Please use this identifier to cite or link to this item: https://ah.nccu.edu.tw/handle/140.119/46079


Title: Using VSI EWMA charts to monitor dependent process steps with incorrect adjustment
Authors: 楊素芬
Yang,Su-Fen;Yu,Yi-Ning
Keywords: Control charts;Dependent process steps;Incorrect adjustment;Markov chain
Date: 2009.01
Issue Date: 2010-10-06 11:21:08 (UTC+8)
Abstract: The article considers the variable process control scheme for two dependent process steps with incorrect adjustment. Incorrect adjustment
of a process may result in shifts in process mean, ultimately affecting the quality of products. We construct variable sampling interval
(VSI) EWMAZX and EWMAZe control charts to effectively monitor the quality variable produced by the first process step with
incorrect adjustment and the quality variable produced by the second process step with incorrect adjustment. The performance of the
proposed VSI control charts is measured by the adjusted average time to signal (AATS) derived using a Markov chain approach. An
example of the automobile braking system with incorrect adjustment shows the application and performance of the proposed VSI
EWMAZX and EWMAZe control charts in detecting shifts in process mean. Furthermore, the performance of the proposed VSI
EWMAZX and EWMAZe control charts and the fixed sampling interval (FSI) EWMAZX and EWMAZe control charts are compared
by numerical analysis results. These demonstrate that the former is much faster in detecting small and median shifts in mean. The optimum
VSI EWMAZX and EWMAZe control charts are also proposed using optimization technique to minimize AATS when quality engineers
cannot specify the values of variable sampling intervals. It has been found that the optimum VSI EWMAZX and EWMAZe control
charts always work better than the VSI EWMAZX and EWMAZe control charts.
Relation: Expert System and Application,36(1),442-454
Data Type: article
DOI 連結: http://dx.doi.org/10.1016/j.eswa.2007.09.036
Appears in Collections:[統計學系] 期刊論文

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