Journal ArticleDOI
X̄ charts with variable sample size
TLDR
In this article, the authors considered the properties of the X chart when the size of each sample depends on what is observed in the preceding hours and the usual practice in using a control chart to monitor a process is to take samples of size n from the process every h hours.Abstract:
The usual practice in using a control chart to monitor a process is to take samples of size n from the process every h hours. This article considers the properties of the X chart when the size of each sample depends on what is observed in the preceding ..read more
Citations
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Journal ArticleDOI
Optimal decision in a Statistical Process Control with cubic loss
TL;DR: This work considers the problem of time-sampling optimization for a Statistical Process Control (SPC) and chooses the expected loss as a cubic polynomial function of this delay, which is justified by some real-life problems.
Journal ArticleDOI
An approach for improvements on the attribute npx$np_x$ control chart
TL;DR: In this article , an attribute control chart named npx(I)μ$np{x(I)}^{\mu }$ is proposed for monitoring the process mean value of a variable (X) by employing sequential sample sizes of na$n_a$ , nb$n-b$ with na>nb$n/a> n/b$ . Each item is classified as approved or not according to a discriminant limit ( wi$w_i$ , i=a,b$i=a.
Utilização do Controle Estatístico de Processo para o Monitoramento da Qualidade do Biodiesel Produzido pela Usina Alfa Use of the Statistical Control of Process for the monitoring of the quality of the Biodiesel produced by Alfa power plant
TL;DR: In this paper, the authors apply the Statistical Process Control (SPC) methodology in a biodiesel Power Plant located in the Northeast of Brazil that has an impressive estimated production capacity in regional and national scopes.
Journal ArticleDOI
Utilização do controle estatístico de processo para o monitoramento da qualidade do biodiesel produzido pela Usina Alfa
TL;DR: In this article, a metodologia do Controle Estatistico de Processos (CEP) was applied to a usina de biodiesel in the regiao nordeste do Brazil.
Proceedings ArticleDOI
An adaptive Shewhart chart with varying sample statistic to control bivariate processes
Abstract: In this article, we propose a single mean chart to control bivariate processes. The basic idea is to double the size of the samples, once only one of the two quality characteristics, X or Y, is measured and only one of the two sample statistics is computed, or the mean of the X observations or the mean of the Y observations. The statistic that was used to obtain the current point and the current point’s position define the statistic for the next sample. If the current point is the mean of the X observations and it is in the central region, then the control of X is relaxed and the focus goes to Y, that is, the charting statistic for the next sample will be the mean of the Y observations. On the other hand, if the current point is in the warning region, the focus remains on X, that is, the charting statistic for the next sample will be the mean of the X observations. A similar rule is applied when the current statistic is the mean of the Y observations. Thanks to the adaptive feature of the proposed chart, the degree of dependence between X and Y plays no hole in chart’s performance. The adaptive chart is overwhelmingly faster than the Hotelling chart in signaling all kinds of disturbances.
References
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Journal ArticleDOI
X charts with variable sampling intervals
TL;DR: The variable sampling interval (VSI) chart as discussed by the authors uses a short sampling interval if the sample is close to but not actually outside the control limits, and a long sampling interval for the sample if it is closer to target.
Journal ArticleDOI
Combined Shewhart-CUSUM Quality Control Schemes
TL;DR: The SheWhart-CUSUM quality control scheme which combines the key features of the Shewhart and CUSUM control procedures is described and evaluated.
Journal ArticleDOI
A Combined Adaptive Sample Size and Sampling Interval X Control Scheme
TL;DR: In this paper, a combine X control chart is proposed, where the process control engineer waits until the control scheme signals an out-of-control condition, and then the process can be restarted.
Journal Article
Double sampling X charts
TL;DR: In this article, the double sampling X chart is proposed, which is the counterpart to double sampling plans, which offers better statistical efficiency (in terms of statistical efficiency) than double sampling plan.
Journal ArticleDOI
Double Sampling X̅ Charts
TL;DR: The purpose of this paper is to propose a new control chart, the double sampling X chart, which is the counterpart to double sampling plans, which offers better statistical efficiency.