Expert Systems Production Rules Predicates Distances between Predicates Analogy Reasoning
Institute of Information Theories and Applications FOI ITHEA
The purpose is to develop expert systems where by-analogy reasoning is used. Knowledge
“closeness” problems are known to frequently emerge in such systems if knowledge is represented by
different production rules. To determine a degree of closeness for production rules a distance between
predicates is introduced. Different types of distances between two predicate value distribution functions are
considered when predicates are “true”. Asymptotic features and interrelations of distances are studied.
Predicate value distribution functions are found by empirical distribution functions, and a procedure is
proposed for this purpose. An adequacy of obtained distribution functions is tested on the basis of the
χ –criterion and a testing mechanism is discussed. A theorem, by which a simple procedure of
measurement of Euclidean distances between distribution function parameters is substituted for a predicate
closeness determination one, is proved for parametric distribution function families. The proposed distance
measurement apparatus may be applied in expert systems when reasoning is created by analogy.