Managing Queues: Queuing Parameters Flashcards
Amount of customer arrivals within a time window
Arrival Rate (A)
Capacity
L / W
Ns / Ts
Lq / Wq
Amount of customers served per server
Service Rate (S)
S = A + (1 / W)
1 / Ts
A / Ns
Amount of time spent serving a customer per server
Ts
1 / S
Number of servers or channels in a facility
m
Average service rate of the facility
mS
m x S
m x (1 / Ts)
The percent of time servers are with customers
Utilization factor (u)
A / (mS)
Amount of customers being served
Ns
capacity utilization
A / S
A x Ts
m x u
Amount of customers in the service system
L
A / (S - A)
A x W
Ns + Lq
(amount of customers being served + amount of customers waiting in line)
Amount of customers waiting in line
Lq
Wq x A
Total time in the system
W
1 / (S - A)
L / A
Wq + (1 / S)
Amount of time spent waiting
Wq
W - (1 / S)
Lq / A
Interarrival time
between…arriving to
1 / A
