Economic design of EWMA control charts based on loss function
Mathematical and Computer Modelling
Serel, D. A. (2009). Economic design of EWMA control charts based on loss function. Mathematical and Computer Modelling, 49(3), 745-759.
Please cite this item using this persistent URLhttp://hdl.handle.net/11693/11648
For monitoring the stability of a process, various control charts based on exponentially weighted moving average (EWMA) statistics have been proposed in the literature. We study the economic design of EWMA-based mean and dispersion charts when a linear, quadratic, or exponential loss function is used for computing the costs arising from poor quality. The chart parameters (sample size, sampling interval, control limits and smoothing constant) minimizing the overall cost of the control scheme are determined via computational methods. Using numerical examples, we compare the performances of the EWMA charts with Shewhart X and S charts, and investigate the sensitivity of the chart parameters to changes in process parameters and loss functions. Numerical results imply that rather than sample size or control limits, the users need to adjust the sampling interval in response to changes in the cost of poor quality. © 2008 Elsevier Ltd. All rights reserved.
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