
combine three centrality measures (i.e., C
D
, C
B
, and C
C
)
together in our algorithm. Then, the complete graph is con-
verted to a matrix, and the regulation is performed on it for
further computation. Finally, a ranked list of nodes can be
generated by applying a random walk on the complete model
of preference relations.
It should be noted that, in this paper, only three basic
centrality measures are taken into account in the algorithm.
However, the above framework is a scalable model for evalu-
ating node infl uences. That is, besides the basic measures,
some other advanced measures can also be adopted in it.
Each measure has its own advantages and limitations in
representing the influences of nodes, so the complementarity
should be considered when choosing the measures for use in
our framework.
3.2. The Technical Details
3.2.1. Analysis on Partial Preference Relations. In order to
address the technical details of our proposed algorithm, a
small network (graph) is used as a running example. As
shown in Figure 2, the whole network consists of seven
nodes and eight undirected edges. Intuitively, node 3 is
the most influential node in this network, and node 1 is
the second one. Node 7 should be the weakest one with
respect to the influence or the ability of information
spreading. Furthermore, node 5 has higher influence than
node 7, but is lower than other remainders. However, the
influences of nodes 2, 4, and 6 are difficult to distinguish
only by subjective assessment.
According to the definitions in Section 2.2, three mea-
sures of each node in Figure 2 can be calculated and
illustrated in Table 1. For the measure of degree central-
ity ( C
D
), node 3 has the max degree (i.e., 4) and node 7’s
degree is just only one. If we rank nodes in accordance
with this indicator, the order can be expressed as below:
3 ⟶ 1 ⟶ 2 ~ 4 ~ 5 ~ 6 ⟶ 7. Here, i⟶ j means node
i has higher influence than node j, and i~j means nodes i
and j have no significant difference in influence. Although
the above ranking result about C
D
is consistent with the
subjective and intuitive judgment, quite a few nodes have
the same degree so that it is hard to provide an accurate
order. For the running example in Figure 2, it is difficult to
distinguish nodes 2, 4, 5, and 6 in a strictly ordered relation.
With regard to the basic measure of betweenne ss central-
ity (C
B
), node 3 also has the highest value, but the between-
ness values of nodes 2 and 7 are both zero. The rank about
C
B
is as follows: 3 ⟶ 6 ⟶ 1 ⟶ 4 ⟶ 5 ⟶ 2 ~ 7.
Since the betweenness centrality mainly focuses on the
connection feature of nodes and ignores the spreading
breadth of node influences, the above rank has little conflict
to the subjective result.
For the third measure, i.e., closeness centrality (C
C
), it is
defined as the inverse of farness, which in turn is the sum
of distances from the current node to all other nodes. In this
example, the rank of all seven nodes with respect to C
C
is
3 ⟶ 1 ⟶ 2 ~ 4 ~ 6 ⟶ 5 ⟶ 7. We can find that
there are still quite a few nodes in the same order, such
as nodes 2, 4, and 6 here.
As mentioned above, the basic measures of node influ-
ences merely re flect one aspect of information (or disease)
spreading features and behaviors. On the other hand, it
may be di fficult to distinguish the order of some nodes due
to the same metric values. In the paper, we present a new
ranking algorithm by comprehensively considering the above
... ... ...
Preference relation analysis on the single measure
e 1st measure
of node influences
e /th measure
of node influences
Analyze the
preference relation
between two nodes
Analyze the
preference relation
between two nodes
Construct the sub-
graph of preference
relation
Construct the sub-
graph of preference
relation
e ranked list of
nodes about their
influences
Apply random walk
to rank nodes
Comprehensive analysis
for preference relations
Construct the
complete graph of
preference relation
Regulate the matrix
of the complete
graph
Figure 1: The overall framework for ranking nodes according to their influences.
1
2
3
5
46
7
Figure 2: A running example for evaluating node influences.
4 Complexity