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A method of line spectrum extraction based on target radiated spectrum feature and its post-processing

Journal of Systems Engineering and Electronics 2021年第6期32卷 1381-1393页

作者： DAI Wenshu ZHENG Enming BAO Kaikai Key Laboratory of Instrumentation Science&Dynamic Measurement North University of ChinaTaiyuan 030006China Institute of Acoustics Chinese Academy of SciencesBeijing 100190China Northern Institute of Automatic Control Technology Taiyuan 030051China

To improve the ability of detecting underwater targets under strong wideband interference environment,an efficient method of line spectrum extraction is proposed,which fully utilizes the feature of the target spectrum that the high intense and stable line spectrum is superimposed on the wide continuous *** method modifies the traditional beam forming algorithm by calculating and fusing the beam forming results at multi-frequency band and multi-azimuth interval,showing an excellent way to extract the line spectrum when the interference and the target are not in the same azimuth interval *** efficiency of the estimated azimuth variance and corresponding power of the line spectrum band depends on the line spectra ratio(LSR)of the line *** change laws of the output signal to noise ratio(SNR)with the LSR,the input SNR,the integration time and the filtering bandwidth of different algorithms bring the selection principle of the critical *** the basis,the detection gain of wideband energy integration and the narrowband line spectrum algorithm are theoretically *** simulation detection gain demonstrates a good match with the theoretical *** application conditions of all methods are verified by the receiver operating characteristic(ROC)curve and experimental data from Qiandao *** fact,combining the two methods for target detection reduces the missed detection *** proposed post-processing method in2-dimension with the Kalman filter in the time dimension and the background equalization algorithm in the azimuth dimension makes use of the strong correlation between adjacent frames,could further remove background fluctuation and improve the display effect.

关键词： towed linear array sonar target radiated noise spectrum line spectra level ratio(LSR) receiver operating characteristic(ROC)curve post-processing

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Sizing design and simulation of An SOFC propulsion system for unmanned aerial vehicles 17

Sizing design and simulation of An SOFC propulsion system fo...

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17th International Symposium on Solid Oxide Fuel Cells, SOFC 2021

作者： Tong, X. Wang, Y. Shi, Y. National Key Laboratory on Electromechanical Dynamic Control Beijing Institute of Technology Beijing100081 China Department of Energy and Power Engineering Tsinghua University Beijing100084 China

ISBN: (纸本)9781607685395

The short flight endurance is one of the key obstacles for the application of unmanned aerial vehicles (UAVs). Applying the fuel cells as the propulsion system of UAVs instead of batteries can increase the energy density and further lead to a longer cruise duration. Compared to other kinds of fuel cells, the solid oxide fuel cell (SOFC) is advantageous for its ability to use hydrocarbon fuels with a much higher energy storage density than hydrogen. In this paper, a SOFC propulsion system is sized and designed for UAV applications. The power allocation between the SOFC and energy storage components was further studied. A system model was developed, including an SOFC stack, a catalytic partial oxidation (CPOx) reformer, an after burner, and heat exchangers, etc. The design parameters of the SOFC stack and other components were selected to meet the power and energy demand of the UAV. The model is proved to be a useful tool for the design and simulation of the UAV-SOFC systems. © 2021 Electrochemical Society Inc.. All rights reserved.

关键词： Unmanned aerial vehicles (UAV)

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A New Design Using a Metal Wire Brush as the Current Collector of Micro-Tubular SOFCs 17

A New Design Using a Metal Wire Brush as the Current Collect...

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17th International Symposium on Solid Oxide Fuel Cells, SOFC 2021

作者： Shi, J. Fan, J. Wang, Y. Shi, Y. Cai, N. Department of Energy and Power Engineering Tsinghua University Beijing100084 China National Key Laboratory on Electromechanical Dynamic Control Beijing Institute of Technology Beijing100084 China

ISBN: (纸本)9781607685395

In this study, a novel current collecting method was designed and demonstrated by inserting a metal wire brush into the anode supported micro-tubular SOFC. The new design enables a tight and stable contact between the wire and the inner wall of the anode which leads to a fine performance of the SOFC. Different kinds of metal wires were applied, where the copper wire brush (CZWB) shows a better performance than the stainless steel wire brush (SSWB). At a temperature of 700 and a fuel feed of hydrogen, the SOFC using CZWB can achieve a maximum power density of 290 mW/cm2 and an ohmic resistance of 0.66 Ωcm2. And the brush size has been approved to have little effect on the ohmic resistance. A 108 h long-time discharge test was carried on, resulting with a degradation rate of 1.728‰/h and indicating a relative stability. © 2021 Electrochemical Society Inc.. All rights reserved.

关键词： Solid oxide fuel cells (SOFC)

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Localization of Pallets in Narrow Aisles for Unmanned Forklifts 3

Localization of Pallets in Narrow Aisles for Unmanned Forkli...

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3rd International Symposium on Computer technology and Information science, ISCTIS 2023

作者： Sun, Peng Ding, Wei Lian, Mingchang Chen, Hao Quanzhou Institute of Equipment Manufacturing Haixi Institutes Chinese Academy of Sciences Quanzhou362200 China Fujian Science & Technology Innovation Laboratory for Optoelectronic Information of China Fujian Fuzhou350108 China Fujian Provincial Key Laboratory of Intelligent Identification and Control of Complex Dynamic System Quanzhou362200 China

ISBN: (纸本)9798350325386

As the application of unmanned forklifts becomes more and more widespread, logistics scenarios are constantly evolving. This paper focuses on a scenario where the pick-up of pallets perpendicular to forklift in narrow aisles is required. The narrow aisles only allow the forklift to complete the turning, performing pallet localization in front of it will be difficult. We proposes a method for localizing pallets in narrow aisles for unmanned forklifts. By installing the camera at an oblique angle above the pallet, the collected images are uploaded to the image processing system. The YOLOv5 is used to detect the pallet and extract the bounding boxes of the pallet class. Based on the bounding box coordinates, the original image is cropped. Convert the cropped image to grayscale for Canny edge detection, and then perform Hough line detection to extract the right edge of the pallet. This right edge will be compared with the reference pallet edge to obtain the relative localization between the pallet and the unmanned forklift. © 2023 IEEE.

关键词： Feature extraction

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Elementary reaction kinetic model of an anode-supported syngas fueled solid oxide fuel cell considering the carbon deposition effect 17

Elementary reaction kinetic model of an anode-supported syng...

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17th International Symposium on Solid Oxide Fuel Cells, SOFC 2021

作者： Zhang, R. Wang, Y. Shi, Y. Wang, Y. Cao, H. National Key Laboratory on Electromechanical Dynamic Control Beijing Institute of Technology Beijing100081 China Department of Energy and Power Engineering Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing100084 China

ISBN: (纸本)9781607685395

A one-dimensional transient elementary reaction kinetic model of an anode supported solid oxide fuel cell (SOFC) fueled with syngas is developed considering the carbon deposition effect. This model incorporates the coupling effect of heterogeneous elementary chemical and electrochemical reactions, the electrode microstructure and the charge and mass transport processes. The model is validated by both experimental I-V curves and electrochemical impedance spectra. The simulation results agree reasonably well with the experimental data. The numerical results of carbon deposition simulation indicate that the surface carbon coverage can be decreased by increasing the operating temperature and reducing the carbon dioxide, methane or carbon monoxide in the fuel. © 2021 Electrochemical Society Inc.. All rights reserved.

关键词： Carbon monoxide

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A review of welding residual stress test methods

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China Welding 2022年第2期31卷 45-55页

作者： Gan Shiming Liu Huaying Zhai Zhiping Han Yongquan School of Mechanical Engineering Inner Mongolia University of TechnologyHohhot 010051China School of Materials Science and Engineering Inner Mongolia University of TechnologyHohhot 010051China Key Laboratory of electromechanical control of Inner Mongolia Autonomous Region Hohhot 010051China

Due to local uneven heating during the welding process,the residual stress of the structure after welding affects the reliability of *** order to ensure the reliability,it is of great significance to test the residual stress distribution of the welded *** has always been the focus to find a simple and feasible method for residual stress testing to quickly and accurately obtain the residual stress distribution of welded *** mechanical measurement method has high measurement accuracy,convenient and easy operation,but it will cause certain damage to the *** measurement method can avoid damage to components,but its test cost is usually high,and its measurement accuracy can also be affected by the material microstructure characteristics of welded *** on the advantages and disadvantages of these two residual stress test methods,a modal test method is *** method is a non-destructive measurement *** on the mathematical relationship between the residual stress of the welded structure and the natural frequency(mathematical model),the natural frequency is measured through the modal test to calculate the residual stress ***,it is difficult to establish a mathematical model with this method,and it is not suitable for realization.

关键词： welding residual stress mechanical measurement method physical measurement method modal test method

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Topological Defects Induced HighSpin Quartet State in Truxene-Based Molecular Graphenoids

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CCS Chemistry 2023年第3期5卷 695-703页

作者： Can Li Yu Liu Yufeng Liu Fu-Hua Xue Dandan Guan Yaoyi Li Hao Zheng Canhua Liu Jinfeng Jia Pei-Nian Liu Deng-Yuan Li Shiyong Wang Key Laboratory of Artificial Structures and Quantum Control Ministry of EducationShenyang National Laboratory for Materials ScienceSchool of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240 Key Laboratory for Advanced Materials and Feringa Nobel Prize Scientist Joint Research Center Frontiers Science Center for Materiobiology and Dynamic ChemistrySchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237 Tsung-Dao Lee Institute Shanghai Jiao Tong UniversityShanghai 200240 Shanghai Research Center for Quantum Sciences Shanghai 201315

Topological defects in graphene materials introduce exotic properties with both fundamental importance and technological implications,absent in their defect-free *** individual topological defects have been widely studied,collective magnetic behaviors originating from well-organized multiple topological defects remain a great ***,we examined the collective magnetic properties originating from three pentagon topological defects in truxene-based molecular graphenoids using scanning tunneling microscopy(STM)and non-contact atomic force ***πelectrons were introduced into the aromatic topology of truxene molecular graphenoids one by one by dissociating hydrogen atoms at the pentagon defects via atom *** measurements,together with density functional theory calculations,suggested that the unpaired electrons were ferromagnetically coupled,forming a collective highspin quartet state of S=3/*** work demonstrates that collective spin ordering could be realized through engineering regular patterned topological defects in molecular graphenoids,providing a new platform for designing one-dimensional ferromagnetic spin chains and two-dimensional ferromagnetic networks.

关键词： πelectron magnetism STM/nc-AFM highspin molecules atom manipulation surface chemistry

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Application of EMD combined with wavelet algorithm for filtering slag noise in steel cord conveyor belt

Application of EMD combined with wavelet algorithm for filte...

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2023 International Conference on Applied Statistics, Modeling and Advanced Algorithms, ASMA 2023

作者： Sun, Guoxin Zhang, Runze Liu, Zejiang Wu, Linfeng Yu, Qihui Tan, Xin School of Mechanical Engineering Inner Mongolia University of Science and Technology Baotou014010 China Key Laboratory of Intelligent Diagnosis and Control of Electromechanical Systems Inner Mongolia Autonomous Region Baotou014010 China Ordos Energy Research Institute Peking University Ordos017000 China

This study proposes a noise reduction technique that combines empirical mode decomposition (EMD) with wavelet thresholding to remove noise interference generated by metal slag in the damage signal of steel cord conveyor belts. The initial step involves decomposing the original signal into high-frequency and low-frequency intrinsic mode function (IMF) components using empirical mode decomposition (EMD), guided by the metal slag signal characteristics analysis. The high-frequency noise is filtered away while the low-frequency IMF components are kept intact through the wavelet threshold de-noising technique. The slag noise-containing IMF components are deleted, and the filtered signal and the low-frequency IMF components are utilized for signal reconstruction to provide the optimum noise reduction result. The study demonstrates that this method is more effective in suppressing metal slag noise, environmental noise, and other noise interferences than traditional EMD decomposition noise reduction and wavelet threshold noise reduction methods. This research provides a valuable reference for noise reduction in steel cord conveyor belt detection data. © Published under licence by IOP Publishing Ltd.

关键词： Intrinsic mode functions

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LK-ORB-SLAM3: An RGB-D Visual SLAM Algorithm Fusing Optical Flow Tracking and Feature Matching

LK-ORB-SLAM3: An RGB-D Visual SLAM Algorithm Fusing Optical ...

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Robotics, control and Automation Engineering (RCAE), International Conference on

作者： Juan Dai Shengqiang Sun Jingwei Liu Zhong Su Beijing Key Laboratory of High Dynamic Navigation Technology Beijing China Key Laboratory of Modern Measurement & Control Technology Ministry of Education Beijing China School of Automation Beijing Information Science & Technology University Beijing China

ISBN: (数字)9798350355642

ISBN: (纸本)9798350355659

In response to the issue of poor real-time performance caused by the large computational load of feature-based methods, this paper proposed an RGB-D visual SLAM algorithm which integrates optical flow and feature-based methods. This algorithm combined optical flow with the feature-based method, effectively improving the real-time performance of the algorithm while maintaining high precision. Firstly, keyframes are matched using feature-based methods, and camera motion is computed by minimizing the reprojection error. For non-keyframes, keypoints are extracted without computing descriptors and tracked using the optical flow pyramid, and pose estimation is achieved by minimizing the photometric error. Secondly, a dual mechanism based on time and space is employed to execute keyframes insertion which ensures tracking stability. Additionally, an adaptive threshold algorithm is proposed to enhance tracking robustness in low-light environments. Experimental results on the TUM dataset indicated that, with comparable average localization accuracy, the proposed algorithm reduces average tracking cost by 37.19%, achieving real-time frame rates of up to 45 fps on mid-to-low-performance CPUs.

关键词： Location awareness Visualization Costs Accuracy Simultaneous localization and mapping Tracking Heuristic algorithms Real-time systems Optical flow Robots

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Learn Topological Representation with Flexible Manifold Layer

Learn Topological Representation with Flexible Manifold Laye...

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International Conference on Acoustics, Speech, and Signal Processing (ICASSP)

作者： Ziheng Jiao Hongyuan Zhang Xuelong Li School of Computer Science Northwestern Polytechnical University Xi’an China School of Artificial Intelligence Optics and Electronics (iOPEN) Northwestern Polytechnical University Xi’an China Electromechanical Dynamic Control Laboratory China

Deep neural networks for classification are one of the most fundamental topics in machine learning. However, the widely used softmax decision layer, originating from the conventional softmax regression for multi-class classification, fails to guide the powerful feature extractor to explore the topological structure hidden in data, which limits the quality of produced representations. Therefore, we propose a flexible manifold layer for better representation learning in this paper, rather than adding some regularized losses to introduce extra mechanisms. The flexible manifold layer is inspired by SVM which maximizes the geometric margin and usually achieves better results than softmax regression. Since the potential structure is captured due to the explicit guidance of the proposed flexible manifold layer, the noise can be easily detected and filtered out via a designed automatic mechanism. In addition to passing the topological knowledge by latent representations, a knowledge distillation from the manifold layer and decision layer is developed. Extensive experiments show that the proposed model has achieved excellent performance. The code is available at https://***/jzh9830/DeepSVM.

关键词： Manifolds Deep learning Support vector machines Representation learning Neural networks Signal processing Feature extraction

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