TY - BOOK A1 - Altherr, Lena T1 - Algorithmic System Design under Consideration of Dynamic Processes N2 - Nach Stand von Wissenschaft und Technik werden Komponenten hinsichtlich ihrer Eigenschaften, wie Lebensdauer oder Energieeffizienz, optimiert. Allerdings können selbst hervorragende Komponenten zu ineffizienten oder instabilen Systemen führen, wenn ihr Zusammenspiel nur unzureichend berücksichtigt wird. Eine Systembetrachtung schafft ein größeres Optimierungspotential - dem erhöhten Potential steht jedoch auch ein erhöhter Komplexitätsgrad gegenüber. Die vorliegende Arbeit ist im Rahmen des Sonderforschungsbereichs 805 entstanden, dessen Ziel die Beherrschung von Unsicherheit in Systemen des Maschinenbaus ist. Die Arbeit zeigt anhand eines realen Systems aus dem Bereich der Hydraulik, wie Unsicherheit in der Entwicklungsphase beherrscht werden kann. Hierbei ist neu, dass die durch den späteren Betrieb zu erwartende Systemdegradation eines jeden möglichen Systemvorschlags antizipiert werden kann. Dadurch können Betriebs- und Wartungskosten vorausgesagt und minimiert werden und durch eine optimale Betriebs- und Wartungsstrategie die Verfügbarkeit des Systems garantiert werden. Wesentliche Fragen bei der optimalen Auslegung des betrachteten hydrostatischen Getriebes sind dessen physikalische Modellierung, die Darstellung des Optimierungsproblems als gemischt-ganzzahliges lineares Programm, und dessen algorithmische Behandlung zur Lösungsfindung. Hierzu werden Heuristiken zum schnelleren Auffinden sinnvoller Systemtopologien vorgestellt und mittels mathematischer Dekomposition eine Bewertung des dynamischen Verschleiß- und Wartungsverlaufs möglicher Systemvorschläge vorgenommen. Die Arbeit stellt die Optimierung technischer Systeme an der Schnittstelle von Mathematik, Informatik und Ingenieurwesen sowohl gründlich als auch anschaulich und nachvollziehbar dar. KW - Mixed Integer Programming KW - Technical Operations Research KW - Optimization KW - System Design Y1 - 2016 SN - 978-3-8440-4848-3 PB - Shaker CY - Aachen ER - TY - CHAP A1 - Neumann, Tobias A1 - Dülberg, Enno A1 - Schiffer, Stefan A1 - Ferrein, Alexander T1 - A rotating platform for swift acquisition of dense 3D point clouds T2 - Intelligent Robotics and Applications: 9th International Conference, ICIRA 2016, Tokyo, Japan, August 22-24, 2016, Proceedings, Part I Y1 - 2016 SN - 978-3-319-43505-3 (Print) SN - 978-3-319-43506-0 (Online) U6 - http://dx.doi.org/10.1007/978-3-319-43506-0_22 N1 - Series: Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) VL - 9834 SP - 257 EP - 268 PB - Springer ER - TY - JOUR A1 - Orzada, Stephan A1 - Ladd, Mark E. A1 - Bitz, Andreas T1 - A method to approximate maximum local SAR in multichannel transmit MR systems without transmit phase information JF - Magnetic Resonance in Medicine N2 - Purpose To calculate local specific absorption rate (SAR) correctly, both the amplitude and phase of the signal in each transmit channel have to be known. In this work, we propose a method to derive a conservative upper bound for the local SAR, with a reasonable safety margin without knowledge of the transmit phases of the channels. Methods The proposed method uses virtual observation points (VOPs). Correction factors are calculated for each set of VOPs that prevent underestimation of local SAR when the VOPs are applied with the correct amplitudes but fixed phases. Results The proposed method proved to be superior to the worst-case calculation based on the maximum eigenvalue of the VOPs. The mean overestimation for six coil setups could be reduced, whereas no underestimation of the maximum local SAR occurred. In the best investigated case, the overestimation could be reduced from a factor of 3.3 to a factor of 1.7. Conclusion The upper bound for the local SAR calculated with the proposed method allows a fast estimation of the local SAR based on power measurements in the transmit channels and facilitates SAR monitoring in systems that do not have the capability to monitor transmit phases Y1 - 2016 U6 - http://dx.doi.org/10.1002/mrm.26398 SN - 1522-2594 VL - 78 IS - 2 SP - 805 EP - 811 PB - International Society for Magnetic Resonance in Medicine ER - TY - CHAP A1 - Rausch, Lea A1 - Leise, Philipp A1 - Ederer, Thorsten A1 - Altherr, Lena A1 - Pelz, Peter F. ED - Papadrakakis, M. ED - Ppadopoulos, V. ED - Stefanou, G. ED - Plevris, V. T1 - A comparison of MILP and MINLP solver performance on the example of a drinking water supply system design problem T2 - ECCOMAS Congress 2016 VII European Congress on Computational Methods in Applied Sciences and Engineering N2 - Finding a good system topology with more than a handful of components is a highly non-trivial task. The system needs to be able to fulfil all expected load cases, but at the same time the components should interact in an energy-efficient way. An example for a system design problem is the layout of the drinking water supply of a residential building. It may be reasonable to choose a design of spatially distributed pumps which are connected by pipes in at least two dimensions. This leads to a large variety of possible system topologies. To solve such problems in a reasonable time frame, the nonlinear technical characteristics must be modelled as simple as possible, while still achieving a sufficiently good representation of reality. The aim of this paper is to compare the speed and reliability of a selection of leading mathematical programming solvers on a set of varying model formulations. This gives us empirical evidence on what combinations of model formulations and solver packages are the means of choice with the current state of the art. KW - Technical Operations Research KW - Mixed-Integer Nonlinear Optimisation KW - Solver Per- formance KW - Drinking Water Supply KW - System Design Problem Y1 - 2016 SN - 978-618-82844-0-1 N1 - ECCOMAS Congress 2016 VII European Congress on Computational Methods in Applied Sciences and Engineering, 5–10 June 2016.Crete Island, Greece SP - 8509 EP - 8527 ER - TY - JOUR A1 - Ferrein, Alexander A1 - Steinbauer, Gerald T1 - 20 Years of RoboCup - A Subjective Retrospection JF - KI - Künstliche Intelligenz N2 - This summer, RoboCup competitions were held for the 20th time in Leipzig, Germany. It was the second time that RoboCup took place in Germany, 10 years after the 2006 RoboCup in Bremen. In this article, we give an overview on the latest developments of RoboCup and what happened in the different leagues over the last decade. With its 20th edition, RoboCup clearly is a success story and a role model for robotics competitions. From our personal view point, we acknowledge this by giving a retrospection about what makes RoboCup such a success. Y1 - 2016 U6 - http://dx.doi.org/10.1007/s13218-016-0449-5 SN - 1610-1987 VL - 30 IS - 3 SP - 225 EP - 232 PB - Springer CY - Berlin ER - TY - JOUR A1 - Steinbauer, Gerald A1 - Ferrein, Alexander T1 - 20 Years of RoboCup JF - KI - Künstliche Intelligenz Y1 - 2016 U6 - http://dx.doi.org/10.1007/s13218-016-0442-z SN - 1610-1987 VL - 30 IS - 3-4 SP - 221 EP - 224 PB - Springer CY - Berlin ER -