Archive for the ‘Scale-Free’ Category

Uncovering disassortativity in large scale-free networks

Friday, June 22nd, 2012

Uncovering disassortativity in large scale-free networks by Nelly Litvak and Remco van der Hofstad.

Abstract:

Mixing patterns in large self-organizing networks, such as the Internet, the World Wide Web, social and biological networks are often characterized by degree-degree {dependencies} between neighbouring nodes. In this paper we propose a new way of measuring degree-degree {dependencies}. We show that the commonly used assortativity coefficient significantly underestimates the magnitude of {dependencies}, especially in large disassortative networks. We mathematically explain this phenomenon and validate the results on synthetic graphs and real-world network data. As an alternative, we suggest to use rank correlation measures such as the well-known Spearman’s rho. Our experiments convincingly show that Spearman’s rho produces consistent values in graphs of different sizes but similar structure, and it is able to reveal strong (positive or negative) {dependencies} in large graphs. In particular, using the Spearman’s rho we show that preferential attachment model exhibits significant negative degree-degree {dependencies}. We also discover much stronger negative {degree-degree dependencies} in Web graphs than was previously thought. We conclude that rank correlations provide a suitable and informative method for uncovering network mixing patterns.

If you are using graphs/networks and your analysis relies on dependencies between nodes, this could be of interest.

Graphs that involve large numbers of nodes in terrorism analysis, for example.

Being mindful that one person’s “terrorist” is another person’s defender of the homeland.