Dynamics and evolution of biological and social networks

Structural efficiency of percolation landscapes in flow networks

Author: M. Angeles Serrano, Institute of Theoretical Physics, EPFL.

Names and affiliation of other authors:
Paolo De Los Rios
Institute of Theoretical Physics, LBS, SB, EPFL, 1015 Lausanne, Switzerland

Oral presentation

Abstract:
The large-scale structure of complex systems is intimately related to their functionality and evolution. In particular, global transport processes associated to complex networks rely on the presence of directed paths from input to output nodes and edges, which organize in network-spanning linked components. However, the precise relation between such structures and functional or evolutionary aspects remains to be understood. Here, we define quantitatively the structural efficiency of these percolation landscapes in relation to global transport and discuss the key role of edges in the interfaces between core and peripheral components. Furthermore, we assess that optimal topologies should look like "hairy balls" so to minimize bottleneck effects and the sensitivity to failures. Our results on two real networks shaped by very different dynamics and time-scales, the Internet customer-provider set of relationships and the nervous system of the worm Caenorhabditis elegans, suggest that whereas biological evolution has selected a structure close to the optimal layout, competition does not necessarily tend toward the most efficient global architecture.

Dynamics and evolution of biological and social networks. February 18-20th, 2008. Mallorca, Spain.