Berlin 2005 – wissenschaftliches Programm

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SYBN: Biological and Social Networks

SYBN 3: Biologische und Soziale Netzwerke, Postersitzung

SYBN 3.30: Poster

Montag, 7. März 2005, 14:00–15:30, Poster TU E

Self-organized Critical Control — •Klaus Pawelzik and Christian Eurich — Universität Bremen, Institut für Theoretische Physik, Otto-Hahn-Allee 1, 28359 Bremen

In complex systems the distributions of global variables often obey power laws. These robust phenomena have been explained by self-organized criticality (SOC) of spatially extended systems which self-tune to critical points. Here we show that SOC may also arise in low-dimensional balance problems. We investigated the dynamics of feedback systems in which an intrinsically unstable sub-system becomes stabilized by a control system that employs optimal parameter estimation based on recent observations. We observe clear power-law fluctuations with exponents that depend only weakly on system parameters. This novel form of SOC generically emerges in control systems if controllers are very sensitive and have finite memory. Our mechanism might explain the movement statistics observed in human sensorimotor control systems and we suggest that also the power-law fluctuations of stock markets might originate from self-organized critical control.