An improved VSSI Multivariate Coefficient of Variation Chart

In this paper,an improved version of variable sample size and sampling interval multivariate coefficient of variation chart utilizing three sampling intervals and two sample sizes ,named the improved VSSI MCV chart,is suggested to conquer the weak point of the VSSI MCV control chart(varied between ۲ sampling intervals and ۲ sample sizes) and monitor multivariate coefficient of variation (MCV) in detecting small and moderate MCV shifts.The suggested chart is prepared utilizing the markov chain approach and it is contrasted with the existing VSSI MCV chart using the average time to signal (ATS),standard deviation of the time to signal (SDTS) and expected average time to signal (EATS) criteria.The performance contrast illustrates that the proposed improved MCV chart,outperform the existing VSSI MCV chart ,in terms of the ATS and EATS criteria.By letting the sample size and sampling interval to be more differed in the VSSI MCV chart,process engineers will have better control in process monitoring and concurrently can detect an out-of-control signal faster.

کلیدواژه ها:

Quality Control ، Multivariate Coefficient of Variation(MCV) ، Adaptive Control charts ، Average Time to Signal(ATS) ، Expected Average Time to Signal(EATS) ، Markov Chain.