TY  - JOUR
A1  - Müller, Tim M.
A1  - Leise, Philipp
A1  - Lorenz, Imke-Sophie
A1  - Altherr, Lena
A1  - Pelz, Peter F.
T1  - Optimization and validation of pumping system design and operation for water supply in high-rise buildings
JF  - Optimization and Engineering
N2  - The application of mathematical optimization methods for water supply system design and operation provides the capacity to increase the energy efficiency and to lower the investment costs considerably. We present a system approach for the optimal design and operation of pumping systems in real-world high-rise buildings that is based on the usage of mixed-integer nonlinear and mixed-integer linear modeling approaches. In addition, we consider different booster station topologies, i.e. parallel and series-parallel central booster stations as well as decentral booster stations. To confirm the validity of the underlying optimization models with real-world system behavior, we additionally present validation results based on experiments conducted on a modularly constructed pumping test rig. Within the models we consider layout and control decisions for different load scenarios, leading to a Deterministic Equivalent of a two-stage stochastic optimization program. We use a piecewise linearization as well as a piecewise relaxation of the pumps’ characteristics to derive mixed-integer linear models. Besides the solution with off-the-shelf solvers, we present a problem specific exact solving algorithm to improve the computation time. Focusing on the efficient exploration of the solution space, we divide the problem into smaller subproblems, which partly can be cut off in the solution process. Furthermore, we discuss the performance and applicability of the solution approaches for real buildings and analyze the technical aspects of the solutions from an engineer’s point of view, keeping in mind the economically important trade-off between investment and operation costs.
KW  - Technical Operations Research
KW  - MINLP
KW  - MILP
KW  - Experimental validation
KW  - Pumping systems
Y1  - 2020
U6  - http://dx.doi.org/10.1007/s11081-020-09553-4
SN  - 1573-2924
VL  - 2021
IS  - 22
SP  - 643
EP  - 686
PB  - Springer
ER  - 
TY  - CHAP
A1  - Lorenz, Imke-Sophie
A1  - Altherr, Lena
A1  - Pelz, Peter F.
ED  - Neufeld, Janis S.
ED  - Buscher, Udo
ED  - Lasch, Rainer
ED  - Möst, Dominik
ED  - Schönberger, Jörn
T1  - Assessing and Optimizing the Resilience of Water Distribution Systems Using Graph-Theoretical Metrics
T2  - Operations Research Proceedings 2019
N2  - Water distribution systems are an essential supply infrastructure for cities. Given that climatic and demographic influences will pose further challenges for these infrastructures in the future, the resilience of water supply systems, i.e. their ability to withstand and recover from disruptions, has recently become a subject of research. To assess the resilience of a WDS, different graph-theoretical approaches exist. Next to general metrics characterizing the network topology, also hydraulic and technical restrictions have to be taken into account. In this work, the resilience of an exemplary water distribution network of a major German city is assessed, and a Mixed-Integer Program is presented which allows to assess the impact of capacity adaptations on its resilience.
KW  - OR 2019
KW  - business analytics
KW  - decision analytics
KW  - digital economy
KW  - mathematical optimization
Y1  - 2020
SN  - 978-3-030-48439-2
SN  - 978-3-030-48438-5
U6  - http://dx.doi.org/10.1007/978-3-030-48439-2_63
N1  - Annual International Conference of the German Operations Research Society (GOR), Dresden, Germany, September 4-6, 2019
SP  - 521
EP  - 527
PB  - Springer
CY  - Cham
ER  - 
TY  - CHAP
A1  - Leise, Philipp
A1  - Simon, Nicolai
A1  - Altherr, Lena
T1  - Comparison of Piecewise Linearization Techniques to Model Electric Motor Efficiency Maps: A Computational Study
T2  - Operations Research Proceedings 2019
N2  - 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.
KW  - MINLP
KW  - Powertrain
KW  - Piecewise linearization
KW  - Efficiency optimization
Y1  - 2020
SN  - 978-3-030-48439-2
SN  - 978-3-030-48438-5
U6  - http://dx.doi.org/10.1007/978-3-030-48439-2_55
N1  - Annual International Conference of the German Operations Research Society (GOR), Dresden, Germany, September 4-6, 2019
SP  - 457
EP  - 463
PB  - Springer
CY  - Cham
ER  - 
TY  - CHAP
A1  - Chajan, Eduard
A1  - Schulte-Tigges, Joschua
A1  - Reke, Michael
A1  - Ferrein, Alexander
A1  - Matheis, Dominik
A1  - Walter, Thomas
T1  - GPU based model-predictive path control for self-driving vehicles
T2  - IEEE Intelligent Vehicles Symposium (IV)
N2  - One central challenge for self-driving cars is a proper path-planning. Once a trajectory has been found, the next challenge is to accurately and safely follow the precalculated path. The model-predictive controller (MPC) is a common approach for the lateral control of autonomous vehicles. The MPC uses a vehicle dynamics model to predict the future states of the vehicle for a given prediction horizon. However, in order to achieve real-time path control, the computational load is usually large, which leads to short prediction horizons. To deal with the computational load, the control algorithm can be parallelized on the graphics processing unit (GPU). In contrast to the widely used stochastic methods, in this paper we propose a deterministic approach based on grid search. Our approach focuses on systematically discovering the search area with different levels of granularity. To achieve this, we split the optimization algorithm into multiple iterations. The best sequence of each iteration is then used as an initial solution to the next iteration. The granularity increases, resulting in smooth and predictable steering angle sequences. We present a novel GPU-based algorithm and show its accuracy and realtime abilities with a number of real-world experiments.
KW  - Heuristic algorithms
KW  - Computational modeling
KW  - model-predictive control
KW  - GPU
KW  - autonomous driving
Y1  - 2021
SN  - 978-1-7281-5394-0
U6  - http://dx.doi.org/10.1109/IV48863.2021.9575619
N1  - 2021 IEEE Intelligent Vehicles Symposium (IV)
July 11-17, 2021. Nagoya, Japan
SP  - 1243
EP  - 1248
PB  - IEEE
ER  - 
TY  - CHAP
A1  - Hüning, Felix
A1  - Wache, Franz-Josef
A1  - Magiera, David
T1  - Redundant bus systems using dual-mode radio
T2  - Proceedings of Sixth International Congress on Information and Communication Technology
N2  - Communication via serial bus systems, like CAN, plays an important role for all kinds of embedded electronic and mechatronic systems. To cope up with the requirements for functional safety of safety-critical applications, there is a need to enhance the safety features of the communication systems. One measure to achieve a more robust communication is to add redundant data transmission path to the applications. In general, the communication of real-time embedded systems like automotive applications is tethered, and the redundant data transmission lines are also tethered, increasing the size of the wiring harness and the weight of the system. A radio link is preferred as a redundant transmission line as it uses a complementary transmission medium compared to the wired solution and in addition reduces wiring harness size and weight. Standard wireless links like Wi-Fi or Bluetooth cannot meet the requirements for real-time capability with regard to bus communication. Using the new dual-mode radio enables a redundant transmission line meeting all requirements with regard to real-time capability, robustness and transparency for the data bus. In addition, it provides a complementary transmission medium with regard to commonly used tethered links. A CAN bus system is used to demonstrate the redundant data transfer via tethered and wireless CAN.
Y1  - 2021
SN  - 978-981-16-2379-0
SN  - 978-981-16-2380-6
U6  - http://dx.doi.org/10.1007/978-981-16-2380-6_73
N1  - Proceedings of Sixth International Congress on Information and Communication Technology, ICICT 2021, Brunel University, London, February 25–26, 2021
SP  - 835
EP  - 842
PB  - Springer
CY  - Singapore
ER  - 
TY  - CHAP
A1  - Hüning, Felix
A1  - Stüttgen, Marcel
T1  - Work in Progress: Interdisciplinary projects in times of COVID-19 crisis – challenges, risks and chances
T2  - 2021 IEEE Global Engineering Education Conference (EDUCON)
Y1  - 2021
U6  - http://dx.doi.org/10.1109/EDUCON46332.2021.9454006
SP  - 1175
EP  - 1179
ER  - 
TY  - CHAP
A1  - Hoegen, Anne von
A1  - Doncker, Rik W. De
A1  - Bragard, Michael
A1  - Hoegen, Svenja von
T1  - Problem-Based Learning in Automation Engineering: Performing a Remote Laboratory Session Serving Various Educational Attainments
T2  - 2021 IEEE Global Engineering Education Conference (EDUCON)
Y1  - 2021
U6  - http://dx.doi.org/10.1109/EDUCON46332.2021.9453925
SP  - 1605
EP  - 1614
ER  - 
TY  - JOUR
A1  - Harzheim, Thomas
A1  - Mühmel, Marc
A1  - Heuermann, Holger
T1  - A SFCW harmonic radar system for maritime search and rescue using passive and active tags
JF  - International Journal of Microwave and Wireless Technologies
N2  - This paper introduces a new maritime search and rescue system based on S-band illumination harmonic radar (HR). Passive and active tags have been developed and tested while attached to life jackets and a small boat. In this demonstration test carried out on the Baltic Sea, the system was able to detect and range the active tags up to a distance of 5800 m using an illumination signal transmit-power of 100 W. Special attention is given to the development, performance, and conceptual differences between passive and active tags used in the system. Guidelines for achieving a high HR dynamic range, including a system components description, are given and a comparison with other HR systems is performed. System integration with a commercial maritime X-band navigation radar is shown to demonstrate a solution for rapid search and rescue response and quick localization.
KW  - Radar
KW  - microwave measurements
KW  - harmonic radar
KW  - harmonic radar tags
KW  - nonlinear VNA measurements
Y1  - 2021
U6  - http://dx.doi.org/10.1017/S1759078721000520
VL  - 13
IS  - Special Issue 7
SP  - 691
EP  - 707
PB  - Cambridge University Press
CY  - Cambridge
ER  - 
TY  - CHAP
A1  - Ferrein, Alexander
A1  - Meeßen, Marcus
A1  - Limpert, Nicolas
A1  - Schiffer, Stefan
ED  - Lepuschitz, Wilfried
T1  - Compiling ROS Schooling Curricula via Contentual Taxonomies
T2  - Robotics in Education
Y1  - 2021
SN  - 978-3-030-67411-3
U6  - http://dx.doi.org/10.1007/978-3-030-67411-3_5
N1  - RiE: International Conference on Robotics in Education (RiE);
Advances in Intelligent Systems and Computing book series (AISC, volume 1316)
SP  - 49
EP  - 60
PB  - Springer
CY  - Cham
ER  - 
TY  - RPRT
A1  - Jaekel, C.
A1  - Klein, C.
A1  - Barth, R.
A1  - Roskos, H.
A1  - Kyas, G.
A1  - Schroeer, M.
A1  - Hüning, Felix
T1  - Dynamik von Nichtgleichgewichtszustaenden in Hochtemperatursupraleitern Abschlussbericht
N2  - Im Projekt wurden mit Hilfe zeitaufgeloester optischer Messtechniken Relaxations-Dynamiken von optisch angeregten Ladungstraegern und Hochfrequenzeigenschaften von Hochtemperatursupraleitern untersucht. Oberhalb der Sprungtemperatur wurden die Elektron-Phonon-Kopplungskonstanten fuer YBCO und BSCCO bestimmt. Dabei wurde erstmalig ein direkter Zusammenhang zwischen der Sprungtemperatur und der Kopplungstaerke gefunden. Der Kopplungsmechanismus enthaelt sowohl phononische als auch elektronische (spindynamische) Anteile. Unterhalb von T_c wird die Dynamik durch Aufbrechen und Rekombination von Cooper-Paaren bestimmt. Bei den Arbeiten zu den kohaerenten Phononen wurde ein Modell entwickelt, das das 'Anwerfen' der Phononen und das Amplitudenverhalten unterhalb der Sprungtemperatur erklaert. Als begleitende Untersuchungen wurden breitbandige Hochfrequenz-Messungen vorgenommen. Die Methode erlaubt die Untersuchung von Ladungstraegerdichten und von Streumechanismen. Erstmalig wurde in verspannten YBCO-Duennfilmen eine starke temperaturabhaengige Resonanz-Absorption beobachtet, die als Josephson-Plasmaresonanz an intrinsischen Kontakten identifiziert werden konnte. Die Nutzbarkeit dieser Kontakte fuer Bauelemente wurde durch einen Mikrowellendetektor demonstriert. Durch den Nachweis von emittierter gepulster Strahlung aus einer stromdurchflossenen supraleitenden Bruecke nach optischer Anregung wurde erstmals die Einsatzmoeglichkeit von HTSL fuer schnelle optische Schalter demonstriert. Es wurde gezeigt, dass die Schaltgeschwindigkeit eine direkte Folge der Ladungstraegerdynamik ist.
T2  - Dynamics of non-equilibrium states in HTSC. Final report
KW  - Relaxation
KW  - Phonons
KW  - Calcium oxides
KW  - Electron-phonon coupling
Y1  - 1996
N1  - Foerderkennzeichen BMBF 13N6288; TRN: DE97FD184
ER  - 
TY  - CHAP
A1  - Heuermann, Holger
A1  - Harzheim, Thomas
A1  - Mühmel, Marc
T1  - A maritime harmonic radar search and rescue system using passive and active tags
T2  - 2020 17th European Radar Conference (EuRAD)
KW  - Harmonic Radar
KW  - Rescue System
KW  - Frequency Doubler
KW  - Transponder
KW  - Tag
Y1  - 2021
SN  - 978-2-87487-061-3
U6  - http://dx.doi.org/10.1109/EuRAD48048.2021.00030
N1  - Proceedings of the 17th European Radar Conference, 
13th - 15th January 2021, Utrecht, Netherlands
SP  - 73
EP  - 76
PB  - IEEE
ER  - 
TY  - JOUR
A1  - Roepke, Rene
A1  - Köhler, Klemens
A1  - Drury, Vincent
A1  - Schroeder, Ulrik
A1  - Wolf, Martin
A1  - Meyer, Ulrike
T1  - A pond full of phishing games - analysis of learning games for anti-phishing education
JF  - Model-driven Simulation and Training Environments for Cybersecurity. MSTEC 2020
N2  - Game-based learning is a promising approach to anti-phishing education, as it fosters motivation and can help reduce the perceived difficulty of the educational material. Over the years, several prototypes for game-based applications have been proposed, that follow different approaches in content selection, presentation, and game mechanics. In this paper, a literature and product review of existing learning games is presented. Based on research papers and accessible applications, an in-depth analysis was conducted, encompassing target groups, educational contexts, learning goals based on Bloom’s Revised Taxonomy, and learning content. As a result of this review, we created the publications on games (POG) data set for the domain of anti-phishing education. While there are games that can convey factual and conceptual knowledge, we find that most games are either unavailable, fail to convey procedural knowledge or lack technical depth. Thus, we identify potential areas of improvement for games suitable for end-users in informal learning contexts.
Y1  - 2020
SN  - 978-3-030-62433-0
U6  - http://dx.doi.org/10.1007/978-3-030-62433-0_32020
N1  - Lecture Notes in Computer Science, vol 12512
SP  - 41
EP  - 60
PB  - Springer
CY  - Cham
ER  - 
TY  - CHAP
A1  - Hoegen, Anne von
A1  - Doncker, Rik W. De
A1  - Rütters, René
T1  - Teaching Digital Control of Operational Amplifier Processes with a LabVIEW Interface and Embedded Hardware
T2  - The 23rd International Conference on Electrical Machines and Systems (ICEMS), Hamamatsu, Japan
Y1  - 2020
U6  - http://dx.doi.org/10.23919/ICEMS50442.2020.9290928
SP  - 1117
EP  - 1122
ER  - 
TY  - JOUR
A1  - Hüning, Felix
A1  - Backes, Andreas
T1  - Direct observation of large Barkhausen jump in thin Vicalloy wires
JF  - IEEE Magnetics Letters
Y1  - 2020
SN  - 1949-307X
U6  - http://dx.doi.org/10.1109/LMAG.2020.3046411
VL  - 11
IS  - Art. 2506504
SP  - 1
EP  - 4
PB  - IEEE
CY  - New York, NY
ER  - 
TY  - CHAP
A1  - Hofmann, Till
A1  - Limpert, Nicolas
A1  - Mataré, Viktor
A1  - Ferrein, Alexander
A1  - Lakemeyer, Gerhard
T1  - Winning the RoboCup Logistics League with Fast Navigation, Precise Manipulation, and Robust Goal Reasoning
T2  - RoboCup 2019: Robot World Cup XXIII. RoboCup
Y1  - 2019
SN  - 978-3-030-35699-6
U6  - http://dx.doi.org/10.1007/978-3-030-35699-6_41
N1  - Lecture Notes in Computer Science, vol 11531
SP  - 504
EP  - 516
PB  - Springer
CY  - Cham
ER  - 
TY  - CHAP
A1  - Ibanez-Sanchez, Gema
A1  - Wolf, Martin
T1  - Interactive Process Mining-Induced Change Management Methodology for Healthcare
T2  - Interactive Process Mining in Healthcare
N2  - The adoption of the Digital Health Transformation is a tremendous paradigm change in health organizations, which is not a trivial process in reality. For that reason, in this chapter, it is proposed a methodology with the objective to generate a changing culture in healthcare organisations. Such a change culture is essential for the successful implementation of any supporting methods like Interactive Process Mining. It needs to incorporate (mostly) new ways of team-based and evidence-based approaches for solving structural problems in a digital healthcare environment.
KW  - Methodology
KW  - Change culture
KW  - Lean thinking
KW  - Interactive process mining
KW  - Objective data
Y1  - 2020
SN  - 978-3-030-53993-1 (Online)
SN  - 978-3-030-53992-4 (Print)
U6  - http://dx.doi.org/10.1007/978-3-030-53993-1_16
SP  - 267
EP  - 293
PB  - Springer
CY  - Cham
ER  - 
TY  - JOUR
A1  - Fagan, Andrew J.
A1  - Bitz, Andreas
A1  - Björkman-Burtscher, Isabella M.
A1  - Collins, Christopher M.
A1  - Kimbrell, Vera
A1  - Raaijmakers, Alexander J. E.
T1  - 7T MR Safety
JF  - Journal of Magnetic Resonance Imaging (JMRI)
Y1  - 2021
U6  - http://dx.doi.org/10.1002/jmri.27319
SN  - 1522-2586
VL  - 53
IS  - 2
SP  - 333
EP  - 346
PB  - Wiley
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Fiedler, Thomas M.
A1  - Ladd, Mark E.
A1  - Clemens, Markus
A1  - Bitz, Andreas
T1  - Safety of subjects during radiofrequency exposure in ultra-high-field magnetic resonance imaging
JF  - IEEE Letters on Electromagnetic Compatibility Practice and Applications
N2  - Magnetic resonance imaging (MRI) is one of the most important medical imaging techniques. Since the introduction of MRI in the mid-1980s, there has been a continuous trend toward higher static magnetic fields to obtain i.a. a higher signal-to-noise ratio. The step toward ultra-high-field (UHF) MRI at 7 Tesla and higher, however, creates several challenges regarding the homogeneity of the spin excitation RF transmit field and the RF exposure of the subject. In UHF MRI systems, the wavelength of the RF field is in the range of the diameter of the human body, which can result in inhomogeneous spin excitation and local SAR hotspots. To optimize the homogeneity in a region of interest, UHF MRI systems use parallel transmit systems with multiple transmit antennas and time-dependent modulation of the RF signal in the individual transmit channels. Furthermore, SAR increases with increasing field strength, while the SAR limits remain unchanged. Two different approaches to generate the RF transmit field in UHF systems using antenna arrays close and remote to the body are investigated in this letter. Achievable imaging performance is evaluated compared to typical clinical RF transmit systems at lower field strength. The evaluation has been performed under consideration of RF exposure based on local SAR and tissue temperature. Furthermore, results for thermal dose as an alternative RF exposure metric are presented.
Y1  - 2020
SN  - 2637-6423
U6  - http://dx.doi.org/10.1109/LEMCPA.2020.3029747
VL  - 2
IS  - 3
SP  - 1
EP  - 8
PB  - IEEE
CY  - New York, NY
ER  - 
TY  - JOUR
A1  - Serror, Martin
A1  - Hack, Sacha
A1  - Henze, Martin
A1  - Schuba, Marko
A1  - Wehrle, Klaus
T1  - Challenges and Opportunities in Securing the Industrial Internet of Things
JF  - IEEE Transactions on Industrial Informatics
Y1  - 2021
U6  - http://dx.doi.org/10.1109/TII.2020.3023507
SN  - 1941-0050
VL  - 17
IS  - 5
SP  - 2985
EP  - 2996
PB  - IEEE
CY  - New York
ER  - 
TY  - CHAP
A1  - Eltester, Niklas Sebastian
A1  - Ferrein, Alexander
A1  - Schiffer, Stefan
T1  - A smart factory setup based on the RoboCup logistics league
T2  - 2020 IEEE Conference on Industrial Cyberphysical Systems (ICPS)
N2  - In this paper we present SMART-FACTORY, a setup for a research and teaching facility in industrial robotics that is based on the RoboCup Logistics League. It is driven by the need for developing and applying solutions for digital production. Digitization receives constantly increasing attention in many areas, especially in industry. The common theme is to make things smart by using intelligent computer technology. Especially in the last decade there have been many attempts to improve existing processes in factories, for example, in production logistics, also with deploying cyber-physical systems. An initiative that explores challenges and opportunities for robots in such a setting is the RoboCup Logistics League. Since its foundation in 2012 it is an international effort for research and education in an intra-warehouse logistics scenario. During seven years of competition a lot of knowledge and experience regarding autonomous robots was gained. This knowledge and experience shall provide the basis for further research in challenges of future production. The focus of our SMART-FACTORY is to create a stimulating environment for research on logistics robotics, for teaching activities in computer science and electrical engineering programmes as well as for industrial users to study and explore the feasibility of future technologies. Building on a very successful history in the RoboCup Logistics League we aim to provide stakeholders with a dedicated facility oriented at their individual needs.
Y1  - 2020
U6  - http://dx.doi.org/10.1109/ICPS48405.2020.9274766
N1  - 2020 IEEE Conference on Industrial Cyberphysical Systems (ICPS), 10-12 June 2020, Tampere, Finland.
SP  - 297
EP  - 302
PB  - IEEE
ER  -