Berlin 2008 – scientific programme

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DY: Fachverband Dynamik und Statistische Physik

DY 3: Statistical physics of complex networks I

DY 3.5: Talk

Monday, February 25, 2008, 11:30–11:45, A 053

Long-term Evolution of Boolean Network Populations — •Tamara Mihaljev and Barbara Drossel — Institut für Festkörperphysik, Technische Universität Darmstadt, Hochschulstraße 6, 64289 Darmstadt

We investigate the evolution of populations of Random Boolean Networks under the influence of a selection pressure for higher robustness (i.e., a higher probability to return to the same attractor after perturbing one node), and of random mutations (addition and deletion of links, change of update functions). We find that already after a short time the populations reach a state of high fitness. When the population is evolved for much longer times, the mean fitness decreases slowly, and so does the proportion of networks with highest fitness, although the selection pressure remains the same. We ascribe such long-term changes to the fact that even after reaching a state of high fitness evolution slowly drives the populations into regions of network space that are far away from those reached first.