An Alternative Semantics for Argumentative Systems

Defeasible argumentation is one of the approaches that addresses the challenges arising when we reason defeasibly, with several formalisms in the literature reaching a mature state. Considering that most of these theories eventually shifted their semantics towards dialectical characterizations, we believe that a sufficiently generic model of the process of reasoning in dialectical terms could also serve as an abstract model of what happens inside an argumentative system. To that end, we develop in this article a formal model of dialectical reasoning and explore its role as an alternative semantics for argumentation theories

Modeling multiagent deliberation from an abstract standpoint

Simply put, a multiagent system can be understood as a collection of autonomous agents able to accomplish as a whole goals beyond the capabilities of any of its members. The traditional example depicts a heavy armchair that can be easily lifted by coordinating the effort of a group of persons despite that none of them would have been able to pick it up alone. Thus, one might argue that precisely the agent interaction is boosting the system performance. Since this interaction comes in several flavors, the literature has already explored notions such as agent coordination, cooperation, and collaboration in the context of multiagent systems. This extended abstract outlines our own understanding on this matter, summarizing the evolution of an abstract model for the particular kind of agent interaction known as deliberation. A group of agents deliberate whenever they need to come to a mutually accepted position about some issue. This interaction among agents has drawn our attention given its ubiquity: we believe that complex interactions such as coordination or cooperation might be attained as a result of accruing one or more deliberations. Our proposal is inspired after the novel trend of reinterpreting agent interaction as if it were the result of an argumentation process. For instance, several authors [2,3,5,13,14] have recently considered recasting the main aspects of multiagent negotiation in terms of defeasible argumentation. We follow a like approach in developing our model after a set of dialectical concepts borrowed from that same area. Our approach also strives for generality, mainly after Dung's ample success with his notion of argumentative framework due to its abstract nature. In consequence, we too have decided to pursue an abstract model.Eje: Inteligencia Artificial Distribuida, Aspectos Teóricos de la Inteligencia Artificial y Teoría de la ComputaciónRed de Universidades con Carreras en Informática (RedUNCI

Towards a semantics for argumentative systems

Defeasible argumentation is one of the approaches that attempt to address the challenges arising when we reason defeasibly, with several formalisms in the literature reaching a mature state. Nowadays, several of them started shifting their semantics towards a dialectical characterization. Therefore, we believe that a sufficiently generic model of the process of dialectical reasoning could also serve as an abstract model of what happens inside an argumentative systems. To that end, in this article we lay the foundations required for such a generic model, proposing a line of research whose central objective is attaining that abstract semantics for argumentative systems.Eje: Agentes y Sistemas InteligentesRed de Universidades con Carreras en Informática (RedUNCI

Formalizing processes in defeasible argumentation using labeled deductive systems

This paper summarizes the main results developed in the author's PhD Thesis. The main goal of the Thesis is to provide a formalization of defeasible argumentation oriented towards its computational treatment. In order to do this, an LDS-based logical framework for defeasible argumentation called LDSar has been developed. The object language is that of logic programming, complemented with labels that identify distinguished elements for representing knowledge and performing inference.Resumen de la tesis doctoral presentada por el autor en la Universidad del Sur.Facultad de Informátic

An abstract model for the process of deliberation within multiagent systems

A multiagent system is no more than a collection of interacting autonomous agents. However, this interaction allows the system as a whole to perform tasks beyond the reach of its individual members. This clearly accounts for the boost in research geared towards pro tting from this interaction. Accordingly, this paper addresses the formal modeling of a common kind of interaction known as deliberation. Simply put, a group of agents deliberate whenever they need to come to a mutually accepted position on some matter. The proposed model stems from the newly developed trend of reinterpreting agent interactions as an exchange of arguments in the context of some theory of defeasible argumentation.Eje: Sistemas inteligentesRed de Universidades con Carreras en Informática (RedUNCI

Dialogue Games in Defeasible Logic

In this paper we show how to capture dialogue games in Defeasible Logic. We argue that Defeasible Logic is a natural candidate and general representation formalism to capture dialogue games even with requirements more complex than existing formalisms for this kind of games. We parse the dialogue into defeasible rules with time of the dialogue as time of the rule. As the dialogue evolves we allow an agent to upgrade the strength of unchallenged rules. The proof procedures of (Antoniou, Billington, Governatori, Maher 2001) are used to determine the winner of a dialogue game

Is Defeasible Logic Applicable?

In this paper the application of defeasible logic for automated negotiation is investigated. Defeasible logic is flexible enough to be adapted to several possible negotiation strategies, has efficient implementations, and provides a formal basis for analysis (e.g. to explain why a negotiation was not successful). Two case studies, one small and one more comprehensive, will be described and the feasibility of approaches based on defeasible logic will be discussed