Citation

Ng, Peh Sang and Chong, Zhi Lin and Lim, Huai Tein and Yeong, Wai Chung and Song, Poh Choo (2025) An Enhanced EWMA Chart with Variable Sampling Interval based on Expected Average Time to Signal. In: 7th IEEE International Conference on Artificial Intelligence in Engineering and Technology, IICAIET 2025, 26 August 2025 - 28 August 2025, Kota Kinabalu, Malaysia.

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Abstract

The auxiliary information based variable sampling interval Exponentially Weighted Moving Average (VSI EWMA AI) chart, which combines the EWMA AI chart with the variable sampling interval (VSI) scheme has been shown to outperform the EWMA AI chart in detecting the mean shifts. However, the performance on the VSI EWMA AI chart was investigated by assuming the exact shift size is known in advance. Practically, this assumption is often unrealistic because the exact shift size is usually unknown. If the actual shift size deviates from the one assumed during the design of the control chart, the chart’s run length properties could be significantly affected, making the interpretation on the chart’s performance inaccurate. To address this limitation, the expected average time to signal (EATS) performance metric which accounts for shift sizes within a specified interval is adopted, that is, the optimal design of the VSI EWMA AI chart in minimizing the out-of-control EATS is proposed. The results generally demonstrate the superiority of the proposed VSI EWMA AI chart over the EWMA AI chart for the shift interval (0.2, 0.6) across different values of the correlation coefficient between the study and auxiliary variables (ρ), and for the shift interval (0.5, 1.0) when ρ is small to moderate.

Item Type:	Conference or Workshop Item (Paper)
Uncontrolled Keywords:	Control chart, expected average time to signal
Subjects:	Q Science > QA Mathematics > QA71-90 Instruments and machines
Divisions:	Faculty of Computing and Informatics (FCI)
Depositing User:	Ms Rosnani Abd Wahab
Date Deposited:	17 Mar 2026 06:52
Last Modified:	17 Mar 2026 06:52
URII:	http://shdl.mmu.edu.my/id/eprint/15498

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