UGC NET CS 2018 Dec – II

Question 1

​Data warehouse contains___________ data that is never found in operational environment.

• A. Scripted
• B. Encoded
• C. Encrypted
• D. Summary

Answer: (D)

Data Warehouse is a relational database that is designed for query and analysis rather than for transaction processing. It usually contains historical data derived from transaction data, but it can include data from other sources. The goal is to produce statistical results that may help in decision makings. Option (D) is correct.

Question 2

Suppose a system has 12 instances of some resources with n processes competing for that resource. Each process may require 4 instances of the resource. The maximum value of n for which the system never enters into deadlock is

• A. 3
• B. 4
• C. 5
• D. 6

Answer: (A)

Given, Number of resources (R) = 12 Max need for each resource (N) = 3 Since deadlock-free condition is:

R ≥ P(N − 1) + 1 

Where R is total number of resources, P is the number of processes, and N is the max need for each resource.

12 ≥ P(4 − 1) + 1
11 ≥ 3P
11/3 ≥ P
P ≤ 3.66 

(Take, floor value for maximum) Therefore, the largest value of P that will always avoid deadlock is 3. Option (A) is correct.

Question 3

​To overcome difficulties in Readers-Writers problem, which of the following statement/s is/are true ?

1. Writers are given exclusive access to shared objects
2. Readers are given exclusive access to shared objects
3. Both readers and writers are given exclusive access to shared objects.

Choose the correct answer from the code given below:

• A. 1 only
• B. Both 2 and 3
• C. 2 only
• D. 3 only

Answer: (A)

In Readers-Writers Problem, since readers do not modify values, so these can be allowed with other readers. But writers are given exclusive access to shared objects. Only statement (1) is correct.

Question 4

Consider the following terminology and match List 1 and List 2 and choose the correct answer from the code given below b= branch factor d= depth of shallowest solution M= Maximum depth of the search tree I= depth limit

• A. (a)-(iii), (b)-(ii), (c)-(iv), (d)-(i)
• B. (a)-(ii), (b)-(iii), (c)-(iv), (d)-(i)
• C. (a)-(i), (b)-(ii), (c)-(iv), (d)-(iii)
• D. (a)-(i), (b)-(iii), (c)-(iv), (d)-(ii)

Answer: (B)

BFS → O(b^d) worst case space complexity DFS → O(bm) worst case space complexity Depth - Limited Search → O(bl) Iterative deepening Search → O(bd) Option (B) is correct.

Question 5

​The third generation mobile phone are digital and based on

• A. AMPS
• B. Broadband CDMA
• C. CDMA
• D. D-AMPS

Answer: (B)

First generation supports AMPS. Second generation supports D-AMPS and CDMA. Third generation of wireless communication technology, it supports broadband voice, data and multimedia communication technologies in wireless networks. Refer - https://en.wikipedia.org/wiki/Mobile_technology#Mobile_communication_industry[2] Option (B) is correct.

Question 6

Consider ISO-OSI network architecture reference model. Session layer of this model offer Dialog control, token management and ____________ as services.

• A. Synchronization
• B. Asynchronization
• C. Errors
• D. Flow control

Answer: (A)

Functions of Session Layer : Dialog Control, Managing Tokens, Synchronization. Flow control and error corrections are managed at Transport layer. Option (B) is correct.

Question 7

Consider the following two languages: L​₁​ = {x | for some y with | y| = 2^|x| , xy ∈ L and L is regular language} L₂​ = { x | for some y such that |x| = |y| , xy ∈ L and L is regular language} Which one of the following is correct?

• A. Both L​₁​ and L₂​ are regular languages
• B. Both L​₁​ and L₂​ are not regular languages
• C. Only L​₁​ is regular language
• D. Only L​₂ is regular language

Answer: (A)

Question 8

An internet service provider (ISP) has following chunk of CIDR-based IP addresses available with it: 245.248.128.0/20 . The ISP want to give half of this chunk of addresses to organization A and a quarter to Organization B while retaining the remaining with itself. Which of the following is a valid allocation of addresses to A and B ?

• A. 245.248.132.0/22 and 245.248.132.0/21
• B. 245.248.136.0/21 and 245.248.128.0/22
• C. 245.248.136.0/24 and 245.248.132.0/21
• D. 245.248.128.0/21 and 245.248.128.0/22

Answer: (B)

See Question 4 of https://www.geeksforgeeks.org/computer-networks-set-1/ Option (B) is correct.

Question 9

​The Software Requirement Specification(SRS) is said to be _________ if and only if no subset of individual requirements described in it conflict with each other.

• A. Correct
• B. Consistent
• C. Unambiguous
• D. Verifiable

Answer: (B)

• SRS is said to be correct if it covers all the requirements that are actually expected from the system.
• Requirements in SRS are said to be consistent if there are no conflicts between any set of requirements. Examples of conflict include differences in terminologies used at separate places, logical conflicts like time period of report generation, etc.
• An SRS is said to be unambiguous if all the requirements stated have only 1 interpretation.
• An SRS is verifiable if there exists a specific technique to quantifiably measure the extent to which every requirement is met by the system.

Option (B) is correct.

Question 10

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

(⌐ A ∨​ ⌐B ∨​ ⌐C ∨​ ⌐ ​D) 

• A. 8
• B. 7
• C. 15
• D. 16

Answer: (C)

There are four variables A, B, C, D. Therefore 2^4 = 16. From 0 to 15 models are exist, but one is 0, so 15 is correct answer.