@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{29213, abstract = {{This paper presents a technique to extend the frequency acquisition range for bang-bang phase-detector-based clock and data recovery (CDR) circuits without an additional frequency acquisition loop or lock detection circuit. The per-manent modulation of the offset current in the CDR's integral branch enhances the acquisition range by nearly 4 times, covering the entire tuning range of the voltage controlled oscillator. The increase in power dissipation and the chip area are negligible. This technique was implemented and measured in a 28 Gbps NRZ bang-bang CDR chip to confirm the working principle. In addition to the increased acquisition range, the CDR also surpasses jitter related specifications from the OIF CEI-28G-VSR standard.}}, author = {{Iftekhar, Mohammed and Gudyriev, Sergiy and Scheytt, J. Christoph}}, booktitle = {{The 2021 IEEE BiCMOS and Compound Semiconductor Integrated Circuits and Technology Symposium}}, title = {{{Reference-less Bang-bang CDR with Enhanced Frequency Acquisition Range Using Static and Modulated Integral Branch Offset Currents}}}, doi = {{10.1109/BCICTS50416.2021.9682207}}, 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}}, } @inproceedings{25265, abstract = {{Waveguide-based methods can be used for the non-destructive determination of acoustic material parameters. One of these methods is based on transmission measurements of cylindrical polymeric specimens. Here, the experimental setup consists of two transducers, which excite and receive the waveguide modes at the faces of the cylinder. The measurement, as well as a forward model, are used to determine material parameters of the polymeric specimen in an inverse approach. 1-3 piezoelectric composites are used as an active element because they can be approximated by a thickness vibration only. This allows an easy identification of Mason model parameters to characterise the transducers’ vibration behaviour. However, sensitivity analysis shows a high uncertainty in the determination of the mechanical shear parameters due to the uniform excitation. To increase the sensitivity to these shear motions, arbitrary excitations were investigated by means of numerical simulation. In order to be able to realise the determined optimal excitation, new transducer prototypes were designed. By subdividing the electrodes of the active element, for example, ring-shaped excitation is feasible. Furthermore, it can be shown that modelling these transducers with a one-dimensional Mason model is sufficient.}}, author = {{Dreiling, Dmitrij and Itner, Dominik and Feldmann, Nadine and Scheidemann, Claus and Gravenkamp, Hauke and Henning, Bernd}}, booktitle = {{Fortschritte der Akustik - DAGA 2021}}, location = {{Wien}}, publisher = {{Deutsche Gesellschaft für Akustik e.V. (DEGA)}}, title = {{{Application and modelling of ultrasonic transducers using 1-3 piezoelectric composites with structured electrodes}}}, 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}}, } @inproceedings{29938, abstract = {{Modular solid-state transformers (SSTs) are a promising technology in converting power from a 10kV three-phase medium voltage to a lower DC-voltage in the range of 100…400V to provide pure DC power to applications such as electrolyzers for hydrogen generation, data centers with a DC power distribution and DC micro grids. Modular SSTs which can be interpreted as modular multilevel converters with an isolated DC-DC output stage per module, are designed with redundant modules to increase reliability. Usually, each of the three arms operates independently, and therefore, only a fixed number of faulty modules can be compensated in each arm, even if all modules are operational in the remaining two arms. With the proposed zero-sequence voltage injection, up to 100% more faulty modules can be compensated in an arm by employing the same hardware. In addition, module power imbalances are nearly eliminated by utilizing a fundamental frequency zero-sequence voltage. A dominant 3rd harmonic zero-sequence voltage injection in combination with the 5th, 7th and several higher order harmonics with adaptive (small) amplitudes minimize the required arm voltages at steady-state. For nominal operation or symmetrical faults, the proposed technique is equivalent to the well known Min-Max voltage injection, which already reduces the peak arm voltage by 13.4% compared to a constant star point potential. A statistical analysis proves, that the expected number of tolerable faulty modules of the 1MW SST increases by 12% without the need for additional hardware.}}, author = {{Unruh, Roland and Lange, Jarren and Schafmeister, Frank and Böcker, Joachim}}, booktitle = {{23rd European Conference on Power Electronics and Applications (EPE'21 ECCE Europe)}}, isbn = {{978-9-0758-1537-5}}, keywords = {{Solid-State Transformer, Zero sequence voltage, Fault handling strategy, Power balance control technique, Three-phase system}}, location = {{Ghent, Belgium}}, publisher = {{IEEE}}, title = {{{Adaptive Zero-Sequence Voltage Injection for Modular Solid-State Transformer to Compensate for Asymmetrical Fault Conditions}}}, doi = {{https://doi.org/10.23919/EPE21ECCEEurope50061.2021.9570542}}, 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{35575, author = {{Schulze Darup, Moritz and Alexandru, Andreea B. and Quevedo, Daniel E. and Pappas, George J.}}, issn = {{1066-033X}}, journal = {{IEEE Control Systems}}, keywords = {{Electrical and Electronic Engineering, Modeling and Simulation, Control and Systems Engineering, Electrical and Electronic Engineering, Modeling and Simulation, Control and Systems Engineering}}, number = {{3}}, pages = {{58--78}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Encrypted Control for Networked Systems: An Illustrative Introduction and Current Challenges}}}, doi = {{10.1109/mcs.2021.3062956}}, volume = {{41}}, year = {{2021}}, } @article{35576, author = {{Schulze Darup, Moritz and Klädtke, Manuel and Mönnigmann, Martin}}, issn = {{2405-8963}}, journal = {{IFAC-PapersOnLine}}, keywords = {{Control and Systems Engineering}}, number = {{6}}, pages = {{290--295}}, publisher = {{Elsevier BV}}, title = {{{Exact solution to a special class of nonlinear MPC problems}}}, doi = {{10.1016/j.ifacol.2021.08.559}}, volume = {{54}}, year = {{2021}}, } @article{35578, author = {{Faulwasser, Timm and Lucia, Sergio and Schulze Darup, Moritz and Mönnigmann, Martin}}, issn = {{2405-8963}}, journal = {{IFAC-PapersOnLine}}, keywords = {{Control and Systems Engineering}}, number = {{6}}, pages = {{238--243}}, publisher = {{Elsevier BV}}, title = {{{Teaching MPC: Which Way to the Promised Land?}}}, doi = {{10.1016/j.ifacol.2021.08.551}}, volume = {{54}}, year = {{2021}}, } @inbook{35579, author = {{Schulze Darup, Moritz and Book, Gerrit}}, booktitle = {{Recent Advances in Model Predictive Control}}, isbn = {{9783030632809}}, issn = {{0170-8643}}, publisher = {{Springer International Publishing}}, title = {{{On Closed-Loop Dynamics of ADMM-Based MPC}}}, doi = {{10.1007/978-3-030-63281-6_5}}, year = {{2021}}, } @article{35571, author = {{Schulze Darup, Moritz and Book, Gerrit and Quevedo, Daniel E. and Nagahara, Masaaki}}, issn = {{0018-9286}}, journal = {{IEEE Transactions on Automatic Control}}, keywords = {{Electrical and Electronic Engineering, Computer Science Applications, Control and Systems Engineering}}, number = {{10}}, pages = {{5416--5423}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Fast Hands-Off Control Using ADMM Real-Time Iterations}}}, doi = {{10.1109/tac.2021.3121255}}, volume = {{67}}, year = {{2021}}, } @article{35572, author = {{Schluter, Nils and Darup, Moritz Schulze}}, issn = {{0018-9286}}, journal = {{IEEE Transactions on Automatic Control}}, keywords = {{Electrical and Electronic Engineering, Computer Science Applications, Control and Systems Engineering}}, number = {{10}}, pages = {{5610--5613}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{On the Stability of Linear Dynamic Controllers With Integer Coefficients}}}, doi = {{10.1109/tac.2021.3131126}}, volume = {{67}}, year = {{2021}}, } @article{35561, author = {{Darup, Moritz Schulze}}, issn = {{2405-8963}}, journal = {{IFAC-PapersOnLine}}, keywords = {{Control and Systems Engineering}}, number = {{2}}, pages = {{3508--3514}}, publisher = {{Elsevier BV}}, title = {{{Encrypted MPC based on ADMM real-time iterations}}}, doi = {{10.1016/j.ifacol.2020.12.1708}}, volume = {{53}}, year = {{2021}}, } @inproceedings{35555, author = {{Schluter, Nils and Schulze Darup, Moritz}}, booktitle = {{2020 59th IEEE Conference on Decision and Control (CDC)}}, publisher = {{IEEE}}, title = {{{Encrypted explicit MPC based on two-party computation and convex controller decomposition}}}, doi = {{10.1109/cdc42340.2020.9304078}}, year = {{2021}}, } @article{35589, author = {{Dragicevic, Tomislav and Parisio, Alessandra and Rodriguez, Jose and Jones, Colin and Quevedo, Daniel and Ferrarini, Luca and Preindl, Matthias and Shafiee, Qobad and Morstyn, Thomas}}, issn = {{0885-8969}}, journal = {{IEEE Transactions on Energy Conversion}}, keywords = {{Electrical and Electronic Engineering, Energy Engineering and Power Technology}}, number = {{2}}, pages = {{1311--1312}}, publisher = {{Institute of Electrical and Electronics Engineers (IEEE)}}, title = {{{Guest Editorial Model Predictive Control in Energy Conversion Systems}}}, doi = {{10.1109/tec.2021.3076279}}, volume = {{36}}, year = {{2021}}, } @unpublished{35588, abstract = {{We consider the joint design of control and scheduling under stochastic Denial-of-Service (DoS) attacks in the context of networked control systems. A sensor takes measurements of the system output and forwards its dynamic state estimates to a remote controller over a packet-dropping link. The controller determines the optimal control law for the process using the estimates it receives. An attacker aims at degrading the control performance by increasing the packet-dropout rate with a DoS attack towards the sensor-controller channel. We assume both the controller and the attacker are rational in a game-theoretic sense and establish a partially observable stochastic game to derive the optimal joint design of scheduling and control. Using dynamic programming we prove that the control and scheduling policies can be designed separately without sacrificing optimality, making the problem equivalent to a complete information game. We employ Nash Q-learning to solve the problem and prove that the solution is guaranteed to constitute an $\epsilon$-Nash equilibrium. Numerical examples are provided to illustrate the tradeoffs between control performance and communication cost.}}, author = {{Lu, Jingyi and Quevedo, Daniel E.}}, booktitle = {{arXiv:2103.05893}}, title = {{{A Jointly Optimal Design of Control and Scheduling in Networked Systems under Denial-of-Service Attacks}}}, year = {{2021}}, }