Overview
colloquia - [ 19.09.2005 (11.00) ]
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„Dynamics of production, supply and traffic networks: From the slower-is-faster effect to signal control and business cycles”
Speaker: Prof. Dr. Dirk Helbing, Managing Director Institute for Transport & Economics, University of Tech-nology Dresden.
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Abstract (by author):
Network theory is rapidly changing our understanding of complex
systems, but the relevance of topological features for the dynamic
behavior of production systems, information networks, or cascade
failures of power grids remains to be explored. Based on a simple
model of supply networks, we offer an interpretation of instabilities
and oscillations observed in biological, ecological, economic, and
engineering systems.
We find that most supply networks display damped oscillations, even
when their units - and linear chains of these units - behave in a
non oscillatory way. Moreover, networks of damped oscillators tend to
produce growing oscillations. This surprising behavior offers, for
example, a new interpretation of business cycles and of oscillating
processes. The network structure of material flows itself turns out to
be a source of instability, and cyclical variations are an inherent
feature of decentralized adjustments.
The stability and dynamic behavior of supply networks is investigated
for different topologies, including sequential supply chains, "supply
circles", "supply ladders", and "supply hierarchies". The empirically
observed bullwhip effect in supply chains is explained as a form of
convective instability based on resonance effects and compared to
stop and go traffic. An application of this theory to the optimization
of production networks has large optimization potentials.
We also present a queuing network model for the simulation of urban
traffic networks with street sections of different lengths and
capacities. Based on our autonomous, decentralized control principle,
green waves emerge through synchronization of neighboring traffic
lights. Our new adaptive signal control strategy is expected to
considerably improve throughputs and travel times, using
self-organization principles based on local interactions between
vehicles and traffic lights. Similar adaptive control principles can be
applied to other dynamic queuing networks such as production systems.
gez. Prof. Dr.-Ing. Andreas Reuter
Wir bitten – bei Zusage - um Ihre Antwort an:
E-Mail: Baerbel.Mack (at) eml-r.villa-bosch.de
Tel.: 06221 - 533 201
Fax.: 06221 - 533 298
Bibliographisches zu dem Referenten/Referentin finden Sie unter: www.helbing.org
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Location:
The Carl-Bosch-Auditorium is located in the "Studio" annex of Villa Bosch, 69118 Heidelberg, Schloss-Wolfsbrunnenweg 33; The Studio entrance is ca. 100 m after the entrance to Villa Bosch on the left hand side of the street [www.studio.villa-bosch.de].
Parking:
There is a garage "Unter der Boschwiese" that can be used free of charge. Its entrance is right across the street of Villa Bosch towards the hillside.
Contact:
Bärbel Mack
EML Research gGmbH
Schloss-Wolfsbrunnenweg 33
69118 Heidelberg
Phone: +49 (0)6221 - 533 - 201
Fax: +49 (0)6221 - 533 - 298
Email: [email protected]
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