Invited Speakers and Abstracts
We are delighted to announce the invited speakers at the ECSQARU 2011 conference.
A framework for information fusion and revision in qualitative and quantitative settings
Abstract: Fusion and revision are two key topics in knowledge representation and uncertainty theories. However, various formal axiomatisations of these notions were generally proposed inside specific settings, like logic, probability theory,possibility theory, kappa functions, belief functions and imprecise probability . For instance, the revision rule in probability theory is Jeffrey's rule, and is characterized by two axioms. The AGM axioms for revision are well known in the propositional logic setting. But there is no bridge between these axiomatizations. Likewise, Dempster rule of combination was axiomatized by Smets among others, and a belief set syntax-independent axiomatization for merging was independently proposed by Koniezny and Pino-Perez, while a belief function can be viewed as a random belief set. Moreover the distinction between fusion and revision is not always so clear and comparing sets of postulates for each of them can be enlightening.
This talk presents a tentative set of basic principles for revision and another set of principles for fusion that could be valid regardless of whether information is represented qualitatively or quantitatively. In short, while revision obeys a success postulate and a minimal change principle, fusion is essentially symmetric, and obeys a principle of optimism, that tries to take advantage of all sources of information. Moreover, when two pieces of information are consistent, revising one by the other comes down to merging them symmetrically. Finally, there is a principle of minimal commitment at work in to all settings, and common to the two operations. The talk will present preliminary findings along these lines.
This work is done in cooperation with Weiru Liu, Jianbing Ma and Henri Prade.
Equational Approach to Argumentation Networks
Abstract: This talk provides equational semantics for Dung´s argumentation networks. The network nodes get numerical values in [0,1], and are supposed to satisfy certain equations. The solutions to these equations correspond to the extensions of the network.
This approach is very general and includes the Caminada labelling as a special case, as well as many other so-called network extensions, support systems, higher level attacks, Boolean networks, logic programs as networks, dependence on time, etc, etc. Special attention will be paid to implications to conflict resolution through equations, as the connection between argumentation networks and logic programs is well known.
Abstract: The standard approach in decision theory (going back to Savage) is to place a preference order on acts, where an act is a function from states to outcomes. If the preference order satisfies appropriate postulates, then the decision maker can be viewed as acting as if he has a probability on states and a utility function on outcomes, and is maximizing expected utility. This framework implicitly assumes that the decision maker knows what the states and outcomes are. That isn't reasonable in a complex situation. For example, in trying to decide whether or not to attack Iraq, what are the states and what are the outcomes? We redo Savage viewing acts essentially as syntactic programs. We don't need to assume either states or outcomes. However, among other things, we can get representation theorems in the spirit of Savage's theorems; for Savage, the agent's probability and utility are subjective; for us, in addition to the probability and utility being subjective, so is the state space and the outcome space. I discuss the benefits, both conceptual and pragmatic, of this approach. As I show, among other things, it provides an elegant solution to framing problems.
This is joint work with Larry Blume and David Easley. No prior knowledge of Savage's work is assumed.