A production–inventory model incorporating the effect of preservation technology investment when demand is fluctuating with time

In most of the inventory models in the literature, the rate of deterioration of goods is viewed as an exogenous variable, which is not subject to control. In the real market, firms can reduce the rate of deterioration of products by means of effective capital investment in preservation technology. In this research, we formulate a production–inventory model for deteriorating items with time-varying demand and finite replenishment rate by allowing preservation technology cost as a decision variable in conjunction with production policy. The objective is to find the optimal production and preservation technology investment strategies while minimizing the total cost over the planning horizon. A traditional particle swarm optimization is coded and used to solve the mixed-integer nonlinear programming problem. Some numerical examples are used to illustrate the features of the proposed model.