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| Accessible Design: Problems and Solutions A Literature Review to Support the ITTATC Needs Assessment |
Go back to Section 2: Literature Review Results
Go forward to B: Assessment Methodologies
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A: Assistive Technologies
- Introduction
- A-1. What are the state-of-the-art of speech-based/natural language
technologies?
- A-2. What are the state-of-the-art of auditory information displays?
- A-3. What are the state-of-the-art of haptic interfaces?
- A-4. What are the state-of-the-art of gesture recognition technologies?
- A-5. What are the state-of-the-art of interactive communication limited vocabulary dialogues?
Introduction
The states of the art of the following assistive technology categories were reviewed: speech-based/natural language technologies, auditory information displays, haptic interfaces, gesture recognition technologies, and interactive communication limited vocabulary dialogues. Numerous software products have been designed, but there are many challenges that they have not been able to overcome, and many improvements that need to be made to make them truly accessible (Karat, et al, 1999; Mane, et al, 1996; Martin, et al, 1996). Grammar complexity, vocabulary size, and environmental factors present the greatest barriers to speech-based technologies (McMillan, et al, 1997). However, when utilized on a limited basis, perhaps with a limited vocabulary size, speech based interfaces are very beneficial to people with visual impairments.
Auditory icons and earcons provide an excellent means to provide information through the auditory channel. They can be effective at providing complex information (Bussemakers, et al, 2000; Leung, 1997) that would normally have been provided via a visual channel. Auditory web browsers, if designed appropriately, can be useful tools for the visually and mobility impaired (Feworn, et al, 2000; Wynblatt, et al, 1997). However, the major obstacle in the use of auditory web browsers is that not all web sites are accessible in the auditory domain. For example, non-tagged graphics and PDF files cannot be easily interpreted by auditory web-browsers. Care must be taken to design web sites so that access to information by people with visual impairments is not prohibited. Sonification, or the encoding of data into time varying auditory streams, provides great potential for developing a variety of tools (Kramer, et al, 1997; Leplâtre, et al, 2000). Current research has shown that sonification may be used to replace or enhance some types of real time visual displays that would normally not be available to people with visual impairments.
The development of haptic interfaces is challenged by the difficulty in simulating tactile sensations. One early approach to implementing haptic interfaces involves mapping or graphing data and allowing visually impaired individuals to "feel" the data, which would then allow them to make comparisons (Brook, 1997; Fritz, et al, n.d.). Keyboards, mice, trackballs, gloves, and force feedback joysticks can be used to enable interaction with virtual environments (Durlach, et al, 1995; Srinivasan, et al, 1999). Gesturing can be interpreted from hand and eye movements, and then translated into actions performed by a computer. Gesture recognition technologies are limited by the unavailability of gesture libraries, display options for gesture data, and precision of data gathering (Hofmann, 1995; Jacob, n.d.; Shaviv, n.d.). An attempt to enable computers to recognize sign language has met with limited success, though the technology for accomplishing this has advanced greatly.
Limited vocabularies can be used to establish communication between a person and machine (Gerth, 1991; Kelly, 1975). While research in this area of interactive communication is quite limited, there are many consumer products that do this quite well. Predictive text input is one example of a limited vocabulary dialogue that is becoming very widely used, primarily for text entry via the keypads of cellular telephones.
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A-1. What are the
state-of-the-art of speech-based/natural language technologies?
The goal of speech-based/natural language technology is to provide an interface with which the user can interact through conversation without training (Martin, et al, 1996; Tanaka, 2000). While significant progress in research has been made, this goal, however, is far from being implemented in mainstream commercial products (Karat, et al, 1999; Mane, et al, 1996). Some barriers to implementation include limitations in the kind of speech recognition supported by current technology, awkward error recovery, limited speed and vocabulary size, and cost (Mane, et al, 1996). Another limitation is poor interface design (Thomas, et al, 1999). Much of the research in automatic speech recognition (ASR) technology takes place in industry labs (e.g., AT&T, IBM, Sun Microsystems), and focuses on developing interfaces that facilitate natural language dialogue between humans and machines (e.g., Boyce, 1999; Karat, et al, 1999). Another limiting factor in speech recognition is the current emphasis on sound matching; great strides are being made to add semantic knowledge to increase the accuracy of the recognition system (Barker, 2003).
The currently existing technology has been successfully implemented in commercial products that allow speech-based control, i.e., voice control (e.g., phones, household appliances, powered hospital beds, etc.) and voice interactive systems (e.g., for information services, airline reservations, or movie times) (McMillan, et al, 1997). These technologies are successful for highly constrained systems, are generally speaker-independent, and typically have an error rate of 5% or less (McMillan, et al, 1997). Voice interactive systems, as used in voicemail and interactive menus, however, are frequently inaccessible to individuals with hearing impairments (FCC, 2000; Thomas, et al, 1999).
The Speech Application Language Tags (SALT) Forum was founded in 2001. SALT expands on basic markup languages to add a speech interface to web pages. SALT also supports multi-modal access via speech, keyboard, keypad, mouse, and stylus. “By employing the SALT-based programming model and speech technology integrated into existing or new Web applications, companies can offer anyone with a telephone, PC or mobile device access to Web-based information and services” (Barker, 2003).
Barker, D. (2003). Microsoft research spawns a new era in speech technology: simpler, faster, and easier speech application development. PC AI Magazine, 16 (6), 18-27. Retrieved June 26, 2003 from the World Wide Web:
Click here to go to this resource. (http://www.pcai.com/Paid/Issues/PCAI-Online-Issues/16.6_OL/New_Folder/TLH702/16.6_PA/PCAI-16.6-Paid-pg.18-Art1.htm)
Boyce, S. (1999). Spoken natural language dialogue systems: User interface issues for the future. In D. Gardner-Bonneau (Ed.), Human factors and voice interactive systems (pp. 37-61). Norwell, MA: Kluwer Academic Publishers.
Karat, J., Lai, J., Danis, C., & Wolf, C. (1999). Speech user interface evolution. In D. Gardner-Bonneau (Ed.), Human factors and voice interactive systems (pp. 1-35). Norwell, MA: Kluwer Academic Publishers.
Mane, A., Boyce, S., Karis, D., & Yankelovich, N. (1996). Designing the user interface for speech recognition applications: A CHI workshop. SIGCHI, 28 (4). Retrieved January 16, 2001, from the World Wide Web:
Click here to go to this resource. (http://www.cwi.nl/~steven/sigchi/bulletin/1996.4/boyce.html)
Martin, P., Crabbe, F., Adams, S., Baatz, E., & Yankelovich, N. (1996, July). SpeechActs: A spoken language framework. Computer, 29 (7), 33-40. Retrieved January 16, 2001, from the World Wide Web:
Click here to go to this resource. (http://www.computer.org/computer/co1996/r7033abs.htm)
McMillan, G. R., Eggleston, R. G., & Anderson, T. R. (1997). Nonconventional controls. In G. Salvendy (Ed.), Handbook of human factors and ergonomics (pp. 729-771). New York, NY: John Wiley & Sons.
Roe, D. B., & Wilpon, J. G. (Eds.) (1994). Voice communication between humans and machines. Washington, D.C.: National Academy Press.
Tanaka, D. (2000, October 23). Speech next user interface, says IBM. Canada Computer Paper, Inc. Retrieved January 16, 2001, from the World Wide Web (link updated September 22, 2003):
Click here to go to this resource. (http://www.hubcanada.com/story_4348_20)
Thomas, J. C., Basson, S., & Gardner-Bonneau, D. (1999). Universal access and assistive technology. In D. Gardner-Bonneau (Ed.), Human factors and voice interactive systems (pp. 135-146). Norwell, MA: Kluwer Academic Publishers.
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A-2. What are the
state-of-the-art of auditory information displays?
Auditory information displays augment or substitute visual information with both speech and non-speech (environmental or abstract) sound. Several researchers note the importance of auditory information for enhancing the usability of visual information displays (such as the World Wide Web), not just for people with physiological visual impairments (Krueger & Gilden, 1997), but also for people whose vision is impaired through environmental or task constraints (Petrucci, et al, 2000; Tannen, 1998; Wynblatt, et al, 1997). The type of sound (speech, non-speech environmental, or non-speech abstract) chosen for presenting auditory information varies, depending on the goals of using the sound (e.g., improving reaction time) and the characteristics of the sound environment (e.g., the frequency with which the sound will be used) (Bussemakers & de Hann, 2000; Tannen, 1998). For example, abstract non-speech sounds appear to be more difficult to learn (Leung, et al, 1997) and may even reduce performance (Bussemakers & de Hann, 2000), though users might find them less annoying to use after repeated exposures (Bussemakers & de Hann, 2000) and easier to use than language-based auditory information (Tannen, 1998).
Despite promising progress in the area of sonification (conveying information via non-speech audio) research, there are still several barriers that must be overcome before sonification is widely used for alternative presentation of information. Some of these barriers include sonification tools that are not yet flexible enough to accommodate changes in knowledge regarding the mapping of information to sound or changes in audio hardware and software (Kramer, et al, 1997, though see Petrucci, et al, 2000). In addition, general design principles for applying sonification to particular displays have yet to be developed (Kramer, et al, 1997), though some successful initial efforts should be noted (i.e., Leplâtre & Brewster, 2000; Lumsden, et al, 2002; Mynatt, 1994). This will require interdisciplinary research among the areas of human perception, acoustics, design, the arts, and engineering (Kramer, et al, 1997).
Bussemakers, M. P., & de Haan, A. (2000). When it sounds like a duck and it looks like a dog…Auditory icons vs. earcons in multimedia environments. Proceedings of the 6th International Conference on Auditory Display. Retrieved October 7, 2003 from the World Wide Web:
Click here to go to this resource. (http://www.icad.org/websiteV2.0/Conferences/ICAD2000/PDFs/
Bussemakers.pdf)
Feworn, A., Bodner, R., & Chignell, M. H. (2000). Auditory WWW search tools. Proceedings of the 6th International Conference on Auditory Display. Retrieved October 7, 2003 from the World Wide Web:
Click here to go to this resource. (http://www.icad.org/websiteV2.0/Conferences/ICAD2000/
PDFs/FerwornBodnerChignell.pdf)
Kramer, G., Walker, B., Bonebright, T., Cook, P., Flowers, J., Miner, N., Neuhoff, J., Bargar, R., Barrass, S., Berger, J., Evreinov, G., Fitch, W. T., Grohn, M., Handel, S., Kaper, H., Levkowitz, H., Lodha, S., Shinn-Cunningham, B., Simoni, M., & Tipei, S. (1997). Sonification report: Status of the field and research agenda.
Krueger, M. W., & Gilden, D. (1997). KnowWhere: An audio/spatial interface for blind people. Proceedings of the 3rd International Conference on Auditory Display. Retrieved October 7, 2003 from the World Wide Web:
Click here to go to this resource. (http://www.icad.org/websiteV2.0/Conferences/ICAD97/
Kruger.PDF)
Leplâtre, G., & Brewster, S. A. (2000). Designing non-speech sounds to support navigation to mobile phone menus. Proceedings of the 6th International Conference on Auditory Display. Retrieved October 7, 2003 from the World Wide Web:
Click here to go to this resource. http://www.icad.org/websiteV2.0/Conferences/ICAD2000/
PDFs/Leplatre.pdf)
Leung, Y. K., Smith, S., Parker, S., & Martin, R. (1997). Learning and retention of auditory warnings. Proceedings of the 3rd International Conference on Auditory Display. Retrieved October 7, 2003 from the World Wide Web:
Click here to go to this resource. (http://www.icad.org/websiteV2.0/Conferences/ICAD97/
Leung.pdf)
Lumsden, J., Brewster, S.A., Crease, M. and Gray, P.D. (2002). Guidelines for audio-enhancement of graphical user interface widgets. Proceedings of British HCI, Vol II (pp. 6-9). London: BCS. Retrieved June 30, 2003 from the World Wide Web:
Click here to go to this resource. (http://www.dcs.gla.ac.uk/~stephen/papers/HCI2002-lumsden.pdf)
Mitsopoulos, E. N., & Edwards, A. D. N. (1997). Auditory scene analysis as the basis for designing auditory widgets. Proceedings of the 3rd International Conference on Auditory Display. Retrieved October 7, 2003 from the World Wide Web:
Click here to go to this resource. (http://www.icad.org/websiteV2.0/Conferences/ICAD97/
Mitsopoulos.pdf)
Mynatt, E. D. (1994). Designing with auditory icons: How well do we identify auditory cues? Proceedings of the CHI '94 Conference Companion. Boston.
Petrucci, L. S., Harth, E., Roth, P., Assimacopoulos, A., & Pun, T. (2000). WebSound: A generic Web sonification tool, and its application to an auditory Web browser for blind and visually impaired users. Proceedings of the 6th International Conference on Auditory Display. Retrieved October 7, 2003 from the World Wide Web:
Click here to go to this resource. (http://www.icad.org/websiteV2.0/Conferences/ICAD2000/
PDFs/PetrucciPHRAP.pdf)
Tannen, R. S. (1998). Breaking the sound barrier: Designing auditory displays for global usability. Fourth Conference on Human Factors and the Web. Retrieved January 8, 2001 from the World Wide Web:
Click here to go to this resource. (http://www.research.att.com/conf/hfweb/proceedings/tannen/)
Wynblatt, M., Benson, D., & Hsu, A. (1997). Browsing the World Wide Web in a non-visual environment. Proceedings of the 3rd International Conference on Auditory Display. Retrieved October 7, 2003 from the World Wide Web:
Click here to go to this resource. (http://www.icad.org/websiteV2.0/Conferences/ICAD97/
Wynblatt.pdf)
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A-3. What are the
state-of-the-art of haptic interfaces?
The design challenge for haptic interfaces is to simultaneously allow the manipulation of either real (as in teleoperated devices) or imagined (as in VR objects) objects that create the tactile sensation that such activity is occurring. The implications of meeting this challenge span diverse applications, such as operating remote equipment, medical training, and tactile graphics for the blind (Brook, 1997; Fritz, et al, n.d.). Research in this area to date has had a successful start in meeting this challenge (Durlach & Mavor, 1995). Current haptic interfaces that have enjoyed some success in the commercial market are position-sensing gloves (e.g., CyberTouch, SensorGloves) and exoskeletons without force-reflection (e.g., PHANToM) (Durlach & Mavor, 1995; Hofmann, 1995). In addition, a haptic interface, called TACTICS, which presents 2- and 3-dimensional graphical information through touch has recently been developed with some initial success (Fritz, et al, n.d.). While force-reflecting (ground- and body-based) interfaces simulating tactile sensations have been designed, more work must be done to improve their effectiveness (Durlach & Mavor, 1995).
Some barriers to more effective haptic interfaces include lack of knowledge about the physiology of human haptics, lack of sophisticated technology for stimulating the multitude of haptic nerves or mapping the degrees of freedom of the hand, and lack of data comparing human vs. haptic device performance (Durlach & Mavor, 1995; Srinivasan, et al, 1999).
The National Institute of Standards and Technology, in conjunction with the National Federation of the Blind, are working to develop two display technologies for use by the blind and visually impaired. The first is a rotating-wheel based refreshable Braille display, which promises to reduce the cost of refreshable Braille displays and enable high speed reading devices about the size of a portable CD player. The second is a refreshable tactile graphic display, which allows blind and visually impaired users to view ../images by touch (NIST, 2003).
Brook, D. (1997, December 6). Haptic interfaces in virtual reality. Retrieved January 16, 2001 from the World Wide Web:
Click here to go to this resource. (http://www.hpcc.ecs.soton.ac.uk/~dtcb98r/vrhap/vrhap.htm)
Durlach, N. I., & Mavor, A. S. (Eds.). (1995). Haptic interfaces. Virtual reality: Scientific and technological challenges (pp.161-187). Washington, D. C. National Academy Press.
Fritz, J. P., Way, T. P., & Barner, K. E. (n.d.). Haptic representation of scientific data for visually impaired or blind persons. Retrieved January 16, 2001, from the World Wide Web:
Click here to go to this resource. (http://www.rit.edu/~easi/easisem/haptic.html)
NIST. (2003). The NIST Rotating-Wheel Based Refreshable Braille Display. The NIST Refreshable Tactile Graphic Display. Retrieved September 25, 2003, from the World Wide Web:
Click here to go to this resource. (http://www.itl.nist.gov/div895/isis/braille.html)
Srinivasan, M. A., Basdogan, C., & Ho, C. (1999). Haptic interactions in the real and virtual worlds. In D. J. Duke & A. Puerta (Eds.), Design, specification, and verification of interactive systems ’99, (pp. 1-16). Austria: Springer-Verlag/Wien.
Go back to the top of this page.
A-4. What are the
state-of-the-art of gesture recognition technologies?
Gesture recognition technology, which holds promise for the development of hands-free interfaces, is fraught with barriers to implementation (Wexelblat, 1998). Such barriers include the lack of a comprehensive taxonomy for categorizing and interpreting classes of gestures, technology that is limited to recognizing discrete gestures, culture-specific gestures, poor communication among researchers, and technological limitations (Wexelblat, 1998). There have been some initial successful attempts to develop technology that recognizes sign language symbols, facial expressions, and sign language grammar, however (Edwards, 1998). In addition, attempts to develop interfaces that are controlled by eye movements have also achieved some success (Jacob, n.d.; Shaviv, n.d.). Barriers to implementing this technology includes technological limitations, awkward user equipment, and lack of knowledge regarding the nature of eye movements (Jacob, n.d.; Shaviv, n.d.).
Edwards, A. D. N. (1998). Progress in sign language recognition. In I. Wachsmuth & M. Fröhlich (Eds.), Gesture and sign language in human-computer interaction, Proceedings of the International Gesture Workshop, September, 1997, Bielefeld, Germany (pp. 13-21). Berlin: Springer-Verlag.
Hofmann, F. (1995, November 3). Gesture recognition with SensorGloves. Retrieved January 16, 2001, from the World Wide Web:
Click here to go to this resource. (http://pdv.cs.tu-berlin.de/forschung/IFP_engl.html)
Jacob, R. J. K. (n.d.). Eye tracking in advanced interface design. Retrieved January 8, 2001 from the World Wide Web:
Click here to go to this resource. (http://www.eecs.tufts.edu/~jacob/papers/barfield.html)
Leibe, B., Minnen, D., Weeks, J., & Starner, T. (2001). Integration of Wireless Gesture Tracking, Object Tracking, and 3D Reconstruction in the Perceptive Workbench. International Conference on Computer Vision Systems, July, 2001, Vancouver, Canada (pp. 73-92). Retrieved October 7, 2003 from the World Wide Web:
Click here to go to this resource. (http://www.vision.ethz.ch/leibe/papers/leibe-perceptive-icvs01.pdf)
Shaviv, B. D. (n.d.). The design and improvement of an eye controlled interface. Retrieved January 8, 2001 from the World Wide Web (link updated September 22, 2003):
Click here to go to this resource. (http://www.cs.sunysb.edu/~vislab/projects/eye/Reports/
report/report.pdf)
Wexelblat, A. (1998). Research challenges in gesture: Open issues and unsolved problems. In I. Wachsmuth & M. Fröhlich (Eds.), Gesture and sign language in human-computer interaction. Proceedings of the International Gesture Workshop, September, 1997, Bielefeld, Germany (pp. 1-12). Berlin: Springer-Verlag.
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A-5. What are the
state-of-the-art of interactive communication limited vocabulary dialogues?
A limited vocabulary dialogue that is becoming very widely used is “predictive text entry.” There are a number of competing technologies, including T9, iTAP, and eZiText, all of which are primarily used for text entry on telephone (typically cellular telephone) keypads. Predictive text entry allows the user to enter text by pressing one key on the keypad for each letter; as a word is entered, the phone will compare all possible letter combinations against a built-in vocabulary. If the entry cannot be mapped uniquely to a single word in the vocabulary, a list of choices is presented to the user.
Kelly, M.J. (1975). Studies in interactive communication: Limited vocabulary natural language dialogue. (ONR Contract No. N00014-75-C-0131). Baltimore, MD: John Hopkins University, Department of Psychology.
Gerth, J. (1991, July). Knowledge Acquisition. Briefing presented at Technical Coordination Meeting #2 for the Analog Circuit Analysis and Partitioning System (ACAPS), Atlanta, GA.
T9 Text Input Home Page. (n.d). How to Type on Your Phone. Retrieved from the World Wide Web September 26, 2003:
Click here to go to this resource. (http://www.t9.com/t9_learnhow.html)
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Telephone: 1-800-726-9119 (Voice/TTY) · Fax: 404-894-9320 · Email: ittatc@ittatc.org
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Center for Assistive Technology and Environmental Access
Georgia Institute of Technology
490 10th Street NW · Atlanta, GA 30318
Telephone: 1-800-726-9119 (Voice/TTY) · Fax: 404-894-9320 · Email: ittatc@ittatc.org