In this paper, we present the virtual knowledge graph (VKG) paradigm for data integration
and access, also known in the literature as Ontology-based Data Access. Instead of …

We present Ontop, an open-source Ontology-Based Data Access (OBDA) system that allows
for querying relational data sources through a conceptual representation of the domain of …

Ontologies provide a conceptualization of a domain of interest. Nowadays, they are typically
represented in terms of Description Logics (DLs), and are seen as the key technology used …

Abstract An Introduction to Ontology Engineering is a free online textbook that provides an
overview of ontology engineering, including logics and automated reasoning, methods and …

The QL profile of OWL 2 has been designed so that it is possible to use database technology
for query answering via query rewriting. We present a comparison of our resolution based …

Value creation in an organisation is a time-sensitive and data-intensive process, yet it is
often delayed and bounded by the reliance on IT experts extracting data for domain experts …

Studies aimed at ensuring semantic access to databases have a long history and originated
at early stages of database technology development. Unfortunately, they have not led yet to …

An incomplete database is defined by a set of constraints and a partial database instance
[1]. Answering conjunctive queries over incomplete databases is an important computational …

Large language models (LLMs) have shown significant achievements in solving a wide
range of tasks. Recently, LLMs' capability to store, retrieve and infer with symbolic …

Mega-urbanization presents researchers with a network of densely interwoven problems
that completely elude disciplinary boundaries. We report on the development of a spatial …