نتایج جستجو برای: ewma techniques
تعداد نتایج: 628987 فیلتر نتایج به سال:
In the originally proposed run-by-run control scheme, the EWMA statistic is used as an estimate of the process deviation from its target. However, the controller based on the EWMA statistic is not sufficient for controlling a wearing out process. The PCC controller has been thus proposed to enhance the run-by-run controller capability. In this paper, we first reexamine the fundamentals of the P...
In this paper, first the available single charting methods, which have been proposed to detect simultaneous shifts in a single process mean and variance, are reviewed. Then, by designing proper simulation studies these methods are evaluated in terms of in-control and out-ofcontrol average run length criteria (ARL). The results of these simulation experiments show that the EWMA and EWMS methods ...
The recently introduced triple exponentially weighted moving average (TEWMA) chart is the extended form of classical EWMA and double (DEWMA) charts. On other hand, auxiliary information-based (AIB) homogeneously ( HWMA AIB ) used for monitoring process location shifts ef...
In semiconductor manufacturing processes, mixed-products are usually fabricated on the same set of process tool with different recipes. Run-to-run controllers which based on the exponential weighted moving average (EWMA) statistic are probably the most frequently used in industry for the quality control of certain semiconductor manufacturing process steps. However, for mixed-product drifted pro...
Unlike a Shewhart chart, the exponentially weighted moving average (EWMA) and cumulative sum (CUSUM) charts are memory control charts (also known as time weighted control charts) that are used for a quick detection of small shifts in the process mean. Control charts that combine information from present and past samples, like the EWMA and CUSUM charts have the ability to detect process changes ...
Assuming a first-order auto-regressive model for the auto-correlation structure between observations, in this paper, a transformation method is first employed to eliminate the effect of auto-correlation. Then, a maximum likelihood estimator (MLE) of a step change in the parameters of the transformed model is derived and three separate EWMA control charts are used to monitor the parameters of th...
The EWMA quality control chart, and its multivariate version (MEWMA), may be designed to efficiently detect small shifts in the mean vector of a set of p quality characteristics of a production process. However, this work presents a method for the optimal design of the parameters of the MEWMA and EWMA charts to control processes where it is not convenient to detect small magnitude shifts and, a...
In this study, different ranked-based sampling (RBS) schemes are used to design a sensitive control chart monitor the small or moderate shifts in process mean and named combined EWMA moving average RBS (CEM-RBS) charts. The run-length (ARL) standard deviation of (SDRL) through Monte Carlo simulation runs computed evaluate performance proposed charts comparison with existing such as MA, EWMA, EW...
Quality control is an important role in industry for maintain quality stability. Statistical process can quickly investigate the occurrence of unforeseen causes or shifts using charts. Mixed Exponentially Weighted Moving Average - Cumulative Sum (MEC) chart a tool used to monitor and evaluate whether production not. The MEC method combination (EWMA) (CUSUM) Combining two charts aims increase se...
Background & Objectives: Evaluating the performance of outbreak detection methods using real data testing provide the highest degree of validity. The aim of this study was to determine the performance of the Exponentially Weighted Moving Average (EWMA) in real time detection of two local outbreaks in Iran. Methods: The EWMA algorithm (both ƛ= 0.3 and 0.6) applied on daily counts of suspected ca...
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