@article{34786,
abstract = {{A locally compact contraction group is a pair (G,α), where G is a locally compact group and α:G→G an automorphism such that αn(x)→e pointwise as n→∞. We show that every surjective, continuous, equivariant homomorphism between locally compact contraction groups admits an equivariant continuous global section. As a consequence, extensions of locally compact contraction groups with abelian kernel can be described by continuous equivariant cohomology. For each prime number p, we use 2-cocycles to construct uncountably many pairwise non-isomorphic totally disconnected, locally compact contraction groups (G,α) which are central extensions0→Fp((t))→G→Fp((t))→0 of the additive group of the field of formal Laurent series over Fp=Z/pZ by itself. By contrast, there are only countably many locally compact contraction groups (up to isomorphism) which are torsion groups and abelian, as follows from a classification of the abelian locally compact contraction groups.}},
author = {{Glöckner, Helge and Willis, George A.}},
issn = {{0021-8693}},
journal = {{Journal of Algebra}},
keywords = {{Contraction group, Torsion group, Extension, Cocycle, Section, Equivariant cohomology, Abelian group, Nilpotent group, Isomorphism types}},
pages = {{164--214}},
title = {{{Decompositions of locally compact contraction groups, series and extensions}}},
doi = {{https://doi.org/10.1016/j.jalgebra.2020.11.007}},
volume = {{570}},
year = {{2021}},
}
@article{34795,
author = {{Glöckner, Helge}},
issn = {{0025-584X}},
journal = {{Mathematische Nachrichten}},
number = {{1}},
pages = {{74–81}},
title = {{{Direct limits of regular Lie groups}}},
doi = {{10.1002/mana.201900073}},
volume = {{294}},
year = {{2021}},
}
@unpublished{34806,
abstract = {{Let $G$ be a Lie group over a totally disconnected local field and $\alpha$
be an analytic endomorphism of $G$. The contraction group of $\alpha$ ist the
set of all $x\in G$ such that $\alpha^n(x)\to e$ as $n\to\infty$. Call sequence
$(x_{-n})_{n\geq 0}$ in $G$ an $\alpha$-regressive trajectory for $x\in G$ if
$\alpha(x_{-n})=x_{-n+1}$ for all $n\geq 1$ and $x_0=x$. The anti-contraction
group of $\alpha$ is the set of all $x\in G$ admitting an $\alpha$-regressive
trajectory $(x_{-n})_{n\geq 0}$ such that $x_{-n}\to e$ as $n\to\infty$. The
Levi subgroup is the set of all $x\in G$ whose $\alpha$-orbit is relatively
compact, and such that $x$ admits an $\alpha$-regressive trajectory
$(x_{-n})_{n\geq 0}$ such that $\{x_{-n}\colon n\geq 0\}$ is relatively
compact. The big cell associated to $\alpha$ is the set $\Omega$ of all all
products $xyz$ with $x$ in the contraction group, $y$ in the Levi subgroup and
$z$ in the anti-contraction group. Let $\pi$ be the mapping from the cartesian
product of the contraction group, Levi subgroup and anti-contraction group to
$\Omega$ which maps $(x,y,z)$ to $xyz$. We show: $\Omega$ is open in $G$ and
$\pi$ is \'{e}tale for suitable immersed Lie subgroup structures on the three
subgroups just mentioned. Moreover, we study group-theoretic properties of
contraction groups and anti-contraction groups.}},
author = {{Glöckner, Helge}},
booktitle = {{arXiv:2101.02981}},
title = {{{Contraction groups and the big cell for endomorphisms of Lie groups over local fields}}},
year = {{2021}},
}
@phdthesis{28683,
abstract = {{In den letzten Jahren haben sich Software-Ökosysteme als neue, erfolgreiche Geschäftsform etabliert. Unternehmen agieren hierbei als Anbieter von Software-Plattformen, auf denen Drittanbieter Softwarelösungen für den Markt anbieten können. Etablierte Beispiele sind hierbei sogenannte App-Stores, die z.B. von Google oder Apple angeboten werden.
Beim Aufbau von Software-Ökosystemen müssen vom Plattformanbieter viele architektonische Entwurfsentscheidungen getroffen werden. Bisher gibt es keine Architekturrichtlinien und -werkzeuge, die den Entwurf einer Ökosystemarchitektur unterstützen. Dadurch fehlt hier systematisches, wiederverwendbares Wissen. Plattformanbieter müssen auf ad-hoc Entscheidungen zurückgreifen. Dies kann dann zu Problemen im Betrieb der Software-Plattformen führen, zu erhöhten Ausfallrisiken und Mehrkosten.
Der Mangel an Architekturwissen manifestiert sich konkret in zwei Gruppen von Herausforderungen: Erstens fehlt eine Wissensbasis zu Architekturalternativen und zweitens fehlt es an methodischem Wissen zu Entwicklung und Betrieb von Software-Ökosystemen. Eine Architekturwissensbasis würde Orientierungshilfen zu den Bestandteilen von Software-Ökosystemen und deren Abhängigkeiten geben, während methodisches Wissen die Erstellung dieser Systeme erleichtern würde.
In der Dissertation werden diese Herausforderungen durch die Entwicklung des Frameworks SecoArc für die Modellierung von Software-Ökosystemen angegangen. Der Beitrag der Dissertation ist zweifach:
1. Das SecoArc-Framework umfasst eine Architekturwissensbasis, die wiederverwendbare Architekturentwurfsentscheidungen
von Software-Ökosystemen enthält. Die Wissensbasis wurde entwickelt, indem das Architekturwissen bestehender Ökosysteme sowie aus existierender Fachliteratur ermittelt wurde und in einer Produktlinie für Software-Ökosysteme konsolidiert wurde. Die Produktlinie umfasst architektonische Gemeinsamkeiten und Variabilitäten von Software-Ökosystemen.
2. Das SecoArc-Framework liefert methodisches Wissen, um die Ökosystemarchitektur in Modellen zu entwerfen und zu analysieren. Dieses Wissen wurde entwickelt, indem drei Architekturmuster identifiziert wurden. Jedes Muster erfasst unterschiedliche Beziehungen zwischen architektonischen Entwurfsentscheidungen zu den Qualitätsmerkmalen einer Ökosystemgesundheit und der Erreichung von Geschäftszielen.
Die Architekturmuster und die Produktlinie wurden dazu genutzt, ein Modellierungsframework zu entwickeln und in Form eines Prototypen umzusetzen, welches einen Entwurfsprozess, eine Modellierungssprache und eine Architekturanalysetechnik umfasst. Es erleichtert das Modellieren, Analysieren und Vergleichen von Ökosystemarchitekturen.
Die Ergebnisse der Dissertation wurden im Rahmen von zwei Studien evaluiert. In der ersten Validierungsstudie wurden das Framework sowie der Prototyp verwendet, um zwei alternative Ökosystemarchitekturen zu entwerfen und zu analysieren. In der zweiten Studie wurde eine Analyse von existierenden Ökosystemen basierend auf den architektonischen Variabilitäten des Frameworks durchgeführt.}},
author = {{Schwichtenberg, Bahar}},
keywords = {{Enterprise Architecture, Architectural Design Decisions, Open Platforms}},
title = {{{Modeling and Analyzing Software Ecosystems}}},
doi = {{10.17619/UNIPB/1-1270 }},
year = {{2021}},
}
@inproceedings{24551,
abstract = {{Access to precise meteorological data is crucial to be able to plan and install renewable energy systems
such as solar power plants and wind farms. In case of solar energy, knowledge of local irradiance and air temperature
values is very important. For this, various methods can be used such as installing local weather stations or using
meteorological data from different organizations such as Meteonorm or official Deutscher Wetterdienst (DWD). An
alternative is to use satellite reanalysis datasets provided by organizations like the National Aeronautics and Space
Administration (NASA) and European Centre for Medium-Range Weather Forecasts (ECMWF). In this paper the
“Modern-Era Retrospective analysis for Research and Applications” dataset version 2 (MERRA-2) will be presented,
and its performance will be evaluated by comparing it to locally measured datasets provided by Meteonorm and DWD.
The analysis shows very high correlation between MERRA-2 and local measurements (correlation coefficients of 0.99)
for monthly global irradiance and air temperature values. The results prove the suitability of MERRA-2 data for
applications requiring long historical data. Moreover, availability of MERRA-2 for the whole world with an acceptable
resolution makes it a very valuable dataset.}},
author = {{Khatibi, Arash and Krauter, Stefan}},
booktitle = {{Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EUPVSEC 2021)}},
isbn = {{3-936338-78-7}},
keywords = {{Energy potential estimation, Photovoltaic, Solar radiation, Temperature measurement, Satellite data, Meteonorm, MERRA-2, DWD}},
pages = {{1141 -- 1147}},
title = {{{Comparison and Validation of Irradiance Data: Satellite Meteorological Dataset MERRA-2 vs. Meteonorm and German Weather Service (DWD)}}},
doi = {{10.4229/EUPVSEC20212021-5BV.4.11}},
year = {{2021}},
}
@inproceedings{24550,
abstract = {{Efficiencies and energy yields of microinverters available on the market during 2014‒2021 have been
measured, compared, and ranked. Conversion efficiencies as a function of load have been measured indoors with high
accuracy and ranked according to Euro- and CEC weightings. Energy yields have been measured outdoors via
identical and calibrated crystalline silicon PV modules of 215 Wp (until 2020) and 360 Wp (starting 2021). Inverters
with two inputs have been fed by two of those modules. DC input, AC power output and energy yield of each microinverter have been recorded by individual calibrated electricity meters. CEC and EU efficiency rankings have been
computed and compared. To assess the influence of PV module size, two extremes have been investigated: A rather
small module with 215 Wp - as it has been used 10 years ago, and a brand-new module (2021) offering 360 Wp. Both
types of modules contain 60 solar cells in series connection. Appling the low-power modules, the challenge for the
different micro-inverters has been during weak-light conditions, using the high-power modules, some inverters
temporarily reach their power limits and yield is reduced. A method using a reference configuration of inverter &
module and a linear equation y = ax + b resulting in the actual yield, any module & inverter configuration can be
characterized by just the coefficients a and b.}},
author = {{Krauter, Stefan and Bendfeld, Jörg}},
booktitle = {{Proceedings of the 38th European Photovoltaic Solar Energy Conference and Exhibition (EU PVSEC 2021)}},
isbn = {{3-936338-78-7}},
keywords = {{AC-modules, Microinverter, Power Conditioning, Efficiency, Yield, PV module size, saturation, performance}},
pages = {{659 -- 663}},
title = {{{Module-Inverters (Microinverters): Influence of Module Size on Conversion Efficiencies and Energy Yields}}},
doi = {{10.4229/EUPVSEC20212021-4CO.3.4}},
year = {{2021}},
}
@article{21265,
abstract = {{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.}},
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}},
}
@inproceedings{26986,
author = {{Castenow, Jannik and Götte, Thorsten and Knollmann, Till and Meyer auf der Heide, Friedhelm}},
booktitle = {{Proceedings of the 23rd International Symposium on Stabilization, Safety, and Security of Distributed Systems, SSS 2021}},
editor = {{Johnen, C. and Schiller, E.M. and Schmid, S.}},
location = {{Online}},
pages = {{289--304 }},
publisher = {{Springer}},
title = {{{The Max-Line-Formation Problem – And New Insights for Gathering and Chain-Formation}}},
doi = {{10.1007/978-3-030-91081-5_19}},
volume = {{13046}},
year = {{2021}},
}
@article{29210,
abstract = {{This paper investigates an ultra-broadband sampling technique based on charge sampling using an Integrate-and-Hold Circuit (IHC) and ultra-short integration times. The charge sampling technique is mathematically analyzed in detail and compared to conventional switched-capacitor sampling. The mathematical analysis allows to predict the sampler bandwidth as well as the degradation of sampling precision due to analog circuit impairments such as integrator gain error, integration capacitor leakage, hold-mode droop, thermal noise, and clock jitter. Furthermore, design, simulation, and measurement results of an ultra-broadband charge sampler IC in SiGe BiCMOS technology are presented. The charge sampler IC achieves a 1dB bandwidth of 70 GHz. A resolution of better than 5.9 effective number of bits (ENOB) is measured from 0 to 70 GHz at a sampling rate of 5 GS/s. The results suggest that charge sampling using an IHC is a viable concept for ultra-broadband sampling.}},
author = {{Wu, Liang and Scheytt, J. Christoph}},
issn = {{1549-8328}},
journal = {{IEEE Transactions on Circuits and Systems I: Regular Papers}},
keywords = {{Electrical and Electronic Engineering}},
number = {{9}},
pages = {{3668--3681}},
publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}},
title = {{{Analysis and Design of a Charge Sampler With 70-GHz 1-dB Bandwidth in 130-nm SiGe BiCMOS}}},
doi = {{10.1109/tcsi.2021.3094428}},
volume = {{68}},
year = {{2021}},
}
@inproceedings{29217,
abstract = {{The circuit design and measurement results of a mixed-signal receiver baseband circuit for a wireless high data rate communication system are presented. The circuit design of the two most important system blocks of the sliced receiver baseband architecture, namely the broadband, programmable code-generator circuit, and the integrate and dump correlator circuit are explained. Using parallel sequence spread spectrum (PSSS) with PAM-4 modulated data, a net data rate of 2.22 Gbps is demonstrated with a single receiver baseband slice circuit working with a chip rate of 20 Gcps. A total of 15 slices are required to recover all 15 parallelly transmitted symbols resulting in the net data rate of 33.33 Gbps. This is the first reported implementation of a mixed-signal PSSS baseband circuit.}},
author = {{Javed, Abdul Rehman and Scheytt, J. Christoph}},
booktitle = {{2021 IEEE International Midwest Symposium on Circuits and Systems (MWSCAS)}},
publisher = {{IEEE}},
title = {{{Mixed-Signal Receiver Baseband Slice for High-Data-Rate Communication Using 130 nm SiGe BiCMOS Technology}}},
doi = {{10.1109/MWSCAS47672.2021.9531711}},
year = {{2021}},
}
@inproceedings{29221,
abstract = {{An m-sequence radar with a high chip rate of 20 Gcps is presented that makes use of the large bandwidth available in the V-band (40-75 GHz) or at 240 GHz to reduce the detection resolution to 7.5 mm. Measurement results of a mixed-signal radar receiver baseband (BB) integrated circuit designed using 130 nm SiGe BiCMOS technology are presented along with a novel radar ranging concept for the mixed-signal radar BB.}},
author = {{Javed, Abdul Rehman and Scheytt, J. Christoph}},
booktitle = {{2020 17th European Radar Conference (EuRAD)}},
publisher = {{IEEE}},
title = {{{M-Sequence Radar for High Resolution Ranging with Mixed-Signal Radar Receiver Baseband Using 130nm SiGe BiCMOS Technology}}},
doi = {{10.1109/EuRAD48048.2021.00029}},
year = {{2021}},
}
@inproceedings{28256,
author = {{Zhang, Wangyou and Boeddeker, Christoph and Watanabe, Shinji and Nakatani, Tomohiro and Delcroix, Marc and Kinoshita, Keisuke and Ochiai, Tsubasa and Kamo, Naoyuki and Haeb-Umbach, Reinhold and Qian, Yanmin}},
booktitle = {{ICASSP 2021 - 2021 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)}},
title = {{{End-to-End Dereverberation, Beamforming, and Speech Recognition with Improved Numerical Stability and Advanced Frontend}}},
doi = {{10.1109/icassp39728.2021.9414464}},
year = {{2021}},
}
@inproceedings{28262,
author = {{Li, Chenda and Shi, Jing and Zhang, Wangyou and Subramanian, Aswin Shanmugam and Chang, Xuankai and Kamo, Naoyuki and Hira, Moto and Hayashi, Tomoki and Boeddeker, Christoph and Chen, Zhuo and Watanabe, Shinji}},
booktitle = {{2021 IEEE Spoken Language Technology Workshop (SLT)}},
title = {{{ESPnet-SE: End-To-End Speech Enhancement and Separation Toolkit Designed for ASR Integration}}},
doi = {{10.1109/slt48900.2021.9383615}},
year = {{2021}},
}
@inproceedings{28261,
author = {{Li, Chenda and Luo, Yi and Han, Cong and Li, Jinyu and Yoshioka, Takuya and Zhou, Tianyan and Delcroix, Marc and Kinoshita, Keisuke and Boeddeker, Christoph and Qian, Yanmin and Watanabe, Shinji and Chen, Zhuo}},
booktitle = {{2021 IEEE Spoken Language Technology Workshop (SLT)}},
title = {{{Dual-Path RNN for Long Recording Speech Separation}}},
doi = {{10.1109/slt48900.2021.9383514}},
year = {{2021}},
}
@article{27367,
abstract = {{An approach for the non-destructive characterisation of adhesive bonds using guided ultrasonic waves is presented. Pulsed laser radiation is used to thermoacoustically excite broadband ultrasonic waves in a multi-layered sample, consisting of a metal plate adhesively joined to a polymeric layer using synthetic resin. The resulting signals are received by a purpose-built piezoelectric transducer. Varying the distance between excitation and detection yields spatio-temporal measurement data, from which the dispersive properties of the propagating waves can be inferred using a two-dimensional Fourier transform, assuming the plates to act as coupled waveguides. Coupled multi-layered waveguides show an effect referred to as mode repulsion, where the distance between certain modes in the frequency-wavenumber domain is assumed to be a measure of coupling strength. Measurements at different stages of curing of the adhesive layer are performed and evaluated. A comparison of the results shows changes in the dispersive properties, namely an increased modal bandwidth for the fully cured sample as well as an increased modal distance.}},
author = {{Zeipert, Henning and Claes, Leander and Johannesmann, Sarah and Lugovtsova, Yevgeniya and Nicolai, Marcel and Prager, Jens and Henning, Bernd}},
issn = {{2196-677X}},
journal = {{at - Automatisierungstechnik}},
pages = {{962--969}},
title = {{{An approach to adhesive bond characterisation using guided acoustic waves in multi-layered plates}}},
doi = {{10.1515/auto-2021-0089}},
year = {{2021}},
}
@inproceedings{29486,
author = {{Firmansyah, Asep Fajar and Moussallem, Diego and Ngonga Ngomo, Axel-Cyrille}},
booktitle = {{Proceedings of the 11th on Knowledge Capture Conference}},
isbn = {{978-1-4503-8457-5}},
pages = {{73–80}},
publisher = {{ACM}},
title = {{{GATES: Using Graph Attention Networks for Entity Summarization}}},
doi = {{10.1145/3460210.3493574}},
year = {{2021}},
}
@inproceedings{29421,
author = {{Ober-Blöbaum, Sina and Vermeeren, M.}},
booktitle = {{7th IIFAC Workshop on Lagrangian and Hamiltonian Methods for Nonlinear Control LHMNC}},
pages = {{327--333}},
title = {{{Superconvergence of galerkin variational integrators}}},
volume = {{54(19)}},
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}},
}
@article{29543,
author = {{Djema, Walid and Giraldi, Laetitia and Maslovskaya, Sofya and Bernard, Olivier}},
issn = {{0005-1098}},
journal = {{Automatica}},
keywords = {{Electrical and Electronic Engineering, Control and Systems Engineering}},
publisher = {{Elsevier BV}},
title = {{{Turnpike features in optimal selection of species represented by quota models}}},
doi = {{10.1016/j.automatica.2021.109804}},
volume = {{132}},
year = {{2021}},
}
@inproceedings{29566,
author = {{Bobolz, Jan and Eidens, Fabian and Krenn, Stephan and Ramacher, Sebastian and Samelin, Kai}},
booktitle = {{Cryptology and Network Security}},
isbn = {{9783030925475}},
issn = {{0302-9743}},
publisher = {{Springer International Publishing}},
title = {{{Issuer-Hiding Attribute-Based Credentials}}},
doi = {{10.1007/978-3-030-92548-2_9}},
year = {{2021}},
}