When merging belief functions, Dempster rule of combination is justified only when information sources can be considered as independent. When this is not the case, one must find out a cautious merging rule that adds a minimal amount of information to the inputs. Such a rule is said to follow the principle of minimal commitment. Some conditions it should comply with are studied. A cautious mergi...

User modeling is an iml>ortant COlnponents of dialog systems. Most previous approaches are rule-based methods, hi this paper, we proimse to represent user models th rough Bayesian networks. Some advantages of the Bayesian approach over the rule-based approach are as follows. First, rules for upda t ing user models are not necessary because up<lating is directly performed by the ewduation of the...

One of the key challenges in designing expert systems is a credible representation of uncertainty and partial belief. During the past decade, a number of rule-based belief languages were proposed and implemented in applied systems. Due to their quasi-probabilistic nature, the external validity of these languages is an open question. This pape~ discusses the theory of belief revision in expert s...

Description of the transferable belief model to quantify degrees of belief, based on belief functions. The impact of open-and closed-world assumption on conditioning. Presentation of a set of axioms justifying Dempster's rule for the combination of belief functions induced by 2 distinct evidences.

We show that Booth et al.’s Horn contraction based on infra-remainder sets corresponds exactly to kernel contraction for belief sets. This result is obtained via a detour through Horn contraction for belief bases, which supports the conjecture that Horn belief change is best viewed as a “hybrid” version of belief set change and belief base change. Moreover, the link with base contraction gives ...

Agents which perform inferences on the basis of possibly unreliable information need an ability to revise their beliefs if they discover an inconsistency. However, most belief revision algorithms for classical reasoners have quite high complexity, which makes them unsuitable for resource-bounded reasoners. We consider belief revision for agents which reason in a simpler logic that the full firs...

The update of a belief database with disjunctive knowledge which is contradictory with the beliefs of an agent poses some problems when we want to perform belief-revision with minimal changes. We define a representation of beliefs based on rules. Clauses have already been used to represent beliefs. We combine them with defaults, which allows a simple treatment of disjunctive beliefs. The behavi...

The AGM postulates for knowledge base revision are a set of rationality postulates that revision operations on knowledge systems should satisfy. Deening an appropriate semantics for belief revision that satisses all of the postulates has been considered a challenging problem. In this paper we present a novel application of circumscription to deening a semantics of belief revision systems. First...