New modified exponentially weighted moving average-moving average control chart for process monitoring

Abstract

The mixed control chart is proposed to improve detection performance with fewer process shifts. In this study, we proposed the modified exponentially weighted moving average - moving average control chart (MMEM), a new mixed control chart for observing the changes in the process mean. Average run length, standard deviation of run length, and median run length can be used to examine the effectiveness of detecting changes in the proposed chart with Shewhart, Moving Average (MA), Modified Exponentially Weighted Moving Average (MEWMA), and Mixed Moving Average - Modified Exponentially Weighted Moving Average (MMME) control charts in parametric and nonparametric distributions that use Monte Carlo simulation. The results demonstrate that the proposed chart outperforms other control charts mostly in the detection of small-to-moderate shifts. To illustrate the application of the proposed chart, chemical process temperature data and dataset on survival times of a group of patients suffering from head and neck cancer disease and treated with radiotherapy were provided, and it was discovered that the proposed chart performs better than other control charts.

KEYWORDS:

• Mixed control chart
• modified exponentially weighted moving average- moving average control chart
• average run length
• modified exponentially weighted moving average control chart
• moving average control chart

Acknowledgements

The authors would like to thank the Ministry of Science and Technology Thailand for the Ph.D. scholarship. The authors would like to express their appreciation to Graduate College, King Mongkut's University of Technology North Bangkok and Rajamangala University of Technology Lanna for their all support. Besides, we would like to express our gratitude to Thailand Science Research and Innovation, Ministry of Higher Education, Science, Research for supporting the research fund with Contract no. KMUTNB-FF-65-41.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by Thailand Science Research and Innovation, Ministry of Higher Education, Science, Research.: [Grant Number KMUTNB-FF-65-41].