Catálogo de publicaciones - libros

This paper presents a novel approach to modelling embedded agent dialogues. It proposes a specific structure for the supporting information accompanying the arguments that agents exchange during a dialogue, it defines formally how this information relates to the agent theory, and assigns to it semantics that is associated to each of the atomic dialogue types of the Walton-Krabbe typology. This allows the formal definition of necessary and sufficient initiation and acceptance conditions of licit dialectical shifts that are necessary for the modelling of embedded agent dialogues.

This paper proposes a liberalized version of existing truth-finding protocols for argumentation, such as the standard two-agent immediate-response protocol for computing the credulous acceptance of conclusions in an argument system. In the new setup agents decide autonomously which issues need to be discussed, when to query other agents, when to keep on querying other agents, and when to settle for an answer. In this way, inter-agent disputes are regulated by the agents themselves, rather than by following an outlined protocol. The paper concludes with a prototype implementation and with a comparison of related work on conversation analysis and computational dialectic.

Inspired by computational linguistic approaches to annotate the structures that occur in human dialogue, this paper describes a technique which encodes these structures as transformations applied to a protocol language. Agents can have a controlled and verifiable mechanism to synthesise and communicate their interaction protocol during their participation in a multiagent system. This is in contrast to the approaches where agents must subscribe to a fixed protocol and relinquish control over an interaction that may not satisfy the agent’s dialogical needs or rely on internal its reasoning to determine which message to communicate at a certain point in the dialogue.

Autonomous agents working in multi-agent environments need to cooperate in order to fulfill tasks. Generally, an agent cannot perform a task alone and needs help from the other agents. One of the solutions to this problem is to look for groups of agents which are able to perform the desired tasks better. Different algorithms have then been proposed for the task allocation via coalition formation. This last is generally seen as a two steps process: i) constructing the different solutions (called coalitions structures), then ii) discussing these solutions between the agents in order to select the best ones which will be adopted.

This paper provides a unified formal framework for constructing the coalitions structures. In fact, we will show that the problem of coalition formation can be defined in terms only of whose structures are abstract, a relationship between the coalitions and a preference relation between the coalitions. Three semantics for coalitions structures will be proposed: a basic semantics which will return a unique coalition structure, stable semantics and preferred semantics. These two last may return several coalitions structures at the same time. A proof theory of the basic semantics will also be proposed. The aim of this proof theory is to test whether a given coalition will be acceptable for the agent or not without computing the whole structure. We will show that this framework is general enough to capture different propositions made in the literature. An instantiation of our framework is given and its properties are studied.

This paper presents an argumentation-based approach to deliberation, the process by which two or more agents reach a consensus on a course of action. The kind of deliberation that we are interested in is a process that combines both the selection of an overall goal, the reduction of this goal into sub-goals, and the formation of a plan to achieve the overall goal. We develop a mechanism for doing this, describe how this mechanism can be integrated into a system of argumentation to provide a sound and complete deliberation system, and show how the same process can be achieved through a multi-agent dialogue.

A key goal for a scientist is to find evidence to argue for or against universal statements (in effect first-order formulae) about the world. Building logic-based tools to support this activity could be potentially very useful for scientists to analyse new scientific findings using experimental results and established scientific knowledge. In effect, these logical tools would help scientists to present arguments and counterarguments for tentative scientific knowledge, and to share and discuss these with other scientists. To address this, in this paper, we explain how tentative and established scientific knowledge can be represented in logic, we show how first-order argumentation can be used for analysing scientific knowledge, and we extend our framework for evaluating the degree of conflict arising in scientific knowledge. We also discuss the applicability of recent developments in optimizing the impact and believability of arguments for the intended audience.

This paper aims at proposing a general formal framework for dialogue between autonomous agents which are looking for a common agreement about a collective choice. The proposed setting has three main components: the agents, their reasoning capabilities, and a protocol. The agents are supposed to maintain beliefs about the environment and the other agents, together with their own goals. The beliefs are more or less certain and the goals may not have equal priority. These agents are supposed to be able to make decisions, to revise their beliefs and to support their points of view by arguments. A general protocol is also proposed. It governs the high-level behaviour of interacting agents. Particularly, it specifies the legal moves in the dialogue. Properties of the framework are studied. This setting is illustrated on an example involving three agents discussing the place and date of their next meeting.

Disseminating pieces of knowledge among the members of large organizations is a well known problem in Knowledge Management, involving several decision-making processes. The JITIK multiagent framework has been successfully used for just-in-time delivering highly customized notifications to the adequate users in large distributed organizations. However, in JITIK as well as in other similar approaches it is common to deal with incomplete information and conflicting policies, making difficult to make decisions about whether to deliver or not a specific piece of information or knowledge on the basis of a rationally justified procedure. This paper presents an approach to cope with this problem by integrating JITIK with a defeasible argumentation formalism. Conflicts among policies are solved on the basis of a dialectical analysis whose outcome determines whether a particular information item should be delivered to a specific user.

In our previous work on dialogue games for agent interaction, an agent’s set of beliefs (Σ) and an agent’s “commitment store” () — the set of locutions uttered by the agent — play a crucial role. The usual assumption made in this work is that the set of beliefs is static through the course of a dialogue, while the commitment store is dynamic. While the assumption of static beliefs is reasonable during the progress of the dialogue, it seems clear that some form of belief change is appropriate once a dialogue is complete. What form this change should take is our subject in this paper.