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Logarithm Radon-Fourier transform for high speed small target detection with atmospheric resistance effect

Digital Signal Processing 2025年 165卷

作者： Difeng Sun He Xu Zutang Wu Jin Li Youcao Wu Jianbing Li State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics and Information System College of Electronic Science and Technology National University of Defense Technology Changsha 410073 China National Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology Xi'an 710024 China Academy of Military Science of the People's Liberation Army Beijing 100071 China

Detecting high-speed, small targets in air is challenging due to their complex non-linear motion model and range migration effects. Traditional finite order polynomial models often fail to account for atmospheric drag accurately. This paper introduces a logarithmic relationship between range and time to model this motion, employing the Logarithmic Radon-Fourier Transform (LRFT) for accurately compensating the envelope and phase migration over extended accumulation periods. It offers both the ergodic search method and the fast implementation method for solving LRFT, along with a theoretical analysis of lobe location and amplitude. simulation results indicate that compared with traditional RFT-based methods, LRFT improves accumulation gain, enhances the main lobe's relative amplitude over sidelobes, and offers better detection performance in noisy environments. It provides more accurate recovery of target motion and improved target distinction capabilities. These benefits over traditional methods are especially evident when the product of the attenuation coefficient α , the initial velocity v 0 , and the total coherent accumulation time T M exceeds a specific threshold.

关键词： Fast Fourier transforms

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Surface tension of molten Al-Si alloy at temperatures ranging from 923 to 1123 K

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Chinese Science Bulletin 2008年第17期53卷 2593-2598页

作者： DOU Lei YUAN ZhangFu LI JianQiang LI Jing WANG XiaoQiang Department of Energy and Resources Engineering College of Engineering Peking University Beijing 100871 China State Key Laboratory of Multi-phase Complex System Institute of Process Engineering Chinese Academy of Sciences Beijing Graduate University of Chinese Academy of Sciences Beijing 100039 China

The surface tension of molten AlSi20 alloy has been measured by using the sessile drop method at 923―1123 K under argon atmosphere in both heating-up and cooling processes. The result shows that the surface tension of this alloy decreases as long as temperature increases. The results of surface tension and contact angles in heating-up process have differences from those obtained in cooling process, because the metal microstructures have some changes at different temperatures based on the metal genetic theory. The surface tension of molten AlSi20 alloy and that of molten pure aluminum have been compared as well, and the temperature coefficient of AlSi20 alloy is slightly lower than that of Al. The result has been analyzed by the linear scanning analysis with ESEM. The concentration of silicon in most region of the bulk is lower than that of the surface and the addition of Si to pure Al decreases the surface tension of molten pure Al.

关键词：铝硅合金表面张力温度变化金属材料

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Design of Modular Humanoid Rehabilitation Robot for Apoplectic Hemiplegia 29

Design of Modular Humanoid Rehabilitation Robot for Apoplect...

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第29届中国控制与决策会议

作者： Shuai Li Jian Li Siqi Li Guodong Li Yu Mu The Bionic Robot and System Key Laboratory School of Mechatronical EngineeringBeijing Institute of Technology Key Laboratory for Intelligent Control and Decision on Complex Systems School of AutomationBeijing Institute of Technology

ISBN: (纸本)9781509046584

Stroke is mainly caused by the brain damage due to the acute cerebral vascular disease and its primary disease,which can make upper limb or lower limb on one side of the body *** rehabilitation training is the most effective way to regain the Activities of Daily Living(ADL).Based on the concept of humanoid and modular design,this paper outlines the design process of humanoid ***,kinematics and dynamics are calculated in different coordinate frames,which makes simulation and control algorithms are more complex and not intuitive,for the forked-tree structure rehabilitation robot,a modified geometric description method of DH parameters is proposed to solve the problem of inconsistent frames,the whole body Jacobian matrix of this structure is derived and used for the inverse kinematics,and the singular configurations of redundant manipulator are *** important design criteria of humanoid robot is discussed,and the realization of the mechanical design is ***,the experimental results show that the humanoid robot can effectively carry out multiple parts rehabilitation training.

关键词： Rehabilitation Robot Humanoid robot Modularity Singularity Geometric Representation

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Design of a Flexible Capture Mechanism Inspired by Sea Anemone for Non-cooperative Targets

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Chinese Journal of Mechanical engineering 2021年第4期34卷 236-248页

作者： Jiankun Yang Chengwei Ren Chenghao Yang Youyu Wang Shumin Wan Rongjie Kang Key Laboratory of Mechanism Theory and Equipment Design of Ministry of Education Tianjin UniversityTianjin 300350China State Key Laboratory of Robotics Shenyang Institute of AutomationChinese Academy of SciencesShenyang 110169China Beijing Institute of Spacecraft System Engineering CAST Beijing 100094China

Robotic grippers have been used in industry as end-effectors but are usually limited to operations in pre-defined ***,few devices can capture irregularly shaped dynamic targets in space,underwater and other unstructured *** this paper,a novel continuum arm group mechanism inspired by the morphology and motions of sea anemones is *** is able to dissipate and absorb the kinetic energy of a fast moving target in omni-direction and utilize multiple arms to wrap and lock the target without accurate positioning ***-driven actuation systems are implemented in the individual continuum arms,achieving both bending motion and stiffness *** finite element method,the influence of different configurations of the continuum arm group on the capture performance is analyzed.A robotic prototype is constructed and tested,showing the presented arm group mechanism has high adaptability to capture targets with different sizes,shapes,and incident angles.

关键词： Non-cooperative targets Continuum arm group Wire-driven mechanism

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Stabilization of Perturbed Continuous-Time systems Using Event-Triggered Model Predictive Control

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IEEE Transactions on Cybernetics 2022年第5期52卷 4039-4051页

作者： Wang, Mengzhi Sun, Jian Chen, Jie Zhejiang University State Key Laboratory of Industrial Control Technology Hangzhou310027 China Beijing Institute of Technology Key Laboratory of Intelligent Control and Decision of Complex System Beijing100081 China Beijing Institute of Technology Chongqing Innovation Center Chongqing401120 China

In this article, event-triggered model predictive control (EMPC) of continuous-time nonlinear systems with bounded disturbances is studied. Two novel event-triggered control schemes are proposed. In the first strategy, an event-triggering condition, designed based on the state error between the actual system state and the optimal one, with an absolute threshold is considered. In the second strategy, an event-triggering condition with a mixed threshold is designed to further save the computational resources. The minimal interevent times of both event-triggered control schemes are obtained to avoid the Zeno behavior. Sufficient conditions of recursive feasibility for these two triggering strategies, which refer to the prediction horizon, the triggering level, and the disturbance bound, are obtained, respectively. Input-to-state practical stability (ISpS) of both event-triggered control systems is established without requiring the system state entering the terminal set in finite time, respectively. Finally, the numerical simulation shows the effectiveness of the proposed methods. © 2013 IEEE.

关键词： Model predictive control

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Satellite remote sensing of changes in NO_x emissions over China during 1996-2010

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Chinese Science Bulletin 2012年第22期57卷 2857-2864页

作者： ZHANG Qiang GENG GuanNan WANG SiWen RICHTER Andreas HE KeBin Ministry of Education Key Laboratory for Earth System Modeling and Center for Earth System ScienceTsinghua UniversityBeijing 100084China State Key Joint Laboratory of Environment Simulation and Pollution Control School of EnvironmentTsinghua UniversityBeijing 100084China Institute of Environmental Physics University of BremenBremen 28359Germany

Satellite derived NO2 column data have been used to study Chinese national fossil fuel consumption and pollutant *** on NO 2 retrievals from two satellites (GOME and SCIAMACHY) for 1996-2010,we analyzed the characteristics and evolution of regional pollution related to NO x emissions in *** observations indicated that the highly polluted regions were *** emission dominated areas have expanded from the east to central and western China,and new highly polluted regions have formed throughout the ***-up emission estimates suggested a 133% increase in anthropogenic NOx emissions in East Central China during 1996 to 2010,which was lower than the 184% increase of the NO2 columns measured by the *** found that growth rates of NOx emissions have slowed in Chinese megacities over recent years,in contrast to which,the NOx emissions were soaring in medium-sized cities,indicating that strict controls of NOx emissions from coal-fired facilities are required in China.

关键词：氮氧化物排放量卫星遥感中国污染物排放 NO2 燃料消耗卫星反演区域污染

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Effectiveness Evaluation of Communication Network based on BP neural network 5

Effectiveness Evaluation of Communication Network based on B...

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5th IEEE Information Technology, Networking, Electronic and Automation Control Conference, ITNEC 2021

作者： Han, Chi Xiong, Wei Jian, Ping Aerospace Engineering University Aerospace Information Institute Beijing China Aerospace Engineering University Science and Technology on Complex Electronic System Simulation Laboratory Beijing China

ISBN: (纸本)9781665415989

In order to solve the problem of effectiveness evaluation of military communication network (MCN) under complex application conditions, an intelligent evaluation method based on BP neural network is proposed. Based on the establishment of hierarchical evaluation index system, a neural network model is used to describe the mapping relationship between the index value and the overall effectiveness, and samples are extracted from experts' experience to train the neural network, so as to realize the intelligent evaluation and calculation of MCN's effectiveness. The simulation results show that this method has high accuracy, simplicity and can meet the requirements of MCN effectiveness evaluation under various military application conditions. © 2021 IEEE.

关键词： Neural networks

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Acoustic propagation uncertainty in internal wave environments using an ocean-acoustic joint model

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Chinese Physics B 2023年第3期32卷 308-319页

作者：高飞徐芳华李整林秦继兴章沁雅 Department of Earth System Science Ministry of Education Key Laboratory of Earth System ModelingInstitute for Global Change StudiesTsinghua UniversityBeijing 100084China Naval Research Institute Tianjin 300061China School of Ocean Engineering and technology Sun Yat-Sen UniversityZhuhai 519000China State Key Laboratory of Acoustics Institute of AcousticsChinese Academy of SciencesBeijing 100190China

An ocean-acoustic joint model is developed for research of acoustic propagation uncertainty in internal wave *** internal waves are numerically produced by tidal forcing over a continental slope using an ocean *** parameters(i.e.,internal wave,source depth,and water depth)contribute to the dynamic waveguide environments,and result in stochastic sound *** sensitivity of the transmission loss(TL)to environment parameters,statistical characteristics of the TL variation,and the associated physical mechanisms are investigated by the Sobol sensitivity analysis method,the Monte Carlo sampling,and the coupled normal mode theory,*** results show that the TL is most sensitive to the source depth in the near field,resulted from the initial amplitudes of higher-order modes;while in middle and far fields,the internal waves are responsible for more than 80%of the total acoustic propagation *** addition,the standard deviation of the TL in the near field and the shallow layer is smaller than those in the middle and far fields and the deep layer.

关键词： acoustic propagation uncertainty ocean-acoustic joint model internal wave sensitivity analysis

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Operational Effectiveness Evaluation of Space-based Information system based on Improved AHP-BPNN Model 5

Operational Effectiveness Evaluation of Space-based Informat...

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5th IEEE Information Technology, Networking, Electronic and Automation Control Conference, ITNEC 2021

作者： Han, Chi Xiong, Wei Jian, Ping Aerospace Information Institute Aerospace Engineering University Beijing China Science and Technology on Complex Electronic System Simulation Laboratory Aerospace Engineering University Beijing China

ISBN: (纸本)9781665415989

In view of the characteristics of complex influencing factors and coupling interaction of various combat capabilities in the effectiveness evaluation of space- based information system (SIS), the effectiveness evaluation method of SIS based on improved AHP-BP neural network was proposed, which was mapped to multi-attribute decision making problem. The weight of experts was determined from the objective perspective to improve the traditional AHP and calculate the relevant influencing factors among experts. The comprehensive evaluation value is obtained according to the evaluation matrix, and the comprehensive weight of the index is obtained by the weighted average of the expert weight and the index weight. The evaluation data obtained from improved AHP and combat simulation data are used as prior samples to train BPNN to obtain the effectiveness evaluation model. Finally, sample data were obtained through MATLAB and STK co-simulation to evaluate the operational effectiveness of SIS and verify the effectiveness of the model. © 2021 IEEE.

关键词： MATLAB

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Effectiveness Evaluation of Space-based Information system based on Improved SVR 5

Effectiveness Evaluation of Space-based Information System b...

引用

5th IEEE Information Technology, Networking, Electronic and Automation Control Conference, ITNEC 2021

ISBN: (纸本)9781665415989

The evaluation of effectiveness of space-based information system (SIS) is of great significance for modern warfare in integrated operations. In view of characteristics of complex impact factors, small number of samples and strong nonlinearity of effectiveness evaluation, support vector regression (SVR) is adopted to evaluate effectiveness. At the same time, cuckoo search optimizer (CSO) is introduced to optimize the three parameters of SVR. The simulation results indicate that improved SVR has higher accuracy than the traditional SVR and BP neural network, and can effectively evaluate the effectiveness of SIS. © 2021 IEEE.

关键词： Vector spaces

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