Developing a mathematical model for vendor managed inventory considering deterioration and amelioration items in a three-level supply chain

Todays, improving the competitiveness of companies and rapidly respond to diverse customer demands require efficient management of the supply chain. One of the effective indices in supply chain is integration and one of the innovative approaches in this field is Vendor Managed Inventory. In this paper, an integrated model based on vendor managed inventory system for deterioration and amelioration items in a three-level supply chain is developed. To coordinate retailers and producers in the supply chain the common replenishment cycle is used that is a technique of VMI system. The assumptions of this model consist of deterministic demand rate for each retailer, certain production and deterioration rates. Furthermore, in this paper the amelioration of items is mentioned that follow the Weibull distribution. First, the mixed integer non linear mathematical model is presented. Second, to validate the proposed model, a numerical example is given. To solve the model, genetic algorithm method is presented.