Waiting Line Theory Flashcards
Someone or something that is in
need of some type of service
Customer or element
a process or system that
performs the services to the
customer
Service facility
represents any type of attention
to satisfy customer or element
needs
Service
“The flow of customers from an infinite or finite population towards the service facility forms a queue or waiting line on account of lack of capability to serve all at a time.”
Service station
Number of customers waiting to be serviced.
Queue
A system having a service facility at which units of some kind (generically called “customers”) arrive for service
Queueing system
- Danish telephone engineer who did the original work on queueing theory.
- Effects on fluctuation demand on the utilization of automatic dialing equipment.
- By the end of World War II, waiting line models were extended to other kinds of problems.
A.K. Erlang, 1905
Four basic structures of waiting line theory
- Single Phase, Multiple Channel
- Single Phase, Single Channel
- Multiple Phase, Single Channel
- Multiple Phase, Multiple Channel
2 possible situations for a customer to acquire the service needed
- From customer to service center
- From service center to customer
When the customer is the one waiting…
- total number of customers > numher of facilities available
When the service center is the one waiting…
- total capacity of their system < total number of customers requiring service
Congestion
theoretical analysis of the waiting
line problem in telephone calls
A.K. Erlang, 1903
Developed the theory further
Mills and Thornton Fry, 1927
systematic and mathematical
approach to waiting line problem
David George Kendall, 1951
computerized reservation of
rail journey
1951 onwards
Queue Process
Arrival -> Waiting line -> Units served -> Leaving the queue
_____ __ ______ to the service system greatly depends on the nature of size of the population, which may be infinite or finite.
Size of arrivals
Arrival time distribution, customers arrive in Poisson or Completely random fashion.
Constant or Random
In queuing context, it refers to the space available for the arrivals to wait before being taken to service. The space available may be limited or unlimited.
Capacity of the Service System
The length of the queue or the waiting time of a customer or the idle time of the service facility mostly depends on the ________ _______
Customer Behavior