Page 121 - DCAP601_SIMULATION_AND_MODELING

Unit 7: Simulation of Queuing System (I)

2. Ascertaining the times of repeating simulation for reaching the precision  Notes

(a) Repeat simulation R (R  2) times independently, and set R = R
0 0 0
R
(b) Compute Y ( ),S 2 ( ) and absolute procession  (Ora). ( ),S 2 ( ) Are sample
R
R
R
Y
average value and variance after R times running, and  (Ora), is half length of the
Confidence Interval of R times running under significance degree.
Did u know? Event step-length method
Event step-length method takes the time of event as increment, and simulates the behaviors of
the system according to the process of time until the scheduled time ends.



Caselet The Value of Queuing Theory

rofessor Jack Byrd [Byrd, J. 1978. The value of queueing theory. Interfaces 8 (3) 22-
26.], argues that queueing theory has little value to the practicing professional.
PProfessor Byrd bases his argument on a number of examples in which queueing
theory, as it exists today, appears to be inadequate to provide answers to the questions
being posed. The purpose of this article is to offer a rebuttal to the conclusions of Byrd's
paper. This rebuttal is in the form of a case study dealing with a command and control
problem. This case study is of general interest because there is a fundamental difference
between the question addressed in the case study discussed below and the questions
addressed by the examples in Byrd's paper.

7.4 Summary

 This unit has evaluated the performance of single-channel and multiple-channels queues
using the discrete-event simulation technique.

 In a queuing system, the calling population is assumed to be infinite that is, if a unit leaves
the calling population and joins the waiting line or enters service; there is no change in the
arrival rate.
 The single-channel queuing system can be seen in places such as banks and post offices,
where one single queue will diverge into a few counters.

 The multiple-channels queuing system is commonly observed in fast food restaurants
like KFC, Burger King, McDonalds, etc. It is a system whereby the customers line up in
rows directly in front of each server.
 Queuing Theory arises from the use of powerful mathematical analysis to theoretically
describe production processes along with statistical/probabilistic techniques to account
for varying dynamic patterns within the stages of a productive process.
 The computer simulation is a method that demonstrates dynamically the structure and the
behaviors of a system with computer in order to evaluate and predict the effect of the
behaviors of some system and provide information for decision.

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