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On allocation of spares at component level versus system level

Part of: Survival analysis and censored data Operations research and management science

Published online by Cambridge University Press:  14 July 2016

Harshinder Singh  and
R. S. Singh
Harshinder Singh*
Affiliation:
Panjab University
R. S. Singh*
Affiliation:
University of Guelph
*
∗Postal address: Department of Statistics, Panjab University, Chandigarh 160014, India.
∗∗Postal address: Department of Mathematics and Statistics, University of Guelph, Guelph, Ontario, Canada N1G 2W1.
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Abstract

Design engineers are well aware that a system where active spare allocation is made at the component level has a lifetime stochastically larger than the corresponding system where active spare allocation is made at the system level. In view of the importance of hazard rate ordering in reliability and survival analysis, Boland and El-Neweihi (1995) recently investigated this principle in hazard rate ordering and demonstrated that it does not hold in general. They showed that for a 2-out-of-n system with independent and identical components and spares, active spare allocation at the component level is superior to active spare allocation at the system level. They conjectured that such a principle holds in general for a k-out-of-n system when components and spares are independent and identical. We prove that for a k-out-of-n system where components and spares have independent and identical life distributions active spare allocation at the component level is superior to active spare allocation at the system level in likelihood ratio ordering. This is stronger than hazard rate ordering, thus establishing the conjecture of Boland and El-Neweihi (1995).

Keywords

ACTIVE SPARE ALLOCATIONHAZARD RATE ORDERINGORDER STATISTICSLIKELIHOOD RATIO ORDERING

MSC classification

Primary: 62N05: Reliability and life testing
Secondary: 90B25: Reliability, availability, maintenance, inspection
Type
Short Communications
Information
Journal of Applied Probability , Volume 34 , Issue 1 , March 1997 , pp. 283 - 287
Copyright
Copyright © Applied Probability Trust 1997 

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