Journal ArticleDOI
A Nonparametric Phase I Control Chart for Monitoring the Process Variability with Individual Observations Based on Empirical Likelihood Ratio
Wei-Heng Huang,Arthur B. Yeh +1 more
TLDR
This work proposes a new nonparametric Phase I control chart for monitoring the scale parameter based on the empirical likelihood ratio test and shows that the proposed chart is more effective than the existing charts in terms of signal probability.Abstract:
Among the statistical process control (SPC) techniques, the control chart has been proven to be effective in process monitoring. The Shewhart chart is one of the most commonly used control charts for monitoring the process mean and variability based on the assumption that the distribution of the quality characteristic is normal. However, in practice, many quality characteristics are not normally distributed. Most of the existing nonparametric control charts are designed for Phase II monitoring. Little has been done in developing the nonparametric Phase I control charts especially for individual observations. In this work, we propose a new nonparametric Phase I control chart for monitoring the scale parameter based on the empirical likelihood ratio test. The simulation results show that the proposed chart is more effective than the existing charts in terms of signal probability. A real example is used to demonstrate how the proposed chart can be applied in practice.read more
Citations
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Journal ArticleDOI
Phase-I monitoring of high-dimensional covariance matrix using an adaptive thresholding LASSO rule
TL;DR: The results of the simulation and real studies have revealed the advantage of the T-COV chart over the CE in quickly capturing and precisely diagnosing the deviation in the covariance matrix of the high-dimensional processes.
Journal ArticleDOI
A non-parametric CUSUM control chart for process distribution change detection and change type diagnosis
Shiwang Hou,Keming Yu +1 more
TL;DR: A log-likelihood-ratio-based non-parametric cumulative sum (CUSUM) control chart to monitor arbitrary distribution change and diagnose the detailed change type simultaneously is proposed.
Journal ArticleDOI
An Optimal Design of the Synthetic Coefficient of Variation Chart Based on the Median Run Length
TL;DR: The synthetic coefficient of variation (CV) chart is currently evaluated based only on the average run length (ARL), but as discussed by the authors evaluates the chart based on different percentiles of the run len...
Journal ArticleDOI
Monitoring and diagnostics of correlated quality variables of different types
TL;DR: In this article , the authors proposed a new phase II control chart based on a modified Holm's step-down multiple testing procedure (Holm 1979), which simultaneously monitors correlated variables of different types, while keeping the probability of false alarm under a desirable level.
References
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Journal ArticleDOI
Robust Tests for the Equality of Variances
Morton B. Brown,Alan B. Forsythe +1 more
TL;DR: In this paper, alternative formulations of Levene's test statistic for equality of variances are found to be robust under nonnormality, using more robust estimators of central location in place of the mean.
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Empirical likelihood ratio confidence intervals for a single functional
TL;DR: In this article, the empirical distribution function based on a sample is used to define a likelihood ratio function for distributions, which can be used to construct confidence intervals for the sample mean, for a class of M-estimates that includes quantiles, and for differentiable statistical functionals.
Journal ArticleDOI
Empirical Likelihood Ratio Confidence Regions
TL;DR: In this article, an empirical likelihood ratio function is defined and used to obtain confidence regions for vector valued statistical functionals, and an effective method is presented for computing empirical profile likelihoods for the mean of a vector random variable.
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Research Issues and Ideas in Statistical Process Control
TL;DR: An overview of current research on control charting methods for process monitoring and improvement and a historical perspective and ideas for future research are given.
Journal ArticleDOI
Controversies and Contradictions in Statistical Process Control
TL;DR: The relationship between hypothesis testing and control charting, the role of theory and the modeling of control chart performance, the relative merits of competing methods, the relevance of research on statistical process control and even relevance of SPC itself are discussed in this article.