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Variable dimensional state space based global path planning for mobile robot 被引量:1
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作者 张浩杰 陈慧岩 +6 位作者 姜岩 龚建伟 熊光明 陈慧岩 姜岩 龚建伟 熊光明 《Journal of Beijing Institute of Technology》 EI CAS 2012年第3期328-335,共8页
A variable dimensional state space(VDSS) has been proposed to improve the re-planning time when the robotic systems operate in large unknown environments.VDSS is constructed by uniforming lattice state space and gri... A variable dimensional state space(VDSS) has been proposed to improve the re-planning time when the robotic systems operate in large unknown environments.VDSS is constructed by uniforming lattice state space and grid state space.In VDSS,the lattice state space is only used to construct search space in the local area which is a small circle area near the robot,and grid state space elsewhere.We have tested VDSS with up to 80 indoor and outdoor maps in simulation and on segbot robot platform.Through the simulation and segbot robot experiments,it shows that exploring on VDSS is significantly faster than exploring on lattice state space by Anytime Dynamic A*(AD*) planner and VDSS is feasible to be used on robotic systems. 展开更多
关键词 variable dimensional state space lattice state space Anytime Dynamic A*(AD*) path planning
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Electromagnetic effects on the orbital motion of a charged spacecraft
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作者 Yehia Ahmed Abdel-Aziz Khalil Ibrahim Khalil 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第5期589-600,共12页
This paper deals with the effects of electromagnetic forces on the orbital motion of a spacecraft. The electrostatic charge which a spacecraft generates on its surface in the Earth's magnetic field will be subject to... This paper deals with the effects of electromagnetic forces on the orbital motion of a spacecraft. The electrostatic charge which a spacecraft generates on its surface in the Earth's magnetic field will be subject to a perturbative Lorentz force. A model incorporating all Lorentz forces as a function of orbital elements has been developed on the basis of magnetic and electric fields. This Lorentz force can be used to modify or perturb the spacecraft's orbits. Lagrange's planetary equations in the Gauss variational form are derived using the Lorentz force as a perturbation to a Keplerian orbit. Our approach incorporates orbital inclination and the true anomaly. The numer- ical results of Lagrange's planetary equations for some operational satellites show that the perturbation in the orbital elements of the spacecraft is a second order perturba- tion for a certain value of charge. The effect of the Lorentz force due to its magnetic component is three times that of the Lorentz force due to its electric component. In addition, the numerical results confirm that the strong effects are due to the Lorentz force in a polar orbit, which is consistent with realistic physical phenomena that occur in polar orbits. The results confirm that the magnitude of the Lorentz force depends on the amount of charge. This means that we can use artificial charging to create a force to control the attitude and orbital motion of a spacecraft. 展开更多
关键词 space vehicles -- atmospheric effects -- celestial mechanics -- kine-matics and dynamics
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Preparation of Hadamard Gate for Open Quantum Systems by the Lyapunov Control Method 被引量:2
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作者 Nourallah Ghaeminezhad Shuang Cong 《IEEE/CAA Journal of Automatica Sinica》 SCIE EI CSCD 2018年第3期733-740,共8页
In this paper, the control laws based on the Lyapunov stability theorem are designed for a two-level open quantum system to prepare the Hadamard gate, which is an important basic gate for the quantum computers. First,... In this paper, the control laws based on the Lyapunov stability theorem are designed for a two-level open quantum system to prepare the Hadamard gate, which is an important basic gate for the quantum computers. First, the density matrix interested in quantum system is transferred to vector formation.Then, in order to obtain a controller with higher accuracy and faster convergence rate, a Lyapunov function based on the matrix logarithm function is designed. After that, a procedure for the controller design is derived based on the Lyapunov stability theorem. Finally, the numerical simulation experiments for an amplitude damping Markovian open quantum system are performed to prepare the desired quantum gate. The simulation results show that the preparation of Hadamard gate based on the proposed control laws can achieve the fidelity up to 0.9985 for the different coupling strengths. 展开更多
关键词 Lyapunov control method open quantum system operator preparation quantum Hadamard gate vector space dynamics
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Radiation reaction induced spiral attractors in ultra-intense colliding laser beams 被引量:2
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作者 Zheng Gong Ronghao Hu +5 位作者 Yinren Shou Bin Qiao Chiaer Chen Furong Xu Xiantu He Xueqing Yan 《Matter and Radiation at Extremes》 SCIE EI CAS 2016年第6期308-315,共8页
The radiation reaction effects on electron dynamics in counter-propagating circularly polarized laser beams are investigated through the linearization theorem and the results are in great agreement with numeric soluti... The radiation reaction effects on electron dynamics in counter-propagating circularly polarized laser beams are investigated through the linearization theorem and the results are in great agreement with numeric solutions.For the first time,the properties of fixed points in electron phase-space were analyzed with linear stability theory,showing that center nodes will become attractors if the classical radiation reaction is considered.Electron dynamics are significantly affected by the properties of the fixed points and the electron phase-space densities are found to be increasing exponentially near the attractors.The density growth rates are derived theoretically and further verified by particle-in-cell sim-ulations,which can be detected in experiments to explore the effects of radiation reaction qualitatively.The attractor can also facilitate realizing a series of nanometer-scaled flying electron slices via adjusting the colliding laser frequencies. 展开更多
关键词 Radiation reaction effect Phase space dynamics PIC simulation
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A Linear Domain System Identification for Small Unmanned Aerial Rotorcraft Based on Adaptive Genetic Algorithm 被引量:12
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作者 Xusheng Lei,Yuhu Du School of the Instrumentation Science and Opto-Electronic Engineering,Beihang University,Beijing 100191,P.R.China 《Journal of Bionic Engineering》 SCIE EI CSCD 2010年第2期142-149,共8页
This paper proposes a new adaptive linear domain system identification method for small unmanned aerial rotorcraft.Byusing the flash memory integrated into the micro guide navigation control module, system records the... This paper proposes a new adaptive linear domain system identification method for small unmanned aerial rotorcraft.Byusing the flash memory integrated into the micro guide navigation control module, system records the data sequences of flighttests as inputs (control signals for servos) and outputs (aircraft’s attitude and velocity information).After data preprocessing, thesystem constructs the horizontal and vertical dynamic model for the small unmanned aerial rotorcraft using adaptive geneticalgorithm.The identified model is verified by a series of simulations and tests.Comparison between flight data and the one-stepprediction data obtained from the identification model shows that the dynamic model has a good estimation for real unmannedaerial rotorcraft system.Based on the proposed dynamic model, the small unmanned aerial rotorcraft can perform hovering,turning, and straight flight tasks in real flight tests. 展开更多
关键词 small unmanned aerial rotorcraft dynamic space model model identification adaptive genetic algorithm
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Beam dynamics study of RFQ for CADS with a 3D space-charge-effect
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作者 李超 张智磊 +3 位作者 齐新 徐显波 何源 杨磊 《Chinese Physics C》 SCIE CAS CSCD 2014年第3期78-83,共6页
The ADS(accelerator driven subcritical system) project was proposed by the Chinese Academy of Sciences.The initial proton beams delivered from an electron cyclotron resonance ion source can be effectively accelerate... The ADS(accelerator driven subcritical system) project was proposed by the Chinese Academy of Sciences.The initial proton beams delivered from an electron cyclotron resonance ion source can be effectively accelerated by 162.5 MHz 4.2 m long room temperature radio-frequency-quadrupoles(RFQ) operating in CW mode.To test the feasibility of this physical design,a new Fortran code for RFQ beam dynamics study,which is space charge dominated,was developed.This program is based on Particle-In-Cell(PIC) technique in the time domain.Using the RFQ structure designed for the CADS project,the beam dynamics behavior is performed.The well-known simulation code TRACK is used for benchmarks.The results given by these two codes show good agreements.Numerical techniques as well as the results of beam dynamics studies are presented in this paper. 展开更多
关键词 accelerator RFQ PIC beam dynamics simulation space charge Poisson's equation
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Equilibria of a charged artificial satellite subject to gravitational and Lorentz torques
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作者 Yehia A.Abdel-Aziz Muhammad Shoaib 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2014年第7期891-902,共12页
The attitude dynamics of a rigid artificial satellite subject to a gravity gradient and Lorentz torques in a circular orbit are considered. Lorentz torque is developed on the basis of the electrodynamic effects of the... The attitude dynamics of a rigid artificial satellite subject to a gravity gradient and Lorentz torques in a circular orbit are considered. Lorentz torque is developed on the basis of the electrodynamic effects of the Lorentz force acting on the charged satellite's surface. We assume that the satellite is moving in a Low Earth Orbit in the geomagnetic field, which is considered to be a dipole. Our model of torque due to the Lorentz force is developed for an artificial satellite with a general shape, and the nonlinear differential equations of Euler are used to describe its attitude orientation. All equilibrium positions are determined and conditions for their existence are obtained.The numerical results show that the charge q and radius ρ0of the center of charge for the satellite provide a certain type of semi-passive control for the attitude of the satellite. The technique for this kind of control would be to increase or decrease the electrostatic screening on the satellite. The results obtained confirm that the change in charge can affect the magnitude of the Lorentz torque, which can also affect control of the satellite. Moreover, the relationship between magnitude of the Lorentz torque and inclination of the orbit is investigated. 展开更多
关键词 space vehicles -- atmospheric effects -- celestial mechanics -- kine-matics and dynamics
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The Maximum Dissipative Extension of Schrodinger Operator
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作者 田立新 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI 1994年第10期973-980,共8页
In the present paper we study the maximum dissipative extension of Schrodingeroperator.introduce the generalized indefinite metvic space and get the representation ofmaximum dissipative extension of Schrodinger operat... In the present paper we study the maximum dissipative extension of Schrodingeroperator.introduce the generalized indefinite metvic space and get the representation ofmaximum dissipative extension of Schrodinger operator in natural boundary space.make preparation for the further study longtime chaotic behaxior of infinite dimensiondynamics system in nonlinear Schrodinger equation. 展开更多
关键词 infinite dimension dynamics system. nonlinear Schfrodingerequation. indefinite metric space. dissipative operator
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A Dual-driven Intelligent Combination Control of Heat Pipe Space Cooling System 被引量:4
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作者 LI Yunze LI Mingmin LEE Kok Meng 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2012年第4期566-574,共9页
Effective thermal control systems are essential for reliable operation of spacecraft.A dual-driven intelligent combination control strategy is proposed to improve the temperate control and heat flux tracking effects.B... Effective thermal control systems are essential for reliable operation of spacecraft.A dual-driven intelligent combination control strategy is proposed to improve the temperate control and heat flux tracking effects.Both temperature regulation and heat flux tracking errors are employed to generate the final control action;their contributions are adaptively adjusted by a fuzzy fusing policy of control actions.To evaluate the control effects,describe a four-nodal mathematical model for analyzing the dynamic characteristics of the controlled heat pipe space cooling system(HP-SCS) consisting of an aluminum-ammonia heat pipe and a variable-emittance micro-electromechanical-system(MEMS) radiator.This dynamical model calculates the mass flow-rate and condensing pressure of the heat pipe working fluid directly from the systemic nodal temperatures,therefore,it is more suitable for control engineering applications.The closed-loop transient performances of four different control schemes have been numerically investigated.The results conclude that the proposed intelligent combination control scheme not only improves the thermal control effects but also benefits the safe operation of HP-SCS. 展开更多
关键词 heat pipe space cooling system dynamic modeling intelligent combination control micro-electromechanical-system
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A STATE SPACE ISOMORPHISM THEOREM F0R MINIMAL DYNAMICAL SYSTEMS
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作者 W.P.DAYAWANSA C.F.MARTIN D.CHENG 《Acta Mathematicae Applicatae Sinica》 SCIE CSCD 1991年第1期34-37,共4页
Consider a discrete time dynamical system x_(k+1)=f(x_k) on a compact metric space M, wheref: M→M is a continuous map. Let h:M→R^k be a continuous output function. Suppose that all ofthe positive orbits of f are den... Consider a discrete time dynamical system x_(k+1)=f(x_k) on a compact metric space M, wheref: M→M is a continuous map. Let h:M→R^k be a continuous output function. Suppose that all ofthe positive orbits of f are dense and that the system is observable. We prove that any outputtrajectory of the system determines f and h and M up to a homeomorphism.If M is a compactAbelian topological group and f is an ergodic translation, then any output trajectory determinesthe system up to a translation and a group isomorphism of the group. 展开更多
关键词 A STATE space ISOMORPHISM THEOREM F0R MINIMAL DYNAMICAL SYSTEMS LIM
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Consumption Inequality in China: Theory and Evidence from the China Health and Nutrition Survey 被引量:3
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作者 Kunyuan Qiao 《Frontiers of Economics in China-Selected Publications from Chinese Universities》 2013年第1期91-112,共22页
We investigate consumption inequality in China both theoretically by constructing a theoretical model that delineates the transmission channels by which income shocks affect consumption and empirically through an Uneq... We investigate consumption inequality in China both theoretically by constructing a theoretical model that delineates the transmission channels by which income shocks affect consumption and empirically through an Unequally Spaced Dynamic Panel Data model estimation. We find that China is experiencing consumption inequality with the full partial insurance of consumption against both permanent and transitory income shocks, although the impact of both types of shock are larger than the case of the United States. The results are due to precautionary savings motives of the Chinese. We further document how income becomes more dispersed in China and show how the family background of a child affects his outcome to a large extent. Policy implications based on our findings are proposed. 展开更多
关键词 consumption inequality income shocks transmission channels Unequally spaced Dynamic Panel Data (USDPD)
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Spatial-temporal Dynamic Forecasting of EVs Charging Load Based on DCC-2D
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作者 Shurong Peng Heng Zhang +4 位作者 Yunhao Yang Bin Li Sheng Su Shijun Huang Guodong Zheng 《Chinese Journal of Electrical Engineering》 CSCD 2022年第1期53-62,共10页
The charging load of electric vehicles(EVs)has a strong spatiotemporal randomness.Predicting the dynamic spatiotemporal distribution of the charging load of EVs is of great significance for the grid to cope with the a... The charging load of electric vehicles(EVs)has a strong spatiotemporal randomness.Predicting the dynamic spatiotemporal distribution of the charging load of EVs is of great significance for the grid to cope with the access of large-scale EVs.Existing studies lack a prediction model that can accurately describe the dual dynamic changes of EVs charging the load time and space.Therefore,a spatial-temporal dynamic load forecasting model,dilated causal convolution-2D neural network(DCC-2D),is proposed.First,a hole factor is added to the time dimension of the three-dimensional convolutional convolution kernel to form a two-dimensional hole convolution layer so that the model can learn the spatial dimension information.The entire network is then formed by stacking the layers,ensuring that the network can accept long-term historical input,enabling the model to learn time dimension information.The model is simulated with the actual data of the charging pile load in a certain area and compared with the ConvLSTM model.The results prove the validity of the proposed prediction model. 展开更多
关键词 Time and space dynamic prediction dilated convolution charging load convolutional neural network
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