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TACCESS Tables of Contents: 010203040506

ACM Transactions on Accessible Computing 1

Editors:Andrew Sears; Vicki L. Hanson
Standard No:ISSN 1936-7228
Links:Journal Home Page | ACM Digital Library | Table of Contents
  1. TACCESS 2008-05 Volume 1 Issue 1
  2. TACCESS 2008-10 Volume 1 Issue 2
  3. TACCESS 2009-02 Volume 1 Issue 3

TACCESS 2008-05 Volume 1 Issue 1

Introduction BIBFull-Text 1
  Andrew Sears; Vicki Hanson
Guest Editorial BIBFull-Text 2
  Shari Trewin
Evaluation of American Sign Language Generation by Native ASL Signers BIBAKFull-Text 3
  Matt Huenerfauth; Liming Zhao; Erdan Gu; Jan Allbeck
There are many important factors in the design of evaluation studies for systems that generate animations of American Sign Language (ASL) sentences, and techniques for evaluating natural language generation of written texts are not easily adapted to ASL. When conducting user-based evaluations, several cultural and linguistic characteristics of members of the American Deaf community must be taken into account so as to ensure the accuracy of evaluations involving these users. This article describes an implementation and user-based evaluation (by native ASL signers) of a prototype ASL natural language generation system that produces sentences containing classifier predicates, which are frequent and complex spatial phenomena that previous ASL generators have not produced. Native signers preferred the system's output to Signed English animations -- scoring it higher in grammaticality, understandability, and naturalness of movement. They were also more successful at a comprehension task after viewing the system's classifier predicate animations.
Keywords: American Sign Language, accessibility technology for the deaf, animation, evaluation, natural language generation
Goal Crossing with Mice and Trackballs for People with Motor Impairments: Performance, Submovements, and Design Directions BIBAKFull-Text 4
  Jacob O. Wobbrock; Krzysztof Z. Gajos
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.
Keywords: Fitts' law, Steering law, Target acquisition, area pointing, goal crossing, motor impairments, mouse pointing, movement microstructure, path analysis, submovements, throughput
The Field Evaluation of a Mobile Digital Image Communication Application Designed for People with Aphasia BIBAKFull-Text 5
  Meghan Allen; Joanna McGrenere; Barbara Purves
PhotoTalk is an application for a mobile device that allows people with aphasia to capture and manage digital photographs to support face-to-face communication. Unlike any other augmentative and alternative communication device for people with aphasia, PhotoTalk focuses solely on image capture and organization and is designed to be used independently. Our project used a streamlined process with three phases: (1) a rapid participatory design and development phase with two speech-language pathologists acting as representative users, (2) an informal usability study with five aphasic participants, which caught usability problems and provided preliminary feedback on the usefulness of PhotoTalk, and (3) a one-month field evaluation with two aphasic participants followed by a one-month secondary field evaluation with one aphasic participant, which showed that they all used it regularly and relatively independently, although not always for its intended communicative purpose. Our field evaluations demonstrated PhotoTalk's promise in terms of its usability and usefulness in everyday communication.
Keywords: AAC devices, aphasia, cognitive disability, evaluation, field study, mobile technology, participatory design
Sibylle, An Assistive Communication System Adapting to the Context and Its User BIBAKFull-Text 6
  Tonio Wandmacher; Jean-Yves Antoine; Franck Poirier; Jean-Paul Départe
In this article, we describe the latest version of Sibylle, an AAC system that permits persons who have severe physical disabilities to enter text with any computer application, as well as to compose messages to be read out through speech synthesis. The system consists of a virtual keyboard comprising a set of keypads that allow for the entering of characters or full words by a single-switch selection process. It also includes a sophisticated word prediction component which dynamically calculates the most appropriate words for a given context. This component is auto-adaptive, that is, it learns with every text the user enters. It thus adapts its predictions to the user's language and the current topic of communication as well. So far, the system works for French, German and English. Earlier versions of Sibylle have been used since 2001 in a rehabilitation center (Kerpape, France).
Keywords: Augmentative and alternative communication, keystroke saving rate, latent semantic analysis, user adaptation, virtual keyboard, word prediction

TACCESS 2008-10 Volume 1 Issue 2

Computers and People with Disabilities BIBAKFull-Text 7
  Ephraim P. Glinert; Bryant W. York
Editors' comments: “Computers and People with Disabilities” is a reprint of an article originally published in Communications of the ACM in 1992. In this article, Glinert and York issued a “call-to-arms” for research and development on technologies for people with disabilities. Specifically, they highlighted that human-computer interfaces at the time generally failed to take into account the needs of disabled users. Their challenge was to change computing culture to address this need. Their article remains timely today in its consideration of government, industry, and private foundations working with researchers to achieve accessible technology. With the recent launch of Transactions on Accessible Computing, this seems an appropriate time to consider progress in the field since, as well as current research trends.
   The reprinting of this article is followed by four commentaries by leaders in accessibility research. Each was cited in the 1992 article and each now gives their view on how the field has progressed since that time. In their commentaries, some themes emerge and new technologies are discussed. In short, their commentaries point to both a great deal of progress and a lack of progress. All four of the commentators note areas where computing continues to present barriers rather than assist users with disabilities.
   Alistair Edwards sets the stage with a look back at interfaces and input technologies popular in 1992, with attention paid to access problems related to graphical user interfaces (GUIs) that have consumed much research energy since 1992. Alan Newell highlights disability concerns that were not given large research consideration in 1992, but which have now become significant due, in large part, to changes in global demographics. Specifically, he brings visibility to research on older adults and cognitively disabled users.
   A number of advances in technology and methodology since 1992 are discussed by the commentators. The ubiquity of computing and its critical adoption in the world today are highlighted. The commentators reflect, for example, on technologies produced by research for disabled users that have now impacted mainstream offerings on standards for accessibility that have emerged worldwide and their impact and on assistive technologies that have been developed. Critically, the proliferation of the World Wide Web was not foreseen in 1992 and its use by people with disabilities is discussed. Gregg Vanderheiden considers the opportunity afforded by the Web to provide widespread availability of accessible software.
   Glinert and York discussed the need for design for disability. While research relevant to users with disabilities is gaining momentum, the commentators indicate that users with disabilities still struggle with much of today's IT. The commentators note current trends toward designs that take into account disabled users. Notably, Richard Ladner ends his commentary by mentioning the issue of empowerment. Users with disabilities have moved beyond simply needing the protections of regulation that were emerging in 1992, to being active participants in designing solutions to allow full participation in the current social, political, and economic environments.
   Together, these articles provide a great deal of food for thought on technology advances and new considerations of accessible technology. Has the change in computing culture envisioned by Glinert and York taken hold?
   Vicki L. Hanson and Andrew Sears
   Co-Editors in Chief
Keywords: Accessibility, HCI, Web, inclusive design, interfaces, ubiquitous computing, universal access
Keeping Up with Technology: Commentary on "Computers and People with Disabilities" BIBAKFull-Text 8
  Alistair D. N. Edwards
This is a personal response to rereading the Glinert and York [1992] article “Computers and People with Disabilities.” Comparing the world of assistive technology as it was in 1992 and as it now appears is instructive in terms of the things which have changed -- and those which have not. The technology has certainly developed. This applies both to the mainstream and to the assistive technology which aims to make the mainstream accessible. So, in 1992, the GUI was a threat to visually impaired computer users; now there are powerful screen readers available. Yet what does not appear to have changed much is the fact that assistive technologies continue to lag behind the mainstream, constantly having to “catch up.” Also, while there has been some increase in awareness of the need for accessibility, there is still scope for that awareness to be translated into action.
Keywords: Interfaces
Accessible Computing -- Past Trends and Future Suggestions: Commentary on "Computers and People with Disabilities" BIBAKFull-Text 9
  Alan F. Newell
This article gives a personal perspective on Glinert and York's 1992 paper, focusing on whether and how the situation has changed over the past 15 years, and makes recommendations for the future of the field of accessible computing with a particular focus on the needs of older people and people with cognitive dysfunction.
Keywords: Assistive technology, cognitive dysfunction, inclusive design, older and disabled people, theater in design
Ubiquitous Accessibility, Common Technology Core, and Micro-Assistive Technology: Commentary on "Computers and People with Disabilities" BIBAKFull-Text 10
  Gregg C. Vanderheiden
Much has changed since 1992 when the original CACM article by Ephraim Glinert and Bryant York was published. In the early 1990's, accessibility was mostly an add-on, with only Apple computers having built-in access. Computers were playing an increasingly important role in education and employment, but had not yet completely integrated themselves into all aspects of life as completely as they have today. The World Wide Web as we know it had not yet been born. Today there are accessibility features built directly into every major operating system, and one OS even includes a built-in screen reader. Assistive technologies are more numerous and capable. And awareness of the importance of access is much higher. However, some things have not changed. Assistive technologies lag behind mainstream technologies in both compatibility and functionality. Effective assistive technologies are often beyond the financial reach of those who need them. Effective assistive technologies are not available in many countries and many languages, even though technology is reaching into education, employment, and daily living of more countries and more people in each country every year. In moving forward we need to build on what we have achieved and explore new concepts, such as a common technical core, ubiquitous accessibility, micro assistive technology, and free public accessibility. Cooperative and collaborative approaches also need to be explored if we are to have any hope of catching up and keeping up with the ever-accelerating mainstream information and communication technologies.
Keywords: Interfaces, micro-AT, ubiquitous accessibility
Access and Empowerment: Commentary on "Computers and People with Disabilities" BIBAKFull-Text 11
  Richard E. Ladner
A number of positive changes have taken place since Glinert and York's 1992 call-to-arms. Progress reviewed in this article includes evolving considerations of universal design in the marketplace, ubiquitous computing with accessibility features, increasing computing research and conference venues that address needs of users with disabilities, and attention to the importance of user empowerment in development.
Keywords: Universal design, Web, ubiquitous computing, user-centered design
Multimodal Trajectory Playback for Teaching Shape Information and Trajectories to Visually Impaired Computer Users BIBAKFull-Text 12
  Andrew Crossan; Stephen Brewster
There are difficulties in presenting nontextual or dynamic information to blind or visually impaired users through computers. This article examines the potential of haptic and auditory trajectory playback as a method of teaching shapes and gestures to visually impaired people. Two studies are described which test the success of teaching simple shapes. The first study examines haptic trajectory playback alone, played through a force-feedback device, and compares performance of visually impaired users with sighted users. It demonstrates that the task is significantly harder for visually impaired users. The second study builds on these results, combining force-feedback with audio to teach visually impaired users to recreate shapes. The results suggest that users performed significantly better when presented with multimodal haptic and audio playback of the shape, rather than haptic only. Finally, an initial test of these ideas in an application context is described, with sighted participants describing drawings to visually impaired participants through touch and sound. This study demonstrates in what situations trajectory playback can prove a useful role in a collaborative setting.
Keywords: Accessibility, evaluation, multimodal, trajectory playback

TACCESS 2009-02 Volume 1 Issue 3

Introduction to the Special Issue on AAC BIBAKFull-Text 13
  Kathleen F. McCoy; Annalu Waller
This article presents an introduction to the special issue on Augmentative and Alternative Communication (AAC).
Keywords: Alternative and augmentative communication, human-computer interaction
Conception and Experimentation of a Communication Device with Adaptive Scanning BIBAKFull-Text 14
  Souhir Ghedira; Pierre Pino; Guy Bourhis
For some people with motor disabilities and speech disorders, the only way to communicate and to have some control over their environment is through the use of a controlled scanning system operated by a single switch. The main problem with these systems is that the communication process tends to be exceedingly slow, since the system must scan through the available choices one at a time until the desired message is reached. One way of raising the speed of message selection is to optimize the elementary scanning delay in real time so that it allows the user to make selections as quickly as possible without making too many errors. With this objective in mind, this article presents a method for optimizing the scanning delay, which is based on an analysis of the data recorded in “log files” while applying the EDiTH system [Digital Teleaction Environment for People with Disabilities]. This analysis makes it possible to develop a human-machine interaction model specific to the study, and then to establish an adaptive algorithm for the calculation of the scanning delay. The results obtained with imposed scenarios and then in ecological situations provides a confirmation that our algorithms are effective in dynamically adapting a scan speed. The main advantage offered by the procedure proposed is that it works on timing information alone and thus does not require any knowledge of the scanning device itself. This allows it to work with any scanning device.
Keywords: Alternative communication, Model Human Processor, adaptative scanning rate, modeling, scanning system
The Effect of Voice Output on AAC-Supported Conversations of Persons with Alzheimer's Disease BIBAKFull-Text 15
  Melanie Fried-Oken; Charity Rowland; Glory Baker; Mayling Dixon; Carolyn Mills; Darlene Schultz; Barry Oken
The purpose of this study was to determine whether the presence or absence of digitized 1-2-word voice output on a direct selection, customized Augmentative and Alternative Communication (AAC) device would affect the impoverished conversations of persons with dementia. Thirty adults with moderate Alzheimer’s disease participated in two personally relevant conversations with an AAC device. For twelve of the participants the AAC device included voice output. The AAC device was the FlexiboardTM containing sixteen messages needed to discuss a favorite autobiographical topic chosen by the participant and his/her family caregivers. Ten-minute conversations were videotaped in participants’ residences and analyzed for four conversational measures related to the participants’ communicative behavior. Results show that AAC devices with digitized voice output depress conversational performance and distract participants with moderate Alzheimer’s disease as compared to similar devices without voice output. There were significantly more 1-word utterances and fewer total utterances when AAC devices included voice output, and the rate of topic elaborations/initiations was significantly lower when voice output was present. Discussion about the novelty of voice output for this population of elders and the need to train elders to use this technology is provided.
Keywords: Alzheimer’s disease, Augmentative and Alternative Communication (AAC), Dementia, digitized speech synthesis, language
Evaluating the STANDUP Pun Generating Software with Children with Cerebral Palsy BIBAKFull-Text 16
  Annalu Waller; Rolf Black; David A. O'Mara; Helen Pain; Graeme Ritchie; Ruli Manurung
The interactive STANDUP software was developed to provide children who use augmentative and alternative communication (AAC) with a “language playground.” The software provides appropriate functionality for users with physical, speech, and language impairments to generate and tell novel punning riddles at different levels of complexity. STANDUP was evaluated with nine children with cerebral palsy during an eight-week study. Results show that the participants were able to generate and tell novel jokes with minimal or no support. The use of STANDUP impacted favorably on general AAC use. The study results also suggested that STANDUP could potentially have a positive effect on social and pragmatic skills. Further research to investigate the impact of STANDUP on communication skills is proposed. Suggestions for future software development include providing users with opportunities to complete jokes and to integrate online dictionaries when new vocabulary is encountered.
Keywords: Alternative and augmentative communication, computational humor, speech generation devices
User Interaction with Word Prediction: The Effects of Prediction Quality BIBAKFull-Text 17
  Keith Trnka; John McCaw; Debra Yarrington; Kathleen F. McCoy; Christopher Pennington
Word prediction systems can reduce the number of keystrokes required to form a message in a letter-based AAC system. It has been questioned, however, whether such savings translate into an enhanced communication rate due to the additional overhead (e.g., shifting of focus and repeated scanning of a prediction list) required in using such a system. Our hypothesis is that word prediction has high potential for enhancing AAC communication rate, but the amount is dependent in a complex way on the accuracy of the predictions. Due to significant user interface variations in AAC systems and the potential bias of prior word prediction experience on existing devices, this hypothesis is difficult to verify. We present a study of two different word prediction methods compared against letter-by-letter entry at simulated AAC communication rates. We find that word prediction systems can in fact speed communication rate (an advanced system gave a 58.6% improvement), and that a more accurate word prediction system can raise the communication rate higher than is explained by the additional accuracy of the system alone due to better utilization (93.6% utilization for advanced versus 78.2% for basic).
Keywords: Word prediction, communication rate, user study