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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)

Progress and prospects of graphene-based materials in lithium batteries

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Rare Metals 2024年第5期43卷 1886-1905页

作者： Shen Lai Tao Huang Pei Liu Hong-Bin Wang Shi-Chun Yang Xin-Hua Liu Kai Yang Qian-Ling Zhang Jian-Hong Liu Jiang-Tao Hu Graphene Composite Research Center College of Chemistry and Environmental EngineeringShenzhen UniversityShenzhen 518060China College of Physics and Optoelectronic Engineering Shenzhen UniversityShenzhen 518060China Shenzhen Eigen-Equation Graphene technology Co.ltd Shenzhen518060China School of Transportation Science and Engineering Beihang UniversityBeijing 100191China Department of Electrical and Electronic Engineering Advanced Technology InstituteUniversity of SurreyGuildfordSurrey GU27XHUK

Reasonable design and applications of graphene-based materials are supposed to be promising ways to tackle many fundamental problems emerging in lithium batteries,including suppression of electrode/electrolyte side reactions,stabilization of electrode architecture,and improvement of conductive ***,extensive fundamental research on this aspect has been performed so ***,when it comes to large-scale industrial applications,the utilization of graphene-based materials progresses at a very slow ***,there presents a severe technological decoupling between academic research and industrial application,and there is an urgent need to link ***,in order to address current issues of graphene-based materials used in lithium batteries,we present their latest advancements with stateof-the-art *** applications of graphenebased materials in practical lithium batteries are highlighted and predicted to bridge the gap between the academic progress and industrial manufacture,thereby paving the way for accelerating the development of graphenebased material as well as lithium battery industry.

关键词： Lithium batteries Graphene-based materials Academic research Industrial application Development direction

A Secure Communicating While Jamming Approach for End-to-End Multi-Hop Wireless Communication Network

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Chinese Journal of Electronics 2024年第3期33卷 833-846页

作者： Xiao MA Dan LI Liang WANG Weijia HAN Nan ZHAO School of Physics and Information technology Shaanxi Normal University Beijing Aerospace Science and Industry Century satellite Hi-tech Co. Ltd.Xi'an Branch School of Computer Science Shaanxi Normal University School of Telecommunications Engineering Xidian University

With the rapid development of wireless communications,cellular communication and distributed wireless network are fragile to eavesdropping due to distributed users and transparent ***,to adopt bigger transmit power at a given area to interfere potential eavesdroppers not only incurs huge energy waste but also may suppresses regular communication in this *** this end,we focus on secure communication in multi-hop wireless communication network,and propose two communicating while jamming schemes for secure communication in presence of potential eavesdroppers for the narrow band and broad band point-to-point(P2P) systems respectively with the aid of artificial noise transmitted by a chosen cooperative ***,to achieve the end-to-end(E2E) multi-hop secure communication,we devise the secure network topology discovering *** constructing a proper network topology with at least one proper node as the cooperative interferer in each hop,and then propose the secure transmission path planning scheme to find an E2E secure transmission route from source to destination,*** on the wireless open-access research platform demonstrate the feasibility of the proposed ***,simulations results validate that the proposed schemes can achieve better performance compared with existing methods in both the P2P communication case and E2E multi-hop communication network scenario.

关键词： Wireless communication Network topology Law Simulation Wireless networks Noise Spread spectrum communication

Multi-network-region traffic cooperative scheduling in large-scale LEO satellite networks

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Journal of Systems Engineering and Electronics 2024年第4期35卷 829-841页

作者： LI Chengxi WANG Fu YAN Wei CUI Yansong FAN Xiaodong ZHU Guangyu XIE Yanxi YANG Lixin ZHOU Luming ZHAO Ran WANG Ning School of Electronic Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China The 6th Research Institute of China Electronics Corporation Beijing 102209China China satellite Network Share Operation Co. LtdBeijing 100876China Weihai Electronic Information technology Comprehensive Research Center of the Ministry of Industry and Information technology Weihai 264200 China

A low-Earth-orbit(LEO)satellite network can provide full-coverage access services worldwide and is an essential candidate for future 6G ***,the large variability of the geographic distribution of the Earth’s population leads to an uneven service volume distribution of access ***,the limitations on the resources of satellites are far from being able to serve the traffic in hotspot *** enhance the forwarding capability of satellite networks,we first assess how hotspot areas under different load cases and spatial scales significantly affect the network throughput of an LEO satellite network ***,we propose a multi-region cooperative traffic scheduling *** algorithm migrates low-grade traffic from hotspot areas to coldspot areas for forwarding,significantly increasing the overall throughput of the satellite network while sacrificing some latency of end-to-end *** algorithm can utilize all the global satellite resources and improve the utilization of network *** model the cooperative multi-region scheduling of large-scale LEO *** on the model,we build a system testbed using OMNET++to compare the proposed method with existing *** simulations show that our proposed method can reduce the packet loss probability by 30%and improve the resource utilization ratio by 3.69%.

关键词： low-Earth-orbit(LEO)satellite network satellite communication load balance multi-region scheduling latency optimization

A method for extracting the preseismic gravity anomalies over the Tibetan Plateau based on the maximum shear strain using GRACE data

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Earth and Planetary Physics 2024年第4期8卷 589-608页

作者： Hui Wang DongMei Song XinJian Shan Bin Wang College of Oceanography and Space Informatics China University of Petroleum(East China)Qingdao 266580China PCI technology Group Co. Ltd.Guangzhou 510660China Laboratory for Marine Mineral Resources Qingdao National Laboratory for Marine Science and TechnologyQingdao 266200China State Key Laboratory of Earthquake Dynamics Beijing 100029China

The occurrence of earthquakes is closely related to the crustal geotectonic movement and the migration of mass,which consequently cause changes in *** Gravity Recovery And Climate Experiment(GRACE)satellite data can be used to detect gravity changes associated with large ***,previous GRACE satellite-based seismic gravity-change studies have focused more on coseismic gravity changes than on preseismic gravity ***,the noise of the north–south stripe in GRACE data is difficult to eliminate,thereby resulting in the loss of some gravity information related to tectonic *** explore the preseismic gravity anomalies in a more refined way,we first propose a method of characterizing gravity variation based on the maximum shear strain of gravity,inspired by the concept of crustal *** offset index method is then adopted to describe the gravity anomalies,and the spatial and temporal characteristics of gravity anomalies before earthquakes are analyzed at the scales of the fault zone and plate,*** this work,experiments are carried out on the Tibetan Plateau and its surrounding areas,and the following findings are obtained:First,from the observation scale of the fault zone,we detect the occurrence of large-area gravity anomalies near the epicenter,oftentimes about half a year before an earthquake,and these anomalies were distributed along the fault ***,from the observation scale of the plate,we find that when an earthquake occurred on the Tibetan Plateau,a large number of gravity anomalies also occurred at the boundary of the Tibetan Plateau and the Indian ***,the aforementioned experiments confirm that the proposed method can successfully capture the preseismic gravity anomalies of large earthquakes with a magnitude of less than 8,which suggests a new idea for the application of gravity satellite data to earthquake research.

关键词： Gravity Recovery And Climate Experiment(GRACE)data maximum shear strain offset index K preseismic gravity anomalies Tibetan Plateau fault zone

Thermosphere joint observations by TM-1 constellations and Swarm-B during the April 2023 geomagnetic storm

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Earth and Planetary Physics 2024年第2期8卷 307-316页

作者： YongPing Li YueQiang Sun XianGuo Zhang JiangZhao Ai XiaoLiang Zheng Jia Li YuJie Wang BiBo Guo Feng Yan ShiLong Wei XinChun Tang YuanYuan Cao 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 University of Chinese Academy of Sciences Beijing 100049China Shenzhen Aerospace Dongfanghong satellite LtdShenzhen 518057China

The response of thermosphere density to geomagnetic storms is a complicated physical ***-satellite joint observations at the same altitude but different local times(LTs)are important for understanding this process;however,until now such studies have hardly been *** this report,we analyze in detail the thermosphere mass density response at 510 km during the April 23−24,2023 geomagnetic storm using data derived from the TM-1(TianMu-1)satellite constellation and Swarm-B *** observations show that there were significant LT differences in the hemispheric asymmetry of the thermosphere mass density during the geomagnetic *** observed by satellite TM02 at nearly 11.3 and 23.3 LTs were larger in the northern hemisphere than in the *** TM04 dayside density observations appear to be almost symmetrical with respect to the equator,though southern hemisphere densities on the nightside were ***-B data exhibit near-symmetry between the *** addition,the mass density ratio results show that TM04 nightside observations,TM02 data,and Swarm-B data all clearly show stronger effects in the southern hemisphere,except for TM04 on the dayside,which suggest hemispheric *** South-North density enhancement differences in TM02 and TM04 on dayside can reach 130%,and Swarm-B data even achieve 180%*** the observations of all three satellites,large-scale traveling atmospheric disturbances(TADs)first appear at high latitudes and propagate to low latitudes,thereby disturbing the atmosphere above the equator and even into the opposite ***00 model simulations were also performed on this geomagnetic *** are absent in the NRLMSISE00 *** satellite data suggest that NRLMSISE00 significantly underestimates the magnitude of the density response of the thermosphere during geomagnetic storms,especially at high latitudes in both ***,use of the density simulation of NRLM

关键词： TM-1 constellation Swarm-B joint observations geomagnetic storm Local Times

Study on the vertical deformations induced by terrestrial water storage changes in Huang-Huai-Hai river basin

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Geodesy and Geodynamics 2024年第4期15卷 352-365页

作者： Liansheng Deng Yugang Xiao Qusen Chen Feifei Liao Zhao Li School of Electrical and Electronic Information Engineering Hubei Polytechnic UniversityHuangshi 435003China Hubei Luojia Laboratory GNSS Research CenterWuhan UniversityWuhan 430079.China Changjiang Spatial Information technology Engineering Co. Ltd.Wuhan 430010China

Terrestrial water storage(TWs)variations are associated with water mass movements,which may cause the deformation displacements of the Global Navigation satellite System(GNSS)*** study investigates the spatio-temporal Tws variations and addresses the relationship between deformation variations observed in the Huang-Huai-Hai River Basin(HHHRB)and local hydrological *** indicate that the vertical velocities at the GNSS stations induced by TWS changes are relatively small,and the impacts of the terrestrial water storage changes are mainly reflected in the changes of seasonal *** there is a downward TWS trend from 2011 to 2022 in most HHHRB areas,velocities from the vertical displacements of both Gravity Recovery and Climate Experiment(GRACE)and GRACE Follow-On(GFO)and the GNSS reflect that the HHHRB is undergoing an uplift process,while the magnitude of the GRACE/GFO derived velocities is much smaller than that of the GNSS *** hydrological deformations estimated from GRACE/GFO and GNSS measurements reveal that the TWS-derived displacements can explain 54.5%of the GNSS seasonal variations,with the phases of terrestrial water storage advancing by about one month relative to GNss common signal ***,the decrease of the groundwater storage in the HHHRB has been accelerating since *** reaching its lowest level around mid-2020,it began to rise rapidly,which might be closely related to the implementation of the South-North Water Transfer Central Project.

关键词： Terrestrial waterstorage GRACE GNSS Vertical deformations Huang-Huai-Hairiverbasin

Designing a Dual-Feed Circular Polarization Antenna

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Journal of Electronic Research and Application 2024年第3期8卷 255-261页

作者： Binghao Zeng Haokui Zhu Shenzhen Surbaner technology Co. Ltd.Shenzhen 518000Guangdong ProvinceChina

This paper describes a novel dual-feed circularly polarized antenna,and the dual feeding mode is realized by grooving on the antenna *** antenna utilizes air dielectric material to meet the requirements of low weight and *** results demonstrate that the antenna exhibits capacitive loading between the metal antenna patch and the ground floor,allowing for adjustment of the working frequency of the dual-feed circularly polarized microstrip ***,the original center frequency of 2.264 GHz was reduced to 1.582 GHz,facilitating antenna miniaturization and broad *** a return loss(S11)below-10 dB,a bandwidth of 72 MHz(1.552-1.624 GHz)was ***,the dual-feed microstrip antenna incorporates a 90°bridge,resulting in circular polarization gains of 2.26 dBi at 1.561 GHz and 2.45 dBi at 1.575 ***,the antenna design offers a large working bandwidth and excellent circular polarization characteristics,making it suitable for a wide range of applications in satellite navigation and positioning terminals.

关键词： Air dielectric Circular polarization Dual-feed Microstrip antenna

Performance analysis of the tight combination of GPS, BDS, GALILEO, and QzsS mixed frequencies signals

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Geodesy and Geodynamics 2024年第4期15卷 366-378页

作者： Yu Han Fangjun Qin Xugang Lian Shengliang Wang Leiyuan Qian Wenhua Huang College of Electrical Engineering Naval University of EngineeringWuhan 430033China College of Mining Engineering Taiyuan University of TechnologyTaiyuan 030024China State Key Laboratory of satellite Navigation System and Equipment technology Shijiazhuang 050081China State Key Laboratoryof Geodesy and Earth'sDynamics Innovation AcademyforPrecision Measurement Scienceand Technology Chinese Academy of SciencesWuhan 430077China China Energy Engineering Group Shanxi Electric Power Engineering CO.ltd. Taiyuan 030001China

With the gradual development and modernization of satellite navigation systems,using observation information from multi-GNss has become one of the hot-spot issues in recent ***-system loose combinations form double-difference observation equations within their respective systems,and the positioning effect is ***,the interchangeability and compatible interoperability between global navigation satellite systems(GNSS)cannot be truly *** the same time,when the number of visible satellites decreases abruptly,the positioning performance deteriorates *** paper focuses on the GNsS multi-system tight combination relative positioning technique,gives a mathe-matical model of multi-system tight combination relative positioning considering differential inter-system bias(DISB),and analyzes the time-varying characteristics of DISB at overlapping and non-overlapping frequencies among GPS/Galileo,GPS/BDS,and GPS/QZSS in terms of receiver brand,tem-perature,and receiver *** GNsS tight combination relative positioning performance is verified by static data from Curtin University and dynamic data measured at Taiyuan University of *** results show that compared with loose combination,the ambiguity-fixed rate increases from 62.18%to 97.60%for static data and from 74.97%to 99.53%for dynamic data when the elevation mask angle is 50°,resulting in a significant improvement in positioning performance.

关键词： GNSS Mix frequencies Redundancy Tightcombination Differential inter-system bias