نتایج جستجو برای: shewhart control chart

تعداد نتایج: 1351146  

Journal: :Symmetry 2023

The implementation of Statistical Quality Control (SQC) has been tracked in various areas, such as agriculture, environment, industry, and health services. employment SQC methodologies is frequently employed for monitoring identification process irregularities across fields. This research proposes implements a novel methodology agricultural areas. A control chart one the tools that facilitates ...

Journal: :Revue scientifique et technique 2005
N Goris K De Clercq

Diagnostic laboratories are increasingly required to meet stringent quality standards, and validated assays are needed to achieve formal accreditation. Validation of test methods is often considered to be finalised when the assay parameters and characteristics have been established. However, like any process, diagnostic assays are subject to random variation resulting in shifts in the mean test...

2002
Zachary G. Stoumbos Joe H. Sullivan

Control charts are graphical tools widely used to monitor manufacturing processes to quickly detect any change in a process that may result in a change in product quality. The statistic plotted on a control chart is based on samples of n ≥ 1 observations (rational subgroups) that may be taken at regular sampling intervals. However, there are numerous practical applications using individual obse...

Journal: :Intelligent Automation and Soft Computing 2022

In this research, we propose the new mixed control chart called Moving Average-Cumulative Sum (MA-CUSUM) used for monitoring parameter changes in asymmetrical and symmetrical processes. Its efficiency was compared with that of Shewhart, Cumulative (CUSUM), Average (MA), Sum-Moving (CUSUM-MA) charts by using their average run lengths (ARLs), standard deviation length (SDRL), median (MRL) via Mon...

2017
Philippe Castagliola Fernanda Otilia Figueiredo Petros E. Maravelakis

• The usual CUSUM chart for the mean (CUSUM-X̄) is a chart used to quickly detect small to moderate shifts in a process. In presence of outliers, this chart is known to be more robust than other mean-based alternatives like the Shewhart mean chart but it is nevertheless affected by these unusual observations because the mean (X̄) itself is affected by the outliers. An outliers robust alternative ...

2005
Sven Bertelsen Lauri Koskela

Since the seminal contribution by Shewhart, the dominating approach to production is to minimize all variation in order to get the productive activities into control. Thus, the goal is to avoid all such complexity and uncertainty which could disturb this tight control. This approach is applied in lean production, which is considered to be the superior production template of today. It has to be ...

2012
Shabbir Ahmad Zhengyan Lin Saddam Akber Abbasi Muhammad Riaz

The presence of dispersion/variability in any process is understood and its careful monitoring may furnish the performance of any process. The interquartile range (IQR) is one of the dispersion measures based on lower and upper quartiles. For efficient monitoring of process dispersion, we have proposed auxiliary information based Shewhart-type IQR control charts (namely IQRr and IQRp charts) ba...

Journal: :Int. J. Computer Integrated Manufacturing 2011
F. Zandi Seyed Taghi Akhavan Niaki M. A. Nayeri M. Fathi

Despite the fact that control charts are able to trigger a signal when a process has changed, it does not indicate when the process change has begun. The time difference between the changing point and a signal of a control chart could cause confusions on the sources of the problems. Knowing the exact time of a process change would help to reduce the time for identification of the special cause....

Journal: :Health Informatics Journal 2021

Overcrowding in emergency departments (EDs) is a primary concern for hospital administration. They aim to efficiently manage patient demands and reducing stress the ED. Detection of abnormal ED (patient flows) systems aids managers obtain appropriate decisions by optimally allocating available resources following attendance. This paper presents monitoring strategy that provides an early alert w...

2000
Willem Albers

The influence of the estimation of parameters in Shewhart control charts is investigated. It is shown by simulation and asymptotics that (very) large sample sizes are needed to accurately determine control charts if estimators are plugged in. Correction terms are developed to get accurate control limits for common sample sizes in the in-control situation. Simulation and theory show that the new...

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