A Combination of CUSUM Charts for Monitoring a Zero-Inflated Poisson Process |
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Authors: | Shuguang He Shijie Li Zhen He |
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Institution: | 1. School of Management, Tianjin University, Tianjin, Chinashuguanghe@tju.edu.cn;3. School of Management, Tianjin University, Tianjin, China |
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Abstract: | The Zero-inflated Poisson distribution (ZIP) is used to model the defects in processes with a large number of zeros. We propose a control charting procedure using a combination of two cumulative sum (CUSUM) charts to detect increases in the parameters of ZIP process, one is a conforming run length (CRL) CUSUM chart and another is a zero truncated Poisson (ZTP) CUSUM chart. The control limits of the control charts are obtained using both Markov chain-based methods and simulations. Simulation experiments show that the proposed method outperforms an existing method. Finally, a real example is presented. |
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Keywords: | Average number of observations to signal CUSUM chart Markov chain ZIP process |
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