t₀

Average time to process one job/part not counting queuing, setup or downtime at station.

C₀

Coefficient of variation (CV) of process time at station.

m_f

Mean time to failure.

m_r

Mean time to repair.

N_s

Average number of jobs between setups.

t_s

Average time to do a setup.

C_s

Coefficient of variation of the setup time.

r_b

Bottleneck rate, that is the rate of the process center having the highest long-term utilization.

T₀

Raw process time, that is, the sum of the long-term average process times of each station in the line.

a

Congestion coefficient, an unitless measure of congestion. For example, a = 0, when there is no variability and a increases as variability increases.