A new demerit control chart for monitoring the quality of multivariate Poisson processes

ABSTRACT

This study aims to develop a new demerit control chart suitable for monitoring the quality of manufacturing processes with multiple characteristics subject to multivariate weighted Poisson distribution. Considering the correlation among different quality characteristics and their degrees of influence on the final product, we propose a new statistic for demerit scheme which gives different weights to different quality characteristics. Then, a new demerit control chart for multivariate weighted Poisson distribution (WMP chart) is developed accordingly. Moreover, a simulation study is conducted to evaluate the detecting performances of our proposed WMP chart and multivariate Poisson control chart (MP chart) using the out-of-control average run length (ARL${}_1$) Finally, a numerical example with a two dimensional telecommunication data set is given to demonstrate the usefulness of our proposed WMP chart. Both the simulation results and numerical example show that the detecting ability of our proposed WMP chart outperforms that of the MP chart when a process shift occurs. Hopefully, the results of this research can provide a better alternative for detecting the mean shifts occurred in a multivariate Poisson processes.

KEYWORDS:

• Demerit control chart
• average run length
• multivariate Poisson control chart
• multiple quality characteristics
• multivariate weighted Poisson distribution

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The second author would like to gratefully acknowledge financial support (MOST 107-2410-H-006-035) from the Ministry of Science and Technology of Taiwan, ROC.