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Showing 1 to 20 of 20 for “"Average run length"”.
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Design optimization for the two-stage bivariate pattern recognition scheme
… identification of process condition either it is running within in statistically in-control or out-of-control, whereas diagnosis refers to the identification of the source of out-of-control process. Selection of SPC scheme becomes more challenging when involving two correlated variables, which are …
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An optimization of on-line monitoring of simple linear and polynomial quality functions
… by using a Genetic Approach (GA). Here the average time to signal (ATS) and the average run length (ARL) are regarded as the objective functions, and ATS and ARL approximations, based on Markov Chain Principals, are extended and modified to capture the special structure of the profile …
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Applications of Control Charts in Medicine and Epidemiology
… rare health events. We compare the steady-state average run length performance of the Sets methods and its modifications to the Bernoulli CUSUM chart under a wide variety of circumstances. Except in a very few instances we find that the Bernoulli CUSUM chart performs better than the Sets method …
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Dynamic Probability Control Limits for Risk-Adjusted Bernoulli Cumulative Sum Charts
… for the chart leads to quite variable in-control average run length (ARL) performance for patient populations with different risk score distributions. To overcome this problem, the simulation-based dynamic probability control limits (DPCLs) patient-by-patient for the risk-adjusted Bernoulli CUSUM …
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EWMA and CUSUM control charts in the presence of correlation
… simulation approaches are used to evaluate the average run length (ARL) of exponentially weighted moving average (EWMA) and one-sided cumulative sum (CUSUM) control charts used to monitor the process. The effects of correlation and measurement error on the ARL's of the control charts are studied …
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Construction of fuzzy control charts by using triangular and gaussian fuzzy numbers for solder paste thickness
… of these control charts are compared by using average run length (ARL) to select the best chart to control the production process. Results showed that the new fuzzy control charts by using Gaussian fuzzy numbers are the best chart in monitoring the solder paste thickness showed by the lowest …
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Intergration of control chart and pattern recognizer for bivariate quality control
… Multivariate Exponentially Weighted Moving Average with Artificial Neural Network scheme provides superior performance, namely the Average Run Length for grand average ARL1 = 7.55 7.78 ( for out-of-control) and ARL0 = 491.03 (small mean shift) and 524.80 (large mean shift) in control process …
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A Performance Analysis of the Minimax Multivariate Quality Control Chart
… that are compared share identical in-control average run lengths (ARL) making the out-of-control ARL the appropriate performance measure. A combined Tausworthe pseudorandom number generator is used to generate the out-of-control mean vectors. Issues regarding multivariate uniform pseudorandom …
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A study on improving the performance of control charts under non-normal distributions
Generally, for constructing traditional control charts there are the two assumptions: that sample observations are statistically independent, and that the monitoring statistic follows a normal distribution. While the normality assumption is invalid in many cases, the traditional 3-sigma limits may …
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Univariate and Multivariate Surveillance Methods for Detecting Increases in Incidence Rates
… on a multivariate exponentially weighted moving average. The average run-length performance of this chart is compared with that of the existing methods.
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Analysis of the Family of Generalized Cumulative Sum Type Control Charts
… equations were derived for determining the run length distribution of the lower and upper one-sided charts. The Markov chain methods were also given. The parameters unknown version was presented and the performance analysis was studied for the chart for monitoring for a change in the mean of …
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Control chart procedures based on cumulative gauging scores
… sign score vector is also proposed. The exact run length distribution of these cumulative gauging score charts can be obtained by formulating the procedures as Markov chain processes. For some procedures, the average run length (ARL) can be obtained in a closed form expression by solving a …
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The Minimax control chart for multivariate quality control
… of the Chi-squared control chart in terms of the average run length for several combinations of the parameters of the chart. Among these parameters are the sample size, the number of variables, the probability of Type I error, the correlation matrix, and the direction and magnitude of the shift in …
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CUSUM Generalized Variance Charts
<p>The commonly recommended charts for monitoring the mean vector are affected by a shit in the covariance matrix. As in the univariate case, a chart for monitoring for a change in the covariance matrix should be examined first before examining the chart used to monitor for a change in the mean …
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Surveillance of Poisson and Multinomial Processes
… A modified exponentially weighted moving average (EWMA) chart is proposed to accommodate the varying sample sizes. The performance of this method is compared with the performance for several competing control chart techniques and recommendations are made regarding the best preforming …
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Statistical process control by quantile approach.
… be used to calculate process capability index, average run length (ARL), multivariate control chart and control chart for mixture distribution for non-normal situations. This methodology can be easily adopted by the practitioner of statistical process control.
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High-dimensional Online Changepoint Detection
… observations. We prove that the patience, or average run length under the null, of our procedure is at least at the desired nominal level, and provide guarantees on its response delay under the alternative that depend on the sparsity of the vector of mean change. Our procedure shows excellent …
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Prospective Spatio-Temporal Surveillance Methods for the Detection of Disease Clusters
… is considered by determining the in-control average run length (ARL) performance for different space and time closeness thresholds as well as for different control limit values. The effect of nonuniform population density and region shape on the in-control ARL is explained and some issues …
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Process Monitoring with Multivariate Data:Varying Sample Sizes and Linear Profiles
… The multivariate exponentially weighted moving average (MEWMA) control chart is one of the most commonly recommended tools for multivariate process monitoring. The standard practice, when using the MEWMA control chart, is to take samples of fixed size at regular sampling intervals for each …
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Monitoring for a Shift in a Process Covariance Matrix Using the Generalized Variance
… the Shewhart V and U charts supplemented with runs rules. Also, we examine the methods that are useful in studying the run length properties of the cumulative sum (CUSUM) U charts. Further, we will study the effect that estimating Σ₀ has on the performance of these charts. Guidance will be …