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  • When do I use Apache Kafka, Azure Service Bus, vs Azure Queues?

    - by makerofthings7
    I'm trying to understand the situations I'd use Apache Kafka, Azure Service Bus, or Azure Queues for high scale message processing. Which is better for standard Pub Sub situations? Where multiple clients get a copy of the same message? Which is better for low latency Pub sub and no durability? Which is better for "cooperating producer" and "competing consumer"? (what does this mean?) I see a bit of overlap in function between Kafka, Service Bus, Azure Queues

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  • Oracle Releases New Mainframe Re-Hosting in Oracle Tuxedo 11g

    - by Jason Williamson
    I'm excited to say that we've released our next generation of Re-hosting in 11g. In fact I'm doing some hands-on labs now for our Systems Integrators in Italy in a couple of weeks and targeting Latin America next month. If you are an SI, or Rehosting firm and are looking to become an Oracle Partner or get a better understanding of Tuxedo and how to use the workbench for rehosting...drop me a line. Oracle Tuxedo Application Runtime for CICS and Batch 11g provides a CICS API emulation and Batch environment that exploits the full range of Oracle Tuxedo's capabilities. Re-hosted applications run in a multi-node, grid environment with centralized production control. Also, enterprise integration of CICS application services benefits from an open and SOA-enabled framework. Key features include: CICS Application Runtime: Can run IBM CICS applications unchanged in an application grid, which enables the distribution of large workloads across multiple processors and nodes. This simplifies CICS administration and can scale to over 100,000 users and over 50,000 transactions per second. 3270 Terminal Server: Protects business users from change through support for tn3270 terminal emulation. Distributed CICS Resource Management: Simplifies deployment and administration by allowing customers to run CICS regions in a distributed configuration. Batch Application Runtime: Provides robust IBM JES-like job management that enables local or remote job submissions. In addition, distributed batch initiators can enable parallelization of jobs and support fail-over, shortening the batch window and helping to meet stringent SLAs. Batch Execution Environment: Helps to run IBM batch unchanged and also supports JCL functionality and all common batch utilities. Oracle Tuxedo Application Rehosting Workbench 11g provides a set of automated migration tools integrated around a central repository. The tools provide high precision which results in very low error rates and the ability to handle large applications. This enables less expensive, low-risk migration projects. Key capabilities include: Workbench Repository and Cataloguer: Ensures integrity of the migrated application assets through full dependency checking. The Cataloguer generates and maintains all relevant meta-data on source and target components. File Migrator: Supports reliable migration of datasets and flat files to an ISAM or Oracle Database 11g. This is done through the automated migration utilities for data unloading, reloading and validation. It also generates logical access functions to shield developers from data repository changes. DB2 Migrator: Similarly, this tool automates the migration of DB2 schema and data to Oracle Database 11g. COBOL Migrator: Supports migration of IBM mainframe COBOL assets (OLTP and Batch) to open systems. Adapts programs for compiler dialects and data access variations. JCL Migrator: Supports migration of IBM JCL jobs to a Tuxedo ART environment, maintaining the flow and characteristics of batch jobs.

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  • 10.10 freezing when sftp downloading

    - by aGr
    My ubuntu 10.10 is freezing during downloading from my other computer on sftp. I thought it might be some nautilus issues so I tried it via command line and I got the same thing - after few minutes the whole computer freezes. Mostly the numlock led is blinking (I've heard somewhere that this means a kernel panic), but not in 100% cases. I dunno if that helps but here is a log from /var/log/message in the time that this happened. At least I hope so - it wasn't that big, when it happened before. But this looks quite "errorish", right? (isn't complete - see bottom) Jan 5 17:57:49 tomas-ntb kernel: imklog 4.2.0, log source = /proc/kmsg started. Jan 5 17:57:49 tomas-ntb rsyslogd: [origin software="rsyslogd" swVersion="4.2.0" x-pid="953" x-info="http://www.rsyslog.com"] (re)start Jan 5 17:57:49 tomas-ntb rsyslogd: rsyslogd's groupid changed to 103 Jan 5 17:57:49 tomas-ntb rsyslogd: rsyslogd's userid changed to 101 Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] Initializing cgroup subsys cpuset Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] Initializing cgroup subsys cpu Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] Linux version 2.6.35-24-generic (buildd@vernadsky) (gcc version 4.4.5 (Ubuntu/Linaro 4.4.4-14ubuntu5) ) #42-Ubuntu SMP Thu Dec 2 01:41:57 UTC 2010 (Ubuntu 2.6.35-24.42-generic 2.6.35.8) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-provided physical RAM map: Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 0000000000000000 - 000000000009e800 (usable) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 000000000009e800 - 00000000000a0000 (reserved) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 00000000000e0000 - 0000000000100000 (reserved) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 0000000000100000 - 00000000dffa8000 (usable) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 00000000dffa8000 - 00000000dffb0000 (ACPI NVS) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 00000000dffb0000 - 00000000dffbff00 (ACPI data) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 00000000dffbff00 - 00000000dfff0000 (ACPI NVS) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 00000000dfff0000 - 00000000e0000000 (reserved) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 00000000fec00000 - 00000000fec01000 (reserved) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 00000000fee00000 - 00000000fee01000 (reserved) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 00000000ff700000 - 0000000100000000 (reserved) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 0000000100000000 - 0000000120000000 (usable) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] BIOS-e820: 0000000120000000 - 0000000140000000 (reserved) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] Notice: NX (Execute Disable) protection cannot be enabled: non-PAE kernel! Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] DMI 2.5 present. Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] AMI BIOS detected: BIOS may corrupt low RAM, working around it. Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] last_pfn = 0xdffa8 max_arch_pfn = 0x100000 Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] x86 PAT enabled: cpu 0, old 0x7040600070406, new 0x7010600070106 Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] Scanning 0 areas for low memory corruption Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] modified physical RAM map: Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] modified: 0000000000000000 - 0000000000010000 (reserved) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] modified: 0000000000010000 - 000000000009e800 (usable) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] modified: 000000000009e800 - 00000000000a0000 (reserved) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] modified: 00000000000e0000 - 0000000000100000 (reserved) Jan 5 17:57:49 tomas-ntb kernel: [ 0.000000] modified: 0000000000100000 - 00000000dffa8000 (usable) ... to long - for whole and better view click here

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  • Service Broker Solutions - Don't Forget the Basics

    - by AllenMWhite
    After finally getting a Service Broker solution implemented successfully, I'm really impressed with the technology, and frustrated how difficult it can be to implement and get it really working as expected. First, understand the technology. There are some great resources out there to help you get started. The first place to go is Klaus Aschenbrenner's book, the one that Greg Low reviewed this past week. It's an amazing resource and played a large part in my success. (I bought it for my Kindle, and...(read more)

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  • XNA Per-Polygon Collision Check

    - by user22985
    I'm working on a project in XNA for WP7 with a low-poly environment, my problem is I need to setup a working per-polygon collision check between 2 or more 3d meshes. I've checked tons of tutorials but all of them use bounding-boxes, bounding-spheres,rays etc., but what I really need is a VERY precise way of checking if the polygons of two distinct models have intersected or not. If you could redirect me to an example or at least give me some pointers I would be grateful.

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  • Compute Scalars, Expressions and Execution Plan Performance

    - by Paul White
    The humble Compute Scalar is one of the least well-understood of the execution plan operators, and usually the last place people look for query performance problems. It often appears in execution plans with a very low (or even zero) cost, which goes some way to explaining why people ignore it. Some readers will already know that a Compute Scalar can contain a call to a user-defined function, and that any T-SQL function with a BEGIN…END block in its definition can have truly disastrous consequences...(read more)

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  • Problem in installation in My Hp g4 1226se

    - by vivek Verma
    1vivek.100 Dual booting error in Hp pavilion g4 1226se Dear sir or Madam, My name is vivek verma.... I am the user of my Hp laptop which series and model name is HP PAVILION G4 1226SE........ i have purchase in the year of 2012 and month is February.....the windows 7 home basic 64 Bit is already installed in in my laptop.... Now i want to install Ubuntu 12.04 Lts or 13.10 lts..... i have try many time to install in my laptop via live CD or USB installer....and i have try many live CD and many pen drive to install Ubuntu ... but it is not done......now i am in very big problem...... when i put my CD or USB drive to boot and install the Ubuntu......my laptop screen is goes the some black (brightness of my laptop screen is very low and there is very low visibility ) and not showing any thing on my laptop screen..... and when i move the my laptop screen.....then there is graphics option in this screen to installation of the Ubuntu option......and when i press the dual boot with setting button and press to continue them my laptop is goes for shutdown after 2 or 5 minutes..... ...... and Hp service center person is saying to me our laptop hardware has no problem.....please contact to Ubuntu tech support............. show please help me if possible..... My laptop configuration is here...... Hardware Product Name g4-1226se Product Number QJ551EA Microprocessor 2.4 GHz Intel Core i5-2430M Microprocessor Cache 3 MB L3 cache Memory 4 GB DDR3 Memory Max Upgradeable to 4 GB DDR3 Video Graphics Intel HD 3000 (up to 1.65 GB) Display 35,5 cm (14,0") High-Definition LED-backlit BrightView Display (1366 x 768) Hard Drive 500 GB SATA (5400 rpm) Multimedia Drive SuperMulti DVD±R/RW with Double Layer Support Network Card Integrated 10/100 BASE-T Ethernet LAN Wireless Connectivity 802.11 b/g/n Sound Altec Lansing speakers Keyboard Full size island-style keyboard with home roll keys Pointing Device TouchPad supporting Multi-Touch gestures with On/Off button PC Card Slots Multi-Format Digital Media Card Reader for Secure Digital cards, Multimedia cards External Ports 1 VGA 1 headphone-out 1 microphone-in 3 USB 2.0 1 RJ45 Dimensions 34.1 x 23.1 x 3.56 cm Weight Starting at 2.1 kg Power 65W AC Power Adapter 6-cell Lithium-Ion (Li-Ion) What's In The Box Webcam with Integrated Digital Microphone (VGA) Software Operating System: Windows 7 Home Basic 64bit....Genuine..... ......... Sir please help me if possible....... Name =vivek verma Contact no.+919911146737 Email [email protected]

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  • A list of game mechanics

    - by Iain
    I'm trying to compile a list of game mechanics, by which I mean high-level/meta game mechanics like Cooperation, Resource Management, Chance and Time Manipulation rather than low level mechanics like running, jumping climbing ladders, etc Does any one have any suggestions or can point me to good existing lists? My WIP list is already proving to be quite useful to me in the way I think about games.

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  • Only a few places left for the SQL Social evening on 16th March

    - by simonsabin
    We've got over 50 people registered for the SQLSocial event on 16th March with Itzik Ben-Gan, Greg Low, Davide Mauri and Bill Vaughn I need to finalise numbers on early next week so if you want to come along please register asap, otherwise I can't promise that we'll have space for you. To register use he form on herehttp://sqlsocial.com/events.aspx. I look forward to hearing from you.

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  • Ghost team foundation build controllers

    - by Martin Hinshelwood
    Quite often after an upgrade there are things left over. Most of the time they are easy to delete, but sometimes it takes a little effort. Even rarer are those times when something just will not go away no matter how much you try. We have had a ghost team build controller hanging around for a while now, and it had defeated my best efforts to get rid of it. The build controller was from our old TFS server from before our TFS 2010 beta 2 upgrade and was really starting to annoy me. Every time I try to delete it I get the message: Controller cannot be deleted because there are build in progress -Manage Build Controller dialog   Figure: Deleting a ghost controller does not always work. I ended up checking all of our 172 Team Projects for the build that was queued, but did not find anything. Jim Lamb pointed me to the “tbl_BuildQueue” table in the team Project Collection database and sure enough there was the nasty little beggar. Figure: The ghost build was easily spotted Adam Cogan asked me: “Why did you suspect this one?” Well, there are a number of things that led me to suspect it: QueueId is very low: Look at the other items, they are in the thousands not single digits ControllerId: I know there is only one legitimate controller, and I am assuming that 6 relates to “zzUnicorn” DefinitionId: This is a very low number and I looked it up in “tbl_BuildDefinition” and it did not exist QueueTime: As we did not upgrade to TFS 2010 until late 2009 a date of 2008 for a queued build is very suspect Status: A status of 2 means that it is still queued This build must have been queued long ago when we were using TFS 2008, probably a beta, and it never got cleaned up. As controllers are new in TFS 2010 it would have created the “zzUnicorn” controller to handle any build servers that already exist. I had previously deleted the Agent, but leaving the controller just looks untidy. Now that the ghost build has been identified there are two options: Delete the row I would not recommend ever deleting anything from the database to achieve something in TFS. It is really not supported. Set the Status to cancelled (Recommended) This is the best option as TFS will then clean it up itself So I set the Status of this build to 2 (cancelled) and sure enough it disappeared after a couple of minutes and I was then able to then delete the “zzUnicorn” controller. Figure: Almost completely clean Now all I have to do is get rid of that untidy “zzBunyip” agent, but that will require rewriting one of our build scripts which will have to wait for now.   Technorati Tags: ALM,TFBS,TFS 2010

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  • Should we exclude code for the code coverage analysis?

    - by romaintaz
    I'm working on several applications, mainly legacy ones. Currently, their code coverage is quite low: generally between 10 and 50%. Since several weeks, we have recurrent discussions with the Bangalore teams (main part of the development is made offshore in India) regarding the exclusions of packages or classes for Cobertura (our code coverage tool, even if we are currently migrating to JaCoCo). Their point of view is the following: as they will not write any unit tests on some layers of the application (1), these layers should be simply excluded from the code coverage measure. In others words, they want to limit the code coverage measure to the code that is tested or should be tested. Also, when they work on unit test for a complex class, the benefits - purely in term of code coverage - will be unnoticed due in a large application. Reducing the scope of the code coverage will make this kind of effort more visible... The interest of this approach is that we will have a code coverage measure that indicates the current status of the part of the application we consider as testable. However, my point of view is that we are somehow faking the figures. This solution is an easy way to reach higher level of code coverage without any effort. Another point that bothers me is the following: if we show a coverage increase from one week to another, how can we tell if this good news is due to the good work of the developers, or simply due to new exclusions? In addition, we will not be able to know exactly what is considered in the code coverage measure. For example, if I have a 10,000 lines of code application with 40% of code coverage, I can deduct that 40% of my code base is tested (2). But what happen if we set exclusions? If the code coverage is now 60%, what can I deduct exactly? That 60% of my "important" code base is tested? How can I As far as I am concerned, I prefer to keep the "real" code coverage value, even if we can't be cheerful about it. In addition, thanks to Sonar, we can easily navigate in our code base and know, for any module / package / class, its own code coverage. But of course, the global code coverage will still be low. What is your opinion on that subject? How do you do on your projects? Thanks. (1) These layers are generally related to the UI / Java beans, etc. (2) I know that's not true. In fact, it only means that 40% of my code base

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  • Taking the fear out of a Cloud initiative through the use of security tools

    - by user736511
    Typical employees, constituents, and business owners  interact with online services at a level where their knowledge of back-end systems is low, and most of the times, there is no interest in knowing the systems' architecture.  Most application administrators, while partially responsible for these systems' upkeep, have very low interactions with them, at least at an operational, platform level.  Of greatest interest to these groups is the consistent, reliable, and manageable operation of the interfaces with which they communicate.  Introducing the "Cloud" topic in any evolving architecture automatically raises the concerns for data and identity security simply because of the perception that when owning the silicon, enterprises are not able to manage its content.  But is this really true?   In the majority of traditional architectures, data and applications that access it are physically distant from the organization that owns it.  It may reside in a shared data center, or a geographically convenient location that spans large organizations' connectivity capabilities.  In the end, very often, the model of a "traditional" architecture is fairly close to the "new" Cloud architecture.  Most notable difference is that by nature, a Cloud setup uses security as a core function, and not as a necessary add-on. Therefore, following best practices, one can say that data can be safer in the Cloud than in traditional, stove-piped environments where data access is segmented and difficult to audit. The caveat is, of course, what "best practices" consist of, and here is where Oracle's security tools are perfectly suited for the task.  Since Oracle's model is to support very large organizations, it is fundamentally concerned about distributed applications, databases etc and their security, and the related Identity Management Products, or DB Security options reflect that concept.  In the end, consumers of applications and their data are to be served more safely in a controlled Cloud environment, while realizing the many cost savings associated with it. Having very fast resources to serve them (such as the Exa* platform) makes the concept even more attractive.  Finally, if a Cloud strategy does not seem feasible, consider the pros and cons of a traditional vs. a Cloud architecture.  Using the exact same criteria and business goals/traditions, and with Oracle's technology, you might be hard pressed to justify maintaining the technical status quo on security alone. For additional information please visit Oracle's Cloud Security page at: http://www.oracle.com/us/technologies/cloud/cloud-security-428855.html

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  • SQL Injection - some sense at last!

    - by TATWORTH
    I see various articles that proclaim means to guard against SQL injection. As individual steps they are of use but since they were often proclaimed as "the solution" they were potentially misleading. At http://www.simple-talk.com/sql/learn-sql-server/sql-injection-defense-in-depth/ there is an article entitled "SQL Injection: Defense in Depth" - this article argues what I have argued myself. Remember that however low-grade the information on your web site is, if your site is hacked, the public may percive the hacking as your most sensitive information was exposed.

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  • Chrooted Drop Bear HowTo

    <b>Howtoforge:</b> "Dropbear is a relatively small SSH 2 server and client. It is an alternative lightweight program for openssh and it is designed for environments with low memory and processor resources, such as embedded systems."

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  • How To Watch Indian Union Budget 2011-2012 Live On Your PC

    - by Gopinath
    The Union Budget of India 2011-2012 will be tabled on Lok Sabha on 26th Feb, 2011. The finance minister, Mr. Pranab Muhkerjee will present the budget in the house and it will be broadcasted live on the TV channels(DD, NDTV, IBN Live and others) as well as on the web. For those who are willing to watch the budget session live on computers here is the required information. National Informatics Centre – Budget 2011 Live Web Cast Indian Government official stream of Union Budget 2011-2011 is available  at  http://budgetlive.nic.in/. This live stream will provide the budget information as is, without any masala, hype or so called analysis by experts sitting in private TV channel studios (and talking rubbish!) To view the primary live stream you need to install Windows Media Player plugin on your browser. As it’s a government website, better you use Internet Explorer browser to watch it. It may not work on Firefox or Chrome. Also the live stream is provided in other formats like Real Media and Flash. Here are the various streaming formats for you to choose Flash Player – High Bandwidth Stream Windows Media Player – Low Bandwidth Stream (IE browser is preferred) Windows Media Player – High Bandwidth Stream  (IE browser is preferred) Real Media Player – Low Bandwidth Stream Real Media Player – High Bandwidth Stream Indian Media Channels Covering Live Of Union Budget 2011 – 2012 Most of the news media channels live stream are available for free on the web, here are the few new channels you can watch live to follow Union Budget 2011 – 2012. NDTV 24 x 7 News Live Stream (English) NDTV India Live Streaming (Hindi) CNBC TV 18 Live Streaming (English) CNN IBN Live Streaming (English) IBN 7 Live Streaming (Hindi) Caution: In the name of analysis, most of the media channels mislead the viewers and provide base less information at times. Take utmost care in absorbing the information you see in any of the Indian news channel. This article titled,How To Watch Indian Union Budget 2011-2012 Live On Your PC, was originally published at Tech Dreams. Grab our rss feed or fan us on Facebook to get updates from us.

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  • Les opérateurs historiques versent des dividendes « colossaux » et investissent peu, selon Free Mobile qui répond aux attaques

    Free Mobile : Xavier Niel répond aux attaques des opérateurs historiques Qui verseraient des dividendes « colossaux » mais qui investiraient peu De nombreuses voix se sont exprimées contre Free Mobile depuis son lancement. Les syndicats de France Telecom (pour qui « Free Mobile prend les français pour des cons »). Les filiales pros de la concurrence (qui qualifient Free d'« offre low cost inadaptée aux PME »). Des universitaires,

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  • Migrate Your Site to TYPO3 CMS

    What else can you ask from a CMS system that gives you complete freedom from maintaining your site, coding, frequent changes, low cost of ownership, self administered back end and a lot more. This list can continue and go on and on. TYPO3 CMS has got many more advantages from the contemporary CMS systems. It is not only affable to the development community but also liked by most of the users who comes across this CMS.

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  • Media Streaming Server

    - by Ehsan
    I'm looking for a media stream server (specially audio streams) for installing on my Ubuntu server box. Is there any lightweight, easy configurable solution? It's awesome if this solution is able to install on a high bandwidth server and gets a stream from a low bandwidth server and serves it for many clients. (simply because the original server hasn't enough BW to serve media for many clients) (My server is a LAMP server, but I'm looking for a good solution for one of my clients to stream his audio for one hour every week)

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  • Tips on ensuring Model Quality

    - by [email protected]
    Given enough data that represents well the domain and models that reflect exactly the decision being optimized, models usually provide good predictions that ensure lift. Nevertheless, sometimes the modeling situation is less than ideal. In this blog entry we explore the problems found in a few such situations and how to avoid them.1 - The Model does not reflect the problem you are trying to solveFor example, you may be trying to solve the problem: "What product should I recommend to this customer" but your model learns on the problem: "Given that a customer has acquired our products, what is the likelihood for each product". In this case the model you built may be too far of a proxy for the problem you are really trying to solve. What you could do in this case is try to build a model based on the result from recommendations of products to customers. If there is not enough data from actual recommendations, you could use a hybrid approach in which you would use the [bad] proxy model until the recommendation model converges.2 - Data is not predictive enoughIf the inputs are not correlated with the output then the models may be unable to provide good predictions. For example, if the input is the phase of the moon and the weather and the output is what car did the customer buy, there may be no correlations found. In this case you should see a low quality model.The solution in this case is to include more relevant inputs.3 - Not enough cases seenIf the data learned does not include enough cases, at least 200 positive examples for each output, then the quality of recommendations may be low. The obvious solution is to include more data records. If this is not possible, then it may be possible to build a model based on the characteristics of the output choices rather than the choices themselves. For example, instead of using products as output, use the product category, price and brand name, and then combine these models.4 - Output leaking into input giving the false impression of good quality modelsIf the input data in the training includes values that have changed or are available only because the output happened, then you will find some strong correlations between the input and the output, but these strong correlations do not reflect the data that you will have available at decision (prediction) time. For example, if you are building a model to predict whether a web site visitor will succeed in registering, and the input includes the variable DaysSinceRegistration, and you learn when this variable has already been set, you will probably see a big correlation between having a Zero (or one) in this variable and the fact that registration was successful.The solution is to remove these variables from the input or make sure they reflect the value as of the time of decision and not after the result is known. 

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  • How To Build An Enterprise Application - Introduction

    - by Tuan Nguyen
    An enterprise application is a software which fulfills 4 core quality attributes: Reliability Flexibility Reusability Maintainability Reliability is the ability of a system or component to perform its required functions under stated conditions for a specific period of time. Because there are no ways more than testing to make sure a system is reliability, we can exchange the term reliability with the term testability. Flexibility is the ability of changing a system's core features without violating unrelated features or components. Although flexibility can helps us to achieve interoperability easily but the opposite is not true. For example, a program might run on multiple platforms, contains logic for many scenarios but that wouldn't mean it was flexibility if it forces us rewrite code in all components when we just want to change some aspects of a feature it had. Reusability is the ability of sharing one or more system's components for another system. We should just open a component's reusability in the context in which it is used. For example, we write classes that implement UI logic and deliver them to only classes which implementing UI. Maintainability is the ability of adding or removing features to a system after it was released. Maintainability consists of many factors such as readability, analyzability, extensibility therein extensibility is critical. Maintainability requires us to write code that is longer and complexer than normal but it doesn't mean we introduce unneccessarily complex code. We always try to make our code clear and transparent to everyone. An application enterprise is built on an enterprise design which consists of two parts: low-level design and high-level design. At low-level design, it focuses on building loose-coupled classes or components. Particularly, it recommends: Each class or component undertakes only single responsibility (design based on unit test) Classes or components implement and work through interfaces (design based on contract) Dependency relationship between classes and components could be injected at run-time (design based on dependency) At high-level design, it focuses on architecting system into tiers and layers. Particularly, it recommends: Divide system into subsystems for deployment. Each subsytem is called a tier. Typical, an enterprise application would have 3 tiers as illustrated in the following figure: Arrange classes and components to logical containers called layers. Typical, an enterprise application would have 5 layers as illustrated in the following figure

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  • The SPARC SuperCluster

    - by Karoly Vegh
    Oracle has been providing a lead in the Engineered Systems business for quite a while now, in accordance with the motto "Hardware and Software Engineered to Work Together." Indeed it is hard to find a better definition of these systems.  Allow me to summarize the idea. It is:  Build a compute platform optimized to run your technologies Develop application aware, intelligently caching storage components Take an impressively fast network technology interconnecting it with the compute nodes Tune the application to scale with the nodes to yet unseen performance Reduce the amount of data moving via compression Provide this all in a pre-integrated single product with a single-pane management interface All these ideas have been around in IT for quite some time now. The real Oracle advantage is adding the last one to put these all together. Oracle has built quite a portfolio of Engineered Systems, to run its technologies - and run those like they never ran before. In this post I'll focus on one of them that serves as a consolidation demigod, a multi-purpose engineered system.  As you probably have guessed, I am talking about the SPARC SuperCluster. It has many great features inherited from its predecessors, and it adds several new ones. Allow me to pick out and elaborate about some of the most interesting ones from a technological point of view.  I. It is the SPARC SuperCluster T4-4. That is, as compute nodes, it includes SPARC T4-4 servers that we learned to appreciate and respect for their features: The SPARC T4 CPUs: Each CPU has 8 cores, each core runs 8 threads. The SPARC T4-4 servers have 4 sockets. That is, a single compute node can in parallel, simultaneously  execute 256 threads. Now, a full-rack SPARC SuperCluster has 4 of these servers on board. Remember the keyword demigod.  While retaining the forerunner SPARC T3's exceptional throughput, the SPARC T4 CPUs raise the bar with single performance too - a humble 5x better one than their ancestors.  actually, the SPARC T4 CPU cores run in both single-threaded and multi-threaded mode, and switch between these two on-the-fly, fulfilling not only single-threaded OR multi-threaded applications' needs, but even mixed requirements (like in database workloads!). Data security, anyone? Every SPARC T4 CPU core has a built-in encryption engine, that is, encryption algorithms cast into silicon.  A PCI controller right on the chip for customers who need I/O performance.  Built-in, no-cost Virtualization:  Oracle VM for SPARC (the former LDoms or Logical Domains) is not a server-emulation virtualization technology but rather a serverpartitioning one, the hypervisor runs in the server firmware, and all the VMs' HW resources (I/O, CPU, memory) are accessed natively, without performance overhead.  This enables customers to run a number of Solaris 10 and Solaris 11 VMs separated, independent of each other within a physical server II. For Database performance, it includes Exadata Storage Cells - one of the main reasons why the Exadata Database Machine performs at diabolic speed. What makes them important? They provide DB backend storage for your Oracle Databases to run on the SPARC SuperCluster, that is what they are built and tuned for DB performance.  These storage cells are SQL-aware.  That is, if a SPARC T4 database compute node executes a query, it doesn't simply request tons of raw datablocks from the storage, filters the received data, and throws away most of it where the statement doesn't apply, but provides the SQL query to the storage node too. The storage cell software speaks SQL, that is, it is able to prefilter and through that transfer only the relevant data. With this, the traffic between database nodes and storage cells is reduced immensely. Less I/O is a good thing - as they say, all the CPUs of the world do one thing just as fast as any other - and that is waiting for I/O.  They don't only pre-filter, but also provide data preprocessing features - e.g. if a DB-node requests an aggregate of data, they can calculate it, and handover only the results, not the whole set. Again, less data to transfer.  They support the magical HCC, (Hybrid Columnar Compression). That is, data can be stored in a precompressed form on the storage. Less data to transfer.  Of course one can't simply rely on disks for performance, there is Flash Storage included there for caching.  III. The low latency, high-speed backbone network: InfiniBand, that interconnects all the members with: Real High Speed: 40 Gbit/s. Full Duplex, of course. Oh, and a really low latency.  RDMA. Remote Direct Memory Access. This technology allows the DB nodes to do exactly that. Remotely, directly placing SQL commands into the Memory of the storage cells. Dodging all the network-stack bottlenecks, avoiding overhead, placing requests directly into the process queue.  You can also run IP over InfiniBand if you please - that's the way the compute nodes can communicate with each other.  IV. Including a general-purpose storage too: the ZFSSA, which is a unified storage, providing NAS and SAN access too, with the following features:  NFS over RDMA over InfiniBand. Nothing is faster network-filesystem-wise.  All the ZFS features onboard, hybrid storage pools, compression, deduplication, snapshot, replication, NFS and CIFS shares Storageheads in a HA-Cluster configuration providing availability of the data  DTrace Live Analytics in a web-based Administration UI Being a general purpose application data storage for your non-database applications running on the SPARC SuperCluster over whichever protocol they prefer, easily replicating, snapshotting, cloning data for them.  There's a lot of great technology included in Oracle's SPARC SuperCluster, we have talked its interior through. As for external scalability: you can start with a half- of full- rack SPARC SuperCluster, and scale out to several racks - that is, stacking not separate full-rack SPARC SuperClusters, but extending always one large instance of the size of several full-racks. Yes, over InfiniBand network. Add racks as you grow.  What technologies shall run on it? SPARC SuperCluster is a general purpose scaleout consolidation/cloud environment. You can run Oracle Databases with RAC scaling, or Oracle Weblogic (end enjoy the SPARC T4's advantages to run Java). Remember, Oracle technologies have been integrated with the Oracle Engineered Systems - this is the Oracle on Oracle advantage. But you can run other software environments such as SAP if you please too. Run any application that runs on Oracle Solaris 10 or Solaris 11. Separate them in Virtual Machines, or even Oracle Solaris Zones, monitor and manage those from a central UI. Here the key takeaways once again: The SPARC SuperCluster: Is a pre-integrated Engineered System Contains SPARC T4-4 servers with built-in virtualization, cryptography, dynamic threading Contains the Exadata storage cells that intelligently offload the burden of the DB-nodes  Contains a highly available ZFS Storage Appliance, that provides SAN/NAS storage in a unified way Combines all these elements over a high-speed, low-latency backbone network implemented with InfiniBand Can grow from a single half-rack to several full-rack size Supports the consolidation of hundreds of applications To summarize: All these technologies are great by themselves, but the real value is like in every other Oracle Engineered System: Integration. All these technologies are tuned to perform together. Together they are way more than the sum of all - and a careful and actually very time consuming integration process is necessary to orchestrate all these for performance. The SPARC SuperCluster's goal is to enable infrastructure operations and offer a pre-integrated solution that can be architected and delivered in hours instead of months of evaluations and tests. The tedious and most importantly time and resource consuming part of the work - testing and evaluating - has been done.  Now go, provide services.   -- charlie  

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  • % new visitor vs. % returning visitor

    - by Torben Gundtofte-Bruun
    I'm not sure how to interpret the results in Google Analytics. I understand that some metrics should be high, and some should be low. But this one I don't get: % new visitor vs. % returning visitor: It's good that users are returning, but surely it's also good to get new, fresh visitors. How do I evaluate this %-vs-% ratio? The higher the better: visits unique visitors pageviews pages per visit avg. visit duration The lower the better: bounce rate drop-offs

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