**UNIVERSITY EXAMINATIONS: 2018/2019**

**EXAMINATION FOR THE DEGREE OF BACHELOR OF SCIENCE IN **

**INFORMATION TECHNOLOGY / BACHELOR OF BUSINESS **

**INFORMATION TECHNOLOGY/ BACHELOR OF SCINCE IN APPLIED **

**COMPUTING**

**BIT 2201/BIT 308/BAC 2106: SIMULSTION AND MODELING**

**FULL TIME/PART TIME/DISTANCE LEARNING **

**DATE: APRIL, 2019 TIME: 2 HOURS**

**INSTRUCTIONS: Answer Question One & ANY OTHER TWO questions.**

**QUESTION ONE [30 MARKS]**

a) Define the term simulation? [2 Marks]

b) Explain the role of computers in simulation. [3 Marks]

c) State four short comings of the mid-square method as generator of random numbers.

[4 Marks]

d) Using appropriate examples distinguish between discrete event simulation and

continuous event simulation. [4 Marks]

e) Using a mixed congruential method to generate a sequence of five two-digit random

integer number such that

. [5 marks]

f) What is autocorrelation? How does it does it affect simulation analysis? [5 Marks]

g) With the help of a single queueing model having inter-arrival and service time constants

1.4

and

minutes respectively and taking

10

minutes as the simulation period .

Assume that initially the system is empty and the first customer arrives at time

t 0.

Determine the:

i. Average waiting time of a customer. [3 Marks]

ii. Average waiting time per customer for those who must wait.

[3 Marks]

iii. Percentage idle time of the facility. [1 Mark]

**QUESTION TWO [20 MARKS]**

a) Not simulation and modeling exercises are a success. Discuss five common pitfalls to

successful simulation. [5 Marks]

b) According to the test, a Poisson deviate with parameter

can be generated by

finding the number of exponential random deviates used to satisfy the following

inequality.

the

th i random number in a sequence of random numbers. Verify this

fact. [7 Marks]

c) With the help of labeled diagrams illustrate and describe the four types of queues

that exists giving common place examples. [8 Marks]

**QUESTION THREE [20 MARKS]**

a) State four properties of a good random number generator. [4 Marks]

b) Define the terms verification and validation in the context of modeling.

[4 Marks]

c) A dentist schedules all his patients for

30 -minute appointments. Some of the patients

take more than

30

minutes, some less, depending on the type of dental work to be done.

The following summary shows that various categories of work, their probabilities and

time actually needed to complete the work.

Category of service Time required (minutes) Probability of category

Simulate the dentist’s clinic for four hours and determine the average waiting time for

the patients as well as the idleness of the doctor. Assume that all patients show up at the

clinic at exactly their scheduled time starting at 8:00 a.m. Use the following random

numbers for handling the above problem:

40, 82, 11, 34, 25, 66, 17, 79

[12 Marks]

**QUESTION FOUR [20 MARKS]**

a) Describe the three factors that should be considered when selecting a simulation

language. [6 Marks]

b) Discuss the Monte Carlo simulation method of solving problem, illustrating it by

outlining a procedure to solve a specified problem of your choice. [8 Marks]

c) Distinguish between solutions derived from simulation models and solutions derived

from analytical models? [6 Marks]

**QUESTION FIVE [20 MARKS]**

a) Explain the three factors to consider when designing a simulation experiment.

[6 Marks]

b) A confectioner sells confectionary items. Past data of demand per week (in hundred

grams) with frequency is given below:

Demand/week

Using the following sequence of random numbers

35, 52, 90,13, 23, 73, 34, 57, 35,83, 94, 56, 67, 66, 60

generate the demand for the next

15

weeks .

(i) Using the formula determine the expected demand per week. [3 Marks]

(ii) Determine the average demand per week using the simulated data. [3 Marks]

(iii)Comment on the results in (i) and (ii). [2 Marks]

c) 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]

END