A survey of maintenance policies of deteriorating systems

Applied Probability and Queues.

An Introduction to Probability Theory and its Applications, Volume I

(1966). Mathematical Theory of Reliability. Journal of the Operational Research Society: Vol. 17, No. 2, pp. 213-215.

https://link.springer.com/content/pdf/10.1057%2Fjors.1966.43.pdf

Mathematical Theory of Reliability

Multiple-supplier inventory models in supply chain management: A review

A spare parts stocking policy based on equipment criticality

Whenever demand for a single item can be categorised into classes of different priority, an inventory rationing policy should be considered. In this paper we analyse a continuous review (s, Q) model with lost sales and two demand classes. A so-called critical level policy is applied to ration the inventory among the two demand classes. With this policy, low-priority demand is rejected in anticipation of future high-priority demand whenever the inventory level is at or below a prespecified critical level. For Poisson demand and deterministic lead times, we present an exact formulation of the average inventory cost. A simple optimisation procedure is presented, and in a numerical study we compare the optimal rationing policy with a policy where no distinction between the demand classes is made. The benefit of the rationing policy is investigated for various cases and the results show that significant cost reductions can be obtained.

https://link.springer.com/content/pdf/10.1057%2Fpalgrave.jors.2600844.pdf

Inventory rationing in an (s, Q) inventory model with lost sales and two demand classes

In this paper an inventory model with several demand classes, prioritised according to importance, is analysed. We consider a lot-for-lot or (S - 1, S) inventory model with lost sales. For each demand class there is a critical stock level at and below which demand from that class is not satisfied from stock on hand. In this way stock is retained to meet demand from higher priority demand classes. A set of such critical levels determines the stocking policy. For Poisson demand and a generally distributed lead time, we derive expressions for the service levels for each demand class and the average total cost per unit time. Efficient solution methods for obtaining optimal policies, with and without service level constraints, are presented. Numerical experiments in which the solution methods are tested demonstrate that significant cost reductions can be achieved by distinguishing between demand classes.

/pdf/on-the-s-1-s-lost-sales-inventory-model-with-priority-demand-3e313uat0n.pdf

On the (S-1, S) lost sales inventory model with priority demand classes

In this chapter we discuss inventory systems where several demand classes may be distinguished. In particular, we focus on single-location inventory systems and we analyse the use of a so-called critical level policy. With this policy some inventory is reserved for high-priority demand. A number of practical examples where several demand classes naturally arise are presented, and the implications and modelling of the critical level policy in distribution systems are discussed. Finally, an overview of the literature on inventory systems with several demand classes is given.

/pdf/an-overview-of-inventory-systems-with-several-demand-classes-xequ23wylq.pdf

Marcel Kleijn

Papers

A spare parts stocking policy based on equipment criticality

Inventory rationing in an (s, Q) inventory model with lost sales and two demand classes

On the (S-1, S) lost sales inventory model with priority demand classes

An Overview of Inventory Systems with Several Demand Classes

An overview of inventory systems with several demand classes