Biomedical Engineering Reference
In-Depth Information
Figure 1
. Characterizing a simple network: in the figure, both nodes,
i
and
j
, have three links (
k
= 3). The shortest path between these nodes, indicated in blue, has length
l
ij
= 3.
Table 1
Parameter Definition
Total number of nodes
N
Degree of node
i
k
i
Shortest path length
l
ij
2
N
l
=
l
Mean path length
ij
NN
(
)
ki
v
i
=
1
2
(
n
C
=
i
Clustering coefficent
i
kk
)
i
i
1
=
N
C
C
Mean clustering coefficient
i
N
i
=
1
offering a measure of the network's navigability. A network that can be
"crossed" by a relatively small number of steps is often referred to as displaying
the "small world" property, first illustrated on social networks, indicating that
two randomly chosen individuals can be connected by only six intermediate
acquaintances (36).
Nodes in many real systems exhibit a tendency to cluster, which can be
quantified using the clustering coefficient (60), a measure of the degree to which
