UNIVERSITY EXAMINATIONS: 2017/2018
EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE IN
INFORMATION TECHNOLOGY/ BACHELOR OF BUSINESS IN
INFORMATION TECHNOLOGY
BIT2201 SIMULATION AND MODELING
FULL TIME/PART TIME/DISTANCE LEARNING
DATE: APRIL 2018 TIME: 2 HOURS
Instructions: Answer Question 1 and any other TWO Questions.
QUESTION ONE: 30 MARKS (COMPULSORY)
a) Discuss the two short comings of the mid-square method as generator of random numbers.
4 Marks
b) Using the Linear Congruential Generator (LCG) with a=67, m=31, c=17 and seed Z0 = 117 to
generate the first FIVE random variates on [0,1]. 6 Marks
c) Using appropriate examples identify four main types of system. 6 Marks
d) Simulation models are not the only models that can be used for understanding and improving
the real world. There exist other modeling approaches. Why would simulation be used in
preference to these other modeling approaches? 6 Marks
e) With the help of well labeled diagrams illustrate and describe the four types of queues that
exist giving common place examples. 8 Marks
QUESTION TWO: 20 MARKS
a) Describe five common statistics included in the output report of a simulation programming
system. ` 10 Marks
The table below shows the probability distribution of a barges arriver per day at a port.
The unloading rate per day follows the probability distribution given below. NB: unloading is
done on FCFS basis.
Suppose the following are the random numbers of arrivals and random numbers of unloading.
Arrival Random No. 53, 07, 51, 82, 50, 35, 12, 57, 99, 27, 56, 93, 35, 34, 00, 22, 31
Unload Random No. 35, 66, 38, 12, 54, 75, 34, 05, 19, 70, 64, 85 90, 73, 59 61, 43
Required: determine: simulate a seventeen day analysis and determine:
i. The average number of barges delayed 4 Marks
ii. The average number of arrivals per day 3 Marks
iii. The average number of barges offloaded each day 3 Marks
QUESTION THREE: 20 MARKS
a) Define the terms verification and validation in the context of modeling. 4 Marks
b) Dynamic systems have a state that is ever changing as a result of changes in state variables.
In your own understanding describe the terms system, system state, and state variable
6 Marks
c) Not all simulation and modeling exercises are a success. Discuss five common pitfalls to
successful simulation. 5 Marks
d) Describe the factors that should be considered in selecting a simulation language.
5 Marks
QUESTION FOUR: 20 MARKS
a) State and briefly explain four properties of a good arithmetic random number generator.
b) Consider a single server queuing system. The system starts at time t=0. The arrival time of
customers is: 0.8, 1.4, 2.7, 3.2, 3.8, 8.0, 8.6, 9.0, 9.2, and 9.8. The departure times are: 2.2,
4.0, 5.0, 6.2, and 10.0. Time is in minutes. The first in first out queuing discipline is
followed. Simulate this system for six clients and estimate:
i) The average delay in the waiting line 3 Marks
ii) The average number of clients in the waiting line at any time t 5 Marks
iii) The expected utilization of server. 2 Marks
c) Differentiate between the following types of models 6 Marks
i. Deterministic Vs Stochastic Models
ii. Discrete Models Vs Continuous Models
QUESTION FIVE: 20 MARKS
a) Describe all the components found in most discrete event simulation models.
10 Marks
b) Using the mid- square method obtain the random variables using Z0= 7182 until the cycle
degenerates to zero. 10 Marks
