Keynote Presentations

Dr. Umberto Straccia

Umberto Straccia is a researcher at the Istituto di Scienze e di Tecnologie dell'Informazione (ISTI) of the Italian National Council of Research (CNR). He received his Ph.D. in Computer Science from the University of Dortmund (Germany). His research interests include knowledge representation and reasoning; semantic web technologies; information retrieval; logic programming; and nonmontonic, many valued, and fuzzy logic.

Website: http://gaia.isti.cnr.it/~straccia/

Keynote Presentation: Fuzzy Logic, Annotation Domains and Semantic Web Languages

Abstract: The aim of this talk is to present a detailed, self-contained and comprehensive account of the state of the art in representing and reasoning with fuzzy knowledge in Semantic Web Languages such as triple languages RDF/RDFS, conceptual languages of the OWL 2 family and rule languages, such as RIF~ and discuss some implementation related issues.

We further show to which extend we may generalise them to so-called annotation domains, that cover also e.g. temporal, provenance and trust extensions.

Dr. Joe Halpern

Dr. Joe Halpern is the chair of the Department of Computer Science at Cornell University. He received a Ph.D. in mathematics from Harvard University. His research interests include reasoning about knowledge and uncertainty, qualitative reasoning, belief revision, (fault-tolerant) distributed computation, modal logic, game theory, decision theory, and security.

Webpage: http://www.cs.cornell.edu/home/halpern/

Keynote Presentation: Causes and Explanations: A Structural-Model Approach

Abstract: What does it mean that an event C ``actually caused'' event E? The problem of defining actual causation goes beyond mere philosophical speculation. For example, in many legal arguments, it is precisely what needs to be established in order to determine responsibility. (What exactly was the actual cause of the car accident or the medical problem?) Actual causation is also important in artificial intelligence applications. Whenever we undertake to explain a set of events that unfold in a specific scenario, the explanation produced must acknowledge the actual cause of those events.

The philosophy literature has been struggling with the problem of defining causality since the days of Hume, in the 1700s. Many of the definitions have been couched in terms of counterfactuals. (C is a cause of E if, had C not happened, then E would not have happened.) However, all the previous definitions have been shown (typically by example) to be problematic. We propose here new definitions of actual cause, using Pearl's notion of structural equations to model counterfactuals. We show that these definitions yield a plausible and elegant account of causation and explanation that handles well examples which have caused problems for other definitions and resolve major difficulties in the traditional account. This is joint work with Judea Pearl.