Ontologías para sistemas mediadores

Abstract

In Computer Sciences, mediators systems are defined as «computer software that exploit the knowledge related to a set of data in order to create information for users' applications» (Wiederhold, 1992).

The objective of the mediators is to simplify, to abstract, to reduce, to integrate and to combine data from different sources in order to give better answers to user's queries. A mediator system is specific to an application domain. This is described by a global schema or domain ontology. The role of ontology is central to the schema because it is the support for the expression of users' queries. Also, it is through this schema that the different sources of data are interconnected.

The automated construction of mediators systems can be initially approached by automating the construction of a fundamental part ofthese systems, as ontology is. Some methods and techniques to construct, as automatically as possible, a domain ontology for a mediator system, were the topic of investigation carried out foe a PhD thesis at LRI (Laboratoire de Recherche en Informatique) in the Paris Sud XI University (Orsay-France).

The proposed solution is made up ofthree stages: The first one, the extraction of the elements that make up the ontology, starting with a set of DTDs (Document Type Definition). Second, the organisation ofthese elements and the last stage is their representation. The  techniques that are suggested have been implemented in a system named OntoMedia. The objective of this article is to show the first results of such research. Due to space limitations, the first and the second stage are presented. The third stage will appear in a publication to follow.

Considering that ontologies have a great deal of applications at the moment, a lot of subjects are left for future research. As a consequence, we are developing a sub-line, ascribed to the team that is doing research in integration of solutions with informatics and communication technologies - a research group at ITM. The important aspects that justify keeping on research in this field are mentioned in the final part of this article.