Abstract
This paper discusses the design challenges encountered when building an ontology repository for an application framework devoted to assistive technologies that can be browsed and queried in a highly heterogeneous and expressive way. As a main vehicle to achieve this goal we propose to use metadata and meta-reasoning. We analyze how metadata can be used in the context of open repositories of ontologies, and how it can and needs to be extended in various ways. In particular we study a redesign of the Ontology Metadata Vocabulary OMV by restructuring and enriching it with the ABC ontology and domain-specific categories for assistive technologies. Examples of an elderly assistance system illustrate how this extended OMV can support more sophisticated reasoning and querying over repositories of ontologies for assistive applications.