A New CUSUM-S2 Control Chart for Monitoring the Process Variance
In this paper the statistical performance of a CUSUM-S2 control chart designed to monitor the dispersion of a normally distributed process quality parameter is investigated. The proposed chart monitors a statistic computed as a logarithmic transformation of the sample variance; the introduction of the sample variance logarithmic transformation has a twofold e ect: i) to quickly detect the occurrence of an out-of-control condition; ii) to deal with a quasi-standard normal statistic. A design strategy trying to minimize the out-of-control Average Run Lenght (ARL) of the chart is presented and the statistical performance of the CUSUM-S2 chart has been assessed through a comparison with an EWMA-S2 control chart proposed in literature to monitor the process dispersion. The obtained results show how the CUSUM-S2 chart is particularly suitable when a reduction in the process dispersion should be detected by means of subgroups having limited sample sizes.
Sample Variance CUSUM Logarithmic Transformation Average Run Lenght
Philippe CASTAGLIOLA Giovanni CELANO Sergio FICHERA
Universite de Nantes & IRCCyN UMR CNRS 6597,Carquefou,France Universita di Catania,Catania,Italy
国际会议
北京
英文
2007-05-30（万方平台首次上网日期，不代表论文的发表时间）