@inproceedings{24017,
  abstract     = {{In developing complex technical systems, requirements are subject to continuous change. Systematic and holistic change impact analysis and proactive measures are required for reducing the number of requirement changes and their negative impact. There is no method to analyse the holistic impact of a requirement change in the context of developing complex technical systems. Holistic analysis requires to consider the local effects of requirement changes as well as effects from change propagation. To develop an approach for holistic change propagation and impact analysis, twelve performance goals are defined. Those are derived from a state of research analysis as well as an industry workshop. A three-step method is proposed. Firstly, requirement dependencies that cause change propagation are detected. Secondly, critical requirements are automatically identified based on a Page Rank algorithm. Thirdly, change impact of critical requirements is analysed based on a guideline. Validation proves that ten goals are fulfilled and two are partly fulfilled. The method addresses major shortcomings of preceding research and enables sound decision making for development engineers both before a change occurs and during decision process on a change request. This helps to reduce negative change impact in development projects and the risk of project failure.}},
  author       = {{Gräßler, Iris and Oleff, Christian and Preuß, Daniel}},
  editor       = {{Wagner, Beverly and Wilson, Juliette}},
  location     = {{Strathclyde/Glasgow}},
  title        = {{{Holistic change propagation and impact analysis in requirements management}}},
  year         = {{2021}},
}

@unpublished{26645,
  author       = {{Bobolz, Jan and Eidens, Fabian and Heitjohann, Raphael and Fell, Jeremy}},
  publisher    = {{IACR eprint}},
  title        = {{{Cryptimeleon: A Library for Fast Prototyping of Privacy-Preserving Cryptographic Schemes}}},
  year         = {{2021}},
}

@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}},
}

@techreport{33854,
  abstract     = {{Macrodiversity is a key technique to increase the capacity of mobile networks. It can be realized using coordinated multipoint (CoMP), simultaneously connecting users to multiple overlapping cells. Selecting which users to serve by how many and which cells is NP-hard but needs to happen continuously in real time as users move and channel state changes. Existing approaches often require strict assumptions about or perfect knowledge of the underlying radio system, its resource allocation scheme, or user movements, none of which is readily available in practice.

Instead, we propose three novel self-learning and self-adapting approaches using model-free deep reinforcement learning (DRL): DeepCoMP, DD-CoMP, and D3-CoMP. DeepCoMP leverages central observations and control of all users to select cells almost optimally. DD-CoMP and D3-CoMP use multi-agent DRL, which allows distributed, robust, and highly scalable coordination. All three approaches learn from experience and self-adapt to varying scenarios, reaching 2x higher Quality of Experience than other approaches. They have very few built-in assumptions and do not need prior system knowledge, making them more robust to change and better applicable in practice than existing approaches.}},
  author       = {{Schneider, Stefan Balthasar and Karl, Holger and Khalili, Ramin and Hecker, Artur}},
  keywords     = {{mobility management, coordinated multipoint, CoMP, cell selection, resource management, reinforcement learning, multi agent, MARL, self-learning, self-adaptation, QoE}},
  title        = {{{DeepCoMP: Coordinated Multipoint Using Multi-Agent Deep Reinforcement Learning}}},
  year         = {{2021}},
}

@article{21265,
  abstract     = {{<jats:p>Fast-growing energy demand of the world makes the researchers focus on finding new energy sources or optimizing already-developed approaches. For an efficient use of solar and wind energy in an energy system, correct design and sizing of a power system is of high importance and improving or optimizing the process of data obtaining for this purpose leads to higher performance and lower cost per unit of energy. It is essential to have the most precise possible estimation of solar and wind energy potential and other local weather parameters in order to fully feed the demand and avoid extra costs. There are various methods for obtaining local data, such as local measurements, official organizational data, satellite obtained, and reanalysis data. In this paper, the Modern-Era Retrospective analysis for Research and Applications dataset version 2 (MERRA-2) dataset provided by NASA is introduced and its performance is evaluated by comparison to various locally measured datasets offered by meteorological institutions such as Meteonorm and Deutscher Wetterdienst (DWD, or Germany’s National Meteorological Service) around the world. After comparison, correlation coefficients from 0.95 to 0.99 are observed for monthly global horizontal irradiance values. In the case of air temperature, correlation coefficients of 0.99 and for wind speed from 0.81 to 0.99 are observed. High correlation with ground measurements and relatively low errors are confirmed, especially for irradiance and temperature values, that makes MERRA-2 a valuable dataset, considering its world coverage and availability.</jats:p>}},
  author       = {{Khatibi, Arash and Krauter, Stefan}},
  issn         = {{1996-1073}},
  journal      = {{Energies}},
  keywords     = {{Solar irradiance, MERRA 2, Meteonorm, DWD}},
  number       = {{4}},
  publisher    = {{MDPI}},
  title        = {{{Validation and Performance of Satellite Meteorological Dataset MERRA-2 for Solar and Wind Applications}}},
  doi          = {{10.3390/en14040882}},
  volume       = {{14}},
  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{16294,
  abstract     = {{Model predictive control is a prominent approach to construct a feedback
control loop for dynamical systems. Due to real-time constraints, the major
challenge in MPC is to solve model-based optimal control problems in a very
short amount of time. For linear-quadratic problems, Bemporad et al. have
proposed an explicit formulation where the underlying optimization problems are
solved a priori in an offline phase. In this article, we present an extension
of this concept in two significant ways. We consider nonlinear problems and -
more importantly - problems with multiple conflicting objective functions. In
the offline phase, we build a library of Pareto optimal solutions from which we
then obtain a valid compromise solution in the online phase according to a
decision maker's preference. Since the standard multi-parametric programming
approach is no longer valid in this situation, we instead use interpolation
between different entries of the library. To reduce the number of problems that
have to be solved in the offline phase, we exploit symmetries in the dynamical
system and the corresponding multiobjective optimal control problem. The
results are verified using two different examples from autonomous driving.}},
  author       = {{Ober-Blöbaum, Sina and Peitz, Sebastian}},
  journal      = {{International Journal of Robust and Nonlinear Control}},
  pages        = {{380--403}},
  title        = {{{Explicit multiobjective model predictive control for nonlinear systems  with symmetries}}},
  doi          = {{10.1002/rnc.5281}},
  volume       = {{31(2)}},
  year         = {{2021}},
}

@misc{29549,
  abstract     = {{Als Griechenland 1830 seine Unabhängigkeit erlangte, war das Land wirtschaftlich wenig entwickelt und von der Industrialisierung noch kaum berührt. Kredite für die Gründung oder den Ausbau von Unternehmen waren auf Grund des Kapitalmangels entweder unmöglich oder extrem teuer – ein für die wirtschaftliche Entwicklung ernst zu nehmendes Hemmnis. Das Land brauchte zur wirtschaftlichen Entwicklung also Investitionen aus dem Ausland. Jedoch hielten sich die europäischen Banken und Anleger mit solchen Investitionen vor den 1870er Jahren zurück. Warum diese Scheu der Kapitalanleger vor Griechenland, obwohl sie anderswo keineswegs vor risikoreichen Investitionen zurückschreckten, wenn nur entsprechend hohe Erträge lockten? Dieser Frage möchte der Beitrag anhand eines Beispiels nachgehen: der bayerisch-französischen Bankiersfamilie von Eichthal, die in den 1830er Jahren enge Geschäftsbeziehungen nach Griechenland aufbaute und zeitweilig sehr interessiert an Investitionen war – bevor das Bankhaus sich von diesen Plänen schließlich unverrichteter Dinge wieder abwandte. Das kulturelle Interesse an Griechenland überdauerte dagegen bis in die 1880er Jahre. Die Eichthals eignen sich hervorragend, um paradigmatisch zu untersuchen, auf welcher Grundlage und wie europäische Bankiers ihre Investitionsentscheidungen für oder gegen Griechenland trafen.}},
  author       = {{Schönhärl, Korinna}},
  title        = {{{Finanzielle Netze. Die bayerisch–französische Familienbank von Eichthal und ihre Investitionspläne in Griechenland in den 1830er Jahren/ Οικονομικά δίκτυα. Η βαυαρογαλλική οικογενειακή τράπεζα των Άιχταλ και τα επενδυτικά σχέδιά της στην Ελλάδα κατά τη δεκαετία του 1830}}},
  year         = {{2021}},
}

@unpublished{22764,
  abstract     = {{Robotics applications process large amounts of data in real-time and require compute platforms that provide high performance and energy-efficiency. FPGAs are well-suited for many of these applications, but there is a reluctance in the robotics community to use hardware acceleration due to increased design complexity and a lack of consistent programming models across the software/hardware boundary. In this paper we present ReconROS, a framework that integrates the widely-used robot operating system (ROS) with ReconOS, which features multithreaded programming of hardware and software threads for reconfigurable computers. This unique combination gives ROS2 developers the flexibility to transparently accelerate parts of their robotics applications in hardware. We elaborate on the architecture and the design flow for ReconROS and report on a set of experiments that underline the feasibility and flexibility of our approach.}},
  author       = {{Lienen, Christian and Platzner, Marco}},
  booktitle    = {{arXiv:2107.07208}},
  pages        = {{19}},
  title        = {{{Design of Distributed Reconfigurable Robotics Systems with ReconROS}}},
  year         = {{2021}},
}

@inproceedings{25880,
  author       = {{Hetkämper, Tim and Dreiling, Dmitrij and Claes, Leander and Henning, Bernd}},
  booktitle    = {{Fortschritte der Akustik - DAGA 2021}},
  title        = {{{Tomographie des Schallfelds von Ultraschallwandlern mittels Schlierentechnik}}},
  year         = {{2021}},
}

@misc{31385,
  author       = {{Hoffmann, Max}},
  booktitle    = {{Mathematische Semesterberichte}},
  pages        = {{295–297}},
  title        = {{{Rezension: Hendrik Kasten und Denis Vogel: Grundlagen der ebenen Geometrie – Eine zugängliche aber exakte Einführung in die ebene Geometrie}}},
  doi          = {{10.1007/s00591-021-00299-3}},
  volume       = {{68}},
  year         = {{2021}},
}

@article{24955,
  author       = {{Woitkowski, David and Rochell, Leonie and Bauer, Anna}},
  issn         = {{2469-9896}},
  journal      = {{Physical Review Physics Education Research}},
  title        = {{{German university students’ views of nature of science in the introductory phase}}},
  doi          = {{10.1103/physrevphyseducres.17.010118}},
  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}},
}

@article{32560,
  abstract     = {{Several methods are available to answer questions regarding similarity and accuracy,
each of which has specific properties and limitations. This study focuses on the
Latent Congruence Model (LCM; Cheung, 2009), because of its capacity to deal
with cross-informant measurement invariance issues. Until now, no cross-national
applications of LCM are present in the literature, perhaps because of the difficulty
to deal with both cross-national and cross-informant measurement issues implied by
those models. This study presents a step-by-step procedure to apply LCM to dyadic
cross-national research designs controlling for both cross-national and cross-informant
measurement invariance. An illustrative example on parent–child support exchanges in
Italy and Germany is provided. Findings help to show the different possible scenarios
of partial invariance, and a discussion related to how to deal with those scenarios is
provided. Future perspectives in the study of parent–child similarity and accuracy in
cross-national research will be discussed.}},
  author       = {{Tagliabue, Semira and Zambelli, Michela and Sorgente, Angela and Sommer, Sabrina and Hoellger, Christian and Buhl, Heike M. and Lanz, Margherita}},
  issn         = {{1664-1078}},
  journal      = {{Frontiers in Psychology}},
  keywords     = {{latent congruence model, measurement invariance, similarity, accuracy, cross-national, cross-informant, parent-child relationship, support exchanges}},
  publisher    = {{Frontiers Media SA}},
  title        = {{{Latent Congruence Model to Investigate Similarity and Accuracy in Family Members' Perception: The Challenge of Cross-National and Cross-Informant Measurement (Non)Invariance}}},
  doi          = {{10.3389/fpsyg.2021.672383}},
  volume       = {{12}},
  year         = {{2021}},
}

@phdthesis{21502,
  abstract     = {{Die vollständige Beschreibung fluiddynamischer und akustischer Vorgänge setzt voraus, dass die Eigenschaften des Fluids hinlänglich bekannt sind.Während Fluidkenngrößen, wie etwa die Schallgeschwindigkeit oder die Scherviskosität, für viele Flüssigkeiten über weite Bereiche des thermodynamischen Zustandsraums bekannt sind, existieren für die Volumenviskosität nur eine geringe Anzahl Messdaten.In dieser Arbeit wird daher ein Messverfahren zur selektiven Bestimmung der Volumenviskosität von Flüssigkeiten, basierend auf der Absorption von Ultraschallwellen, entwickelt und realisiert.Schwerpunkte bilden dabei der simulationsgestützte Entwurf von Algorithmen zur Auswertung der Messsignale sowie die Analyse und Weiterentwicklung einer Messanordnung, basierend auf dem Puls-Echo-Verfahren. Neben der Absorption im Fluid treten dabei weitere Effekte (zum Beispiel Beugung oder unvollständige Reflexion) auf, die das akustische Signal schwächen oder anderweitig beeinflussen. Die Entwicklung von Verfahren zur Trennung dieser Effekte von der akustischen Absorption bildet daher einen weiteren Schwerpunkt dieser Arbeit.Abschließend wird die Volumenviskosität aus der gemessenen akustischen Absorption für unterschiedliche Fluide in verschiedenen thermodynamischen Zuständen unter Zuhilfenahme anderer bekannter Fluidkenngrößen bestimmt sowie eine Unsicherheitsbetrachtung durchgeführt.}},
  author       = {{Claes, Leander}},
  pages        = {{223}},
  publisher    = {{Universiät Paderborn}},
  title        = {{{Messverfahren für die akustische Absorption in reinen Fluiden zur Bestimmung der Volumenviskosität}}},
  doi          = {{10.17619/UNIPB/1-1104}},
  year         = {{2021}},
}

@article{33278,
  abstract     = {{The kinetic Brownian motion on the sphere bundle of a Riemannian manifold M is a stochastic process that models a random perturbation of the geodesic flow. If M is an orientable compact constantly curved surface, we show that in the limit of infinitely large perturbation the L2-spectrum of the infinitesimal generator of a time-rescaled version of the process converges to the Laplace spectrum of the base manifold.}},
  author       = {{Kolb, Martin and Weich, Tobias and Wolf, Lasse}},
  journal      = {{Annales Henri Poincaré }},
  number       = {{4}},
  pages        = {{1283--1296}},
  publisher    = {{Springer Science + Business Media}},
  title        = {{{Spectral Asymptotics for Kinetic Brownian Motion on Surfaces of Constant Curvature}}},
  volume       = {{23}},
  year         = {{2021}},
}

@article{33372,
  abstract     = {{<jats:p>Academics may actively respond to the expectations of the academic status market, which have largely been shaped by the World University Rankings (WURs). This study empirically examines how academics’ citation patterns have changed in response to the rise of an “evaluation environment” in academia. We regard the WURs to be a macro-level trigger for cementing a bibliometric-based evaluation environment in academia. Our analyses of citation patterns in papers published in two higher education journals explicitly considered three distinct periods: the pre-WURs (1990–2003), the period of WURs implementation (2004–2010), and the period of adaption to WURs (2011–2017). We applied the nonparametric Kaplan–Meier method to compare first-citation speeds of papers published across the three periods. We found that not only has first-citation speed become faster, but first-citation probability has also increased following the emergence of the WURs. Applying Cox proportional hazard models to first-citation probabilities, we identified journal impact factors and third-party funding as factors influencing first-citation probability, while other author- and paper-related factors showed limited effects. We also found that the general effects of different factors on first-citation speeds have changed with the emergence of the WURs. The findings expand our understanding of the citation patterns of academics in the rise of WURs and provide practical grounds for research policy as well as higher education policy.</jats:p>}},
  author       = {{Lee, Soo Jeung and Schneijderberg, Christian and Kim, Yangson and Steinhardt, Isabel}},
  issn         = {{2071-1050}},
  journal      = {{Sustainability}},
  keywords     = {{world university rankings, citation, first-citation speed, Minerva, Studies in Higher Education}},
  number       = {{17}},
  publisher    = {{MDPI AG}},
  title        = {{{Have Academics’ Citation Patterns Changed in Response to the Rise of World University Rankings? A Test Using First-Citation Speeds}}},
  doi          = {{10.3390/su13179515}},
  volume       = {{13}},
  year         = {{2021}},
}

@inbook{29292,
  author       = {{Feldhans, Robert and Wilke, Adrian and Heindorf, Stefan and Shaker, Mohammad Hossein and Hammer, Barbara and Ngonga Ngomo, Axel-Cyrille and Hüllermeier, Eyke}},
  booktitle    = {{Intelligent Data Engineering and Automated Learning – IDEAL 2021}},
  isbn         = {{9783030916077}},
  issn         = {{0302-9743}},
  publisher    = {{Springer International Publishing}},
  title        = {{{Drift Detection in Text Data with Document Embeddings}}},
  doi          = {{10.1007/978-3-030-91608-4_11}},
  year         = {{2021}},
}

@inproceedings{29287,
  abstract     = {{Knowledge graph embedding research has mainly focused on the two smallest
normed division algebras, $\mathbb{R}$ and $\mathbb{C}$. Recent results suggest
that trilinear products of quaternion-valued embeddings can be a more effective
means to tackle link prediction. In addition, models based on convolutions on
real-valued embeddings often yield state-of-the-art results for link
prediction. In this paper, we investigate a composition of convolution
operations with hypercomplex multiplications. We propose the four approaches
QMult, OMult, ConvQ and ConvO to tackle the link prediction problem. QMult and
OMult can be considered as quaternion and octonion extensions of previous
state-of-the-art approaches, including DistMult and ComplEx. ConvQ and ConvO
build upon QMult and OMult by including convolution operations in a way
inspired by the residual learning framework. We evaluated our approaches on
seven link prediction datasets including WN18RR, FB15K-237 and YAGO3-10.
Experimental results suggest that the benefits of learning hypercomplex-valued
vector representations become more apparent as the size and complexity of the
knowledge graph grows. ConvO outperforms state-of-the-art approaches on
FB15K-237 in MRR, Hit@1 and Hit@3, while QMult, OMult, ConvQ and ConvO
outperform state-of-the-approaches on YAGO3-10 in all metrics. Results also
suggest that link prediction performances can be further improved via
prediction averaging. To foster reproducible research, we provide an
open-source implementation of approaches, including training and evaluation
scripts as well as pretrained models.}},
  author       = {{Demir, Caglar and Moussallem, Diego and Heindorf, Stefan and Ngonga Ngomo, Axel-Cyrille}},
  booktitle    = {{The 13th Asian Conference on Machine Learning, ACML 2021}},
  title        = {{{Convolutional Hypercomplex Embeddings for Link Prediction}}},
  year         = {{2021}},
}