Knowledge Patterns

Reference: P. Clark, J. Thompson and B. Porter. Knowledge Patterns. In KR'2000 (Proc 7th Int Conf), pages 591-600, Eds: A. Cohn, F. Giunchiglia, B. Selman, CA:Kaufmann, 2000.

Abstract: When building a knowledge base, one frequently repeats similar versions of general theories in multiple, more specific theories. For example, when building the Botany Knowledge Base\cite{bkb}, we embedded a theory of {\it production} in representations of {\it photosynthesis, mitosis, growth,} and many other botanical processes. Typically, a general theory is incorporated into more specific ones by an inheritance mechanism. However, this works poorly in two situations: when the general theory applies to a specific theory in more than one way, and when only a selected portion of the general theory is applicable. We address this problem with a knowledge engineering technique based on the explicit representation of {\it knowledge patterns}, ie. general templates denoting recurring theory schemata, and their transformation (through symbol renaming) to import into specific theories. This technique provides considerable flexibility. A knowledge pattern may be transformed in multiple ways, and each resulting theory can be imported in whole or in part. We describe an application built using this technique, then critique its strengths and weaknesses. We conclude that this technique enables us to better modularize knowledge-bases and to reuse their general theories.

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