U.G.C. NET Exam. June, 2020 Paper II (COMPUTER SCIENCE & APPLICATIONS)

Black- box testing, also known as behavioral testing, focuses on the software's, functional specifications. In other words, black - box testing allows a software developer to create sets of input conditions that completely exercise all of a program's functional requirements. The methods for behavioral testing are as follows.
(1) graph -based testing methods
(2) Equivalence partitioning
(3) boundary value analysis
(4) Comparison testing
(5) orthogonal array testing

(A) its worst - case running time is O(g(n)) and its best - case running time is
Ω(g(n)). ( O= big O) → True.
Big - oh (O) denotes upper bound or worst case.
Big- omega (Ω) denotes lower bound or best case.
Big - Theta (θ) denotes Average bound or average case.
(B) its worst - case running time is Ω (g(n)) and its bestcase running time is O(g(n)). (O = big O)
false, worst case should be Big-oh and best case should be big - omega.
(C) O (g(n)) = Ω (g(n)) (O= big O) False, cannot cover Big Omega.
(D) O (g(n)) ∩ ω(g(n)) is non-empty set (0 = Small O) false, no such f(n) Exists, i.e. the inter section is indeed the Empty set.

Any tree is 2- Colourable. True every tree is no loops and a bipartite graph with chromatic number 2. odd levels coloured with one colour and even level coloured with another colour.
• A graph G has no cycles of even length if it is bipartite. false.
• A graph G is 2- Colourable it is bipartite True. A graph K (2,3) set of V1 vertices coloured with one colour and set of V2 vertices Coloured with another colour.
• A graph G can be colour with d+1 colours if d is the maximum degree of any vertex in the graph G. True as the vertex of degree d means it is adjacent to vertices
Hence need a d + 1 different colours required.
• A graph G can be coloured with O(log|v|) Colours if it has O |v| degrees. false as kn has O (n ∧ 2) edges with Chromatic number n So it needs O (√v) Colours.

A Hash function H accepts a variable - length block of data M as input and produces a fixed - size has value h = H (M) In general terms, the principal object of a hash function is data integrity. A change to any bit or bits in m results, with high Probability in a change to the has code.

* D = dicidable
*UD = undecidable
According to the above table, rows 3, 4 and 8 it's undecidable.
Hence, the correct answer is (a), (b) and (c).

• A is ambiguous because λ can be generate using leftmost derivation having two different parse trees with an empty string.

Hence the correct answer is (A) (B) and (C).

Virtualization is a technique where multiple operating systems run simultanenously on a single machine virtually.
These machine can be accessed remotely by different users at the same time. Here, the same hardware like memory and CPU are utilized by all the operating systems in a systematic manner.

Statement A :- TRUE-
Post office protocol (POP) is a type of computer networking and Internet standard protocol that has modes, delete mode and keep mode.
Statement -B (TRUE)- In delete mode the mail is deleted from the mail box after each retrieval.
Statement E:- (TRUE) In keep made, mail remains in a mail box after retrieval.
Note:- Delete mode (delete after reading) keep mode (stores ever after reading).

Network layer firewall can filter on source and destination IP address source and Destination port no for both TCP and UDP packet.
• Firewall :- A firewall is a from of cyber security device that filters networks traffic. Network nodes can be separated from external traffic source, Internal traffic sources or even individual applications using firewall.