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ASP.NET MVC vs. ASP.NET 4.0

- by CodeMonkey

I watched this webcast recently, and I got the sense that a lot of the "cool stuff" from ASP.NET MVC is getting pulled back into the ASP.NET framework. At the moment I'm setting the ground-work for a project at my company using ASP.NET MVC, but after watching this, I'm beginning to wonder if that's the right choice, and whether it would behoove me to wait for ASP.NET 4.0. I realize ASP.NET MVC 2.0 is getting close to an actual release. If High-Testability, loose coupling, and having Full control of our HTML are top priorities, which should I choose, ASP.NET 4.0 or ASP.NET MVC?

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Memory Allocation Profiling in C++

- by Amit Kumar

I am writing an application and am surprised to see its total memory usage is already too high. I want to profile the dynamic memory usage of my application: How many objects of each kind are there in the heap, and which functions created these objects? Also, how much memory is used by each of the object? Is there a simple way to do this? I am working on both linux and windows, so tools of any of the platforms would suffice. NOTE: I am not concerned with memory leaks here.

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How to add a view on top of a UIPopoverController

- by Noah Witherspoon

I've got an iPad app with a “drawer” table displayed in a popover. The user can tap-and-hold on an item in the drawer to drag that item out of it and into my main view. That part works fine; unfortunately, the view being dragged appears under the popover, and is too small to be visible until it's dragged out from underneath it. If I add the view as a subview of the view controller in the popover, it gets clipped by the popover's frame, and as I can't access the UIPopoverController's view, I can't disable its layer's masksToBounds—and that probably wouldn't be a great idea anyway. I suspect that I could use an additional UIWindow with a high windowLevel value to force the dragged view to appear on top of the popover, but this seems like overkill. Is there a better solution?

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Shopping Portal based on XML Data - XSLT or PHP?

- by buggy1985

For my bachelor thesis I want to implement a shopping (price comparison) portal prototype based on XML Data. The main requirement is to get a very clear and customizable HTML template, which should be hosted by the customer on his own webserver. I'm not very sure if XSLT meets this requirements, as it generates a lot of xsl-related code. It is not easy to understand for people with little HTML skills. I have some experience with the PHP templating engine Smarty. The syntax is much better, but I'm not sure if it's a good idea to parse the XML data with PHP, as it is very complex. Which language should I choose for a web application with high complexity? XSLT or PHP?

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Multi page forms on ASP.NET MVC

- by Jay

Hi, I have decided to use ASP.NET MVC to develop multi page (registration) forms in asp.net. There will be two buttons on each page that allows the user to navigate to the previous and next page. When the user navigates back to a page they recently filled out, the data should be displayed to them. I understand ASP.NET MVC should remain stateless but how should I maintain page information when the user navigates back and forth. Should I? Save the information to a database and retrieve information for each page change? save information to the session? Load all the fields and display only whats's needed with javascript? This registration form is going to be used in multiple sites but with different sets of questions (Some may be the same). IF performance is a main concern, should I avoid generating these forms dynamically? Jay

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Is there a log file analyzer for log4j files?

- by Juha Syrjälä

I am looking for some kind of analyzer tool for log files generated by log4j files. I am looking something more advanced than grep? What are you using for log file analysis? I am looking for following kinds of features: The tool should tell me how many time a given log statement or a stack trace has occurred, preferably with support for some kinds of patterns (eg. number of log statements matching 'User [a-z]* logged in'). Breakdowns by log level (how many INFO, DEBUG lines) and by class that initiated the log message would be nice. Breakdown by date (how many log statements in given time period) What log lines occur commonly together? Support for several files since I am using log rolling Hot spot analysis: find if there is a some time period when there is unusually high number of log statements Either command-line or GUI are fine Open Source is preferred but I am also interested in commercial offerings My log4j configuration uses org.apache.log4j.PatternLayout with pattern %d %p %c - %m%n but that could be adapted for analyzer tool.

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Service broker with SqlNotificationRequest

- by user171523

I am in the process of evaluating a Service Broker with SQL noticiation for my project. My requirements is User places a order from System A and it will update Order Table. As soon as order is place i need to notify the System B. I have done a quick POC with Trigger , Service Broker and SQLNotificaiton ADO.NET. It is working as i expected. What i would like to know the group A) What are the best practices i need to follow for this? B) What are disadvantages with the above approach if any? C) Are there any disadvantes of using the Triggers? If so what are those for above approach? The order table will get order from System A like 1000 to 1500 every day. I also would like to know the performance of above approach.

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Python imaging alternatives

- by Paul McMillan

I have python code that needs to do just a couple simple things to photographs: crop, resize, and overlay a watermark. I've used PIL, and the resample/resize results are TERRIBLE. I've used imagemagick, and the interface and commands were designed by packaging a cat in a box, and then repeatedly throwing it down a set of stairs at a keyboard. I'm looking for something which is not PIL or Imagemagick that I can use with python to do simple, high-quality image transformations. For that matter, it doesn't even have to have python bindings if the command line interface is good. Oh, and it needs to be relatively platform agnostic, our production servers are linux, but some of our devs develop on windows. It can't require the installation of a bunch of silly gui code to use as a library, either.

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Why shouldn't I always use nullable types in C#.

- by Matthew Vines

I've been searching for some good guidance on this since the concept was introduced in .net 2.0. Why would I ever want to use non-nullable data types in c#? (A better question is why wouldn't I choose nullable types by default, and only use non-nullable types when that explicitly makes sense.) Is there a 'significant' performance hit to choosing a nullable data type over its non-nullable peer? I much prefer to check my values against null instead of Guid.empty, string.empty, DateTime.MinValue,<= 0, etc, and to work with nullable types in general. And the only reason I don't choose nullable types more often is the itchy feeling in the back of my head that makes me feel like it's more than backwards compatibility that forces that extra '?' character to explicitly allow a null value. Is there anybody out there that always (most always) chooses nullable types rather than non-nullable types? Thanks for your time,

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MVVM Good Design. DataSet or a RowViewModel

- by LnDCobra

I have just started learning MVVM and having a dilemna. If I have a a main ViewModel and inside this model I have a number of datasets. Now should I be creating a new ViewModel for each row inside the dataset? Or expose the DataSet itself as a DependencyProperty? For now the dataset has about 20 rows inside it, and the thought of iterating through each row to create a ViewModel binding to each row.... might not be the best option for performance reasons and memory reasons in the future, like when there are 1000+ rows. Should I still go ahead and create a RowViewModel and iterate through the dataset? And have an ObservableCollection of it or just expose the dataset? Any help would be greatly appreciated.

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com.sun.management.OperatingSystemMXBean use in an OSGi bundle

- by Paul Whelan

I have some legacy code that was used to monitor my applications cpu,memory etc that I want to convert to a bundle. Now when i start this bundle its complaining Missing Constraint: Import-Package: com.sun.management; version="0.0.0" I had used the OperatingSystemMXBean to get access to stats on the JVM. My question is can I use this class inside an OSGI container and if so how? Or should I use some other way to monitor my application. I was making an RMI call to the application from a web frontend to get the nodes performance figures pre OSGi.

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SElinux process killed while trying to set boolean

- by Antonio

I've got a strange problem. I can not allow apache to connect to database at my CentOC 6.4 box: [root@centos6 ~]# setsebool -P httpd_can_network_connect on Killed [root@centos6 ~]# sestatus -b | grep httpd_can_network_connect httpd_can_network_connect off httpd_can_network_connect_cobbler off httpd_can_network_connect_db off I watched log file, but there was no log messages: tail -f /var/log/audit/audit.log UPDATE: There are some information in /var/log/messages: Nov 9 19:07:16 vs302 kernel: setsebool invoked oom-killer: gfp_mask=0x280da, order=0, oom_adj=0, oom_score_adj=0 Nov 9 19:07:16 vs302 kernel: setsebool cpuset=/ mems_allowed=0 Nov 9 19:07:16 vs302 kernel: Pid: 1660, comm: setsebool Not tainted 2.6.32-358.23.2.el6.x86_64 #1 Nov 9 19:07:16 vs302 kernel: Call Trace: Nov 9 19:07:16 vs302 kernel: [<ffffffff810cb641>] ? cpuset_print_task_mems_allowed+0x91/0xb0 Nov 9 19:07:16 vs302 kernel: [<ffffffff8111ce40>] ? dump_header+0x90/0x1b0 Nov 9 19:07:16 vs302 kernel: [<ffffffff8111d2c2>] ? oom_kill_process+0x82/0x2a0 Nov 9 19:07:16 vs302 kernel: [<ffffffff8111d201>] ? select_bad_process+0xe1/0x120 Nov 9 19:07:16 vs302 kernel: [<ffffffff8111d700>] ? out_of_memory+0x220/0x3c0 Nov 9 19:07:16 vs302 kernel: [<ffffffff8112c3dc>] ? __alloc_pages_nodemask+0x8ac/0x8d0 Nov 9 19:07:16 vs302 kernel: [<ffffffff81160d6a>] ? alloc_pages_vma+0x9a/0x150 Nov 9 19:07:16 vs302 kernel: [<ffffffff81143f0b>] ? handle_pte_fault+0x76b/0xb50 Nov 9 19:07:16 vs302 kernel: [<ffffffff81228664>] ? task_has_capability+0xb4/0x110 Nov 9 19:07:16 vs302 kernel: [<ffffffff81004a49>] ? __raw_callee_save_xen_pmd_val+0x11/0x1e Nov 9 19:07:16 vs302 kernel: [<ffffffff8114452a>] ? handle_mm_fault+0x23a/0x310 Nov 9 19:07:16 vs302 kernel: [<ffffffff811485b6>] ? vma_adjust+0x556/0x5e0 Nov 9 19:07:16 vs302 kernel: [<ffffffff810474e9>] ? __do_page_fault+0x139/0x480 Nov 9 19:07:16 vs302 kernel: [<ffffffff81148b8a>] ? vma_merge+0x29a/0x3e0 Nov 9 19:07:16 vs302 kernel: [<ffffffff81149fdc>] ? do_brk+0x26c/0x350 Nov 9 19:07:16 vs302 kernel: [<ffffffff8100ba1d>] ? retint_restore_args+0x5/0x6 Nov 9 19:07:16 vs302 kernel: [<ffffffff81513bfe>] ? do_page_fault+0x3e/0xa0 Nov 9 19:07:16 vs302 kernel: [<ffffffff81510fb5>] ? page_fault+0x25/0x30 Nov 9 19:07:16 vs302 kernel: Mem-Info: Nov 9 19:07:16 vs302 kernel: Node 0 DMA per-cpu: Nov 9 19:07:16 vs302 kernel: CPU 0: hi: 0, btch: 1 usd: 0 Nov 9 19:07:16 vs302 kernel: Node 0 DMA32 per-cpu: Nov 9 19:07:16 vs302 kernel: CPU 0: hi: 186, btch: 31 usd: 30 Nov 9 19:07:16 vs302 kernel: active_anon:132249 inactive_anon:46 isolated_anon:0 Nov 9 19:07:16 vs302 kernel: active_file:56 inactive_file:59 isolated_file:0 Nov 9 19:07:16 vs302 kernel: unevictable:0 dirty:2 writeback:0 unstable:0 Nov 9 19:07:16 vs302 kernel: free:1369 slab_reclaimable:1774 slab_unreclaimable:11588 Nov 9 19:07:16 vs302 kernel: mapped:54 shmem:48 pagetables:1211 bounce:0 Nov 9 19:07:16 vs302 kernel: Node 0 DMA free:2440kB min:72kB low:88kB high:108kB active_anon:12156kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:14648kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:24kB slab_unreclaimable:8kB kernel_stack:0kB pagetables:16kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes Nov 9 19:07:16 vs302 kernel: lowmem_reserve[]: 0 590 590 590 Nov 9 19:07:16 vs302 kernel: Node 0 DMA32 free:3036kB min:3072kB low:3840kB high:4608kB active_anon:516840kB inactive_anon:184kB active_file:224kB inactive_file:236kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:604988kB mlocked:0kB dirty:8kB writeback:0kB mapped:216kB shmem:192kB slab_reclaimable:7072kB slab_unreclaimable:46344kB kernel_stack:880kB pagetables:4828kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:128 all_unreclaimable? no Nov 9 19:07:16 vs302 kernel: lowmem_reserve[]: 0 0 0 0 Nov 9 19:07:16 vs302 kernel: Node 0 DMA: 0*4kB 1*8kB 0*16kB 0*32kB 0*64kB 1*128kB 1*256kB 0*512kB 0*1024kB 1*2048kB 0*4096kB = 2440kB Nov 9 19:07:16 vs302 kernel: Node 0 DMA32: 129*4kB 67*8kB 30*16kB 19*32kB 6*64kB 2*128kB 1*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 3036kB Nov 9 19:07:16 vs302 kernel: 182 total pagecache pages Nov 9 19:07:16 vs302 kernel: 0 pages in swap cache Nov 9 19:07:16 vs302 kernel: Swap cache stats: add 0, delete 0, find 0/0 Nov 9 19:07:16 vs302 kernel: Free swap = 0kB Nov 9 19:07:16 vs302 kernel: Total swap = 0kB Nov 9 19:07:16 vs302 kernel: 157439 pages RAM Nov 9 19:07:16 vs302 kernel: 6271 pages reserved Nov 9 19:07:16 vs302 kernel: 2686 pages shared Nov 9 19:07:16 vs302 kernel: 146395 pages non-shared Nov 9 19:07:16 vs302 kernel: [ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name Nov 9 19:07:16 vs302 kernel: [ 271] 0 271 2798 231 0 -17 -1000 udevd Nov 9 19:07:16 vs302 kernel: [ 476] 0 476 2797 230 0 -17 -1000 udevd Nov 9 19:07:16 vs302 kernel: [ 718] 0 718 2279 122 0 0 0 dhclient Nov 9 19:07:16 vs302 kernel: [ 762] 0 762 6909 58 0 -17 -1000 auditd Nov 9 19:07:16 vs302 kernel: [ 787] 0 787 62270 147 0 0 0 rsyslogd Nov 9 19:07:16 vs302 kernel: [ 801] 25 801 40326 2655 0 0 0 named Nov 9 19:07:16 vs302 kernel: [ 850] 0 850 16563 172 0 -17 -1000 sshd Nov 9 19:07:16 vs302 kernel: [ 875] 0 875 23451 240 0 0 0 sshd Nov 9 19:07:16 vs302 kernel: [ 966] 498 966 4780 44 0 0 0 wrapper Nov 9 19:07:16 vs302 kernel: [ 968] 498 968 497404 40812 0 0 0 java Nov 9 19:07:16 vs302 kernel: [ 1057] 0 1057 20216 225 0 0 0 master Nov 9 19:07:16 vs302 kernel: [ 1064] 89 1064 20278 209 0 0 0 qmgr Nov 9 19:07:16 vs302 kernel: [ 1071] 0 1071 27075 121 0 0 0 bash Nov 9 19:07:16 vs302 kernel: [ 1111] 0 1111 24880 350 0 0 0 httpd Nov 9 19:07:16 vs302 kernel: [ 1117] 48 1117 24913 351 0 0 0 httpd Nov 9 19:07:16 vs302 kernel: [ 1118] 48 1118 24880 337 0 0 0 httpd Nov 9 19:07:16 vs302 kernel: [ 1119] 48 1119 24880 337 0 0 0 httpd Nov 9 19:07:16 vs302 kernel: [ 1120] 48 1120 24880 337 0 0 0 httpd Nov 9 19:07:16 vs302 kernel: [ 1121] 48 1121 24880 337 0 0 0 httpd Nov 9 19:07:16 vs302 kernel: [ 1122] 48 1122 24880 337 0 0 0 httpd Nov 9 19:07:16 vs302 kernel: [ 1124] 48 1124 24880 337 0 0 0 httpd Nov 9 19:07:16 vs302 kernel: [ 1125] 48 1125 24880 337 0 0 0 httpd Nov 9 19:07:16 vs302 kernel: [ 1129] 0 1129 29313 151 0 0 0 crond Nov 9 19:07:16 vs302 kernel: [ 1143] 0 1143 1018 22 0 0 0 agetty Nov 9 19:07:16 vs302 kernel: [ 1146] 0 1146 1015 22 0 0 0 mingetty Nov 9 19:07:16 vs302 kernel: [ 1514] 0 1514 23451 237 0 0 0 sshd Nov 9 19:07:16 vs302 kernel: [ 1517] 0 1517 27075 113 0 0 0 bash Nov 9 19:07:16 vs302 kernel: [ 1641] 89 1641 20236 218 0 0 0 pickup Nov 9 19:07:16 vs302 kernel: [ 1659] 0 1659 25234 39 0 0 0 tail Nov 9 19:07:16 vs302 kernel: [ 1660] 0 1660 89903 85712 0 0 0 setsebool Nov 9 19:07:16 vs302 kernel: Out of memory: Kill process 1660 (setsebool) score 568 or sacrifice child Nov 9 19:07:16 vs302 kernel: Killed process 1660, UID 0, (setsebool) total-vm:359612kB, anon-rss:342708kB, file-rss:140kB

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F# currying efficiency?

- by Eamon Nerbonne

I have a function that looks as follows: let isInSet setElems normalize p = normalize p |> (Set.ofList setElems).Contains This function can be used to quickly check whether an element is semantically part of some set; for example, to check if a file path belongs to an html file: let getLowerExtension p = (Path.GetExtension p).ToLowerInvariant() let isHtmlPath = isInSet [".htm"; ".html"; ".xhtml"] getLowerExtension However, when I use a function such as the above, performance is poor since evaluation of the function body as written in "isInSet" seems to be delayed until all parameters are known - in particular, invariant bits such as (Set.ofList setElems).Contains are reevaluated each execution of isHtmlPath. How can best I maintain F#'s succint, readable nature while still getting the more efficient behavior in which the set construction is preevaluated. The above is just an example; I'm looking for a general pattern that avoids bogging me down in implementation details - where possible I'd like to avoid being distracted by details such as the implementation's execution order since that's usually not important to me and kind of undermines a major selling point of functional programming.

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Nice name for `decorator' class?

- by Lajos Nagy

I would like to separate the API I'm working on into two sections: 'bare-bones' and 'cushy'. The idea is that all method calls in the 'cushy' section could be expressed in terms of the ones in the 'bare-bones' section, that is, they would only serve as convenience methods for the quick-and-dirty. The reason I would like to do this is that very often when people are beginning to use an API for the first time, they are not interested in details and performance: they just want to get it working. Anybody tried anything similar before? I'm particularly interested in naming conventions and organizing the code.

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Rails Associations Question

- by Mutuelinvestor

I'm new to rails and have volunteered to help out the local High School Track team with a simple database that tracks the runners performances. For the moment, I have three models: Runners, Race_Data and Races. I have the following associations. Runners have_many Race_Data Races have_many Race_Data I also want create the association Runners Have_Many Races Through Race_Data, but as my look at the diagram I have drawn, there is already a many to one relationship from Race_data to Races. Does the combination of Runners having many Race_Data and Race_Data having one Race imply a Many_to_Many relationship between Runners and Races?

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SQL Server, temporary tables with truncate vs table variable with delete

- by Richard

I have a stored procedure inside which I create a temporary table that typically contains between 1 and 10 rows. This table is truncated and filled many times during the stored procedure. It is truncated as this is faster than delete. Do I get any performance increase by replacing this temporary table with a table variable when I suffer a penalty for using delete (truncate does not work on table variables) Whilst table variables are mainly in memory and are generally faster than temp tables do I loose any benefit by having to delete rather than truncate?

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Java Concurrency: CAS vs Locking

- by Hugo Walker

Im currently reading the Book Java Concurrency in Practice. In the Chapter 15 they are speaking about the Nonblocking algorithms and the compare-and-swap (CAS) Method. It is written that the CAS perform much better than the Locking Methods. I want to ask the people which already worked with both of this concepts and would like to hear when you are preferring which of these concept? Is it really so much faster? Personally for me the usage of Locks is much clearer and easier to understand and maybe even better to maintain. (Please correct me if I am wrong). Should we really focus creating our concurrent code related on CAS than Locks to get a better performance boost or is sustainability a higher thing? I know there is maybe not a strict rule, when to use what. But I just would like to hear some opinions, experiences with the new concept of CAS.

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Language/tech specific books which improve vendor-neutral development skills

- by dotnetdev

If I ask what the following books have in common: "Accelerated C# 2010, C# in Depth, Pro C# 2008", the answer would be that they would help me to improve my understanding of C# and secondly, my general coding skills. What language-specific/tech-specific books (like those named above) would teach me a great deal about general programming techniques and good habits? I'm thinking Java books would be very good for me (I code in C# primarily), as both these languages are similar and so I am sure that specialist books on Java threading, performance tuning, etc, can be applied to C# (not all 100% content of a Java book). Thanks

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NameValueCollection vs Dictionary<string,string>

- by frankadelic

Any reason I should use Dictionary<string,string instead of NameValueCollection? (in C# / .NET Framework) Option 1, using NameValueCollection: //enter values: NameValueCollection nvc = new NameValueCollection() { {"key1", "value1"}, {"key2", "value2"}, {"key3", "value3"} }; // retrieve values: foreach(string key in nvc.AllKeys) { string value = nvc[key]; // do something } Option 2, using Dictionary<string,string... //enter values: Dictionary<string, string> dict = new Dictionary<string, string>() { {"key1", "value1"}, {"key2", "value2"}, {"key3", "value3"} }; // retrieve values: foreach (KeyValuePair<string, string> kvp in dict) { string key = kvp.Key; string val = kvp.Value; // do something } For these use cases, is there any advantage to use one versus the other? Any difference in performance, memory use, sort order, etc.?

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Distributing APNS providers

- by Sam

I'm writing a business-focused iPhone app which includes a self-hosted server component. I'd like to include push notification functionality in the server; reading through the programming guide it looks as if this would involve either: Distributing the provider certificate with the server component - this doesn't sound like a terribly good idea (even if Apple permits it?) Hosting a shared notification provider and forwarding notifications to APNS from the servers. For an ongoing, high-availability service, this is likely to require including a subscription pricing component, which I would prefer to avoid. Require customers to apply for their own provider certificate. However, it's not clear whether multiple organisations are allowed to apply for provider certificates with a single bundle ID, and it would significantly increase the barrier to adoption. APNS looks to me as if it's specifically geared for centrally hosted services. Is anyone distributing self-hosted notification providers? Are there any other options?

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Can I do video communication with silverlight 4.0?

- by tom greene

With silverlight 4.0, it is possible to show a live video of the user on the screen: Here is the code VideoBrush videoBrush = new VideoBrush(); CaptureSource captureSource = new CaptureSource { VideoCaptureDevice = CaptureDeviceConfiguration.GetAvailableVideoCaptureDevices().First() }; bool b = CaptureDeviceConfiguration.RequestDeviceAccess(); videoBrush.SetSource(captureSource); captureSource.Start(); myrect.Fill = videoBrush; However, I am looking at a way to show the video to someone else - seeing oneself on screen is not that interesting. Is it possible? Do I need my own server? Can I use clowd services to do the communication? Are there performance issues?

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PyPy -- How can it possible beat CPython?

- by Vulcan Eager

From the Google Open Source Blog: PyPy is a reimplementation of Python in Python, using advanced techniques to try to attain better performance than CPython. Many years of hard work have finally paid off. Our speed results often beat CPython, ranging from being slightly slower, to speedups of up to 2x on real application code, to speedups of up to 10x on small benchmarks. How is this possible? Which Python implementation was used to implement PyPy? CPython? And what are the chances of a PyPyPy or PyPyPyPy beating their score? (On a related note... why would anyone try something like this?)

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Is there any killer application for Ontology/semantics/OWL/RDF yet?

- by narnirajesh

Hi Guys, I got interested in semantic technologies after reading a lot of books, blogs and articles on the net saying that it would make data machine-understandable, allow intelligent agents make great reasoning, automated & dynamic service composition etc.. I am still reading the same stuff from 2 years. The number of articles/blogs/semantic-conferences have increased considerably. But I am still unable to see any killer-application. Why is it so? Or is there some application/product (commercial/open-source) already existing, which actually is doing all that being boasted of? To put it more precisely, is there any product that leverages semantic technologies (esp RDF/OWL/SPARQL) and is delivering functionality/performance/maintainability, which would not have been possible with the existing (no-semantic) technologies? Some product that is completely dependent on semantic technologies and really adds value to the customers and generating revenues?

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Handler invocation speed: Objective-C vs virtual functions

- by Kerido

I heard that calling a handler (delegate, etc.) in Objective-C can be even faster than calling a virtual function in C++. Is it really correct? If so, how can that be? AFAIK, virtual functions are not that slow to call. At least, this is my understanding of what happens when a virtual function is called: Compute the index of the function pointer location in vtbl. Obtain the pointer to vtbl. Dereference the pointer and obtain the beginning of the array of function pointers. Offset (in pointer scale) the beginning of the array with the index value obtained on step 1. Issue a call instruction. Unfortunately, I don't know Objective-C so it's hard for me to compare performance. But at least, the mechanism of a virtual function call doesn't look that slow, right? How can something other than static function call be faster?

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Concatenate boost::dynamic_bitset or std::bitset

- by MOnsDaR

Hey, what is the best way to concatenate 2 bitsets? For example i've got boost::dynamic_bitset<> test1( std::string("1111") ); boost::dynamic_bitset<> test2( std::string("00") ); they should be concatenated into a thrid Bitset test3 which then holds 111100 Solutions should use boost::dynamic_bitset. If the solution works with std::bitset, it would be nice too. There should be a focus on performance when concatenating the bits.

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