Thursday, June 12, 2014

THEORY OF COMPUTER SCIENCE (TCS) MAY 2013 COMPUTER SCIENCE SEMESTER 5

THEORY OF COMPUTER SCIENCE (TCS) MAY 2013 COMPUTER SCIENCE SEMESTER 5

Con. 6972-13.                                                                                            GS-9099
                                                         (3 Hours)                                [Total Marks : 100]

N.B. (1) Question No. 1 is compulsory.
        (2) Attempt any four questions from remaining six questions.
        (3) Draw suitable diagrams wherever necessary.
        (4) Assume suitable data, if necessary.
        (5) Maximum weightage is given to technical notations.

1. (a)Define the following terms :-5
      (i) Undecidability
     (ii) Unrestricted grammar
     (iii) Pumping lemma.
    (b)Define TM and Give its variants.5
    (c)Explain Chomsky hierarchy for formal languages.5
    (d)Give the closure properties of regular languages.5

2. (a)

(i) What is ambiguous CFG ? Give one example of ambiguous CFG.
5
(ii) What is Myhill-Nerode theorem ? Explain necessity of it.5
    (b)Let G be the grammar, find the leftmost derivation , right most derivation and parse10
tree for the string 00110101
            S → OB / 1A
            A → O/OS/1AA
            B → 1/1S/OBB

3. (a)

Explain CNF and GNF with example.

10
    (b)Give the formal definition of RE and design a DFA corresponding to the regular5
expression
       (a+b) * aba (a+b)*
    (c)Using pumping lemma prove that the following language is regular or not5


4. (a)Write NFA for accepting the following RE10
(a+bb)* + ϵ)
    (b)Explain DPDA and NPDA with languages of them.10

5. (a)

Find the languages defined by the following grammar :

10
          (i) S → OA/ IC
              A → OS / IB / ϵ
              B → 1A / OC
              C → OB / 1S
         (ii) S → OA / IC
              A → OS / IB
              B → OC / IA / ϵ
              C → OB / IS
    (b)Construct the PDA accepting following language10

6. (a)

Differentiate between Moore and Mealy machine with proper example and usage

10
Cary out conversion of Moore MIC to Mealy MIC.
    (b)Design a Turing machine to accept the language 10

7.     Write short notes on any four :-                                                                            20
              (a) Recursive and recursively enumerable languages
              (b) Intractable problems
              (c) Simplification of CFGs
              (d) Decision properties of regular languages
              (e) Rice's theorem.

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