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  • Walmart and Fusion Apps

    - by ultan o'broin
    Photograph: Misha Vaughan I attended Fusion Apps (yes, I know I am supposed to say "Oracle Fusion Applications", but stuffy old style guides are a turn-off in interwebs conversations) User Experience Advocate (FXA) training in Long Beach, California last week; a suitable location as ODTUG KSCOPE 11 was kicking off and key players were in the area. As a member of Oracle's Apps-UX team I know the Fusion Apps messaging, natch, and done some other Fusion Apps go-to-market content work too. For the messaging details themselves, see Lonneke Dikmans (@lonnekedikmans) great blog, by the way. However, I wanted some 'formal' training combined with the opportunity to meet and learn from people already out there delivering those messages. The idea in me reaching out to Misha Vaughan, Apps-UX FXA maven, to get me onto this training was that in addition to my UX knowledge, I could leverage my location in EMEA and hit up customer events more quickly and easily. Those local user groups do like to hear the voice of locals too you know (so I need to work on that mid-Atlantic accent). I'm looking forward to such opportunities. The training was all smashing stuff, just the right level of detail, delivered professionally and with great style and humor. I was especially honored to be paired off for my er, coaching with Debra Lilley (@debralilley), who shared with everyone all kinds of tips and insights from her experiences of delivering the message and demo. For me, that was the real power of the FXA event--the communal, conversational aspect--the meeting up with people who had done all this for real, the sharing in their experiences, while learning along with other newbies. Sorry, but that all-important social aspect doesn't work so well with remote meetings. Katie Candland (Apps-UX) gave us a great tour of the Fusion Apps demo and included some useful presentational tips too (any excuse to buy that iPad). It's clear to me that the Fusion Apps messaging and demos really come alive with real-world examples that local application users will recognize, and I picked up some "yes, that's my job made easier" scene-stealers from Debra and Karen Brownfield too, to add to the great ones already provided. This power of examples shouldn't surprise anyone, they've long been a mainstay of applications user assistance, popular with users. We'll offer customers different types of example topics in the Fusion Apps online help too (stay tuned), and we know from research how important those 3S's (stories, scenarios, and simulations) are to users when they consume and apply information. Well, we've got the simulation, now it's time for more stories and scenarios. If you get a chance to participate in an FXA event (whether you are an Oracle employee or otherwise), I'd encourage it. It's committing your time and energy for sure, but I got real bang for the buck from it for my everyday job too. Listening to the room's feedback on the application demo really brought our internal design work to life, and I picked up on some things that I need to follow up on (like how you alphabetically sort stuff in other languages). User experience is after all, about users. What will I be doing next, and what would I like to see happen? Obviously, I need to develop my story-telling links with the people I met in Long Beach and do some practicing with the materials, and then get out there and deliver them at a suitable location. The demo is what it is right now, and that's a super-rich demo that I know everyone will want to see and ask questions about. Then, as mentioned by attendees at the FXA event, follow up on those translated and localized messages for EMEA (and APAC), that deal with different statutory or reporting requirements of the target markets. Given my background I would say that, wouldn't I? However, language is part of the UX, and international revenue is greater than US-only revenue for Oracle, so yes dear, we all need to get over the fact that enterprise apps users don't all speak, or want to speak, American-English. Most importantly perhaps, the continued development of a strong messaging community between Oracle and partners and customers where we can swap and share those FXA messaging stories and scenarios about Fusion Apps in a conversational way. The more the better, a combination of online and face-to-face meetings. I must also mention the great dinner after the event at Parker's Lighthouse, and the fun myself and Andrew Gilmour (Apps-UX) had at our end of the table talking about just about everything except Fusion Apps with Ronald Van Luttikhuizen and Ben Prusinski (who now understands the difference between Cork and Dublin people. I hope). Thanks to all the Apps-UXers who helped bring the FXA training to town, and to Debra and all the others that I am too jetlagged to mention right who were instrumental in making it happen for me. Here's to the next one. And the Walmart angle? That was me doing my Robert Scoble (ScO'bilizer?)-style guerilla smart phone research in Walmart in Long Beach, before the FXA event. It's all about stories for me. You can read more about it on the appslab blog (see the comments).

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  • What is the supposed productivity gain of dynamic typing?

    - by hstoerr
    I often heard the claim that dynamically typed languages are more productive than statically typed languages. What are the reasons for this claim? Isn't it just tooling with modern concepts like convention over configuration, the use of functional programming, advanced programming models and use of consistent abstractions? Admittedly there is less clutter because the (for instance in Java) often redundant type declarations are not needed, but you can also omit most type declarations in statically typed languages that usw type inference, without loosing the other advantages of static typing. And all of this is available for modern statically typed languages like Scala as well. So: what is there to say for productivity with dynamic typing that really is an advantage of the type model itself?

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  • Why Healthcare Today Needs BPM and SOA by Avio

    - by JuergenKress
    Within the past couple years, the Patient Protection and Affordable Care Act has led to significant changes in the healthcare industry. A highly-complex supply chain between patients, providers, buyers and insurance companies has led to a lack of overall collaboration when it comes to processes. The first open enrollment deadline for products on the Health Insurance Exchange has passed. So what now? Let’s take a brief look at how things have changed and what organizations can do to stay in (and ahead of) the game. New requirements, new processes Organizations that have not adapted processes to meet new regulatory requirements will fall further behind. New regulatory requirements effectively make some legacy applications obsolete, require batch process to move to real-time, and more. Business Process Management (BPM) can help organizations bring data processes in line while helping IT redesign processes rather than change code or replace existing applications. BPM fills in application gaps and links critical information systems for a more visible, efficient and auditable organization. Social and mobile solutions BPM technology also facilitates social and mobile solutions that can help meet new needs. Patients are dependent on a network of doctors, pharmacists, families and others. Social solutions can connect members of the patient’s community in ways never seen before - enabling real-time, relevant communication. Likewise, mobile technology supports social solutions, and BPM is the most efficient way to make processes simple and role-based. It unties medical professionals from their offices by enabling them to access timely information and alerts anywhere. Why SOA is also needed Integrating BPM with Service-Oriented Architecture (SOA) also plays a critical role in the development of healthcare solutions that work. SOA can create a single end-to-end process, integrate applications and move them into a common workflow. While SOA enables the reutilization of existing IT infrastructure, BPM supports the process optimization, monitoring and social aspects. SOA and BPM applications support business analysts as they model, create and monitor processes - providing real-time insight and a unified workflow of process activities. Read “New” Solutions for a New Healthcare Landscape on our blog to learn more. SOA & BPM Partner Community For regular information on Oracle SOA Suite become a member in the SOA & BPM Partner Community for registration please visit www.oracle.com/goto/emea/soa (OPN account required) If you need support with your account please contact the Oracle Partner Business Center. Blog Twitter LinkedIn Facebook Wiki Technorati Tags: Avio,Healthcare,SOA Community,Oracle SOA,Oracle BPM,Community,OPN,Jürgen Kress

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  • Is software innovation still primarily North American and European? Why, and for how much longer?

    - by limist
    Since this site is read by a global audience of programmers, I want to know if people generally agree that the vast majority of software innovation - languages, OS, tools, methodologies, books, etc. - still originates from the USA, Canada, and the EU. I can think of a few exceptions, e.g. Nginx webserver from Russia and the Ruby language from Japan, but overwhelmingly, the software I use and encounter daily is from North America and the EU. Why? Is history and historical momentum (computing having started in USA and Europe) still driving the industry? And/or, is some nebulous (or real) cultural difference discouraging software innovation abroad? Or are those of us in the West simply ignorant of real software innovation going on in Asia, South America, Eastern Europe, etc.? When, if ever, might the centers of innovation move out of the West? Your experiences and opinions welcome, thanks!

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  • What all items can I put on my resume without it looking tacky? [closed]

    - by Earlz
    I've been searching for work, and so far it's very hard for me to even get a call back. So, I'm looking at adding things to my resume. I know a resume doesn't need to be over 2 pages. I have the basics: Objective/personal info General skills (languages known, etc) Work experience Some things I'm considering adding to it: My college education (though I don't have a degree) Awards given for programming skills in high school (curriculum contests and AP test scores) Open source projects? Would any of these 3 items look tacky? And I only have about 1.5 years of work experience, but I've been programming since I was 13. Is there anything else I can add to my resume that would give me a better chance of getting my foot in the door?

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  • Why does this script not open parallel gnome-terminals on a server?

    - by broiyan
    Why am I not able to have parallel gnome-terminals on my server while I can on my client. Here is a test that illustrates the problem. #!/bin/bash # this is the parent script gnome-terminal --command "./left.sh" sleep 10 gnome-terminal --command "./right.sh" #!/bin/bash echo "this is the left script" read -p "press any key to close this terminal" key #!/bin/bash echo "this is the right script" read -p "press any key to close this terminal" key When I run this on a regular ubuntu desktop (maverick) I see two terminals after 10 seconds. When I run this on a maverick server at a server farm, the second window does not appear until after I close the first one and wait 10 seconds. I am using tightvncserver to view the server desktop. (I could have simplified a bit more. The 10 second sleep is extraneous to the problem. In my real world application I need the first terminal to do some real work before starting the second. The problem probably still exists even if there is no sleep.)

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  • career advice for PhD scientist seeking to program?

    - by C SD
    I'm largely a self-taught programmer. In fact, I first started programming about half way through biophysics grad school, and even though I think I've done some pretty nice work, I've never worked as part of a 'serious' development team that had more than one or two other developers (and I wouldn't hesitate to call them equally inexperienced in software development as a profession). After finishing my PhD I applied to Google, on a lark, since I had some confidence in my abilities, if not necessarily my experience, and I was hoping to maybe slip in and absorb all the experience and talent I'd be surrounded with and become productive enough, quickly enough, that they wouldn't immediately regret their decision. I was excited to actually get invited to interview up at Mountain View (this was ~ mid 2008). Overall, my memory of the interview was very positive, but after close to a three month wait (is that normal?) they ended up turning me down. I wasn't too surprised or disappointed (aside from the uncomfortably long wait) given my unusual background and admitted lack of experience. I decided to continue as a postdoc, but focus on improving my skills rather than doing research. I've done about three years of that, and my honest assessment is that I've learned a ton more, but I really need more of a peer group to maintain or accelerate my growth. Google invited me to interview again about eight months ago, and the interview process went even better than the first time around (I thought), though they again declined to give me an offer. I have to admit this second rejection was much more discouraging. They had insisted I interview even after I mentioned to them that a move on my part was unlikely given that I had bought a house, gotten married, etc. since the first interview. I guess I was hoping they'd at least give me an offer that I could parlay into a more conventional, but still interesting, programming position close to home. So here I am, going on my third year out of grad school, a glorified postdoc and I'm starting to get pretty discouraged. Even though I could technically get 'back-on-track' for a career in science, I have been focusing the vast majority of this time on gaining programming experience rather than on research and publications. The problem is, whenever I look, most job listings have requirements that seem impossibly grandiose and I hesitate to apply. That, or the job/project seems incredibly dull. Ironically, applying to Google struck me as less intimidating. I suspect that either most people are just a lot less realistic than I am when it comes to assessing how long it will take for them to get up to speed, or they don't care; my fear is that I'm just woefully unqualified for any interesting, well paying work. IE: I'm confident I could switch fully back into C++ mode with a couple weeks work (I mostly use C,Python,C# daily) but I don't list myself as being 'proficient' in C++ on my CV, or applying for jobs that 'require' such knowledge. The few applications for which I did feel I was a legitimately good match have not elicited a response. I suspect the following things are potential problems with my application/CV and I would like feedback on: I don't have a CS degree. My BS was in biochemistry and molecular biology, my PhD in biophysics. I took a undergrad and grad level CS course at UCSD and completely killed them, but I don't know how to translate that to my CV effectively. I have a PhD, but it's not in CS... I've been debating if I should remove it from my CV, and wether or not it would then be misleading to list at least some of those years as some kind of 'programming' job (in many respects it was). I think there are sometimes strong stigmas associated with 'self-taught' programmers. I am certainly one of those. I even recognize that some of those stigmas hold a hint of truth, but I really do want to be an asset to a team. How do I communicate that even though I have been largely self-directing for ~8 years I can still take marching orders when needed? Do I just say so outright? Should I just become a lot less scrupulous about the whole process? anecdote: I have a friend who applied for positions where he completely fudged his qualifications to get past the first culling. He was much more honest and forthcoming about his actual qualifications when contacted and he still managed to get invited to a couple of interviews and even got some offers. His balls are larger than mine though.

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  • What benefits does a game design degree have for a hobby game programmer?

    - by sm4
    I am interested in studying game design, not because I want a job in the games industry, but because I am interested in the subject itself. I read the following questions, but they mostly deal with the effects on your career in game industry. Should I consider a graduate degree in game development? Game Development Degree vs Computer Science Degree First I thought a game development degree could be beneficial. But from the websites of colleges that offer such degrees, I feel like its more about basic programming with examples from games. This college offers game design degrees, for example. My question is, can I benefit from such a degree when I already have a degree in Computer Science, I already know programming, I'm already developing a game and finally, I have this site to help me when I get stuck?

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  • asus n550jv audio problem: no sound from notebook' speakers

    - by skywalker
    Ubuntu 13.10. The problem is: the internal speakers don't work. I have no problem when I'm using the headphones. There is no hardware issue since in windows 8 everything works perfectly(external subwoofer included). I'm trying to modify /etc/modprobe.d/alsa-base.conf but I can't find the correct model to put into: options snd-hda-intel model= The file HD-Audio-Models.txt doesn't contain the model for ALC668. Some info: :~sudo aplay -l **** List of PLAYBACK Hardware Devices **** card 0: MID [HDA Intel MID], device 3: HDMI 0 [HDMI 0] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: MID [HDA Intel MID], device 7: HDMI 1 [HDMI 1] Subdevices: 1/1 Subdevice #0: subdevice #0 card 0: MID [HDA Intel MID], device 8: HDMI 2 [HDMI 2] Subdevices: 1/1 Subdevice #0: subdevice #0 card 1: PCH [HDA Intel PCH], device 0: ALC668 Analog [ALC668 Analog] Subdevices: 0/1 Subdevice #0: subdevice #0 :~$ sudo lspci -v | grep -A7 -i "audio" 00:03.0 Audio device: Intel Corporation Xeon E3-1200 v3/4th Gen Core Processor HD Audio Controller (rev 06) Subsystem: Intel Corporation Device 2010 Flags: bus master, fast devsel, latency 0, IRQ 52 Memory at f7a14000 (64-bit, non-prefetchable) [size=16K] Capabilities: [50] Power Management version 2 Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit- Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00 Kernel driver in use: snd_hda_intel -- 00:1b.0 Audio device: Intel Corporation 8 Series/C220 Series Chipset High Definition Audio Controller (rev 04) Subsystem: ASUSTeK Computer Inc. Device 11cd Flags: bus master, fast devsel, latency 0, IRQ 53 Memory at f7a10000 (64-bit, non-prefetchable) [size=16K] Capabilities: [50] Power Management version 2 Capabilities: [60] MSI: Enable+ Count=1/1 Maskable- 64bit+ Capabilities: [70] Express Root Complex Integrated Endpoint, MSI 00 Capabilities: [100] Virtual Channel PS info :~$ amixer -c 0 Simple mixer control 'IEC958',0 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] Simple mixer control 'IEC958',1 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] Simple mixer control 'IEC958',2 Capabilities: pswitch pswitch-joined Playback channels: Mono Mono: Playback [on] :~$ pacmd dump-volumes Welcome to PulseAudio! Use "help" for usage information. Sink 0: reference = 0: 76% 1: 76%, real = 0: 76% 1: 76%, soft = 0: 100% 1: 100%, current_hw = 0: 76% 1: 76%, save = yes Input 8: volume = 0: 100% 1: 100%, reference_ratio = 0: 100% 1: 100%, real_ratio = 0: 100% 1: 100%, soft = 0: 100% 1: 100%, volume_factor = 0: 100% 1: 100%, volume_factor_sink = 0: 100% 1: 100%, save = no Source 0: reference = 0: 100% 1: 100%, real = 0: 100% 1: 100%, soft = 0: 100% 1: 100%, current_hw = 0: 100% 1: 100%, save = no Source 1: reference = 0: 16% 1: 16%, real = 0: 16% 1: 16%, soft = 0: 100% 1: 100%, current_hw = 0: 16% 1: 16%, save = yes

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  • Using machine learning to aim mirrors in a solar array?

    - by Buttons840
    I've been thinking about solar collectors where several independent mirrors to focus the light on a solar collector, similar to the following design from Energy Innovations. Because there will be flaws in the assembly of this solar array, I am proceeding with the following assumptions (or lack thereof): The software knows the "position" of each mirror, but doesn't know how this position relates to the real world or to other mirrors. This will account for poor mirror calibration or other environmental factors which may effect one mirror but not the others. If a mirror moves 10 units in one direction, and then 10 units in the opposite direction, it will end up where it originally started. I would like to use machine learning to position the mirrors correctly and focus the light on the collector. I expect I would approach this as an optimization problem, optimizing the mirror positions to maximize the heat inside the collector and the power output. The problem is finding a small target in a noisy high-dimensional space (considering each mirror has 2 axis of rotation). Some of the problems I anticipate are: cloudy days, even if you stumble upon the perfect mirror alignment, it might be cloudy at the time noisy sensor data the sun is a moving target, it moves along a path, and follows a different path every day - although you could calculate the exact position of the sun at any time, you wouldn't know how that position relates to your mirrors My question isn't about the solar array, but possible machine learning techniques that would help in this "small target in a noisy high dimensional-space" problem. I mentioned the solar array because it was the catalyst for this question and a good example. What machine learning techniques can find such a small target in a noisy high-dimensional space? EDIT: A few additional thoughts: Yes, you can calculate the suns position in the real world, but you don't know how the mirrors position is related to the real world (unless you've learned it somehow). You might know the suns azimuth is 220 degrees, and the suns elevation is 60 degrees, and you might know a mirror is at position (-20, 42); now tell me, is that mirror correctly aligned with the sun? You don't know. Lets assume you have some very sophisticated heat measurements, and you know "with this heat level, there must be 2 mirrors correctly aligned". Now the question is, which two mirrors (out of 25 or more) are correctly aligned? One solution I considered was to approximate the correct "alignment function" using a neural network which would take the suns azimuth and elevation as input and output a large array with 2 values for each mirror which correspond to the 2 axis of each mirror. I'm not sure what the best training method is though.

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  • Finding work as a college student

    - by lightburst
    I'm a 3rd year CS student. I'm currently really, really, bored and tired of cheap school programming(I go to a fairly respectable(albeit not top) university in my country, but, really, it's not MIT) so I've been thinking about getting a part-time dev job for a long while now. I'm not some hotshot programmer or anything, but "Add/Delete XYZ class objects to list" or "Do this web feature/pattern in PHP" does get old after a few semesters. I also only learned(heard?) of programming when I entered college, so the duration of me being in contact with any code is short. I can't really apply as an intern as I have not accumulated the necessary credits yet to do that so I was thinking of selling myself as a part-time dev. I still need to go to school, and don't want to subject myself to living two lives. Plus, I think I'd have better chances considering my lack of things to write on the resume. The only language I know at heart is C (I've written several pointer-oriented stuff on my freshman year, which is apparently pretty leet(for some reason), or so Joel says. That sort of boosted my morale a bit) but I've worked with several other languages only for the sake of course work such as C#/Java/PHP/ASM. My only user-worthy project was a recursive quicksort simulator I wrote for class using GTK+ that used a textbox to output the progress. I also have not taken the compiler theory class yet, or my thesis. All that being said, I wonder if any legitimate software company(big or small) would hire somebody like me considering all that. If there are companies that do accept anybody like me, would I be doing programming or maybe just be a tester or something? Would anybody hire me as a dev at all? I know I don't have much(not even a degree) but what I lack in experience, I compensate with interest? I am less interested in websites and 'management' software(no offense or anything. also, most of the places here ONLY have those), and more into 'process driven'(I'm not sure how to call it) and system software. I have my eyes on a startup that sells basically an extension of Google Drive, but I feel like I'm too 'risky' for them. Oh, I'm also 19 if that means anything. We're not K-12 so kids go to college earlier than in the US.

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  • Confused about career options in Web Developement.

    - by Radheshyam Nayak
    I am currently in the final year of my graduation in computer science course. I love programming in PHP but not under pressure. As my graduation life is going to be over I have to shape up my career. My personal desire is to become a web developer and start my own web-based company after completion of courses. I do not have any desire to work for a company as a developer. Currently I have programming knowledge of PHP, Mysql and Javascript. Though I have not completed any type of project in PHP. So to become a complete web developer what else do I need to know to be able to get developement project? Any project I apply for are simply declined due to lack of portfolio. So how should I proceed?

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  • Do I deserve a promotion/higher salary?

    - by anonCoder
    I'm a software developer and have been working at my current employer for almost 2 years. I joined straight out of university, so this is my first real full-time job. I was employed as a junior developer with no real responsibilities. In the last year, I have been given more responsiibility. I am the official contact person at my company for a number of clients. I have represented the company by myself in off-site meetings with clients. My software development role has grown. I now have specialised knowledge in certain tools/products/technologies that no one else here does. My problem is that I am still officially a junior developer, and still earning less than I feel I am worth. Am I being taken advantage of? How long should I reasonably expect to stay a junior developer before I expect a promotion of some kind? What would you do in my situation?

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  • what is message passing in OO?

    - by Tom
    I've been studying OO programming, primarily in C++, C# and Java. I thought I had a good grasp on it with my understanding of encapsulation, inheritance and polymorphism (as well as reading a lot of questions on this site). One thing that seems to popup up here and there is the concept of "message passing". Apparently, this is something that is not used whilst OO programming in today's mainstream languages, but is supported by Smalltalk. My questions are: What is message passing? (Can someone give a practical example?) Is there any support for this "message passing" in C++, C# or Java?

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  • Extending SSIS with custom Data Flow components (Presentation)

    Download the slides and sample code from my Extending SSIS with custom Data Flow components presentation, first presented at the SQLBits II (The SQL) Community Conference. Abstract Get some real-world insights into developing data flow components for SSIS. This starts with an introduction to the data flow pipeline engine, and explains the real differences between adapters and the three sub-types of transformation. Understanding how the different types of component behave and manage data is key to writing components of your own, and probably should but be required knowledge for anyone building packages at all. Using sample code throughout, I will show you how to write components, as well as highlighting best practice and lessons learned. The sample code includes fully working example projects for source, destination and transformation components. Presentation & Samples (358KB) Extending SSIS with custom Data Flow components.zip

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  • Maker Faire 2012 Attendees build with Java Technology

    - by hinkmond
    Looks like Daniel Green, systems engineer from Oracle, and the panel of Java experts had a successful Java Technology booth at this year's Maker Faire 2012. See: Maker Faire 2012 adds Java Here's a quote: "We made a huge impact for Java and Oracle, creating positive perception, building brand awareness, and introducing fun and engaging ways for future technologists to learn Java programming," says Michelle Kovac, Oracle director, Java Marketing and Operations. Good stuff, considering all the future developers of exploding robots and fire-breathing dragon metal sculptures attend the Maker Faire. They can blow up stuff with Java technology just as effectively as other programming languages. Hinkmond

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  • Returning JsonResult From ASP.NET MVC 2.0 Controller and Unit Testing

    This post will show how to return a simple Json result from an ASP.NET MVC 2.0 web project.  It will show how to test that result inside a unit test and essentially pick apart the Json, just... This site is a resource for asp.net web programming. It has examples by Peter Kellner of techniques for high performance programming...Did you know that DotNetSlackers also publishes .net articles written by top known .net Authors? We already have over 80 articles in several categories including Silverlight. Take a look: here.

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  • Solving Big Problems with Oracle R Enterprise, Part I

    - by dbayard
    Abstract: This blog post will show how we used Oracle R Enterprise to tackle a customer’s big calculation problem across a big data set. Overview: Databases are great for managing large amounts of data in a central place with rigorous enterprise-level controls.  R is great for doing advanced computations.  Sometimes you need to do advanced computations on large amounts of data, subject to rigorous enterprise-level concerns.  This blog post shows how Oracle R Enterprise enables R plus the Oracle Database enabled us to do some pretty sophisticated calculations across 1 million accounts (each with many detailed records) in minutes. The problem: A financial services customer of mine has a need to calculate the historical internal rate of return (IRR) for its customers’ portfolios.  This information is needed for customer statements and the online web application.  In the past, they had solved this with a home-grown application that pulled trade and account data out of their data warehouse and ran the calculations.  But this home-grown application was not able to do this fast enough, plus it was a challenge for them to write and maintain the code that did the IRR calculation. IRR – a problem that R is good at solving: Internal Rate of Return is an interesting calculation in that in most real-world scenarios it is impractical to calculate exactly.  Rather, IRR is a calculation where approximation techniques need to be used.  In this blog post, we will discuss calculating the “money weighted rate of return” but in the actual customer proof of concept we used R to calculate both money weighted rate of returns and time weighted rate of returns.  You can learn more about the money weighted rate of returns here: http://www.wikinvest.com/wiki/Money-weighted_return First Steps- Calculating IRR in R We will start with calculating the IRR in standalone/desktop R.  In our second post, we will show how to take this desktop R function, deploy it to an Oracle Database, and make it work at real-world scale.  The first step we did was to get some sample data.  For a historical IRR calculation, you have a balances and cash flows.  In our case, the customer provided us with several accounts worth of sample data in Microsoft Excel.      The above figure shows part of the spreadsheet of sample data.  The data provides balances and cash flows for a sample account (BMV=beginning market value. FLOW=cash flow in/out of account. EMV=ending market value). Once we had the sample spreadsheet, the next step we did was to read the Excel data into R.  This is something that R does well.  R offers multiple ways to work with spreadsheet data.  For instance, one could save the spreadsheet as a .csv file.  In our case, the customer provided a spreadsheet file containing multiple sheets where each sheet provided data for a different sample account.  To handle this easily, we took advantage of the RODBC package which allowed us to read the Excel data sheet-by-sheet without having to create individual .csv files.  We wrote ourselves a little helper function called getsheet() around the RODBC package.  Then we loaded all of the sample accounts into a data.frame called SimpleMWRRData. Writing the IRR function At this point, it was time to write the money weighted rate of return (MWRR) function itself.  The definition of MWRR is easily found on the internet or if you are old school you can look in an investment performance text book.  In the customer proof, we based our calculations off the ones defined in the The Handbook of Investment Performance: A User’s Guide by David Spaulding since this is the reference book used by the customer.  (One of the nice things we found during the course of this proof-of-concept is that by using R to write our IRR functions we could easily incorporate the specific variations and business rules of the customer into the calculation.) The key thing with calculating IRR is the need to solve a complex equation with a numerical approximation technique.  For IRR, you need to find the value of the rate of return (r) that sets the Net Present Value of all the flows in and out of the account to zero.  With R, we solve this by defining our NPV function: where bmv is the beginning market value, cf is a vector of cash flows, t is a vector of time (relative to the beginning), emv is the ending market value, and tend is the ending time. Since solving for r is a one-dimensional optimization problem, we decided to take advantage of R’s optimize method (http://stat.ethz.ch/R-manual/R-patched/library/stats/html/optimize.html). The optimize method can be used to find a minimum or maximum; to find the value of r where our npv function is closest to zero, we wrapped our npv function inside the abs function and asked optimize to find the minimum.  Here is an example of using optimize: where low and high are scalars that indicate the range to search for an answer.   To test this out, we need to set values for bmv, cf, t, emv, tend, low, and high.  We will set low and high to some reasonable defaults. For example, this account had a negative 2.2% money weighted rate of return. Enhancing and Packaging the IRR function With numerical approximation methods like optimize, sometimes you will not be able to find an answer with your initial set of inputs.  To account for this, our approach was to first try to find an answer for r within a narrow range, then if we did not find an answer, try calling optimize() again with a broader range.  See the R help page on optimize()  for more details about the search range and its algorithm. At this point, we can now write a simplified version of our MWRR function.  (Our real-world version is  more sophisticated in that it calculates rate of returns for 5 different time periods [since inception, last quarter, year-to-date, last year, year before last year] in a single invocation.  In our actual customer proof, we also defined time-weighted rate of return calculations.  The beauty of R is that it was very easy to add these enhancements and additional calculations to our IRR package.)To simplify code deployment, we then created a new package of our IRR functions and sample data.  For this blog post, we only need to include our SimpleMWRR function and our SimpleMWRRData sample data.  We created the shell of the package by calling: To turn this package skeleton into something usable, at a minimum you need to edit the SimpleMWRR.Rd and SimpleMWRRData.Rd files in the \man subdirectory.  In those files, you need to at least provide a value for the “title” section. Once that is done, you can change directory to the IRR directory and type at the command-line: The myIRR package for this blog post (which has both SimpleMWRR source and SimpleMWRRData sample data) is downloadable from here: myIRR package Testing the myIRR package Here is an example of testing our IRR function once it was converted to an installable package: Calculating IRR for All the Accounts So far, we have shown how to calculate IRR for a single account.  The real-world issue is how do you calculate IRR for all of the accounts?This is the kind of situation where we can leverage the “Split-Apply-Combine” approach (see http://www.cscs.umich.edu/~crshalizi/weblog/815.html).  Given that our sample data can fit in memory, one easy approach is to use R’s “by” function.  (Other approaches to Split-Apply-Combine such as plyr can also be used.  See http://4dpiecharts.com/2011/12/16/a-quick-primer-on-split-apply-combine-problems/). Here is an example showing the use of “by” to calculate the money weighted rate of return for each account in our sample data set.  Recap and Next Steps At this point, you’ve seen the power of R being used to calculate IRR.  There were several good things: R could easily work with the spreadsheets of sample data we were given R’s optimize() function provided a nice way to solve for IRR- it was both fast and allowed us to avoid having to code our own iterative approximation algorithm R was a convenient language to express the customer-specific variations, business-rules, and exceptions that often occur in real-world calculations- these could be easily added to our IRR functions The Split-Apply-Combine technique can be used to perform calculations of IRR for multiple accounts at once. However, there are several challenges yet to be conquered at this point in our story: The actual data that needs to be used lives in a database, not in a spreadsheet The actual data is much, much bigger- too big to fit into the normal R memory space and too big to want to move across the network The overall process needs to run fast- much faster than a single processor The actual data needs to be kept secured- another reason to not want to move it from the database and across the network And the process of calculating the IRR needs to be integrated together with other database ETL activities, so that IRR’s can be calculated as part of the data warehouse refresh processes In our next blog post in this series, we will show you how Oracle R Enterprise solved these challenges.

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  • Are there any books dedicated to writing test code? [on hold]

    - by joshin4colours
    There are many programming books dedicated to useful programming and engineering topics, like working with legacy code or particular languages. The best of these books become "standard" or "canonical" references for professional programmers. Are there any books like this (or that could be like this) for writing test code? I don't mean books about Test-Driven Development, nor do I mean books about writing good (clean) code in general. I'm looking for books that discuss test code specifically (unit-level, integration-level, UI-level, design patterns, code structures and organization, etc.)

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