For a node v, its PageRank value pr(v) is computed as follows: where |V | is the number of nodes in the BINet, N (v) denotes the set of nodes adjacent to v, d is the damping factor and is set to 0.85, , which is the normalized weight of the edge between v Intuitively, a node with a high PageRank value is usually important and likely to be the key node that indicates the key information of an event.
we rank nodes in the BINet by their PageRank value and choose the node which has the highest PageRank value and does not belong to any community as a key node to construct a community E around it with its closely related nodes: where v is the node with the highest PageRank value and does not belong to any community,ω v,u is the normalized weight of the edge between v and u, and σ N is the threshold for selecting closely related nodes.