Salvador Abreu

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Universidade de Évora’s Integrated Information System (SIIUE) aims at representing the entire universe of concepts useful for the management and day-to-day operation of the Organization, as seen from the point of view of several different classes of users. It relies on ISCO, a logic programming language geared towards the development and maintenance of(More)
The current proposals for the inclusion of modules in the ISO Prolog standard are not very consensual. Since a program-structuring feature is required for a production programming language, several alternatives have been explored over the years. In this article we recall and expand on the concepts of Contextual Logic Programming, a powerful and simple(More)
We present a parallel implementation of a constraint-based local search algorithm and investigate its performance results on hardware with several hundreds of processors. We choose as basic constraint solving algorithm for these experiments the ”adaptive search” method, an efficient sequential local search method for Constraint Satisfaction Problems. The(More)
In this article we present the University of Evora’s Integrated Information System (SIIUE), which is meant to model most of the information necessary for the management and day-to-day operation of an institution such as a public University. SIIUE is centered around a logicbased representation of all intervenients and processes, which is used to generate the(More)
We investigated the use of the Cell Broadband Engine (Cell/BE) for constraint-based local search and combinatorial optimization applications. We presented a parallel version of a constraint-based local search algorithm that was chosen because it fits very well the Cell/BE architecture because it requires neither shared memory nor communication among(More)
There has been an increased interest in temporal reasoning from areas such as database systems and AI. In this paper we propose a temporal reasoning framework that bridges the paradigms of Constraint Logic Programming (CLP) and Contextual Logic Programming (CxLP). CLP is used to build a rather simple, yet powerful temporal algebra with points, intervals,(More)
We describe a system in which Contextual Logic Programming is used as a mediator for knowledge modeled by ontologies. Our system provides the components required to behave as a SPARQL query engine and, as a result of its Logic Programming heritage, it may also recursively interrogate other ontologies or data repositories, providing a semantic integration of(More)