. Infinite Buffer Open Lines - Relationship of flow time with variability and utilization
The flow time for a station is proportional to the variability of the process and the arrivals, the utilization of the station, and the effective process time at the station. Letting V denote the variability term, U the utilization term and te the raw flow time of the station, the flow time in the queue (or waiting time) is
Flow Time in queue, FTq = V U te.
The variability V, in above depends both on the squared co-efficient of variation (SCV) of the processing times Ce2 and the squared coefficient of variation (SCV) of the interarrival times Ca2 and is given by:
.
The utilization is given as the following function of the traffic intensity u of the station:
.
Combining above, the flow time in queue for a station is given as:
.
Thus the total flow time (queue time plus process time) at a station is given as:
FT =FTq + te.