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3rd IEEE International Conference on Data science in Cyberspace, DSC 2018

作者： Zhao, Zhongwen Li, Zhangyuan Guo, Huanghuang Yang, Miaoben Space Engineering University Science and Technology On Complex Electronic System Simulation Laboratory Beijing China 63710 troops Taiyuan China

ISBN: (纸本)9781538642108

With the development and growing applications of information technology, the coupling and dependency of space information network are becoming more and more intense. In this paper, the vulnerability of space information network coupled with the communication network and function network is studied. Aiming at the shortage of traditional attack model, we put forward physical-attack and cyber-attack and set up different attack strategies such as random attack, targeted attack and gray attack. The concept of combat component is proposed and the cascading failure algorithm is given. The simulation shows that compared with traditional single network model, the interdependent network model based on the combat component can more accurately reflect the cascading failure mechanism of the space information network. This research results can provide guidance for space information network security research and invulnerability design. © 2018 IEEE.

关键词： Network security

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Hyperspectral image denoising base on adaptive sparse representation 3

Hyperspectral image denoising base on adaptive sparse repres...

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3rd IEEE International Conference on Data science in Cyberspace, DSC 2018

作者： Song, Xiaorui Wu, Lingda Hao, Hongxing Graduate School Space Engineering University Beijing China Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing China

ISBN: (纸本)9781538642108

The hyperspectral image(HSI) generated by most imaging spectrometer systems is constantly disturbed by noise. In this research, we introduced an HSI denoising method based on the theory of sparse coding extended to the spectral domain. The algorithm employs variable separation method and augmented Lagrangian method in sparse coding and constitutes the adaptive dictionary from the pixel spectral vectors extracted from the noisy image. Our results demonstrate that the HSI denoising performance is related to the sparsity of the representation. The effectiveness of the new adaptive sparse coding based approach to hyperspectral denoising, termed HyDeASp, is illustrated in a series of experiments on synthetic and real-world data where it outperforms the state-of-the-art. © 2018 IEEE.

关键词： Image denoising

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Design and modeling of satellite network structure for business scenarios

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Journal of Physics: Conference Series 2020年第1期1684卷

作者： Lintao Ren Zhongmin Pei Wei Xiong Zhangkai Luo Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing 101416 China

In view of the actual decentralized development of the satellite service constellation and the trend of space-ground integrated information network, based on the idea of clustering, methodology of complex network community structure, a business scenario-oriented satellite network structure is designed. On the one hand, it reflects the different separation and integration of satellite constellations in business scenarios. On the other hand, the 'head node' mechanism is introduced to be responsible for the interaction between constellation in different business scenarios. The satellite network structure is modeled using the growth and priority connection mechanism, and through computational derivation and simulation validation, the scale-free characteristics of the satellite network are revealed. Finally, through the simulation experiments on different satellite network parameters, the effect of different parameters on the static geometry, network efficiency, etc., are obtained. The influence of the law of the network will provide theoretical and methodological reference for the design of satellite network structure.

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The influence of thermal annealing on microstructure and resistivity of Pt films with different thickness

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Thin Solid Films 2025年

作者： Lingcong Zhang Wei Chen Li Qiao Qifeng Cui Zhiqing Qiang Peng Wang State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical Physics Chinese Academy of Sciences Lanzhou 730000 PR China University of Chinese Academy of Sciences Beijing 100049 PR China Shandong Laboratory of Advanced Materials and Green Manufacturing at Yantai Yantai 264006 PR China Institute of Aerospace System Engineering Shanghai Shanghai 201108 PR China Space Structure and Mechanism Technology Laboratory of China Aerospace Science and Technology Group Co. Ltd Shanghai 201108 PR China

The thermal stability of platinum film dominates the performance when the film electrodes operate under extreme conditions, such as high temperature. In this study, Pt films with thicknesses of 50, 200, and 400 nm were deposited by magnetron sputtering and annealed in different conditions to investigate the microstructure and resistivity changes. The results show that thicker films exhibit superior dewetting resistance. For Pt films with 50 nm thickness, bumps and pits appear at the surface after vacuum annealing at 773 K, while the bumps grow and the pits transform into voids at 973 K. These defects further expand and separate the films into island-like structures at 1173 K. Voids appear at the surface of Pt-200 after vacuum annealing at 1173 K and atmospheric annealing at 1073 K, which appear at the surface of Pt-400 after vacuum and atmospheric annealing at 1173 K, and island-like structures are observed at 1273 K. Pt films exhibit superior thermal stability in atmospheric environment. All films develop numerous isolated island-like structures at surfaces after vacuum annealing at 1273 K, while only Pt-50 exhibits a surface with a serpentine structure after atmospheric annealing at 1273 K. Below 873 K, the film resistivity decreases with the temperature increasing, primarily driven by recrystallization-mediated elimination of lattice defects such as grain boundaries, dislocations, and vacancies. Above 873 K, the film resistivity increases with the temperature increasing, because dewetting damages the film's structural integrity. These findings provide key design guidelines for Pt-based components operating in harsh working environment to explore the method to improve the high temperature stability of Pt films, and optimize the magnetron sputtering process and guide the application in temperature sensitive devices.

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The Ni isotopic composition of Ryugu reveals a common accretion region for carbonaceous chondrites

arXiv

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arXiv 2024年

作者： Spitzer, Fridolin Kleine, Thorsten Burkhardt, Christoph Hopp, Timo Yokoyama, Tetsuya Abe, Yoshinari Aléon, Jérôme OD. Alexander, Conel M. Amari, Sachiko Amelin, Yuri Bajo, Ken-Ichi Bizzarro, Martin Bouvier, Audrey Carlson, Richard W. Chaussidon, Marc Choi, Byeon-Gak Dauphas, Nicolas Davis, Andrew M. Rocco, Tommaso Di Fujiya, Wataru Fukai, Ryota Gautam, Ikshu Haba, Makiko K. Hibiya, Yuki Hidaka, Hiroshi Homma, Hisashi Hoppe, Peter Huss, Gary R. Ichida, Kiyohiro Iizuka, Tsuyoshi Ireland, Trevor R. Ishikawa, Akira Itoh, Shoichi Kawasaki, Noriyuki Kita, Noriko T. Kitajima, Kouki Komatani, Shintaro Krot, Alexander N. Liu, Ming-Chang Masuda, Yuki Morita, Mayu Moynier, Fréderic Motomura, Kazuko Nakai, Izumi Nagashima, Kazuhide Nguyen, Ann Nittler, Larry Onose, Morihiko Pack, Andreas Park, Changkun Piani, Laurette Qin, Liping Russell, Sara S. Sakamoto, Naoya Schönbächler, Maria Tafla, Lauren Tang, Haolan Terada, Kentaro Terada, Yasuko Usui, Tomohiro Wada, Sohei Wadhwa, Meenakshi Walker, Richard J. Yamashita, Katsuyuki Yin, Qing-Zhu Yoneda, Shigekazu Young, Edward D. Yui, Hiroharu Zhang, Ai-Cheng Nakamura, Tomoki Naraoka, Hiroshi Noguchi, Takaaki Okazaki, Ryuji Sakamoto, Kanako Yabuta, Hikaru Abe, Masanao Miyazaki, Akiko Nakato, Aiko Nishimura, Masahiro Okada, Tatsuaki Yada, Toru Yogata, Kasumi Nakazawa, Satoru Saiki, Takanao Tanaka, Satoshi Terui, Fuyuto Tsuda, Yuichi Watanabe, Sei-Ichiro Yoshikawa, Makoto Tachibana, Shogo Yurimoto, Hisayoshi Max Planck Institute for Solar System Research Justus-von-Liebig-Weg 3 Göttingen37077 Germany Department of Earth and Planetary Sciences Tokyo Institute of Technology Tokyo152-8551 Japan Graduate School of Engineering Materials Science and Engineering Tokyo Denki University Tokyo120-8551 Japan Institut de Minéralogie de Physique des Matériaux et de Cosmochimie Sorbonne Université Museum National d'Histoire Naturelle CNRS UMR 7590 IRD Paris75005 France Earth and Planets Laboratory Carnegie Institution for Science WashingtonDC20015 United States McDonnell Center for the Space Sciences and Physics Department Washington University 35 St. LouisMO63130 United States Geochemical Research Center The University of Tokyo Tokyo113-0033 Japan Guangzhou Institute of Geochemistry Chinese Academy of Sciences GD Guangzhou510640 China Departement of Natural History Sciences Hokkaido University Sapporo001-0021 Japan Centre for Star and Planet Formation Globe Institute University of Copenhagen Copenhagen1350 Denmark Bayerisches Geoinstitut Universität Bayreuth Bayreuth95447 Germany Université Paris Cité Institut de Physique du Globe de Paris CNRS Paris75005 France Department of Earth Science Education Seoul National University Seoul08826 Korea Republic of Department of the Geophysical Sciences Enrico Fermi Institute The University of Chicago 5734 South Ellis Avenue Chicago60637 United States Faculty of Geosciences and Geography University of Göttingen GöttingenD-37077 Germany Faculty of Science Ibaraki University Mito310-8512 Japan ISAS/JSEC JAXA Sagamihara252-5210 Japan Research Center for Advanced Science and Technology The University of Tokyo Tokyo153-8904 Japan Research Institute for Marine Resources Utilization Japan Agency for Marine-Earth Science and Technology Kanagawa237-0061 Japan Departement of Earth and Planetary Sciences Nagoya University Nagoya464-8601 Japan Osaka Application Laboratory SBUWDX Rigaku Corporation Osaka569-1

The isotopic compositions of samples returned from Cb-type asteroid Ryugu and Ivuna-type (CI) chondrites are distinct from other carbonaceous chondrites, which has led to the suggestion that Ryugu/CI chondrites formed in a different region of the accretion disk, possibly around the orbits of Uranus and Neptune. We show that, like for Fe, Ryugu and CI chondrites also have indistinguishable Ni isotope anomalies, which differ from those of other carbonaceous chondrites. We propose that this unique Fe and Ni isotopic composition reflects different accretion efficiencies of small FeNi metal grains among the carbonaceous chondrite parent bodies. The CI chondrites incorporated these grains more efficiently, possibly because they formed at the end of the disk’s lifetime, when planetesimal formation was also triggered by photoevaporation of the disk. Isotopic variations among carbonaceous chondrites may thus reflect fractionation of distinct dust components from a common reservoir, implying CI chondrites/Ryugu may have formed in the same region of the accretion disk as other carbonaceous chondrites. © 2024, CC BY.

关键词： Nickel

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The Extreme space Weather Event of 1872 February: Sunspots, Magnetic Disturbance, and Auroral Displays

arXiv

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arXiv 2024年

作者： Hayakawa, Hisashi Cliver, Edward W. Clette, Frédéric Ebihara, Yusuke Toriumi, Shin Ermolli, Ilaria Chatzistergos, Theodosios Hattori, Kentaro Knipp, Delores J. Blake, Séan P. Cauzzi, Gianna Reardon, Kevin Bourdin, Philippe-A Just, Dorothea Vokhmyanin, Mikhail Matsumoto, Keitaro Miyoshi, Yoshizumi Ribeiro, José R. Correia, Ana P. Willis, David M. Wild, Matthew N. Silverman, Sam M. Institute for Space-Earth Environmental Research and Institute for Advanced Researches Nagoya University Nagoya4648601 Japan Science and Technology Facilities Council RAL Space Rutherford Appleton Laboratory Harwell Campus DidcotOX11 0QX United Kingdom National Solar Observatory BoulderCO80303 United States World Data Center SILSO Observatoire Royal de Belgique Brussels1180 Belgium Research Institute for Sustainable Humanosphere Kyoto University Uji6100011 Japan Unit of Synergetic Studies for Space Kyoto University Kyoto6068306 Japan Institute of Space and Astronautical Science Japan Aerospace Exploration Agency Kanagawa Sagamihara2525210 Japan INAF Osservatorio Astronomico di Roma Monte Porzio CatoneI-00078 Italy Max Planck Institute for Solar System Research GöttingenD-37077 Germany Faculty of Societal Safety Sciences Kansai University Takatsuki5691116 Japan Smead Aerospace Engineering Sciences Department 429 UCB University of Colorado Boulder BoulderCO80309 United States Heliophysics Science Division NASA Goddard Space Flight Center GreenbeltMD United States Catholic University of America WashingtonDC United States University of Graz Institute of Physics Universitätsplatz 5 Graz8010 Austria Institut für Weltraumforschung Österreichische Akademie der Wissenschaften Graz8042 Austria University of Oulu OuluFI-90014 Finland Escola Secundária Henrique Medina Esposende Av. Dr. Henrique Barros Lima Esposende4740-203 Portugal 18 Ingleside Road LexingtonMA02420 United States

We review observations of solar activity, geomagnetic variation, and auroral visibility for the extreme geomagnetic storm on 1872 February 4. The extreme storm (referred to here as the Chapman-Silverman storm) apparently originated from a complex active region of moderate area (≈ 500 μsh) that was favorably situated near disk center (S19° E05°). There is circumstantial evidence for an eruption from this region at 9-10 UT on 1872 February 3, based on the location, complexity, and evolution of the region, and on reports of prominence activations, which yields a plausible transit time of ≈29 hr to Earth. Magnetograms show that the storm began with a sudden commencement at ≈14:27 UT and allow a minimum Dst estimate of £ −834 nT. Overhead aurorae were credibly reported at Jacobabad (British India) and Shanghai (China), both at 19°.9 in magnetic latitude (MLAT) and 24°.2 in invariant latitude (ILAT). Auroral visibility was reported from 13 locations with MLAT below |20|° for the 1872 storm (ranging from |10°.0|-|19°.9| MLAT) versus one each for the 1859 storm (|17°.3| MLAT) and the 1921 storm (|16.°2| MLAT). The auroral extension and conservative storm intensity indicate a magnetic storm of comparable strength to the extreme storms of 1859 September (25°.1 ± 0°.5 ILAT and −949 ± 31 nT) and 1921 May (27°.1 ILAT and −907 ± 132 nT), which places the 1872 storm among the three largest magnetic storms yet observed. © 2024, CC BY.

关键词： Geomagnetism

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A TPAA-SBFE Based Partitioning Algorithm for Structural Viscoelastic Dynamic Analysis With Cyclic Symmetry

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International Journal for Numerical Methods in Engineering 2025年第11期126卷

作者： Yang Yu Chongshuai Wang Ean Tat Ooi Sundararajan Natarajan Haitian Yang State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial Equipment Department of Engineering Mechanics International Research Centre for Computational Mechanics Dalian University of Technology Dalian China College of Civil Engineering Jilin Jianzhu University Changchun China State Key Laboratory of Intelligent Power Distribution Equipment and System School of Electrical Engineering Hebei University of Technology Tianjin China Institute of Innovation Science and Sustainability Federation University Australia Ballarat Australia Integrated Modelling and Simulation Lab Department of Mechanical Engineering Indian Institute of Technology Chennai India

An innovative and efficient reduced order algorithm is proposed for the dynamic analysis of 2-D and 3-D viscoelastic structures featuring cyclic symmetry, which is applicable to complete cyclically symmetric structures with or without common nodes, as well as incomplete cyclically symmetric structures. The proposed algorithm is developed on a recursive platform based on TPAA-SBFEM and inherits all the advantages of TPAA-SBFEM. For complete cyclically symmetric structures with or without common nodes, the global stiffness and mass matrices are proved to be block-circulant and can be generated via a cyclically symmetric part instead of the whole domain. And then a recursive partitioning algorithm is rendered, such that the solution scale and computational cost can be efficiently reduced via solving a series of independent problems with small scales. For incomplete cyclically symmetric structures, the complete cyclic symmetry and Woodbury formula are utilized to reduce computational expense. Four numerical examples are provided to elucidate the effectiveness and efficiency of the proposed approach with satisfactory results.

关键词： cyclically symmetric dynamic analysis partitioning algorithm scaled boundary finite element method (SBFEM) viscoelasticity Woodbury formula

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Recent Widespread Deceleration of Global Surface Urban Heat Islands Unveiled by Satellites

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Geophysical Research Letters 2025年第12期52卷

作者： Wenfeng Zhan Long Li T. C. Chakraborty Leiqiu Hu Dazhong Wang Weilin Liao Shasha Wang Huilin Du Fan Huang Chunli Wang Zihan Liu Manchun Li Jiangsu Provincial Key Laboratory for Advanced Remote Sensing and Geographic Information Technology International Institute for Earth System Science Nanjing University Nanjing China Jiangsu Center for Collaborative Innovation in Geographical Information Resource Development and Application Nanjing China Frontiers Science Center for Critical Earth Material Cycling Nanjing University Nanjing China Pacific Northwest National Laboratory Richland WA USA Department of Atmospheric Science University of Alabama in Huntsville Huntsville AL USA Guangdong Key Laboratory for Urbanization and Geo-Simulation School of Geography and Planning Sun Yat-sen University Guangzhou China School of Geography and Ocean Science Nanjing University Nanjing China

Tracking the temporal dynamics of urban heat island (UHI) is critical for urban heat adaptation and mitigation strategies. However, whether UHI trends have shifted recently and their underlying drivers remain unknown. Here we investigate the variabilities in surface UHI trends and their associated determinants in 2,104 cities worldwide from 2000 to 2022. Our findings reveal that approximately half of the world's cities have experienced notable shifts in surface UHI trends, predominantly characterized by UHI deceleration. These shifts can be primarily attributed to alterations in vegetation trends during the day and to modifications in surface albedo and local warming trends at night. Our study challenges the conventional linear models commonly employed to estimate surface UHI trends, suggesting potential biases in such estimates. Our findings underscore the need for nuanced policies to curtail UHI growth by considering changes in urban underlying surfaces and background climate, particularly from a nonlinear perspective. Satellite records reveal that almost half of the world's cities experienced changes in urban heat island (UHI) trends, mainly slowdowns The UHI deceleration occurs at a more rapid speed in larger cities and old urban area as compared to smaller cities and newly urbanized area The changes in UHI trends are intricately regulated by nonlinear changes in urbanization processes and background climate changes Cities worldwide have witnessed a pervasive upward trend in surface urban heat island (UHI). However, it remains unclear whether this trend has changed. Here we reveal approximately half of the world's cities experiencing significant shifts in surface UHI trends, primarily characterized by deceleration. These shifts are mainly regulated by local changes in vegetation, albedo and air temperature. Our research underscores the limited understanding of temporal dynamics of surface UHI, offering the first indication of global prevalence of nonlinear trend

关键词： urban heat island land surface temperature interannual variation urban heat mitigation urban renewal

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Complementary Coordinated Dispatch of Multi-energy systems Considering Power Flexibility Margin

Complementary Coordinated Dispatch of Multi-energy Systems C...

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2019 IEEE PES Innovative Smart Grid Technologies Asia, ISGT 2019

作者： Xiao, Bai Xiao, Zhiwen Yan, Gangui Jiang, Zhuo Wang, Maochun Yang, Hongzhi Dong, Ling Key Laboratory of Modern Power System Simulation and Control Renewable Energy Technology Northeast Electric Power University Jilin China School of Computer Science and Technology Beihua University Jilin China State Grid Qinghai Electric Power Company Xining China

ISBN: (纸本)9781728135205

In the light of wind and photovoltaic curtailment caused by the lack of flexibility in multi-energy power systems, a method for measuring the flexibility margin of power source is proposed. Aiming at the lowest cost of fuel and atmospheric emission control, a coordinated optimal dispatching model of wind, photovoltaic, hydropower and thermal was constructed. Flexibility balance constraints are introduced into the model, and the model is divided into three dispatching layers: non- water renewable energy, hydropower and thermal power. The net load is updated step by step. Heuristic algorithm is used to determine the thermal power unit combination and particle swarm optimization algorithm is improved to optimize the unit output. Taking a provincial power grid in China as an example, the calculation results show that the model and method can not only as far as possible utilize renewable energy, but also reduce system redundancy and environmental pollution. © 2019 IEEE.

关键词： Heuristic algorithms

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Claimed detection of PH3 in the clouds of Venus is consistent with mesospheric SO2

arXiv

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arXiv 2021年

作者： Lincowski, Andrew P. Meadows, Victoria S. Crisp, David Akins, Alex B. Schwieterman, Edward W. Arney, Giada N. Wong, Michael L. Steffes, Paul G. Parenteau, M. Niki Domagal-Goldman, Shawn Department of Astronomy and Astrobiology Program University of Washington Box 351580 SeattleWA98195 United States NASA Nexus for Exoplanet System Science Virtual Planetary Laboratory Team University of Washington Box 351580 SeattleWA98195 United States Jet Propulsion Laboratory California Institute of Technology Earth and Space Sciences Division PasadenaCA91011 United States Jet Propulsion Laboratory California Institute of Technology Instruments Division PasadenaCA91011 United States Department of Earth and Planetary Sciences University of California RiversideCA92521 United States Blue Marble Space Institute of Science SeattleWA United States NASA/Goddard Space Flight Center GreenbeltMD20771 United States School of Electrical and Computer Engineering Georgia Institute of Technology AtlantaGA30332-0250 United States MS 239-4 Space Science Division NASA Ames Research Center Moffett FieldCA United States

The observation of a 266.94 GHz feature in the Venus spectrum has been attributed to PH3 in the Venus clouds, suggesting unexpected geological, chemical or even biological processes. Since both PH3 and SO2 are spectrally active near 266.94 GHz, the contribution to this line from SO2 must be determined before it can be attributed, in whole or part, to PH3. An undetected SO2 reference line, interpreted as an unexpectedly low SO2 abundance, suggested that the 266.94 GHz feature could be attributed primarily to PH3. However, the low SO2 and the inference that PH3 was in the cloud deck posed an apparent contradiction. Here we use a radiative transfer model to analyze the PH3 discovery, and explore the detectability of different vertical distributions of PH3 and SO2. We find that the 266.94 GHz line does not originate in the clouds, but above 80 km in the Venus mesosphere. This level of line formation is inconsistent with chemical modeling that assumes generation of PH3 in the Venus clouds. Given the extremely short chemical lifetime of PH3 in the Venus mesosphere, an implausibly high source flux would be needed to maintain the observed value of 20±10 ppb. We find that typical Venus SO2 vertical distributions and abundances fit the JCMT 266.94 GHz feature, and the resulting SO2 reference line at 267.54 GHz would have remained undetectable in the ALMA data due to line dilution. We conclude that nominal mesospheric SO2 is a more plausible explanation for the JCMT and ALMA data than PH3 © 2021, CC BY.

关键词： Radiative transfer

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