A variable sampling interval Shewhart control chart for monitoring the coefficient of variation in short production runs |
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| Authors: | Asma Amdouni Hassen Taleb Giovanni Celano |
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| Affiliation: | 1. Institut Supérieur de Gestion, Université de Tunis, Tunisia.;2. Higher Institute of Business and Accounting of Bizerte, University of Carthage, Tunisia.;3. Università di Catania, Catania, Italy. |
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| Abstract: | Monitoring the coefficient of variation (CV) allows process monitoring to be performed when both the process mean and the standard deviation are not constant but, nevertheless, proportional. Until now, few research papers have investigated the monitoring of the CV in a short production run context. This paper investigates the design and implementation of a Variable Sampling Interval Shewhart control chart to monitor the coefficient of variation in a short production run context. Formulas for the truncated average time to signal are derived and a performance comparison is carried out with a Fixed Sampling Rate Shewhart chart monitoring the CV. An example illustrates the use of this chart on real industrial data. |
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| Keywords: | Coefficient of variation variable sampling interval short production runs Markov chain truncated average time to signal |
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