Solving a bi-objective four-echelon supply chain by the STEM method

This paper presents a bi-objective mathematical model for a four-echelon supply chain, including suppliers, producer, distributors and retailers. This model finds the flow among the different levels of the supply chain that minimizes the total cost of the supply chain and maximizes the service level under some restrictions in order to trade-off and justify the obtained solutions. Then, by using a numerical example, the presented model is solved by the STEM method and LINDO software. Finally, the flow among the different levels of the supply chain and the related objective function values are reported.