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Factors of Bluetooth Technology to Mitigate Interference with Wi-Fi

Bluetooth wireless technology (BT) operates in the unlicensed Industrial, Scientific, Medical (ISM) band in the 2.4GHz frequency range. It randomly uses 79 1Mhz wide channels ranging from 2.402MHz to 2.480MHz. Each channel is occupied for a maximum time slot of 625us. During this time the radio must change the operating frequency, receive or transmit data, and provide enough off time before switching to the next hop frequency. In reality, the time the radio is actually transmitting on a given channel is much less and is dependent on the amount of data being transmitted. WIFI WiFi or 802.11 b/g, also operates in the same ISM band as BT. Due to complicated modulation techniques, 802.11g channels are 20MHz wide while 802.11b channels are 22MHz wide. This means a common WiFi channel can occupy from 20 to 22 BT channels. COURTESY: HTTP://EN.WIKIPEDIA.ORG/ WIKI/IEEE_802.11B-1999 INTERFERENCE For an RF signal to be received by the radios receiver, the RF signal must contain enough energy to be detected by the receiver circuit. The minimum receive level is known as the receivers sensitivity. This is similar to the lowest whisper that a human ear can detect. What if there happens to be two signals present at the same time and both are greater than the receiver’s sensitivity? Which signal will the radio detect? One would think that it would not be able to correctly detect either signal. That would be true if both signals are close to the same power level. If one signal had a higher power level than the other signal by a specific amount, the radio would be able to detect the more powerful signal. This is similar to a human ear being able to clearly understand members at a dinner table while there are many others talking at tables that are further away. The minimum ratio of power level for two signals when a radio can correctly detect the desired signal is known as the carrier/interferer ratio, or C/I. This means that two RF signals can exist on the same frequency at the same time without causing interference if the ratio of their power levels meet the radios C/I specification.

Science Olympiad Robots
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Okay, so what is a robot? Per definition of en.wikipedia.org, the Holder of All Human Knowledge, a robot is: a mechanical device that can perform physical tasks. A robot may act under the direct control of a human (eg. the robotic arm of the space shuttle) or autonomously under the control of a pre-programmed computer. In the context of Science Olympiad and other small engineering competitions, we are looking at the first type, human control. There are plenty of opportunities to put autonomous features into a Science Olympiad robot, but if you are reading this for content, it is likely beyond your scope and unnecessary. Therefore, for the purposes of this text only, a robot will be defined as: A mechanical device, operated under the direct control of a human, that is engineered to perform a specific task or accomplish a goal. In this case, the goal is to compete in Science Olympiad's Robot Ramble event. And win. More on that later. I'm not smart enough to build a robot! Yes you are. Modern technology has developed to the point at which it permeates our lives. One side effect of this is that it is much easier to learn and try out than in years past. The hobby robotics market is only increasing, and there are a number of companies that specifically make products catered to robots and their builders. Full directions and kits are available to build or program small robots. In some cases, they're even premade, and all you have to do is mess with them. This is often the best way to go about learning.

Very old Ricoh camera and lenses to work with newer DSLR ... - Rqna

Asked by SixfootJames on 2012-10-24T11:49:33-04:00 I've been given an old bag of Ricoh camera and lenses and I find that it would be such a waste not to be able to use in some way all this again for something. Can you give me some suggestions as to how to use this kind of equipment with a newer camera like a Canon 600D? Archives Arts Questions and Answers Photography Questions and Answers Oct 24th, 2012 Archives Week 43, 2012 Archives October, 2012 Archives Tags Lens Dslr Old Lenses Best Answer Answered by John Cavan on 2012-10-24T23:11:20-04:00 Ricoh, historically, used the Pentax K-mount for their film SLR cameras, but with a slight and important modification: they added a pin that's used to indicate the aperture is in auto mode for shutter priority use. With some careful work, you can http://forums.dpreview.com/forums/post/25959708 for use on K-mount bodies made by Pentax or Samsung or with a http://rads.stackoverflow.com/amzn/click/B003Y3EJMU for Canon EOS digital and film variants. Nevertheless, if you have Ricoh K-mount lenses, that pin has to go. You can confirm if you have these based on this helpful bit of info from Wikipedia: The R-K mount is used on Rikenon P lenses, Ricoh bodies that include the letter 'P' in their model number, and some non-Ricoh lenses. Now, it's also possible that the Ricoh lenses are M42 screw-mount lenses also known, funny enough, as the Pentax mount when most film cameras had it and Pentax was the SLR king. If that is the case, and it's easy to tell by just looking for threads on the lens mount, then you can easily get...

The Horde 4 PHP framework
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The Horde 4 PHP framework. Gunnar Wrobel wrobel@horde.org. May, 13th 2011 . Gunnar Wrobel (wrobel@horde.org). Horde 4. May, 13th 2011. 1 / 44 ... The Horde 4 PHP framework Gunnar Wrobel wrobel@horde.org May, 13th 2011 Gunnar Wrobel (wrobel@horde.org) Horde 4 May, 13th 2011 1 / 44 Components Components = Modules = Libraries = Packages = ... Photo: Rudolf Ammann [http://www.flickr.com/photos/rka/1415516/] Gunnar Wrobel (wrobel@horde.org) Horde 4 May, 13th 2011 2 / 44 The Horde 4 PHP framework There are more than 90 components available from http://pear.horde.org. Photo: Aaron Merrifield [http://www.flickr.com/photos/spammt/4823025103/] Gunnar Wrobel (wrobel@horde.org) Horde 4 May, 13th 2011 3 / 44 Groupware Photo: Denise Chan [http://www.flickr.com/photos/denn/5005046/] Gunnar Wrobel (wrobel@horde.org) Horde 4 May, 13th 2011 4 / 44 Groupware Definition “[...] groupware [...] is computer software designed to help people involved in a common task achieve their goals [...].”a a http://en.wikipedia.org/wiki/Groupware Remote It is usually associated with team members not physically co-located. Asynchronous Communication between team members is primarily asynchronous. Gunnar Wrobel (wrobel@horde.org) Horde 4 May, 13th 2011 5 / 44

Analyzing Design Tradeoffs in Large-scale Socio ... - Christoph Dorn

Emerging online collaboration platforms such as Wikipedia, Twitter, or Facebook provide the foundation for socio-technical systems where humans have become both content consumer and provider. Existing software engineering tools and techniques support the system engineer in designing and assessing the technical infrastructure. Little research, however, addresses the engineer’s need for understanding the overall socio-technical system behavior. The effect of fundamental design decisions becomes quickly unpredictable as multiple collaboration patterns become integrated into a single system. We propose the simulation of human and software elements at the collaboration level. We aim for detecting and evaluating undesirable system behavior such as users experiencing repeated update conflicts or software components becoming overloaded. To this end, this paper contributes (i) a language and (ii) methodology for specifying and simulating large-scale collaboration structures, (iii) example individual and aggregated pattern simulations, and (iv) evaluation of the overall approach. Keywords: Design Tools and Techniques, System Simulation, Collaboration Patterns, Large-scale Socio-Technical Systems

Tech City UK names Global Personals Ltd in Future Fifty fast-track

Tech City UK has named Global Personals Ltd in the second wave of 25 companies to join the Future Fifty programme, which matches high potential growth-stage businesses with bespoke public and private sector support. Visit: http://en.wikipedia.org/wiki/WhiteLabelDating

Global Personals / International Social Discovery

Global Personals provide social discovery and dating networks to countries on no less than four continents across the globe. Members of a Global Personals website can choose to focus their searches on people in their local area with a view to meeting personally once a relationship has been established. Visit: http://en.wikipedia.org/wiki/Global_Personals

Zend_Cache: how to improve the performance of ... - Enrico Zimuel

Zend_Cache: how to improve the performance of PHP applications by Enrico Zimuel (enrico.z@zend.com) Senior Consultant ­ Zend Technologies October 31th, PHP Barcelona Conference - 2009 Copyright © 2007, Zend Technologies Inc. About me Enrico Zimuel • I come from Turin (Italy). • Senior Consultant at Zend Technologies in Italy. • Software Engineer since 1996. • Open source contributor: XCheck, Core XPath • I was a Research Programmer at the Informatics Institute of the University of Amsterdam. • ZCE, ZFCE also proficiency in C/C++, Java, Perl, Javascript. • B.Sc. in Computer Science and Economics My website: http://www.zimuel.it ­ Blog: http://www.zimuel.it/blog Summary • Keys of performance of a PHP application • The caching mechanism • Zend Framework and Zend_Cache • Using the Zend_Cache to cache data and pages • Benchmarking different caching: Files, APC, Memcache, Zend Server CE Name of this section | | 3 Nov 2, 2009 Performance • How to improve the performance of a PHP application or more in general a piece of software?  Optimize the code (make the code faster)  Using a caching mechanism (reduce the amount of code to execute) Name of this section | | 4 Nov 2, 2009 What's a cache? • In computer science, a cache is a collection of data duplicating original values, stored elsewhere or computed earlier, where the original data is expensive to fetch (owing to longer access time) or to compute, compared to the cost of reading the cache From Wikipedia, the free encyclopedia Name of this section | | 5 Nov 2, 2009...

October 2013 issue - Doherty High School

Did you miss your chance to join newspaper, or do you just want to be a published writer? Send stories and contact info. to dohertyspectrum@ gmail.com for a chance to be publish in next month’s issue! T he fourth amendment of the constitution states, “The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable searches and seizures, shall not be violated, and no warrants shall issue, but upon probable cause, supported by oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized.” So why is the government trying to put both the SOPA and PIPA laws into effect? SOPA stands for Stop Online Piracy Act, which simply means if it is passed it will allow the internet to be censored, meaning any copyrighted material and any sites giving off illegal music/movies, will be terminated and “censored”. PIPA which stands for Protect Internet Protocol Act would be able to give the US government and copyright holders’ additional tools to curb access to rouge websites dedicated to infringing or counterfeiting goods. PIPA works in hand with SOPA. In 2012, these laws came into question, but the people fought to make sure it did not happen. The issue is being brought up once again. The part that is irritating to people is that the government is trying to pass these laws right under our noses. The website Wikipedia went on a “blackout” protest which shut down the website for a day. A part of the law says that: “Streaming a copy- righted work over the Internet is considered a violation of the public performance right.” This says that if a cover song and/or remake is made and if it is under a copyright, the person that made that cover or remake can be criminally charged with a misdemeanor. People have become famous from doing covers such as Ariana Grande, Justin Bieber, and many more, but imagine it being against the law to do these covers or remakes. Imagine the talent and musical masterpieces that would be missed. Celebrities such as comedian Aziz Ansari, and Trent Reznor of Nine Inch Nails are against the SOPA and PIPA acts.

Lecture 13: Introduction to iOS
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iOS is the name (as of version 4.0) of Apple’s platform for mobile applications The iPhone was released in the summer of 2007 According to Wikipedia, it has been updated 30 times since then, with the 31st update slated to occur when version 4.3 is released soon (currently in beta) iOS apps can be developed for iPhone, iPod Touch and iPad; iOS is used to run Apple TV but apps are not currently supported for that program © Kenneth M. Anderson, 2011 Tuesday, February 22, 2011 INTRODUCTION TO IOS CSCI 4448/5448: OBJECT-ORIENTED ANALYSIS & DESIGN LECTURE 13 — 02/22/2011 © Kenneth M. Anderson, 2011 Tuesday, February 22, 2011 Goals of the Lecture Present an introduction to iOS Program Coverage of the language will be INCOMPLETE We’ll see the basics… there is a lot more to learn © Kenneth M. Anderson, 2011 Tuesday, February 22, 2011 iOS 4.2 I’ll be covering iOS 4.2 which is the current “official version” Version 4.2 in November 2010 was significant in that it represented the first time that the same OS ran across all three hardware platforms Until that release iPad had been running version 3.2 which had been created specifically for that device © Kenneth M. Anderson, 2011 Tuesday, February 22, 2011

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