wiki/wikipedia/1008.txt

Hierarchical clustering is one method for finding community structures in a network. The technique arranges the network into a hierarchy of groups according to a specified weight function. The data can then be represented in a tree structure known as a dendrogram. Hierarchical clustering can either be agglomerative or divisive depending on whether one proceeds through the algorithm by adding links to or removing links from the network, respectively. One divisive technique is the Girvan–Newman algorithm.

<!-- Image with unknown copyright status removed: thumb|right|Fig. 1: Example of a dendrogram constructed using a hierarchical clustering algorithm.

Edge betweenness centrality has been used successfully as a weight in the Girvan–Newman algorithm. This method provides a computationally less-costly alternative to the Girvan-Newman algorithm while yielding similar results.