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Datalog is one of the best-known rule-based languages, and extensions of it are used in a wide context of applications. An important Datalog extension is Disjunctive Datalog, which significantly increases the expressivity of the basic language. Disjunctive Datalog is useful in a wide range of applications, ranging from Databases (e.g., Data Integration) to(More)
Datalog∃ is the extension of Datalog, allowing existentially quantified variables in rule heads. This language is highly expressive and enables easy and powerful knowledge-modeling, but the presence of existentially quantified variables makes reasoning over Datalog∃ undecidable, in the general case. The results in this paper enable powerful, yet decidable(More)
A <i>distributed XML document</i> is an XML document that spans several machines or Web repositories. We assume that a distribution design of the document tree is given, providing an XML tree some of whose leaves are "docking points", to which XML subtrees can be attached. These subtrees may be provided and controlled by peers at remote locations, or may(More)
Datalog∃ is the extension of Datalog allowing existentially quantified variables in rule heads. This language is highly expressive and enables easy and powerful knowledge-modelling, but the presence of existentially quantified variables makes reasoning over Datalog∃ undecidable in the general case. Restricted classes of Datalog∃, such as Shy, have been(More)
OBJECTIVE To compare plasma lipids in preterm infants given a new lipid emulsion containing 10% fish oil, 50% medium-chain triacylglycerols, and 40% soybean oil, compared with a standard preparation containing 50:50 medium-chain triacylglycerols: soybean oil. STUDY DESIGN Preterm infants weighing <1250 g at birth (n=47) were randomly assigned to receive(More)
The paper describes HıLεX, a new ASP-based system for the extraction of information from unstructured documents. Unlike previous systems, which are mainly syntactic, HıLεX combines both semantic and syntactic knowledge for a powerful information extraction. In particular, the exploitation of background knowledge, stored in a domain ontology, allows to(More)
In this paper we present a successful application of logic programming for e-tourism: the IDUM system. The system exploits two technologies that are based on the state-of-the-art computational logic system DLV: (i) a system for ontology representation and reasoning, called OntoDLV; and, (ii) HıLεX a semantic information-extraction tool. The core of IDUM is(More)
In this paper, a new technique for the optimization of (partially) bound queries over disjunctive Datalog programs with stratified negation is presented. The technique exploits the propagation of query bindings and extends the Magic Set optimization technique (originally defined for non-disjunctive programs). An important feature of disjunctive Datalog(More)