Journal ArticleDOI
A Johnson's type transformation EWMA-S² control chart
TLDR
In this article, the computation of both the control limits and the parameters of the Johnson SB transformation of the EWMA-J-S² chart are explained and the distributional properties of the transformed sample variance are derived.Abstract:
This article demonstrates how a four parameters (bounded) Johnson SB transformation combined with an EWMA approach can be used to monitor the sample variance of a process. The resulting chart will be called an EWMA-J-S² chart. In this article, the computation of both the control limits and the parameters of the Johnson SB transformation of the EWMA-J-S² chart are explained. An easy-to-use table providing useful constants and an illustrative example are given. The distributional properties of the transformed sample variance are derived and, finally, an optimal design strategy based on the ARL is presented and a list of optimal design parameters for the EWMA-J-S² chart is provided.read more
Citations
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Journal ArticleDOI
CS-EWMA Chart for Monitoring Process Dispersion
TL;DR: A new memory-type control chart based on the same transformation, named as CS-EWMA chart, is proposed for monitoring the process dispersion by mixing the effects of EWMA and CUSUM charts.
Journal ArticleDOI
Alternative methods for the simultaneous monitoring of simple linear profile parameters
TL;DR: New methods are designed for the simultaneous monitoring of simple linear profile parameters, which requires single charting constant and have several advantages such as simplicity, efficiency, and ease of applicability.
Journal ArticleDOI
Memory-Type Control Charts for Monitoring the Process Dispersion
TL;DR: The proposed charts are found to be better in detecting both positive as well as negative shifts and to have slightly smaller ARLs for larger shifts, while for smaller shifts, the floating TS 2 chart has better performance.