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Service Function Chain Migration in LEO satellite Networks

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China Communications 2024年第3期21卷 247-259页

作者： Geng Yuhui Wang Niwei Chen Xi Xu Xiaofan Zhou Changsheng Yang Junyi Xiao Zhenyu Cao Xianbin School of Electronic and Information Engineering Beihang UniversityBeijing 100191China Key Laboratory of advanced Technology of Near Space Information System Ministry of Industry and Information Technology of ChinaBeijing 100191China Shanghai Key Laboratory of satellite Network Shanghai 201204China Shanghai satellite Network Research Institute Co. Ltd.Shanghai 201204China

With the advancements of software defined network(SDN)and network function virtualization(NFV),service function chain(SFC)placement becomes a crucial enabler for flexible resource scheduling in low earth orbit(LEO)satellite *** due to the scarcity of bandwidth resources and dynamic topology of LEO satellites,the static SFC placement schemes may cause performance degradation,resource waste and even service *** this paper,we consider migration and establish an online migration model,especially considering the dynamic *** the scarcity of bandwidth resources,the model aims to maximize the total number of accepted SFCs while incurring as little bandwidth cost of SFC transmission and migration as *** to its NP-hardness,we propose a heuristic minimized dynamic SFC migration(MDSM)algorithm that only triggers the migration procedure when new SFCs are *** results demonstrate that MDSM achieves a performance close to the upper bound with lower complexity.

关键词： network function virtualization(NFV) resource allocation satellite networks service function chain(SFC) SFC migration SFC placement soft-ware defined network(SDN)

Tunable polarization holographic gratings obtained by varying the ratio of intensities of the recording beams

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Photonics Research 2024年第4期12卷 749-754页

作者： HONG CHEN ZIYAO LYU CHANGSHUN WANG State Key Laboratory of advanced Optical Communication Systems and Networks School of Physics and AstronomyShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Space-Ground Integrated Information Technology Beijing Institute of Satellite Information EngineeringBeijing 100095China

Polarization holography has been extensively applied in many fields, such as optical science, metrology, and biochemistry, due to its property of polarization modulation. However, the modulated polarization state of diffracted light corresponds strictly to that of incident light one by one. Here, a kind of tunable polarization holographic grating has been designed in terms of Jones matrices, and intensity-based polarization manipulation has been realized experimentally. The proposed tunable polarization holographic grating is recorded on an azobenzene liquid-crystalline film by a pair of coherent light beams with orthogonal polarization states and asymmetrically controlled intensities. It is found that the diffracted light can be actively manipulated from linearly to circularly polarized based on the light intensity of the recording holographic field when the polarization state of incident light keeps constant. Our work could enrich the field of light manipulation and holography.

关键词： holographic recording Polarization

Westward Migration of Tropical Cyclone Activity in the Western North Pacific during 1982–2020:Features and Possible Causes

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Journal of Meteorological Research 2024年第1期38卷 1-9页

作者： Jian ZHONG Huadong DU Yuqin WU Yuehua PENG China satellite Maritime Tracking and Control Department Jiangyin 2144312 College of advanced Interdisciplinary Studies National University of Defense TechnologyChangsha 4100733 Dalian Naval Academy Dalian 1160184 Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029

The westward migration of tropical cyclone(TC)activity has been identified in the western North Pacific(WNP),but the related features and causes remain ***,based on the best track data from China,Japan,and the US,and the NCEP–NCAR reanalysis data in 1982–2020,we investigate characteristics of the westward migration of the WNP TC activity with various metrics,and reveal possible causes for the migration of TC tracks through analyzing its seasonality and dependence on environmental *** results show that the WNP TCs show significant westward migrations in a number of metrics,including location of tracks,genesis,the first track point at which TC reaches its lifetime-maximum intensity,and the last track point in the TC *** is found that TC tracks exhibit more significant westward migrations in the easterly steering flow than in the westerly steering ***,the TC longitude shift shows notable seasonal variations,for which the TCs in the easterlies move further west than those in the westerlies during July–September,vice versa during October–*** dependence of the westward migration of TC tracks on background steering flow is associated with the different environmental *** westward shift in the westerly steering is mainly due to the reduced vertical wind shear(VWS),while the weakened zonal easterly steering and reduced VWS are both closely related to the westward migration in the easterly *** results have important implications for understanding current and future variations in TC longitude shift.

关键词： tropical cyclone westward migration steering flow vertical wind shear

Fusion SST from Infrared and Microwave Measurement of FY-3D Meteorological satellite

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Journal of Tropical Meteorology 2024年第1期30卷 89-96页

作者：张淼徐娜陈林 National satellite Meteorological Center/National Center for Space Weather Beijing 100081 China Innovation Center for Fengyun Meteorological satellite(FYSIC) Beijing 100081 China Key Laboratory of Radiometric Calibration and Validation for Environmental satellites China Meteorological AdministrationBeijing 100081 China

Sea surface temperature(SST)is one of the important parameters of global ocean and climate research,which can be retrieved by satellite infrared and passive microwave remote sensing *** satellite infrared SST offers high spatial resolution,it is limited by cloud *** the other hand,passive microwave SST provides all-weather observation but suffers from poor spatial resolution and susceptibility to environmental factors such as rainfall,coastal effects,and high wind *** achieve high-precision,comprehensive,and high-resolution SST data,it is essential to fuse infrared and microwave SST *** this study,data from the Fengyun-3D(FY-3D)medium resolution spectral imager II(MERSI-II)SST and microwave imager(MWRI)SST were ***,the accuracy of both MERSIII SST and MWRI SST was verified,and the latter was bilinearly interpolated to match the 5km resolution grid of MERSI *** pretreatment and quality control of MERSI SST and MWRI SST,a Piece-Wise Regression method was employed to correct biases in MWRI ***,SST data were selected based on spatial resolution and accuracy within a 3-day window of the analysis ***,an optimal interpolation method was applied to fuse the FY-3D MERSI-II SST and MWRI *** results demonstrated a significant improvement in spatial coverage compared to MERSI-II SST and MWRI ***,the fusion SST retained true spatial distribution details and exhibited an accuracy of–0.12±0.74℃compared to OSTIA *** study has improved the accuracy of FY satellite fusion SST products in China.

关键词： SST data fusion FY3 infrared microwave

Operational Characteristics of Loop Heat Pipe in Microgravity and Normal Gravity Environments

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Journal of Thermal Science 2024年第4期33卷 1394-1408页

作者： ZHONG Siyuan XIE Rongjian LI Yunfei SUN Xiaojin Shanghai Institution of Technology and Physics Shanghai200083China University of Chinese Academy of Sciences Beijing100049China Shanghai Institute of satellite Engineering Shanghai200240China

The loop heat pipe(LHP)is an advanced,efficient two-phase heat transfer unit,whose operational performance may be affected by microgravity conditions in contrast to ground-based *** performance of on-orbit temperature data and ground test of a copper-propylene LHP with a condenser temperature range of 243.15 K to 303.15 K were employed to compared and *** LHP has successfully started up for more than 193 times with a good heat transfer performance and a stable start-up stabilization on-orbit under a complex orbital heating environment for more than eight *** a small heat load(10.0W),the average start-up time is 110.0 s while the start-up temperature ranges from 5.71 K-12.78 *** start-up time at large temperature differences in the high temperature zone will be higher than the time required for start-up at smaller temperature differences in the low *** the condenser temperature is 250.0 K,the stable temperature difference on orbit is 3.83 K,which is generally consistent in heat transfer compared to 2.20 K in the ground *** this paper,we can conclude that the on-orbit flight data up to now can provide a reference to the design of subsequent LHP space applications.

关键词： Loop Heat Pipe(LHP) start up microgravity on-orbit experiment

Frequency-dependent Electrical Capacitance and Resistance of Ultra-high Performance Concrete and Their Responses to Compressive Strain

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Journal of Wuhan University of Technology(Materials Science) 2024年第4期39卷 968-978页

作者：吴瑜孙明清 ZHU Lutao SONG Qiulei CHEN Jianzhong Hubei Key Laboratory of Theory and Application of advanced Materials Mechanics School of ScienceWuhan University of TechnologyWuhan 430070China School of Civil Engineering and Architecture Hubei University of Arts and ScienceXiangyang 441053China Suzhou Concrete and Cement products Research Institude Co. LtdSuzhou 215026China

The frequency-dependent electrical properties and strain self-sensing behaviour of ultra-high performance concrete(UHPC)as cement-based stress/strain self-sensing(CBSS)smart materials were investigated in the frequency range from 100 Hz to 300 *** using the electrical parameters of the equivalent electric circuit model,the quantitative relations of capacitance and conductance of CBSS with the measurement frequency were *** capacitance and the conductance exhibit power-law type dependence on the measurement *** calculated capacitance values at frequencies beyond 2 kHz and conductance values are consistent with the experimental *** sweep-frequency test and the fixed-frequency test were performed to examine effects of the excitation frequencies on strain self-sensing properties of *** fractional change in capacitance(FCC)and resistance(FCR)of CBSS are frequency-dependent in the frequency range from 100 Hz to the f_(B),but frequency-independent in the frequency range from the f_(B)to 300 *** f_(A)and the f_(B)are 1.7-4.0 kHz and 11-78 kHz depending on the fiber dosages,*** and FCR reach their maximum at the f_(A)and 100 Hz,*** responses of capacitance and resistance of CBSS to strain show good repeatability during cyclic *** the fiber dosage increases,capacitance-based sensitivity to strain increases initially and then decreases at the f_(A),and resistance-based sensitivity to strain of CBSS increases with increasing fiber contents.

关键词： UHPC strain self-sensing capacitance-based frequency-dependent

Low-cost,large-coverage,and high-flexibility coherent PON for next-generation access networks:advances,challenges,and prospects[Invited]

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Chinese Optics Letters 2024年第4期22卷 26-35页

作者：邢思哲张俊文申王伟颜安李国强孙奥龙周骥郭栋施剑阳李子薇沈超迟楠 Key Laboratory of EMW Information(MoE) Fudan UniversityShanghai 200433China Department of Communication Science and Engineering Shanghai ERC of LEO Satellite Communication and ApplicationsShanghai CIC of LEO Satellite Communication TechnologyFudan UniversityShanghai 200433China Department of Electronic Engineering Jinan UniversityGuangzhou 510632China School of Information and Electronics Beijing Institute of TechnologyBeijing 100081China

Increasing bandwidth requirements have posed significant challenges for traditional access *** is difficult for intensity modulation/direct detection to meet the power budget and flexibility requirements of the next-generation passive optical network(PON)at 100G and beyond considering the new *** is driving researchers to develop novel optical access ***-cost,wide-coverage,and high-flexibility coherent PON is emerging as a strong contender in the *** this article,we will review technologies that reduce the complexity of coherent PON(CPON),enabling it to meet the commercial ***,advanced algorithms and architectures that can enhance system coverage and flexibility are also discussed.

关键词： access network coherent optics flexible data rate low complexity wide dynamic range

Facile and effective synthesis strategy for terbium-doped hydroxyapatite toward photoelectric devices and flexible functional fibers

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Rare Metals 2024年第4期43卷 1713-1723页

作者： Xiao-Dong Zhang Kun Nie Zi-Yao Hu Ran-Ran Zhou Xiu-Qiang Duan Wu-Bin Dai Song-Song Nie Song-Jun Yao Luo-Xin Wang Le-Fu Mei Hua Wang Yi-Yi Yao Xiao-Xue Ma Hubei Key Laboratory for New Textile Materials and Applications and State Key Laboratory of New Textile Materials and advanced Processing Technology School of Materials Science and EngineeringWuhan Textile UniversityWuhan430200China Key Laboratory of Testing and Tracing of Rare Earth products for State Market Regulation Jiangxi University of Science and TechnologyGanzhou341000China Hubei Key Laboratory of Plasma Chemistry and advanced Materials and Key Laboratory of Green Chemical Engineering Process of Ministry of Education Wuhan Institute of TechnologyWuhan430205China

As a material with good biocompatibility,hydroxyapatite(HAP)can have optical properties after doping with various rare earth *** a biocompatible fluorescent material,doped HAP could have broad applications in biological probes,drug delivery,optoelectronic materials,fluorescence anti-counterfeiting,and other *** this paper,we put forward the preparation of HAP doped with terbium(Ⅲ)ions(Tb^(3+))by hydrothermal *** controlling the Tb^(3+)doping content in reaction and the reaction time,the changes in HAP's structure,morphology,and luminescence properties under different conditions were *** the doping amount of Tb^(3+)reached an optimal value,the dipole-quadrupole would occur and the concentration would be *** control experiment showed that the optimal Tb3+content was 7.5×10^(-5)mol,which showed the best fluorescence ***,a non-luminous material,was rarely used in the field of fluorescent anti-counterfeiting and photoelectric *** proposed to prepare a luminescent aramid/polyphenylene sulfide(ACFs/PPS)fiber paper and a new light-emitting diode(LED)using the Tb-doped HAP *** composite sample exhibited an excellent stability and fluorescence performance,which also demonstrated a possibility of HAP applications in anticounterfeiting and *** introduction of Tb3+dopant HAP was done to give HAP optical properties and broaden the application range of HAP.

关键词： Hydroxyapatite Rare earth luminescence Photoelectric device Aramid Polyphenylene sulfide fiber paper Luminescent fiber

Efficient and fair PPO-based integrated scheduling method for multiple tasks of SATech-01 satellite

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Chinese Journal of Aeronautics 2024年第2期37卷 417-430页

作者： Qi SHI Lu LI Ziruo FANG Xingzi BI Huaqiu LIU Xiaofeng ZHANG Wen CHEN Jinpei YU Shanghai satellite Network Research Institute CO. LTDShanghai 201210China Innovation Academy for Microsatellites of Chinese Academy of Sciences Shanghai 201306China University of Chinese Academy of Sciences Beijing 100039China

SATech-01 is an experimental satellite for space science exploration and on-orbit demonstration of advanced *** satellite is equipped with 16 experimental payloads and supports multiple working modes to meet the observation requirements of various *** to the limitation of platform power supply and data storage systems,proposing reasonable mission planning schemes to improve scientific revenue of the payloads becomes a critical *** this article,we formulate the integrated task scheduling of SATech-01 as a multi-objective optimization problem and propose a novel Fair Integrated Scheduling with Proximal Policy Optimization(FIS-PPO)algorithm to solve *** use multiple decision heads to generate decisions for each task and design the action mask to ensure the schedule meeting the platform *** results show that FIS-PPO could push the capability of the platform to the limit and improve the overall observation efficiency by 31.5%compared to rule-based plans currently ***,fairness is considered in the reward design and our method achieves much better performance in terms of equal task *** of its low computational complexity,our task scheduling algorithm has the potential to be directly deployed on board for real-time task scheduling in future space projects.

关键词： satellite observatories SATech-01 Multi-modes platform Scheduling algorithms Reinforcement learning Proximal Policy Optimization(PPO)