Lot sizing models for deteriorating items with time-dependent demand

This paper presents a general Formulation of the inventory lot-sizing problem with deteriorating items and continuous time-dependent demand. Three distributions of the time to deterioration are analysed as special cases. These are the Erlang, uniform, and exponential distributions. For the case of constant deterioration, an efficient iterative procedure is developed to provide the optimal replenishment schecule. Numerical examples are included to illustrate the general formulation and the proposed solution procedure. The results of these examples indicate that similar replenishment schedules are obtained for the three distributions with equal expected value.