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dt ¼ X
N
n i
d
a ijk n j ð t Þn k ð t Þþ b ij n j ð t Þ
ð 2
:
35 Þ
k ; j¼1
Putting the initial conditions as
n i ðÞ i ¼ 1
ð
; ...;
N
Þ
ð 2
:
36 Þ
the reconstruction task of
ʾ i (t) for the arbitrary time t
[0,T] comes down to the
simple task of determining unknown coef
cients based on the criterion:
(
)
E ¼ X
X
M
N
i¼1 n i ð t s Þn i ð t s Þ
2
½
=
N
=
M
ð 2
:
37 Þ
s¼1
where 0 t 1 t M T.
Coef
cients {a ijk ,b ij ) can be evaluated as solution of the following optimization
task:
E 0 ¼
min
a ijk ; b ij ;n i ð 0 Þ
E
ð 2
:
38 Þ
f
g
There are many methods to solve this task. One of them is based on the
Bellman
s dynamic programming method (Bellman and Roth 1966; Krapivin and
Kondratyev 2002; Krapivin 1969; Ram 2010). In this case search of minimal value
of function E comes to the dynamic programming task. Let us supposed that
coef
'
cients {a ijk ,b ij ) are functions of time:
n 1 ð t Þ
.
n N ð t Þ
a 111 ð t Þ
.
a NNN ð t Þ
b 11 ð t Þ
.
b NN ð t Þ
Y ð t Þ ¼
ð 2
:
39 Þ
We can consider that a ijk =a ikj . Then addicting the system ( 2.35 ) Cauchy
problem ( 2.35 ), ( 2.36 ) comes to the following task:
dY
=
dt ¼ G ðÞ
ð 2
:
40 Þ
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