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2018 International Conference on Computational, Modeling, simulation and Mathematical Statistics(CMSMS 2018)

作者： Ying ZHANG Hui-jie DU Yu ZHANG Yi-yuan MA Hui-yang QU Science and Technology on Special System Simulation Laboratory Beijing Simulation Center National Key Laboratory of Intelligent Manufacture System Technology for Complicated Products

The star sensor simulation system is used to test the star sensor performance on the ground, which is designed for star identification and spacecraft attitude determination of the spacecraft. The computer star scene based on the astronomical star chat is generated for hardware-in-the-loop simulation of the star sensor simulation system using OpenGL. The results of star scene generation are shown in this paper and applied in the real time star sensor simulation.

关键词： Star scene Modeling simulation Astronomical chat

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Coral growth over the past 550 years in the central South China Sea linked to monsoon- and seabird-induced nutrient stress

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Palaeogeography, Palaeoclimatology, Palaeoecology 2023年 617卷

作者： Yi Liu Shichen Tao Ruoyu Sun Chen-Feng You Tzu-Hao Wang Thomas Felis Wang Zheng Shaobo Sun Xiaodong Liu Qi Shi Jianxin Zhao Kefu Yu Institute of Surface-Earth System Science School of Earth System Science Tianjin University Tianjin China Coral Reef Research Center of China Guangxi Laboratory on the Study of Coral Reefs in the South China Sea School of Marine Sciences Guangxi University Nanning China South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou China Department of Earth Sciences National Cheng Kung University Tainan Taiwan MARUM - Center for Marine Environmental Sciences University of Bremen Bremen Germany School of Earth and Space Sciences University of Science and Technology of China Hefei China Radiogenic Isotope Facility School of Earth and Environmental Sciences University of Queensland St Lucia Queensland Australia

Nutrient enrichment is a widely recognized threat to coastal coral reefs. Yet its impact on open ocean reefs is largely unknown due to the lack of long-term observations at remote sites and the entanglement of various environmental factors affecting coral growth. Here we determined growth rates and the carbonate chemistry of calcifying fluid (CF) of massive corals over the last 550 years at a remote South China Sea reef ecosystem. We show that large growth variations cannot be fully explained by changes in seawater pH or temperature due to the antiphase relationship between growth rate and pH cf as well as small sea surface temperature variations before the 1960s. Instead, coral growth rate decreases proportionally with past seabird populations over the past centuries. We suggest that excess nutrient loads through monsoon pumping and seabird migration played an important role in controlling coral growth at this remote reef ecosystem. Specifically, episodic eutrophication as indicated by a ∼ 3 per mil increase in coral δ 13 C has depressed coral growth by ∼30% during 15th to 18th centuries, which is comparable to the modern decline. Thus, accurate projections of future coral growth for remote reefs under ongoing human activities and climate change needs to take into account the history of past nutrient inputs into these ecosystems under pre-anthropogenic conditions, which has been overlooked previously due to a lack of historical observations.

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Corrigendum to “How urban land-use intensity affected CO 2 emissions at the county level: Influence and prediction” [Ecol. Indic. 145 (2022) 109601]

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Ecological Indicators 2023年 146卷

作者： Chuyu Xia Zhaoyingzi Dong Peng Wu Feng Dong Kai Fang Qiang Li Xiaoshun Li Zhuang Shao Zhenning Yu Faculty of Architecture Civil and Transportation Engineering Beijing University of Technology Beijing 100124 China Key Laboratory of Ocean Space Resource Management Technology MNR Hangzhou Zhejiang 310007 China State Key Joint Laboratory of Environmental Simulation and Pollution Control School of Environment Beijing Normal University Beijing 100875 China School of Public Affairs Zhejiang University Zhejiang 310058 China School of Economics Zhejiang University Hangzhou Zhejiang 310058 China School of Economics and Management China University of Mining and Technology Xuzhou 221116 China Research Center for Transition Development and Rural Revitalization of Resource-based Cities in China China University of Mining and Technology Xuzhou 221116 China School of Landscape Architecture Beijing Forestry University Beijing 100083 China School of Social and Public Administration East China University of Science and Technology Shanghai 200237 China

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Semi-physical simulation experiment on the on-orbit capture of tumbling uncooperative target spacecraft 69

Semi-physical simulation experiment on the on-orbit capture ...

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69th International Astronautical Congress: #InvolvingEveryone, IAC 2018

作者： Xie, Yongchun Wang, Yunpeng Yang, Baohua Beijing Institute of Control Engineering Beijing100190 China Science and Technology on Space Intelligent Control Laboratory Beijing China Tianjin Key Laboratory of Microgravity and Hypogravity Environment Simulation Technology Tianjin100190 China China Aerospace Science and Technology Corporation Beijing China

A semi-physical simulation experiment is introduced in this paper. The experiment simulates the on-orbit capture of tumbling uncooperative target satellite. The chaser spacecraft (or service spacecraft) is a satellite equipped with a 7 degree of freedom (DOF) manipulator and a relative pose measure sensor. A capture tool is installed at the end of the manipulator. It can capture the nozzle of the target. The relative posse measure sensor can measure the relative position and attitude between the chaser and target spacecrafts. The experiment is carried out on a novel semi-physical simulation system, whose core equipment is a novel 9 DOF motion simulator platform. One main feature of this simulator is that it can simulate the tumbling motion of the satellite. Copyright © 2018 by the International Astronautical Federation (IAF). All rights reserved.

关键词： Manipulators

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ALMA Observations of the DART Impact: Characterizing the Ejecta at Sub-Millimeter Wavelengths

arXiv

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arXiv 2023年

作者： Roth, Nathan X. Milam, Stefanie N. Remijan, Anthony J. Cordiner, Martin A. Busch, Michael W. Thomas, Cristina A. Rivkin, Andrew S. Moullet, Arielle Roush, Ted L. Siebert, Mark A. Li, Jian-Yang Fahnestock, Eugene G. Trigo-Rodríguez, Josep M. Opitom, Cyrielle Hirabayashi, Masatoshi Solar System Exploration Division Astrochemistry Laboratory Code 691 NASA Goddard Space Flight Center 8800 Greenbelt Rd. GreenbeltMD20771 United States Department of Physics The Catholic University of America 620 Michigan Ave. N.E. WashingtonDC20064 United States National Radio Astronomy Observatory 520 Edgemont Rd CharlottesvilleVA22903 United States SETI Institute 189 Bernardo Avenue Suite 200 Mountain ViewCA94043 United States Northern Arizona University Department of Astronomy and Planetary Science P.O. Box 6010 FlagstaffAZ86011 United States Johns Hopkins University Applied Physics Laboratory 11100 Johns Hopkins Rd. LaurelMD20723 United States Planetary Systems Branch MS 245-3 Moffett FieldCA94035 United States Department of Astronomy University of Virginia CharlottesvilleVA22904 United States Planetary Science Institute 1700 East Fort Lowell Suite 106 TucsonAZ85719 United States Jet Propulsion Laboratory California Institute of Technology PasadenaCA91109 United States Campus UAB Carrer de Can Magrans s/n Barcelona Catalonia Cerdanyola del Vallés08193 Spain Institute for Astronomy University of Edinburgh Royal Observatory EdinburghEH9 3HJ United Kingdom Department of Aerospace Engineering Department of Geosciences Auburn University AuburnAL United States Daniel Guggenheim School of Aerospace Engineering Georgia Institute of Technology AtlantaGA United States

We report observations of the Didymos-Dimorphos binary asteroid system using the Atacama Large Millimeter/Submillimeter Array (ALMA) and the Atacama Compact Array (ACA) in support of the Double Asteroid Redirection Test (DART) mission. Our observations on UT 2022 September 15 provided a pre-impact baseline and the first measure of Didymos-Dimorphos’ spectral emissivity at λ = 0.87 mm, which was consistent with the handful of siliceous and carbonaceous asteroids measured at millimeter wavelengths. Our post-impact observations were conducted using four consecutive executions each of ALMA and the ACA spanning from T+3.52 to T+8.60 hours post-impact, sampling thermal emission from the asteroids and the impact ejecta. We scaled our pre-impact baseline measurement and subtracted it from the post-impact observations to isolate the flux density of mm-sized grains in the ejecta. Ejecta dust masses were calculated for a range of materials that may be representative of Dimorphos’ S-type asteroid material. The average ejecta mass over our observations is consistent with 1.3–6.4×107 kg, with the lower and higher values calculated for amorphous silicates and for crystalline silicates, respectively. Owing to the likely crystalline nature of S-type asteroid material, the higher value is favored. These ejecta masses represent 0.3–1.5% of Dimorphos’ total mass and are in agreement with lower limits on the ejecta mass based on measurements at optical wavelengths. Our results provide the most sensitive measure of mm-sized material in the ejecta and demonstrate the power of ALMA for providing supporting observations to spaceflight missions. © 2023, CC BY.

关键词： Radio astronomy

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Corrigendum: provincial-scale assessment of direct air capture to meet China’s climate neutrality goal under limited bioenergy supply (2024 Environ. Res. Lett. 19 114021)

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Environmental Research Letters 2025年第2期20卷 029502-029502页

作者： Hanwoong Kim Yang Qiu Haewon McJeon Andres Clarens Parisa Javadi Can Wang Rui Wang Jiachen Wang Hanying Jiang Andy Miller Ryna Cui Jenna Behrendt Yang Ou Sha Yu Jay Fuhrman Joint Global Change Research Institute University of Maryland and Pacific Northwest National Laboratory College Park MD 20740 United States of America Graduate School of Green Growth and Sustainability (GGGS) Korea Advanced Institute of Science and Technology 291 Daehak-ro Yuseong-gu Daejeon 34141 Republic of Korea University of Virginia Department of Civil and Environmental Engineering University of Virginia Charlottesville VA 22904 United States of America State Key Joint Laboratory of Environment Simulation and Pollution Control School of Environment Tsinghua University Beijing 100084 People’s Republic of China Department of Earth System Science Ministry of Education Key Laboratory for Earth System Modelling Institute for Global Change Studies Tsinghua University Beijing 100084 People’s Republic of China Center for Global Sustainability School of Public Policy University of Maryland College Park MD United States of America College of Environmental Sciences and Engineering Peking University Beijing People’s Republic of China Institute of Carbon Neutrality Peking University Beijing People’s Republic of China

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Learning a Faster Locomotion Gait for a Quadruped Robot with Model-Free Deep Reinforcement Learning

Learning a Faster Locomotion Gait for a Quadruped Robot with...

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IEEE International Conference on Robotics and Biomimetics

作者： Biao Hu Shibo Shao Zhengcai Cao Qing Xiao Qunzhi Li Chao Ma College of Information Science and Technology Beijing University of Chemical Technology Beijing China Beijing Key Laboratory of Intelligent Space Robotic Systems Technology and Applications Beijing Institute of Spacecraft System Engineering Beijing China

Quadruped robots have great agility, flexibility and stability, which enables them to walk through uneven terrain. Motion control of legged robots is always a difficult problem. Previous approaches mostly either use a predefined gait that results in clumsy and unnatural behavior, or use reinforcement learning approach to generate a gait strategy that needs longtime computation and elegant network design. In this paper, we present an effective approach that uses deep reinforcement learning with prior knowledge to optimize the gait of quadruped robot. By using a specific quadruped robot walking gait as a priori knowledge, this approach adopts the technique of distributed proximal policy optimization to optimize the search for better gait. The proposed approach does not require modelling of complex robots, and has good network convergence speed and learning effect. simulation results demonstrate that our proposed approach converges faster than other deep reinforcement learning methods without prior knowledge. Besides, our achieved gait has higher speed that is 50% faster than the trot gait without optimization.

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ANTARCTICA AND THE SOUTHERN OCEAN

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BULLETIN OF THE AMERICAN METEOROLOGICAL SOCIETY 2023年第9期104卷 S322-S365页

作者： Clem, Kyle R. Raphael, Marilyn N. School of Geography Environment and Earth Sciences Victoria University of Wellington Wellington New Zealand Scripps Institution of Oceanography University of California San Diego La Jolla California Department of Atmospheric and Oceanic Sciences University of Colorado Boulder Boulder Colorado Earth Science Observation Center Cooperative Institute for Research in Environmental Sciences (ESOC/CIRES) University of Colorado Boulder Boulder Colorado Argentine Naval Hydrographic Service Buenos Aires Argentina Department of Earth and Environmental Science Temple University Philadelphia Pennsylvania Department of Meteorology University of Valparaíso Valparaíso Chile Center for Climate and Resilience Research (CR)2 Santiago Chile British Antarctic Survey Cambridge United Kingdom Science Systems and Applications Inc. Lanham Maryland NASA Goddard Space Flight Center Greenbelt Maryland Royal Netherlands Meteorological Institute (KNMI) DeBilt The Netherlands Department of Marine Sciences University of Gothenburg Gothenburg Sweden Department of Geography Ohio University Athens Ohio NASA Jet Propulsion Laboratory Pasadena California NOAA/OAR Earth System Research Laboratory Global Monitoring Division Boulder Colorado University of Colorado Boulder Boulder Colorado National Oceanography Centre Southampton United Kingdom. Antarctic Meteorological Research and Data Center Space Science and Engineering Center University of Wisconsin-Madison Madison Wisconsin Department of Physical Sciences School of Arts and Sciences Madison Area Technical College Madison Wisconsin Australian Bureau of Meteorology and Institute for Marine and Antarctic Studies (IMAS) University of Tasmania Hobart Australia Earth Science and Observation Center CIRES University of Colorado Boulder Colorado University of St. Andrews St Andrews United Kingdom Princeton University Princeton New Jersey Australian Antarctic Division Australian Antarctic Program Partnership (AAPP) and Australian Centre fo

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Balancing the QOS and security in dijkstra algorithm by SDN technology 1

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15th IFIP International Conference on Network and Parallel Computing, NPC 2018

作者： JinJing, Zhao Pang, Ling Kuang, Xiaohui Jin, Rong National Key Laboratory of Science and Technology on Information System Security Beijing100101 China Beijing Space Information Relay and Transmission on Technology Centre Beijing100094 China

ISBN: (数字)9783030056773

ISBN: (纸本)9783030056766

Dijkstra algorithm is widely used in a lot of common network routing protocols. We consider the problem of quality of service (QoS) and the Security features of the network routing area using software defined networks (SDN). The SDN framework enables an efficient decoupled implementation of dynamic routing protocols which could aware the communication network status. In this work we consider the varying delay status of the communication network along with other network security parameters. The routing problem is formulated as a multi-constrained shortest path problem. A new improved Dijkstra algorithm is presented named as QS-Dijkstra. The implement and experiment show that QS-Dijkstra algorithm is able to minimize traffic routing through vulnerable links while satisfying the QoS constraints of the network. © IFIP International Federation for Information Processing 2018.

关键词： Network security

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Publisher Correction: Ozone pollution mitigation strategy informed by long-term trends of atmospheric oxidation capacity

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Nature Geoscience 2024年 172页

作者： Wenjie Wang Xin Li Ying Liu Sihua Lu Yusheng Wu Shiyi Chen Keding Lu Min Hu Limin Zeng Min Shao Yuanhang Zhang Hang Su Yafang Cheng Ruijing Ni Ulrich Pöschl Zhaofeng Tan Franz Rohrer Andreas Wahner David D. Parrish Cheng Huang Xudong Tian K. M. Leung Liangfu Chen Meng Fan Qiang Zhang State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and Engineering Peking University Beijing China State Key Laboratory of Atmospheric Environment and Extreme Meteorology Institute of Atmospheric Physics Chinese Academy of Sciences Beijing China Max Planck Institute for Chemistry Mainz Germany International Joint Laboratory for Regional Pollution Control Ministry of Education Beijing China Collaborative Innovation Centre of Atmospheric Environment and Equipment Technology Nanjing University of Information Science & Technology Nanjing China Institute of Carbon Neutrality Peking University Beijing China Institute for Environmental and Climate Research Jinan University Guangzhou China State Environmental Protection Key Laboratory of Formation and Prevention of Urban Air Pollution Complex Shanghai Academy of Environmental Sciences Shanghai China Institut für Energie-und Klimaforschung: Troposphäre (IEK-8) Forschungszentrum Jülich Jülich Germany Key Laboratory of Ecological and Environmental Monitoring Forewarning and Quality Control of Zhejiang Zhejiang Ecological and Environmental Monitoring Center Hangzhou China Environmental Protection Department The Government of the Hong Kong Special Administrative Region Hong Kong China State Key Laboratory of Remote Sensing Science The Aerospace Information Research Institute Chinese Academy of Sciences Beijing China Department of Earth System Science Tsinghua University Beijing China

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