We consider a single warehouse where spare parts of multiple stock-keeping units are kept on stock to serve customers with (close-to-)identical machines. Customers are divided into multiple customer classes, and a target aggregate fill rate is set per class. In order to get differentiated service levels, critical level policies are assumed. We formulate a multi-item, single-stage spare parts in...

In this research, a new method is proposed for the optimization of warship spare parts stock with genetic algorithm. Warships should fulfill her duties in all circumstances. Considering the warships have more than a hundred thousand unique parts, it is a very hard problem to decide which spare parts should be stocked at warehouse aiming to use in case of failure. In this study, genetic algorith...

This document was submitted as a dissertation in August 2003 in partial fulfillment of the requirements of the doctoral degree in public policy analysis at the RAND Graduate School. The faculty committee that supervised and approved the dissertation consisted of The RAND Graduate School dissertation series reproduces dissertations that have been approved by the student's dissertation committee....

In airline industries, the aircraft maintenance cost takes up about 13% of the total operating cost. It can be reduced by a good planning. Spare parts inventories exist to serve the maintenance planning. Compared with commonly used reorder point system (ROP) and forecasting methods which only consider historical data, this paper presents two non-linear programming models which predict impending...

We present a problem on risk pooling and cost allocation in inventory of spare parts motivated in the oil and gas sector. Spare parts are held to facilitate operational conditions. Multiple inventory plants control their stock per separate. In practice, however, they supply each other when needed. Risk pooling is a source of savings in this situation. Under a centralized inventory solution, the...

In many industrial sectors, firms are dealing with a demand which is more and more uncertain often due to the supply chain structure. One of the most critical effects of demand uncertainty is the simultaneous increase of inventories and decrease of customer service. This work describes an integrated system for managing inventories in a multi-echelon spare parts supply chain, in which 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...

If necessity is the mother of invention, then its father is an inveterate tinkerer, with a large garage full of spare parts. Innovation (like homicide) requires motive and opportunity. Clearly, the predominant ‘motive’ during the evolution of a novel gene function is to gain a selective advantage. To understand why gene duplications represent the major ‘opportunities’ from which new genes evolv...

The aim of this paper is to propose and discuss a hierarchical multi-criteria spare parts classification method developed for inventory management purposes and tested through an intensive case study in an Italian household appliances manufacturing company. In particular, the classification scheme under concern is built on the basis of several key dimensions in an almost hierarchical fashion, re...