Hybrid Possibilistic Conditioning for Revision under Weighted Inputs

International audienceWe propose and investigate new operators in the possi-bilistic belief revision setting, obtained as different combinations of the conditioning operators on models and countermodels, as well as of how weighted inputs are interpreted. We obtain a family of eight operators that essentially obey the basic postulates of revision, with a few slight differences. These operators show an interesting variety of behaviors, making them suitable to representing changes in the beliefs of an agent in different contexts

Using Trust and Possibilistic Reasoning to Deal with Untrustworthy Communication in VANETs

International audienceVANETs allow for unprecedented amounts of information to be sent between participants in traffic. Unfortunately, without countermeasures, they also allow selfish agents to take advantage of communication to improve their own utility. In this paper we present a novel framework for dealing with potentially untrustworthy information. The framework consists primarily of two components: a computational trust model for estimating the amount of uncertainty in received information and a possibilistic beliefs-desires-intentions agent system for reasoning about this uncertain information in order to achieve the driver's goals. We demonstrate the framework's effectiveness in an easy to understand but realistic scenario of a freeway system in which we also show that deceit may have a larger impact on traffic flow than previously thought

A Syntactic Possibilistic Belief Change Operator: Theory and empirical study

International audienceWe propose a syntactic possibilistic belief-change operator, which operates on a belief base of necessity-valued formulas. Such a base may be regarded as a finite and compact encoding of a possibility distribution over a possibly infinite set of interpretations. The proposed operator is designed so that it behaves like a semantic possibilistic belief-change operator for BDI agents recently proposed in the literature. The equivalence of the semantic and syntactic operators is then proved. Experimental results are presented. The aim of these experiments is to demonstrate that the cost of belief revision (expressed in terms of the number of entailment checks required) as well as the size of the belief base do not explode as the number of new pieces of information (formulas) supplied increases