Author
Tse-Chieh Lin
Bio: Tse-Chieh Lin is an academic researcher from National Taiwan University of Science and Technology. The author has contributed to research in topics: Control limits & X-bar chart. The author has an hindex of 1, co-authored 1 publications receiving 132 citations.
Topics: Control limits, X-bar chart, Control chart, EWMA chart
Papers
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TL;DR: In this paper, a generalized control chart called the generally weighted moving average (GWMA) control chart was proposed and analyzed for detecting small shifts in the mean of a process, with time varying control limits to detect start-up shifts more sensitively.
Abstract: A generalization of the exponentially weighted moving average (EWMA) control chart is proposed and analyzed. The generalized control chart we have proposed is called the generally weighted moving average (GWMA) control chart. The GWMA control chart, with time‐varying control limits to detect start‐up shifts more sensitively, performs better in detecting small shifts of the process mean. We use simulation to evaluate the average run length (ARL) properties of the EWMA control chart and GWMA control chart. An extensive comparison reveals that the GWMA control chart is more sensitive than the EWMA control chart for detecting small shifts in the mean of a process. To enhance the detection ability of the GWMA control chart, we submit the composite Shewhart‐GWMA scheme to monitor process mean. The composite Shewhart‐GWMA control chart with/without runs rules is more sensitive than the GWMA control chart in detecting small shifts of the process mean. The resulting ARLs obtained by the GWMA control chart...
148 citations
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TL;DR: Both univariate and multivariate nonparametric control charts are reviewed, unlike the past reviews, which did not include the multivariate charts, here they are reviewed.
Abstract: Control charts that are based on assumption(s) of a specific form for the underlying process distribution are referred to as parametric control charts. There are many applications where the...
106 citations
TL;DR: A comprehensive review of the literature on the industrial applications of performance assessment, as well as some of the currently available software, is also presented in this paper, with a focus on supervisory control.
Abstract: In many industrial plants, multiple, interconnected control loops are common. Their maintenance and improvement requires detailed controller performance assessment to determine not only whether they are behaving well, but also to determine the potential cause of any observed problems. Techniques for performance assessment can be divided into two broad categories (1) performance assessment of regulatory control loops; and (2) performance assessment of supervisory control loops that evaluate the economic performance of advanced control strategies, such as model predictive control (MPC). A comprehensive review of the literature on the industrial applications of performance assessment, as well as some of the currently available software, is also presented. © 2011 Canadian Society for Chemical Engineering
68 citations
TL;DR: The results of this study indicated that using 10,000 replications was unnecessarily large and a smaller number of replications could be used to reproduce the target ARLs within the 2% error bands satisfying the modified Mundfrom's criteria.
Abstract: Monte Carlo simulations have been used extensively in studying the performance of control charts. Researchers have used various numbers of replications in their studies, but almost none of them provided justifications for the number of replications used. Currently, there are no empirically based recommendations regarding the required number of replications to ensure accurate results. This research examined six recently published studies to develop recommendations for the minimum number of replications necessary to reproduce the reported results within a specified degree of accuracy. The results of this study indicated that using 10,000 replications was unnecessarily large and a smaller number of replications could be used to reproduce the target ARLs within the 2% error bands satisfying the modified Mundfrom's criteria. In many cases, only 5,000 replications or fewer were required. In general, the number of replications required to reproduce the target ARL decreased as the shift size increased. In additio...
68 citations
TL;DR: In this paper, the nonparametric generally weighted moving average sign chart is developed to improve the detection capability in small process shifts and can compete with theNonparametric exponentially weighted movingAverage sign chart.
Abstract: Traditional control charts are established on the assumption that the observations of a process follow a normal or specific probability distribution. However, in many applications, there is insufficient information to justify this assumption. Thus, nonparametric control charts have been proposed in recent years and hold a significant place among statistical process control charts. Some of these charts are designed to monitor the location parameter, whereas others are available for the scale. The major advantage of these control charts is that the underlying process does not specifically assume normality or other specific distributions. In this paper, the nonparametric generally weighted moving average sign chart is developed to improve the detection capability in small process shifts. Simulation studies show that the nonparametric generally weighted moving average sign chart is not optimal in all scenarios but can compete with the nonparametric exponentially weighted moving average sign chart. Copyright © 2014 John Wiley & Sons, Ltd.
62 citations
TL;DR: The performance of the proposed progressive mean (PM) controlchart is compared to comparedones for small and moderates shifts, and its performance for large shifts is better (in terms of the average run length).
Abstract: Control charts are widely used for process monitoring They show whether the variation is due to common causes or whethersome of the variation is due to special causes To detect large shifts in the process, Shewhart-type control charts are preferredCumulativesum(CUSUM)andexponentiallyweightedmovingaverage(EWMA)controlchartsaregenerallyusedtodetectsmalland moderate shifts Shewhart-type control charts (without additional tests) use only current information to detect specialcauses, whereas CUSUM and EWMA control charts also use past information In this article, we proposed a control chart calledprogressivemean(PM)controlchart,inwhichaPMisusedasaplottingstatisticTheproposedchartisdesignedsuchthatitusesnot only the current information but also the past information Therefore, the proposed chart is a natural competitor for theclassical CUSUM, the classical EWMA and some recent modifications of these two charts The conclusion of this article is thatthe performanceofthe proposedPMchart issuperiortothe comparedonesfor small and moderateshifts, and its performancefor large shifts is better (in terms of the average run length) Copyright © 2012 John Wiley & Sons, LtdKeywords: average run length (ARL); memory control charts; EWMA; CUSUM; progressive mean (PM); statistical process control
61 citations