Comparison of monitoring the output variable and the input variable in the integrated process control

통합공정관리에서 출력변수와 입력변수를 탐지하는 절차의 비교

  • Lee, Jae-Heon (Department of Applied Statistics, Chung-Ang University)
  • 이재헌 (중앙대학교 응용통계학과)
  • Received : 2011.05.23
  • Accepted : 2011.06.23
  • Published : 2011.08.01


Two widely used approaches for improving the quality of the output of a process are statistical process control (SPC) and automatic process control (APC). In recent hybrid processes that combine aspects of the process and parts industries, process variations due to both the inherent wandering and special causes occur commonly, and thus simultaneous application of APC and SPC schemes is needed to effectively keep such processes close to target. The simultaneous implementation of APC and SPC schemes is called integrated process control (IPC). In the IPC procedure, the output variables are monitored during the process where adjustments are repeatedly done by its controller. For monitoring the APC-controlled process, control charts can be generally applied to the output variable. However, as an alternative, some authors suggested that monitoring the input variable may improve the chance of detection. In this paper, we evaluate the performance of several monitoring statistics, such as the output variable, the input variable, and the difference variable, for efficiently monitoring the APC-controlled process when we assume IMA(1,1) noise model with a minimum mean squared error adjustment policy.


Supported by : 한국연구재단


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