The ADI Project: Anytime Default Inference

Department of Business Systems, University of Wollongong

Project Outline

Default reasoning approaches play a fundamental role in a variety of knowledge processing applications. Default inference, is inherently computationally hard and practical applications, especially time-bounded ones, may require that some notion of approximate inference be used. Any approximation algorithm must provide useful partial results and the trade-offs involved must be clearly identified. Approximate default inference has received scant attention in the literature. Notable exceptions include the work of Cadoli and Schaerf in which they improve on the complexity of reasoning with Reiter's default logic by using consequence relations that are sound and incomplete in one case and complete but unsound in the other), the recent results of Etherington and Crawford involving using limited contexts and fast incomplete consistency checks as well as the earlier work of Perlis. Motivated by such deficiencies in the state-of-the-art, this project seeks to develop a system for approximate default inference by means of anytime algorithms. Real-time algorithms are usually designed to satisfy a variety of application-specific requirements: some are required to provide partial, but useful results whenever they are stopped while others have the additional requirement that their partial results improve with time. Anytime algorithms are a useful conceptualization of processes that may be prematurely terminated whenever necessary to return useful partial answers, with the quality of the answers improving in a well-defined manner with time. Dean and Boddy define an anytime algorithm to be one which: The broad goals of this project are to define, implements and test anytime algorithms for default inference.

This paper discusses some of these issues in greater detail.

Funding

Post-Graduate Research Opportunities

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Contact Information

Direct enquiries to Dr. Aditya K. Ghose .