@inproceedings{16899, abstract = {{To compare efficiency and yield of many micro-inverters available on the world market in 2014-2020, an in- and outdoor test laboratory at the University of Paderborn has been set up. The inverters have been fed by identical and calibrated crystalline silicon PV modules of 215 Wp. To monitor accurately DC input, AC power output and energy yield, each of the micro-inverters has been equipped with a calibrated electricity meter. For micro-inverters requiring control units for grid-feeding that has been acquired also. The comparison covers efficiency-load characteristics as well as electrical energy yields. Purchase costs vary considerably between the models in comparison, sometimes inverter costs are higher than module costs, particularly if an additional grid-connection or interface device is needed for operation. The weighted conversion efficiency according to EU and CEC standards has been measured and calculated. While some inverters have been optimized for high irradiance levels, they ranked better at the CEC efficiency, others performed very well also for low irradiance levels, thus ranking higher at in the EU-efficiency tables. These results are deviating from the actual energy yield measurements, which show a slightly different ranking. At one inverter, an accurate, but very slow MPPT algorithm that barely could follow quickly changing irradiance levels could be the reason for this effect. Another inverter switched off after operation at high power output for a while. Apparently, some inverters are been optimized to show excellent EU and CEC efficiency ratings. Two of the inverters featuring two inputs did not show an exceptional performance at the EU- and CEC-ratings, but they achieved top ranks at the AC energy yield for the first years. For the customer, the AC yield is a major performance indicator of any microinverter and should be included in the datasheet.}}, author = {{Krauter, Stefan and Bendfeld, Jörg}}, booktitle = {{Proceedings of the 47th IEEE Photovoltaic Specialists Conference (PVSC 47) JUNE 15 - AUGUST 21, 2020 VIRTUAL MEETING}}, issn = {{ 0160-8371}}, keywords = {{yield, AC, micro-inverter, MPPT, CEC rating, EU efficiency, Photovoltaic, Solar}}, location = {{VIRTUAL MEETING}}, pages = {{1429--1432}}, publisher = {{IEEE}}, title = {{{Comparison of Microinverters: Update on Rankings of Conversion Efficiencies and Energy Yields}}}, doi = {{10.1109/PVSC45281.2020.9300953}}, year = {{2020}}, } @inproceedings{16855, author = {{Krauter, Stefan and Zhang, L.}}, booktitle = {{Tagungsband des 35. Symposiums für Photovoltaische Solarenergie, Kloster Banz, Bad Staffelstein (Deutschland)}}, location = {{Bad Staffelstein}}, title = {{{Eignung der Netzfrequenz als Instrument der Entscheidungsfindung zur Auslösung von Lastverschiebungen bei niedrigen spezifischen CO2-Emissionen und EEX-Handelspreisen}}}, year = {{2020}}, } @inproceedings{16858, author = {{Krauter, Stefan and Zhang, L.}}, booktitle = {{Proceedings of the 14th International Renewable Energy Storage Conference, Düsseldorf (Deutschland), 10.–12. März 2020 (verschoben: 16.–18. März 2021)}}, location = {{Düsseldorf (Deutschland)}}, title = {{{Probability of Correct Decision–Making at Triggering of Load-Shifting Intended for low CO2-intensity and low EEX trading-prices via simple Grid Frequency Monitoring}}}, year = {{2020}}, } @inproceedings{20504, abstract = {{In recent years time domain speech separation has excelled over frequency domain separation in single channel scenarios and noise-free environments. In this paper we dissect the gains of the time-domain audio separation network (TasNet) approach by gradually replacing components of an utterance-level permutation invariant training (u-PIT) based separation system in the frequency domain until the TasNet system is reached, thus blending components of frequency domain approaches with those of time domain approaches. Some of the intermediate variants achieve comparable signal-to-distortion ratio (SDR) gains to TasNet, but retain the advantage of frequency domain processing: compatibility with classic signal processing tools such as frequency-domain beamforming and the human interpretability of the masks. Furthermore, we show that the scale invariant signal-to-distortion ratio (si-SDR) criterion used as loss function in TasNet is related to a logarithmic mean square error criterion and that it is this criterion which contributes most reliable to the performance advantage of TasNet. Finally, we critically assess which gains in a noise-free single channel environment generalize to more realistic reverberant conditions.}}, author = {{Heitkaemper, Jens and Jakobeit, Darius and Boeddeker, Christoph and Drude, Lukas and Haeb-Umbach, Reinhold}}, booktitle = {{ICASSP 2020 Virtual Barcelona Spain}}, keywords = {{voice activity detection, speech activity detection, neural network, statistical speech processing}}, title = {{{Demystifying TasNet: A Dissecting Approach}}}, year = {{2020}}, } @unpublished{28263, abstract = {{Following the success of the 1st, 2nd, 3rd, 4th and 5th CHiME challenges we organize the 6th CHiME Speech Separation and Recognition Challenge (CHiME-6). The new challenge revisits the previous CHiME-5 challenge and further considers the problem of distant multi-microphone conversational speech diarization and recognition in everyday home environments. Speech material is the same as the previous CHiME-5 recordings except for accurate array synchronization. The material was elicited using a dinner party scenario with efforts taken to capture data that is representative of natural conversational speech. This paper provides a baseline description of the CHiME-6 challenge for both segmented multispeaker speech recognition (Track 1) and unsegmented multispeaker speech recognition (Track 2). Of note, Track 2 is the first challenge activity in the community to tackle an unsegmented multispeaker speech recognition scenario with a complete set of reproducible open source baselines providing speech enhancement, speaker diarization, and speech recognition modules.}}, author = {{Watanabe, Shinji and Mandel, Michael and Barker, Jon and Vincent, Emmanuel and Arora, Ashish and Chang, Xuankai and Khudanpur, Sanjeev and Manohar, Vimal and Povey, Daniel and Raj, Desh and Snyder, David and Subramanian, Aswin Shanmugam and Trmal, Jan and Yair, Bar Ben and Boeddeker, Christoph and Ni, Zhaoheng and Fujita, Yusuke and Horiguchi, Shota and Kanda, Naoyuki and Yoshioka, Takuya and Ryant, Neville}}, booktitle = {{arXiv:2004.09249}}, title = {{{CHiME-6 Challenge:Tackling Multispeaker Speech Recognition for Unsegmented Recordings}}}, year = {{2020}}, } @inproceedings{29200, author = {{Sadeghi-Kohan, Somayeh and Hellebrand, Sybille}}, booktitle = {{38th IEEE VLSI Test Symposium (VTS)}}, publisher = {{IEEE}}, title = {{{Dynamic Multi-Frequency Test Method for Hidden Interconnect Defects}}}, doi = {{10.1109/vts48691.2020.9107591}}, year = {{2020}}, } @inproceedings{19421, author = {{Holst, Stefan and Kampmann, Matthias and Sprenger, Alexander and Reimer, Jan Dennis and Hellebrand, Sybille and Wunderlich, Hans-Joachim and Weng, Xiaoqing}}, booktitle = {{IEEE International Test Conference (ITC'20), November 2020}}, title = {{{Logic Fault Diagnosis of Hidden Delay Defects}}}, year = {{2020}}, } @inproceedings{21719, abstract = {{We fabricate silicon tapers to increase the mode overlap of superconducting detectors on Ti:LiNbO3 waveguides. Mode images show a reduction in mode size from 6 µm to 2 µm FWHM, agreeing with beam propagation simulations.}}, author = {{Protte, Maximilian and Ebers, Lena and Hammer, Manfred and Höpker, Jan Philipp and Albert, Maximilian and Quiring, Viktor and Meier, Cedrik and Förstner, Jens and Silberhorn, Christine and Bartley, Tim}}, booktitle = {{OSA Quantum 2.0 Conference}}, isbn = {{9781943580811}}, keywords = {{tet_topic_waveguide}}, title = {{{Towards Semiconductor-Superconductor-Crystal Hybrid Integration for Quantum Photonics}}}, doi = {{10.1364/quantum.2020.qth7a.8}}, year = {{2020}}, } @inproceedings{35559, author = {{Schulze Darup, Moritz and Jager, Tibor}}, booktitle = {{2019 IEEE 58th Conference on Decision and Control (CDC)}}, publisher = {{IEEE}}, title = {{{Encrypted Cloud-based Control using Secret Sharing with One-time Pads}}}, doi = {{10.1109/cdc40024.2019.9029342}}, year = {{2020}}, } @inproceedings{35558, author = {{Schulze Darup, Moritz }}, booktitle = {{2020 European Control Conference (ECC)}}, publisher = {{IEEE}}, title = {{{Exact representation of piecewise affine functions via neural networks}}}, doi = {{10.23919/ecc51009.2020.9143957}}, year = {{2020}}, } @inproceedings{35567, author = {{Alexandru, Andreea B. and Schulze Darup, Moritz and Pappas, George J.}}, booktitle = {{2019 IEEE 58th Conference on Decision and Control (CDC)}}, publisher = {{IEEE}}, title = {{{Encrypted Cooperative Control Revisited}}}, doi = {{10.1109/cdc40024.2019.9030124}}, year = {{2020}}, } @article{35580, author = {{Schulze Darup, Moritz}}, issn = {{1049-8923}}, journal = {{International Journal of Robust and Nonlinear Control}}, keywords = {{Electrical and Electronic Engineering, Industrial and Manufacturing Engineering, Mechanical Engineering, Aerospace Engineering, Biomedical Engineering, General Chemical Engineering, Control and Systems Engineering}}, number = {{11}}, pages = {{4168--4187}}, publisher = {{Wiley}}, title = {{{Encrypted polynomial control based on tailored two‐party computation}}}, doi = {{10.1002/rnc.5003}}, volume = {{30}}, year = {{2020}}, } @article{35585, author = {{Lu, Jingyi and Leong, Alex S. and Quevedo, Daniel E.}}, issn = {{1049-8923}}, journal = {{International Journal of Robust and Nonlinear Control}}, keywords = {{Electrical and Electronic Engineering, Industrial and Manufacturing Engineering, Mechanical Engineering, Aerospace Engineering, Biomedical Engineering, General Chemical Engineering, Control and Systems Engineering}}, number = {{11}}, pages = {{4205--4224}}, publisher = {{Wiley}}, title = {{{Optimal event‐triggered transmission scheduling for privacy‐preserving wireless state estimation}}}, doi = {{10.1002/rnc.4910}}, volume = {{30}}, year = {{2020}}, } @inproceedings{24020, abstract = {{Novel analog-to-digital converter (ADC) architectures are motivated by the demand for rising sampling rates and effective number of bits (ENOB). The main limitation on ENOB in purely electrical ADCs lies in the relatively high jitter of oscillators, in the order of a few tens of fs for state-of-the-art components. When compared to the extremely low jitter obtained with best-in-class Ti:sapphire mode-locked lasers (MLL), in the attosecond range, it is apparent that a mixed electrical-optical architecture could significantly improve the converters' ENOB. We model and analyze the ENOB limitations arising from optical sources in optically enabled, spectrally sliced ADCs, after discussing the system architecture and implementation details. The phase noise of the optical carrier, serving for electro-optic signal transduction, is shown not to propagate to the reconstructed digitized signal and therefore not to represent a fundamental limit. The optical phase noise of the MLL used to generate reference tones for individual slices also does not fundamentally impact the converted signal, so long as it remains correlated among all the comb lines. On the other hand, the timing jitter of the MLL, as also reflected in its RF linewidth, is fundamentally limiting the ADC performance, since it is directly mapped as jitter to the converted signal. The hybrid nature of a photonically enabled, spectrally sliced ADC implies the utilization of a number of reduced bandwidth electrical ADCs to convert parallel slices, resulting in the propagation of jitter from the electrical oscillator supplying their clock. Due to the reduced sampling rate of the electrical ADCs, as compared to the overall system, the overall noise performance of the presented architecture is substantially improved with respect to a fully electrical ADC.}}, author = {{Zazzi, Andrea and Müller, Juliana and Gudyriev, Sergiy and Marin-Palomo, Pablo and Fang, Dengyang and Scheytt, Christoph and Koos, Christian and Witzens, Jeremy}}, booktitle = {{21. ITG-Fachtagung Photonische Netze}}, publisher = {{VDE-Verlag}}, title = {{{Mode-locked laser timing jitter limitation in optically enabled frequency-sliced ADCs}}}, year = {{2020}}, } @article{24025, abstract = {{The effect of phase noise introduced by optical sources in spectrally-sliced optically enabled DACs and ADCs is modeled and analyzed in detail. In both data converter architectures, a mode-locked laser is assumed to provide an optical comb whose lines are used to either synthesize or analyze individual spectral slices. While the optical phase noise of the central MLL line as well as of other optical carriers used in the analyzed system architectures have a minor impact on the system performance, the RF phase noise of the MLL fundamentally limits it. In particular, the corresponding jitter of the MLL pulse train is transferred almost one-to-one to the system-level timing jitter of the data converters. While MLL phase noise can in principle be tracked and removed by electronic signal processing, this results in electric oscillator phase noise replacing the MLL jitter and is not conducive in systems leveraging the ultra-low jitter of low-noise mode-locked lasers. Precise analytical models are derived and validated by detailed numerical simulations.}}, author = {{Zazzi, Andrea and Müller, Juliana and Gudyriev, Sergiy and Marin-Palomo, Pablo and Fang, Dengyang and Scheytt, Christoph and Koos, Christian and Witzens, Jeremy}}, journal = {{Opt. Express}}, title = {{{Fundamental limitations of spectrally-sliced optically enabled data converters arising from MLL timing jitter}}}, doi = {{10.1364/OE.382832}}, volume = {{28}}, year = {{2020}}, } @inproceedings{24028, abstract = {{A 28 Gbps NRZ bang-bang clock and data recovery (CDR) chip for 100G PSM4 is presented. It exhibits an adaptable loop filter transfer function with independently tunable proportional and integral parameters. This allows to optimize the jitter transfer, jitter tolerance, and locking range of the CDR according to system requirements. The CDR represents a key component for a single-chip 8-channel electronic-photonic PSM4 transceiver. A CDR chip was manufactured in a 0.25 μm monolithic photonic BiCMOS technology. The core chip area is 0.51 mm 2 and it dissipates 330 mW from 2.5 V and 3.3 V power supplies.}}, author = {{Iftekhar, Mohammed and Gudyriev, Sergiy and Scheytt, Christoph}}, booktitle = {{2020 IEEE 20th Topical Meeting on Silicon Monolithic Integrated Circuits in RF Systems (SiRF)}}, publisher = {{IEEE}}, title = {{{28 Gbps Bang-Bang CDR for 100G PSM4 with Independently Tunable Proportional and Integral Parameters of the Loop Filter in 0.25 µm Photonic BiCMOS Technology}}}, doi = {{10.1109/SIRF46766.2020.9040190}}, year = {{2020}}, } @inproceedings{24024, abstract = {{Recently it has been demonstrated that an optoelectronic phase-locked loop (OEPLL) using a mode-locked laser as a reference oscillator achieves significantly lower phase noise than conventional electronic frequency synthesizers. In this paper a concept for an OEPLL-based frequency synthesizer is presented and it is investigated how it can be used as a local oscillator (LO) for THz transceivers in order to improve the signal quality in THz wireless communications. The concept of the OEPLL is presented and it's measured phase noise is compared to the phase noise of a laboratory-grade electronic frequency synthesizer. The measured phase noise spectra of both synthesizers at 10 GHz are then used to model LO phase noise at 320 GHz. Based on models of generic zero-IF transmit and receive frontends, THz signals with different modulation formats and Baud rates are simulated at system level using the modeled LO phase noise for the two LO approaches. Finally, the results are compared.}}, author = {{Scheytt, Christoph and Wrana, Dominik and Bahmanian, Meysam and Kallfass, Ingmar}}, booktitle = {{2020 Third International Workshop on Mobile Terahertz Systems (IWMTS)}}, location = {{Essen, Germany }}, title = {{{Ultra-Low Phase Noise Frequency Synthesis for THz Communications Using Optoelectronic PLLs}}}, doi = {{10.1109/IWMTS49292.2020.9166347}}, year = {{2020}}, } @inproceedings{20505, abstract = {{Speech activity detection (SAD), which often rests on the fact that the noise is "more'' stationary than speech, is particularly challenging in non-stationary environments, because the time variance of the acoustic scene makes it difficult to discriminate speech from noise. We propose two approaches to SAD, where one is based on statistical signal processing, while the other utilizes neural networks. The former employs sophisticated signal processing to track the noise and speech energies and is meant to support the case for a resource efficient, unsupervised signal processing approach. The latter introduces a recurrent network layer that operates on short segments of the input speech to do temporal smoothing in the presence of non-stationary noise. The systems are tested on the Fearless Steps challenge database, which consists of the transmission data from the Apollo-11 space mission. The statistical SAD achieves comparable detection performance to earlier proposed neural network based SADs, while the neural network based approach leads to a decision cost function of 1.07% on the evaluation set of the 2020 Fearless Steps Challenge, which sets a new state of the art.}}, author = {{Heitkaemper, Jens and Schmalenstroeer, Joerg and Haeb-Umbach, Reinhold}}, booktitle = {{INTERSPEECH 2020 Virtual Shanghai China}}, keywords = {{voice activity detection, speech activity detection, neural network, statistical speech processing}}, title = {{{Statistical and Neural Network Based Speech Activity Detection in Non-Stationary Acoustic Environments}}}, year = {{2020}}, } @inproceedings{20762, abstract = {{The rising interest in single-channel multi-speaker speech separation sparked development of End-to-End (E2E) approaches to multispeaker speech recognition. However, up until now, state-of-theart neural network–based time domain source separation has not yet been combined with E2E speech recognition. We here demonstrate how to combine a separation module based on a Convolutional Time domain Audio Separation Network (Conv-TasNet) with an E2E speech recognizer and how to train such a model jointly by distributing it over multiple GPUs or by approximating truncated back-propagation for the convolutional front-end. To put this work into perspective and illustrate the complexity of the design space, we provide a compact overview of single-channel multi-speaker recognition systems. Our experiments show a word error rate of 11.0% on WSJ0-2mix and indicate that our joint time domain model can yield substantial improvements over cascade DNN-HMM and monolithic E2E frequency domain systems proposed so far.}}, author = {{von Neumann, Thilo and Kinoshita, Keisuke and Drude, Lukas and Boeddeker, Christoph and Delcroix, Marc and Nakatani, Tomohiro and Haeb-Umbach, Reinhold}}, booktitle = {{ICASSP 2020 - 2020 IEEE International Conference on Acoustics, Speech and Signal Processing (ICASSP)}}, pages = {{7004--7008}}, title = {{{End-to-End Training of Time Domain Audio Separation and Recognition}}}, doi = {{10.1109/ICASSP40776.2020.9053461}}, year = {{2020}}, } @inproceedings{20764, abstract = {{Most approaches to multi-talker overlapped speech separation and recognition assume that the number of simultaneously active speakers is given, but in realistic situations, it is typically unknown. To cope with this, we extend an iterative speech extraction system with mechanisms to count the number of sources and combine it with a single-talker speech recognizer to form the first end-to-end multi-talker automatic speech recognition system for an unknown number of active speakers. Our experiments show very promising performance in counting accuracy, source separation and speech recognition on simulated clean mixtures from WSJ0-2mix and WSJ0-3mix. Among others, we set a new state-of-the-art word error rate on the WSJ0-2mix database. Furthermore, our system generalizes well to a larger number of speakers than it ever saw during training, as shown in experiments with the WSJ0-4mix database. }}, author = {{von Neumann, Thilo and Boeddeker, Christoph and Drude, Lukas and Kinoshita, Keisuke and Delcroix, Marc and Nakatani, Tomohiro and Haeb-Umbach, Reinhold}}, booktitle = {{Proc. Interspeech 2020}}, pages = {{3097--3101}}, title = {{{Multi-Talker ASR for an Unknown Number of Sources: Joint Training of Source Counting, Separation and ASR}}}, doi = {{10.21437/Interspeech.2020-2519}}, year = {{2020}}, }