논문 상세보기
When the production run is short and process parameters change frequently, it is difficult to monitor the process using traditional control charts. In such a case, the coefficient of variation (CV) is very useful for monitoring the process variability. The CV control chart is an effective tool to control the mean and variability of process simultaneously. The CV control chart, however, is not sensitive at small shifts in the magnitude of CV. The CV-EWMA(exponentially weighted moving average) control chart which was developed recently is effective in detecting a small shifts of CV. Since the CV-EWMA control chart scheme can be viewed as a weighted average of all past and current CV values, it is very sensitive to small change of mean and variability of the process. In this paper, we propose an FIR(Fast initial response) CV-EWMA control chart to improve the sensitivity of a CV-EWMA scheme at process start-up or out-of-control process. Moreover, we suggest the values of design parameters and show the results of the performance study of FIR CV-EWMA control chart by the use of average run length( ). Also, we compared the performance of FIR CV-EWMA control chart with that of the CV-EWMA control chart and we found that the CV-EWMA control chart gives longer in-control ARL and much shorter out-of-control ARL.
2. 변동계수의 통계적 특성과 확률분포
2.1 변동계수의 통계적 특성
2.2 변동계수의 확률분포
2.3 새로운 변동계수의 평균과 분산 추정방법
3. CV 관리도와 CV-EWMA 관리도
3.1 CV 관리도
3.2 CV-EWMA 관리도
4. FIR을 이용한 CV-EWMA 관리도
5. 관리도들의 수행도 분석과 평가
5.1 CV-EWMA 관리도와 FIR CV-EWMA관리도의 정확한 수행도 비교 및 평가
5.2 FIR CV-EWMA 관리도와 FIR CV-CUSUM관리도의 수행도 비교 및 평가
6. 결론
참고문헌
