Environmental Project Evaluation Using Intuitionistic Fuzzy Information

Abstract

An intuitionistic fuzzy set (IFS) is a generalization of a fuzzy set characterized by a truth membership function and a false membership function. The former is a lower bound on the grade of membership of the evidence in favor of a particular element belonging to the set and the latter is a lower bound on the negation of that element belonging to the set, derived from evidence against that element belonging to the set. A similar concept is a vague set, though vague sets have been shown to be identical to IFSs. In the context of project evaluation, an IFS may be used to represent the degree to which a project satisfies a criterion or factor and the degree to which it does not. Aggregation of such IFSs has been considered in recent years to identify a best project in terms of several factors. A particular desirable way to aggregate IFSs is in terms of an ordered weighted average (OWA) which can be expressed in different forms, such as arithmetic and geometric. In an OWA, weights are applied to the position of an element in the aggregation. In addition, hybrid OWA operators may be developed to not only weight the position of elements in the aggregation but the element itself. A simple example based on a hypothetical but realistic example by Horsak and Damico [4] is given which involves the location of a hazardous waste disposal facility (PCB-contaminated transformer fluids) at one of three sites based on 10 factors.