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Title: Performance Optimizations of Virtual Keyboards for Stroke-Based Text Entry on a Touch-Based TabletopAuthor: Jochen Rick
Presentation: Department of Computing. The Open University. Milton Keynes, MK7 6AA, UK
Summary: In this article, Rick discusses his studies about enhancing and optimizing the performance of text entry on tabletops. He explains that even though a physical keyboard could be attached to such a device, it is impractical, it defeats the purpose of the interaction between the user and the tabletop. According to him, not much research has been done in this area, and his goal is to find a viable technique that will enhance the use of shape writing - stoking through all the letters in a word on a virtual keyboard - and how this technique is affected by using different keyboard layouts.
Rick provides some background about the history of keyboard layouts, how the QWERTY layout came about, and why it has stayed as the most popular and standardized keyboard layout internationally. As he discusses each of the layouts, he starts analyzing how stoke based entry text would work in such a layout. Much of the work that has been done in this area has been based on Fitt's Law. Rick implements a user study to investigate the role of distance and angle for a sequence of stokes. With the information revealed in this study, he is able to create a mathematical model. He then is able to apply this model, and in order to recognize a word from the sequence of strokes, he uses the list of 40,000 most popular words in the English, Project Gutenberg.The basis of his model were a three step stroke, a Beginning, Middle and End as it is shown in the picture below and it was based in calculations regarding distance and angle of the strokes.
He then evaluated his technique and how it performed when using it with different keyboard layouts. He finds that this technique has a gain in performance of 17.3% when used with the QWERTY layout, however there was a 29.5% gain in performance if using the OPTI II layout - much faster than QWERTY.
Discussion: I have heard of this kind of application before, but I have never tried it myself. Hopefully my next phone will have such an application. Even though I am so used to the QWERTY layout for both my computers and my phone, I think it would be interesting to use a different layout for a shape writing application. I think there can be a better mapping of words created specially for shape writing. Maybe one where the vowels are placed in convenient places, also where two letters that are not often used together are not placed together. As Rick explains, the QWERTY layout was first originated by placing letters that were often used one after the other in separate places to avoid mechanical problems. Now in this application it would be way more useful if those letters were placed next to each other, instead of in the opposite extremes of the layout. From a user's point of view, I would prefer something that look like the Hexagon OSK layout.
When I finally upgrade my phone, I'd love to try this kind of thing out. That keyboard layout seems pretty cool too and a good use for this. Lots of common articles and other words have the letters really close to each other.
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