Percentiles of the run-length distribution of the Exponentially Weighted Moving Average (EWMA) median chart

K. L. Tan, Zhi Lin Chong, Michael B. C. Khoo, Wei Lin Teoh, Sin Yin Teh

Research output: Contribution to journalArticle

28 Downloads (Pure)

Abstract

Quality control is crucial in a wide variety of fields, as it can help to satisfy customers' needs and requirements by enhancing and improving the products and services to a superior quality level. The EWMA median chart was proposed as a useful alternative to the EWMA X chart because the median-type chart is robust against contamination, outliers or small deviation from the normality assumption compared to the traditional X-type chart. To provide a complete understanding of the run-length distribution, the percentiles of the run-length distribution should be investigated rather than depending solely on the average run length (ARL) performance measure. This is because interpretation depending on the ARL alone can be misleading, as the process mean shifts change according to the skewness and shape of the runlength distribution, varying from almost symmetric when the magnitude of the mean shift is large, to highly right-skewed when the process is in-control (IC) or slightly out-of-control (OOC). Before computing the percentiles of the run-length distribution, optimal parameters of the EWMA median chart will be obtained by minimizing the OOCARL, while retaining the ICARL at a desired value.

Original languageEnglish
Article number012156
JournalJournal of Physics: Conference Series
Volume890
DOIs
Publication statusPublished - 21 Sep 2017

ASJC Scopus subject areas

  • Physics and Astronomy(all)

Fingerprint Dive into the research topics of 'Percentiles of the run-length distribution of the Exponentially Weighted Moving Average (EWMA) median chart'. Together they form a unique fingerprint.

  • Cite this