检索结果-南通市图书馆

Science china(Information Sciences) 2025年

作者： Di ZHAO Rui DING Bin SONG State Key Laboratory of Integrated Services networks Xidian University Hangzhou Institute of Technology Xidian University china satellite network group co. Ltd.

Future 6G networks will integrate non-terrestrial co.munication with mobile edge co.puting to enable wide-area edge intelligence, providing ubiquitous co.munication and co.putation services for everyone and everything. In this paper, we introduce the intelligent cloud-edge-device architecture into low Earth orbit (LEO) satellite-supported remote Internet of Things(IoT) networks to facilitate latency-sensitive and co.pute-intensive IoT applications. However, the dynamic spatio-temporal characteristics inherent in LEO satellite networks, such as the high volatility of task traffic and the high mobility of space nodes, pose severe challenges. For efficient task execution, we investigate the joint optimization of cross-region task offloading and cross-domain resource allocation, and innovatively propose a spatio-temporal attention-based proximal policy optimization(STA-PPO) algorithm. Specifically, the temporal attention-based actor network analyzes the timing dependencies of task arrival and makes time-variant decisions. Simultaneously, the spatial attention-based critic network captures the spatial variations of satellite motion and evaluates the topology-related value. We verify the effectiveness of the cloud-edge-device co.laboration through extensive simulations. Numerical results demonstrate that the STA-PPO algorithm outperforms benchmarks, showing the lowest system delay and the highest link throughput.

关键词：

Effect of Bi/Si Ratio of BiBSi Glass on Its Structure, Properties and Laser Sealing Shear Strength for Vacuum Glazing

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 13-24页

作者： LIU Wei JIAO Jinxu LUO Dusha ZHOU Junjie SHI Lifen WANG Weiwei LI Changqing WANG Peng XIONG Dehua LI Hong State Key Laboratory of Silicate Materials for Architectures Wuhan University of TechnologyWuhan 430070China Silica-Based Materials Laboratory of Anhui Province CNBM Research Institute for Advanced Glass Materials Group Co.LtdBengbu 233018China State Key Laboratory of Advanced Technology for Float Glass CNBM Research Institute for Advanced Glass Materials Group Co.LtdBengbu 233018China

The low-melting glass of Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi)system was used for the first time for laser sealing of vacuum *** the co.dition of co.stant boron co.tent,how the structure and properties vary with Bi/Si ratio in low-melting glass was *** addition,the relationships between laser power,low-melting glass solder with different Bi/Si ratios and laser sealing shear strength were *** results show that a decrease in the Bi/Si ratio can cause a co.traction of the glass network of the low-melting glass,leading to an increase of its characteristic temperature and a decrease of its co.fficient of thermal *** laser sealing,the co.per ions in the low-melting glass play an endothermic role.A change in the Bi/Si ratio will affect the valence state transition of the co.per ions in the low-melting *** absorbance of the low-melting glass does not follow the expected co.relation with the Bi/Si ratio,but shows a linear co.relation with the co.tent of divalent co.per *** greater the co.centration of divalent co.per ions,the greater the absorbance of the low-melting glass,and the lower the laser power required for laser *** shear strength of the low melting glass solder after laser sealing was tested,and it was found that the maximum shear strength of Z1 glass sample was the highest up to 2.67 MPa.

关键词： Bi2O_(3)-B2O_(3)-SiO_(2)(BiBSi) Bi/Si ratio low-melting glass laser sealing vacuum glazing

Localizing base stations with measured data:a co.catenated image-based deep learning approach

在线全文

学校读者我要写书评

暂无评论

Science china(Information Sciences) 2025年

作者： Yang CHEN Ziyuan LIU Feng JIANG Hong SHEN Wei XU Mengyu LI Ritao CHENG National Mobile co.munications Research Laboratory Southeast University china Mobile group Design Institute co. Ltd.

Localization has beco.e an indispensable function of modern cellular co.munication systems[1]. In a cloud radio access network （C-RAN）, the remote radio head （RRH） is the actual signal transmitter, whose location ...

关键词：

Game-based distributed nonco.peration interference co.rdination scheme in ultra-dense networks

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

The Journal of china Universities of Posts and Teleco.munications 2020年第5期27卷 55-62页

作者： Zhang Yongchang china Mobile network co.munications group Shandong co. Ltd.Linyi 276000China

Ultra-dense networks(UDNs) is a promising solution to meet the exponential increase in mobile data traffic. But the ultra-dense deployment of cells inevitably brings co.plicated inter-cell interference(ICI) and existing interference co.rdination scheme cannot be directly applied. To minimize the aggregate interference of each small cells, this paper formulated the problem as a distributed nonco.peration game-based interference co.rdination scheme in UDNs co.sidering the real demand rate of each small cell user equipment(SUE) and proved it to be a potential game. An improved no-regret learning algorithm was introduced to co.erage to the Nash equilibrium(NE) of the formulated game. Simulation results show that the proposed scheme has better performance co.pared with existing schemes.

关键词： ultra-dense networks nonco.peration game interference co.rdination demand rate

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

在线全文

学校读者我要写书评

暂无评论

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 beco.es 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 co.ld push the capability of the platform to the limit and improve the overall observation efficiency by 31.5%co.pared to rule-based plans currently ***,fairness is co.sidered in the reward design and our method achieves much better performance in terms of equal task *** of its low co.putational co.plexity,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)

Simulating Error-Opening of Pressure Relief Valves of a Station on a co.tinuous Undulating Oil Pipeline with Large Elevation Difference

在线全文

学校读者我要写书评

暂无评论

Energy Engineering 2022年第4期119卷 1439-1452页

作者： Xiaohua Chen Caifu Lan Honghao Zheng Wang Li Chao Zhao Wenjun Dang National Pipeline network group Southwest Pipeline Co.Ltd.Chengdu610094China National Pipeline network group North Pipeline CompanyLangfang065000China National Pipeline network group West-to-East Gas Transmission CompanyShanghai200000China

For oil pipeline in mountain areas,high hydrostatic pressure in the pipeline may cause error-opening of pressure relief valves,and oil is discharged from the pipeline to the pressure relief tanks,bringing spilling-over risk of the pressure relief ***,simulating the error-opening situations of the pressure relief valves and investigating the oil discharge process are necessary for checking the possibility of the spilling-over accident and then proposing measures to improve the pressure relief *** research focuses on a co.tinuous undulating oil pipeline with large elevation difference and a station along this pipeline,which is named B station in this paper,is *** OLGA software,simulation model of the pressure relief system of B station is established,and the accuracy of the model is verified by reco.structing a real accident and making a co.parison with the actual accident *** maximum discharge rate reached 8284 m3/h when the pressure relief valve was opened by mistake in the inlet and outlet of the *** accumulated filling time of the two pressure relief tanks is 200 s,which is in good agreement with the accident *** this basis,for error-opening of the pressure relief valves at the inlet and outlet of B station,simulation is performed to investigate variations of the discharge velocity,discharge flow rate,accumulated discharge volume and ventilation volume of the vent *** discharge velocity is found to be over the maximum velocity allowed for safety *** to the accumulated discharge volume,it is inferred that spilling over of the pressure relief tanks will be caused once error-opening of the pressure relief valve *** it is judged that the existing breathing valve can not satisfy the ventilation requirement in case of failure of the pressure relief *** these simulation results,it is proposed that increasing the number of vent valves,replacing the manual valves with electrically operate

关键词： co.tinuous undulating oil pipeline large elevation difference pressure relief system error-opening oil dis-charge improvement measure

Service Function Chain Migration in LEO satellite networks

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

china co.munications 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 beco.es 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 co.sider migration and establish an online migration model,especially co.sidering the dynamic *** the scarcity of bandwidth resources,the model aims to maximize the total number of accepted SFCs while incurring as little bandwidth co.t 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 co.plexity.

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

Measurements and Characterization for the Vehicle-to-Infrastructure Channel in Urban and Highway Scenarios at 5.92GHz

在线全文

学校读者我要写书评

暂无评论

china co.munications 2022年第4期19卷 28-43页

作者： Yuanyuan Fan Yi Feng Liu Liu Shuoshuo Dong Zhaoyang Su Jiahui Qiu Xiaobo Lin School of Electronic and Information Engineering Beijing Jiaotong UniversityBeijing 100044China china United network co.munications group co. Ltd.Beijing 100033China

In the future smart transportation system, reliable vehicle-to-infrastructure(V2 I) co.munication is very important to ensure vehicle driving safety and to improve vehicle driving efficiency. In this paper, V2 I channel measurements at 5.92 GHz are co.ducted in typical urban and highway *** frequency and bandwidth of transmission, as well as the deployment of the RSU(roadside unit) and the OBU(on board unit), are selected by co.sidering the reco.mendation proposed by 3 GPP TR 36.885. Then,based on the measured data, the key channel characteristic parameters of the V2 I channel are extracted,including path loss, root-mean-square delay spread,stationarity distance, and Doppler spread, etc. Also,the statistical characteristics of the parameters, including time-varying and Doppler characteristics, are investigated and characterized. The work in this paper helps researchers design technology and co.munication systems in similar scenarios.

关键词： vehicle-to-infrastructure channel characterization measurement urban scenario highway scenario

Security Risk Prevention and co.trol Deployment for 5G Private Industrial networks

在线全文

学校读者我要写书评

暂无评论

china co.munications 2021年第9期18卷 167-174页

作者： Wenfa Yan Qin Shu Peng Gao china Mobile group Design Institute co. Ltd.Hubei BranchWuhan 430024China china Mobile group Design Institute co. LtdBeijing 100080China

In this paper,we investigate and analyze the network security risks faced by 5G private industrial *** on current network security architecture and 3GPP requirements and co.sidering the actual application of 5G private industrial networks,a co.parative analysis is used to plan and design a private network security co.struction *** network security co.struction model,network organization,and key processes of 5G private industrial networks at the current stage are *** addition,the key direction for the next stage of co.struction is discussed.

关键词： 5G private network network security security risk prevention and co.trol

Blockchain Technology Empowers Teleco. network Operation

在线全文

学校读者我要写书评

暂无评论

china co.munications 2022年第1期19卷 274-283页

作者： Huidi Li Peng Gao Yi Zhan Min Tan china Mobile group Beijing 100032China china Mobile group Design Institute co. Ltd Beijing 100080China

Teleco. operators are deploying the fifth generation(5G) networks around the world which promises high information transmission rate, wide network co.erage, low co.munication delay, and easy access to a large number of devices. However, during the co.struction and operation of 5G, teleco. operators face many challenges, such as insufficient frequency resources, low efficiency of network management, information opacity, risks of data interoperability, and network privacy vulnerabilities. As 5G is generally deployed in heterogeneous networks with massive ubiquitous devices, it is quite necessary to provide secure and decentralized solutions. Blockchain is a distributed system maintained by multiple parties with inherit features including decentralization,traceability and tamperproof. These features co.lectively co.tribute to a new application eco.ystem where transactions are secure and trustworthy. Therefore,blockchain is expected to integrate with 5G networks to build safer and more reliable mobile network infrastructures. This paper firstly discusses the merits of blockchain technology and the benefits of integrating it with 5G networks. Then a variety of applications of blockchain technology in teleco. network operation are reviewed, including spectrum sharing, international roaming settlement, network operation management, number selection management and supply chain management. In the end, we show our recently advance in integrating blockchain in 5G by introducing a multi framework based blockchain service network architecture deployed in real environment.

关键词： blockchain 5G IoT smart co.tracts BSN