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WorksheetsИнфо Теория 14бет-27 бет
Total questions: 86
Worksheet time: 43mins
Shannon-Fano and Huffman codes are an encoding algorithms used for
lossy data compression
lossless data compression
error correction
error detection
Specify parts of the receiver side
Source encoder, channel encoder, digital modulator
Source decoder, channel decoder, digital demodulator
Source decoder, channel encoder, digital modulator
Source encoder, channel decoder, digital modulator
Specify parts of the transmitter side
Source decoder, channel decoder, digital demodulator
Source encoder, channel encoder, digital modulator
Source decoder, channel encoder, digital modulator
Source encoder, channel decoder, digital modulator
Specify the case when entropy is maximum
p1=0,5 and p2=0,5
p1=1 and p2=0
p1=0 and p2=1
p1=0,9 and p2=0,1
Specify the error position in the string "0000110", if the initial string was encoded with Hamming (7,4) code using the following structure (i1, i2, i3, i4, r1, r2, r3)
i1
i3
i4
i5
Specify the error position in the string "0001110", if the initial string was encoded with Hamming (7,4) code using the following structure (i1, i2, i3, i4, r1, r2, r3)
i4
i1
i2
r2
Specify the error position in the string "0011001", if the initial string was encoded with Hamming (7,4) code using the following structure (i1, i2, i3, i4, r1, r2, r3)
r2
r1
r3
i3
Specify the error position in the string "0101011", if the initial string was encoded with Hamming (7,4) code using the following structure (i1, i2, i3, i4, r1, r2, r3)
i1
i2
r2
r1
Specify the error position in the string "0101110", if the initial string was encoded with Hamming (7,4) code using the following structure (i1, i2, i3, i4, r1, r2, r3
r3
r2
i2
i3
Specify the error position in the string "0101111", if the initial string was encoded with Hamming (7,4) code using the following structure (i1, i2, i3, i4, r1, r2, r3
i1
i4
i3
r2
Specify the error position in the string "0110000", if the initial string was encoded with Hamming (7,4) code using the following structure (i1, i2, i3, i4, r1, r2, r3)
r1
r3
r2
i4
Specify the error position in the string "1010011", if the initial string was encoded with Hamming (7,4) code using the following structure (i1, i2, i3, i4, r1, r2, r3)
r1
no error
r2
r4
Specify the formula to calculate numbers of k and n bits to create the Hamming
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)
Specify the formula to find the amount of information if events have different probabilities.
Hartley's formula
Shannon's formula
Fano's formula
Bayes' formula
Specify the formula to find the amount of information if events have the same probabilities.
Shannon's formula
Hartley's formula
Fano's formula
Bayes' formula
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.
ASCII code
Shannon-Fano's code
Shannon-Fano's code by blocks
Hartley's code
Specify the right formula if dmin is Hamming distance, s - number of correctable errors and r - number of detectable errors.
dmin>= s+r+1
dmin>= ssff
dmin>= s+15
dmin>= s+r+Ul
Specify two types of error control algorithms
block and linear
linear and nonlinear
block and convolution
none of the given
Suppose the letters a, b, c, d, e, f have probabilities 1/2, 1/4, 1/8, 1/16, 1/32, 1/32 respectively. Which of the following is the Huffman code for the letter a, b, c, d, e, f?
11, 10, 011, 010, 001, 000
0, 10, 110, 1110, 11110, 11111
11, 10, 01, 001, 0001, 0000
110, 100, 010, 000, 001, 111
Suppose the letters a, b, c, d, e, f have probabilities 1/2, 1/4, 1/8, 1/16, 1/32, 1/32 respectively. What is the average length q of the Huffman code?
3,0
1,9
2,7
4,3
The amount of information in the message is 120 bits. Calculate the length of this message, which is written by characters of 16-character alphabet.
30
480
120
30
The amount of information in the message is 60 bits. Calculate the length of this message, which is written by characters of 4-character alphabet.
30
60
15
510
The basic idea behind Shannon-Fano coding is to
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
The efficiency of the language is 0,25 and its I average is 1 bit. Calculate the number of letters in this language's alphabet?
31
16
8
64
The Hamming distance between "client" and "server" is
0
1
6
impossible to detect
The Hamming distance between "make" and "made" is
4
3
1
impossible to detect
The Hamming distance between "push" and "pull" is
0
4
2
impossible to detect
The Hamming distance between "starting" and "finishing" is
4
3
impossible to detect
2
The Hamming distance between 001111 and 010011 is
1
2
3
4
The Hamming distance between 010111 and 010011 is
2
3
1
4
The Hamming distance between 011111 and 010011 is
1
3
2
4
The Hamming distance between 101001 and 010011 is
1
2
4
3
The Hamming distance between two strings with equal length is ...
the number of positions at which the corresponding symbols are different
the number of identical symbols in the first string
the number of positions at which the corresponding symbols are equal
the number of identical symbols in the second string
The length of the message is 16 symbols and the message's alphabet consists of 32 symbols. Find the amount of information in this message.
80
79
16
8
The length of the message is 6 symbols and the message's alphabet consists of 32 symbols. Find the amount of information in this message.
30
6
32
24
The number of digits by which any two binary sequences differ is called the ...
Hamming weight
Hamming distance
Hamming code
Hamming length
The prefix code is also known as ...
block code
uniquely dec
uniquely decodable code
convolutional code
parity bit
The redundancy of the language is 0,75 and its I average is 1 bit. Calculate the number of letters in this language's alphabet?
32
16
8
2
The string was encoded with Hamming (15,11) code using the transformation matrix. Specify numbers of positions of the parity bits.
12,13,14,15
1,2,3,4
1,2,4,8
2,3,4,5
The string was encoded with Hamming (31,26) code using the transformation matrix. Specify numbers of positions of the parity bits.
27,28,29,30,31
1,2,3,4,5
1,2,4,8,16
2,3,4,5,6
The string was encoded with Hamming (7,4) code using the structure (i1, i2, i3, i4, r1, r2, r3). After a channel the error syndrome is 000. Specify the position of the error.
i1
r1
no error
r2
The string was encoded with Hamming (7,4) code using the structure (i1, i2, i3, i4, r1, r2, r3). After a channel the error syndrome is 001. Specify the position of the error.
i1
r1
r3
no error
The string was encoded with Hamming (7,4) code using the structure (i1, i2, i3, i4, r1, r2, r3). After a channel the error syndrome is 010. Specify the position of the error.
r3
r1
r2
i2
The string was encoded with Hamming (7,4) code using the structure (i1, i2, i3, i4, r1, r2, r3). After a channel the error syndrome is 011. Specify the position of the error.
I2
i4
R3
R2
The string was encoded with Hamming (7,4) code using the structure (i1, i2, i3, i4, r1, r2, r3). After a channel the error syndrome is 100. Specify the position of the error.
r3
i1
r1
r3
The string was encoded with Hamming (7,4) code using the structure (i1, i2, i3, i4, r1, r2, r3). After a channel the error syndrome is 101. Specify the position of the error.
no error
r1
i1
i2
The string was encoded with Hamming (7,4) code using the structure (i1, i2, i3, i4, r1, r2, r3). After a channel the error syndrome is 110. Specify the position of the error.
i3
i4
i2
r2
The string was encoded with Hamming (7,4) code using the structure (i1, i2, i3, i4, r1, r2, r3). After a channel the error syndrome is 111. Specify the position of the error.
i4
r2
i2
i4
The string was encoded with Hamming (7,4) code using the transformation matrix. Specify numbers of positions of the parity bits.
5,6,7
1,2,3
1,2,4
2,3,4
What is the probability of getting a sum 9 from two throws of dice.
1/3
1/9
1/12
2/9
When data is compressed, the goal is to reduce
noise
redundancy
channel capacity
none of the given
When data is compressed, the goal is to reduce
noise
channel capacity
redundancy
none of the given
When the base of the logarithm is 10, then the unit of measure of information is
bytes
dits
nits
bits
When the base of the logarithm is 2, then the unit of measure of information is
bytes
bits
nits
dits
When the base of the logarithm is e, then the unit of measure of information is
bytes
nits
dits
bits
Which block or device does the data compression?
Channel encoder
Source encoder
Modulator
None of the given
Which letter will get the shortest codeword after Huffman coding of the word "abracadabra"?
c
r
a
d
Which of the following codes can be the Huffman code for the letters a,b,c,d,e?
10,011,11,001,010
0,10,110,1110,1111
10,01,0001,100,1010
100,110,001,000,010
Which of the following codes has the highest code rate? code rate is constant for all of the Hamming codes
Hamming (31,26)
Hamming (15,11)
Hamming (7,4)
Which of the following codes has the highest redundancy? redundancy is constant for all of the Hamming codes
Hamming (7,4)
Hamming (15,11)
Hamming (31,26)
Which of the following codes is non-uniform?
Shannon-Fano
ASCII
Hamming
None of the given
Which of the following codes is prefix?
0, 111, 10
0,101,11
11,000,10
0,011,11
Which of the following codes is prefix?
0, 01, 11
0, 10, 11
0, 10, 1
0, 01, 001
Which of the following codes is uniform?
ASCII
Shannon-Fano
Huffman
None of the given
Which of the following codes is uniform?
10,011,11,001,010
0,10,110,1110,1111
10,01,0001,100,1010
100,110,001,000,010
Which of the following indicate(s) an error in a received combination?
Parity bits
Error syndrome
Data bits
None of the given
Which of the following is a part the channel coding?
Huffman code
Hamming code
Shannon-Fano code
RLE code
Which of the following is a part the source coding?
Hamming code
Huffman code
Error-correcting code
Convolutional code
Which of the following is not a correct statement about a probability.
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
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?
c
a
b
d
______ indicate(s) an error in a received combination.
Parity bits
Error syndrome
Data bits
None of the given
... is a measure of uncertainty
Encoding
Entropy
Information
Redundancy
A code has two allowable combinations 101 and 010. Not for the error combination 001?
101
110
No error
011
A code has two allowable combinations 101 and 010. What is the allowable combination for the error combination 100?
101
010
100
None
A code has two allowable combinations 101 and 010. What is the allowable combination for the error combination 000?
010
101
000
None
A code has two allowable combinations 101 and 010. What is the allowable combination for the error combination 111?
101
010
100
None
A code has two allowable combinations 101 and 010. What is the allowable combination for the error combination 011?
010
100
111
none
A code has two allowable combinations 101 and 010. What is the allowable combination for the error
combination 110?
010
101
111
None
A codeword of the Hamming code consists of ________ and ________ bits.
data; parity
with errors; without errors
allowable; not allowable
none of the given
A Huffman code is a = 1, b = 000, c = 001, d = 01. Probabilities are p(a) = 0.4, p(b) = 0.1, p(c) = 0.2, p(d) = 0.3. The average length of codewords q is
2.1 bit
1.9 bit
2.0 bit
8.0 bit
A redundancy of a code S = ...
1 - Iavr/Imax
Iavr/Imax
1 + Iavr/Imax
Imax/Iavr
An average length of codewords qavr = ...
∑ (pi*qi)
∑ (pi/qi)
∑pi / n
An efficiency of a code E = ...
Iavr/Imax
Imax/Iavr
Iavr/100
Imax - Iavrprefix
ASCII code is a
Variable length code
Fixed length code
Error-correction code
None of the given
By the Bayes' rule for conditional entropy H(Y|X) = ...
H(X|Y) - H(X) + H(Y)
P(A)] /P(B)
H(X|Y) - H(X)
H(X|Y)+ H(Y)
By the Bayes' theorem ...
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)
