Multivariate $T^2$ Variable Interval Control Chart with Sampling at Fixed Times

고정표본채취시점을 갖는 가변표본채취간격 다변량 $T^2$관리도

This paper proposes a multivariate $T^2$ variable interval control chart with sampling at fixed times, where samples are taken at specified equally spared fixed time points, and additional samples are allowed between these fixed times when indicated by the preceding $T^2$ statistics. At fixed sampling tunes, the $T^2$ statistics are composed of all quality characteristics, and a part of qualify characteristics are selected to obtain $T^2$ statistics at additional sampling times. A Markov chain approach is used to evaluate the performance of the proposed chart.