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u
n
icatio
n
s
s
y
s
te
m
to
r
ec
o
g
n
ize
t
h
e
t
y
p
e
o
f
m
o
d
u
lat
io
n
an
d
d
e
m
o
d
u
latio
n
[
2
]
I
n
th
e
m
id
an
d
late
o
f
th
e
1
9
8
0
s
,
t
w
o
i
m
p
o
r
tan
t
w
a
y
s
o
f
AR
T
,
w
h
ic
h
led
to
a
s
ig
n
i
f
ica
n
t d
ev
elo
p
m
e
n
t
in
t
h
i
s
ar
ea
.
T
h
ese
t
w
o
m
et
h
o
d
s
ar
e
th
e
d
ec
is
io
n
th
eo
r
etic
a
p
p
r
o
ac
h
(
DT
)
an
d
th
e
s
tatic
p
atter
n
(
SP
)
an
d
b
o
th
m
et
h
o
d
s
d
ep
en
d
o
n
g
u
es
s
in
g
a
s
ep
ar
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n
alg
o
r
ith
m
an
d
ch
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o
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e
th
e
ap
p
r
o
p
r
i
ate
th
r
esh
o
l
d
s
f
o
r
th
e
m
[
5
,
6
]
.
I
t
is
n
o
ted
h
er
e
t
h
at
i
f
th
e
s
e
th
r
es
h
o
ld
s
ar
e
n
o
t
s
elec
ted
v
er
y
p
r
ec
is
el
y
,
th
is
w
i
ll
r
esu
lt
in
a
d
ec
r
ea
s
e
i
n
th
e
alg
o
r
it
h
m
p
er
f
o
r
m
a
n
ce
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es
p
ec
iall
y
w
h
e
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th
e
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o
i
s
e
is
p
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esen
t,
s
o
t
h
er
e
is
a
n
ee
d
to
f
in
d
o
th
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m
et
h
o
d
s
to
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ec
o
g
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ize
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h
e
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y
p
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o
f
m
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lati
o
n
th
at
i
s
b
etter
p
er
f
o
r
m
in
g
ev
en
w
it
h
n
o
is
e.
Sin
ce
th
e
b
eg
i
n
n
in
g
o
f
t
h
e
1
9
9
0
s
[
7
,
8
]
,
th
er
e
h
as
b
ee
n
o
r
ien
ted
to
w
ar
d
s
i
n
d
u
s
tr
ial
i
n
t
ellig
e
n
ce
i
n
th
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g
en
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al
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g
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i
tio
n
a
n
d
cl
ass
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tio
n
p
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ce
s
s
es,
w
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h
h
as
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lo
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it
to
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s
ed
to
r
e
co
g
n
ize
th
e
t
y
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es
o
f
m
o
d
u
latio
n
.
T
h
is
s
tep
h
as
g
r
ea
tl
y
i
m
p
r
o
v
ed
th
e
p
er
f
o
r
m
an
ce
o
f
th
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s
y
s
te
m
th
a
n
it
w
a
s
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esp
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iall
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i
n
th
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esen
ce
o
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n
o
is
e.
Mo
s
t
o
f
th
e
p
r
ev
io
u
s
l
y
p
r
o
p
o
s
ed
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et
h
o
d
s
w
er
e
d
esi
g
n
ed
to
r
ec
o
g
n
ize
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alo
g
m
o
d
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lat
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n
m
et
h
o
d
s
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b
u
t
r
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en
t
co
n
tr
ib
u
ti
o
n
s
an
d
r
esear
c
h
es
o
n
th
i
s
s
u
b
j
ec
t
ar
e
m
o
r
e
f
o
cu
s
ed
o
n
d
ig
it
al
co
m
m
u
n
icatio
n
s
b
ec
au
s
e
o
f
t
h
e
in
cr
ea
s
in
g
u
s
e
o
f
d
ig
ital
m
o
d
u
latio
n
[
8
,
9
]
.
Mo
s
t
o
f
th
e
e
x
i
s
ti
n
g
A
R
T
o
f
th
e
m
o
d
u
latio
n
t
y
p
e
ca
n
r
ec
o
g
n
ize
an
d
c
lass
if
y
a
f
e
w
t
y
p
e
s
o
f
d
i
g
it
a
l
m
o
d
u
latio
n
m
et
h
o
d
s
[
8
]
.
Mo
s
t
o
f
w
h
ic
h
ca
n
d
eter
m
i
n
e
th
e
t
y
p
e
o
f
d
ig
ita
l
m
o
d
u
latio
n
f
r
o
m
s
i
g
n
al
s
w
ith
h
ig
h
SNR
,
b
u
t
w
ith
i
n
cr
ea
s
i
n
g
t
h
e
n
o
is
e,
th
e
r
esu
l
ts
w
ill
b
e
w
o
r
s
t
an
d
th
e
s
y
s
te
m
th
e
n
w
ill
b
e
u
n
ab
le
to
d
eter
m
i
n
e
th
e
t
y
p
e
o
f
d
ig
ital
m
o
d
u
latio
n
.
T
h
e
i
m
p
o
r
tan
ce
o
f
th
is
r
esear
ch
is
to
ad
ap
t
a
r
tif
icial
in
te
lli
g
en
ce
to
p
r
o
p
o
s
e
an
AR
T
s
y
s
te
m
ca
p
ab
le
o
f
r
ec
o
g
n
izin
g
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d
cla
s
s
i
f
y
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n
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m
a
n
y
d
i
f
f
er
en
t
t
y
p
es
o
f
d
ig
i
tal
m
o
d
u
lati
o
n
m
et
h
o
d
s
.
Usi
n
g
an
A
r
t
if
ic
ial
Neu
r
al
Net
w
o
r
k
w
i
th
it
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co
m
p
lex
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g
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r
ith
m
is
t
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cr
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a
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m
m
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o
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s
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ev
en
w
it
h
s
i
g
n
a
ls
o
f
lo
w
SN
R
.
2.
RE
S
E
ARCH
AIM
T
h
is
p
ap
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d
ep
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s
o
n
th
e
co
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to
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ti
m
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ap
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s
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d
f
o
llo
w
ed
t
h
e
f
o
llo
w
in
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m
et
h
o
d
o
lo
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y
:
-
Stu
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y
a
n
d
a
n
al
y
ze
t
h
e
t
y
p
es o
f
d
ig
ital
m
o
d
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latio
n
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n
d
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tu
d
y
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-
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n
v
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ti
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t i
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tu
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d
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tec
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iq
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-
An
al
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p
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th
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-
T
h
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estab
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h
m
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t
o
f
th
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ar
t
if
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n
eu
r
al
n
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w
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r
k
(
A
NN
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,
w
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w
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s
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ar
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th
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d
a
lo
w
v
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lu
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-
T
esti
n
g
t
h
e
A
NN.
3.
M
O
DULAT
I
O
N
M
E
T
H
O
DS U
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U
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[
2
,
1
0
]
.
W
h
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g
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w
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[
1
1
]
.
T
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Fig
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3
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ig
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r
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o
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ig
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e
o
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h
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b
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u
r
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4
.
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ital
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o
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th
e
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Fig
u
r
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5
.
Dig
ital
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e
o
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SK
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.
4
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O
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o
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l Q
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M
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ates t
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6
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D
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f
o
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p
h
ase
[
2
,
1
2
-
1
4
]
.
Fig
u
r
e
7
.
Ke
y
f
ea
t
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T
h
e
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h
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ate
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asic
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ita
l
m
o
d
u
latio
n
m
et
h
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d
s
(
6
4
QA
M
,
2
P
SK,
4
P
SK,
8
P
SK,
4
A
SK,
2
FS
K,
4
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8
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T
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1
.
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1
2
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4
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2
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[
1
2
]
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
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8
8
-
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I
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t J
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&
C
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p
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Vo
l.
10
,
No
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6
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Dec
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b
er
2
0
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5
8
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8
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2
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4
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3
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(
3
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K
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ir
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k
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th
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s
ta
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d
ar
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d
ev
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f
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o
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m
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m
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s
[
1
4
]
.
=
√
1
(
∑
2
(
)
(
)
>
)
−
1
(
∑
|
(
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|
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2
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w
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(
6
4
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,
4
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is
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4
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(
6
4
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M)
[
1
4
]
.
T
h
e
th
ir
d
k
e
y
:
(
)
Stan
d
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d
d
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t
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[
1
4
]
.
=
√
1
(
∑
2
(
)
(
)
>
)
−
1
(
∑
|
(
)
|
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2
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6
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T
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e
f
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k
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:
(
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T
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s
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ev
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f
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1
4
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ca
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eter
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ed
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y
[
1
4
]
:
Evaluation Warning : The document was created with Spire.PDF for Python.
I
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1
4
]
.
5.
ARTI
F
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CIA
L
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Fo
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3
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3
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1
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1
6
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1
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]
.
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ith
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as s
h
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ig
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r
e
8
.
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m
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f
w
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ts
o
p
ti
m
izati
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to
g
et
a
s
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le
s
tate
th
at
m
a
k
es
t
h
e
n
et
w
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r
k
p
r
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e
s
p
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to
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atter
n
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v
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g
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s
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tr
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t
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t
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t
h
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h
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p
r
ed
eter
m
i
n
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d
(
s
ee
F
ig
u
r
e
8
)
.
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n
th
is
p
ap
er
,
th
e
p
r
ev
io
u
s
eig
h
t
f
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t
u
r
es
u
s
ed
to
b
u
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th
e
p
a
tter
n
s
v
ec
to
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.
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h
e
p
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n
s
v
ec
to
r
w
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s
g
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t
f
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m
th
e
co
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d
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e
k
e
y
f
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u
r
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f
r
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m
a
n
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y
m
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d
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s
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n
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a
s
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th
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cr
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co
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h
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n
el,
a
n
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s
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v
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er
v
ec
to
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w
h
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h
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t
h
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tar
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et
s
v
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to
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.
T
h
e
n
eu
r
al
n
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w
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k
was
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r
o
u
g
h
t
h
e
p
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n
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d
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to
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s
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g
et
th
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ab
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p
r
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f
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r
th
is
ap
p
licatio
n
[
1
9
-
2
5
].
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
0
8
8
-
8708
I
n
t J
E
lec
&
C
o
m
p
E
n
g
,
Vo
l.
10
,
No
.
6
,
Dec
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b
er
2
0
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Fig
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6.
RE
SU
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S AN
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SCU
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MA
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B
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