2013 - content.kopykitab.com6. a) what is the purpose of subnetting ? find the netid and the hostid...

Name : ……………………………………………………………

Roll No. : ………………………………………………………...

Invigilator's Signature : ……………………………………….

CS/B.Tech/CSE/New/SEM-6/CS-601/2013

2013DATABASE MANAGEMENT SYSTEM

Time Allotted : 3 Hours Full Marks : 70

The figures in the margin indicate full marks.

Candidates are required to give their answers in their own words

as far as practicable.

GROUP – A

( Multiple Choice Type Questions )

1. Choose the correct alternatives for the following :10 1 = 10

i) In the relational modes, cardinality is termed as

a) number of tuples

b) number of attributes

c) number of tables

d) number of constraints.

ii) Relational calculus is a

a) procedural language

b) non-procedural language

c) data definition language

d) high level language.

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iii) Cartesian product in relational algebra is

a) a unary operator b) a binary operator

c) a ternary operator d) not defined.

iv) DML is provided for

a) description of logical structure of database

b) addition of new structures in the database system

c) manipulation & processing of database

d) definition of physical structure of database

system.

v) In a relational model, relations are termed as

a) Tuples b) Attributes

c) Tables d) Rows.

vi) In case of entity integrity, the primary key may be

a) not Null b) Null

c) both Null & not Null d) any value.

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vii) In an E-R diagram an entity set is represented by a

a) rectangle b) ellipse

c) diamond box d) circle.

viii) Which of the following operations is used if we are

interested in only cetain columns of a table ?

a) PROJECTION b) SELECTION

c) UNION d) JOIN.

ix) Which of the following is a comparison operator in

SQL ?

a) = b) LIKE

c) BETWEEN d) All of these.

x) Using relational algebra the query that finds customers,

who have a balance of over 1000 is

a) Customer_name( balance > 1000 (Deposit) )

b) Customer_name( balance > 1000 (Deposit) )

c) Customer_name( balance > 1000 (Borrow) )

d) Customer_name( balance > 1000 (Borrow) ).

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GROUP – B( Short Answer Type Questions )Answer any three of the following. 3 5 = 15

2. Explain in brief 3-schema architecture of DBMS.

3. Explain with example super key, candidate key and primary

key.

4. What is cardinality ratio ? What is the difference between

procedural and non-procedural DML ? What is disjointness

constraint ? 1 + 2 + 2

5. Describe three layer architecture of DBMS.

6. Indicate the advantage of DBMS over conventional file

system.

GROUP – C( Long Answer Type Questions )Answer any three of the following. 3 15 = 45

7. a) What do you mean by integrity constraint ?

b) What is lossless decompostion ?

c) What do you mean by closure ?

d) Suppose that we decompose the schema,

R = ( A, B, C, D ) into ( A, B, C ) and ( A, D, E ).

Show that this decomposition is lossless decomposition,

if the following set F of FDs holds —

A BC, CD E, B D, E A. 2 + 2 + 2 + 9

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8. a) State two-phase commit protocol and discuss the

implications of a failure on the part of

i) the coordinator

ii) a participant, during each of the two phases.

b) Describe the wait-die and wound-wait protocols for

deadlock prevention.

c) Define three concurrency problems : dirty read, non-

repeatable read, phantoms.

d) Let T1, T2 and T3 be transactions that operate on the

same data items A, B and C. Let r1(A) mean that T1

reads A w1(A) means that T1 writes A and so on for T2

and T3.

Consider the following schedule :

S1 : r2(c), r2(B), w2(b), r3(B), r3(C), r1(A), w1(A), w3(B),

w3(C), r2(A), r1(B), w1(B), w2(A)

Is the schedule serializable ?

e) What are the roles of Analysis, Redo and Undo phases

in the recovery algorithm 'ARIES' ? 4 + 2 + 3 + 3 + 3

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9. a) When do we call a relation is in 3NF ?

b) Consider the relation assignment {worker_id,

building_id, startdate, name skilltype} and FDs are

{worker_id->name, (worker_id, building_id)->startdate}.

Is the relation in 2NF ? If not, then make it in 2NF.

c) Describe Boyce-Codd normal form with example.

d) What is Query Tree ? Why we need query tree ?

Consider the query "SELECT EMP_NAME FROM

EMPLOYEE, WORK_ON, PROJECT WHERE

PROJECT_NAME='ASSEMBLY' AND PRJ_NO='P1'AND

JPOIN_DATE='21-12-12'. Construct a query tree for

this query. 1 + 4 + 3 + ( 1 + 2 + 4 )

10. a) What is trnasacton ?

b) What is ACID property ?

c) Explain with example serial and serializable schedule.

d) What are the problems of concurrent execution of

transaction ?

e) Explain with the help of precedence graph the conflict

and non-conflict serializability. 1 + 3 + 4 + 3 + 4

6102 6


11. Write short notes on any three of the following : 3 5

a) Functional dependency

b) Dead lock

c) Transaction state diagram

d) B-tree

e) Data Dictionary.

6102 7 [ Turn over

6001 [ Turn over

Name : …………………………………………….……………… Roll No. : …………………………………………...…………….. Invigilator’s Signature : ………………………………………..

CS/B.TECH (CSE)/SEM-6/CS-601/2011

2011 COMPUTER NETWORKS

Time Allotted : 3 Hours Full Marks : 70

The figures in the margin indicate full marks. Candidates are required to give their answers in their own words

as far as practicable.

GROUP – A ( Multiple Choice Type Questions )

1. Choose the correct alternatives for any ten of the following :

10 × 1 = 10

i) The total number of links required to connect n devices using Mesh topology is

a) 2n b) n (n + 1)/2

c) n (n – 1)/2 d) n 2.

ii) Flow control is the responsibilities of the

a) Data link layer b) Transport layer

c) Both of these d) none of these.

iii) In selective repeat sliding window protocol, the receiver window size is

a) greater than one b) one

c) two d) none of these.


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iv) ICMP resides at the same layer as which of the following

protocols mentioned below ?

a) TCP b) UDP

c) IP d) ARP.

v) In HDLC inserts a 0 bit after ________ consequtive 1 bits

in the message data.

a) 4 b) 6

c) 5 d) 7.

vi) The Hamming code is used for

a) error detection b) error correction

c) error encapsulation d) both (a) and (b).

vii) Which channel access method is used in Ethernet

network ?

a) CSMA/CD b) Token bus

c) Token ring d) all of those.

viii) When a host knows its IP address but not its physical

address, it can use

a) RARP b) ICMP

c) ARP d) IGMP.

ix) Which of the following is a valid host for network 192.168.10.32/28 ?

a) 192.168.10.39 b) 192.168.10.47

c) 192.168.10.14 d) 192.168.10.54.


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x) Pure ALOHA has a maximum efficiency of

a) 18% b) 37%

c) 10% d) none of these.

xi) If user A wants to send a message to user B confidentially, the plain text is encrypted with the public key of

a) A b) B

c) the network d) Either A or B.

xii) A) DNS i) Name service

B) FTP ii) Rile sharing

C) NFS iii) File transfer

D) SMTP iv) Mail service.

Which of the following is the correct match ?

A B C D

a) (iv) (iii) (ii) (i)

b) (i) (ii) (iii) (iv)

c) (i) (iii) (ii) (iv)

d) (ii) (iv) (iii) (i).

GROUP – B

( Short Answer Type Questions )

Answer any three of the following. 3 × 5 = 15

2. a) How does Manchester encoding differ from differential

Manchester encoding ?


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b) Draw the following encoding scheme for the bit stream :

0001110101

i) NRZ-I

ii) Manchester coding

iii) Differential Manchester coding. 2 + 3

3. Suppose a system uses Stop and Wait protocol with

propagation delay 20ms. If the frame size is 160 bits and

band width is 4kbps then calculate channel utilization or

efficiency.

4. Applying CRC algorithm, determine the checksum and the

transmitted frame for the bit stream 11010111 and for the

generator polynomial x3 + x2 + 1.

5. What is Bit rate ? What is Baud rate ?

An analog signal carries 4 bits in each signal unit. If 1000

signal units are sent per second, find the baud rate and bit

rate. 1 + 1 + 3

6. a) What is the purpose of subnetting ? Find the netid and

the hostid of the following IP addresses.

i) 19.34.21.5

ii) 220.34.8.9

b) A network has subnet mask 255.255.255.224

Determine the maximum or number of Host in this

network.

Also determine the broadcast address of this network.

1 + 2 + 2


6001 5 [ Turn over

GROUP – C

( Long Answer Type Questions )

Answer any three of the following. 3 × 15 = 45

7. a) Suppose a system uses Go Back N protocol with window

size 3. If a sender wants to transmit 6 frames and every

4th frame is error then calculate how many number of

extra frames to be transmitted to the receiver.

b) Find the expressions for average delay and throughput

for both pure ALOHA and slotted ALOHA. Compare their

performances as well.

c) Why are medium access control techniques required ?

Discuss three popular medium access control

techniques in brief. 4 + 4 + (1 + 6)

8. a) A 10 bit data bit block 011101010111 is to be sent

using hamming code for error detection and correction.

Show how the receiver corrects an error that occurs in

6th bit position from righ.

b) Explain the utility of layered network architecture.

Compare ISO-OSI and TCP/IP models.

c) Differentiate circuit switching and packet switching.

6 + (2 + 4) + 3


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9. a) What is congestion ?

b) Why does congestion occur ?

c) Explain Leaky Bucket algorithm for congestion control.

d) State the basic difference between TCP and UDP.

e) Compare IPv4 and IPv6. 2 + 2 + 4 + 3 + 4

10. a) Distinguish between adapting routing and fixed routing.

Why is adaptive routing preferred over fixed routing ?

b) Differentiate between Link State and Distance Vector

routing algorithms.

c) How are 'iterative query resolution' and 'recursive query

resolution' different from each other in the context of

DNS ? Explain with example.

d) What do you understand dy data privacy ? How can

authentication, integrity and non-repudiation be

implemented by digital signature ? 4 + 3 + 4 + 4


6001 7 [ Turn over

11. Write short notes any three of the following 3 × 5

a) Firewall

b) NAT

c) VLAN

d) IEEE 802.11

e) ISDN

f) IPv6.

WBUT Computer Science Engineering6th Semester Previous Year Question

Paper

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