Similarity Measures Between Type-2 Fuzzy Sets

Abstract

As an indispensable parameter in type 2 fuzzy logic, the similarity measure has a favorable application prospect. In this paper, the research history and status of this index are discussed briefly. Several typical definitions widely concerned by scholars are researched as emphases, including similarity measures of interval type-2 fuzzy sets and those of ordinary type-2 fuzzy sets. Several successful application cases in the fields of pattern recognition, fuzzy clustering, simplification of fuzzy rule base in recent years are listed, and a simulation case of short term power load forecasting is presented to verify the performance of a similarity measure between interval type-2 fuzzy sets. Finally, the deficiency at present and the future development trend are pointed out.