, .
,.
. (,,, -, ), - .
:,.ʳ.,--, .,, ,,, ..
.俿, , - .
,09,-0 1,-0 7, - 0 9 A,B,C,D,E,F.9.1.
1-
³ | س | ||
0A | |||
0B | |||
0C | |||
0D | |||
0E | |||
0F | |||
.
. n - (), L - . () L = 2. г , (, ).
, ' , :
1. ' ;
2. () , .
, , .
x = { xi }, i = 1, 2,..., N - p (xi), ay = { yk }, k = 1, 2,..., L - L <N, n M = Ln.
|
|
Ln ≥ N, n - , .
1 - N = 24 :
_ - __
г. ni pi =
x _ -
n 2 6 2 1 2 2 2 1 1 1 3 1
p 0.08 0.25 0.08 0.04 0.08 0.08 0.08 0.04 0.04 0.04 0.15 0.04
-H (x) = pilnpi=+ 0.08 ln 0.08 + 0.08 ln 0.08 + 0.08 ln 0.08 + 0.04 ln 0.04 + 0.04 ln 0.04 +
=+0.08 ln 0.08 + 0.25 ln 0.25 + 0.08ln 0.08 + 0.04 ln 0.04 ++ 0.04 ln 0.04 + 0.15 ln 0.15 + 0.04 ln 0.04 ∼ 3.3.
:
x _ -
p 0.25 0.15 0.08 0.080.08 0.08 0.08 0.04 0.04 0.04 0.040.04
' , . 0, 1.
0,44 | 0.56 | ||||||||||
_ | - | ||||||||||
0,25 | 0,15 | 0,08 | 0,08 | 0,08 | 0,08 | 0,08 | 0,04 | 0,04 | 0,04 | 0,04 | 0,04 |
, -
0, - 1 ...
_ | - | |||||||||||
0,25 | 0,15 | 0,08 | 0,08 | 0,08 | 0,08 | 0,08 | 0,04 | 0,04 | 0,04 | 0,04 | 0,04 | |
'
_ | |||||
- |
- , , ﳿ . 3 (, _, , ) 4 - 8- .
_ | 1/3 | 2/3 |
,
() = 3*1/3 + 4*2/3 = 3.67
S=H (x)/() = 3.3/3.67=0.899.
,
ﳿ, S = 1.
', , , .
0 1. :
0+0=0, 0+1=1, 1+0=1, 1+1=0; | 0*0=0, 0*1=0, 1*0=0, 1*1=1. |
2 (mod 2). mod 2, , Å
|
|
, 0101101
⊕1001010
, - , . .
9.2.
- | ASCII | ||
31 30 | |||
31 31 | |||
31 32 | |||
31 33 | |||
31 34 | |||
31 35 |
.
: N = 2n,
n - .
, -. , (0111 - 1000). , , ,
, , , - 1.
() .
2 , . ϳ .
ASCII . - .
, . :
-
-
,
. , (). "m" (1101101) "o" (1101111) 1. "a" (1100001) "z" (1111010) 4. . - (00000).
, ( 2: ⊕).
:
d = 1 ;
d = 2;
d =3.
:
d=r + s + 1,
r -, ;
s -, .
, d =3,,, .
. 2,-3, - 4, - 5.
,2, :
k 4 k 3 k 2 m 3 k 1 m 2 m 1; (9.3)
k -;
m -().
2-:
|
|
. bi, ai. , :
-
m 3 | m 2 | m 1 | ||
m1 | 1 = 1⊕2⊕4 1 = 1⊕3⊕4 2= 2⊕3⊕4 | |||
m 2 | ||||
k 1 | ||||
m 3 | ||||
k 2 | ||||
k 3 | ||||
k 4 |
.. a0 k 1= 1. k 2-
k 2 1 = 1, ..
[7, 4],
( 1, 2, 1, 3, 2, 3, 4
:
A0 = b1⊕ b2⊕ b4
A1 = b1⊕ b3⊕ b4
A2 = b2⊕ b3⊕ b4
ai Ai -
.
M = 20 (a0⊕ A0) + 21 (a1⊕ A1) + 22 (a2⊕ A2).
3.1 (1010).
. k = 4 ,
2r ≥ k + r + 1, 23 = 8 ≥ 4 + 3 + 1 = 8,
.. n = k + r = 4 + 3 = 7. r = 3,
[n, k] = [7, 4] (a0, a1, b1, a2, b2, b3, b4). ,
(b1, b2, b3, b4) = (1010),
a0 = b1⊕ b2⊕ b4 = 1 ⊕ 0 ⊕ 0 = 1
a1 = b1⊕ b3⊕ b4 = 1 ⊕ 1 ⊕ 0 = 0
a2 = b2⊕ b3⊕ b4 = 0 ⊕ 1 ⊕ 0 = 1
(a0, a1, b1, a2, b2, b3, b4) = (1011010).
3.2. (0101101)
. .
.
(a0, a1, b1, a2, b2, b3, b4) = (1101101).
, b1 = 0, b2 = 1, b3 = 0,b4 = 1
A0 = b1⊕ b2⊕ b4 = 0 ⊕ 1 ⊕ 1 = 0
A1 = b1⊕ b3⊕ b4 = 0 ⊕ 0 ⊕ 1 = 1
A2 = b2⊕ b3⊕ b4 = 1 ⊕ 0 ⊕ 1 = 0
ai Ai
M = 20 (a0⊕ A0) + 21 (a1⊕ A1) + 22 (a2⊕ A2)
= 20 (1 ⊕ 0) + 21 (1 ⊕ 1) + 22 (1 ⊕ 0)
= 20 1 + 21 0 + 22 1 = 5.
5- (1101101) -
,
(1101101) → (1101001).
,
b1 = 0,b2 = 0,b3 = 0, b4 = 1, (0001).