Modeling a bi-objective production problem with remanufacturing the defects within queuing approach

In this paper, a production facility with independent workstations to remanufacture nonconforming products is investigated. Each workstation is first modeled as an M/M/m/V queuing system with m and V being a decision variables. Then, a bi-objective integer nonlinear programming model is developed to find optimum number of machines and capacity of each workstation. The objectives considered are: (1) minimization of the total waiting times of products and (2) minimization of the mean idle time of the machines. Since the developed model of the problem is of an NP-hard type, the non-dominated sorting genetic algorithm-II (NSGA-II) is utilized to find Pareto fronts. Because there is no benchmark available in the literature to validate the results obtained, the performance of NSGA-II is statistically compared with one of the other common meta-heuristics called non-dominated ranked genetic algorithm (NRGA). The performances of the algorithms are statistically compared using the t test. Besides, the multiple attribute decision-making method of TOPSIS is used to determine the better algorithm.

Keywords:

Remanufacturing , Queuing theory , NSGA-II , TOPSIS