Purpose – The exponentially weighted moving average (EWMA) control charts are widely used in industries for monitoring small and moderate process shifts. The purpose of this paper is to develop an algorithm for the optimization design of the EWMA chart (known as MD‐EWMA chart)....

States that, under certain circumstances, a single • control chart with tightened control limits may be more effective for detecting process shifts than the combination of • and s control charts, while the type I error can be kept at the same level. A computer program is developed to decide...

The mean shifts (or range shifts, standard deviation shifts) of a process may be classified into a set of modes (or classifications), each of which is characterized by the shift magnitude (δ) and the occurrence probability, f. The knowledge relating to the shift modes is useful to the...

Studies the necessity of controlling the variation of the skewness of the process distribution in order to reduce the product scrap. Proposes a γ control chart for detecting the skewness shift, also implements a simulation procedure to decide the control limits of the γ chart.

Explains that the shifts of a process may be classified into a set of modes (or classifications), each of which is incurred by an assignable cause. Presents an algorithm to determine the process shift mode and estimate the run length when an out‐of‐control status is signalled by the x ‐ or...

Presents an approach to determine the optimum control limits of the x ‐bar chart for skewed process distributions. The approach takes both the control limits of the x ‐bar chart and the specification limits of x into consideration, and relates the out‐of‐control status directly with the...