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AKSOE: Physik sozio-ökonomischer Systeme

AKSOE 10: Poster Session (posters are expected to be displayed the full day 8:30-18:00)

AKSOE 10.69: Poster

Mittwoch, 29. März 2006, 16:00–18:00, P2

Reactions to extreme events: moving threshold model — •Eduardo G. Altmann, Sarah Hallerberg, and Holger Kantz — Max Planck Institute for the Physics of Complex System, Dresden - Germany

The occurrence of unexpected large events is a common feature of complex dynamical systems considered in physical (earthquakes, extreme weather conditions), biological (heart attacks, epileptic seizures), and sociological (stock market crashes) contexts. The harmful effects of such extreme events are due to the overcome of the preventive barriers, what results not only from its extreme character, i.e., large fluctuation of some scientifically relevant observable, but also from its unpredictable nature. An event is thus defined to be extreme if it exceeds a given threshold that corresponds to the preventive barriers, which account for the expected events and typically change in time. These barriers usually increase drastically right after the occurrence of extreme events, but steadily decay in their absence. We consider in this presentation a simple model that mimics the evolution of the protection barriers to study the efficiency of the system’s reaction to extreme events and how it changes our perception of the sequence of extreme events itself. We obtain that the usual method of fighting extreme events introduces a periodicity in their occurrence and is generally less efficient than the use of a constant barrier. On the other hand, it shows a good adaptation to the presence of slow non-stationarities.

[1] E. G. Altmann, S. Hallerberg, H. Kantz, arXiv: physics/0508170, Physica A.