73,685 research outputs found
Conjunctive queries with negation over DL-Lite: a closer look
No full textWhile conjunctive query (CQ) answering over DL-Lite has been studied extensively, there have been few attempts to analyse CQs with negated atoms. This paper deepens the study of the problem. Answering CQs with safe negation and CQs with a single inequality over DL-Lite with role inclusions is shown to be undecidable, even for a fixed TBox and query.Without role inclusions, answering CQs with one inequality is P-hard and with two inequalities CoNP-hard in data complexity
DL-lite with attributes and datatypes
No full textWe extend the DL-Lite languages by means of attributes and datatypes. Attributes -- a notion borrowed from data models -- associate concrete values from datatypes to abstract objects and in this way complement roles, which describe relationships between abstract objects. The extended languages remain tractable (with a notable exception) even though they contain both existential and (a limited form of) universal quantification. We present complexity results for two most important reasoning problems in DL-Lite: combined complexity of knowledge base satisfiability and data complexity of positive existential query answering
Reasoning with Large A-Boxes in Fuzzy Description Logics using DL reasoners: An Experimental Evaluation
No full textCimiano P, Haase P, Ji Q, et al. Reasoning with Large A-Boxes in Fuzzy Description Logics using DL reasoners: An Experimental Evaluation. In: Proceedings of the ESWC Workshop on Advancing Reasoning on the Web: Scalability and Commonsense. 2008
On queries with inequalities in DL-LiteR≠
No full textIt is well-known that answering conjunctive queries with inequalities (CQ≠s) over DL-LiteR ontologies is in general undecidable. In this paper we consider the subclass of CQ≠s, called CQ≠,bs, where inequalities involve only distinguished variables or individuals. In particular, we tackle the problem of answering C≠,bs and unions thereof (UC≠,bs s) over DL-LiteR≠ ontologies, where DL-LiteR≠ corresponds to DL-LiteR without the Unique Name Assumption, and with the possibility of asserting inequalities between individuals, as in OWL 2 QL. As a first contribution, we show that answering CQ≠,bs over DL-LiteR≠ ontologies has the same computational complexity as the UCQ case over DL-LiteR, i.e., it is in AC0 in data complexity, in PTIME in TBox complexity, and NP-complete in combined complexity. We then deal with the UCQ≠b case, and prove that answering UCQ=≠b over DL-LiteR≠ ontologies is still in AC0 in data complexity and in PTIME in TBox complexity, but is Π2p-hard in combined complexity
A Metamodel for Annotations of Ontology Elements in OWL DL
No full textVrandecic D, Völker J, Haase P, Tran DT, Cimiano P. A Metamodel for Annotations of Ontology Elements in OWL DL. In: Brockmans S, Jung J, Sure Y, eds. Proceedings of the 2nd Workshop on Ontologies and Meta-Modeling, WoMM 2006. LNI, 96. GI Gesellschaft für Informatik; 2006: 109-123
dl-paGFP
No full textAll lsm files (images taken with a Zeiss 710) of dl-paGFP embryos used in the analysis (quantitative or qualitative) in this paper
Extending DL-LiteR TBoxes with view definitions
No full textViews are a mechanisms for precomputing answers to query of particular significance. Views have a definition (the query itself) and an extension obtained by evaluating the query over the data sources. Views are used for controlling the access to data and keep data even when the original sources are not accessible anymore. In this paper we introduce views definitions in DL-LiteR ontologies as an additional form of assertions in the TBox, and we study the basic reasoning tasks involving them, including consistency, containment, disjointness, projection classification, and query answering
AMČR - dokument C-DL-200900256
No full textStav: 3Označení: Bezděz - Dokeská pahorkatina, 2.JPG (M. Gojda)Popis: Hora Bezděz a Břehyňský rybník.Poznámka: Duplicitní foto C-DL-200900257 (Bezděz - Dokeská pahorkatina, 3) bylo smazáno
AMČR - dokument C-DL-200900258
No full textStav: 3Označení: Bezděz (CL), 29.JPG (M. Gojda)Popis: Hrad Bezděz.Poznámka: Duplicitní foto C-DL-200900259 (Bezděz (CL), 30) bylo smazáno
AMČR - dokument C-DL-201300717
No full textStav: 3Označení: Mariánská Týnice 16.JPG (M. Gojda)Popis: Probošství Mariánská Týnice a poutní místo. Krajina Plaské pahorkatiny.Poznámka: Duplicitní foto C-DL-201300707 (Mariánská Týnice (PS), 16) bylo smazáno
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