(4) A certain order of label updating is given which can expedite the convergence process. The rest of the paper is organized as follows. Section 2 introduces
α-degree neighborhood networks, as well as the α-degree neighborhood impact formula. Section 3 describes the working principle and steps of the proposed algorithm α-NILP in detail. selleck product Section 4 presents the experimental results and the analysis. Finally, Section 5 concludes the paper. 2. α-Degree Neighborhood Impact Given a network G = (V, E), where V is the set of nodes and E is the set of edges, and the task of network community detection is to find densely connected subgraphs in G. The label propagation method is applied here to implement automatic community detection . Taking nodes as the basic computing units, we initialize every node with a unique label and let the labels propagate in a certain order through the network. In order to make densely connected nodes have the same labels, we take the local link structure into consideration. In this section, some related definitions are given as follows. Definition 1 (α-degree neighbor). — Let G = (V, E) be an undirected network, where V is a set of nodes and E is a set of edges. Let u, v ∈ V. If the length of the shortest path from node u to v is α, then node v is called the α-degree neighbor of
node u, denoted by u→αv. Γ(u)=v∣v∈V∧u→αv is the set containing all the α-degree neighbors of u. It is obvious that the definition of α-degree neighbor is symmetrical, which means if node u is the α-degree neighbor of node v, then so is node v to node u. Particularly, node u is the 0-degree neighbor of itself. Definition 2 (α-degree neighborhood network). — Let G = (V, E) be an undirected network with node u, v ∈ V and V′=v∣v∈V∧u→ϵv∧0≤ϵ≤α. The spanning subgraph G′ = (V′, E′), which is composed
of V′ and E′ = u, v∣u, v ∈ V′∧u, v ∈ E, is called the α-degree neighborhood network of node u. As shown in Figure 1, nodes 2–6, which are the neighbors of node 1 and are called its 1-degree neighborhood nodes, form the 1-degree neighborhood network of node Anacetrapib 1 with all the incident edges of those nodes. Node 7 is a 2-degree neighbor of node 1, and the spanning subgraph composed of nodes 1–7 is a 2-degree neighborhood network of node 1. In general, we can view an α-degree network as a complete closed system constituted by an initiating center node and its surrounding counterparts and their incident edges. In this system, starting from a certain node u, we measure and analyze its local connection density via its α-degree neighbors and neighborhood network to yield the average degree of impact on all its surrounding nodes. Figure 1 A sample network. In a real network, a node affects its neighbors through its edges. In an unweighted network, a center node u wields precisely identical influence on its every neighbor.