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TACCESS Tables of Contents: 010203040506

ACM Transactions on Accessible Computing 2

Editors:Andrew Sears; Vicki L. Hanson
Standard No:ISSN 1936-7228
Links:Journal Home Page | ACM Digital Library | Table of Contents
  1. TACCESS 2009-05 Volume 2 Issue 1
  2. TACCESS 2009-06 Volume 2 Issue 2
  3. TACCESS 2010-03 Volume 2 Issue 3
  4. TACCESS 2010-06 Volume 2 Issue 4

TACCESS 2009-05 Volume 2 Issue 1

Introduction to the Special Issue on Aging and Information Technology BIBAKFull-Text 1
  Sara J. Czaja; Peter Gregor; Vicki L. Hanson
This article provides an introduction to the Special Issue on Aging.
Keywords: Aging, cognitive aging, instruction, menu design, older adults, pen interfaces, quality of life technology, spoken dialog systems, user privacy preferences, video modeling, voice interfaces
Being Old Doesn't Mean Acting Old: How Older Users Interact with Spoken Dialog Systems BIBAKFull-Text 2
  Maria Wolters; Kallirroi Georgila; Johanna D. Moore; Sarah E. MacPherson
Most studies on adapting voice interfaces to older users work top-down by comparing the interaction behavior of older and younger users. In contrast, we present a bottom-up approach. A statistical cluster analysis of 447 appointment scheduling dialogs between 50 older and younger users and 9 simulated spoken dialog systems revealed two main user groups, a "social" group and a "factual" group. "Factual" users adapted quickly to the systems and interacted efficiently with them. "Social" users, on the other hand, were more likely to treat the system like a human, and did not adapt their interaction style. While almost all "social" users were older, over a third of all older users belonged in the "factual" group. Cognitive abilities and gender did not predict group membership. We conclude that spoken dialog systems should adapt to users based on observed behavior, not on age.
Keywords: Aging, clustering, cognitive aging, spoken dialog systems, voice interfaces
Exploring Methods to Improve Pen-Based Menu Selection for Younger and Older Adults BIBAKFull-Text 3
  Karyn Moffatt; Joanna McGrenere
Tablet PCs are gaining popularity, but many individuals still struggle with pen-based interaction. In a previous baseline study, we examined the types of difficulties younger and older adults encounter when using pen-based input. The research reported in this article seeks to address one of these errors, namely, missing just below. This error occurs in a menu selection task when a user's selection pattern is downwardly shifted, such that the top edge of the menu item below the target is selected relatively often, while the corresponding top edge of the target itself is seldom selected. We developed two approaches for addressing missing just below errors: reassigning selections along the top edge and deactivating them. In a laboratory evaluation, only the deactivated edge approach showed promise overall. Further analysis of our data revealed that individual differences played a large role in our results and identified a new source of selection difficulty. Specifically, we observed two error-prone groups of users: the low hitters, who, like participants in the baseline study, made missing just below errors, and the high hitters, who, in contrast, had difficulty with errors on the item above. All but one of the older participants fell into one of these error-prone groups, reinforcing that older users do need better support for selecting menu items with a pen. Preliminary analysis of the performance data suggests both of our approaches were beneficial for the low hitters, but that additional techniques are needed to meet the needs of the high hitters and to address the challenge of supporting both groups in a single interface.
Keywords: Pen-based target acquisition, aging, interaction techniques, menu design, older users
Video Modeling for Training Older Adults to Use New Technologies BIBAKFull-Text 4
  Doreen Struve; Hartmut Wandke
The increasing permeation of technology in our society leads to the challenge that everybody needs to interact with technology systems. Older adults often meet difficulties while trying to interact with complex, demanding systems in their daily life. One approach to enable older adults to use new technologies in a safe and efficient way is the provision of training programs. In this article we report about a promising training strategy using video modeling in conjunction with other instructional methods to enhance learning. Cognitive as well as socio-motivational aspects will be addressed. We assessed if guided error training in video modeling will improve learning outcomes for a Ticket Vending Machine (TVM). To investigate if the training method might be beneficial for younger adults as well, we compared 40 younger and 40 older adult learners in a guided error training course with error-free training. Younger and older participants made fewer mistakes in guided error training, but no differences occurred in task completion times. Moreover, self-efficacy increased with training for both age groups, but no significant differences were found for the training condition. Analysis of knowledge gains showed a significant benefit of guided error training in structural knowledge. Overall, the results showed that guided error training may enhance learning for younger and older adults who are learning to use technology.
Keywords: Instruction, guided error training, older adults, self-efficacy, technology use, video modeling
Disability, Age, and Informational Privacy Attitudes in Quality of Life Technology Applications: Results from a National Web Survey BIBAKFull-Text 5
  Scott Beach; Richard Schulz; Julie Downs; Judith Matthews; Bruce Barron; Katherine Seelman
Technology aimed at enhancing function and enabling independent living among older and disabled adults is a growing field of research. Privacy concerns are a potential barrier to adoption of such technology. Using data from a national Web survey (n=1,518), we focus on perceived acceptability of sharing information about toileting, taking medications, moving about the home, cognitive ability, driving behavior, and vital signs with five targets: family, healthcare providers, insurance companies, researchers, and government. We also examine acceptability of recording the behaviors using three methods: video with sound, video without sound, and sensors. Results show that sharing or recording information about toileting behavior; sharing information with the government and insurance companies; and recording the information using video were least acceptable. Respondents who reported current disability were significantly more accepting of sharing and recording of information than nondisabled adults, controlling for demographic variables, general technology attitudes, and assistive device use. Results for age were less consistent, although older respondents tended to be more accepting than younger respondents. The study provides empirical evidence from a large national sample of the implicit trade-offs between privacy and the potential for improved health among older and disabled adults in quality of life technology applications.
Keywords: User privacy preferences, quality of life technology

TACCESS 2009-06 Volume 2 Issue 2

Guest Editorial BIBFull-Text 7
  Armando Barreto; Torsten Felzer
A3: HCI Coding Guideline for Research Using Video Annotation to Assess Behavior of Nonverbal Subjects with Computer-Based Intervention BIBAKFull-Text 8
  Joshua Hailpern; Karrie Karahalios; James Halle; Laura Dethorne; Mary-Kelsey Coletto
HCI studies assessing nonverbal individuals (especially those who do not communicate through traditional linguistic means: spoken, written, or sign) are a daunting undertaking. Without the use of directed tasks, interviews, questionnaires, or question-answer sessions, researchers must rely fully upon observation of behavior, and the categorization and quantification of the participant's actions. This problem is compounded further by the lack of metrics to quantify the behavior of nonverbal subjects in computer-based intervention contexts. We present a set of dependent variables called A3 (pronounced A-Cubed) or Annotation for ASD Analysis, to assess the behavior of this demographic of users, specifically focusing on engagement and vocalization. This paper demonstrates how theory from multiple disciplines can be brought together to create a set of dependent variables, as well as demonstration of these variables, in an experimental context. Through an examination of the existing literature, and a detailed analysis of the current state of computer vision and speech detection, we present how computer automation may be integrated with the A3 guidelines to reduce coding time and potentially increase accuracy. We conclude by presenting how and where these variables can be used in multiple research areas and with varied target populations.
Keywords: ASD, Autism, Kappa, annotation, audio feedback, coding, guideline, intervention, nonverbal, point-by-point agreement, reliability, video, visualization
A Linguistically Motivated Model for Speed and Pausing in Animations of American Sign Language BIBAKFull-Text 9
  Matt Huenerfauth
Many deaf adults in the United States have difficulty reading written English text; computer animations of American Sign Language (ASL) can improve these individuals' access to information, communication, and services. Planning and scripting the movements of a virtual character's arms and body to perform a grammatically correct and understandable ASL sentence is a difficult task, and the timing subtleties of the animation can be particularly challenging. After examining the psycholinguistics literature on the speed and timing of ASL, we have designed software to calculate realistic timing of the movements in ASL animations. We have built algorithms to calculate the time-duration of signs and the location/length of pauses during an ASL animation. To determine whether our software can improve the quality of ASL animations, we conducted a study in which native ASL signers evaluated the ASL animations processed by our algorithms. We have found that: (1) adding linguistically motivated pauses and variations in sign-durations improved signers' performance on a comprehension task and (2) these animations were rated as more understandable by ASL signers.
Keywords: American Sign Language, accessibility technology for the deaf, animation, evaluation, natural language generation
The Development and Evaluation of Performance-Based Functional Assessment: A Methodology for the Measurement of Physical Capabilities BIBAKFull-Text 10
  Kathleen J. Price; Andrew Sears
Understanding and describing the physical capabilities of users with motor impairments is a significant challenge for accessibility researchers and system designers alike. Current practice is to use descriptors such as medical diagnoses to represent a person's physical capabilities. This solution is not adequate due to similarities in functional capabilities between diagnoses as well as differences in capabilities within a diagnosis. An alternative is user self-reporting or observation by another person, but these solutions can be problematic because they rely on individual interpretations of capabilities and may introduce unwanted bias. The current research focuses on defining an objective, quantifiable, repeatable, and efficient methodology for assessing an individual's physical capabilities in relation to use of information technologies. Thirty-one users with a range of physical capabilities participated in the evaluation of the proposed performance-based functional assessment methodology. Building on the current standard for such assessments, multiple observers provided independent assessments that served as the gold standard for comparison. Promising metrics produced through the performance-based assessment were identified through comparisons with these observer evaluations. Predictive models were then generated via regression and correlation analysis. The models were validated using a three-fold validation process. Results from this initial research are encouraging, with the resulting models explaining up to 92% of the variance in user capabilities. Directions for future research are discussed.
Keywords: Functional assessment, HCI, accessibility, physical capabilities
Exploring Visual and Motor Accessibility in Navigating a Virtual World BIBAKFull-Text 11
  Shari Trewin; Mark Laff; Vicki Hanson; Anna Cavender
For many millions of users, 3D virtual worlds provide an engaging, immersive experience heightened by a synergistic combination of visual realism with dynamic control of the user's movement within the virtual world. For individuals with visual or dexterity impairments, however, one or both of those synergistic elements are impacted, reducing the usability and therefore the utility of the 3D virtual world. This article considers what features are necessary to make virtual worlds usable by such individuals. Empirical work has been based on a multiplayer 3D virtual world game called PowerUp, to which we have built in an extensive set of accessibility features. These features include in-world navigation and orientation tools, font customization, self-voicing text-to-speech output, key remapping options, and keyboard-only and mouse-only navigation. Through empirical work with legally blind teenagers and adults with cerebral palsy, these features have been refined and validated. Whereas accessibility support for users with visual impairment often revolves around keyboard navigation, these studies emphasized the need to support visual aspects of pointing device actions too. Other notable findings include use of speech to supplement sound effects for novice users, and, for those with cerebral palsy, a general preference to use a pointing device to look around the world, rather than keys or on-screen buttons. The PowerUp accessibility features provide a core level of accessibility for the user groups studied.
Keywords: 3D, accessibility, audio interfaces, cerebral palsy, input, virtual worlds

TACCESS 2010-03 Volume 2 Issue 3

Universal Design of Auditory Graphs: A Comparison of Sonification Mappings for Visually Impaired and Sighted Listeners BIBAKFull-Text 12
  B. N. Walker; L. M. Mauney
Determining patterns in data is an important and often difficult task for scientists and students. Unfortunately, graphing and analysis software typically is largely inaccessible to users with vision impairment. Using sound to represent data (i.e., sonification or auditory graphs) can make data analysis more accessible; however, there are few guidelines for designing such displays for maximum effectiveness. One crucial yet understudied design issue is exactly how changes in data (e.g., temperature) are mapped onto changes in sound (e.g., pitch), and how this may depend on the specific user. In this study, magnitude estimation was used to determine preferred data-to-display mappings, polarities, and psychophysical scaling functions relating data values to underlying acoustic parameters (frequency, tempo, or modulation index) for blind and visually impaired listeners. The resulting polarities and scaling functions are compared to previous results with sighted participants. There was general agreement about polarities obtained with the two listener populations, with some notable exceptions. There was also evidence for strong similarities regarding the magnitudes of the slopes of the scaling functions, again with some notable differences. For maximum effectiveness, sonification software designers will need to consider carefully their intended users' vision abilities. Practical implications and limitations are discussed.
Keywords: Magnitude estimation, auditory display, visually impaired
Computer Usage by Children with Down Syndrome: Challenges and Future Research BIBAKFull-Text 13
  Jinjuan Feng; Jonathan Lazar; Libby Kumin; Ant Ozok
Children with Down syndrome, like neurotypical children, are growing up with extensive exposure to computer technology. Computers and computer-related devices have the potential to help these children in education, career development, and independent living. Our understanding of computer usage by this population is quite limited. Most of the software, games, and Web sites that children with Down syndrome interact with are designed without consideration of their special needs, making the applications less effective or completely inaccessible. We conducted a large-scale survey that collected computer usage information from the parents of approximately six hundred children with Down syndrome. This article reports the text responses collected in the survey and is intended as a step towards understanding the difficulties children with Down syndrome experience while using computers. The relationship between the age and the specific type of difficulties, as well as related design challenges are also reported. A number of potential research directions and hypotheses are identified for future studies. Due to limitations in survey methodology, the findings need to be further validated through hypothesis-driven, empirical studies.
Keywords: Down syndrome, children, computer use, human-computer interaction

TACCESS 2010-06 Volume 2 Issue 4

ITHACA: An Open Source Framework for Building Component-Based Augmentative and Alternative Communication BIBAKFull-Text 14
  A Applications; Alexandros Pino; Georgios Kouroupetroglou
As an answer to the disabled community's odyssey to gain access to adaptable, modular, multilingual, cheap and sustainable Augmentative and Alternative Communication (AAC) products, we propose the use of the ITHACA framework. It is a software environment for building component-based AAC applications, grounded on the Design for All principles and a hybrid -- community and commercial -- Open Source development model. ITHACA addresses the developers, the vendors, as well as the people who use AAC. We introduce a new viewpoint on the AAC product design-develop-distribute lifecycle, and a novel way to search-select-modify-maintain the AAC aid. ITHACA provides programmers with a set of tools and reusable Open Source code for building AAC software components. It also facilitates AAC product vendors to put together sophisticated applications using the available on the Web, independently premanufactured, free or commercial software parts. Furthermore, it provides people who use AAC with a variety of compatible AAC software products which incorporate multimodal, user-tailored interfaces that can fulfill their changing needs. The ITHACA architecture and the proposed fusion of past and current approaches, trends and technologies are explained. ITHACA has been successfully applied by implementing a family of AAC products, based on interchangeable components. Several ready to use ITHACA-based components, including on-screen keyboards, Text-to-Speech, symbol selection sets, e-chatting, emailing, and scanning-based input, as well as four complete communication aids addressing different user cases have been developed. This demonstration showed good acceptance of the ITHACA applications and substantial improvement of the end users' communication skills. Developers' experience on working in ITHACA's Open Source projects was also positively evaluated. More importantly, the potential contribution of the component-based framework and Open Source development model combination to the AAC community emerged.
Keywords: Augmentative and alternative communication, component, design for all, framework, open source
Towards A Universally Usable Human Interaction Proof: Evaluation of Task Completion Strategies BIBAKFull-Text 15
  Graig Sauer; Jonathan Lazar; Harry Hochheiser; Jinjuan Feng
The need for security features to stop spam and bots has prompted research aimed at developing human interaction proofs (HIPs) that are both secure and easy to use. The primarily visual techniques used in these HIP tools present difficulties for users with visual impairments. This article reports on the development of Human-Interaction Proof, Universally Usable (HIPUU), a new approach to human-interaction proofs based on identification of a series of sound/image pairs. Simultaneous presentation of a single, unified task in two alternative modalities provides multiple paths to successful task completion. We present two alternative task completion strategies, based on differing input strategies (menu-based vs. free text entry). Empirical results from studies involving both blind and sighted users validate both the usability and accessibility of these differing strategies, with blind users achieving successful task completion rates above 90%. The strengths of the alternate task completion strategies are discussed, along with possible approaches for improving the robustness of HIPUU.
Keywords: CAPTCHA, HIP, blind users, security, universal usability
Assessing Fit of Nontraditional Assistive Technologies BIBAKFull-Text 16
  Adriane B. Randolph; Melody M. Moore Jackson
There is a variety of brain-based interface methods which depend on measuring small changes in brain signals or properties. These methods have typically been used for nontraditional assistive technology applications. Non-traditional assistive technology is generally targeted for users with severe motor disabilities which may last long-term due to illness or injury or short-term due to situational disabilities. Control of a nontraditional assistive technology can vary widely across users depending upon many factors ranging from health to experience. Unfortunately, there is no systematic method for assessing usability of nontraditional assistive technologies to achieve the best control. The current methods to accommodate users through trial-and-error result in the loss of valuable time and resources as users sometimes have diminishing abilities or suffer from terminal illnesses. This work describes a methodology for objectively measuring an individual's ability to control a specific nontraditional assistive technology, thus expediting the technology-fit process.
Keywords: assistive technology, brain-based interfaces, brain-computer interface, direct-brain interface, functional near-infrared, galvanic skin response, individual characteristics, user profiles