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  • How to make a Stop Motion or Time-lapse video with webcam?

    - by Seppo Erviälä
    I have a webcam that works as a v4l2 device. What is the most convenient way to capture either a stop-motion or time-lapse video? N.B. stop-motion and time-lapse are related but conceptually different. Time-lapse is where you take a photo of a scene at a set interval and then combine it into a video (that looks like it's going really fast). Stop-motion is where you control the scene and take an image for every change you make, to form an animation (eg Wallace and Grommit). An application for time-lapse needs to be able to take a photo at a set interval.

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  • PC On/Off Time Charts Windows Uptime; No Logging Necessary

    - by Jason Fitzpatrick
    Windows: PC On/Off Time is a graphical tool that displays your PC’s uptime, downtime, errors, and more all in a clear and portable package. One of the hassles of using logging tools is that you usually have to enable the logging and then wait for results to pile up before seeing anything useful (such as when you turn on the logging on your router). PC On/Off Time taps right into the event logs your Windows PC is already keeping so you get immediate access to your uptime history. If you look at the screenshot above you can see an accurate picture of the last few weeks of uptime on my computer. October 23-24 I didn’t boot down my PC, the rest of the time I hibernated it overnight when I wasn’t using it, November 1st I installed an SSD (you can see the burst of reboots and short uptimes) and then November 9th there was a brief power outage that caused an unexpected stop (the red arrows on the timeline for the 9th). The free version offers a three-week peek back into your uptime history (upgrade to the Pro version for $12.75 or for free using Trial Pay to unlock your completely uptime history).PC On/Off Time is Windows only. PC On/Off Time [via Addictive Tips] Use Amazon’s Barcode Scanner to Easily Buy Anything from Your Phone How To Migrate Windows 7 to a Solid State Drive Follow How-To Geek on Google+

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  • Why does an error appear every time I try to open the Ubuntu Software Center? [duplicate]

    - by askubuntu7639
    This question already has an answer here: How do I remove a broken software source? 3 answers There is a glitch on the Ubuntu Software Center and whenever I open it an error appears and it keeps loading and never opens. Why does this happen? I have installed Ubuntu 13.04 on a disk and partitioned it. Please help me and ask for excess information if you need it. If you know of any duplicates please show me them!! This is the output of a question someone asked me. SystemError: E:Type '<!DOCTYPE' is not known on line 1 in source list /etc/apt/sources.list.d/medibuntu.list This next output is the output of cat /etc/apt/sources.list.d/medibuntu.list </div> <div style="float:left;"> <div class="textwidget"><script type="text/javascript"><!-- google_ad_client = "ca-pub-2917661377128354"; /* 160X600 Sidebar UX */ google_ad_slot = "9908287444"; google_ad_width = 160; google_ad_height = 600; //-- Recent Comments <article> <div style="float:left; display:block; margin:0 10px 10px 0; border:1px solid #CCCCCC; padding:3px; width:35px; height:35px;"><img alt='' src='http://0.gravatar.com/avatar/ae5f4503d5f167f1cf62d3e36e8242b6?s=35&amp;d=&amp;r=G' class='avatar avatar-35 photo' height='35' width='35' /></div> <div style="float:left;"> <h4 class="author">Richard Syme</h4> <p class="meta"> <time datetime="2013-09-24" pubdate>September 24, 2013</time> | <a class="permalink" href="http://www.unixmen.com/how-to-customize-you-vlc-hot-keys/#comment-13732">#</a> </p> </div> <div class="content" style="float:left;"><p>I dont have a clear button under the hotkeys. All i want to do is get rid of all hotkeys.</p> </article> <article> <div style="float:left; display:block; margin:0 10px 10px 0; border:1px solid #CCCCCC; padding:3px; width:35px; height:35px;"><img alt='' src='http://1.gravatar.com/avatar/ffabde94437e996a506e31e981bcf8fc?s=35&amp;d=&amp;r=G' class='avatar avatar-35 photo' height='35' width='35' /></div> <div style="float:left;"> <h4 class="author">Abin Thomas Mathew</h4> <p class="meta"> <time datetime="2013-09-24" pubdate>September 24, 2013</time> | <a class="permalink" href="http://www.unixmen.com/install-lamp-server-in-centos-6-4-rhel-6-4/#comment-13727">#</a> </p> </div> <div class="content" style="float:left;"><p>Simple and easy to follow tutorial to install and start of phpMyAdmin. Thank you</p> </article> <article> <div style="float:left; display:block; margin:0 10px 10px 0; border:1px solid #CCCCCC; padding:3px; width:35px; height:35px;"><img alt='' src='http://0.gravatar.com/avatar/499ccc1154e9b8569b87413434220b91?s=35&amp;d=&amp;r=G' class='avatar avatar-35 photo' height='35' width='35' /></div> <div style="float:left;"> <h4 class="author">SK</h4> <p class="meta"> <time datetime="2013-09-24" pubdate>September 24, 2013</time> | <a class="permalink" href="http://www.unixmen.com/munich-giving-ubuntu-linux-cds-citizens/#comment-13725">#</a> </p> </div> <div class="content" style="float:left;"><p>I have Bosslinux and i used it for a while. Now i swiched to Ubuntu 13.04.</p> </article> <article> <div style="float:left; display:block; margin:0 10px 10px 0; border:1px solid #CCCCCC; padding:3px; width:35px; height:35px;"><img alt='' src='http://1.gravatar.com/avatar/3dc2f7140bdd857dcdfe815a6e29aa6b?s=35&amp;d=&amp;r=G' class='avatar avatar-35 photo' height='35' width='35' /></div> <div style="float:left;"> <h4 class="author">Anon</h4> <p class="meta"> <time datetime="2013-09-24" pubdate>September 24, 2013</time> | <a class="permalink" href="http://www.unixmen.com/linus-torvalds-talks-backdoor-linuxcon/#comment-13724">#</a> </p> </div> <div class="content" style="float:left;"><p>Do you know how much extra bloat is in Ubuntu these days? How the hell does anyone really know?</p> </article> <article> <div style="float:left; display:block; margin:0 10px 10px 0; border:1px solid #CCCCCC; padding:3px; width:35px; height:35px;"><img alt='' src='http://1.gravatar.com/avatar/9dd28d1cf5efe754fa58b53c1e6de401?s=35&amp;d=&amp;r=G' class='avatar avatar-35 photo' height='35' width='35' /></div> <div style="float:left;"> <h4 class="author"><a href="http://ambitiousgeeks.blogspot.com/" onclick="javascript:_gaq.push(['_trackEvent','outbound-commentauthor','http://ambitiousgeeks.blogspot.com']);" rel='external nofollow' class='url'>Ambition</a></h4> <p class="meta"> <time datetime="2013-09-24" pubdate>September 24, 2013</time> | <a class="permalink" href="http://www.unixmen.com/linus-torvalds-talks-backdoor-linuxcon/#comment-13723">#</a> </p> </div> <div class="content" style="float:left;"><p>True :)</p> </article> </div> <div style="float:left;"> &nbsp;<script type="text/javascript"> window.___gcfg = {lang: 'en-US'}; (function() {var po = document.createElement("script"); po.type = "text/javascript"; po.async = true;po.src = "https://apis.google.com/js/plusone.js"; var s = document.getElementsByTagName("script")[0]; s.parentNode.insertBefore(po, s); })(); <div class="execphpwidget"></div> </div> <div class="module2"> <div class="recentPost"> <h3 class="module-title2">Favorite Links</h3> <ul class='xoxo blogroll'> http://www.iticy.com']);"Cheap Hosting http://www.tuxmachines.org']);"TuxMachines.org http://www.ubuntugeek.com']);"UbuntuGeek.com http://www.stelinuxhost.com']);"Webdesign & SEO </ul> <img src="http://180016988.r.cdn77.net/wp-content/themes/unimax/images/bigLine.jpg" alt="" /> </div> </div> <div align="center" style="min-height:610px;"> <div class="execphpwidget"></div> <div class="textwidget"><a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en_US" onclick="javascript:_gaq.push(['_trackEvent','outbound-widget','http://creativecommons.org']);"><img alt="Creative Commons License" style="border-width:0" src="http://i.creativecommons.org/l/by-nc-nd/3.0/88x31.png" /></a><br />This work by <a xmlns:cc="http://creativecommons.org/ns#" href="unixmen.com" property="cc:attributionName" rel="cc:attributionURL">unixmen.com</a> is licensed under a <a rel="license" href="http://creativecommons.org/licenses/by-nc-nd/3.0/deed.en_US" >Creative Commons Attribution-NonCommercial-NoDerivs 3.0 Unported License</a>.</div> </div> </div> <!-- #primary .widget-area --> </div> Unixmen Archive Select Month September 2013 August 2013 July 2013 June 2013 May 2013 April 2013 March 2013 February 2013 January 2013 December 2012 November 2012 October 2012 September 2012 August 2012 July 2012 June 2012 May 2012 April 2012 March 2012 February 2012 January 2012 December 2011 November 2011 October 2011 September 2011 August 2011 July 2011 June 2011 May 2011 April 2011 March 2011 February 2011 January 2011 December 2010 November 2010 October 2010 September 2010 August 2010 July 2010 June 2010 May 2010 April 2010 March 2010 February 2010 January 2010 December 2009 November 2009 October 2009 September 2009 August 2009 July 2009 June 2009 May 2009 April 2009 March 2009 February 2009 January 2009 December 2008 Tags Cloudandroid apache browser Centos chrome command line Debian eyecandy Fedora firefox games gaming gnome google karmic koala kde libreoffice Linux linux distribution LinuxMint lucid lynx maverick meerkat mysql news oneiric ocelot openoffice opensource opensuse oracle ppa Precise Pangolin release RHEL security server software themes tools ubuntu unix upgrade virtualbox vlc windows wine Unixmen Twitts Firefox 16, a treat for developers http://t.co/cnd27CzT Ubuntu 12.10 ‘Quantal Quetzal’: Beta 2 Sneak Peek http://t.co/hd4LwDOy Top 5 security Myths about Linux; and their realities http://t.co/zO1LgHST About Us Advertising Sitemap Privacy Contact Us Hire Us Copyright © 2008-2013 Unixmen.com . Maintained by Unixmen . /* */ jQuery(document).on('ready post-load', easy_fancybox_handler ); http://www.w3-edge.com/wordpress-plugins/ Page Caching using apc Database Caching 3/186 queries in 0.035 seconds using apc Content Delivery Network via 180016988.r.cdn77.net Served from: www.unixmen.com @ 2013-09-25 01:38:14 by W3 Total Cache

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  • SQL analytical mash-ups deliver real-time WOW! for big data

    - by KLaker
    One of the overlooked capabilities of SQL as an analysis engine, because we all just take it for granted, is that you can mix and match analytical features to create some amazing mash-ups. As we move into the exciting world of big data these mash-ups can really deliver those "wow, I never knew that" moments. While Java is an incredibly flexible and powerful framework for managing big data there are some significant challenges in using Java and MapReduce to drive your analysis to create these "wow" discoveries. One of these "wow" moments was demonstrated at this year's OpenWorld during Andy Mendelsohn's general keynote session.  Here is the scenario - we are looking for fraudulent activities in our big data stream and in this case we identifying potentially fraudulent activities by looking for specific patterns. We using geospatial tagging of each transaction so we can create a real-time fraud-map for our business users. Where we start to move towards a "wow" moment is to extend this basic use of spatial and pattern matching, as shown in the above dashboard screen, to incorporate spatial analytics within the SQL pattern matching clause. This will allow us to compute the distance between transactions. Apologies for the quality of this screenshot….hopefully below you see where we have extended our SQL pattern matching clause to use location of each transaction and to calculate the distance between each transaction: This allows us to compare the time of the last transaction with the time of the current transaction and see if the distance between the two points is possible given the time frame. Obviously if I buy something in Florida from my favourite bike store (may be a new carbon saddle for my Trek) and then 5 minutes later the system sees my credit card details being used in Arizona there is high probability that this transaction in Arizona is actually fraudulent (I am fast on my Trek but not that fast!) and we can flag this up in real-time on our dashboard: In this post I have used the term "real-time" a couple of times and this is an important point and one of the key reasons why SQL really is the only language to use if you want to analyse  big data. One of the most important questions that comes up in every big data project is: how do we do analysis? Many enlightened customers are now realising that using Java-MapReduce to deliver analysis does not result in "wow" moments. These "wow" moments only come with SQL because it is offers a much richer environment, it is simpler to use and it is faster - which makes it possible to deliver real-time "Wow!". Below is a slide from Andy's session showing the results of a comparison of Java-MapReduce vs. SQL pattern matching to deliver our "wow" moment during our live demo.  You can watch our analytical mash-up "Wow" demo that compares the power of 12c SQL pattern matching + spatial analytics vs. Java-MapReduce  here: You can get more information about SQL Pattern Matching on our SQL Analytics home page on OTN, see here http://www.oracle.com/technetwork/database/bi-datawarehousing/sql-analytics-index-1984365.html.  You can get more information about our spatial analytics here: http://www.oracle.com/technetwork/database-options/spatialandgraph/overview/index.html If you would like to watch the full Database 12c OOW presentation see here: http://medianetwork.oracle.com/video/player/2686974264001

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  • is it better to spend my free time mastering a language I work with or learning a new one?

    - by edthethird
    I work full time on an android project and am very comfortable with both java and the android framework. On a good day, I would rate my abilities at an 8, and maybe a 7 on a bad day. I've recently found myself with more free time then I'm used too, so I have been working on a lot of personal projects. I am beginning to wonder what others think about this; is it worth my time to continue experimenting and pushing Android, or would I be better off learning another language? What do you all think about this? What would you do with more free time and energy than you know what to do with?

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  • Could spending time on Programmers.SE or Stack Overflow be substitute of good programming books for a non-beginner?

    - by Atul Goyal
    Could spending time (and actively participating) on Programmers.SE and Stack Overflow help me improve my programming skills any close to what spending time on reading a book like Code Complete 2 (which would otherwise be next in my reading list) will help. Ok, may be the answer to this question for someone who is beginning with programming might be a straight no, but I'd like to add that this question I'm asking in context when the person is familiar with programming languages but wants to improve his programming skills. I was reading this question on SO and also this book has been recommended by many others (including Jeff and Joel). To be more specific, I'd also add that even though I do programming in C, Java, Python,etc but still I'm not happy with my coding skills and reading the review of CC2 I realized I still need to improve a lot. So, basically I want to know what's the best way for me to improve programming skills - spend more time on here/SO or continue with CC2 and may be come here as and when time permits.

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  • Do you believe it's a good idea for Software Engineers to have to work as Quality Assurance Engineers for some period of time?

    - by Macy Abbey
    I believe it is. Why? I've encountered many Software Engineers who believe they are somehow superior to QA engineers. I think it may help quench this belief if they do the job of a QA engineer for some time, and realize that it is a unique and valuable skill-set of its own. The better a Software Engineer is at testing their own programs, the less cost in time their code incurs when making its way through the rest of the software development life-cycle. The more time a Software Engineer spends thinking about how a program can break, the more often they are to consider these cases as they are developing them, thus reducing bugs in the end product. A Software Engineer's definition of "complete" is always interesting...if they have spent time as a QA engineer maybe this definition will more closely match the designer of the software's. What do you all think?

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  • Unresponsive Script window pops up all the time now. Why and what to do?

    - by Christopher Jewell
    I don't know that it's for the exact same script each time, it may be. A script on this page may be busy, or it may have stopped responding. You can stop the script now, or you can continue to see if the script will complete. Script: chrome://messenger/content/folderPane.js:721 This is in association with Thunderbird I think. This doesn't just happen after I've stepped away for a long time. It happens every time I click on anything. Things keep running that I'm clicking on. Just before this started as a constant problem, I was looking at addons etc, and something in Thunderbird deactivated an old or expired JavaScript. I clicked on the update for that and after a while I found the best choice on the list and clicked download. I don't know that anything happened with that and I moved away from addons etc area. The unresponsive script window started coming back all the time. Every time I clicked on something in Thunderbird and sometimes with Firefox. I turned off Firefox and restarted, but it didn't change. Shut down Firefox and computer restarted didn't change. The unresponsive script window is persistent now.

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  • How to apply effects that occur (or change) over time to characters in a game?

    - by Joshua Harris
    So assume that I have a system that applies Effects to Characters like so: public class Character { private Collection<Effect> _effects; public void AddEffect (Effect e) { e.ApplyTo(this); _effects.Add(e); } public void RemoveEffect (Effect e) { e.RemoveFrom(this); _effects.Remove(e); } } public interface Effect { public void ApplyTo (Character character); public void RemoveFrom (Character character); } Example Effect: Armor Buff for 5 seconds. void someFunction() { // Do Stuff ... Timer armorTimer = new Timer(5 seconds); ArmorBuff armorbuff = new ArmorBuff(); character.AddEffect(armorBuff); armorTimer.Start(); // Do more stuff ... } // Some where else in code public void ArmorTimer_Complete() { character.RemoveEffect(armorBuff); } public class ArmorBuff implements Effect { public void applyTo(Character character) { character.changeArmor(20); } public void removeFrom(Character character) { character.changeArmor(-20); } } Ok, so this example would buff the Characters armor for 5 seconds. Easy to get working. But what about effects that change over the duration of the effect being applied. Two examples come to mind: Damage Over Time: 200 damage every second for 3 seconds. I could mimic this by applying an Effect that lasts for 1 second and has a counter set to 3, then when it is removed it could deal 200 damage, clone itself, decrement the counter of the clone, and apply the clone to the character. If it repeats this until the counter is 0, then you got a damage over time ability. I'm not a huge fan of this approach, but it does describe the behavior exactly. Degenerating Speed Boost: Gain a speed boost that degrades over 3 seconds until you return to your normal speed. This is a bit harder. I can basically do the same thing as above except having timers set to some portion of a second, such that they occur fast enough to give the appearance of degenerating smoothly over time (even though they are really just stepping down incrementally). I feel like you could get away with only 12 steps over a second (maybe less, I would have to test it and see), but this doesn't seem very elegant to me. The only other way to implement this effect would be to change the system so that the Character checks the _effects collection for effects that alter any of the properties any time that they are being used. I could handle this in functions like getCurrentSpeed() and getCurrentArmor(), but you can imagine how much of a hassle it would be to have that kind of overhead every time you want to do a calculation with movement speed (which would be every time you move your character). Is there a better way to deal with these kinds of effects or events?

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  • How can I make the date/time applet display on a single line?

    - by EmmyS
    I just updated from Lucid to Natty (thought it was going to be Maverick, but my About Ubuntu menu shows that it is Natty, which "was released in April 2011" - who knew the developers had mastered time travel?!) In any case, the default date/time applet in my gnome panel is now displaying on two lines (date on top of time) instead of one line like it used to. Any way to get it back on one line? I've tried the instructions shown here, but it doesn't seem to make a difference.

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  • What time to display in text messages in multiplayer game?

    - by Krom Stern
    Say I'm having a multiplayer RTS game. There's a main server for each individual game and several clients connected to it. All packets are sent to server first and then server retransmits them back to clients. Say Server is located in one time-zone and all of the clients are in different time-zones. ClientA send a text message in chat at 12:03, what times should be stamped for other clients? Should his message be uniformely timestamped by Server (12:02) or each client should timestamp the message whenever it is recieved (12:04, 16:04, 03:03, etc..). Bear in mind, that all the messages are to be in the same order on all clients, server takes care of that. So thats the question - use local time for each client or use global server time to timestamp chat messages?

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  • Mark your calendar: Get ready for the next generation of the Oracle Database!

    - by Javier Puerta
    Mark your calendar for the following upcoming webcasts for partners on the new version of the Oracle Database: Oracle Database Technical Training Webcast for Partners: July 2nd, at 17:00 CET, 4:00 pm UK - Duration: 1 hour (Access details here) Oracle Database Sales Training Webcast for EMEA Partners: July 8th, at 10:00 am CET, 9am UK - Duration: 1 hour (Details will be communicated very soon)

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  • Mark your calendar: Get ready for the next generation of the Oracle Database!

    - by Javier Puerta
    Mark your calendar for the following upcoming webcasts for partners on the new version of the Oracle Database: Oracle Database Technical Training Webcast for Partners: July 2nd, at 17:00 CET, 4:00 pm UK - Duration: 1 hour (Access details here) Oracle Database Sales Training Webcast for EMEA Partners: July 8th, at 10:00 am CET, 9am UK - Duration: 1 hour (Details will be communicated very soon)

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  • How to setup whole-disk encryption with dual boot on a MacBook Pro (generation 9,2 with 12.04)

    - by blueyed
    I can install Ubuntu 12.04 on the MacBook when using the "noapic" kernel boot option, using the alternate amd64+mac image (from http://cdimage.ubuntu.com/releases/12.04/release/ ). But after installation the screen turn sblack after trying to boot "Windows" (as named in the boot menu that shows up when holding Option/Alt during startup). I want to use whole-disk encryption and given that only one free partition is available, I have setup LVM to do so: - vg0 contains bootlv and cryptlv - in cryptlv I have setup encryption with another LVM volume group (vg1, which holds swaplv, rootlv and homelv) I have not installed Grub during installation (because I was not sure about the partition) and when trying to install it later on /dev/sda4 (which contains the outer LVM) it complained that it could not determine the file system, and --force did not help either. The black screen / behavior looks similar to starting the installer without enabling the noapic option.

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  • How do I disable/modify CPU underclocking due to temperature on a laptop with a 2nd generation core cpu?

    - by Tyson Marchuk
    I am running Ubuntu 11.04 on a tablet with a Core i5-2557M processor. When doing processing intensive tasks the CPU is forcibly under-clocked to 800MHz (instead of the normal base of 1.7GHz.) The CPU temperature is around 75 C. I have disabled CPU scaling (set governor to performance) but this seems to have no effect. I would like to either modify the behavior so that the throttling happens at 95 C or I would like to disable it altogether. Changing the min/max frequency as root using cpufreq works until the temperature rises and then it ceases to work, ignoring a minimum frequency above the 800MHz. On Windows 7 there is a 3rd party utility that can do this (ThrottleStop). Thank you.

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  • Where can I obtain a first-generation copy of the classic “Sorting out Sorting”?

    - by TML
    I cannot even figure out who made it - even the IMDB page is mostly blank, and Wikipedia does not seem to have any information about it. For such a useful film in CompSci, it strikes me as odd that the only meaningful Internet presence I can find are horrible quality copies or excerpts on YouTube. [Note: SO claims this question was migrated to here, but the URL they provide gives a 404, and I can't find it by searching Programmers.SE, so I'm re-asking...]

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  • When profiling a function for time use, what information is desirable?

    - by AaronMcSmooth
    I'm writing a program similar to Python's timeit module. The idea is to time a function by executing it anywhere from 10 to 100,000 times depending on how long it takes and then report results. I've read that the most important number is the minimum execution time because this is the number that best reflects how fast the machine can run the code in question in the absence of other programs competing for processor time and memory. This argument makes sense to me. Would you be happy with this? Would you want to know the average time or the standard deviation? Is there some other measure that you consider more important?

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  • How do developers find the time to stay on top of latest technologies?

    - by u2sonderzug
    I was a freelance web developer until circa 2004 when I started going down the management route but have decided to try to get back into development again (specifically JavaScript and HTML5 web/mobile web apps) and I really get the impression to be truly good at these and similar fast moving technologies a constant amount of time is required to be set aside to invest in getting better at existing skills in addition to learning new skills. I understand right now since I am getting back into things there is a pretty steep learning curve, but seeing how good many guys are out there - the only way I see of getting up there is putting in a serious amount of time. For those working as fulltime developers, what I am trying to understand is this - on most days, how much time in the office is spent actually grinding out code compared to learning/research. I could easily spend 2-4 hours daily getting on top of the best ways to go about doing things. Do most good developers who are employed full time invest significant hours outside of work sharpening their skills? Or maybe I'm looking at all of this completely wrong?

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  • Java code optimization on matrix windowing computes in more time

    - by rano
    I have a matrix which represents an image and I need to cycle over each pixel and for each one of those I have to compute the sum of all its neighbors, ie the pixels that belong to a window of radius rad centered on the pixel. I came up with three alternatives: The simplest way, the one that recomputes the window for each pixel The more optimized way that uses a queue to store the sums of the window columns and cycling through the columns of the matrix updates this queue by adding a new element and removing the oldes The even more optimized way that does not need to recompute the queue for each row but incrementally adjusts a previously saved one I implemented them in c++ using a queue for the second method and a combination of deques for the third (I need to iterate through their elements without destructing them) and scored their times to see if there was an actual improvement. it appears that the third method is indeed faster. Then I tried to port the code to Java (and I must admit that I'm not very comfortable with it). I used ArrayDeque for the second method and LinkedLists for the third resulting in the third being inefficient in time. Here is the simplest method in C++ (I'm not posting the java version since it is almost identical): void normalWindowing(int mat[][MAX], int cols, int rows, int rad){ int i, j; int h = 0; for (i = 0; i < rows; ++i) { for (j = 0; j < cols; j++) { h = 0; for (int ry =- rad; ry <= rad; ry++) { int y = i + ry; if (y >= 0 && y < rows) { for (int rx =- rad; rx <= rad; rx++) { int x = j + rx; if (x >= 0 && x < cols) { h += mat[y][x]; } } } } } } } Here is the second method (the one optimized through columns) in C++: void opt1Windowing(int mat[][MAX], int cols, int rows, int rad){ int i, j, h, y, col; queue<int>* q = NULL; for (i = 0; i < rows; ++i) { if (q != NULL) delete(q); q = new queue<int>(); h = 0; for (int rx = 0; rx <= rad; rx++) { if (rx < cols) { int mem = 0; for (int ry =- rad; ry <= rad; ry++) { y = i + ry; if (y >= 0 && y < rows) { mem += mat[y][rx]; } } q->push(mem); h += mem; } } for (j = 1; j < cols; j++) { col = j + rad; if (j - rad > 0) { h -= q->front(); q->pop(); } if (j + rad < cols) { int mem = 0; for (int ry =- rad; ry <= rad; ry++) { y = i + ry; if (y >= 0 && y < rows) { mem += mat[y][col]; } } q->push(mem); h += mem; } } } } And here is the Java version: public static void opt1Windowing(int [][] mat, int rad){ int i, j = 0, h, y, col; int cols = mat[0].length; int rows = mat.length; ArrayDeque<Integer> q = null; for (i = 0; i < rows; ++i) { q = new ArrayDeque<Integer>(); h = 0; for (int rx = 0; rx <= rad; rx++) { if (rx < cols) { int mem = 0; for (int ry =- rad; ry <= rad; ry++) { y = i + ry; if (y >= 0 && y < rows) { mem += mat[y][rx]; } } q.addLast(mem); h += mem; } } j = 0; for (j = 1; j < cols; j++) { col = j + rad; if (j - rad > 0) { h -= q.peekFirst(); q.pop(); } if (j + rad < cols) { int mem = 0; for (int ry =- rad; ry <= rad; ry++) { y = i + ry; if (y >= 0 && y < rows) { mem += mat[y][col]; } } q.addLast(mem); h += mem; } } } } I recognize this post will be a wall of text. Here is the third method in C++: void opt2Windowing(int mat[][MAX], int cols, int rows, int rad){ int i = 0; int j = 0; int h = 0; int hh = 0; deque< deque<int> *> * M = new deque< deque<int> *>(); for (int ry = 0; ry <= rad; ry++) { if (ry < rows) { deque<int> * q = new deque<int>(); M->push_back(q); for (int rx = 0; rx <= rad; rx++) { if (rx < cols) { int val = mat[ry][rx]; q->push_back(val); h += val; } } } } deque<int> * C = new deque<int>(M->front()->size()); deque<int> * Q = new deque<int>(M->front()->size()); deque<int> * R = new deque<int>(M->size()); deque< deque<int> *>::iterator mit; deque< deque<int> *>::iterator mstart = M->begin(); deque< deque<int> *>::iterator mend = M->end(); deque<int>::iterator rit; deque<int>::iterator rstart = R->begin(); deque<int>::iterator rend = R->end(); deque<int>::iterator cit; deque<int>::iterator cstart = C->begin(); deque<int>::iterator cend = C->end(); for (mit = mstart, rit = rstart; mit != mend, rit != rend; ++mit, ++rit) { deque<int>::iterator pit; deque<int>::iterator pstart = (* mit)->begin(); deque<int>::iterator pend = (* mit)->end(); for(cit = cstart, pit = pstart; cit != cend && pit != pend; ++cit, ++pit) { (* cit) += (* pit); (* rit) += (* pit); } } for (i = 0; i < rows; ++i) { j = 0; if (i - rad > 0) { deque<int>::iterator cit; deque<int>::iterator cstart = C->begin(); deque<int>::iterator cend = C->end(); deque<int>::iterator pit; deque<int>::iterator pstart = (M->front())->begin(); deque<int>::iterator pend = (M->front())->end(); for(cit = cstart, pit = pstart; cit != cend; ++cit, ++pit) { (* cit) -= (* pit); } deque<int> * k = M->front(); M->pop_front(); delete k; h -= R->front(); R->pop_front(); } int row = i + rad; if (row < rows && i > 0) { deque<int> * newQ = new deque<int>(); M->push_back(newQ); deque<int>::iterator cit; deque<int>::iterator cstart = C->begin(); deque<int>::iterator cend = C->end(); int rx; int tot = 0; for (rx = 0, cit = cstart; rx <= rad; rx++, ++cit) { if (rx < cols) { int val = mat[row][rx]; newQ->push_back(val); (* cit) += val; tot += val; } } R->push_back(tot); h += tot; } hh = h; copy(C->begin(), C->end(), Q->begin()); for (j = 1; j < cols; j++) { int col = j + rad; if (j - rad > 0) { hh -= Q->front(); Q->pop_front(); } if (j + rad < cols) { int val = 0; for (int ry =- rad; ry <= rad; ry++) { int y = i + ry; if (y >= 0 && y < rows) { val += mat[y][col]; } } hh += val; Q->push_back(val); } } } } And finally its Java version: public static void opt2Windowing(int [][] mat, int rad){ int cols = mat[0].length; int rows = mat.length; int i = 0; int j = 0; int h = 0; int hh = 0; LinkedList<LinkedList<Integer>> M = new LinkedList<LinkedList<Integer>>(); for (int ry = 0; ry <= rad; ry++) { if (ry < rows) { LinkedList<Integer> q = new LinkedList<Integer>(); M.addLast(q); for (int rx = 0; rx <= rad; rx++) { if (rx < cols) { int val = mat[ry][rx]; q.addLast(val); h += val; } } } } int firstSize = M.getFirst().size(); int mSize = M.size(); LinkedList<Integer> C = new LinkedList<Integer>(); LinkedList<Integer> Q = null; LinkedList<Integer> R = new LinkedList<Integer>(); for (int k = 0; k < firstSize; k++) { C.add(0); } for (int k = 0; k < mSize; k++) { R.add(0); } ListIterator<LinkedList<Integer>> mit; ListIterator<Integer> rit; ListIterator<Integer> cit; ListIterator<Integer> pit; for (mit = M.listIterator(), rit = R.listIterator(); mit.hasNext();) { Integer r = rit.next(); int rsum = 0; for (cit = C.listIterator(), pit = (mit.next()).listIterator(); cit.hasNext();) { Integer c = cit.next(); Integer p = pit.next(); rsum += p; cit.set(c + p); } rit.set(r + rsum); } for (i = 0; i < rows; ++i) { j = 0; if (i - rad > 0) { for(cit = C.listIterator(), pit = M.getFirst().listIterator(); cit.hasNext();) { Integer c = cit.next(); Integer p = pit.next(); cit.set(c - p); } M.removeFirst(); h -= R.getFirst(); R.removeFirst(); } int row = i + rad; if (row < rows && i > 0) { LinkedList<Integer> newQ = new LinkedList<Integer>(); M.addLast(newQ); int rx; int tot = 0; for (rx = 0, cit = C.listIterator(); rx <= rad; rx++) { if (rx < cols) { Integer c = cit.next(); int val = mat[row][rx]; newQ.addLast(val); cit.set(c + val); tot += val; } } R.addLast(tot); h += tot; } hh = h; Q = new LinkedList<Integer>(); Q.addAll(C); for (j = 1; j < cols; j++) { int col = j + rad; if (j - rad > 0) { hh -= Q.getFirst(); Q.pop(); } if (j + rad < cols) { int val = 0; for (int ry =- rad; ry <= rad; ry++) { int y = i + ry; if (y >= 0 && y < rows) { val += mat[y][col]; } } hh += val; Q.addLast(val); } } } } I guess that most is due to the poor choice of the LinkedList in Java and to the lack of an efficient (not shallow) copy method between two LinkedList. How can I improve the third Java method? Am I doing some conceptual error? As always, any criticisms is welcome. UPDATE Even if it does not solve the issue, using ArrayLists, as being suggested, instead of LinkedList improves the third method. The second one performs still better (but when the number of rows and columns of the matrix is lower than 300 and the window radius is small the first unoptimized method is the fastest in Java)

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  • How does one make sure or even guarantee server time are sync correctly between dozens of servers across multiple datacenter on different location?

    - by forestclown
    Currently our web applications contain a logic to check if the data sent to the web server is expired or not by comparing the timestamp of the data with the date/time of the server. Everything goes will, until some dude from data center accidentally modify one of the web server date/time and causes some disruptions in our web services. My managers are of course not happy with this, and said we shouldn't use timestamp to check expiry in the first place...anyway.... Network Time Protocol is implemented, because of data centers are spread across different continents so we have one NTP server in each data center. The servers within the data center will have cron jobs to check against the time with their NTP server from the same data center. If time is out of sync it will auto update the server date/time. But then with our managers not happy with it, and think it could still easily causes the same problem. e.g. what if someone accidentally modify the NTP date/time? what if all the NTP servers are out of sync with each other? which NTP servers we can really trust? and blah blah.. So my questions are: What are the current practice to sync date/time between servers across multiple data centers or locations? How does one manages time stamp between web apps? e.g. Server A send data (contain timestamp of Server A) to Server B (compare timestamp between Server B and the timestamp from the data to see if it has expired or not. This is to avoid HTTP replay) Should we really not use timestamp check? Thanks & Best Regards

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  • WCF net.tcp windows service - call duration and calls outstanding increases over time

    - by Brook
    I have a windows service which uses the ServiceHost class to host a WCF Service using the net.tcp binding. I have done some tweaking to the config to throttle sessions as well as number of connections, but it seems that every once in a while my "Calls outstanding" and "Call duration" shoot up and stay up in perfmon. It seems to me I have a leak somewhere, but the code I have is all fairly minimal, I'm relying on ServiceHost to handle the details. Here's how I start my service ServiceHost host = new ServiceHost(type); host.Faulted+=new EventHandler(Faulted); host.Open(); My Faulted event just does the following (more or less, logging etc removed) if (host.State == CommunicationState.Faulted) { host.Abort(); } else { host.Close(); } host = new ServiceHost(type); host.Faulted+=new EventHandler(Faulted); host.Open(); Here's some snippets from my app.config to show some of the things I've tried <runtime> <gcConcurrent enabled="true" /> <generatePublisherEvidence enabled="false" /> </runtime> ......... <behaviors> <serviceBehaviors> <behavior name="Throttled"> <serviceThrottling maxConcurrentCalls="300" maxConcurrentSessions="300" maxConcurrentInstances="300" /> .......... <services> <service name="MyService" behaviorConfiguration="Throttled"> <endpoint address="net.tcp://localhost:49001/MyService" binding="netTcpBinding" bindingConfiguration="Tcp" contract="IMyService"> </endpoint> </service> </services> .......... <netTcpBinding> <binding name="Tcp" openTimeout="00:00:10" closeTimeout="00:00:10" portSharingEnabled="true" receiveTimeout="00:5:00" sendTimeout="00:5:00" hostNameComparisonMode="WeakWildcard" listenBacklog="1000" maxConnections="1000"> <reliableSession enabled="false"/> <security mode="None"/> </binding> </netTcpBinding> .......... <!--for my diagnostics--> <diagnostics performanceCounters="ServiceOnly" wmiProviderEnabled="true" /> There's obviously some resource getting tied up, but I thought I covered everything with my config. I'm only getting about ~150 clients so I don't think I'm coming up against my "300" limit. "Calls per second" stays constant at anywhere from 2-5 calls per second. The service will run for hours and hours with 0-2 "calls outstanding" and very low "call duration" and then eventually it will shoot up to 30 calls oustanding and 20s call duration. Any tips on what might be causing my "calls outstanding" and "call duration" to spike? Where am I leaking? Point me in the right direction?

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  • WCF: Using Streaming and Username/Password authentication at the same time

    - by Kay
    Hi, I have a WCF Service with the following requirements: a) The client requests a file from the server which is transferred as a Stream. Files may be 100MB or larger. I need streaming or chucking or whatever to make sure that IIS is not loading the whole package into memory before starting to send it. b) The client will transfer an ID to identify the file to be downloaded. The user should be authenticated by providing username/password. c) While the username/password part of the communication needs to be encrypted, encryption of the downloaded file is optional for our use case. My other services, where I am returning smaller files, I am using the following binding: <ws2007HttpBinding> <binding name="ws2007HttpExtern" maxReceivedMessageSize="65536000"> <security mode="Message"> <message clientCredentialType="UserName" /> </security> </binding> </ws2007HttpBinding> But, as I said, that is no good for streaming (Message encryption needs the complete message to encrypt and that is not the case when streaming). So, I asked Microsoft support and I got more or less the following proposal: <bindings> <basicHttpBinding> <binding name="basicStreaming" messageEncoding="Mtom" transferMode="StreamedResponse"> <security mode="Transport"> <transport clientCredentialType="Basic" /> </security> </binding> </bindings> <services> <service behaviorConfiguration="MyProject.WCFInterface.DownloadBehavior" name="MyProject.WCFInterface.DownloadFile"> <endpoint address="" binding="basicHttpBinding" bindingConfiguration="basicStreaming" contract="MyProject.WCFInterface.IDownloadFile" /> <endpoint address="mex" binding="mexHttpBinding" contract="IMetadataExchange" /> </service> </services> <behaviors> <serviceBehaviors> <behavior name="MyProject.WCFInterface.DownloadBehavior"> <serviceMetadata httpGetEnabled="false" httpsGetEnabled="true" /> <serviceDebug includeExceptionDetailInFaults="true" /> </behavior> </serviceBehaviors> </behaviors> When I use this, I get the following error message: Could not find a base address that matches scheme https for the endpoint with binding BasicHttpBinding. Registered base address schemes are [http]. I am using the Web Development Server so far (for production IIS7). I have two questions. a) How would you configure WCF to achieve the goal? b) If the MS proposal is good: What I am doing wrong, the error message does not really help me. Thanks.

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