We present the framework of ontology-based data access, a semantic paradigm for
providing a convenient and user-friendly access to data repositories, which has been …

We introduce the query-by-example (QBE) paradigm for query answering in the presence of
ontologies. Intuitively, QBE permits non-expert users to explore the data by providing …

The proliferation of heterogeneous data sources in many application contexts brings an
urgent need for expressive and efficient data integration mechanisms. There are strong …

In this paper, we study how to efficiently integrate multiple relational databases using an
ontology-based approach. In ontology-based data integration (OBDI) an ontology provides a …

We investigate ontology-based data access to temporal data. We consider temporal
ontologies given in linear temporal logic LTL interpreted over discrete time (Z,<). Queries are …

Any attempt at a tight integration between semantic technologies and object oriented
programming will invariably stumble over the gap between the two underlying object …

Aiming to understand the data complexity of answering conjunctive queries mediated by an
axiom stating that a class is covered by the union of two other classes, we show that …

Conjunctive Query (CQ) answering is a primary reasoning task over knowledge bases.
However, when considering expressive description logics, query answering can be …

Massive ocean data acquired by various observing platforms and sensors poses new
challenges to data management and utilization. Typically, it is difficult to find the desired data …

We develop a flexible, open-source framework for query answering on relational databases
by adopting methods and techniques from the Semantic Web community and the data …