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PhD thesis defense: Nizar Ghoula

Title: An Ontology Based Repository for Combining Heterogeneous Knowledge Resources

Date: Friday December 12th 2014 at 3pm

 

Place: Battelle bâtiment A - Auditoire rez-de-chaussée

Jury:

  • President: Giovanna Di Marzo Serugendo, Professor, University of Geneva
  • Thesis director: Gilles Falquet. Professor, University of Geneva
  • External Jury: Dr. Khaled Khelif, Research Engineer, Airbus Defence and Space, France
  • Jury: Dr. Claudine Métral, MER, University of Geneva
  • External Jury: Dr. Jacques Guyot, Founder of Open Languages tools foundation.

 

Abstract :

Many tasks related to documents, such as indexing, retrieving, annotation, or translation are based on linguistic, terminological and ontological knowledge existing in resources of different types such as terminologies, glossaries, ontologies, multilingual dictionaries or text corpora. These resources are represented using various formalisms and languages such as predicate logic, description logic, semantic networks and conceptual graphs, etc. As part of an application that requires the use of external resources, a designer is often required to perform painstaking research and pre-treatment in order to collect and build adequate resources to his application needs. This requires the representation of heterogeneous knowledge resources using specific formalisms, extracting the required knowledge and design effective large-scale storage structures offering operators for resources management. Resources repositories have been created to help in this task by collecting different resources in different formalisms. They generally offer a more effective indexing of these resources than general search engines and generate alignments and annotations to ensure interoperability between resources. However, these repositories treat a single category of resources and do not provide operations for generating new resources.
 
The aim of this research work is to conceive and design a repository for combining heterogeneous knowledge resources. Such a repository is a collection of heterogeneous resources represented by multiple formalisms and offers tools and operators to derive new resources by combining the existing ones. This derivation may involve operations such as selecting a part of a resource, composing it with another one, translating it to another language or representing it in a different formalism. To meet these needs in terms of knowledge engineering and representation, our first contribution is an ontology for representing heterogeneous resources and knowledge combination operators. The representation of these operators supports multiple implementations. Our second contribution is an approach based on the principles of semantic web, metadata and ontologies to facilitate the representation, storage and alignment of heterogeneous and multilingual resources. Our third contribution is the development of an ontology-based repository for combining alignment resources. This repository is supported by a set of knowledge engineering operators that composes and aggregate existing alignments generated by different tools. We show in particular that alignment composition can effectively improve the results of ontology matchers.
 

 

December 4, 2014
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