The practical experiences reveal that the inflation is non-deterministic and variable. Therefore, a mathematical model for the optimal production for an inventory control system of deteriorating items is formulated under time-varying and stochastic inflation environment. The demand rate is a function of inflation and the time horizon is finite. In the real situation, some but not all customers ...

We study an inventory system that consists of two demand classes. The orders in the first class need to be satisfied immediately, whereas the orders in the second class are to be filled in a given demand lead–time. The two classes are also of different criticality. For this system, we propose a policy that rations the non–critical orders. Under a one-for-one replenishment policy with backorderi...

In this paper, a realistic replenishment model with multiple warehouses (one is primary warehouse (PW) from where the items are sold and others are secondary warehouses (SWs) where the items are stored) is developed with fuzzy lead-time under the assumption that the capacities of the warehouses are finite. Inflation and time value of money are taken into account. The items of secondary warehous...

Nowadays, Companies have to deal with an uncertain demand which is more difficult to handle when it has a non-stationary pattern. Simultaneous decrease of customer service and increase of stock costs are the most significant effects of such demand uncertainty. To deal with this issue, inventory optimization models must be adapted to cover a multi-echelon network structure and to consider altern...

Reverse logistics activities have received increasing attention within logistics and operations management during the last years, both from a theoretical and a practical point of view. The field of reverse logistics includes all logistics processes starting with the take-back of used products from customers up to the stage of making them reusable products or disposing them. In this paper, a sin...

We study static repair priorities in a system consisting of one repair shop and one stockpoint, where spare parts of multiple repairables are kept on stock to serve an installed base of technical systems. Demands for ready-for-use parts occur according to Poisson processes, and are accompanied by returns of failed parts. The demands are met from stock if possible, and otherwise they are backord...

The processing time of large orders is, in many industries, longer than that of small orders. This renders supply lead times in such settings to be increasing in the order size. Yet that pattern is not re#ected in existing inventory control models, especially those allowing for random lead times. This work aims at rectifying the situation. Our setting is an order-quantity/reorder-pointmodel wit...

it is assumed in most of the existing models that the items can be stored for an unlimited time to meet the future’s demand and their quality and quantity does not change during that period. nevertheless there are special kinds of products which deteriorate or become unusable (such as food products, alcohol, medicines, etc.). therefore if the rate of deterioration is significantly high, the imp...

The recent advances in manufacturing systems motivate several studies to focus on Economic Production Quantity (EPQ) problem. Althuogh there are several extentions to the EPQ, this paper provides a new extension by considering some of the real world parameters like: (a) shortages in the form of partial backordering, (b) inventory can deteriorate stochastically, (c) machine can break down stocha...