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2021 5th International Conference on Electrical, Automation and Mechanical Engineering, EAME 2021

作者： Li, Zhanxin Cao, Zizhen Duan, Wenjie Du, Yikang Liu, Haiteng Tianjin Institute of Aerospace Mechanical and Electrical Equipment Tianjin China Tianjin Key Laboratory of Microgravity Environment Simulation Technology Tianjin China Beijing Institute of Control Engineering Beijing China Science and Technology on Space Intelligent Control Laboratory Beijing China

The most important interfering torque of a three-axis air-bearing simulator is the displacement of the center of mass in the gravity field caused by structural elasticity. In order to characterize the torque, a mathematical model of the interference moment was established. Based on the model, it is suggested that the vertical stiffness and horizontal stiffness of the structure should be equal as far as possible during the structural design, and the elastic unbalance moment can be compensated by the vertical offset of the center of mass of the air floating platform relative to the rotation center after the initial attitude leveling. ABAQUS was used to build a simulation model of the air floating platform, and the changes of the structure's centroid before and after the gravitational field was applied were extracted by software to simulate the centroid deviation caused by the elastic deformation of the structure, which was used as the characterization to conduct discrete optimization of the structure. The optimal structural parameters were obtained. Then the disturbance torque curve and the corresponding initial centroid offset after initial centroid compensation were calculated by mathematical model. The results are of positive guiding significance to the design of three-axis air-bearing simulator. © 2021 Institute of Physics Publishing. All rights reserved.

关键词： Torque

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Expanding carbon neutrality strategies:Incorporating out-ofboundary emissions in city-level frameworks

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Environmental science and Ecotechnology 2024年第4期20卷 145-153页

作者： Zhe Zhang Mingyu Li Li Zhang Yunfeng Zhou Shuying Zhu Chen Lv Yixuan Zheng Bofeng Cai Jinnan Wang Center for Carbon Neutrality Chinese Academy of Environmental PlanningBeijing100043China School of Environment Tsinghua UniversityBeijing100084China Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System ScienceTsinghua UniversityBeijing100084China R&D and International Cooperation Office Chinese Academy of Environmental PlanningBeijing100043China School of Economics and Management Beijing University of Chemical TechnologyBeijing100029China Center of Air Quality Simulation and System Analysis Chinese Academy of Environmental PlanningBeijing100043China

Cities are increasingly vital in global carbon mitigation efforts,yet few have specifically tailored carbon neutrality ***,out-of-boundary indirect greenhouse gas(GHG)emissions,aside from those related to electricity and heat imports,are often overlooked in existing pathways,despite their significance in comprehensive carbon mitigation *** this gap,here we introduce an integrated analysis framework focusing on both production and consumption-related GHG *** to Wuyishan,a service-oriented city in Southern China,this framework provides a holistic view of a city's carbon neutrality pathway,from a full-scope GHG emission *** findings reveal the equal importance of carbon reduction within and outside the city's boundaries,with out-of-boundary emissions accounting for 42%of Wuyishan's present total GHG *** insight highlights the necessity of including these external factors in GHG accounting and mitigation strategy *** framework serves as a practical tool for cities,particularly in developing countries,to craft effective carbon neutrality roadmaps that encompass the full spectrum of GHG emissions.

关键词： Greenhouse gas emissions Full-scope emission accounting Carbon neutrality pathway City-level

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A Multi-Modal Multi-Objective Evolutionary Algorithm Based on Dual Decomposition and Subset Selection

SSRN

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SSRN 2023年

作者： Xiong, Minghui Xiong, Wei Liu, Zheng Liu, Yali Han, Chi Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing101416 China

Multi-modal multi-objective problems (MMOPs) arise frequently in real world applications, in which multiple Pareto-optimal solution sets (PSs) correspond to the same point on the Pareto front (PF). Diversity preservation is a crucial issue in multi-modal multi-objective evolutionary algorithms (MMEAs), which aims at evolving the population toward the PF and equivalent PSs with a uniform distribution and good spread. In spite of many diversity preservation approaches in MMEAs, most of them guarantee the diversity in decision space with a degraded performance in objective space. To address the above issues, this article proposes a MMEA based on dual decomposition and subset selection, which employes the weight vectors and grids to decompose both the objective and decision spaces. On the basis of dual decomposition, the mating selection are adaptively performed based on estimated optimization stages of current subproblem. Moreover, a subset with good diversity in both the objective and decision spaces are selected from the promising solutions ever collected during the evolution process. Experimental results on 22 benchmark problems demonstrate our advantages to maintain a more balanced diversity in both objective and decision spaces. © 2023, The Authors. All rights reserved.

关键词： Multiobjective optimization

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The solar wind plasma upstream of Mars observed by Tianwen-1:Comparison with Mars Express and MAVEN

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science China Earth sciences 2022年第4期65卷 759-768页

作者： Kai FAN Limei YAN Yong WEI Aibing ZHANG Linggao KONG Markus FRÄNZ Fei HE Lihui CHAI Chongjing YUAN Yuqi WANG Jun ZHONG Zhaojin RONG Zhonghua YAO Yongxin PAN Jun CUI Jiansen HE Wenya LI Binbin TANG Chi WANG Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of SciencesBeijing 100029China College of Earth and Planetary Sciences University of Chinese Academy of SciencesBeijing 100049China National Space Science Center Chinese Academy of SciencesBeijing 100190China Beijing Key Laboratory of Space Environment Exploration Beijing 100190China Key Laboratory of Science and Technology on Space Environment Situational Awareness Chinese Academy of SciencesBeijing 100190China Max-Planck-Institute for Solar System Research Goettingen 37077Germany State Key Laboratory of Space Weather Chinese Academy of SciencesBeijing 100190China School of Atmospheric Sciences Sun Yat-Sen UniversityZhuhai 519082China Institute of Space Physics and Applied Technology Peking UniversityBeijing 100871China

On the great journey to Mars,China’s first planetary exploration mission,the Tianwen-1 came within 26 million kilometers of Mars from 31 October 2020 to 25 January 2021 and was getting closer to its destination,the red planet,in search of answers to the cataclysmic climate change that occurred in Martian *** the escape of the Martian atmosphere and the loss of surface water were firmly influenced by solar ***-1 provided a unique chance to depict the solar wind streams between Earth and Mars during the minimum of Solar Cycle *** the three-month cruise phase of Tianwen-1,the solar wind flows were successively observed at Earth,Tianwen-1,and *** the field of view correction and noise reduction,the solar wind velocity and density measured by Tianwen-1 show good agreement with those at Earth and *** results indicate that the performance of the ion analyzer onboard the Tianwen-1 orbiter is reliable and *** is worth looking forward to the joint observations of ion escape with other Mars probes in the following Martian years.

关键词： Tianwen-1 Mars Plasma moment Solar wind

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A Robust Path Following Controller for a Small Unmanned Aerial Vehicle with Constrained Parameters Optimized

A Robust Path Following Controller for a Small Unmanned Aeri...

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International Conference on Information science and Control Engineering (ICISCE)

作者： Yang Chen Chaolei Wang School of Mechanical and Electrical Engineering Longyan University Longyan China Science and Technology on Special System Simulation Laboratory Beijing Simulation Center Beijing China

ISBN: (纸本)9781509025367

This paper proposes a nonlinear controller that allows the unmanned air vehicle (UAV) to follow a predefined path. The controller only needs the information of the inertial speed of the UAV and the distance between the vehicle and the desired path. In order to improve the performance of the controller, a parameter of the controller is optimized by using the concept of model predictive control (MPC). Lyapunov stability arguments are used to demonstrate that the path following error will be regulated to zero, even in the presence of wind disturbances. simulation results in Matlab are given to show the effectiveness of the controller. The simulation results show that the proposed path following controller with parameter optimized by MPC (PLC_MPC) which takes the advantages of the predictive ability of the MPC and the simple structure of the normal path following controller (PLC) has better path following performance than that by using the PLC method.

关键词： Unmanned aerial vehicles Mathematical model Optimization Stability analysis Trajectory Lyapunov methods

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Olivine-norite rock detected by the lunar rover Yutu-2 likely crystallized from the SPA-impact melt pool

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National science Review 2020年第5期7卷 913-920页

作者： Honglei Lin Zhiping He Wei Yang Yangting Lin Rui Xu Chi Zhang Meng-Hua Zhu Rui Chang Jinhai Zhang Chunlai Li Hongyu Lin Yang Liu Sheng Gou Yong Wei Sen Hu Changbin Xue Jianfeng Yang Jie Zhong Xiaohui Fu Weixing Wan Yongliao Zou Key Laboratory of Earth and Planetary Physics Institute of Geology and Geophysics Chinese Academy of Sciences Key Laboratory of Space Active Opto-Electronics Technology Shanghai Institute of Technical Physics Chinese Academy of Sciences State Key Laboratory of Lunar and Planetary Sciences Macau University of Science and Technology Beijing Institute of Space Mechanics and Electricity State Key Laboratory of Space Weather National Space Science CenterChinese Academy of Sciences State Key Laboratory of Remote Sensing Science Institute of Remote Sensing and Digital Earth Chinese Academy of Sciences Key Laboratory of Electronics and Information Technology for Space System National Space Science Center Chinese Academy of Sciences Xi'an Institute of Optics and Precision Mechanics Chinese Academy of Sciences Institute of Optics and Electronics Chinese Academy of Sciences Shandong Provincial Key Laboratory of Optical Astronomy and Solar-Terrestrial Environment Institute of Space SciencesShandong University

Chang’E-4 landed in the South Pole-Aitken (SPA) basin,providing a unique chance to probe the composition of the lunar *** landing site is located on ejecta strips in Von Karman crater that possibly originate from the neighboring Finsen crater.A surface rock and the lunar regolith at 10 sites along the rover Yutu-2 track were measured by the onboard Visible and Near-Infrared Imaging Spectrometer in the first three lunar days of mission *** situ spectra of the regolith have peak band positions at 1and 2μm,similar to the spectral data of Finsen ejecta from the Moon Mineralogy Mapper,which confirms that the regolith’s composition of the landing area is mostly similar to that of Finsen *** rock spectrum shows similar band peak positions,but stronger absorptions,suggesting relatively fresh *** rock may consist of 38.1±5.4%low-Ca pyroxene,13.9±5.1%olivine and 48.0±3.1%plagioclase,referred to as *** plagioclase-abundant and olivine-poor modal composition of the rock is inconsistent with the origin of the mantle,but representative of the lunar lower ***,the rock crystallized from the impact-derived melt pool formed by the SPA-impact event via mixing the lunar crust and mantle *** scenario is consistent with fast-cooling thermal conditions of a shallow melt pool,indicated by the fine to medium-sized texture (<3 mm) of the rock and the SPA-impact melting model[Icarus2012;220:730-43].

关键词： impact basin lunar interior composition visible and near-infrared spectra lunar rover Yutu-2 Chang’E-4 mission

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Prediction of Direct Normal Irradiation Based on CNN-LSTM Model 20

Prediction of Direct Normal Irradiation Based on CNN-LSTM Mo...

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5th International Conference on Multimedia systems and Signal Processing, ICMSSP 2020

作者： Zhang, Chengying Yan, Zhen Ma, Chao Xu, Xiaoli Key Laboratory of Space Utilization Technology and Engineering Center for Space Utilization Chinese Academy of Sciences Beijing China Beijing Key Laboratory of Measurement and Control of Mechanical and Electrical System Beijing Information Science and Technology University Beijing China

ISBN: (纸本)9781450377485

Due to the intermittency and instability of power output of solar power stations (SPS), the safety and stationarity of the electric grid are facing considerable challenges. So, it is essential to predict the power output of SPS accurately. To date, as the most important meteorological factor determining the power output of SPS, the prediction of direct normal irradiation (DNI) has always been a hotspot, however at the same time a challenging problem. In recent years, with the improvement of hardware performance, deep learning methods have witnessed rapid development in the field of forecasting of renewable energies. In this paper, a hybrid method combining convolutional neural network (CNN) and longshort term memory (LSTM) neural network is proposed, the former can be effectively used for extraction of spatial feature, while the latter is used for extraction of temporal feature. As a case study, the proposed method is used for prediction of DNI of four typical days, i.e. spring equinox, summer solstice, autumn equinox, and winter solstice, based on the meteorological conditions of Zhangbei. The results show that deep learning methods can be effectively used for prediction of DNI, however, the proposed method in this paper achieves higher prediction accuracy than that of the compared methods. © 2020 ACM.

关键词： Convolutional neural networks

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Target Identity Fusion Method Based on Improved DS Evidence Theory

Target Identity Fusion Method Based on Improved DS Evidence ...

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Electronic Information Engineering and Computer technology (EIECT), International Conference on

作者： Yi Wang Desheng Liu Yang Yang Jiatong Liu Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing China Space Engineering University Beijing China

Target data detected by multi-sensors often differ from each other due to different sensor performances, resulting in uncertainty of target identity information. Traditional Dempster-Shafer (DS) evidence theory may achieve counter-intuitive outcomes facing evidence conflicts caused by the uncertainty. Aiming for this, a novel target identity fusion method based on improved DS evidence theory is proposed in this paper. Specifically, the method considers the correlation between evidences and the importance of evidences integrally. First, an improved conflict measurement method based on Pearson correlation coefficient matrix is devised to measure the evidence credibility. Next the information volume of evidences is measured by Deng-entropy to indicate the evidence uncertainty. Then the credibility and uncertainty are weighted and combined to modify the basic probability assignment (BPA) of evidences. Ultimately, the modified evidences are fused by Dempster’s combination rule to acquire the final results. Through three numerical analysis examples, this paper demonstrates the superiority of the proposed method over typical previous approaches, which can effectively process evidence conflicts in multi-sensors information fusion.

关键词：

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Field assessment of straw pellet combustion in improved heating stoves in rural Northeast China

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Journal of Environmental sciences 2023年第5期127卷 295-307页

作者： Yafei Liu Zhimin Li Emily Floess You Zhang Nicholas Lam Sylvester K.Mawusi Prabin Shrestha Xinghua Li Chunyu Xue Guangqing Liu Biomass Energy and Environmental Engineering Research Center College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China State Key Laboratory of Water Environment Simulation School of EnvironmentBeijing Normal UniversityBeijing 100875China Department of Civil Constructionand Environmental EngineeringNorth Carolina State UniversityRaleighNC 27695-7103USA Schatz Energy Research Center Humboldt State UniversityArcataCA 95521USA School of Space and Environment Beihang UniversityBeijing 100191China

Straw pellets are widely promoted and expected to be a cleaner alternative fuel to unprocessed crop residues and rawcoal in rural ***,the effectiveness of these dissemination programs is not well *** this field study,emission characteristics of burning strawpellets,rawcoal,and unprocessed corn cobs in heating stoveswere investigated in a pilot village in Northeast *** measurements covering the whole combustion cycle(ignition,flaming,and smoldering phases)shows the promotion of improved heating stoves and straw pellets could reduce pollutant emissions(e.g.,SO_(2) and CO),but increase NO_(X) and PM_(2.5) emissions compared to the initial stove-fuel use pattern in the studied *** is a significant variance in emission characteristics between different combustion *** normalized emission concentrations of the different stove-fuel combinations were higher than the limits in the Chinese national standard for heating stoves,indicating that the standard is not met for real-world *** consumption was lower than official *** surveys were conducted to identify the barriers to fuel and stove access associated with existing promotion strategies,management,and *** pilot program was of the typical“subsidy-and-policy-dependence”pattern and was unlikely to be implemented on a large *** innovation,operational optimization,and proper policies considering the local socioeconomic factors are needed to sustain the promotion of biomass straw pellets and stoves.

关键词： Northeast China Straw pellet Improved heating stove Emission factors

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Cooperative Caching Strategy Based on Two-Layer Caching Model for Remote Sensing Satellite Networks

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Computers, Materials & Continua 2023年第5期75卷 3903-3922页

作者： Rui Xu Xiaoqiang Di Hao Luo Hui Qi Xiongwen He Wenping Lei School of Computer Science and Technology Changchun University of Science and TechnologyChangchun130022China School of Information Engineering Henan Institute of Science and TechnologyXinxiang453003China Jilin Province Key Laboratory of Network and Information Security Changchun University of Science and TechnologyChangchun130022China Information Center Changchun University of Science and TechnologyChangchun130022China Beijing Institute of Spacecraft System Engineering Beijing100094China Beijing Institute of Space Mechanic and Electricity Beijing100094China

In Information Centric Networking(ICN)where content is the object of exchange,in-network caching is a unique functional feature with the ability to handle data storage and distribution in remote sensing satellite *** up cache space at any node enables users to access data nearby,thus relieving the processing pressure on the ***,the existing caching strategies still suffer from the lack of global planning of cache contents and low utilization of cache resources due to the lack of fine-grained division of cache *** address the issues mentioned,a cooperative caching strategy(CSTL)for remote sensing satellite networks based on a two-layer caching model is *** two-layer caching model is constructed by setting up separate cache spaces in the satellite network and the ground *** caching of popular contents in the region at the ground station to reduce the access delay of users.A content classification method based on hierarchical division is proposed in the satellite network,and differential probabilistic caching is employed for different levels of *** cached content is also dynamically adjusted by analyzing the subsequent changes in the popularity of the cached *** the two-layer caching model,ground stations and satellite networks collaboratively cache to achieve global planning of cache contents,rationalize the utilization of cache resources,and reduce the propagation delay of remote sensing *** results show that the CSTL strategy not only has a high cache hit ratio compared with other caching strategies but also effectively reduces user request delay and server load,which satisfies the timeliness requirement of remote sensing data transmission.

关键词： Information centric networking caching strategy two-layer caching model hierarchical division

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