• Title/Summary/Keyword: CV-CUSUM control chart

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Statistical Design of CV-CUSUM Control Chart Using Fast Initial Response (FIR을 이용한 CV-CUSUM 관리도의 통계적 설계)

  • Lee, Jung-Hoon;Kang, Hae-Woon;Hong, Eui-Pyo;Kang, Chang-Wook
    • Journal of Korean Society for Quality Management
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    • v.38 no.3
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    • pp.313-321
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    • 2010
  • The coefficient of variation represents the ratio of the standard deviation to the mean, and it is a useful statistic for comparing the degree of variation from one data series to another, even if the means are drastically different from each other. Recently, the CV control chart is developed for monitoring processes in such situations. However, the CV control chart has low performance in detecting small shift. Due to the development of equipment and technique, currently, small shift of process occurs more frequently than large shift. In this paper, we proposes the CV-CUSUM control chart using CUSUM scheme which is cumulative sum of the deviations between each data point and a target value to detect a small shift in the process. We also found that the FIR(fast initial response) CUSUM control chart is especially valuable at start-up or after a CV-CUSUM control chart has signaled out-of-control.