QUEUEING THEORY 1

1. QUEUEING THEORY 1 Consider the following examples: Customers waiting for hair cutting at a barber shop Customers waiting for bank service at a bank teller Customers waiting for bar service at a cafeteria Customers waiting to pay at a supermarket cash desk Cars waiting to pay at a highway exit cash desk Cars waiting at traffic lights Trucks waiting to load or unload at a dock Airplanes waiting to take off at a runway

2. QUEUEING THEORY 2 Consider the following examples: Items waiting to be processed by a machine Machines waiting to be repaired for maintenance Items waiting to be inspected at a quality control desk Jobs waiting to be executed by a computer Documents waiting to be signed in an office Bills waiting to be processed at a legislative system �����������������������

3. QUEUEING THEORY 3 All above examples are queues (or waiting lines): Customers wait for a service as the service capacity is not sufficient to supply the service at once

4. QUEUEING THEORY 4 Basic structure of a queueing model Customers are generated by an input source Customers arrive according to an arrival rule Customers enter the system by joining a queue A customer is chosen according to a queue discipline The chosen customer obtains the required service The service follows a service rule The customer who obtained the service exits the system

5. QUEUEING THEORY 5 Basic structure of a queueing model