In the literature, many control charts monitoring the median is designed under a perfect condition that there is no measurement error. This may make the practitioners confusing to apply these control charts because the measurement error is the true problem in practice. In this paper, we consider the effect of measurement error on the performance of the exponentially weighted moving average (EWMA) control chart combining with the variable sampling interval (VSI) strategy. A linear covariate error model is supposed to model the measurement error. The performance of the VSI EWMA median control chart is evaluated through the average time to signal. The numerical simulation shows that the measurement errors have a negative influence on the proposed chart.

中文翻译：

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存在测量误差的可变采样间隔指数加权移动平均中值控制图的设计

在文献中，许多监视中位数的控制图都是在没有测量误差的理想条件下设计的。这可能会使从业人员难以应用这些控制图，因为测量误差实际上是真正的问题。在本文中，我们结合可变采样间隔（VSI）策略考虑了测量误差对指数加权移动平均（EWMA）控制图性能的影响。假设线性协变量误差模型可以对测量误差建模。通过平均发信号时间来评估VSI EWMA中值控制图的性能。数值模拟表明，测量误差对所提出的图表有负面影响。