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 - TY - JOUR AB - We numerically simulate multiple light scattering in discrete disordered media represented by large clusters of irregular non-absorbing particles. The packing density of clusters is 0.5. With such conditions diffuse scattering is significantly reduced and light transport follows propagation channels that are determined by the particle size and topology of the medium. This kind of localization produces coherent backscattering intensity surge and enhanced negative polarization branch if compared to lower density samples. AU - Grynko, Yevgen AU - Shkuratov, Yuriy AU - Förstner, Jens ID - 17803 JF - Journal of Quantitative Spectroscopy and Radiative Transfer KW - tet_topic_scattering SN - 0022-4073 TI - Light backscattering from large clusters of densely packed irregular particles VL - 255 ER - TY - JOUR AU - Gmyr, Robert AU - Hinnenthal, Kristian AU - Kostitsyna, Irina AU - Kuhn, Fabian AU - Rudolph, Dorian AU - Scheideler, Christian AU - Strothmann, Thim ID - 17808 IS - 2 JF - Nat. Comput. TI - Forming tile shapes with simple robots VL - 19 ER - TY - JOUR AU - Hielscher, Christian AU - Grenz, Julian AU - Camberg, Alan Adam AU - Wingenbach, Nils ID - 17812 JF - ATZ - Automobiltechnische Zeitschrift SN - 0001-2785 TI - Ansatz zur effizienteren Auslegung von Hybridbauteilen ER - TY - JOUR AU - Hielscher, Christian AU - Grenz, Julian AU - Camberg, Alan Adam AU - Wingenbach, Nils ID - 17813 JF - ATZ worldwide SN - 2192-9076 TI - Approach to More Efficient Design of Hybrid Components ER - TY - GEN AB - Software verification has recently made enormous progress due to the development of novel verification methods and the speed-up of supporting technologies like SMT solving. To keep software verification tools up to date with these advances, tool developers keep on integrating newly designed methods into their tools, almost exclusively by re-implementing the method within their own framework. While this allows for a conceptual re-use of methods, it requires novel implementations for every new technique. In this paper, we employ cooperative verification in order to avoid reimplementation and enable usage of novel tools as black-box components in verification. Specifically, cooperation is employed for the core ingredient of software verification which is invariant generation. Finding an adequate loop invariant is key to the success of a verification run. Our framework named CoVerCIG allows a master verification tool to delegate the task of invariant generation to one or several specialized helper invariant generators. Their results are then utilized within the verification run of the master verifier, allowing in particular for crosschecking the validity of the invariant. We experimentally evaluate our framework on an instance with two masters and three different invariant generators using a number of benchmarks from SV-COMP 2020. The experiments show that the use of CoVerCIG can increase the number of correctly verified tasks without increasing the used resources AU - Haltermann, Jan Frederik AU - Wehrheim, Heike ID - 17825 T2 - arXiv:2008.04551 TI - Cooperative Verification via Collective Invariant Generation ER - TY - GEN ED - Werneck Richa, Andrea ED - Scheideler, Christian ID - 17836 SN - 978-3-030-54920-6 TI - Structural Information and Communication Complexity - 27th International Colloquium, SIROCCO 2020, Paderborn, Germany, June 29 - July 1, 2020, Proceedings VL - 12156 ER - TY - GEN ED - Scheideler, Christian ED - Spear, Michael ID - 17839 SN - 978-1-4503-6935-0 TI - SPAA '20: 32nd ACM Symposium on Parallelism in Algorithms and Architectures, Virtual Event, USA, July 15-17, 2020 ER - TY - CONF AU - Kersting, Joschka AU - Bäumer, Frederik Simon ID - 18686 KW - Software Requirements KW - Natural Language Processing KW - Transfer Learning KW - On-The-Fly Computing T2 - PROCEEDINGS OF THE INTERNATIONAL CONFERENCE ON APPLIED COMPUTING 2020 TI - SEMANTIC TAGGING OF REQUIREMENT DESCRIPTIONS: A TRANSFORMER-BASED APPROACH ER - TY - CHAP AU - Seng, Eva- Maria AU - Göttmann, Frank ID - 18776 T2 - Innovation in der Bauwirtschaft – Innovation in the building industry. Wesersandstein vom 16. bis 19. Jahrhundert – Weser Sandstone form the 16th to the 19th Century TI - Einleitung – Introduction ER -