Sample Questions, Previous Year Solved Papers, Study Materials For Competitive Examinations Like UGC NET, SET And GATE Computer Science.

## Friday, 27 January 2017

61.       Given the following two statements:
A. L = {w|na(w) = nb(w)} is deterministic context free language, but not linear.
B. L = {an bn} U {an b2n} is linear, but not deterministic context free language.
Which of the following options is correct?
(1) Both (A) and (B) are false.
(2) Both (A) and (B) are true.
(3) (A) is true, (B) is false.
(4) (A) is false, (B) is true.
62.       Which of the following pairs have different expressive power?
(1) Single-tape-turing machine and multi-dimensional turing machine.
(2) Multi-tape turing machine and multi-dimensional turing machine.
(3) Deterministic push down automata and non-deterministic pushdown automata.
(4) Deterministic finite automata and Non-deterministic finite automata.
63.       Which of the following statements is false?
(1) Every context-sensitive language is recursive.
(2) The set of all languages that are not recursively enumerable is countable.
(3) The family of recursively enumerable languages is closed under union.
(4) The families of recursively enumerable and recursive languages are closed under reversal.
64.       Let C be a binary linear code with minimum distance 2t + 1 then it can correct upto ............bits of error.
(1) t + 1
(2) t
(3) t - 2
(4) t/2
65.       A t-error correcting q-nary linear code must satisfy:
Where M is the number of code words and X is
(1) qn
(2) qt
(3) q-n
(4) q-t

66.       Names of some of the Operating Systems are given below:
(a) MS-DOS
(b) XENIX
(c) OS/2
In the above list, following operating systems didn’t provide multiuser facility.
(1) (a) only
(2) (a) and (b) only
(3) (b) and (C) only
(4) (a), (b) and (c)
67.       From the given data below:
a b b a a b b a a b
which one of the following is not a word in the dictionary created by LZ-coding (the initial words are a, b)?
(1) a b
(2) b b
(3) b a
(4) b a a b
68.       With respect to a loop in the transportation table, which one of the following is not correct?
(1) Every loop has an odd no. of cells and at least 5.
(2) Closed loops may or may not b square in shape.
(3) All the cells in the loop that have a plus or minus sign, except the starting cell, must be occupied cells.
(4) Every loop has an even no. of cells and at least four.
69.       At which of the following stage(s), the degeneracy do not occur in transportation problem?
(m, n represents number of sources and destinations respectively)
(a) While the values of dual variables ui and vj cannot be computed.
(b) While obtaining an initial solution, we may have less than m + n -1 allocations.
(c) At any stage while moving towards optimal solution, when two or more occupied cells with the same minimum allocation become unoccupied simultaneously.
(d) At a stage when the no. of +ve allocation is exactly m + n - 1.
(1) (a), (b) and (c)
(2) (a), (c) and (d)
(3) (a) and (d)
(4) (a), (b), (c) and (d)
70.    Consider the following LPP:
Min. Z = x1+x2+x3
Subject to 3x1 + 4x3 ≤ 5
5x1 + x2 + 6x3 =7
8x1 + 9x3 ≥ 2
x1, x2, x3 ≥ 0
The standard form of this LPP shall be:
(1) Min. Z = x1 + x2 + x3 + 0x4 + 0x5
Subject to 3x1 + 4x3 + x4 = 5;
5x1 + x2 + 6x3 =7;
8x1 + 9x3 - x5 = 2;
x1, x2, x3, x4, x5 ≥ 0
(2) Min. Z = x1 + x2 + x3 + 0x4 + 0x5 -1(x6)-1(x7)
Subject to 3x1 + 4x3 + x4 = 5;
5x1 + x2 + 6x3 +x6 = 7;
8x1 + 9x3 - x5 + x7 = 2;
x1 to x7 ≥0
(3) Min. Z = x1 + x2 + x3 + 0x4 + 0x5 + 0x6
Subject to 3x1 + 4x3 + x4 = 5;
5x1 + x2 + 6x3 = 7;
8x1 + 9x3 - x5 + x6 = 2;
x1 to x6 ≥ 0
(4) Min. Z = x1 + x2 + x3 + 0x4 + 0x5 + 0x6+ 0x7
Subject to 3x1 + 4x3 + x4 = 5;
5x1 + x2 + 6x3 + x6 = 7;
8x1 + 9x3 - x5 + x7 = 2;
x1 to x7 ≥ 0