TY - GEN AB - We consider a resource-aware variant of the classical multi-armed bandit problem: In each round, the learner selects an arm and determines a resource limit. It then observes a corresponding (random) reward, provided the (random) amount of consumed resources remains below the limit. Otherwise, the observation is censored, i.e., no reward is obtained. For this problem setting, we introduce a measure of regret, which incorporates the actual amount of allocated resources of each learning round as well as the optimality of realizable rewards. Thus, to minimize regret, the learner needs to set a resource limit and choose an arm in such a way that the chance to realize a high reward within the predefined resource limit is high, while the resource limit itself should be kept as low as possible. We derive the theoretical lower bound on the cumulative regret and propose a learning algorithm having a regret upper bound that matches the lower bound. In a simulation study, we show that our learning algorithm outperforms straightforward extensions of standard multi-armed bandit algorithms. AU - Bengs, Viktor AU - Hüllermeier, Eyke ID - 21536 T2 - arXiv:2011.00813 TI - Multi-Armed Bandits with Censored Consumption of Resources ER - TY - JOUR AU - Ortmann, Regina AU - Pelster, Matthias AU - Wengerek, Sascha Tobias ID - 21539 JF - Finance Research Letters SN - 1544-6123 TI - COVID-19 and investor behavior ER - TY - CONF AB - In this publication, the near-field to far-field transformation using the self-built near-field scanner NFS3000 is examined with regard to its geometry. This device allows to measure electric and magnetic fields in small distances to the DUT (Device under Test) with high geometric precision and high sensitivity. Leading to a fast examination of EMC (Electromagnetic Compatibility) problems, because the electromagnetic properties are better understandable and therefore easier to solve than e.g. measurements in a far-field chamber. In addition, it is possible to extrapolate the near-fields into the far-field and to determine the radiation pattern of antennas and emitting objects. For this purpose, this paper deals with the basis of this transformation, the so-called surface equivalence theorem. This principle is then adapted to the measurement of near-field scanners and implemented accordingly. Due to the non-ideal design of the near-field scanner, the effects on a far-field transformation are finally presented and discussed. AU - Lange, Sven AU - Schroder, Dominik AU - Hedayat, Christian AU - Hangmann, Christian AU - Otto, Thomas AU - Hilleringmann, Ulrich ID - 21541 KW - Near-Field Scanner KW - Near-Field to Far-Field Transformation KW - Directivity KW - Surface Equivalence Theorem KW - Huygens’ Box SN - 2325-0364 T2 - 2020 International Symposium on Electromagnetic Compatibility - EMC EUROPE TI - Investigation of the Surface Equivalence Principle on a Metal Surface for a Near-Field to Far-Field Transformation by the NFS3000 ER - TY - CHAP AB - Using near-field (NF) scan data to predict the far-field (FF) behaviour of radiating electronic systems represents a novel method to accompany the whole RF design process. This approach involves so-called Huygens' box as an efficient radiation model inside an electromagnetic (EM) simulation tool and then transforms the scanned NF measured data into the FF. For this, the basic idea of the Huygens'box principle and the NF-to-FF transformation are briefly presented. The NF is measured on the Huygens' box around a device under test using anNF scanner, recording the magnitude and phase of the site-related magnetic and electric components. A comparison between a fullwave simulation and the measurement results shows a good similarity in both the NF and the simulated and transformed FF.Thus, this method is applicable to predict the FF behaviour of any electronic system by measuring the NF. With this knowledge, the RF design can be improved due to allowing a significant reduction of EM compatibility failure at the end of the development flow. In addition, the very efficient FF radiation model can be used for detailed investigations in various environments and the impact of such an equivalent radiation source on other electronic systems can be assessed. AU - Schröder, Dominik AU - Lange, Sven AU - Hangmann, Christian AU - Hedayat, Christian ID - 21542 KW - Huygens' box KW - NF-to-FF transformation KW - efficient FF radiation model KW - FF behaviour KW - EMI assessment KW - PCB KW - near-field measurements KW - efficient radiation model KW - far-field behaviour KW - RF design process KW - far-field prediction KW - Huygens'box principle KW - fullwave simulation KW - electronic system radiation KW - equivalent radiation source KW - electromagnetic simulation tool KW - near-field scan data KW - EM compatibility failure reduction SN - 9781839530494 T2 - Tensorial Analysis of Networks (TAN) Modelling for PCB Signal Integrity and EMC Analysis TI - Far-field prediction combining simulations with near-field measurements for EMI assessment of PCBs ER - TY - CHAP AU - Berger, Thomas AU - Lanza, Lukas Johannes ID - 21579 SN - 2199-7497 T2 - Progress in Differential-Algebraic Equations II TI - Observers for Differential-Algebraic Systems with Lipschitz or Monotone Nonlinearities ER - TY - CONF AU - Gatica, Carlos Paiz AU - Platzner, Marco ID - 21584 SN - 2522-8579 T2 - Machine Learning for Cyber Physical Systems (ML4CPS 2017) TI - Adaptable Realization of Industrial Analytics Functions on Edge-Devices using Reconfigurable Architectures ER - TY - JOUR AU - Meschede, Henning ID - 21608 JF - Renewable Energy SN - 0960-1481 TI - Analysis on the demand response potential in hotels with varying probabilistic influencing time-series for the Canary Islands ER - TY - JOUR AU - Graf-Schlattmann, Marcel AU - Meister, Dorothee M. AU - Oevel, Gudrun AU - Wilde, Melanie ID - 17331 IS - 1 JF - Forschungsperspektiven auf Digitalisierung in Hochschulen, Zeitschrift für Hochschulentwicklung TI - Kollektive Veränderungsbereitschaft als zentraler Erfolgsfaktor von Digitalisierungsprozessen an Hochschulen VL - 15 ER - TY - JOUR AU - Hampel, Uwe AU - Schubert, Markus AU - Döß, Alexander AU - Sohr, Johanna AU - Vishwakarma, Vineet AU - Repke, Jens‐Uwe AU - Gerke, Sören J. AU - Leuner, Hannes AU - Rädle, Matthias AU - Kapoustina, Viktoria AU - Schmitt, Lucas AU - Grünewald, Marcus AU - Brinkmann, Jost H. AU - Plate, Dominik AU - Kenig, Eugeny AU - Lutters, Nicole AU - Bolenz, Lukas AU - Buckmann, Felix AU - Toye, Dominique AU - Arlt, Wolfgang AU - Linder, Thomas AU - Hoffmann, Rainer AU - Klein, Harald AU - Rehfeldt, Sebastian AU - Winkler, Thomas AU - Bart, Hans‐Jörg AU - Wirz, Dominic AU - Schulz, Jonas AU - Scholl, Stephan AU - Augustin, Wolfgang AU - Jasch, Katharina AU - Schlüter, Florian AU - Schwerdtfeger, Natalie AU - Jahnke, Stefan AU - Jupke, Andreas AU - Kabatnik, Christoph AU - Braeuer, Andreas Siegfried AU - D'Auria, Mirko AU - Runowski, Thomas AU - Casal, Maria Francisco AU - Becker, Karsten AU - David, Anna‐Lena AU - Górak, Andrzej AU - Skiborowski, Mirko AU - Groß, Kai AU - Qammar, Hina ID - 17335 JF - Chemie Ingenieur Technik SN - 0009-286X TI - Recent Advances in Experimental Techniques for Flow and Mass Transfer Analyses in Thermal Separation Systems VL - 92 ER - TY - CHAP AU - Jazayeri, Bahar AU - Schwichtenberg, Simon AU - Küster, Jochen AU - Zimmermann, Olaf AU - Engels, Gregor ID - 17337 SN - 0302-9743 T2 - Advanced Information Systems Engineering TI - Modeling and Analyzing Architectural Diversity of Open Platforms ER - TY - CHAP AB - Peer-to-Peer news portals allow Internet users to write news articles and make them available online to interested readers. Despite the fact that authors are free in their choice of topics, there are a number of quality characteristics that an article must meet before it is published. In addition to meaningful titles, comprehensibly written texts and meaning- ful images, relevant tags are an important criteria for the quality of such news. In this case study, we discuss the challenges and common mistakes that Peer-to-Peer reporters face when tagging news and how incorrect information can be corrected through the orchestration of existing Natu- ral Language Processing services. Lastly, we use this illustrative example to give insight into the challenges of dealing with bottom-up taxonomies. AU - Bäumer, Frederik Simon AU - Kersting, Joschka AU - Buff, Bianca AU - Geierhos, Michaela ED - Audrius, Lopata ED - Rita, Butkienė ED - Daina, Gudonienė ED - Vilma, Sukackė ID - 17347 T2 - Information and Software Technologies TI - Tag Me If You Can: Insights into the Challenges of Supporting Unrestricted P2P News Tagging VL - 1283 ER - TY - CONF AU - Kucklick, Jan-Peter AU - Müller, Oliver ID - 17348 T2 - Symposium on Statistical Challenges in Electronic Commerce Research (SCECR) TI - Location, location, location: Satellite image-based real-estate appraisal ER - TY - GEN AU - Grabo, Matti AU - Staggenborg, Christoph AU - Kenig, Eugeny ID - 17349 TI - Modellierung und Optimierung makroverkapselter Latentwärmespeicherelemente für ein luftgeführtes Wärmespeichersystem ER - TY - CHAP AU - Moritzer, Elmar AU - Hüttner, Matthias AU - Henning, Bernd AU - Webersen, Manuel ED - Hopmann, Christian ED - Dahlmann, Rainer ID - 17352 SN - 9783662608081 T2 - Advances in Polymer Processing 2020 TI - The Influence of Hydrothermal Aging on the Material Properties of Continuous Fiber-Reinforced Thermoplastics and its Non-Destructive Characterization ER - TY - JOUR AB - Approximate circuits trade-off computational accuracy against improvements in hardware area, delay, or energy consumption. IP core vendors who wish to create such circuits need to convince consumers of the resulting approximation quality. As a solution we propose proof-carrying approximate circuits: The vendor creates an approximate IP core together with a certificate that proves the approximation quality. The proof certificate is bundled with the approximate IP core and sent off to the consumer. The consumer can formally verify the approximation quality of the IP core at a fraction of the typical computational cost for formal verification. In this paper, we first make the case for proof-carrying approximate circuits and then demonstrate the feasibility of the approach by a set of synthesis experiments using an exemplary approximation framework. AU - Witschen, Linus Matthias AU - Wiersema, Tobias AU - Platzner, Marco ID - 17358 IS - 9 JF - IEEE Transactions On Very Large Scale Integration Systems KW - Approximate circuit synthesis KW - approximate computing KW - error metrics KW - formal verification KW - proof-carrying hardware SN - 1063-8210 TI - Proof-carrying Approximate Circuits VL - 28 ER - TY - JOUR AB - In this article, we focus on the acceleration of a chemical reaction simulation that relies on a system of stiff ordinary differential equation (ODEs) targeting heterogeneous computing systems with CPUs and field-programmable gate arrays (FPGAs). Specifically, we target an essential kernel of the coupled chemistry aerosol-tracer transport model to the Brazilian developments on the regional atmospheric modeling system (CCATT-BRAMS). We focus on a linear solve step using the QR factorization based on the modified Gram-Schmidt method as the basis of the ODE solver in this application. We target Intel hardware accelerator research program (HARP) architecture with the OpenCL programming environment for these early experiments. Our design exploration reveals a hardware design that is up to 4 times faster than the original iterative Jacobi method used in this solver. Still, even with hardware support, the overall performance of our QR-based hardware is lower than its original software version. AU - Alberto Oliveira de Souza Junior, Carlos AU - Bispo, João AU - Cardoso, João M. P. AU - Diniz, Pedro C. AU - Marques, Eduardo ID - 17359 JF - Electronics KW - pc2-harp-ressources SN - 2079-9292 TI - Exploration of FPGA-Based Hardware Designs for QR Decomposition for Solving Stiff ODE Numerical Methods Using the HARP Hybrid Architecture ER - TY - JOUR AU - Johansson-Pajala, Rose-Marie AU - Thommes, Kirsten AU - Hoppe, Julia Amelie AU - Tuisku, Outi AU - Hennala, Lea AU - Pekkarinen, Satu AU - Melkas, Helina AU - Gustafsson, Christine ID - 17361 JF - International Journal of Social Robotics TI - Care Robot Orientation: What, Who and How? Potential Users` Perceptions ER - TY - JOUR AU - Hoppe, Julia Amelie AU - Johansson-Pajala, Rose-Marie AU - Gustafsson, Christine AU - Melkas, Helinä AU - Tusku, Outi AU - Pekkarinen, Satu AU - Hennala, Lea ID - 17366 JF - Industrie 4.0 Management SN - 2364-9208 TI - Technologieorientierung zu Assistenzrobotik – Welche Akzeptanz besteht bei der Einführung von Assistenzrobotik für die Pflege älterer Menschen? VL - 2 ER - TY - CHAP AU - Hoppe, Julia Amelie AU - Johansson-Pajala, Rose-Marie AU - Gustafsson, Christine AU - Melkas, Helinä AU - Tusku, Outi AU - Pekkarinen, Satu AU - Hennala, Lea AU - Thommes, Kirsten ED - Haltaufderheide, Joschka ED - Hovemann, Johanna ED - Vollmann, Jochen ID - 17367 T2 - Aging between Participation and Simulation - Ethical Dimensions of Socially Assistive Technologies in elderly care TI - Assistive robots in care: Expectations and perceptions of older people ER - TY - CONF AU - Vorbohle, Christian AU - Szopinski, Daniel AU - Kundisch, Dennis ED - Shishkov, B. ID - 17368 SN - 978-3-030-52305-3 TI - Business Model Dependencies: Towards conceptualizing dependencies for extending modeling languages for business models VL - 391 ER - TY - JOUR AU - Ho, Nam AU - Kaufmann, Paul AU - Platzner, Marco ID - 17369 JF - International Journal of Hybrid intelligent Systems TI - Evolution of Application-Specific Cache Mappings ER - TY - CONF AB - We consider a natural extension to the metric uncapacitated Facility Location Problem (FLP) in which requests ask for different commodities out of a finite set \( S \) of commodities. Ravi and Sinha (SODA 2004) introduced the model as the \emph{Multi-Commodity Facility Location Problem} (MFLP) and considered it an offline optimization problem. The model itself is similar to the FLP: i.e., requests are located at points of a finite metric space and the task of an algorithm is to construct facilities and assign requests to facilities while minimizing the construction cost and the sum over all assignment distances. In addition, requests and facilities are heterogeneous; they request or offer multiple commodities out of $S$. A request has to be connected to a set of facilities jointly offering the commodities demanded by it. In comparison to the FLP, an algorithm has to decide not only if and where to place facilities, but also which commodities to offer at each. To the best of our knowledge we are the first to study the problem in its online variant in which requests, their positions and their commodities are not known beforehand but revealed over time. We present results regarding the competitive ratio. On the one hand, we show that heterogeneity influences the competitive ratio by developing a lower bound on the competitive ratio for any randomized online algorithm of \( \Omega ( \sqrt{|S|} + \frac{\log n}{\log \log n} ) \) that already holds for simple line metrics. Here, \( n \) is the number of requests. On the other side, we establish a deterministic \( \mathcal{O}(\sqrt{|S|} \cdot \log n) \)-competitive algorithm and a randomized \( \mathcal{O}(\sqrt{|S|} \cdot \frac{\log n}{\log \log n} ) \)-competitive algorithm. Further, we show that when considering a more special class of cost functions for the construction cost of a facility, the competitive ratio decreases given by our deterministic algorithm depending on the function. AU - Castenow, Jannik AU - Feldkord, Björn AU - Knollmann, Till AU - Malatyali, Manuel AU - Meyer auf der Heide, Friedhelm ID - 17370 KW - Online Multi-Commodity Facility Location KW - Competitive Ratio KW - Online Optimization KW - Facility Location Problem SN - 9781450369350 T2 - Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures TI - The Online Multi-Commodity Facility Location Problem ER - TY - CONF AU - Castenow, Jannik AU - Kling, Peter AU - Knollmann, Till AU - Meyer auf der Heide, Friedhelm ID - 17371 SN - 9781450369350 T2 - Proceedings of the 32nd ACM Symposium on Parallelism in Algorithms and Architectures TI - Brief Announcement: A Discrete and Continuous Study of the Max-Chain-Formation Problem: Slow Down to Speed up ER - TY - JOUR AU - Zhou, Jiaqi AU - Khazaei, Mohammad AU - Ranjbar, Ahmad AU - Wang, Vei AU - Kühne, Thomas D. AU - Ohno, Kaoru AU - Kawazoe, Yoshiyuki AU - Liang, Yunye ID - 17375 JF - J. Mater. Chem. C TI - Modulation of nearly free electron states in hydroxyl-functionalized MXenes: a first-principles study VL - 8 ER - TY - JOUR AU - Kumar Sahoo, Sudhir AU - Heske, Julian Joachim AU - Azadi, Sam AU - Zhang, Zhenzhe AU - V Tarakina, Nadezda AU - Oschatz, Martin AU - Z. Khaliullin, Rustam AU - Antonietti, Markus AU - Kühne, Thomas ID - 17379 IS - 1 JF - Scientific Reports TI - On the Possibility of Helium Adsorption in Nitrogen Doped Graphitic Materials VL - 10 ER - TY - JOUR AU - Elgabarty, Hossam AU - Kampfrath, Tobias AU - Bonthuis, Douwe Jan AU - Balos, Vasileios AU - Kaliannan, Naveen Kumar AU - Loche, Philip AU - Netz, Roland R. AU - Wolf, Martin AU - K{\, Thomas D. AU - Sajadi, Mohsen ID - 17381 IS - 17 JF - Science Advances TI - Energy transfer within the hydrogen bonding network of water following resonant terahertz excitation VL - 6 ER - TY - JOUR AU - Rengaraj, Varadarajan AU - Lass, Michael AU - Plessl, Christian AU - Kühne, Thomas D. ID - 17382 IS - 2 JF - Computation SN - 2079-3197 TI - Accurate Sampling with Noisy Forces from Approximate Computing VL - 8 ER - TY - JOUR AU - Elgabarty, Hossam AU - Kühne, Thomas D. ID - 17384 JF - Phys. Chem. Chem. Phys. TI - Tumbling with a limp: local asymmetry in water's hydrogen bond network and its consequences VL - 22 ER - TY - JOUR AU - Kühne, Thomas D. AU - Iannuzzi, Marcella AU - Del Ben, Mauro AU - Rybkin, Vladimir V. AU - Seewald, Patrick AU - Stein, Frederick AU - Laino, Teodoro AU - Khaliullin, Rustam Z. AU - Schütt, Ole AU - Schiffmann, Florian AU - al., et ID - 17386 IS - 19 JF - The Journal of Chemical Physics SN - 1089-7690 TI - CP2K: An electronic structure and molecular dynamics software package - Quickstep: Efficient and accurate electronic structure calculations VL - 152 ER - TY - JOUR AU - Chantakit, Teanchai AU - Schlickriede, Christian AU - Sain, Basudeb AU - Meyer, Fabian AU - Weiss, Thomas AU - Chattham, Nattaporn AU - Zentgraf, Thomas ID - 17390 IS - 9 JF - Photonics Research SN - 2327-9125 TI - All-dielectric silicon metalens for two-dimensional particle manipulation in optical tweezers VL - 8 ER - TY - CONF AU - Turcanu, Ion AU - Engel, Thomas AU - Sommer, Christoph ID - 17398 SN - 9781728145716 T2 - 2019 IEEE Vehicular Networking Conference (VNC) TI - Fog Seeding Strategies for Information-Centric Heterogeneous Vehicular Networks ER - TY - CONF AU - Frank, Maximilian AU - Gausemeier, Juergen AU - Hennig-Cardinal von Widdern, Nils AU - Koldewey, Christian AU - Menzefricke, Joern Steffen AU - Reinhold, Jannik ID - 17405 T2 - Proceedings of the ISPIM connects TI - A reference process for the Smart Service business: development and practical implications ER - TY - CONF AU - Becker, Julia-Kristin AU - Joachim, Klemens AU - Koldewey, Christian AU - Reinhold, Jannik AU - Dumitrescu, Roman ID - 17406 T2 - Proceedings of the 2020 ISPIM Innovation Conference (Virtual) Event "Innovating in Times of Crisis" TI - Scaling Digital Business Models: A Case from the Automotive Industry ER - TY - CONF AU - Tornede, Alexander AU - Wever, Marcel Dominik AU - Hüllermeier, Eyke ID - 17407 T2 - Discovery Science TI - Extreme Algorithm Selection with Dyadic Feature Representation ER - TY - CONF AU - Hanselle, Jonas Manuel AU - Tornede, Alexander AU - Wever, Marcel Dominik AU - Hüllermeier, Eyke ID - 17408 T2 - KI 2020: Advances in Artificial Intelligence TI - Hybrid Ranking and Regression for Algorithm Selection ER - TY - CHAP AB - Many dynamical systems possess symmetries, e.g. rotational and translational invariances of mechanical systems. These can be beneficially exploited in the design of numerical optimal control methods. We present a model predictive control scheme which is based on a library of precomputed motion primitives. The primitives are equivalence classes w.r.t. the symmetry of the optimal control problems. Trim primitives as relative equilibria w.r.t. this symmetry, play a crucial role in the algorithm. The approach is illustrated using an academic mobile robot example. AU - Flaßkamp, Kathrin AU - Ober-Blöbaum, Sina AU - Peitz, Sebastian ED - Junge, Oliver ED - Schütze, Oliver ED - Froyland, Gary ED - Ober-Blöbaum, Sina ED - Padberg-Gehle, Kathrin ID - 17411 SN - 2198-4182 T2 - Advances in Dynamics, Optimization and Computation TI - Symmetry in Optimal Control: A Multiobjective Model Predictive Control Approach ER - TY - CONF AU - Tornede, Tanja AU - Tornede, Alexander AU - Wever, Marcel Dominik AU - Mohr, Felix AU - Hüllermeier, Eyke ID - 17424 T2 - Proceedings of the ECMLPKDD 2020 TI - AutoML for Predictive Maintenance: One Tool to RUL Them All ER - TY - JOUR AB - The development of renewable energies and smart mobility has profoundly impacted the future of the distribution grid. An increasing bidirectional energy flow stresses the assets of the distribution grid, especially medium voltage switchgear. This calls for improved maintenance strategies to prevent critical failures. Predictive maintenance, a maintenance strategy relying on current condition data of assets, serves as a guideline. Novel sensors covering thermal, mechanical, and partial discharge aspects of switchgear, enable continuous condition monitoring of some of the most critical assets of the distribution grid. Combined with machine learning algorithms, the demands put on the distribution grid by the energy and mobility revolutions can be handled. In this paper, we review the current state-of-the-art of all aspects of condition monitoring for medium voltage switchgear. Furthermore, we present an approach to develop a predictive maintenance system based on novel sensors and machine learning. We show how the existing medium voltage grid infrastructure can adapt these new needs on an economic scale. AU - Hoffmann, Martin W. AU - Wildermuth, Stephan AU - Gitzel, Ralf AU - Boyaci, Aydin AU - Gebhardt, Jörg AU - Kaul, Holger AU - Amihai, Ido AU - Forg, Bodo AU - Suriyah, Michael AU - Leibfried, Thomas AU - Stich, Volker AU - Hicking, Jan AU - Bremer, Martin AU - Kaminski, Lars AU - Beverungen, Daniel AU - zur Heiden, Philipp AU - Tornede, Tanja ID - 17426 JF - Sensors SN - 1424-8220 TI - Integration of Novel Sensors and Machine Learning for Predictive Maintenance in Medium Voltage Switchgear to Enable the Energy and Mobility Revolutions ER - TY - JOUR AU - Wang, D. Q. AU - Reuter, Dirk AU - Wieck, A. D. AU - Hamilton, A. R. AU - Klochan, O. ID - 17433 JF - Applied Physics Letters SN - 0003-6951 TI - Two-dimensional lateral surface superlattices in GaAs heterostructures with independent control of carrier density and modulation potential ER - TY - JOUR AU - Kunnathully, Vinay S. AU - Riedl, Thomas AU - Trapp, Alexander AU - Langer, Timo AU - Reuter, Dirk AU - Lindner, Jörg K.N. ID - 17434 JF - Journal of Crystal Growth SN - 0022-0248 TI - InAs heteroepitaxy on nanopillar-patterned GaAs (111)A ER - TY - JOUR AU - Geier, M. AU - Freudenfeld, J. AU - Silva, J. T. AU - Umansky, V. AU - Reuter, Dirk AU - Wieck, A. D. AU - Brouwer, P. W. AU - Ludwig, S. ID - 17435 JF - Physical Review B SN - 2469-9950 TI - Electrostatic potential shape of gate-defined quantum point contacts ER - TY - JOUR AB - The study of electron transport in low-dimensional systems is of importance, not only from a fundamental point of view, but also for future electronic and spintronic devices. In this context heterostructures containing a two-dimensional electron gas (2DEG) are a key technology. In particular GaAs/AlGaAs heterostructures, with a 2DEG at typically 100 nm below the surface, are widely studied. In order to explore electron transport in such systems, low-resistance ohmic contacts are required that connect the 2DEG to macroscopic measurement leads at the surface. Here we report on designing and measuring a dedicated device for unraveling the various resistance contributions in such contacts, which include pristine 2DEG series resistance, the 2DEG resistance under a contact, the contact resistance itself, and the influence of pressing a bonding wire onto a contact. We also report here a recipe for contacts with very low resistance values that remain below 10 Ω for annealing times between 20 and 350 s, hence providing the flexibility to use this method for materials with different 2DEG depths. The type of heating, temperature ramp rate and gas forming used for annealing is found to strongly influence the annealing process and hence the quality of the resulting contacts. AU - Javaid Iqbal, Muhammad AU - Reuter, Dirk AU - Wieck, Andreas Dirk AU - van der Wal, Caspar ID - 17436 JF - The European Physical Journal Applied Physics SN - 1286-0042 TI - Characterization of low-resistance ohmic contacts to a two-dimensional electron gas in a GaAs/AlGaAs heterostructure ER - TY - JOUR AU - Ebler, C. AU - Labud, P. A. AU - Rai, A. K. AU - Reuter, Dirk AU - Wieck, A. D. AU - Ludwig, A. ID - 17437 JF - Physical Review B SN - 2469-9950 TI - Electrical detection of excitonic states by time-resolved conductance measurements ER - TY - JOUR AB - Compact and robust cold atom sources are increasingly important for quantum research, especially for transferring cutting-edge quantum science into practical applications. In this study, we report on a novel scheme that uses a metasurface optical chip to replace the conventional bulky optical elements used to produce a cold atomic ensemble with a single incident laser beam, which is split by the metasurface into multiple beams of the desired polarization states. Atom numbers ~107 and temperatures (about 35 μK) of relevance to quantum sensing are achieved in a compact and robust fashion. Our work highlights the substantial progress toward fully integrated cold atom quantum devices by exploiting metasurface optical chips, which may have great potential in quantum sensing, quantum computing, and other areas. AU - Zhu, Lingxiao AU - Liu, Xuan AU - Sain, Basudeb AU - Wang, Mengyao AU - Schlickriede, Christian AU - Tang, Yutao AU - Deng, Junhong AU - Li, Kingfai AU - Yang, Jun AU - Holynski, Michael AU - Zhang, Shuang AU - Zentgraf, Thomas AU - Bongs, Kai AU - Lien, Yu-Hung AU - Li, Guixin ID - 17523 IS - 31 JF - Science Advances SN - 2375-2548 TI - A dielectric metasurface optical chip for the generation of cold atoms VL - 6 ER - TY - JOUR AU - Schweizer, Swetlana AU - Becker-Staines, Anna AU - Tröster, Thomas ID - 17578 JF - Waste Management SN - 0956-053X TI - Separation and reclamation of automotive hybrid structures made of metal and fibre-reinforced plastic ER - TY - JOUR AU - Sonnenrein, G. AU - Baumhögger, Elmar AU - Elsner, A. AU - Morbach, A. AU - Neukötter, M. AU - Paul, A. AU - Vrabec, J. ID - 17589 JF - International Journal of Refrigeration SN - 0140-7007 TI - Improving the performance of household refrigerating appliances through the integration of phase change materials in the context of the new global refrigerator standard IEC 62552:2015 ER - TY - GEN AB - Syntactic annotation of corpora in the form of part-of-speech (POS) tags is a key requirement for both linguistic research and subsequent automated natural language processing (NLP) tasks. This problem is commonly tackled using machine learning methods, i.e., by training a POS tagger on a sufficiently large corpus of labeled data. While the problem of POS tagging can essentially be considered as solved for modern languages, historical corpora turn out to be much more difficult, especially due to the lack of native speakers and sparsity of training data. Moreover, most texts have no sentences as we know them today, nor a common orthography. These irregularities render the task of automated POS tagging more difficult and error-prone. Under these circumstances, instead of forcing the POS tagger to predict and commit to a single tag, it should be enabled to express its uncertainty. In this paper, we consider POS tagging within the framework of set-valued prediction, which allows the POS tagger to express its uncertainty via predicting a set of candidate POS tags instead of guessing a single one. The goal is to guarantee a high confidence that the correct POS tag is included while keeping the number of candidates small. In our experimental study, we find that extending state-of-the-art POS taggers to set-valued prediction yields more precise and robust taggings, especially for unknown words, i.e., words not occurring in the training data. AU - Heid, Stefan Helmut AU - Wever, Marcel Dominik AU - Hüllermeier, Eyke ID - 17605 T2 - Journal of Data Mining and Digital Humanities TI - Reliable Part-of-Speech Tagging of Historical Corpora through Set-Valued Prediction ER - TY - GEN AB - Employing a unique sample of 2,849 tariff imposition announcements by and against the United States (U.S.) over the period from 2018 to 2019, this study analyzes the impact of recent tariff announcements on share prices from 859 U.S. companies. We provide evidence for negative (cumulative) average abnormal stock returns due to tariff announcements during a symmetric three-day event window. We suggest that stock market investors expect adverse impacts of tariff impositions, e.g. a decrease in the companies' future cash flows and a threat of retaliation. The negative wealth effects are observed irrespective of whether the Trump administration announces safeguard tariffs to protect domestic firms or a retaliation is declared by foreign countries. Moreover, building several subsamples, we find that the adverse impact is mostly driven by announcements involving China and is associated with a variety of sector, tariff, trade and firm characteristics. AU - Wengerek, Sascha Tobias ID - 17703 KW - event study KW - international relations KW - protectionism KW - strategic trade policy KW - tariffs KW - trade conflict TI - Share price reactions to tariff imposition announcements in the Trump era - An event study of the trade conflict ER - TY - JOUR AU - Ortmann, Regina AU - Pelster, Matthias AU - Wengerek, Sascha Tobias ID - 17730 JF - Finance Research Letters SN - 1544-6123 TI - COVID-19 and investor behavior VL - 37 ER - TY - CONF AU - Haeb-Umbach, Reinhold ED - Böck, Ronald ED - Siegert, Ingo ED - Wendemuth, Andreas ID - 17763 KW - Poster SN - 978-3-959081-93-1 T2 - Studientexte zur Sprachkommunikation: Elektronische Sprachsignalverarbeitung 2020 TI - Sprachtechnologien für Digitale Assistenten ER -