A perimeter traffic signal control strategy is proposed based on the macroscopic fundamental diagram theory(MFD)to solve the signal control problem in oversaturated states.First,the MFD of a specific regional network ...A perimeter traffic signal control strategy is proposed based on the macroscopic fundamental diagram theory(MFD)to solve the signal control problem in oversaturated states.First,the MFD of a specific regional network can be derived using VSS IM simulation software.Secondly,the maximum number of cumulative vehicles that the network can accommodate is determined based on the MFD.Then,through monitoring the influx flow,the number of vehicles existing in and exiting from the network,a perimeter traffic control model is proposed to optimize the signal timing of the boundary intersections.Finally,a virtual network simulation model is established and three different kinds o f traffic demand are loaded into the network.Simulation results show that a fer the strategy implementation,the number o f vehicles accumulating in the network can be kept near the optimal value,while the number o f both entering and exiting vehicles increases significantly and the road network can be maintained at a large capacity.Simultaneously,the queue length at the approach of the border intersections is reasonably controlled and vehicles entering and exiting the network can maintain a more efficient and stable speed.The network performance indices such as the average traffic delay and average number of stops can be improved to a certain degree,thus verifying the effectiveness and feasibility of the perimeter control strategy.展开更多
This letter studies and analyzes the working features of main circuit of tri-level boost Power Factor Correct(PFC) converter and the advantages of tri-level switch converter in aspects of bearing high-voltage of power...This letter studies and analyzes the working features of main circuit of tri-level boost Power Factor Correct(PFC) converter and the advantages of tri-level switch converter in aspects of bearing high-voltage of power components,overall system loss and magnetic component selection based upon the single-level boost PFC switch converter.Besides,relying on the application of mi-croprocessor in power converter technology and DSP(Digital Signal Processing) chip's strong cal-culating capacity,the letter presents the adoption of modified scheme of tri-level boost PFC converter under the control of predictive control algorithm.Moreover,the operating principle and control method are specified,the results of circuit test and analysis are provided and the advantages of pre-dictive control technology-based multi-level boost PFC converter is verified.展开更多
Compact, hot-pluggable, and data-agnostic, SFP modules bring up to 4.25 Gbps to a flexible new form factor. The SFP transceiver which is the core device of optical communication is always the research focus in the fie...Compact, hot-pluggable, and data-agnostic, SFP modules bring up to 4.25 Gbps to a flexible new form factor. The SFP transceiver which is the core device of optical communication is always the research focus in the field of optical communication for both telecommunication and data communication applications. The working principles of SFP including the transmitter components, the receiver components and the microcontroller are discussed in detail. The basic theory of high-speed signal and the concept of high - speed circuit, high-speed board design techniques are presented. A new design of high performance, cost effective SFP transceiver and PCB layout are also presented. The performance of the transceiver is analyzed and the characteristics of the sample are coincident with the expected ones. The status of the transceiver can be monitored and controlled by F C bus through the interface in real time. This transceiver can meet the requirement of SFF-8472.展开更多
基金The National Natural Science Foundation of China(No.51308227)the Fundamental Research Funds for the Central Universities(No.201522087)+1 种基金the Science and Technology Planning Project of Guangdong Province(No.2016A030305001)the Project of Department of Communications of Guangdong Province(No.2015-02-070)
文摘A perimeter traffic signal control strategy is proposed based on the macroscopic fundamental diagram theory(MFD)to solve the signal control problem in oversaturated states.First,the MFD of a specific regional network can be derived using VSS IM simulation software.Secondly,the maximum number of cumulative vehicles that the network can accommodate is determined based on the MFD.Then,through monitoring the influx flow,the number of vehicles existing in and exiting from the network,a perimeter traffic control model is proposed to optimize the signal timing of the boundary intersections.Finally,a virtual network simulation model is established and three different kinds o f traffic demand are loaded into the network.Simulation results show that a fer the strategy implementation,the number o f vehicles accumulating in the network can be kept near the optimal value,while the number o f both entering and exiting vehicles increases significantly and the road network can be maintained at a large capacity.Simultaneously,the queue length at the approach of the border intersections is reasonably controlled and vehicles entering and exiting the network can maintain a more efficient and stable speed.The network performance indices such as the average traffic delay and average number of stops can be improved to a certain degree,thus verifying the effectiveness and feasibility of the perimeter control strategy.
文摘This letter studies and analyzes the working features of main circuit of tri-level boost Power Factor Correct(PFC) converter and the advantages of tri-level switch converter in aspects of bearing high-voltage of power components,overall system loss and magnetic component selection based upon the single-level boost PFC switch converter.Besides,relying on the application of mi-croprocessor in power converter technology and DSP(Digital Signal Processing) chip's strong cal-culating capacity,the letter presents the adoption of modified scheme of tri-level boost PFC converter under the control of predictive control algorithm.Moreover,the operating principle and control method are specified,the results of circuit test and analysis are provided and the advantages of pre-dictive control technology-based multi-level boost PFC converter is verified.
文摘Compact, hot-pluggable, and data-agnostic, SFP modules bring up to 4.25 Gbps to a flexible new form factor. The SFP transceiver which is the core device of optical communication is always the research focus in the field of optical communication for both telecommunication and data communication applications. The working principles of SFP including the transmitter components, the receiver components and the microcontroller are discussed in detail. The basic theory of high-speed signal and the concept of high - speed circuit, high-speed board design techniques are presented. A new design of high performance, cost effective SFP transceiver and PCB layout are also presented. The performance of the transceiver is analyzed and the characteristics of the sample are coincident with the expected ones. The status of the transceiver can be monitored and controlled by F C bus through the interface in real time. This transceiver can meet the requirement of SFF-8472.
