: I V
. (. 1.4).
. 1.4.
. , .
V, () . :
1) (bit binary digit ). - ( ; λ 1), . , , , , .
. , . , 256 (256=28).
:
1 () = 1024
1 () = 1024
1 () = 1024
, :
/ () = 1024
1 () = 1024
2) , , , . (), () .
I ( ). , - , .. () . .
, . (1928 .) N , /, , N. :
I = log2N 2I = N.
N= 2 ( ), I = 1 .
. N = I/N, N = 1/
I=iog2(1/p)=-log2p.
, . , : / = Iog2100 = 6,644. , 6,644 .
|
|
: : , ; : , .
, . . , . , , , , , , .
1948 . , .
:
I=-(p1 Iog2 p1 +p2 Iog2p2 +... +pNlog2pN),
I
pi , i-e N .
, p1,..., pN , 1/N, .
. () α. (α), .
β I β(α), , ( β) H β(α).
I β(α) , β, :
I β(α) = H (α) - H β(α)
.. () .
H β(α) , I β(α) = H (α). , H (α) .
H (α), N , , :
Pi , i- .
, , .. Pi = 1/N,
, . , ,
N=mn
N ;
( , );
() .
. - , . ' N = n, , , , I= log N = n log . , I=n. ( ) I = V, . I < V =n.
|
|
. .
() () , ..
Y= I/V, 0 < Y < 1
Y () , , .
. , .. , , . .
, .
S Sp Ic . . 1.5. , Ic 0:
1) Sp = 0 , ;
2) Sp = ∞ , .
Ic S Sp (Sp = Sp opt), ( ) .
, , , , . ( ) .
. 1.5. , ,
Ic=f(SP)
() S Sp.
, .
. . - , .
, :
Inβ(γ)=(γ/)-(γ),
Inβ(γ) β γ,
(γ) ,
(γ/)- γ , , β.
. 1.1.
|
|
1.1.