Journal ArticleDOI
A control chart for the Gamma distribution as a model of time between events
TLDR
In this article, a random-shift model for calculating the out-of-control average time to signal (ATS) of the Gamma chart is developed, which is shown to be much more accurate than the conventional method based on a fixed shift model through comparing with Monte Carlo simulation.Abstract:
In this paper, control charts for monitoring exponentially distributed time between events (TBE) are studied. In particular, a Gamma chart which monitors the time until the rth event is proposed and investigated. A new method based on a random-shift model for calculating the out-of-control average time to signal (ATS) of the Gamma chart is developed. It is shown to be much more accurate than the conventional method based on a fixed-shift model through comparing with Monte Carlo simulation. A comparison is also made among the exponential, the Gamma and the exponential CUSUM charts, which shows that the Gamma chart is more sensitive than the exponential chart and the performance of a Gamma chart with r = 4 is comparable with that of an exponential CUSUM optimally designed. However, the advantage of the Gamma chart is the ease involved in the design, evaluation and implementation. The use of the Gamma chart is illustrated with two real and one simulated examples.read more
Citations
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Journal ArticleDOI
An analysis of fatal gas accidents in Chinese coal mines
TL;DR: In this paper, the influence of coal mine ownership, gas content in coal and coal and regions of coal mines on safety is determined quantitatively, and the accidents are grouped by cause.
Journal ArticleDOI
Exponential CUSUM Charts with Estimated Control Limits
TL;DR: The effect of parameter estimation on the run length properties of one-sided lower exponential CUSUM charts is investigated and the effect of estimation error can be significant, affecting both the in-control average run length and the quick detection of process deterioration.
Journal ArticleDOI
An Overview of Control Charts for High‐quality Processes
TL;DR: Time-between-events control charts detect an out-of-control situation without great loss of sensitivity as compared with existing charts, and draw a precise conclusion from the statistical point of view.
Journal ArticleDOI
An economically designed, integrated quality and maintenance model using an adaptive Shewhart chart
Sofia Panagiotidou,George Nenes +1 more
TL;DR: A model for the economic design of a variable-parameter Shewhart control chart used to monitor the mean in a process, where, apart from quality shifts, failures may also occur, allows the determination of the scheme parameters that minimize the total expected quality and maintenance cost of the procedure.
Journal ArticleDOI
A combined synthetic&X chart for monitoring the process mean
TL;DR: The Syn-X chart as discussed by the authors combines a synthetic chart and a Shewhart X chart to monitor the mean of a quality characteristic x. This chart decides the process status based on the magnitude of the sample mean x and is effective for detecting large mean shifts.
References
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Journal ArticleDOI
The Economic Design of Control Charts: A Unified Approach
TL;DR: In this article, the choice of control chart parameters (sample size, sampling interval, and control limits) is considered from an economic point of view, and a general process model is considered, and the hourly cost function is derived.
Journal ArticleDOI
Counted Data CUSUM's
TL;DR: Design and implementation procedures for counted data CUSUM's (these are sometimes called C USUM's for attributes) are described, which are easy to design and implement and can be used to detect both increases and decreases in the count level.
Journal ArticleDOI
Some effective control chart procedures for reliability monitoring
TL;DR: A recent control scheme based on the cumulative quantity between observations of defects has been proposed which can be easily adopted to monitor the failure process for exponentially distributed inter-failure time and can detect process improvement even in a high-reliability environment.
Journal Article
Detecting a shift in fraction nonconforming using runlength control charts with 100% inspection
TL;DR: When 100% inspection in the order of production is in progress, an alternative approach to the p-chart or the Poisson-based CUSUM chart is to monitor the lengths of runs of conforming items between successive nonconforming items.
Journal ArticleDOI
Detecting a Shift in Fraction Nonconforming Using Run-Length Control Charts with 100% Inspection
TL;DR: When 100% inspection in the order of production is in progress, an alternative approach to the p-chart or the Poisson-based CUSUM chart is to monitor the lengths of runs of conforming items between successive nonconforming items.