Temporalizing Ontology-Based Data Access

Abstract

Abstract. Ontology-based data access (OBDA) generalizes query answering in databases towards deduction since (i) the fact base is not assumed to contain complete knowledge (i.e., there is no closed world assumption), and (ii) the interpretation of the predicates occurring in the queries is constrained by axioms of an ontology. OBDA has been investigated in detail for the case where the ontology is expressed by an appropriate Description Logic (DL) and the queries are conjunctive queries. Motivated by situation awareness applications, we investigate an extension of OBDA to the temporal case. As query language we consider an extension of the well-known propositional temporal logic LTL where conjunctive queries can occur in place of propositional variables, and as ontology language we use the prototypical expressive DL ALC. For the resulting instance of temporalized OBDA, we investigate both data complexity and combined complexity of the query entailment problem.

Practical Querying of Temporal Data via OWL 2 QL and SQL:2011

“…In this respect, it is highly desirable to establish stronger links between the approach pursued here and those proposed recently in [3,5,2], with the prospect of gaining a clearer view on the landscape of technical possibilities regarding the temporal OBDA.…”

“…The language TQL, presented in this section, is defined using a generic construction method for temporal query languages in DLs, explored in [10,3,5]. TQL is a combination of a temporal language with CQs, obtained by substituting CQs for the atoms in temporal formulas.…”

“…The research on temporal extensions to OBDA has been taken up only very recently by Borgwardt et al [3,5] and Artale et al [2]. In [3], the authors study the same prototypical scenario as addressed here, but focus on its more foundational aspects.…”

“…In [3], the authors study the same prototypical scenario as addressed here, but focus on its more foundational aspects. They consider a more expressive DL ALC as the background ontology language and adopt a less restrictive definition of temporal queries.…”

Temporal Query Answering in DL-Lite with Negation

“…The temporal query language we focus on has originally been proposed in [9] for querying knowledge bases in ALC. The queries are propositional LTL formulas in which the propositions have been replaced by CQs.…”