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- Kristensson, Per Ola, 1979-
(författare)
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Discrete and Continuous Shape Writing for Text Entry and Control
- 2007
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Mobile devices gain increasing computational power and storage capabilities, and there are already mobile phones that can show movies, act as digital music players and offer full-scale web browsing. The bottleneck for information flow is however limited by the inefficient communication channel between the user and the small device. The small mobile phone form factor has proven to be surprisingly difficult to overcome and limited text entry capabilities are in effect crippling mobile devices’ use experience. The desktop keyboard is too large for mobile phones, and the keypad too limited. In recent years, advanced mobile phones have come equipped with touch-screens that enable new text entry solutions. This dissertation explores how software keyboards on touch-screens can be improved to provide an efficient and practical text and command entry experience on mobile devices. The central hypothesis is that it is possible to combine three elements: software keyboard, language redundancy and pattern recognition, and create new effective interfaces for text entry and control. These are collectively called “shape writing” interfaces. Words form shapes on the software keyboard layout. Users write words by articulating the shapes for words on the software keyboard. Two classes of shape writing interfaces are developed and analyzed: discrete and continuous shape writing. The former recognizes users’ pen or finger tapping motion as discrete patterns on the touch-screen. The latter recognizes users’ continuous motion patterns. Experimental results show that novice users can write text with an average entry rate of 25 wpm and an error rate of 1% after 35 minutes of practice. An accelerated novice learning experiment shows that users can exactly copy a single well-practiced phrase with an average entry rate of 46.5 wpm, with individual phrase entry rate measurements up to 99 wpm. When used as a control interface, users can send commands to applications 1.6 times faster than using de-facto standard linear pull-down menus. Visual command preview leads to significantly less errors and shorter gestures for unpracticed commands. Taken together, the quantitative results show that shape writing is among the fastest mobile interfaces for text entry and control, both initially and after practice, that are currently known.
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- Kristensson, Per-Ola, 1979-
(författare)
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Large Vocabulary Shorthand Writing on Stylus Keyboard
- 2004
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- We present a novel text entry method for pen-based computers. We view the trace obtained by connecting the letter keys comprising a word on a stylus keyboard as a pattern. This pattern can be matched against a user-s pen trace, invariant of scale and translation. Hence the patterns become an efficient form of shorthand gestures, allowing users to use eyes-free openloop motor actions to perform the gestures. This can result in higher text entry speed than optimized stylus keyboards, the fastest known text entry technique for pen-computers as of today. The approach supports a gradual and seamless skill transition from novices tracing the letter keys to experts articulating the shorthand gestures. Hence the ratio between the learning effort and efficiency in using the system can be said to be optimized at any given point in time in the user-s experience with the technique. This thesis describes the rationale, architecture and lgorithms behind a stylus keyboard augmented with a high-capacity gesture recognition engine. We also report results from an Expanding Rehearsal Interval (ERI) experiment which indicates that users can acquire about 15 shorthand gestures per 45 minute training session. Empirical expert speed estimates of the technique indicate text entry speeds much higher than any prior known pen-based text entry system for mobile computers.
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- Kristensson, Per-Ola, 1979-
(författare)
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Pattern Matching on Stylus Keyboards : A Powerful Approach to Faster and Easier Pen-based Text Entry
- 2004
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Ingår i: Adjunct Proceedings of the 17th ACM Symposium on User Interface Software and Technology (UIST 2004). - New York : ACM Press. ; , s. 59-
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Konferensbidrag (refereegranskat)abstract
- Much work has been done in developing alternative methods of writing for pen-based computers, including handwriting recognition, optimization of keyboard layouts, and specialized writing systems. Generally there is a trade- off between writing speed and the effort required by the user to write the text. My doctoral dissertation is about developing text entry systems maximizing the writing speed but minimizing users' effort by taking advantage of the redundancy of the human languages and viewing the legitimate input strings in the language as patterns mapped on a keyboard layout. I present my work on using pattern matching algorithms to take advantage of these constraints to develop a shorthand writing system combined with a stylus keyboard, allowing fast text entry without the need to learn any custom alphabet or a specialized writing system. I also present some of the feedback and output interfaces I believe can greatly enhance the user experience when using pattern matching text entry systems. I conclude by discussing performance evaluation and planned future work.
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- Kristensson, Per-Ola, 1979-, et al.
(författare)
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SHARK2 : A Large Vocabulary Shorthand Writing System for Pen-based Computers
- 2004
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Ingår i: UIST '04 Proceedings of the 17th annual ACM symposium on User interface software and technology. - New York : ACM Press. - 1581139578 ; , s. 43-52
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Konferensbidrag (refereegranskat)abstract
- Zhai and Kristensson (2003) presented a method of speed-writing for pen-based computing which utilizes gesturing on a stylus keyboard for familiar words and tapping for others. In SHARK2:, we eliminated the necessity to alternate between the two modes of writing, allowing any word in a large vocabulary (e.g. 10,000-20,000 words) to be entered as a shorthand gesture. This new paradigm supports a gradual and seamless transition from visually guided tracing to recall-based gesturing. Based on the use characteristics and human performance observations, we designed and implemented the architecture, algorithms and interfaces of a high-capacity multi-channel pen-gesture recognition system. The system's key components and performance are also reported.
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- Zhai, Shumin, et al.
(författare)
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Shorthand writing on stylus keyboard
- 2003
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Ingår i: Proceeding CHI '03 Proceedings of the SIGCHI Conference on Human Factors in Computing Systems. - New York : ACM Press. ; , s. 97-104
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Konferensbidrag (refereegranskat)abstract
- We propose a method for computer-based speed writing, SHARK (shorthand aided rapid keyboarding), which augments stylus keyboarding with shorthand gesturing. SHARK defines a shorthand symbol for each word according to its movement pattern on an optimized stylus keyboard. The key principles for the SHARK design include high efficiency stemmed from layout optimization, duality of gesturing and stylus tapping, scale and location independent writing, Zipf's law, and skill transfer from tapping to shorthand writing due to pattern consistency. We developed a SHARK system based on a classic handwriting recognition algorithm. A user study demonstrated the feasibility of the SHARK method.
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