UGC NET CS 2018 July - II Question 54

Question 54

---

54. Normally user programs are prevented from handling I/O directly by I/O instructions in them. For CPUs having explicit I/O instructions, such I/O protection is ensured by having the I/O instructions privileged. In a CPU with memory mapped I/O, there is no explicit I/O instruction. Which one of the following is true for a CPU with memory mapped I/O ?

1. (1) I/O protection is ensured by operating system routines.
2. (2) I/O protection is ensured by a hardware trap.
3. (3) I/O protection is ensured during system configuration.
4. (4) I/O protection is not possible.

Answer: (1) I/O protection is ensured by operating system routines.

Previous	Next
UGC NET CS 2018 July - II Question 53	UGC NET CS 2018 July - II Question 55

UGC NET Computer Science July 2018 - II Question 53

Question 53

---

53. In a multi-user operating system, 30 requests are made to use a particular resource per hour, on an average. The probability that no requests are made in 40 minutes, when arrival pattern is a poisson distribution, is ______ .

1. (1) e^-15
2. (2) 1 - e^-15
3. (3) 1 - e^-20
4. (4) e^-20

Answer : (4) e^-20

Explanation Question 53

In 1 Hour = 30 Requests Sent
∴ In 60 minutes = 30 Requests Sent
So, in 40 minutes = (30 x 40) / 60 = 20 Requests Sent

Here 20 is Number of request Sent in 40 minutes.
Let λ is number of request in 40 minutes
∴ λ = 20

But according to given statement in question Actual requests are made in 40 minutes is ZERO.

Let x is actual requests in 40 minutes.
i.e. x = 0 (According to Question)

As arrival pattern is a poisson distribution,
So, Probablity ( x ) = ( e^-λ * λ^x ) / x !
∴ Probablity ( x = 0 ) = ( e^-20 * λ⁰ ) / 0!
∴ Probablity ( x = 0 ) = e^-20

So, option (4) is correct answer.

Previous	Next
UGC NET CS 2018 July - II Question 52	UGC NET CS 2018 July - II Question 54

UGC NET Computer Science July 2018 - II Question 52

Question 52

---

52. In a paged memory, the page hit ratio is 0.40. The time required to access a page in secondary memory is equal to 120 ns. The time required to access a page in primary memory is 15 ns. The average time required to access a page is ______ .

1. (1) 105
2. (2) 68
3. (3) 75
4. (4) 78

Answer : (4) 78

Explanation Question 52

PAGE HIT = page present in ram or main memory
PAGE MISS = page fault so page swapped from the secondary memory
because we look for a page in secondary memory when the page is not present in the main memory, therefore, we need to add main memory lookup time.

Average access time
= hit ratio * primary memory access time + (1 – hit ratio) * secondary memory access time
Average access time = 0.4 * 15 + 0.6 * 120
Average access time = 6 + 72
Average access time = 78.

So, option (4) is correct answer.

Previous	Next
UGC NET CS 2018 July - II Question 51	UGC NET CS 2018 July - II Question 53

UGC NET Computer Science July 2018 - II Question 51

Question 51

---

51. At a particular time of computation, the value of a counting semaphore is 10. Then 12 P operations and “x” V operations were performed on this semaphore. If the final value of semaphore is 7, x will be :

Options:

1. (1) 8
2. (2) 9
3. (3) 10
4. (4) 11

Answer : (2) 9

Explanation Question 51

Intially the value of a counting semaphore is 10 Now 12 P operation are performed.

Now counting semaphore value = -2

“x” V operations were performed on this semaphore

Final value of counting semaphore = 7
∴ ( “x” V operations + current counting semaphore value (-2) ) = 7
∴ x + (-2) = 7
∴ x = 7 + 2
∴ x = 9.

So, option (2) is correct answer.

Previous	Next
UGC NET CS 2018 July - II Question 50	UGC NET CS 2018 July - II Question 52

UGC NET CS 2018 July - II Question 97

Question 97

---

97. Match the items in List - I and List - II :

List - I	List -II
(a) Interrupts which can be delayed when a much highest priority interrupt has occurred	(i) Normal
(b) Unplanned interrupts which occur while executing a program	(ii) Synchronous
(c) Source of interrupt is in phase with the system clock	(iii) Maskable
	(iv) Exception

Code :

	(a)	(b)	(c)
(1)	(ii)	(i)	(iv)
(2)	(ii)	(iv)	(iii)
(3)	(iii)	(i)	(ii)
(4)	(iii)	(iv)	(ii)

Options:

1. (1)
2. (2)
3. (3)
4. (4)

Answer : (4)

Explanation Question 97

• (a) Interrupts which can be delayed when a much highest priority interrupt has occurred → (iii) Maskable
• (b) Unplanned interrupts which occur while executing a program → (iv) Exception
• (c) Source of interrupt is in phase with the system clock → (ii) Synchronous

→ Maskable Interrupt: The hardware interrupts which can be delayed when a much highest priority interrupt has occurred to the processor.

→ Exception: unplanned interrupts while executing a program is called Exception. For example: while executing a program if we got a value which should be divided by zero is called a exception

Reference : Types of Interrupts

→ Synchronous interrupt will happen every time an instruction executes (with a given program state)
Examples of Synchronous interrupt:
– Divide by zero
– System call
– Bad pointer dereference

Reference 2 : Two types of interrupts - Synchronous / Asynchronous

Previous	Next
UGC NET CS 2018 July - II Question 96	UGC NET CS 2018 July - II Question 98

UGC NET CS 2018 July - II Question 95

Question 95

---

95. The hexadecimal equivalent of the binary integer number 110101101 is :

1. (1) D24
2. (2) 1BD
3. (3) 1AE
4. (4) 1AD

Answer : (3) 1AE

Explanation Question 95

Answer: 3

Group the given number in subgroup of 4 from right and assign alphabet when it exceeds 1001:
1010 – A
1011 – B
1100 – C
1101 – D
1110 – E
1111 – F
Given number is 110101101:
1101 – D
1010 – A
1 – 1

Hexadecimal equivalent iss 1AD.
So, option (D) is correct.

Previous	Next
UGC NET CS 2018 July - II Question 94	UGC NET CS 2018 July - II Question 96

UGC NET CS 2018 July - II Question 90

Question 90

---

Which of the following statements is true ?

1. (1) (Z, ≤ ) is not totally ordered
2. (2) The set inclusion relation ⊆ is a partial ordering on the power set of a set S
3. (3) (Z, ≠ ) is a poset
4. (4) The directed graph is not a partial order
   

   

   Diagram for option (4) The directed graph is not a partial order

Answer : (2) The set inclusion relation ⊆ is a partial ordering on the power set of a set S

Explanation Question 90

Options (1) - FALSE
(Z, ≤ ) is not totally ordered
Z = (..., -3, -2, -1, 0, 1, 2, 3, ...}
Show that “less than or equal” relation
is a partial ordering on the set of integers.
– a<=a for every integer a (reflexive)
– a<=b, b<=a, then a=b (anti-symmetric)
– a<=b, b<=c, then a<=c (transitive)
Thus <= is a partial ordering on the set of
integers
(Z,<=) is a poset.

To prove that Z is Totally Ordered Set:
If (S,R) is a poset and every two
elements of S are comparable, S is called
a totally ordered set or linearly ordered
set.

Comparable: The elements a and b of a poset (Z, ≤ )
are comparable, if either aRb or bRa holds.

Option 2: - TRUE
The set inclusion relation ⊆ is a partial ordering on the power set of a set S (TRUE)
let set S = {a,b}
P(S) = {{a} , {b} ,{a,b} , Φ}

Show that  relation (S,⊆) is a partial ordering on the set of integers.
Take any two element from S, lets say s1 and s2
– s1⊆s1 for every element s1 (reflexive)
– s1⊆s2, s2⊆s1, then s1==s2 (anti-symmetric)
– s1⊆s2, s2⊆s3, then s1⊆s3 (transitive)
Thus ⊆ is a partial ordering on the power set of a set S
(S,⊆) is a poset.

Options 3: - FALSE
(Z,≠) is a poset?
Show that (Z,≠) is a partial ordering on the set of integers.
Take any two integers, then
– aRa -> a≠a for every integer a (not reflexive)
Reflexive Relation doesn't satisfy.
So, (Z,≠) is not a poset.

Options 4: - FALSE
Relation set for the directed graph is D={(a,a),(a,b),(b,b)}
Reflecxive,transitive property holds for the elements in the set.
Anti-symattric -> if R(a, b) with a ≠ b, then R(b, a) must not hold, so, Anti-symattric also holds.

References:
Partial Orderings - http://cse.iitkgp.ac.in/~debdeep/courses_iitkgp/FOC/slidespdf/POS.pdf
Partially ordered set - https://en.wikipedia.org/wiki/Partially_ordered_set
Total order - https://en.wikipedia.org/wiki/Total_order

Previous	Next
UGC NET CS 2018 July - II Question 89	UGC NET CS 2018 July - II Question 91

UGC NET CS 2018 July - II Question 77

Question 77

---

77. Consider the following English sentence :
"Agra and Gwalior are both in India".
A student has written a logical sentence for the above English sentence in First-Order Logic using predicate In(x, y), which means x is in y, as follows :
In(Agra, India) ∨ In(Gwalior, India)
Which one of the following is correct with respect to the above logical sentence ?

Options:

1. (1) It is syntactically valid but does not express the meaning of the English sentence.
2. (2) It is syntactically valid and expresses the meaning of the English sentence also.
3. (3) It is syntactically invalid but expresses the meaning of the English sentence.
4. (4) It is syntactically invalid and does not express the meaning of the English sentence.

Answer : (1) It is syntactically valid but does not express the meaning of the English sentence.

Explanation Question 77

Predicate In(Agra, India) means Agra is in india
Predicate In(Gwalior, India) means Gwalior is in india

According to the given english statement "Agra and Gwalior are both in India", both Predicate "In(Agra,India)" and "In(Gwalior,India)" should be true

Therefore use of conjunction as connector requires between both predicates "In(Agra, India) ∧ In(Gwalior, India)".

But given that In(Agra, India) ∨ In(Gwalior, India), in this it uses connector "∨". So, the entire gives the meaning of Either Agra is in india or Gwalior is in india.

So, Logic is not equivalent for given English sentence and given First-Order Logic.
Given predicate "In(Agra, India) ∨ In(Gwalior, India)" is syntactically correct but not represent the given english statement.

So, option 1 is correct answer

Previous	Next
UGC NET CS 2018 July - II Question 76	UGC NET CS 2018 July - II Question 78

UGC NET Computer Science July 2018 - II | Question 76

Question 76

---

76. Consider the following statements :
(a) False ⊨ True
(b) If α ⊨ (β ∧ γ) then α ⊨ β and α ⊨ γ.
Which of the following is correct with respect to the above statements ?

1. (1) Both statement (a) and statement (b) are false.
2. (2) Statement (a) is true but statement (b) is false.
3. (3) Statement (a) is false but statement (b) is true.
4. (4) Both statement (a) and statement (b) are true.

Answer : (4) Both statement (a) and statement (b) are true.

Explanation Question 76

• Statement (a) "False ⊨ True" is TRUE
  A ⊨ B means "A" logically entails "B" if and only if the sentence A ⇒ B is valid.
  We need to prove that False ⇒ True is valid.
  ∴ False ⇒ True is always true
  because we know : (a ⇒ b) ≡ (¬a ∨ b) So, False ⇒ True is equivalent to ( ¬Flase ∨ True ) which is always true.
   
  
• Statement (b) "if α ⊨ (β ∧ γ) then α ⊨ β and α ⊨ γ" is TRUE
  by constructing below truth table you will find out that
  " α ⊨ β and α ⊨ γ " are true for all the cases for which "α ⊨ (β and γ)" is true
   
  

  α	β	γ	(β ∧ γ)	α ⊨ (β ∧ γ)	α ⊨ β	α ⊨ γ
  				¬ α ∨ (β ∧ γ)	¬ α ∨ β	¬ α ∨ γ
  0	0	0	0	1	1	1
  0	0	1	0	1	1	1
  0	1	0	0	1	1	1
  0	1	1	1	1	1	1
  1	0	0	0	0	0	0
  1	0	1	0	0	0	1
  1	1	0	0	0	1	0
  1	1	1	1	1	1	1

Definition of Logical Entailment
A set of sentences (called premises) logically entails a sentence (called a conclusion) if and only if every truth assignment that satisfies the premises also satisfies the conclusion.

Example of Logical Entailment:
“KB logically entails S” if all the models that evaluate KB to True also evaluate S to True.
Denoted by: KB ⊨ S

Reference : Logical Entailment

Reference 1 : Realm world example of Logical Entailment

Reference 2 : https://www.ics.uci.edu/~welling/teaching/271fall09/HW6_sol.pdf#page=8

Previous	Next
UGC NET CS 2018 July - II Question 75	UGC NET CS 2018 July - II Question 77

UGC NET CS 2018 July - II Question 94

Question 94

---

94. What does the following logic diagram represent ?

Flip-Flop Logic diagram

Options:

1. 1. Synchronous Counter
2. 2. Ripple Counter
3. 3. Combinational Circuit
4. 4. Mod 2 Counter

Answer : 2. Ripple Counter

Explanation Question 94

Ripple Counter : Ripple counter is an Asynchronous counter. It got its name because the clock pulse ripples through the circuit. An n-MOD ripple counter contains n number of flip-flops and the circuit can count up to 2 ⁿ values before it resets itself to the initial value.

Given Flip-Flop Logic diagram represents the Ripple counter.

So, option 2 is correct answer

Reference : A Brief about Ripple Counter with Circuit and Timing Diagrams

Previous	Next
UGC NET CS 2018 July - II Question 93	UGC NET CS 2018 July - II Question 95

UGC NET Computer Science July 2018 - II Question 91

Question 91

---

91. CMOS is a Computer Chip on the motherboard, which is :

Options:

1. (1) RAM
2. (2) ROM
3. (3) EPROM
4. (4) Auxillary storage

Answer : (1) RAM

Explanation Question 91

Complementary metal-oxide Semiconductor(CMOS) is a random access memory which stores computer start up information which is used by BIOS. CMOS memory in a computer is a type of non-volatile RAM (NVRAM) that stores BIOS settings and date/time information.

So, Option 1 is correct answer.

Reference 1 : CMOS Applications and Advantages

Reference 2 : CMOS Working Principle and Applications

Previous	Next
UGC NET CS 2018 July - II Question 90	UGC NET CS 2018 July - II Question 92

UGC NET Computer Science 2018 July - II Question 80

Question 80

---

80. Consider the set of all possible five-card poker hands dealt fairly from a standard deck of fifty-two cards. How many atomic events are there in the joint probability distribution ?

Options:

1. 1 2, 598, 960
2. 2 3, 468, 960
3. 3 3, 958, 590
4. 4 2, 645, 590

Answer : (1) 2, 598, 960

Explanation Question 80

Number of atomic events are there in the joint probability distributionof 5 cards hand from a 52 deck of cards is calculated as shown below:

Total number of combinations possible to have a set of 5 cards from 52,

Total atomic events or count = ⁵²C₅
= 52!/5! * (52-5)!
= 52!/5! * 47!
= (48 x 49 x 50 x 51 x 52)/5!
= 311875200/120
= 2598960

So, Option 1 is correct answer.

Previous	Next
UGC NET CS 2018 July - II Question 79	UGC NET CS 2018 July - II Question 81

UGC NET CS 2018 July - II Question 96

Question 96

---

96. Perform the following operation for the binary equivalent of the decimal numbers
(−14)₁₀+(−15)₁₀ The solution in 8-bit representation is :

Options:

1. (1) 11100011
2. (2) 00011101
3. (3) 10011101
4. (4) 11110011

Answer : (1) 11100011

Explanation Question 96

(−14)₁₀ + (−15)₁₀ = (-29)₁₀

Value of 29 in binary is 00011101

To get a binary value of -29:

1. We need to take 1’s complement of 00011101 → 11100010
2. Then add 1 to it. i.e. 11100011.

So, option (A) is the correct answer.

Previous	Next
UGC NET CS 2018 July - II Question 95	UGC NET CS 2018 July - II Question 97

UGC NET CS 2018 July - II Question 59

Question 59

---

59. Consider the following three processes with the arrival time and CPU burst time given in milliseconds :

Process	Arrival Time	Burst Time
P1	0	7
P2	1	4
P3	2	8

The Gantt Chart for preemptive SJF scheduling algorithm is _________.

Options:

1. (1)
2. (2)
3. (3)
4. (4)

Answer : (2)

Explanation Question 59

Question asks for Gantt Chart for preemptive SJF

Option (1) is Not preemptive.
P1 continues execution without being preempted when sorter process P2 with Burst time 4 comes.

Option (2) is Preemptive SJF.
Here, P1 executes for 1 second and then preempted by P2 which executes for 4 seconds. Then P1 finishes its remaining execution  followed by execution of P3.

Option (3) is Not preemptive.
Not pre-emptive as P1 continues execution without being preempted when sorter process P2 with Burst time 4 comes. Each of the processes carries on execution without being preempted.

Option (4) is Preemptive but P2 starts execution even before it's arrival time 1.

So, Option (2) is correct answer. 

Previous	Next
UGC NET CS 2018 July - II Question 58	UGC NET CS 2018 July - II Question 60

UGC NET CS 2018 July - II Question 75

Question 75

---

75. Consider a vocabulary with only four propositions A, B, C and D. How many models are there for the following sentence ?
B v C

Options:

1. (1) 10
2. (2) 12
3. (3) 15
4. (4) 16

Answer : (2) 12

Explanation Question 75

We know there are total 2⁴ = 16 cases.
As shown in below truth table, it won't satisfy the condition when B = C = 0.

A	B	C	D	B v C
0	0	0	0	0
0	0	0	1	0
0	0	1	0	1
0	0	1	1	1
0	1	0	0	1
0	1	0	1	1
0	1	1	0	1
0	1	1	1	1
1	0	0	0	0
1	0	0	1	0
1	0	1	0	1
1	0	1	1	1
1	1	0	0	1
1	1	0	1	1
1	1	1	0	1
1	1	1	1	1

So, from the given sentence false(0) occurs only if B and C are false(0) which occurs 4 times.
Required number of models = 16 - 4 = 12.

Hence, Option (2) is correct answer.

Previous	Next
UGC NET CS 2018 July - II Question 74	UGC NET CS 2018 July - II Question 76

UGC NET CS 2018 July - II Question 64

Question 64

---

64. Relations produced from E - R Model will always be in ________.

Options:

1. (1) 1 NF
2. (2) 2 NF
3. (3) 3 NF
4. (4) 4 NF

Answer : (3) 3 NF

Explanation Question 64

Option (3) is correct answer.

Previous	Next
UGC NET CS 2018 July - II Question 63	UGC NET CS 2018 July - II Question 65

UGC NET CS 2018 July - II Question 84

Question 84

---

84. Digital data received from a sensor can fill up 0 to 32 buffers. Let the sample space be S={0, 1, 2, .........., 32} where the sample j denote that j of the buffers are full and
p(i) = (1 / 561) (33 - i). Let A denote the event that the even number of buffers are full. Then p(A) is :

Options:

1. (1) 0.515
2. (2) 0.785
3. (3) 0.758
4. (4) 0.485

Answer : (1) 0.515

Explanation Question 84

Probability of i th buffer getting full = p(i) = 1 / 562 (33 − i)
Probability of all even number of buffers are full is P(A)

P(A) = Σ _{i = 0, 2, 4, .., 32} P(i) = Σ _{i = 0, 1, 2, .., 16} P(2i)

We are going find the values of P(0), P(2), P(4), P(6) .... P(16).
P(0) = 1 / 562 (33 - 0)
P(2) = 1 / 562 (33 - 2)
...
P(16) = 1 / 562 (33 - 32)

The probability of all even number of buffers are full is P(A) which is equal to
P(0) + P(2) + P(4) + P(6) + .... P(16).
P(A) = 1 / 562(33 + 31 + 29 + 27 + .... + 1)
P(A) =(1 / 562) * 289
= 0.51423 = 0.515

So, Option (1) is correct answer.

Previous	Next
UGC NET CS 2018 July - II Question 83	UGC NET CS 2018 July - II Question 85

UGC NET CS 2018 July - II Question 100

100. In 8085 microprocessor, what is the output of following program ?
LDA 8000H
MVI B, 30H
ADD B
STA 8001H

(1) Read a number from input port and store it in memory
(2) Read a number from input device with address 8000H and store it in memory at location 8001H
(3) Read a number from memory at location 8000H and store it in memory location 8001H
(4) Load A with data from input device with address 8000H and display it on the output
device with address 8001H

Answer: 3

Previous	Next
UGC NET CS 2018 July - II Question 99	UGC NET CS 2018 July - II Question 101

UGC NET CS 2018 July - II Question 99

99. Simplify the following using K-map :
F (A, B, C, D) = Σ (0, 1, 2, 8, 9, 12, 13)
d (A, B, C, D) = Σ (10, 11, 14, 15)
d stands for don’t care condition.

(1) A+B D + BC (2) A+B D + B C
(3) A+B C (4) A+B C+B D

Answer: 3

Previous	Next
UGC NET CS 2018 July - II Question 98	UGC NET CS 2018 July - II Question 100

UGC NET CS 2018 July - II Question 98

98. Which of the following mapping is not used for mapping process in cache memory ?

(1) Associative mapping (2) Direct mapping
(3) Set-Associative mapping (4) Segmented - page mapping

Answer: 3

Previous	Next
UGC NET CS 2018 July - II Question 97	UGC NET CS 2018 July - II Question 99

UGC NET CS 2018 July - II Question 93

93. Match the terms in List - I with the options given in List - II : List - I List - II
(a) Decoder (i) 1 line to 2n lines
(b) Multiplexer (ii) n lines to 2n lines
(c) De multiplexer (iii) 2n lines to 1 line
(iv) 2n lines to 2n−1 lines

Code :
(a) (b) (c)
(1) (ii) (i) (iii)
(2) (ii) (iii) (i)
(3) (ii) (i) (iv)
(4) (iv) (ii) (i)

Answer: 3

Previous	Next
UGC NET CS 2018 July - II Question 92	UGC NET CS 2018 July - II Question 94

UGC NET CS 2018 July - II Question 92

92. In RS flip-flop, the output of the flip-flop at time (t+1) is same as the output at time t, after
the occurance of a clock pulse if :

(1) S=R=1 (2) S=0, R=1
(3) S=1, R=0 (4) S=R=0

Answer: 3

Previous	Next
UGC NET CS 2018 July - II Question 91	UGC NET CS 2018 July - II Question 93

UGC NET CS 2018 July - II Question 89

89. Which of the following is an equivalence relation on the set of all functions from Z to
Z ?

(1) { (f, g) ? f (x)−g (x)=1 x e Z }
(2) { (f, g) ? f (0)=g (0) or f (1)=g (1) }
(3) { (f, g) ? f (0)=g (1) and f (1)=g (0) }
(4) { (f, g) ? f (x)−g (x)=k for some k e Z }

Answer: 4

Previous	Next
UGC NET CS 2018 July - II Question 88	UGC NET CS 2018 July - II Question 90

UGC NET CS 2018 July - II Question 88

88. Which of the relations on {0, 1, 2, 3} is an equivalence relation ?

(1) { (0, 0) (0, 2) (2, 0) (2, 2) (2, 3) (3, 2) (3, 3) }
(2) { (0, 0) (1, 1) (2, 2) (3, 3) }
(3) { (0, 0) (0, 1) (0, 2) (1, 0) (1, 1) (1, 2) (2, 0) }
(4) { (0, 0) (0, 2) (2, 3) (1, 1) (2, 2) }

Answer: 2

Previous	Next
UGC NET CS 2018 July - II Question 87	UGC NET CS 2018 July - II Question 89

UGC NET CS 2018 July - II Question 87

87. Match the following in List - I and List - II, for a function f :
List - I List - II
(a) x y (f (x)=f (y) → x=y) (i) Constant
(b) y ∃ x (f (x)=y) (ii) Injective
(c) x f (x)=k (iii) Surjective

Code :
(a) (b) (c)
(1) (i) (ii) (iii)
(2) (iii) (ii) (i)
(3) (ii) (i) (iii)
(4) (ii) (iii) (i)

Answer: 4

Previous	Next
UGC NET CS 2018 July - II Question 86	UGC NET CS 2018 July - II Question 88

UGC NET CS 2018 July - II Question 86

86. If Ai={−i, ... −2,−1, 0, 1, 2, . . . . . i}
then i
i 1
A

=
is :

(1) Z (2) Q (3) R (4) C

Answer: 1

Previous	Next
UGC NET CS 2018 July - II Question 85	UGC NET CS 2018 July - II Question 87

UGC NET CS 2018 July - II Question 85

85. The equivalence of

¬ ∃ x Q (x) is :
(1) ∃ x ¬ Q (x) (2) x ¬ Q (x) (3) ¬ ∃ x ¬ Q (x) (4) x Q (x)

Answer: 2

Previous	Next
UGC NET CS 2018 July - II Question 84	UGC NET CS 2018 July - II Question 86

UGC NET CS 2018 July - II Question 83

83. The following LPP
Maximize z=100x1+2x2+5x3
Subject to
14x1+x2−6x3+3x4=7
32x1+x2−12x3≤10
3x1−x2−x3≤0
x1, x2, x3, x4/0
has

(1) Solution : x1=100, x2=0, x3=0 (2) Unbounded solution
(3) No solution (4) Solution : x1=50, x2=70, x3=60

Answer: 2

Previous	Next
UGC NET CS 2018 July - II Question 82	UGC NET CS 2018 July - II Question 84

UGC NET CS 2018 July - II Question 82

82. Which of the following statements is false about convex minimization problem ?

(1) If a local minimum exists, then it is a global minimum
(2) The set of all global minima is convex set
(3) The set of all global minima is concave set
(4) For each strictly convex function, if the function has a minimum, then the minimum is
unique

Answer: 3

Previous	Next
UGC NET CS 2018 July - II Question 81	UGC NET CS 2018 July - II Question 83

UGC NET CS 2018 July - II Question 81

81. E is the number of edges in the graph and f is maximum flow in the graph. When the
capacities are integers, the runtime of Ford-Fulberson algorithm is bounded by :

(1) O (E∗f) (2) O (E2∗f)
(3) O (E∗f2) (4) O (E2∗f2)

Answer:

Previous	Next
UGC NET CS 2018 July - II Question 80	UGC NET CS 2018 July - II Question 82

UGC NET CS 2018 July - II Question 79

79. A knowledge base contains just one sentence, ∃x AsHighAs (x, Everest). Consider the
following two sentences obtained after applying existential instantiation.
(a) AsHighAs (Everest, Everest)
(b) AsHighAs (Kilimanjaro, Everest)
Which of the following is correct with respect to the above sentences ?

(1) Both sentence (a) and sentence (b) are sound conclusions.
(2) Both sentence (a) and sentence (b) are unsound conclusions.
(3) Sentence (a) is sound but sentence (b) is unsound.
(4) Sentence (a) is unsound but sentence (b) is sound.

Answer: 4

Previous	Next
UGC NET CS 2018 July - II Question 78	UGC NET CS 2018 July - II Question 80

UGC NET CS 2018 July - II Question 78

78. Consider the following two sentences :
(a) The planning graph data structure can be used to give a better heuristic for a planning
problem.
(b) Dropping negative effects from every action schema in a planning problem results in a
relaxed problem.
Which of the following is correct with respect to the above sentences ?

(1) Both sentence (a) and sentence (b) are false.
(2) Both sentence (a) and sentence (b) are true.
(3) Sentence (a) is true but sentence (b) is false.
(4) Sentence (a) is false but sentence (b) is true.
J-08718 !J-08718-PAPER-II! 19 Paper-II

Answer: 2

Previous	Next
UGC NET CS 2018 July - II Question 77	UGC NET CS 2018 July - II Question 79

UGC NET CS 2018 July - II Question 74

74. Consider following sentences regarding A*, an informed search strategy in Artificial
Intelligence (AI).

(a) A* expands all nodes with f(n) < C*.
(b) A* expands no nodes with f(n) /C*.
(c) Pruning is integral to A*.
Here, C* is the cost of the optimal solution path.
Which of the following is correct with respect to the above statements ?
(1) Both statement (a) and statement (b) are true.
(2) Both statement (a) and statement (c) are true.
(3) Both statement (b) and statement (c) are true.
(4) All the statements (a), (b) and (c) are true.

Answer: 2

Previous	Next
UGC NET CS 2018 July - II Question 73	UGC NET CS 2018 July - II Question 75

UGC NET CS 2018 July - II Question 73

73. In heuristic search algorithms in Artificial Intelligence (AI), if a collection of admissible
heuristics h1.......hm is available for a problem and none of them dominates any of the others,
which should we choose ?

(1) h(n)=max{h1(n),....,hm(n)}
(2) h(n)=min{h1(n),....,hm(n)}
(3) h(n)=avg{h1(n),....,hm(n)}
(4) h(n)=sum{h1(n),....,hm(n)}

Answer: 1

Previous	Next
UGC NET CS 2018 July - II Question 72	UGC NET CS 2018 July - II Question 74

UGC NET CS 2018 July - II Question 72

72. In Artificial Intelligence (AI), a simple reflex agent selects actions on the basis of_________.

(1) current percept, completely ignoring rest of the percept history.
(2) rest of the percept history, completely ignoring current percept.
(3) both current percept and complete percept history.
(4) both current percept and just previous percept.

Answer: 3

UGC NET CS 2018 July - II Question 71

71. In Artificial Intelligence (AI), an environment is uncertain if it is ________.

(1) Not fully observable and not deterministic
(2) Not fully observable or not deterministic
(3) Fully observable but not deterministic
(4) Not fully observable but deterministic

Answer: 3

UGC NET CS 2018 July - II Question 70

70. Consider a hash table of size seven, with starting index zero, and a hash function (7x+3)
mod 4. Assuming the hash table is initially empty, which of the following is the contents of
the table when the sequence 1, 3, 8, 10 is inserted into the table using closed hashing ? Here
“__” denotes an empty location in the table.

(1) 3, 10, 1, 8, __ , __ , __
(2) 1, 3, 8, 10, __ , __ , __
(3) 1, __ , 3, __ , 8, __ , 10
(4) 3, 10, __ , __ , 8, __ , __

Answer: 1

Previous	Next
UGC NET CS 2018 July - II Question 69	UGC NET CS 2018 July - II Question 71

UGC NET CS 2018 July - II Question 69

69. Let R1(a, b, c) and R2(x, y, z) be two relations in which a is the foreign key of R1 that refers to
the primary key of R2. Consider following four options.

(a) Insert into R1 (b) Insert into R2
(c) Delete from R1 (d) Delete from R2
Which of the following is correct about the referential integrity constraint with respect to
above ?
(1) Operations (a) and (b) will cause violation.
(2) Operations (b) and (c) will cause violation.
(3) Operations (c) and (d) will cause violation.
(4) Operations (d) and (a) will cause violation.

Answer: 4

Previous	Next
UGC NET CS 2018 July - II Question 68	UGC NET CS 2018 July - II Question 70

UGC NET CS 2018 July - II Question 68

68. Database systems that store each relation in a separate operating system file may use the
operating system’s authorization scheme, instead of defining a special scheme themselves.
In this case, which of the following is false ?

(1) The administrator enjoys more control on the grant option.
(2) It is difficult to differentiate among the update, delete and insert authorizations.
(3) Cannot store more than one relation in a file.
(4) Operations on the database are speeded up as the authorization procedure is carried
out at the operating system level.

Answer: 1

Previous	Next
UGC NET CS 2018 July - II Question 67	UGC NET CS 2018 July - II Question 69

UGC NET CS 2018 July - II Question 67

67. A many-to-one relationship exists between entity sets r1 and r2. How will it be represented
using functional depedencies if Pk(r) denotes the primary key attribute of relation r ?

(1) Pk(r1) → Pk(r2)
(2) Pk(r2) → Pk(r1)
(3) Pk(r2) → Pk(r1) and Pk(r1) → Pk(r2)
(4) Pk(r2) → Pk(r1) or Pk(r1) → Pk(r2)

Answer: 1

Previous	Next
UGC NET CS 2018 July - II Question 66	UGC NET CS 2018 July - II Question 68

UGC NET CS 2018 July - II Question 66

66. For a database relation R(a, b, c, d) where the domains of a, b, c and d include only atomic
values, and only the following functional dependencies and those that can be inferred from
them hold :

a → c
b → d
The relation is in _________.
(1) First normal form but not in second normal form
(2) Second normal form but not in third normal form
(3) Third normal form
(4) BCNF

Answer: 3

UGC NET CS 2018 July - II Question 65

65. Consider the following schedules involving two transactions.
S1 : r1(X) ; r1(Y) ; r2(X) ; r2(Y) ; w2(Y) ; w1(X)
S2 : r1(X) ; r2(X) ; r2(Y) ; w2(Y) ; r1(Y) ; w1(X)
Which one of the following statements is correct with respect to above ?

(1) Both S1 and S2 are conflict serializable.
(2) Both S1 and S2 are not conflict serializable.
(3) S1 is conflict serializable and S2 is not conflict serializable.
(4) S1 is not conflict serializable and S2 is conflict serializable.

Answer: 4

Previous	Next
UGC NET CS 2018 July - II Question 64	UGC NET CS 2018 July - II Question 66

UGC NET CS 2018 July - II Question 63

63. In a Hierachical database, a hashing function is used to locate the ________.

(1) Collision (2) Root
(3) Foreign Key (4) Records

Answer: 3

UGC NET CS 2018 July - II Question 62

62. Consider a relation book (title, price) which contains the titles and prices of different books.
Assuming that no two books have the same price, what does the following SQL query list ?

Select title
from book as B
where (select count (*)
from book as T
where T.price > B.price) < 7
(1) Titles of the six most expensive books.
(2) Title of the sixth most expensive books.
(3) Titles of the seven most expensive books.
(4) Title of the seventh most expensive books.

Answer: 3

UGC NET CS 2018 July - II Question 61

61. In RDBMS, which type of Join returns all rows that satisfy the join condition ?

(1) Inner Join
(2) Outer Join
(3) Semi Join
(4) Anti Join

Explanation:
Answer: (1) Inner Join

INNER JOIN:
The INNER JOIN of two or more tables returns only those rows that satisfy the join condition

OUTER JOIN:
An outer join returns all rows that satisfy the join condition and rows not matching for the table on the right/left/both side of join(RIGHT JOIN/ LEFT JOIN/FULL JOIN respectively).

Previous	Next
UGC NET CS 2018 July - II Question 60	UGC NET CS 2018 July - II Question 62

UGC NET CS 2018 July - II Question 60

60. In which of the following scheduling criteria, context switching will never take place ?

(1) ROUND ROBIN
(2) Preemptive SJF
(3) Non-preemptive SJF
(4) Preemptive priority

Explanation:

Answer: (3) Non-preemptive SJF

Non-preemptive algorithms doesn't allow to switch the process until it is completed.
In case of Non-preemptive algorithms context switching will never take place.
So, option (C) is correct answer.

Previous	Next
UGC NET CS 2018 July - II Question 59	UGC NET CS 2018 July - II Question 61

UGC NET CS 2018 July - II Question 58

58. Consider a virtual page reference string 1, 2, 3, 2, 4, 2, 5, 2, 3, 4. Suppose LRU page replacement
algorithm is implemented with 3 page frames in main memory. Then the number of page
faults are_________.

(1) 5 (2) 7 (3) 9 (4) 10

Answer: 3

UGC NET CS 2018 July - II Question 57

57. Page information in memory is also called as Page Table. The essential contents in each entry
of a page table is/are _________.

(1) Page Access information
(2) Virtual Page number
(3) Page Frame number
(4) Both virtual page number and Page Frame Number

Answer: 3

UGC NET CS 2018 July - II Question 56

56. Which of the following statements are true ?

(a) External Fragmentation exists when there is enough total memory space to satisfy a
request but the available space is contiguous.
(b) Memory Fragmentation can be internal as well as external.
(c) One solution to external Fragmentation is compaction.
Code :
(1) (a) and (b) only (2) (a) and (c) only
(3) (b) and (c) only (4) (a), (b) and (c)

Answer: 3

UGC NET CS 2018 July - II Question 55

55. Which UNIX/Linux command is used to make all files and sub-directories in the directory
“progs” executable by all users ?

(1) chmod− R a+x progs (2) chmod −R 222 progs
(3) chmod−X a+x progs (4) chmod −X 222 progs

Answer: 3

UGC NET Computer Science July 2018 - II Question 50

Question 50

---

Encrypt the Message “HELLO MY DEARZ” using Transposition Cipher with

Key

{

Plain Text    2 4 1 3 Cipher Text    1 2 3 4

Options:

1. (1) HLLEO YM AEDRZ
2. (2) EHOLL ZYM RAED
3. (3) ELHL MDOY AZER
4. (4) ELHL DOMY ZAER

Answer: (3) ELHL MDOY AZER

Explanation Question 50

Given:
In question encryption of given message using Transposition Cipher with Given message is “HELLO MY DEARZ”
Key - Plain Text -> 2 4 1 3
Key - Cipher Text ->1 2 3 4

Solution:
Step-1: According to key size divide number of character into blocks. Here, key size is 4. So, character block size is 4.
Step-2: Remove the spaces in the given message and write characters in sequential order. Now arrange then in group of 4 as shown in below matrix.

Key
1	2	3	4
H	E	L	L
O	M	Y	D
E	A	R	Z

Step-3: Sort column as per given Plain key as shown in below matrix.

Key
2	4	1	3
E	L	H	L
M	D	O	Y
A	Z	E	R

Read the matrix horizontally one by one row.

Encrypted message will be ELHL MDOY AZER.

So, option (3) is correct.

Previous	Next
UGC NET CS 2018 July - II Question 49	UGC NET CS 2018 July - II Question 51

UGC NET Computer Science July 2018 - II Question 49

Question 49

---

49. To guarantee correction of upto t errors, the minimum Hamming distance dmin in a block code must be ________.

1. (1) t+1
2. (2) t-2
3. (3) 2t-1
4. (4) 2t+1

Answer : (4) 2t+1

Explanation Question 49

To guarantee correction of up to t errors in all cases, the minimum Hamming distance in a block code must be dmin = 2t + 1.

Reference : Minimum Hamming Distance for Error Correction

Previous	Next
UGC NET CS 2018 July - II Question 48	UGC NET CS 2018 July - II Question 50

UGC NET Computer Science July 2018 - II Question 48

Question 48

---

Decrypt the message “WTAAD” using the Caesar Cipher with key = 15.

1. (1) LIPPS
2. (2) HELLO
3. (3) OLLEH
4. (4) DAATW

Answer : (2) HELLO

Explanation Question 48

Caesar Cipher Algorithm Mathematical Description:
First we translate all of our characters to numbers, 'a'=0, 'b'=1, 'c'=2, ... , 'z'=25.
We can now represent the Caesar cipher encryption function, e(x), where x is the character we are encrypting, as:
e(x)=(x+k) (mod 26)

Where k is the key (the shift) applied to each letter.
After applying this function the result is a number which must then be translated back into a letter.
The decryption function is :
d(x)=(x-k) (mod 26)

Solution:

Remember alphabet ordering:
Only remember the alphabets that occur at multiplication of 5:
1 st alphabet -> A  (1)
2 nd alphabet -> E (5)
3 rd alphabet -> J  (10)
4 th alphabet -> O (15)
5 th alphabet -> T (20)
6 th alphabet -> Y (25)

Need to remember word EJOTY
for our case number numbering is E- 4, J-9, O-14, T-19 Y-24

Position of our alphabets:
W -> T+3 -> (19+3) = 22
T -> 19
A -> 1
D -> 3

Decryption of given alphabets:
W -> (22 -15) (mod 26) = 7 ->H
T -> (19 -15) (mod 26) = 4  -> E
A -> (1-15) (mod 26) = -14 +26 -> L
A -> (1-15) (mod 26) = -14 + 26 -> L
D -> (3 -15) (mod 26) = -12 + 26 -> O

In the above, the result is in the range 0 to 25; i.e., if x + n or x − n are not in the range 0 to 25, we have to subtract or add 26.)

We can decrypt the the message "WTAAD" using the Caesar Cipher with key=15 to "HELLO".

So, option (2) is correct answer

Previous	Next
UGC NET CS 2018 July - II Question 47	UGC NET CS 2018 July - II Question 49

UGC NET Computer Science July 2018 - II Question 47

Question 47

---

47. In Challenge-Response authentication the claimant ________.

Options:

1. (1) Proves that she knows the secret without revealing it
2. (2) Proves that she doesn’t know the secret
3. (3) Reveals the secret
4. (4) Gives a challenge

Answer : (1) Proves that she knows the secret without revealing it

Explanation Question 47

In cryptography, a zero-knowledge proof or zero-knowledge protocol is a method by which one party (the prover) can prove to another party (the verifier) that they know a value x, without conveying any information apart from the fact that they know the value x. The essence of zero-knowledge proofs is that it is trivial to prove that one possesses knowledge of certain information by simply revealing it; the challenge is to prove such possession without revealing the information itself or any additional information

Example:

WHAT IS ZERO KNOWLEDGE AUTHENTICATION?

Zero-knowledge authentication is when a prover convinces a verifier that she is in possession of an identifying secret, without revealing the secret itself. One example for zero-knowledge authentication is when a prover has an asymmetric key-pair (e.g. RSA, EC) and using the private key (the identifying secret) to respond to a challenge sent with the public key. The private key is never revealed, but the verifier is convinced that the prover has the key.

Previous	Next
UGC NET CS 2018 July - II Question 46	UGC NET CS 2018 July - II Question 48

UGC NET Computer Science July 2018 - II Question 46

Question 46

---

46. Which of the following statements are true ?
(a) Three broad categories of Networks are
(i) Circuit Switched Networks
(ii) Packet Switched Networks
(iii) Message Switched Networks
(b) Circuit Switched Network resources need not be reserved during the set up phase.
(c) In packet switching there is no resource allocation for packets.

Code :

1. (1) (a) and (b) only
2. (2) (b) and (c) only
3. (3) (a) and (c) only
4. (4) (a), (b) and (c)

Answer : (3) (a) and (c) only

Explanation Question 46

• TRUE (a) Three broad categories of Networks are (i) Circuit Switched Networks, (ii) Packet Switched Networks, (iii) Message Switched Networks
• FALSE (b) Circuit Switched Network resources need not be reserved during the set up phase.
• TRUE (c) In packet switching there is no resource allocation for packets.

Statement (b) is false because in Circuit Switched Network there is a need of pre-specified route from which data will travels and no other data is permitted. So, It reserves the route dusring the setup phase.

So, option (3) is correct answer

Here, this link is useful to differentiate type of networks :  DCN - Network Switching

Previous	Next
UGC NET CS 2018 July - II Question 45	UGC NET CS 2018 July - II Question 47