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Auflistung nach Schlagwort "Query answering"

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  • Zeitschriftenartikel
    Abductive Conjunctive Query Answering w.r.t. Ontologies
    (KI - Künstliche Intelligenz: Vol. 30, No. 2, 2016) Möller, Ralf; Özçep, Özgür; Haarslev, Volker; Nafissi, Anahita; Wessel, Michael
    In this article we investigate abductive conjunctive query answering w.r.t. ontologies and show how use cases can benefit from this kind of query answering service. While practical reasoning systems such as Racer have supported abductive conjunctive query answering for 10 years now, and many projects have exploited this feature, few publications deal with A-box abduction from an implementation perspective. This article gives a generalized overview on features provided by practical systems and also explains optimization techniques needed to meet practical requirements.
  • Zeitschriftenartikel
    NoHR: An Overview
    (KI - Künstliche Intelligenz: Vol. 34, No. 4, 2020) Kasalica, Vedran; Knorr, Matthias; Leite, João; Lopes, Carlos
    Description logic ontologies, such as ontologies written in OWL, and non-monotonic rules, as known in Logic Programming, are two major approaches in Knowledge Representation and Reasoning. Even though their integration is challenging due to their inherent differences, the need to combine their distinctive features stems from real world applications. In this paper, we give an overview of NoHR, a reasoner designed to answer queries over theories composed of an OWL ontology in a Description logic and a set of non-monotonic rules. NoHR has been developed as a plug-in for the widely used ontology editor Protégé, building on a combination of reasoners dedicated to OWL and rules, but it is also available as a library, allowing for its integration within other environments and applications. It comes with support for all polynomial OWL profiles and the integration of their constructors as well as for standard built-in Prolog predicates, and allows the direct consultation of databases during query evaluation and the usage of sophisticated mechanisms, such as tabling already computed results, all of which enhances the applicability and the efficiency of query answering.
  • Zeitschriftenartikel
    Querying Rich Ontologies by Exploiting the Structure of Data
    (KI - Künstliche Intelligenz: Vol. 34, No. 3, 2020) Bajraktari, Labinot
    Ontology-based data access (OBDA) has emerged as a paradigm for accessing heterogeneous and incomplete data sources. A fundamental reasoning service in OBDA, the ontology mediated query (OMQ) answering has received much attention from the research community. However, there exists a disparity in research carried for OMQ algorithms for lightweight DLs which have found their way into practical implementations, and algorithms for expressive DLs for which the work has had mainly theoretical oriented goals. In the dissertation, a technique that leverages the structural properties of data to help alleviate the problems that typically arise when answering the queries in expressive settings is developed. In this paper, a brief summary of the technique along with the different algorithms developed for OMQ for expressive DLs is given.