Jacob O. Wobbrock
Has also published under the name of:
"Jacob Wobbrock"
Personal Homepage:
faculty.washington.edu/wobbrock/Current place of employment:
University of WashingtonJacob O. Wobbrock is a professor in The Information School at the University of Washington. He also holds an adjunct appointment in Computer Science and Engineering. His research interests are input techniques, interaction design, human performance with computing systems, assistive technology, universal design, mobile user interfaces, and other areas of human-computer interaction (HCI). He received his Ph.D. from the Human-Computer Interaction Institute in the School of Computer Science at Carnegie Mellon University in 2006.
Publications by Jacob O. Wobbrock (bibliography)
» 2009 «
Harada, Susumu, Wobbrock, Jacob O., Malkin, Jonathan, Bilmes, Jeff A. and Landay, James A. (2009): Longitudinal study of people learning to use continuous voice-based cursor control. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 347-356. Available online
“We conducted a 2.5 week longitudinal study with five motor impaired (MI) and four non-impaired (NMI) participants, in which they learned to use the Vocal Joystick, a voice-based user interface control system. We found that the participants were able to learn the mapping between the vowel sounds and directions used by the Vocal Joystick, and showed marked improvement in their target acquisition performance. At the end of the ten session period, the NMI group reached the same level of performance as the previously measured "expert" Vocal Joystick performance, and the MI group was able to reach 70% of that level. Two of the MI participants were also able to approach the performance of their preferred device, a touchpad. We report on a number of issues that can inform the development of further enhancements in the realm of voice-driven computer control.”
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Wobbrock, Jacob O., Morris, Meredith Ringel and Wilson, Andrew D. (2009): User-defined gestures for surface computing. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 1083-1092. Available online
“Many surface computing prototypes have employed gestures created by system designers. Although such gestures are appropriate for early investigations, they are not necessarily reflective of user behavior. We present an approach to designing tabletop gestures that relies on eliciting gestures from non-technical users by first portraying the effect of a gesture, and then asking users to perform its cause. In all, 1080 gestures from 20 participants were logged, analyzed, and paired with think-aloud data for 27 commands performed with 1 and 2 hands. Our findings indicate that users rarely care about the number of fingers they employ, that one hand is preferred to two, that desktop idioms strongly influence users' mental models, and that some commands elicit little gestural agreement, suggesting the need for on-screen widgets. We also present a complete user-defined gesture set, quantitative agreement scores, implications for surface technology, and a taxonomy of surface gestures. Our results will help designers create better gesture sets informed by user behavior.”
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Wobbrock, Jacob O., Fogarty, James, Liu, Shih-Yen (Sean), Kimuro, Shunichi and Harada, Susumu (2009): The angle mouse: target-agnostic dynamic gain adjustment based on angular deviation. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 1401-1410. Available online
“We present a novel method of dynamic C-D gain adaptation that improves target acquisition for users with motor impairments. Our method, called the Angle Mouse, adjusts the mouse C-D gain based on the deviation of angles sampled during movement. When angular deviation is low, the gain is kept high. When angular deviation is high, the gain is dropped, making the target bigger in motor-space. A key feature of the Angle Mouse is that, unlike most pointing facilitation techniques, it is target-agnostic, requiring no knowledge of target locations or dimensions. This means that the problem of distractor targets is avoided because adaptation is based solely on the user's behavior. In a study of 16 people, 8 of which had motor impairments, we found that the Angle Mouse improved motor-impaired pointing throughput by 10.3% over the Windows default mouse and 11.0% over sticky icons. For able-bodied users, there was no significant difference among the three techniques, as Angle Mouse throughput was within 1.2% of the default. Thus, the Angle Mouse improved pointing performance for users with motor impairments while remaining unobtrusive for able-bodied users.”
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Choe, Eun Kyoung, Shinohara, Kristen, Chilana, Parmit K., Dixon, Morgan and Wobbrock, Jacob O. (2009): Exploring the design of accessible goal crossing desktop widgets. In: Proceedings of ACM CHI 2009 Conference on Human Factors in Computing Systems 2009. pp. 3733-3738. Available online
“Prior work has shown that goal crossing may be a more accessible interaction technique than conventional pointing-and-clicking for motor-impaired users. Although goal crossing with pen-based input devices has been studied, pen-based designs have limited applicability on the desktop because the pen can "fly in," cross, and "fly out," whereas a persistent mouse cursor cannot. We therefore explore possible designs for accessible mouse-based goal crossing widgets that avoid triggering unwanted goals by using secondary goals, gestures, and corners and edges. We identify four design principles for accessible desktop goal crossing widgets: ease of use for motor-impaired users, safety from false selections, efficiency, and scalability.”
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» 2008 «
Gajos, Krzysztof Z., Wobbrock, Jacob O. and Weld, Daniel S. (2008): Improving the performance of motor-impaired users with automatically-generated, ability-based interfaces. In: Proceedings of ACM CHI 2008 Conference on Human Factors in Computing Systems April 5-10, 2008. pp. 1257-1266. Available online
“We evaluate two systems for automatically generating personalized interfaces adapted to the individual motor capabilities of users with motor impairments. The first system, SUPPLE, adapts to users' capabilities indirectly by first using the ARNAULD preference elicitation engine to model a user's preferences regarding how he or she likes the interfaces to be created. The second system, SUPPLE++, models a user's motor abilities directly from a set of one-time motor performance tests. In a study comparing these approaches to baseline interfaces, participants with motor impairments were 26.4% faster using ability-based user interfaces generated by SUPPLE++. They also made 73% fewer errors, strongly preferred those interfaces to the manufacturers' defaults, and found them more efficient, easier to use, and much less physically tiring. These findings indicate that rather than requiring some users with motor impairments to adapt themselves to software using separate assistive technologies, software can now adapt itself to the capabilities of its users.”
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Wobbrock, Jacob O., Cutrell, Edward, Harada, Susumu and MacKenzie, I. Scott (2008): An error model for pointing based on Fitts' law. In: Proceedings of ACM CHI 2008 Conference on Human Factors in Computing Systems April 5-10, 2008. pp. 1613-1622. Available online
“For decades, Fitts' law (1954) has been used to model pointing time in user interfaces. As with any rapid motor act, faster pointing movements result in increased errors. But although prior work has examined accuracy as the "spread of hits," no work has formulated a predictive model for error rates (0-100%) based on Fitts' law parameters. We show that Fitts' law mathematically implies a predictive error rate model, which we derive. We then describe an experiment in which target size, target distance, and movement time are manipulated. Our results show a strong model fit: a regression analysis of observed vs. predicted error rates yields a correlation of R{sup:2}=.959 for N=90 points. Furthermore, we show that the effect on error rate of target size (W) is greater than that of target distance (A), indicating a departure from Fitts' law, which maintains that W and A contribute proportionally to index of difficulty (ID). Our error model can be used with Fitts' law to estimate and predict error rates along with speeds, providing a framework for unifying this dichotomy.”
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Kane, Shaun K., Bigham, Jeffrey P. and Wobbrock, Jacob O. (2008): Slide rule: making mobile touch screens accessible to blind people using multi-touch interaction techniques. In: Tenth Annual ACM SIGACCESS Conference on Assistive Technologies 2008. pp. 73-80. Available online
“Recent advances in touch screen technology have increased the prevalence of touch screens and have prompted a wave of new touch screen-based devices. However, touch screens are still largely inaccessible to blind users, who must adopt error-prone compensatory strategies to use them or find accessible alternatives. This inaccessibility is due to interaction techniques that require the user to visually locate objects on the screen. To address this problem, we introduce Slide Rule, a set of audio-based multi-touch interaction techniques that enable blind users to access touch screen applications. We describe the design of Slide Rule, our interaction techniques, and a user study in which 10 blind people used Slide Rule and a button-based Pocket PC screen reader. Results show that Slide Rule was significantly faster than the button-based system, and was preferred by 7 of 10 users. However, users made more errors when using Slide Rule than when using the more familiar button-based system.”
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Kane, Shaun K., Wobbrock, Jacob O., Harniss, Mark and Johnson, Kurt L. (2008): TrueKeys: identifying and correcting typing errors for people with motor impairments. In: Proceedings of the 2008 International Conference on Intelligent User Interfaces 2008. pp. 349-352. Available online
“People with motor impairments often have difficulty typing using desktop keyboards. We developed TrueKeys, a system that combines models of word frequency, keyboard layout, and typing error patterns to automatically identify and correct typing mistakes. In this paper, we describe the TrueKeys algorithm, compare its performance to existing correction algorithms, and report on a study of TrueKeys with 9 motor-impaired and 9 non-impaired participants. Running in non-interactive mode, TrueKeys performed more corrections than popular commercial and open source spell checkers. Used interactively, both motor-impaired and non-impaired users performed typing tasks significantly more accurately with TrueKeys than without. However, typing speed was reduced while TrueKeys was enabled.”
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Kane, Shaun K., Wobbrock, Jacob O. and Smith, Ian E. (2008): Getting off the treadmill: evaluating walking user interfaces for mobile devices in public spaces. In: Hofte, G. Henri ter, Mulder, Ingrid and Ruyter, Boris E. R. de (eds.) Proceedings of the 10th Conference on Human-Computer Interaction with Mobile Devices and Services - Mobile HCI 2008 September 2-5, 2008, Amsterdam, the Netherlands. pp. 109-118. Available online
Harada, Susumu, Lester, Jonathan, Patel, Kayur, Saponas, T. Scott, Fogarty, James, Landay, James A. and Wobbrock, Jacob O. (2008): VoiceLabel: using speech to label mobile sensor data. In: Digalakis, Vassilios, Potamianos, Alexandros, Turk, Matthew, Pieraccini, Roberto and Ivanov, Yuri (eds.) Proceedings of the 10th International Conference on Multimodal Interfaces - ICMI 2008 October 20-22, 2008, Chania, Crete, Greece. pp. 69-76. Available online
Wobbrock, Jacob O., Rubinstein, James, Sawyer, Michael W. and Duchowski, Andrew T. (2008): Longitudinal evaluation of discrete consecutive gaze gestures for text entry. In: Räihä, Kari-Jouko and Duchowski, Andrew T. (eds.) ETRA 2008 - Proceedings of the Eye Tracking Research and Application Symposium March 26-28, 2008, Savannah, Georgia, USA. pp. 11-18. Available online
Wobbrock, Jacob O. and Gajos, Krzysztof Z. (2008): Goal Crossing with Mice and Trackballs for People with Motor Impairments: Performance, Submovements, and Design Directions. In ACM Transactions on Accessible Computing, 1 (1) p. 4
“Prior research shows that people with motor impairments face considerable challenges when using conventional mice and trackballs. One challenge is positioning the mouse cursor within confined target areas; another is executing a precise click without slipping. These problems can make mouse pointing in graphical user interfaces very difficult for some people. This article explores goal crossing as an alternative strategy for more accessible target acquisition. In goal crossing, targets are boundaries that are simply crossed by the mouse cursor. Thus, goal crossing avoids the two aforementioned problems. To date, however, researchers have not examined the feasibility of goal crossing for people with motor difficulties. We therefore present a study comparing area pointing and goal crossing. Our performance results indicate that although Fitts' throughput for able-bodied users is higher for area pointing than for goal crossing (4.72 vs. 3.61 bits/s), the opposite is true for users with motor impairments (2.34 vs. 2.88 bits/s). However, error rates are higher for goal crossing than for area pointing under a strict definition of crossing errors (6.23% vs. 1.94%). We also present path analyses and an examination of submovement velocity, acceleration, and jerk (the change in acceleration over time). These results show marked differences between crossing and pointing and almost categorically favor crossing. An important finding is that crossing reduces jerk for both participant groups, indicating more fluid, stable motion. To help realize the potential of goal crossing for computer access, we offer design concepts for crossing widgets that address the occlusion problem, which occurs when one crossing goal obscures another in persistent mouse-cursor interfaces. This work provides the motivation and initial steps for further exploration of goal crossing on the desktop, and may help researchers and designers to radically reshape user interfaces to provide accessible goal crossing, thereby lowering barriers to access.”
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Wobbrock, Jacob O., Myers, Brad A. and Aung, Htet Htet (2008): The performance of hand postures in front- and back-of-device interaction for mobile computing. In International Journal of Human-Computer Studies, 20 (12) pp. 857-875
“Three studies of different mobile-device hand postures are presented. The first study measures the performance of postures in Fitts' law tasks using one and two hands, thumbs and index fingers, horizontal and vertical movements, and front- and back-of-device interaction. Results indicate that the index finger performs well on both the front and the back of the device, and that thumb performance on the front of the device is generally worse. Fitts' law models are created and serve as a basis for comparisons. The second study examines the orientation of shapes on the front and back of a mobile device. It shows that participants' expectations of visual feedback for finger movements on the back of a device reverse the direction of their finger movements to favor a "transparent device" orientation. The third study examines letter-like gestures made on the front and back of a device. It confirms the performance of the index finger on the front of the device, while showing limitations in the ability for the index finger on the back to perform complex gestures. Taken together, these results provide an empirical foundation upon which new mobile interaction designs can be based. A set of design implications and recommendations are given based directly on the findings presented.”
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» 2007 «
Wobbrock, Jacob O., Chau, Duen Horng and Myers, Brad A. (2007): An alternative to push, press, and tap-tap-tap: gesturing on an isometric joystick for mobile phone text entry. In: Proceedings of ACM CHI 2007 Conference on Human Factors in Computing Systems 2007. pp. 667-676. Available online
“A gestural text entry method for mobile is presented. Unlike most mobile phone text entry methods, which rely on repeatedly pressing buttons, our gestural method uses an isometric joystick and the EdgeWrite alphabet to allow users to write by making letter-like "pressure strokes." In a 15-session study comparing character-level EdgeWrite to Multitap, subjects' speeds were statistically indistinguishable, reaching about 10 WPM. In a second 15-session study comparing word-level EdgeWrite to T9, the same subjects were again statistically indistinguishable, reaching about 16 WPM. Uncorrected errors were low, around 1% or less for each method. In addition, subjective results favored EdgeWrite. Overall, results indicate that our isometric joystick-based method is highly competitive with two commercial keypad-based methods, opening the way for keypad-less designs and text entry on tiny devices. Additional results showed that a joystick on the back could be used at about 70% of the speed of the front, and the front joystick could be used eyes-free at about 80% of the speed of normal use.”
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González, Iván E., Wobbrock, Jacob O., Chau, Duen Horng, Faulring, Andrew and Myers, Brad A. (2007): Eyes on the road, hands on the wheel: thumb-based interaction techniques for input on steering wheels. In: Proceedings of the 2007 Conference on Graphics Interface 2007. pp. 95-102. Available online
“The increasing quantity and complexity of in-vehicle systems creates a demand for user interfaces which are suited to driving. The steering wheel is a common location for the placement of buttons to control navigation, entertainment, and environmental systems, but what about a small touchpad? To investigate this question, we embedded a Synaptics StampPad in a computer game steering wheel and evaluated seven methods for selecting from a list of over 3000 street names. Selection speed was measured while stationary and while driving a simulator. Results show that the EdgeWrite gestural text entry method is about 20% to 50% faster than selection-based text entry or direct list-selection methods. They also show that methods with slower selection speeds generally resulted in faster driving speeds. However, with EdgeWrite, participants were able to maintain their speed and avoid incidents while selecting and driving at the same time. Although an obvious choice for constrained input, on-screen keyboards generally performed quite poorly.”
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Wobbrock, Jacob O. and Gajos, Krzysztof Z. (2007): A comparison of area pointing and goal crossing for people with and without motor impairments. In: Ninth Annual ACM Conference on Assistive Technologies 2007. pp. 3-10. Available online
“Prior work has highlighted the challenges faced by people with motor impairments when trying to acquire on-screen targets using a mouse or trackball. Two reasons for this are the difficulty of positioning the mouse cursor within a confined area, and the challenge of accurately executing a click. We hypothesize that both of these difficulties with area pointing may be alleviated in a different target acquisition paradigm called "goal crossing." In goal crossing, users do not acquire a confined area, but instead pass over a target line. Although goal crossing has been studied for able-bodied users, its suitability for people with motor impairments is unknown. We present a study of 16 people, 8 of whom had motor impairments, using mice and trackballs to do area pointing and goal crossing. Our results indicate that Fitts' law models both techniques for both user groups. Furthermore, although throughput for able-bodied users was higher for area pointing than for goal crossing (4.72 vs. 3.61 bits/s), the opposite was true for users with motor impairments (2.34 vs. 2.88 bits/s), suggesting that goal crossing may be viable for them. However, error rates were higher for goal crossing than for area pointing under a strict definition of crossing errors (6.23% vs. 1.94%). Subjective results indicate a preference for goal crossing among motor-impaired users. This work provides the empirical foundation from which to pursue the design of crossing-based interfaces as accessible alternatives to pointing-based interfaces.”
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Froehlich, Jon, Wobbrock, Jacob O. and Kane, Shaun K. (2007): Barrier pointing: using physical ed. In: Ninth Annual ACM Conference on Assistive Technologies 2007. pp. 19-26. Available online
“Mobile phones and personal digital assistants (PDAs) are incredibly popular pervasive technologies. Many of these devices contain touch screens, which can present problems for users with motor impairments due to small targets and their reliance on tapping for target acquisition. In order to select a target, users must tap on the screen, an action which requires the precise motion of flying into a target and lifting without slipping. In this paper, we propose a new technique for target acquisition called barrier pointing, which leverages the elevated physical edges surrounding the screen to improve pointing accuracy. After designing a series of barrier pointing techniques, we conducted an initial study with 9 able bodied users and 9 users with motor impairments in order to discover the parameters that make barrier pointing successful. From this data, we offer an in-depth analysis of the performance of two motor impaired users for whom barrier pointing was especially beneficial. We show the importance of providing physical stability by allowing the stylus to press against the screen and its physical edge. We offer other design insights and lessons learned that can inform future attempts at leveraging the physical properties of mobile devices to improve accessibility.”
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Harada, Susumu, Wobbrock, Jacob O. and Landay, James A. (2007): Voicedraw: a hands-free voice-driven drawing application for people with motor impairments. In: Ninth Annual ACM Conference on Assistive Technologies 2007. pp. 27-34. Available online
“We present VoiceDraw, a voice-driven drawing application for people with motor impairments that provides a way to generate free-form drawings without needing manual interaction. VoiceDraw was designed and built to investigate the potential of the human voice as a modality to bring fluid, continuous direct manipulation interaction to users who lack the use of their hands. VoiceDraw also allows us to study the issues surrounding the design of a user interface optimized for non-speech voice-based interaction. We describe the features of the VoiceDraw application, our design process, including our user-centered design sessions with a 'voice painter', and offer lessons learned that could inform future voice-based design efforts. In particular, we offer insights for mapping human voice to continuous control.”
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Bigham, Jeffrey P., Cavender, Anna C., Brudvik, Jeremy T., Wobbrock, Jacob O. and Lander, Richard E. (2007): WebinSitu: a comparative analysis of blind and sighted browsing behavior. In: Ninth Annual ACM Conference on Assistive Technologies 2007. pp. 51-58. Available online
“Web browsing is inefficient for blind web users because of persistent accessibility problems, but the extent of these problems and their practical effects from the perspective of the user has not been sufficiently examined. We conducted a study in situ to investigate the accessibility of the web as experienced by web users. This remote study used an advanced web proxy that leverages AJAX technology to record both the pages viewed and the actions taken by users on the web pages that they visited. Our study was conducted remotely over the period of one week, and our participants used the assistive technology and software to which they were already accustomed and had already configured according to preference. These advantages allowed us to aggregate observations of many users and to explore the practical effects on and coping strategies employed by our blind participants. Our study reflects web accessibility from the perspective of web users and describes quantitative differences in the browsing behavior of blind and sighted web users.”
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Wobbrock, Jacob O., Wilson, Andrew D. and Li, Yang (2007): Gestures without libraries, toolkits or training: a $1 recognizer for user interface prototypes. In: Proceedings of the ACM Symposium on User Interface Software and Technology October 7-10, 2007, Newport, Rhode Island, USA. pp. 159-168. Available online
“Although mobile, tablet, large display, and tabletop computers increasingly present opportunities for using pen, finger, and wand gestures in user interfaces, implementing gesture recognition largely has been the privilege of pattern matching experts, not user interface prototypers. Although some user interface libraries and toolkits offer gesture recognizers, such infrastructure is often unavailable in design-oriented environments like Flash, scripting environments like JavaScript, or brand new off-desktop prototyping environments. To enable novice programmers to incorporate gestures into their UI prototypes, we present a "$1 recognizer" that is easy, cheap, and usable almost anywhere in about 100 lines of code. In a study comparing our $1 recognizer, Dynamic Time Warping, and the Rubine classifier on user-supplied gestures, we found that $1 obtains over 97% accuracy with only 1 loaded template and 99% accuracy with 3+ loaded templates. These results were nearly identical to DTW and superior to Rubine. In addition, we found that medium-speed gestures, in which users balanced speed and accuracy, were recognized better than slow or fast gestures for all three recognizers. We also discuss the effect that the number of templates or training examples has on recognition, the score falloff along recognizers' N-best lists, and results for individual gestures. We include detailed pseudocode of the $1 recognizer to aid development, inspection, extension, and testing.”
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Gajos, Krzysztof Z., Wobbrock, Jacob O. and Weld, Daniel S. (2007): Automatically generating user interfaces adapted to users' motor and vision capabilities. In: Proceedings of the ACM Symposium on User Interface Software and Technology October 7-10, 2007, Newport, Rhode Island, USA. pp. 231-240. Available online
“Most of today's GUIs are designed for the typical, able-bodied user; atypical users are, for the most part, left to adapt as best they can, perhaps using specialized assistive technologies as an aid. In this paper, we present an alternative approach: SUPPLE++ automatically generates interfaces which are tailored to an individual's motor capabilities and can be easily adjusted to accommodate varying vision capabilities. SUPPLE++ models users. motor capabilities based on a onetime motor performance test and uses this model in an optimization process, generating a personalized interface. A preliminary study indicates that while there is still room for improvement, SUPPLE++ allowed one user to complete tasks that she could not perform using a standard interface, while for the remaining users it resulted in an average time savings”
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» 2006 «
Wobbrock, Jacob O. and Myers, Brad A. (2006): Trackball text entry for people with motor impairments. In: Proceedings of ACM CHI 2006 Conference on Human Factors in Computing Systems 2006. pp. 479-488. Available online
“We present a new gestural text entry method for trackballs. The method uses the mouse cursor and relies on crossing instead of pointing. A user writes in fluid Roman-like unistrokes by ""pulsing"" the trackball in desired letter patterns. We examine this method both theoretically using the Steering Law and empirically in two studies. Our studies show that able-bodied users who were unfamiliar with trackballs could write at about 10 wpm with <4% total errors after 45 minutes. In eight sessions, a motor-impaired trackball user peaked at 7.11 wpm with 0% uncorrected errors, compared to 5.95 wpm with 0% uncorrected errors with an on-screen keyboard. Over sessions, his speeds were significantly faster with our gestural method than with an on-screen keyboard. A former 15-year veteran of on-screen keyboards, he now uses our gestural method instead.”
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Wobbrock, Jacob O., Myers, Brad A. and Rothrock, Brandon (2006): Few-key text entry revisited: mnemonic gestures on four keys. In: Proceedings of ACM CHI 2006 Conference on Human Factors in Computing Systems 2006. pp. 489-492. Available online
“We present a new 4-key text entry method that, unlike most few-key methods, is gestural instead of selection-based. Importantly, its gestures mimic the writing of Roman letters for high learnability. We compare this new 4-key method to predominant 3-key and 5-key methods theoretically using KSPC and empirically using a longitudinal study of 5 subjects over 10 sessions. The study includes an evaluation of the 4-key method without any on-screen visualization-an impossible condition for the selection-based methods. Our results show that the new 4-key method is quickly learned, becoming faster than the 3-key and 5-key methods after just 10 minutes of writing, although it produces more errors. Interestingly, removing a visualization of the gestures being made causes no detriment to the 4-key method, which is an advantage for eyes-free text entry.”
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Wobbrock, Jacob O. and Myers, Brad A. (2006): From letters to words: efficient stroke-based word completion for trackball text entry. In: Eighth Annual ACM Conference on Assistive Technologies 2006. pp. 2-9. Available online
“We present a major extension to our previous work on Trackball EdgeWrite -- a unistroke text entry method for trackballs -- by taking it from a character-level technique to a word-level one. Our design is called stroke-based word completion, and it enables efficient word selection as part of the stroke-making process. Unlike most word completion designs, which require users to select words from a list, our technique allows users to select words by performing a fluid crossing gesture. Our theoretical model shows this word-level design to be 45.0% faster than our prior model for character-only strokes. A study with a subject with spinal cord injury comparing Trackball EdgeWrite to the onscreen keyboard WiViK, both using word prediction and completion, shows that Trackball EdgeWrite is competitive with WiViK in speed (12.09 vs. 11.82 WPM) and accuracy (3.95% vs. 2.21% total errors), but less visually tedious and ultimately preferred. The results also show that word-level Trackball EdgeWrite is 46.5% faster and 36.7% more accurate than our subject's prior peak performance with character-level Trackball EdgeWrite, and 75.2% faster and 40.2% more accurate than his prior peak performance with his preferred on-screen keyboard. An additional evaluation of the same subject over a two-month field deployment shows a 43.9% reduction in unistrokes due to strokebased word completion in Trackball EdgeWrite.”
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Wobbrock, Jacob O. and Myers, Brad A. (2006): Analyzing the input stream for character-level errors in unconstrained text entry evaluations. In ACM Transactions on Computer-Human Interaction, 13 (4) pp. 458-489
“Recent improvements in text entry error rate measurement have enabled the running of text entry experiments in which subjects are free to correct errors (or not) as they transcribe a presented string. In these "unconstrained" experiments, it is no longer necessary to force subjects to unnaturally maintain synchronicity with presented text for the sake of performing overall error rate calculations. However, the calculation of character-level error rates, which can be trivial in artificially constrained evaluations, is far more complicated in unconstrained text entry evaluations because it is difficult to infer a subject's intention at every character. For this reason, prior character-level error analyses for unconstrained experiments have only compared presented and transcribed strings, not input streams. But input streams are rich sources of character-level error information, since they contain all of the text entered (and erased) by a subject. The current work presents an algorithm for the automated analysis of character-level errors in input streams for unconstrained text entry evaluations. It also presents new character-level metrics that can aid method designers in refining text entry methods. To exercise these metrics, we perform two analyses on data from an actual text entry experiment. One analysis, available from the prior work, uses only presented and transcribed strings. The other analysis uses input streams, as described in the current work. The results confirm that input stream error analysis yields richer information for the same empirical data. To facilitate the use of these new analyses, we offer pseudocode and downloadable software for performing unconstrained text entry experiments and analyzing data.”
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Wobbrock, Jacob O., Myers, Brad A. and Chau, Duen Horng (2006): In-stroke word completion. In: Proceedings of the ACM Symposium on User Interface Software and Technology 2006. pp. 333-336. Available online
“We present the design and implementation of a word-level stroking system called Fisch, which is intended to improve the speed of character-level unistrokes. Importantly, Fisch does not alter the way in which character-level unistrokes are made, but allows users to gradually ramp up to word-level unistrokes by extending their letters in minimal ways. Fisch relies on in-stroke word completion, a flexible design for fluidly turning unistroke letters into whole words. Fisch can be memorized at the motor level since word completions always appear at the same positions relative to the strokes being made. Our design for Fisch is suitable for use with any unistroke alphabet. We have implemented Fisch for multiple versions of EdgeWrite, and results show that Fisch reduces the number of strokes during entry by 43.9% while increasing the rate of entry. An informal test of "record speed" with the stylus version resulted in 50-60 wpm with no uncorrected errors.”
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» 2005 «
Wobbrock, Jacob O. and Myers, Brad A. (2005): Gestural text entry on multiple devices. In: Seventh Annual ACM Conference on Assistive Technologies 2005. pp. 184-185. Available online
“We present various adaptations of the EdgeWrite unistroke text entry method that work on multiple computer input devices: styluses, touchpads, displacement and isometric joysticks, four keys or buttons, and trackballs. We argue that consistent, flexible, multi-device input is important to both accessibility and to ubiquitous computing. For accessibility, multi-device input means users can switch among devices, distributing strain and fatigue among different muscle groups. For ubiquity, it means users can "learn once, write anywhere," even as new devices emerge. By considering the accessibility and ubiquity of input techniques, we can design for both motor-impaired users and "situationally impaired" able-bodied users who are on-the-go. We discuss the requirements for such input and the challenges of multi-device text entry, such as solving the segmentation problem. This paper accompanies a demonstration of EdgeWrite on multiple devices.”
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Wobbrock, Jacob O., Aung, Htet Htet, Rothrock, Brandon and Myers, Brad A. (2005): Maximizing the guessability of symbolic input. In: Proceedings of ACM CHI 2005 Conference on Human Factors in Computing Systems 2005. pp. 1869-1872. Available online
“Guessability is essential for symbolic input, in which users enter gestures or keywords to indicate characters or commands, or rely on labels or icons to access features. We present a unified approach to both maximizing and evaluating the guessability of symbolic input. This approach can be used by anyone wishing to design a symbol set with high guessability, or to evaluate the guessability of an existing symbol set. We also present formulae for quantifying guessability and agreement among guesses. An example is offered in which the guessability of the EdgeWrite unistroke alphabet was improved by users from 51.0% to 80.1% without designer intervention. The original and improved alphabets were then tested for their immediate usability with the procedure used by MacKenzie and Zhang (1997). Users entered the original alphabet with 78.8% and 90.2% accuracy after 1 and 5 minutes of learning,”
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» 2004 «
Wobbrock, Jacob O., Myers, Brad A., Aung, Htet Htet and LoPresti, Edmund F. (2004): Text entry from power wheelchairs: edgewrite for joysticks and touchpads. In: Sixth Annual ACM Conference on Assistive Technologies 2004. pp. 110-117. Available online
“Power wheelchair joysticks have been used to control a mouse cursor on desktop computers, but they offer no integrated text entry solution, confining users to point-and-click or point-and-dwell with on-screen keyboards. But on-screen keyboards reduce useful screen real-estate, exacerbate the need for frequent window management, and impose a second focus of attention. By contrast, we present two integrated gestural text entry methods designed for use from power wheelchairs: one for joysticks and the other for touchpads. Both techniques are adaptations of EdgeWrite, originally a stylus-based unistroke method designed for people with tremor. In a preliminary study of 7 power wheelchair users, we found that touchpad EdgeWrite was faster than joystick WiVik, and joystick EdgeWrite was only slightly slower after minimal practice. These findings reflect "walk up and use"-ability and warrant further investigation into extended use.”
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Wobbrock, Jacob O., Myers, Brad A. and Aung, Htet Htet (2004): Writing with a joystick: a comparison of date stamp, selection keyboard, and EdgeWrite. In: Graphics Interface 2004 May 17-19, 2004, London, Ontario, Canada. pp. 1-8. Available online
“A joystick text entry method for game controllers and mobile phones would be valuable, since these devices often have joysticks but no conventional keyboards. But prevalent joystick text entry methods are slow because they are selection-based. EdgeWrite, a new joystick text entry method, is not based on selection but on gestures from a unistroke alphabet. Our experiment shows that this new method is faster, leaves fewer errors, and is more satisfying than date stamp and selection keyboard (two prevalent selection-based methods) for novices after minimal practice. For more practiced users, our results show that EdgeWrite is at least 1.5 times faster than selection keyboard, and 2.4 times faster than date stamp.”
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Myers, Brad A., Nichols, Jeffrey, Wobbrock, Jacob O. and Miller, Robert C. (2004): Taking Handheld Devices to the Next Level. In IEEE Computer, 37 (12) pp. 36-43
» 2003 «
Wobbrock, Jacob O., Myers, Brad A. and Kembel, John A. (2003): EdgeWrite: a stylus-based text entry method designed for high accuracy and stability of motion. In: Proceedings of the 16th annural ACM Symposium on User Interface Software and Technology November, 2-5, 2003, Vancouver, Canada. pp. 61-70. Available online
“EdgeWrite is a new unistroke text entry method for handheld devices designed
to provide high accuracy and stability of motion for people with motor
impairments. It is also effective for able-bodied people. An EdgeWrite user
enters text by traversing the edges and diagonals of a square hole imposed over
the usual text input area. Gesture recognition is accomplished not through
pattern recognition but through the sequence of corners that are hit. This
means that the full stroke path is unimportant and recognition is highly
deterministic, enabling better accuracy than other gestural alphabets such as
Graffiti. A study of able-bodied users showed subjects with no prior experience
were 18% more accurate during text entry with Edge Write than with Graffiti
(p>.05), with no significant difference in speed. A study of 4 subjects with
motor impairments revealed that some of them were unable to do Graffiti, but
all of them could do Edge Write. Those who could do both methods had
dramatically better accuracy with Edge Write.”
Copyrights may apply
» 2002 «
Wobbrock, Jacob O., Forlizzi, Jodi, Hudson, Scott E. and Myers, Brad A. (2002): WebThumb: interaction techniques for small-screen browsers. In: Beaudouin-Lafon, Michel (ed.) Proceedings of the 15th annual ACM symposium on User interface software and technology October 27-30, 2002, Paris, France. pp. 205-208. Available online
“The proliferation of wireless handheld devices is placing the World Wide Web
in the palms of users, but this convenience comes at a high interactive cost.
The Web that came of age on the desktop is ill-suited for use on the small
displays of handhelds. Today, handheld browsing often feels like browsing on a
PC with a shrunken desktop. Overreliance on scrolling is a big problem in
current handheld browsing. Users confined to viewing a small portion of each
page often lack a sense of the overall context -- they may feel lost in a large
page and be forced to remember the locations of items as those items scroll out
of view. In this paper, we present a synthesis of interaction techniques to
address these problems. We implemented these techniques in a prototype,
WebThumb, that can browse the live Web.”
Copyrights may apply
Myers, Brad A., Wobbrock, Jacob O., Yang, Sunny, Yeung, Brian, Nichols, Jeffrey and Miller, Robert (2002): Using handhelds to help people with motor impairments. In: Fifth Annual ACM Conference on Assistive Technologies 2002. pp. 89-96. Available online
“People with Muscular Dystrophy (MD) and certain other muscular and nervous system disorders lose their gross motor control while retaining fine motor control. The result is that they lose the ability to move their wrists and arms, and therefore their ability to operate a mouse and keyboard. However, they can often still use their fingers to control a pencil or stylus, and thus can use a handheld computer such as a Palm. We have developed software that allows the handheld to substitute for the mouse and keyboard of a PC, and tested it with four people (ages 10, 12, 27 and 53) with MD. The 12-year old had lost the ability to use a mouse and keyboard, but with our software, he was able to use the Palm to access email, the web and computer games. The 27-year-old reported that he found the Palm so much better that he was using it full-time instead of a keyboard and mouse. The other two subjects said that our software was much less tiring than using the conventional input devices, and enabled them to use computers for longer periods. We report the results of these case studies, and the adaptations made to our software for people with disabilities.”
Copyrights may apply
Nichols, Jeffrey, Wobbrock, Jacob O., Gergle, Darren and Forlizzi, Jodi (2002): Mediator and medium: doors as interruption gateways and aesthetic displays. In: Proceedings of DIS02: Designing Interactive Systems: Processes, Practices, Methods, & Techniques 2002. pp. 379-386. Available online
“Office doors are more than entrances to rooms, they are entrances to a person's time and attention. People can mediate access to themselves by choosing whether to leave their door open or closed when they are in their office. Doors also serve as a medium for communication, where people can broadcast individual messages to passersby, or accept messages from others who stopped by when the door was closed. These qualities make the door an excellent location for designing solutions that help people better manage their time and attention. In this paper, we present a study of doors, derive design insights from the study, and then realize some of these insights in two cooperating implementations deployed in our workplace.”
Copyrights may apply
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Mar 21st, 2010
Changes to this page (author)
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