“…Table 1 shows the average waiting time of requests of STI-RD strategy with different T and dt when dt=0.25,0.5,1,2.5,5. As can be seen from the table that, If T~(0,5), the average waiting time of requests is shortest when dt=0.25; if T~ [5,25] , the average waiting time of requests is shortest when dt=0.5. So we should select dt=0.25 if T~(0,5) and select dt=0.5 if T~ [5,25].…”