检索结果-内蒙古大学图书馆

作者： Minghui Xiong Wei Xiong Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing

For the satellite constellation design problem, the computational complexity of regional coverage performance evaluation has posed great difficulty to classical Pareto dominance-based algorithms discovering the entire Pareto front of the problem, while the decision makers are often interested in a limited part of it. In this paper, a preference-based manyobjective evolutionary algorithm, HMOEA-T, is utilized to solve this problem. The optimization includes two steps. The first step describes the preference information of decision maker by target region, while the second step focuses the search process on the preferred region and maintaining well convergence and diversity within the region. A visualization method is applied to intuitively analysis the performance of different methods handling the problem. Experimental results have shown the advantage of integrating preference information into the optimization process, and the comparative study with other state-of-the-art preferencebased methods(T-MOEA/D and T-NSGA-III) indicate that the proposed method can achieve competitive and better performance.

关键词： evolutoinary algorithm preference articulation constellation design many-objective optimization

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Multistage Synchronous Secure Communication Method 1

Multistage Synchronous Secure Communication Method

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1st International Conference on Advanced Algorithms and Control Engineering, ICAACE 2018

作者： Sun, Wei He, Jun Quan, Lei Science and Technology on Complex Electronic System Simulation Labratory University of Aerospace Engineering Beijing101416 China Naval Academy of Armament China Based on Time-delayed Hyperchaotic System Beijing100161 China

To solve the security of data transmission in network, a secure communication method based on time-delayed hyperchaotic synchronization is presented. By selecting the typical hyperchaotic system, the communication system synchronization scheme is designed to realize the recovery of the encrypted signal, and the security performance of the method is analyzed by simulation. The simulation results show that the synchronization method has the characteristics of high security and is easy to implement. © Published under licence by IOP Publishing Ltd.

关键词： Secure communication

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Dual-Polarized Wideband Wide-Beam Millimeter-Wave Magneto-Electric Dipole Antenna

Dual-Polarized Wideband Wide-Beam Millimeter-Wave Magneto-El...

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2023 Cross Strait Radio science and Wireless technology Conference, CSRSWTC 2023

作者： Gou, Linglong Ma, Jing Shi, Bin Zhu, Zhongbo Peng, Lin Guilin University of Electronic Technology Key Laboratory of Microwave and Optical Wave Application Technology Guangxi Guilin541004 China Beijing Simulation Center The Science and Technology on Special System Simulation Laboratory Beijing100854 China The National Key Laboratory of Science and Technology on Space Microwave Xi'an710100 China

ISBN: (纸本)9798350358971

In this manuscript, a dual-polarized wideband wide beamwidth magneto-electric (ME) dipole antenna for millimeter-wave mobile communication is proposed. As can be seen from the simulation results, this design exhibits excellent performance. Owing to the mutual resonances of the magnetic dipole and the electric dipole, large bandwidths of 64.8% and 59% (18.4 GHz-33 GHz and 17.29 GHz-33.9 GHz) are obtained for the two polarizations, respectively. The isolation between the two ports is greater than 25 dB. By loading metal vias, the antenna's beamwidth is widened to more than 100° through the whole operating band. The antenna size is 5mm×5 mm ×1.72 mm, and this compact structure is quite suitable for using in beam scanning antennas. © 2023 IEEE.

关键词： dual-polarization millimeter-wave (mm-wave) wideband

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Research on the Scattering Characteristics of Motion Modulated Ultra-long Chaff 4

Research on the Scattering Characteristics of Motion Modulat...

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4th International Applied Computational Electromagnetics Society Symposium in China, ACES-China 2021

作者： Lin, Gan Jianbing, Li Xin, Liu Xuesong, Wang College of Electronic Science and Technology National University of Defense Technology State Key Laboratory of Complex Electromagnetic Effects on Electronics and Information System Changsha China

ISBN: (纸本)9781733509619

In order to develop a new kind low-dimensional and efficient chaff interference mode, a discontinuous super-long chaff made of S-type glass fiber is proposed. In this paper, its kinematics and scattering characteristics in the thin atmosphere are emphatically studied. simulation results show that long chaffs have stronger shape-maintaining ability and better interference effect than the traditional dipole chaffs under different polarization conditions. © 2021 Applied Computational Electromagnetics Society (ACES).

关键词： Finite element method

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Depth estimation using an improved stereo network

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Frontiers of Information technology & electronic Engineering 2022年第5期23卷 777-789页

作者： Wanpeng XU Ling ZOU Lingda WU Yue QI Zhaoyong QIAN Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering UniversityBeijing 101416China Peng Cheng Laboratory Shenzhen 518055China Digital Media School Beijing Film AcademyBeijing 100088China

Self-supervised depth estimation approaches present excellent results that are comparable to those of the fully supervised approaches,by employing view synthesis between the target and reference images in the training ***,which serves as a backbone network,has some structural deficiencies when applied to downstream fields,because its original purpose was to cope with classification *** low-texture area also deteriorates the *** address these problems,we propose a set of improvements that lead to superior ***,we boost the information flow in the network and improve the ability to learn spatial structures by improving the network ***,we use a binary mask to remove the pixels in low-texture areas between the target and reference images to more accurately reconstruct the ***,we input the target and reference images randomly to expand the dataset and pre-train it on ImageNet,so that the model obtains a favorable general feature *** demonstrate state-of-the-art performance on an Eigen split of the KITTI driving dataset using stereo pairs.

关键词： Monocular depth estimation Self-supervised Image reconstruction

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Modelling and Analyses of the Range Gate Pull-off (RGPO) Effect on Radar Tracking

Modelling and Analyses of the Range Gate Pull-off (RGPO) Eff...

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2024 Photonics and Electromagnetics Research Symposium, PIERS 2024

作者： Wang, Yanfeng Wu, Qihua Zhao, Tiehua Liu, Xiaobin Zhao, Feng Xiao, Shunping National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics and Information System College of Electronic Science and Technology China

ISBN: (纸本)9798350375909

Range gate pull-off (RGPO) Jamming disrupts tracking capability of radar system by strategically increasing the latency of radar signal. Hence this kind of active deception jamming is widely adopted. The quantitative assessment and evaluation of RGPO Jamming effects on radar systems is of great significance for enhancing radar anti-jamming capabilities. However, difficulties exist in establishing a mathematical model for analyzing the jamming effects through theoretical analyses. Both the complexity of different radar systems and randomness of radar tracking processes add to this challenge. These factors result in substantial workload to analyze jamming effects. Considering these challenges, a modelling method for RGPO effects on radar based on digital simulation results is introduced in this study. Firstly, the radar range tracking model was established. Through the qualitative analyses of the process of RGPO jamming effect and the principle of affecting the tracking loop, it was found that the rate of a successful pulling off would show a precipitous drop after the pulling speed exceeds a certain threshold. This conclusion was verified in the simulation results of the RGPO effect simulation system. On this basis, to build the relationship between the maximum pull-off speed and the Jamming-to-Signal Ratio (JSR), a modelling method based on spline interpolation and least squares fitting was proposed in this study. The work contributes to a deeper understanding of the impact of RGPO Jamming on radar tracking, and provides valuable insights for bolstering radar countermeasures. © 2024 IEEE.

关键词： Radar countermeasures

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Knowledge-driven material design platform based on the whole-process simulation and modeling

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International Journal of Modeling, simulation, and Scientific Computing 2022年第2期13卷 1-15页

作者： Gongzhuang Peng Tie Li Xiang Zhai Wenzheng Liu Heming Zhang National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing Beijing 100083 P.R.China Shanghai Electro-Mechanical Engineering Institute Shanghai 201109 P.R.China State Key Laboratory of Intelligent Manufacturing System Technology Beijing Institute of Electronic System Engineering Beijing 100854 P.R.China Beijing Complex Product Advanced Manufacturing Engineering Research Center Beijing Simulation Center Beijing 100854P.R.China Science and Technology on Space System Simulation Laboratory Beijing Simulation Center Beijing 100854P.R.China National CIMS Engineering Research Center Tsinghua University Beijing 100084P.R.China

In order to realize the agility,collaboration and visualization of alloy material devel-opment process,a product development platform based on simulation and modeling technologies is established in this *** this platform,the whole-process simulation module builds multi-level simulation models based on metallurgical mechanisms from the production line level,the thermo-mechanical coupling field level and the microstructure evolution *** design knowledge management module represents the multi-source heterogeneous material design knowledge through ontology model,including customers’requirement knowledge,material component knowledge,process design knowledge and quality inspection knowledge,and utilizes the case-based reasoning approach to reuse the *** data-driven modeling module applies machine learning algorithms to mine the relationships between product mechanical properties,material components,and process parameters from historical samples,and utilizes multi-objective optimiza-tion algorithms to find the optimal combination of process *** of the developed platform in actual steel mills shows that the proposed method helps to improve the efficiency of product design process.

关键词： Product development knowledge-based engineering multi-scale simulation performance prediction model

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A modified PSO-BP algorithm in hydraulic system fault diagnosis application

A modified PSO-BP algorithm in hydraulic system fault diagno...

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2012 International Applied Mechanics, Mechatronics Automation Symposium, IAMMAS 2012

作者： Dong, Zengshou Zhang, Xiaoyu Zeng, Jianchao Dept. of Electronic Information Engineering Taiyuan University of Science and Technology Taiyuan China The System Simulation and Computer Application Research Laboratory Taiyuan University of Science and Technology Taiyuan China

ISBN: (纸本)9783037854266

BP neural network for failure pattern recognition has been used in hydraulic system fault ***, its convergence rate is relatively small and always trapped at the local minima. So a new modified PSO-BP hydraulic system fault diagnosis method was proposed,which combined the respective advantages of particle swarm algorithm and BP algorithm. Firstly, the inertia weight and learning factor of the standard particle swarm algorithm was improved, then BP neural network's weights and thresholds were optimized by modified PSO algorithm. BP network performance was ameliorated. The simulation results showed that this method improved the convergence rate of the BP network, and it could reduce the diagnostic errors. © (2012) Trans Tech Publications, Switzerland.

关键词： Failure analysis

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A Light Gradient Boosting Machine Based Effectiveness Prediction Method of Space Reconnaissance system

A Light Gradient Boosting Machine Based Effectiveness Predic...

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IEEE Advanced Information technology, electronic and Automation Control Conference (IAEAC)

作者： Jiahuan Liu Ping Jian Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing China

To address the problem of effectiveness evaluation of space reconnaissance systems with limited data sets, vast array of indexes and inadequate model interpretability, an interpretable effectiveness prediction method based on Light Gradient Boosting Machine(LightGBM) and the Shapley Additive exPlanations(SHAP) is proposed. The thorough evaluation process is given and the index system of space reconnaissance systems is built. Then LightGBM is used to establish a nonlinear mapping the model between the indexes and the effectiveness. Additionally, the model’s hyperparameters are adjusted using Bayesian optimization to improve accuracy and lessen computational load. Furthermore, the feasibility of the proposed method is validated by modeling and evaluating the performance of the space reconnaissance system under a particular operational scenario. The experimental results show that compared with other mainstream machine learning methods, the proposed method has higher prediction accuracy and can efficiently extract the potential characteristics of the space reconnaissance system.

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Research on scattering characteristics of antenna array 4

Research on scattering characteristics of antenna array

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4th International Applied Computational Electromagnetics Society Symposium in China, ACES-China 2021

作者： Chen, Ao Zong, Xianzheng Nie, Zaiping Liu, Fan Wang, Youcheng Jiang, Peng School of Electronic Science and Engineering University of Electronic Science and Technology of China Chengdu China Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory Beijing Electro-Mechanical Engineering Institute Beijing China

ISBN: (纸本)9781733509619

A new RCS reduction method for the antenna array is proposed. Previous works have shown that the radiation pattern function of an antenna array is equal to the array element radiation pattern function multiplying the radiation array factor. Similarly, scattering factor is used to express an important parameter for analyzing the scattering characteristics of antenna arrays. The expression equation of the scattering factor of several conventional arrays can be derived directly, and then the maximum scattering direction of the antenna array can be obtained. In order to prove the validation of the scattering factor, several arrays are simulated by integral equation method, and finally proposed the condition of non-scattering-grating-lobe. © 2021 Applied Computational Electromagnetics Society (ACES).

关键词： Antenna arrays

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