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arXiv 2020年

作者： Pham, Lam Phan, Huy Nguyen, Truc Palaniappan, Ramaswamy Mertins, Alfred McLoughlin, Ian University of Kent School of Computing Medway Kent United Kingdom Signal Processing and Speech Communication Lab Graz University of Technology Austria Institute for Signal Processing University of Lubeck Germany National Engineering Laboratory for Speech and Language Information Processing University of Science and Technology of China Hefei China

This article proposes an encoder-decoder network model for Acoustic Scene Classification (ASC), the task of identifying the scene of an audio recording from its acoustic signature. We make use of multiple low-level spectrogram features at the front-end, transformed into higher level features through a well-trained CNN-DNN front-end encoder. The high level features and their combination (via a trained feature combiner) are then fed into different decoder models comprising random forest regression, DNNs and a mixture of experts, for back-end classification. We report extensive experiments to evaluate the accuracy of this framework for various ASC datasets, including LITIS Rouen and IEEE AASP Challenge on Detection and Classification of Acoustic Scenes and Events (DCASE) 2016 Task 1, 2017 Task 1, 2018 Tasks 1A & 1B and 2019 Tasks 1A & 1B. The experimental results highlight two main contributions;the first is an effective method for high-level feature extraction from multi-spectrogram input via the novel C-DNN architecture encoder network, and the second is the proposed decoder which enables the framework to achieve competitive results on various datasets. The fact that a single framework is highly competitive for several different challenges is an indicator of its robustness for performing general ASC tasks. Copyright © 2020, The Authors. All rights reserved.

关键词： Classification (of information)

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Design of a New Sensor Integrating Scatterometer and SAR to Observe Sea Surface Wind Field

Design of a New Sensor Integrating Scatterometer and SAR to ...

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IEEE International Conference on radar

作者： Hang Li WenKang Liu GuangCai Sun MengDao Xing ZhenHua Zhang Jie Zhang The National Laboratory of Radar Signal Processing Xidian University Xi'an China Academy of Advanced Interdisciplinary Research Xidian University Xi'an China Ministry of Natural Resources Beijing Research Institute of Telemetry Ocean Telemetry Technology Innovation Center Beijing China Ministry of Natural Resources First Institute of Oceanography Ministry of Natural Resources Ocean Telemetry Technology Innovation Center Qingdao China

ISBN: (纸本)9781665468893

The sea surface wind vectors in different sea areas such as the general waters and offshore waters, change in different spatial scales and requires different resolutions. Due to different retrieving mechanisms, the scatterometer is suitable for observing wind fields with low resolution in general waters, while the SAR can be applied to obtain wind fields with higher resolution in offshore waters. In order to retrieve wind fields in all kinds of sea areas, this paper proposes a new sensor integrating scatterometer and SAR, which adopts a single digital array antenna, but functions as a SAR and a scatterometer simultaneously through multiple beamforming Besides, this paper designs the operating mode, together with the joint time sequence of the transceiver for two modes to work simultaneously. This proposed concept can benefit the system development in simpler architecture, lighter weight, and lower cost. Moreover, the multiple observation modes working synchronously can improve the retrieving accuracy, and may give birth to some new applications.

关键词： Sea surface Costs radar measurements Spaceborne radar radar scattering Transceivers Microwave antenna arrays

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Urban Environmental Sound Monitoring Network Based on Combination of Mobile and Stationary Nodes

Urban Environmental Sound Monitoring Network Based on Combin...

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International Conference on Information science and Control Engineering (ICISCE)

作者： Jinquan Wei Liyan Luo Mei Wang Xiyu Song Liujun Zhang Man Yao Guangxi Key Laboratory of Wireless Broadband Communication and Signal Processing Guilin University of Electronic Technology Guilin Guangxi Provincial Ministry of Education Key Laboratory of Cognitive Radio and Signal Processing Guilin University of Electronic Technology Guilin Guangxi College of Information Science and Engineering Guilin University of Technology Guilin Guangxi

Urban noise has posed a threat to people's physical and mental health. Significant progress has been made in noise monitoring related projects at home and abroad, but these projects usually utilize stationary monitoring equipment to measure noise whose deployment is susceptible to the cost and complex urban environment and thus they cannot effectively cover the monitored area. In this paper, a kind of joint mobile and stationary nodes based urban environmental sound monitoring network is proposed to achieve low-cost, high-precision, and high-flexibility noise monitoring. The network adopts NETTY framework, which effectively alleviates the impact of high concurrency on server performance in the context of large-scale sensor nodes. In addition, this paper designs a visual monitoring platform for the display of noise distribution and abnormal sound events. In order to verify the performance of the system, 10 mobile nodes and 50 stationary nodes are deployed in the campus environment. The experimental results show that the proposed system can realize urban environmental noise monitoring with high performance in real scenes.

关键词： Visualization Costs Working environment noise Urban areas Mobile nodes Servers Noise measurement

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Blind source extraction algorithm of LFM signal in given frequency modulation slope range

Blind source extraction algorithm of LFM signal in given fre...

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OCEANS

作者： Junjie Luo Cheng Chi Jiyuan Liu Chunhua Zhang University of Chinese Academy of Sciences Beijing China Key Laboratory of Science and Technology on Advanced Underwater Acoustic Signal Processing Chinese Academy of Sciences

ISBN: (数字)9781728154466

ISBN: (纸本)9781728184098

In highlight model, geometric highlights are often affected by elastic echoes. Based on “constrained blind source extraction” framework, an algorithm for LFM signal extraction in given frequency modulation slope (FMS) range is proposed. The cost function is constructed by combining negative entropy and interval constraint function, in addition, continuity and convergence are satisfied. The algorithm realizes extraction of the single source signal in specific FMS range. It is helpful to enhance the geometric highlights, which is of great significance to the subsequent target detection.

关键词： Frequency modulation signal processing algorithms Object detection Entropy Time-domain analysis Convergence signal to noise ratio

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On the Role of Priors in Bayesian Causal Learning

arXiv

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arXiv 2025年

作者： Geiger, Bernhard C. Kern, Roman Signal Processing and Speech Communication Laboratory Graz University of Technology Inf-feldgasse 16c Graz8010 Austria Know Center Research GmbH Sandgasse 34 Graz8010 Austria Institute for Interactive Systems and Data Science Graz University of Technology Sandgasse 36 Graz8010 Austria

In this work, we investigate causal learning of independent causal mechanisms from a Bayesian perspective. Confirming previous claims from the literature, we show in a didactically accessible manner that unlabeled data (i.e., cause realizations) do not improve the estimation of the parameters defining the mechanism. Furthermore, we observe the importance of choosing an appropriate prior for the cause and mechanism parameters, respectively. Specifically, we show that a factorized prior results in a factorized posterior, which resonates with Janzing and Schölkopf’s definition of independent causal mechanisms via the Kolmogorov complexity of the involved distributions and with the concept of parameter independence of Heckerman et al. Copyright © 2025, The Authors. All rights reserved.

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Experimental study of mode distortion induced by stimulated Raman scattering in high-power fiber amplifiers

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Photonics Research 2020年第4期8卷 595-600页

作者： QIUHUI CHU QIANG SHU ZENG CHEN FENGYUN LI DONGLIN YAN CHAO GUO HONGHUAN LIN JIANJUN WANG FENG JING CHUANXIANG TANG RUMAO TAO Research Center of Laser Fusion China Academy of Engineering PhysicsMianyang 621900China Key Laboratory of Particle&Radiation Imaging(Tsinghua University) Ministry of EducationDepartment of Engineering PhysicsTsinghua UniversityBeijing 100084China National Key Laboratory of Science and Technology on Blind Signal Processing Chengdu 610000China

The experimental investigation of mode distortion induced by stimulated Raman scattering(SRS)in a high-power fiber amplifier,which includes the evolutions of optical spectra,spatial beam profiles,and time-frequency characteristics,has been carried out in ***-frequency characteristics have been studied for the first time,to the best of our knowledge,by using a low-speed camera and high-speed photodiode traces,which revealed that temporal-frequency characteristics of SRS-induced mode distortion are different from traditional dynamic mode instability(MI).The experimental results show that the output beam profile remains stable before the mode distortion occurs and fluctuates obviously after the onset of SRS-induced MI but on a time scale of seconds,which is much lower than that of Yb-gain-induced MI featuring millisecond-level beam profile *** also shows that the mode distortion became measurable in company with the onset of inter-mode four-wave mixing(IM-FWM)when the ratio of Raman light reaches 3%;further,the beam quality factor M2degrades gradually from 1.4 to 2.1 as the ratio of Raman light *** mode distortion is accompanied by an obvious temperature increase of the output passive fiber,which further confirms that the mode distortion originates from *** cause of the mode distortion induced by SRS has been explained in the context of core-pumped SRS effect,and the investigation on the accompanying IM-FWM effect indicates that the main content of the SRSinduced high-order mode is the LP21 mode.

关键词： Experimental mode distortion stimulated Raman scattering in high-power fiber amplifiers Raman

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Pilot Optimization for OFDM-based OTFS Systems over Doubly Selective Channels

Pilot Optimization for OFDM-based OTFS Systems over Doubly S...

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GLOBECOM 2020 - 2020 IEEE Global Communications Conference

作者： Lei Zhao Wenbin Guo Yueliang Liu Jie Yang Wenbo Wang Science and Technology on Information Transmission and Dissemination in Communication Networks Laboratory Shijiazhuang China Wireless Signal Processing and Network Laboratory Beijing University of Posts and Telecommunications Beijing China

ISBN: (数字)9781728182988

ISBN: (纸本)9781728182995

For the orthogonal frequency division multiplexing-based orthogonal time-frequency-space (OFDM-based OTFS) systems, this paper studies the pilot optimization problem under the framework of distributed compressed sensing (DCS) and complex exponential basic extension model (CE-BEM). In order to reduce the inter-subcarrier interference (ICI) caused by the doubly selection (DS) channel and improve the accuracy of sparse channel estimation based on DCS, we propose pilot structure design and pilot pattern optimization schemes, respectively. First, we insert multiple sets of pilot clusters in the frequency domain OFDM symbols, where each set of pilot clusters contains an effective pilot and a guard pilot, and the data on both sides of the effective pilot is set equal to mitigate adjacent ICI. Then, through mutual coherence property, the optimization problem of effective pilot patterns in co-sparse symbols is transformed into a set of optimization problems of pilot interval, and a pilot pattern design algorithm based on pilot intervals is proposed. Finally, simulation results verify the effectiveness of the pilot structure design scheme, and the proposed algorithm not only has low computational complexity but also has superior system performance.

关键词： Channel estimation Optimization OFDM Matching pursuit algorithms Interference Indexes Time-frequency analysis

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Semi-Supervised Clustering via Information-Theoretic Markov Chain Aggregation

arXiv

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arXiv 2021年

作者： Steger, Sophie Geiger, Bernhard C. Śmieja, Marek Signal Processing and Speech Communication Laboratory Graz University of Technology Inffeldgasse 16c Graz8010 Austria Know-Center GmbH Inffeldgasse 13 Graz8010 Austria Faculty of Mathematics and Computer Science Jagiellonian University Lojasiewicza 6 Krakow Poland

We connect the problem of semi-supervised clustering to constrained Markov aggregation, i.e., the task of partitioning the state space of a Markov chain. We achieve this connection by considering every data point in the dataset as an element of the Markov chain's state space, by defining the transition probabilities between states via similarities between corresponding data points, and by incorporating semi-supervision information as hard constraints in a Hartigan-style algorithm. The introduced Constrained Markov Clustering (CoMaC) is an extension of a recent information-theoretic framework for (unsupervised) Markov aggregation to the semi-supervised case. Instantiating CoMaC for certain parameter settings further generalizes two previous information-theoretic objectives for unsupervised clustering. Our results indicate that CoMaC is competitive with the state-of-the-art. Furthermore, our approach is less sensitive to hyperparameter settings than the unsupervised counterpart, which is especially attractive in the semi-supervised setting characterized by little labeled data. Copyright © 2021, The Authors. All rights reserved.

关键词： Information theory

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A Target Detection Method in SAR Images Based on Superpixel Segmentation

A Target Detection Method in SAR Images Based on Superpixel ...

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IEEE International Conference on Electronic Information and Communication technology (ICEICT)

作者： Ming Liu Shichao Chen Fugang Lu Mengdao Xing Jingbiao Wei School of Computer Science Shaanxi Normal University Xi'an China Xi'an Modern Control Technology Research Institute Xi'an China National Laboratory of Radar Signal Processing Xidian University Xi'an China Army Aviation Research Institute Beijing China

ISBN: (数字)9781728190457

ISBN: (纸本)9781728190464

A synthetic aperture radar (SAR) target detection method based on the fusion of multiscale superpixel segmentations is proposed in this paper. SAR images are segmented between land and sea firstly by using superpixel technology in different scales. Secondly, image segmentation results together with the constant false alarm rate (CFAR) detection result are coalesced. Finally, target detection is realized by fusing different scale results. The effectiveness of the proposed algorithm is tested on Sentinel-1A data.

关键词： Image segmentation Conferences Object detection Detectors radar polarimetry Information and communication technology Synthetic aperture radar

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Steady-state Analysis of Bipolar Transistor

Steady-state Analysis of Bipolar Transistor

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Progress in Electromagnetic Research Symposium (PIERS)

作者： Yeqiang Yan Xingang Ren Shuping He Xiaotao Huang Zhixiang Huang Anhui Province Key Laboratory of Target Recognition and Feature Extraction Luan China Information Materials and Intelligent Sensing Laboratory of Anhui Province Institute of Physical Science and Information Technology Anhui University Hefei China Key Laboratory of Intelligent Computing & Signal Processing Ministry of Education Anhui University Hefei China Lingnan Normal University Zhanjiang China

ISBN: (纸本)9781665409889

Numerical simulation of semiconductor devices enable the quick obtain of the device physical characteristics. However, the trial productions of the semiconductor devices have the disadvantages of long cycle and high cost. Therefore, it is necessary to carry out numerical simulation investigating semiconductor devices. We propose the coupling approach and the decoupling-Gummel method to solve the semiconductor equations. The results of the two methods are compared with the commercial software. Numerical experiment indicates that the results obtained by our method are accurate. When the transistor is at a low voltage bias, the decoupling method converges faster than the coupling method. In the case of high voltage bias, the decoupling method has a slower convergence speed than the coupling method, even difficult to converge for higher voltage bias. However, the coupling method has higher memory requirements than the Gummel method. Therefore, we need to balance the advantages of the coupling method and the Gummel method when conduct the numerical simulation.

关键词： Couplings Bipolar transistors Voltage Production Numerical simulation Mathematical models Software

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