TY - JOUR A1 - Zastrow, Udo T1 - Solution of plane anisotropic elastostatical boundary value problems by singular integral equations JF - Acta Mechanica. 44 (1982), H. 1-2 Y1 - 1982 SN - 1619-6937 SP - 59 EP - 71 ER - TY - JOUR A1 - Yazdanbakhsh, Pedram A1 - Solbach, Klaus A1 - Bitz, Andreas T1 - Variable power combiner for RF mode shimming in 7-T MR imaging JF - IEEE Transaction on Biomedical Engineering N2 - 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. Y1 - 2012 U6 - http://dx.doi.org/10.1109/TBME.2012.2205926 SN - 1558-2531 VL - 59 IS - 9 SP - 2549 EP - 2557 PB - IEEE CY - New York ER - TY - CHAP A1 - Xu, Zhanping A1 - Schwarte, Rudolf A1 - Heinol, Horst-Guenther A1 - Buxbaum, Bernd A1 - Ringbeck, Thorsten ED - Cheung, Edmund H. M. T1 - Smart pixel : photonic mixer device (PMD) ; new system concept of a 3D-imaging camera-on-a-chip T2 - Proceedings : M2VIP '98; Nanjing, China, 10th - 12th September 1998 Y1 - 1998 SN - 962-442-129-3 N1 - International Conference on Mechatronics and Machine Vision in Practice <5, 1998, Nanking> ; M2VIP <5, 1998, Nanking> SP - 259 EP - 264 CY - Hong Kong ER - TY - BOOK A1 - Wosnitza, Franz A1 - Hilgers, Hans Gerd T1 - Energieeffizienz und Energiemanagement : ein Überblick heutiger Möglichkeiten und Notwendigkeiten Y1 - 2012 SN - 978-3-8348-1941-3 N1 - eISBN 978-3-8348-8671-2 PB - Springer Spektrum CY - Wiesbaden ER - TY - CHAP A1 - Wolf, Martin A1 - Wiese, Ute T1 - A comparative transformation model for process changes using serious games T2 - 2013 IEEE 2nd International Conference on Serious Games and Applications for Health (SeGAH): proceedings of a meeting held 2-3 May 2013, Algarve, Portugal Y1 - 2013 SN - 978-1-4673-6164-4 U6 - http://dx.doi.org/10.1109/SeGAH.2013.6665307 SP - 64 EP - 70 PB - Institute of Electrical and Electronics Engineers (IEEE) CY - Piscataway, NJ ER - TY - JOUR A1 - Wolf, Martin A1 - Simon, S. A1 - Schlick, Christopher T1 - Qualitative and Quantitative Analysis of Cooperation / Wolf, M. ; Simon, S. ; Schlick, C. JF - Proceedings : May 26 - 29, 1998, Cannes (France) = Actes : 26 - 29 mai 1998 / INRIA, Institut National de Recherche en Informatique et en Automatique, Unité de recherche ... F. Darses ..., eds Y1 - 1998 N1 - COOP ; Institut National de Recherche en Informatique et en Automatique ; Centre ; (Sophia Antipolis) ; International Conference on the Design of Cooperative Systems ; (3 ; 1998.05.26-29 ; Cannes) ; Conference Internationale sur la Conception de Systèmes Coopératifs ; (3 ; 1998.05.26-29 ; Cannes) ; COOP ; (3 ; 1998.05.26-29 ; Cannes) SP - 1 EP - 5 PB - - CY - Cannes ER - TY - JOUR A1 - Wolf, Martin A1 - Schlick, Christopher A1 - Springer, J. ED - Miyamoto, Hiroyuki T1 - The use of implicit communication mechanisms in desktop-teleconferencing-systems JF - Proceedings of WWDU '97 Tokyo, Fifth International Scientific Conference on Work with Display Units : November 3 - 5, 1997, Tokyo Y1 - 1997 N1 - International Scientific Conference on Work with Display Units ; International Scientific Conference on Work with Display Units ; (5 ; 1997.11.03-05 ; Tokyo) SP - 193 EP - 194 PB - - CY - Tokyo ER - TY - JOUR A1 - Wolf, Martin A1 - Luczak, Holger A1 - Springer, J. A1 - Simon, S. ED - Miyamoto, Hiroyuki T1 - The role of metaphors in computer supported cooperative work JF - Proceedings of WWDU '97 Tokyo, Fifth International Scientific Conference on Work with Display Units : November 3 - 5, 1997, Tokyo / Y1 - 1997 N1 - International Scientific Conference on Work with Display Units ; International Scientific Conference on Work with Display Units ; (5 ; 1997.11.03-05 ; Tokyo) SP - 191 EP - 192 PB - - CY - Tokyo ER - TY - JOUR A1 - Wolf, Martin A1 - Luczak, Holger T1 - Computer Supported Communication and Cooperation – Making Information Aware / Luczak, H. ; Wolf, M. JF - Human-computer interaction : proceedings of HCI International '99 (the 8th International Conference on Human-Computer Interaction), Munich, Germany, August 22 - 26, 1999 Y1 - 1999 N1 - HCI - International Conference on Human-Computer Interaction ; 8 (Munich, Germany) : 1999.08.22-26 ; in 2 Bänden SP - 298 EP - 302 PB - Erlbaum CY - Mahwah, NJ ER - TY - CHAP A1 - Wolf, Martin A1 - Lenz, Laura L. T1 - The economic effectiveness of serious games in the healthcare environment : application and evaluation of the Comparative Transformation Model (CTM) T2 - IEEE 3rd International Conference on Serious Games and Applications for Health : SeGAH 2014 ; Rio de Janeiro, Brazil, May 14 - 16 Y1 - 2015 SN - 978-1-4799-4823-9 U6 - http://dx.doi.org/10.1109/SeGAH.2014.7067089 SP - 135 EP - 142 PB - IEEE [u.a.] CY - Piscataway, NJ ER - TY - JOUR A1 - Wolf, Martin A1 - Foltz, Christian A1 - Schlick, Christopher A1 - Luczak, Holger T1 - Empirical Investigation of a workspace model for Chemical engineers / Wolf, Martin ; Foltz, Christian ; Schlick, Christopher ; Luczak, Holger JF - Proceedings of the Human Factors and Ergonomics Society Annual Meeting July 2000. 44 (2000), H. 6 Y1 - 2000 N1 - Proceedings of the IEA 2000/HFES 2000 Congress SP - 612 EP - 615 PB - - ER - TY - JOUR A1 - Wolf, Martin A1 - Foltz, Christian A1 - Schlick, Christopher A1 - Luczak, Holger T1 - Development and evaluation of a groupware system to support chemical design processes / Wolf, Martin ; Foltz, Christian ; Schlick, Christopher ; Luczak, Holger JF - International Journal of Human-Computer Interaction . 14 (2002), H. 2 Y1 - 2002 SN - 1044-7318 SP - 181 EP - 198 PB - - ER - TY - JOUR A1 - Wolf, Martin A1 - Foltz, Christian A1 - Schlick, Christopher A1 - Luczak, Holger T1 - Groupware support for chemical process design / Wolf, M.; Foltz, C.; Schlick, C.; Luczak, H. JF - Human-computer interaction : proceedings of HCI International '99 (the 8th International Conference on Human-Computer Interaction), Munich, Germany, August 22 - 26, 1999 Y1 - 1999 N1 - HCI - International Conference on Human-Computer Interaction ; 8 (Munich, Germany) : 1999.08.22-26 ; in 2 Bänden SP - 343 EP - 347 PB - Erlbaum CY - Mahwah, NJ ER - TY - JOUR A1 - Wolf, Martin A1 - Foltz, Christian A1 - Killich, Stephan A1 - Schmidt, Ludger T1 - Task and Information Modeling for Cooperative Work / Foltz, Christian ; Killich, Stephan ; Wolf, Martin ; Schmidt, Ludger ; Luczak, Holger JF - Systems, social and internationalization design aspects of human-computer interaction / ed. by Michael J. Smith, Gavriel Salvendy Vol. 2 Y1 - 2001 SN - 0-8058-3608-X N1 - International Conference on Human Computer Interaction 9, 2001, New Orleans, La. SP - 172 EP - 176 PB - - ER - TY - BOOK A1 - Wolf, Martin A1 - Foltz, Christian A1 - Killich, S. T1 - K3 User Guide Y1 - 2000 SP - 1 EP - 13 PB - RWTH CY - Aachen ER - TY - JOUR A1 - Wolf, Martin T1 - Groupware related task design JF - ACM SIGGROUP Bulletin. 21 (2000), H. 2 Y1 - 2000 SP - 5 EP - 8 PB - - ER - TY - JOUR A1 - Wolf, Martin T1 - Groupware related task design JF - ACM SIGGROUP Bulletin N2 - 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. Y1 - 2000 U6 - http://dx.doi.org/10.1145/605660.605662 SN - 2372-7403 VL - 21 IS - 2 SP - 5 EP - 8 ER - TY - CHAP A1 - Wittig, M. A1 - Rütters, René A1 - Bragard, Michael ED - Reiff-Stephan, Jörg ED - Jäkel, Jens ED - Schwarz, André T1 - Application of RL in control systems using the example of a rotatory inverted pendulum T2 - Tagungsband AALE 2024 : Fit für die Zukunft: praktische Lösungen für die industrielle Automation N2 - In this paper, the use of reinforcement learning (RL) in control systems is investigated using a rotatory inverted pendulum as an example. The control behavior of an RL controller is compared to that of traditional LQR and MPC controllers. This is done by evaluating their behavior under optimal conditions, their disturbance behavior, their robustness and their development process. All the investigated controllers are developed using MATLAB and the Simulink simulation environment and later deployed to a real pendulum model powered by a Raspberry Pi. The RL algorithm used is Proximal Policy Optimization (PPO). The LQR controller exhibits an easy development process, an average to good control behavior and average to good robustness. A linear MPC controller could show excellent results under optimal operating conditions. However, when subjected to disturbances or deviations from the equilibrium point, it showed poor performance and sometimes instable behavior. Employing a nonlinear MPC Controller in real time was not possible due to the high computational effort involved. The RL controller exhibits by far the most versatile and robust control behavior. When operated in the simulation environment, it achieved a high control accuracy. When employed in the real system, however, it only shows average accuracy and a significantly greater performance loss compared to the simulation than the traditional controllers. With MATLAB, it is not yet possible to directly post-train the RL controller on the Raspberry Pi, which is an obstacle to the practical application of RL in a prototyping or teaching setting. Nevertheless, RL in general proves to be a flexible and powerful control method, which is well suited for complex or nonlinear systems where traditional controllers struggle. KW - Rotatory Inverted Pendulum KW - MPC KW - LQR KW - PPO KW - Reinforcement Learning Y1 - 2024 SN - 978-3-910103-02-3 U6 - http://dx.doi.org/10.33968/2024.53 N1 - 20. AALE-Konferenz. Bielefeld, 06.03.-08.03.2024. (Tagungsband unter https://doi.org/10.33968/2024.29) SP - 241 EP - 248 PB - le-tex publishing services GmbH CY - Leipzig ER - TY - JOUR A1 - Wissen, M. A1 - Bogdanski, N. A1 - Scheer, H.-C. A1 - Bitz, Andreas A1 - Ahrens, G. A1 - Gruetzner, G. T1 - Implication of the light polarisation for UV curing of pre-patterned resists JF - Microelectronic Engineering Y1 - 2005 U6 - http://dx.doi.org/10.1016/j.mee.2004.12.099 SN - 0167-9317 VL - 78-79 SP - 659 EP - 664 ER - TY - CHAP A1 - Wiegner, Jonas A1 - Volker, Hanno A1 - Mainz, Fabian A1 - Backes, Andreas A1 - Löken, Michael A1 - Hüning, Felix T1 - Wiegand-effect-powered wireless IoT sensor node T2 - Sensoren und Messsysteme 2022 N2 - 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. Y1 - 2022 SN - 978-3-8007-5835-7 SP - 255 EP - 260 PB - VDE Verlag GmbH CY - Berlin ER -