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Monitoring Process Variability Using EWMA
2006During the last decade, the use of the exponentially weighted moving average (EWMA) statistic as a process-monitoring tool has become more and more popular in the statistical process-control field. If the properties and design strategies of the EWMA control chart for the mean have been thoroughly investigated, the use of the EWMA as a tool for ...
CASTAGLIOLA P +2 more
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The EWMA Patient Outcome Group
Journal of Wound Care, 2009Across Europe, clinical experts in wound care and industry representatives have joined forces to propose recommendations for clinical data collection on chronic wound management. Here, the chair of the group, Finn Gottrup, outlines its main objectives
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An adaptive multivariate EWMA chart
Computers & Industrial Engineering, 2019Abstract The adaptive multivariate EWMA (AMEWMA) and adaptive multivariate CUSUM (AMCUSUM) charts are recently proposed as they provide an overall good detection over a range of mean shift sizes than their non-adaptive conventional counterparts. In this paper, we propose an adaptive MEWMA (AMEWMA) chart for monitoring the infrequent changes in the ...
Abdul Haq, Michael B.C. Khoo
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Optimal hierarchical EWMA forecasting
International Journal of ForecastingPrediction of demand at different levels of aggregation is a crucial task in many business and industrial activities. This task may be extremely challenging when the number of time series increases together with the number of parameters governing the dynamics of the underlying model. This paper proposes theoretical and empirical contributions providing
Giacomo Sbrana, Matteo Pelagatti
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Quality Technology & Quantitative Management, 2005
AbstractIn this paper, we extend the exponentially weighted moving average (EWMA) technique to double exponentially weighted moving average (DEWMA) technique. We show that DEWMA mean charts perform better than EWMA mean charts in detecting small mean shifts ranging from 0.1 to 0.5 of the process standard deviation, and that the two types of charts ...
Lingyun Zhang, Gemai Chen
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AbstractIn this paper, we extend the exponentially weighted moving average (EWMA) technique to double exponentially weighted moving average (DEWMA) technique. We show that DEWMA mean charts perform better than EWMA mean charts in detecting small mean shifts ranging from 0.1 to 0.5 of the process standard deviation, and that the two types of charts ...
Lingyun Zhang, Gemai Chen
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Improved variable EWMA controller design
Proceeding of the 11th World Congress on Intelligent Control and Automation, 2014The exponentially weighted moving average (EWMA) controller is a popular run-to-run (RtR) control scheme in semiconductor manufacturing because of its effectiveness and simplicity. In this paper we propose an improved variable EWMA controller design method.
Ming-Da Ma, Jia-Yi Li, Kai Zhang
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Estimating Value at Risk: From JP Morgan's Standard-EWMA to Skewed-EWMA Forecasting
SSRN Electronic Journal, 2007Driven significantly by JP Morgan's RiskMetrics system with exponentially weighted moving average (EWMA) forecasting, value-at-risk (VaR) has become a popularly used measurement of the extent to which a financial asset is subject to the risks present in financial markets.
Zudi LU, Hai Huang
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The MaxMin EWMA tolerance limits
International Journal of Quality & Reliability Management, 2000When there is a change in a process, the MaxMin exponentially weighted moving average (EWMA) control chart shows which parameters have increased or decreased. The MaxMin EWMA may also be viewed as smoothed tolerance limits. Tolerance limits are limits that include a specific proportion of the population at a given confidence level.
Raid W. Amin, Kuiyuan Li
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2002
A problem with the conventional Shewhart charts is that the decisions are usually based on single observations. Such decision implies a high probability of false alarms. Also, small shifts in the process characteristics, which are of increasing importance from the point of view of efforts for continuous quality improvement, cannot be detected easily ...
M. Xie, T. N. Goh, V. Kuralmani
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A problem with the conventional Shewhart charts is that the decisions are usually based on single observations. Such decision implies a high probability of false alarms. Also, small shifts in the process characteristics, which are of increasing importance from the point of view of efforts for continuous quality improvement, cannot be detected easily ...
M. Xie, T. N. Goh, V. Kuralmani
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The EWMA median chart with estimated parameters
IIE Transactions, 2015ABSTRACTThe usual practice in control charts is to assume that the chart parameters are known or can be accurately estimated from in-control historical samples and the data are free from outliers. Both of these assumptions are not realistic in practice: a control chart may involve the estimation of process parameters from a very limited number of ...
Castagliola, Philippe +2 more
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