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TACCESS Tables of Contents: 010203040506

ACM Transactions on Accessible Computing 4

Editors:Andrew Sears; Vicki L. Hanson
Standard No:ISSN 1936-7228
Links:Journal Home Page | ACM Digital Library | Table of Contents
  1. TACCESS 2011-11 Volume 4 Issue 1
  2. TACCESS 2012-03 Volume 4 Issue 2
  3. TACCESS 2012-12 Volume 4 Issue 3
  4. TACCESS 2013-07 Volume 4 Issue 4

TACCESS 2011-11 Volume 4 Issue 1

Introduction ASSETS'10 Special Issue BIBAFull-Text 1
  Vicki L. Hanson; Andrew Sears
This article provides an introduction to ASSETS'10 Special Issue.This TACCESS issue is a Special Issue of extended versions of three papers from the ASSETS'10 conference. The ASSETS series of conferences allows an international research community to gather and share information about the latest advances in the use of technology to support and include everyone in society, regardless of age, disability, or situational impairment. The conferences have evolved since the first gathering in 1994, with the current research scope broadened to include topics not envisioned at the beginning of the conference series. The three articles in this issue highlight this research expansion.
Write-N-Speak: Authoring Multimodal Digital-Paper Materials for Speech-Language Therapy BIBAFull-Text 2
  Anne Marie Piper; Nadir Weibel; James D. Hollan
Aphasia is characterized by a reduced ability to understand and/or generate speech and language. Speech-language therapy helps individuals with aphasia regain language and cope with changes in their communication abilities. The therapy process is largely paper-based, making multimodal digital pen technology a promising tool for supporting therapy activities. We report on ten months of field research where we examine the practice of speech-language therapy, implement Write-N-Speak, a digital-paper toolkit for end-user creation of custom therapy materials, and deploy this system for 12 weeks with one therapist-client dyad in a clinical setting. The therapist used Write-N-Speak to create a range of materials including custom interactive worksheets, photographs programmed with the client's voice, and interactive stickers on household items to aid object recognition and naming. We conclude with a discussion of multimodal digital pen technology for this and other therapy activities.
Stroke Therapy through Motion-Based Games: A Case Study BIBAFull-Text 3
  Gazihan Alankus; Rachel Proffitt; Caitlin Kelleher; Jack Engsberg
In the United States alone, more than five million people are living with long term motor impairments caused by a stroke. Recently, video games with affordable motion-based input devices have been proposed as a part of therapy to help people recover lost range of motion and motor control. While researchers have demonstrated the potential utility of therapeutic games through controlled studies, relatively little work has explored their long-term home-based use. We conducted a six-week home study with a 62-year-old woman who was seventeen years post-stroke. She played therapeutic games for approximately one hour a day, five days a week. Over the six weeks, she recovered significant motor abilities, which is unexpected given the time since her stroke. We explore detecting such improvements early, using game logs for daily measurements of motor ability to complement the standard measurements that are taken less often. Through observations and interviews, we present lessons learned about the barriers and opportunities that arise from long-term home-based use of therapeutic games.
Data-Driven Synthesis of Spatially Inflected Verbs for American Sign Language Animation BIBAFull-Text 4
  Pengfei Lu; Matt Huenerfauth
We are studying techniques for producing realistic and understandable animations of American Sign Language (ASL); such animations have accessibility benefits for signers with lower levels of written language literacy. This article describes and evaluates a novel method for modeling and synthesizing ASL animations based on samples of ASL signs collected from native signers. We apply this technique to ASL inflecting verbs, common signs in which the location and orientation of the hands is influenced by the arrangement of locations in 3D space that represent entities under discussion. We train mathematical models of hand movement on animation data of signs produced by a native signer. In evaluation studies with native ASL signers, the verb animations synthesized from our model had similar subjective-rating and comprehension-question scores to animations produced by a human animator; they also achieved higher scores than baseline animations. Further, we examine a split modeling technique for accommodating certain verb signs with complex movement patterns, and we conduct an analysis of how robust our modeling techniques are to reductions in the size of their training data. The modeling techniques in this article are applicable to other types of ASL signs and to other sign languages used internationally. Our models' parameterization of sign animations can increase the repertoire of generation systems and can partially automate the work of humans using sign language scripting systems.

TACCESS 2012-03 Volume 4 Issue 2

Introduction to article 7 BIBAFull-Text 6
  Vicki L. Hanson; Andrew Sears
This issue of Transactions on Accessible Computing contains an article from the two Editors-in-Chief about accessibility research. This article is designed to provide guidance for potential authors about issues taken into consideration when reviewing submissions to the journal. The article, reprinted from an ACM conference proceedings, emphasizes the importance of including representative users in research. Acknowledging well-known difficulties in obtaining sufficient numbers of representative users, the article underscores the fact that users with disabilities often approach tasks in ways that differ from those of users without disabilities, even in situations where differences might not be expected. This highlights the importance of including representative users when researching technologies that aim to address the needs of disabled users. Beyond that, the article seeks to raise awareness of issues related to accessibility research. The goal is to begin critical thinking about research methods to be used in cases where there are a limited number of research participants available and where the variability in participant abilities can be quite large.
Representing users in accessibility research BIBAFull-Text 7
  Andrew Sears; Vicki L. Hanson
The need to study representative users is widely accepted within the human-computer interaction (HCI) community. While exceptions exist, and alternative populations are sometimes studied, virtually any introduction to the process of designing user interfaces will discuss the importance of understanding the intended users as well as the significant impact individual differences can have on how effectively individuals can use various technologies. HCI researchers are expected to provide relevant demographics regarding study participants as well as information about experience using similar technologies. Yet in the field of accessibility, we continue to see studies that do not appropriately include representative users. Highlighting ways to remedy this multifaceted problem, we argue that expectations regarding how accessibility research is conducted and reported must be raised if this field is to have the desired impact with regard to inclusive design, the information technologies studied, and the lives of the individuals studied.
Is accessibility conformance an elusive property? A study of validity and reliability of WCAG 2.0 BIBAFull-Text 8
  Giorgio Brajnik; Yeliz Yesilada; Simon Harper
The Web Content Accessibility Guidelines (WCAG) 2.0 separate testing into both "Machine" and "Human" audits; and further classify "Human Testability" into "Reliably Human Testable" and "Not Reliably Testable"; it is human testability that is the focus of this paper. We wanted to investigate the likelihood that "at least 80% of knowledgeable human evaluators would agree on the conclusion" of an accessibility audit, and therefore understand the percentage of success criteria that could be described as reliably human testable, and those that could not. In this case, we recruited twenty-five experienced evaluators to audit four pages for WCAG 2.0 conformance. These pages were chosen to differ in layout, complexity, and accessibility support, thereby creating a small but variable sample.
   We found that an 80% agreement between experienced evaluators almost never occurred and that the average agreement was at the 70-75% mark, while the error rate was around 29%. Further, trained -- but novice -- evaluators performing the same audits exhibited the same agreement to that of our more experienced ones, but a reduction on validity of 6-13%; the validity that an untrained user would attain can only be a conjecture. Expertise appears to improve (by 19%) the ability to avoid false positives. Finally, pooling the results of two independent experienced evaluators would be the best option, capturing at most 76% of the true problems and producing only 24% of false positives. Any other independent combination of audits would achieve worse results.
   This means that an 80% target for agreement, when audits are conducted without communication between evaluators, is not attainable, even with experienced evaluators, when working on pages similar to the ones used in this experiment; that the error rate even for experienced evaluators is relatively high and further, that untrained accessibility auditors be they developers or quality testers from other domains, would do much worse than this.
Understanding age and technology experience differences in use of prior knowledge for everyday technology interactions BIBAFull-Text 9
  Marita A. O'Brien; Wendy A. Rogers; Arthur D. Fisk
Technology designers must understand relevant prior knowledge in a target user population to facilitate adoption and effective use. To assess prior knowledge used in naturalistic settings, we systematically collected information about technologies used over 10-day periods from older adults with high and low technology experience and younger adults. Technology repertoires for younger adults and high technology older adults were similar; differences reflected typically different needs for kitchen and health care technologies between the age groups. Technology repertoires for low-technology older adults showed substantial technology usage in many categories. Lower usage compared to high-tech older adults for each category was limited primarily to PC and Internet technologies. Experience differences suggest preferences among low-technology older adults for basic technology usage and for working with people rather than technologies.
   Participants in all groups were generally successful using their everyday technologies to achieve their goals. Prior knowledge was the most common attribution for success, but external information was also commonly referenced. Relevant prior knowledge included technical, functional, strategy, and self knowledge. High tech older adults did not report more problems than younger adults, but they did attribute more problems to insufficient prior knowledge. Younger adults attributed more problems to interference from prior knowledge. Low-tech older adults reported fewer problems, typically attributing them to insufficient prior knowledge or product/system faults. We discuss implications for further research and design improvements to increase everyday technology success and adoption for high-tech and low-tech older adults.

TACCESS 2012-12 Volume 4 Issue 3

Introduction to Special Issue on Mobile Technologies for Older Users BIBFull-Text 10
  Joanna McGrenere
How Older Adults Learn to Use Mobile Devices: Survey and Field Investigations BIBAFull-Text 11
  Rock Leung; Charlotte Tang; Shathel Haddad; Joanna Mcgrenere; Peter Graf; Vilia Ingriany
Mobile computing devices, such as smart phones, offer benefits that may be especially valuable to older adults (age 65+). Yet, older adults have been shown to have difficulty learning to use these devices. In the research presented in this article, we sought to better understand how older adults learn to use mobile devices, their preferences and barriers, in order to find new ways to support them in their learning process. We conducted two complementary studies: a survey study with 131 respondents from three age groups (20-49, 50-64, 65+) and an in-depth field study with 6 older adults aged 50+. The results showed, among other things, that the preference for trial-and-error decreases with age, and while over half of older respondents and participants preferred using the instruction manual, many reported difficulties using it. We discuss implications for design and illustrate these implications with an example help system, Help Kiosk, designed to support older adults' learning to use mobile devices.
Special Issue ASSETS 2011 BIBFull-Text 12
  Yeliz Yesilada
Situation-Specific Models of Color Differentiation BIBAFull-Text 13
  David R. Flatla; Carl Gutwin
Color is commonly used to represent categories and values in computer applications, but users with Color-Vision Deficiencies (CVD) often have difficulty differentiating these colors. Recoloring tools have been developed to address the problem, but current recolorers are limited in that they work from a model of only one type of congenital CVD (i.e., dichromatism). This model does not adequately describe many other forms of CVD (e.g., more common congenital deficiencies such as anomalous trichromacy, acquired deficiencies such as cataracts or age-related yellowing of the lens, or temporary deficiencies such as wearing tinted glasses or working in bright sunlight), and so standard recolorers work poorly in many situations. In this article we describe an alternate approach that can address these limitations. The new approach, called Situation-Specific Modeling (SSM), constructs a model of a specific user's color differentiation abilities in a specific situation, and uses that model as the basis for recoloring digital presentations. As a result, SSM can inherently handle all types of CVD, whether congenital, acquired, or environmental. In this article we describe and evaluate several models that are based on the SSM approach. Our first model of individual color differentiation (called ICD-1) works in RGB color space, and a user study showed it to be accurate and robust (both for users with and without congenital CVD). However, three aspects of ICD-1 were identified as needing improvement: the calibration step needed to build the situation-specific model, and the prediction steps used in recoloring were too slow for real-world use; and the results of the model's predictions were too coarse for some uses. We therefore developed three further techniques: ICD-2 reduces the time needed to calibrate the model; ICD-3 reduces the time needed to make predictions with the model; and ICD-4 provides additional information about the degree of differentiability in a prediction. Our final result is a model of the user's color perception that handles any type of CVD, can be calibrated in two minutes, and can find replacement colors in near-real time (~1 second for a 64-color image). The ICD models provide a tool that can greatly improve the perceptibility of digital color for many different types of CVD users, and also demonstrates situation-specific modeling as a new approach that can broaden the applicability of assistive technology.

TACCESS 2013-07 Volume 4 Issue 4

A Haptic Tool for Group Work on Geometrical Concepts Engaging Blind and Sighted Pupils BIBAFull-Text 14
  Jonas Moll; Eva-Lotta Sallnäs Pysander
In the study presented here, two haptic and visual applications for learning geometrical concepts in group work in primary school have been designed and evaluated. The aim was to support collaborative learning among sighted and visually impaired pupils. The first application is a static flattened 3D environment that supports learning to distinguish between angles by means of a 3D haptic device providing touch feedback. The second application is a dynamic 3D environment that supports learning of spatial geometry. The scene is a room with a box containing geometrical objects, which pupils can pick up and move around. The applications were evaluated in four schools with groups of two sighted and one visually impaired pupil. The results showed the support for the visually impaired pupil and for the collaboration to be satisfying. A shared understanding of the workspace could be achieved, as long as the virtual environment did not contain movable objects. Verbal communication was crucial for the work process but haptic guiding to some extent substituted communication about direction. When it comes to joint action between visually impaired and sighted pupils a number of interesting problems were identified when the dynamic and static virtual environments were compared. These problems require further investigation. The study extends prior work in the areas of assistive technology and multimodal communication by evaluating functions for joint haptic manipulation in the unique setting of group work in primary school.
Investigating User Behavior for Authentication Methods: A Comparison between Individuals with Down Syndrome and Neurotypical Users BIBAFull-Text 15
  Yao Ma; Jinjuan Feng; Libby Kumin; Jonathan Lazar
A wide variety of authentication mechanisms have been designed to ensure information security. Individuals with cognitive disabilities depend on computers and the Internet for a variety of tasks and, therefore, use authentication applications on an everyday basis. However, although there have been numerous studies investigating password usage by neurotypical users, there have been no research studies conducted to examine the use of authentication methods by individuals with cognitive disabilities. In this article, we systematically investigate how individuals with cognitive disabilities, specifically Down syndrome (DS), interact with various user authentication mechanisms. This research provides the first benchmark data on the performance of individuals with DS when using multiple authentication methods. It confirms that individuals with DS are capable of using the traditional alphanumeric passwords with reasonable efficiency. The passwords created by individuals with DS are of similar strength to those created by neurotypical people. Graphic passwords are not as effective as traditional alphanumeric and mnemonic passwords regarding efficiency, and are less preferred by the participants. Based on the findings of the study, we propose design guidelines that aim to assist both practitioners and researchers in designing and developing effective authentication applications that fit the specific needs of individuals with DS.