공정 변화를 감지하기 위한 VSI 계수치 관리도의 최적 설계

The analyses and results in this research differ from previous studies of the SPC problem in five ways. First, the results of the factorial experiment obtained by various parameter circumstances show that the VSI control chart using nearly unbiased ATS design provides the smallest decreasing rate in ATS other charts for all experimental cases. Second, we illustrate that the control limits on the VSI control chart using Shewhart method cannot satisfy false alarms when control parameter are small. Third, we represent that a process change is rapidly in detected when short sampling interval approximate to . In addition, the change of the sampling interval may not influence in a set of control chart parameters. Fourth, we demonstrate that ATS curve has large bias establshing the parameter of VSI control chart using the Shewhart method. However, the proposed design method for the development of a control chart robust of sample size and control parameter size. Finally, we present an optimization model that may efficiently provide optimal ATS values for process parameters in a steady state, and that may efficiently establish parameters of correct control char by supplying an optimization algorithm.