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In mobile browsers, you need to be especially careful about using timers because of the battery consumption. If you need to use many high-frequency timers at the same time, try to manage them using only one timer that will launch different behaviors from the same process.

The first question we need to ask ourselves is, what happens when our web page goes to the background because the user switches focus to another application (in multitasking operating systems) or opens or browses to another tab or window? Another problem is what happens when the phone goes to sleep (because of the user’s inactivity while the script is executing). The behavior of timers can be a little tricky in these situations.Yet another problem is that timers execute on the same thread as the main script. If our script is taking too much processor time (a normal situation with large scripts on low- and mid-end devices), our timers will be delayed until some spare execution time is found.If we use a low frequency for the timer (for example, 10 milliseconds), the timer will generally have problems meeting the timetable.Remember that the JavaScript execution time depends a lot on the device hardware and the browser’s engine. Even if they’re running the same operating system, like Android, execution times can differ: for example, an HTC G1 will be much slower than a Nexus One with a 1-Ghz processor.

As shown in Figure 4, the real times are very different on different devices. On low- and mid-end devices, if they work at all, the result is far from our 200 ms intention—some low-end devices don’t even accept timers with a frequency of less than 1 second.

While edX shares the common theme of scaling the online experience to very large groups, it adds an important component lacking from the various Stanford spin-offs, namely research.

EdX partners will be doing more than putting content online, they will be studying how people learn in these environments in an effort to improve both classroom and online learning.

Leaving purely technical considerations aside (in some cases the final result is better than in others), the general quality of those magazines is without doubt extremely high and the integration between classic and multimedia content makes their reading experience very pleasant and engaging. But there is a basic limitation that could play a significant role in preventing their widespread diffusion, thereby making them not competitive in terms of economic return. The problem is not the limited number of iPads in circulation, as some may think, but the difficulty – or the inability – to download single issues of a certain magazines on your device because of their excessive size, which usually is around 400 MB.

the general quality of those magazines is without doubt extremely high and the integration between classic and multimedia content makes their reading experience very pleasant and engaging. But there is a basic limitation that could play a significant role in preventing their widespread diffusion, thereby making them not competitive in terms of economic return. The problem is not the limited number of iPads in circulation, as some may think, but the difficulty – or the inability – to download single issues of a certain magazines on your device because of their excessive size, which usually is around 400 MB.

each download may take a period ranging from twenty to seventy minutes if you are connected to a wi-fi hotspot. If you use a 3G connection, instead, the download is inhibited and a message warns you that, due to the excessive size of the file, you must be connected to a wi-fi to continue to the download. Apart from the frustration generated by waiting too long for the completion of the download (especially if you consider that there are an infinite number of alternative sources of information available in a few seconds, for free, just surfing the web), when the user doesn’t have access to a wi-fi network, he is likely to quit the purchase altogether

The iPad has a bigger screen, and so it has a bigger resolution. With the iPhone 4, however, Apple did something different: they increased the resolution without changing the physical size of the screen. This makes for a higher pixel density, pixels are smaller and more tightly packed. In one square inch of the iPhone 4’s screen there are around 106 thousand pixels (at 326 PPI, or Pixels per Inch), while the older models have only about 26 thousand (at 163 PPI) in an inch – 4 times less! This makes graphics on the screen seem like continuous lines, because your eye can’t see the individual pixels. Apple calls this technology the “Retina Display” because they claim the human eye (the retina) can’t physically see the pixels at this resolution.

Using Two Images The official way of adding high-resolution support to your application is by having two versions of each image, one in “regular” resolution and one in double resolution. Whenever your application is viewed on the Retina Display, the larger image will be loaded automatically. This method allows for full and precise control of how your application will look in each case, and is very easy to apply to your existing applications. The full size image file should be named however you want, such as “Button.png”. Use this image name in your code and Interface Builder wherever you want to reference the image. The double-size image should be twice the size of its matching smaller image and named exactly the same with “@2x” appended to the name. In our example, we would name it “Button@2x.png”. Unfortunately, this technique will not work on the iPad; a pixel-doubled application will not load the higher resolution resource. This will probably be addressed in the future iOS 4 update which is scheduled to come to iPad this fall.

According to the Google blog, the game is built using “HTML5 features such as WebSockets for real-time gaming synchronicity on desktop and mobile, and Canvas and CSS3 for rich and engaging visuals

Find What You Actually Want to Learn About First things first, you need to figure out what you're actually interested in.

Figure Out How You Learn Best Full sizeWe all learn a little differently, and while we're fans of learning by doing, you can't always do that with everything.

Learn By Doing Whenever Possible Full sizeIn most cases you're going to learn best by doing. That means practicing programming by actually making a program or learning a new language by speaking it. If you're having trouble getting over the learning hump and sticking with it, you might simply need to provide better context for the process.

Listen, create and share FREE geolocalized audioguides.

Sharp, HTC and perhaps Apple are set to launch 3D smart-phones in the near future, and now it seems Research In Motion (RIM) have put plans in place for its BlackBerries to feature a tridimensional display

all new videos uploaded to YouTube are now transcoded into WebM. WebM is an open media file format for video and audio on the web. Its openness allows anyone to improve the format and its integrations, resulting in a better experience for you in the long-term.

ZoomIt is screen zoom and annotation tool for technical presentations that include application demonstrations. ZoomIt runs unobtrusively in the tray and activates with customizable hotkeys to zoom in on an area of the screen, move around while zoomed, and draw on the zoomed image. I wrote ZoomIt to fit my specific needs and use it in all my presentations.ZoomIt works on all versions of Windows and you can use pen input for ZoomIt drawing on tablet PCs

With the continued penetration of smartphones into the mainstream market, QR codes are becoming more of an option for designers to prompt interaction. The two-dimensional barcode can easily be generated from text, including a website link, and printed on materials in magazines and conferences. An artist in Paris found an unusual use for the black-and-white squares: to animate a tattoo.

According to a FAQ on Picasa's support site, the photo-sharing service provides up to 1 GB of free storage for photos and videos to its users. But since Google+ actively encourages storing and sharing photos - its Android app even offers an "instant upload" option - there may have been some concern about storage limits among Picasa users. As it turns out, there's nothing to worry about. If you're signed up for Google+, photos up to 2048x2048 pixels and videos up to 15 minutes long won't count towards this free storage limit. And Google will automatically resize photos for you when you upload them to Google+, so they stay under the free size limit. That means only photos uploaded directly to Picasa Web Albums over the 2048x2048 size will count towards the 1 GB of free storage, explains Google. And when that limit is reached, photos will be automatically resized. Meanwhile, for non-Google+ users, there are slightly stricter rules: photos up to 800x800 and videos up to 15 minutes won't count towards free storage. Again, when the 1 GB limit is reached, larger photos will be resized down. Simply put, this means that whether you're on Google+ or not, Picasa offers unlimited free storage for photos and videos (under 15 minutes). The difference is that Google+ users can upload higher resolution photos to Plus/Picasa without being penalized.

A pair of MIT Media Lab alums have come up with a do-it-yourself kit for making smart environments. David Carr and John Kestner, partners in the industrial design firm Supermechanical, have developed a small, durable, inexpensive remote sensor node, and an easy-to-use web app that turns data from the sensor node into timely information. The system, dubbed Twine, lets you tie everyday objects into your digital life.

Twine is a palm-size block of rubber that contains a WiFi node, temperature sensor and accelerometer. It’s powered by two AAA batteries or a mini USB connection. And it has a port where external sensors can connect. The initial external sensors are a magnetic switch, moisture sensor and a breakout board for building your own sensor. Supermechanical is also considering an RFID reader, pressure sensor and current sensor.