The Continuous Run Sum Chart |
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Authors: | Cesar A. Acosta-Mejia Luis Rincon |
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Affiliation: | 1. Department of Industrial Engineering, Instituto Tecnologico Autonomo de Mexico, Mexico City, Mexico;2. Departamento de Matemáticas, Facultad de Ciencias UNAM, Circuito Exterior de CU, México |
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Abstract: | The run sum chart is an effective two-sided chart that can be used to monitor for process changes. It is known that it is more sensible than the Shewhart chart with runs rules and its performance improves as the number of regions increases. However, as the number of regions increses the resulting chart has more parameters to be defined and its design becomes more involved. In this article, we introduce a one-parameter run sum chart. This chart accumulates scores equal to the subgroup means and signals when the cummulative sum exceeds a limit value. A fast initial response feature is proposed and its run length distribution function is found by a set of recursive relations. We compare this chart with other charts suggested in the literature and find it competitive with the CUSUM, the FIR CUSUM, and the combined Shewhart FIR CUSUM schemes. |
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Keywords: | Combined Shewhart CUSUM scheme FIR CUSUM Run sum chart |
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