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High Stable and Accurate Vehicle Selection Scheme Based on Federated Edge Learning in Vehicular Networks 被引量:2
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作者 Qiong Wu Xiaobo Wang +3 位作者 Qiang Fan Pingyi Fan Cui Zhang Zhengquan Li 《China Communications》 SCIE CSCD 2023年第3期1-17,共17页
Federated edge learning(FEEL)technology for vehicular networks is considered as a promising technology to reduce the computation workload while keeping the privacy of users.In the FEEL system,vehicles upload data to t... Federated edge learning(FEEL)technology for vehicular networks is considered as a promising technology to reduce the computation workload while keeping the privacy of users.In the FEEL system,vehicles upload data to the edge servers,which train the vehicles’data to update local models and then return the result to vehicles to avoid sharing the original data.However,the cache queue in the edge is limited and the channel between edge server and each vehicle is time-varying.Thus,it is challenging to select a suitable number of vehicles to ensure that the uploaded data can keep a stable cache queue in edge server while maximizing the learning accuracy.Moreover,selecting vehicles with different resource statuses to update data will affect the total amount of data involved in training,which further affects the model accuracy.In this paper,we propose a vehicle selection scheme,which maximizes the learning accuracy while ensuring the stability of the cache queue,where the statuses of all the vehicles in the coverage of edge server are taken into account.The performance of this scheme is evaluated through simulation experiments,which indicates that our proposed scheme can perform better than the known benchmark scheme. 展开更多
关键词 FEEL stability ACCURACY vehicular net-works edge servers
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Performance analysis and comparison of PoW,PoS and DAG based blockchains 被引量:22
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作者 Bin Cao Zhenghui Zhang +4 位作者 Daquan Feng Shengli Zhang Lei Zhang Mugen Peng Yun Li 《Digital Communications and Networks》 SCIE 2020年第4期480-485,共6页
In the blockchain,the consensus mechanism plays a key role in maintaining the security and legitimation of contents recorded in the blocks.Various blockchain consensus mechanisms have been proposed.However,there is no... In the blockchain,the consensus mechanism plays a key role in maintaining the security and legitimation of contents recorded in the blocks.Various blockchain consensus mechanisms have been proposed.However,there is no technical analysis and comparison as a guideline to determine which type of consensus mechanism should be adopted in a specific scenario/application.To this end,this work investigates three mainstream consensus mechanisms in the blockchain,namely,Proof of Work(PoW),Proof of Stake(PoS),and Direct Acyclic Graph(DAG),and identifies their performances in terms of the average time to generate a new block,the confirmation delay,the Transaction Per Second(TPS)and the confirmation failure probability.The results show that the consensus process is affected by both network resource(computation power/coin age,buffer size)and network load conditions.In addition,it shows that PoW and PoS are more sensitive to the change of network resource while DAG is more sensitive to network load conditions. 展开更多
关键词 Blockchain Proof of work Proof of stake Direct acyclic graph Performance comparison
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Interference management via access control and mobility prediction in two-tier heterogeneous networks 被引量:1
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作者 肖竹 陈杰 +2 位作者 王东 李仁发 易克初 《Journal of Central South University》 SCIE EI CAS 2014年第8期3169-3177,共9页
Abstract: Two-tier heterogeneous networks (HetNets), where the current cellular networks, i.e., macrocells, are overlapped with a large number of randomly distributed femtocells, can potentially bring significant b... Abstract: Two-tier heterogeneous networks (HetNets), where the current cellular networks, i.e., macrocells, are overlapped with a large number of randomly distributed femtocells, can potentially bring significant benefits to spectral utilization and system capacity. The interference management and access control for open and closed femtocells in two-tier HetNets were focused. The contributions consist of two parts. Firstly, in order to reduce the uplink interference caused by MUEs (macrocell user equipments) at closed femtocells, an incentive mechanism to implement interference mitigation was proposed. It encourages femtoeells that work with closed-subscriber-group (CSG) to allow the interfering MUEs access in but only via uplink, which can reduce the interference significantly and also benefit the marco-tier. The interference issue was then studied in open-subscriber-group (OSG) femtocells from the perspective of handover and mobility prediction. Inbound handover provides an alternative solution for open femtocells when interference turns up, while this accompanies with PCI (physical cell identity) confusion during inbound handover. To reduce the PCI confusion, a dynamic PCI allocation scheme was proposed, by which the high handin femtocells have the dedicated PCI while the others share the reuse PCIs. A Markov chain based mobility prediction algorithm was designed to decide whether the femtoeell status is with high handover requests. Numerical analysis reveals that the UL interference is managed well for the CSG femtocell and the PCI confusion issue is mitigated greatly in OSG femtocell compared to the conventional approaches. 展开更多
关键词 FEMTOCELL MACROCELL interference management heterogeneous networks access control HANDOVER mobility prediction
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Particle filter with importance density function generated by updated system equation 被引量:3
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作者 左军毅 贾颖娜 +1 位作者 张炜 高全学 《Journal of Central South University》 SCIE EI CAS 2013年第10期2700-2707,共8页
The current measurement was exploited in a more efficient way. Firstly, the system equation was updated by introducing a correction term, which depends on the current measurement and can be obtained by running a subop... The current measurement was exploited in a more efficient way. Firstly, the system equation was updated by introducing a correction term, which depends on the current measurement and can be obtained by running a suboptimal filter. Then, a new importance density function(IDF) was defined by the updated system equation. Particles drawn from the new IDF are more likely to be in the significant region of state space and the estimation accuracy can be improved. By using different suboptimal filter, different particle filters(PFs) can be developed in this framework. Extensions of this idea were also proposed by iteratively updating the system equation using particle filter itself, resulting in the iterated particle filter. Simulation results demonstrate the effectiveness of the proposed IDF. 展开更多
关键词 IMPORTANCE density function nonlinear dynamic systems SEQUENCE IMPORTANCE sampling particle filter MONTE Carlo STEP
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Critical safe distance design to improve driving safety based on vehicle-to-vehicle communications 被引量:5
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作者 陈晨 吕宁 +2 位作者 刘雷 裴庆祺 李晓记 《Journal of Central South University》 SCIE EI CAS 2013年第11期3334-3344,共11页
A critical safe distance(CSD)model in V2V(vehicle-to-vehicle)communication systems was proposed to primarily enhance driving safety by disseminating warning notifications to vehicles when they approach calculated CSD.... A critical safe distance(CSD)model in V2V(vehicle-to-vehicle)communication systems was proposed to primarily enhance driving safety by disseminating warning notifications to vehicles when they approach calculated CSD.By elaborately analyzing the vehicular movement features especially when braking,our CSD definition was introduced and its configuration method was given through dividing radio range into different communication zones.Based on our definition,the needed message propagation delay was also derived which could be used to control the beacon frequency or duration.Next,the detailed CSD expressions were proposed in different mobility scenarios by fully considering the relative movement status between the front and rear vehicles.Numerical results show that our proposed model could provide reasonable CSD under different movement scenarios which eliminates the unnecessary reserved inter-vehicle distance and guarantee the safety at the same time.The compared time-headway model always shows a smaller CSD due to focusing on traffic efficiency whereas the traditional braking model generally outputs a larger CSD because it assumes that the following car drives with a constant speed and did not discuss the scenario when the leading car suddenly stops.Different from these two models,our proposed model could well balances the requirements between driving safety and traffic throughput efficiency by generating a CSD in between the values of the two models in most cases. 展开更多
关键词 vehicle-to-vehicle communication systems collsion avoidance saftey distance
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A quantum secure direct communication scheme based on intermediate-basis 被引量:1
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作者 Kexin Liang Zhengwen Cao +3 位作者 Xinlei Chen Lei Wang Geng Chai Jinye Peng 《Frontiers of physics》 SCIE CSCD 2023年第5期321-329,共9页
Quantum secure direct communication(QSDC)is a method of communication that transmits secret information directly through a quantum channel.This paper proposes a two-step QSDC scheme based on intermediate-basis,in whic... Quantum secure direct communication(QSDC)is a method of communication that transmits secret information directly through a quantum channel.This paper proposes a two-step QSDC scheme based on intermediate-basis,in which the intermediate-basis Einstein–Podolsky–Rosen(EPR)pairs can assist to detect channel security and help encode information.Specifically,the intermediate-basis EPR pairs reduce the probability of Eve choosing the correct measurement basis in the first step,enhancing the security of the system.Moreover,they encode information together with information EPR pairs to improve the transmission efficiency in the second step.We consider the security of the protocol under coherent attack when Eve takes different dimensions of the auxiliary system.The simulation results show that intermediate-basis EPR pairs can lower the upper limit of the amount of information that Eve can steal in both attack scenarios.Therefore,the proposed protocol can ensure that the legitimate parties get more confidential information and improve the transmission efficiency. 展开更多
关键词 quantum secure direct communication TWO-STEP intermediate-basis
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Fully distributed identity-based threshold signatures with identifiable aborts
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作者 Yan JIANG Youwen ZHU +1 位作者 Jian WANG Xingxin LI 《Frontiers of Computer Science》 SCIE EI CSCD 2023年第5期179-195,共17页
Identity-based threshold signature(IDTS)is a forceful primitive to protect identity and data privacy,in which parties can collaboratively sign a given message as a signer without reconstructing a signing key.Neverthel... Identity-based threshold signature(IDTS)is a forceful primitive to protect identity and data privacy,in which parties can collaboratively sign a given message as a signer without reconstructing a signing key.Nevertheless,most IDTS schemes rely on a trusted key generation center(KGC).Recently,some IDTS schemes can achieve escrow-free security against corrupted KGC,but all of them are vulnerable to denial-of-service attacks in the dishonest majority setting,where cheaters may force the protocol to abort without providing any feedback.In this work,we present a fully decentralized IDTS scheme to resist corrupted KGC and denialof-service attacks.To this end,we design threshold protocols to achieve distributed key generation,private key extraction,and signing generation which can withstand the collusion between KGCs and signers,and then we propose an identification mechanism that can detect the identity of cheaters during key generation,private key extraction and signing generation.Finally,we formally prove that the proposed scheme is threshold unforgeability against chosen message attacks.The experimental results show that the computation time of both key generation and signing generation is<1 s,and private key extraction is about 3 s,which is practical in the distributed environment. 展开更多
关键词 threshold signatures single points of failure identifiable aborts
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