Parameters in Queuing Models (Multiple Servers, Multiple Queues Model)
n Number of total customers in the system (in queue plus in service)
c Number of parallel servers (Checkout sales operation units in ICA)
λ Arrival rate ( 1 / (average number of customers arriving in each queue in a system in one hour))
µ Serving rate ( 1 / (average number of customers being served at a server per hour))
cµ Serving rate when c > 1 in a system
ρ System intensity or load, utilization factor (= λ/(cµ) ) (the expected factor of time the server is busy that is, service capability being utilized on the average arriving customers)
Departure and arrival rate are state dependent and are in steady-state (equilibrium between events)
condition.