Power Line Communications-Artificial Intelligence of Things(PLC-AIo T)combines the low cost and high coverage of PLC with the learning ability of Artificial Intelligence(AI)to provide data collection and transmission ...Power Line Communications-Artificial Intelligence of Things(PLC-AIo T)combines the low cost and high coverage of PLC with the learning ability of Artificial Intelligence(AI)to provide data collection and transmission capabilities for PLC-AIo T devices in smart parks.With the development of smart parks,their emerging services require secure and accurate time synchronization of PLC-AIo T devices.However,the impact of attackers on the accuracy of time synchronization cannot be ignored.To solve the aforementioned problems,we propose a tampering attack-aware Deep Q-Network(DQN)-based time synchronization algorithm.First,we construct an abnormal clock source detection model.Then,the abnormal clock source is detected and excluded by comparing the time synchronization information between the device and the gateway.Finally,the proposed algorithm realizes the joint guarantee of high accuracy and low delay for PLC-AIo T in smart parks by intelligently selecting the multi-clock source cooperation strategy and timing weights.Simulation results show that the proposed algorithm has better time synchronization delay and accuracy performance.展开更多
Objective HEPS is a fourth-generation photon source under construction.HEPS adopts the magnetic focusing structure of 7BA,and the beam dynamics aperture is very small.HEPS injection scheme adopts the on-axis injection...Objective HEPS is a fourth-generation photon source under construction.HEPS adopts the magnetic focusing structure of 7BA,and the beam dynamics aperture is very small.HEPS injection scheme adopts the on-axis injection scheme.To minimize perturbation on adjacent bunches during on-axis swap out injection,a set of superfast kicker and high-voltage fast pulse power supply are needed.The high-voltage fast pulse power supply uses pulsed power stacking technologies,and the power supply needs the multichannel and low jitter clock signal.Therefore,it is necessary to develop a precise clock source.Method The clock source adopts FPGA controller with full digital control,and the output pulse mode of the system can be adjusted in real time.A detection module based on program control is used to check repetition rate and bottom width of input clock and output clock in real time.High-speed and precision clock signal output circuit is used to guarantee signal integrity and reduce clock signal jitter.Conclusion The prototype experiment proves that the output clock can well meet requirements of design.The minimum bottom width of the independent clock is 5 ns,the minimum time interval of the two groups of clocks is 5 ns,and the jitter of output clock is lower than 50 ps.The developed clock source can well meet the application requirements of high-voltage fast pulse power supply in HEPS injection system.展开更多
With the increasingly high requirement of clock source accuracy for seismic data servers and equipment,the development of a multipurpose timing system is urgently needed in the seismic industry. We have developed low-...With the increasingly high requirement of clock source accuracy for seismic data servers and equipment,the development of a multipurpose timing system is urgently needed in the seismic industry. We have developed low-cost timing equipment according to the actual earthquake industry situation. This set of timing equipment can provide a unified solution to the different environment and different earthquake instruments with different timing precision demands.展开更多
基金supported by the Science and Technology Project of the State Grid Corporation of China under Grant Number 5400202199541A-0-5-ZN。
文摘Power Line Communications-Artificial Intelligence of Things(PLC-AIo T)combines the low cost and high coverage of PLC with the learning ability of Artificial Intelligence(AI)to provide data collection and transmission capabilities for PLC-AIo T devices in smart parks.With the development of smart parks,their emerging services require secure and accurate time synchronization of PLC-AIo T devices.However,the impact of attackers on the accuracy of time synchronization cannot be ignored.To solve the aforementioned problems,we propose a tampering attack-aware Deep Q-Network(DQN)-based time synchronization algorithm.First,we construct an abnormal clock source detection model.Then,the abnormal clock source is detected and excluded by comparing the time synchronization information between the device and the gateway.Finally,the proposed algorithm realizes the joint guarantee of high accuracy and low delay for PLC-AIo T in smart parks by intelligently selecting the multi-clock source cooperation strategy and timing weights.Simulation results show that the proposed algorithm has better time synchronization delay and accuracy performance.
文摘Objective HEPS is a fourth-generation photon source under construction.HEPS adopts the magnetic focusing structure of 7BA,and the beam dynamics aperture is very small.HEPS injection scheme adopts the on-axis injection scheme.To minimize perturbation on adjacent bunches during on-axis swap out injection,a set of superfast kicker and high-voltage fast pulse power supply are needed.The high-voltage fast pulse power supply uses pulsed power stacking technologies,and the power supply needs the multichannel and low jitter clock signal.Therefore,it is necessary to develop a precise clock source.Method The clock source adopts FPGA controller with full digital control,and the output pulse mode of the system can be adjusted in real time.A detection module based on program control is used to check repetition rate and bottom width of input clock and output clock in real time.High-speed and precision clock signal output circuit is used to guarantee signal integrity and reduce clock signal jitter.Conclusion The prototype experiment proves that the output clock can well meet requirements of design.The minimum bottom width of the independent clock is 5 ns,the minimum time interval of the two groups of clocks is 5 ns,and the jitter of output clock is lower than 50 ps.The developed clock source can well meet the application requirements of high-voltage fast pulse power supply in HEPS injection system.
基金supported by the Xinjiang Earthquake Science Foundation(201308)
文摘With the increasingly high requirement of clock source accuracy for seismic data servers and equipment,the development of a multipurpose timing system is urgently needed in the seismic industry. We have developed low-cost timing equipment according to the actual earthquake industry situation. This set of timing equipment can provide a unified solution to the different environment and different earthquake instruments with different timing precision demands.
