Dr Marc Barthelemy, Commissariat à L’Energie Atomique – Département de Physique
Abstract: Many complex systems, including networks, are not static but can display strong fluctuations at various time scales. Characterizing the dynamics in complex networks is thus of the utmost importance in the understanding of these networks and of the dynamical processes taking place on them. In this talk, I will present the example of the US airport network in the time period 1990-2000. I will show that even if the statistical distributions of most indicators are stationary, an intense activity takes place at the local ('microscopic') level, with many disappearing/appearing connections (links) between airports, and a very broad distribution of lifetimes.
In particular, the links which disappear have essentially the same properties as the ones which appear, and links which connect airports with very different traffic are very volatile. In a last part, I will propose a model for dynamical networks, inspired by previous studies on firm growth, and which reproduces most of the empirical observations on the US airport network both for the stationary statistical distributions and for the dynamical properties.