This paper investigates an unmanned aerial vehicle(UAV)-assisted multi-object offloading scheme for blockchain-enabled Vehicle-to-Everything(V2X)systems.Due to the presence of an eavesdropper(Eve),the system’s com-mu...This paper investigates an unmanned aerial vehicle(UAV)-assisted multi-object offloading scheme for blockchain-enabled Vehicle-to-Everything(V2X)systems.Due to the presence of an eavesdropper(Eve),the system’s com-munication links may be insecure.This paper proposes deploying an intelligent reflecting surface(IRS)on the UAV to enhance the communication performance of mobile vehicles,improve system flexibility,and alleviate eavesdropping on communication links.The links for uploading task data from vehicles to a base station(BS)are protected by IRS-assisted physical layer security(PLS).Upon receiving task data,the computing resources provided by the edge computing servers(MEC)are allocated to vehicles for task execution.Existing blockchain-based computation offloading schemes typically focus on improving network performance,such as minimizing energy consumption or latency,while neglecting the Gas fees for computation offloading and the costs required for MEC computation,leading to an imbalance between service fees and resource allocation.This paper uses a utility-oriented computation offloading scheme to balance costs and resources.This paper proposes alternating phase optimization and power optimization to optimize the energy consumption,latency,and communication secrecy rate,thereby maximizing the weighted total utility of the system.Simulation results demonstrate a notable enhancement in the weighted total system utility and resource utilization,thereby corroborating the viability of our approach for practical applications.展开更多
In blockchain-based unmanned aerial vehicle(UAV)communication systems,the length of a block affects the performance of the blockchain.The transmission performance of blocks in the form of finite character segments is ...In blockchain-based unmanned aerial vehicle(UAV)communication systems,the length of a block affects the performance of the blockchain.The transmission performance of blocks in the form of finite character segments is also affected by the block length.Therefore,it is crucial to balance the transmission performance and blockchain performance of blockchain communication systems,especially in wireless environments involving UAVs.This paper investigates a secure transmission scheme for blocks in blockchain-based UAV communication systems to prevent the information contained in blocks from being completely eavesdropped during transmission.In our scheme,using a friendly jamming UAV to emit jamming signals diminishes the quality of the eavesdropping channel,thus enhancing the communication security performance of the source UAV.Under the constraints of maneuverability and transmission power of the UAV,the joint design of UAV trajectories,transmission power,and block length are proposed to maximize the average minimum secrecy rate(AMSR).Since the optimization problem is non-convex and difficult to solve directly,we first decompose the optimization problem into subproblems of trajectory optimization,transmission power optimization,and block length optimization.Then,based on firstorder approximation techniques,these subproblems are reformulated as convex optimization problems.Finally,we utilize an alternating iteration algorithm based on the successive convex approximation(SCA)technique to solve these subproblems iteratively.The simulation results demonstrate that our proposed scheme can achieve secure transmission for blocks while maintaining the performance of the blockchain.展开更多
目的:评价沙美特罗替卡松联合孟鲁司特治疗咳嗽变异性哮喘的疗效和安全性,为临床提供循证参考。方法:计算机检索Cochrane图书馆、Pub Med、中国期刊全文数据库、中文科技期刊数据库、万方数据库,纳入沙美特罗替卡松联合孟鲁司特(试验组...目的:评价沙美特罗替卡松联合孟鲁司特治疗咳嗽变异性哮喘的疗效和安全性,为临床提供循证参考。方法:计算机检索Cochrane图书馆、Pub Med、中国期刊全文数据库、中文科技期刊数据库、万方数据库,纳入沙美特罗替卡松联合孟鲁司特(试验组)对比沙美特罗替卡松(对照组)治疗咳嗽变异性哮喘疗效(总有效率和显效率、咳嗽消失时间、6~12个月复发率)与安全性(不良反应发生率)的随机对照试验(RCT),提取资料并采用Cochrane系统评价手册5.1.0进行质量评价后,采用Rev Man 5.3软件进行Meta分析。结果:共纳入10项RCT,合计976例患者。Meta分析结果显示,试验组患者总有效率[RR=1.22,95%CI(1.16,1.29),P<0.001]、显效率[RR=1.38,95%CI(1.22,1.56),P<0.001]显著高于对照组,咳嗽消失时间显著短于对照组[MD=-3.07,95%CI(-3.54,-2.59),P<0.001],6~12个月复发率显著低于对照组[RR=0.24,95%CI(0.11,0.54),P<0.001],以上差异均有统计学意义;两组患者不良反应发生率比较差异无统计学意义[RR=1.58,95%CI(0.99,2.51),P=0.05]。结论:沙美特罗替卡松联合孟鲁司特对比沙美特罗替卡松单用治疗咳嗽变异性哮喘疗效更好,但联合用药时应注意不良事件的发生。展开更多
基金supported in part by the National Key R&D Program of China under Grant 2022YFB3104503in part by the China Postdoctoral Science Foundation under Grant 2024M750199+1 种基金in part by the National Natural Science Foundation of China under Grant 62202054,Grant 62002022 and Grant 62472251in part by the Fundamental Research Funds for the Central Universities under Grant BLX202360.
文摘This paper investigates an unmanned aerial vehicle(UAV)-assisted multi-object offloading scheme for blockchain-enabled Vehicle-to-Everything(V2X)systems.Due to the presence of an eavesdropper(Eve),the system’s com-munication links may be insecure.This paper proposes deploying an intelligent reflecting surface(IRS)on the UAV to enhance the communication performance of mobile vehicles,improve system flexibility,and alleviate eavesdropping on communication links.The links for uploading task data from vehicles to a base station(BS)are protected by IRS-assisted physical layer security(PLS).Upon receiving task data,the computing resources provided by the edge computing servers(MEC)are allocated to vehicles for task execution.Existing blockchain-based computation offloading schemes typically focus on improving network performance,such as minimizing energy consumption or latency,while neglecting the Gas fees for computation offloading and the costs required for MEC computation,leading to an imbalance between service fees and resource allocation.This paper uses a utility-oriented computation offloading scheme to balance costs and resources.This paper proposes alternating phase optimization and power optimization to optimize the energy consumption,latency,and communication secrecy rate,thereby maximizing the weighted total utility of the system.Simulation results demonstrate a notable enhancement in the weighted total system utility and resource utilization,thereby corroborating the viability of our approach for practical applications.
基金supported in part by the National Key R&D Program of China under Grant 2022YFB3104503in part by the China Postdoctoral Science Foundation under Grant 2024M750199+1 种基金in part by the National Natural Science Foundation of China under Grants 62202054,62002022 and 62472251in part by the Fundamental Research Funds for the Central Universities under Grant BLX202360.
文摘In blockchain-based unmanned aerial vehicle(UAV)communication systems,the length of a block affects the performance of the blockchain.The transmission performance of blocks in the form of finite character segments is also affected by the block length.Therefore,it is crucial to balance the transmission performance and blockchain performance of blockchain communication systems,especially in wireless environments involving UAVs.This paper investigates a secure transmission scheme for blocks in blockchain-based UAV communication systems to prevent the information contained in blocks from being completely eavesdropped during transmission.In our scheme,using a friendly jamming UAV to emit jamming signals diminishes the quality of the eavesdropping channel,thus enhancing the communication security performance of the source UAV.Under the constraints of maneuverability and transmission power of the UAV,the joint design of UAV trajectories,transmission power,and block length are proposed to maximize the average minimum secrecy rate(AMSR).Since the optimization problem is non-convex and difficult to solve directly,we first decompose the optimization problem into subproblems of trajectory optimization,transmission power optimization,and block length optimization.Then,based on firstorder approximation techniques,these subproblems are reformulated as convex optimization problems.Finally,we utilize an alternating iteration algorithm based on the successive convex approximation(SCA)technique to solve these subproblems iteratively.The simulation results demonstrate that our proposed scheme can achieve secure transmission for blocks while maintaining the performance of the blockchain.
文摘目的:评价沙美特罗替卡松联合孟鲁司特治疗咳嗽变异性哮喘的疗效和安全性,为临床提供循证参考。方法:计算机检索Cochrane图书馆、Pub Med、中国期刊全文数据库、中文科技期刊数据库、万方数据库,纳入沙美特罗替卡松联合孟鲁司特(试验组)对比沙美特罗替卡松(对照组)治疗咳嗽变异性哮喘疗效(总有效率和显效率、咳嗽消失时间、6~12个月复发率)与安全性(不良反应发生率)的随机对照试验(RCT),提取资料并采用Cochrane系统评价手册5.1.0进行质量评价后,采用Rev Man 5.3软件进行Meta分析。结果:共纳入10项RCT,合计976例患者。Meta分析结果显示,试验组患者总有效率[RR=1.22,95%CI(1.16,1.29),P<0.001]、显效率[RR=1.38,95%CI(1.22,1.56),P<0.001]显著高于对照组,咳嗽消失时间显著短于对照组[MD=-3.07,95%CI(-3.54,-2.59),P<0.001],6~12个月复发率显著低于对照组[RR=0.24,95%CI(0.11,0.54),P<0.001],以上差异均有统计学意义;两组患者不良反应发生率比较差异无统计学意义[RR=1.58,95%CI(0.99,2.51),P=0.05]。结论:沙美特罗替卡松联合孟鲁司特对比沙美特罗替卡松单用治疗咳嗽变异性哮喘疗效更好,但联合用药时应注意不良事件的发生。
