Simulation Based Optimization Multi Echelon Inventory system with uncertain and prioritize Demand

Inventory management is one of the key issues in the integration of supply chain components. Research has shown that when it comes to a component, supply chain management is more efficient in comparison with the independent inventory management. In this paper, a simulation model with the Arena software has been created for multilevel inventory control in the supply chain. The supply chain in question includes retailers, distribution center, manufacturer and supplier. In this paper, it is assumed that the model is multi-product with varying priority between the products. The demand and delivery parameters are uncertain here. Also, the ordering policy of all levels except the manufacturer is (r, Q). The manufacturer uses (r, R) policy due to the storage space limitations. Considering that the target supply chain is medicinal, maximizing the level of delivering service to the customers is of utmost importance. In order to demonstrate the applicability of this model, the supply chain of Samen Pharmaceutical in Mashhad has been investigated as a case study.