@article{28196, abstract = {{We show that narrow trenches in a high-contrast silicon-photonics slab can act as lossless power dividers for semi-guided waves. Reflectance and transmittance can be easily configured by selecting the trench width. At sufficiently high angles of incidence, the devices are lossless, apart from material attenuation and scattering due to surface roughness. We numerically simulate a series of devices within the full 0-to-1-range of splitting ratios, for semi-guided plane wave incidence as well as for excitation by focused Gaussian wave bundles. Straightforward cascading of the trenches leads to concepts for 1×M-power dividers and a polarization beam splitter.}}, author = {{Hammer, Manfred and Ebers, Lena and Förstner, Jens}}, issn = {{2578-7519}}, journal = {{OSA Continuum}}, keywords = {{tet_topic_waveguide}}, number = {{12}}, pages = {{3081}}, title = {{{Configurable lossless broadband beam splitters for semi-guided waves in integrated silicon photonics}}}, doi = {{10.1364/osac.437549}}, volume = {{4}}, year = {{2021}}, } @article{30649, abstract = {{Nowadays, the production of modern lightweight structures, like a body in white structure requires a wide variety of mechanical joining processes. To fulfill the various demands, mechanical joining processes and joining elements (JE) are used. Very often, they are adapted to the application, which leads in turn to a numerous of different variants, high costs, and loss of the process chain versatility. To overcome this drawback, an innovative approach is the usage of individually produced and task-adapted JE, the so-called friction spun joint connectors (FSJC). These connectors can be modified in shape as well as in material properties. This flexibility offers high potential for lightweight design but also increases the necessary analytical effort regarding the forming process as well as the manufactured joint's properties. Therefore, a new analysis strategy based on the Finite-Element-Method (FEM) is proposed, which numerically determines the local load bearing capacity within a given joint in order to identify the critical regions for load transfer. The process of joining element manufacturing and the analysis strategy will be described in detail and optimization results of the joints are shown. Numerical results are discussed and possible recommendations for joint manufacturing are derived.}}, author = {{Wischer, Christian and Steinfelder, Christian and Homberg, Werner and Brosius, Alexander}}, journal = {{IOP Conference Series: Materials Science and Engineering}}, pages = {{012007}}, title = {{{Joining with Friction Spun Joint Connectors – Manufacturing and Analysis}}}, doi = {{10.1088/1757-899x/1157/1/012007}}, volume = {{1157}}, year = {{2021}}, } @article{30702, author = {{Wischer, Christian and Homberg, Werner}}, journal = {{Production Engineering}}, title = {{{A contribution on versatile process chains: joining with adaptive joining elements, formed by friction spinning}}}, doi = {{10.1007/s11740-021-01094-8}}, year = {{2021}}, } @article{26987, abstract = {{Optical metasurfaces are perfect candidates for the phase and amplitude modulation of light, featuring an excellent basis for holographic applications. In this work, we present a dual amplitude holographic scheme based on the photon sieve principle, which is then combined with a phase hologram by utilizing the Pancharatnam–Berry phase. We demonstrate that two types of apertures, rectangular and square shapes in a gold film filled with silicon nanoantennas are sufficient to create two amplitude holograms at two different wavelengths in the visible, multiplexed with an additional phase-only hologram. The nanoantennas are tailored to adjust the spectral transmittance of the apertures, enabling the wavelength sensitivity. The phase-only hologram is implemented by utilizing the anisotropic rectangular structure. Interestingly, such three holograms have quantitative mathematical correlations with each other. Thus, the flexibility of polarization and wavelength channels can be utilized with custom-tailored features to achieve such amplitude and phase holography simultaneously without sacrificing any space-bandwidth product. The present scheme has the potential to store different pieces of information which can be displayed separately by switching the wavelength or the polarization state of the reading light beam.}}, author = {{Frese, Daniel and Sain, Basudeb and Zhou, Hongqiang and Wang, Yongtian and Huang, Lingling and Zentgraf, Thomas}}, issn = {{2192-8614}}, journal = {{Nanophotonics}}, number = {{18}}, pages = {{4543--4550}}, publisher = {{De Gruyter}}, title = {{{A wavelength and polarization selective photon sieve for holographic applications}}}, doi = {{10.1515/nanoph-2021-0440}}, volume = {{10}}, year = {{2021}}, } @article{26854, author = {{Moritzer, Elmar and Flachmann, Felix}}, journal = {{Kunststoffe}}, pages = {{42--44}}, title = {{{Die Fließfront darf nicht brechen}}}, volume = {{12}}, year = {{2021}}, } @inproceedings{22482, author = {{Yigitbas, Enes and Klauke, Jonas and Gottschalk, Sebastian and Engels, Gregor}}, booktitle = {{Proceedings of the 2021 IEEE Symposium on Visual Languages and Human-Centric Computing (VL/HCC) }}, publisher = {{IEEE}}, title = {{{VREUD - An End-User Development Tool to Simplify the Creation of Interactive VR Scenes}}}, year = {{2021}}, } @inproceedings{29715, author = {{Steghofer, Jan-Philipp and Koopmann, Bjorn and Steffen Becker, Jan and Stierand, Ingo and Zeller, Marc and Bonner, Maria and Schmelter, David and Maro, Salome}}, booktitle = {{2021 IEEE 29th International Requirements Engineering Conference (RE)}}, publisher = {{IEEE}}, title = {{{The MobSTr Dataset – An Exemplar for Traceability and Model-based Safety Assessment}}}, doi = {{10.1109/re51729.2021.00062}}, year = {{2021}}, } @article{31261, abstract = {{Abstract For a compact Riemannian locally symmetric space $\mathcal M$ of rank 1 and an associated vector bundle $\mathbf V_{\tau }$ over the unit cosphere bundle $S^{\ast }\mathcal M$, we give a precise description of those classical (Pollicott–Ruelle) resonant states on $\mathbf V_{\tau }$ that vanish under covariant derivatives in the Anosov-unstable directions of the chaotic geodesic flow on $S^{\ast }\mathcal M$. In particular, we show that they are isomorphically mapped by natural pushforwards into generalized common eigenspaces of the algebra of invariant differential operators $D(G,\sigma )$ on compatible associated vector bundles $\mathbf W_{\sigma }$ over $\mathcal M$. As a consequence of this description, we obtain an exact band structure of the Pollicott–Ruelle spectrum. Further, under some mild assumptions on the representations $\tau$ and $\sigma$ defining the bundles $\mathbf V_{\tau }$ and $\mathbf W_{\sigma }$, we obtain a very explicit description of the generalized common eigenspaces. This allows us to relate classical Pollicott–Ruelle resonances to quantum eigenvalues of a Laplacian in a suitable Hilbert space of sections of $\mathbf W_{\sigma }$. Our methods of proof are based on representation theory and Lie theory.}}, author = {{Küster, Benjamin and Weich, Tobias}}, issn = {{1073-7928}}, journal = {{International Mathematics Research Notices}}, keywords = {{General Mathematics}}, number = {{11}}, pages = {{8225--8296}}, publisher = {{Oxford University Press (OUP)}}, title = {{{Quantum-Classical Correspondence on Associated Vector Bundles Over Locally Symmetric Spaces}}}, doi = {{10.1093/imrn/rnz068}}, volume = {{2021}}, year = {{2021}}, } @article{29524, author = {{De, Syamsundar and Gil López, Jano and Brecht, Benjamin and Silberhorn, Christine and Sánchez-Soto, Luis L. and Hradil, Zdeněk and Řeháček, Jaroslav}}, issn = {{2643-1564}}, journal = {{Physical Review Research}}, keywords = {{General Engineering}}, number = {{3}}, publisher = {{American Physical Society (APS)}}, title = {{{Effects of coherence on temporal resolution}}}, doi = {{10.1103/physrevresearch.3.033082}}, volume = {{3}}, year = {{2021}}, } @article{22259, author = {{Roman-Rodriguez, V and Brecht, Benjamin and Srinivasan, K and Silberhorn, Christine and Treps, N and Diamanti, E and Parigi, V}}, issn = {{1367-2630}}, journal = {{New Journal of Physics}}, title = {{{Continuous variable multimode quantum states via symmetric group velocity matching}}}, doi = {{10.1088/1367-2630/abef96}}, volume = {{23}}, year = {{2021}}, } @misc{31707, author = {{Moritzer, Elmar and Hillemeyer, J. and Kramer, M. and Hopmann, C. }}, booktitle = {{Plastverarbeiter}}, issn = {{0032-1338}}, number = {{71}}, pages = {{56--60}}, title = {{{Direktverschraubung von Duroplasten Eine wirtschaftliche Lösung}}}, year = {{2021}}, } @misc{31725, author = {{Moritzer, Elmar and Wortmann, Martin and Viertel, Klaus and Welle, Alexander and Keil, Waldemar and Frese, Natalie and Hachmann, Wiebke and Krieger, Philipp and Brikmann, Johannes and Schmidt, Claudia and Hüsgen, Bruno}}, booktitle = {{International Journal of Heat and Mass Transfer}}, title = {{{Anomalous bulk diffusion of methylene diphenyl diisocyanate in silicone elastomer}}}, year = {{2021}}, } @inproceedings{31719, author = {{Schöppner, Volker and Vogtschmidt, Sascha}}, booktitle = {{ DVS CONGRESS}}, isbn = {{978-3-96144-147-1}}, location = {{digital}}, title = {{{ Analyse des Erwärm- und Umstellverhaltens beim Schweißen von hochtemperaturbeständigen Kunststoffen}}}, year = {{2021}}, } @inproceedings{21726, author = {{Triebus, Marcel and Tröster, Thomas}}, booktitle = {{9th NRW Nano Conference - Innovations in Materials and Applications}}, location = {{Web}}, title = {{{HyOpt - Optimization-Based Development of Hybrid Materials}}}, year = {{2021}}, } @inproceedings{28988, author = {{Kirchhoff, Jonas}}, booktitle = {{The 1st Early Career Researchers Workshop Co-Located with ECSS 2021}}, location = {{Madrid}}, title = {{{Providing Decision Makers with Tailored Decision Support Systems}}}, year = {{2021}}, } @inproceedings{21198, author = {{Hanselle, Jonas Manuel and Tornede, Alexander and Wever, Marcel Dominik and Hüllermeier, Eyke}}, location = {{Delhi, India}}, title = {{{Algorithm Selection as Superset Learning: Constructing Algorithm Selectors from Imprecise Performance Data}}}, year = {{2021}}, } @unpublished{27778, abstract = {{Consider a set of jobs connected to a directed acyclic task graph with a fixed source and sink. The edges of this graph model precedence constraints and the jobs have to be scheduled with respect to those. We introduce the Server Cloud Scheduling problem, in which the jobs have to be processed either on a single local machine or on one of many cloud machines. Both the source and the sink have to be scheduled on the local machine. For each job, processing times both on the server and in the cloud are given. Furthermore, for each edge in the task graph, a communication delay is included in the input and has to be taken into account if one of the two jobs is scheduled on the server, the other in the cloud. The server can process jobs sequentially, whereas the cloud can serve as many as needed in parallel, but induces costs. We consider both makespan and cost minimization. The main results are an FPTAS with respect for the makespan objective for a fairly general case and strong hardness for the case with unit processing times and delays.}}, author = {{Maack, Marten and Meyer auf der Heide, Friedhelm and Pukrop, Simon}}, booktitle = {{arXiv:2108.02109}}, title = {{{Full Version -- Server Cloud Scheduling}}}, year = {{2021}}, } @inproceedings{26407, author = {{Piskachev, Goran and Krishnamurthy, Ranjith and Bodden, Eric}}, booktitle = {{2021 IEEE 21st International Working Conference on Source Code Analysis and Manipulation (SCAM)}}, title = {{{SecuCheck: Engineering configurable taint analysis for software developers}}}, year = {{2021}}, } @article{23728, abstract = {{We demonstrate the integration of amorphous tungsten silicide superconducting nanowire single-photon detectors on titanium in-diffused lithium niobate waveguides. We show proof-of-principle detection of evanescently coupled photons of 1550 nm wavelength using bidirectional waveguide coupling for two orthogonal polarization directions. We investigate the internal detection efficiency as well as detector absorption using coupling-independent characterization measurements. Furthermore, we describe strategies to improve the yield and efficiency of these devices.}}, author = {{Höpker, Jan Philipp and Verma, Varun B and Protte, Maximilian and Ricken, Raimund and Quiring, Viktor and Eigner, Christof and Ebers, Lena and Hammer, Manfred and Förstner, Jens and Silberhorn, Christine and Mirin, Richard P and Woo Nam, Sae and Bartley, Tim}}, issn = {{2515-7647}}, journal = {{Journal of Physics: Photonics}}, pages = {{034022}}, title = {{{Integrated superconducting nanowire single-photon detectors on titanium in-diffused lithium niobate waveguides}}}, doi = {{10.1088/2515-7647/ac105b}}, volume = {{3}}, year = {{2021}}, } @article{33895, abstract = {{Heat-assisted forming processes are becoming increasingly important in the manufacturing of sheet metal parts for body-in-white applications. However, the non-isothermal nature of these processes leads to challenges in evaluating the forming limits, since established methods such as Forming Limit Curves (FLCs) only allow the assessment of critical forming strains for steady temperatures. For this reason, a temperature-dependent extension of the well-established GISSMO (Generalized Incremental Stress State Dependent Damage Model) fracture indicator framework is developed by the authors to predict forming failures under non-isothermal conditions. In this paper, a general approach to combine several isothermal FLCs within the temperature-extended GISSMO model into a temperature-dependent forming limit surface is investigated. The general capabilities of the model are tested in a coupled thermo-mechanical FEA using the example of warm forming of an AA5182-O sheet metal cross-die cup. The obtained results are then compared with state of the art of evaluation methods. By taking the strain and temperature path into account, GISSMO predicts greater drawing depths by up to 20% than established methods. In this way the forming and so the lightweight potential of sheet metal parts can by fully exploited. Moreover, the risk and locus of failure can be evaluated directly on the part geometry by a contour plot. An additional advantage of the GISSMO model is the applicability for low triaxialities as well as the possibility to predict the materials behavior beyond necking up to ductile fracture.}}, author = {{Camberg, Alan Adam and Erhart, Tobias and Tröster, Thomas}}, issn = {{1996-1944}}, journal = {{Materials}}, keywords = {{General Materials Science}}, number = {{17}}, publisher = {{MDPI AG}}, title = {{{A Generalized Stress State and Temperature Dependent Damage Indicator Framework for Ductile Failure Prediction in Heat-Assisted Forming Operations}}}, doi = {{10.3390/ma14175106}}, volume = {{14}}, year = {{2021}}, }