Brigitte Safar, Hassen Kefi, Chantal Reynaud, OntoRefiner, a user query refinement interface usable for Semantic Web Portals, Application of Semantic Web Technologies to Web Communities Workshop, 16th European Conference on Artificial Intelligence, August 22-27, 2004, Valencia, Spain.

We present a user interface, the OntoRefiner system, for helping the user to navigate numerous retrieved documents after a search querying a semantic portal which integrates a very important number of documents. Retrieved answers are filtered and the user could be provided only with the answers which are, according to im, the most relevant. The refinement process is based on two technologies, dynamic clustering close to Galois lattice structure combined to the use of a domain ontology. The Galois lattice structure provides a sound basis for the query refinement process. However, its construction as a whole is a very costly process. So, we propose an approach based on the use of a domain ontology, avoiding the cosntruction of the whole Galois lattice. In the paper, we present the algorithm and experimental results.

Chantal Reynaud, Building Scalable Mediator Systems, Topical Day in Semantic Integration of Heterogeneous Data, IFIP World Computer Congress, Toulouse, August 23, 2004.

This paper deals with Picsel mediator systems which integrate services. We propose a scalable approach which exploits standardized specifications provided by normalization organisms. The paper focuses on the use of such specifications to automate the construction of the mediator. An illustration in the tourism domain with OTA specifications is given.

Marie-Christine Rousset, Chantal Reynaud, Knowledge representation for Information integration, Information Systems International Journal, Special issue: Web-Universal Integration, volume 29, Number 1, P. 3-22.

An information integration agent provides a uniform query interface to a collection of distributed and heterogeneous information sources, giving users or other agents the illusion that they interrogate a centralized and homogeneous information system. In this paper, we focus on the use of knowledge representation techniques for building mediators for information integration. A mediator is based on the specification of a single mediated schema describing a domain of interest, and on a set of source descriptions expressing how the content of each source available to the system is related to the domain of interest. These source descriptions, also called mappings because they model the correspondence between the mediated schema and the schemas of the data sources, play a central role in the query answering process. We present two recent information integration agents, namely PICSEL and Xyleme, which are illustrative of two radically different choices concerning the expressivity of the mediated schema.

Chantal Reynaud, Brigitte Safar, Hélène Gagliardi, Une expérience de représentation d'une ontologie dans le médiateur PICSEL, Editions Eyrolles, à paraître.

Building an information server, specific to a given domain, over distributed and heterogeneous information sources, is based on knowledge describing the server domain, called domain ontology. We address the issue of representing such ontologies in the framework of the PICSEL research project. Two steps are described. The first one is directed by the representation formalism and the functionalities of the information server. The second one aims at refining and optimizing knowledge obtained in step one. It is guided by the way functionalities of the server is implemented. The examples in the paper are coming from the tourism products domain.

Chantal Reynaud,Gloria Giraldo, An Application of the Mediator Approach to Services over the Web, Special track "Data Integration in Engineering", Proceedings of CE'2003, p. 209-216, 26-30 July, Portugal.

This document is about mediation systems integrating services over the web. First we give an overview of the mediator approach. In section 3 we focus on integration of services over the web. We explain which problems arise and we give principles to make the mediator approach applicable in the context. The first principle is a solution to semantic heterogeneity. It exploits results in standardization relative to business transactions. The second principle concerns the scalability of the mediator approcah. It emphasizes two points: de-coupling of the various components and strong mediation. In the last section, we present an architecture of a mediation system integrating services, designed in the setting of the PICSEL 2 project. We illustrate with an application of e-commerce in the tourism domain.

Chantal Reynaud,Gloria Giraldo, Mediation de services sur le Web, Journées Francophones de la Toile, Tours, 30 Juin - 2 Juillet.

This document is about mediation systems integrating services on the Web to make them usable to final users. As services on the Web are numerous and heterogeneous, as they must sometimes be combined to satisfy final users requirements, intefaces giving the illusion of a convivial, unique, centralized and homogeneous access are necessary. In this paper, we propose to use a mediator approach to design such an interface. First, we give an overview of the mediator approach. Then section 3 is about problems specific to mediation systems integrating services on the web. We explain which problems areise and we give principles to make the mediator approach applicable in this context. The first principle is a solution to semantic heterogeneity. It exploits results in standardization relative to business trnasactions. The second principle concerns the scalability of the mediator approach. It emphasizes two points: decoupling of the various components and strong mediation. In the last section, we present an architecture of a mediation system integrating services, designed in the setting of the PICSEL 2 project. We illustrate with an application of e-commerce in the tourism domain.

Claude Delobel, Chantal Reynaud, Marie-Christine Rousset, Jean-Pierre Sirot, Dan Vodislav, Semantic Integration in Xyleme: a Uniform Tree-Based Approach, Data and Knowledge Engineering Review.

Xyleme is a huge warehouse integrating XML data of the Web. Xyleme considers a simple data model with data trees and tree types for describing the data sources, and a simple query language based on tree queries with boolean conditions. The main components of the data model are a mediated schema modeled by an abstract tree type, as a view of a set of tree types associated with actual data trees, called concrete tree types, and a mapping expressing the connection between the mediated schema and the concrete tree types. The first contribution of this paper is formal: we provide a declarative model-theoretic semantics for Xyleme tree queries, a way of checking tree query containment, and a characterization of tree queries as a composition of branch queries. The other contributions are algorithmic and handle the potentially huge size of the mapping relation which is a crucial issue for semantic integration and query evaluation in Xyleme. First, we propose a method for pre-evaluating queries at compile time by storing some specific meta-information about the mapping into map translation tables. These map translation tables summarize the set of all the branch queries that can be generated from the mediated schema and the set of all the mappings. Then, we propose different operators and strategies for relaxing queries which, having an empty map translation table, will have no answer if they are evaluated against the data. Finally, we present a method for semi-automatically generating the mapping relation.

Marie-Christine Rousset, Christine Froidevaux, Hélène Gagliardi, François Goasdoué, Chantal Reynaud, Brigitte Safar, Construction de médiateurs pour intégrer des sources d'information multiples et hétérogènes : le projet PICSEL, Revue I3.

The aim of this paper is the description of the PICSEL project, a declarative framework to build mediators. The approach which has been chosen in PICSEL is to define an information server as a knowledge-based mediator in which CARIN is used as the core logical formalism to represent both the domain of application and the contents of information sources relevant to that domain. CARIN combines the expressive power of rules and the ALN description logics. PICSEL is equiped with a cooperative module to refine queries posed to a mediator which gets no answer.

Marie-Christine Rousset, Chantal Reynaud, PICSEL and XYLEME: two illustrative information integration agents, Book Chapter in Intelligent Information Agents Research and Development in Europe: An AgentLink Perspective editors : mathias Klusch, Sonia Bergamaschi, Paolo Petta, Pete Edwards; Publisher : Springer verlag, LNCS State of the Art Surveys.

An information intégration agent provides a uniform query interface to a collection of distributed and heterogeneous sources, giving the users or other agents the illusion that they interrogate a centralized and homogeneous infromation system. In this chapter we focus on integration information agents that follow a mediator approach. A mediator is based on the specification of a single mediated schema describing a domain of interest, and on a set of source descriptions expressing how the content of each source available to the system is related to the domain of interest. These source descriptions, also called mappings becuse they model the correspondence between the mediated schema and the schemas of the data sources, play a central role in the query answering process. We present two recent information integration agents, namely PICSEL and XYLEME, which are illustrative of two radically different choices concerning the expressivity of the mediated schema.

Chantal Reynaud, Brigitte Safar, Representation of Ontologies for Information Integration, EKAW'02, International Conference on Knowledge Engineering and Knowledge Management. 1-4 October 2002, Siguenza, Spain.

An information integration system provides a uniform query interface to a collection of autonomous and distributed sources, connected to each other thanks to a global mediated schema, called domain ontology. The problem addressed in the paper is how to represent such an ontology into CARIN-ALN, a formalism combining classes and rules. We focus on the choices for representing classes, properties and constraints using the characteristics of the formalism. We also propose a method in two steps for representing a domain ontology in the framework of a mediator. The first step is directed by the formalism and the functionalities of the mediator. The second step is an optimization phase guided by the way functionalities of the mediator are implemented.

Marie-Christine Rousset, Christine Froidevaux, Hélène Gagliardi, François Goasdoué, Chantal Reynaud, Brigitte Safar, Construction de médiateurs pour intégrer des sources d'information multiples et hétérogènes : le projet PICSEL, Revue I3.

The aim of this paper is the description of the PICSEL project, a declarative framework to build mediators. The approach which has been chosen in PICSEL is to define an information server as a knowledge-based mediator in which CARIN is used as the core logical formalism to represent both the domain of application and the contents of information sources relevant to that domain. CARIN combines the expressive power of rules and the ALN description logics. PICSEL is equiped with a cooperative module to refine queries posed to a mediator which gets no answer.

Chantal Reynaud, Brigitte Safar, Aide à la formulation de requetes dans un médiateur, 13èmes congrès francophone AFRIF-AFIA de Reconnaissance des Formes et Intelligence Artificielle, 8-10 janvier 2002, Angers.

Information integration over existing sources that are distributed and possibly heterogeneous is complex. Mediator systems have in common the use of a domain model, also called ontology. The paper addresses the benefits coming from using such an ontology in order to help users to pose queries and present the inference mechanisms which have been developed in the context of the PICSEL project. We illustrate these works with examples coming the tourism domain.

Gloria Giraldo, Chantal Reynaud, Construction semi-automatique d'ontologies à partir de DTDs relatives à un meme domaine, 13èmes journées francophones d'Ingénierie des Connaissances, Rouen, 28-30 Mai 2002.

A mediator system is composed of a global schema, or domain ontology, whose role is twofold. First, it conects all the autonomous and distributed sources to each other. Second, it allows users to pose queries in terms of the mediated schema rather than directly in terms of the sources schemas. In this paper, we focus on the automation of the construction of an ontology in the context of a domain-specific mediator querying XML documents. The ontology that we want to build is a schema based on classes. The approach is based on the DTDs associated to the XML documents. The paper describes it and presents results coming from the first experiments.

2001

Chantal Reynaud, Jean-Pierre Sirot, Dan Vodislav, Semantic Integration of XML Heterogeneous Data Sources, International DataBase Engineering & Applications Symposium: IDEAS'01, 18-20 Juillet 2001, Grenoble.

With the current explosion of data, retrieving and integrating information from various sources is a critical problem. The designer has to specify a mediated schema providing a homogeneous view on the sources. In this paper, we report on an initial work toward automatically generating mappings between elements in the sources and in the mediated schema. Information sources we are interested in are XML documents in respect with a Document Type Definition (DTD). We describe the Xyleme project, which is the context of this study. We present our approach implemented in the SAMAG system to automatically finf mappings on the basis of semantic and structural criteria. Finally, we report the first results of an experiment where SAMAG has been applied to XML documents in the cultural domain.

Chantal Reynaud, Brigitte Safar, Hélène Gagliardi, La représentation de l'ontologie du domaine dans le médiateur PICSEL , 12èmes Journées Francophones d'Ingénierie des Connaissances, IC'01, Grenoble, 25-27 Juin 2001.

An information integration system provides a uniform query interface to a collection of autonomous and distributed sources, connected to each other thanks to a global mediated schema, called domain ontology. The problem addressed in the paper is how to represent such an ontology into CARIN-ALN, a formalism combining classes and rules. We focus on the choices for representing classes, properties and constraints using the characteristics of the formalism. We also propose a method in two steps for representing a domain ontology in the framework of a mediator. The first step is directed by the formalism and the functionalities of the mediator. The second step is an optimization phase guided by the way functionalities of the mediator are implemented.

Hélène Gagliardi, Chantal Reynaud, Brigitte Safar, La conception d'une interface de serveur d'information basée sur une terminologie CARIN , 12èmes Journées Francophones d'Ingénierie des Connaissances, IC'01, Grenoble, 25-27 Juin 2001. Présentation sous forme de poster.

The paper describes an intelligent interface for querying the PICSEL mediator. Benefits coming from using an ontology in mediator systems are explained and inference mechanisms based on the logical formalism, CARIN, used to represent the ontology are detailed.

Jean Charlet, Chantal Reynaud and Régine Teulier, Ingénierie des connaissances pour les systèmes d'information, Ingénierie des Systèmes d'Information, Hermès, Traité IC2, Ch. 10, p. 277-316.

This paper deals with epistemological problems in knowledge engineering. It describes the key points of the research in knowledge engineering, particularly modeling methods and reusability. It gives also an organisational point of view on the domain. Finally the last section confronts knowledge engineering with information system engineering.

2000

Chantal Reynaud and Françoise Tort, Diriger la réutilisation de composants à l'aide d'ontologies J. Charlet, M. Zacklad, D. Bourigault, Eds, Ingénierie des connaissances, évolutions récentes et nouveaux défis, Eyrolles.

This paper deals with the automated construction of problem solving methods from formally specified domain ontologies. Only reused aspects are addressed. The aim is to show that the approach is not incompatible with reuse though it is opposite to approaches based on generic methods. We propose to design a model of reasoning by configuring elementary generic predefined components. An organisation of libraries of such components is described.

1999

François Goasdoué and Chantal Reynaud, Modeling Information Sources for Information Integration, Dieter Fensel, Rudi Studer, Eds, 11th European Workshop on Knowledge Acquisition, Modeling and Management, EKAW'99, p. 121-138, Lecture Notes in AI 1621, Springer-Verlag, agstuhl Castle, Germany, 26-29 May.

A critical problem in building an information mediator is to design knowledge bases describing the contents of information sources. Concepts which capture abstractions in information sources and which are usable to describe their content must be identified. This paper addresses this knowledge acquisition problem in the context of the PICSEL project, when information sources are relational databases.

1998

Chantal Reynaud, Nathalie Aussenac-Gilles and Françoise Tort, A support to domain knowledge modelling, Information Modelling and Knowledge Bases IX, P.J. Charrel, Jaakkola H., Kangasalo H., Kawaguchi E. (Eds), IOS Press, Amsterdam - Frontiers in Artificial Intelligence and Applications, p. 35-50. Toulouse, 27-30 May, 1997.

In this paper, we first show that the extended E/R Model offers constructs that fulfil the requirements in domain knowledge modeling. Then, we present how it helps to identify concepts, to structure the domain model and to elicit additional domain knowledge. In a second part of the paper, we focus on a case study in the context of an operational project. Through this cas, we explain how the language helps in analysing the information acquired during interviews, we report the consequences on the model and in a last section, we list four structuring criteria which guided us in the ontology design.

Chantal Reynaud and Françoise Tort, Spécification de méthodes de composants réutilisés, In Proceedings of IC'98, Pont-à-Mousson, France, 13-15 may.

In this paper, we show that the approach which is adopted in ASTREE is also a contribution to works in the reuse field.

1997

Chantal Reynaud and Françoise Tort, Using Explicit Ontologies to Create Problem-Solving Methods In International Journal of Human-Computer Studies (IJHCS), 46, 339-364.

The article describes a tool called ASTREE, based on an ontology-driven approah. ASTREE has been designed to automate the construction of an application-specific model of problem-solving behaviour in cases where skeletal models connot be reused. In ASTREE, the construction of a problem-solving model is an identification of methods capable of achieving user-specified tasks. The identification process is based on matching elements specified in the task to be achieved and elements in a set of domain knowledge delivered by an expert. The domain knowledge is called the expertise ontology. It is argued in this paper that a well-defined expertise ontology provides strong constraints for the knowledge engineering process, and in particular, for the creation of a model of problem-solving behaviour. This analysis suggests some developments to better exploit the relationship between reasonng and domain knowledge.

Chantal Reynaud, Nathalie Aussenac-Gilles, Pierre Tchounikine, Francky Trichet, The Notion of Role in Conceptual Modeling, Enric Plaza, Richard Benjamins, Eds., Knowledge Acquisition Modeling and Management, EKAW'97, p. 221-236, Lecture Notes in AI 1319, Springer-Verlag, Sant Feliu de Guixols, Catalonia, Espagne, October 15-18.

In this article we analyse the notion of knowledge role. First of all, we present how the relationship between problem solving methods and domain models is tackled in different approaches. We concentrate on how they cope with this issue in the knowledge engineering process. Secondly, we introduce several properties which can be used to analyse, characterise and define the notion of role. We evaluate and compare the works exposed previously following three dimensions.This analysis suggests some developments to better exploit the relationship between reasoning and domain knowledge.

1996

Chantal Reynaud, Françoise Tort, Use of expertise ontologies in the knowledge engineering process Proceedings of IEEE International Conference on Tools with Artificial Intelligence (ICTAI'96), Toulouse, France, 16-19 nov, p. 106-109.

In this article, we describe an approach, supported by a tool, called ASTREE, designed to automate the construction of a problem-solving behaviour in cases where skeletal models cannot be reused. Such a construction is an identification of methods capable of achieving user-specified tasks. The article focuses on the main techniques that ASTREE uses in the identification process.

Jean Charlet, Chantal Reynaud, Jean-Paul Krivine, Causal model-based knowledge acquisition tools : discussion of experiments Int. Journal of Human-Computer Studies (IJHCS), 44, p. 629-652.

The aim of this paper is to study causal knowledge and demonstrate how it can be used to support the knowledge acquisition process. The discussion is based on three experiments we have been involved in. First, we identify two classes of Causal Model-Based Knowledge Acquisition Tools (CMBKATs) : bottom-up designed causal models and top-down designed causal models. We then go on to discuss the properties of each type of tool and how they contribute to the whole knowledge acquisition process.

Nathalie Aussenac-Gilles, Philippe Laublet, Chantal Reynaud, L'acquisition des connaissances, une composante à part entière de l'informatique du futur AUSSENAC-GILLES N., LAUBLET P., REYNAUD C., Eds, Acquisition et ingénierie de la connaissance - Tendances actuelles, Cepadues, p. 3-25.

In this paper, we show that works in knowledge engineering can be very fruitful for domains different from artificial intelligence and then that answers proposed in knowledge engineering can be reused outside the field of knowledge based systems. Furthermore, the evolution of the knowledge acquisition domain is described, the key points of the evolution are presented followed by the main research themes in France in knowledge acquisition.

Françoise Tort and Chantal Reynaud, Exploiter des connaissances causales pour modéliser; une expertise, Nathalie Aussenac-Gilles, Philippe Laublet, Chantal Reynaud, Eds, Acquisition et ingénierie de la connaissance - Tendances actuelles, Cepadues, p. 207-224.

The aim of this paper is to show how an approach based on techniques for knowledge represented in an operational language have been adapted for knowledge modeling. These techniques are applied on causal models acquired independently from reasoning.