# Recent questions tagged nielit2017dec-scientistb 1
Which one of the following statements are not correct? $S1$: $3$NF decomposition is always lossless join and dependency preserving. $S2$: $3$NF decomposition is always lossless join but may or may not be dependency preserving. $S3$: BCNF decomposition is always lossless join and dependency ... but may or may not be dependency preserving. Only $S1$ Only $S4$ Both $S1$ and $S4$ Both $S2$ and $S3$
2
According to the given language, which among the following expressions does it correspond to ? Language $L=\{x\in\{0,1\}\mid x\text{ is of length 4 or less}\}$. $(0+1+0+1+0+1+0+1)^4$ $(0+1)^4$ $(01)^4$ $(0+1+\varepsilon)^4$
3
Using bisection method, one root of $x^4-x-1$ lies between $1$ and $2$. After second iteration the root may lie in interval: $(1.25,1.5)$ $(1,1.25)$ $(1,1.5)$ None of the options.
4
In a cache memory if total number of sets are ‘$s$’, then the set offset is: $2^8$ $\log_2s$ $s^2$ $s$
5
Which of the following is machine independent optimization? Loop optimization Redundancy Elimination Folding All of the option
6
7
Let $G$ be a grammar in CFG and let $W_1,W_2\in L(G)$ such that $\mid W_1\mid=\mid W_2\mid$ then which of the following statements is true? Any derivation of $W_1$ has exactly the same number of steps as any derivation of $W_2$. Different derivation have different length. Some derivation of $W_1$ may be shorter than the derivation of $W_2$ None of the options
1 vote
8
Let $A$ be an array of $31$ numbers consisting of a sequence of $0$’s followed by a sequence of $1$’s. The problem is to find the smallest index $i$ such that $A[i]$ is $1$ by probing the minimum number of locations in $A$. The worst case number of probes performed by an optimal algorithm is $2$ $4$ $3$ $5$
9
Find the smallest number $y$ such that $y\times 162$ ($y$ multiplied by $162$) is a perfect cube $24$ $27$ $36$ $38$
10
A regular expression is $(a+b^{\ast}c)$ is equivalent to set of strings with either $a$ or one or more occurrence of $b$ followed by $c$. $(b^{\ast}c+a)$ set of strings with either $a$ or zero or more occurrence of $b$ followed by $c$. Both (B) and (C)
1 vote
11
Which of the following are undecidable? $P1$: The language generated by some CFG contains any words of length less than some given number $n$. $P2$: Let $L1$ be CFL and $L2$ be regular, to determine whether $L1$ and $L2$ have common elements $P3$: Any given CFG is ambiguous or not. ... CFG $G$, to determine whether epsilon belongs to $L(G)$ $P2$ only $P1$ and $P2$ only $P2$ and $P3$ only $P3$ only
12
Consider the following four processes with their corresponding arrival time and burst time: $\begin{array} \text{Process}&\text{Arrival time}&\text{Burst time(in ms)}\\ \text{P1}&0.0&8\\ \text{P2}&0.6&6\\ \text{P3}&3.8&4\\ \text{P4}&4.4&2\end{array}$ What is the average turn around time (in ms) for these processes using FCFS scheduling algorithm? $15$ $12.8$ $13$ none of the options
1 vote
13
Consider a non-pipelined machine with $6$ stages; the lengths of each stage are $\text{20ns, 10ns, 30ns,25ns, 40 ns}$ and $\text{15ns}$ respectively. Suppose for implementing the pipelining the machine adds $\text{5 ns}$ of overhead to each stage for clock skew and set up. What is the speed up factor of the pipelining system (ignoring any hazard impact)? $7$ $14$ $3.11$ $6.22$
14
We have $10$-stage pipeline, where the branch target conditions are resolved at stage $5$. How many stalls are there for an incorrectly predicted branch? $5$ $6$ $7$ $4$
15
In how many ways $8$ girls and $8$ boys can sit around a circular table so that no two boys sit together? $(7!)^2$ $(8!)^2$ $7!8!$ $15!$
1 vote
16
Which of the following is added to the page table in order to track whether a page of cache has been modified since it was read from the memory? Reference bit Dirty bit Tag bit Valid bit
17
The time taken to switch between user and kernel modes of execution be $t1$ while the time taken to switch between two processes be $t2$. Which of the following is TRUE? $t1>t2$ $t1=t2$ $t1<t2$ nothing can be said about the relation between $t1$ and $t2$
1 vote
18
In conservative two phase locking protocol, a transaction Should release all the locks only at the beginning of transaction Should release exclusive locks only after the commit operation Should acquire all the exclusive locks at the beginning of transaction Should acquire all the locks at the beginning of transaction
19
Recursive enumerable languages are not closed under _________. Set difference Complement Both (A) and (B) None of the options
20
Let $u$ and $v$ be two vectors in $R^2$ whose Eucledian norms satisfy $\mid u\mid=2\mid v \mid$. What is the value $\alpha$ such that $w=u+\alpha v$ bisects the angle between $u$ and $v$? $2$ $1$ $\dfrac{1}{2}$ $-2$
21
A system has $3$ processes sharing $4$ resources. If each process needs a maximum of $2$ units then, deadlock Can never occur Has to occur May occur None of the options
22
What is the meaning of regular expression $\Sigma^*001\Sigma^*$? Any string containing ‘$1$’ as substring Any string containing ‘$01$’ as substring Any string containing ‘$011$’ as substring All string containing ‘$001$’ as substring
23
Let $G$ be a complete undirected graph on $8$ vertices. If vertices of $G$ are labelled, then the number of distinct cycles of length $5$ in $G$ is equal to: $15$ $30$ $56$ $60$
1 vote
24
Which of the following is TRUE? Every relation in $3$NF is also in BCNF A relation R is in $3$NF if every non-prime attribute of R is fully functionally dependent on every key of R Every relation in BCNF is also in $3$NF No relation can be in both BCNF and $3$NF.
25
Consider the relational schema $R(A B C D)$ with following $FD$ set $F=\{A \to CE, B \to D, AE \to D\}$. Identify the highest normal form satisfied by the relation $R$. $2$NF BCNF $3$NF $1$NF
26
The grammar $S\rightarrow aSb\mid bSa\mid SS\mid \varepsilon$ is: Unambiguous CFG Ambiguous CFG Not a CFG Deterministic CFG
27
If any string of a language $L$ can be effectively enumerated by an enumerator in a lexicographic order then language $L$ is _______. Regular Context free but not necessarily regular Recursive but not necessarily context free Recursively enumerable but not necessarily recursive
A RAM chip has $7$ address lines, $8$ data lines and $2$ chips select lines. Then the number of memory locations is __________ $2^{12}$ $2^{10}$ $2^{19}$ $2^{13}$
Consider a complete binary tree where the left and the right sub trees of the root are max-heaps. The lower bound for the number of operations to convert the tree to a heap is: $\Omega(\log n)$ $\Omega(n\log n)$ $\Omega(n)$ $\Omega(n^2)$