@phdthesis{58680, abstract = {{Heutige On-Board-Ladewandler sind typischerweise aus zwei Stufen aufgebaut, die über einen Spannungszwischenkreis verbunden sind. Als erste Stufe kommt ein PFC-Gleichrichter zum Einsatz, der die Anforderungen an den Netzstrom bezüglich Oberschwingungsgehalt und Leistungsfaktor sicherstellt. Für die zweite Wandler-Stufe hat sich in den vergangenen Jahren ein LLC-Resonanzwandler qualifiziert, der die Ladeleistung an die Traktionsbatterie galvanisch getrennt überträgt. Der Zwischenkreis besteht aus einer Bank von Elektrolytkondensatoren, in denen die pulsierende Eingangsleistung zwischengespeichert wird. Die Kondensatoren machen einen erheblichen Teil des Lader-Volumens aus und altern schnell, was insbesondere für Ladewandler an Bord von Elektrofahrzeugen unerwünscht ist. In der vorliegenden Arbeit wird untersucht, ob diese zweistufige Struktur verworfen werden kann, indem der LLC-Resonanzwandler direkt an die gleichgerichtete Netzspannung angeschlossen wird.Zum Einsatz des LLC-Resonanzwandlers als einstufiger Ladewandler ist die Schaltung für einen großen Strom- und Spannungsbereich auszulegen. Hierfür wird in der vorliegenden Arbeit eine erweiterte Zeitbereichsanalyse erarbeitet, deren hohe Modellierungsgenauigkeit im Anschluss experimentell nachgewiesen wird. Mit Hilfe dieser Zeitbereichsanalyse werden die Belastungsgrößen des Resonanzwandlers berechnet, um hiermit eine Vorauswahl der Schaltungsparameter treffen zu können. Darauf aufbauend erfolgt die Optimierung des integrierten Transformators als Schlüsselkomponente des Ladewandlers sowie dessen prototypische Realisierung. Abschließend wird mittels Prototypen die erzielbare Leistungsdichte ermittelt. Ergebnis: Verglichen mit etablierten Ladewandlern der heutigen Elektrofahrzeuge konnte durch den einstufigen Ansatz die Leistungsdichte um ca. 53% gesteigert werden.}}, author = {{Keuck, Lukas}}, publisher = {{LibreCat University}}, title = {{{Entwurf eines einstufigen Ladewandlers auf Basis eines LLC-Resonanzwandlers}}}, doi = {{10.17619/UNIPB/1-1727}}, year = {{2023}}, } @inproceedings{58723, abstract = {{In real-world debates, the most common way to counter an argument is to reason against its main point, that is, its conclusion. Existing work on the automatic generation of natural language counter-arguments does not address the relation to the conclusion, possibly because many arguments leave their conclusion implicit. In this paper, we hypothesize that the key to effective counter-argument generation is to explicitly model the argument‘s conclusion and to ensure that the stance of the generated counter is opposite to that conclusion. In particular, we propose a multitask approach that jointly learns to generate both the conclusion and the counter of an input argument. The approach employs a stance-based ranking component that selects the counter from a diverse set of generated candidates whose stance best opposes the generated conclusion. In both automatic and manual evaluation, we provide evidence that our approach generates more relevant and stance-adhering counters than strong baselines.}}, author = {{Alshomary, Milad and Wachsmuth, Henning}}, booktitle = {{Proceedings of the 17th Conference of the European Chapter of the Association for Computational Linguistics}}, editor = {{Vlachos, Andreas and Augenstein, Isabelle}}, pages = {{957–967}}, publisher = {{Association for Computational Linguistics}}, title = {{{Conclusion-based Counter-Argument Generation}}}, doi = {{10.18653/v1/2023.eacl-main.67}}, year = {{2023}}, } @inproceedings{46426, abstract = {{One of the main challenges for next generation automotive radars is the improvement of angular resolution to a sub-degree level. In this context, wide aperture automotive radars of 1m length or more and resolution close to 0.1° in azimuth and 0.5° in elevation could be beneficial. To enable coherent processing of arrays with such large aperture, prior (i.e offline) and online calibration are necessary: channel imbalances (gains and phases) and three dimensional coordinates of transmit and receive elements need to be determined. We propose a calibration strategy based on alternating steps between the two subtasks of i) channel imbalance estimation with ‘known’ array positions, by applying a singular value decomposition to the resulting tensor calculus problem; and ii) antenna position estimation with ’known’ channel imbalances, by numerically maximizing the Bayesian posterior probability; in both cases operating on range/Doppler snapshots of disjoint targets (with potentially unknown locations). Simulation studies based on the parameters of a MIMO 8x6 linear sparse array show promising results as long as the initial position errors do not exceed half a wavelength (2mm), beyond which we observe strong effects of ambiguity. Experimental results with real measurements show that after calibration in laboratory conditions, our MIMO 8x6 demonstrator with 50cm aperture is able to resolve two targets at the same range with angular separation at least as close as 0.4°.}}, author = {{Greiff, Christian and Mateos-Núñez, David and Simoni, Renato and González-Huici, Maria and Kruse, Stephan and Scheytt, J. Christoph and Kolk, Karl and Höller, Christian and Kurz, Heiko Gustav and Meinecke, Marc-Michael and Gisder, Thomas}}, booktitle = {{2023 24th International Radar Symposium (IRS)}}, location = {{Berlin, Germany}}, publisher = {{IEEE}}, title = {{{Calibration of Large Coherent MIMO Radar Arrays: Channel Imbalances and 3D Antenna Positions}}}, doi = {{10.23919/IRS57608.2023.10172475}}, year = {{2023}}, } @inproceedings{42800, abstract = {{In this paper we present a new system architecture for software-defined radio / radar with optical signal distribution. The proposed architecture allows to transmit the optical carrier and an arbitrary IQ signal on the same fiber from a base station to wireless transmitters using a single laser. Furthermore, we can reuse parts, and under special conditions, also the complete optical output of the base station for the IQ return path from the wireless receiver frontends to the base station. Avoiding multiple lasers and fibers for the distribution of the carrier and arbitrary signal from the base station to the frontend, and avoiding the laser diode for the IQ return path from receiver frontends to the base station reduces the hardware effort significantly. Finally, the system architecture allows to integrate all components of the optoelectronic wireless frontend in a single chip using silicon photonics technology.}}, author = {{Kruse, Stephan and Kneuper, Pascal and Schwabe, Tobias and Meinecke, Marc-Michael and Kurz, Heiko G. and Scheytt, J. Christoph}}, location = {{Fraunhofer-Forum Berlin, Germany}}, title = {{{Distributed System Architecture for Software-Defined Radio / Radar with Optical Signal Distribution}}}, doi = {{10.23919/IRS57608.2023.10172470}}, year = {{2023}}, } @inproceedings{47124, author = {{Kruse, Stephan and Meinecke, Marc-Michael and Kneuper, Pascal and Schwabe, Tobias and Kurz, Heiko G. and Scheytt, J. Christoph}}, booktitle = {{2023 20th European Radar Conference (EuRAD)}}, location = {{Berlin}}, title = {{{Analysis and Simulation of a Coherent FMCW Lidar-Photonic Radar Combined Sensor System for Large Aperture Phased Array MIMO}}}, doi = {{10.23919/EuRAD58043.2023.10289439}}, year = {{2023}}, } @article{47126, author = {{Kruse, Stephan and Greitens, Jan C. and Schwabe, Tobias and Kneuper, Pascal and Kurz, Heiko G. and Scheytt, J. Christoph}}, journal = {{IEEE Microwave and Wireless Technology Letters }}, title = {{{A Narrowband Four-Quadrant Electro-Optical Mixer for Microwave Photonics}}}, doi = {{10.1109/LMWT.2023.3315315}}, year = {{2023}}, } @inproceedings{42804, abstract = {{This paper presents a method to model monolithically integrated photonic radar transceiver (TRX) with optical local oscillator (LO) distribution in silicon germanium (SiGe) electronic photonic integrated circuits (EPICs). The model proposed approximates the behavior of the nonlinear scattering (S)-parameters and noise figure of each building block of the TRX chipset by Laplace polynomials and hyperbolic tangent functions. The modular approach of the model allows to optimize hardware components with respect to the entire TRX system, and fault identification with reduced computational effort. The proposed method is validated using the first monolithically integrated photonic radar transceiver chipset and shows excellent agreement with the post layout simulation results and, including the photodiode (PD) bandwidth (BW) degradation, also with the measurements. }}, author = {{Kruse, Stephan and Schwabe, Tobias and Kneuper, Pascal and Meinecke, Marc-Michael and Kurz, Heiko G. and Scheytt, J. Christoph}}, location = {{Fraunhofer-Forum Berlin, Germany}}, title = {{{Nonlinear S-Parameter Behavioral Model of a Photonic Radar Transceiver Chipset for Automotive Applications}}}, doi = {{10.23919/IRS57608.2023.10172395}}, year = {{2023}}, } @inproceedings{47064, author = {{Iftekhar, Mohammed and Nagaraju, Harshan and Kneuper, Pascal and Sadiye, Babak and Müller, Wolfgang and Scheytt, J. Christoph}}, booktitle = {{BCICTS 2023 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium}}, location = {{MONTEREY, CALIFORNIA, USA}}, title = {{{A 28-Gb/s 27.2 mW NRZ Full-Rate Bang-Bang Clock and Data Recovery in 22 nm FD-SOI CMOS Technology }}}, year = {{2023}}, } @article{60355, abstract = {{We present a method for the generation of higher-order tetrahedral meshes. In contrast to previous methods, the curved tetrahedral elements are guaranteed to be free of degeneracies and inversions while conforming exactly to prescribed piecewise polynomial surfaces, such as domain boundaries or material interfaces. Arbitrary polynomial order is supported. Algorithmically, the polynomial input surfaces are first covered by a single layer of carefully constructed curved elements using a recursive refinement procedure that provably avoids degeneracies and inversions. These tetrahedral elements are designed such that the remaining space is bounded piecewise linearly. In this way, our method effectively reduces the curved meshing problem to the classical problem of linear mesh generation (for the remaining space).}}, author = {{Khanteimouri, Payam and Campen, Marcel}}, issn = {{0730-0301}}, journal = {{ACM Transactions on Graphics}}, number = {{6}}, pages = {{1--19}}, publisher = {{Association for Computing Machinery (ACM)}}, title = {{{3D Bézier Guarding: Boundary-Conforming Curved Tetrahedral Meshing}}}, doi = {{10.1145/3618332}}, volume = {{42}}, year = {{2023}}, } @article{60337, abstract = {{ Volumetric mapping is a ubiquitous and difficult problem in Geometry Processing and has been the subject of research in numerous and various directions. While several methods show encouraging results, the field still lacks a general approach with guarantees regarding map bijectivity. Through this work, we aim at opening the door to a new family of methods by providing a novel framework based on the concept of progressive expansion. Starting from an initial map of a tetrahedral mesh whose image may contain degeneracies but no inversions, we incrementally adjust vertex images to expand degenerate elements. By restricting movement to so-called expansion cones , it is done in such a way that the number of degenerate elements decreases in a strictly monotonic manner, without ever introducing any inversion. Adaptive local refinement of the mesh is performed to facilitate this process. We describe a prototype algorithm in the realm of this framework for the computation of maps from ball-topology tetrahedral meshes to convex or star-shaped domains. This algorithm is evaluated and compared to state-of-the-art methods, demonstrating its benefits in terms of bijectivity. We also discuss the associated cost in terms of sometimes significant mesh refinement to obtain the necessary degrees of freedom required for establishing a valid mapping. Our conclusions include that while this algorithm is only of limited immediate practical utility due to efficiency concerns, the general framework has the potential to inspire a range of novel methods improving on the efficiency aspect. }}, author = {{Nigolian, Valentin Zénon and Campen, Marcel and Bommes, David}}, issn = {{0730-0301}}, journal = {{ACM Transactions on Graphics}}, number = {{4}}, pages = {{1--19}}, publisher = {{Association for Computing Machinery (ACM)}}, title = {{{Expansion Cones: A Progressive Volumetric Mapping Framework}}}, doi = {{10.1145/3592421}}, volume = {{42}}, year = {{2023}}, } @article{60354, abstract = {{We present a set of operators to perform modifications, in particular collapses and splits, in volumetric cell complexes which are discretely embedded in a background mesh. Topological integrity and geometric embedding validity are carefully maintained. We apply these operators strategically to volumetric block decompositions, so-called T-meshes or base complexes, in the context of hexahedral mesh generation. This allows circumventing the expensive and unreliable global volumetric remapping step in the versatile meshing pipeline based on 3D integer-grid maps. In essence, we reduce this step to simpler local cube mapping problems, for which reliable solutions are available. As a consequence, the robustness of the mesh generation process is increased, especially when targeting coarse or block-structured hexahedral meshes. We furthermore extend this pipeline to support feature alignment constraints, and systematically respect these throughout, enabling the generation of meshes that align to points, curves, and surfaces of special interest, whether on the boundary or in the interior of the domain.}}, author = {{Brückler, Hendrik and Campen, Marcel}}, issn = {{0730-0301}}, journal = {{ACM Transactions on Graphics}}, number = {{6}}, pages = {{1--24}}, publisher = {{Association for Computing Machinery (ACM)}}, title = {{{Collapsing Embedded Cell Complexes for Safer Hexahedral Meshing}}}, doi = {{10.1145/3618384}}, volume = {{42}}, year = {{2023}}, } @article{60335, abstract = {{A method is presented to compute volumetric maps and parametrizations of objects over 3D domains. As a key feature, continuity and bijectivity are ensured by construction. Arbitrary objects of ball topology, represented as tetrahedral meshes, are supported. Arbitrary convex as well as star-shaped domains are supported. Full control over the boundary mapping is provided. The method is based on the technique of simplicial foliations, generalized to a broader class of domain shapes and applied adaptively in a novel localized manner. This increases flexibility as well as efficiency over the state of the art, while maintaining reliability in guaranteeing map bijectivity.}}, author = {{Hinderink, Steffen and Campen, Marcel}}, issn = {{0730-0301}}, journal = {{ACM Transactions on Graphics}}, number = {{4}}, pages = {{1--16}}, publisher = {{Association for Computing Machinery (ACM)}}, title = {{{Galaxy Maps: Localized Foliations for Bijective Volumetric Mapping}}}, doi = {{10.1145/3592410}}, volume = {{42}}, year = {{2023}}, } @article{60333, abstract = {{AbstractWe describe HalfedgeCNN, a collection of modules to build neural networks that operate on triangle meshes. Taking inspiration from the (edge‐based) MeshCNN, convolution, pooling, and unpooling layers are consistently defined on the basis of halfedges of the mesh, pairs of oppositely oriented virtual instances of each edge. This provides benefits over alternative definitions on the basis of vertices, edges, or faces. Additional interface layers enable support for feature data associated with such mesh entities in input and output as well. Due to being defined natively on mesh entities and their neighborhoods, lossy resampling or interpolation techniques (to enable the application of operators adopted from image domains) do not need to be employed. The operators have various degrees of freedom that can be exploited to adapt to application‐specific needs.}}, author = {{Ludwig, Ingmar and Tyson, Daniel and Campen, Marcel}}, issn = {{0167-7055}}, journal = {{Computer Graphics Forum}}, number = {{5}}, publisher = {{Wiley}}, title = {{{HalfedgeCNN for Native and Flexible Deep Learning on Triangle Meshes}}}, doi = {{10.1111/cgf.14898}}, volume = {{42}}, year = {{2023}}, } @inproceedings{46500, abstract = {{The security of Industrial Control Systems is relevant both for reliable production system operations and for high-quality throughput in terms of manufactured products. Security measures are designed, operated and maintained by different roles along product and production system lifecycles. Defense-in-Depth as a paradigm builds upon the assumption that breaches are unavoidable. The paper at hand provides an analysis of roles, corresponding Human Factors and their relevance for data theft and sabotage attacks. The resulting taxonomy is reflected by an example related to Additive Manufacturing. The results assist in both designing and redesigning Industrial Control System as part of an entire production system so that Defense-in-Depth with regard to Human Factors is built in by design.}}, author = {{Pottebaum, Jens and Rossel, Jost and Somorovsky, Juraj and Acar, Yasemin and Fahr, René and Arias Cabarcos, Patricia and Bodden, Eric and Gräßler, Iris}}, booktitle = {{2023 IEEE European Symposium on Security and Privacy Workshops (EuroS&PW)}}, keywords = {{Defense-in-Depth, Human Factors, Production Engineering, Product Design, Systems Engineering}}, location = {{Delft, Netherlands}}, pages = {{379--385}}, publisher = {{IEEE}}, title = {{{Re-Envisioning Industrial Control Systems Security by Considering Human Factors as a Core Element of Defense-in-Depth}}}, doi = {{10.1109/eurospw59978.2023.00048}}, year = {{2023}}, } @inproceedings{48012, abstract = {{3D printing is a well-established technology with rapidly increasing usage scenarios both in the industry and consumer context. The growing popularity of 3D printing has also attracted security researchers, who have analyzed possibilities for weakening 3D models or stealing intellectual property from 3D models. We extend these important aspects and provide the first comprehensive security analysis of 3D printing data formats. We performed our systematic study on the example of the 3D Manufacturing Format (3MF), which offers a large variety of features that could lead to critical attacks. Based on 3MF’s features, we systematized three attack goals: Data Exfiltration (dex), Denial of Service, and UI Spoofing (uis). We achieve these goals by exploiting the complexity of 3MF, which is based on the Open Packaging Conventions (OPC) format and uses XML to define 3D models. In total, our analysis led to 352 tests. To create and run these tests automatically, we implemented an open-source tool named 3MF Analyzer (tool), which helped us evaluate 20 applications.}}, author = {{Rossel, Jost and Mladenov, Vladislav and Somorovsky, Juraj}}, booktitle = {{Proceedings of the 26th International Symposium on Research in Attacks, Intrusions and Defenses}}, keywords = {{Data Format Security, 3D Manufacturing Format, 3D Printing, Additive Manufacturing}}, location = {{Hongkong}}, publisher = {{ACM}}, title = {{{Security Analysis of the 3MF Data Format}}}, doi = {{10.1145/3607199.3607216}}, year = {{2023}}, } @inproceedings{47448, abstract = {{In XAI it is important to consider that, in contrast to explanations for professional audiences, one cannot assume common expertise when explaining for laypeople. But such explanations between humans vary greatly, making it difficult to research commonalities across explanations. We used the dual nature theory, a techno-philosophical approach, to cope with these challenges. According to it, one can explain, for example, an XAI's decision by addressing its dual nature: by focusing on the Architecture (e.g., the logic of its algorithms) or the Relevance (e.g., the severity of a decision, the implications of a recommendation). We investigated 20 game explanations using the theory as an analytical framework. We elaborate how we used the theory to quickly structure and compare explanations of technological artifacts. We supplemented results from analyzing the explanation contents with results from a video recall to explore how explainers justified their explanation. We found that explainers were focusing on the physical aspects of the game first (Architecture) and only later on aspects of the Relevance. Reasoning in the video recalls indicated that EX regarded the focus on the Architecture as important for structuring the explanation initially by explaining the basic components before focusing on more complex, intangible aspects. Shifting between addressing the two sides was justified by explanation goals, emerging misunderstandings, and the knowledge needs of the explainee. We discovered several commonalities that inspire future research questions which, if further generalizable, provide first ideas for the construction of synthetic explanations.}}, author = {{Terfloth, Lutz and Schaffer, Michael and Buhl, Heike M. and Schulte, Carsten}}, isbn = {{978-3-031-44069-4}}, location = {{Lisboa}}, publisher = {{Springer, Cham}}, title = {{{Adding Why to What? Analyses of an Everyday Explanation}}}, doi = {{10.1007/978-3-031-44070-0_13}}, year = {{2023}}, } @inbook{54588, author = {{Manzoor, Ali and Saleem, Muhammad and Moussallem, Diego and Sherif, Mohamed and Ngonga Ngomo, Axel-Cyrille}}, booktitle = {{The Semantic Web}}, isbn = {{9783031334542}}, issn = {{0302-9743}}, publisher = {{Springer Nature Switzerland}}, title = {{{RELD: A Knowledge Graph of Relation Extraction Datasets}}}, doi = {{10.1007/978-3-031-33455-9_20}}, year = {{2023}}, } @article{61252, abstract = {{AbstractThe biexciton‐exciton emission cascade commonly used in quantum‐dot systems to generate polarization entanglement yields photons with intrinsically limited indistinguishability. In the present work, it focuses on the generation of pairs of photons with high degrees of polarization entanglement and simultaneously high indistinguishability. It achieves this goal by selectively reducing the biexciton lifetime with an optical resonator. It demonstrates that a suitably tailored circular Bragg reflector fulfills the requirements of sufficient selective Purcell enhancement of biexciton emission paired with spectrally broad photon extraction and twofold degenerate optical modes. The in‐depth theoretical study combines (i) the optimization of realistic photonic structures solving Maxwell's equations from which model parameters are extracted as input for (ii) microscopic simulations of quantum‐dot cavity excitation dynamics with full access to photon properties. It reports non‐trivial dependencies on system parameters and use the predictive power of the combined theoretical approach to determine the optimal range of Purcell enhancement that maximizes indistinguishability and entanglement to near unity values, here specifically for the telecom C‐band at 1550 nm.}}, author = {{Bauch, David and Siebert, Dustin and Jöns, Klaus D. and Förstner, Jens and Schumacher, Stefan}}, issn = {{2511-9044}}, journal = {{Advanced Quantum Technologies}}, number = {{1}}, publisher = {{Wiley}}, title = {{{On‐Demand Indistinguishable and Entangled Photons Using Tailored Cavity Designs}}}, doi = {{10.1002/qute.202300142}}, volume = {{7}}, year = {{2023}}, } @inbook{46191, author = {{Alt, Christoph and Kenter, Tobias and Faghih-Naini, Sara and Faj, Jennifer and Opdenhövel, Jan-Oliver and Plessl, Christian and Aizinger, Vadym and Hönig, Jan and Köstler, Harald}}, booktitle = {{Lecture Notes in Computer Science}}, isbn = {{9783031320408}}, issn = {{0302-9743}}, publisher = {{Springer Nature Switzerland}}, title = {{{Shallow Water DG Simulations on FPGAs: Design and Comparison of a Novel Code Generation Pipeline}}}, doi = {{10.1007/978-3-031-32041-5_5}}, year = {{2023}}, } @inproceedings{46190, author = {{Opdenhövel, Jan-Oliver and Plessl, Christian and Kenter, Tobias}}, booktitle = {{Proceedings of the 13th International Symposium on Highly Efficient Accelerators and Reconfigurable Technologies (HEART)}}, publisher = {{ACM}}, title = {{{Mutation Tree Reconstruction of Tumor Cells on FPGAs Using a Bit-Level Matrix Representation}}}, doi = {{10.1145/3597031.3597050}}, year = {{2023}}, }