检索结果-内蒙古大学图书馆

arXiv 2021年

作者： Reinke, Annika Tizabi, Minu D. Sudre, Carole H. Eisenmann, Matthias Rädsch, Tim Baumgartner, Michael Acion, Laura Antonelli, Michela Arbel, Tal Bakas, Spyridon Bankhead, Peter Benis, Arriel Blaschko, Matthew Buettner, Florian Cardoso, M. Jorge Chen, Jianxu Cheplygina, Veronika Christodoulou, Evangelia Cimini, Beth A. Collins, Gary S. Engelhardt, Sandy Farahani, Keyvan Ferrer, Luciana Galdran, Adrian van Ginneken, Bram Glocker, Ben Godau, Patrick Haase, Robert Hamprecht, Fred Hashimoto, Daniel A. Heckmann-Nötzel, Doreen Hirsch, Peter Hoffman, Michael M. Huisman, Merel Isensee, Fabian Jannin, Pierre Kahn, Charles E. Kainmueller, Dagmar Kainz, Bernhard Karargyris, Alexandros Karthikesalingam, Alan Kavur, A. Emre Kenngott, Hannes Kleesiek, Jens Kleppe, Andreas Koehler, Sven Kofler, Florian Kopp-Schneider, Annette Kooi, Thijs Kozubek, Michal Kreshuk, Anna Kurc, Tahsin Landman, Bennett A. Litjens, Geert Madani, Amin Maier-Hein, Klaus Martel, Anne L. Mattson, Peter Meijering, Erik Menze, Bjoern Moher, David Moons, Karel G.M. Müller, Henning Nichyporuk, Brennan Nickel, Felix Noyan, M. Alican Petersen, Jens Polat, Gorkem Rafelski, Susanne M. Rajpoot, Nasir Reyes, Mauricio Rieke, Nicola Riegler, Michael A. Rivaz, Hassan Saez-Rodriguez, Julio Sánchez, Clara I. Schroeter, Julien Saha, Anindo Selver, M. Alper Sharan, Lalith Shetty, Shravya Smeden, Maarten V.A.N. Stieltjes, Bram Summers, Ronald M. Taha, Abdel A. Tiulpin, Aleksei Tsaftaris, Sotirios A. Calster, Ben V.A.N. Varoquaux, Gaël Wiesenfarth, Manuel Yaniv, Ziv R. Jäger, Paul Maier-Hein, Lena Division of Intelligent Medical Systems and HI Helmholtz Imaging Heidelberg Germany Faculty of Mathematics and Computer Science Heidelberg University Heidelberg Germany Division of Intelligent Medical Systems Heidelberg Germany NCT Heidelberg DKFZ University Medical Center Heidelberg Germany MRC Unit for Lifelong Health and Ageing UCL Centre for Medical Image Computing Department of Computer Science University College London London United Kingdom School of Biomedical Engineering and Imaging Science King’s College London London United Kingdom Division of Medical Image Computing Heidelberg Germany Instituto de Cálculo CONICET – Universidad de Buenos Aires Buenos Aires Argentina Centre for Medical Image Computing University College London London United Kingdom McGill University Montréal Canada Division of Computational Pathology Dept of Pathology & Laboratory Medicine Indiana University School of Medicine IU Health Information and Translational Sciences Building Indianapolis United States University of Pennsylvania Richards Medical Research Laboratories FL7 PhiladelphiaPA United States Institute of Genetics and Cancer University of Edinburgh Edinburgh United Kingdom Department of Digital Medical Technologies Holon Institute of Technology Holon Israel European Federation for Medical Informatics Le Mont-sur-Lausanne Switzerland Center for Processing Speech and Images Department of Electrical Engineering KU Leuven Kasteelpark Arenberg 10 - box 2441 Leuven3001 Belgium Frankfurt/Mainz DKFZ UCT Frankfurt-Marburg Germany Heidelberg Germany Goethe University Frankfurt Department of Medicine Germany Goethe University Frankfurt Department of Informatics Germany Frankfurt Cancer Insititute Germany Leibniz-Institut für Analytische Wissenschaften – ISAS – e.V. Dortmund Germany Department of Computer Science IT University of Copenhagen Copenhagen Denmark Imaging Platform Broad Institute of MIT and Harvard CambridgeMA United States Centre for St

While the importance of automatic image analysis is continuously increasing, recent meta-research revealed major flaws with respect to algorithm validation. Performance metrics are particularly key for meaningful, objective, and transparent performance assessment and validation of the used automatic algorithms, but relatively little attention has been given to the practical pitfalls when using specific metrics for a given image analysis task. These are typically related to (1) the disregard of inherent metric properties, such as the behaviour in the presence of class imbalance or small target structures, (2) the disregard of inherent data set properties, such as the non-independence of the test cases, and (3) the disregard of the actual biomedical domain interest that the metrics should reflect. This living dynamically document has the purpose to illustrate important limitations of performance metrics commonly applied in the field of image analysis. In this context, it focuses on biomedical image analysis problems that can be phrased as image-level classification, semantic segmentation, instance segmentation, or object detection task. The current version is based on a Delphi process on metrics conducted by an international consortium of image analysis experts from more than 60 institutions worldwide. © 2021, CC BY.

关键词： Medical imaging

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First dust measurements with the solar orbiter radio and plasma wave instrument

arXiv

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arXiv 2021年

作者： Zaslavsky, A. Mann, I. Soucek, J. Czechowski, A. Pisa, D. Vaverka, J. Meyer-Vernet, N. Maksimovic, M. Lorfèvre, E. Issautier, K. Racković Babić, K. Bale, S.D. Morooka, M. Vecchio, A. Chust, T. Khotyaintsev, Y. Krasnoselskikh, V. Kretzschmar, M. Plettemeier, D. Steller, M. Štverák, S. Trávníček, P. Vaivads, A. Lesia Observatoire de Paris Université Psl Cnrs Sorbonne Université Université de Paris France Arctic University of Norway Tromsø Norway Institute of Atmospheric Physics of the Czech Academy of Sciences Prague Czech Republic Space Research Center Polish Academy of Sciences Warsaw Poland Faculty of Mathematics and Physics Charles University Prague Czech Republic Cnes 18 Avenue Edouard Belin Toulouse31400 France Department of Astronomy Faculty of Mathematics University of Belgrade Serbia Space Sciences Laboratory University of California BerkeleyCA United States Physics Department University of California BerkeleyCA United States Swedish Institute of Space Physics Uppsala Sweden Radboud Radio Lab Department of Astrophysics Radboud University Nijmegen Netherlands Lpp Cnrs Ecole Polytechnique Sorbonne Université Observatoire de Paris Université Paris-Saclay Palaiseau Paris France LPC2E Cnrs 3A avenue de la Recherche Scientifique Orléans France Université D'Orléans Orléans France Technische Universität Dresden Würzburger Str. 35 DresdenD-01187 Germany Space Research Institute Austrian Academy of Sciences Graz Austria Astronomical Institute of the Czech Academy of Sciences Prague Czech Republic Department of Space and Plasma Physics School of Electrical Engineering and Computer Science Royal Institute of Technology Stockholm Sweden

Context. Impacts of dust grains on spacecraft are known to produce typical impulsive signals in the voltage waveform recorded at the terminals of electric antennas. Such signals are, as could be expected, routinely detected by the Time Domain Sampler (TDS) system of the Radio and plasma Waves (RPW) instrument aboard Solar Orbiter. Aims. We investigate the capabilities of RPW in terms of interplanetary dust studies and present the first analysis of dust impacts recorded by this instrument. Our purpose is to characterize the dust population observed in terms of size, flux and velocity. Methods. We briefly discuss previously developed models of voltage pulses generation after a dust impact onto a spacecraft and present the relevant technical parameters for Solar Orbiter RPW as a dust detector. Then we present the statistical analysis of the dust impacts recorded by RPW/TDS from April 20th, 2020 to February 27th, 2021 between 0.5 AU and 1 AU. Results. The study of the dust impact rate along Solar Orbiter's orbit shows that the dust population studied presents a radial velocity component directed outward from the Sun, the order of magnitude of which can be roughly estimated as vr,dust≅ 50 km.s-1. This is consistent with the flux of impactors being dominated by β-meteoroids. We estimate the cumulative flux of these grains at 1 AU to be roughly Fβ≅ 8×10-5m-2s-1, for particles of radius r 100 nm. The power law index δ of the cumulative mass flux of the impactors is evaluated by two differents methods (direct observations of voltage pulses and indirect effect on the impact rate dependency on the impact speed). Both methods give a result δ ≅ 0.3 - 0.4. Conclusions. Solar Orbiter RPW proves to be a suitable instrument for interplanetary dust studies, and the dust detection algorithm implemented in the TDS subsystem an efficient tool for fluxes estimation. These first results are promising for the continuation of the mission, in particular for the in-situ study of the dust clou

关键词： Orbits

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Efficient T2 mapping with Blip-up/down EPI and gSlider-SMS (T2-BUDA-gSlider)

arXiv

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arXiv 2019年

作者： Cao, Xiaozhi Liao, Congyu Zhang, Zijing Iyer, Siddharth Srinivasan Chen, Zhifeng Lo, Wei-Ching Liu, Huafeng Wang, Kang He, Hongjian Setsompop, Kawin Zhong, Jianhui Bilgic, Berkin Center for Brain Imaging Science and Technology Department of Biomedical Engineering Zhejiang University Zhejiang Hangzhou China Athinoula A. Martinos Center for Biomedical Imaging Massachusetts General Hospital CharlestownMA United States Department of Radiology Harvard Medical School CharlestownMA United States State Key Laboratory of Modern Optical Instrumentation College of Optical Science and Engineering Zhejiang University Zhejiang Hangzhou China Department of Electrical Engineering and Computer Science Massachusetts Institute of Technology CambridgeMA United States School of Biomedical Engineering Guangdong Provincial Key Laboratory of Medical Image Processing Southern Medical University Guangzhou China Siemens Medical Solutions BostonMA United States Department of Neurology The First Affiliated Hospital School of Medicine Zhejiang University Hangzhou China Harvard-MIT Department of Health Sciences and Technology CambridgeMA United States Department of Imaging Sciences University of Rochester NY United States

Purpose: To rapidly obtain high isotropic-resolution T2 maps with whole-brain coverage and high geometric fidelity. Methods: A T2 blip-up/down echo planar imaging (EPI) acquisition with generalized Slice-dithered enhanced resolution (T2-BUDA-gSlider) is proposed. A radiofrequency (RF)-encoded multi-slab spin-echo EPI acquisition with multiple echo times (TEs) was developed to obtain high SNR efficiency with reduced repetition time (TR). This was combined with an interleaved 2-shot EPI acquisition using blip-up/down phase encoding. An estimated field map was incorporated into the joint multi-shot EPI reconstruction with a structured low rank constraint to achieve distortion-free and robust reconstruction for each slab without navigation. A Bloch simulated subspace model was integrated into gSlider reconstruction and utilized for T2 quantification. Results: In vivo results demonstrated that the T2 values estimated by the proposed method were consistent with gold standard spin-echo acquisition. Compared to the reference 3D fast spin echo (FSE) images, distortion caused by off-resonance and eddy current effects were effectively mitigated. Conclusion: BUDA-gSlider SE-EPI acquisition and gSlider-subspace joint reconstruction enabled distortion-free whole-brain T2 mapping in 2 min at ~1 mm3 isotropic resolution, which could bring significant benefits to related clinical and neuroscience applications. Copyright © 2019, The Authors. All rights reserved.

关键词： Spin polarization

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Kinetic electrostatic waves and their association with current structures in the solar wind

arXiv

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arXiv 2021年

作者： Graham, Daniel B. Khotyaintsev, Yu.V. Vaivads, A. Edberg, N.J.T. Eriksson, A.I. Johansson, E. Sorriso-Valvo, L. Maksimovic, M. Souček, J. Píša, D. Bale, S.D. Chust, T. Kretzschmar, M. Krasnoselskikh, V. Lorfèvre, E. Plettemeier, D. Steller, M. Štverák, Š. Trávníček, P. Vecchio, A. Horbury, T.S. O'Brien, H. Evans, V. Angelini, V. Uppsala75121 Sweden Division of Space and Plasma Physics School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm11428 Sweden LESIA Observatoire de Paris Université PSL CNRS Sorbonne Université Univ. Paris Diderot Sorbonne Paris Cité 5 place Jules Janssen Meudon92195 France Institute of Atmospheric Physics The Czech Academy of Sciences Prague Czech Republic Space Sciences Laboratory University of California BerkeleyCA United States Physics Department University of California BerkeleyCA United States LPP CNRS Ecole Polytechnique Sorbonne Université Observatoire de Paris Université Paris-Saclay Palaiseau Paris France LPC2E CNRS 3A avenue de la Recherche Scientifique Orléans France Université d'Orléans Orléans France CNES 18 Avenue Edouard Belin Toulouse31400 France Technische Universität Dresden Helmholtz Str. 10 DresdenD-01187 Germany Space Research Institute Austrian Academy of Sciences Graz Austria Astronomical Institute The Czech Academy of Sciences Prague Czech Republic Radboud Radio Lab Department of Astrophysics Radboud University Nijmegen Netherlands Imperial College London South Kensington Campus LondonSW7 2AZ United Kingdom

Context. A variety of kinetic electrostatic and electromagnetic waves develop in the solar wind. The relationship between these waves and larger-scale structures, such as current sheets and ongoing turbulence remain a topic of investigation. Similarly, the instabilities producing ion-acoustic waves in the solar wind remains an open question. Aims. The goals of this paper are to investigate kinetic electrostatic Langmuir and ion-acoustic waves in the solar wind at 0.5 AU and determine whether current sheets and associated streaming instabilities can produce the observed waves. The relationship between these waves and currents observed in the solar wind is investigated statistically. Methods. Solar Orbiter's Radio and plasma Waves (RPW) instrument suite provides high-resolution snapshots of the fluctuating electric field. The Low Frequency Receiver (LFR) resolves the waveforms of ion-acoustic waves and the Time Domain Sampler (TDS) resolves the waveforms of both ion-acoustic and Langmuir waves. Using these waveform data we determine when these waves are observed in relation to current structures in the solar wind, estimated from the background magnetic field. Results. Langmuir and ion-acoustic waves are frequently observed in the solar wind. Ion-acoustic waves are observed about 1% of the time at 0.5 AU. The waves are more likely to be observed in regions of enhanced currents. However, the waves typically do not occur at current structures themselves. The observed currents in the solar wind are too small to drive instability by the relative drift between single ion and electron populations. When multi-component ion and/or electron distributions are present the observed currents may be sufficient for instability. Ion beams are the most plausible source of ion-acoustic waves in the solar wind. The spacecraft potential is confirmed to be a reliable probe of the background electron density by comparing the peak frequencies of Langmuir waves with the plasma frequency calcu

关键词： Turbulence

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Solar Orbiter/RPW antenna calibration in the radio domain and its application to type III burst observations

arXiv

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arXiv 2021年

作者： Vecchio, A. Maksimovic, M. Krupar, V. Bonnin, X. Zaslavsky, A. Astier, P.L. Dekkali, M. Cecconi, B. Bale, S.D. Chust, T. Guilhem, E. Khotyaintsev, Yu.V. Krasnoselskikh, V. Kretzschmar, M. Lorfèvre, E. Plettemeier, D. Souček, J. Steller, M. Štverák, S. Trávníček, P. Vaivads, A. Radboud Radio Lab Department of Astrophysics Radboud University Nijmegen Netherlands Lesia Observatoire de Paris Université Psl Cnrs Sorbonne Université Université de Paris France Goddard Planetary Heliophysics Institute University of Maryland Baltimore County BaltimoreMD United States Heliophysics Science Division Nasa Goddard Space Flight Center GreenbeltMD United States Space Sciences Laboratory University of California BerkeleyCA United States Physics Department University of California BerkeleyCA United States Lpp Cnrs Ecole Polytechnique Sorbonne Université Observatoire de Paris Université Paris-Saclay Palaiseau Paris France Cnes 18 Avenue Edouard Belin Toulouse31400 France Uppsala Sweden LPC2E Cnrs 3A avenue de la Recherche Scientifique Orléans France Technische Universität Dresden Würzburger Str. 35 DresdenD-01187 Germany Institute of Atmospheric Physics of the Czech Academy of Sciences Prague Czech Republic Space Research Institute Austrian Academy of Sciences Graz Austria Astronomical Institute of the Czech Academy of Sciences Ondvrejov Czech Republic Space and Plasma Physics School of Electrical Engineering and Computer Science Kth Royal Institute of Technology Stockholm Sweden

Context. In order to allow for a comparison with the measurements from other antenna systems, the voltage power spectral density measured by the Radio and plasma waves receiver (RPW) on board Solar Orbiter needs to be converted into physical quantities that depend on the intrinsic properties of the radiation itself (e.g., the brightness of the source). Aims. The main goal of this study is to perform a calibration of the RPW dipole antenna system that allows for the conversion of the voltage power spectral density measured at the receiver's input into the incoming flux density. Methods. We used space observations from the Thermal Noise Receiver (TNR) and the High Frequency Receiver (HFR) to perform the calibration of the RPW dipole antenna system. Observations of type III bursts by theWind spacecraft are used to obtain a reference radio flux density for cross-calibrating the RPW dipole antennas. The analysis of a large sample of HFR observations (over about ten months), carried out jointly with an analysis of TNR-HFR data and prior to the antennas' deployment, allowed us to estimate the reference system noise of the TNR-HFR receivers. Results. We obtained the effective length, leff, of the RPW dipoles and the reference system noise of TNR-HFR in space, where the antennas and pre-amplifiers are embedded in the solar wind plasma. The obtained leffvalues are in agreement with the simulation and measurements performed on the ground. By investigating the radio flux intensities of 35 type III bursts simultaneously observed by Solar Orbiter and Wind, we found that while the scaling of the decay time as a function of the frequency is the same for the Waves and RPW instruments, their median values are higher for the former. This provides the first observational evidence that Type III radio waves still undergo density scattering, even when they propagate from the source, in a medium with a plasma frequency that is well below their own emission frequency. © 2021, CC BY.

关键词： Calibration

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Preventive Soot Blowing Strategy based on State of Health Prediction for Coal-fired Power Plant Boiler

Preventive Soot Blowing Strategy based on State of Health Pr...

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第37届中国控制会议

作者： Yuanhao Shi Jie Wen Xiaoqiong Pang Jianfang Jia Fangshu Cui Jianchao Zeng Jingcheng Wang North University of China School of Electrical and Control Engineering North University of China School of Computer Science and Technology North University of ChinaSchool of Computer Science and Technology Shanghai Jiao Tong University Department of Automationand Key Laboratory of System Control and Information ProcessingMinistry of Education of China

This paper seeks the optimization of soot-blowing operations for heat transfer surfaces in coal-fired power plant boiler.A preventive soot blowing strategy based on state of health prediction for heat transfer surface was *** average state of health of heat transfer surface was forecasted as the threshold to draft preventive soot blowing *** to the theory of renewal process,an optimization model with the system prediction interval and the threshold of preventive soot blowing operation as the optimization variables and minimize average energy losses as the target function was *** using Particle Swarm Optimization（PSO）,the optimal preventive cycle and soot-blowing threshold were obtained,and the long-run average cost rate was the *** model is validated with experiment data of a 300 MW coal-fired power plant boiler and the parameters of prediction model are *** results can verify the feasibility of proposed *** can be used as the guide for the optimization of soot blowing in coal-fired power plant to improve the energy conservation level.

关键词： Coal-fired Boiler Heat Transfer Surface Soot-blowing State of Health（SOH） Prediction

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Solar wind current sheets and deHoffmann-Teller analysis: First results of DC electric field measurements by solar orbiter

arXiv

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arXiv 2021年

作者： Steinvall, K. Khotyaintsev, Yu.V. Cozzani, G. Vaivads, A. Yordanova, E. Eriksson, A.I. Edberg, N.J.T. Maksimovic, M. Bale, S.D. Chust, T. Krasnoselskikh, V. Kretzschmar, M. Lorfèvre, E. Plettemeier, D. Souček, J. Steller, M. Štverák, Š. Vecchio, A. Horbury, T.S. O'Brien, H. Evans, V. Fedorov, A. Louarn, P. Génot, V. André, N. Lavraud, B. Rouillard, A.P. Owen, C.J. Uppsala75121 Sweden Space and Plasma Physics Department of Physics and Astronomy Uppsala University Uppsala75120 Sweden Division of Space and Plasma Physics School of Electrical Engineering and Computer Science KTH Royal Institute of Technology Stockholm11428 Sweden LESIA Observatoire de Paris Université PSL CNRS Sorbonne Université Univ. Paris Diderot Sorbonne Paris Cité 5 place Jules Janssen Meudon92195 France Space Sciences Laboratory University of California BerkeleyCA United States Physics Department University of California BerkeleyCA United States LPP CNRS Ecole Polytechnique Sorbonne Université Observatoire de Paris Université Paris-Saclay Palaiseau Paris France LPC2E CNRS 3A avenue de la Recherche Scientifique Orléans France Université d'Orléans Orléans France CNES 18 Avenue Edouard Belin Toulouse31400 France Technische Universität Dresden Helmholtz Str. 10 DresdenD-01187 Germany Institute of Atmospheric Physics of the Czech Academy of Sciences Prague Czech Republic Space Research Institute Austrian Academy of Sciences Graz Austria Astronomical Institute of the Czech Academy of Sciences Prague Czech Republic Radboud Radio Lab Department of Astrophysics Radboud University Nijmegen Netherlands Imperial College London South Kensington Campus LondonSW7 2AZ United Kingdom Institut de Recherche en Astrophysique et Planétologie 9 Avenue du Colonel ROCHE BP 4346 Toulouse Cedex 431028 France Laboratoire d'Astrophysique de Bordeaux Univ. Bordeaux CNRS Pessac France Mullard Space Science Laboratory University College London Holmbury St. Mary Dorking SurreyRH5 6NT United Kingdom

Context. Solar Orbiter was launched on February 10, 2020 with the purpose of investigating solar and heliospheric physics using a payload of instruments designed for both remote and in-situ sensing. Similar to the recently launched Parker Solar Probe, and unlike earlier missions, Solar Orbiter carries instruments designed to measure the low frequency DC electric fields. Aims. In this paper we assess the quality of the low-frequency DC electric field measured by the Radio and plasma Waves instrument (RPW) on Solar Orbiter. In particular we investigate the possibility of using Solar Orbiter's DC electric and magnetic field data to estimate the solar wind speed. Methods. We use deHoffmann-Teller (HT) analysis based on measurements of the electric and magnetic fields to find the velocity of solar wind current sheets which minimizes a single component of the electric field. By comparing the HT velocity to proton velocity measured by the Proton and Alpha particle Sensor (PAS) we develop a simple model for the effective antenna length, Leff of the E-field probes. We then use the HT method to estimate the speed of the solar wind. Results. Using the HT method, we find that the observed variations in Ey are often in excellent agreement with the variations in the magnetic field. The magnitude of Ey, however, is uncertain due to the fact that the Leff depends on the plasma environment. We derive an empirical model relating Leff to the Debye length, which we can use to improve the estimate of Ey and consequently the estimated solar wind speed. Conclusions. The low frequency electric field provided by RPW is of high quality. Using deHoffmann-Teller analysis, Solar Orbiter's magnetic and electric field measurements can be used to estimate the solar wind speed when plasma data is unavailable. © 2021, CC BY.

关键词： Solar wind

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The effect of non-Markovian recovery on reversible failure propagation on networks

arXiv

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arXiv 2019年

作者： Lin, Zhaohua Feng, Mi Tang, Ming Liu, Zonghua Hui, Pak Ming Lai, Ying-Cheng Department of Physics East China Normal University Shanghai200062 China School of Information Science Technology East China Normal University Shanghai200241 China Web Sciences Center University of Electronic Science and Technology of China Chengdu611731 China Big Data Research Center University of Electronic Science and Technology of China Chengdu611731 China Shanghai Key Laboratory of Multidimensional Information Processing East China Normal University Shanghai200241 China Department of Physics Chinese University of Hong Kong Shatin Hong Kong School of Electrical Computer and Energy Engineering Arizona State University TempeAZ85287 United States

Compared with the classical irreversible failure propagation, the spontaneous recovery model can better depict the failure propagation on network systems such as financial and transportation networks. In this paper, we study how the non-Markovian recovery process influences cascading failure dynamics in the spontaneous recovery systems. To this end, we compare two kinds of failure-recovery models: the non-Markovian recovery (NMR) model and the corresponding Markovian recovery (MR) model. We first develop a Pairwise approximation theory for the MR and NMR models, which can predict the time evolution, steady state, and hysteresis behaviour of failure-recovery systems more accurately than the classical mean-field (MF) method. We find that although the non-Markovian recovery mechanism does not essentially affect the steady state and hysteresis behaviour of failure-recovery systems, the two models exhibit distinct evolution processes. When investigating the effect of initial conditions on the phase transition and hysteresis behavior, we find in the hysteresis region, the NMR model exhibits a non-monotonic growth characteristic: with the increase of initial failed nodes, the steady state staying in relative low-failure phase first turns into relative high-failure phase, and then into relative low-failure phase again. We then use the MF theory to explain the phenomenon qualitatively and point out when considering non-Markovian dynamics, we should study the steady state not only from the perspective of the variation of parameters, but also from the initial conditions. Copyright © 2019, The Authors. All rights reserved.

关键词： Hysteresis

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Linear synchronization and circuit implementation of chaotic system with complete amplitude control

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Chinese Physics B 2017年第12期26卷 124-133页

作者：李春彪 Wesley Joo-Chen Thio Julien Clinton Sprott 张若洵陆天爱 Jiangsu Key Laboratory of Meteorological Observation and Information Processing Nanjing University of Information Science & Technology Nanjing 210044 China School of Electronic & Information Engineering Nanjing University of Information Science & Technology Nanjing 210044 China Department of Electrical and Computer Engineering The Ohio State University Columbus OH 43210 USA Department of Physics University of Wisconsin-Madison Madison WI 53706 USA College of Teacher Education Xingtai University Xingtai 054001 China

Although chaotic signals are considered to have great potential applications in radar and communication engineering, their broadband spectrum makes it difficult to design an applicable amplifier or an attenuator for amplitude conditioning. Moreover, the transformation between a unipolar signal and a bipolar signal is often required. In this paper, a more intelligent hardware implementation based on field programmable analog array （FPAA） is constructed for chaotic systems with complete amplitude control. Firstly, two chaotic systems with complete amplitude control are introduced, one of which has the property of offset boosting with total amplitude control, while the other has offset boosting and a parameter for partial control. Both cases can achieve complete amplitude control including amplitude rescaling and offset boosting. Secondly, linear synchronization is established based on the special structure of chaotic system. Finally, experimental circuits are constructed on an FPAA where the predicted amplitude control is realized through only two independent configurable analog module （CAM） gain values.

关键词： complete amplitude control amplitude rescaling offset boosting linear synchronization

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Vandermonde Factorization of Hankel Matrix for Complex Exponential Signal Recovery — Application in Fast NMR Spectroscopy

arXiv

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arXiv 2018年

作者： Ying, Jiaxi Cai, Jian-Feng Guo, Di Tang, Gongguo Chen, Zhong Qu, Xiaobo Department of Electronic Science Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance Xiamen University Xiamen China Department of Mathematics Hong Kong University of Science and Technology Hong KongSAR China School of Computer and Information Engineering Xiamen University of Technology Xiamen China Department of Electrical Engineering & Computer Science Colorado School of Mines GoldenCO United States

Many signals are modeled as a superposition of exponential functions in spectroscopy of chemistry, biology and medical imaging. This paper studies the problem of recovering exponential signals from a random subset of samples. We exploit the Vandermonde structure of the Hankel matrix formed by the exponential signal and formulate signal recovery as Hankel matrix completion with Vandermonde factorization (HVaF). A numerical algorithm is developed to solve the proposed model and its sequence convergence is analyzed theoretically. Experiments on synthetic data demonstrate that HVaF succeeds over a wider regime than the state-of-the-art nuclear-norm-minimization-based Hankel matrix completion method, while has a less restriction on frequency separation than the state-of-the-art atomic norm minimization and fast iterative hard thresholding methods. The effectiveness of HVaF is further validated on biological magnetic resonance spectroscopy data. Copyright © 2018, The Authors. All rights reserved.

关键词： Matrix algebra

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