sitemap: http://www.mydomain.com/sitemap.xml My Questions: Is it correct to block all directories like that - Disallow: */*? Would still search engines be able to see and index my sitemap if i disallowed all directories? What are the best practices for securing the robots.txt file? For Reference: Here is a good tutorial for robots.txt #Add this if you want to stop Alexa from indexing your site. User-agent: ia_archiver Disallow: / #Add this to stop duggmirror User-agent: duggmirror Disallow: / #Add this to allow specific agents User-agent: Googlebot Disallow: #Add this to allow all agents while blocking specific directories User-agent: * Disallow: /cgi-bin/ Disallow: /*?*

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  • Enablement 2.0 Get Specialized!

    - by michaela.seika(at)oracle.com
      Check the new OPN Certified Specialist Exam Study Guides – your quick reference to the training options to guide partners pass OPN Specialist Exams! What are the advantages of the Exam Study Guides? Cover the Implementation Specialist Exams that count towards OPN Specialization program. Capture Exam Topics, Exam Objectives and Training Options. Define the Exam Objectives by learner or practitioner level of knowledge: Learner-level: questions require the candidate to recall information to derive the correct answer Practitioner-level: questions require the candidate to derive the correct answer from an application of their knowledge. Map by each Exam Topic the alternative training options that are available at Oracle. Where to find the Exam Study Guides? On Enablement 2.0 > Spotlight On each Knowledge Zone > Implement On each Specialist Implementation Guided Learning Path For More Information Oracle Certification Program Beta Exams OPN Certified Specialist Exams OPN Certified Specialist FAQ Contact Us Please direct any inquiries you may have to Oracle Partner Enablement team at [email protected].

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  • Dynamic MMap ran out of room when trying to sudo apt-get anything

    - by user1610406
    I was having an error in Update Manager that asks me to do a partial upgrade and it fails. Now I can't sudo apt-get install anything. I tried to fix it, and now I can't sudo apt-get anything. Every time, I get this output: Reading package lists... Error! E: Dynamic MMap ran out of room. Please increase the size of APT::Cache-Limit. Current value: 25165824. (man 5 apt.conf) E: Error occurred while processing libuptimed0 (NewVersion1) E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_lucid_universe_binary-i386_Packages W: Unable to munmap E: The package lists or status file could not be parsed or opened. I have no idea why this is happening or how to fix it, and I fear that if I try something that probably doesn't work that it will make my problem worse. (Just for reference I am currently running 10.04 (Lucid) on my machine.)

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  • Knowing your user is key--Part 1: Motivation

    - by erikanollwebb
    I was thinking where the best place to start in this blog would be and finally came back to a theme that I think is pretty critical--successful gamification in the enterprise comes down to knowing your user.  Lots of folks will say that gamification is about understanding that everyone is a gamer.  But at least in my org, that argument won't play for a lot of people.  Pun intentional.  It's not that I don't see the attraction to the idea--really, very few people play no games at all.  If they don't play video games, they might play solitaire on their computer.  They may play card games, or some type of sport.  Mario Herger has some great facts on how much game playing there is going on at his Enterprise-Gamification.com website. But at the end of the day, I can't sell that into my organization well.  We are Oracle.  We make big, serious software designed run your whole business.  We don't make Angry Birds out of your financial reporting tools.  So I stick with the argument that works better.  Gamification techniques are really just good principals of user experience packaged a little differently.  Feedback?  We already know feedback is important when using software.  Progress indicators?  Got that too.  Game mechanics may package things in a more explicit way but it's not really "new".  To know how to use game mechanics, and what a user experience team is important for, is totally understanding who our users are and what they are motivated by. For several years, I taught college psychology courses, including Motivation.  Motivation is generally broken down into intrinsic and extrinsic motivation.  There's intrinsic, which comes from within the individual.  And there's extrinsic, which comes from outside the individual.  Intrinsic motivation is that motivation that comes from just a general sense of pleasure in the doing of something.  For example, I like to cook.  I like to cook a lot.  The kind of cooking I think is just fun makes other people--people who don't like to cook--cringe.  Like the cake I made this week--the star-spangled rhapsody from The Cake Bible: two layers of meringue, two layers of genoise flavored with a raspberry eau de vie syrup, whipped cream with berries and a mousseline buttercream, also flavored with raspberry liqueur and topped with fresh raspberries and blueberries. I love cooking--I ask for cooking tools for my birthday and Christmas, I take classes like sushi making and knife skills for fun.  I like reading about you can make an emulsion of egg yolks, melted butter and lemon, cook slowly and transform them into a sauce hollandaise (my use of all the egg yolks that didn't go into the aforementioned cake).  And while it's nice when people like what I cook, I don't do it for that.  I do it because I think it's fun.  My former boss, Ultan Ó Broin, loves to fish in the sea off the coast of Ireland.  Not because he gets prizes for it, or awards, but because it's fun.  To quote a note he sent me today when I asked if having been recently ill kept him from the beginning of mackerel season, he told me he had already been out and said "I can fish when on a deathbed" (read more of Ultan's work, see his blogs on User Assistance and Translation.). That's not the kind of intensity you get about something you don't like to do.  I'm sure you can think of something you do just because you like it. So how does that relate to gamification?  Gamification in the enterprise space is about uncovering the game within work.  Gamification is about tapping into things people already find motivating.  But to do that, you need to know what that user is motivated by. Customer Relationship Management (CRM) is one of those areas where over-the-top gamification seems to work (not to plug a competitor in this space, but you can search on what Bunchball* has done with a company just a little north of us on 101 for the CRM crowd).  Sales people are naturally competitive and thrive on that plus recognition of their sales work.  You can use lots of game mechanics like leaderboards and challenges and scorecards with this type of user and they love it.  Show my whole org I'm leading in sales for the quarter?  Bring it on!  However, take the average accountant and show how much general ledger activity they have done in the last week and expose it to their whole org on a leaderboard and I think you'd see a lot of people looking for a new job.  Why?  Because in general, accountants aren't extraverts who thrive on competition in their work.  That doesn't mean there aren't game mechanics that would work for them, but they won't be the same game mechanics that work for sales people.  It's a different type of user and they are motivated by different things. To break this up, I'll stop here and post now.  I'll pick this thread up in the next post. Thoughts? Questions? *Disclosure: To my knowledge, Oracle has no relationship with Bunchball at this point in time.

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  • How to measure the conversion rate of your Amazon affiliate program?

    - by user359650
    I plan on selling products through the Amazon affiliate program. What I know I can track is: -what products people view on my website (default Google Analytics pageview behaviour). -what affiliate links people click on my website (with GA _trackEvent). What am I missing is: -what products people end up buying after clicking on the affiliate links. Does the Amazon affiliate program offers you any mechanism for linking a purchase with some data from your website? I noticed that I was able to add custom parameters and values to my affiliate links and the link checker was still happy with them, if Amazon gave the links that initiated an order then I would be able to cross reference the orders using custom parameters...

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  • Which hosted chat solutions offer the following?

    - by David
    I am looking for a chat room solution similar to the one on StackExchange to facilitate more responsive communication between the contributors on Open-Org.com. My criteria are the following: No Flash (this rules out more than half) Full history (meaning that it is possible to access all previous conversation for future reference. Very customizable No ugly IRC stuff filling up the chat view (I do not want to see who joined an who left etc.) No private conversations possible (this is just not in the spirit of Open-org.com) A hosted solution with a reasonable price. These criteria are so different from this question, so this is not a duplicate question. The service which matches this the closest is Chatroll.com. However, at 199$ per month their prices are outrageous.

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  • Computer Networks UNISA - Chap 8 &ndash; Wireless Networking

    - by MarkPearl
    After reading this section you should be able to Explain how nodes exchange wireless signals Identify potential obstacles to successful transmission and their repercussions, such as interference and reflection Understand WLAN architecture Specify the characteristics of popular WLAN transmission methods including 802.11 a/b/g/n Install and configure wireless access points and their clients Describe wireless MAN and WAN technologies, including 802.16 and satellite communications The Wireless Spectrum All wireless signals are carried through the air by electromagnetic waves. The wireless spectrum is a continuum of the electromagnetic waves used for data and voice communication. The wireless spectrum falls between 9KHZ and 300 GHZ. Characteristics of Wireless Transmission Antennas Each type of wireless service requires an antenna specifically designed for that service. The service’s specification determine the antenna’s power output, frequency, and radiation pattern. A directional antenna issues wireless signals along a single direction. An omnidirectional antenna issues and receives wireless signals with equal strength and clarity in all directions The geographical area that an antenna or wireless system can reach is known as its range Signal Propagation LOS (line of sight) uses the least amount of energy and results in the reception of the clearest possible signal. When there is an obstacle in the way, the signal may… pass through the object or be obsrobed by the object or may be subject to reflection, diffraction or scattering. Reflection – waves encounter an object and bounces off it. Diffraction – signal splits into secondary waves when it encounters an obstruction Scattering – is the diffusion or the reflection in multiple different directions of a signal Signal Degradation Fading occurs as a signal hits various objects. Because of fading, the strength of the signal that reaches the receiver is lower than the transmitted signal strength. The further a signal moves from its source, the weaker it gets (this is called attenuation) Signals are also affected by noise – the electromagnetic interference) Interference can distort and weaken a wireless signal in the same way that noise distorts and weakens a wired signal. Frequency Ranges Older wireless devices used the 2.4 GHZ band to send and receive signals. This had 11 communication channels that are unlicensed. Newer wireless devices can also use the 5 GHZ band which has 24 unlicensed bands Narrowband, Broadband, and Spread Spectrum Signals Narrowband – a transmitter concentrates the signal energy at a single frequency or in a very small range of frequencies Broadband – uses a relatively wide band of the wireless spectrum and offers higher throughputs than narrowband technologies The use of multiple frequencies to transmit a signal is known as spread-spectrum technology. In other words a signal never stays continuously within one frequency range during its transmission. One specific implementation of spread spectrum is FHSS (frequency hoping spread spectrum). Another type is known as DSS (direct sequence spread spectrum) Fixed vs. Mobile Each type of wireless communication falls into one of two categories Fixed – the location of the transmitted and receiver do not move (results in energy saved because weaker signal strength is possible with directional antennas) Mobile – the location can change WLAN (Wireless LAN) Architecture There are two main types of arrangements Adhoc – data is sent directly between devices – good for small local devices Infrastructure mode – a wireless access point is placed centrally, that all devices connect with 802.11 WLANs The most popular wireless standards used on contemporary LANs are those developed by IEEE’s 802.11 committee. Over the years several distinct standards related to wireless networking have been released. Four of the best known standards are also referred to as Wi-Fi. They are…. 802.11b 802.11a 802.11g 802.11n These four standards share many characteristics. i.e. All 4 use half duplex signalling Follow the same access method Access Method 802.11 standards specify the use of CSMA/CA (Carrier Sense Multiple Access with Collision Avoidance) to access a shared medium. Using CSMA/CA before a station begins to send data on an 802.11 network, it checks for existing wireless transmissions. If the source node detects no transmission activity on the network, it waits a brief period of time and then sends its transmission. If the source does detect activity, it waits a brief period of time before checking again. The destination node receives the transmission and, after verifying its accuracy, issues an acknowledgement (ACT) packet to the source. If the source receives the ACK it assumes the transmission was successful, – if it does not receive an ACK it assumes the transmission failed and sends it again. Association Two types of scanning… Active – station transmits a special frame, known as a prove, on all available channels within its frequency range. When an access point finds the probe frame, it issues a probe response. Passive – wireless station listens on all channels within its frequency range for a special signal, known as a beacon frame, issued from an access point – the beacon frame contains information necessary to connect to the point. Re-association occurs when a mobile user moves out of one access point’s range and into the range of another. Frames Read page 378 – 381 about frames and specific 802.11 protocols Bluetooth Networks Sony Ericson originally invented the Bluetooth technology in the early 1990s. In 1998 other manufacturers joined Ericsson in the Special Interest Group (SIG) whose aim was to refine and standardize the technology. Bluetooth was designed to be used on small networks composed of personal communications devices. It has become popular wireless technology for communicating among cellular telephones, phone headsets, etc. Wireless WANs and Internet Access Refer to pages 396 – 402 of the textbook for details.

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  • Mixing Forms and Token Authentication in a single ASP.NET Application (the Details)

    - by Your DisplayName here!
    The scenario described in my last post works because of the design around HTTP modules in ASP.NET. Authentication related modules (like Forms authentication and WIF WS-Fed/Sessions) typically subscribe to three events in the pipeline – AuthenticateRequest/PostAuthenticateRequest for pre-processing and EndRequest for post-processing (like making redirects to a login page). In the pre-processing stage it is the modules’ job to determine the identity of the client based on incoming HTTP details (like a header, cookie, form post) and set HttpContext.User and Thread.CurrentPrincipal. The actual page (in the ExecuteHandler event) “sees” the identity that the last module has set. So in our case there are three modules in effect: FormsAuthenticationModule (AuthenticateRequest, EndRequest) WSFederationAuthenticationModule (AuthenticateRequest, PostAuthenticateRequest, EndRequest) SessionAuthenticationModule (AuthenticateRequest, PostAuthenticateRequest) So let’s have a look at the different scenario we have when mixing Forms auth and WS-Federation. Anoymous request to unprotected resource This is the easiest case. Since there is no WIF session cookie or a FormsAuth cookie, these modules do nothing. The WSFed module creates an anonymous ClaimsPrincipal and calls the registered ClaimsAuthenticationManager (if any) to transform it. The result (by default an anonymous ClaimsPrincipal) gets set. Anonymous request to FormsAuth protected resource This is the scenario where an anonymous user tries to access a FormsAuth protected resource for the first time. The principal is anonymous and before the page gets rendered, the Authorize attribute kicks in. The attribute determines that the user needs authentication and therefor sets a 401 status code and ends the request. Now execution jumps to the EndRequest event, where the FormsAuth module takes over. The module then converts the 401 to a redirect (302) to the forms login page. If authentication is successful, the login page sets the FormsAuth cookie.   FormsAuth authenticated request to a FormsAuth protected resource Now a FormsAuth cookie is present, which gets validated by the FormsAuth module. This cookie gets turned into a GenericPrincipal/FormsIdentity combination. The WS-Fed module turns the principal into a ClaimsPrincipal and calls the registered ClaimsAuthenticationManager. The outcome of that gets set on the context. Anonymous request to STS protected resource This time the anonymous user tries to access an STS protected resource (a controller decorated with the RequireTokenAuthentication attribute). The attribute determines that the user needs STS authentication by checking the authentication type on the current principal. If this is not Federation, the redirect to the STS will be made. After successful authentication at the STS, the STS posts the token back to the application (using WS-Federation syntax). Postback from STS authentication After the postback, the WS-Fed module finds the token response and validates the contained token. If successful, the token gets transformed by the ClaimsAuthenticationManager, and the outcome is a) stored in a session cookie, and b) set on the context. STS authenticated request to an STS protected resource This time the WIF Session authentication module kicks in because it can find the previously issued session cookie. The module re-hydrates the ClaimsPrincipal from the cookie and sets it.     FormsAuth and STS authenticated request to a protected resource This is kind of an odd case – e.g. the user first authenticated using Forms and after that using the STS. This time the FormsAuth module does its work, and then afterwards the session module stomps over the context with the session principal. In other words, the STS identity wins.   What about roles? A common way to set roles in ASP.NET is to use the role manager feature. There is a corresponding HTTP module for that (RoleManagerModule) that handles PostAuthenticateRequest. Does this collide with the above combinations? No it doesn’t! When the WS-Fed module turns existing principals into a ClaimsPrincipal (like it did with the FormsIdentity), it also checks for RolePrincipal (which is the principal type created by role manager), and turns the roles in role claims. Nice! But as you can see in the last scenario above, this might result in unnecessary work, so I would rather recommend consolidating all role work (and other claims transformations) into the ClaimsAuthenticationManager. In there you can check for the authentication type of the incoming principal and act accordingly. HTH

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  • EclipseLink 2.4 Released: RESTful Persistence, Tenant Isolation, NoSQL, and JSON

    - by arungupta
    EclipseLink 2.4 is released as part of Eclipse Juno release train. In addition to providing the Reference Implementation for JPA 2.0, the key features in the release are: RESTful Persistence - Expose Java Persistence units over REST using either JSON or XML Tenant Isolation - Manage entities for multiple tenants in the same application NoSQL - NoSQL support for MongoDB and Oracle NoSQL JSON - Marshaling and unmarshaling of JSON object Here is the complete list of bugs fixed in this release. The landing page provide the complete list of documentation and examples. Read Doug Clarke's blog for a color commentary as well. This release is already integrated in the latest GlassFish 4.0 promoted build. Try the functionality and give us feedback at GlassFish Forum or EclipseLink Forum.

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  • Unity3D problem. Bullets fall down instead of flying like they should

    - by user2342080
    I used this tutorial as a reference. http://www.youtube.com/watch?v=3L8eaoyZ0Go My problem is that whenever I play the game, EVERYTHING works but the bullets. It just falls down instead of flying forward. This is the flash version of the game: http://v1k.me/swf/ Can some one help me out? Should I upload the project? This is my "Shoot.js": public var bulletPrefab : Transform; public var bulletSpeed : float = 20; function Update() { if(Input.GetMouseButton(0)) { if(bulletPrefab || bulletSpeed) { var bulletCreate = Instantiate(bulletPrefab, GameObject.Find("SpawnPoint").transform.position, Quaternion.identity); bulletCreate.rigidbody.AddForce(transform.forward * bulletSpeed); } } }

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