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s
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tio
n
w
a
s
a
tr
en
d
[
6
]
.
W
eb
2
.
0
to
o
ls
ar
e
m
o
r
e
lik
el
y
in
ter
ested
in
cr
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tin
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m
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e
co
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w
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s
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u
ilt
to
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ec
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m
i
cr
o
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ten
t
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d
s
h
ar
e
i
n
ter
est;
Ne
w
tr
e
n
d
s
ap
p
ea
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ed
s
h
a
r
in
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p
h
o
to
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ip
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tag
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u
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co
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au
t
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2
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2
.
E
-
l
ea
rning
E
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lear
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ca
m
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1
9
9
0
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alo
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h
d
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W
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id
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W
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b
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ter
est
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as
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h
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s
d
is
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s
io
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s
.
T
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“
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th
at
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ten
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ed
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p
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[
7
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Ma
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l
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r
n
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av
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ee
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p
r
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p
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s
ed
[
8
]
,
Go
o
d
y
ear
(
2
0
0
0
)
d
ef
in
ed
e
-
lear
n
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as
t
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m
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s
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lti
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;
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m
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E
-
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B
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x
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d
is
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t
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m
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en
t
q
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ased
co
r
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tio
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h
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ter
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in
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an
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o
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w
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p
lace
s
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g
s
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T
h
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tu
d
en
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s
th
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ce
n
ter
o
f
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l
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r
n
in
g
s
y
s
te
m
[
9
]
,
h
e
ca
n
p
r
esen
t
m
a
n
y
b
en
e
f
it
s
f
o
r
lear
n
er
s
:
a.
Of
f
er
s
co
m
p
le
te
f
lex
ib
ilit
y
v
is
-
à
-
v
i
s
t
h
e
ti
m
e
a
n
d
lo
ca
tio
n
c
o
n
s
tr
ain
ts
.
«
j
u
s
t
i
n
ti
m
e
-
a
n
y
ti
m
e
ap
p
r
o
ac
h
(
R
o
s
em
b
er
g
,
2
0
0
1
)
;
b.
A
llo
w
s
u
s
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o
f
m
u
l
ti
m
ed
ia
co
n
ten
t,
e
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ce
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c.
Of
f
er
s
a
p
er
s
o
n
alize
d
lear
n
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n
g
[
1
0
]
d.
Of
f
er
s
t
h
e
p
o
s
s
ib
ilit
y
to
cr
ea
te
lear
n
er
s
co
m
m
u
n
it
y
t
h
at
allo
w
s
d
ialo
g
u
e
s
a
n
d
i
n
f
o
r
m
atio
n
ex
ch
a
n
g
e
b
et
w
ee
n
lear
n
er
s
o
r
b
et
w
ee
n
lear
n
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s
-
teac
h
er
s
[
1
1
]
2
.
3
.
M
o
o
cs
Ma
s
s
i
v
e
o
p
en
o
n
lin
e
co
u
r
s
e
s
(
MO
OC
s
)
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th
e
n
e
w
p
h
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n
o
m
e
n
o
n
t
h
at
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s
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lu
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r
em
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(
Fi
g
u
r
e
1
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,
th
e
ter
m
em
er
g
ed
in
2
0
0
8
b
u
t
h
av
e
r
ec
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lar
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tr
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m
m
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c
e
2
0
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2
,
"
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also
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p
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all
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ts
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T
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e
ter
m
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Op
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d
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t
th
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t
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m
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n
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eq
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to
p
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On
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f
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o
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g
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tact
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n
ad
d
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n
to
th
e
v
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tu
a
l
[
1
2
]
.
"
C
o
u
r
s
es"
d
ef
in
es
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n
ad
d
itio
n
to
d
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is
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g
r
u
d
i
m
en
tar
y
ca
lc
u
latio
n
s
e
n
ab
led
th
e
m
p
r
ed
ictio
n
s
s
u
c
h
as h
o
w
lo
n
g
th
e
ir
f
o
o
d
s
u
p
p
lie
s
w
o
u
ld
last
[
1
3
]
.
W
ith
th
e
e
x
p
an
s
io
n
o
f
s
to
r
ag
e
tech
n
o
lo
g
ies
a
n
d
th
e
e
m
er
g
e
n
ce
o
f
w
eb
2
.
0
ea
ch
an
d
ev
er
y
o
n
e
o
f
u
s
is
co
n
s
ta
n
tl
y
p
r
o
d
u
cin
g
a
n
d
r
elea
s
in
g
d
ata,
ac
co
r
d
in
g
to
I
B
M
9
0
%
o
f
th
e
d
ata
in
th
e
w
o
r
ld
to
d
ay
h
a
s
b
ee
n
cr
ea
te
d
in
t
h
e
last
t
w
o
y
ea
r
s
a
l
o
n
e.
T
h
is
d
ata
co
m
e
f
r
o
m
ev
er
y
w
h
er
e:
p
o
s
ts
o
n
s
o
cial
m
ed
ia
,
s
ec
u
r
it
y
ca
m
er
as,
ce
ll
p
h
o
n
e
GP
S
s
ig
n
al,
co
m
m
er
cial
tr
an
s
ac
tio
n
s
,
b
u
s
i
n
es
s
d
ata.
T
h
e
T
a
b
le
1
b
elo
w
li
s
ts
t
h
e
m
ain
B
ig
Dat
a
o
r
ig
in
d
o
m
ain
s
a
n
d
tar
g
eted
u
s
e
o
r
ap
p
licatio
n
,
li
s
t
n
o
t e
x
h
a
u
s
ti
v
e,
w
h
ic
h
il
lu
s
tr
ate
t
h
at
b
i
g
d
ata
ar
e
p
r
ese
n
t i
n
ev
er
y
d
o
m
ai
n
[
1
4
]
.
T
ab
le
1
.
B
ig
d
ata
Or
ig
in
a
n
d
t
ar
g
et
u
s
e
d
o
m
a
in
s
B
i
g
d
a
t
a
O
r
i
g
i
n
B
i
g
D
a
t
a
T
a
r
g
e
t
U
se
1
.
S
c
i
e
n
c
e
2
.
T
e
l
e
c
o
m
3
.
I
n
d
u
s
t
r
y
4
.
S
o
c
i
a
l
me
d
i
a
a
n
d
n
e
t
w
o
r
k
s
5
.
L
i
v
i
n
g
E
n
v
i
r
o
n
me
n
t
,
C
i
t
i
e
s
6
.
H
e
a
l
t
h
c
a
r
e
a
.
S
c
i
e
n
t
i
f
i
c
d
i
s
c
o
v
e
r
y
b
.
N
e
w
t
e
c
h
n
o
l
o
g
i
e
s
c
.
M
a
n
u
f
a
c
t
u
r
i
n
g
,
p
r
o
c
e
ss c
o
n
t
r
o
l
,
t
r
a
n
sp
o
r
t
d
.
P
e
r
so
n
a
l
se
r
v
i
c
e
s,
c
a
m
p
a
i
g
n
s
e
.
L
i
v
i
n
g
e
n
v
i
r
o
n
me
n
t
s
u
p
p
o
r
t
f
.
H
e
a
l
t
h
c
a
r
e
su
p
p
o
r
t
E
v
en
if
b
ig
d
ata
is
t
h
e
n
e
w
b
u
zz
-
w
o
r
d
th
er
e
i
s
n
o
ex
ac
t
d
ef
i
n
itio
n
,
alt
h
o
u
g
h
s
cie
n
ti
f
ic
p
ap
er
d
escr
ib
e
b
ig
d
ata
as h
a
v
in
g
5
V
p
r
o
p
er
ti
es:
2
.
4
.
1
.
Vo
lu
m
e
R
ef
er
s
to
th
e
v
as
t
a
m
o
u
n
t
o
f
d
ata
g
en
er
ated
,
n
e
w
u
n
it
ar
e
b
ein
g
co
m
m
o
n
l
y
u
s
ed
,
th
e
wo
r
ld
is
n
o
w
talk
i
n
g
ab
o
u
t
P
eta
b
y
tes
an
d
Z
ettab
y
tes
w
h
ic
h
ar
e
s
u
cc
e
s
s
i
v
el
y
1
0
15
b
y
tes
a
n
d
1
0
21
b
y
tes
[
1
5
]
,
Face
b
o
o
k
h
as
2
.
5
P
B
o
f
u
s
er
d
ata
(
2
0
0
9
)
,
e
B
ay
h
as
6
.
5
P
B
o
f
u
s
er
d
ata
(
2
0
0
9
)
,
f
ac
t
th
at
m
a
k
es
m
o
s
t
d
atasets
to
o
lar
g
e
to
s
to
r
e
an
d
an
al
y
ze
u
s
i
n
g
tr
ad
it
io
n
al
d
atab
ase
tech
n
o
lo
g
y
.
D
i
s
tr
ib
u
ted
s
y
s
te
m
d
is
lo
ca
ted
ar
o
u
n
d
th
e
w
o
r
ld
ar
e
u
s
ed
to
s
to
r
e
an
d
an
al
y
ze
d
ata
[
16
].
2
.
4
.
2.
Velo
cit
y
T
h
e
v
elo
cit
y
ch
ar
ac
ter
is
t
ic,
r
ef
er
s
to
th
e
s
p
ee
d
o
f
w
h
ic
h
n
e
w
d
ata
is
cr
ea
ted
,
an
d
th
e
s
p
e
ed
o
f
w
h
ic
h
d
ata
is
d
eliv
er
ed
.
No
w
-
a
-
d
a
y
s
f
lo
w
o
f
d
ata
is
e
n
o
r
m
o
u
s
an
d
co
n
tin
u
o
u
s
,
f
o
r
tu
n
atel
y
ac
tu
al
tec
h
n
o
lo
g
y
d
o
allo
w
an
a
l
y
zi
n
g
d
ata
w
h
ile
it
's
cr
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ted
,
ca
lled
it
in
-
m
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m
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al
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tic
s
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in
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p
r
o
ce
s
s
o
f
s
to
r
i
n
g
it i
n
to
d
atab
ases
.
No
SQ
L
(
No
t O
n
l
y
S
QL
)
is
a
n
ec
lectic
a
n
d
in
cr
ea
s
i
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g
l
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f
a
m
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g
r
o
u
p
0
20
00
40
00
60
00
20
12
20
13
20
14
20
15
20
16
G
r
owth
of
MOO
Cs
Cou
rs
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Va
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ce
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f
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er
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t
f
o
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m
at
s
a
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ca
n
co
n
ta
in
m
u
ltid
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en
s
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al
d
ata
f
ield
,
s
o
w
e
ca
n
d
is
ti
n
g
u
e
d
if
f
e
r
en
t
t
y
p
e
s
:
Str
u
ct
u
r
ed
,
Se
m
i
-
Str
u
ctu
r
ed
a
n
d
Un
s
tr
u
ct
u
r
ed
Data
.
a.
-
Str
u
ctu
r
ed
d
a
ta
i
s
t
h
e
tr
ad
itio
n
al
Data
-
b
ase
t
h
at
co
n
s
i
s
ts
o
f
R
o
w
s
a
n
d
C
o
l
u
m
n
s
an
d
r
es
id
es
in
f
i
x
e
d
f
ield
s
i
n
a
f
i
le.
b.
Un
s
tr
u
ct
u
r
ed
d
ata
d
o
es
n
o
t
h
a
v
e
an
d
d
o
es
n
o
t
ad
h
er
e
to
a
p
r
e
-
d
ef
i
n
ed
s
tr
u
ctu
r
e
l
ik
e
E
-
m
a
ils
,
v
id
eo
an
d
au
d
io
c.
-
Se
m
i
-
Str
u
ct
u
r
ed
Data
d
o
es
n
o
t
co
n
f
ir
m
to
a
s
p
ec
if
ic
ar
r
an
g
e
m
e
n
t
b
u
t
co
n
s
is
t
s
o
f
T
tag
s
to
s
ep
ar
ate
th
e
d
ata
ele
m
e
n
ts
.
2
.
4
.
4.
Ver
a
cit
y
Ver
ac
it
y
i
s
t
h
e
s
p
ec
if
ica
tio
n
th
at
d
e
f
i
n
e
t
h
e
q
u
al
it
y
o
f
d
ata
an
d
t
h
e
le
v
el
o
f
tr
u
s
t
in
v
a
r
io
u
s
d
at
a
s
o
u
r
ce
s
,
i
t
r
ef
er
s
to
d
ata
's
m
e
s
s
i
n
es
s
o
r
tr
u
s
t
w
o
r
th
in
e
s
s
.
W
ith
th
e
h
ig
h
v
elo
cit
y
o
f
b
i
g
d
ata
th
e
q
u
al
it
y
an
d
ac
cu
r
ac
y
ar
e
less
co
n
tr
o
llab
le
,
th
e
m
o
s
t
v
i
s
ib
le
a
n
d
co
n
cr
e
te
ex
a
m
p
le
i
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t
h
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p
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ts
o
n
s
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et
w
o
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k
s
h
as
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tag
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co
llo
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ial
s
p
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h
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n
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ar
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w
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o
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r
ce
s
.
2
.
4
.
5.
Va
lue
T
h
e
last
V
r
ef
er
s
to
th
e
m
o
s
t
i
m
p
o
r
tan
t
ch
ar
ac
ter
i
s
tic
o
f
b
ig
d
ata,
w
h
ic
h
is
t
h
e
v
a
lu
e
t
h
at
ca
n
b
e
ex
tr
ac
ted
f
r
o
m
,
m
an
y
co
m
p
a
n
ies
ar
e
s
tar
ti
n
g
to
g
en
er
ate
ec
o
n
o
m
ic
b
e
n
ef
i
ts
f
r
o
m
th
e
ir
b
ig
d
ata
a
n
d
lo
o
k
f
o
r
b
u
s
i
n
ess
v
al
u
e
cr
ea
tio
n
i
n
ter
m
s
o
f
n
e
w
p
r
o
d
u
cts
o
r
s
er
v
ice
s
.
I
n
th
e
la
s
t
t
w
o
Am
er
ica
n
g
e
n
er
al
elec
tio
n
s
,
th
e
ca
p
ab
ilit
y
o
f
B
ar
ac
k
Ob
a
m
a
‟
s
ca
m
p
aig
n
tea
m
to
ef
f
ec
ti
v
el
y
w
ield
b
ig
d
ata
an
a
l
y
t
ics
w
as
s
ee
n
a
f
ac
to
r
in
h
i
s
v
icto
r
y
o
v
er
h
is
r
iv
a
ls
.
3.
RE
L
AT
E
D
WO
RK
Mo
o
cs
ar
e
a
b
ig
o
p
p
o
r
tu
n
it
y
f
o
r
r
esear
ch
er
s
in
ter
ested
in
lear
n
in
g
m
et
h
o
d
s
,
th
e
p
latf
o
r
m
s
co
n
s
titu
te
a
b
ig
d
ata
s
ets
o
f
s
t
u
d
en
ts
in
t
er
ac
tio
n
s
.
C
o
n
s
id
er
in
g
t
h
e
h
u
g
e
n
u
m
b
er
o
f
p
ar
ticip
a
n
ts
,
la
r
g
e
s
ets
o
f
s
t
u
d
en
t
s
d
ata
ca
n
b
e
an
al
y
ze
d
to
d
ec
ip
h
er
u
s
er
s
o
n
li
n
e
b
eh
a
v
io
r
s
an
d
t
h
eir
co
m
m
it
m
e
n
t p
atter
n
s
(
C
o
f
f
r
in
et
al.
2
0
1
4
)
.
Kizilce
c
et
a
l.
(
2
0
1
3
)
h
av
e
u
s
ed
th
r
ee
Mo
o
cs
o
n
C
o
u
r
s
er
a
p
latf
o
r
m
to
u
s
ed
to
u
n
d
e
r
s
ta
n
d
s
tu
d
e
n
ts
en
g
a
g
e
m
en
t
a
n
d
d
is
e
n
g
a
g
e
m
en
t
b
e
h
av
io
r
s
.
C
o
llected
d
at
a
lik
e
s
t
u
d
en
t
w
atc
h
i
n
g
v
id
eo
co
m
m
it
m
en
t
o
r
s
u
b
m
is
s
io
n
o
f
a
s
s
e
s
s
m
en
t
e
n
ab
led
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e
cla
s
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f
icatio
n
o
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g
a
g
e
m
en
t
i
n
to
f
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u
r
t
y
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l
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eled
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o
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b
eh
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,
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d
itin
g
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an
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at
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ep
r
e
s
en
t
s
u
cc
es
s
iv
el
y
t
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e
"
ass
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g
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m
e
n
t
w
as
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et
o
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ti
m
e"
,
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d
elay
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,
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j
u
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id
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n
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k
te
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ts
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ig
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t"
an
d
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th
e
s
tu
d
e
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ts
th
at
d
id
n
o
t
p
ar
tic
ip
ate
in
t
h
e
co
u
r
s
e
at
all"
.
An
d
er
s
o
n
et
al.
(
2
0
1
4
)
h
av
e
b
ee
n
in
ter
es
ted
b
y
t
h
e
r
elatio
n
b
et
w
ee
n
s
t
u
d
en
t
en
g
a
g
e
m
en
t
/
ac
tiv
it
y
an
d
th
e
f
i
n
ale
g
r
ad
e.
T
h
e
y
n
o
te
t
h
at
th
e
m
ain
ch
ar
ac
ter
i
s
tic
o
f
h
ig
h
ac
h
iev
e
m
e
n
t
is
th
e
f
ac
t
o
f
w
atch
in
g
s
o
m
an
y
v
id
eo
s
o
n
th
e
p
latf
o
r
m
.
S
a
m
e
s
tate
m
en
t
w
a
s
m
e
n
tio
n
ed
b
y
Kar
p
ick
e
an
d
B
lu
n
t
(
2
0
1
1
)
w
h
en
th
e
y
s
h
o
w
ed
th
a
t
th
e
m
o
r
e
t
h
e
lear
n
er
s
w
atc
h
v
i
d
eo
s
th
e
h
i
g
h
e
s
t le
ar
n
in
g
p
er
f
o
r
m
a
n
ce
h
e
ca
n
g
e
t.
San
to
s
e
t
al.
(
2
0
1
4
)
h
av
e
s
h
o
w
ed
t
h
at
t
h
e
s
tu
d
e
n
ts
w
h
o
ar
e
p
ar
ticip
atio
n
m
o
r
e
o
n
co
u
r
s
e
s
ac
ti
v
ities
an
d
ar
e
f
r
eq
u
en
t
l
y
co
m
m
u
n
ic
atin
g
,
d
is
cu
s
s
i
n
g
an
d
co
llab
o
r
atin
g
w
it
h
o
th
er
s
h
av
e
b
ett
er
ch
an
ce
s
p
ass
i
n
g
th
e
co
u
r
s
e.
T
o
m
ax
i
m
ize
p
er
f
o
r
m
a
n
ce
r
ec
o
m
m
e
n
d
in
g
co
u
r
s
es
a
n
d
v
id
eo
s
i
s
v
er
y
i
m
p
o
r
tan
t,
m
o
s
t
o
f
r
ec
o
m
m
e
n
d
er
s
y
s
te
m
s
o
n
Mo
o
c
p
latf
o
r
m
ar
e
b
ased
o
n
tr
ad
i
tio
n
al
r
ec
o
m
m
e
n
d
atio
n
ap
p
r
o
ac
h
es:
co
l
lab
o
r
ativ
e
-
b
ased
,
co
n
ten
t
-
b
ased
o
r
t
h
e
f
u
s
io
n
o
f
t
h
o
s
e
t
w
o
ap
p
r
o
ac
h
es
(
h
y
b
r
id
-
b
ased
f
ilter
i
n
g
)
,
te
ch
n
iq
u
es
h
a
v
e
b
ee
n
s
h
o
w
n
to
b
e
u
s
ef
u
l
in
Mo
o
c
p
latf
o
r
m
.
C
o
llab
o
r
ativ
e
f
ilter
i
n
g
u
s
e
co
m
m
u
n
it
y
d
ata
(
f
ee
d
b
ac
k
,
r
atin
g
s
…
)
to
m
ak
e
r
ec
o
m
m
e
n
d
atio
n
s
.
C
o
n
ten
t
-
b
ased
s
t
u
d
y
ite
m
s
t
h
at
u
s
er
h
a
s
ex
p
r
es
s
ed
h
is
s
a
tis
f
ac
tio
n
o
v
er
it
an
d
p
r
o
p
o
s
e
ite
m
w
it
h
s
i
m
ilar
co
n
ten
t.
T
h
e
m
ai
n
id
ea
is
to
p
r
o
p
o
s
e
eith
er
ite
m
s
th
at
s
at
is
f
ied
s
i
m
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u
s
er
s
o
r
to
p
r
o
p
o
s
e
ite
m
s
s
i
m
ilar
to
t
h
e
o
n
es
th
at
p
leased
t
h
e
u
s
er
.
I
n
s
o
m
e
ca
s
e
s
,
ed
u
ca
tio
n
al
r
ec
o
m
m
en
d
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s
y
s
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m
s
a
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t
s
tu
d
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t
s
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a
s
p
ec
if
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m
e
p
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;
T
h
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p
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ce
o
f
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ti
m
e
p
ar
am
e
ter
af
f
ec
t
s
th
e
r
ec
o
m
m
en
d
atio
n
b
ein
g
r
etr
iev
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.
T
h
er
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r
e,
w
it
h
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u
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f
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m
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wo
r
k
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m
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q
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alit
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t.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
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2
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8
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l.
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2
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1
7
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2
1
5
2
–
2
1
6
0
2156
4.
RE
CO
M
M
E
NDER SY
ST
E
M
First
w
eb
m
aster
s
p
r
o
b
lem
is
to
attr
ac
t
u
s
er
s
to
t
h
eir
w
eb
s
i
tes
b
y
p
r
ese
n
ti
n
g
p
leasan
t
co
n
ten
t
an
d
cr
ea
tin
g
a
b
r
an
d
i
m
a
g
e
f
o
r
th
e
i
r
w
eb
s
ite
s
o
it
ca
n
b
e
v
is
ib
le
o
n
th
e
w
eb
,
th
e
s
ec
o
n
d
p
r
o
b
le
m
is
to
k
ee
p
u
s
er
s
h
o
o
k
ed
u
p
o
n
th
e
w
eb
s
ite
a
n
d
attac
h
i
n
g
t
h
e
m
b
y
o
f
f
er
i
n
g
c
o
n
ten
t
th
at
p
leases
t
h
e
u
s
er
a
n
d
th
e
m
o
s
t
clo
s
e
t
o
th
eir
p
r
ef
er
en
ce
s
.
L
i
k
e
Yo
u
T
u
b
e
o
r
Am
az
o
n
m
a
n
y
o
t
h
er
w
eb
s
ite
s
u
s
e
s
r
e
co
m
m
en
d
er
s
y
s
te
m
s
o
th
e
y
ca
n
k
e
ep
s
u
r
f
er
s
h
o
o
k
ed
o
n
th
e
w
eb
s
ite,
s
o
th
ey
ca
n
m
a
x
i
m
ize
th
eir
b
en
e
f
it,
b
y
s
u
g
g
e
s
tio
n
ite
m
th
a
t
m
a
y
p
lease
to
clien
t
f
o
r
th
e
ca
s
e
o
f
e
-
co
m
m
er
ce
co
m
p
an
y
a
s
Am
az
o
n
o
r
E
B
ay
.
Ma
n
y
Me
th
o
d
s
ar
e
u
s
ed
to
r
ec
o
m
m
e
n
d
co
n
te
n
t,
t
h
e
m
o
s
t
p
o
p
u
lar
ar
e
co
n
ten
t
b
ased
m
e
th
o
d
s
th
a
t
f
o
cu
s
o
n
th
e
co
n
te
n
t
(
ite
m
's
d
escr
ip
tio
n
f
o
r
co
m
m
er
cial
ar
ti
cle,
v
id
eo
m
etad
ata
…
)
an
d
c
o
llab
o
r
ativ
e
f
ilter
in
g
m
et
h
o
d
s
th
at
f
o
cu
s
o
n
th
e
o
t
h
e
r
u
s
er
s
f
ee
d
b
ac
k
a
n
d
in
ter
ac
tio
n
.
R
ec
o
m
m
e
n
d
er
s
y
s
te
m
ar
e
also
a
s
o
lu
tio
n
to
f
ac
ilit
ate
r
esear
c
h
an
d
ec
o
n
o
m
ize
ti
m
e
co
n
s
u
m
ed
to
f
in
d
in
f
o
r
m
atio
n
i
n
a
w
eb
,
g
r
o
w
i
n
g
e
x
p
o
n
en
tiall
y
,
to
p
er
m
it
p
er
s
o
n
alizi
n
g
w
eb
s
i
te
ac
co
r
d
in
g
to
u
s
er
s
i
n
ter
est
s
o
th
e
y
w
ill b
e
ab
le
to
g
et
in
f
o
r
m
atio
n
n
e
ed
ed
w
ith
m
i
n
i
m
u
m
e
f
f
o
r
t.
4
.
1
.
Co
nte
nt
-
ba
s
ed
F
ilte
ring
A
l
s
o
r
ef
er
r
ed
to
as
co
g
n
itiv
e
f
ilter
i
n
g
,
p
r
o
p
o
s
e
ite
m
s
b
ased
o
n
co
r
r
elatio
n
b
etw
ee
n
u
s
er
p
ast
ite
m
ch
o
ices
a
n
d
t
h
e
co
n
ten
t
o
f
ea
c
h
ite
m
,
s
o
it
r
ec
o
m
m
e
n
d
ite
m
s
,
s
i
m
ilar
to
t
h
o
s
e
p
r
ev
io
u
s
l
y
s
elec
ted
,
th
at
m
atc
h
p
r
o
b
a
b
ly
t
h
e
m
o
s
t to
u
s
er
p
r
ef
er
en
ce
s
.
C
o
n
te
n
t
b
ased
f
ilter
i
n
g
ar
e
b
ased
o
n
cr
ea
tin
g
co
n
n
ec
tio
n
s
b
et
w
ee
n
ite
m
s
i
n
a
co
llectio
n
,
s
o
w
h
e
n
u
s
er
m
a
n
i
f
est
p
r
ef
er
en
ce
f
o
r
a
s
p
ec
if
ic
o
b
j
ec
t,
s
y
s
te
m
tr
ac
e
th
e
ite
m
co
n
n
ec
t
io
n
s
,
r
ec
o
m
m
en
d
ite
m
s
w
it
h
m
ax
i
m
u
m
d
eg
r
ee
o
f
s
e
m
b
lan
c
e
[
1
7
]
.
P
u
r
e
co
n
ten
t
-
b
ased
r
ec
o
m
m
e
n
d
atio
n
s
d
o
n
o
t
tak
e
in
co
n
s
id
er
atio
n
o
th
e
r
u
s
er
s
p
r
ef
er
e
n
ce
s
(
S
c
h
ei
n
,
P
o
p
escu
l,
&
U
n
g
ar
,
2
0
0
2
)
.
4
.
2
.
Co
lla
bo
ra
t
iv
e
F
ilte
ring
I
s
th
e
p
r
o
ce
s
s
o
f
co
llecti
n
g
u
s
er
f
ee
d
b
ac
k
o
n
a
co
n
ten
t
(
r
atin
g
,
li
k
e/d
is
li
k
e
.
.
.
)
an
d
b
y
c
o
m
p
ar
i
n
g
s
i
m
ilar
ities
a
n
d
d
if
f
er
en
ce
s
a
m
o
n
g
s
e
v
er
al
u
s
er
s
p
r
o
f
iles
,
we
w
il
l
b
e
ab
le
to
d
eter
m
i
n
ate
h
o
w
to
r
ec
o
m
m
en
d
a
co
n
ten
t.
C
o
llab
o
r
ativ
e
f
ilter
i
n
g
is
t
h
e
m
o
s
t
co
m
m
o
n
l
y
u
s
ed
m
et
h
o
d
in
m
a
k
i
n
g
r
ec
o
m
m
en
d
atio
n
s
y
s
te
m
.
T
h
e
b
asic
id
ea
is
id
en
t
if
y
i
n
g
g
r
o
u
p
o
f
u
s
er
s
w
it
h
s
i
m
ilar
p
r
ef
e
r
en
ce
s
a
n
d
r
ec
o
m
m
e
n
d
in
g
f
a
v
o
r
ite
ite
m
s
o
f
th
e
g
r
o
u
p
to
ea
ch
u
s
er
.
I
n
o
th
er
wo
r
d
s
,
th
e
ev
alu
a
tio
n
g
i
v
en
b
y
u
s
er
to
r
esp
ec
tiv
e
i
te
m
s
b
ased
o
n
th
e
s
ta
tis
t
ics
o
f
v
alu
e,
ar
e
u
s
ed
to
id
en
ti
f
y
t
h
e
u
s
er
g
r
o
u
p
w
i
th
clo
s
er
p
r
ef
er
en
ce
,
it
is
th
o
s
e
th
at
r
ec
o
m
m
en
d
ite
m
s
to
o
th
er
u
s
er
s
o
f
t
h
e
g
r
o
u
p
.
th
e
ev
al
u
at
io
n
v
al
u
es
ar
e
m
an
i
f
e
s
ted
ex
p
licitl
y
a
n
d
i
m
p
licitl
y
.
E
x
p
licit
m
an
if
e
s
tatio
n
s
ar
e
th
o
s
e
o
b
t
ain
ed
b
y
ex
p
licitl
y
ex
p
r
ess
i
n
g
t
h
e
ev
al
u
atio
n
o
f
th
e
ite
m
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y
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er
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k
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o
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tto
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atin
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.
.
.
)
.
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m
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a
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s
tatio
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i
s
to
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h
o
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p
r
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n
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d
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ter
e
s
t b
y
tak
e
n
ac
tio
n
o
n
t
h
e
ite
m
(
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o
w
n
lo
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in
g
,
s
h
ar
in
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,
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s
iti
n
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,
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o
m
m
e
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d
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to
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f
r
ie
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d
,
p
u
r
ch
asi
n
g
.
.
.
).
4
.
3
.
H
y
brid f
ilte
ring
I
s
th
e
h
y
b
r
i
d
ap
p
r
o
ac
h
t
h
at
c
o
m
b
i
n
e
co
llab
o
r
ativ
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to
co
n
te
n
t
-
b
ased
f
i
lter
in
g
,
t
h
is
ap
p
r
o
a
ch
ca
n
b
e
i
m
p
le
m
en
ted
i
n
s
e
v
er
al
w
a
y
s
:
a.
C
o
m
b
i
n
in
g
r
es
u
lt o
f
co
n
ten
t b
ased
an
d
co
llab
o
r
ativ
e
b
ased
f
ilter
in
g
ex
ec
u
ted
s
ep
ar
atel
y
.
b.
Giv
i
n
g
co
n
ten
t
-
b
ased
m
et
h
o
d
th
e
ca
p
ab
ilit
ies o
f
t
h
e
co
llab
o
r
ativ
e
-
b
ased
o
n
e
o
r
th
e
in
v
er
s
e.
c.
Un
i
f
y
in
g
i
n
to
o
n
e
m
o
d
el
th
e
t
w
o
ap
p
r
o
ac
h
es.
Stu
d
ies
t
h
at
co
m
p
ar
ed
th
e
r
es
u
lts
o
f
th
e
h
y
b
r
id
m
et
h
o
d
to
th
e
co
llab
o
r
ativ
e
an
d
th
e
co
n
t
en
t
b
ased
m
et
h
o
d
s
h
av
e
co
n
f
ir
m
ed
th
e
lead
o
f
h
y
b
r
id
ap
p
r
o
ac
h
to
th
e
t
w
o
o
th
er
p
u
r
e
ap
p
r
o
ac
h
es
v
is
-
a
-
v
i
s
th
e
ac
cu
r
ac
y
o
f
r
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s
.
t
h
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eth
o
d
is
al
s
o
a
s
o
lu
tio
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to
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h
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at
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o
f
co
ld
s
tar
t a
n
d
s
p
ar
s
it
y
p
r
o
b
lem
.
5.
P
RO
P
O
SE
D
T
E
M
P
L
AT
E
As
w
e
k
n
o
w
f
ee
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g
s
h
as
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ig
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ce
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n
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n
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iv
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ig
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ld
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p
t
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o
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,
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d
d
o
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t
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m
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ev
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if
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ased
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I
n
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n
s
id
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ith
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u
r
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.
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Data
J
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e
p
r
o
f
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io
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al
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ti
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it
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5
.
1
.
G
en
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T
h
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v
ar
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le
th
at
ca
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av
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t
wo
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e
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e
r
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e
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t
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elate
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ess
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ce
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ield
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ilar
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r
r
elatio
n
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asp
ec
ts
[
1
8
]
.
5
.
2
.
Aca
de
m
ic
L
ev
el
Nex
t
to
g
en
d
er
,
ac
a
d
e
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ic
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a
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t f
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h
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e
3
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w
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1
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,
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ed
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m
(
1
)
,
h
ig
h
(
1
)
.
5
.
3
.
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t
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o
f
M
in
A
ll
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an
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ch
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ices
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li
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e
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e
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ce
d
b
y
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ee
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n
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an
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th
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tate
o
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m
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d
.
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ith
i
n
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s
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ch
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lar
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e
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u
m
b
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tu
d
ie
s
h
a
v
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s
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er
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i
m
p
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t
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ed
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s
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n
ti
m
en
t
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n
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[1
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Bo
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p
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Jo
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4
[5
]
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Web
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]
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1
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[7
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ter
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trica
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mp
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ter
En
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3
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0
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4
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p
p
.
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4
7
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[8
]
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Ro
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Em
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a
,
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A
d
o
p
ti
o
n
o
f
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rn
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b
y
lea
rn
e
rs:
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n
e
m
p
ir
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stu
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y
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ti
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2
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6
.
[9
]
W
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,
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.
,
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.
,
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o
,
J.,
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,
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.
J.
H.
“
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P
e
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o
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n
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e
-
Orie
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ted
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p
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rn
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lac
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u
c
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ti
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a
l
T
e
c
h
n
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y
&
S
o
c
iet
y
,
1
3
(4
),
1
6
7
–
1
7
9
.
[1
0
]
M
a
y
e
r,
R.
,
Clark
,
R.
“
E
-
L
e
a
rn
in
g
a
n
d
t
h
e
S
c
ien
c
e
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f
In
str
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ti
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n
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ro
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,
3
rd
e
d
n
”,
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o
k
2
0
1
2
.
[1
1
]
R.
G
a
rriso
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-
L
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rn
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2
1
st Cen
tu
ry
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F
ra
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w
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Re
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rc
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n
d
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k
2
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1
1
.
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2
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Kiz
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e
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R.
F
.
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.
,
&
S
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n
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c
ti
n
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ise
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g
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g
e
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e
n
t:
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n
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y
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L
e
a
rn
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'
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3
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tern
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e
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n
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ly
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d
Kn
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e
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7
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7
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.
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3
]
S
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Evaluation Warning : The document was created with Spire.PDF for Python.