TY - CHAP A1 - Müller, Tim M. A1 - Schmitt, Andreas A1 - Leise, Philipp A1 - Meck, Tobias A1 - Altherr, Lena A1 - Pelz, Peter F. A1 - Pfetsch, Marc E. T1 - Validation of an optimized resilient water supply system T2 - Uncertainty in Mechanical Engineering N2 - Component failures within water supply systems can lead to significant performance losses. One way to address these losses is the explicit anticipation of failures within the design process. We consider a water supply system for high-rise buildings, where pump failures are the most likely failure scenarios. We explicitly consider these failures within an early design stage which leads to a more resilient system, i.e., a system which is able to operate under a predefined number of arbitrary pump failures. We use a mathematical optimization approach to compute such a resilient design. This is based on a multi-stage model for topology optimization, which can be described by a system of nonlinear inequalities and integrality constraints. Such a model has to be both computationally tractable and to represent the real-world system accurately. We therefore validate the algorithmic solutions using experiments on a scaled test rig for high-rise buildings. The test rig allows for an arbitrary connection of pumps to reproduce scaled versions of booster station designs for high-rise buildings. We experimentally verify the applicability of the presented optimization model and that the proposed resilience properties are also fulfilled in real systems. KW - Optimization KW - Mixed-integer nonlinear programming KW - Water distribution system KW - Resilience KW - Validation Y1 - 2021 SN - 978-3-030-77255-0 SN - 978-3-030-77256-7 U6 - https://doi.org/10.1007/978-3-030-77256-7_7 N1 - Proceedings of the 4th International Conference on Uncertainty in Mechanical Engineering (ICUME 2021), June 7–8, 2021 SP - 70 EP - 80 PB - Springer CY - Cham ER - TY - CHAP A1 - Leise, Philipp A1 - Altherr, Lena A1 - Simon, Nicolai A1 - Pelz, Peter F. T1 - Finding global-optimal gearbox designs for battery electric vehicles T2 - Optimization of complex systems - theory, models, algorithms and applications : WCGO 2019 N2 - In order to maximize the possible travel distance of battery electric vehicles with one battery charge, it is mandatory to adjust all components of the powertrain carefully to each other. While current vehicle designs mostly simplify the powertrain rigorously and use an electric motor in combination with a gearbox with only one fixed transmission ratio, the use of multi-gear systems has great potential. First, a multi-speed system is able to improve the overall energy efficiency. Secondly, it is able to reduce the maximum momentum and therefore to reduce the maximum current provided by the traction battery, which results in a longer battery lifetime. In this paper, we present a systematic way to generate multi-gear gearbox designs that—combined with a certain electric motor—lead to the most efficient fulfillment of predefined load scenarios and are at the same time robust to uncertainties in the load. Therefore, we model the electric motor and the gearbox within a Mixed-Integer Nonlinear Program, and optimize the efficiency of the mechanical parts of the powertrain. By combining this mathematical optimization program with an unsupervised machine learning algorithm, we are able to derive global-optimal gearbox designs for practically relevant momentum and speed requirements. KW - Powertrain KW - Gearbox KW - Optimization KW - BEV KW - WLTP Y1 - 2019 SN - 978-3-030-21802-7 U6 - https://doi.org/10.1007/978-3-030-21803-4_91 SP - 916 EP - 925 PB - Springer CY - Cham ER - TY - CHAP A1 - Stenger, David A1 - Altherr, Lena A1 - Abel, Dirk T1 - Machine learning and metaheuristics for black-box optimization of product families: a case-study investigating solution quality vs. computational overhead T2 - Operations Research Proceedings 2018 N2 - In product development, numerous design decisions have to be made. Multi-domain virtual prototyping provides a variety of tools to assess technical feasibility of design options, however often requires substantial computational effort for just a single evaluation. A special challenge is therefore the optimal design of product families, which consist of a group of products derived from a common platform. Finding an optimal platform configuration (stating what is shared and what is individually designed for each product) and an optimal design of all products simultaneously leads to a mixed-integer nonlinear black-box optimization model. We present an optimization approach based on metamodels and a metaheuristic. To increase computational efficiency and solution quality, we compare different types of Gaussian process regression metamodels adapted from the domain of machine learning, and combine them with a genetic algorithm. We illustrate our approach on the example of a product family of electrical drives, and investigate the trade-off between solution quality and computational overhead. KW - Product family optimization KW - Mixed-integer nonlinear black-box optimization KW - Engineering optimization KW - Machine learning Y1 - 2019 SN - 978-3-030-18499-5 (Print) SN - 978-3-030-18500-8 (Online) U6 - https://doi.org/10.1007/978-3-030-18500-8_47 SP - 379 EP - 385 PB - Springer CY - Cham ER - TY - JOUR A1 - Olbertz, Klaus T1 - Arbeitsrechtliche Akzente der Gesetzgebung und Rechtsprechung in 2018 : Ein kurzweiliger Rückblick auf das Arbeitsrecht des vergangenen Jahres JF - NWB - Steuer- und Wirtschaftsrecht Y1 - 2019 SN - 0028-3460 IS - 5 SP - 266 EP - 279 ER - TY - JOUR A1 - Olbertz, Klaus T1 - Auslandsentsendungen im arbeitsrechtlichen Zusammenhang : Ausgestaltung eines Entsendungsvertrags und mitbestimmungsrechtliche Aspekte JF - NWB - Steuer- und Wirtschaftsrecht Y1 - 2019 SN - 0028-3460 IS - 19 SP - 1400 EP - 1406 ER - TY - JOUR A1 - Olbertz, Klaus T1 - Rechtssichere Vereinbarungen von Kündigungsfristen im Arbeitsvertrag : Weitestgehende Abdingbarkeit gesetzlicher Vorgaben ermöglicht passgenaue Gestaltungen JF - NWB - Steuer- und Wirtschaftsrecht Y1 - 2019 SN - 0028-3460 IS - 23 SP - 1693 EP - 1699 ER - TY - JOUR A1 - Olbertz, Klaus T1 - Die Optionen des Arbeitgebers nach Krankmeldung des Arbeitnehmers : Ein Überblick über die Rechte und Pflichten des Arbeitgebers bei Arbeitsunfähigkeit des Mitarbeiters JF - NWB - Steuer- und Wirtschaftsrecht Y1 - 2019 SN - 0028-3460 IS - 30 SP - 2222 EP - 2229 ER - TY - JOUR A1 - Olbertz, Klaus T1 - Die arbeitsvertragliche Vereinbarung von Vertragsstrafen : Anforderungen an wirksame Vertragsstrafenabreden in Formulararbeitsverträgen beachten JF - NWB - Steuer- und Wirtschaftsrecht Y1 - 2019 SN - 0028-3460 IS - 45 SP - 3302 EP - 3308 ER - TY - JOUR A1 - Olbertz, Klaus T1 - Jahresrückblick Arbeitsrecht 2019 : Gesetzesänderungen und insbesondere im Zeichen des Befristungs- und Urlaubsrechts stehende höchstrichterliche Rechtsprechung JF - NWB - Steuer- und Wirtschaftsrecht N2 - In Fortschreibung des Jahresrückblicks 2018 (Olbertz, NWB 5/2019 S. 266 ) skizziert der vorliegende Beitrag die jüngsten nennenswerten Entwicklungen im Arbeitsrecht des Jahres 2019. Im Bereich der Gesetzgebung, mit dem sich der erste Teil des Beitrags befasst, betrifft dies etwa das Fachkräfteeinwanderungsgesetz, die angestoßenen Schutzvorschriften für Whistleblower oder das gesetzlich verankerte Recht auf Brückenteilzeit. In der arbeitsrechtlichen höchstrichterlichen Rechtsprechung stand das Jahr 2019 insbesondere im Zeichen des Befristungs- und des Urlaubsrechts. Was hier und darüber hinaus wegweisend war, zeigt der zweite Teil des Beitrags. Y1 - 2020 SN - 0028-3460 IS - 8 SP - 557 EP - 569 PB - NWB-Verl. CY - Herne ER - TY - JOUR A1 - Olbertz, Klaus T1 - GmbH-Geschäftsführer: das eine Mal Arbeitnehmer, das andere Mal nicht : Arbeits- und sozialrechtliche Anwendung von Schutzvorschriften auf den Geschäftsführer von A bis Z JF - NWB - Steuer- und Wirtschaftsrecht Y1 - 2020 SN - 0028-3460 IS - 19 SP - 1431 EP - 1441 PB - NWB-Verl. CY - Herne ER -