A Conviviality Measure for Early Requirement Phase of Multiagent System Design

in Normative Multi-agent Systems (2009)

Time and Defeasibility in FIPA ACL Semantics

in Proceedings of WLIAMAS 2008 (2008)

Inferences about speech acts are often conditional, nonmonotonic, and involve the issue of time. Most agent communication languages, however, ignore these issues, due to the difficulty to combine them in ... [more ▼]

Inferences about speech acts are often conditional, nonmonotonic, and involve the issue of time. Most agent communication languages, however, ignore these issues, due to the difficulty to combine them in a single formalism. This paper addresses such issues in defeasible logic, and shows how to express a semantics for ACLs in order to make nonmonotonic inferences on the basis of speech acts. [less ▲]

Making Others Believe What They Want

in Artificial Intelligence in Theory and Practice II, IFIP 20th World Computer Congress, TC 12: IFIP AI 2008 Stream (2008)

We study the interplay between argumentation and belief revision within the MAS framework. When an agent uses an argument to persuade another one, he must consider not only the proposition supported by ... [more ▼]

We study the interplay between argumentation and belief revision within the MAS framework. When an agent uses an argument to persuade another one, he must consider not only the proposition supported by the argument, but also the overall impact of the argument on the beliefs of the addressee. Different arguments lead to different belief revisions by the addressee. We propose an approach whereby the best argument is defined as the one which is both rational and the most appealing to the addressee. [less ▲]

Substantive and procedural norms in normative multiagent systems

in Journal of Applied Logic (2008), 6(2), 152171

Procedural norms are instrumental norms addressed to agents playing a role in the normative system, for example to motivate these role playing agents to recognize violations or to apply sanctions ... [more ▼]

Procedural norms are instrumental norms addressed to agents playing a role in the normative system, for example to motivate these role playing agents to recognize violations or to apply sanctions. Procedural norms have first been discussed in law, where they address legal practitioners such as legislators, lawyers and policemen, but they are discussed now too in normative multiagent systems to motivate software agents. Procedural norms aim to achieve the social order specified using regulative norms like obligations and permissions, and constitutive norms like counts-as obligations. In this paper we formalize procedural, regulative and constitutive norms using input/output logic enriched with an agent ontology and an abstraction hierarchy. We show how our formalization explains Castelfranchi's notion of mutual empowerment, stating that not only the agents playing a role in a normative system are empowered by the normative system, but the normative system itself is also empowered by the agents playing a role in it. In our terminology, the agents are not only institutionally empowered, but they are also delegated normative goals from the system. Together, institutional empowerment and normative goal delegation constitute a mechanism which we call delegation of power, where agents acting on behalf of the normative system become in charge of recognizing which institutional facts follow from brute facts. [less ▲]

Institutions with a hierarchy of authorities in distributed dynamic environments

in Artificial Intelligence and Law (2008), 16(1), 5371

A single global authority is not sufficient to regulate heterogenous agents in multiagent systems based on distributed architectures, due to idiosyncratic local situations and to the need to regulate new ... [more ▼]

A single global authority is not sufficient to regulate heterogenous agents in multiagent systems based on distributed architectures, due to idiosyncratic local situations and to the need to regulate new issues as soon as they arise. On the one hand institutions should be structured as normative systems with a hierarchy of authorities able to cope with the dynamics of local situations, but on the other hand higher authorities should be able to delimit the autonomy of lower authorities to issue valid norms. In this paper, we study the interplay of obligations and strong permissions in the context of hierarchies of authorities using input/output logic, because its explicit norm base facilitates reasoning about norm base maintenance, and it covers a variety of conditional obligations and permissions. We combine the logic with constraints, priorities and hierarchies of authorities. In this setting, we observe that Makinson and van der Torre’s notion of prohibition immunity for permissions is no longer sufficient, and we introduce a new notion of permission as exception and a new distinction between static and dynamic norms. We show how strong permissions can dynamically change an institution by adding exceptions to obligations, provide an explicit representation of what is permitted to the subjects of the normative system and allow higher level authorities to limit the power of lower level authorities to change the normative system [less ▲]

Desirable Tie-breaking Rules in Collective Decision Making

in Annales du LAMSADE (2008)

Judgment aggregation (JA) studies how to aggregate individual judgments to form collective decisions. Examples are expert panels, legal courts, boards, and councils. The problems investigated in this new ... [more ▼]

Judgment aggregation (JA) studies how to aggregate individual judgments to form collective decisions. Examples are expert panels, legal courts, boards, and councils. The problems investigated in this new field are relevant and common to many situations. Nevertheless, the existing procedures are idealized and, likewise the related problems of preference aggregation in social choice theory, the field is plagued by impossibility theorems. In this paper, we extend standard JA in order to offer a more realistic framework and to escape the impossibility results. We propose to distinguish between abstainers and neutral judgment as well as to model the notion of confidence a group member may have in the decision rule by assigning to each criterion a normalized weight. We then show how this new framework may help us to avoid indecision in most cases. [less ▲]

Conviviality masks in multiagent systems

in Conviviality Masks in Multiagent Systems (2008)

In this paper we study tools for conviviality to develop user-friendly multiagent systems. First, we show how to use the social-cognitive concept of conviviality in multiagent system technology by ... [more ▼]

In this paper we study tools for conviviality to develop user-friendly multiagent systems. First, we show how to use the social-cognitive concept of conviviality in multiagent system technology by relating it to agent power and social dependence networks. Second, we de- fine conviviality masks as transformations of social dependencies by hiding power relations and social structures to facilitate social interactions. Third, we introduce dynamic dependence networks to model the creation of conviviality using conviviality masks. We illustrate the use of conviviality masks with a multiagent telecon- ferencing application for virtual worlds. [less ▲]

E-business Outsourcing: a New Approach combining Information Rights Technologies and Agent-Based Theory on Norms

in Proceedings of the International Conference on Electronic Commerce in the 21th Century (ECIC-2008) (2008)

Conclusion-based procedure for judgment aggregation satisfying premise independence

in Proceedings of the Eighth International Conference on Logic and the Foundations of Game and Decision Theory, LOFT 2008 (2008)

Judgment aggregation is a formal theory reasoning about how a group of agents can aggregate individual judgments on connected propositions into a collective judgment on the same propositions. Three ... [more ▼]

Judgment aggregation is a formal theory reasoning about how a group of agents can aggregate individual judgments on connected propositions into a collective judgment on the same propositions. Three procedures for successfully aggregating judgments sets are: premise-based procedure, conclusion-based procedure and distance-based merging. The conclusion-based procedure has been little investigated because it pro- vides a way to aggregate the conclusions, but not the premises, thus it outputs an incomplete judgment set. The goal of this paper is to present a conclusion-based procedure outputting complete judgment sets. [less ▲]

Conditional norms and dyadic obligations

in Proceedings of Eighteenth European Conference on Artificial Intelligence (ECAI2008) (2008)