Title
One-sided control charts for monitoring the multivariate coefficient of variation in short production runs
Abstract
In production, it is common to deal with short production runs, where flexibility is required in the built-up of parts to produce numerous variants of manufactured goods. Monitoring the multivariate coefficient of variation (MCV) is an effective method to monitor the relative multivariate variability compared with the mean. Monitoring the relative multivariate variability is important when practitioners are not interested in the changes in the mean vector or the covariance matrix. Monitoring the univariate coefficient of variation in short production runs has already been successfully executed. In this paper, the statistical performance of one-sided charts for monitoring the MCV of a multivariate process with finite horizon is investigated. Prior to this work, no attempt has been made to study process monitoring of MCV in short production runs. Investigations are made when the exact shift size can be specified and when there is a random shift size. It is found that the proposed upward chart detects an increasing shift in the MCV quicker than its downward counterpart detects a decreasing shift, for the same shift size (from the nominal value). An example is presented to illustrate the implementation of the new method.
Year
DOI
Venue
2019
10.1177/0142331218789481
TRANSACTIONS OF THE INSTITUTE OF MEASUREMENT AND CONTROL
Keywords
DocType
Volume
Expected truncated average run length,multivariate coefficient of variation,short production runs,statistical process control,truncated average run length
Journal
41
Issue
ISSN
Citations 
SP6
0142-3312
0
PageRank 
References 
Authors
0.34
16
4
Name
Order
Citations
PageRank
Mahfuza Khatun110.72
Michael B. C. Khoo228249.97
Ming Ha Lee3429.62
Philippe Castagliola452961.65