Reliable communication and intensive computing power cannot be provided effectively by temporary hot spots in disaster areas and complex terrain ground infrastructure.Mitigating this has greatly developed the applicat...Reliable communication and intensive computing power cannot be provided effectively by temporary hot spots in disaster areas and complex terrain ground infrastructure.Mitigating this has greatly developed the application and integration of UAV and Mobile Edge Computing(MEC)to the Internet of Things(loT).However,problems such as multi-user and huge data flow in large areas,which contradict the reality that a single UAV is constrained by limited computing power,still exist.Due to allowing UAV collaboration to accomplish complex tasks,cooperative task offloading between multiple UAVs must meet the interdependence of tasks and realize parallel processing,which reduces the computing power consumption and endurance pressure of terminals.Considering the computing requirements of the user terminal,delay constraint of a computing task,energy constraint,and safe distance of UAV,we constructed a UAV-Assisted cooperative offloading energy efficiency system for mobile edge computing to minimize user terminal energy consumption.However,the resulting optimization problem is originally nonconvex and thus,difficult to solve optimally.To tackle this problem,we developed an energy efficiency optimization algorithm using Block Coordinate Descent(BCD)that decomposes the problem into three convex subproblems.Furthermore,we jointly optimized the number of local computing tasks,number of computing offloaded tasks,trajectories of UAV,and offloading matching relationship between multi-UAVs and multiuser terminals.Simulation results show that the proposed approach is suitable for different channel conditions and significantly saves the user terminal energy consumption compared with other benchmark schemes.展开更多
西尼罗病毒(West Nile virus,WNV)是重要的虫媒病毒之一。美国自1999年首次在纽约市发现WNV以来,在WNV感染风险监测和管理方面进行了大量的研究和实践。建立的以蚊子、鸟类为基础的环境监测系统,不仅起到了对WNV感染早期预警的关键作用...西尼罗病毒(West Nile virus,WNV)是重要的虫媒病毒之一。美国自1999年首次在纽约市发现WNV以来,在WNV感染风险监测和管理方面进行了大量的研究和实践。建立的以蚊子、鸟类为基础的环境监测系统,不仅起到了对WNV感染早期预警的关键作用,同时还为下一步制定防控措施提供了依据;采取的虫媒综合管理和分阶段风险响应管理等措施,成功控制了WNV的传染源和传播途径,为减轻其对公共卫生的影响起到了关键作用。本文介绍了美国WNV流行情况、风险监测方法及风险管理措施,以期对我国WNV感染等虫媒传播人兽共患病的流行病学研究、早期预警、口岸风险分析以及科学防控提供依据。展开更多
基金supported by the Jiangsu Provincial Key Research and Development Program(No.BE2020084-4)the National Natural Science Foundation of China(No.92067201)+2 种基金the National Natural Science Foundation of China(61871446)the Open Research Fund of Jiangsu Key Laboratory of Wireless Communications(710020017002)the Natural Science Foundation of Nanjing University of Posts and telecommunications(NY220047).
文摘Reliable communication and intensive computing power cannot be provided effectively by temporary hot spots in disaster areas and complex terrain ground infrastructure.Mitigating this has greatly developed the application and integration of UAV and Mobile Edge Computing(MEC)to the Internet of Things(loT).However,problems such as multi-user and huge data flow in large areas,which contradict the reality that a single UAV is constrained by limited computing power,still exist.Due to allowing UAV collaboration to accomplish complex tasks,cooperative task offloading between multiple UAVs must meet the interdependence of tasks and realize parallel processing,which reduces the computing power consumption and endurance pressure of terminals.Considering the computing requirements of the user terminal,delay constraint of a computing task,energy constraint,and safe distance of UAV,we constructed a UAV-Assisted cooperative offloading energy efficiency system for mobile edge computing to minimize user terminal energy consumption.However,the resulting optimization problem is originally nonconvex and thus,difficult to solve optimally.To tackle this problem,we developed an energy efficiency optimization algorithm using Block Coordinate Descent(BCD)that decomposes the problem into three convex subproblems.Furthermore,we jointly optimized the number of local computing tasks,number of computing offloaded tasks,trajectories of UAV,and offloading matching relationship between multi-UAVs and multiuser terminals.Simulation results show that the proposed approach is suitable for different channel conditions and significantly saves the user terminal energy consumption compared with other benchmark schemes.
文摘西尼罗病毒(West Nile virus,WNV)是重要的虫媒病毒之一。美国自1999年首次在纽约市发现WNV以来,在WNV感染风险监测和管理方面进行了大量的研究和实践。建立的以蚊子、鸟类为基础的环境监测系统,不仅起到了对WNV感染早期预警的关键作用,同时还为下一步制定防控措施提供了依据;采取的虫媒综合管理和分阶段风险响应管理等措施,成功控制了WNV的传染源和传播途径,为减轻其对公共卫生的影响起到了关键作用。本文介绍了美国WNV流行情况、风险监测方法及风险管理措施,以期对我国WNV感染等虫媒传播人兽共患病的流行病学研究、早期预警、口岸风险分析以及科学防控提供依据。
