UGC NET Computer Science 2024 Previous Year Questions (PYQs) – Page 20 of 20

Compiler phases:

Lexical analysis → Tokenization

Syntax analysis → Parsing

Semantic analysis → Type checking, type conversion, scope checking

Optimization → Loop optimization, data flow analysis

Thus type conversion belongs to semantic analysis.

In the TCP/IP model:

• IP (Internet Protocol) provides host-to-host communication between devices.

• TCP (Transmission Control Protocol) provides process-to-process communication using port numbers.

Minterms:

$0 = 000$

$2 = 010$

$6 = 110$

Don't care terms:

$1 = 001$

$3 = 011$

$5 = 101$

Using K-map simplification:

Group $(0,2)$ → $A'C'$

Group $(2,6)$ → $BC'$

Thus,

$F = A'C' + BC'$

Factorizing:

$F = C'(A' + B)$

Which simplifies to:

$F = A' + BC'$

Average Memory Access Time:

$AMAT = Hit\ Time + Miss\ Rate \times Miss\ Penalty$

Hit time = 100 ns

Miss rate = $1 - 0.9 = 0.1$

Miss penalty = $1100 - 100 = 1000$

So,

$AMAT = 100 + 0.1 \times 1000$

$AMAT = 100 + 100 = 200\ ns$

PPP provides:

• Frame format

• Link establishment (LCP)

• Authentication (PAP, CHAP)

PPP does not provide flow control or sequence numbering.

Thus:

A → Yes

B → Yes

E → Yes

Windows uses 32 priority levels:

• 0–15 → Non-real-time (variable priorities)

• 16–31 → Real-time priorities

Thus number of non-real-time priorities = 16.

Tree locking protocol (graph-based protocol) rules:

• The first lock may be on any node.

• A transaction may lock a node only if it already holds a lock on the parent.

• Nodes may be unlocked anytime but cannot be relocked.

Properties:

• Deadlock cannot occur because locking follows a hierarchical order.

• Transactions can lock data items earlier since unlocking can happen anytime.

Thus:

B → True

C → True

Find dominant growth for each.

A:

$3x^3+(\log x)^4$

Dominant term = $x^3$

$n=3$

B:

$(x^5+x^2+1)/(x^3+1) \approx x^2$

$n=2$

C:

$(x^3+x^2+1)/(x^2+1) \approx x$

$n=1$

D:

$(x^2+5\log x)/(x^2+1) \approx 1$

$n=0$

Thus:

D → $O(1)$

C → $O(x)$

B → $O(x^2)$

A → $O(x^3)$

Increasing order:

D, C, B, A

Each time an a is read:

$a \rightarrow$ push 3 a's onto the stack.

Each b pops one a from the stack.

Thus:

1 input a produces 3 stack symbols, so we need 3 b's to remove them.

Therefore the relation is:

$b = 3a$

Language:

${a^n b^{3n} \mid n>0}$