I
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Adv
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Appl
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s
(
I
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1
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6
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.
1
9
~
28
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SS
N:
2252
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8
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DOI
:
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.
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sio
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s
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ti
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p
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f
o
r
ra
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tru
si
o
n
a
c
c
id
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ts i
n
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g
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ey
w
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r
d
s
:
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cc
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t a
n
aly
s
is
F
au
lt tr
ee
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s
is
Nig
er
ian
r
ail
n
etwo
r
k
R
ailway
ac
cid
en
ts
R
is
k
tr
ee
R
o
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t c
au
s
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aly
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is
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s
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p
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n
a
c
c
e
ss
a
rticle
u
n
d
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r th
e
CC B
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SA
li
c
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se
.
C
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r
r
e
s
p
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ing
A
uth
o
r
:
Mo
h
d
Kh
air
u
l A
f
za
n
Mo
h
d
L
az
i
Facu
lty
o
f
C
iv
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n
g
in
ee
r
in
g
,
Un
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s
iti T
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o
lo
g
i M
ala
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s
ia
J
o
h
o
r
B
ah
r
u
8
1
3
1
0
,
Ma
la
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s
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E
m
ail:
m
o
h
d
k
h
air
u
laf
za
n
@
u
tm
.
m
y
1.
I
NT
RO
D
UCT
I
O
N
R
ailway
tr
an
s
p
o
r
tatio
n
h
as
l
o
n
g
b
ee
n
a
n
ess
en
tial
co
m
p
o
n
en
t
o
f
Nig
er
ia'
s
ec
o
n
o
m
ic
an
d
s
o
cia
l
f
ab
r
ic,
d
atin
g
b
ac
k
t
o
th
e
co
l
o
n
ial
er
a
w
h
en
t
h
e
B
r
itis
h
co
l
o
n
ial
ad
m
in
is
tr
atio
n
in
itiated
th
e
co
n
s
tr
u
ctio
n
o
f
r
ailway
lin
es
to
f
ac
ilit
ate
th
e
ex
tr
ac
tio
n
an
d
ex
p
o
r
tatio
n
o
f
n
atu
r
al
r
eso
u
r
ce
s
[1
]
,
[
2]
.
Ov
er
th
e
last
d
ec
ad
e,
Nig
er
ia'
s
r
ailway
n
etwo
r
k
h
as
u
n
d
er
g
o
n
e
v
ar
io
u
s
p
h
ases
o
f
ex
p
an
s
io
n
an
d
m
o
d
er
n
izatio
n
,
r
ef
lectin
g
s
h
if
ts
i
n
g
o
v
er
n
m
en
t
p
r
io
r
ities
a
n
d
te
ch
n
o
lo
g
ical
ad
v
a
n
ce
m
en
ts
[
3
]
.
T
h
e
Nig
er
ian
R
ailway
C
o
r
p
o
r
ati
o
n
(
NR
C
)
,
estab
lis
h
ed
in
1
9
5
5
,
h
as
b
e
en
en
tr
u
s
ted
with
m
a
n
ag
in
g
an
d
o
p
er
atin
g
th
e
co
u
n
tr
y
'
s
r
ailway
s
y
s
tem
,
o
v
er
s
ee
in
g
a
n
etwo
r
k
o
f
lin
es
co
n
n
ec
tin
g
m
ajo
r
cities,
p
o
r
ts
,
an
d
in
d
u
s
tr
ial
h
u
b
s
[
4
]
.
Desp
ite
its
h
is
to
r
ical
s
ig
n
if
ica
n
ce
an
d
p
o
ten
tial
f
o
r
ec
o
n
o
m
ic
g
r
o
wth
,
Nig
e
r
ia'
s
r
ailway
s
ec
to
r
h
as
f
ac
ed
p
er
s
is
ten
t
ch
allen
g
es,
in
clu
d
in
g
in
a
d
eq
u
ate
f
u
n
d
in
g
,
o
u
td
ated
in
f
r
astru
ctu
r
e,
o
p
er
ati
o
n
al
in
ef
f
icien
cies,
Evaluation Warning : The document was created with Spire.PDF for Python.
I
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N
:
2
2
5
2
-
8
8
1
4
I
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t J Ad
v
Ap
p
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,
Vo
l.
1
5
,
No
.
1
,
Ma
r
c
h
2
0
2
6
:
19
-
28
20
an
d
s
af
ety
co
n
ce
r
n
s
[
5
]
.
T
h
e
s
af
ety
o
f
r
ailway
o
p
er
atio
n
s
h
as e
m
er
g
ed
as a
p
r
ess
in
g
i
s
s
u
e,
p
ar
ticu
lar
ly
in
lig
h
t
o
f
th
e
i
n
cr
ea
s
in
g
f
r
eq
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cy
o
f
s
af
ety
in
cid
en
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an
d
ac
cid
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n
t
s
r
ec
o
r
d
ed
ac
r
o
s
s
th
e
n
etwo
r
k
in
r
ec
en
t
y
ea
r
s
[
6
]
.
Ag
ain
s
t
th
is
b
ac
k
d
r
o
p
,
th
is
p
a
p
er
em
b
ar
k
s
o
n
a
co
m
p
r
e
h
en
s
iv
e
an
aly
s
is
o
f
r
ailway
ac
cid
en
ts
in
Nig
er
ia
o
v
er
th
e
last
d
ec
ad
e.
T
h
is
tim
ef
r
a
m
e
en
co
m
p
ass
es
a
p
er
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d
o
f
s
ig
n
if
ican
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ch
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g
e
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d
d
ev
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m
en
t
with
in
th
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Nig
er
ian
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ailway
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r
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ar
k
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y
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g
o
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m
en
t
in
itiativ
es,
in
f
r
astru
ctu
r
e
u
p
g
r
ad
es,
an
d
ef
f
o
r
ts
to
r
ev
italize
th
e
co
u
n
tr
y
'
s
r
ail
n
etwo
r
k
.
Saf
ety
in
r
ailway
s
r
ef
e
r
s
to
th
e
m
ea
s
u
r
es
an
d
p
r
o
to
c
o
ls
im
p
lem
en
ted
t
o
p
r
o
tect
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en
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er
s
,
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p
lo
y
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s
,
an
d
in
f
r
astru
ctu
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e
f
r
o
m
ac
cid
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ts
,
in
cid
en
ts
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an
d
o
th
e
r
h
az
ar
d
s
[
7
]
.
A
r
ailway
s
y
s
tem
'
s
s
af
ety
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u
ld
b
e
m
ea
s
u
r
ed
u
s
in
g
eith
er
a
r
is
k
-
lev
el
a
p
p
r
o
ac
h
o
r
an
in
cid
e
n
t in
d
icat
o
r
[
8
]
.
T
h
e
r
is
k
lev
el
a
p
p
r
o
ac
h
,
a
q
u
alitativ
e
ap
p
r
o
ac
h
,
o
f
f
e
r
s
a
d
e
f
in
ed
class
if
icatio
n
o
f
r
is
k
s
b
a
s
ed
o
n
th
e
f
r
eq
u
e
n
cy
a
n
d
s
ev
er
ity
o
f
ev
en
ts
[9
]
–
[
11]
.
T
h
ese
q
u
alitativ
e
id
en
tifie
r
s
c
o
u
ld
b
e
tr
a
n
s
lated
to
n
u
m
er
ical
v
alu
es
to
q
u
a
n
tify
t
h
e
s
af
ety
p
er
f
o
r
m
an
ce
o
f
a
r
ailway
c
o
m
p
o
n
en
t,
s
u
b
-
s
y
s
tem
,
o
r
s
y
s
tem
[
1
2
]
.
On
t
h
e
o
th
er
h
an
d
,
th
e
in
cid
e
n
t
in
d
icato
r
ap
p
r
o
ac
h
is
a
p
u
r
ely
q
u
an
tit
ativ
e
ass
es
s
m
en
t
o
f
s
af
ety
th
at
m
ea
s
u
r
es
s
af
ety
in
cid
en
ts
o
v
er
tim
e
[
1
3
]
–
[
16]
.
T
y
p
ical
in
cid
en
t
in
d
icato
r
s
s
et
o
u
t
b
y
th
e
E
u
r
o
p
ea
n
Un
io
n
Ag
en
cy
f
o
r
R
ailway
s
(
E
R
A)
in
clu
d
e
th
e
to
tal
n
u
m
b
e
r
o
f
s
er
io
u
s
ac
cid
en
ts
,
d
is
tr
ib
u
tio
n
o
f
ac
ci
d
en
ts
p
er
ac
cid
e
n
t
ca
teg
o
r
y
,
a
n
d
f
atality
r
is
k
in
d
i
ca
to
r
[
1
7
]
.
T
h
e
s
ig
n
if
ican
ce
o
f
th
is
r
esear
ch
lies
in
its
p
o
ten
tial
to
p
r
o
v
i
d
e
v
alu
ab
le
i
n
s
ig
h
ts
in
to
th
e
u
n
d
er
ly
in
g
f
ac
to
r
s
co
n
tr
ib
u
tin
g
to
r
ailwa
y
ac
cid
en
ts
in
Nig
er
ia,
o
f
f
er
i
n
g
a
h
is
to
r
ical
p
er
s
p
ec
tiv
e
o
n
th
e
ev
o
lu
ti
o
n
o
f
s
af
ety
ch
allen
g
es
with
in
th
e
co
n
tex
t
o
f
b
r
o
a
d
er
d
ev
elo
p
m
en
ts
in
th
e
r
ailway
s
ec
to
r
.
T
h
is
s
tu
d
y
aim
s
t
o
id
en
tify
tr
e
n
d
s
,
p
atter
n
s
,
a
n
d
r
o
o
t
ca
u
s
es
b
y
ex
am
in
in
g
a
d
ec
ad
e'
s
in
cid
en
t
d
ata,
in
f
o
r
m
i
n
g
e
v
id
en
ce
-
b
ased
s
tr
ateg
ies
f
o
r
e
n
h
an
ci
n
g
r
ailway
s
af
ety
s
tan
d
ar
d
s
a
n
d
m
itig
atin
g
r
is
k
s
.
T
h
e
r
est
o
f
th
e
p
a
p
er
is
s
tr
u
ctu
r
ed
as
f
o
llo
ws.
T
h
e
s
ec
tio
n
d
escr
ib
es
th
e
r
esear
ch
d
ata
an
d
m
eth
o
d
o
lo
g
y
a
d
o
p
te
d
in
th
is
s
tu
d
y
.
Sectio
n
3
p
r
esen
ts
th
e
r
esu
lts
o
f
th
e
a
n
aly
s
is
an
d
d
is
cu
s
s
es
th
e
f
in
d
in
g
s
to
d
e
r
iv
e
in
s
ig
h
ts
.
Sectio
n
4
p
r
o
v
i
d
es
co
n
clu
s
io
n
s
o
n
th
e
r
esu
lts
d
is
cu
s
s
ed
,
an
d
s
ec
tio
n
5
en
d
s
th
e
p
ap
er
with
s
o
m
e
av
en
u
es f
o
r
f
u
tu
r
e
r
esear
ch
.
2.
RE
S
E
ARCH
DA
T
A
AND
M
E
T
H
O
D
2
.
1
.
Da
t
a
c
o
llect
io
n
Data
o
n
r
ailway
s
af
ety
in
cid
en
ts
in
Nig
er
ia
wer
e
co
llected
f
r
o
m
two
s
o
u
r
ce
s
.
A
s
tatis
tica
l
s
u
m
m
ar
y
o
f
r
ailway
ac
cid
en
ts
was
o
b
tai
n
ed
f
r
o
m
NR
C
’
s
an
n
u
al
r
ep
o
r
ts
an
d
o
f
f
icial
b
u
lletin
s
.
Do
c
u
m
en
ted
ac
c
o
u
n
ts
o
f
r
ailway
ac
cid
en
ts
wer
e
ex
tr
ac
ted
f
r
o
m
n
ews
r
ep
o
r
ts
to
id
en
t
if
y
lik
ely
ca
u
s
al
f
ac
to
r
s
an
d
e
s
tab
lis
h
a
r
is
k
tr
ee
.
T
h
e
Un
ited
States
o
f
Am
er
ica
(
USA)
an
d
Un
ited
Kin
g
d
o
m
(
UK)
wer
e
ch
o
s
en
f
o
r
c
o
m
p
ar
ativ
e
an
aly
s
is
an
d
b
en
ch
m
ar
k
in
g
.
Stan
d
a
r
d
m
etr
i
cs
u
s
ed
to
co
m
p
ar
e
th
e
s
af
ety
p
er
f
o
r
m
a
n
ce
o
f
r
ail
n
etwo
r
k
s
b
ased
o
n
in
cid
e
n
t
in
d
icato
r
s
ar
e
an
n
u
al
r
ailway
in
ju
r
ies
an
d
f
atalities
p
er
m
ill
io
n
tr
ain
k
ilo
m
eter
s
[
1
8
]
,
[
1
9
]
.
C
o
m
p
ar
ativ
e
d
ata
(
an
n
u
al
tr
ai
n
k
ilo
m
eter
s
tr
a
v
e
lled
,
an
n
u
al
r
ailway
in
ju
r
ies
,
an
d
f
atalities
r
ec
o
r
d
e
d
)
wer
e
o
b
tain
ed
f
r
o
m
t
h
e
Fed
er
al
R
ailr
o
ad
Ad
m
in
is
tr
atio
n
(
FR
A)
an
d
Of
f
ice
o
f
R
ail
an
d
R
o
ad
(
OR
R
)
d
atab
ases
f
o
r
th
e
US
A
an
d
UK
r
ail
n
etwo
r
k
s
,
r
esp
ec
tiv
ely
(
Fig
u
r
e
1
)
.
Fig
u
r
e
1
.
R
esear
ch
d
ata
a
n
d
m
eth
o
d
o
lo
g
y
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J Ad
v
Ap
p
l Sci
I
SS
N:
2252
-
8
8
1
4
A
n
a
lysi
s
o
f ra
ilw
a
y
a
cc
id
en
ts
in
N
ig
eria
:
a
d
ec
a
d
e
o
f in
s
ig
h
ts
(
A
liyu
Ma
n
i U
ma
r
)
21
Data
o
n
tr
ain
k
ilo
m
etr
es tr
av
elled
with
in
Nig
er
ia’
s
r
ailway
n
etwo
r
k
is
n
o
t r
ea
d
ily
av
ailab
le.
As s
u
ch
,
we
d
ev
is
ed
a
way
o
f
o
b
tain
in
g
an
esti
m
ate
o
f
th
e
d
ata.
T
r
ain
k
ilo
m
etr
es a
r
e
o
b
tain
ed
f
r
o
m
b
o
th
p
ass
en
g
er
an
d
f
r
eig
h
t
tr
ain
s
.
W
h
en
o
p
e
r
atio
n
al,
p
ass
en
g
er
tr
ain
s
o
n
t
h
e
Nig
er
ian
r
ailway
n
etwo
r
k
o
p
er
ate
o
n
a
f
ix
ed
tim
etab
le.
Hen
ce
,
tr
ain
tim
etab
les
f
o
r
th
e
tr
ain
r
o
u
tes
with
in
th
e
Nig
er
ian
r
ail
n
etwo
r
k
wer
e
o
b
tain
ed
f
o
r
p
ass
en
g
er
tr
ain
s
.
T
h
e
tim
etab
le
p
r
o
v
id
es
in
f
o
r
m
atio
n
o
n
n
u
m
b
er
o
f
wee
k
ly
tr
ain
tr
ip
s
alo
n
g
ea
c
h
r
o
u
te
.
Hen
ce
,
an
n
u
al
tr
ain
k
ilo
m
etr
e
s
co
u
ld
b
e
ca
lcu
lated
b
y
m
u
ltip
ly
in
g
th
e
n
u
m
b
er
o
f
tr
i
p
s
ea
c
h
tr
ain
m
a
k
es
in
th
e
y
ea
r
b
y
th
e
r
o
u
te
d
is
tan
ce
.
T
h
e
p
er
io
d
s
in
wh
ich
tr
ain
o
p
e
r
atio
n
s
ar
e
s
u
s
p
en
d
ed
alo
n
g
a
r
o
u
te
ar
e
d
ed
u
cted
f
r
o
m
th
e
an
n
u
al
to
tal.
C
o
n
s
id
er
atio
n
was
g
iv
en
to
th
e
p
er
io
d
wh
en
n
ew
lin
es
s
tar
ted
o
p
er
atin
g
to
ac
co
u
n
t
f
o
r
th
eir
ac
tu
al
co
n
tr
i
b
u
tio
n
t
o
th
e
to
tal
an
n
u
al
tr
ai
n
k
ilo
m
etr
es t
r
av
elled
.
T
h
e
ch
allen
g
e
lies
in
estab
lis
h
in
g
th
e
an
n
u
al
tr
ain
k
ilo
m
etr
e
s
tr
av
elled
b
y
f
r
ei
g
h
t
tr
ain
s
s
i
n
ce
f
r
eig
h
t
tr
ain
s
d
o
n
o
t
f
o
llo
w
f
ix
ed
tim
etab
les.
Fo
r
tu
n
ately
,
th
e
Nig
e
r
ian
B
u
r
ea
u
o
f
Statis
tics
(
NB
S)
p
u
b
lis
h
es
an
n
u
al
r
ep
o
r
ts
o
n
r
ev
en
u
e
g
e
n
er
ated
f
r
o
m
r
ail
f
r
ei
g
h
t
tr
a
n
s
p
o
r
tatio
n
,
with
t
h
e
r
o
u
tes
r
esp
o
n
s
ib
le
f
o
r
s
u
ch
r
ev
e
n
u
e.
NR
C
an
n
u
al
r
ep
o
r
ts
also
co
n
tain
in
f
o
r
m
atio
n
th
at
co
u
ld
allo
w
f
o
r
d
ata
wr
an
g
lin
g
to
o
b
tain
esti
m
ates
o
f
an
n
u
al
f
r
eig
h
t tr
ain
k
ilo
m
etr
es
tr
av
elled
.
2
.
2
.
Da
t
a
a
na
ly
s
is
Fo
u
r
ty
p
es
o
f
ass
ess
m
en
ts
wer
e
co
n
d
u
cte
d
o
n
th
e
c
o
lle
cted
r
ailway
s
af
ety
in
cid
en
t
d
ata.
First,
Nig
er
ian
r
ailway
s
af
ety
in
cid
e
n
t
d
ata
w
er
e
s
u
b
jecte
d
to
d
esc
r
ip
tiv
e
s
tatis
tical
an
aly
s
i
s
to
id
en
tify
tr
en
d
s
in
th
e
f
r
eq
u
e
n
cy
,
s
ev
er
ity
,
an
d
d
is
tr
ib
u
tio
n
o
f
r
ailway
s
af
ety
in
cid
en
ts
o
v
er
t
h
e
s
tu
d
y
p
er
io
d
.
Nex
t,
th
e
s
tu
d
y
co
n
d
u
cts
a
co
m
p
ar
ativ
e
an
aly
s
is
o
f
r
ailway
s
af
ety
in
cid
en
ts
in
Nig
er
ia
with
two
ad
v
an
ce
d
r
ailway
s
y
s
tem
s
.
Acc
id
en
t
s
ev
er
ity
ex
p
r
ess
ed
in
in
ju
r
ies
an
d
f
atalities
p
er
m
illi
o
n
tr
ain
k
ilo
m
eter
s
tr
av
elled
was
u
s
ed
as
a
u
n
it
o
f
c
o
m
p
ar
is
o
n
.
T
h
e
th
i
r
d
ass
e
s
s
m
en
t
was
co
n
d
u
cte
d
u
s
in
g
a
f
au
lt
tr
ee
a
n
aly
s
is
to
estab
li
s
h
a
to
p
–
d
o
wn
r
is
k
tr
ee
th
at
d
ep
icts
th
e
ca
u
s
ality
ch
ain
o
f
r
ailway
ac
cid
en
ts
in
Nig
e
r
ia.
T
h
is
r
is
k
tr
ee
s
er
v
es
as
a
b
asis
f
o
r
r
o
o
t
-
ca
u
s
e
an
aly
s
is
o
f
Nig
er
ia'
s
m
o
s
t
d
o
m
in
an
t
r
ail
ac
cid
en
t
ty
p
e
(
r
ailway
in
tr
u
s
io
n
ac
cid
en
t)
.
B
ased
o
n
th
e
r
o
o
t
ca
u
s
e
an
aly
s
is
,
a
co
m
p
ar
ativ
e
f
r
am
ewo
r
k
is
u
s
ed
to
ass
ess
th
e
ef
f
ec
tiv
en
ess
o
f
ex
is
ti
n
g
s
af
ety
m
ea
s
u
r
es,
id
en
tify
g
a
p
s
,
an
d
b
en
ch
m
ar
k
Nig
er
ia'
s
r
ailway
s
af
ety
p
er
f
o
r
m
an
ce
ag
ain
s
t g
lo
b
al
s
tan
d
ar
d
s
.
3.
RE
SU
L
T
S AN
D
D
I
SCU
SS
I
O
N
3
.
1
.
T
em
po
r
a
l dis
t
ributio
n o
f
ra
ilwa
y
a
cc
idents in Nig
er
ia
Prio
r
to
2
0
2
2
,
t
h
e
NR
C
an
d
Nig
er
ia
Po
lice
Fo
r
ce
(
NPF)
e
x
clu
s
iv
ely
h
a
d
t
h
e
co
n
s
titu
tio
n
al
m
an
d
ate
to
co
n
d
u
ct
in
v
esti
g
atio
n
s
r
el
ated
to
r
ailway
ac
cid
en
ts
.
W
ith
th
e
r
ep
ea
l
o
f
th
e
Acc
id
en
t
I
n
v
esti
g
atio
n
B
u
r
ea
u
–
Nig
er
ia
(
AI
B
-
N)
Act
2
0
0
6
a
n
d
its
r
ep
lace
m
en
t w
ith
th
e
Nig
er
ian
Saf
ety
I
n
v
esti
g
at
io
n
B
u
r
ea
u
(
NSI
B
)
Act
2
0
2
2
,
th
e
m
an
d
ate
o
f
co
n
d
u
ctin
g
a
co
m
p
r
e
h
en
s
iv
e
r
ailway
ac
cid
en
t
in
v
esti
g
atio
n
n
o
w
lies
wi
th
th
e
NSI
B
.
So
f
ar
,
th
e
NSI
B
h
a
s
s
et
o
u
t
o
n
its
m
aid
en
r
ailw
ay
ac
cid
en
t
in
v
esti
g
atio
n
with
th
e
Pu
b
lic
W
o
r
k
s
Dep
ar
tm
en
t
(
PW
D
)
lev
el
cr
o
s
s
in
g
(
L
C
)
ac
cid
en
t in
L
a
g
o
s
,
wh
ich
o
cc
u
r
r
ed
o
n
9
th
Ma
r
ch
2
0
2
3
.
Pre
lim
in
ar
y
ac
cid
e
n
t
r
ep
o
r
ts
u
s
u
ally
co
m
e
f
r
o
m
th
e
NR
C
th
r
o
u
g
h
p
r
ess
r
elea
s
es
o
r
th
e
co
r
p
o
r
atio
n
'
s
o
f
f
icial
web
s
ite.
Ho
wev
er
,
in
m
o
s
t
ca
s
es,
s
u
ch
r
ep
o
r
ts
f
ail
to
ascer
tain
th
e
s
ev
er
ity
o
f
r
ailway
ac
cid
en
ts
,
p
ar
ticu
lar
ly
th
e
n
u
m
b
er
o
f
in
j
u
r
ed
v
ictim
s
an
d
th
e
s
ev
er
ity
o
f
s
u
ch
in
ju
r
ies.
T
h
is
is
attr
ib
u
ted
to
th
e
f
ac
t
th
at
ac
cid
en
t
v
ictim
s
wh
o
s
u
s
tain
in
ju
r
ies
s
eld
o
m
wait
f
o
r
r
esp
o
n
s
e
(
o
r
in
v
esti
g
atio
n
)
team
s
to
ar
r
iv
e
b
ef
o
r
e
d
is
ch
ar
g
in
g
th
em
s
elv
es,
ex
ce
p
t
in
ca
s
es
wh
er
e
th
e
s
ev
er
ity
o
f
in
ju
r
y
is
well
p
r
o
n
o
u
n
c
ed
.
As
s
u
ch
,
wh
en
u
n
av
ailab
le,
s
u
ch
d
ata
was e
s
tim
ated
u
s
in
g
s
im
ilar
ac
cid
en
ts
with
k
n
o
wn
s
ev
e
r
ity
an
d
ex
p
e
r
ts
’
in
p
u
ts
.
Fig
u
r
e
2
s
h
o
ws th
at
th
e
n
u
m
b
er
o
f
ac
cid
en
ts
an
d
f
atalities r
ec
o
r
d
ed
in
th
e
f
ir
s
t sev
en
y
ea
r
s
o
f
th
e
last
d
ec
ad
e
f
o
llo
w
s
a
s
im
ilar
tr
en
d
,
ev
en
a
f
ter
th
e
in
cr
ea
s
e
in
r
ailway
tr
af
f
ic
with
th
e
in
tr
o
d
u
ctio
n
o
f
th
e
Ab
u
ja
-
Kad
u
n
a
r
ail
lin
e
in
2
0
1
6
.
T
h
e
ter
r
o
r
attac
k
o
n
th
e
Ab
u
ja
-
Kad
u
n
a
tr
ain
in
2
0
2
2
s
aw
th
e
f
atalit
y
co
u
n
t
p
ea
k
in
g
at
9
,
ev
en
wh
e
n
o
n
l
y
two
r
ailway
ac
cid
en
ts
wer
e
r
ec
o
r
d
e
d
in
th
e
y
ea
r
.
A
s
im
ilar
tr
en
d
co
u
l
d
b
e
o
b
s
er
v
ed
with
th
e
an
n
u
al
in
j
u
r
ies
r
ec
o
r
d
e
d
(
esti
m
ated
)
o
v
er
th
e
last
d
ec
ad
e.
T
h
ese
r
esu
lts
ch
ar
ac
ter
ize
th
e
Nig
er
ian
r
ailway
s
y
s
tem
as
s
em
i
-
v
o
latile,
wh
e
r
e
litt
le
ex
ci
tem
en
ts
r
esu
lt
in
s
ev
er
e
c
o
n
s
eq
u
en
ce
s
.
Alth
o
u
g
h
th
er
e
h
av
e
b
ee
n
s
ce
n
ar
io
s
w
h
er
e
ac
cid
en
ts
h
av
e
b
ee
n
r
ec
o
r
d
ed
with
litt
le
o
r
n
o
ca
s
u
a
lties
,
th
e
r
ep
ea
ted
o
cc
u
r
r
e
n
ce
o
f
f
ewe
r
an
n
u
al
ac
cid
en
ts
with
s
ev
er
e
s
ev
er
ities
ca
lls
f
o
r
co
n
ce
r
n
.
3.
2
.
Co
m
pa
ra
t
iv
e
a
na
ly
s
is
A
d
ir
ec
t
co
m
p
ar
is
o
n
o
f
t
h
e
s
af
ety
p
er
f
o
r
m
a
n
ce
o
f
d
i
v
er
s
e
r
ail
n
etwo
r
k
s
b
ased
o
n
co
r
e
s
af
ety
m
etr
ics
ar
e
n
o
t
f
ea
s
ib
le
d
u
e
t
o
d
if
f
er
en
ce
s
in
s
ize,
tr
af
f
ic
v
o
lu
m
e,
an
d
s
af
ety
in
v
estme
n
ts
p
ec
u
liar
to
ea
ch
n
etwo
r
k
[
2
0
]
,
[
21]
.
Ho
wev
e
r
,
b
y
n
o
r
m
alizin
g
ac
cid
en
t
d
at
a
with
r
esp
ec
t
t
o
th
e
d
is
tan
ce
tr
av
elled
b
y
tr
ain
s
with
in
ea
ch
n
etwo
r
k
,
m
ea
n
in
g
f
u
l
,
an
d
c
o
m
p
a
r
ab
le
in
s
ig
h
t in
t
o
s
af
ety
lev
els ac
r
o
s
s
d
iv
er
s
e
r
ail
n
etwo
r
k
s
co
u
ld
b
e
m
ad
e.
T
h
is
s
tu
d
y
u
s
ed
in
j
u
r
ies
an
d
f
atalities
p
er
m
illi
o
n
tr
ain
k
ilo
m
eter
s
(
p
m
t
k
)
as
n
o
r
m
alizin
g
in
d
ices.
L
o
wer
v
alu
es
o
f
in
j
u
r
ies
an
d
f
atalities
p
m
tk
in
d
icate
a
s
af
er
r
ailway
s
y
s
tem
,
h
ig
h
lig
h
tin
g
ef
f
ec
tiv
e
s
af
et
y
m
ea
s
u
r
es
an
d
in
f
r
astru
ctu
r
e
m
ain
ten
an
ce
[
2
2
]
.
C
o
n
v
e
r
s
ely
,
h
ig
h
er
r
ates
s
ig
n
al
p
o
ten
tial
ar
ea
s
f
o
r
im
p
r
o
v
em
e
n
t in
s
af
ety
p
r
o
to
c
o
ls
,
in
f
r
astru
ctu
r
e
u
p
g
r
ad
es,
o
r
o
p
er
atio
n
al
p
r
o
ce
d
u
r
es.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
2
5
2
-
8
8
1
4
I
n
t J Ad
v
Ap
p
l Sci
,
Vo
l.
1
5
,
No
.
1
,
Ma
r
c
h
2
0
2
6
:
19
-
28
22
Fig
u
r
es
3
an
d
4
p
r
esen
t
th
e
s
af
ety
p
er
f
o
r
m
a
n
ce
o
f
th
r
ee
co
u
n
tr
ies
b
ased
o
n
th
e
ch
o
s
en
in
d
ices.
T
h
e
ch
o
ice
o
f
r
ail
n
etwo
r
k
s
f
o
r
co
m
p
ar
is
o
n
is
g
u
id
ed
p
r
im
ar
ily
b
y
d
ata
ac
ce
s
s
ib
ilit
y
an
d
th
e
l
ev
el
o
f
tech
n
o
lo
g
ica
l
ad
v
an
ce
m
e
n
t
o
f
th
e
r
ail
n
etw
o
r
k
s
.
T
h
e
US
A
a
n
d
UK
ar
e
c
o
n
s
id
er
ed
to
h
av
e
s
o
m
e
o
f
th
e
m
o
s
t
ad
v
an
ce
d
r
ail
s
y
s
tem
s
in
th
e
wo
r
l
d
[
2
3
]
.
T
h
is
co
u
ld
b
e
s
ee
n
in
h
o
w
s
u
ch
n
etwo
r
k
s
o
p
er
ate
with
co
n
s
id
er
ab
ly
l
o
w
an
d
r
elativ
ely
u
n
if
o
r
m
f
atalities
an
d
in
ju
r
ies
p
m
tk
(
Fig
u
r
es
3
a
n
d
4
)
.
T
h
e
s
am
e
co
u
ld
n
o
t
b
e
s
aid
ab
o
u
t
Nig
er
ia,
wh
er
e
th
e
f
atalities
p
m
tk
v
ar
ied
h
ap
h
az
ar
d
ly
o
v
e
r
th
e
last
d
ec
ad
e.
Fo
r
ex
am
p
le,
in
2
0
2
3
,
Nig
er
ia
r
ec
o
r
d
ed
ab
o
u
t
9
2
%
an
d
9
9
%
m
o
r
e
f
at
alities
p
m
tk
th
an
th
e
US
A
an
d
UK,
r
esp
ec
tiv
ely
.
I
n
th
e
s
a
m
e
y
ea
r
,
ab
o
u
t
9
5
%
an
d
4
6
% m
o
r
e
in
j
u
r
ies p
m
tk
wer
e
r
ec
o
r
d
e
d
in
Nig
e
r
ia
th
an
in
th
e
US
A
an
d
UK,
r
esp
ec
tiv
ely
.
Fig
u
r
e
1
.
T
e
m
p
o
r
al
d
is
tr
ib
u
tio
n
o
f
r
ailway
ac
cid
en
ts
in
Nig
e
r
ia
Fig
u
r
e
3
.
C
o
m
p
a
r
ativ
e
tem
p
o
r
al
d
is
tr
ib
u
tio
n
o
f
r
ailway
f
atalities p
m
tk
Fig
u
r
e
4
.
C
o
m
p
a
r
ativ
e
tem
p
o
r
al
d
is
tr
ib
u
tio
n
o
f
r
ailway
in
ju
r
ies p
m
tk
Ho
wev
er
,
Fig
u
r
e
4
s
h
o
ws
m
o
r
e
in
ju
r
ies
p
m
tk
r
ec
o
r
d
ed
in
th
e
UK
th
an
in
Nig
er
ia
o
v
er
s
ev
er
al
y
ea
r
s
in
th
e
last
d
ec
ad
e.
T
h
is
i
s
p
er
h
ap
s
b
ec
au
s
e
m
o
r
e
r
ail
ac
cid
en
ts
in
Nig
er
ia
r
esu
lted
in
f
ata
liti
es
th
an
in
ju
r
ies.
An
o
th
er
lik
ely
r
ea
s
o
n
is
th
e
l
ac
k
o
f
a
n
ac
cu
r
ate
r
ec
o
r
d
o
f
th
e
n
u
m
b
e
r
o
f
v
ictim
s
wh
o
s
u
s
tain
ed
in
ju
r
ies
in
r
ailway
ac
cid
en
ts
.
I
t
is
im
p
o
r
tan
t
to
n
o
te
th
at
th
e
FR
A
an
d
OR
R
in
clu
d
e
all
d
eg
r
ee
s
o
f
in
ju
r
ies
wh
en
r
ep
o
r
tin
g
th
e
n
u
m
b
er
o
f
in
ju
r
i
es
in
r
ailway
ac
cid
en
ts
.
T
h
is
i
s
n
o
t
alwa
y
s
t
h
e
ca
s
e,
as
m
o
s
t
v
ictim
s
with
m
i
n
o
r
in
ju
r
ies in
r
ail
ac
cid
en
ts
in
Ni
g
er
ia
o
f
ten
d
is
ap
p
ea
r
b
ef
o
r
e
th
e
ar
r
iv
al
o
f
an
y
i
n
v
esti
g
atio
n
o
r
em
er
g
e
n
cy
team
.
3.
3
.
F
a
ult
t
re
e
a
na
l
y
s
is
I
n
s
af
ety
r
is
k
ass
ess
m
en
t,
o
n
e
o
f
th
e
cr
itical
s
tag
es
in
th
e
p
r
o
ce
s
s
is
d
ev
elo
p
in
g
a
r
is
k
(
f
au
lt)
tr
ee
.
Su
ch
a
tr
ee
is
u
s
u
ally
d
ev
elo
p
ed
f
r
o
m
h
is
to
r
ical
d
ata
o
f
lik
e
ly
ca
u
s
es
o
f
th
e
to
p
ev
en
t
[
2
4
]
.
I
n
th
is
s
tu
d
y
,
we
u
s
ed
a
t
o
p
-
d
o
wn
ap
p
r
o
ac
h
to
d
ev
elo
p
a
r
is
k
tr
ee
th
at
d
ef
in
e
s
th
e
tax
o
n
o
m
y
o
f
r
ailway
ac
cid
en
ts
in
Nig
e
r
ia.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J Ad
v
Ap
p
l Sci
I
SS
N:
2252
-
8
8
1
4
A
n
a
lysi
s
o
f ra
ilw
a
y
a
cc
id
en
ts
in
N
ig
eria
:
a
d
ec
a
d
e
o
f in
s
ig
h
ts
(
A
liyu
Ma
n
i U
ma
r
)
23
Fig
u
r
e
5
s
h
o
ws
th
e
r
is
k
tr
ee
with
f
o
u
r
lev
els.
At
th
e
to
p
l
ev
el
is
th
e
m
ain
e
v
en
t
(
r
ailway
ac
cid
en
t)
.
T
h
is
is
f
o
llo
wed
b
y
th
e
f
ir
s
t
-
lev
el
e
v
en
ts
th
at
d
ef
in
e
th
e
v
ar
io
u
s
ca
teg
o
r
ies
o
f
r
ailway
ac
ci
d
e
n
ts
r
ec
o
r
d
ed
in
th
e
Nig
er
ian
r
ail
n
etwo
r
k
.
At
th
e
s
ec
o
n
d
ev
en
t
le
v
el,
th
e
lik
ely
s
ce
n
ar
io
s
o
f
co
n
s
eq
u
en
ce
s
o
f
ea
ch
ac
cid
en
t
ty
p
e
ar
e
d
ef
in
e
d
.
T
h
e
tr
ee
en
d
s
with
b
ase
-
lev
el
ev
en
ts
,
w
h
ich
ar
e
th
e
v
ar
i
o
u
s
h
az
ar
d
s
th
at
co
u
ld
lea
d
to
t
h
e
o
cc
u
r
r
e
n
ce
o
f
an
ac
cid
en
t
ty
p
e.
I
t
is
wo
r
th
n
o
tin
g
th
at
th
e
a
s
s
es
s
m
en
t
d
o
es
n
o
t
co
n
s
id
er
a
cc
id
en
ts
th
at
o
cc
u
r
at
r
ailway
s
tatio
n
b
u
ild
in
g
s
,
s
u
ch
as sl
ip
s
an
d
f
alls
.
Fig
u
r
e
5
.
R
is
k
tr
ee
o
f
r
ailway
ac
cid
en
ts
in
Nig
er
ia
T
h
e
r
is
k
tr
ee
p
r
esen
ted
in
Fig
u
r
e
5
co
u
l
d
s
er
v
e
as
th
e
b
u
ild
in
g
b
lo
ck
f
o
r
a
co
m
p
r
e
h
e
n
s
iv
e
r
is
k
ass
es
s
m
en
t,
wh
ich
ty
p
ically
p
r
o
g
r
ess
es
with
ass
ig
n
in
g
p
r
o
b
ab
ilit
y
lik
elih
o
o
d
s
a
n
d
c
o
n
s
eq
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en
ce
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o
f
ea
ch
h
az
ar
d
o
u
s
ev
en
t to
d
eter
m
in
e
t
h
e
r
is
k
lev
el
o
f
th
e
r
ail
n
etwo
r
k
.
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wev
er
,
th
is
is
n
o
t th
e
s
co
p
e
o
f
th
is
s
tu
d
y
.
I
n
th
is
s
tu
d
y
,
we
u
s
ed
th
e
estab
lis
h
ed
r
is
k
tr
ee
to
f
u
r
th
er
in
v
esti
g
ate
th
e
m
o
s
t
f
r
eq
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en
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an
d
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er
e
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t
ca
teg
o
r
y
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th
e
Nig
er
ian
r
ail
n
etwo
r
k
:
in
tr
u
s
io
n
ac
cid
en
ts
.
T
h
is
is
ca
r
r
ied
o
u
t
u
s
in
g
a
r
o
o
t
-
ca
u
s
e
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aly
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is
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d
is
p
r
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ted
in
s
u
b
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ec
tio
n
3
.
4
.
3.
4
.
Ro
o
t
c
a
us
e
a
na
ly
s
is
o
f
ra
ilwa
y
intr
us
io
n a
cc
idents
T
h
e
s
co
p
e
o
f
i
n
tr
u
s
io
n
ac
c
id
en
ts
in
th
is
an
aly
s
is
en
co
m
p
ass
es
all
r
ailway
ac
cid
en
ts
wh
er
e
u
n
au
th
o
r
ized
ac
ce
s
s
to
r
ail
tr
a
ck
s
ca
u
s
es
an
ac
cid
en
t.
As
s
u
ch
,
we
in
clu
d
e
d
all
L
C
ac
cid
e
n
ts
in
th
e
an
aly
s
is
.
T
ab
le
1
p
r
o
v
id
es
f
ac
tu
al
d
etail
s
o
f
s
af
ety
in
cid
en
ts
u
s
ed
f
o
r
t
h
e
an
aly
s
is
.
T
h
e
in
f
o
r
m
atio
n
i
n
T
ab
le
1
was u
s
ed
to
estab
lis
h
s
ets
o
f
im
m
ed
iate
ca
u
s
es
(
I
C
)
,
u
n
d
er
ly
in
g
ca
u
s
e
s
(
UC
)
,
an
d
p
r
e
v
en
tiv
e
m
ea
s
u
r
es
(
PM)
as
s
h
o
w
n
in
T
ab
le
2
.
Fig
u
r
e
6
p
r
esen
ts
th
e
r
o
o
t c
a
u
s
e
m
ap
p
i
n
g
o
f
ev
en
ts
to
ca
u
s
es a
n
d
PM
.
Ab
o
u
t
6
2
%
o
f
all
i
n
tr
u
s
io
n
ac
cid
en
ts
wer
e
ca
u
s
ed
b
y
n
e
g
lig
en
ce
o
f
r
o
ad
u
s
er
s
.
An
UC
is
a
lack
o
f
s
af
ety
ed
u
ca
tio
n
f
o
r
r
o
a
d
u
s
er
s
o
n
th
e
s
af
e
u
s
e
o
f
lev
el
c
r
o
s
s
in
g
s
.
T
h
is
is
ev
i
d
en
t
f
r
o
m
th
e
ev
en
ts
’
f
ac
ts
o
u
tlin
ed
in
T
ab
le
1
,
wh
ich
s
h
o
w
th
at
m
o
s
t
lev
el
-
cr
o
s
s
in
g
a
cc
id
en
ts
o
cc
u
r
r
e
d
b
ec
a
u
s
e
th
e
r
o
ad
u
s
er
b
eliev
e
d
th
ey
co
u
ld
b
ea
t
th
e
tr
ain
to
th
e
o
th
er
en
d
o
f
th
e
lev
el
-
c
r
o
s
s
in
g
.
As
s
u
ch
,
awa
r
en
ess
ca
m
p
aig
n
s
o
n
LC
s
af
ety
ar
e
n
ee
d
ed
,
p
ar
tic
u
lar
ly
in
co
m
m
u
n
ities
n
ea
r
r
ailway
lin
es.
T
h
e
f
in
d
in
g
s
in
[
2
5
]
also
s
u
p
p
o
r
t
th
is
ass
er
tio
n
.
T
h
e
lo
n
g
s
lu
m
b
er
o
f
r
ailway
o
p
er
atio
n
s
o
v
e
r
th
e
p
ast
d
ec
ad
e
n
ec
ess
itate
s
in
ten
s
iv
e
ef
f
o
r
ts
to
r
e
-
ed
u
ca
te
r
o
a
d
u
s
er
s
o
n
s
af
ety
at
h
ig
h
way
-
r
ail
cr
o
s
s
in
g
s
.
Oth
er
s
ig
n
if
ican
t
UC
o
f
m
o
s
t
in
tr
u
s
io
n
ac
cid
en
ts
ar
e
in
ad
eq
u
ate
d
esig
n
a
n
d
p
o
o
r
m
ain
ten
an
ce
cu
ltu
r
e.
C
r
itical
lo
ca
tio
n
s
alo
n
g
r
ail
lin
es
h
a
v
e
b
ee
n
id
en
tif
ied
wh
er
e
in
a
p
p
r
o
p
r
iate
h
i
g
h
way
-
r
ail
in
ter
ac
tio
n
s
wer
e
estab
lis
h
ed
.
C
o
n
g
ested
co
m
m
er
cial
h
u
b
s
wh
er
e
a
g
r
ad
e
s
ep
ar
atio
n
is
th
e
o
n
ly
s
a
f
e
alter
n
ativ
e
wer
e
d
esig
n
ed
with
lev
el
cr
o
s
s
in
g
s
.
Similar
ly
,
th
er
e
ar
e
in
s
tan
ce
s
wh
er
e
d
en
s
ely
p
o
p
u
late
d
n
eig
h
b
o
r
h
o
o
d
s
h
av
e
n
o
L
C
to
ac
ce
s
s
h
ig
h
way
s
.
T
h
ese
g
av
e
r
is
e
to
illeg
al
c
r
o
s
s
in
g
s
cr
ea
ted
b
y
r
esid
en
ts
,
a
s
o
u
r
ce
o
f
s
ev
er
al
in
tr
u
s
io
n
ac
cid
en
ts
.
Oth
er
ca
u
s
es
r
esu
ltin
g
f
r
o
m
p
o
o
r
d
esig
n
in
clu
d
e
th
e
n
o
n
-
p
r
o
v
is
io
n
o
f
p
ed
estrian
an
d
an
im
a
l
cr
o
s
s
in
g
s
alo
n
g
s
tr
ateg
ic
lo
ca
tio
n
s
.
I
n
s
tan
ce
s
h
av
e
b
ee
n
r
e
co
r
d
ed
wh
e
r
e
a
lar
g
e
h
er
d
o
f
ca
ttle
in
tr
u
d
ed
in
to
th
e
r
ail
tr
ac
k
d
u
e
to
a
lac
k
o
f
a
n
im
al
cr
o
s
s
in
g
alo
n
g
a
k
n
o
wn
h
er
d
er
’
s
r
o
u
te.
Evaluation Warning : The document was created with Spire.PDF for Python.
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24
T
ab
le
1
.
Factu
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r
ailway
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tr
u
s
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en
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r
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e
l
o
a
d
i
n
g
l
i
mi
t
s.
PM
o
f
r
ailway
in
tr
u
s
io
n
ac
cid
en
ts
in
Nig
er
ia
r
e
q
u
ir
e
i
n
f
r
astr
u
ctu
r
e
u
p
g
r
a
d
es
an
d
m
ass
iv
e
awa
r
en
ess
ca
m
p
aig
n
s
o
n
r
ailway
s
af
ety
,
as
s
h
o
wn
in
Fig
u
r
e
6
.
Fig
u
r
e
6
(
a)
s
h
o
ws
th
e
s
af
ety
e
v
en
ts
m
ap
p
in
g
to
im
m
ed
iate
an
d
UC
,
wh
ile
Fi
g
u
r
e
6
(
b
)
s
h
o
ws
th
e
s
af
ety
e
v
en
ts
m
ap
p
i
n
g
to
PM.
G
r
ab
u
š
ić
an
d
B
ar
ić
[
2
6
]
id
en
tifie
d
in
f
r
astru
ctu
r
e
u
p
g
r
a
d
e
to
b
e
th
e
k
ey
PM
to
r
ailwa
y
in
tr
u
s
io
n
ac
cid
en
ts
.
C
u
r
r
e
n
t
ly
,
th
e
L
a
g
o
s
State
Go
v
er
n
m
e
n
t
,
with
s
u
p
p
o
r
t
f
r
o
m
th
e
Fed
er
al
G
o
v
er
n
m
en
t
o
f
Nig
er
ia
,
h
as
i
n
itiated
th
e
p
r
o
ce
s
s
o
f
r
ep
lacin
g
lev
el
cr
o
s
s
in
g
s
with
g
r
ad
e
s
ep
ar
atio
n
at
s
tr
ateg
ic
lo
ca
tio
n
s
in
th
e
s
tate.
T
h
is
ef
f
o
r
t
m
u
s
t
b
e
co
m
p
lem
en
ted
b
y
s
tr
ict
en
f
o
r
ce
m
en
t
o
f
s
af
ety
laws
th
at
will
en
s
u
r
e
th
e
er
ad
icatio
n
o
f
illeg
al
cr
o
s
s
in
g
s
an
d
co
m
m
er
cial
ac
tiv
ities
n
ea
r
r
ail
tr
ac
k
s
.
Si
m
ilar
ly
,
s
ev
er
al
in
t
r
u
s
io
n
ac
ci
d
en
ts
co
u
ld
b
e
a
v
o
id
e
d
th
r
o
u
g
h
s
af
ety
awa
r
en
ess
ca
m
p
aig
n
s
f
o
r
r
o
ad
u
s
er
s
an
d
co
m
m
u
n
ities
clo
s
e
to
r
ail
lin
es.
Mo
s
t
r
o
ad
/r
o
ad
-
r
ail
in
t
er
s
ec
tio
n
p
o
in
ts
in
Nig
er
ia
ar
e
h
awk
in
g
an
d
tem
p
o
r
ar
y
co
m
m
er
cial
s
talls
h
o
ts
p
o
ts
.
Usu
ally
,
th
ese
ac
tiv
ities
ar
e
co
n
d
u
cted
r
ig
h
t
o
n
th
e
r
o
ad
wa
y
/r
ail
tr
ac
k
s
.
Mo
s
t
lev
el
cr
o
s
s
in
g
s
,
esp
ec
ially
th
o
s
e
alo
n
g
th
e
C
ap
e
g
au
g
e
li
n
es,
h
av
e
n
o
ac
tiv
e
war
n
in
g
s
y
s
tem
s
.
At
th
ese
lev
el
cr
o
s
s
in
g
s
,
th
e
o
n
ly
war
n
i
n
g
s
y
s
tem
to
an
ap
p
r
o
ac
h
i
n
g
tr
ain
is
its
b
last
in
g
h
o
r
n
.
As s
u
ch
,
tr
ad
er
s
ar
e
o
f
te
n
ca
u
g
h
t u
n
awa
r
es.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
n
t J Ad
v
Ap
p
l Sci
I
SS
N:
2252
-
8
8
1
4
A
n
a
lysi
s
o
f ra
ilw
a
y
a
cc
id
en
ts
in
N
ig
eria
:
a
d
ec
a
d
e
o
f in
s
ig
h
ts
(
A
liyu
Ma
n
i U
ma
r
)
25
(
a)
(
b
)
Fig
u
r
e
2
.
R
o
o
t c
a
u
s
e
m
ap
p
in
g
of
(
a)
s
af
ety
ev
en
ts
m
ap
p
in
g
t
o
im
m
ed
iate
an
d
UC
an
d
(
b
)
s
af
ety
ev
en
ts
m
ap
p
in
g
to
PM
4.
CO
NCLU
SI
O
N
T
h
is
s
tu
d
y
estab
lis
h
ed
th
e
tem
p
o
r
al
d
is
tr
ib
u
tio
n
an
d
co
m
p
ar
ativ
e
an
aly
s
is
o
f
r
ail
ac
ci
d
en
ts
in
th
e
Nig
er
ian
r
ail
n
etwo
r
k
o
v
er
th
e
last
d
ec
ad
e.
A
r
o
o
t
ca
u
s
e
an
al
y
s
is
o
f
th
e
m
o
s
t
o
cc
u
r
r
in
g
ac
c
id
en
t
ca
teg
o
r
y
was
p
er
f
o
r
m
ed
,
an
d
ac
tio
n
ab
le
PM
wer
e
p
r
o
p
o
s
ed
.
T
h
e
tem
p
o
r
al
d
is
tr
ib
u
tio
n
o
f
ac
cid
en
ts
s
u
g
g
ests
th
at
th
e
Nig
er
ian
r
ail
n
etwo
r
k
is
s
em
i
-
v
o
latile,
with
f
ew
ac
cid
en
ts
r
e
s
u
ltin
g
in
s
ev
er
e
co
n
s
eq
u
en
ce
s
.
T
h
e
Nig
er
ian
r
ail
n
etwo
r
k
r
ec
o
r
d
e
d
co
n
s
id
er
a
b
l
y
h
ig
h
e
r
f
atalities
an
d
in
ju
r
ies
p
er
m
illi
o
n
tr
ain
k
ilo
m
eter
s
th
an
th
e
US
A
an
d
UK
r
ail
n
etwo
r
k
s
.
T
h
e
estab
lis
h
ed
r
is
k
tr
ee
r
ev
ea
led
s
ix
r
ailway
ac
cid
en
t
ca
teg
o
r
ies
r
ec
o
r
d
ed
o
v
er
th
e
last
d
ec
ad
e.
Six
im
m
e
d
iate
an
d
e
lev
en
UC
o
f
r
ailway
in
t
r
u
s
io
n
ac
cid
en
ts
wer
e
id
e
n
tifie
d
.
Ab
o
u
t
6
2
%
o
f
all
in
tr
u
s
io
n
ac
cid
en
ts
in
th
e
Nig
er
ian
r
ail
n
etwo
r
k
wer
e
ca
u
s
ed
b
y
n
eg
lig
e
n
ce
o
f
r
o
a
d
u
s
er
s
.
Sev
er
al
ac
tio
n
ab
le
PM
h
av
e
b
ee
n
p
r
o
p
o
s
ed
f
o
r
ea
ch
id
en
tifie
d
UC
b
ased
o
n
b
est
p
r
ac
tices
f
r
o
m
d
ev
elo
p
ed
r
ail
n
etwo
r
k
s
.
I
n
f
r
astru
ctu
r
e
u
p
g
r
a
d
es
an
d
s
af
ety
awa
r
en
ess
ca
m
p
aig
n
s
h
av
e
b
ee
n
id
e
n
tifie
d
as
th
e
m
o
s
t
ef
f
ec
tiv
e
PM
f
o
r
r
ailway
in
tr
u
s
io
n
ac
cid
e
n
ts
in
Nig
er
ia.
5.
F
UT
UR
E
RE
SE
A
RCH
Fu
tu
r
e
r
esear
ch
co
u
ld
ex
p
lo
r
e
th
e
s
af
ety
ev
alu
atio
n
o
f
th
e
Nig
er
ian
r
ail
n
etwo
r
k
th
r
o
u
g
h
q
u
an
titativ
e
r
is
k
ass
ess
m
en
t
tech
n
iq
u
es.
T
h
e
r
is
k
tr
ee
d
ev
elo
p
e
d
in
t
h
is
s
tu
d
y
co
u
ld
s
er
v
e
as
a
s
t
ar
tin
g
p
o
in
t
f
o
r
r
is
k
q
u
an
tific
atio
n
.
Similar
ly
,
th
e
v
ar
io
u
s
ac
cid
e
n
t
ca
teg
o
r
ies
id
en
tifie
d
in
th
is
s
tu
d
y
c
o
u
ld
b
e
f
u
r
th
e
r
in
v
esti
g
ated
to
estab
lis
h
in
ter
r
elatio
n
s
h
ip
s
b
etwe
en
d
if
f
er
e
n
t
s
af
ety
ev
e
n
ts
an
d
p
r
o
v
id
e
h
o
lis
tic
PM
th
at
co
u
ld
im
p
r
o
v
e
th
e
o
v
er
all
s
af
ety
o
u
tlo
o
k
o
f
th
e
Nig
er
ian
r
ail
n
etwo
r
k
.
F
UNDING
I
NF
O
R
M
A
T
I
O
N
T
h
is
r
esear
ch
was
f
u
n
d
e
d
b
y
th
e
Fu
n
d
am
en
tal
R
esear
ch
Gr
an
t
Sch
em
e
(
FR
GS)
,
g
r
a
n
t
n
u
m
b
er
FR
GS
/1
/2
0
2
3
/TK
0
2
/UT
M/0
2
/
4
,
f
u
n
d
ed
b
y
th
e
Min
is
tr
y
o
f
Hig
h
er
E
d
u
ca
tio
n
(
MO
HE
)
,
Ma
lay
s
ia.
T
h
e
f
ir
s
t
au
th
o
r
ac
k
n
o
wled
g
es
f
in
a
n
cial
s
u
p
p
o
r
t
f
r
o
m
th
e
Petr
o
leu
m
T
ec
h
n
o
lo
g
y
Dev
el
o
p
m
e
n
t
Fu
n
d
(
PTDF)
,
Nig
e
r
ia
,
f
o
r
h
is
Ph
.
D
.
p
r
o
g
r
am
m
e
with
awa
r
d
I
D
2
2
PHD0
7
4
.
AUTHO
R
CO
NT
RI
B
UT
I
O
NS ST
A
T
E
M
E
N
T
T
h
is
jo
u
r
n
al
u
s
es
th
e
C
o
n
tr
ib
u
to
r
R
o
les
T
ax
o
n
o
m
y
(
C
R
ed
iT)
to
r
ec
o
g
n
ize
in
d
iv
id
u
al
au
th
o
r
co
n
tr
ib
u
tio
n
s
,
r
ed
u
ce
au
th
o
r
s
h
ip
d
is
p
u
tes,
an
d
f
ac
ilit
ate
co
llab
o
r
atio
n
.
Evaluation Warning : The document was created with Spire.PDF for Python.
I
SS
N
:
2
2
5
2
-
8
8
1
4
I
n
t J Ad
v
Ap
p
l Sci
,
Vo
l.
1
5
,
No
.
1
,
Ma
r
c
h
2
0
2
6
:
19
-
28
26
Na
m
e
o
f
Aut
ho
r
C
M
So
Va
Fo
I
R
D
O
E
Vi
Su
P
Fu
Aliy
u
Ma
n
i U
m
ar
✓
✓
✓
✓
✓
✓
✓
✓
✓
Mo
h
d
Kh
air
u
l A
f
za
n
Mo
h
d
L
az
i
✓
✓
✓
✓
✓
✓
Sit
ti Asm
ah
Has
s
an
✓
✓
✓
✓
✓
✓
Han
in
i I
ly
an
a
C
h
e
Hash
im
✓
✓
✓
✓
✓
✓
Yin
g
g
u
i Z
h
a
n
g
✓
✓
✓
✓
✓
✓
✓
Nu
r
a
Sh
eh
u
Aliy
u
Yar
o
✓
✓
✓
✓
✓
✓
Ad
am
Ad
o
Sab
ar
i
✓
✓
✓
✓
✓
✓
Su
r
ajo
Ab
u
b
a
k
ar
W
ad
a
✓
✓
✓
✓
✓
C
:
C
o
n
c
e
p
t
u
a
l
i
z
a
t
i
o
n
M
:
M
e
t
h
o
d
o
l
o
g
y
So
:
So
f
t
w
a
r
e
Va
:
Va
l
i
d
a
t
i
o
n
Fo
:
Fo
r
mal
a
n
a
l
y
s
i
s
I
:
I
n
v
e
s
t
i
g
a
t
i
o
n
R
:
R
e
so
u
r
c
e
s
D
:
D
a
t
a
C
u
r
a
t
i
o
n
O
:
W
r
i
t
i
n
g
-
O
r
i
g
i
n
a
l
D
r
a
f
t
E
:
W
r
i
t
i
n
g
-
R
e
v
i
e
w
&
E
d
i
t
i
n
g
Vi
:
Vi
su
a
l
i
z
a
t
i
o
n
Su
:
Su
p
e
r
v
i
s
i
o
n
P
:
P
r
o
j
e
c
t
a
d
mi
n
i
st
r
a
t
i
o
n
Fu
:
Fu
n
d
i
n
g
a
c
q
u
i
si
t
i
o
n
CO
NF
L
I
C
T
O
F
I
N
T
E
R
E
S
T
ST
A
T
E
M
E
NT
T
h
e
au
t
h
o
r
s
d
ec
lar
e
th
at
th
er
e
is
n
o
co
n
f
lict
o
f
in
ter
est
b
e
twee
n
th
em
r
eg
ar
d
in
g
th
e
p
u
b
licatio
n
o
f
th
is
ar
ticle.
I
NF
O
RM
E
D
CO
NS
E
N
T
T
h
is
s
tu
d
y
d
o
es n
o
t in
v
o
l
v
e
h
u
m
an
s
u
b
jects o
r
p
er
s
o
n
al
in
f
o
r
m
atio
n
r
e
q
u
ir
in
g
in
f
o
r
m
ed
c
o
n
s
en
t.
E
T
H
I
CAL AP
P
RO
V
AL
T
h
is
s
tu
d
y
d
o
es n
o
t in
v
o
l
v
e
h
u
m
an
s
u
b
jects o
r
a
n
im
al
ex
p
e
r
im
en
ts
.
DATA AV
AI
L
AB
I
L
I
T
Y
T
h
e
au
th
o
r
s
co
n
f
ir
m
th
at
th
e
d
ata
s
u
p
p
o
r
tin
g
th
e
f
in
d
in
g
s
o
f
th
is
s
tu
d
y
ar
e
av
ailab
le
with
in
th
e
ar
ticle
[
an
d
/o
r
its
s
u
p
p
lem
en
tar
y
m
ater
ials
]
.
RE
F
E
R
E
NC
E
S
[
1
]
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ics
,
a
n
d
h
u
m
a
n
fa
c
to
rs.
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c
a
n
b
e
c
o
n
tac
ted
a
t
e
m
a
il
:
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o
h
d
k
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ir
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lafz
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n
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tm.m
y
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m
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in
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th
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Un
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o
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UK
.
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h
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y
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o
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r
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t
Un
i
v
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n
o
lo
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M
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h
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tere
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h
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c
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o
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tac
ted
a
t
e
m
a
il
:
sa
sm
a
h
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tm.
m
y
.
Evaluation Warning : The document was created with Spire.PDF for Python.
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.
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c
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d
u
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c
n
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h
e
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y
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d
h
is
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h
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.
fro
m
Un
i
v
e
rsiti
Te
k
n
o
lo
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P
e
tr
o
n
a
s,
M
a
lay
sia
.
He
is a res
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a
rc
h
fe
ll
o
w at t
h
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De
p
a
rtme
n
t
o
f
Civ
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m
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l
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s,
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r
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h
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p
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teria
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c
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tac
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h
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Un
iv
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o
f
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b
a
m
a
in
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c
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o
f
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n
t
ra
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o
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t
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Un
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v
e
rsity
,
Ch
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n
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sh
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in
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.
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is
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lec
tu
re
r
a
t
Ah
m
a
d
u
Be
ll
o
Un
iv
e
rsity
,
Zaria
,
Nig
e
ria.
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re
se
a
rc
h
fo
c
u
se
s
o
n
h
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m
a
n
fa
c
to
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fe
ty
c
u
lt
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re
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stru
c
t
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ra
l
re
li
a
b
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li
ty
,
a
n
d
re
sili
e
n
c
e
.
He
c
a
n
b
e
c
o
n
tac
te
d
a
t
e
m
a
il
:
srjwa
d
a
@g
m
a
il
.
c
o
m
.
Evaluation Warning : The document was created with Spire.PDF for Python.