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High resolution inverse synthetic aperture radar imaging of three-axis-stabilized space target by exploiting orbital and sparse priors

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Chinese Physics B 2017年第10期26卷 459-471页

作者：马俊涛高梅国郭宝锋董健熊娣冯祺 School of information and electronics Beijing Institute of Technology Department of Electronic and Optical Engineering Ordnance Engineering college

The development of inverse synthetic aperture radar （ISAR） imaging techniques is of notable significance for moni- toring, tracking and identifying space targets in orbit. Usually, a well-focused ISAR image of a space target can be obtained in a deliberately selected imaging segment in which the target moves with only uniform planar rotation. However, in some imaging segments, the nonlinear range migration through resolution cells （MTRCs） and time-varying Doppler caused by the three-dimensional rotation of the target would degrade the ISAR imaging performance, and it is troublesome to realize accurate motion compensation with conventional methods. Especially in the case of low signal-to-noise ratio （SNR）, the estimation of motion parameters is more difficult. In this paper, a novel algorithm for high-resolution ISAR imaging of a space target by using its precise ephemeris and orbital motion model is proposed. The innovative contributions are as follows. 1） The change of a scatterer projection position is described with the spatial-variant angles of imaging plane calculated based on the orbital motion model of the three-axis-stabilized space target. 2） A correction method of MTRC in slant- and cross-range dimensions for arbitrarily imaging segment is proposed. 3） Coarse compensation for translational motion using the precise ephemeris and the fine compensation for residual phase errors by using sparsity-driven autofo- cus method are introduced to achieve a high-resolution ISAR image. Simulation results confirm the effectiveness of the proposed method.

关键词： space target ISAR imaging MTRC correction sparsity

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A novel evolving scale-free model with tunable attractiveness

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Chinese Physics B 2010年第7期19卷 35-39页

作者：刘绚刘天琪王昊李兴源 School of Electrical Engineering and Automation Sichuan University college of electronics and information Engineering Sichuan University

In this paper, a new evolving model with tunable attractiveness is presented. Based on the Barabasi-Albert （BA） model, we introduce the attractiveness of node which can change with node degree. Using the mean-field theory, we obtain the analytical expression of power-law degree distribution with the exponent γ∈ （3, ∞）. The new model is more homogeneous and has a lower clustering coefficient and bigger average path length than the BA model.

关键词： scale-free tunable attractiveness degree distribution clustering coefficient

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Research on spatial-variant property of bistatic ISAR imaging plane of space target

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Chinese Physics B 2015年第4期24卷 507-520页

作者：郭宝锋王俊岭高梅国尚朝轩傅雄军 Department of Electronic and Optical Engineering Ordance Engineering College School of information and electronics Beijing Institute of Technology

The imaging plane of inverse synthetic aperture radar （ISAR） is the projection plane of the target. When taking an image using the range-Doppler theory, the imaging plane may have a spatial-variant property, which causes the change of scatter＇s projection position and results in migration through resolution cells, In this study, we focus on the spatial-variant property of the imaging plane of a three-axis-stabilized space target. The innovative contributions are as follows. 1） The target motion model in orbit is provided based on a two-body model. 2） The instantaneous imaging plane is determined by the method of vector analysis. 3） Three Euler angles are introduced to describe the spatial-variant property of the imaging plane, and the image quality is analyzed. The simulation results confirm the analysis of the spatial-variant property. The research in this study is significant for the selection of the imaging segment, and provides the evidence for the following data processing and compensation algorithm.

关键词： space target bistatic ISAR imaging plane spatial-variant property

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Novel obstacle-avoiding path planning for crop protection UAV using optimized Dubins curve

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International Journal of Agricultural and Biological Engineering 2020年第4期13卷 172-177页

作者： Xihai Zhang Chengguo Fan Zhanyuan Cao Junlong Fang Yinjiang Jia college of electronics and information Northeast Agricultural UniversityHarbin 150000China

In recent years,the crop protection unmanned aerial vehicle(UAV)has been raised great attention around the world due to the advantages of more efficient operation and lower requirement of special landing ***,there are few researches on obstacle-avoiding path planning for crop protection *** this study,an improved Dubins curve algorithm was proposed for path planning with multiple obstacle ***,according to the flight parameters of UAV and the types of obstacles in the field,the obstacle circle model and the small obstacle model were ***,after selecting the appropriate Dubins curve to generate the obstacle-avoiding path for multiple obstacles,the genetic algorithm(GA)was used to search the optimal obstacle-avoiding ***,for turning in the path planning,a strategy considering the size of the spray width and the UAV’s minimum turning radius was presented,which could decrease the speed change *** results showed that the proposed algorithm can decrease the area of overlap and skip to 205.1%,while the path length increased by only 1.6%in comparison with the traditional Dubins obstacle-avoiding algorithm under the same *** the increase of obstacle radius,the area of overlap and skip reduced effectively with no significant increase in path ***,the algorithm can efficiently improve the validity of path planning with multiple obstacle constraints and ensure the safety of flight.

关键词： Dubins curve path planning genetic algorithm overlap and skip spray crop protection UAV

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Nonlinear correction of photoelectric displacement sensor based on least square support vector machine

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Journal of Central South University 2011年第5期18卷 1614-1618页

作者：郭杰荣何怡刚刘长青 college of Physics and electronics Hunan University of Arts and Science college of Electrical and information Engineering Hunan University

A model of correcting the nonlinear error of photoelectric displacement sensor was established based on the least square support vector *** parameters of the correcting nonlinear model,such as penalty factor and kernel parameter,were optimized by chaos genetic *** the nonlinear correction of photoelectric displacement sensor based on least square support vector machine was *** application results reveal that error of photoelectric displacement sensor is less than 1.5%,which is rather satisfactory for nonlinear correction of photoelectric displacement sensor.

关键词： least square support vector machine position photoelectric displacement sensor nonlinear correct

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Monotone positive solution for three-point boundary value problem

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Applied Mathematics(A Journal of Chinese Universities) 2008年第3期23卷 279-285页

作者： SUN Yong-ping college of electronics and information Zhejiang University of Media and Communications Hangzhou310018 China

In this paper, the existence of monotone positive solution for the following secondorder three-point boundary value problem is studied：x″（t）＋f（t,x（t））=0,0〈t〈1,x′（0）=0,x（1）＋δx′（η）=0,where η ∈ （0, 1）, δ∈ [0, ∞）, f ∈ C（[0, 1] × [0, ∞）, [0, ∞））. Under certain growth conditions on the nonlinear term f and by using a fixed point theorem of cone expansion and compression of functional type due to Avery, Anderson and Krueger, sufficient conditions for the existence of monotone positive solution are obtained and the bounds of solution are given. At last, an example is given to illustrate the result of the paper.

关键词： three-point boundary value problem fixed point theorem monotone positive solution

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The dynamical properties of a Rydberg hydrogen atom between two parallel metal surfaces

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Chinese Physics B 2011年第3期20卷 191-197页

作者：刘伟李洪云杨善迎林圣路 News Center University of Jinan Department of information Engineering Laiwu Vocational and Technical College college of Physics and electronics Shandong Normal University

This paper presents the dynamical properties of a Rydberg hydrogen atom between two metal surfaces using phase space analysis methods. The dynamical behaviour of the excited hydrogen atom depends sensitively on the atom-surface distance d. There exists a critical atom-surface distance dc = 1586 a.u. When the atom-surface distance d is larger than the critical distance de, the image charge potential is less important than the Coulomb potential, the system is near-integrable and the electron motion is regular. As the distance d decreases, the system will tend to be non-integrable and unstable, and the electron might be captured by the metal surfaces.

关键词： Poincare surfaces of section chaos the phase space analysis methods

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The detection method of low-rate DoS attack based on multi-feature fusion

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Digital Communications and Networks 2020年第4期6卷 504-513页

作者： Liang Liu Huaiyuan Wang Zhijun Wu Meng Yue college of electronics information and Automation Civil Aviation University of ChinaChina

As a new type of Denial of Service(DoS)attacks,the Low-rate Denial of Service(LDoS)attacks make the traditional method of detecting Distributed Denial of Service Attack(DDoS)attacks useless due to the characteristics of a low average rate and *** features extracted from the network traffic,a new detection approach based on multi-feature fusion is proposed to solve the problem in this *** attack feature set containing the Acknowledge character(ACK)sequence number,the packet size,and the queue length is used to classify normal and LDoS attack *** feature is digitalized and preprocessed to fit the input of the K-Nearest Neighbor(KNN)classifier separately,and to obtain the decision contour *** a posteriori probability in the matrix is fused,and the fusion decision index D is used as the basis of detecting the LDoS *** proved that the detection rate of the multi-feature fusion algorithm is higher than those of the single-based detection method and other algorithms.

关键词： Low-rate denial of service attacks Attack features KNN classifier Multi-feature fusion

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Study on the zero-state quantum responses for inductance coupled mesoscopic LC circuits

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Optoelectronics Letters 2010年第2期6卷 89-93页

作者：周小方白炳良郭海燕 Department of Physics and electronics information Engineering Zhangzhou Normal College

The exact solution of time-evolution operator is obtained by applying the gauge transformation of algebra *** an operator describes the time-evolution of the quantum state for two inductance coupled mesoscopic LC *** zero-state responses of the charge and current to the input voltage signal are *** results show that the system of inductance coupled mesoscopic LC circuits is linear and *** zero-state responses of the charge and current are consistent with those of the corresponding macroscopic circuit.

关键词：介观LC电路零状态响应耦合电感量子态反应时间演化线性时不变规范变换

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Semiclassical approximation for transmission through open Sinai billiards

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Chinese Physics B 2013年第2期22卷 128-132页

作者：蔡祥吉张延惠李宗良蒋国辉杨秦男徐学友 college of Physics and electronics Shandong Normal University information Research Institute Shandong Academy of Sciences

We use a semiclassical approximation to study the transport through the weakly open chaotic Sinai quantum billiards which can be considered as the schematic of a Sinai mesoscopic device,with the diffractive scatterings at the lead openings taken into *** conductance of the ballistic microstructure which displays universal fluctuations due to quantum interference of electrons can be calculated by Landauer formula as a function of the electron Fermi wave number,and the transmission amplitude can be expressed as the sum over all classical paths connecting the entrance and the exit *** the Sinai billiards,the path sum leads to an excellent numerical agreement between the peak positions of power spectrum of the transmission amplitude and the corresponding lengths of the classical trajectories,which demonstrates a good agreement between the quantum theory and the semiclassical theory.

关键词： Sinai billiards transmission amplitude classical trajectories power spectrum

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