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First-order mu-calculus over Generic Transition Systems and Applications to the Situation Calculus
(2018)We consider muL, muLa, and muLp, three variants of the first-order mu-calculus studied in verification of data-aware processes, that differ in the form of quantification on objects across states. Each of these three logics ... -
Ontop: Answering SPARQL queries over relational databases
(2017)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 interest, provided in terms of an ontology, ... -
Tractability and intractability of controlled languages for data access
(2012)In this paper we study the semantic data complexity of several controlled fragments of English designed for natural language front-ends to OWL (Web Ontology Language) and description logic ontology-based systems. Controlled ... -
View-based query answering in description logics: Semantics and complexity
(2012)View-based query answering is the problem of answering a query based only on the precomputed answers to a set of views. While this problem has been widely investigated in databases, it is largely unexplored in the context ... -
Ontology-Based Access To Temporal Data With Ontop: A Framework Proposal
(2019)Predictive analysis gradually gains importance in industry. For instance, service engineers at Siemens diagnostic centres unveil hidden knowledge in huge amounts of historical sensor data and use this knowledge to improve ... -
Research Directions for Principles of Data Management (Abridged)
(2016)In April 2016, a community of researchers working in the area of Principles of Data Management (PDM) joined in a workshop at the Dagstuhl Castle in Germany. The workshop was organized jointly by the Executive Committee of ... -
Capturing model-based ontology evolution at the instance level: The case of DL-Lite
(2013)Evolution of Knowledge Bases (KBs) expressed in Description Logics (DLs) has gained a lot of attention lately. Recent studies on the topic have mostly focused on so-called model-based approaches (MBAs), where the evolution ... -
Data complexity of query answering in description logics
(2013)In this paper we study data complexity of answering conjunctive queries over Description Logic (DL) knowledge bases constituted by an ABox and a TBox. In particular, we are interested in characterizing the FOL-rewritability ... -
Query Processing under GLAV Mappings for Relational and Graph Databases
(2012)Schema mappings establish a correspondence between data stored in two databases, called source and target respectively. Query processing under schema mappings has been investigated extensively in the two cases where each ...
