|
|
|
|
|
Clustering CoefficientWatts and Strogatz (1998) introduce the clustering coefficient graph measure to determine whether or not a graph is a small-world network. First, let us define a graph in terms of a set of vertices and a set of edges , where denotes an edge between vertices and . Below we assume , and are members of V. We define the neighbourhood N for a vertex as its immediately connected neighbours as follows: The degree of vertex is the number of vertices in its neighbourhood . The clustering coefficient for a vertex is the proportion of links between the vertices within its neighbourhood divided by the number of links that could possibly exist between them. For a directed graph, is distinct from , and therefore for each neighbourhood there are links that could exist among the vertices within the neighbourhood. Thus, the clustering coefficient is given as: This measure is 1 if every neighbour connected to is also connected to every other vertex within the neighbourhood, and 0 if no vertex that is connected to connects to any other vertex that is connected to . The clustering coefficient for the whole system is given by Watts and Strogatz as the average of the clustering coefficient for each vertex: References - Watts, D. J. and Strogatz, S. H. (1998). Collective dynamics of 'small-world' networks. Nature 393, 440--442 (4 June 1998).
|
 |
|
| Copyright 2005-2009 OnPedia.com. All Rights Reserved |
|
|