A study of wafer fab dispatching rules based on empirical flow time predictions

This study examined two dispatch rules-modified least slack rule and shortest remaining flow time rule. Both of these rules require future flow time prediction. We experimented with two flow time prediction methods-an exponential smoothing method and an iterative empirical curve approach. These new rules were compared with some other commonly used rules by simulation experiment. For the performance measure of mean flow time, the shortest remaining processing time rule performed best. Whereas, for the performance measure of standard deviation of flow time, the modified least slack rule with the flow time prediction by the iterative empirical curve approach performed best.