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Query Answering in Inconsistent Databases

by Leopoldo Bertossi, Jan Chomicki , 2003
"... In this chapter, we summarize the research on querying inconsistent databases we have been conducting over the last five years. The formal framework we have used is based on two concepts: repair and consistent query answer. We describe different approaches to the issue of computing consistent query ..."
Abstract - Cited by 367 (69 self) - Add to MetaCart
In this chapter, we summarize the research on querying inconsistent databases we have been conducting over the last five years. The formal framework we have used is based on two concepts: repair and consistent query answer. We describe different approaches to the issue of computing consistent query

Data Exchange: Semantics and Query Answering

by Ronald Fagin, Phokion G. Kolaitis, Renee J. Miller, Lucian Popa - In ICDT , 2003
"... Data exchange is the problem of taking data structured under a source schema and creating an instance of a target schema that reflects the source data as accurately as possible. In this paper, we address foundational and algorithmic issues related to the semantics of data exchange and to query answe ..."
Abstract - Cited by 427 (41 self) - Add to MetaCart
to compute a canonical universal solution efficiently. We adopt the notion of "certain answers" in indefinite databases for the semantics for query answering in data exchange. We investigate the computational complexity of computing the certain answers in this context and also study the problem

Query Answering for OWL-DL with Rules

by Boris Motik, Ulrike Sattler, Rudi Studer - Journal of Web Semantics , 2004
"... Both OWL-DL and function-free Horn rules are decidable fragments of first-order logic with interesting, yet orthogonal expressive power. A combination of OWL-DL and rules is desirable for the Semantic Web; however, it might easily lead to the undecidability of interesting reasoning problems. Here, w ..."
Abstract - Cited by 329 (28 self) - Add to MetaCart
, we present a decidable such combination where rules are required to be DL-safe: each variable in the rule is required to occur in a non-DL-atom in the rule body. We discuss the expressive power of such a combination and present an algorithm for query answering in the related logic SHIQ extended

Tractable reasoning and efficient query answering in description logics: The DL-Lite family

by Diego Calvanese, G. De Giacomo, Domenico Lembo, Maurizio Lenzerini, Riccardo Rosati - J. OF AUTOMATED REASONING , 2007
"... We propose a new family of Description Logics (DLs), called DL-Lite, specifically tailored to capture basic ontology languages, while keeping low complexity of reasoning. Reasoning here means not only computing subsumption between concepts, and checking satisfiability of the whole knowledge base, b ..."
Abstract - Cited by 497 (123 self) - Add to MetaCart
, but also answering complex queries (in particular, unions of conjunctive queries) over the instance level (ABox) of the DL knowledge base. We show that, for the DLs of the DL-Lite family, the usual DL reasoning tasks are polynomial in the size of the TBox, and query answering is LogSpace in the size

Progressive Semantic Query Answering

by Giorgos Stamou, Despoina Trivela, Ros Chortaras
"... Abstract. Ontology-based semantic query answering algorithms suffer from high computational complexity and become impractical in most cases that OWL is used as a framework for data access in the Semantic Web. For this reason, most semantic query answering systems prefer to lose some possible correct ..."
Abstract - Cited by 1 (1 self) - Add to MetaCart
Abstract. Ontology-based semantic query answering algorithms suffer from high computational complexity and become impractical in most cases that OWL is used as a framework for data access in the Semantic Web. For this reason, most semantic query answering systems prefer to lose some possible

Approximate XML Query Answers

by Neoklis Polyzotis, Minos Garofalakis, Yannis Ioannidis - In SIGMOD , 2004
"... The rapid adoption of XML as the standard for data representation and exchange foreshadows a massive increase in the amounts of XML data collected, maintained, and queried over the Internet or in large corporate datastores. Inevitably, this will result in the development of on-line decision support ..."
Abstract - Cited by 51 (3 self) - Add to MetaCart
systems, where users and analysts interactively explore large XML data sets through a declarative query interface (e.g., XQuery or XSLT). Given the importance of remaining interactive, such on-line systems can employ approximate query answers as an effective mechanism for reducing response time

On the Decidability of Consistent Query Answering

by Marcelo Arenas, Leopoldo Bertossi
"... Abstract. Consistent query answering (CQA) is about formally characterizing and computing semantically correct answers to queries posed to a database that may fail to satisfy certain integrity constraints. In this paper, we revisit the decidability status of consistent query answering by considering ..."
Abstract - Cited by 2 (0 self) - Add to MetaCart
Abstract. Consistent query answering (CQA) is about formally characterizing and computing semantically correct answers to queries posed to a database that may fail to satisfy certain integrity constraints. In this paper, we revisit the decidability status of consistent query answering

Data complexity of query answering in description logics

by Diego Calvanese, Giuseppe De Giacomo, Domenico Lembo, Maurizio Lenzerini, Riccardo Rosati - IN PROC. OF KR 2006 , 2006
"... In this paper we study data complexity of answering conjunctive queries over Description Logic knowledge bases constituted by an ABox and a TBox. In particular, we are interested in characterizing the FOL-reducibility and the polynomial tractability boundaries of conjunctive query answering, dependi ..."
Abstract - Cited by 208 (77 self) - Add to MetaCart
In this paper we study data complexity of answering conjunctive queries over Description Logic knowledge bases constituted by an ABox and a TBox. In particular, we are interested in characterizing the FOL-reducibility and the polynomial tractability boundaries of conjunctive query answering

View-Based Query Answering . . .

by Diego Calvanese, Guiseppe De Giacomo, Maurizio Lenzerini, Riccardo Rosati , 2008
"... View-based query answering is the problem of answering a query based only on the answers precomputed for a set of views. While this problem has been widely investigated in databases, it is largely unexplored in the context of Description Logic ontologies. Differently from traditional databases, Desc ..."
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View-based query answering is the problem of answering a query based only on the answers precomputed for a set of views. While this problem has been widely investigated in databases, it is largely unexplored in the context of Description Logic ontologies. Differently from traditional databases

Consistent query answering in databases

by Leopoldo Bertossi
"... ..."
Abstract - Cited by 71 (20 self) - Add to MetaCart
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Results 1 - 10 of 9,360