How about using this paper by our own Dr Nepusz? :) http://arxiv.org/abs/0707.1646
Gabor On Tue, Jun 24, 2014 at 5:24 AM, Stephan Schlögl <[email protected]> wrote: > Hello all, > I'm doing sna on a network of Twitter users and the follower relations > between them (using igraph for R). The network reveals clusters that can be > easily explained by country or at least the language they use. > I'm interested in the users who connect those clusters and looking for a > metric that can find them. As for now I've been thinking of two approaches: > > Betweenness centrality > BC somehow represents the concept of "bridges" I am looking for. Since my > interest lies especially in the bridges between clusters I'd just base this > calculation on the paths between clusters. e.g. If users A and B are part of > cluster 1 and C and D part of Cluster 2, I'd compute the shortest paths for > A-C, A-D, B-C,B-D but not A-B,C-D. I thought this would reduce number of > paths considerably and make BC feasible for the network (IGRAPH DNW- 11206 > 1991845 --). Some simple estimations show that it does not. It would still > take about half a year to compute that. > > Modularity on the level of vertices > I understand that modularity is a metric for graphs and their partitions as > a whole. But can it be used for individual nodes anyway? The "fraction of > edges" within a cluster could be based on the neighborhood of each > individual node "minus the expected value of the same quantity in a network > with the same community divisions but random connections between the > vertices" (Newman/Girvan 2004). A low modularity on node level would then > mean that the node is some sort of bridge and nodes with high modularity are > the least "cosmopolitan" ones. > > So, here are my questions: > Do you think one of these approaches measures what I'm looking for > (Bridges)? > Are there other metrics I could use for this? > Is modularity on the level of nodes possible or even already implemented in > igraph? > If the modularity on the level of nodes is doable but not implemented, how > is the "expected value [..] in a network of with the same community > divisions but random connections" to be computed for specific nodes. > > > thank you for your help and the great piece of software you are developing! > > Beste regards, > stephan > > > _______________________________________________ > igraph-help mailing list > [email protected] > https://lists.nongnu.org/mailman/listinfo/igraph-help _______________________________________________ igraph-help mailing list [email protected] https://lists.nongnu.org/mailman/listinfo/igraph-help
