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DEXA
2009
Springer
14 years 2 months ago
2009
Springer
Describing relational data sources (i.e. databases) by means of ontologies constitutes the foundation of most of the semantic based approaches to data access and integration. In sp...
ICDT
2010
ACM
14 years 4 months ago
2010
ACM
It is known that the composition of schema mappings, each specified by source-to-target tgds (st-tgds), can be specified by a secondorder tgd (SO tgd). We consider the question of...
ECAI
1998
Springer
13 years 11 months ago
1998
Springer
Abstract. We extend different Description Logics by concrete domains (such as integers and reals) and by aggregation functions over these domains (such as min;max;count;sum), which...
VLDB
2005
ACM
14 years 28 days ago
2005
ACM
In recent years, publish-subscribe (pub-sub) systems based on XML document filtering have received much attention. In a typical pubsub system, subscribed users specify their inte...
ICCS
2009
Springer
14 years 2 months ago
2009
Springer
Abstract. In knowledge bases, the open world assumption and the ability to express variables may lead to an answer redundancy problem. This problem occurs when the returned answers...