application of queuing theory in inventory systems with substitution flexibility

Considering the competition in today’s business environment, tactical planning of a supply chain becomes more complex than before. in many multi-product inventory systems, substitution flexibility can improve profits. this paper aims to prepare a comprehensive substitution inventory model, where an inventory system with two substitute products with ignorable lead time has been considered, and effects of simultaneous ordering have been examined. in this paper, demands of customers for both of the products have been regarded as stochastic parameters, and queuing theory has been used to construct a mathematical model. the model has been coded by c++, and it has been analyzed due to a real example, where the results indicate efficiency of proposed model.