COURSE CODE: CIT3 342
COURSE TITTLE: Formal Languages And
Automata Theory
TIME ALLOWED: 2hrs
Instructions: Answer any 5 questions. Each
questions carries 14 marks
1a. state Gödel incompleteness theorem
2marks
b. define context-sensitive grammars
2marks
c. write short note on decision
problems 3marks
d. When is a formal system said to be:
i. Complete?
ii. Inconsistence? 2marks
e. Let V be a set of strings. Does V+=V*?
justify your answer 3marks
2a. List any 4 types of automata and state
their respective recognizable language
b. in the context of automata theory. Briefly
describe the following terms
i. Recognized Language
ii. Run
iii. Transducer
3a. what is sentential form? 2marks
b. consider the linear grammar ({S,B.{a,b},S,
{S—aS, S—B,B—bB,B---b}}) give any
three sentential form of this grammar
3marks
c. List and describe the various components
of a formal grammar 6marks
d what do you understand by the term
automata theory? 3marks
4a. A non-deterministic finite automaton is
not more powerful than a determine finite
automaton. Discuss. 4marks
b. thinking of an automation as a computer,
state the ways it can handle non-
determinism? 3marks
c. state two of the ways of implementing a
DFA 2marks
d. with respect to regular expressions, what
is the precedence of the following operations
relative to one another? 4marks
i. Kleene Star
ii. Concatenation
iii. Union
5a. Distinguish between context-free
grammar and regular grammar
4marks
b. List the three ways of defining a language
4marks
c. formally define an automation
5marks
6a. Describe any three of the popular
variation in the definitions of different
components of
Automata
b.What is/are the use(s) of Greibach Normal
Form? 2marks
7a. state the formal definition of
PDA 7marks
b. List and describe the types of
PDAs. 4marks
c. Distinguish Between an alphabet and a
language 3marks
MARCH/APRIL 2016 EXAMINATION
SCHOOL OF SCIENCE AND TECHNOLOGY
COURSE CPDE: CIT 303
COURSE TITLE: PRINCIPLES OF
COMMUNICATION
TIME ALLOWED: 3 HOURS
COURSE CREDIT UNIT: 3
INSTRUCTION: ATTEMPT ANY FIVE
QUESTIONS. EACH QUESTION CARRIES 14
MARKS
Question 1
a. outline the layers of Open System
Interconnection Reference Model (OSI model), in
the right order.
b. write briefly on the physical layer.
c. cryptography algorithms (ciphers) can be
divided into two groups
Question 2
a. with the aid of a table ONLY, describe the
five classes of IP addresses under the following
fields:
i. IP Address Class
ii. Format
iii. Purpose
iv. Number of network/host bits
v. max number of hosts.
b. Briefly explain each of the following terms:
i. Linear filter
ii. Stable filter
iii. Unstable filter
vi. time-invariant filter.
v. adaptive filter
vi. Linearity (in the context of linear-time
invariant (LTI))
Question 3a. Encrypt the word “IGNORANCE"
with the following ciphers:
Shift cipher with key=1 i.
Shift cipher with key=26 ii.
Shift cipher with key=0 iii.
Transposition cipher
where plain text: 1 2 3 4 5 6 7 8 9
and cipher text: 4 3 1 5 2 6 7 9 8
(with no bogus character)
iv.
b. decrypt the word “ANCEIGNOR” with the
following ciphers:
Shift
cipher with key=1
i.
Shift
cipher with key=26
ii.
Shift
cipher with key=0
iii.
Transposition cipher where plain
text 1 2 3 4 5 6 7 8 9 and cipher text 4 3 1 5 2
6 7 9 8(with no bogus character)
iv.
The amplification in a cable is usually defined in
decibels per kilometer (dfl/km). If the signal at
the beginning of a cable with 2 dfl/km has a
power of 2 mW, what is the power of the signal
at 5 km?
Briefly explain the term attenuation.
Question 4
a. what us data communications
b. define protocols
c. The effectiveness of a data communications
system depends on four fundamental
characteristics. List and define these
characteristics.
Question 5
Contrast between
a. analog signal processing and digital signal
processing
b. OSI presentation layer and OSI application
layer
c. symmetric-key and asymmetric-key
Question 6
a. define the term “network topology”
b. with the aid of diagrams, briefly explain the
following network topologies:
Ring i.
Mesh ii.
Tree iii.
c. state and briefly explain 3 advantages if
using fiber optic cables in networking.
d. state 1 advantage and 2 disadvantages of
STP cables in comparison to UTP cables.
COURSE CODE: CIT3 305
COURSE TITTLE: NETWORKING AND
COMMUNICATION TECHNOLOGY
TIME ALLOWED: 3hrs
Instructions: ANSWER ANY 5 QUESTIONS
1a. Briefly describe what a virtual private
Network is?
b. write down four reasons for creating
computers networks.
2a.Briefly explain the difference between
Ethernet and Gigabit Ethernet
b.write short notes on the following types of
physical media:
i. Unshielded Twisted Pair(UTP) cable
ii. Fibre-optic cable
iii. Coaxial cable
3a. Describe the Network Layer of the OST
Reference model
b. Write a brief note on the IEEE802 11b Wi-
Fi standard
4a. Briefly describe the addressing and other
functions of the internet protocol (IP) in the
IPv4 internet suit
b. Briefly Explain Why TCp is considered a
reliable protocol
5a. Explain briefly four threats that may face
an enterprise network that is connected to
the Internet
b. Distinguish between a Man and a WAN
6a. Give a brief description of the following
i. Multiplexer
ii.Modem
b. Briefly Explain the following aspect of
Network planning and designs:
i. Business requirements
ii. Proof of concept
7a. Describe four types of noise, indicating
which type is particularly harmful to digital
data.
b. Give a brief description of the ISDN
technique highlighting its main advantage
over other communication techniques