@article{GraesslRenzHezeletal.2013, author = {Gr{\"a}ßl, Andreas and Renz, Wolfgang and Hezel, Fabian and Dieringer, Matthias A. and Winter, Lukas and {\"O}zerdem, Celal and Rieger, Jan and Kellmann, Peter and Santoro, Davide and Lindel, Tomasz D. and Frauenrath, Tobias and Pfeiffer, Harald and Niendorf, Thoralf}, title = {Modular 32-channel transceiver coil array for cardiac MRI at 7.0T}, series = {Magnetic Resonance in Medicine}, volume = {72}, journal = {Magnetic Resonance in Medicine}, number = {1}, publisher = {Wiley-Liss}, address = {New York}, issn = {1522-2594}, doi = {10.1002/mrm.24903}, pages = {276 -- 290}, year = {2013}, abstract = {Purpose To design and evaluate a modular transceiver coil array with 32 independent channels for cardiac MRI at 7.0T. Methods The modular coil array comprises eight independent building blocks, each containing four transceiver loop elements. Numerical simulations were used for B1+ field homogenization and radiofrequency (RF) safety validation. RF characteristics were examined in a phantom study. The array's suitability for accelerated high spatial resolution two-dimensional (2D) FLASH CINE imaging of the heart was examined in a volunteer study. Results Transmission field adjustments and RF characteristics were found to be suitable for the volunteer study. The signal-to-noise intrinsic to 7.0T together with the coil performance afforded a spatial resolution of 1.1 × 1.1 × 2.5 mm3 for 2D CINE FLASH MRI, which is by a factor of 6 superior to standardized CINE protocols used in clinical practice at 1.5T. The 32-channel transceiver array supports one-dimensional acceleration factors of up to R = 4 without impairing image quality significantly. Conclusion The modular 32-channel transceiver cardiac array supports accelerated and high spatial resolution cardiac MRI. The array is compatible with multichannel transmission and provides a technological basis for future clinical assessment of parallel transmission techniques at 7.0T.}, language = {en} } @article{FerreinKonurLakemeyer2004, author = {Ferrein, Alexander and Konur, Savas and Lakemeyer, Gerhard}, title = {Learning Decision Trees for Action Selection in Soccer Agents / Konur, Savas ; Ferrein, Alexander ; Lakemeyer, Gerhard}, pages = {1 -- 7}, year = {2004}, language = {en} } @article{Ferrein2005, author = {Ferrein, Alexander}, title = {Specifying Soccer Moves with Golog}, series = {Book of abstracts : Cologne, 15 - 17 September 2004 / 1st International Working Conference IT and Sport \& 5th conference DVS-Section Computer Science in Sport}, journal = {Book of abstracts : Cologne, 15 - 17 September 2004 / 1st International Working Conference IT and Sport \& 5th conference DVS-Section Computer Science in Sport}, publisher = {German Sport Univ.}, address = {K{\"o}ln}, isbn = {3-00-014576-1}, pages = {161 -- 165}, year = {2005}, language = {en} } @article{SchoppDollGraeseretal.2016, author = {Schopp, Christoph and Doll, Timo and Gr{\"a}ser, Ulrich and Harzheim, Thomas and Heuermann, Holger and Kling, Rainer and Marso, Michael}, title = {Capacitively Coupled High-Pressure Lamp Using Coaxial Line Networks}, series = {IEEE Transactions on Microwave Theory and Techniques}, volume = {64}, journal = {IEEE Transactions on Microwave Theory and Techniques}, number = {10}, publisher = {IEEE}, address = {New York, NY}, issn = {0018-9480}, doi = {10.1109/TMTT.2016.2600326}, pages = {3363 -- 3368}, year = {2016}, abstract = {This paper describes the development of a capacitively coupled high-pressure lamp with input power between 20 and 43 W at 2.45 GHz, using a coaxial line network. Compared with other electrodeless lamp systems, no cavity has to be used and a reduction in the input power is achieved. Therefore, this lamp is an alternative to the halogen incandescent lamp for domestic lighting. To serve the demands of domestic lighting, the filling of the lamp is optimized over all other resulting requirements, such as high efficacy at low induced powers and fast startups. A workflow to develop RF-driven plasma applications is presented, which makes use of the hot S-parameter technique. Descriptions of the fitting process inside a circuit and FEM simulator are given. Results of the combined ignition and operation network from simulations and measurements are compared. An initial prototype is built and measurements of the lamp's lighting properties are presented along with an investigation of the efficacy optimizations using large signal amplitude modulation. With this lamp, an efficacy of 135 lmW -1 is achieved.}, language = {en} } @article{HeuermannSchiek1997, author = {Heuermann, Holger and Schiek, Burkhard}, title = {Line Network Network (LNN): an alternative in-fixture calibration procedure}, series = {IEEE transactions on microwave theory and techniques : MTT ; a publication of the IEEE Microwave Theory and Techniques Society. 45 (1997), H. 3}, journal = {IEEE transactions on microwave theory and techniques : MTT ; a publication of the IEEE Microwave Theory and Techniques Society. 45 (1997), H. 3}, isbn = {0018-9480}, pages = {408 -- 413}, year = {1997}, language = {en} } @article{HeuermannPetersSchmitzetal.2005, author = {Heuermann, Holger and Peters, N. and Schmitz, T. and Sadeghfam, Arash}, title = {Concept of Balanced Antennas with Load-Invariant Base Impedance Using a Two Element LC-Coupler. Peters, N., Schmitz, Th., Sadeghfam, A., Heuermann, H.}, series = {Proceedings of the European microwave association : journal of the European microwave association}, journal = {Proceedings of the European microwave association : journal of the European microwave association}, publisher = {PLUS}, address = {Pisa}, pages = {117 -- 122}, year = {2005}, language = {en} } @article{FoltzSchneiderWolfetal.2008, author = {Foltz, Christian and Schneider, Nicole and Wolf, Martin R. and Kausch, Bernhard and Schlick, Christopher and Luczak, Holger}, title = {Usability engineering}, series = {Collaborative and distributed chemical engineering : from understanding to substantial design process support; results of the IMPROVE Project. - (Lecture notes in computer science ; 4970)}, journal = {Collaborative and distributed chemical engineering : from understanding to substantial design process support; results of the IMPROVE Project. - (Lecture notes in computer science ; 4970)}, editor = {Nagl, Manfred}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-540-70552-9}, doi = {10.1007/978-3-540-70552-9_21}, pages = {527 -- 554}, year = {2008}, language = {en} } @article{FerreinBeckLakemeyer2007, author = {Ferrein, Alexander and Beck, Daniel and Lakemeyer, Gerhard}, title = {A Simulation Environment for Middle-Size Robots with Multi-level Abstraction / Beck, Daniel ; Ferrein, Alexander ; Lakemeyer, Gerhard}, series = {RoboCup 2007: Robot Soccer World Cup XI}, journal = {RoboCup 2007: Robot Soccer World Cup XI}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-540-68846-4}, pages = {136 -- 147}, year = {2007}, language = {en} } @article{HeuermannSadeghfam2007, author = {Heuermann, Holger and Sadeghfam, Arash}, title = {On the design of multimode integrated circuits in multilayered processes / Sadeghfam, A. ; Heuermann, H.}, series = {European Microwave Conference, 2007, 9-12 Oct. 2007}, journal = {European Microwave Conference, 2007, 9-12 Oct. 2007}, isbn = {978-2-87487-001-9}, pages = {516 -- 519}, year = {2007}, language = {en} } @article{WolfAltgen2013, author = {Wolf, Martin R. and Altgen, Jannik}, title = {IT Service Management in der Region Aachen : White Paper}, pages = {1 -- 13}, year = {2013}, language = {de} } @article{FerreinJacobsSchifferetal.2009, author = {Ferrein, Alexander and Jacobs, Stefan and Schiffer, Stefan and Beck, Daniel}, title = {Robust Collision Avoidance in Unknown Domestic Environments / Jacobs, Stefan ; Ferrein, Alexander ; Schiffer, Stefan ; Beck, Daniel ; Lakemeyer, Gerhard}, series = {ROBOCUP 2009: ROBOT SOCCER WORLD CUP XIII}, journal = {ROBOCUP 2009: ROBOT SOCCER WORLD CUP XIII}, publisher = {Springer}, address = {Berlin}, pages = {116 -- 127}, year = {2009}, language = {en} } @article{FerreinDyllaLakemeyeretal.2005, author = {Ferrein, Alexander and Dylla, Frank and Lakemeyer, Gerhard and Murray, Jan}, title = {Towards a League-Independent Qualitative Soccer Theory for RoboCup / Dylla, Frank ; Ferrein, Alexander ; Lakemeyer, Gerhard ; Murray, Jan ; Obst, Oliver ; R{\"o}fer, Thomas ; Stolzenburg, Frieder ; Visser, Ubbo}, series = {RoboCup 2004: Robot Soccer World Cup VIII / Daniele Nardi ... (ed.).}, journal = {RoboCup 2004: Robot Soccer World Cup VIII / Daniele Nardi ... (ed.).}, publisher = {Springer}, address = {Berlin}, isbn = {978-3-540-25046-8}, pages = {611 -- 618}, year = {2005}, language = {en} } @article{HeuermannGraf1998, author = {Heuermann, Holger and Graf, W.}, title = {Direkte on-wafer-Messung des Wellenwiderstandes einer Mikrostreifenleitung}, series = {Kleinheubacher Berichte : Vortr{\"a}ge und Berichte der gemeinsamen Tagung des U.R.S.I.-Landesausschusses in der Bundesrepublik Deutschland / Hrsg.: Deutsche Telekom AG. 41. 1998 (1998)}, journal = {Kleinheubacher Berichte : Vortr{\"a}ge und Berichte der gemeinsamen Tagung des U.R.S.I.-Landesausschusses in der Bundesrepublik Deutschland / Hrsg.: Deutsche Telekom AG. 41. 1998 (1998)}, year = {1998}, language = {de} } @article{RoepkeKoehlerDruryetal.2020, author = {Roepke, Rene and K{\"o}hler, Klemens and Drury, Vincent and Schroeder, Ulrik and Wolf, Martin R. 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} } @article{SchoppRohrbachLangeretal.2024, author = {Schopp, Christoph and Rohrbach, Felix and Langer, Luc and Heuermann, Holger}, title = {Detection of welding wire length by active S11 measurement}, series = {IEEE Transactions on Plasma Science}, journal = {IEEE Transactions on Plasma Science}, number = {Early Access}, publisher = {IEEE}, issn = {0093-3813 (Print)}, doi = {10.1109/TPS.2024.3356659}, pages = {1 -- 6}, year = {2024}, abstract = {A novel method to determine the extruded length of a metallic wire for a directed energy deposition (DED) process using a microwave (MW) plasma jet with a straight-through wire feed is presented. The method is based on the relative comparison of the measured frequency response obtained by the large-signal scattering parameter (Hot-S) technique. In the practical working range, repeatability of less than 6\% for a nonactive plasma and 9\% for the active plasma state is found. Measurements are conducted with a focus on a simple solution to decrease the processing time and reduce the integration time of the process into the existing hardware. It is shown that monitoring a single frequency for magnitude and phase changes is sufficient to achieve good accuracy. A combination of different measurement values to determine the length is possible. The applicability to different diameter of the same material is shown as well as a contact detection of the wire and metallic substrate.}, language = {en} } @article{HeuermannSchiek1993, author = {Heuermann, Holger and Schiek, B.}, title = {Procedures for the Determination of the Scattering Parameters for Network Analyzer Calibration}, series = {IEEE transactions on instrumentation and measurement : IM / Institute of Electrical and Electronics Engineers, Instrumentation and Measurement Group. 42 (1993), H. 2}, journal = {IEEE transactions on instrumentation and measurement : IM / Institute of Electrical and Electronics Engineers, Instrumentation and Measurement Group. 42 (1993), H. 2}, isbn = {0018-9456}, pages = {528 -- 531}, year = {1993}, language = {en} } @article{FerreinBeckLakemeyer2009, author = {Ferrein, Alexander and Beck, Daniel and Lakemeyer, Gerhard}, title = {Landmark-Based Representations for Navigating Holonomic Soccer Robots / Beck, Daniel ; Ferrein, Alexander ; Lakemeyer, Gerhard}, series = {RoboCup 2008 : robot soccer world cup XII / Luca Iocchi ... (eds.)}, journal = {RoboCup 2008 : robot soccer world cup XII / Luca Iocchi ... (eds.)}, publisher = {Springer}, address = {Heidelberg}, isbn = {978-3-642-02921-9}, pages = {25 -- 36}, year = {2009}, language = {en} } @article{HeuermannGraf1997, author = {Heuermann, Holger and Graf, W.}, title = {Direkte Messung der Dispersion des Wellenwiderstandes einer Mikrostreifenleitung}, series = {Kleinheubacher Berichte : Vortr{\"a}ge und Berichte der gemeinsamen Tagung des U.R.S.I.-Landesausschusses in der Bundesrepublik Deutschland / Hrsg.: Deutsche Telekom AG. 40. 1997 (1997)}, journal = {Kleinheubacher Berichte : Vortr{\"a}ge und Berichte der gemeinsamen Tagung des U.R.S.I.-Landesausschusses in der Bundesrepublik Deutschland / Hrsg.: Deutsche Telekom AG. 40. 1997 (1997)}, year = {1997}, language = {de} } @article{HeuermannSadeghfam2008, author = {Heuermann, Holger and Sadeghfam, Arash}, title = {Electrically tunable bandpass filter with integrated carrier suppression for UHF RFID systems / Sadeghfam, Arash ; Heuermann, Holger}, series = {European Conference on Wireless Technology, 2008. EuWiT 2008.}, journal = {European Conference on Wireless Technology, 2008. EuWiT 2008.}, isbn = {978-2-87487-008-8}, pages = {306 -- 309}, year = {2008}, language = {en} } @article{Heuermann2008, author = {Heuermann, Holger}, title = {Calibration of a Network Analyzer Without a Thru Connection for Nonlinear and Multiport Measurements}, series = {IEEE Transactions on Microwave Theory and Techniques. 56 (2008), H. 11, 1}, journal = {IEEE Transactions on Microwave Theory and Techniques. 56 (2008), H. 11, 1}, isbn = {0018-9480}, pages = {2505 -- 2510}, year = {2008}, language = {en} }