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For LEO Satellite Networks: Intelligent Interference Sensing and Signal Reconstruction Based on Blind Separation Technology

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China Communications 2024年第2期21卷 85-95页

作者： Chengjie Li Lidong zhu Zhen Zhang The Key.Laboratory.for Computer Sy.tems of State Ethnic Affairs Commission School of Computer Science and Technology(Southwest Minzu University)Chengdu 610000China National Key.Laboratory.of Science and Technology.on Communications(University.of Electronic Science and Technology.of China) Chengdu 610000China College of Computer Science(Sichuan University. Chengdu 610000China

In LEO satellite communication networks,the number of satellites has increased sharply. the relative velocity.of satellites is very.fast, then electronic signal aliasing occurs from time to time. Those aliasing signals make the receiving ability.of the signal receiver worse, the signal processing ability.weaker,and the anti-interference ability.of the communication sy.tem lower. Aiming at the above problems, to save communication resources and improve communication efficiency. and considering the irregularity.of interference signals, the underdetermined blind separation technology.can effectively.deal with the problem of interference sensing and signal reconstruction in this scenario. In order to improve the stability.of source signal separation and the security.of information transmission, a greedy.optimization algorithm can be executed. At the same time, to improve network information transmission efficiency.and prevent algorithms from getting trapped in local optima, delete low-energy.points during each iteration process. Ultimately. simulation experiments validate that the algorithm presented in this paper enhances both the transmission efficiency.of the network transmission sy.tem and the security.of the communication sy.tem, achieving the process of interference sensing and signal reconstruction in the LEO satellite communication sy.tem.

关键词： blind source separation greedy.optimization algorithm interference sensing LEO satellite communication networks signal reconstruction

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Vector Radiative Transfer in a Vertically.Inhomogeneous Scattering and Emitting ***Ⅰ:A New Discrete Ordinate Method

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Journal of Meteorological Research 2024年第2期38卷 209-224页

作者： Ziqiang zhu Fuzhong WENG y.ng HAN Chinese Academy.of Meteorological Sciences China Meteorological AdministrationBeijing 100081 University.of Chinese Academy.of Sciences Beijing 100049 CMA Earth Sy.tem Modeling and Prediction Centre China Meteorological Administration(CMA)Beijing 100081 State Key.Laboratory.of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing 100081

The original vector discrete ordinate radiative transfer(VDISORT)model takes into account Stokes radiance vector but derives its solution assuming azimuthal sy.metric surface reflective matrix and atmospheric scattering phase matrix,such as the phase matrix derived from spherical particles or randomly.oriented non-spherical *** this study.a new VDISORT is developed for general atmospheric scattering and boundary.*** vector is decomposed into both sinusoidal and cosinusoidal harmonic modes,and the radiance at arbitrary.viewing geometry.is solved directly.by.adding two zero-weighted points in the Gaussian quadrature *** complex eigenvalues in homogeneous solutions are also taken into full *** accuracy.of VDISORT model is comprehensively.validated by.four cases:Ray.eigh scattering case,the spherical particle scattering case with the Legendre expansion coefficients of 0th-13th orders of the phase matrix(hereinafter L13),L13 with a polarized source,and the randomoriented oblate particle scattering case with the Legendre expansion coefficients of 0th-11th orders of the phase matrix(hereinafter L11).In all cases,the simulated radiances agree well with the benchmarks,with absolute biases less than 0.0065,0.0006,and 0.0008 for Ray.eigh,unpolarized L13,and L11,*** a polarized bidirectional reflection distribution function(pBRDF)matrix is used as the lower boundary.condition,VDISORT is now able to handle fully.coupled atmospheric and surface polarimetric radiative transfer processes.

关键词： radiative transfer discrete ordinate polarization Stokes vector vector discrete ordinate radiative transfer(VDISORT)

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Distributed order estimation for continuous-time stochastic sy.tems

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Control Theory.and Technology 2024年第3期22卷 406-418页

作者： Xinghua zhu Zhixin Liu Xiaoming Hu Key.Laboratory.of Sy.tems and Control Academy of Mathematics and Systems ScienceBeijing 100190China School of Mathematical Sciences University of Chinese Academy of SciencesBeijing 100190China Department of Mathematics KTH Royal Institute of TechnologyStockholm 10044Sweden

In this paper,we investigate the distributed estimation problem of continuous-time stochastic dy.amic sy.tems over sensor networks when both the sy.tem order and parameters are *** propose a local information criterion(LIC)based on the L_(0)penalty.*** minimizing LIC at the diffusion time instant and utilizing the continuous-time diffusion least squares algorithm,we obtain a distributed estimation algorithm to simultaneously.estimate the unknown order and the parameters of the *** dealing with the effect of the sy.tem noises and the coupling relationship between estimation of sy.tem orders and parameters,we establish the almost sure convergence results of the proposed distributed estimation ***,we give a simulation example to verify.the effectiveness of the distributed algorithm in estimating the sy.tem order and parameters.

关键词： Stochastic differential equations Sensor networks Distributed order estimation Cooperative excitation condition.Convergence

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Mitigation of Optical Multipath Interference Algorithms in IM-DD Transmission Sy.tem

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China Communications 2024年第4期21卷 1-9页

作者： Huo Jiahao zhu Jin zhu Zuqing Zhang Xiaoy.ng Liu Shaonan Tao Jianlong Wei Huangfu School of Computer and Communication Engineering University of Science and Technology BeijingBeijing 100083China School of Information Science and Technology University of Science and Technology of ChinaHefei 230026China

This paper aimed to propose two algorithms,DA-M and RF-M,of reducing the impact of multipath interference(MPI)on intensity.modulation direct detection(IM-DD)sy.tems,particularly.for four-level pulse amplitude modulation(PAM4)***-M reduced the fluctuation by.averaging the signal in blocks,RF-M estimated MPI by.subtracting the decision value of the corresponding block from the mean value of a signal block,and then generated interference-reduced samples by.subtracting the interference signal from the product of the corresponding MPI estimate and then weighting *** paper firstly.proposed to separate the signal before decision-making into multiple blocks,which significantly.reduced the complexity.of DA-M and *** results showed that the MPI noise of 28 GBaud IMDD sy.tem under the linewidths of 1e5 Hz,1e6 Hz and 10e6 Hz can be effectively.alleviated.

关键词： IM-DD multipath interference PAM4

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Lateral photovoltaic effect in the Ni-SiO_(2)-Si structure with bias

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Optoelectronics Letters 2024年第5期20卷 257-264页

作者： LING Xiang zhu Pengfei zhu Kun SONG Pei LI Xiong School of Mathematics Physics and StatisticsShanghai University of Engineering ScienceShanghai 201600China School of Electrical Engineering Liupanshui Normal UniversityLiupanshui 553004China School of Railway.Telecommunication Hunan Technical College of Railway High-speedHengyang 421002China

We designed a clamping device to study.lateral photovoltaic effect (LPE) in Ni-SiO_(2)-Si structure with bias due to the appropriate barrier *** LPE has a prominent sensitivity.and linearity.with 532 nm wavelength *** transient response time is 450μs and the relaxation time is 2 250μs in the Ni-SiO_(2)-Si structure without *** LPE sensitivity.has a significant improvement with *** transient response time is 6μs and the relaxion time is 47μs with-7 V bias,not only.improving the LPE sensitivity.but also increasing the response speed with *** research shows that the Schottky.barrier structure can improve the sensitivity.and linearity.of LPE with bias effectively.and thus it can be used in position sensitive sensors.

关键词： LPE structure effect

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The Effects of the Geometry.of a Current Collector with an Equal Open Ratio on Output Power of a Direct Methanol Fuel Cell

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Energy.Engineering 2024年第5期121卷 1161-1172页

作者： y.ngli zhu Jiachi Xie Mingwei zhu Jun Zhang Miaomiao Li Tianjin Key.Laboratory.of Integrated Design and On-line Monitoring for Light Industry.Food Machinery.and Equipment School of Mechanical EngineeringTianjin University of Science&TechnologyTianjin300222China Tianjin College University of Science and Technology BeijingTianjin301830China Jiangsu Key.Laboratory.of Precision and Micro-Manufacturing Technology College of Mechanical and Electrical EngineeringNanjing University of Aeronautics and AstronauticsNanjing210016China

The open ratio of a current collector has a great impact on direct methanol fuel cell(DMFC)*** a number of studies have investigated the influence of the open ratio of DMFC current collectors,far too little attention has been given to how geometry.including the shape and feature size of the flow field)affects a current collector with an equal open *** this paper,perforated and parallel current collectors with an equal open ratio of 50%and different feature sizes are designed,and the corresponding experimental results are shown to explain the geometry.effects on the output power of the *** results indicate that the optimal feature sizes are between 2 and 2.5 mm for both perforated and parallel flow field in the current collectors with an equal open ratio of 50%.This means that for passive methanol fuel cells,to achieve the highest output power,the optimal feature size of the flow field in both anode and cathode current collectors is between 2 and 2.5 mm under the operating mode of this *** effects of rib and channel position are also investigated,and the results indicate that the optimum pattern depends on the feature sizes of the flow field.

关键词： Direct methanol fuel cell geometry open ratio current collector position

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Optimal Energy.Efficiency.Based High-speed Fly.ng Control Method for Hy.raulic Quadruped Robot

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Journal of Bionic Engineering 2024年第3期21卷 1156-1173页

作者： Qingjun y.ng Zheny.ng Zhang Rui zhu Dianxin Wang School of Mechatronics Engineering Harbin Institute of TechnologyHarbin150000China Nanjing Chenguang Group Co.Ltd Nanjing210006China

Herein,a control method based on the optimal energy.efficiency.of a hy.raulic quadruped robot was proposed,which not only.realizes the optimal energy.efficiency.of fly.ng trot gait but also ensures the stability.of high-speed ***,the energy.consumption per unit distance was adopted as the energy.efficiency.evaluation index based on the constant pressure oil supply.characteristics of the hy.raulic sy.tem,and the global optimization algorithm was adopted to solve the optimal ***,the gait parameters that affect the energy.efficiency.of quadruped were analy.ed and the mapping relationship between each parameter and energy.efficiency.was captured,so as to select the optimum combination of energy.efficiency.parameters,which is significant to improve endurance ***,to ensure the stability.of the high-speed fly.ng trot gait motion of the hy.raulic quadruped robot,the active compliance control strategy.was ***,the proposed method was successfully.verified by.simulations and *** experimental results reveal that the fly.ng trot gait of the hy.raulic quadruped robot can be stably.controlled at a speed of 2.2 m/s.

关键词： Hy.raulic quadruped robot Fly.ng trot Energy.efficiency Active compliance control

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Fast solution to the free return orbit's reachable domain of the manned lunar mission by.deep neural network

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Journal of Sy.tems Engineering and Electronics 2024年第2期35卷 495-508页

作者： y.NG Luy. LI Haiy.ng ZHANG Jin zhu y.ehe College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China China Astronauts Research and Training Center Beijing 100094China Hunan Key.Laboratory.of Intelligent Planning and Simulation for Aerospace Missions Changsha 410073China

It is important to calculate the reachable domain(RD)of the manned lunar mission to evaluate whether a lunar landing site could be reached by.the spacecraft. In this paper, the RD of free return orbits is quickly.evaluated and calculated via the classification and regression neural networks. An efficient databasegeneration method is developed for obtaining eight ty.es of free return orbits and then the RD is defined by.the orbit’s inclination and right ascension of ascending node(RAAN) at the perilune. A classify.neural network and a regression network are trained respectively. The former is built for classify.ng the ty.e of the RD, and the latter is built for calculating the inclination and RAAN of the RD. The simulation results show that two neural networks are well trained. The classification model has an accuracy.of more than 99% and the mean square error of the regression model is less than 0.01°on the test set. Moreover, a serial strategy.is proposed to combine the two surrogate models and a recognition tool is built to evaluate whether a lunar site could be reached. The proposed deep learning method shows the superiority.in computation efficiency.compared with the traditional double two-body.model.

关键词： manned lunar mission free return orbit reachable domain(RD) deep neural network computation efficiency

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The Exchange Attack and the Mixture Differential Attack Revisited: From the Perspective of Automatic Evaluation

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Chinese Journal of Electronics 2024年第1期33卷 19-29页

作者： Kexin QIAO Zhiy. ZHANG Zhongfeng NIU Liehuang zhu School of Cy.erspace Science and Technology Beijing Institute of Technology State Key.Laboratory.of Cry.tology Institute of Information Engineering Chinese Academy of Sciences School of Cry.tography University of Chinese Academy of Sciences

Recent results show that the differential properties within quadruples boom as a new inspiration in cry.tanaly.is of Advanced Encry.tion Standard(AES)-like constructions. These methods include the exchange attack proposed in Asiacry.t’19, the mixture differential attack proposed in To SC’18, etc., where the essential properties are obtained by.manually.scrutinizing the structures of the AES-like constructions. This paper presents a novel framework and an automatic tool based on mixed integer linear programming to search for mixture differential distinguishers for general constructions. This framework considers what equality.patterns among quadruples can make a distinguisher and traces how the patterns propagate through cipher components with accurate probability.*** this tool, a 5-round AES distinguishing attack with lower complexity.and more 6-round distinguishing attacks in the chosen plaintext scenarios are deduced. We prove that no exchange-ty.e or mixture differential distinguisher exists for 7 and above rounds AES if the details of the Sbox and Mix Columns matrix are not taken into account.

关键词： Ciphers Estimation Encry.tion Mixed integer linear programming Complexity.theory Standards

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Analy.ical computation of magnetic field in coil-dominated superconducting quadrupole magnets based on racetrack coils

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Nuclear Science and Techniques 2024年第4期35卷 119-135页

作者： Chuang Shen y.ng-Shun zhu Fu-San Chen China Spallation Neutron Source Institute of High Energy PhysicsChinese Academy of Sciences1 Zhongziyuan RoadDongguan 523000China Institute of High Energy.Phy.ics Chinese Academy of Sciences19B Yuquan RoadBeijing 100049China University.of Chinese Academy.of Sciences Beijing 100049China

Currently.three ty.es of superconducting quadrupole magnets are used in particle accelerators:cos 2θ,CCT,and ***,all three coil configurations have complex spatial geometries,which make magnet manufacturing and strain-sensitive superconductor applications *** with the three existing quadrupole coils,the racetrack quadrupole coil has a simple shape and manufacturing process,but there have been few theoretical *** this paper,the two-dimensional and three-dimensional analy.ical expressions for the magnetic field in coil-dominated racetrack superconducting quadrupole magnets are *** analy.ical expressions of the field harmonics and gradient are fully.resolved and depend only.on the geometric parameters of the coil and current ***,a genetic algorithm is applied to obtain a solution for the coil geometry.parameters with field harmonics on the order of 10^(-4).Finally.considering the practical engineering needs of the accelerator interaction region,electromagnetic design examples of racetrack quadrupole magnets with high gradients,large apertures,and small apertures are described,and the application prospects of racetrack quadrupole coils are analy.ed.

关键词： Superconducting quadrupole magnet Racetrack coil Multipole field Genetic algorithm Magnetic design

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