Catálogo de publicaciones - libros

This paper proposes a method to enable visually impaired viewers to access data broadcasting content by using various accessible devices. Data broadcasting, coded in Broadcast Markup Language, has been almost inaccessible because of its usage of dynamic HTML features and lack of semantics. This method uses a template rule to transcode BML content into an accessible static description with structure and semantics. An implementation of a trial receiver system and an experiment on transcoding are described.

This paper describes the evaluation of an intuitive mobile environment controller. Through its 3D-based user interface, the PDA based controller provides the user with mobile access to her/his physical environment and ambient media. The goal of this usability evaluation is to test the performance and analyse the user acceptance of 3D-based interaction systems compared with traditional WIMP-based controllers. At first this paper describes the interaction model which has been evaluated. Then it explains the experiment and the approach of the evaluation. Finally we present and discuss our results.

To make webpages more accessible to people with disabilities, <table> tags should not be used as a means to layout document content. Therefore, to evaluate the accessibility of webpages, it should be checked whether the pages include layout-purpose <table> tags. Automated precise detection of layout-purpose <table> tags in HTML sources is still a research challenge because it requires further than simply checking whether specific tags and/or attributes of the tags are included in the sources. We propose a method for the detection that is based on machine learning. The proposed method derives a <table> tag classifier that deduces the purpose of a <table> tag: the classifier deduces whether a <table> tag is a layout-purpose one or a table-purpose one. We have developed a system that derives classification rules by ID3. The system derives a decision tree from a set of learning data (<table> tags of which the purposes are known) and classifies <table> tags in webpages under evaluation. Classification accuracy was evaluated by cross validation with 200 test data collected from the Web. Result of the evaluation revealed that 1) the tags can be roughly classified with attribute values of border, number of rows, number of tags that appear ahead of the <table> tag, and the nest of <table> tags (i.e., these attributes are more likely to appear in upper layers in decision trees), and 2) the accuracy rates are about 90% for the 200 test data.

A range of accessibility evaluation tools are available to support Web developers in producing accessible Web resources. It is important that these tools support web developers very well, so that the developers can concentrate on the tasks of Web development. In addition, the tools should enhance Web developers understanding of accessibility issues. This paper presents a usability evaluation of five entry level accessibility evaluations tools. A group heuristic evaluation was conducted, with 5 experts in usability and accessibility working through each tool together, but rating usability problems separately. The results showed that the usability of these tools is surprisingly poor and that they do not support web developers adequately in checking the accessibility of their web resources.

This paper reviews several techniques we have discovered while trying to extend the Firefox browser to support people with visual, motor, reading, and cognitive disabilities. Our goal throughout has been to find ways to make on-the-fly transformations of Web content including adjustments of text and image size, text style, line and letter spacing, text foreground color, text background color, page background removal, content linearization, and reading text aloud. In this paper, we focus primarily on the changes we make to the browser’s Document Object Model (DOM) to transform Web content. We review the kinds of approaches we have used to make DOM modifications sufficiently fast and error free. We highlight the problems posed by Web pages with a mix of static and dynamic content generated by client-side scripts and by Web pages that use both fixed and relative placement of page elements, pages of the sort we expect to see in increasingly in the future.

There are demands for improving accessibility in existing websites by enlarging text and changing the colors. Typical solutions use technologies such as ActiveX that can only run on a specific client environment. JavaScript is supported in many Web browsers, and it can be used to add new functions for improving the accessibility of existing websites. However, Web browsers prohibit JavaScript from accessing webpages of another domain, so it is difficult to improve accessibility for related websites spanning multiple domains. This paper describes a method that solves the problem.

The 2002 eEurope Action Plan advocated adoption of the WAI Content Guidelines in public EU web sites. Many of the European countries have performed web accessibility evaluations. Most of the evaluations are based on the Web Content Accessibility Guidelines from W3C/WAI. Still, a range of different evaluation methodologies and scoring schemes are deployed across the member states. This makes it hard to compare the web accessibility status between the different EU countries. The European Accessibility Internet Observatory aims to addresses this problem. The Observatory will produce automated, large scale web accessibility measurements based on which a range of monthly benchmarks will be produced and published online. In this way, the benchmarks should provide a useful input to the eAccessibility and eInclusion policy making.

This paper presents the work carried out under the umbrella of the EU-funded project BenToWeb to develop a complete XHTML 1.0 test suite for the W3C’s Web Content Accessibility Guidelines 2.0. Initial work covered the June 2005 working draft, which was subsequently updated to the April 2006 working draft (“last call”). At the time of writing, a thorough evaluation, involving end users, is being carried out.

DHTML accessibility is being standardized by W3C, which provides metadata for UI widgets commonly implemented by HMTL and JavaScript. However it is difficult to check that webpages always have correct metadata according to the standards of DHTML accessibility since UI widgets can be updated by JavaScript programs. Thus we propose a technique for checking accessibility of UI widgets. In this check, we use static program analysis techniques so that we can check accessibility without executing a program. In addition, we developed a prototype system based on the proposed technique and applied it to a simple DHTML application.

Checking of web accessibility can be carried out in several ways along the same international standards and depending on the scale, the quality, availability of tools and the interpretation method that is followed. The Unified Web Evaluation Methodology is developed by European expert organizations and offers test descriptions to evaluate WCAG 1.0 conformance covering level AA, a clear sampling scheme, improved aggregations supporting confidence levels, Score cards and other instruments to help communicate the results of evaluations clearer and on more levels. The aim is to establish the UWEM as the basis for web accessibility evaluation, policy support and possible certification in Europe.