Geoscience Reference
In-Depth Information
9
0
:
9
þ
0
:
48
0
:
:
ð
:
Þ
0
65
¼
4
15
ð
Þ
A full nationwide TransNIEMO was applied to study the economic impacts of
three hypothetical road closure scenarios: two bridge service disruptions on the
Mississippi River and one tunnel service disruption in the Rocky Mountains.
4.4
FlexNIEMO
FlexNIEMO is used to construct period-to-period versions of NIEMO. The
approach developed recently by Park et al. (
2011b
) allows the fixed coefficients
in the input-output world to be continuously modified, reflecting previous eco-
nomic events and changes in interindustry relations. For example, a problem using
the supply-side model is how to reflect demand-side adjustments during the recov-
ery. With the supply-side FlexNIEMO, some of the major shortcomings inherent in
the I-O model can be overcome. Based on supply and demand-driven economic
input-output models suggested by Park et al. (
2011b
) and Gordon et al. (
2009
),
where the entire detailed modeling approaches are found, we summarize the
procedure here.
The FlexNIEMO approach begins with estimating total impacts. Let
X
s
(
t
) and
X
d
(
t
) be the total input row vector and the total output column vector respectively
for various commodity and service sectors. Dropping off the subscript
NIEMO
from
the previous equations, the total input vector is the sum of inter-industry sales (
A
(
t
)
X
s
(
t
)) and total final demands (
F
(
t
)), and the total output vector is the sum of inter-
industry purchases (
B
(
t
)
X
d
(
t
)) and total value added factors (
W
(
t
)).
X
s
X
s
ðÞ
¼
t
At
ðÞ
ðÞþ
t
Ft
ðÞ
ð
4
:
16
Þ
X
d
X
d
ðÞ
¼
t
Bt
ðÞ
ðÞþ
t
Vt
ðÞ
ð
4
:
17
Þ
where
A(t)
is a
X
S
(t)
-based requirement matrix composed of a technical flows
matrix for industries within a region,
Z
(
t
)
, and a block diagonal matrix of inter-
regional trade flows,
C
s
(t)
. It is, defined as
,
C
s
At
ðÞ
¼
ʓ
t
Zt
½
ðÞ
ðÞ
t
ð
4
:
18
Þ
A column vector
F(t)
represents region specific final demand changes. Similarly,
B(t)
is a
X
d
(t)
-based requirement matrix composed of a technical flows matrix for
industries,
Z
(
t
)
, and a block diagonal matrix of inter-regional trade flows,
C
d
(t)
,
defined as
,
C
d
Bt
ðÞ
¼
ʘ
t
Zt
ðÞ
ðÞ
t
ð
:
Þ
4
19
In addition,
V(t)
is a row vector of region specific changes in value added. Note
that
ʓ
t
and
ʘ
t
are matrix functions that are used to update the requirement matrices
