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User-Tailored Web Accessibility Evaluations

Introduction. What's Personal Web Accessibility?

Why we need Personal Web Accessibility

Which are the current limitations for carrying out personal accessibility evaluations [automatically]?

How to address the problem

Access Environment Features Detector

A vocabulary for user profiling

(*) WCAG 1.0, MWBP 1.0, IBM Accessibility Guidelines, Web Design Guidelines for Elderly Users, IMS Guidelines for Developing Accessible Learning Applications

A vocabulary for user profiling II. Dependencies with Assistive technologies

In the evolution over the years, ATs have addressed new accessibility issues. Strict control version is necessary since several guidelines are dependent on different versions. Dependencies are grouped in two categories:

feature Jaws version dependency type WCAG 1.0 MWBP IBM elderly e-learning
frames navigation 3.71 negative 5.4.2 1.1, 12.1, 12.2 9 n/a 6.1, 6.3, 8.2
mechanisms to control auto refreshing 4.5 positive 7.4, 10.1 5.2.8 13 n/a n/a

In addition, it is necessary to infer the disability of the user from the used ATs. CC/PP files are extended with the following concepts:

A vocabulary for user profiling III. Dependencies with Delivery Context

Some examples:

Best Practice Description Concept Type Word
SCROLLING check that pictures are smaller than screen size available screen size dimension prf:ScreenSize
OBJECTS OR SCRIPTS Check script or other object support (flash, applets...) supported formats resource access:formatsSupport

A repository of machine-understandable guideline sets

Enhancing UGL with information regarding ATs and Delivery Context

Enhancing UGL with information regarding ATs and Delivery Context II

Guidelines Instantiator (GI)

Guidelines Instantiator II

Evaluation engine and accessibility measurement

Putting all togheter

  1. AT detector retrieves data from the AT database and at the same time the Delivery Context features are also obtained
  2. AT detector queries the System Registry
  3. Information regarding potential user, ATs and access device is put in the extended CC/PP profile
  4. Based on information of the profile the GI retrives guidelines from the repository. In addition slots in guidelines are filled in
  5. A web page is evaluated against the final guidelines set
  6. Accessibility Metrics are obtained from reports
  7. A user agent applies to the DOM user-adaptive modifications

Case study

web page P1 P2 P3 P4 5 7 73 73 6 13 91 94 42 130 390 405 1 1 15 15 25 26 169 173 87 150 338 338 71 88 253 274 97 131 289 300 127 209 271 328 14 24 93 100

Case Study. Discussion

Future Work and Conclusions


User-Tailored Web Accessibility Evaluations