Information Technology Reference
In-Depth Information
Fig. 5.8 v
0
is the betweeness
center because in this
network, the one whose path
is crossed the most by the
shortest paths of the every
pair of vertex is
v
0
n
0
n
1
draw the shortest path of each pair, the vertex whose path is crossed the most times
is
v
0
. The betweeness center of the network is the vertex which is crossed the most
times by the shortest paths of every pair of the network. In Fig.
5.8
,
v
0
is the
betweeness centrality.
Betweeness centrality is calculated as follows.
P
P
N
i
S
1
g
ð
i
S
i
T
Þ
N
i
S
i
T
i
S
¼
1
;i
S
6¼i
i
T
¼
1
;i
T
6¼i
b
i
¼
ð
N
1
Þð
N
2
Þ=
2
5.8.3.2 Division of the Network by Betweeness Centrality
Deleting the vertex of betweeness center in the network, the network becomes
divided to be the set of clusters (Girvan and Newman
2002
). This dividing is a
coarse method of finding communities. As a method to control the size of the
phenomenon of information cascading, we can use the splitting of the network by
betweeness centrality (Fig.
5.9
).
The most influential person is a person who has many followers. However,
the most important factor of wide area information cascading is a person of the
betweeness center of the social network. Therefore a person who has both property
is an important person to control the information cascading.
