Towards a Unifying Approach to Representing and Querying Temporal Data in Description Logics

Abstract

Establishing a generic approach to representing and querying temporal data in the context of Description Logics (DLs) is an important, and still open challenge. The difficulty lies in that a proposed approach should reconcile a number of valuable contributions coming from diverse, yet relevant research lines, such as temporal databases and query answering in DLs, but also temporal DLs and Semantic Web practices involving rich temporal vocabularies. Within such a variety of influences, it is critical to carefully balance theoretical foundations with good prospects for reusing existing techniques, tools and methodologies. In this paper, we attempt to make first steps towards this goal. After providing a comprehensive overview of the background research and identifying the core requirements, we propose a general mechanism of defining temporal query languages for time-stamped data in DLs, based on combinations of linear temporal logics with first-order queries. Further, we advocate a controlled use of epistemic semantics in order to warrant practical query answering. We systematically motivate our proposal and highlight its basic theoretical and practical implications. Finally, we outline open problems and key directions for future research.