Abstract:
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Industrial process quality control frequently uses the Exponential Weighted Moving Average control chart (EWMA CC) and the double EWMA CC (DEWMA CC) to detect small shifts in a process when the sample size . The EWMA CC was initially developed and evaluated in 1992. In 2005, the EWMA technique was extended to the DEWMA. Research into DEWMA has been developed and assessed several alternatives, including multivariate control charts. These studies are focused on detecting small shifts in process. In practice, however, sometimes it is wished to detect small trends instead of shifts in the process. The effectiveness of these methods to determine small trends in a process has not been thoroughly researched. This research reviews a new control chart called "The Double Exponential Weighted Moving Average based on a Linear Prediction" (DEWMALP) and compares its performance and efficiency with the performance of others control charts including EWMA CC, DEWMA CC, Shewhart CC, the General Ratio Likelihood (GRL) control chart for drift, and the Fahmy and Elsayed Chi-squared control chart. The conclusions about these differences are presented and implications are discussed.
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