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
A more accurate analysis method on working modes is proposed by considering the winding terminal voltage and the eondueting power device as state parameters. For the three-phase hybrid excitation doubly salient machi...A more accurate analysis method on working modes is proposed by considering the winding terminal voltage and the eondueting power device as state parameters. For the three-phase hybrid excitation doubly salient machine （HEDSM） motor and its three-phase full-bridge inverter, in the proposed analytical method, all possible working modes are generally listed. Then, with the H_PWM-L_ON control strategy, the working modes are detailed with eorresponding equivalent circuits. Experimental results verify the robustness of the analysis.展开更多
From electric circuit theory view, a system model of series hybrid electric vehicle was built which uses engine-generator and battery pack as its on-board energy source in this paper. Based on the analysis for the con...From electric circuit theory view, a system model of series hybrid electric vehicle was built which uses engine-generator and battery pack as its on-board energy source in this paper. Based on the analysis for the constant power work mode and constant bus voltage work mode of engine-generator, a third work mode was put forward which combined the advantages of constant power and constant bus voltage work modes. The new work mode is reasonable to keep the battery in good working conditions and to extend its life. Also the working conditions of engine can be bettered to get low pollution and high efficiency.展开更多
The paper analyzes the practical use of management mode of small-scale farmland irrigation works in China,and studies various problems existing in the present management mode.It puts forward a mode named Water-consume...The paper analyzes the practical use of management mode of small-scale farmland irrigation works in China,and studies various problems existing in the present management mode.It puts forward a mode named Water-consumer Association which is the most practical one at present.It points out some rules which must be mastered in solving problems appearing in using this mode.展开更多
Project-based learning has been in widespread use in education. However, project managers are unaware of the students’ lack of experience and treat them as if they were professional staff. This paper proposes the app...Project-based learning has been in widespread use in education. However, project managers are unaware of the students’ lack of experience and treat them as if they were professional staff. This paper proposes the application of a fuzzy failure mode and effects analysis model for project-based software engineering education. This method integrates the fuzzy rule-based system with learning agents. The agents construct the membership function from historical data. Data are processed by a clustering process that facilitates the construction of the membership function. It helps students who lack experience in risk assessment to develop their expertise in that skill. The paper also suggests a classification technique for a fuzzy rule-based system that can be used to judge risk based on a fuzzy inference system. The student project will thus be further enhanced with respect to risk assessment. We then discuss the design of experiments to verify the proposed model.展开更多
As a power infrastructure directly facing power users, transmission line is the direct power source of end users. Therefore, the normal operation of transmission line is a key link to ensure high-quality power supply ...As a power infrastructure directly facing power users, transmission line is the direct power source of end users. Therefore, the normal operation of transmission line is a key link to ensure high-quality power supply service. Due to the wide range of transmission line erection, the erection site is mainly in urban areas with complex environment, and the insulation level is lower than the transmission network, resulting in high failure rate, heavy maintenance workload and more power outages caused by maintenance. In order to ensure the reliability demand of users, improve the satisfaction of users, and reduce the power failure caused by maintenance and fault, live working technology is proposed and applied to practical production. Live working is a kind of operation mode for inspection and maintenance under the condition of keeping all equipment of power grid without power failure. At present, most of the maintenance work and accident handling work in the transmission line can be completed under the condition of live operation. Therefore, the implementation of live operation can significantly reduce the power outage duration and power outage times of users and improve the reliability of power supply.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.
文摘A more accurate analysis method on working modes is proposed by considering the winding terminal voltage and the eondueting power device as state parameters. For the three-phase hybrid excitation doubly salient machine （HEDSM） motor and its three-phase full-bridge inverter, in the proposed analytical method, all possible working modes are generally listed. Then, with the H_PWM-L_ON control strategy, the working modes are detailed with eorresponding equivalent circuits. Experimental results verify the robustness of the analysis.
文摘From electric circuit theory view, a system model of series hybrid electric vehicle was built which uses engine-generator and battery pack as its on-board energy source in this paper. Based on the analysis for the constant power work mode and constant bus voltage work mode of engine-generator, a third work mode was put forward which combined the advantages of constant power and constant bus voltage work modes. The new work mode is reasonable to keep the battery in good working conditions and to extend its life. Also the working conditions of engine can be bettered to get low pollution and high efficiency.
基金Supported by Provincial Water Conservancy Research and Technology Promotion Project:Research on Key Technical Problems of Farmland Water Conservancy Projects in Shandong Province(SDSLKY201401)
文摘The paper analyzes the practical use of management mode of small-scale farmland irrigation works in China,and studies various problems existing in the present management mode.It puts forward a mode named Water-consumer Association which is the most practical one at present.It points out some rules which must be mastered in solving problems appearing in using this mode.
文摘Project-based learning has been in widespread use in education. However, project managers are unaware of the students’ lack of experience and treat them as if they were professional staff. This paper proposes the application of a fuzzy failure mode and effects analysis model for project-based software engineering education. This method integrates the fuzzy rule-based system with learning agents. The agents construct the membership function from historical data. Data are processed by a clustering process that facilitates the construction of the membership function. It helps students who lack experience in risk assessment to develop their expertise in that skill. The paper also suggests a classification technique for a fuzzy rule-based system that can be used to judge risk based on a fuzzy inference system. The student project will thus be further enhanced with respect to risk assessment. We then discuss the design of experiments to verify the proposed model.
文摘As a power infrastructure directly facing power users, transmission line is the direct power source of end users. Therefore, the normal operation of transmission line is a key link to ensure high-quality power supply service. Due to the wide range of transmission line erection, the erection site is mainly in urban areas with complex environment, and the insulation level is lower than the transmission network, resulting in high failure rate, heavy maintenance workload and more power outages caused by maintenance. In order to ensure the reliability demand of users, improve the satisfaction of users, and reduce the power failure caused by maintenance and fault, live working technology is proposed and applied to practical production. Live working is a kind of operation mode for inspection and maintenance under the condition of keeping all equipment of power grid without power failure. At present, most of the maintenance work and accident handling work in the transmission line can be completed under the condition of live operation. Therefore, the implementation of live operation can significantly reduce the power outage duration and power outage times of users and improve the reliability of power supply.
