@inproceedings{StopforthDavrajhFerrein2017, author = {Stopforth, Riaan and Davrajh, Shaniel and Ferrein, Alexander}, title = {Design considerations of the duo fugam dual rotor UAV}, series = {2017 Pattern Recognition Association of South Africa and Robotics and Mechatronics (PRASA-RobMech)}, booktitle = {2017 Pattern Recognition Association of South Africa and Robotics and Mechatronics (PRASA-RobMech)}, isbn = {978-1-5386-2314-5}, doi = {10.1109/RoboMech.2017.8261115}, pages = {7 -- 13}, year = {2017}, language = {en} } @inproceedings{CordesGligorevicBlicharski2019, author = {Cordes, Sven and Gligorevic, Snjezana and Blicharski, Peter}, title = {Analysis of sine precision influence on DOA estimation using the MUSIC algorithm}, series = {2019 20th International Radar Symposium (IRS)}, booktitle = {2019 20th International Radar Symposium (IRS)}, isbn = {978-3-7369-9860-5}, doi = {10.23919/IRS.2019.8768162}, pages = {1 -- 10}, year = {2019}, language = {en} } @article{HofmannLimpertMatareetal.2018, author = {Hofmann, Till and Limpert, Nicolas and Matar{\´e}, Victor and Sch{\"o}nitz, Sebastian and Niemueller, Tim and Ferrein, Alexander and Lakemeyer, Gerhard}, title = {The Carologistics RoboCup Logistics Team 2018}, year = {2018}, abstract = {The Carologistics team participates in the RoboCup Logistics League for the seventh year. The RCLL requires precise vision, manipulation and path planning, as well as complex high-level decision making and multi-robot coordination. We outline our approach with an emphasis on recent modifications to those components. The team members in 2018 are David Bosen, Christoph Gollok, Mostafa Gomaa, Daniel Habering, Till Hofmann, Nicolas Limpert, Sebastian Sch{\"o}nitz, Morian Sonnet, Carsten Stoffels, and Tarik Viehmann. This paper is based on the last year's team description.}, language = {en} } @inproceedings{SadeghfamSadeghiAhangarElgamaletal.2019, author = {Sadeghfam, Arash and Sadeghi-Ahangar, A. and Elgamal, Abdelrahman and Heuermann, Holger}, title = {Design and Development of a Novel Self-Igniting Microwave Plasma Jet for Industrial Applications}, series = {IEEE MTT-S International Microwave Symposium Digest}, booktitle = {IEEE MTT-S International Microwave Symposium Digest}, isbn = {978-172811309-8}, pages = {63 -- 66}, year = {2019}, language = {en} } @inproceedings{GaldiHartungDugelay2019, author = {Galdi, Chiara and Hartung, Frank and Dugelay, Jean-Luc}, title = {Socrates: A database of realistic data for source camera recognition on smartphones}, series = {Proceedings of the 8th International Conference on Pattern Recognition Applications and Methods - Volume 1: ICPRAM}, booktitle = {Proceedings of the 8th International Conference on Pattern Recognition Applications and Methods - Volume 1: ICPRAM}, isbn = {978-989-758-351-3}, doi = {10.5220/0007403706480655}, pages = {648 -- 655}, year = {2019}, language = {en} } @article{SchmidtForkmannSchultzetal.2019, author = {Schmidt, Katharina and Forkmann, Katarina and Schultz, Heidrun and Gratz, Marcel and Bitz, Andreas and Wiech, Katja and Bingel, Ulrike}, title = {Enhanced Neural Reinstatement for Evoked Facial Pain Compared With Evoked Hand Pain}, series = {The Journal of Pain}, journal = {The Journal of Pain}, number = {In Press, Corrected Proof}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1526-5900}, doi = {10.1016/j.jpain.2019.03.003}, year = {2019}, language = {en} } @article{KoenigWolf2018, author = {K{\"o}nig, Johannes Alexander and Wolf, Martin}, title = {GHOST: An Evaluated Competence Developing Game for Cybersecurity Awareness Training}, series = {International Journal on Advances in Security}, volume = {11}, journal = {International Journal on Advances in Security}, number = {3 \& 4}, publisher = {IARIA Journals}, issn = {1942-2636}, pages = {274 -- 287}, year = {2018}, abstract = {To train end users how to interact with digital systems is indispensable to ensure a strong computer security. 'Competence Developing Game'-based approaches are particularly suitable for this purpose because of their motivation-and simulation-aspects. In this paper the Competence Developing Game 'GHOST' for cybersecurity awareness trainings and its underlying patterns are described. Accordingly, requirements for an 'Competence Developing Game' based training are discussed. Based on these requirements it is shown how a game can fulfill these requirements. A supplementary game interaction design and a corresponding evaluation study is shown. The combination of training requirements and interaction design is used to create a 'Competence Developing Game'-based training concept. A part of these concept is implemented into a playable prototype that serves around one hour of play respectively training time. This prototype is used to perform an evaluation of the game and training aspects of the awareness training. Thereby, the quality of the game aspect and the effectiveness of the training aspect are shown.}, language = {en} } @inproceedings{FerreinSchollNeumannetal.2019, author = {Ferrein, Alexander and Scholl, Ingrid and Neumann, Tobias and Kr{\"u}ckel, Kai and Schiffer, Stefan}, title = {A system for continuous underground site mapping and exploration}, doi = {10.5772/intechopen.85859}, pages = {16 Seiten}, year = {2019}, language = {en} } @inproceedings{FerreinBharatheeshaSchifferetal.2019, author = {Ferrein, Alexander and Bharatheesha, Mukunda and Schiffer, Stefan and Corbato, Carlos Hernandez}, title = {TRROS 2018 : Teaching Robotics with ROS Workshop at ERF 2018; Proceedings of the Workshop on Teaching Robotics with ROS (held at ERF 2018), co-located with European Robotics Forum 2018 (ERF 2018), Tampere, Finland, March 15th, 2018}, series = {CEUR Workshop Proceedings}, booktitle = {CEUR Workshop Proceedings}, number = {Vol-2329}, issn = {1613-0073}, pages = {68 Seiten}, year = {2019}, language = {en} } @article{SchoppBritunVoracetal.2019, author = {Schopp, Christoph and Britun, Nikolay and Vorac, Jan and Synek, Petr and Snyders, Rony and Heuermann, Holger}, title = {Thermal and Optical Study on the Frequency Dependence of an Atmospheric Microwave Argon Plasma Jet}, series = {IEEE Transactions on Plasma Science}, volume = {47}, journal = {IEEE Transactions on Plasma Science}, number = {7}, publisher = {IEEE}, address = {New York}, issn = {1939-9375}, pages = {3176 -- 3181}, year = {2019}, language = {en} } @inproceedings{WeberWolf2017, author = {Weber, Niklas and Wolf, Martin}, title = {Datenerhebung f{\"u}r die CDG-Forschung}, series = {Prozesse, Technologie, Anwendungen, Systeme und Management 2017 : angewandte Forschung in der Wirtschaftsinformatik : Tagungsband zur 30. AKWI-Jahrestagung vom 17.09.2017 bis 20.09.2017 an der Hochschule Aschaffenburg / Arbeitskreis Wirtschaftsinformatik an Fachhochschulen (AKWI)}, booktitle = {Prozesse, Technologie, Anwendungen, Systeme und Management 2017 : angewandte Forschung in der Wirtschaftsinformatik : Tagungsband zur 30. AKWI-Jahrestagung vom 17.09.2017 bis 20.09.2017 an der Hochschule Aschaffenburg / Arbeitskreis Wirtschaftsinformatik an Fachhochschulen (AKWI)}, editor = {Barton, Thomas}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-56-3}, pages = {218 -- 227}, year = {2017}, language = {de} } @article{NoureddineKraffLaddetal.2019, author = {Noureddine, Yacine and Kraff, Oliver and Ladd, Mark E. and Wrede, Karsten and Chen, Bixia and Quick, Harald H. and Schaefers, Georg and Bitz, Andreas}, title = {Radiofrequency induced heating around aneurysm clips using a generic birdcage head coil at 7 Tesla under consideration of the minimum distance to decouple multiple aneurysm clips}, series = {Magnetic Resonance in Medicine}, journal = {Magnetic Resonance in Medicine}, number = {Early view}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.27835}, pages = {1 -- 17}, year = {2019}, language = {en} } @article{ClaerFerreinSchiffer2019, author = {Claer, Mario and Ferrein, Alexander and Schiffer, Stefan}, title = {Calibration of a Rotating or Revolving Platform with a LiDAR Sensor}, series = {Applied Sciences}, volume = {Volume 9}, journal = {Applied Sciences}, number = {issue 11, 2238}, publisher = {MDPI}, address = {Basel}, issn = {2076-3417}, doi = {10.3390/app9112238}, pages = {18 Seiten}, year = {2019}, language = {en} } @inproceedings{DonnerRabelScholletal.2019, author = {Donner, Ralf and Rabel, Matthias and Scholl, Ingrid and Ferrein, Alexander and Donner, Marc and Geier, Andreas and John, Andr{\´e} and K{\"o}hler, Christian and Varga, Sebastian}, title = {Die Extraktion bergbaulich relevanter Merkmale aus 3D-Punktwolken eines untertagetauglichen mobilen Multisensorsystems}, series = {Tagungsband Geomonitoring}, booktitle = {Tagungsband Geomonitoring}, doi = {10.15488/4515}, pages = {91 -- 110}, year = {2019}, language = {de} } @inproceedings{SteinbauerFerrein2019, author = {Steinbauer, Gerald and Ferrein, Alexander}, title = {CogRob 2018 : Cognitive Robotics Workshop. Proceedings of the 11th Cognitive Robotics Workshop 2018 co-located with 16th International Conference on Principles of Knowledge Representation and Reasoning (KR 2018). Tempe, AZ, USA, October 27th, 2018.}, series = {CEUR workshop proceedings}, booktitle = {CEUR workshop proceedings}, number = {Vol-2325}, issn = {1613-0073}, pages = {46 Seiten}, year = {2019}, language = {en} } @inproceedings{SchifferBragard2019, author = {Schiffer, Fabian and Bragard, Michael}, title = {Cascaded LQ and Field-Oriented Control of a Mobile Inverse Pendulum (Segway) with Permanent Magnet Synchronous Machines}, series = {2019 20th International Conference on Research and Education in Mechatronics (REM)}, booktitle = {2019 20th International Conference on Research and Education in Mechatronics (REM)}, isbn = {978-1-5386-9257-8}, doi = {10.1109/REM.2019.8744101}, pages = {1 -- 8}, year = {2019}, language = {en} } @inproceedings{BragardSubeSchneideretal.2019, author = {Bragard, Michael and Sube, Maike and Schneider, Maike and Jungemann, Christoph}, title = {Introducing a Cross-University Bachelor's Programme with Orientation Semester - Enabling a Permeable Academic Education System}, series = {2019 20th International Conference on Research and Education in Mechatronics (REM)}, booktitle = {2019 20th International Conference on Research and Education in Mechatronics (REM)}, isbn = {978-1-5386-9257-8}, doi = {10.1109/REM.2019.8744132}, pages = {1 -- 6}, year = {2019}, language = {en} } @article{OrzadaFiedlerBitzetal.2020, author = {Orzada, Stephan and Fiedler, Thomas M. and Bitz, Andreas and Ladd, Mark E. and Quick, Harald H.}, title = {Local SAR compression with overestimation control to reduce maximum relative SAR overestimation and improve multi-channel RF array performance}, series = {Magnetic Resonance Materials in Physics, Biology and Medicine}, journal = {Magnetic Resonance Materials in Physics, Biology and Medicine}, number = {34 (2021)}, publisher = {Springer}, address = {Heidelberg}, isbn = {1352-8661}, doi = {10.1007/s10334-020-00890-0}, pages = {153 -- 164}, year = {2020}, abstract = {Objective In local SAR compression algorithms, the overestimation is generally not linearly dependent on actual local SAR. This can lead to large relative overestimation at low actual SAR values, unnecessarily constraining transmit array performance. Method Two strategies are proposed to reduce maximum relative overestimation for a given number of VOPs. The first strategy uses an overestimation matrix that roughly approximates actual local SAR; the second strategy uses a small set of pre-calculated VOPs as the overestimation term for the compression. Result Comparison with a previous method shows that for a given maximum relative overestimation the number of VOPs can be reduced by around 20\% at the cost of a higher absolute overestimation at high actual local SAR values. Conclusion The proposed strategies outperform a previously published strategy and can improve the SAR compression where maximum relative overestimation constrains the performance of parallel transmission.}, language = {en} } @inproceedings{WiegnerVolkerMainzetal.2022, author = {Wiegner, Jonas and Volker, Hanno and Mainz, Fabian and Backes, Andreas and L{\"o}ken, Michael and H{\"u}ning, Felix}, title = {Wiegand-effect-powered wireless IoT sensor node}, series = {ITG-Fb. 303: Sensoren und Messsysteme}, booktitle = {ITG-Fb. 303: Sensoren und Messsysteme}, publisher = {VDE Verlag GmbH}, address = {Berlin}, isbn = {978-3-8007-5835-7}, pages = {255 -- 260}, year = {2022}, abstract = {In this article we describe an Internet-of-Things sensing device with a wireless interface which is powered by the oftenoverlooked harvesting method of the Wiegand effect. The sensor can determine position, temperature or other resistively measurable quantities and can transmit the data via an ultra-low power ultra-wideband (UWB) data transmitter. With this approach we can energy-self-sufficiently acquire, process, and wirelessly transmit data in a pulsed operation. A proof-of-concept system was built up to prove the feasibility of the approach. The energy consumption of the system is analyzed and traced back in detail to the individual components, compared to the generated energy and processed to identify further optimization options. Based on the proof-of-concept, an application demonstrator was developed. Finally, we point out possible use cases.}, language = {en} } @inproceedings{LorenzAltherrPelz2020, author = {Lorenz, Imke-Sophie and Altherr, Lena and Pelz, Peter F.}, title = {Assessing and Optimizing the Resilience of Water Distribution Systems Using Graph-Theoretical Metrics}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, editor = {Neufeld, Janis S. and Buscher, Udo and Lasch, Rainer and M{\"o}st, Dominik and Sch{\"o}nberger, J{\"o}rn}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48439-2}, doi = {10.1007/978-3-030-48439-2_63}, pages = {521 -- 527}, year = {2020}, abstract = {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.}, 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} } @inproceedings{MuellerSchmittLeiseetal.2021, author = {M{\"u}ller, Tim M. and Schmitt, Andreas and Leise, Philipp and Meck, Tobias and Altherr, Lena and Pelz, Peter F. and Pfetsch, Marc E.}, title = {Validation of an optimized resilient water supply system}, series = {Uncertainty in Mechanical Engineering}, booktitle = {Uncertainty in Mechanical Engineering}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-77255-0}, doi = {10.1007/978-3-030-77256-7_7}, pages = {70 -- 80}, year = {2021}, abstract = {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.}, 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} } @incollection{StengerAltherrAbel2019, author = {Stenger, David and Altherr, Lena and Abel, Dirk}, title = {Machine learning and metaheuristics for black-box optimization of product families: a case-study investigating solution quality vs. computational overhead}, series = {Operations Research Proceedings 2018}, booktitle = {Operations Research Proceedings 2018}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-18499-5 (Print)}, doi = {10.1007/978-3-030-18500-8_47}, pages = {379 -- 385}, year = {2019}, abstract = {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.}, language = {en} } @inproceedings{ChajanSchulteTiggesRekeetal.2021, author = {Chajan, Eduard and Schulte-Tigges, Joschua and Reke, Michael and Ferrein, Alexander and Matheis, Dominik and Walter, Thomas}, title = {GPU based model-predictive path control for self-driving vehicles}, series = {IEEE Intelligent Vehicles Symposium (IV)}, booktitle = {IEEE Intelligent Vehicles Symposium (IV)}, publisher = {IEEE}, address = {New York, NY}, isbn = {978-1-7281-5394-0}, doi = {10.1109/IV48863.2021.9575619}, pages = {1243 -- 1248}, year = {2021}, abstract = {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.}, language = {en} } @inproceedings{HueningWacheMagiera2021, author = {H{\"u}ning, Felix and Wache, Franz-Josef and Magiera, David}, title = {Redundant bus systems using dual-mode radio}, series = {Proceedings of Sixth International Congress on Information and Communication Technology}, booktitle = {Proceedings of Sixth International Congress on Information and Communication Technology}, publisher = {Springer}, address = {Singapore}, isbn = {978-981-16-2379-0}, doi = {10.1007/978-981-16-2380-6_73}, pages = {835 -- 842}, year = {2021}, abstract = {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.}, language = {en} } @inproceedings{MeckMuellerAltherretal.2020, author = {Meck, Marvin M. and M{\"u}ller, Tim M. and Altherr, Lena and Pelz, Peter F.}, title = {Improving an industrial cooling system using MINLP, considering capital and operating costs}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48438-5 (Print)}, doi = {10.1007/978-3-030-48439-2_61}, pages = {505 -- 512}, year = {2020}, abstract = {The chemical industry is one of the most important industrial sectors in Germany in terms of manufacturing revenue. While thermodynamic boundary conditions often restrict the scope for reducing the energy consumption of core processes, secondary processes such as cooling offer scope for energy optimisation. In this contribution, we therefore model and optimise an existing cooling system. The technical boundary conditions of the model are provided by the operators, the German chemical company BASF SE. In order to systematically evaluate different degrees of freedom in topology and operation, we formulate and solve a Mixed-Integer Nonlinear Program (MINLP), and compare our optimisation results with the existing system.}, language = {en} } @article{MuellerLeiseLorenzetal.2020, author = {M{\"u}ller, Tim M. and Leise, Philipp and Lorenz, Imke-Sophie and Altherr, Lena and Pelz, Peter F.}, title = {Optimization and validation of pumping system design and operation for water supply in high-rise buildings}, series = {Optimization and Engineering}, volume = {2021}, journal = {Optimization and Engineering}, number = {22}, publisher = {Springer}, issn = {1573-2924}, doi = {10.1007/s11081-020-09553-4}, pages = {643 -- 686}, year = {2020}, abstract = {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.}, language = {en} } @inproceedings{MuellerAltherrLeiseetal.2020, author = {M{\"u}ller, Tim M. and Altherr, Lena and Leise, Philipp and Pelz, Peter F.}, title = {Optimization of pumping systems for buildings: Experimental validation of different degrees of model detail on a modular test rig}, series = {Operations Research Proceedings 2019}, booktitle = {Operations Research Proceedings 2019}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-48438-5}, doi = {10.1007/978-3-030-48439-2_58}, pages = {481 -- 488}, year = {2020}, abstract = {Successful optimization requires an appropriate model of the system under consideration. When selecting a suitable level of detail, one has to consider solution quality as well as the computational and implementation effort. In this paper, we present a MINLP for a pumping system for the drinking water supply of high-rise buildings. We investigate the influence of the granularity of the underlying physical models on the solution quality. Therefore, we model the system with a varying level of detail regarding the friction losses, and conduct an experimental validation of our model on a modular test rig. Furthermore, we investigate the computational effort and show that it can be reduced by the integration of domain-specific knowledge.}, language = {en} } @article{AltherrLeisePfetschetal.2018, author = {Altherr, Lena and Leise, Philipp and Pfetsch, Marc E. and Schmitt, Andreas}, title = {Algorithmic design and resilience assessment of energy efficient high-rise water supply systems}, series = {Applied Mechanics and Materials}, volume = {885}, journal = {Applied Mechanics and Materials}, publisher = {Trans Tech Publications}, address = {B{\"a}ch}, issn = {1662-7482}, doi = {10.4028/www.scientific.net/AMM.885.211}, pages = {211 -- 223}, year = {2018}, abstract = {High-rise water supply systems provide water flow and suitable pressure in all levels of tall buildings. To design such state-of-the-art systems, the consideration of energy efficiency and the anticipation of component failures are mandatory. In this paper, we use Mixed-Integer Nonlinear Programming to compute an optimal placement of pipes and pumps, as well as an optimal control strategy.Moreover, we consider the resilience of the system to pump failures. A resilient system is able to fulfill a predefined minimum functionality even though components fail or are restricted in their normal usage. We present models to measure and optimize the resilience. To demonstrate our approach, we design and analyze an optimal resilient decentralized water supply system inspired by a real-life hotel building.}, language = {en} } @incollection{PfetschAbeleAltherretal.2021, author = {Pfetsch, Marc E. and Abele, Eberhard and Altherr, Lena and B{\"o}lling, Christian and Br{\"o}tz, Nicolas and Dietrich, Ingo and Gally, Tristan and Geßner, Felix and Groche, Peter and Hoppe, Florian and Kirchner, Eckhard and Kloberdanz, Hermann and Knoll, Maximilian and Kolvenbach, Philip and Kuttich-Meinlschmidt, Anja and Leise, Philipp and Lorenz, Ulf and Matei, Alexander and Molitor, Dirk A. and Niessen, Pia and Pelz, Peter F. and Rexer, Manuel and Schmitt, Andreas and Schmitt, Johann M. and Schulte, Fiona and Ulbrich, Stefan and Weigold, Matthias}, title = {Strategies for mastering uncertainty}, series = {Mastering uncertainty in mechanical engineering}, booktitle = {Mastering uncertainty in mechanical engineering}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-78353-2}, doi = {10.1007/978-3-030-78354-9_6}, pages = {365 -- 456}, year = {2021}, abstract = {This chapter describes three general strategies to master uncertainty in technical systems: robustness, flexibility and resilience. It builds on the previous chapters about methods to analyse and identify uncertainty and may rely on the availability of technologies for particular systems, such as active components. Robustness aims for the design of technical systems that are insensitive to anticipated uncertainties. Flexibility increases the ability of a system to work under different situations. Resilience extends this characteristic by requiring a given minimal functional performance, even after disturbances or failure of system components, and it may incorporate recovery. The three strategies are described and discussed in turn. Moreover, they are demonstrated on specific technical systems.}, language = {en} } @article{FerreinSteinbauer2016, author = {Ferrein, Alexander and Steinbauer, Gerald}, title = {20 Years of RoboCup - A Subjective Retrospection}, series = {KI - K{\"u}nstliche Intelligenz}, volume = {30}, journal = {KI - K{\"u}nstliche Intelligenz}, number = {3}, publisher = {Springer}, address = {Berlin}, issn = {1610-1987}, doi = {10.1007/s13218-016-0449-5}, pages = {225 -- 232}, year = {2016}, abstract = {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.}, language = {en} } @article{OrzadaJohstMaderwaldetal.2013, author = {Orzada, Stephan and Johst, S{\"o}ren and Maderwald, Stefan and Bitz, Andreas and Solbach, Klaus and Ladd, Mark E.}, title = {Mitigation of B1(+) inhomogeneity on single-channel transmit systems with TIAMO}, series = {Magnetic Resonance in Medicine}, volume = {70}, journal = {Magnetic Resonance in Medicine}, number = {1}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.24453}, pages = {290 -- 294}, year = {2013}, language = {en} } @article{OrzadaMaderwaldPoseretal.2012, author = {Orzada, S. and Maderwald, S. and Poser, B. A. and Johst, S. and Kannengiesser, S. and Ladd, M. E. and Bitz, Andreas}, title = {Time-interleaved acquisition of modes: an analysis of SAR and image contrast implications}, series = {Magnetic Resonance in Medicine}, volume = {67}, journal = {Magnetic Resonance in Medicine}, number = {4}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2594}, doi = {10.1002/mrm.23081}, pages = {1033 -- 1041}, year = {2012}, abstract = {s the magnetic field strength and therefore the operational frequency in MRI are increased, the radiofrequency wavelength approaches the size of the human head/body, resulting in wave effects which cause signal decreases and dropouts. Especially, whole-body imaging at 7 T and higher is therefore challenging. Recently, an acquisition scheme called time-interleaved acquisition of modes has been proposed to tackle the inhomogeneity problems in high-field MRI. The basic premise is to excite two (or more) different Burn:x-wiley:07403194:media:MRM23081:tex2gif-stack-1 modes using static radiofrequency shimming in an interleaved acquisition, where the complementary radiofrequency patterns of the two modes can be exploited to improve overall signal homogeneity. In this work, the impact of time-interleaved acquisition of mode on image contrast as well as on time-averaged specific absorption rate is addressed in detail. Time-interleaved acquisition of mode is superior in Burn:x-wiley:07403194:media:MRM23081:tex2gif-stack-2 homogeneity compared with conventional radiofrequency shimming while being highly specific absorption rate efficient. Time-interleaved acquisition of modes can enable almost homogeneous high-field imaging throughout the entire field of view in PD, T2, and T2*-weighted imaging and, if a specified homogeneity criterion is met, in T1-weighted imaging as well.}, language = {en} } @article{KobusBitzUdenetal.2012, author = {Kobus, Thiele and Bitz, Andreas and Uden, Mark J. van and Lagemaat, Miram W. and Rothgang, Eva and Orzada, Stephan and Heerschap, Arend and Scheenen, Tom W. J.}, title = {In vivo 31P MR spectroscopic imaging of the human prostate at 7 T: safety and feasibility}, series = {Magnetic Resonance in Medicine}, volume = {68}, journal = {Magnetic Resonance in Medicine}, number = {6}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2594}, doi = {10.1002/mrm.24175}, pages = {1683 -- 1695}, year = {2012}, abstract = {31P MR spectroscopic imaging of the human prostate provides information about phosphorylated metabolites that could be used for prostate cancer characterization. The sensitivity of a magnetic field strength of 7 T might enable 3D 31P MR spectroscopic imaging with relevant spatial resolution in a clinically acceptable measurement time. To this end, a 31P endorectal coil was developed and combined with an eight-channel 1H body-array coil to relate metabolic information to anatomical location. An extensive safety validation was performed to evaluate the specific absorption rate, the radiofrequency field distribution, and the temperature distribution of both coils. This validation consisted of detailed Finite Integration Technique simulations, confirmed by MR thermometry and Burn:x-wiley:07403194:media:MRM24175:tex2gif-stack-1 measurements in a phantom and in vivo temperature measurements. The safety studies demonstrated that the presence of the 31P endorectal coil had no influence on the specific absorption rate levels and temperature distribution of the external eight-channel 1H array coil. To stay within a 10 g averaged local specific absorption rate of 10 W/kg, a maximum time-averaged input power of 33 W for the 1H array coil was allowed. For transmitting with the 31P endorectal coil, our safety limit of less than 1°C temperature increase in vivo during a 15-min MR spectroscopic imaging experiment was reached at a time-averaged input power of 1.9 W. With this power setting, a second in vivo measurement was performed on a healthy volunteer. Using adiabatic excitation, 3D 31P MR spectroscopic imaging produced spectra from the entire prostate in 18 min with a spatial resolution of 4 cm3. The spectral resolution enabled the separate detection of phosphocholine, phosphoethanolamine, inorganic phosphate, and other metabolites that could play an important role in the characterization of prostate cancer.}, language = {en} } @article{OrzadaMaderwaldPoseretal.2010, author = {Orzada, Stephan and Maderwald, Stefan and Poser, Benedikt Andreas and Bitz, Andreas and Quick, Harald H. and Ladd, Mark E.}, title = {RF excitation using time interleaved acquisition of modes (TIAMO) to address B1 inhomogeneity in high-field MRI}, series = {Magnetic Resonance in Medicine}, volume = {64}, journal = {Magnetic Resonance in Medicine}, number = {2}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2594}, doi = {10.1002/mrm.22527}, pages = {327 -- 333}, year = {2010}, abstract = {As the field strength and, therefore, the operational frequency in MRI is increased, the wavelength approaches the size of the human head/body, resulting in wave effects, which cause signal decreases and dropouts. Several multichannel approaches have been proposed to try to tackle these problems, including RF shimming, where each element in an array is driven by its own amplifier and modulated with a certain (constant) amplitude and phase relative to the other elements, and Transmit SENSE, where spatially tailored RF pulses are used. In this article, a relatively inexpensive and easy to use imaging scheme for 7 Tesla imaging is proposed to mitigate signal voids due to B1 field inhomogeneity. Two time-interleaved images are acquired using a different excitation mode for each. By forming virtual receive elements, both images are reconstructed together using GRAPPA to achieve a more homogeneous image, with only small SNR and SAR penalty in head and body imaging at 7 Tesla.}, language = {en} } @article{UmutluBitzMaderwaldetal.2013, author = {Umutlu, Lale and Bitz, Andreas and Maderwald, Stefan and Orzada, Stephan and Kinner, Sonja and Kraff, Oliver and Brote, Irina and Ladd, Susanne C. and Schroeder, Tobias and Forsting, Michael}, title = {Contrast-enhanced ultra-high-field liver MRI: a feasibility trial}, series = {European Journal of Radiology}, volume = {82}, journal = {European Journal of Radiology}, number = {5}, publisher = {Elsevier}, address = {Amsterdam}, issn = {0720-048X}, doi = {10.1016/j.ejrad.2011.07.004}, pages = {760 -- 767}, year = {2013}, language = {en} } @article{YazdanbakhshSolbachBitz2012, author = {Yazdanbakhsh, Pedram and Solbach, Klaus and Bitz, Andreas}, title = {Variable power combiner for RF mode shimming in 7-T MR imaging}, series = {IEEE Transaction on Biomedical Engineering}, volume = {59}, journal = {IEEE Transaction on Biomedical Engineering}, number = {9}, publisher = {IEEE}, address = {New York}, issn = {1558-2531}, doi = {10.1109/TBME.2012.2205926}, pages = {2549 -- 2557}, year = {2012}, abstract = {This contribution discusses the utilization of RF power in an MRI system with RF mode shimming which enables the superposition of circularly polarized modes of a transmit RF coil array driven by a Butler matrix. Since the required power for the individual modes can vary widely, mode-shimming can result in a significant underutilization of the total available RF power. A variable power combiner (VPC) is proposed to improve the power utilization: it can be realized as a reconfiguration of the MRI transmit system by the inclusion of one additional matrix network which receives the power from all transmit amplifiers at its input ports and provides any desired (combined) power distribution at its output ports by controlling the phase and amplitude of the amplifiers' input signals. The power distribution at the output ports of the VPC is then fed into the "mode" ports of the coil array Butler matrix in order to superimpose the spatial modes at the highest achievable power utilization. The VPC configuration is compared to the standard configuration of the transmit chain of our MRI system with 8 transmit channels and 16 coils. In realistic scenarios, improved power utilization was achieved from 17\% to 60\% and from 14\% to 55\% for an elliptical phantom and a region of interest in the abdomen, respectively, and an increase of the power utilization of 1 dB for a region of interest in the upper leg. In general, it is found that the VPC allows significant improvement in power utilization when the shimming solution demands only a few modes to be energized, while the technique can yield loss in power utilization in cases with many modes required at high power level.}, language = {en} } @article{ProchnowGebingLadageetal.2011, author = {Prochnow, Nora and Gebing, Tina and Ladage, Kerstin and Krause-Finkeldey, Dorothee and Ourdi, Abessamad El and Bitz, Andreas and Streckert, Joachim and Hansen, Volkert and Dermietzel, Rolf}, title = {Electromagnetic field effect or simply stress? Effects of UMTS exposure on hippocampal longterm plasticity in the context of procedure related hormone release}, series = {PLoS one}, volume = {6}, journal = {PLoS one}, number = {5}, publisher = {PLOS}, address = {San Francisco}, doi = {10.1371/journal.pone.0019437}, pages = {e19437}, year = {2011}, abstract = {Harmful effects of electromagnetic fields (EMF) on cognitive and behavioural features of humans and rodents have been controversially discussed and raised persistent concern about adverse effects of EMF on general brain functions. In the present study we applied radio-frequency (RF) signals of the Universal Mobile Telecommunications System (UMTS) to full brain exposed male Wistar rats in order to elaborate putative influences on stress hormone release (corticosteron; CORT and adrenocorticotropic hormone; ACTH) and on hippocampal derived synaptic long-term plasticity (LTP) and depression (LTD) as electrophysiological hallmarks for memory storage and memory consolidation. Exposure was computer controlled providing blind conditions. Nominal brain-averaged specific absorption rates (SAR) as a measure of applied mass-related dissipated RF power were 0, 2, and 10 W/kg over a period of 120 min. Comparison of cage exposed animals revealed, regardless of EMF exposure, significantly increased CORT and ACTH levels which corresponded with generally decreased field potential slopes and amplitudes in hippocampal LTP and LTD. Animals following SAR exposure of 2 W/kg (averaged over the whole brain of 2.3 g tissue mass) did not differ from the sham-exposed group in LTP and LTD experiments. In contrast, a significant reduction in LTP and LTD was observed at the high power rate of SAR (10 W/kg). The results demonstrate that a rate of 2 W/kg displays no adverse impact on LTP and LTD, while 10 W/kg leads to significant effects on the electrophysiological parameters, which can be clearly distinguished from the stress derived background. Our findings suggest that UMTS exposure with SAR in the range of 2 W/kg is not harmful to critical markers for memory storage and memory consolidation, however, an influence of UMTS at high energy absorption rates (10 W/kg) cannot be excluded.}, language = {en} } @article{OrzadaBitzSchaeferetal.2011, author = {Orzada, Stephan and Bitz, Andreas and Sch{\"a}fer, Lena C. and Ladd, Susanne C. and Ladd, Mark E. and Maderwald, Stefan}, title = {Open design eight-channel transmit/receive coil for high-resolution and real-time ankle imaging at 7 T}, series = {Medical Physics}, volume = {38}, journal = {Medical Physics}, number = {3}, publisher = {Wiley}, address = {Hoboken}, issn = {2473-4209}, doi = {10.1118/1.3553399}, pages = {1162 -- 1167}, year = {2011}, abstract = {Purpose: At 1.5 T, real-time MRI of joint movement has been shown to be feasible. However, 7 T, provides higher SNR and thus an improved potential for parallel imaging acceleration. The purpose of this work was to build an open, U-shaped eight-channel transmit/receive microstrip coil for 7 T MRI to enable high-resolution and real-time imaging of the moving ankle joint. Methods: A U-shaped eight-channel transmit/receive array for the human ankle was built.urn:x-wiley:00942405:mp3399:equation:mp3399-math-0001-parameters and urn:x-wiley:00942405:mp3399:equation:mp3399-math-0002-factor were measured. SAR calculations of different ankle postures were performed to ensure patient safety. Inhomogeneities in the transmit field consequent to the open design were compensated for by the use of static RF shimming. High-resolution and real-time imaging was performed in human volunteers. Results: The presented array showed good performance with regard to patient comfort and image quality. High acceleration factors of up to 4 are feasible without visible acceleration artifacts. Reasonable image homogeneity was achieved with RF shimming. Conclusions: Open, noncylindrical designs for transmit/receive coils are practical at 7 T and real-time imaging of the moving joint is feasible with the presented coil design.}, language = {en} } @article{KraffBitzDammannetal.2010, author = {Kraff, Oliver and Bitz, Andreas and Dammann, Philipp and Ladd, Susanne C. and Ladd, Mark E. and Quick, Harald H.}, title = {An eight-channel transmit/receive multipurpose coil for musculoskeletal MR imaging at 7 T}, series = {Medical Physics}, volume = {37}, journal = {Medical Physics}, number = {12}, publisher = {Wiley}, address = {Hoboken, NJ}, issn = {2473-4209}, doi = {10.1118/1.3517176}, pages = {6368 -- 6376}, year = {2010}, abstract = {Purpose: MRI plays a leading diagnostic role in assessing the musculoskeletal (MSK) system and is well established for most questions at clinically used field strengths (up to 3 T). However, there are still limitations in imaging early stages of cartilage degeneration, very fine tendons and ligaments, or in locating nerve lesions, for example. 7 T MRI of the knee has already received increasing attention in the current published literature, but there is a strong need to develop new radiofrequency (RF) coils to assess more regions of the MSK system. In this work, an eight-channel transmit/receive RF array was built as a multipurpose coil for imaging some of the thus far neglected regions. An extensive coil characterization protocol and first in vivo results of the human wrist, shoulder, elbow, knee, and ankle imaged at 7 T will be presented. Methods: Eight surface loop coils with a dimension ofurn:x-wiley:00942405:media:mp7176:mp7176-math-0001 were machined from FR4 circuit board material. To facilitate easy positioning, two coil clusters, each with four loop elements, were combined to one RF transmit/receive array. An overlapped and shifted arrangement of the coil elements was chosen to reduce the mutual inductance between neighboring coils. A phantom made of body-simulating liquid was used for tuning and matching on the bench. Afterward, the S-parameters were verified on a human wrist, elbow, and shoulder. For safety validation, a detailed compliance test was performed including full wave simulations of the RF field distribution and the corresponding specific absorption rate (SAR) for all joints. In vivo images of four volunteers were assessed with gradient echo and spin echo sequences modified to obtain optimal image contrast, full anatomic coverage, and the highest spatial resolution within a reasonable acquisition time. The performance of the RF coil was additionally evaluated by in vivo B1 mapping. Results: A comparison of B1 per unit power, flip angle distribution, and anatomic images showed a fairly homogeneous excitation for the smaller joints (elbow, wrist, and ankle), while for the larger joints, the shoulder and especially the knee, B1 inhomogeneities and limited penetration depth were more pronounced. However, the greater part of the shoulder joint could be imaged.In vivo images rendered very fine anatomic details such as fascicles of the median nerve and the branching of the nerve bundles. High-resolution images of cartilage, labrum, and tendons could be acquired. Additionally, turbo spin echo (TSE) and inversion recovery sequences performed very well. Conclusions: This study demonstrates that the concept of two four-channel transmit/receive RF arrays can be used as a multipurpose coil for high-resolutionin vivo MR imaging of the musculoskeletal system at 7 T. Not only gradient echo but also typical clinical and SAR-intensive sequences such as STIR and TSE performed well. Imaging of small structures and peripheral nerves could in particular benefit from this technique.}, language = {en} } @article{OrzadaLaddBitz2016, author = {Orzada, Stephan and Ladd, Mark E. and Bitz, Andreas}, title = {A method to approximate maximum local SAR in multichannel transmit MR systems without transmit phase information}, series = {Magnetic Resonance in Medicine}, volume = {78}, journal = {Magnetic Resonance in Medicine}, number = {2}, publisher = {International Society for Magnetic Resonance in Medicine}, issn = {1522-2594}, doi = {10.1002/mrm.26398}, pages = {805 -- 811}, year = {2016}, abstract = {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}, language = {en} } @article{ChenSchoembergKraffetal.2016, author = {Chen, Bixia and Schoemberg, Tobias and Kraff, Oliver and Dammann, Philipp and Bitz, Andreas and Schlamann, Marc and Quick, Harald H. and Ladd, Mark E. and Sure, Ulrich and Wrede, Karsten H.}, title = {Cranial fixation plates in cerebral magnetic resonance imaging: a 3 and 7 Tesla in vivo image quality study}, series = {Magnetic Resonance Materials in Physics, Biology and Medicine}, volume = {29}, journal = {Magnetic Resonance Materials in Physics, Biology and Medicine}, number = {3}, publisher = {Springer}, address = {Berlin}, issn = {1352-8661}, doi = {10.1007/s10334-016-0548-1}, pages = {389 -- 398}, year = {2016}, abstract = {Objective This study assesses and quantifies impairment of postoperative magnetic resonance imaging (MRI) at 7 Tesla (T) after implantation of titanium cranial fixation plates (CFPs) for neurosurgical bone flap fixation. Materials and methods The study group comprised five patients who were intra-individually examined with 3 and 7 T MRI preoperatively and postoperatively (within 72 h/3 months) after implantation of CFPs. Acquired sequences included T₁-weighted magnetization-prepared rapid-acquisition gradient-echo (MPRAGE), T₂-weighted turbo-spin-echo (TSE) imaging, and susceptibility-weighted imaging (SWI). Two experienced neurosurgeons and a neuroradiologist rated image quality and the presence of artifacts in consensus reading. Results Minor artifacts occurred around the CFPs in MPRAGE and T2 TSE at both field strengths, with no significant differences between 3 and 7 T. In SWI, artifacts were accentuated in the early postoperative scans at both field strengths due to intracranial air and hemorrhagic remnants. After resorption, the brain tissue directly adjacent to skull bone could still be assessed. Image quality after 3 months was equal to the preoperative examinations at 3 and 7 T. Conclusion Image quality after CFP implantation was not significantly impaired in 7 T MRI, and artifacts were comparable to those in 3 T MRI.}, language = {en} } @article{SchmidtForkmannSinkeetal.2016, author = {Schmidt, K. and Forkmann, K. and Sinke, C. and Gratz, M. and Bitz, Andreas and Bingel, U.}, title = {The differential effect of trigeminal vs. peripheral pain stimulation on visual processing and memory encoding is influenced by pain-related fear}, series = {NeuroImage}, volume = {134}, journal = {NeuroImage}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1053-8119}, doi = {10.1016/j.neuroimage.2016.03.026}, pages = {386 -- 395}, year = {2016}, abstract = {Compared to peripheral pain, trigeminal pain elicits higher levels of fear, which is assumed to enhance the interruptive effects of pain on concomitant cognitive processes. In this fMRI study we examined the behavioral and neural effects of trigeminal (forehead) and peripheral (hand) pain on visual processing and memory encoding. Cerebral activity was measured in 23 healthy subjects performing a visual categorization task that was immediately followed by a surprise recognition task. During the categorization task subjects received concomitant noxious electrical stimulation on the forehead or hand. Our data show that fear ratings were significantly higher for trigeminal pain. Categorization and recognition performance did not differ between pictures that were presented with trigeminal and peripheral pain. However, object categorization in the presence of trigeminal pain was associated with stronger activity in task-relevant visual areas (lateral occipital complex, LOC), memory encoding areas (hippocampus and parahippocampus) and areas implicated in emotional processing (amygdala) compared to peripheral pain. Further, individual differences in neural activation between the trigeminal and the peripheral condition were positively related to differences in fear ratings between both conditions. Functional connectivity between amygdala and LOC was increased during trigeminal compared to peripheral painful stimulation. Fear-driven compensatory resource activation seems to be enhanced for trigeminal stimuli, presumably due to their exceptional biological relevance.}, language = {en} } @article{BankOrzadaSmitsetal.2015, author = {Bank, Bart L. van de and Orzada, Stephan and Smits, Frits and Lagemaat, Miriam W. and Rodgers, Christopher T. and Bitz, Andreas and Scheenen, Tom W. J.}, title = {Optimized (31) P MRS in the human brain at 7 T with a dedicated RF coil setup}, series = {NMR in Biomedicine}, volume = {28}, journal = {NMR in Biomedicine}, number = {11}, publisher = {Wiley}, address = {Weinheim}, issn = {1099-1492}, doi = {10.1002/nbm.3422}, pages = {1570 -- 1578}, year = {2015}, language = {en} } @article{NoureddineBitzLaddetal.2015, author = {Noureddine, Yacine and Bitz, Andreas and Ladd, Mark E. and Th{\"u}rling, Markus and Ladd, Susanne C. and Schaefers, Gregor and Kraff, Oliver}, title = {Experience with magnetic resonance imaging of human subjects with passive implants and tattoos at 7 T: a retrospective study}, series = {Magnetic Resonance Materials in Physics, Biology and Medicine}, volume = {28}, journal = {Magnetic Resonance Materials in Physics, Biology and Medicine}, number = {6}, publisher = {Springer}, address = {Berlin}, issn = {1352-8661}, doi = {10.1007/s10334-015-0499-y}, pages = {577 -- 590}, year = {2015}, language = {en} } @article{LagemaatBreukelsVosetal.2016, author = {Lagemaat, Miriam W. and Breukels, Vincent and Vos, Eline K. and B., Adam and Uden, Mark J. van and Orzada, Stephan and Bitz, Andreas and Maas, Marnix C. and Scheenen, Tom W. J.}, title = {¹H MR spectroscopic imaging of the prostate at 7T using spectral-spatial pulses}, series = {Magnetic Resonance in Medicine}, volume = {75}, journal = {Magnetic Resonance in Medicine}, number = {3}, publisher = {International Society for Magnetic Resonance in Medicine}, issn = {1522-2594}, doi = {10.1002/mrm.25569}, pages = {933 -- 945}, year = {2016}, abstract = {Purpose To assess the feasibility of prostate ¹H MR spectroscopic imaging (MRSI) using low-power spectral-spatial (SPSP) pulses at 7T, exploiting accurate spectral selection and spatial selectivity simultaneously. Methods A double spin-echo sequence was equipped with SPSP refocusing pulses with a spectral selectivity of 1 ppm. Three-dimensional prostate ¹H-MRSI at 7T was performed with the SPSP-MRSI sequence using an 8-channel transmit array coil and an endorectal receive coil in three patients with prostate cancer and in one healthy subject. No additional water or lipid suppression pulses were used. Results Prostate ¹H-MRSI could be obtained well within specific absorption rate (SAR) limits in a clinically feasible time (10 min). Next to the common citrate signals, the prostate spectra exhibited high spermine signals concealing creatine and sometimes also choline. Residual lipid signals were observed at the edges of the prostate because of limitations in spectral and spatial selectivity. Conclusion It is possible to perform prostate ¹H-MRSI at 7T with a SPSP-MRSI sequence while using separate transmit and receive coils. This low-SAR MRSI concept provides the opportunity to increase spatial resolution of MRSI within reasonable scan times.}, language = {en} } @article{VosLagemaatBarentszetal.2014, author = {Vos, E. K. and Lagemaat, M. W. and Barentsz, J. O. and F{\"u}tterer, J. J. and Zamecnik, P. and Roozen, H. and Orzada, S. and Bitz, Andreas and Maas, M. C. and Scheenen, T. W. J.}, title = {Image quality and cancer visibility of T2-weighted Magnetic Resonance Imaging of the prostate at 7 Tesla}, series = {European Radiology}, volume = {24}, journal = {European Radiology}, number = {8}, publisher = {Springer}, address = {Cham}, issn = {1432-1084}, doi = {10.1007/s00330-014-3234-6}, pages = {1950 -- 1958}, year = {2014}, abstract = {Objectives To assess the image quality of T2-weighted (T2w) magnetic resonance imaging of the prostate and the visibility of prostate cancer at 7 Tesla (T). Materials \& methods Seventeen prostate cancer patients underwent T2w imaging at 7T with only an external transmit/receive array coil. Three radiologists independently scored images for image quality, visibility of anatomical structures, and presence of artefacts. Krippendorff's alpha and weighted kappa statistics were used to assess inter-observer agreement. Visibility of prostate cancer lesions was assessed by directly linking the T2w images to the confirmed location of prostate cancer on histopathology. Results T2w imaging at 7T was achievable with 'satisfactory' (3/5) to 'good' (4/5) quality. Visibility of anatomical structures was predominantly scored as 'satisfactory' (3/5) and 'good' (4/5). If artefacts were present, they were mostly motion artefacts and, to a lesser extent, aliasing artefacts and noise. Krippendorff's analysis revealed an α = 0.44 between three readers for the overall image quality scores. Clinically significant cancer lesions in both peripheral zone and transition zone were visible at 7T. Conclusion T2w imaging with satisfactory to good quality can be routinely acquired, and cancer lesions were visible in patients with prostate cancer at 7T using only an external transmit/receive body array coil.}, language = {en} } @article{LagemaatMaasVosetal.2015, author = {Lagemaat, Miriam W. and Maas, Marnix C. and Vos, Eline K. and Bitz, Andreas and Orzada, Stephan and Weiland, Elisabeth and Uden, Mark J. van and Kobus, Thiele and Heerschap, Arend and Scheenen, Tom W. J.}, title = {(31) P MR spectroscopic imaging of the human prostate at 7 T: T1 relaxation times, Nuclear Overhauser Effect, and spectral characterization}, series = {Magnetic Resonance in Medicine}, volume = {73}, journal = {Magnetic Resonance in Medicine}, number = {3}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.25209}, pages = {909 -- 920}, year = {2015}, language = {en} } @article{TheysohnKraffEilersetal.2014, author = {Theysohn, Jens M. and Kraff, Oliver and Eilers, Kristina and Andrade, Dorian and Gerwig, Marcus and Timmann, Dagmar and Schmitt, Franz and Ladd, Mark E. and Ladd, Susanne C. and Bitz, Andreas}, title = {Vestibular effects of a 7 Tesla MRI examination compared to 1.5 T and 0 T in healthy volunteers}, series = {PLoS one}, volume = {9}, journal = {PLoS one}, number = {3}, publisher = {PLOS}, address = {San Francisco}, issn = {1932-6203}, doi = {10.1371/journal.pone.0092104}, pages = {e92104}, year = {2014}, abstract = {Ultra-high-field MRI (7 Tesla (T) and above) elicits more temporary side-effects compared to 1.5 T and 3 T, e.g. dizziness or "postural instability" even after exiting the scanner. The current study aims to assess quantitatively vestibular performance before and after exposure to different MRI scenarios at 7 T, 1.5 T and 0 T. Sway path and body axis rotation (Unterberger's stepping test) were quantitatively recorded in a total of 46 volunteers before, 2 minutes after, and 15 minutes after different exposure scenarios: 7 T head MRI (n = 27), 7 T no RF (n = 22), 7 T only B₀ (n = 20), 7 T in \& out B₀ (n = 20), 1.5 T no RF (n = 20), 0 T (n = 15). All exposure scenarios lasted 30 minutes except for brief one minute exposure in 7 T in \& out B₀. Both measures were documented utilizing a 3D ultrasound system. During sway path evaluation, the experiment was repeated with eyes both open and closed. Sway paths for all long-lasting 7 T scenarios (normal, no RF, only B₀) with eyes closed were significantly prolonged 2 minutes after exiting the scanner, normalizing after 15 minutes. Brief exposure to 7 T B₀ or 30 minutes exposure to 1.5 T or 0 T did not show significant changes. End positions after Unterberger's stepping test were significantly changed counter-clockwise after all 7 T scenarios, including the brief in \& out B₀ exposure. Shorter exposure resulted in a smaller alteration angle. In contrast to sway path, reversal of changes in body axis rotation was incomplete after 15 minutes. 1.5 T caused no rotational changes. The results show that exposure to the 7 Tesla static magnetic field causes only a temporary dysfunction or "over-compensation" of the vestibular system not measurable at 1.5 or 0 Tesla. Radiofrequency fields, gradient switching, and orthostatic dysregulation do not seem to play a role.}, language = {en} } @article{KraffBitzBreyeretal.2011, author = {Kraff, Oliver and Bitz, Andreas and Breyer, Tobias and Kruszona, Stefan and Maderwald, Stefan and Brote, Irina and Gizewski, Elke R. and Ladd, Mark E. and Quick, Harald H.}, title = {A transmit/receive radiofrequency array for imaging the carotid arteries at 7 Tesla: coil design and first in vivo results}, series = {Investigative Radiology}, volume = {46}, journal = {Investigative Radiology}, number = {4}, publisher = {Wolters Kluwer}, address = {K{\"o}ln}, issn = {1536-0210}, doi = {10.1097/RLI.0b013e318206cee4}, pages = {246 -- 254}, year = {2011}, abstract = {Objective: To develop a transmit/receive radiofrequency (RF) array for magnetic resonance imaging (MRI) of the carotid arteries at 7 T. The prototype is characterized in numerical simulations and bench measurements, and the feasibility of plaque imaging at 7 T is demonstrated in first in vivo images. Materials and Methods: The RF phased array coil consists of 8 surface loop coils. To allow imaging of both sides of the neck, the RF array is divided into 2 coil clusters, each with 4 overlapping loop elements. For safety validation, numerical computations of the RF field distribution and the corresponding specific absorption rate were performed on the basis of a heterogeneous human body model. To validate the coil model, maps of the transmit B1+ field were compared between simulation and measurement. In vivo images of a healthy volunteer and a patient (ulcerating plaque and a 50\% stenosis of the right internal carotid artery) were acquired using a 3-dimensional FLASH sequence with a high isotropic spatial resolution of 0.54 mm as well as using pulse-triggered proton density (PD)/T2-weighted turbo spin echo sequences. Results: Measurements of the S-parameters yielded a reflection and isolation of the coil elements of better than -18 and -13 dB, respectively. Measurements of the g-factor indicated good image quality for parallel imaging acceleration factors up to 2.4. A similar distribution and a very good match of the absolute values were found between the measured and simulated B1+ transmit RF field for the validation of the coil model. In vivo images revealed good signal excitation of both sides of the neck and a high vessel-to-background image contrast for the noncontrast-enhanced 3-dimensional FLASH sequence. Imaging at 7 T could depict the extent of stenosis, and revealed the disruption and ulcer of the plaque. Conclusions: This study demonstrates that 2 four-channel transmit/receive RF arrays for each side of the neck is a suitable concept for in vivo MRI of the carotid arteries at 7 Tesla. Further studies are needed to explore and exploit the full potential of 7 T high-field MRI for carotid atherosclerotic plaque imaging.}, language = {en} } @article{ElQuardiStreckertBitzetal.2011, author = {El Quardi, A. and Streckert, J. and Bitz, Andreas and M{\"u}nkner, S. and Engel, J. and Hansen, V.}, title = {New fin-line devices for radiofrequency exposure of small biological samples in vitro allowing whole-cell patch clamp recordings}, series = {Bioelectromagnetics}, volume = {32}, journal = {Bioelectromagnetics}, number = {2}, publisher = {Wiley}, address = {Weinheim}, issn = {1521-186X}, doi = {10.1002/bem.20621}, pages = {102 -- 112}, year = {2011}, abstract = {The development and analysis of three waveguides for the exposure of small biological in vitro samples to mobile communication signals at 900 MHz (GSM, Global System for Mobile Communications), 1.8 GHz (GSM), and 2 GHz (UMTS, Universal Mobile Telecommunications System) is presented. The waveguides were based on a fin-line concept and the chamber containing the samples bathed in extracellular solution was placed onto two fins with a slot in between, where the exposure field concentrates. Measures were taken to allow for patch clamp recordings during radiofrequency (RF) exposure. The necessary power for the achievement of the maximum desired specific absorption rate (SAR) of 20 W/kg (average over the mass of the solution) was approximately Pin = 50 mW, Pin = 19 mW, and Pin = 18 mW for the 900 MHz, 1800 MHz, and 2 GHz devices, respectively. At 20 W/kg, a slight RF-induced temperature elevation in the solution of no more than 0.3 °C was detected, while no thermal offsets due to the electromagnetic exposure could be detected at the lower SAR settings (2, 0.2, and 0.02 W/kg). A deviation of 10\% from the intended solution volume yielded a calculated SAR deviation of 8\% from the desired value. A maximum ±10\% variation in the local SAR could occur when the position of the patch clamp electrode was altered within the area where the cells to be investigated were located.}, language = {en} } @article{SchlamannVoigtMaderwaldetal.2010, author = {Schlamann, Marc and Voigt, Melanie A. and Maderwald, Stefan and Bitz, Andreas and Kraff, Oliver and Ladd, Susanne C. and Ladd, Mark E. and Forsting, Michael and Wilhelm, Hans}, title = {Exposure to high-field MRI does not affect cognitive function}, series = {Journal of Magnetic Resonance Imaging}, volume = {31}, journal = {Journal of Magnetic Resonance Imaging}, number = {5}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2586}, doi = {10.1002/jmri.22065}, pages = {1061 -- 1066}, year = {2010}, abstract = {Purpose To assess potential cognitive deficits under the influence of static magnetic fields at various field strengths some studies already exist. These studies were not focused on attention as the most vulnerable cognitive function. Additionally, mostly no magnetic resonance imaging (MRI) sequences were performed. Materials and Methods In all, 25 right-handed men were enrolled in this study. All subjects underwent one MRI examination of 63 minutes at 1.5 T and one at 7 T within an interval of 10 to 30 days. The order of the examinations was randomized. Subjects were referred to six standardized neuropsychological tests strictly focused on attention immediately before and after each MRI examination. Differences in neuropsychological variables between the timepoints before and after each MRI examination were assessed and P-values were calculated Results Only six subtests revealed significant differences between pre- and post-MRI. In these tests the subjects achieved better results in post-MRI testing than in pre-MRI testing (P = 0.013-0.032). The other tests revealed no significant results. Conclusion The improvement in post-MRI testing is only explicable as a result of learning effects. MRI examinations, even in ultrahigh-field scanners, do not seem to have any persisting influence on the attention networks of human cognition immediately after exposure.}, language = {en} } @article{BitzZhouElQuardietal.2009, author = {Bitz, Andreas and Zhou, Yi and El Quardi, Abdessamad and Streckert, Joachim}, title = {Occupational Exposure at Mobile Communication Base Station Antenna Sites}, series = {Frequenz}, volume = {63}, journal = {Frequenz}, number = {7-8}, issn = {2191-6349}, doi = {10.1515/FREQ.2009.63.7-8.123}, pages = {123 -- 128}, year = {2009}, language = {en} } @article{SchlamannYoonMaderwaldetal.2010, author = {Schlamann, Marc and Yoon, Min-Suk and Maderwald, Stefan and Pietrzyk, Thomas and Bitz, Andreas and Gerwig, Marcus and Forsting, Michael and Ladd, Susanne C. and Ladd, Mark E. and Kastrup, Oliver}, title = {Short term effects of magnetic resonance imaging on excitability of the motor cortex at 1.5T and 7T}, series = {Academic Radiology}, volume = {17}, journal = {Academic Radiology}, number = {3}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1076-6332}, doi = {10.1016/j.acra.2009.10.004}, pages = {277 -- 281}, year = {2010}, abstract = {Rationale and Objectives The increasing spread of high-field and ultra-high-field magnetic resonance imaging (MRI) scanners has encouraged new discussion of the safety aspects of MRI. Few studies have been published on possible cognitive effects of MRI examinations. The aim of this study was to examine whether changes are measurable after MRI examinations at 1.5 and 7 T by means of transcranial magnetic stimulation (TMS). Materials and Methods TMS was performed in 12 healthy, right-handed male volunteers. First the individual motor threshold was specified, and then the cortical silent period (SP) was measured. Subsequently, the volunteers were exposed to the 1.5-T MRI scanner for 63 minutes using standard sequences. The MRI examination was immediately followed by another TMS session. Fifteen minutes later, TMS was repeated. Four weeks later, the complete setting was repeated using a 7-T scanner. Control conditions included lying in the 1.5-T scanner for 63 minutes without scanning and lying in a separate room for 63 minutes. TMS was performed in the same way in each case. For statistical analysis, Wilcoxon's rank test was performed. Results Immediately after MRI exposure, the SP was highly significantly prolonged in all 12 subjects at 1.5 and 7 T. The motor threshold was significantly increased. Fifteen minutes after the examination, the measured value tended toward normal again. Control conditions revealed no significant differences. Conclusion MRI examinations lead to a transient and highly significant alteration in cortical excitability. This effect does not seem to depend on the strength of the static magnetic field.}, language = {en} } @article{KraffBitzKruszonaetal.2009, author = {Kraff, Oliver and Bitz, Andreas and Kruszona, Stefan and Orzada, Stephan and Schaefer, Lena C. and Theysohn, Jens M. and Maderwald, Stefan and Ladd, Mark E. and Quick, Harald H.}, title = {An eight-channel phased array RF coil for spine MR imaging at 7 T}, series = {Investigative Radiology}, volume = {44}, journal = {Investigative Radiology}, number = {11}, publisher = {Lippincott Williams \& Wilkins}, issn = {1536-0210}, doi = {10.1097/RLI.0b013e3181b24ab7}, pages = {734 -- 740}, year = {2009}, language = {en} } @article{SchlamannYoonMaderwaldetal.2009, author = {Schlamann, M. and Yoon, M.-S. and Maderwald, S. and Pietrzyk, T. and Bitz, Andreas and Gerwig, M. and Forsting, M. and Ladd, S. C. and Ladd, M. E. and Kastrup, O.}, title = {Auswirkungen der Magnetresonanztomografie auf die Elektrophysiologie des motorischen Kortex: eine Studie mit transkranieller Magnetstimulation}, series = {R{\"o}Fo - Fortschritte auf dem Giebiet der R{\"o}ntgenstrahlen und der bildgebenden Verfahren}, volume = {181}, journal = {R{\"o}Fo - Fortschritte auf dem Giebiet der R{\"o}ntgenstrahlen und der bildgebenden Verfahren}, number = {3}, publisher = {Thieme}, address = {Stuttgart}, issn = {1438-9029}, doi = {10.1055/s-0028-1109038}, pages = {215 -- 219}, year = {2009}, language = {de} } @article{KlompBitzHeerschapetal.2009, author = {Klomp, D. W. J. and Bitz, Andreas and Heerschap, A. and Scheenen, T. W. J.}, title = {Proton spectroscopic imaging of the human prostate at 7 T}, series = {NMR in Biomedicine}, volume = {22}, journal = {NMR in Biomedicine}, number = {5}, issn = {1099-1492}, doi = {10.1002/nbm.1360}, pages = {495 -- 501}, year = {2009}, language = {en} } @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{FiedlerLaddBitz2017, author = {Fiedler, Thomas M. and Ladd, Mark E. and Bitz, Andreas}, title = {SAR Simulations \& Safety}, series = {NeuroImage}, journal = {NeuroImage}, number = {Epub ahead of print}, publisher = {Elsevier}, address = {Amsterdam}, issn = {1053-8119}, doi = {10.1016/j.neuroimage.2017.03.035}, year = {2017}, language = {en} } @article{NoureddineKraffLaddetal.2017, author = {Noureddine, Yacine and Kraff, Oliver and Ladd, Mark E. and Wrede, Karsten H. and Chen, Bixia and Quick, Harald H. and Schaefers, Gregor and Bitz, Andreas}, title = {In vitro and in silico assessment of RF-induced heating around intracranial aneurysm clips at 7 Tesla}, series = {Magnetic Resonance in Medicine}, journal = {Magnetic Resonance in Medicine}, number = {Early view}, publisher = {Wiley}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.26650}, pages = {14 Seiten}, year = {2017}, language = {en} } @article{FiedlerLaddBitz2017, author = {Fiedler, Thomas M. and Ladd, Mark E. and Bitz, Andreas}, title = {RF safety assessment of a bilateral four-channel transmit/receive 7 Tesla breast coil: SAR versus temperature limits}, series = {Medical Physics}, volume = {44}, journal = {Medical Physics}, number = {1}, doi = {10.1002/mp.12034}, pages = {143 -- 157}, year = {2017}, language = {en} } @article{LagemaatVosMaasetal.2014, author = {Lagemaat, Miriam W. and Vos, Eline K. and Maas, Marnix C. and Bitz, Andreas and Orzada, Stephan and Uden, Mark J. van and Kobus, Thiele and Heerschap, Arend and Scheenen, Tom W. J.}, title = {Phosphorus magnetic resonance spectroscopic imaging at 7 T in patients with prostate cancer}, series = {Investigative Radiology}, volume = {49}, journal = {Investigative Radiology}, number = {5}, publisher = {Lippincott Williams \& Wilkins}, address = {Philadelphia, Pa.}, issn = {1536-0210}, doi = {10.1097/RLI.0000000000000012}, pages = {363 -- 372}, year = {2014}, abstract = {Objectives The aim of this study was to identify characteristics of phosphorus (³¹P) spectra of the human prostate and to investigate changes of individual phospholipid metabolites in prostate cancer through in vivo ³¹P magnetic resonance spectroscopic imaging (MRSI) at 7 T. Materials and Methods In this institutional review board-approved study, 15 patients with biopsy-proven prostate cancer underwent T₂-weighted magnetic resonance imaging and 3-dimensional ³¹P MRSI at 7 T. Voxels were selected at the tumor location, in normal-appearing peripheral zone tissue, normal-appearing transition zone tissue, and in the base of the prostate close to the seminal vesicles. Phosphorus metabolite ratios were determined and compared between tissue types. Results Signals of phosphoethanolamine (PE) and phosphocholine (PC) were present and well resolved in most ³¹P spectra in the prostate. Glycerophosphocholine signals were observable in 43\% of the voxels in malignant tissue, but in only 10\% of the voxels in normal-appearing tissue away from the seminal vesicles. In many spectra, independent of tissue type, 2 peaks resonated in the chemical shift range of inorganic phosphate, possibly representing 2 separate pH compartments. The PC/PE ratio in the seminal vesicles was highly elevated compared with the prostate in 5 patients. A considerable overlap of ³¹P metabolite ratios was found between prostate cancer and normal-appearing prostate tissue, preventing direct discrimination of these tissues. The only 2 patients with high Gleason scores tumors (≥4+5) presented with high PC and glycerophosphocholine levels in their cancer lesions. Conclusions Phosphorus MRSI at 7 T shows distinct features of phospholipid metabolites in the prostate gland and its surrounding structures. In this exploratory study, no differences in ³¹P metabolite ratios were observed between prostate cancer and normal-appearing prostate tissue possibly because of the partial volume effects of small tumor foci in large MRSI voxels.}, language = {en} } @article{MaasVosLagemaatetal.2014, author = {Maas, Marnix C. and Vos, Eline K. and Lagemaat, Miriam W. and Bitz, Andreas and Orzada, Stephan and Kobus, Thiele and Kraff, Oliver and Maderwald, Stefan and Ladd, Mark E. and Scheenen, Tom W. J.}, title = {Feasibility of T₂-weighted turbo spin echo imaging of the human prostate at 7 tesla}, series = {Magnetic Resonance in Medicine}, volume = {71}, journal = {Magnetic Resonance in Medicine}, number = {5}, publisher = {Wiley-VCH}, address = {Weinheim}, issn = {1522-2594}, doi = {10.1002/mrm.24818}, pages = {1711 -- 1719}, year = {2014}, abstract = {Purpose To demonstrate that high quality T₂-weighted (T2w) turbo spin-echo (TSE) imaging of the complete prostate can be achieved routinely and within safety limits at 7 T, using an external transceive body array coil only. Methods Nine healthy volunteers and 12 prostate cancer patients were scanned on a 7 T whole-body system. Preparation consisted of B₀ and radiofrequency shimming and localized flip angle calibration. T₁ and T₂ relaxation times were measured and used to define the T2w-TSE protocol. T2w imaging was performed using a TSE sequence (pulse repetition time/echo time 3000-3640/71 ms) with prolonged excitation and refocusing pulses to reduce specific absorption rate. Results High quality T2w TSE imaging was performed in less than 2 min in all subjects. Tumors of patients with gold-standard tumor localization (MR-guided biopsy or prostatectomy) were well visualized on 7 T imaging (n = 3). The number of consecutive slices achievable within a 10-g averaged specific absorption rate limit of 10 W/kg was ≥28 in all subjects, sufficient for full prostate coverage with 3-mm slices in at least one direction. Conclusion High quality T2w TSE prostate imaging can be performed routinely and within specific absorption rate limits at 7 T with an external transceive body array.}, language = {en} } @article{UmutluKraffFischeretal.2013, author = {Umutlu, Lale and Kraff, Oliver and Fischer, Anja and Kinner, Sonja and Maderwald, Stefan and Nassenstein, Kai and Nensa, Felix and Gr{\"u}neisen, Johannes and Orzada, Stephan and Bitz, Andreas and Forsting, Michael and Ladd, Mark E. and Lauenstein, Thomas C.}, title = {Seven-Tesla MRI of the female pelvis}, series = {European Radiology}, volume = {23}, journal = {European Radiology}, number = {9}, publisher = {Springer}, address = {Berlin}, issn = {1432-1084}, doi = {10.1007/s00330-013-2868-0}, pages = {2364 -- 2373}, year = {2013}, language = {en} } @article{BitzFelderWittig2013, author = {Bitz, Andreas and Felder, Jorg and Wittig, Tilmann}, title = {Designing MRI Coils with Aid of Simulation}, series = {Microwaves \& RF}, volume = {52}, journal = {Microwaves \& RF}, number = {7}, publisher = {Penton}, address = {Cleveland, Ohio}, issn = {0745-2993}, pages = {56}, year = {2013}, language = {en} } @article{KraffWredeSchoembergetal.2013, author = {Kraff, Oliver and Wrede, Karsten H. and Schoemberg, Tobias and Dammann, Philipp and Noureddine, Yacine and Orzada, Stephan and Ladd, Mark E. and Bitz, Andreas}, title = {MR safety assessment of potential RF heating from cranial fixation plates at 7 T}, series = {Medical Physics}, volume = {40}, journal = {Medical Physics}, number = {4}, publisher = {Wiley}, address = {Hoboken}, issn = {2473-4209}, doi = {10.1118/1.4795347}, pages = {042302-1 -- 042302-10}, year = {2013}, language = {en} } @article{UmutluMaderwaldKinneretal.2013, author = {Umutlu, L. and Maderwald, S. and Kinner, S. and Kraff, O. and Bitz, Andreas and Orzada, S. and Johst, S. and Wrede, K. and Forsting, M. and Ladd, M. E. and Lauenstein, T. C. and Quick, H. H.}, title = {First-pass contrast-enhanced renal MRA at 7 Tesla: initial results}, series = {European Radiology}, volume = {23}, journal = {European Radiology}, number = {4}, publisher = {Springer}, address = {Berlin}, issn = {1432-1084}, doi = {10.1007/s00330-012-2666-0}, pages = {1059 -- 1066}, year = {2013}, language = {en} } @article{UmutluOrzadaKinneretal.2011, author = {Umutlu, Lale and Orzada, Stephan and Kinner, Sonja and Maderwald, Stefan and Bronte, Irina and Bitz, Andreas and Kraff, Oliver and Ladd, Susanne C. and Antoch, Gerald and Ladd, Mark E. and Quick, Harald H. and Lauenstein, Thomas C.}, title = {Renal imaging at 7 Tesla: preliminary results}, series = {European Radiology}, volume = {21}, journal = {European Radiology}, number = {4}, publisher = {Springer}, address = {Berlin}, issn = {1432-1084}, pages = {841 -- 849}, year = {2011}, abstract = {Objective To investigate the feasibility of 7T MR imaging of the kidneys utilising a custom-built 8-channel transmit/receive radiofrequency body coil. Methods In vivo unenhanced MR was performed in 8 healthy volunteers on a 7T whole-body MR system. After B0 shimming the following sequences were obtained: 1) 2D and 3D spoiled gradient-echo sequences (FLASH, VIBE), 2) T1-weighted 2D in and opposed phase 3) True-FISP imaging and 4) a T2-weighted turbo spin echo (TSE) sequence. Visual evaluation of the overall image quality was performed by two radiologists. Results Renal MRI at 7T was feasible in all eight subjects. Best image quality was found using T1-weighted gradient echo MRI, providing high anatomical details and excellent conspicuity of the non-enhanced vasculature. With successful shimming, B1 signal voids could be effectively reduced and/or shifted out of the region of interest in most sequence types. However, T2-weighted TSE imaging remained challenging and strongly impaired because of signal heterogeneities in three volunteers. Conclusion The results demonstrate the feasibility and diagnostic potential of dedicated 7T renal imaging. Further optimisation of imaging sequences and dedicated RF coil concepts are expected to improve the acquisition quality and ultimately provide high clinical diagnostic value.}, language = {en} } @article{HueningHeuermannWacheetal.2018, author = {H{\"u}ning, Felix and Heuermann, Holger and Wache, Franz-Josef and Jajo, Rami Audisho}, title = {A new wireless sensor interface using dual-mode radio}, series = {Journal of Sensors and Sensor Systems : JSSS}, volume = {Volume 7}, journal = {Journal of Sensors and Sensor Systems : JSSS}, number = {2}, publisher = {Copernicus Publ.}, address = {G{\"o}ttingen}, doi = {10.5194/jsss-7-507-2018}, pages = {507 -- 515}, year = {2018}, abstract = {The integration of sensors is one of the major tasks in embedded, control and "internet of things" (IoT) applications. For the integration mainly digital interfaces are used, starting from rather simple pulse-width modulation (PWM) interface to more complex interfaces like CAN (Controller Area Network). Even though these interfaces are tethered by definition, a wireless realization is highly welcome in many applications to reduce cable and connector cost, increase the flexibility and realize new emerging applications like wireless control systems. Currently used wireless solutions like Bluetooth, WirelessHART or IO-Link Wireless use dedicated communication standards and corresponding higher protocol layers to realize the wireless communication. Due to the complexity of the communication and the protocol handling, additional latency and jitter are introduced to the data communication that can meet the requirements for many applications. Even though tunnelling of other bus data like CAN data is generally also possible the latency and jitter prevent the tunnelling from being transparent for the bus system. Therefore a new basic technology based on dual-mode radio is used to realize a wireless communication on the physical layer only, enabling a reliable and real-time data transfer. As this system operates on the physical layer it is independent of any higher layers of the OSI (open systems interconnection) model. Hence it can be used for several different communication systems to replace the tethered physical layer. A prototype is developed and tested for real-time wireless PWM, SENT (single-edge nibble transmission) and CAN data transfer with very low latency and jitter.}, language = {en} } @inproceedings{AlhwarinFerreinScholl2018, author = {Alhwarin, Faraj and Ferrein, Alexander and Scholl, Ingrid}, title = {CRVM: Circular Random Variable-based Matcher - A Novel Hashing Method for Fast NN Search in High-dimensional Spaces}, series = {Proceedings of the 7th International Conference on Pattern Recognition Applications and Methods, ICPRAM 2018}, booktitle = {Proceedings of the 7th International Conference on Pattern Recognition Applications and Methods, ICPRAM 2018}, isbn = {978-989-758-276-9}, doi = {10.5220/0006692802140221}, pages = {214 -- 221}, year = {2018}, language = {en} } @inproceedings{AlhwarinSchifferFerreinetal.2018, author = {Alhwarin, Faraj and Schiffer, Stefan and Ferrein, Alexander and Scholl, Ingrid}, title = {Optimized KinectFusion Algorithm for 3D Scanning Applications}, series = {Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies - Volume 2: BIOIMAGING}, booktitle = {Proceedings of the 11th International Joint Conference on Biomedical Engineering Systems and Technologies - Volume 2: BIOIMAGING}, isbn = {978-989-758-278-3}, doi = {10.5220/0006594700500057}, pages = {50 -- 57}, year = {2018}, language = {en} } @inproceedings{HofmannMatareSchifferetal.2018, author = {Hofmann, Till and Matar{\´e}, Victor and Schiffer, Stefan and Ferrein, Alexander and Lakemeyer, Gerhard}, title = {Constraint-based online transformation of abstract plans into executable robot actions}, series = {Proceedings of the 2018 AAAI Spring Symposium on Integrating Representation, Reasoning, Learning, and Execution for Goal Directed Autonomy}, booktitle = {Proceedings of the 2018 AAAI Spring Symposium on Integrating Representation, Reasoning, Learning, and Execution for Goal Directed Autonomy}, pages = {549 -- 553}, year = {2018}, language = {en} } @inproceedings{FerreinSchifferKallweit2018, author = {Ferrein, Alexander and Schiffer, Stefan and Kallweit, Stephan}, title = {The ROSIN Education Concept - Fostering ROS Industrial-Related Robotics Education in Europe}, series = {ROBOT 2017: Third Iberian Robotics Conference}, booktitle = {ROBOT 2017: Third Iberian Robotics Conference}, publisher = {Springer}, address = {Cham}, isbn = {978-3-319-70836-2}, doi = {10.1007/978-3-319-70836-2_31}, pages = {370 -- 381}, year = {2018}, language = {en} } @inproceedings{HofmannMatareNeumannetal.2018, author = {Hofmann, Till and Matar{\´e}, Victor and Neumann, Tobias and Sch{\"o}nitz, Sebastian and Henke, Christoph and Limpert, Nicolas and Niemueller, Tim and Ferrein, Alexander and Jeschke, Sabina and Lakemeyer, Gerhard}, title = {Enhancing Software and Hardware Reliability for a Successful Participation in the RoboCup Logistics League 2017}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-00308-1}, doi = {10.1007/978-3-030-00308-1_40}, pages = {486 -- 497}, year = {2018}, language = {en} } @article{SchifferFerrein2018, author = {Schiffer, Stefan and Ferrein, Alexander}, title = {ERIKA—Early Robotics Introduction at Kindergarten Age}, series = {Multimodal Technologies Interact}, volume = {2}, journal = {Multimodal Technologies Interact}, number = {4}, publisher = {MDPI}, address = {Basel}, issn = {2414-4088}, doi = {10.3390/mti2040064}, pages = {15}, year = {2018}, abstract = {In this work, we report on our attempt to design and implement an early introduction to basic robotics principles for children at kindergarten age. One of the main challenges of this effort is to explain complex robotics contents in a way that pre-school children could follow the basic principles and ideas using examples from their world of experience. What sets apart our effort from other work is that part of the lecturing is actually done by a robot itself and that a quiz at the end of the lesson is done using robots as well. The humanoid robot Pepper from Softbank, which is a great platform for human-robot interaction experiments, was used to present a lecture on robotics by reading out the contents to the children making use of its speech synthesis capability. A quiz in a Runaround-game-show style after the lecture activated the children to recap the contents they acquired about how mobile robots work in principle. In this quiz, two LEGO Mindstorm EV3 robots were used to implement a strongly interactive scenario. Besides the thrill of being exposed to a mobile robot that would also react to the children, they were very excited and at the same time very concentrated. We got very positive feedback from the children as well as from their educators. To the best of our knowledge, this is one of only few attempts to use a robot like Pepper not as a tele-teaching tool, but as the teacher itself in order to engage pre-school children with complex robotics contents.}, language = {en} } @article{HueningHeuermannWache2018, author = {H{\"u}ning, Felix and Heuermann, Holger and Wache, Franz-Josef}, title = {Wireless CAN}, series = {Etz: Elektrotechnik \& Automation}, volume = {139}, journal = {Etz: Elektrotechnik \& Automation}, number = {10}, publisher = {VDE-Verlag}, address = {Wuppertal}, issn = {0170-1711}, pages = {22 -- 26}, year = {2018}, abstract = {In modernen elektronischen und mechatronischen Systemen, z. B. im industriellen oder automobil Bereich, kommunizieren eingebettete Steuerger{\"a}te und Sensoren vielfach {\"u}ber Bussysteme wie CAN oder LIN. Die Kommunikation findet in der Regel drahtgebunden statt, so dass der Kabelbaum f{\"u}r die Kommunikation sehr groß werden kann. Daher ist es naheliegend, Leitungen und dazugeh{\"o}rige Stecker, z. B. f{\"u}r nicht-sicherheitskritische Komfortsysteme, einzusparen und diese durch gerichtete Funkstrecken f{\"u}r kurze Entfernungen zu ersetzen. Somit k{\"o}nnten Komponenten wie ECUs oder Sensoren kabel- und steckerlos in ein Bussystem integriert werden. Zudem ist eine einfache galvanische und mechanische Trennung zu erreichen. Funk{\"u}bertragung wird bei diesen Bussystemen derzeit nicht eingesetzt, da insbesondere die Echtzeitf{\"a}higkeit und die Robustheit der vorhandenen Funksysteme nicht den Anforderungen der Anwendungen entspricht. Zudem sind bestehende Funksysteme wie WLAN oder Bluetooth im Vergleich zur konventionellen Verkabelung teuer und es besteht hierbei die M{\"o}glichkeit, dass sie ausspioniert werden k{\"o}nnen und so sensible Daten entwendet werden k{\"o}nnen. In dieser Arbeit wird eine alternative Realisierung zu den bestehenden Funksystemen vorgestellt, die aus wenigen Komponenten aufzubauen ist. Es ist eine protokolllose, echtzeitf{\"a}hige {\"U}bertragung m{\"o}glich und somit die transparente Integration in ein Bussystem wie CAN.}, language = {de} } @article{Huening2019, author = {H{\"u}ning, Felix}, title = {Nachr{\"u}stm{\"o}glichkeiten von Dieselfahrzeugen aus technischer Sicht}, series = {Zeitschrift f{\"u}r Verkehrsrecht : NZV}, journal = {Zeitschrift f{\"u}r Verkehrsrecht : NZV}, number = {1}, publisher = {C.H.Beck}, pages = {27 -- 32}, year = {2019}, language = {de} } @inproceedings{EssingholtMeyerKuhnetal.2018, author = {Essingholt, Felix and Meyer, Frederic and Kuhn, Peter and Schmidt, Philip and Benkner, Thorsten and Grabmaier, Anton}, title = {Non-invasive heart beat measurement using microwave resonators}, series = {Proceedings, Vol. 2, Eurosensors 2018 Conference, Graz, Austria, 9-12 September 2018}, booktitle = {Proceedings, Vol. 2, Eurosensors 2018 Conference, Graz, Austria, 9-12 September 2018}, publisher = {MDPI}, address = {Basel}, issn = {2504-3900}, doi = {10.3390/proceedings2131002}, pages = {1002}, year = {2018}, language = {en} } @article{HueningHeuermannWache2018, author = {H{\"u}ning, Felix and Heuermann, Holger and Wache, Franz-Josef}, title = {Wireless CAN without WLAN or Bluetooth}, series = {CAN Newsletter}, journal = {CAN Newsletter}, number = {December 2018}, pages = {44 -- 46}, year = {2018}, abstract = {In two developed concepts, dual-mode radio enables CAN participants to be integrated wirelessly into a CAN network. Constructed from a few components, a protocol-free, real-time transmission and thus transparent integration into CAN is provided.}, language = {en} } @inproceedings{HeuermannHarzheimMuehmel2021, author = {Heuermann, Holger and Harzheim, Thomas and M{\"u}hmel, Marc}, title = {A maritime harmonic radar search and rescue system using passive and active tags}, series = {2020 17th European Radar Conference (EuRAD)}, booktitle = {2020 17th European Radar Conference (EuRAD)}, publisher = {IEEE}, address = {New York, NY}, isbn = {978-2-87487-061-3}, doi = {10.1109/EuRAD48048.2021.00030}, pages = {73 -- 76}, year = {2021}, abstract = {This article 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 attached to life jackets and a rescue boat. This system was able to detect and range the active tags up to a range of 5800 m in tests on the Baltic Sea with an antenna input power of only 100 W. All electronic GHz components of the system, excluding the S-band power amplifier, were custom developed for this purpose. Special attention is given to the performance and conceptual differences between passive and active tags used in the system and integration with a maritime X-band navigation radar is demonstrated.}, language = {en} } @techreport{JaekelKleinBarthetal.1996, author = {Jaekel, C. and Klein, C. and Barth, R. and Roskos, H. and Kyas, G. and Schroeer, M. and H{\"u}ning, Felix}, title = {Dynamik von Nichtgleichgewichtszustaenden in Hochtemperatursupraleitern Abschlussbericht}, pages = {47 Seiten}, year = {1996}, abstract = {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.}, language = {de} } @inproceedings{FerreinMeessenLimpertetal.2021, author = {Ferrein, Alexander and Meeßen, Marcus and Limpert, Nicolas and Schiffer, Stefan}, title = {Compiling ROS schooling curricula via contentual taxonomies}, series = {Robotics in Education}, booktitle = {Robotics in Education}, editor = {Lepuschitz, Wilfried}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-67411-3}, doi = {10.1007/978-3-030-67411-3_5}, pages = {49 -- 60}, year = {2021}, abstract = {The Robot Operating System (ROS) is the current de-facto standard in robot middlewares. The steadily increasing size of the user base results in a greater demand for training as well. User groups range from students in academia to industry professionals with a broad spectrum of developers in between. To deliver high quality training and education to any of these audiences, educators need to tailor individual curricula for any such training. In this paper, we present an approach to ease compiling curricula for ROS trainings based on a taxonomy of the teaching contents. The instructor can select a set of dedicated learning units and the system will automatically compile the teaching material based on the dependencies of the units selected and a set of parameters for a particular training. We walk through an example training to illustrate our work.}, language = {en} } @article{RoepkeKoehlerDruryetal.2020, author = {Roepke, Rene and K{\"o}hler, Klemens and Drury, Vincent and Schroeder, Ulrik and Wolf, Martin and Meyer, Ulrike}, title = {A pond full of phishing games - analysis of learning games for anti-phishing education}, series = {Model-driven Simulation and Training Environments for Cybersecurity. MSTEC 2020}, journal = {Model-driven Simulation and Training Environments for Cybersecurity. MSTEC 2020}, publisher = {Springer}, address = {Cham}, isbn = {978-3-030-62433-0}, doi = {10.1007/978-3-030-62433-0_32020}, pages = {41 -- 60}, year = {2020}, abstract = {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.}, language = {en} } @inproceedings{HoegenDonckerRuetters2020, author = {Hoegen, Anne von and Doncker, Rik W. De and R{\"u}tters, Ren{\´e}}, title = {Teaching Digital Control of Operational Amplifier Processes with a LabVIEW Interface and Embedded Hardware}, series = {2020 23rd International Conference on Electrical Machines and Systems (ICEMS)}, booktitle = {2020 23rd International Conference on Electrical Machines and Systems (ICEMS)}, publisher = {IEEE}, address = {New York, NY}, doi = {10.23919/ICEMS50442.2020.9290928}, pages = {1117 -- 1122}, year = {2020}, abstract = {Control engineering theory is hard to grasp for undergraduates during the first semesters, as it deals with the dynamical behavior of systems also in combination with control strategies on an abstract level. Therefore, operational amplifier (OpAmp) processes are reasonable and very effective systems to connect mathematical description with actual system's behavior. In this paper, we present an experiment for a laboratory session in which an embedded system, driven by a LabVIEW human machine interface (HMI) via USB, controls the analog circuits.With this setup we want to show the possibility of firstly, analyzing a first order process and secondly, designing a P-and PI-controller. Thereby, the theory of control engineering is always applied to the empirical results in order to break down the abstract level for the students.}, language = {en} } @incollection{SchubaHoefken2022, author = {Schuba, Marko and H{\"o}fken, Hans-Wilhelm}, title = {Cybersicherheit in Produktion, Automotive und intelligenten Geb{\"a}uden}, series = {IT-Sicherheit - Technologien und Best Practices f{\"u}r die Umsetzung im Unternehmen}, booktitle = {IT-Sicherheit - Technologien und Best Practices f{\"u}r die Umsetzung im Unternehmen}, publisher = {Carl Hanser Verlag}, address = {M{\"u}nchen}, isbn = {978-3-446-47223-5}, doi = {10.3139/9783446473478.012}, pages = {193 -- 218}, year = {2022}, language = {de} } @incollection{EnglaenderKaminskiSchuba2022, author = {Engl{\"a}nder, Jacques and Kaminski, Lars and Schuba, Marko}, title = {Informationssicherheitsmanagement}, series = {Digitalisierungs- und Informationsmanagement}, booktitle = {Digitalisierungs- und Informationsmanagement}, publisher = {Springer Vieweg}, address = {Berlin}, isbn = {978-3-662-63757-9}, doi = {10.1007/978-3-662-63758-6_15}, pages = {373 -- 398}, year = {2022}, abstract = {Daten und Informationen sind die wichtigsten Ressourcen vieler Unternehmen und m{\"u}ssen daher entsprechend gesch{\"u}tzt werden. Getrieben durch die erh{\"o}hte Vernetzung von Informationstechnologie, die h{\"o}here Offenheit infolge datengetriebener Dienstleistungen und eine starke Zunahme an Datenquellen, r{\"u}cken die Gefahren von Informationsdiebstahl, -manipulation und -verlust in den Fokus von produzierenden Unternehmen. Auf dem Weg zum lern- und wandlungsf{\"a}higen Unternehmen kann dies zu einem großen Hindernis werden, da einerseits zu hohe Sicherheitsanforderungen neue Entwicklungen beschr{\"a}nken, andererseits wegen des Mangels an ausreichenden Informationssicherheitskonzepten Unternehmen weniger Innovationen wagen. Deshalb bedarf es individuell angepasster Konzepte f{\"u}r die Bereiche IT-Security, IT-Safety und Datenschutz f{\"u}r vernetzte Produkte, Produktion und Arbeitspl{\"a}tze. Bei der Entwicklung und Durchsetzung dieser Konzepte steht der Faktor Mensch im Zentrum aller {\"U}berlegungen. In diesem Kapitel wird dargestellt, wie der Faktor Mensch bei der Erstellung von Informationssicherheitskonzepten in verschiedenen Phasen zu beachten ist. Beginnend mit der Integration von Informationssystemen und damit verbundenen Sicherheitsmaßnahmen, {\"u}ber die Administration, bis hin zur Anwendung durch den Endnutzer, werden Methoden beschrieben, die den Menschen, verbunden mit seinem Mehrwert wie auch den Risiken, einschließen. Dabei werden sowohl Grundlagen aufgezeigt als auch Konzepte vorgestellt, mit denen Entscheider in der Unternehmens-IT Leitlinien f{\"u}r die Informationssicherheit festlegen k{\"o}nnen.}, language = {de} } @inproceedings{SchubaHoefkenLinzbach2022, author = {Schuba, Marko and H{\"o}fken, Hans-Wilhelm and Linzbach, Sophie}, title = {An ICS Honeynet for Detecting and Analyzing Cyberattacks in Industrial Plants}, series = {2021 International Conference on Electrical, Computer and Energy Technologies (ICECET)}, booktitle = {2021 International Conference on Electrical, Computer and Energy Technologies (ICECET)}, publisher = {IEEE}, isbn = {978-1-6654-4231-2}, doi = {10.1109/ICECET52533.2021.9698746}, pages = {6 Seiten}, year = {2022}, abstract = {Cybersecurity of Industrial Control Systems (ICS) is an important issue, as ICS incidents may have a direct impact on safety of people or the environment. At the same time the awareness and knowledge about cybersecurity, particularly in the context of ICS, is alarmingly low. Industrial honeypots offer a cheap and easy to implement way to raise cybersecurity awareness and to educate ICS staff about typical attack patterns. When integrated in a productive network, industrial honeypots may not only reveal attackers early but may also distract them from the actual important systems of the network. Implementing multiple honeypots as a honeynet, the systems can be used to emulate or simulate a whole Industrial Control System. This paper describes a network of honeypots emulating HTTP, SNMP, S7communication and the Modbus protocol using Conpot, IMUNES and SNAP7. The nodes mimic SIMATIC S7 programmable logic controllers (PLCs) which are widely used across the globe. The deployed honeypots' features will be compared with the features of real SIMATIC S7 PLCs. Furthermore, the honeynet has been made publicly available for ten days and occurring cyberattacks have been analyzed}, language = {en} } @inproceedings{ChristianMontagSchubaetal.2018, author = {Christian, Esser and Montag, Tim and Schuba, Marko and Allhof, Manuel}, title = {Future critical infrastructure and security - cyberattacks on charging stations}, series = {31st International Electric Vehicle Symposium \& Exhibition and International Electric Vehicle Technology Conference (EVS31 \& EVTeC 2018)}, booktitle = {31st International Electric Vehicle Symposium \& Exhibition and International Electric Vehicle Technology Conference (EVS31 \& EVTeC 2018)}, publisher = {Society of Automotive Engineers of Japan (JSAE)}, address = {Tokyo}, isbn = {978-1-5108-9157-9}, pages = {665 -- 671}, year = {2018}, language = {en} } @inproceedings{MaikeLenzWolf2014, author = {Maike, M{\"u}ller and Lenz, Laura and Wolf, Martin}, title = {Steigerung der Effektivit{\"a}t durch Prozessmodellierungs-Tools - {\"A}nderbarkeit und Transparenz von Prozessen am Beispiel der Business Simulation Apollo 13}, series = {Informatik 2014}, booktitle = {Informatik 2014}, publisher = {Gesellschaft f{\"u}r Informatik e.V.}, address = {Bonn}, isbn = {978-3-88579-626-8}, issn = {1617-5468}, pages = {357 -- 369}, year = {2014}, abstract = {Die Nutzung von Prozessmodellierungsmethoden oder - werkzeugen kann erheblichen Einfluss auf die Effektivit{\"a}t von Prozessen haben. Das gilt insbesondere f{\"u}r Situationen, in denen Personen unter Stress stehen oder unge{\"u}bt sind. In diesen F{\"a}llen geben Prozessmodelle konkrete Empfehlungen, nach denen sich die handelnden Personen richten k{\"o}nnten. In Experimenten mit der Business-Simulation Apollo 13 haben wir den Effekt eines Einsatzes von Prozessmodellierungsmethoden und -werkzeugen untersucht. Bereits bekannte Theorien (z.B. {\"u}ber geeignete Verh{\"a}ltnisse von Kommunikationsinhalten) konnten best{\"a}tigt werden. Dar{\"u}ber hinaus haben wir eine besondere Bedeutung der {\"U}bertragbarkeit von Prozessmodellen in konkrete Handlungen identifiziert.}, language = {de} } @techreport{ThomaLaarmannMerkensetal.2020, author = {Thoma, Andreas and Laarmann, Lukas and Merkens, Torsten and Franzke, Till and M{\"o}hren, Felix and Buttermann, Lilly and van der Weem, Dirk and Fischer, Maximilian and Misch, Philipp and B{\"o}hme, Mirijam and R{\"o}th, Thilo and Hebel, Christoph and Ritz, Thomas and Franke, Marina and Braun, Carsten}, title = {Entwicklung eines intermodalen Mobilit{\"a}tskonzeptes f{\"u}r die Pilotregion NRW/Rhein-Maas Euregio und Schaffung voller Kundenakzeptanz durch Transfer von Standards aus dem PKW-Bereich auf ein Flugtaxi : Schlussbericht : Projektakronym: SkyCab (Kategorie B) : Laufzeit in Monaten: 6 : Hauptthema: Kategorie B: Innovative Ideen mit Bezug zu UAS/Flugtaxis}, publisher = {FH Aachen}, address = {Aachen}, pages = {97 Seiten}, year = {2020}, language = {de} } @article{Wolf2000, author = {Wolf, Martin}, title = {Groupware related task design}, series = {ACM SIGGROUP Bulletin}, volume = {21}, journal = {ACM SIGGROUP Bulletin}, number = {2}, issn = {2372-7403}, doi = {10.1145/605660.605662}, pages = {5 -- 8}, year = {2000}, abstract = {his report summarizes the results of a workshop on Groupware related task design which took place at the International Conference on Supporting Group Work Group'99, Arizona, from 14 th to 17 th November 1999. The workshop was addressed to people from different viewpoints, backgrounds, and domains: - Researchers dealing with questions of task analysis and task modeling for Groupware application from an academic point of view. They may contribute modelbased design approaches or theoretically oriented work - Practitioners with experience in the design and everyday use of groupware systems. They might refer to the practical side of the topic: "real" tasks, "real" problems, "real" users, etc.}, language = {en} } @inproceedings{KoenigVoelkerWolf2018, author = {K{\"o}nig, Johannes Alexander and V{\"o}lker, Veronika and Wolf, Martin}, title = {The user-focused storybuilding framework for competence developing games - a design-framework considering the basics of an educational game's story}, series = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, booktitle = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, isbn = {978-1-61208-616-3}, pages = {98 -- 106}, year = {2018}, abstract = {During the development of a Competence Developing Game's (CDG) story it is indispensable to understand the target audience. Thereby, CDGs stories represent more than just the plot. The Story is about the Setting, the Characters and the Plot. As a toolkit to support the development of such a story, this paper introduces the UserFocused Storybuilding (short UFoS) Framework for CDGs. The Framework and its utilization will be explained, followed by a description of its development and derivation, including an empirical study. In addition, to simplify the Framework use regarding the CDG's target audience, a new concept of Nine Psychographic Player Types will be explained. This concept of Player Types provides an approach to handle the differences in between players during the UFoS Framework use. Thereby, this article presents a unique approach to the development of target group-differentiated CDGs stories.}, language = {en} } @inproceedings{DowidatKoenigWolf2017, author = {Dowidat, Linda and K{\"o}nig, Johannes Alexander and Wolf, Martin}, title = {The motivational competence developing game framework}, series = {Mensch und Computer 2017 - Tagungsband}, booktitle = {Mensch und Computer 2017 - Tagungsband}, publisher = {Gesellschaft f{\"u}r Informatik e.V.}, address = {Regensburg}, doi = {10.18420/muc2017-mci-0130}, pages = {15 -- 26}, year = {2017}, abstract = {Competence Developing Games (CDGs) are a new concept of how to think about games with serious intentions. In order to emphasize on this topic, a new framework has been developed. It basically relies on learning and motivation theories. This 'motivational Competence Developing Game Framework' demonstrates how it is possible to use these theories in a CDG development process. The theoretical derivation and use of the framework is explained in this paper.}, language = {en} } @inproceedings{KoenigWolf2018, author = {K{\"o}nig, Johannes Alexander and Wolf, Martin}, title = {Cybersecurity awareness training provided by the competence developing game GHOST}, series = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, booktitle = {ACHI 2018 : The Eleventh International Conference on Advances in Computer-Human Interactions}, isbn = {978-1-61208-616-3}, pages = {81 -- 87}, year = {2018}, abstract = {This paper introduces a Competence Developing Game (CDG) for the purpose of a cybersecurity awareness training for businesses. The target audience will be discussed in detail to understand their requirements. It will be explained why and how a mix of business simulation and serious game meets these stakeholder requirements. It will be shown that a tablet and touchscreen based approach is the most suitable solution. In addition, an empirical study will be briefly presented. The study was carried out to examine how an interaction system for a 3D-tablet based CDG has to be designed, to be manageable for non-game experienced employees. Furthermore, it will be explained which serious content is necessary for a Cybersecurity awareness training CDG and how this content is wrapped in the game}, language = {en} } @article{HeuermannEmmrichBongartz2022, author = {Heuermann, Holger and Emmrich, Thomas and Bongartz, Simon}, title = {Microwave spark plug to support ignitions with high compression ratios}, series = {IEEE Transactions on Plasma Science}, journal = {IEEE Transactions on Plasma Science}, number = {Early Access}, publisher = {IEEE}, issn = {1939-9375}, doi = {10.1109/TPS.2022.3183690}, pages = {1 -- 6}, year = {2022}, abstract = {Upcoming gasoline engines should run with a larger number of fuels beginning from petrol over methanol up to gas by a wide range of compression ratios and a homogeneous charge. In this article, the microwave (MW) spark plug, based on a high-speed frequency hopping system, is introduced as a solution, which can support a nitrogen compression ratio up to 1:39 in a chamber and more. First, an overview of the high-speed frequency hopping MW ignition and operation system as well as the large number of applications are presented. Both gives an understanding of this new base technology for MW plasma generation. Focus of the theoretical part is the explanation of the internal construction of the spark plug, on the achievable of the high voltage generation as well as the high efficiency to hold the plasma. In detail, the development process starting with circuit simulations and ending with the numerical multiphysics field simulations is described. The concept is evaluated with a reference prototype covering the frequency range between 2.40 and 2.48 GHz and working over a large power range from 20 to 200 W. A larger number of different measurements starting by vector hot-S11 measurements and ending by combined working scenarios out of hot temperature, high pressure and charge motion are winding up the article. The limits for the successful pressure tests were given by the pressure chamber. Pressures ranged from 1 to 39 bar and charge motion up to 25 m/s as well as temperatures from 30◦ to 125◦.}, language = {en} } @inproceedings{NeesStengelMeisteretal.2020, author = {Nees, Franz and Stengel, Ingo and Meister, Vera G. and Barton, Thomas and Herrmann, Frank and M{\"u}ller, Christian and Wolf, Martin}, title = {Angewandte Forschung in der Wirtschaftsinformatik 2020 : Tagungsband zur 33. AKWI-Jahrestagung am 14.09.2020, ausgerichtet von der Hochschule Karlsruhe - Wirtschaft und Technik / hrsg. von Franz Nees, Ingo Stengel, Vera G. Meister, Thomas Barton, Frank Herrmann, Christian M{\"u}ller, Martin R. Wolf}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-66-2}, doi = {10.15771/978-3-944330-66-2}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13840}, pages = {147 Seiten}, year = {2020}, abstract = {Tagungsbeitr{\"a}ge aus den Bereichen KI, Prozessorganisation und Plattformen f{\"u}r Gesch{\"a}ftsprozesse, Sicherheit und Datenschutz sowie Prototypen und Modelle.}, language = {de} } @inproceedings{WolfBartonHerrmannetal.2019, author = {Wolf, Martin and Barton, Thomas and Herrmann, Frank and Meister, Vera G. and M{\"u}ller, Christian and Seel, Christian}, title = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung vom 15.09.2019 bis 18.09.2019 an der Fachhochschule f{\"u}r Angewandte Wissenschaften Aachen / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian M{\"u}ller, Christian Seel}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-62-4}, doi = {10.15771/978-3-944330-62-4}, url = {http://nbn-resolving.de/urn:nbn:de:kobv:526-opus4-13026}, pages = {261 Seiten}, year = {2019}, abstract = {Tagungsbeitr{\"a}ge aus den Bereichen Projektmanagement, Didaktik in der Wirtschaftsinformatik, IT-Sicherheit, Anwendungsf{\"a}lle, Reifegradmodelle, Plattformen f{\"u}r Gesch{\"a}ftsprozesse und Prototypen.}, language = {de} } @inproceedings{MollKoehlerWolf2019, author = {Moll, Florian and K{\"o}hler, Klemens and Wolf, Martin}, title = {Konzeption von IT-Sicherheitsl{\"o}sungen unter ethischen Gesichtspunkten am Beispiel einer Monitoring-App f{\"u}r mobile Endger{\"a}te}, series = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung}, booktitle = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-62-4}, pages = {61 -- 72}, year = {2019}, abstract = {Die steigende Popularit{\"a}t von mobilen Endger{\"a}ten im privaten und gesch{\"a}ftlichen Umfeld geht mit einem Anstieg an Sicherheitsl{\"u}cken und somit potentiellen Angriffsfl{\"a}chen einher. Als ein Element der technischen und organisatorischen Maßnahmen zum Schutz eines Netzwerkes k{\"o}nnen Monitoring-Apps dienen, die unerw{\"u}nschtes Verhalten und Angriffe erkennen. Die automatisierte {\"U}berwachung von Endger{\"a}ten ist jedoch rechtlich und ethisch komplex. Dies in Kombination mit einer hohen Sensibilit{\"a}t der Nutzer und Nutzerinnen dieser Ger{\"a}te in Bezug auf Privatsph{\"a}re, kann zu einer geringen Akzeptanz und Compliance f{\"u}hren. Eine datenschutzrechtlich und ethisch einwandfreie Konzeption solcher Apps bereits im Designprozess f{\"u}hrt zu h{\"o}herer Akzeptanz und verbessert so die Effizienz. Diese Analyse beschreibt M{\"o}glichkeiten zur Umsetzung.}, language = {de} } @inproceedings{BeckerWolf2019, author = {Becker, Willi and Wolf, Martin}, title = {Entwicklung eines Einf{\"u}hrungskonzepts f{\"u}r IT-Service-Management in KMU}, series = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian M{\"u}ller, Christian Seel}, booktitle = {Angewandte Forschung in der Wirtschaftsinformatik 2019 : Tagungsband zur 32. AKWI-Jahrestagung / hrsg. von Martin R. Wolf, Thomas Barton, Frank Herrmann, Vera G. Meister, Christian M{\"u}ller, Christian Seel}, publisher = {mana-Buch}, address = {Heide}, isbn = {978-3-944330-62-4}, pages = {129 -- 137}, year = {2019}, abstract = {Obwohl es eine Vielzahl von Einf{\"u}hrungskonzepten f{\"u}r ITSM gibt, hat sich bisher keines dieser Konzepte auf breiter Linie durchgesetzt. Das gilt in erh{\"o}htem Maße f{\"u}r ITSM-Einf{\"u}hrungskonzepte f{\"u}r KMU, wohl nicht zuletzt aufgrund der Tatsache, dass der Mehrwert von ITSM f{\"u}r KMU aufgrund der geringeren Gr{\"o}ße der IT-Organisationen nur entsprechend schwieriger generiert werden kann. Mit diesem Beitrag wird ein Einf{\"u}hrungskonzept f{\"u}r ITSM in KMU systematisch hergeleitet. Daf{\"u}r wurden zun{\"a}chst die Treiber und Barrieren von ITSM untersucht, um daraus ein umfassendes Wirkmodell zu entwickeln. Da mit diesem Wirkungsmodell die Einflussfaktoren auf den Erfolg von ITSM in KMU deutlich werden, konnte auf dieser Basis ein Einf{\"u}hrungskonzept abgeleitet werden, welches insbesondere die positiven Effekte unterst{\"u}tzt bzw. verst{\"a}rkt.}, language = {de} }