Optimal Control Polices for an Inventory Service System Based on the Queueing Theory

This paper considers an inventory service system with continuous-review( s,Q) replacement policy. The steady-state balance equations are set up based on queuing theory. And the probability distribution for inventory levels and the steady-state performance measures which are used to for the inventory control are derived. For minimizing the inventory cost function,an inventory control model with constrained service level is built. In view of the optimal model which is no-linear and constrained with integer type variables,an improved genetic algorithm( IGA) is used for searching for the optimums. The numerical results show that the inventory cost can be cut down by exerting service level constraint when target service level is greater than endogenetic service level of the inventory system.