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Andrei Popescu-Belis

Multi-agent modeling of linguistic interaction:
application to the problem of linguistic
reference and to its evaluation

Ph.D. in computer science
Paris-XI University, Orsay


Linguistic interaction is studied here within a multi-agent framework that we call "simulated pragmatics". Adapting G. M. Edelman's neural darwinism to build an adaptive agent is a first step towards naturalistic bases of language for an agent. Our simulation of the emergence of language conventions in an agent population then demonstrates the advantage of using a lexicalized tree adjoining grammar.

These achievements do not investigate, however, the essential link between the communication code and the entities it might denote, mainly the problem of linguistic reference. After presenting the existent theories, models and systems, we identify eleven referential cases and their expression in French, from a functionalist point of view. We propose a model for the referring capacity of an agent, which links the referring cases to perceptual states. In order to study reference on real texts, a pragmatics-inspired model is also proposed, relying on the agents' internal representations. This model is adapted to build a reference solver; the related tools and the results are given further on.

These results are based on an original frame for natural language processing systems evaluation, together with coherence criteria for quality measures. Several measures, some existing and some original, are analyzed; we define "referring information" for a measure adapted to agent communication. These measures allow us to compare our solver with other approaches, to optimize its parameters, and to support some of the previous results on the expression of referential cases.

Download the dissertation (in French)
(gzipped Postscript, from MS-Word97 files)
Page de titre - Remerciements - Sommaire - Introduction - Chapitre I Approche symbolique et nouvelles voies en IA et TAL - Chapitre II Réalités et simulations de la communication langagière
301 Ko
Chapitre III Principes de modélisation : la « pragmatique simulée » - Chapitre IV Deux réalisations : études d'un agent et d'une société
321 Ko
Chapitre V La référence : théorie, modèles, systèmes - Chapitre VI Du fonctionnement de la référence à la capacité référentielle d'un agent 
384 Ko
Chapitre VII Résolution de la référence : un modèle représentationnel et son implémentation
215 Ko
Chapitre VIII Cadre théorique et conditions de cohérence des mesures d'évaluation - Chapitre IX Critiques et propositions pour évaluer le traitement de la référence 
278 Ko
Conclusion - Annexes - Références - Table des matières détaillée
690 Ko

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June 21, 2000