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Variable sampling interval exponentially weighted moving average median chart with estimated process parameters

  • Michael B.C. Khoo
  • , Sajal Saha
  • , How Chinh Lee
  • , Philippe Castagliola

Research output: Contribution to journalArticleResearchpeer-review

Abstract

The variable sampling interval exponentially weighted moving average median chart with estimated process parameters is proposed. The charting statistic, optimal design, performance evaluation, and implementation of the proposed chart are discussed. The average of the average time to signal (AATS) criterion is adopted to evaluate the performance of the proposed chart. The estimated process parameter-based VSI EWMA median (VSI EWMA median-e) chart is compared with the estimated process parameter-based Shewhart median (SH median-e), EWMA median (EWMA median-e), and variable sampling interval run sum median (VSI RS median-e) charts, in terms of the AATS criterion, where the VSI EWMA median-e chart is shown to be superior. When process parameters are estimated, the standard deviation of the average time to signal (SDATS) criterion is used to evaluate the AATS performance of the VSI EWMA median-e chart. Based on the SDATS criterion, the minimum number of phase-I samples required by the VSI EWMA median-e chart so that its performance is close to the known process parameters VSI EWMA median chart is recommended.

Original languageEnglish
Pages (from-to)2732-2748
Number of pages17
JournalQuality and Reliability Engineering International
Volume35
Issue number8
DOIs
Publication statusPublished - Dec 2019
Externally publishedYes

Keywords

  • average of the average time to signal (AATS)
  • average time to signal (ATS)
  • estimated process parameters
  • standard deviation of the average time to signal (SDATS)

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