چكيده به لاتين
Abstract
Today, because of the potential of the used products, reverse logistics network are very important. As well as growing concerns about environmental and resource constraints, the importance of reuse and recycling of old products are considered. Reverse logistics are in the spotlight of organizations and researchers more than ever, for various reasons including widespread economic interests, environmental laws, etc. in this study, Multi-products, Multi-echelon and Two-Objective reverse logistics is investigated. Also in this study, reverse logistics network will be modeled using Mixed Integer Linear Programming (MILP). In this model, resuscitation options of repair, recycle and regeneracy and as well as the capacity minimum and capacity maximum of the centers is considered simultaneously. The proposed model has two objective functions which in addition to minimizing costs is seeks to minimize the amount of delay time to arrive products that need to be repaired and minimize the amount of delay time of re-manufactured products to reach consumers. It should be noted that This work is realized both through customers' areas and through centers of Sale of Products used. then for validation, solved reverse logistics Two-Objective model for Sam Service's Two types of TV and vacuum cleaner products by combination of method of sum of weighting coefficients and the Lp-Metric method for various weights by the GAMS software. first solved the model in single-product (TV) mode and then in single-product (vacuum cleaner) mode and finally in two-product mode by the GAMS software. Therefore, solved the model in each mode with regards to various weights That are the weighting factors considered by the decision maker for the purposes and plotted the graph of the optimal values of the objective functions for different weights. with regards to minimization of Both objective functions, these graphs declined. This means that when the optimal value of the first objective function is greater (worse), the optimal value of the second objective function will be less (better) and finally, we saw that by reducing the rate of sending the products from the collection center to the repair center, simultaneously, the values of the first objective function (total cost) would be better for different weights and the values of the objective function (delay time) for different weights would be worse.
Keywords:
Two-objective modeling, GAMS, Reverse Logistics, place of sale of secondhand product, Lp-Metric method, resuscitation options, sum of Weight coefficients
