Now showing items 1-20 of 24

    • Adding Weight to DL-Lite 

      Artale A; Calvanese D; Kontchakov R; Zakharyaschev M (CEUR-WS.org, 2009)
      In this paper we extend the logic DL-LiteNbool and its fragments with (i) role inclusions, (ii) qualified number restrictions and (iii) role disjointness, symmetry, asymmetry, reflexivity and irreflexivity constraints. We ...
    • The Complexity of Clausal Fragments of LTL 

      Artale A; Kontchakov R; Ryzhikov V; Zakharyaschev M (Springer, 2013)
      We introduce and investigate a number of fragments of propositional temporal logic LTL over the flow of time (Z, <). The fragments are defined in terms of the available temporal operators and the structure of the clausal ...
    • Complexity of reasoning over entity-relationship models? 

      Artale A; Calvanese D; Kontchakov R; Ryzhikov V; Zakharyaschev M (Bozen-Bolzano University Press, 2007)
      We investigate the complexity of reasoning over various fragments of the Extended Entity-Relationship (EER) language, which include different combinations of the constructors for ISA between concepts and relationships, ...
    • Complexity of Reasoning over Temporal Data Models 

      Artale A; Kontchakov R; Ryzhikov V; Zakharyaschev M (Springer, 2010)
      We investigate the computational complexity of reasoning over temporal extensions of conceptual data models. The temporal conceptual models we analyse include the standard UML/EER constructs, such as isa between entities ...
    • Connecting Abstract Description Systems 

      Kutz O; Wolter F; Zakharyaschev M (Morgan Kaufmann, 2002)
    • Correcting Access Restrictions to a Consequence More Flexibly 

      Eldora; Knechtel M; Peñaloza R (CEUR, 2011)
      Recent research has shown that labeling ontologies can be useful for restricting the access to some of the axioms and their implicit consequences. However, the labeling of the axioms is an error-prone and highly sensible ...
    • DL-Lite in the light of first-order logic 

      Artale A; Calvanese D; Kontchakov R; Zakharyaschev M (AAAI Press, 2007)
      The use of ontologies in various application domains, such as Data Integration, the Semantic Web, or ontology-based data management, where ontologies provide the access to large amounts of data, is posing challenging ...
    • DL-Lite with Attributes and Sub-Roles (Extended Abstract) 

      Artale A; Ibáñez-García A; Kontchakov R; Ryzhikov V (CEUR-WS.org, 2011)
    • DL-Lite with Temporalised Concepts, Rigid Axioms and Roles 

      Artale A; Kontchakov R; Ryzhikov V; Zakharyaschev M (Springer, 2009)
      We investigate the temporal extension of the description logic extslDL−Lite(RN)bool with the until operator on concepts, rigid (time-independent) and local (time-dependent) roles, and rigid TBox axioms. Using an embedding ...
    • First-Order Rewritability of Temporal Ontology-Mediated Queries 

      Artale A; Kontchakov R; Kovtunova A; Ryzhikov V; Wolter F; Zakharyaschev M (AAAI Press, 2015)
      Aiming at ontology-based data access over temporal, in particular streaming data, we design a language of ontology-mediated queries by extending OWL 2 QL and SPARQL with temporal operators, and investigate rewritability ...
    • Fuzzy Ontologies over Lattices with T-norms 

      Borgwardt S; Peñaloza R (CEUR, 2011)
    • Interval temporal description logics 

      Artale A; Kontchakov R; Ryzhikov V; Zakharyaschev M (CEUR, 2015)
      We design interval temporal description logics based on the Horn fragment of DL-Lite extended with the Allen temporal operators. We identify two tractable fragments that are expressive enough to represent constraints arising ...
    • Metric Temporal Logic for Ontology-Based Data Access over Log Data 

      Calvanese D; Guzel Kalaycı E; Ryzhikov V; Xiao G; Zakharyaschev M (IJCAI Workshop 40, 2016)
      We present a new metric temporal logic HornMTL over dense time and its datalog extension datalogMTL. The use of datalogMTL is demonstrated in the context of ontology-based data access over meteorological data. We show ...
    • Ontology-Based Data Access: A Survey 

      Xiao G; Calvanese D; Kontchakov R; Lembo D; Poggi A; Rosati R; Zakharyaschev M (IJCAI Organization, 2018)
      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 actively developed and studied in the past decade.  ...
    • Ontology-Mediated Query Answering over Temporal Data: A Survey 

      Artale A; Kontchakov R; Kovtunova A; Ryzhikov R; Wolter F; Zakharyaschev M (Schloss Dagstuhl - Leibniz-Zentrum für Informatik GmbH, Dagstuhl Publishing, 2017)
      We discuss the use of various temporal knowledge representation formalisms for ontology-mediated query answering over temporal data. In particular, we analyse ontology and query languages based on the linear temporal logic ...
    • Past and Future of DL-Lite 

      Artale A; Kontchakov R; Ryzhikov V; Zakharyaschev M (AAAI Press, 2010)
      We design minimal temporal description logics that are capa- ble of expressing various aspects of temporal conceptual data models and investigate their computational complexity. We show that, depending on the required types ...
    • Query-Based Entailment and Inseparability for ALC Ontologies 

      Botoeva E; Lutz C; Ryzhikov V; Wolter F; Zakharyaschev M (AAAI Press, 2016)
      We investigate the problem whether two ALC knowledge bases are indistinguishable by queries over a given vocabulary. We give model-theoretic criteria and prove that this problem is undecidable for conjunctive queries (CQs) ...
    • Reasoning over Extended ER Models 

      Artale A; Calvanese D; Kontchakov R; Ryzhikov V; Zakharyaschev M (Springer, 2007)
      We investigate the computational complexity of reasoning over various fragments of the Extended Entity-Relationship (EER) language, which includes a number of constructs: isa between entities and relationships, disjointness ...
    • The Semantics of Modal Predicate Logic I: Counterpart-Frames 

      Kracht M; Kutz O (World Scientific, 2002)
      We introduce a new semantics for modal predicate logic, with respect to which a rich class of first-order modal logics is complete, namely all normal first-order modal logics that are extensions of free quantified K. This ...