U.G.C. NET Exam. 4 December, 2019 Paper II (COMPUTER SCIENCE & APPLICATIONS)

Total Questions: 100

81. Consider the following learning algorithms:

(A) Logistic repression
(B) Back propagation
(C) Linear repression
Which of the following option represents classification algorithms?

Correct Answer: (e)*
Solution:

LEARNING ALGORITHM:- These algorithms are used in machine learning to help technology in human learning process. It is used to process data to extract patterns appropriate for application in a new system. From above given options, only (A) and (B) are learning algorithms.
(a) Logistic regression: It is used for binary classification problems. It is used to examine and describe the relationship between a binary variable and set of predicator variables. The primary objective of logistic regression is to model the mean of the response variables, given a set or predicator variables.
(b) Back Propagation:- It is the essence of neural net training. It is the method of fine tuning the weights of a neural net based on the error rate obtained in the previous iteration. It is a standard method of training artificial neural network.

82. Match List-I and List-II

Correct Answer: (c) A-2, B-4, C-1, D-3
Solution:

83. According to the ISO-9126 Standard Quality Model. Match the attributes given in List-I with their definition in List-II:

Correct Answer: (c) A-2, B-4, C-1, D-3
Solution:

84. Match the Agile Process models with the task performed during the model:

Correct Answer: (a) A-2, B-4, C-1, D-3
Solution:

85. Match List-I with List-II

Correct Answer: (c) A-4, B-3, C-2, D-1
Solution:

86. An Instruction is stored at location 500 with its address field at location 501. The address field has the value 400. A processor register R1 contains the number 200. Match the addressing mode (List-I), given below with effective address (List-II) for the given instruction:

Correct Answer: (a) A-3, B-1, C-4, D-2
Solution:

87. Match List-I and List-II

Correct Answer: (c) A-2, B-1, C-4, D-3
Solution:

88. Match List-I with List-II:

Correct Answer: (a) A-4, B-3, C-2, D-1
Solution:

89. The sequence diagram given in Figure for the Weather Information System takes place. When an external system requests the summarized data from the weather station. The me easing order of lifeline for the objects in the system are:

Correct Answer: (c) Weather data → Comms link → Weather station → Sat Comms
Solution:

In this scenario, first connection request is established, weather information system is requesting for the weather report. Request takes place as:
(1) Request will be sent from weather information system to sat communication.
(2) Sat communication is forwarding that request to weather station.
(3) Then weather station sends get (summary) request to communication link.
(4) After that, it will fetch data from weather data. Reply Process:
(1) As the communication link is nearest to weather data, first it will get the data.
(2) Then it goes from communication link to weather station.
(3) Then weather station to sat comm.
(4) At the end, weather information system get the weather information.
So increasing order of lifeline of objects in the system will be same as objects similar or larger distance from weather data, in the way reply is gone through. So it will be.
Weather data → Comms link → Weather station → Sat Comms.

90. The Data Encryption Standard (DES) has a function consists of four steps. Which of the following is correct order of these four steps?

Correct Answer: (b) an expansion permutation an XOR operation S-boxes a straight permutation
Solution:

Data Encryption standard (DES)- Data encryption standard (DES) is a block cipher that encrypts data in blocks of size 64 bits each. That is 64 bits of plain text goes input to the DES which produces 64 bit of cipher text key length is 56bits.
Explanation:
Broad level steps of DES are:
• In first step 64 bit plain text block is handed over to initial permutation.
• Next initial permutation (IP) produces two halves of permuted block, say left plain text and right plain text.
• Now each LPT and RPT go through 16 rounds of encryption process each with its own key.
• At the end, LPT and RPT are rejoined and a final permutation is performed on combined block.
During expansion permutation, it goes to S-box substitution after doing XOR of 48 bit key with 48 bit right plain text. S-Box produces the 32 bit output using substitution technique. A a straight permutation is done. These 32 bits are permuted using P-box.