UNIVERSITY EXAMINATIONS: 2011/2012
YEAR 2 EXAMINATION FOR THE BACHELOR OF SCIENCE IN
INFORMATION TECHNOLOGY
BIT 2201 SIMULATION AND MODELLING
DATE: APRIL 2012 TIME: 2 HOURS
INSTRUCTIONS: Answer Question One and Any other Two Questions
QUESTION ONE
a) Define the following terms as used in simulation and modeling:
i) simulation
ii) system image
iii)state variable
iv)simulation algorithm
v) queue
(10 Marks)
b) Differentiate the following terms:
i) Point estimate and interval estimate
ii) Verification and validation
(8 Marks)
c) What are the effects of dynamic complexity in a system? (3 Marks)
d) Use a mixed linear congruential random number generator with a=71, m=31, c=17 and seed X0 =
117 to generate the first FIVE random variates on[0,1] (5 Marks)
e) Giving an example in each case, describe the following methods of describing logic for discrete
event simulation.
i) Event – Oriented
ii) Process – Oriented (4 Marks)
QUESTION TWO
a) List and discuss any FOUR disadvantages of simulation. (12 Marks)
b) Discuss how simulation and modeling can help a bank facing serious
Congestion problems in the banking hall overcome the problem. (8Marks)
QUESTION THREE
a) Consider a single server queuing system. The system starts at time t=0. The arrival times are: 1.1,
1.4, 2.3, 2.5, 2.7, 3.3, 4.0, 5.4, 5.9, 7.0, 7.8, and 8.6. The departure times are: 2.6, 3.0, 4.2, 8.0 and
10. Time is in minutes.
Simulate this system for six customers and hence estimate,
i) Expected average delay of a customer in the waiting line
ii) Expected average number of customers in the waiting line
iii) Expected utilization of Server.
(12 Marks)
b) Explain clearly how one can build a valid and credible model. (8 Marks)
QUESTION FOUR
a) Most simulation programming systems include a report generator to print out statistics gathered
during the run. Describe any FIVE common required statistics, which are usually included in the
output. (10 Marks)
b) The time taken to process print jobs by a computer is given by:
Test at 5% significant level whether this time follows an exponential distribution. (10 Marks)
QUESTION FIVE
a) Among the most compelling reasons for using simulation are the benefits gained by managers.
Explain any THREE benefits. (9 Marks)
b) Explain why animation is appropriate in explaining the behavior of a model when it is completed.
(3 Marks)
c) Describe any FOUR factors that should be considered when selecting simulation software.
(8 Marks)
