Run-length distribution for Shewhart control charts with runs rules

초록

The Shewhart control chart is simple to apply to the actual production process. When the change is large, it is sensitive to detect the changes. However, if the change is small, it is not sensitive. Several methods have been developed to improve the sensitivity of the Shewhart control chart. Western Electronic Company applied runs rules to have sensitivity in cases of small shifts. To calculate the ARL of the control chart, we use the finite Markov chain imbedding method of Fu and Koutras and calculate ARLs in cases of several mean and variance shifts. In this thesis, according to the small shifts in mean and variance, the two control charts were compared through ARL. The control chart with runs rules has been more decreased ARL in small shifts compared the traditional Shewhart control charts. That is, it can be seen that the control chart with runs rules detects more sensitively than the Shewhart control chart when there are small shifts.

키워드