检索结果-内蒙古大学图书馆

67th International Astronautical Congress, IAC 2016

作者： Peng, Qin Yang, Cao Lu, Gao Zhiye, Jiang Jinliang, Bai National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics China Academy of Launch Vehicle Technology No. 1 Nan Da Hong Men Road Beijing China

Small spacecrafts have many advantages such as distribution area controllable, flexible, easy networking and co-optimal allocation of resources. The distributed collaborative networking technology can make several small spacecrafts to co-ordinate and work together as a whole. The technology has good prospects in the aerospace field and has obtained wide attention, for it can achieve communication transmission, space exploration, decision-making tasks and other functions. This paper proposes a collaborative networking solution based on small spacecraft, focusing on the research of key technologies such as networking method, communication protocols, synchronous communication and interference. This paper designed a collaborative network communication system solution, developed a prototype and verified the feasibility of the solution through simulation analysis and prototype testing. This paper also suggested the ideas and methods to improve future collaborative network communication system. Copyright © 2016 by the International Astronautical Federation (IAF). All rights reserved.

关键词： Spacecraft

来源：评论

学校读者我要写书评

暂无评论

Real-Time Path Planning based on the Lock Loss Model

Real-Time Path Planning based on the Lock Loss Model

引用

2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Luo, Xun Liu, Li Liu, Xin National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematical Beijing China China Academy of Launch Vehicle Technology Beijing China

ISBN: (纸本)9781665452366

A new method of aircraft low altitude penetration is proposed with temporal constraints that allow periods of high observability interspersed with periods of low observability. The aircraft's RCS character is simplified into the 'bow-tie' distribution, then the aircraft can dynamically adjust its yaw angle to minimize the risk from the radars. According to the modified Lock Loss model and the TWS(Track While Scan) radar work flow, and real-time evaluating model on the original path, a fast real-time path planning method is present on the situation that unexpected threats occur. An example of real-time path planning is given. © 2022 IEEE.

关键词： Locks (fasteners)

来源：评论

学校读者我要写书评

暂无评论

Measurement and Analysis of Si3N4 Particles by Infrared Spectrum 3

Measurement and Analysis of Si3N4 Particles by Infrared Spec...

引用

3rd International Computing Imaging Conference, CITA 2023

作者： Wang, Xiaoli Li, Yanan Wei, Sai Li, Xinghua Yu, Han Aerospace Research Institute of Materials & Processing Technology Beijing China Beijing University of Technology Beijing China National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing China

ISBN: (纸本)9781510671409

In this paper, the principle of Attenuated Total Reflection (ATR) is used to test and study the silicon nitride particle samples, and the influence of particle size, shape and crystal phase on its infrared spectral performance is emphatically analyzed. It is found that the larger the particle size of Si3N4 is, the more its extinction peak moves to the long wave. The smaller the particle size is, the lower the extreme value of infrared transmission in the characteristic spectrum segment is. For Si3N4 particles of the same scale, spherical like particles can obtain lower infrared transmittance, while cylindrical like ones show a wider range of infrared absorption bands. Under the same shape and similar scale, α Phase Si3N4 particles have better infrared absorption than β Phase. © 2023 SPIE.

关键词： Fourier transform infrared spectroscopy

来源：评论

学校读者我要写书评

暂无评论

Motion Prediction for Target Tracking with Bearing-only Measurement 41

Motion Prediction for Target Tracking with Bearing-only Meas...

引用

第41届中国控制会议

作者： Cuicui Jiang Yizhong Fang Qinglei Hu School of Automation Science and Electrical Engineering Beihang University National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics Beijing Institute of Space Long March Vehicle Beihang Hangzhou Innovation Institute Yuhang

ISBN: (数字)9789887581536

ISBN: (纸本)9781665482561

Target tracking with bearing-only measurement plays an important role for autonomous guidance and control ***,in some no-bearing measurement cases,the target motion should be predicted based on the available history *** this end,this paper compares two typical nonlinear Kalman filter techniques with the bearing measurement to firstly estimate the target state and ***,several Sigma points are chosen around the state by combining the unscented transform with the ***,for a long prediction time,the Sigma points are fed into the kinematic model to recursively obtain the target ***,the statistical properties are concluded from the Sigma points predictions,including the state mean and *** is shown that the covariance can provide an uncertainty region analysis for the target ***,the numerical simulation is given to validate the effectiveness of the proposed motion prediction approach.

关键词： Bearing-only Kalman Filter Unscented Transform Motion Prediction

来源：评论

学校读者我要写书评

暂无评论

Deep representation method for radar emitter signal using wavelet packets decomposition

Deep representation method for radar emitter signal using wa...

引用

IET International Radar Conference 2018, IRC 2018

作者： Cao, Yang Bai, Jin Liang Li, Hongbo Zhao, Jian Liu, Shuo Gao, Zhiyong National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics Beijing China School of Electronics and Information Engineering Harbin Institute of Technology Harbin China

Signal representation is to transform the intercepted original signal into feature parameters, which is the basis for the electronic reconnaissance system to analyse and identify a radar. The traditional method is to manually design a limited number of features with prior knowledge, which can only achieve the desired results in specific applications. Therefore, it is necessary to study signal representation methods that are more adaptable, reasonable, and effective. This study proposes a feature-level design scheme that extracts multi-level signal feature parameters to obtain deep essential feature representations, which is consistent with deep-learning frameworks. Through the decomposition through wavelet packet transform (WPT), the best sub-band tree structure of the signal can be obtained, and the depth representation of the signal can be well achieved, which can meet requirements of time-frequency analysis automatically. Here, Symlets wavelet packet decomposition (WPD) is used as an example to implement multi-layer signal feature representation. The combination of characteristic parameters at different levels can reflect the different information contained in different radar signals. The simulation results show that the method can effectively identify the modulation mode of radar signals and enhance the information mining ability from radar signals. © 2019 Institution of Engineering and technology. All rights reserved.

关键词： Radar

来源：评论

学校读者我要写书评

暂无评论

Localized Heating and Dynamics of the Solar Corona due to a Symbiosis of Waves and Reconnection

arXiv

引用

arXiv 2025年

作者： Srivastava, A.K. Mondal, Sripan Priest, Eric R. Mishra, Sudheer K. Pontin, David I. Kwon, R.Y. Yuan, Ding Murawski, K. Asai, Ayumi Varanasi221005 India Mathematics Institute St Andrews University St AndrewsKY16 9SS United Kingdom Astronomical Observatory Kyoto University Sakyo Kyoto606-8502 Japan School of Information and Physical Sciences University of Newcastle Australia Korea Astronomy and Space Science Institute Daejeon34055 Korea Republic of Shenzhen Key Laboratory of Numerical Prediction for Space Storm Institute of Space Science and Applied Technology Harbin Institute of Technology Guangdong Shenzhen China Institute of Physics University of Maria Curie-Sklodowska Pl. M. Curie-Sklodowskiej 5 Lublin20-031 Poland

The Sun’s outer atmosphere, the corona, is maintained at mega-Kelvin temperatures and fills the heliosphere with a supersonic outflowing wind. The dissipation of magnetic waves and direct electric currents are likely to be the most significant processes for heating the corona, but a lively debate exists on their relative roles. Here, we suggest that the two are often intrinsically linked, since magnetic waves may trigger current dissipation, and impulsive reconnection can launch magnetic waves. We present a study of the first of these processes by using a 2D physics-based numerical simulation using the Adaptive Mesh Refined (AMR) Versatile Advection Code (VAC). Magnetic waves such as fast magnetoacoustic waves are often observed to propagate in the large-scale corona and interact with local magnetic structures. The present numerical simulations show how the propagation of magnetic disturbances towards a null point or separator can lead to the accumulation of the electric currents. Lorentz forces can laterally push and vertically stretch the magnetic fields, forming a current sheet with a strong magnetic-field gradient. The magnetic field lines then break and reconnect, and so contribute towards coronal heating. numerical results are presented that support these ideas and support the concept of a symbiosis between waves and reconnection in heating the solar corona. Copyright © 2025, The Authors. All rights reserved.

关键词： Lorentz force

来源：评论

学校读者我要写书评

暂无评论

Periodic Structures and Its Interaction to EM Wave Spectrum, Ideas From X-Ray to MW Wave

Periodic Structures and Its Interaction to EM Wave Spectrum,...

引用

2022 International Applied Computational Electromagnetics Society Symposium, ACES-China 2022

作者： Tang, Yunhui Gao, Lu Wang, Ruzhi Zhang, Shengjun Song, Hang Zhang, Yuning Ai, Xia Xie, Lei Jiao, Luting Zhang, Xiaoling He, Jing Liu, Jiaqi Beijing University of Technology Beijing China National Key Laboratory of Science & Technology on Test Physics and Numerical Mathematics Beijing China Beijing Institute of Space Long March Vehicle Beijing China

ISBN: (纸本)9781665452366

X-ray is an important tool for characterizing materials, which is based on the idea that all crystals are composed of atoms or molecules stacking in a particular type, basically expressing as unit cell, diffracting the incident ray with a proper type. In analogue, the periodic structures which are mostly constructed artificially show special desired properties, such as the properties of grating, frequency selective surfaces, metamaterials and metasurface. In this paper, A study was done on the insight of the relation of wave interaction with periodic structures based on X-ray diffraction and control of electromagnetic waves. © 2022 IEEE.

关键词： Periodic structures

来源：评论

学校读者我要写书评

暂无评论

Automatic MHT Method Based on Target Characteristics Applied in the Small Space Targets

Automatic MHT Method Based on Target Characteristics Applied...

引用

2018 3rd International Conference on Design, Mechanical and Material Engineering (D2ME 2018)

作者： Qian ZHAO Zhenhong NIU Lian XUE Xin LIU Jianhua LI Zhifeng LI National Key Laboratory of Science and Technology on Test Physics & Numerical Mathematics

The Multi-Hypothesis Tracking(MHT) method is one of the most promising approaches to realize automatic tracking of small and dim targets in complex space ***,the number of hypotheses generated by this algorithm has an exponentially increasing relationship with the number of trajectories,measurement data,and the number of image *** the paper,the automatic detection and tracking method of judging the confidence coefficient of the trajectory obtained by the MHT which is based on the characteristics of dim targets,has been realized in the IRST *** performance of this method is greatly improved.

关键词： image Automatic MHT Method Based on Target Characteristics Applied in the Small Space Targets MHT Target

来源：评论

学校读者我要写书评

暂无评论

Station Layout Optimization Genetic Algorithm for Four Stations TDOA Location

Station Layout Optimization Genetic Algorithm for Four Stati...

引用

第二届人工智能、网络与信息技术国际研讨会

作者： Ruiqi Sun Zhonghang He Lu Gao Jinliang Bai National Key Laboratory of Science and Technology on Test Physics and Numerical Mathematics

Station layout has a direct impact on localization precision for four-station TDOA(time difference of arrival) location system. In order to optimize the overall location precision of targets in certain area, genetic algorithm for station layout optimization is presented. GDOP is regarded as the measurement rule of location precision. Then the multi-object programming mathematical model of station layout optimization is built. The optimal solution is searched by genetic algorithm. Consequently, the optimal layout of station is obtained. The simulation provides the GDOP distribution of two station layouts. One is the initial station layout, and the other is the optimal station layout. The simulation results show that for the optimal station layout, the effect of improving the location precision is obvious, and also indicate the validity of genetic algorithm.

关键词： Station Layout Optimization Genetic Algorithm for Four Stations TDOA Location

来源：评论

学校读者我要写书评

暂无评论

numerical simulation based on two-directional freeze and thaw algorithm for thermal diffusion model

引用

Applied mathematics and Mechanics(English Edition) 2016年第11期37卷 1467-1478页

作者： Junqiang GAO Zhenghui XIE Aiwen WANG Zhendong LUO State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric PhysicsChinese Academy of Sciences School of Mathematics and Physics North China Electric Power University School of Applied Science Beijing Information and Science Technology University

Freeze-thaw processes significantly modulate hydraulic and thermal char- acteristics of soil. The changes in the frost and thaw fronts （FTFs） affect the water and energy cycles between the land surface and the atmosphere. Thus, the frozen soil com- prising permafrost and seasonally frozen soil has important effects on the land surface hydrology in cold regions. In this study, a two-directional freeze and thaw algorithm is incorporated into a thermal diffusion equation for simulating FTFs. A local adaptive variable-grid method is used to discretize the model. Sensitivity tests demonstrate that the method is stable and FTFs can be tracked continuously. The FTFs and soil tempera- ture at the Qinghai-Tibet Plateau D66 site are simulated hourly from September 1, 1997 to September 22, 1998. The results show that the incorporated model performs much better in the soil temperature simulation than the original thermal diffusion equation, showing potential applications of the method in land-surface process modeling.

关键词： freeze and thaw algorithm frost and thaw front (FTF) sensitivity test,thermal diffusion equation

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：