۱- Introduction

۲- Literature review

۳- Problem definition

۴- Model assumptions

۵- Modeling

۶- Solution approach

۷- Conclusion and future research

References

Abstract

In recent years, Supply Chain Management (SCM) has been the main focus in many industries in order to decrease costs and improve efficiencies. In today’s supply chains, sale determination for a product in a specific time period and for a specific customer is highly considered. The importance of this efficiency is increased when dealing with perishable products, such as blood, vaccine, foods, etc. These products not only have various customers, but they also must be used before perishing. This paper represents a model to determine the optimal sales level of perishable products in a two-echelon supply chain, using a Vendor Managed Inventory (VMI) policy. Based on the literature most studies have considered two-echelon supply chain for perishable products with one buyer. The proposed model is formulated based on one vendor and multiple buyers. Considering buyers’ requests in various periods, this model aims to optimize the sales profit by exact and meta-heuristics methods. Three efficient meta-heuristics including GA, PSO and CPSO are utilized to solve the problem and the results showed the good consistency with the results obtained from exact method. The obtained results show that applying VMI policy on two-echelon supply chain for perishable products is an effective approach to optimize the profitability of the proposed network.

Introduction

Perishable products have made companies consider different factors for chain management and network logistics because of their soon expiry date. Moreover, the costs of perishable products and the subsequent failure to deliver them to customers are very high. In addition, many expenditures before the product reaches to the final consumer are done, including costs relating to the manufacture, warehousing, inventory, and transportation. However, these perishable products will no longer be usable after their expiry date. To illustrate, in 2010, one state in Canada suffered a two-million-dollar financial loss over a six-month period of time because of the perished influenza vaccine H1N1. The deterioration of perishable products makes these products to be consumed within their shelf time period. This characteristic result not only in direct loss of these products, but also reduces the potential customers and the acceptability of these items. In addition, the results of studies have shown that there is a significant demand for these products in recent years and its growth (see figure 1). Fig. 1. shows value of U.S. product shipments of perishable prepared food to customers. According to the report, the value of U.S. product shipments of perishable prepared food amounted to approximately 14 billion U.S. dollars in 2016.