@inproceedings{LimpertSchifferFerrein2015, author = {Limpert, Nicolas and Schiffer, Stefan and Ferrein, Alexander}, title = {A Local Planner for Ackermann-Driven Vehicles in ROS SBPL}, series = {Proceedings of the International Conference on Pattern Recognition Association of South Africa and Robotics and Mechatronics (PRASA-RobMech), 2015}, booktitle = {Proceedings of the International Conference on Pattern Recognition Association of South Africa and Robotics and Mechatronics (PRASA-RobMech), 2015}, doi = {10.1109/RoboMech.2015.7359518}, pages = {172 -- 177}, year = {2015}, language = {en} } @techreport{LessenichRitzWallenborn2014, author = {Leßenich, Nina and Ritz, Thomas and Wallenborn, Ramona}, title = {Prototyping zur Verbesserung der Benutzerfreundlichkeit mobiler Software : Potenziale benutzerfreundlicher Software-Entwicklung ; Info-Brosch{\"u}re}, publisher = {eBusiness-Lotse}, address = {Aachen}, pages = {7 S. : Ill., graph. Darst.}, year = {2014}, abstract = {Mobile Anwendungen nehmen mit der Verbreitung von Smartphones zu. Die Akzeptanz der Nutzer bestimmt den Erfolg solcher mobiler Applikationen dabei maßgeblich. Um diese Anerkennung zu schaffen, ist eine m{\"o}glichst hohe Gebrauchstauglichkeit, auch Usability genannt, notwendig. Die Informationsbrosch{\"u}re „Prototyping zur Verbesserung der Benutzerfreundlichkeit mobiler Software" richtet sich an Personen, die an der Gestaltung und entwicklung von (mobiler) Software beteiligt sind. In dieser Brosch{\"u}re werden m{\"o}gliche Potenziale im Bereich einer effizienten und benutzerzentrierten Software-Entwicklung aufgezeigt.}, language = {de} } @article{LerchlKruegerNiehausetal.2008, author = {Lerchl, Alexander and Kr{\"u}ger, Heike and Niehaus, Michael and Streckert, Joachim R. and Bitz, Andreas and Hansen, Volkert}, title = {Effects of mobile phone electromagnetic fields at nonthermal SAR values on melatonin and body weight of Djungarian hamsters (Phodopus sungorus)}, series = {Journal of Pineal Research}, volume = {44}, journal = {Journal of Pineal Research}, number = {3}, issn = {1600-079X}, doi = {10.1111/j.1600-079X.2007.00522.x}, pages = {267 -- 272}, year = {2008}, language = {en} } @article{LepersRakePuetter1976, author = {Lepers, Heinrich and Rake, H. and P{\"u}tter, L.}, title = {Regelung der Qualitaet beim Brennen von Zementklinker}, series = {Regelungstechnische Praxis : rtp}, volume = {18}, journal = {Regelungstechnische Praxis : rtp}, number = {4}, publisher = {Oldenbourg}, address = {M{\"u}nchen}, issn = {0340-4730}, pages = {87 -- 91}, year = {1976}, language = {de} } @article{LepersRakePuetter1976, author = {Lepers, Heinrich and Rake, H. and P{\"u}tter, L.}, title = {Prozeßrechnerautomatisierung von W{\"a}rmeprozessen in der Grundstoffindustrie}, series = {Industrie-Anzeiger}, volume = {98}, journal = {Industrie-Anzeiger}, number = {17/18}, publisher = {Konradin}, address = {Leinfelden-Echterdingen}, issn = {0019-9036}, pages = {286 -- 289}, year = {1976}, language = {de} } @article{LepersRakePuetter1976, author = {Lepers, Heinrich and Rake, H. and P{\"u}tter, L.}, title = {Prozeßrechnerautomatisierung von W{\"a}rmeprozessen}, series = {Elektro-Anzeiger}, volume = {29}, journal = {Elektro-Anzeiger}, number = {5}, publisher = {Konradin}, address = {Leinfelden-Echterdingen}, issn = {0013-5518}, pages = {98 -- 101}, year = {1976}, language = {de} } @article{LepersJaegerPuetter1977, author = {Lepers, Heinrich and J{\"a}ger, G. and P{\"u}tter, L.}, title = {Anwendung eines Prozessmodells zur Regelung der Produktqualit{\"a}t bei der Zementklinker-Herstellung / Jaeger, G. ; Lepers, H. Puetter, L. [u.a.]}, series = {VDI-Berichte (1977)}, journal = {VDI-Berichte (1977)}, pages = {87 -- 93}, year = {1977}, language = {de} } @book{Lepers2005, author = {Lepers, Heinrich}, title = {SPS-Programmierung nach IEC 61131-3: mit Beispielen CoDeSys und STEP 7 ; [auf 3 CD-ROMs Installationssoftware f{\"u}r CoDeSys und STEP 7 mit CFC, alle Beispiele aus dem Buch f{\"u}r CoDeSys und STEP 7, alle L{\"o}sungen zu den {\"U}bungsprojekten f{\"u}r CoDeSys und STEP 7]}, publisher = {Franzis}, address = {Poing}, isbn = {3-7723-5801-2}, pages = {350 S.; Ill., graph. Darst.}, year = {2005}, language = {de} } @article{Lepers1972, author = {Lepers, Heinrich}, title = {Integrationsverfahren zur Systemidentifizierung aus gemessenen Systemantworten}, series = {Regelungstechnik}, volume = {20}, journal = {Regelungstechnik}, number = {10}, publisher = {Oldenbourg}, address = {M{\"u}nchen}, doi = {10.1524/auto.1972.20.112.417}, pages = {417 -- 422}, year = {1972}, abstract = {F{\"u}r viele Zwecke ist es n{\"u}tzlich, von einem technischen System ein mathematisches Modell zu haben. F{\"u}r Systeme, die sich durch eine Verz{\"o}gerung h{\"o}herer Ordnung mit oder ohne Ausgleich beschreiben lassen, wird ein Identifizierungsverfahren vorgestellt, das aus gemessenen Zeitfunktionen die Bestimmung einer {\"U}bertragungsfunktion erm{\"o}glicht. Die Systeme werden dabei durch Testsignale erregt. Die Modellkoeffizienten werden dann mit Hilfe eines Integrationsverfahrens aus dem Testsignal und der Antwort des Systems auf dieses Testsignal bestimmt. Ein praktisches Beispiel zeigt die Leistungsf{\"a}higkeit des Verfahrens.}, language = {de} } @article{Lepers1973, author = {Lepers, Heinrich}, title = {Fehler bei der Systemanalyse aus stochastisch gest{\"o}rten Sprungantworten}, series = {Regelungstechnik und Prozeß-Datenverarbeitung}, volume = {21}, journal = {Regelungstechnik und Prozeß-Datenverarbeitung}, number = {7}, publisher = {De Gruyter}, address = {Berlin}, issn = {0034-3226}, doi = {10.1524/auto.1973.21.112.229}, pages = {229 -- 233}, year = {1973}, abstract = {Es wird von Gleichungen ausgegangen, mit denen die Modellkoeffizienten von Regelstrecken mit Ausgleich aus der gemessenen Sprungantwort ermittelt werden k{\"o}nnen. Die {\"U}bertragungsfunktion der Regelstrecke hat einen konstanten Z{\"a}hler und ein Nennerpolynom. Unter der Annahme, daß die ideale und exakte Sprungantwort des Systems durch ein stochastisches Signal gest{\"o}rt wird, wird untersucht, wie die Fehler der ermittelten Modellkoeffizienten von Kennwerten des St{\"o}rsignals und von der Meßzeit f{\"u}r die Sprungantwort abh{\"a}ngen. Durch eine Simulation auf dem Digitalrechner wurden die Ergebnisse kontrolliert. Es zeigt sich, daß durch eine Filterung der gest{\"o}rten Sprungantwort {\"u}ber einen Tiefpaß keine Verbesserung der Analyseergebnisse erreicht werden kann, da das Identifizierungsverfahren eine gl{\"a}ttende Eigenschaft hat.}, language = {de} } @article{Lepers1972, author = {Lepers, Heinrich}, title = {Empfindlichkeitsuntersuchungen zur Beurteilung von Optimierungen mit fehlerhaften Modellen}, series = {Messen, Steuern, Regeln}, volume = {15}, journal = {Messen, Steuern, Regeln}, number = {11}, publisher = {Oldenbourg}, address = {M{\"u}nchen}, issn = {0026-0347}, pages = {407 -- 410}, year = {1972}, language = {de} } @book{Lepers1971, author = {Lepers, Heinrich}, title = {Identifizierung von stochastisch gest{\"o}rten Regelstrecken mit aperiodischen Testsignalen}, pages = {115 S.}, year = {1971}, language = {de} } @book{Lepers2007, author = {Lepers, Heinrich}, title = {SPS-Programmierung nach IEC 61131-3 : mit Beispielen f{\"u}r CoDeSys und STEP 7 / 2. Aufl.}, publisher = {Franzis}, address = {Poing}, isbn = {978-3-7723-5805-0}, pages = {350 S. : Ill., graph. Darst. + 3 CD-ROMs}, year = {2007}, language = {de} } @book{Lepers2009, author = {Lepers, Heinrich}, title = {SPS-Programmierung nach IEC 61131-3 : mit Beispielen f{\"u}r CoDeSys und STEP 7 ; [auf 4 DVDs/CDs: Installationssoftware f{\"u}r CoDeSys, STEP 7 und WINCC flexible ; alle Beispiele aus dem Buch f{\"u}r CoDeSys und STEP7 ; alle L{\"o}sungen zu den {\"U}bungsprojekten f{\"u}r CoDeSys und STEP 7] / Heinrich Lepers . 3. neu bearb. Aufl.}, publisher = {Franzis}, address = {Poing}, isbn = {978-3-7723-5806-7}, pages = {429 S. : Ill., graph. Darst.}, year = {2009}, language = {de} } @inproceedings{LenzWolf2014, author = {Lenz, Laura L. and Wolf, Martin}, title = {Economic evaluation of serious games with the comparative assessment framework COSEGA}, series = {The shift from teaching to learning : individual, collective and organizational learning through gaming simulation ; proceedings of the 45th conference of the International Simulation and Gaming Association, Dornbirn 2014}, booktitle = {The shift from teaching to learning : individual, collective and organizational learning through gaming simulation ; proceedings of the 45th conference of the International Simulation and Gaming Association, Dornbirn 2014}, editor = {Kritz, Willy Christian}, publisher = {Bertelsmann}, address = {[Bielefeld]}, isbn = {978-3-7639-5422-3}, pages = {374 -- 386}, year = {2014}, language = {en} } @inproceedings{LeiseSimonAltherr2020, author = {Leise, Philipp and Simon, Nicolai and Altherr, Lena}, title = {Comparison of Piecewise Linearization Techniques to Model Electric Motor Efficiency Maps: A Computational Study}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48439-2}, doi = {10.1007/978-3-030-48439-2_55}, pages = {457 -- 463}, year = {2020}, abstract = {To maximize the travel distances of battery electric vehicles such as cars or buses for a given amount of stored energy, their powertrains are optimized energetically. One key part within optimization models for electric powertrains is the efficiency map of the electric motor. The underlying function is usually highly nonlinear and nonconvex and leads to major challenges within a global optimization process. To enable faster solution times, one possibility is the usage of piecewise linearization techniques to approximate the nonlinear efficiency map with linear constraints. Therefore, we evaluate the influence of different piecewise linearization modeling techniques on the overall solution process and compare the solution time and accuracy for methods with and without explicitly used binary variables.}, language = {en} } @article{LeiseEsserEichenlaubetal.2021, author = {Leise, Philipp and Eßer, Arved and Eichenlaub, Tobias and Schleiffer, Jean-Eric and Altherr, Lena and Rinderknecht, Stephan and Pelz, Peter F.}, title = {Sustainable system design of electric powertrains - comparison of optimization methods}, series = {Engineering Optimization}, journal = {Engineering Optimization}, publisher = {Taylor \& Francis}, address = {London}, issn = {0305-215X}, doi = {10.1080/0305215X.2021.1928660}, year = {2021}, abstract = {The transition within transportation towards battery electric vehicles can lead to a more sustainable future. To account for the development goal 'climate action' stated by the United Nations, it is mandatory, within the conceptual design phase, to derive energy-efficient system designs. One barrier is the uncertainty of the driving behaviour within the usage phase. This uncertainty is often addressed by using a stochastic synthesis process to derive representative driving cycles and by using cycle-based optimization. To deal with this uncertainty, a new approach based on a stochastic optimization program is presented. This leads to an optimization model that is solved with an exact solver. It is compared to a system design approach based on driving cycles and a genetic algorithm solver. Both approaches are applied to find efficient electric powertrains with fixed-speed and multi-speed transmissions. Hence, the similarities, differences and respective advantages of each optimization procedure are discussed.}, language = {en} } @inproceedings{LeiseBreuerAltherretal.2020, author = {Leise, Philipp and Breuer, Tim and Altherr, Lena and Pelz, Peter F.}, title = {Development, validation and assessment of a resilient pumping system}, series = {Proceedings of the Joint International Resilience Conference, JIRC2020}, booktitle = {Proceedings of the Joint International Resilience Conference, JIRC2020}, isbn = {978-90-365-5095-6}, pages = {97 -- 100}, year = {2020}, abstract = {The development of resilient technical systems is a challenging task, as the system should adapt automatically to unknown disturbances and component failures. To evaluate different approaches for deriving resilient technical system designs, we developed a modular test rig that is based on a pumping system. On the basis of this example system, we present metrics to quantify resilience and an algorithmic approach to improve resilience. This approach enables the pumping system to automatically react on unknown disturbances and to reduce the impact of component failures. In this case, the system is able to automatically adapt its topology by activating additional valves. This enables the system to still reach a minimum performance, even in case of failures. Furthermore, timedependent disturbances are evaluated continuously, deviations from the original state are automatically detected and anticipated in the future. This allows to reduce the impact of future disturbances and leads to a more resilient system behaviour.}, language = {en} } @incollection{LeiseAltherrSimonetal.2019, author = {Leise, Philipp and Altherr, Lena and Simon, Nicolai and Pelz, Peter F.}, title = {Finding global-optimal gearbox designs for battery electric vehicles}, series = {Optimization of complex systems - theory, models, algorithms and applications : WCGO 2019}, booktitle = {Optimization of complex systems - theory, models, algorithms and applications : WCGO 2019}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-21802-7}, doi = {10.1007/978-3-030-21803-4_91}, pages = {916 -- 925}, year = {2019}, abstract = {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.}, language = {en} } @inproceedings{LeiseAltherrPelz2018, author = {Leise, Philipp and Altherr, Lena and Pelz, Peter F.}, title = {Technical Operations Research (TOR) - Algorithms, not Engineers, Design Optimal Energy Efficient and Resilient Cooling Systems}, series = {FAN2018 - Proceedings of the International Conference on Fan Noise, Aerodynamics, Applications and Systems}, booktitle = {FAN2018 - Proceedings of the International Conference on Fan Noise, Aerodynamics, Applications and Systems}, pages = {1 -- 12}, year = {2018}, abstract = {The overall energy efficiency of ventilation systems can be improved by considering not only single components, but by considering as well the interplay between every part of the system. With the help of the method "TOR" ("Technical Operations Research"), which was developed at the Chair of Fluid Systems at TU Darmstadt, it is possible to improve the energy efficiency of the whole system by considering all possible design choices programmatically. We show the ability of this systematic design approach with a ventilation system for buildings as a use case example. Based on a Mixed-Integer Nonlinear Program (MINLP) we model the ventilation system. We use binary variables to model the selection of different pipe diameters. Multiple fans are model with the help of scaling laws. The whole system is represented by a graph, where the edges represent the pipes and fans and the nodes represents the source of air for cooling and the sinks, that have to be cooled. At the beginning, the human designer chooses a construction kit of different suitable fans and pipes of different diameters and different load cases. These boundary conditions define a variety of different possible system topologies. It is not possible to consider all topologies by hand. With the help of state of the art solvers, on the other side, it is possible to solve this MINLP. Next to this, we also consider the effects of malfunctions in different components. Therefore, we show a first approach to measure the resilience of the shown example use case. Further, we compare the conventional approach with designs that are more resilient. These more resilient designs are derived by extending the before mentioned model with further constraints, that consider explicitly the resilience of the overall system. We show that it is possible to design resilient systems with this method already in the early design stage and compare the energy efficiency and resilience of these different system designs.}, language = {en} }