Csse 1502
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Csse 1502
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IT - Theory Part

IT - Theory Part

Question 1 of 79

1

... is a measure of uncertainty

Select one or more of the following:

  • Encoding

  • Entropy

  • Information

  • Redundancy

Explanation

Question 2 of 79

1

{1,2,3,4,5,6} is the sample space of ...

Select one or more of the following:

  • one coin toss

  • one dice roll

  • sum of two dice

  • removing a card from the standard deck

Explanation

Question 3 of 79

1

A redundancy of a code S = ...

Select one or more of the following:

  • 1 - Iavr/Imax

  • Iavr/Imax

  • 1 + Iavr/Imax

  • Imax/Iavr

Explanation

Question 4 of 79

1

An average length of codewords qavr = ...

Select one or more of the following:

  • ∑ (pi * qi)

  • ∑ (pi / qi)

  • ∑ pi

  • ∑ qi

Explanation

Question 5 of 79

1

An efficiency of a code E = ...

Select one or more of the following:

  • Iavr/Imax

  • Imax/Iavr

  • Iavr/100

  • Imax - Iavr

Explanation

Question 6 of 79

1

ASCII code is a

Select one or more of the following:

  • Variable length code

  • Fixed length code

  • Error-correction code

  • None of the given

Explanation

Question 7 of 79

1

By the Bayes' rule for conditional entropy H(Y|X) \= ...

Select one or more of the following:

  • H(X|Y) - H(X) + H(Y)

  • [P(B|A)][P(A)] /P(B)

  • H(X|Y) - H(X)

  • H(X|Y)+ H(Y)

Explanation

Question 8 of 79

1

By the Bayes' theorem ...

Select one or more of the following:

  • 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)

Explanation

Question 9 of 79

1

21. By the Chain rule H(X,Y) \= H(Y|X) + ...

Select one or more of the following:

  • H(X)

  • H(Y)

  • H(Y|X)

  • H(X|Y)

Explanation

Question 10 of 79

1

By the Hartley's formula the amount of information I = ...

Select one or more of the following:

  • I = n*log m

  • I = m*n

  • I = log (m/n)

  • I = log (m*n)

Explanation

Question 11 of 79

1

By the Hartley's formula the entropy H = ...

Select one or more of the following:

  • H \= - ∑(pi * log pi)

  • H \= - ∑ (log pi)

  • H \= log m

  • H \= - ∑ (pi / log pi)

Explanation

Question 12 of 79

1

By the property of joint entropy H(X,Y) <= ...

Select one or more of the following:

  • H(X)

  • H(Y)

  • H(X) + H(Y)

  • None of the given

Explanation

Question 13 of 79

1

By the property of joint entropy H(X,Y) ...

Select one or more of the following:

  • 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)

Explanation

Question 14 of 79

1

By the Shannon's formula the amount of information I = ...

Select one or more of the following:

  • H \= - n * ∑( pi * log pi)

  • H \= - n * ∑ (log pi)

  • H \= - n * ∑ pi

  • H \= - n * ∑ (pi / log pi)

Explanation

Question 15 of 79

1

By the Shannon's formula the entropy H = ...

Select one or more of the following:

  • H \= - ∑( pi * log pi)

  • H \= - ∑ (log pi)

  • H \= - ∑ pi

  • H \= - ∑ (pi / log pi)

Explanation

Question 16 of 79

1

Calculate the code rate for Hamming (15,11) code

Select one or more of the following:

  • 1

  • 0,733

  • 0,571

  • 0,839

Explanation

Question 17 of 79

1

Calculate the code rate for Hamming (31,26) code

Select one or more of the following:

  • 1

  • 0,839

  • 0,733

  • 0,571

Explanation

Question 18 of 79

1

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

Select one or more of the following:

  • N = mn

  • N = nm

  • N = m*n

  • N = log m

Explanation

Question 19 of 79

1

Code is optimal when ...

Select one or more of the following:

  • qavr = H

  • qavr &ne;H

  • qavr <H

  • qavr >H

Explanation

Question 20 of 79

1

Code rate R (k information bits and n total bits) is defined as

Select one or more of the following:

  • k = n/R

  • R = k * n

  • n = R * k

  • R = k/n

Explanation

Question 21 of 79

1

Conditional entropy H(Y|X) lies between

Select one or more of the following:

  • - H(Y) and 0

  • 0 and H(Y)

  • - H(Y) and H(Y)

  • 0 and 1

Explanation

Question 22 of 79

1

Conditional probability P(B|A) = ...

Select one or more of the following:

  • 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)

Explanation

Question 23 of 79

1

Find the information amount of a symbol from the language with total number of symbols n = 18.

Select one or more of the following:

  • I = log218

  • I = log182

  • I = 18 * log218

  • I = 18 * log182

Explanation

Question 24 of 79

1

For a Hamming (15, 11) code, 15 is the total number of bits and 11 is the number of ...

Select one or more of the following:

  • redundant bits

  • data bits

  • parity bits

  • none of the given

Explanation

Question 25 of 79

1

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?

Select one or more of the following:

  • c

  • a

  • d

  • b

Explanation

Question 26 of 79

1

Which of the following is not a correct statement about a probability.

Select one or more of the following:

  • 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

Explanation

Question 27 of 79

1

Which of the following is a part the channel coding?

Select one or more of the following:

  • Huffman code

  • Hamming code

  • Shannon-Fano code

  • RLE code

Explanation

Question 28 of 79

1

For a Hamming (31, 26) code, 31 is the total number of bits and 26 is the number of ...

Select one or more of the following:

  • redundant bits

  • data bits

  • parity bits

  • none of the given

Explanation

Question 29 of 79

1

For Hamming distance d<sub>min</sub> and s errors in the received word, the condition to be able to correct the errors is

Select one or more of the following:

  • dmin>= s+1

  • dmin>= 2s+1

  • dmin>= 2s+2

  • dmin>= s+2

Explanation

Question 30 of 79

1

Hamming distance can easily be found with ...

Select one or more of the following:

  • XNOR operation

  • XOR operation

  • OR operation

  • AND operation

Explanation

Question 31 of 79

1

In a throw of coin what is the probability of getting head.

Select one or more of the following:

  • 1

  • 1/2

  • 2

  • 0

Explanation

Question 32 of 79

1

Specify the formula to calculate numbers of k and n bits to create the Hamming code

Select one of the following:

  • (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)

Explanation

Question 33 of 79

1

In a throw of coin what is the probability of getting tails.

Select one or more of the following:

  • 1

  • 1/2

  • 2

  • 0

Explanation

Question 34 of 79

1

Specify the formula to find the amount of information if events have different probabilities.

Select one of the following:

  • Hartley's formula

  • Shannon's formula

  • Fano's formula

  • Bayes' formula

Explanation

Question 35 of 79

1

Specify the formula to find the amount of information if events have the same probabilities.

Select one of the following:

  • Shannon's formula

  • Hartley's formula

  • Fano's formula

  • Bayes' formula

Explanation

Question 36 of 79

1

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.

Select one of the following:

  • ASCII code

  • Shannon-Fano's code

  • Shannon-Fano's code by blocks

  • Hartley's code

Explanation

Question 37 of 79

1

In digital communication system, smaller the code rate, ... are the redundant bits.

Select one or more of the following:

  • a. less

  • b. equal

  • c. more

  • d. unpredictable

Explanation

Question 38 of 79

1

Specify the right formula if dmin is Hamming distance, s - number of correctable errors and r - number of detectable errors.

Select one of the following:

  • dmin>= s+r+1

  • dmin>= 2s+r+1

  • dmin>= s+2r+1

  • dmin>= s+r+2

Explanation

Question 39 of 79

1

Specify two types of error control algorithms

Select one of the following:

  • block and linear

  • linear and nonlinear

  • block and convolution

  • none of the given

Explanation

Question 40 of 79

1

Noise affects ...

Select one or more of the following:

  • information source

  • receiver

  • channel

  • transmitter

Explanation

Question 41 of 79

1

The basic idea behind Shannon-Fano coding is to

Select one of the following:

  • 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

Explanation

Question 42 of 79

1

Probability of occurrence of an event lies between

Select one or more of the following:

  • -1 and 0

  • 0 and 1

  • -1 and 1

  • exactly 1

Explanation

Question 43 of 79

1

The Hamming distance between "client" and "server" is

Select one of the following:

  • 0

  • 1

  • 6

  • impossible to detect

Explanation

Question 44 of 79

1

The Hamming distance between "make" and "made" is

Select one of the following:

  • 4

  • 3

  • 1

  • impossible to detect

Explanation

Question 45 of 79

1

The Hamming distance between "push" and "pull" is

Select one of the following:

  • 0

  • 4

  • 2

  • impossible to detect

Explanation

Question 46 of 79

1

Probability of second event in situation if first event has been occurred is classified as

Select one or more of the following:

  • conditional probability

  • joint entropy

  • conditional entropy

  • none of the given

Explanation

Question 47 of 79

1

The Hamming distance between "starting" and "finishing" is

Select one of the following:

  • 4

  • 3

  • impossible to detect

  • 5

Explanation

Question 48 of 79

1

The Hamming distance between 001111 and 010011 is

Select one of the following:

  • 1

  • 2

  • 3

  • 4

Explanation

Question 49 of 79

1

Shannon-Fano and Huffman codes are an encoding algorithms used for

Select one or more of the following:

  • lossy data compression

  • lossless data compression

  • error correction

  • error detection

Explanation

Question 50 of 79

1

The Hamming distance between 010111 and 010011 is

Select one of the following:

  • 2

  • 3

  • 1

  • 4

Explanation

Question 51 of 79

1

The Hamming distance between 011111 and 010011 is

Select one of the following:

  • 1

  • 3

  • 2

  • 4

Explanation

Question 52 of 79

1

Specify parts of the receiver side

Select one or more of the following:

  • Source encoder, channel encoder, digital modulator

  • Source decoder, channel decoder, digital demodulator

  • Source decoder, channel encoder, digital modulator

  • Source encoder, channel decoder, digital modulator

Explanation

Question 53 of 79

1

The Hamming distance between 101001 and 010011 is

Select one of the following:

  • 1

  • 2

  • 4

  • 3

Explanation

Question 54 of 79

1

The Hamming distance between two strings with equal length is ...

Select one of the following:

  • 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

Explanation

Question 55 of 79

1

Specify parts of the transmitter side

Select one or more of the following:

  • Source decoder, channel decoder, digital demodulator

  • Source encoder, channel encoder, digital modulator

  • Source decoder, channel encoder, digital modulator

  • Source encoder, channel decoder, digital modulator

Explanation

Question 56 of 79

1

The number of digits by which any two binary sequences differ is called the ...

Select one of the following:

  • Hamming weight

  • Hamming distance

  • Hamming code

  • Hamming length

Explanation

Question 57 of 79

1

Specify the case when entropy is maximum

Select one or more of the following:

  • p1=0,5 and p2=0,5

  • p1=1 and p2=0

  • p1=0 and p2=1

  • p1=0,9 and p2=0,1

Explanation

Question 58 of 79

1

The prefix code is also known as ...

Select one of the following:

  • block code

  • uniquely decodable code

  • convolutional code

  • parity bit

Explanation

Question 59 of 79

1

In a throw of dice what is the probability of getting number greater than 5.

Select one or more of the following:

  • a. 1/3

  • b. 1/6

  • c. 1/5

  • d. 1

Explanation

Question 60 of 79

1

The string was encoded with Hamming (15,11) code using the transformation matrix. Specify numbers of positions of the parity bits.

Select one of the following:

  • 12,13,14,15

  • 1,2,3,4

  • 1,2,4,8

  • 2,3,4,5

Explanation

Question 61 of 79

1

78. For a Hamming (31, 26) code, 31 is the total number of bits and 26 is the number of ...

Select one or more of the following:

  • a. redundant bits

  • b. data bits

  • c. parity bits

  • d. none of the given

Explanation

Question 62 of 79

1

The string was encoded with Hamming (31,26) code using the transformation matrix. Specify numbers of positions of the parity bits.

Select one of the following:

  • 27,28,29,30,31

  • 1,2,3,4,5

  • 1,2,4,8,16

  • 2,3,4,5,6

Explanation

Question 63 of 79

1

79. For a Hamming (7, 4) code, 7 is the total number of bits and 4 is the number of ...

Select one or more of the following:

  • a. redundant bits

  • b. data bits

  • c. parity bits

  • d. none of the given

Explanation

Question 64 of 79

1

When data is compressed, the goal is to reduce

Select one of the following:

  • noise

  • redundancy

  • channel capacity

  • none of the given

Explanation

Question 65 of 79

1

When the base of the logarithm is 10, then the unit of measure of information is

Select one of the following:

  • bytes

  • dits

  • nits

  • bits

Explanation

Question 66 of 79

1

43. Code has dmin = 3. How many errors can be detected by this code?

Select one or more of the following:

  • 1

  • 3

  • 2

  • 4

Explanation

Question 67 of 79

1

When the base of the logarithm is 2, then the unit of measure of information is

Select one of the following:

  • bytes

  • bits

  • nits

  • dits

Explanation

Question 68 of 79

1

When the base of the logarithm is e, then the unit of measure of information is

Select one of the following:

  • bytes

  • nits

  • dits

  • bits

Explanation

Question 69 of 79

1

Which block or device does the data compression?

Select one of the following:

  • Channel encoder

  • Source encoder

  • Modulator

  • None of the given

Explanation

Question 70 of 79

1

Which letter will get the shortest codeword after Huffman coding of the word "abracadabra"?

Select one of the following:

  • c

  • r

  • d

  • a

Explanation

Question 71 of 79

1

Which of the following codes has the highest code rate?

Select one of the following:

  • code rate is constant for all of the Hamming codes

  • Hamming (31,26)

  • Hamming (15,11)

  • Hamming (7,4)

Explanation

Question 72 of 79

1

Which of the following codes has the highest redundancy?

Select one of the following:

  • redundancy is constant for all of the Hamming codes

  • Hamming (7,4)

  • Hamming (15,11)

  • Hamming (31,26)

Explanation

Question 73 of 79

1

Which of the following codes is non-uniform?

Select one of the following:

  • Shannon-Fano

  • ASCII

  • Hamming

  • None of the given

Explanation

Question 74 of 79

1

Which of the following codes is prefix?

Select one of the following:

  • 0, 111, 11

  • 0, 111, 10

  • 0, 101, 10

  • 00, 10, 101

Explanation

Question 75 of 79

1

Which of the following codes is prefix?

Select one of the following:

  • 0, 01, 11

  • 0, 10, 11

  • 0, 10, 1

  • 0, 01, 001

Explanation

Question 76 of 79

1

Which of the following codes is uniform?

Select one of the following:

  • ASCII

  • Shannon-Fano

  • Huffman

  • None of the given

Explanation

Question 77 of 79

1

Which of the following codes is uniform?

Select one of the following:

  • 10,011,11,001,010

  • 0,10,110,1110,1111

  • 10,01,0001,100,1010

  • 100,110,001,000,010

Explanation

Question 78 of 79

1

Which of the following indicate(s) an error in a received combination?

Select one of the following:

  • Parity bits

  • Error syndrome

  • Data bits

  • None of the given

Explanation

Question 79 of 79

1

The string was encoded with Hamming (7,4) code using the transformation matrix. Specify numbers of positions of the parity bits.

Select one of the following:

  • a. 5,6,7

  • a. 1,2,3

  • a. 1,2,4

  • a. 2,3,4

Explanation

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