Personal page of Mariem Mahfoudh describing her research and publications.

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Algebraic Graph Transformations for Formalizing Ontology Changes and Evolving Ontologies

Article in International Journal
M. Mahfoudh, G. Forestier, L. Thiry, and M. Hassenforder
Knowledge-Based Systems (Impact Factor: 3.058 ), volume 73, Elsevier, pages 212–226, 2015
Companion web page (source code of the implementation)

An ontology represents a consensus on the representation of the concepts and axioms of a given domain. This consensus is often reached through an iterative process, each iteration consisting in modifying the current version of the consensus. Furthermore, frequent and continuous changes are also occurring when the represented domain evolves or when new requirements have to be considered. Consequently, ontologies have to be adaptable to handle evolution, revision and refinement. However, this process is highly challenging as it is often difficult to understand all affected ontology parts when changes are performed. Thus, inconsistencies can occur in the ontology as the changes can introduce contradictory axioms. To address this issue, this paper presents a formal approach for evolving ontologies using Typed Graph Grammars. This method relies on the algebraic approach Simple PushOut (SPO) of graph transformations. It formalizes the ontology changes and proposes an a priori approach of inconsistencies resolution. The modified ontology does not need an explicit checking as an incorrect ontology version cannot actually be generated. To validate our proposal, an implementation is presented using the Attributed Graph Grammar (AGG) toolbox.

 

A Functional Inference System for the Web

Article in International Journal
L. Thiry, M. Mahfoudh and M. Hassenforder
International Journal of Web Applications, volume 6, pages 1-13, 2014

This paper explains how functional programming (FP) helps to integrate both theoretical and technological models by using generic datatypes and higher-order functions. As an application, the paper considers the domains of knowledge modeling and web technologies. More precisely, it explains how FP can be used to infer and to generate web pages from a graph based datamodel, or to embed a query language (helpful to search for a precise information). It then shows how the concepts lead to a generic platform dedicated to knowledge sharing and searching with an application to the CCAlps European project.

Mapping Natural Language to Description Logic

Communication to International Conference
B. Gyawali, A. Shimorina, C. Gardent, S. Cruz-Lara, and M. Mahfoudh
Extended Semantic Web Conference, 2017

A benchmark for ontologies merging assessment

Communication to International Conference
M. Mahfoudh, G. Forestier, and M. Hassenforder
International Conference on Knowledge Science, Engineering and Management, pages 1-12, Passau, Germany, 2016
Companion web page (source code of the implementation)

In the last years, ontology modeling became popular and thousands of ontologies covering multiple fields of application are now available.
However, as multiple ontologies might be available on the same or related domain, there is an urgent need for tools to compare, match, merge and assess ontologies.
Ontology matching, which consists in aligning ontology, has been widely studied and benchmarks exist to evaluate the different matching methods.
However, somewhat surprisingly, there are no significant benchmarks for merging ontologies, proving input ontologies and the resulting merged ontology.
To fill this gap, we propose a benchmark for ontologies merging, which contains different ontologies types, for instance: taxonomies, lightweight ontologies, heavyweight ontologies and multilingual ontologies.
We also show how the GROM tool (Graph Rewriting for Ontology Merging) can address the merging process and we evaluate it based on coverage, redundancy and coherence metrics.
We performed experiments and show that the tool obtained good results in terms of redundancy and coherence.

Algebraic Graph Transformations for Merging Ontologies

Communication to International Conference
M. Mahfoudh, L. Thiry, G. Forestier, and M. Hassenforder.
International Conference on Model & Data Engineering, pages 154-168, Larnaca, Cyprus, 2014
Companion web page (source code of the implementation)

The conception of an ontology is a complex task influenced by numerous factors like the point of view of the authors or the level of details. Consequently, several ontologies have been developed to model identical or related domains leading to partially overlapping representations. This divergence of conceptualization requires the study of ontologies merging in order to create a common repository of knowledge and integrate various sources of information. In this paper, we propose a formal approach for merging ontologies using typed graph grammars. This method relies on the algebraic approach to graph transformations, SPO (Simple PushOut) which allows a formal representation and ensures the consistence of the results. Furthermore, a new ontologies merging algorithm called GROM (Graph Rewriting for Ontology Merging) is presented.

Consistent ontologies evolution using graph grammars

Communication to International Conference
M. Mahfoudh, G. Forestier, L. Thiry, and M. Hassenforder
International Conference on Knowledge Science, Engineering and Management, volume 8041 of LNCS, pages 64-75, Dalian, China, 2013
Companion web page (source code of the implementation)

Ontologies are often used for the meta-modelling of dynamic domains, therefore it is essential to represent and manage their changes and to adapt them to new requirements. Due to changes, an ontology may become invalid and non-interpretable. This paper proposes the use of the graph grammars to formalize and manage ontologies evolution. The objective is to present an a priori approach of inconsistencies resolutions to adapt the ontologies and preserve their consistency. A framework composed of different graph rewriting rules is proposed and presented using the AGG (Algebraic Graph Grammar) tool. An implementation allowing to transform back and forth an OWL ontology to an AGG graph illustrates the approach. As application, the article considers EventCCAlps ontology developed in the frame of the European project CCAlps.

Comment fusionner des ontologies avec la réécriture de graphes ?

Article in National Journal
M. Mahfoudh, G. Forestier, L. Thiry, and M. Hassenforder
Techniques et Sciences Informatiques, volume 35 of Hermes, pages 31-53,2016

Au cours de ces dernières années, les ontologies se sont imposées comme un outil incontournable de représentation des connaissances. Cette popularité a conduit au développement d’ontologies similaires ou partiellement redondantes. Cette multiplication de ressources disponibles a mené aux études traitant de leur réutilisation et/ou leur fusion. Dans ce contexte, nous proposons une nouvelle approche de fusion d’ontologies basée sur les règles de réécriture de graphes. A l’aide du domaine des grammaires de graphes typés, nous avons défini un nouveau formalisme capable de représenter des ontologies et de produire le résultat de leur fusion. Pour valider notre proposition, l’approche a été implémentée et testée sur une dizaine d’ontologies dans différents domaines d’application.

Approche de couplage de BD et d’ontologie pour l'aide à la décision sémantique : contribution pour la satisfaction des requêtes SQL et SPARQL

Article in National Journal
M. Mahfoudh and W. Jaziri
Techniques et Sciences Informatiques, volume 32 of Hermes, pages 863-889, 2013

La modélisation des systèmes d’information et l’interrogation de leurs données présentent de plus en plus un défi primordial qui ne cesse de s’imposer. Les solutions proposées dans la littérature étaient principalement organisées autour des bases de données (BD), des entrepôts de données et plus récemment, des ontologies. Cette multitude de formalismes a entraîné la nécessité d’étudier le couplage entre les différents supports de stockage et d’interrogation de l’information. Cet article s’intéresse au couplage entre BD et ontologie recouvrant le même domaine d’étude, pour la satisfaction des requêtes utilisateurs. L’approche proposée se base sur un ensemble de règles définies et dédiées pour la recherche de l’information pertinente permettant de satisfaire les requêtes SQL et SPARQL. Un outil de couplage est également développé pour implémenter et valider nos propositions.

The ModelWriter project

Communication to International Workshop
C. Gardent, A. Luna and M. Mahfoudh
International Workshop on Natural Language Generation from the Semantic Web, Nancy, France, 2015

Une nouvelle formalisation des changements ontologiques composés et complexes

Communication to National Conference
M. Mahfoudh, L. Thiry, G. Forestier, and M. Hassenforder
Extraction et Gestion des Connaissances, RNTI-E-28, pages 263-274, Luxembourg, Luxembourg, 2015

Adaptation consistante d'ontologies à l'aide des grammaires de graphe

Communication to National Conference
M. Mahfoudh, L. Thiry, G. Forestier, and M. Hassenforder
Conférence d'Ingénierie des Connaissances, IC 2013, Lille, France, 2013

Comment fusionner des ontologies avec la réécriture de graphes ?

Communication to National Conference
M. Mahfoudh, G. Forestier, L. Thiry, and M. Hassenforder
Journées Francophones sur les Ontologies, pages 89-100, Hammamet, Tunisie, 2014

Approche formelle de fusion d'ontologies à l'aide des grammaires de graphes typés

Communication to National Conference
M. Mahfoudh, G. Forestier, L. Thiry, and M. Hassenforder
Extraction et Gestion des Connaissances, volume of RNTI-E-26, pages 565-568, Rennes, France, 2014

Approche de couplage de BD et d'ontologie pour la satisfaction de requêtes SQL et SPARQL

Communication to National Conference
M. Mahfoudh and W. Jaziri
Journée Francophone sur les ontologies, pages 117-132, JFO 2011, Montréal, Canada, 2011
The paper received the best paper award

D.2.2.1 Overview and comparison of existing deep semantic parsers

Technical report
C. Gardent and M.Mahfoudh
CNRS-LORIA, ModelWriter Project, 34 pages, 2016

D.2.4.1 Specification of the Knowledge Representation Language output by the Parser and input to the Generator

Technical report
M.Mahfoudh and C.Gardent
CNRS-LORIA, ModelWriter Project, 11 pages, 2016