Title :
Problems with the defuzzification method and a new representation using Lukasiewicz logic
Author :
Kundu, Sukhamay ; Chen, Jianhua
Author_Institution :
Dept. of Comput. Sci., Louisiana State Univ., Baton Rouge, LA, USA
Abstract :
We show that the common defuzzification method has some major deficiencies in regard to certain formal logical properties among rules like AND-equivalence, contrapositive-equivalence, chaining-property, etc. To correct this problem, we present a new method for representing a function y=g(x) using a rule set based on Lukasiewicz´s logic Lℵ. The method introduces two sets of normalized fuzzy concepts {Aj: 1⩽j⩽N} and {Cj: 1⩽j⩽N}, a set of rules of the form rj=“if x is Aj then y is Cj” or “if x is ~Aj then y is Cj” where Aj and Cj have non-decreasing linear membership functions, and an AND/OR formula φ(r1, r2, ..., rN) over the rules ri, without involving negation, which describes how to combine the results of inference from the individual rules rj to obtain the final value of y. Our rules satisfy the logical properties in regard to the various equivalences when applicable
Keywords :
fuzzy logic; fuzzy set theory; inference mechanisms; knowledge based systems; knowledge representation; AND/OR formula; Lukasiewicz logic; defuzzification; fuzzy logic; fuzzy set theory; inference; linear membership functions; rule set; Computer science; Fuzzy logic; Fuzzy sets;
Conference_Titel :
Fuzzy Systems, 1995. International Joint Conference of the Fourth IEEE International Conference on Fuzzy Systems and The Second International Fuzzy Engineering Symposium., Proceedings of 1995 IEEE Int
Conference_Location :
Yokohama
Print_ISBN :
0-7803-2461-7
DOI :
10.1109/FUZZY.1995.409930