Stochastic inventory model with one sort of time-critical products in case of uncertain demand and constant supply

Using the idea and method of queuing theory, the stochastic inventory model is established presented in form of state probability for the time-critical products, in which the supply intensity is constant but to be determined, the demand intensity is known already, but the demand quantity is stochastic. By transforming the state probability equations into matrix equations, we get a general computing method, so the approximate optimal supply intensity can be computed when the demand intensity is known. At the end of the paper, a practical example is studied and the approximate optimal supply intensity is got in three cases.