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  • SQLRally Nordic and SQLRally Amsterdam: Wrap Up and Demos

    - by Adam Machanic
    First and foremost : Huge thanks, and huge apologies, to everyone who attended my sessions at these events. I promised to post materials last week, and there is no good excuse for tardiness. My dog did not eat my computer. I don't have a dog. And if I did, she would far prefer a nice rib eye to a hard chunk of plastic. Now, on to the purpose of this post... Last week I was lucky enough to have a first visit to each of two amazing cities, Stockholm and Amsterdam. Both cities, as mentioned previously...(read more)

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  • How are Programing Language Designed?

    - by Anteater7171
    After doing a bit of programing, I've become quite curious on language design itself. I'm still a novice (I've been doing it for about a year), so the majority of my code pertains to only two fields (GUI design in Python and basic algorithms in C/C++). I have become intrigued with how the actual languages themselves are written. I mean this in both senses. Such as how it was literally written (ie, what language the language was written in). As well as various features like white spacing (Python) or object orientation (C++ and Python). Where would one start learning how to write a language? What are some of the fundamentals of language design, things that would make it a "complete" language?

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  • Best practice for storing HTML coming from text fields to a database?

    - by user1767270
    I have an application that allows users to edit certain parts of text and then email that out. My question is what is the best way to store this in a Microsoft SQL Server database. Right now I have two tables, one holding the HTML data and one holding the plain text data. When the user saves the info, it replaces newlines with br's and puts it in the HTML-conntaining table and then puts the regular text in the other table. This way the text box has the newlines when they go to edit, but the table that contains the HTML data, has the BR's. This seems like a silly way to do things. What would be the best practice? Thanks.

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  • How to set-up DSL dialer for Ubuntu 12.04 LTS

    - by Mohammad Yaseen
    I have just installed Ubuntu 12.04 LTS and I'm unable to get my DSL dialer working properly. To set this up in Windows 7 I had to do following: Control Panel --- Network and Intertnet Network and sharing center --- Setup a new network or connection Connect to the internet --- Broadband PPPoE Enter username and Password.. CLick 'Connect' and Done. I am doing following steps in Ubuntu with no luck: Click on 'Two Arrows' (i don't know what they are called) on upper right corner. Configure VPN --- DSL tab --- Add Then I entered username, password, MAC address and Clone MAC address (copied from Auto Ethernet). Save The same set up used to work with Ubuntu 10.10 but it is not working here. Now whenever I click on DSL Connection 1 to connect dialer 'Auto Ethernet' gets disconneted and I end up with no Internet connection. I am new to Ubuntu, Please suggest some easy steps. I have installed ubuntu alongside windows. And dialer works fine in Windows environment, i am writing this in Windows .

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  • CSS variable height columns [migrated]

    - by Rob
    I have created a website, www.unionfamilies.com. I have a header, a main section consisting of two columns, and a footer. Currently, I have specified heights for header, main, footer, etc. I would like to make the site so the header stays on top, the columns adjust to match the height of the longest column, and the footer stays at the bottom. Can someone help me with this? I am new to CSS, so please be patient. Thank you.

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  • OT: Airlines and Podcasts

    - by Greg Low
    Those that know me know that I spend an inordinate amount of time on airlines. I also love podcasts, as you can tell from my www.sqldownunder.com site and show. So anything that combines the two is just awesome. Fly With Joe fits that perfectly. Joe D'Eon provides great insights in his show. I was sad last year that he hadn't posted many shows. I've also been quiet for a couple of months (but that's about to change with a bunch of SQL Server 2008 R2 shows). But I've been so pleased that Joe's got...(read more)

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  • Would knowing Python help with creating iPhone applications?

    - by Josh
    Here is what the apple site says: With Snow Leopard, Mac OS X makes it easy to use scripting languages as full application development tools. Snow Leopard ships with support for the RubyCocoa Bridge and the PyObjC bridge. These two bridges give developers access not only to system APIs, but to Cocoa frameworks such as AppKit and Core Data, enabling you to build fully native Mac OS X applications in Ruby or Python. The RubyCocoa and PyObjC bridges allow you to freely mix code written in Objective-C with code written in the scripting language. You can quickly build prototypes and then optimise by implementing performance-critical pieces in Objective-C. How could Python help in this case?

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  • Software Design for Product Verticals and Service Verticals

    - by Rachel
    In every industry there are two verticals Product Vertical and Service Vertical, so my question is: How does design approach changes while designing Software for Product Vertical as compared to developing Software for Service Vertical ? What are the pros and cons for each case ? Also, in case of Product Vertical, How you go about designing Product or Features and what are steps involved ? Lastly, I was reading How Facebook Ships Code article and it appears that Product Managers have very little influence on how Product is developed and responsibility lies mainly with the Developer for the feature. So is this good practice and why one would go for this approach ? What would be your comment on this kind of approach ?

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  • Follow-up Answers for my Australia Classes

    - by Kalen Delaney
    I was out of the country for the last two weeks of March, delivering classes in Brisbane and Sydney, which were organized by WardyIT . It was a great visit and there were 24 terrific students! As is sometimes (perhaps often?) the case, there were questions posed that I couldn’t answer during class, so here are a couple of follow-up answers. 1. I brought up the fact that SQLS 2012 generates a warning message when there are ‘too many’ Virtual Log Files (VLFs) in a database. (It turns out the message...(read more)

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  • SQL SERVER – Beginning New Weekly Series – Memory Lane – #001

    - by pinaldave
    I am introducing a new series today.  This series is called “Memory Lane.”  From the last six years and 2,300 articles, there are fantastic articles I keep revisiting.  Sometimes when I read old blog posts I think I should have included something or added a bit more to the topic.  But for many articles, I still feel they are fantastic (even after six years) and could be read again and again. I have also found that after six years of blogging, readers will write to me and say “Pinal, why don’t you write about X, Y or Z.”  The answer is: I already did!  It is here on the blog, or in the comments, or possibly in one of my books.  The solution has always been there, it is simply a matter of finding it and presenting it again.  That is why I have created Memory Lane.  I will be listing the best articles from the same week of the past six years.  You will find plenty of reading material every Saturday from articles of SQLAuthority past. Here is the list of curetted articles of SQLAuthority.com across all these years. Instead of just listing all the articles I have selected a few of my most favorite articles and have listed them here with additional notes below it. Let me know which one of the following is your favorite article from memory lane. 2006 Query to Display Foreign Key Relationships and Name of the Constraint for Each Table in Database My blogging journey began with this blog post. As many of you know my journey began with creating a repository of my scripts. This was very first script which I had written to find out foreign key relationship and constraints. The same query was updated later on using the new SYS schema modification in SQL Server. Version 1: Using sys.schema Version 2: Using sys.schema and additional columns 2007 Milestone Posts – 1 Year (365 blogs) and 1 Million Views When I reached 1st week of Nov in 2007 SQLAuthority.com blog had around 365 blog posts and 1 Million Views. I was not obsessed with the statistics before but this was indeed an interesting moment for me as I was blogging for myself and did not realize that so many people are reading my blog. In year 2006 there were not many bloggers so blogging was new to me as well. I was learning it as I go. 2008 Stored Procedure WITH ENCRYPTION and Execution Plan If you have stored procedure and its code is encrypted when you execute it what will be displayed in the execution plan. There are two kinds of execution plans 1) Estimated and 2) Actual. It will be indeed interesting to know what is displayed in both the cases when Stored Procedure is encrypted. What is your guess? Now go ahead and click on here and figure out your answer. If the user is not able to login into SQL Server due to any error or issues there were two different blog post addresses the same issue here and here. 2009 It seems like Nov is the month of SQLPASS month. In 2009 on the same week I was in USA attending SQLPASS event. I had a fantastic experience attending the event. Here are the blog posts covering the subject Day 1, Day 2, Day 3, Day 4 2010 Finding the last backup time for all the databases This little script is very powerful and instantly gives details when was the last time your database backup performed. If you are reading this blog post – I say just go ahead and check if everything is alright on your server and you have all the necessary latest backup. It is better to be safe than sorrow. Version 1: Above script was improved to get more details about the database Version 2: This version of the script will include pretty much have all the backup related information in a single script. Do not miss to save it for future use. Are you a Database Administrator or a Database Developer? Three years ago I created a very small survey and the results which I have received are very interesting. The question was asking what is the profile of the visitor of that blog post and I noticed that DBA and Developers have balanced with little inclination towards Developers. Have you voted so far? If not, go ahead! 2011 New Book Released – SQL Server Interview Questions And Answers One year ago, on November 3, 2011 I published my book SQL Server Interview Questions and Answers.  The book has a lot of great reviews, and we have even received emails telling us this book was a life changer because it helped get them a great new job.  I don’t think anyone can get a job just from my book.  It was the individual who studied hard and took it seriously, and was determined to learn something new.  The book might have helped guide them and show them the topics to study, but they spent their own energy on it.  It was their own skills that helped them pass the exam. So, in this very first installment, I would like to thank the readers for accepting our book, for giving it great reviews and for using it and sharing it.  Our goal in writing this book was to help others, and it seems like we succeeded. Reference: Pinal Dave (http://blog.sqlauthority.com) Filed under: Memory Lane, PostADay, SQL, SQL Authority, SQL Query, SQL Server, SQL Tips and Tricks, T SQL, Technology

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  • SolidQ Journal for January (free and available now)

    - by Greg Low
    I've been travelling in Tasmania for a week or so and didn't get to post about the SolidQ Journal for January. It's our free monthly journal at: http://www.solidq.com/sqj . I promised to write a part two on controlling the security context of stored procedures but didn't get time to write this month. I'll rectify that very soon. However, in the meantime, the rest of the team have done a great job again. Guillermo Bas has described how to access SharePoint 2010 data through Windows Phone 7. Marino...(read more)

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  • How To View and Write To System Log Files on Ubuntu

    - by Chris Hoffman
    Linux logs a large amount of events to the disk, where they’re mostly stored in the /var/log directory in plain text. Most log entries go through the system logging daemon, syslogd, and are written to the system log. Ubuntu includes a number of ways of viewing these logs, either graphically or from the command-line. You can also write your own log messages to the system log — particularly useful in scripts. How to Banish Duplicate Photos with VisiPic How to Make Your Laptop Choose a Wired Connection Instead of Wireless HTG Explains: What Is Two-Factor Authentication and Should I Be Using It?

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  • Send arbitrary commands to modem for info

    - by mydoghasworms
    I have a USB 3G data card and modem. According to the supplier, to check the data balance on the account, I must dial a number like *89# (or whatever) from the handset. The device appears as a ppp0 interface in my network devices. How does one go about issuing commands to the modem to send the commands and receive back the information? UPDATE: OK, I found some help here: http://www.linuxquestions.org/questions/linux-hardware-18/sending-at-commands-to-a-sms-modem-372445/, but firstly, there are 3 ttyUSB devices on my system, and I assume that one of them is the 3G modem, but how can I tell? Secondly, trying to echo something to two of them says that the device is busy, which stands to reason, because I am using it to connect to the internet. Some help, please?

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  • GParted doesn't see any partition

    - by Diego
    What I am trying to do couldn't be more logical I think. I have a 40gb drive with two partitions, Xp and Ubuntu. I have dual boot, everything boots and works perfectly. I have about 9gb free in the Windows partition When I run Gparted I only see 40gb unallocated space, booting from Gparted Live CD. What the hell is going on ? I've read everywhere this is a common problem, however it has no sense something like this remains unsolved by gparted developers, considering what I am trying to do is the very basic step anybody wanting to migrate from Windows to Linux would od Something like this honestly doesn't give anything else than frustration Could anybody on this forum be so kind to explain whats' going on ? Thanks

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  • QCon SF 2011

    - by user12607987
    To San Francisco for QCon SF 2011, where I spoke on Java SE: Where We've Been, Where We're Going. QCon is much further "up the stack" than JavaOne, so has far fewer talks about the "foundation", Java SE. I thought it was important to review the features delivered in Java SE 7 before discussing what's planned for Java SE 8. This worked out well, as most of the audience were using Java SE 6. The language changes in SE 7 look small, but examining merely two of them - precise rethrow and suppressed exceptions - reveals a new exception handling idiom applicable to many thousands of Java classes. And thumbs up to the QCon organizers for the instant feedback mechanism!

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  • Lockdown Your Database Security

    - by Troy Kitch
    A new article in Oracle Magazine outlines a comprehensive defense-in-depth approach for appropriate and effective database protection. There are multiple ways attackers can disrupt the confidentiality, integrity and availability of data and therefore, putting in place layers of defense is the best measure to protect your sensitive customer and corporate data. “In most organizations, two-thirds of sensitive and regulated data resides in databases,” points out Vipin Samar, vice president of database security technologies at Oracle. “Unless the databases are protected using a multilayered security architecture, that data is at risk to be read or changed by administrators of the operating system, databases, or network, or hackers who use stolen passwords to pose as administrators. Further, hackers can exploit legitimate access to the database by using SQL injection attacks from the Web. Organizations need to mitigate all types of risks and craft a security architecture that protects their assets from attacks coming from different sources.” Register and read more in the online magazine format.

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  • What's the difference between implementing an Interface explicitly or implicitly?

    - by Rachel
    In Visual Studio I can right-click on an interface and choose to Implement Interface, or Implement Interface Explicitly. public class Test : ITest { public string Id // Generated by Implement Interface { get { throw new NotImplementedException(); } } string ITest.Id // Generated by Implement Interface Explicitly { get { throw new NotImplementedException(); } } } The only difference I see between the two is that the Interface name is added to the interface properties and methods when they're created if you choose to Implement Interface Explicitly. I find it makes the code a bit more readable since I can see where that method/property comes from, however does this make any difference in how the class is used or compiled? And does it really matter if I implement my interfaces implicitly or explicitly?

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  • First Partial Lunar Eclipse in 2010

    - by Suganya
    Following the Annular Solar Eclipse in January 2010, the next eclipse hitting the earth is partial Lunar Eclipse in June 2010. This partial Lunar eclipse is mostly visible to people in America and Pacific side.   The first Lunar Eclipse for the year 2010 occurs on 26th June with the magnitude of 0.5368 and the eclipse lasts for two and a half hours totally. This eclipse is clearly visible for those who are in Western Canada , USA and Eastern Australia. The local timings (24 Hours format) of the cities where the partial solar eclipse is visible are S.No Place Partial Eclipse Begins Partial Eclipse Ends 1 Atlanta 05:17 08:00 2 San Francisco 02:17 05:00 3 Texas 04:17 07:00 4 Los Angeles 02:17 05:00 5 Sydney 20:17 23:00 6 Osaka 19:17 22:00 Join us on Facebook to read all our stories right inside your Facebook news feed.

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  • Using GridView and DetailsView in ASP.NET MVC - Part 1

    - by bipinjoshi
    For any beginner in ASP.NET MVC the first disappointment is possibly the lack of any server controls. ASP.NET MVC divides the entire processing logic into three distinct parts namely model, view and controller. In the process views (that represent UI under MVC architecture) need to sacrifice three important features of web forms viz. Postbacks, ViewState and rich event model. Though server controls are not a recommended choice under ASP.NET MVC there are situations where you may need to use server controls. In this two part article I am going to explain, as an example, how GridView and DetailsView can be used in ASP.NET MVC without breaking the MVC pattern.http://www.bipinjoshi.net/articles/59b91531-3fb2-4504-84a4-9f52e2d65c20.aspx 

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  • How to Change Your Default Applications on Ubuntu: 4 Ways

    - by Chris Hoffman
    There are several ways to change your default applications on Ubuntu. Whether you’re changing the default application for a particular task, file type, or a system-level application like your default text editor, there’s a different place to go. Unlike on Windows, applications won’t take over existing file extensions during the installation process — they’ll just appear as an option after you install them. How to Banish Duplicate Photos with VisiPic How to Make Your Laptop Choose a Wired Connection Instead of Wireless HTG Explains: What Is Two-Factor Authentication and Should I Be Using It?

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  • Downloading stuff from Oracle: an example

    - by user12587121
    Introduction Oracle has a lot of software on offer.  Components of the stack can evolve at different rates and different versions of the components may be in use at any given time.  All this means that even the process of downloading the bits you need can be somewhat daunting.  Here, by way of example, and hopefully to convince you that there is method in the downloading madness,  we describe how to go about downloading the bits for Oracle Identity Manager  (OIM) 11.1.1.5.Firstly, a couple of preliminary points: Folks with Oracle products already installed and looking for bug fixes, patch bundles or patch sets would go directly to the Oracle support website. This Oracle document is a comprehensive description of the Oracle FMW download process and the licensing that applies to downloaded software.   Downloading Oracle Identity Manager 11.1.1.5     To be sure we download the right versions, first locate the Certification Matrix for OIM 11.1.1.5: first go to the Fusion Certification Page then go to the “System Requirements and Supported Platforms for Oracle Identity and Access Management 11gR1” link. Let’s assume you have a 64 bit Linux Machine and an Oracle database already.  Then our  goal is to end up with a list of files like the following: jdk-6u29-linux-x64.bin                    (Java JDK)V26017-01.zip                             (the Repository Creation Utility to create the DB schemas)wls1035_generic.jar                       (the Weblogic Application Server)ofm_iam_generic_11.1.1.5.0_disk1_1of1.zip (the Identity Managament bits)ofm_soa_generic_11.1.1.5.0_disk1_1of2.zip (the SOA bits)ofm_soa_generic_11.1.1.5.0_disk1_2of2.zip jdevstudio11115install.exe                (optional: JDeveloper IDE)soa-jdev-extension.zip                    (optional: SOA extensions for JDeveloper) Downloading the bits 1.    Download the Java JDK, 64 bit version 1.6.0_24+.2.    Download the RCU: here you will see that the RCU is mentioned on the Identity Management home page but no link is provided.  Do not panic.  Due to the amount and turnover of software available only the latest versions are available for download from the main Oracle site.  Over time software gets moved on to the Oracle edelivery site and it is here that we find the RCU version we require: a.    Go to edelivery: https://edelivery.oracle.com b.    Choose Pack ‘ Oracle Fusion Middleware’ and ‘Linux x86-64’ c.    Click on ‘Oracle Fusion Middleware 11g Media Pack for Linux x86-64’ d.    Download: ‘Oracle Fusion Middleware Repository Creation Utility 11g (11.1.1.5.0) for Linux x86’ (V26017.zip) 3.    Download the Weblogic Application Server: WLS 10.3.54.    Download the Oracle Identity Manager bits: one point to clarify here is that currently  the Identity Management bits come in two trains, essentially one for the Directory Services piece and the other for the Access Management and Identity Management parts.  We need to be careful not to confuse the two, in particular to be clear which of the trains is being referred to by  the documentation: a.   So, with this in mind, go to ‘ Oracle Identity and Access Management (11.1.1.5.0)’ and download Disk1. 5.    Download the SOA bits: a.    Go to the edelivery area as for the RCU and download: i.    Oracle SOA Suite 11g Patch Set 4 (11.1.1.5.0) (Part 1 of 2) ii.    Oracle SOA Suite 11g Patch Set 4 (11.1.1.5.0) (Part 2 of 2) 6.    You will want to download some development tooling (for plugins or BPEL workflow development): a.    Download Jdeveloper 11.1.1.5 (11.1.1.6 may work but best to stick to the versions that correspond to the WLS version we are using) b.    Go to the site for  SOA tools and download the SOA Composite Editor 11.1.1.5 That’s it, you may proceed to the installation. 

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  • Mod Puts Mac OS 7 On the Nook Touch

    - by Jason Fitzpatrick
    Thanks to a mac-hardware emulator for Android, it’s now possible to run Mac OS 7 on the Nook Touch (or other Android-based tablet). If you’ve been looking for some retro-goodness to dump on your Nook or tablet–Oregon Trail anyone?–this simple hack will certainly help. Hit up the link below for additional screenshots and more information. Mini vMac for Android Development Thread [via MikeCanex] HTG Explains: What Is Two-Factor Authentication and Should I Be Using It? HTG Explains: What Is Windows RT and What Does It Mean To Me? HTG Explains: How Windows 8′s Secure Boot Feature Works & What It Means for Linux

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  • College Courses through distance learning

    - by Matt
    I realize this isn't really a programming question, but didn't really know where to post this in the stackexchange and because I am a computer science major i thought id ask here. This is pretty unique to the programmer community since my degree is about 95% programming. I have 1 semester left, but i work full time. I would like to finish up in December, but to make things easier i like to take online classes whenever I can. So, my question is does anyone know of any colleges that offer distance learning courses for computer science? I have been searching around and found a few potential classes, but not sure yet. I would like to gather some classes and see what i can get approval for. Class I need: Only need one C SC 437 Geometric Algorithms C SC 445 Algorithms C SC 473 Automata Only need one C SC 452 Operating Systems C SC 453 Compilers/Systems Software While i only need of each of the above courses i still need to take two more electives. These also have to be upper 400 level classes. So i can take multiple in each category. Some other classes I can take are: CSC 447 - Green Computing CSC 425 - Computer Networking CSC 460 - Database Design CSC 466 - Computer Security I hoping to take one or two of these courses over the summer. If not, then online over the regular semester would be ok too. Any help in helping find these classes would be awesome. Maybe you went to a college that offered distance learning. Some of these classes may be considered to be graduate courses too. Descriptions are listed below if you need. Thanks! Descriptions Computer Security This is an introductory course covering the fundamentals of computer security. In particular, the course will cover basic concepts of computer security such as threat models and security policies, and will show how these concepts apply to specific areas such as communication security, software security, operating systems security, network security, web security, and hardware-based security. Computer Networking Theory and practice of computer networks, emphasizing the principles underlying the design of network software and the role of the communications system in distributed computing. Topics include routing, flow and congestion control, end-to-end protocols, and multicast. Database Design Functions of a database system. Data modeling and logical database design. Query languages and query optimization. Efficient data storage and access. Database access through standalone and web applications. Green Computing This course covers fundamental principles of energy management faced by designers of hardware, operating systems, and data centers. We will explore basic energy management option in individual components such as CPUs, network interfaces, hard drives, memory. We will further present the energy management policies at the operating system level that consider performance vs. energy saving tradeoffs. Finally we will consider large scale data centers where energy management is done at multiple layers from individual components in the system to shutting down entries subset of machines. We will also discuss energy generation and delivery and well as cooling issues in large data centers. Compilers/Systems Software Basic concepts of compilation and related systems software. Topics include lexical analysis, parsing, semantic analysis, code generation; assemblers, loaders, linkers; debuggers. Operating Systems Concepts of modern operating systems; concurrent processes; process synchronization and communication; resource allocation; kernels; deadlock; memory management; file systems. Algorithms Introduction to the design and analysis of algorithms: basic analysis techniques (asymptotics, sums, recurrences); basic design techniques (divide and conquer, dynamic programming, greedy, amortization); acquiring an algorithm repertoire (sorting, median finding, strong components, spanning trees, shortest paths, maximum flow, string matching); and handling intractability (approximation algorithms, branch and bound). Automata Introduction to models of computation (finite automata, pushdown automata, Turing machines), representations of languages (regular expressions, context-free grammars), and the basic hierarchy of languages (regular, context-free, decidable, and undecidable languages). Geometric Algorithms The study of algorithms for geometric objects, using a computational geometry approach, with an emphasis on applications for graphics, VLSI, GIS, robotics, and sensor networks. Topics may include the representation and overlaying of maps, finding nearest neighbors, solving linear programming problems, and searching geometric databases.

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  • Custom Theming now Available in Gmail

    - by Asian Angel
    This past November Google unveiled a new look for Gmail with HD themes, but you could not set up custom themes until now. Set up your new custom theme with a Light or Dark look to match up nicely with your chosen background and enjoy a more personalized experience in your inbox. This is where you will find the new custom settings on the Themes Settings Page… The confirmation screens for the new Light and Dark Custom Themes… How to Make Your Laptop Choose a Wired Connection Instead of Wireless HTG Explains: What Is Two-Factor Authentication and Should I Be Using It? HTG Explains: What Is Windows RT and What Does It Mean To Me?

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  • WPF: Timers

    - by Ilya Verbitskiy
    I believe, once your WPF application will need to execute something periodically, and today I would like to discuss how to do that. There are two possible solutions. You can use classical System.Threading.Timer class or System.Windows.Threading.DispatcherTimer class, which is the part of WPF. I have created an application to show you how to use the API.     Let’s take a look how you can implement timer using System.Threading.Timer class. First of all, it has to be initialized.   1: private Timer timer; 2:   3: public MainWindow() 4: { 5: // Form initialization code 6: 7: timer = new Timer(OnTimer, null, Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan); 8: }   Timer’s constructor accepts four parameters. The first one is the callback method which is executed when timer ticks. I will show it to you soon. The second parameter is a state which is passed to the callback. It is null because there is nothing to pass this time. The third parameter is the amount of time to delay before the callback parameter invokes its methods. I use System.Threading.Timeout helper class to represent infinite timeout which simply means the timer is not going to start at the moment. And the final fourth parameter represents the time interval between invocations of the methods referenced by callback. Infinite timeout timespan means the callback method will be executed just once. Well, the timer has been created. Let’s take a look how you can start the timer.   1: private void StartTimer(object sender, RoutedEventArgs e) 2: { 3: timer.Change(TimeSpan.Zero, new TimeSpan(0, 0, 1)); 4:   5: // Disable the start buttons and enable the reset button. 6: }   The timer is started by calling its Change method. It accepts two arguments: the amount of time to delay before the invoking the callback method and the time interval between invocations of the callback. TimeSpan.Zero means we start the timer immediately and TimeSpan(0, 0, 1) tells the timer to tick every second. There is one method hasn’t been shown yet. This is the callback method OnTimer which does a simple task: it shows current time in the center of the screen. Unfortunately you cannot simple write something like this:   1: clock.Content = DateTime.Now.ToString("hh:mm:ss");   The reason is Timer runs callback method on a separate thread, and it is not possible to access GUI controls from a non-GUI thread. You can avoid the problem using System.Windows.Threading.Dispatcher class.   1: private void OnTimer(object state) 2: { 3: Dispatcher.Invoke(() => ShowTime()); 4: } 5:   6: private void ShowTime() 7: { 8: clock.Content = DateTime.Now.ToString("hh:mm:ss"); 9: }   You can build similar application using System.Windows.Threading.DispatcherTimer class. The class represents a timer which is integrated into the Dispatcher queue. It means that your callback method is executed on GUI thread and you can write a code which updates your GUI components directly.   1: private DispatcherTimer dispatcherTimer; 2:   3: public MainWindow() 4: { 5: // Form initialization code 6:   7: dispatcherTimer = new DispatcherTimer { Interval = new TimeSpan(0, 0, 1) }; 8: dispatcherTimer.Tick += OnDispatcherTimer; 9: } Dispatcher timer has nicer and cleaner API. All you need is to specify tick interval and Tick event handler. The you just call Start method to start the timer.   private void StartDispatcher(object sender, RoutedEventArgs e) { dispatcherTimer.Start(); // Disable the start buttons and enable the reset button. } And, since the Tick event handler is executed on GUI thread, the code which sets the actual time is straightforward.   1: private void OnDispatcherTimer(object sender, EventArgs e) 2: { 3: ShowTime(); 4: } We’re almost done. Let’s take a look how to stop the timers. It is easy with the Dispatcher Timer.   1: dispatcherTimer.Stop(); And slightly more complicated with the Timer. You should use Change method again.   1: timer.Change(Timeout.InfiniteTimeSpan, Timeout.InfiniteTimeSpan); What is the best way to add timer into an application? The Dispatcher Timer has simple interface, but its advantages are disadvantages at the same time. You should not use it if your Tick event handler executes time-consuming operations. It freezes your window which it is executing the event handler method. You should think about using System.Threading.Timer in this case. The code is available on GitHub.

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