Declarative Mark-Up Language as a Tool for Developing Educational Hypermedia

Web ever-growing generalization and its use in educational settings is impelling the development of high-quality educational hypermedia applications. Hypermedia systems complexity has promoted the use of abstract hypermedia models to capture the most relevant characteristics of these systems. Current models put the stress on hypermedia components and its hyperlinking structure (e.g. Dexter Model), on-screen presentation (e.g. Amsterdam Model), or on the adaptation of the contents to specific users (e.g. adaptive hyperbooks). These models usually do not address specific aspects that are crucial in the design and maintenance of educational hypermedias, such as the structure and content of the individual components, the structural relations between them, and the conceptual model or educational strategy underlying the application. In our work, we use a descriptive specification, based on the Standard General Mark-up Language (SGML), to simplify the design, development and maintenance of educational hypermedia. We use an SGML based specification for modeling two main aspects of a hypermedia educational application: a) the organization and structure of the application contents, and b) a description that explicitly captures relevant design decisions about presentation and educational features. This kind of description, a "document type definition" in SGML terminology, provides clear and useful design documents that easily relate the work of designers and programmers partially achieving software and platform independence. Also, the specific information about contents simplifies its adaptation to individual users based on an explicit user model. This approach has been used in the development of a hypermedia system designed for teaching text comprehension in a foreign language.