A New mathematical Model for Stochastic Dynamic Unequal Area Facility Layout Problems

Document Type : Research Paper


Department of Industrial Engineering, Faculty of Industrial and Mechanical Engineering, Qazvin Branch, Islamic Azad University, Qazvin, Iran.



Organizing the positions of facilities or departments in a given area is categorized as a facility layout problem. This research has formulated unequal area stochastic dynamic facility layout problems in order to minimize the sum of the material handling costs while considering their upper bound, i.e. minimizing the upper bound of the sum of the material handling costs, and the sum of the shifting costs in the whole time planning horizon. In the proposed model, the area and shape of each department are stable during the implementation of an algorithm, while product demands are normally distributed with a known expected value and variance. This type of problems is very complex and NP-hard; therefore, meta-heuristic approaches must be employed to solve them. In this article,particle swarm optimization (PSO) was proposed and a theoretical problem instances were presented to evaluate the efficiency and effectiveness of the algorithm. The results manifested efficiency and validity of the proposed algorithm.