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TACCESS Tables of Contents: 010203040506

ACM Transactions on Accessible Computing 6

Editors:Matt Huenerfauth; Kathleen F. McCoy
Standard No:ISSN 1936-7228
Links:Journal Home Page | ACM Digital Library | Table of Contents
  1. TACCESS 2015-03 Volume 6 Issue 1
  2. TACCESS 2015-03 Volume 6 Issue 2
  3. TACCESS 2015-06 Volume 6 Issue 3
  4. TACCESS 2015-06 Volume 6 Issue 4

TACCESS 2015-03 Volume 6 Issue 1

Haptic 3D Surface Representation of Table-Based Data for People With Visual Impairments BIBAFull-Text 1
  Jonas Braier; Katharina Lattenkamp; Benjamin Räthel; Sandra Schering; Michael Wojatzki; Benjamin Weyers
The UN Convention on the Rights of Persons with Disabilities Article 24 states that "States Parties shall ensure inclusive education at all levels of education and life long learning." This article focuses on the inclusion of people with visual impairments in learning processes including complex table-based data. Gaining insight into and understanding of complex data is a highly demanding task for people with visual impairments. Especially in the case of table-based data, the classic approaches of braille-based output devices and printing concepts are limited. Haptic perception requires sequential information processing rather than the parallel processing used by the visual system, which hinders haptic perception to gather a fast overview of and deeper insight into the data. Nevertheless, neuroscientific research has identified great dependencies between haptic perception and the cognitive processing of visual sensing. Based on these findings, we developed a haptic 3D surface representation of classic diagrams and charts, such as bar graphs and pie charts. In a qualitative evaluation study, we identified certain advantages of our relief-type 3D chart approach. Finally, we present an education model for German schools that includes a 3D printing approach to help integrate students with visual impairments.
Accessing Peer Social Interaction: Using Authorable Virtual Peer Technology as a Component of a Group Social Skills Intervention Program BIBAFull-Text 2
  Andrea Tartaro; Justine Cassell; Corina Ratz; Jennifer Lira; Valeria Nanclares-Nogués
Autism spectrum and related communication and social disorders can severely affect some children's ability to engage in peer social interaction. In this article, we describe and evaluate an Authorable Virtual Peer (AVP), technology designed to help children access peer interactions by supporting them in developing critical social skills. Children interact with the AVP in three ways: (1) engaging in face-to-face interaction with a life-sized, computer-animated child; (2) creating new social behaviors for the AVP; and (3) controlling the AVP using a graphical user interface to select appropriate responses while the AVP interacts with another person. Our evaluation suggests that when an AVP is used as an activity during a social group intervention, a common intervention approach used with children with social and communication difficulties, that children's use of specific social behaviors critical to successful social interaction increases during role-play of common social situations with another child.
Filteryedping: Design Challenges and User Performance of Dwell-Free Eye Typing BIBAFull-Text 3
  Diogo Pedrosa; Maria Da Graça Pimentel; Amy Wright; Khai N. Truong
The ability to use the movements of the eyes to write is extremely important for individuals with a severe motor disability. With eye typing, a virtual keyboard is shown on the screen and the user enters text by gazing at the intended keys one at a time. With dwell-based eye typing, a key is selected by continuously gazing at it for a specific amount of time. However, this approach has two possible drawbacks: unwanted selections and slow typing rates. In this study, we propose a dwell-free eye typing technique that filters out unintentionally selected letters from the sequence of letters looked at by the user. It ranks possible words based on their length and frequency of use and suggests them to the user. We evaluated Filteryedping with a series of experiments. First, we recruited participants without disabilities to compare it with another potential dwell-free technique and with a dwell-based eye typing interface. The results indicate it is a fast technique that allows an average of 15.95 words per minute after 100min of typing. Then, we improved the technique through iterative design and evaluation with individuals who have severe motor disabilities. This phase helped to identify and create parameters that allow the technique to be adapted to different users.

TACCESS 2015-03 Volume 6 Issue 2

Papers from Assets 2013

Introduction to the ASSETS'13 Special Issue BIBAFull-Text 4e
  Richard Ladner; Jonathan Lazar
We are pleased to present three articles that are extended versions of conference papers presented at the 15th International ACM SIGACCESS Conference on Computers and Accessibility (ASSETS'13), which was held in Bellevue, Washington, October 21 to 23, 2013. Authors of several top papers from the conference submitted manuscripts for consideration, which underwent a full review process for the ACM Transactions on Accessible Computing. The guest editors for these articles include Jonathan Lazar (Towson University) and Richard Ladner (University of Washington), who served as Program Chair for ASSETS'13.
Experiences of Someone with a Neuromuscular Disease in Operating a PC (and Ways to Successfully Overcome Challenges) BIBAFull-Text 4
  Torsten Felzer; Stephan Rinderknecht
This article describes the experiences of the first author, who was diagnosed with the neuromuscular disease Friedreich's Ataxia more than 25 years ago, with the innovative approach to human-computer interaction characterized by the software tool OnScreenDualScribe. Originally developed by (and for!) the first author, the tool replaces the standard input devices -- that is, keyboard and mouse -- with a small numeric keypad, making optimal use of his abilities. This work attempts to illustrate some of the difficulties the first author usually has to face when operating a computer, due to considerable motor problems. The article will discuss what he tried in the past, and why OnScreenDualScribe, offering various assistive techniques -- including word prediction, an ambiguous keyboard, and stepwise pointing operations -- is indeed a viable alternative. In a pilot study that was repeated multiple times with slight variations over a period of 3 years, the first author's entry rate with OnScreenDualScribe (including early versions of the tool) increased from 1.38wpm to 6.16wpm, while his achievable typing rate went from 12wpm to 3.5wpm in the course of 24 years. However, the ultimate goal is to help not just one single person, but to make the system -- which not only accelerates entry, but also clearly reduces the required effort -- available to anyone with similar conditions.
Improving Public Transit Accessibility for Blind Riders by Crowdsourcing Bus Stop Landmark Locations with Google Street View: An Extended Analysis BIBAFull-Text 5
  Kotaro Hara; Shiri Azenkot; Megan Campbell; Cynthia L. Bennett; Vicki Le; Sean Pannella; Robert Moore; Kelly Minckler; Rochelle H. Ng; Jon E. Froehlich
Low-vision and blind bus riders often rely on known physical landmarks to help locate and verify bus stop locations (e.g., by searching for an expected shelter, bench, or newspaper bin). However, there are currently few, if any, methods to determine this information a priori via computational tools or services. In this article, we introduce and evaluate a new scalable method for collecting bus stop location and landmark descriptions by combining online crowdsourcing and Google Street View (GSV). We conduct and report on three studies: (i) a formative interview study of 18 people with visual impairments to inform the design of our crowdsourcing tool, (ii) a comparative study examining differences between physical bus stop audit data and audits conducted virtually with GSV, and (iii) an online study of 153 crowd workers on Amazon Mechanical Turk to examine the feasibility of crowdsourcing bus stop audits using our custom tool with GSV. Our findings reemphasize the importance of landmarks in nonvisual navigation, demonstrate that GSV is a viable bus stop audit dataset, and show that minimally trained crowd workers can find and identify bus stop landmarks with 82.5% accuracy across 150 bus stop locations (87.3% with simple quality control).
Designing Wheelchair-Based Movement Games BIBAFull-Text 6
  Kathrin M. Gerling; Regan L. Mandryk; Matthew Miller; Michael R. Kalyn; Max Birk; Jan D. Smeddinck
People using wheelchairs have access to fewer sports and other physically stimulating leisure activities than nondisabled persons, and often lead sedentary lifestyles that negatively influence their health. While motion-based video games have demonstrated great potential of encouraging physical activity among nondisabled players, the accessibility of motion-based games is limited for persons with mobility disabilities, thus also limiting access to the potential health benefits of playing these games. In our work, we address this issue through the design of wheelchair-accessible motion-based game controls. We present KINECTWheels, a toolkit designed to integrate wheelchair movements into motion-based games. Building on the toolkit, we developed Cupcake Heaven, a wheelchair-based video game designed for older adults using wheelchairs, and we created Wheelchair Revolution, a motion-based dance game that is accessible to both persons using wheelchairs and nondisabled players. Evaluation results show that KINECTWheels can be applied to make motion-based games wheelchair-accessible, and that wheelchair-based games engage broad audiences in physically stimulating play. Through the application of the wheelchair as an enabling technology in games, our work has the potential of encouraging players of all ages to develop a positive relationship with their wheelchair.

TACCESS 2015-06 Volume 6 Issue 3

Speech and Language Processing for AT

Perspectives on Speech and Language Interaction for Daily Assistive Technology: Introduction to Part 1 of the Special Issue BIBFull-Text 7
  Heidi Christensen; Frank Rudzicz; François PortetJan Alexandersson
Automatic Assessment of Speech Capability Loss in Disordered Speech BIBAFull-Text 8
  Thomas Pellegrini; Lionel Fontan; Julie Mauclair; Jérôme Farinas; Charlotte Alazard-Guiu; Marina Robert; Peggy Gatignol
In this article, we report on the use of an automatic technique to assess pronunciation in the context of several types of speech disorders. Even if such tools already exist, they are more widely used in a different context, namely, Computer-Assisted Language Learning, in which the objective is to assess nonnative pronunciation by detecting learners' mispronunciations at segmental and/or suprasegmental levels. In our work, we sought to determine if the Goodness of Pronunciation (GOP) algorithm, which aims to detect phone-level mispronunciations by means of automatic speech recognition, could also detect segmental deviances in disordered speech. Our main experiment is an analysis of speech from people with unilateral facial palsy. This pathology may impact the realization of certain phonemes such as bilabial plosives and sibilants. Speech read by 32 speakers at four different clinical severity grades was automatically aligned and GOP scores were computed for each phone realization. The highest scores, which indicate large dissimilarities with standard phone realizations, were obtained for the most severely impaired speakers. The corresponding speech subset was manually transcribed at phone level; 8.3% of the phones differed from standard pronunciations extracted from our lexicon. The GOP technique allowed the detection of 70.2% of mispronunciations with an equal rate of about 30% of false rejections and false acceptances. Finally, to broaden the scope of the study, we explored the correlation between GOP values and speech comprehensibility scores on a second corpus, composed of sentences recorded by six people with speech impairments due to cancer surgery or neurological disorders. Strong correlations were achieved between GOP scores and subjective comprehensibility scores (about 0.7 absolute). Results from both experiments tend to validate the use of GOP to measure speech capability loss, a dimension that could be used as a complement to physiological measures in pathologies causing speech disorders.
Automatic Detection of Phone-Based Anomalies in Dysarthric Speech BIBAFull-Text 9
  Imed Laaridh; Corinne Fredouille; Christine Meunier
Perceptual evaluation is still the most common method in clinical practice for diagnosing and following the progression of the condition of people with speech disorders. Although a number of studies have addressed the acoustic analysis of speech productions exhibiting impairments, additional descriptive analysis is required to manage interperson variability, considering speakers with the same condition or across different conditions. In this context, this article investigates automatic speech processing approaches dedicated to the detection and localization of abnormal acoustic phenomena in speech signal produced by people with speech disorders. This automatic process aims at enhancing the manual investigation of human experts while at the same time reducing the extent of their intervention by calling their attention to specific parts of the speech considered as atypical from an acoustical point of view.
   Two different approaches are proposed in this article. The first approach models only the normal speech, whereas the second models both normal and dysarthric speech. Both approaches are evaluated following two strategies: one consists of a strict phone comparison between a human annotation of abnormal phones and the automatic output, while the other uses a "one-phone delay" for the comparison.
   The experimental evaluation of both approaches for the task of detecting acoustic anomalies was conducted on two different corpora composed of French dysarthric speakers and control speakers. These approaches obtain very encouraging results and their potential for clinical uses with different types of dysarthria and neurological diseases is quite promising.
Intelligibility Assessment and Speech Recognizer Word Accuracy Rate Prediction for Dysarthric Speakers in a Factor Analysis Subspace BIBAFull-Text 10
  David Martínez; Eduardo Lleida; Phil Green; Heidi Christensen; Alfonso Ortega; Antonio Miguel
Automated intelligibility assessments can support speech and language therapists in determining the type of dysarthria presented by their clients. Such assessments can also help predict how well a person with dysarthria might cope with a voice interface to assistive technology. Our approach to intelligibility assessment is based on iVectors, a set of measures that capture many aspects of a person's speech, including intelligibility. The major advantage of iVectors is that they compress all acoustic information contained in an utterance into a reduced number of measures, and they are very suitable to be used with simple predictors. We show that intelligibility assessments work best if there is a pre-existing set of words annotated for intelligibility from the speaker to be evaluated, which can be used for training our system. We discuss the implications of our findings for practice.

TACCESS 2015-06 Volume 6 Issue 4

Speech and Language Processing for AT

Perspectives on Speech and Language Interaction for Daily Assistive Technology: Introduction to Part 2 -- Speaking and Reading Aids BIBFull-Text 11
  Frank Rudzicz; Heidi Christensen; François Portet; Jan Alexandersson
Reconstruction of Phonated Speech from Whispers Using Formant-Derived Plausible Pitch Modulation BIBAFull-Text 12
  Ian V. Mcloughlin; Hamid Reza Sharifzadeh; Su Lim Tan; Jingjie Li; Yan Song
Whispering is a natural, unphonated, secondary aspect of speech communications for most people. However, it is the primary mechanism of communications for some speakers who have impaired voice production mechanisms, such as partial laryngectomees, as well as for those prescribed voice rest, which often follows surgery or damage to the larynx. Unlike most people, who choose when to whisper and when not to, these speakers may have little choice but to rely on whispers for much of their daily vocal interaction.
   Even though most speakers will whisper at times, and some speakers can only whisper, the majority of today's computational speech technology systems assume or require phonated speech. This article considers conversion of whispers into natural-sounding phonated speech as a noninvasive prosthetic aid for people with voice impairments who can only whisper. As a by-product, the technique is also useful for unimpaired speakers who choose to whisper.
   Speech reconstruction systems can be classified into those requiring training and those that do not. Among the latter, a recent parametric reconstruction framework is explored and then enhanced through a refined estimation of plausible pitch from weighted formant differences. The improved reconstruction framework, with proposed formant-derived artificial pitch modulation, is validated through subjective and objective comparison tests alongside state-of-the-art alternatives.
Individuality-Preserving Voice Conversion for Articulation Disorders Using Phoneme-Categorized Exemplars BIBAFull-Text 13
  Ryo Aihara; Tetsuya Takiguchi; Yasuo Ariki
We present a voice conversion (VC) method for a person with an articulation disorder resulting from athetoid cerebral palsy. The movements of such speakers are limited by their athetoid symptoms and their consonants are often unstable or unclear, which makes it difficult for them to communicate. Exemplar-based spectral conversion using Nonnegative Matrix Factorization (NMF) is applied to a voice from a speaker with an articulation disorder. In our conventional work, we used a combined dictionary that was constructed from the source speaker's vowels and the consonants from a target speaker without articulation disorders in order to preserve the speaker's individuality. However, this conventional exemplar-based approach needs to use all the training exemplars (frames), and it may cause mismatching of phonemes between input signals and selected exemplars. In order to reduce the mismatching of phoneme alignment, we propose a phoneme-categorized subdictionary and a dictionary selection method using NMF. The effectiveness of this method was confirmed by comparing its effectiveness with that of a conventional Gaussian Mixture Model (GMM)-based and a conventional exemplar-based method.
Making It Simplext: Implementation and Evaluation of a Text Simplification System for Spanish BIBAFull-Text 14
  Horacio Saggion; Sanja Štajner; Stefan Bott; Simon Mille; Luz Rello; Biljana Drndarevic
The way in which a text is written can be a barrier for many people. Automatic text simplification is a natural language processing technology that, when mature, could be used to produce texts that are adapted to the specific needs of particular users. Most research in the area of automatic text simplification has dealt with the English language. In this article, we present results from the Simplext project, which is dedicated to automatic text simplification for Spanish. We present a modular system with dedicated procedures for syntactic and lexical simplification that are grounded on the analysis of a corpus manually simplified for people with special needs. We carried out an automatic evaluation of the system's output, taking into account the interaction between three different modules dedicated to different simplification aspects. One evaluation is based on readability metrics for Spanish and shows that the system is able to reduce the lexical and syntactic complexity of the texts. We also show, by means of a human evaluation, that sentence meaning is preserved in most cases. Our results, even if our work represents the first automatic text simplification system for Spanish that addresses different linguistic aspects, are comparable to the state of the art in English Automatic Text Simplification.