1, " ". , , , . . ( , -). . - ( ) .
.
, - I, . , I ( ). . .
, Xk,i n (i=1,n). . . .
k m. , . : . :
( ). ( ) () Yr,i, Xk,i ( ): .
Xk,i; Xk,i Yr,i .
Xk,i , Yr,i .
I = H(x) - H (x/y)
, () a ( ) . H(a), N :
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Pi , i - .
b, - ( b) ( ) H(a/b), . I(a) , b,
I (a) = H(a) H(a/b),
.. () .
H(a/b), , , I (a) = H(a). .
, , . . , N :
,
m, n, : M=mn .
. (). . , . . ( ). . , ,
M=mn ,
M ;
m ( , ),
n () .
m =2 . . - . : , 8 ; , 1024 ; , 1024 ..
N , . Q, , N ( ) Q = log2N.
. , "" "". , "" "", .
("" "") Q = log22 = 1.
(. bit binary digit ). , , , .
, 1 6 , 4 6. , 1/6. "" "", , 1/6 + 1/6 + 1/6 = 1/2 . , , .
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, . , . 4 12 . 4/(4+12) = 1/4, 12/(4+12) = 3/4.
: , .
I I= -log2p.
, I = -log2(1/4) = 2 , I = -log2(3/4) = 0,3 .
, ( ) () .
, , , .
, () .
, , , , , 128.
, , . ( , .)
N . Q=I ; Q Q = log2N.
N = 128 : Q= 7 .
, , Q.
, 0 1, .
1. , "" "". , ("" "") . , , 1 , , 1, "" 0, "" ( 0 "" 1 "").
2. , , . , 4- . ?
Q = log24 = 2 .
, (2 ), :
00 "" ;
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01 "" ;
10 "" ;
11 "" ;
, (), . , .
3. , , , 256. ( )?
2.16
ASCII- CP866
ASCII | ASCII | |
... | ... | ... |
... | ... | ... |
256 Q = log2256 = 8
, ( ) 8 . , . (.. ASCII-). . 2.16 ASCII- .