A combined scheduling approach has been used for scheduling on the shopfloor . an interactive " pull " approach is used on the cell level and due date rule is used on the system on the system level . xu chunguang ( computer application ) directed by dr . huang yousen 采用“推拉”结合的调度机制,在单元级采用交互的“拉”式调度的方法,在系统级采用基于交货期规则的“推”式调度,实现了车间调度。