Pragmatics of Default Reasoning and Theory Change

Grigoris Antoniou, Abhaya Nayak and Aditya Ghose

Course Description

It is becoming increasingly apparent that the design of robust information systems must rely on principled methods for handling incomplete and changing information. As a result, there has been a resurgence of interest in the areas of nonmonotonic reasoning and theory change, focussing less on purely theoretical insights, and more on their ability to provide a starting point for the design of the next generation of tools for developing and managing complex information systems. This tutorial will explain what these core technologies are, why they are central to the development of real-world information systems and how they can be effectively deployed.

The tutorial will first present the formal principles underlying default reasoning, an approach to nonmonotonic reasoning which has been widely applied, and the logic of theory change. Using this formal background, the tutorial will examine applications of these techniques in a variety of domains, including diagnostic systems, intelligent scheduling systems, information retrieval and software engineering (requirements engineering, software maintenance). The tutorial will involve simple hands-on demonstrations using implemented systems for default reasoning and theory change.

Two sets of recent developments make this tutorial particularly timely. First, a number of recent studies have shown that a unified view of theory change and default reasoning leading to efficient implementations is possible. Second, an increasing number of useful applications of these technologies are being reported in the literature that build on these formal results. A clear understanding of the what, why and how of these issues is thus crucial for both researchers and practitioners interested in intelligent real-world information systems.

Prerequisite Knowledge

No prior knowledge is needed other than a basic understanding of classical logic.

About the Lecturers

Grigoris Antoniou is Senior Lecturer in Computing at Griffith University. His research interests include the logical foundations of computer science and artificial intelligence, and in particular nonmonotonic reasoning. He is co-author of "Logic: A Foundation for Computer Science", Addison-Wesley 1991, and author of a forthcoming book on Nonmonotonic Reasoning (MIT Press, 1997). He has published over 50 refereed papers at conferences and journals (including IJCAI, AAAI, Annals of Mathematics & Artificial Intelligence, Artificial Intelligence Review, Journal of Automated Reasoning).

Abhaya Nayak is a Senior Research Fellow at the Knowledge Systems Group, University of New South Wales. His research interests include belief dynamics, commonsense reasoning and counterfactual reasoning. He has published over a dozen papers in reputed journals (e.g. Journal of Philosophical Logic, Erkenntnis, Synthese) and conference proceedings. He holds a Ph.D. from the University of Rochester, U.S.A. and has held short-term teaching appointments at the University of Rochester and the State University of New York.

Aditya Ghose is Lecturer in Business Information Systems at the University of Wollongong, Australia. His research interests include default reasoning, theory change and constraint solving, and their applications in software engineering, planning and induction. He holds a Ph.D. in Computing Science from the University of Alberta, Canada. He has held research appointments with the Knowledge Systems Group at the University of Sydney and with the School of Computing at Griffith University, Brisbane and has been been a visiting researcher at the University of Tokyo.

Last modified: Thu Feb 20 14:12:53 JST 1997