13739844
Pregunta 1
Pregunta
... is a measure of uncertainty
Respuesta
-
Encoding
-
Entropy
-
Information
-
Redundancy
Pregunta 2
Pregunta
{1,2,3,4,5,6} is the sample space of ...
Respuesta
-
one coin toss
-
one dice roll
-
sum of two dice
-
removing a card from the standard deck
Pregunta 3
Pregunta
A redundancy of a code S = ...
Respuesta
-
1 - Iavr/Imax
-
Iavr/Imax
-
1 + Iavr/Imax
-
Imax/Iavr
Pregunta 4
Pregunta
An average length of codewords qavr = ...
Respuesta
-
∑ (pi * qi)
-
∑ (pi / qi)
-
∑ pi
-
∑ qi
Pregunta 5
Pregunta
An efficiency of a code E = ...
Respuesta
-
Iavr/Imax
-
Imax/Iavr
-
Iavr/100
-
Imax - Iavr
Pregunta 6
Pregunta
ASCII code is a
Respuesta
-
Variable length code
-
Fixed length code
-
Error-correction code
-
None of the given
Pregunta 7
Pregunta
By the Bayes' rule for conditional entropy H(Y|X) \= ...
Respuesta
-
H(X|Y) - H(X) + H(Y)
-
[P(B|A)][P(A)] /P(B)
-
H(X|Y) - H(X)
-
H(X|Y)+ H(Y)
Pregunta 8
Pregunta
By the Bayes' theorem ...
Respuesta
-
P(B|A) = P(A and B)/P(A)
-
P(A|B) = [P(B|A)][P(A)] /P(B)
-
P(B|A) = P(A and B)*P(A)
-
P(A|B) = [P(B|A)][P(A)] * P(B)
Pregunta 9
Pregunta
21. By the Chain rule H(X,Y) \= H(Y|X) + ...
Respuesta
-
H(X)
-
H(Y)
-
H(Y|X)
-
H(X|Y)
Pregunta 10
Pregunta
By the Hartley's formula the amount of information I = ...
Respuesta
-
I = n*log m
-
I = m*n
-
I = log (m/n)
-
I = log (m*n)
Pregunta 11
Pregunta
By the Hartley's formula the entropy H = ...
Respuesta
-
H \= - ∑(pi * log pi)
-
H \= - ∑ (log pi)
-
H \= log m
-
H \= - ∑ (pi / log pi)
Pregunta 12
Pregunta
By the property of joint entropy H(X,Y) <= ...
Respuesta
-
H(X)
-
H(Y)
-
H(X) + H(Y)
-
None of the given
Pregunta 13
Pregunta
By the property of joint entropy H(X,Y) ...
Respuesta
-
H(X,Y) >= H(X) and H(X,Y) <= H(Y)
-
H(X,Y) <= H(X) and H(X,Y) >= H(Y)
-
H(X,Y) >= H(X) and H(X,Y) >= H(Y)
-
H(X,Y) >= H(X) + H(Y)
Pregunta 14
Pregunta
By the Shannon's formula the amount of information I = ...
Respuesta
-
H \= - n * ∑( pi * log pi)
-
H \= - n * ∑ (log pi)
-
H \= - n * ∑ pi
-
H \= - n * ∑ (pi / log pi)
Pregunta 15
Pregunta
By the Shannon's formula the entropy H = ...
Respuesta
-
H \= - ∑( pi * log pi)
-
H \= - ∑ (log pi)
-
H \= - ∑ pi
-
H \= - ∑ (pi / log pi)
Pregunta 16
Pregunta
Calculate the code rate for Hamming (15,11) code
Respuesta
-
1
-
0,733
-
0,571
-
0,839
Pregunta 17
Pregunta
Calculate the code rate for Hamming (31,26) code
Respuesta
-
1
-
0,839
-
0,733
-
0,571
Pregunta 18
Pregunta
Choose the formula to determine the number N of possible messages with length n if the message source alphabet consists of m characters, each of which can be an element of the message
Respuesta
-
N = mn
-
N = nm
-
N = m*n
-
N = log m
Pregunta 19
Pregunta
Code is optimal when ...
Respuesta
-
qavr = H
-
qavr ≠H
-
qavr <H
-
qavr >H
Pregunta 20
Pregunta
Code rate R (k information bits and n total bits) is defined as
Respuesta
-
k = n/R
-
R = k * n
-
n = R * k
-
R = k/n
Pregunta 21
Pregunta
Conditional entropy H(Y|X) lies between
Respuesta
-
- H(Y) and 0
-
0 and H(Y)
-
- H(Y) and H(Y)
-
0 and 1
Pregunta 22
Pregunta
Conditional probability P(B|A) = ...
Respuesta
-
P(A and B)/P(A)
-
[P(B|A)][P(A)] /P(B)
-
P(A and B)*P(A)
-
[P(B|A)][P(A)] * P(B)
Pregunta 23
Pregunta
Find the information amount of a symbol from the language with total number of symbols n = 18.
Respuesta
-
I = log218
-
I = log182
-
I = 18 * log218
-
I = 18 * log182
Pregunta 24
Pregunta
For a Hamming (15, 11) code, 15 is the total number of bits and 11 is the number of ...
Respuesta
-
redundant bits
-
data bits
-
parity bits
-
none of the given
Pregunta 25
Pregunta
Which of the following symbols will get the shortest codeword after Shannon-Fano coding if probabilities are p(a) = 0.05, p(b) = 0.6, p(c) = 0.2 and p(d) = 0.15?
Respuesta
-
c
-
a
-
d
-
b
Pregunta 26
Pregunta
Which of the following is not a correct statement about a probability.
Respuesta
-
It must have a value between 0 and 1
-
It is the collection of several experiments
-
A value near 0 means that the event is not likely to occur/happens
-
It can be reported as a decimal or a fraction
Pregunta 27
Pregunta
Which of the following is a part the channel coding?
Respuesta
-
Huffman code
-
Hamming code
-
Shannon-Fano code
-
RLE code
Pregunta 28
Pregunta
For a Hamming (31, 26) code, 31 is the total number of bits and 26 is the number of ...
Respuesta
-
redundant bits
-
data bits
-
parity bits
-
none of the given
Pregunta 29
Pregunta
For Hamming distance d<sub>min</sub> and s errors in the received word, the condition to be able to correct the errors is
Respuesta
-
dmin>= s+1
-
dmin>= 2s+1
-
dmin>= 2s+2
-
dmin>= s+2
Pregunta 30
Pregunta
Hamming distance can easily be found with ...
Respuesta
-
XNOR operation
-
XOR operation
-
OR operation
-
AND operation
Pregunta 31
Pregunta
In a throw of coin what is the probability of getting head.
Respuesta
-
1
-
1/2
-
2
-
0
Pregunta 32
Pregunta
Specify the formula to calculate numbers of k and n bits to create the Hamming code
Respuesta
-
(n, k) = (2r - 1, 2r - 1 - r)
-
(n, k) = (2r, 2r - 1 - r)
-
(n, k) = (2r - 1, 2r - r)
-
(n, k) = (2r - 1, 2r - 1 + r)
Pregunta 33
Pregunta
In a throw of coin what is the probability of getting tails.
Respuesta
-
1
-
1/2
-
2
-
0
Pregunta 34
Pregunta
Specify the formula to find the amount of information if events have different probabilities.
Respuesta
-
Hartley's formula
-
Shannon's formula
-
Fano's formula
-
Bayes' formula
Pregunta 35
Pregunta
Specify the formula to find the amount of information if events have the same probabilities.
Respuesta
-
Shannon's formula
-
Hartley's formula
-
Fano's formula
-
Bayes' formula
Pregunta 36
Pregunta
Specify the most effective type of code when an alphabet consists of 2 symbols with probabilities p(x1) = 0,05 and p(x2) = 0,95.
Respuesta
-
ASCII code
-
Shannon-Fano's code
-
Shannon-Fano's code by blocks
-
Hartley's code
Pregunta 37
Pregunta
In digital communication system, smaller the code rate, ... are the redundant bits.
Respuesta
-
a. less
-
b. equal
-
c. more
-
d. unpredictable
Pregunta 38
Pregunta
Specify the right formula if dmin is Hamming distance, s - number of correctable errors and r - number of detectable errors.
Respuesta
-
dmin>= s+r+1
-
dmin>= 2s+r+1
-
dmin>= s+2r+1
-
dmin>= s+r+2
Pregunta 39
Pregunta
Specify two types of error control algorithms
Respuesta
-
block and linear
-
linear and nonlinear
-
block and convolution
-
none of the given
Pregunta 40
Pregunta
Noise affects ...
Respuesta
-
information source
-
receiver
-
channel
-
transmitter
Pregunta 41
Pregunta
The basic idea behind Shannon-Fano coding is to
Respuesta
-
compress data by using more bits to encode more frequently occuring characters
-
compress data by using fewer bits to encode more frequently occuring characters
-
compress data by using fewer bits to encode fewer frequently occuring characters
-
expand data by using fewer bits to encode more frequently occuring characters
Pregunta 42
Pregunta
Probability of occurrence of an event lies between
Respuesta
-
-1 and 0
-
0 and 1
-
-1 and 1
-
exactly 1
Pregunta 43
Pregunta
The Hamming distance between "client" and "server" is
Respuesta
-
0
-
1
-
6
-
impossible to detect
Pregunta 44
Pregunta
The Hamming distance between "make" and "made" is
Respuesta
-
4
-
3
-
1
-
impossible to detect
Pregunta 45
Pregunta
The Hamming distance between "push" and "pull" is
Respuesta
-
0
-
4
-
2
-
impossible to detect
Pregunta 46
Pregunta
Probability of second event in situation if first event has been occurred is classified as
Respuesta
-
conditional probability
-
joint entropy
-
conditional entropy
-
none of the given
Pregunta 47
Pregunta
The Hamming distance between "starting" and "finishing" is
Respuesta
-
4
-
3
-
impossible to detect
-
5
Pregunta 48
Pregunta
The Hamming distance between 001111 and 010011 is
Respuesta
-
1
-
2
-
3
-
4
Pregunta 49
Pregunta
Shannon-Fano and Huffman codes are an encoding algorithms used for
Respuesta
-
lossy data compression
-
lossless data compression
-
error correction
-
error detection
Pregunta 50
Pregunta
The Hamming distance between 010111 and 010011 is
Respuesta
-
2
-
3
-
1
-
4
Pregunta 51
Pregunta
The Hamming distance between 011111 and 010011 is
Respuesta
-
1
-
3
-
2
-
4
Pregunta 52
Pregunta
Specify parts of the receiver side
Respuesta
-
Source encoder, channel encoder, digital modulator
-
Source decoder, channel decoder, digital demodulator
-
Source decoder, channel encoder, digital modulator
-
Source encoder, channel decoder, digital modulator
Pregunta 53
Pregunta
The Hamming distance between 101001 and 010011 is
Respuesta
-
1
-
2
-
4
-
3
Pregunta 54
Pregunta
The Hamming distance between two strings with equal length is ...
Respuesta
-
the number of positions at which the corresponding symbols are different
-
the number of positions at which the corresponding symbols are equal
-
the number of identical symbols in the first string
-
the number of identical symbols in the second string
Pregunta 55
Pregunta
Specify parts of the transmitter side
Respuesta
-
Source decoder, channel decoder, digital demodulator
-
Source encoder, channel encoder, digital modulator
-
Source decoder, channel encoder, digital modulator
-
Source encoder, channel decoder, digital modulator
Pregunta 56
Pregunta
The number of digits by which any two binary sequences differ is called the ...
Respuesta
-
Hamming weight
-
Hamming distance
-
Hamming code
-
Hamming length
Pregunta 57
Pregunta
Specify the case when entropy is maximum
Respuesta
-
p1=0,5 and p2=0,5
-
p1=1 and p2=0
-
p1=0 and p2=1
-
p1=0,9 and p2=0,1
Pregunta 58
Pregunta
The prefix code is also known as ...
Respuesta
-
block code
-
uniquely decodable code
-
convolutional code
-
parity bit
Pregunta 59
Pregunta
In a throw of dice what is the probability of getting number greater than 5.
Respuesta
-
a. 1/3
-
b. 1/6
-
c. 1/5
-
d. 1
Pregunta 60
Pregunta
The string was encoded with Hamming (15,11) code using the transformation matrix. Specify numbers of positions of the parity bits.
Respuesta
-
12,13,14,15
-
1,2,3,4
-
1,2,4,8
-
2,3,4,5
Pregunta 61
Pregunta
78. For a Hamming (31, 26) code, 31 is the total number of bits and 26 is the number of ...
Respuesta
-
a. redundant bits
-
b. data bits
-
c. parity bits
-
d. none of the given
Pregunta 62
Pregunta
The string was encoded with Hamming (31,26) code using the transformation matrix. Specify numbers of positions of the parity bits.
Respuesta
-
27,28,29,30,31
-
1,2,3,4,5
-
1,2,4,8,16
-
2,3,4,5,6
Pregunta 63
Pregunta
79. For a Hamming (7, 4) code, 7 is the total number of bits and 4 is the number of ...
Respuesta
-
a. redundant bits
-
b. data bits
-
c. parity bits
-
d. none of the given
Pregunta 64
Pregunta
When data is compressed, the goal is to reduce
Respuesta
-
noise
-
redundancy
-
channel capacity
-
none of the given
Pregunta 65
Pregunta
When the base of the logarithm is 10, then the unit of measure of information is
Respuesta
-
bytes
-
dits
-
nits
-
bits
Pregunta 66
Pregunta
43. Code has dmin = 3. How many errors can be detected by this code?
Respuesta
-
1
-
3
-
2
-
4
Pregunta 67
Pregunta
When the base of the logarithm is 2, then the unit of measure of information is
Respuesta
-
bytes
-
bits
-
nits
-
dits
Pregunta 68
Pregunta
When the base of the logarithm is e, then the unit of measure of information is
Respuesta
-
bytes
-
nits
-
dits
-
bits
Pregunta 69
Pregunta
Which block or device does the data compression?
Respuesta
-
Channel encoder
-
Source encoder
-
Modulator
-
None of the given
Pregunta 70
Pregunta
Which letter will get the shortest codeword after Huffman coding of the word "abracadabra"?
Respuesta
-
c
-
r
-
d
-
a
Pregunta 71
Pregunta
Which of the following codes has the highest code rate?
Respuesta
-
code rate is constant for all of the Hamming codes
-
Hamming (31,26)
-
Hamming (15,11)
-
Hamming (7,4)
Pregunta 72
Pregunta
Which of the following codes has the highest redundancy?
Respuesta
-
redundancy is constant for all of the Hamming codes
-
Hamming (7,4)
-
Hamming (15,11)
-
Hamming (31,26)
Pregunta 73
Pregunta
Which of the following codes is non-uniform?
Respuesta
-
Shannon-Fano
-
ASCII
-
Hamming
-
None of the given
Pregunta 74
Pregunta
Which of the following codes is prefix?
Respuesta
-
0, 111, 11
-
0, 111, 10
-
0, 101, 10
-
00, 10, 101
Pregunta 75
Pregunta
Which of the following codes is prefix?
Respuesta
-
0, 01, 11
-
0, 10, 11
-
0, 10, 1
-
0, 01, 001
Pregunta 76
Pregunta
Which of the following codes is uniform?
Respuesta
-
ASCII
-
Shannon-Fano
-
Huffman
-
None of the given
Pregunta 77
Pregunta
Which of the following codes is uniform?
Respuesta
-
10,011,11,001,010
-
0,10,110,1110,1111
-
10,01,0001,100,1010
-
100,110,001,000,010
Pregunta 78
Pregunta
Which of the following indicate(s) an error in a received combination?
Respuesta
-
Parity bits
-
Error syndrome
-
Data bits
-
None of the given
Pregunta 79
Pregunta
The string was encoded with Hamming (7,4) code using the transformation matrix. Specify numbers of positions of the parity bits.
Respuesta
-
a. 5,6,7
-
a. 1,2,3
-
a. 1,2,4
-
a. 2,3,4
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