Yarı-İstenen Tesis Yerleşim Problemleri İçin İki Amaçlı Yaklaşımlar

Abstract

A facility is defined as a semi-desirable facility if its location is required to be both close to the surrounding points and far away due to the undesirable effects it creates. In this thesis, a bi-objective semi-desirable facility location problem is addressed. The first objective function minimizes the transportation costs between the facility we plan to place and the demand points. It is assumed that the transportation cost is proportional to the rectilinear distance between the facility and the demand points. The second objective function represents the undesirable effects of the facility and it minimizes the social cost, which is a function of the Euclidean distance between the facility and the demand points. In this study, the second objective function is considered in two different ways. In the first problem type, the largest social cost of the facility is minimized. In the second problem type, the total social cost of the facility is minimized. New solution approaches are developed for both problem types and the Big Square Small Square (BSSS) algorithm, which searches for a solution by reducing the feasible area, is adapted to the problems. By dividing the solution area into subregions some regions can be easily eliminated and removed from the solution set. For this purpose, smaller-sized mathematical models and problem-specific approaches that evaluate the subregions are developed. A representative set of efficient solutions are obtained from the reduced regions. Both approaches are tested on two large data sets. The results show that the representative solution sets are obtained in reasonable times by reducing the possible areas.