Wireless Sensor Network(WSN)is a cornerstone of Internet of Things(IoT)and has rich application scenarios.In this work,we consider a heterogeneous WSN whose sensor nodes have a diversity in their Residual Energy(RE).I...Wireless Sensor Network(WSN)is a cornerstone of Internet of Things(IoT)and has rich application scenarios.In this work,we consider a heterogeneous WSN whose sensor nodes have a diversity in their Residual Energy(RE).In this work,to protect the sensor nodes with low RE,we investigate dynamic working modes for sensor nodes which are determined by their RE and an introduced energy threshold.Besides,we employ an Unmanned Aerial Vehicle(UAV)to collect the stored data from the heterogeneous WSN.We aim to jointly optimize the cluster head selection,energy threshold and sensor nodes’working mode to minimize the weighted sum of energy con-sumption from the WSN and UAV,subject to the data collection rate constraint.To this end,we propose an efficient search method to search for an optimal energy threshold,and develop a penalty-based successive convex approximation algorithm to select the cluster heads.Then we present a low-complexity iterative approach to solve the joint optimization problem and discuss the implementation procedure.Numerical results justify that our proposed approach is able to reduce the energy consumption of the sensor nodes with low RE significantly and also saves energy for the whole WSN.展开更多
In recent years,unmanned aerial vehicles(UAVs)for plant protection have achieved rapid development in China.In order to test and evaluate the performances of pesticides application and development status of UAVs in Ch...In recent years,unmanned aerial vehicles(UAVs)for plant protection have achieved rapid development in China.In order to test and evaluate the performances of pesticides application and development status of UAVs in China,four typical UAV models were selected to test the spraying coverage,penetrability,droplets density and the work efficiency.The results showed that the deposition and spraying liquid coverage were inconsistent both in lateral and longitudinal direction.Under the condition of the similar amount of spray volume and operation parameters,the volume median diameter(VMD)of the droplet was negatively correlated with the coverage density.The failure of the UAVs for plant protection mainly took up on the blockage of nozzle,transfusion tube and the liquid pump.The failure rate of UAVs took up 3.73%-4.36%of the total working time.The operation of UAVs during ground service took up 50%of the total working time,the preparation work took up 10%,and the route planning took up around 10%,while net operation time only took up around 30%.On the whole,the high efficiency of UAV was not fully achieved;the daily operated area was not in a satisfactory level now.The spraying performances of UAVs still need further improvement.展开更多
为了给500 k V带电作业用绝缘斗臂车的安全使用提供技术依据,通过试验研究确定了绝缘斗臂车带电作业的安全距离。首先结合实际线路和车辆,针对使用绝缘斗臂车在500 k V单回线路直线塔进行带电作业时的各典型工作位置的安全距离进行了1:...为了给500 k V带电作业用绝缘斗臂车的安全使用提供技术依据,通过试验研究确定了绝缘斗臂车带电作业的安全距离。首先结合实际线路和车辆,针对使用绝缘斗臂车在500 k V单回线路直线塔进行带电作业时的各典型工作位置的安全距离进行了1:1模拟工况的操作冲击放电试验研究。结果表明,作为大型导电悬浮体的工作斗降低了组合间隙的击穿电压约15%。依据试验结果,通过危险率计算分析确定了海拔1 000 m地区500 k V绝缘斗臂车带电作业的中相最小安全距离和组合间隙分别为3.8 m和4.7 m,边相最小安全距离和组合间隙分别为3.2 m和3.8 m。考虑到工作斗的长度和导线距塔身的间隙,当工作斗的位于导线和塔身的间隙之中时,安全距离和组合间隙难以满足要求。因此当使用绝缘斗臂车在500 k V直线杆塔上开展带电作业时,工作斗不应进入边相导线和杆塔之间以及中相塔窗。展开更多
基金supported in part by the National Nature Science Foundation of China under Grant 62001168in part by the Foundation and Application Research Grant of Guangzhou under Grant 202102020515.
文摘Wireless Sensor Network(WSN)is a cornerstone of Internet of Things(IoT)and has rich application scenarios.In this work,we consider a heterogeneous WSN whose sensor nodes have a diversity in their Residual Energy(RE).In this work,to protect the sensor nodes with low RE,we investigate dynamic working modes for sensor nodes which are determined by their RE and an introduced energy threshold.Besides,we employ an Unmanned Aerial Vehicle(UAV)to collect the stored data from the heterogeneous WSN.We aim to jointly optimize the cluster head selection,energy threshold and sensor nodes’working mode to minimize the weighted sum of energy con-sumption from the WSN and UAV,subject to the data collection rate constraint.To this end,we propose an efficient search method to search for an optimal energy threshold,and develop a penalty-based successive convex approximation algorithm to select the cluster heads.Then we present a low-complexity iterative approach to solve the joint optimization problem and discuss the implementation procedure.Numerical results justify that our proposed approach is able to reduce the energy consumption of the sensor nodes with low RE significantly and also saves energy for the whole WSN.
基金supported by the Special Fund for Agro-scientific Research in the Public Interest(201503130)the National Key Research and Development Plan(Grant No.2016YFD0200700)+1 种基金National Science Fund Projects(31470099)Beijing Science and Technology Plan Projects(No.D171100002317003).
文摘In recent years,unmanned aerial vehicles(UAVs)for plant protection have achieved rapid development in China.In order to test and evaluate the performances of pesticides application and development status of UAVs in China,four typical UAV models were selected to test the spraying coverage,penetrability,droplets density and the work efficiency.The results showed that the deposition and spraying liquid coverage were inconsistent both in lateral and longitudinal direction.Under the condition of the similar amount of spray volume and operation parameters,the volume median diameter(VMD)of the droplet was negatively correlated with the coverage density.The failure of the UAVs for plant protection mainly took up on the blockage of nozzle,transfusion tube and the liquid pump.The failure rate of UAVs took up 3.73%-4.36%of the total working time.The operation of UAVs during ground service took up 50%of the total working time,the preparation work took up 10%,and the route planning took up around 10%,while net operation time only took up around 30%.On the whole,the high efficiency of UAV was not fully achieved;the daily operated area was not in a satisfactory level now.The spraying performances of UAVs still need further improvement.
文摘为了给500 k V带电作业用绝缘斗臂车的安全使用提供技术依据,通过试验研究确定了绝缘斗臂车带电作业的安全距离。首先结合实际线路和车辆,针对使用绝缘斗臂车在500 k V单回线路直线塔进行带电作业时的各典型工作位置的安全距离进行了1:1模拟工况的操作冲击放电试验研究。结果表明,作为大型导电悬浮体的工作斗降低了组合间隙的击穿电压约15%。依据试验结果,通过危险率计算分析确定了海拔1 000 m地区500 k V绝缘斗臂车带电作业的中相最小安全距离和组合间隙分别为3.8 m和4.7 m,边相最小安全距离和组合间隙分别为3.2 m和3.8 m。考虑到工作斗的长度和导线距塔身的间隙,当工作斗的位于导线和塔身的间隙之中时,安全距离和组合间隙难以满足要求。因此当使用绝缘斗臂车在500 k V直线杆塔上开展带电作业时,工作斗不应进入边相导线和杆塔之间以及中相塔窗。
