Representing exceptions in rule-based systems
Making inferences and decisions in an imprecise and changing world limits the potential leverage of a system, particularly, in occurrence of exceptions. Many rule-based systems which make inferences using rules attempt to deal with expected exceptions by augmenting the rules in the knowledge base. The result is a whole tree of rules which widens the search space of a goal. This paper introduces several kinds of exceptions and presents a methodology for representing exceptions at the object level and meta level of rule-based systems. The proposed approach accommodates instance exceptions as well as assertion exceptions, hence allowing for the recognition of exception rules as distinct from the normal rules in rule-based systems.
Keywords and phrasesobject-level rules meta-level rules rule model exceptions
Unable to display preview. Download preview PDF.
- 1. [Christian 84]Christian, F., "On Exceptions, Failures, and Errors", Research report: RJ 4486, IBM Research Laboratory, San Jose, California, 1984. pp. 4.Google Scholar
- 2. [Davis 85]Davis,R and Buchanan, B.G., "Meta-level knowledge: Overview and Applications", in Brachman,R and Levesque,H (eds), Readings in Knowledge Representation, Morgan Kaufmann, Los Altos,1985,pp. 389–397.Google Scholar
- 3. [Duda 84]Duda, R.D. and Rebok, R., "AI and Decision Making: The PROPSECTOR Experience", Reitman, W. (ed), Artificial Intelligence Applications for Business, Ablex Publishing Corporation, 1984, pp. 136.Google Scholar
- 4. [Shortliffe 76]Shortliffe, E.H., Computer Based Medical Consultation: MYCIN, American Elsevier, New York (1976).Google Scholar
- 5. [Stefanek 87]Stefanek, G and Chang, S.K., "A methodology for rule-base integrity in expert systems", AFIPS Proc. of the National Computer Conferences, Vol. 56, (June 1987), PP. 77–85.Google Scholar
- 6. [Stachowitz 87]Stachowitz,R.A. and Combs,J.B., "Validation of Expert Systems", Proc. of the Twentieth Annual Hawaii International Conference on System Sciences, (1987), pp. 686–695.Google Scholar
- 7. [Touretzky 86]Touretzky, D.S., (1986) "The Mathematics of Inheritance Systems", Pitman Research Notes in Artificial Intelligence, Pitman Publishing Limited, London.Google Scholar
- 8. [Zadeh 83]Zadeh, E.H., "Commonsense knowledge representation based on fuzzy logic.", IEEE Computer, Oct 1983, pp. 61–65.Google Scholar