Abstract

The aim of this paper is to make a case generally for an ontology for accessibility requirements specification. Requirements specification is generally intended to provide clear, testable descriptions of what a system should do. What an ontology would do is to act like a requirements bank that provides methodology independent accessibility requirements that could then be used to extrapolate, on demand, conceptual models for a variety of implementations driven by a variety of methodologies. The effect of this would be to minimise requirements specification, ensure declarativity, standardisation, interoperability and reusability, whilst at the same time lending greater migratability from specification to design.

There has been much worldwide action in developing guidelines, tools and methods in an attempt to ensure that technologies and information systems are accessible. There is, however, a growing need to partner these initiatives more closely with software engineering traditions. An ontology for accessibility requirements would provide formal semantic specifications beyond the syntactic provisions rendered by commonly used formal specification languages.

Author Keywords: Accessibility; Requirements specification; Ontology; Methodology

Article Outline

Executive brief

1. Introduction

2. Guidelines, tools and technologies

2.1. Legislative and standards initiatives

2.2. Industry initiatives

2.2.1. Accessibility engineering—multiple structures

2.2.2. Single versions—universal design

2.2.3. A growing emphasis on adaptive programming and intelligent services

3. Accessibility requirements specification

3.1. Traditional requirements engineering methods: a place for accessibility

3.1.1. Disciplinary attempts at abstraction of requirements from user traits

3.1.2. Towards a greater focus on user trait abstraction

3.1.3. Towards a unified approach for accessibility requirements specification

3.2. Why then do we need an ontology?

3.3. Interaction description BNF usage example adapted from Preece (1993)

4. Ontologies: a theoretic description

4.1. So is it just a schema that we are after?

4.2. Ontologically based methodologies

4.3. AccessOnto: proposed implementation

4.4. Paradigm shifts and ontological expression

5. Conclusion

Web references

Accessibility High Browsers and text-enhancers

Web evaluation toolkits

Accessibility legislation and standards

References