Enriching web information scent for blind users

ABSTRACT

Link annotation with the accessibility level of the target Web page is an adaptive navigation support technique aimed at increasing blind users' orientation in Web sites. In this work, the accessibility level of a page is measured by exploiting data from evaluation reports produced by two automatic assessment tools. These tools support evaluation of accessibility and usability guideline-sets. As a result, links are annotated with a score that indicates the conformance of the target Web page to blind user accessibility and usability guidelines. A user test with 16 users was conducted in order to observe the strategies they followed when links were annotated with these scores. With annotated links, the navigation paradigm changed from sequential to browsing randomly through the subset of those links with high scores. Even if there was not a general agreement on the correspondence between scores and user perception of accessibility, users found annotations helpful when browsing through links related to a given topic.

REFERENCES

• 1: Abou-Zahra, S., and Squillace, M. (Eds.). Evaluation and Report Language (EARL) 1.0 Schema. http://www.w3.org/TR/EARL10-Schema
• 2: Brajnik, G., and Lomuscio, R. (2007). SAMBA: a Semi-Automatic Method for Measuring Barriers of Accessibility. ACM SIGACCESS Conference on Computers and Accessibility, ASSETS'07, 43--49.
• 3: Brajnik, G. (2009). Barrier Walkthrough: Heuristic Evaluation Guided by Accessibility Barriers.http://www.dimi.uniud.it/giorgio/projects/bw/bw.html
• 4: Bigham, J., Cavender, A., Brudvik, J., Wobbrock, J., and Ladner, R. (2007). WebinSitu: a comparative analysis of blind and sighted browsing behavior. ACM SIGACCESS Conference on Computers and Accessibility, ASSETS'07, 51--58.
• 5: Bigham, J., Lau, T., and Nichols, J. (2009). TrailBlazer: Enabling Blind Users to Blaze Trails Through the Web. Intelligent User Interfaces, IUI'09, 177--186.
• 6: Caldwell, B., Cooper, M., Guarino Reid, L., and Vanderheiden, G. Web Content Accessibility Guidelines 2.0. Available at http://www.w3.org/TR/WCAG20/
• 7: Campbell C.S., and Maglio, P.P. (1999). Facilitating Navigation in Information Spaces: Road-signs on the World Wide Web. International Journal of Human-Computer Studies 50(4), 309--327.
• 8: Chisholm, W., Vanderheiden, G., and Jacobs, I. (1999). Web Content Accessibility Guidelines 1.0. http://www.w3.org/TR/WAI-WEBCONTENT/
• 9: Craig, J., Cooper, M., Pappas, L., Schwerdtfeger, R., and Seeman, L. (2009). Accessible Rich Internet Applications (WAI-ARIA) 1.0. http://www.w3.org/TR/wai-aria/
• 10: Dujmovic, J.J. (1991). Neural Networks - Concepts, Applications, and Implementations. Preferential Neural Networks, 155--206. Prentice Hall.
• 11: Dujmovic, J.J. (1996). A Method for Evaluation and Selection of Complex Hardware and Software Systems. International Computer Measurement Group Conference, 368--378.
• 12: Fukuda, K., Saito, S., Takagi, H., and Asakawa, C. (2005). Proposing new metrics to evaluate Web usability for the blind. Extended Abstracts of CHI'05, 1387--1390.
• 13: Goble, C., Harper, S. and Stevens R. (2000). The Travails of Visually Impaired Web Travellers. ACM Conference on Hypertext and Hypermedia, Hypertext'00, 1--10.
• 14: Harper, S., and Patel, N. (2005). Gist summaries for visually impaired surfers. ACM SIGACCESS Conference on Computers and Accessibility, ASSETS'05. 90--97.
• 15: Harper, S., Goble, C., and Stevens, R. (2005). Augmenting the mobility of profoundly blind Web travellers. New Review of Hypermedia and Multimedia 11(1), 103--128.
• 16: Ivory, M.Y., Yu, S., and Gronemyer, K. (2004). Search Result Exploration: A Preliminary Study of Blind and Sighted Users' Decision Making and Performance. Extended Abstracts of CHI'04, 1453--1456.
• 17: Jul, S., and Furnas, G.W. (1997). Navigation in electronic worlds: a CHI 97 Workshop. ACM SIGCHI Bulletin, 44--49.
• 18: Lazar, J., Allen, A., Kleinman, J., and Malarkey, C. (2007). What Frustrates Screen Reader Users on the Web: A Study of 100 Blind Users. International Journal of Human-Computer Interaction 22(3), 247--269.
• 19: Leporini, B., Paternò, F., and Scorcia, A. (2006). Flexible tool support for accessibility evaluation. Interacting with Computers 18(5), 869--890.
• 20: Leporini, B., and Paternò, F. (2008). Applying Web Usability Criteria for Vision-Impaired Users: does it really improve task performance? International Journal of Human-Computer Interaction 24(1), 17--47.
• 21: Mahmud, J., Borodin, Y., and Ramakrishnan, I.V. (2007). CSurf: A Context-Driven Non-Visual Web-Browser. World Wide Web Conference, WWW'07, 31--40.
• 22: Olsina, L., and Rossi, G. (2002). Measuring Web Application quality with WebQEM. IEEE Multimedia 9(4), 20--29.
• 23: Pemberton, S. (2003). The kiss of the spiderbot. interactions 10 (1), 44.
• 24: Pirolli, P., and Card, S. (1999). Information foraging. Psychological Review 106(4), 643--675.
• 25: Sullivan, T., and Matson, R. (2000). Barriers to use: usability and content accessibility on the Web's most popular sites. ACM Conference on Universal Usability, CUU'00, 139--144.
• 26: Takagi, H., Saito, S., Fukuda, K., and Asakawa, C. (2007). Analysis of navigability of Web applications for improving blind usability. ACM Transactions on Computer-Human Interaction 14(3), article 13.
• 27: Vigo, M., Arrue, M., Brajnik, G., Lomuscio, R., and Abascal, J. (2007). Quantitative Metrics for Measuring Web Accessibility. International Cross-Disciplinary Conference on Web accessibility, W4A'07,99--107.
• 28: Vigo, M., Kobsa, A., Arrue, M., and Abascal, J. (2007). User-Tailored Web Accessibility Evaluations. ACM Conference on Hypertext and Hypermedia, Hypertext'07, 95--104.
• 29: Vigo, M., Arrue, M., and Abascal, J. (2009). Enriching Information Retrieval Results with Web Accessibility Measurement. Journal of Web Engineering 8(1), 3--24.

INDEX TERMS

Primary Classification:
  H. Information Systems
  H.1 MODELS AND PRINCIPLES
      H.1.2 User/Machine Systems
          Subjects: Human factors

Additional Classification:
  H. Information Systems
  H.5 INFORMATION INTERFACES AND PRESENTATION (I.7)
      H.5.2 User Interfaces (D.2.2, H.1.2, I.3.6)
          Subjects: Evaluation/methodology

  K. Computing Milieux
  K.4 COMPUTERS AND SOCIETY
      K.4.2 Social Issues
          Subjects: Assistive technologies for persons with disabilities

General Terms:
Design, Experimentation, Human Factors, Measurement

Keywords:
adaptive navigation, blind users, information scent, web accessibility