Estimation of the Starting Time of a Step Change Disturbance in a Gamma Process

估計GAMMA製程中階梯式干擾啓始時間點之研究

10.29977/JCIIE.200607.0006

邵曰仁(Yuehjen E. Shao)；侯家鼎(Chia-Ding Hou)

SPC管制圖 ； gamma製程 ； 干擾 ； 最大槪似估計 ； SPC chart ； gamma process ； disturbance ； maximum likelihood estimation

工業工程學刊

23卷4期（2006 / 07 / 01）

319 - 327

英文

由於估計製程干擾的啟始時間點能快速地決定失控製程的根本原因，因而成為製程改善的重要研究主題之一。不同於傳統常態製程之假設，本文探討如何使用(平均值)X管制圖以監督Gamma製程。當失控訊號產生時，我們提出一有效方法以估計製程干擾的啟始時間點；同時，本文將藉由模擬範例以評估我們所提方法之效能。

Due to the quick determination of the root causes for an out-of-control process, the estimation of the starting time of a process disturbance becomes an important issue for the process improvement. In contrast to the typical assumption that the process is normal, this study realizes that the process may follow a gamma distribution. For this reason an (average)X control chart was employed to monitor the gamma process. When an out-of-control signal is triggered, we propose a fruitful approach for estimating the starting time of a process disturbance. A series of simulations were conducted to evaluate the performance of the proposed approach.

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