Lexicographic Methods for Fuzzy Linear Programming

Abstract

Fuzzy Linear Programming (FLP) has addressed the increasing complexity of real-world decision-making problems that arise in uncertain and ever-changing environments since its introduction in the 1970s. Built upon the Fuzzy Sets theory and classical Linear Programming (LP) theory, FLP encompasses an extensive area of theoretical research and algorithmic development. Unlike classical LP, there is not a unique model for the FLP problem, since fuzziness can appear in the model components in different ways. Hence, despite fifty years of research, new formulations of FLP problems and solution methods are still being proposed. Among the existing formulations, those using fuzzy numbers (FNs) as parameters and/or decision variables for handling inexactness and vagueness in data have experienced a remarkable development in recent years. Here, a long-standing issue has been how to deal with FN-valued objective functions and with constraints whose left- and right-hand sides are FNs. The main objective of this paper is to present an updated review of advances in this particular area. Consequently, the paper briefly examines well-known models and methods for FLP, and expands on methods for fuzzy single- and multi-objective LP that use lexicographic criteria for ranking FNs. A lexicographic approach to the fuzzy linear assignment (FLA) problem is discussed in detail due to the theoretical and practical relevance. For this case, computer codes are provided that can be used to reproduce results presented in the paper and for practical applications. The paper demonstrates that FLP that is focused on lexicographic methods is an active area with promising research lines and practical implications.

Reinstatement of the Extension Principle in Approaching Mathematical Programming with Fuzzy Numbers

“…Perez-Canedo et al [37] surveyed the literature on fuzzy linear programming, paying attention to those papers that used a lexicographic method to rank the fuzzy numbers. Their up-to-date review shows that fuzzy LP relying on lexicographic methods is an active research area with a wide range of applications in practice.…”

Impacts of Emissions Trading on a Company Under Uncertain Multi-Period Environment

“…1 (1) The first group uses ranking functions (indices) mapping each fuzzy set to the real (crisp) number (see, e.g. the possibilistic mean by [17], Yager index by [18], Order Weghted Averaging (OWA) operators [19], lexicographic criteria [15], or Maleki's index [20]. The advantage of these ranking functions is that they are quite easy to use and does not require any further input parameter from a decision-maker.…”

“…For the sake of completeness, many other extensions of the fuzzy linear programming exist, like fuzzy programming with fuzzy variables[15], flexible fuzzy programming where a decision-maker expresses the satisfaction with which the goal is met, or a constrain holds[16], etc.…”

Setting up Waiting Time Targets for Out Patients using Fuzzy Linear Programming

“…Very recently, fuzzy linear programming with triangular fuzzy numbers is used to solve business problems (8) . Lexicographic approach was used to study the fuzzy linear programming in (9) . In the work (10) , the mathematical model of fuzzy linear programming was studied, and then under the restriction of elastic constraints, the objective functions were optimized.…”