In the aforesaid paper, some pages are omitted reluctantly and are corrected thus. In this paper, the two-floor facility layout problem with unequal departmental areas in multi-bay environments is addressed. A mixed integer programming formulation is developed to find the optimal solution to the problem. This model determines position and number of elevators with consideration of conflicting objectives simultaneously. Objectives include to minimize material handling cost and to maximize closeness rating. A memetic algorithm (MA) is designed to solve the problem and it is compared with the corresponding genetic algorithm for large-sized test instances and with a commercial linear programming solver solution to small-sized test instances. Computational results proved the efficiency of solution procedure to the problem.
The investigated case is a vast country with a variety of climates. Due to this diversity in climate and therefore different farming conditions in different areas of the country, wheat is produced at different times of year all over the country. Therefore, wheat production rate is not constant during year all around the country. Lack of balance between wheat production and consumption in different provinces during different periods necessitates storage and transportation of wheat. In this paper, we intend to find the answer to the following question: "How much wheat in each month of year must be transported from each province to other provinces?" A mixed integer programming (MIP) model is developed for the problem and a genetic algorithm (GA) is designed because optimization solvers cannot solve the real-size problem in a reasonable time. To show efficiency, GA results are compared with those of LINGO 8.00 for randomly generated small-sized test problems.
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