This paper proposes a method based on linear programming techniques to treat quasi-concave and non-concave fuzzy multi-objective programming (FMOP) problems. The proposed method initially presents a piecewise linear expression to interpreting a quasi-concave membership function. Then we 7nd the convex-type break points and transform all quasiconcave membership functions into concave functions. ...

Fuzzy controller’s design depends mainly on the rule base and membership functions over the controller’s input and output ranges. This paper presents two different approaches to deal with these design issues. A simple and efficient approach; namely, Fuzzy Subtractive Clustering is used to identify the rule base needed to realize Fuzzy PI and PD type controllers. This technique provides a mechan...

In this article, a fuzzy goal programming (GP) and method of approximation is presented for the solution of a multiobjective linear plus linear fractional programming problem. In the proposed approach, membership functions are defined for each fuzzy goal and then a method of variable change on the underand overdeviational variables of the membership functions associated with the fuzzy goals of ...

A systematic procedure for developing the unified signal flow graph model of a fuzzy PI controller is presented in this paper. From this unified model it is possible to determine the complete behavior of the Fuzzy PI controller. As a first step in constructing the signal flow graph the analytical structures oflinear fuzzy PI controller are needed. In view of this by considering triangular/trape...

In the present use of fuzzy logic systems tuning of their parameters has become an important issue. Many techniques, mainly based on the application of gradient descent, have been applied to this task generally in order to minimize a quadratic error function. The class of fuzzy logic systems using piecewise linear membership functions (e.g., triangular or trapezoidal) and/or minimum or maximum ...

This paper deals with center of sum defuzzification method via a computationally attractive method, called transformation function method. A technique for deriving the transformation functions for output fuzzy sets with trapezoidal membership functions has been introduced. It is shown that this method enormously reduces number of mathematical operations and amount of memory space required to co...

This paper presents a fuzzy goal programming FGP procedure for solving bilevel multiobjective linear fractional programming BL-MOLFP problems. It makes an extension work of Moitra and Pal 2002 and Pal et al. 2003 . In the proposed procedure, the membership functions for the defined fuzzy goals of the decision makers DMs objective functions at both levels as well as the membership functions for ...