Dynamic Context Adaptation: a Formal Framework

Multimedia documents are collections of media objects, synchronized by means of sets of temporal and spatial constraints. Any multimedia document definition is valid as long as the referred media objects are available and the constraints are satisfiable. Document validity depends on the context in which the document has to be presented. Adaptation techniques are used when a document is not properly presentable in a given context. They adjust the document specification and return a version of the document that satisfies to the best both the author’s specifications, given the current context. In this paper, we introduce a formal framework to characterize context adaptation, in the presence of both physical and user oriented context requirements. We formally characterize undeliverable fragments of a document and define semantically equivalent presentation fragments as alternative to undeliverable ones. In the absence of equivalence, undeliverable media are replaced with candidates that minimize the loss of information/quality in the presentation.