Sébastien Ferré  -  professional page

Sébastien Ferré
: Irisa/Ifsic
Université de Rennes 1
Campus de Beaulieu
35042 Rennes cedex

: +33 2 99 84 75 70

: +33 2 99 94 71 71

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Welcome to my web page.
I am an assistant professor in computer science at the University of Rennes 1,
and I am a member of the research team LIS in the Irisa laboratory.

Curriculum Vitae

Subject of my PhD

Title: Logical Information Systems: a logico-contextual paradigm for querying, navigating, and learning.

Keywords : information systems, file systems, databases (relational, object and deductive), concept analysis, querying, navigation, knowledge representation, description logics, views, software engineering.

Subject : Many computer environments are based on rigid navigational structures: file systems, programming environments, hypertext, Web, etc. This kind of organisation is not well adapted to the diversity of the users and their objectives, and to their evolution. More recent proposals define structures better adapted to the diversity of points of view, but they are often either overspecialized (e.g., in software engineering), or ad-hoc (e.g., access to files by their content).

On the contrary, we want an information structure that

We propose to study navigational structures based on properties of terminal objects. They have to be navigational to make it possible to steadily explore a set of objects, but the links supporting the navigation will not be induced from the representation of objects. The contents of terminal objects will contribute to the elaboration of intrinsic properties of these objects, but some extrinsic properties will also be elaborated, especially at the creation of these objects.
This project is composed of a fundamental aspect, which has to offer a formal modelisation of these structures, and an applied aspect, whose aim is to realise a prototype of file system so as to validate chosen options. The first formalisms to consider are on one hand Concept Analysis for modelling navigational structures, and on the other part description logics for representing properties of the objetcs. Preferred applications will be software engineering and information servers for a large public (e.g., catalogues, guides).

Summary: Both main paradigms of information retrieval (IR), which are navigation and querying, are often disconnected in existing systems. Hierarchical systems (e.g., file systems, Web) have a rigid navigation structure that is not appropriate to all users and all uses; what is compensated by searching tools (e.g., command "find", search engines). These tools, based on querying, are more flexible but are difficult to use for non-expert users and make it hard to control the number of answers. Therefore, it looks like necessary to tightly combine navigation and querying in IR.

In order to achieve this combination, we use as a fundation Concept Analysis (CA). Given a description of the objects of a system, it enables to automatically build a navigation structure called "concept lattice", where concepts plays as both directories and queries. As object descriptions are limited to sets of attributes in CA, we first generalized CA by replacing them by formulas of an almost arbitrary logic. We feel this genericity is important to handle various applications. Logical Information Systems (LIS) are therefore defined by the combination navigation/querying, the use of logic (for descriptions, queries, navigation links), and logical genericity.

On this basis, we developed several mechanisms intended to facilitate expression and discovery of knowledge. Some knowledge about an application domain can be expressed through a terminology. A human-machine dialog, based on the concept lattice, allows the user to retrieve objects (navigation), and discover patterns among objects (knowledge discovery). A learning mechanism helps the user to classify new objects. To end, a prototype has been developed, allowing experimentation of these mechanisms through concrete applications (e.g., bibliographical references, emails, receipts). It is generic in the sense that it does not depend on the logic used in each application. To help the building of these logics, we realized a toolbox of logical components, which can be freely composed.

Teaching Activities


Last update: 06/03/2007.