On correlation between two fuzzy sets

In this paper we investigated the correlation between two fuzzy sets defined on the same universal support. It is shown that Spearman's rank correlation coefficient can be applied if the members of the supports are ranked according to the fuzzy membership values of each set. Next a membership-value-based fuzzy correlation measure is proposed and its properties are explained. The proposed measure is compared with an earlier definition [4]. (C) 2001 Elsevier Science B.V. All rights reserved.