Etude du changement en argumentation : de la théorie à la pratique

L'argumentation, au sens de l'intelligence artificielle, est un formalisme permettant de raisonner à partir d'informations incomplètes et/ou contradictoires ainsi que de modéliser un échange d'arguments entre plusieurs agents. Un système d'argumentation consiste généralement en un ensemble d'arguments interagissant les uns avec les autres, et duquel il est possible d'extraire un ou plusieurs points de vue cohérents. Dans cette thèse, nous nous plaçons dans le cadre de l'argumentation abstraite dans lequel les arguments sont manipulés en tant qu'entités abstraites dont le sens nous est inconnu et dans lequel les interactions représentent des conflits. Ceci nous permet de nous concentrer sur le point particulier de la dynamique dans les systèmes d'argumentation abstraits, c'est-à-dire les changements pouvant impacter ces systèmes, notamment dans le cadre d'un dialogue. Nous commençons par justifier l'intérêt d'un tel cadre formel puis nous nous intéressons au comment et au pourquoi du changement en argumentation abstraite. Le comment est approché en établissant une liste des modifications que peut subir un système d'argumentation et en étudiant sous quelles conditions elles peuvent survenir. Le pourquoi est abordé par l'introduction de la notion de but motivant un changement et le choix du meilleur changement à faire pour satisfaire un but en prenant en considération des contraintes portant sur l'agent à convaincre. Enfin, nous concrétisons notre étude en proposant un outil logiciel implémentant les notions introduites et nous étudions ses performances.Argumentation, in the field of artificial intelligence, is a formalism allowing to reason with incomplete and/or contradictory information as well as to model an exchange of arguments between several agents. An argumentation system usually consists of a set of arguments interacting with each other, and from which it is possible to extract one or several consistent points of view. In this thesis, we are mainly concerned with the abstract argumentation in which arguments are handled as abstract entities whose meaning is unknown and in which the interactions represent conflicts. This allows us to focus on the particular point of the dynamics in abstract argumentation systems, that is to say the changes that could impact these systems, particularly in the context of a dialogue. We start with justifying the interest of such a formal framework, then we study the how and the why of change in abstract argumentation. The how is tackled by establishing a list of changes that an argumentation system can undergo and by studying the conditions under which they may occur. The why is addressed by introducing the notion of goal motivating a change and by choosing the best change to make in order to satisfy a goal, taking into account constraints on the agent to convince. Finally, we make our study concrete by proposing a tool that implements the concepts introduced and we study its performance

Assessing the Impact of Agents in Weighted Bipolar Argumentation Frameworks

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Four Ways to Evaluate Arguments According to Agent Engagement

International audienceIn this paper we are interested in the computational and formal analysis of the persuasive impact that an argument can have on a human. We present a preliminary account of the listener mental process (representation and reasoning mechanisms of the dual process cognitive model) as well as her engagement based on the ELM model. This engagement determines the reasoning process that the agent will adopt in order to evaluate and incorporate the uttered argument

Substantive irrationality in cognitive systems

International audienceIn this paper we approach both procedural and substantive irrationality of artificial agent cognitive systems and consider that when it is not possible for an agent to make a logical inference (too expensive cognitive effort or not enough knowledge) she might replace certain parts of the logical reasoning with mere associations

Are ranking semantics sensitive to the notion of core?

International audienceIn this paper, we study the impact of two notions of core on the output of ranking semantics in logical argumentation frameworks. We consider the existential rules fragment, a language widely used in Semantic Web and Ontology Based Data Access applications. Using burden semantics as example we show how some ranking semantics yield different outputs on the argumentation graph and its cores. We extend existing results in the literature regarding core equivalences on logical argumentation frameworks and propose the first formal characterisation of core-induced modification for a class of ranking semantics satisfying given postulates

Goal-driven Changes in Argumentation: A theoretical framework and a tool

International audienceThis paper defines a new framework for dynamics in argumentation. In this framework, an agent can change an argumentation system (the target system) in order to achieve some desired goal. Changes consist in addition/removal of arguments or attacks between arguments and are constrained by the agent’s knowledge encoded by another argumentation system. We present a software that computes the possible change operations for a given agent on a given target argumentation system in order to achieve some given goal

Changements guidés par les buts en argumentation : Cadre théorique et outil

National audienceCet article définit un cadre théorique pour étudier le changement en argumentation. Ce cadre permet de prendre en compte le raisonnement d’un agent qui désire modifier un système d’argumentation cible afin d’atteindre certains buts. Les modifications sont des ajouts/retraits d’arguments ou d’attaques. L’agent est contraint par ses propres connaissances représentées par un deuxième système d’argumentation. Nous présentons un logiciel capable de calculer les opérations exécutables par un agent pour atteindre ses buts sur une cible donnée

Argumentation update in YALLA (Yet Another Logic Language for Argumentation)

International audienceThis article proposes a complete framework for handling the dynamics of an abstract argumentation system. This frame can encompass several belief bases under the form of several argumentation systems, more precisely it is possible to express and study how an agent who has her own argumentation system can interact on a target argumentation system (that may represent a state of knowledge at a given stage of a debate). The two argumentation systems are defined inside a reference argumentation system called the universe which constitutes a kind of “common language”. This paper establishes three main results. First, we show that change in argumentation in such a framework can be seen as a particular case of belief update. Second, we have introduced a new logical language called YALLA in which the structure of an argumentation system can be encoded, enabling to express all the basic notions of argumentation theory (defense, conflict-freeness, extensions) by formulae of YALLA. Third, due to previous works about dynamics in argumentation we have been in position to provide a set of new properties that are specific for argumentation update

Towards an Understanding of Human Persuasion and Biases in Argumentation (CAF 2016)

International audienceWe present in this paper some recent work aiming at allowing the formal analysis of the persuasive impact that an argument may produce on a human agent based. We present a computational model based on the Dual Process Theory and applied to argument evaluation. These works form the preliminary step that will allow a better understanding of two crucial aspects of collective decision-making: persuasive processes and argumentation strategies