Combined synthetic and |S| chart for monitoring process dispersion |
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| Authors: | Ming Ha Lee Michael B C Khoo |
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| Institution: | 1. Faculty of Engineering, Computing and Science, Swinburne University of Technology Sarawak Campus, Kuching, Sarawak, Malaysia;2. School of Mathematical Sciences, Universiti Sains Malaysia, Penang, Malaysia |
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| Abstract: | This article proposes a multivariate control chart, the syn-|S| chart, which comprises a standard |S| subchart and a multivariate synthetic sample generalized variance |S| (synthetic |S|) subchart, for detecting shifts in the covariance matrix of a multivariate normally distributed process. A procedure for the optimal design of the syn-|S| chart by minimizing the average extra quadratic loss is provided. The syn-|S| chart has better overall performance compared to the synthetic |S| chart and the standard |S| chart, based on the zero-state and steady-state modes. An example is given to illustrate the operation of the synthetic |S| chart. |
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| Keywords: | Average run length Multivariate chart Sample generalized variance Synthetic chart |
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