The failure rate dynamics in heterogeneous populations

Ji Hwan Cha, Maxim Finkelstein

Research output: Contribution to journalArticlepeer-review

18 Scopus citations

Abstract

Most populations encountered in real world are heterogeneous. In reliability applications, the mixture (observed) failure rate, obviously, can be considered as a measure of 'average' quality in these populations. However, in addition to this average measure, some variability characteristics for failure rates can be very helpful in describing the time-dependent changes in quality of heterogeneous populations. In this paper, we discuss variance and the coefficient of variation of the corresponding random failure rate as variability measures for items in heterogeneous populations. Furthermore, there is often a risk that items of poor quality are selected for important missions. Therefore, along with the 'average quality' of a population, more 'conservative' quality measures should be also defined and studied. For this purpose, we propose the percentile and the tail-mixture of the failure rates as the corresponding conservative measures. Some illustrative examples are given.

Original languageEnglish
Pages (from-to)120-128
Number of pages9
JournalReliability Engineering and System Safety
Volume112
DOIs
StatePublished - 2013

Keywords

  • Coefficient of variation
  • Heterogeneous population
  • Quality measures
  • Stochastically ordered subpopulations
  • Variance

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