@inproceedings {INPROC-2008-80, author = {Viktor Avrutin and Michael Schanz}, title = {{Crises cascades within robust chaos in piecewise-smooth maps}}, booktitle = {Proceedings of the 6th EUROMECH Nonlinear Dynamics Conference}, publisher = {European Mechanics Society}, institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany}, pages = {1--6}, type = {Conference Paper}, month = {July}, year = {2008}, keywords = {crises bifurcations; multi-band chaotic attractors; bandcount adding scenario}, language = {English}, cr-category = {J.2 Physical Sciences and Engineering}, contact = {Michael.Schanz@informatik.uni-stuttgart.de Viktor.Avrutin@informatik.uni-stuttgart.de}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Image Understanding}, abstract = {This article describes a novel bifurcation phenomenon occurring in the 2D parameter space of piecewise-linear maps. In the region of chaotic behavior we detect an infinite number of interior crises bounding the regions of multi-band attractors. This phenomenon, denoted as bandcount adding scenario, leads to a self-similar structure of the chaotic region in the parameter space.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-80&engl=1} } @inproceedings {INPROC-2008-53, author = {Uwe-Philipp K{\"a}ppeler and Ruben Benkmann and Oliver Zweigle and Reinhard Lafrenz and Paul Levi}, title = {{Resolving Inconsistencies in Shared Context Models using Multiagent Systems}}, booktitle = {Proceedings of the 10th International Conference on Intelligent Autonomous Systems: IAS-10; Baden Baden, Germany, July 23-25, 2008}, editor = {R{\"u}diger Dillmann and Wolfram Burgard}, address = {Baden Baden}, publisher = {Springer-Verlag}, institution = {University of Stuttgart : Collaborative Research Center SFB 627 (Nexus: World Models for Mobile Context-Based Systems), Germany}, pages = {93--98}, type = {Conference Paper}, month = {July}, year = {2008}, isbn = {978-972-96895-3-6}, keywords = {sensor; fusion; normalized weighted arithmetic mean; inconsistency}, language = {German}, cr-category = {I.2.9 Robotics, H.3 Information Storage and Retrieval}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Image Understanding}, abstract = {The study reported in this paper evaluates procedures that combine a multitude of measurements to a single result that can be integrated in the shared context model. The statistically optimized procedure based on ratings of the participating agents is enhanced using scaled weighted arithmetic means which prevents the system from running into singularities caused by the feedback from the ratings. The method is combined with an additional preprocessing based on fuzzy clustering that detects aberrant measurements which can be excluded from further processing.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-53&engl=1} } @inproceedings {INPROC-2008-45, author = {Ralf Regele}, title = {{Using Ontology-based Traffic Models for more efficient Decision Making of Autonomous Vehicles}}, booktitle = {Proceedings of the 4th International Conference on Autonomic and Autonomous Systems: ICAS '08; Gosier, Guadeloupe, 16-21 March 2008}, editor = {Dominic Greenwood and Michael Grottke and Hanan Lutfiyya and Manuela Popescu}, address = {Gosier}, publisher = {IEEE computer society}, institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany}, pages = {94--99}, type = {Conference Paper}, month = {March}, year = {2008}, isbn = {0-7695-3093-1}, doi = {10.1109/ICAS.2008.10}, keywords = {Autonomous driving; traffic models; traffic coordination; decision making}, language = {English}, cr-category = {A.0 General Literature, General}, contact = {Ralf Regele regele@ipvs.uni-stuttgart.de}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Image Understanding}, abstract = {The paper describes how a high-level abstract world model can be used to support the decision-making process of an autonomous driving system. The approach uses a hierarchical world model and distinguishes between a low-level model for the trajectory planning and a high-level model for solving the traffic coordination problem. The abstract world model used in the CyberCars-2 project is presented. It is based on a topological lane segmentation and introduces relations to represent the semantic context of the traffic scenario. This makes it much easier to realize a consistent and complete driving control system, and to analyze, evaluate and simulate such a system.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-45&engl=1} } @inproceedings {INPROC-2008-23, author = {Ruben Benkmann and Uwe-Philipp K{\"a}ppeler and Oliver Zweigle and Reinhard Lafrenz and Paul Levi}, title = {{Resolving Inconsistencies using Multi-agent Sensor Systems}}, booktitle = {Proceedings of the 8th Conference on Autonomous Robot Systems and Competition: Robotica 08; Aveiro, Portugal, April 2nd, 2008}, editor = {Luis Seabra Lopez and Filipe Silva and Vitor Santos}, address = {Aveiro}, publisher = {Universidade de Aveiro}, institution = {University of Stuttgart : Collaborative Research Center SFB 627 (Nexus: World Models for Mobile Context-Based Systems), Germany}, pages = {93--98}, type = {Conference Paper}, month = {April}, year = {2008}, isbn = {978-972-96895-3-6}, keywords = {Sensor; Fusion; Normalized Weighted Arithmetic Mean}, language = {German}, cr-category = {I.2.9 Robotics, H.3 Information Storage and Retrieval}, contact = {kaeppeler@ipvs.uni-stuttgart.de}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Image Understanding}, abstract = {Agents acting in physical space use perception in combination with their own world models and shared context models to orient. The shared context models have to be adapted permanently to the conditions of the real world. If a measurement of an agent{\^a}€™s sensor does not fit to the corresponding data in the shared context model the system contains an inconsistency. In this case it is necessary to decide whether the reason for the discrepancy is a change in the real world or a measurement error. If there is a change in the real world the shared context model has to be corrected. A single agent can hardly answer this question using its local world model. This work describes the scenario of a context model that is shared with and updated by many agents that possess one or more sensors. In occurrence of an inconsistency it is possible to call other agents to validate a measurement. The functions to call the other agents are provided by the Nexus platform, a federation of systems that manages users and objects in shared dynamic context models. The study reported in this paper evaluates procedures that combine a multitude of measurements to a single result that can be integrated in the shared context model. The statistically optimized procedure based on ratings of the participating agents is enhanced using scaled weighted arithmetic means which prevents the system from running into singularities caused by the feedback from the ratings. The method is combined with an additional preprocessing based on fuzzy clustering that detects aberrant measurements which can be excluded from further processing.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-23&engl=1} } @inproceedings {INPROC-2008-142, author = {Laura Gardini and Viktor Avrutin and Michael Schanz}, title = {{Connection between bifurcations on the Poincare Equator and the dangerous bifurcations}}, booktitle = {Book of Abstracts: European Conference on Iteration Theory: Yalta, Crimea, Ukraine, September 7-13, 2008}, publisher = {Institute of Mathematics, National Academy of Sciences of Ukraine}, institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany}, pages = {1--1}, type = {Conference Paper}, month = {September}, year = {2008}, keywords = {border collision bifurcation; dangerous bifurcation; Poincare equator}, language = {English}, cr-category = {J.2 Physical Sciences and Engineering, G.2 Discrete Mathematics}, contact = {Michael.Schanz@informatik.uni-stuttgart.de Viktor.Avrutin@informatik.uni-stuttgart.de}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Image Understanding}, abstract = {The object of the present work is to describe some bifurcations occurring in the 2D piecewise linear continuous map in canonical form involving the Poincare Equator (i.e. periodic points at infinity) and its relation to the so called ``dangerous bifurcations'' (following Hassouneh et al. [2004] and Ganguli and Banerjee [2005]). It will be shown that such regions are related not only to stable fixed points and repelling saddle cycles, and a more general definition is proposed. The boundaries of such regions are border collision bifurcations of cycles on the Poincare Equator.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-142&engl=1} } @inproceedings {INPROC-2008-114, author = {Oliver Zweigle and Uwe-Philipp K{\"a}ppeler and Hamid Rajaie and Kai H{\"a}u{\ss}ermann and Reinhard Lafrenz and Andreas Tamke and Frank Schreiber and Markus H{\"o}ferlin and Michael Schanz and Paul Levi}, title = {{CoPS Stuttgart Team Description 2008}}, booktitle = {Proceedings of the RoboCup International Symposium; Suzhou, China, July 14-20, 2008}, address = {Suzhou}, publisher = {RoboCup Organization}, institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany}, pages = {1--8}, type = {Conference Paper}, month = {July}, year = {2008}, keywords = {Robot soccer}, language = {English}, cr-category = {I.2.9 Robotics, I.2.10 Vision and Scene Understanding, I.2.11 Distributed Artificial Intelligence, I.2 Artificial Intelligence}, ee = {http://robocup.informatik.uni-stuttgart.de/, www.robocup.org}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Image Understanding}, abstract = {The CoPS robot soccer team is used as a testbed for multi-agent software architecture principles in dynamic real time domains. The current research activities focus on a new controlling architecture, rein- forcement learning for robot behaviors, situation recognition and new vison methots.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-114&engl=1} } @inproceedings {INPROC-2008-104, author = {Reinhard Lafrenz and Michael Schanz and Uwe-Philipp K{\"a}ppeler and Oliver Zweigle and Hamid Rajaie and Frank Schreiber and Paul Levi}, title = {{Evaluating Robustness of Coupled Selection Equations Using Sparse Communication}}, booktitle = {Intelligent Autonomous Systems 10 (IAS-10)}, editor = {Burgard et al.}, publisher = {IOS Press}, institution = {University of Stuttgart, Faculty of Computer Science, Electrical Engineering, and Information Technology, Germany}, pages = {272--277}, type = {Conference Paper}, month = {July}, year = {2008}, language = {English}, cr-category = {I.2.9 Robotics, I.2.11 Distributed Artificial Intelligence, G.1.10 Numerical Analysis Applications}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Image Understanding}, abstract = {In this paper we evaluate the robustness of a self-organized mechanism to distribute roles among a team of cooperating robots. In previous work, we showed the principal applicability of this approach for the RoboCup scenario. Now we test the robustness in case of either intentionally sparse communication or the behavior in situations, where the communication is massively disturbed. To overcome the problems caused by this, each robot runs the equations individually, synchronizing from time to time, or when the communication is available.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=INPROC-2008-104&engl=1} } @article {ART-2008-05, author = {Viktor Avrutin and Bernd Eckstein and Michael Schanz}, title = {{The bandcount increment scenario. II. Interior structures}}, journal = {Proceedings of the Royal Society A}, publisher = {Royal Society Publishing}, volume = {464}, number = {2097}, pages = {2247--2263}, type = {Article in Journal}, month = {September}, year = {2008}, doi = {10.1098/rspa.2007.0299}, keywords = {multi-band chaotic attractors; discontinuous maps; bandcount increment; bandcount adding; bandcount doubling}, language = {English}, cr-category = {G.1.0 Numerical Analysis General, J.2 Physical Sciences and Engineering}, contact = {Michael.Schanz@informatik.uni-stuttgart.de Viktor.Avrutin@informatik.uni-stuttgart.de}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Image Understanding}, abstract = {Bifurcation structures in the two-dimensional parameter spaces formed by chaotic attractors alone are still far away from being understood completely. In a series of three papers, we investigate the chaotic domain without periodic inclusions for a map, which is considered by many authors as some kind of one-dimensional canonical form for discontinuous maps. In this second part, we investigate fine substructures nested into the basic structures reported and explained in part I. It is demonstrated that the overall structure of the chaotic domain is caused by a complex interaction of bandcount increment, bandcount adding and bandcount doubling structures, whereby some of them are nested into each other ad infinitum leading to self-similar structures in the parameter space.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2008-05&engl=1} } @article {ART-2008-04, author = {Viktor Avrutin and Bernd Eckstein and Michael Schanz}, title = {{The bandcount increment scenario. I. Basic structures}}, journal = {Proceedings of the Royal Society A}, publisher = {Royal Society Publishing}, volume = {464}, number = {2095}, pages = {1867--1883}, type = {Article in Journal}, month = {July}, year = {2008}, doi = {10.1098/rspa.2007.0226}, keywords = {multi-band chaotic attractors; discontinuous maps; bandcount increment; bandcount adding; bandcount doubling}, language = {English}, cr-category = {G.1.0 Numerical Analysis General, J.2 Physical Sciences and Engineering}, contact = {Michael.Schanz@informatik.uni-stuttgart.de Viktor.Avrutin@informatik.uni-stuttgart.de}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Image Understanding}, abstract = {Bifurcation structures in 2D parameter spaces formed by chaotic attractors only are still far away from being understood completely. In a series of three papers we investigate the chaotic domain without periodic inclusions for a map which is considered by many authors as some kind of 1D canonical form for discontinuous maps. In the first part we report a novel bifurcation scenario formed by crises bifurcations which includes multi-band chaotic attractors with arbitrary high bandcounts and which determines the basic structure of the chaotic domain.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2008-04&engl=1} } @article {ART-2008-02, author = {Viktor Avrutin and Michael Schanz}, title = {{On the fully developed bandcount adding scenario}}, journal = {Nonlinearity}, publisher = {IOP Publishing}, volume = {21}, pages = {1077--1103}, type = {Article in Journal}, month = {April}, year = {2008}, doi = {10.1088/0951-7715/21/5/010}, keywords = {robust chaos, bandcount adding, crises bifurcations, piecewise linear discontinuous maps}, language = {English}, cr-category = {J.2 Physical Sciences and Engineering}, contact = {Michael.Schanz@informatik.uni-stuttgart.de Viktor.Avrutin@informatik.uni-stuttgart.de}, department = {University of Stuttgart, Institute of Parallel and Distributed Systems, Image Understanding}, abstract = {In this paper we report a new bifurcation phenomenon induced by interior crises, which explains the structure of multi-band chaotic attractors in the case of a piecewise-linear discontinuous map. This phenomenon, denoted as a fully developed bandcount adding scenario, leads to a self-similar structure of the chaotic region in parameter space.}, url = {http://www2.informatik.uni-stuttgart.de/cgi-bin/NCSTRL/NCSTRL_view.pl?id=ART-2008-02&engl=1} }