The major objective of this work was to establish a structural state-space model to estimate the dynamic origin-destination(O-D) matrices for urban rail transit network, using in- and out-flows at each station from au...The major objective of this work was to establish a structural state-space model to estimate the dynamic origin-destination(O-D) matrices for urban rail transit network, using in- and out-flows at each station from automatic fare collection(AFC) system as the real time observed passenger flow counts. For lacking of measurable passenger flow information, the proposed model employs priori O-D matrices and travel time distribution from historical travel records in AFC system to establish the dynamic system equations. An arriving rate based on travel time distribution is defined to identify the dynamic interrelations between time-varying O-D flows and observed flows, which greatly decreases the computational complexity and improve the model's applicability for large-scale network. This methodology is tested in a real transit network from Beijing subway network in China through comparing the predicted matrices with the true matrices. Case study results indicate that the proposed model is effective and applicative for estimating dynamic O-D matrices for large-scale rail transit network.展开更多
In the early fault period of high-speed train systems, the interested characteristic signals are relatively weak and easily submerged in heavy noise. In order to solve this problem, a state-transition-algorithm (STA)-...In the early fault period of high-speed train systems, the interested characteristic signals are relatively weak and easily submerged in heavy noise. In order to solve this problem, a state-transition-algorithm (STA)-based adaptive stochastic resonance (SR) method is proposed, which provides an alternative solution to the problem that the traditional SR has fixed parameters or optimizes only a single parameter and ignores the interaction between parameters. To be specific, the frequency-shifted and re-scaling are firstly used to pre-process an actual large signal to meet the requirement of the adiabatic approximate small parameter. And then, the signal-to-noise ratio is used as the optimization target, and the STA-based adaptive SR is used to synchronously optimize the system parameters. Finally, the optimal extraction and frequency recovery of a weak characteristic signal from a broken rotor bar fault are realized. The proposed method is compared with the existing methods by the early broken rotor bar experiments of traction motor. Experiment results show that the proposed method is better than the other methods in extracting weak signals, and the validity of this method is verified.展开更多
Many practical systems in physics, biology, engineer- ing and information science exhibit impulsive dynamical behaviors due to abrupt changes at certain instants during the dynami- cal processes. The problems of finit...Many practical systems in physics, biology, engineer- ing and information science exhibit impulsive dynamical behaviors due to abrupt changes at certain instants during the dynami- cal processes. The problems of finite-time stab!lity analysis are investigated for a class of Markovian switching stochastic sys- tems, in which exist impulses at the switching instants. Multiple Lyapunov techniques are used to derive sufficient conditions for finite-time stochastic stability of the overall system. Furthermore, a state feedback controller, which stabilizes the closed loop sys- tems in the finite-time sense, is then addressed. Moreover, the controller appears not only in the shift part but also in the diffu- sion part of the underlying stochastic subsystem. The results are reduced to feasibility problems involving linear matrix inequalities （LMIs）. A numerical example is presented to illustrate the proposed methodology.展开更多
Model based implementation of a novel nonlinear adaptive filter for extraction of time varying sinusoids using Xilinx system generator has been presented in this work. The practicality of this filter model along with ...Model based implementation of a novel nonlinear adaptive filter for extraction of time varying sinusoids using Xilinx system generator has been presented in this work. The practicality of this filter model along with its performance makes it one of the foremost candidates to be applied on nonlinear systems for the purpose of estimation and extraction using reconfigurable hardware like FPGA. A design implementation and verification approach has been discussed for more efficient implementation. Timing and power analysis has been performed and the architecture has been optimized for speed and power to perform at higher frequency when integrated on a Xilinx FPGA. The proposed hardware oriented architecture has been successfully implemented and simulated. The simulation results to track a noisy input have also been shown to demonstrate the exceptional performance of the hardware based architecture developed.展开更多
The third in ter nati onal sta ndardizati on excha nge meeting themed on urban sustainability and high-quality development recently took place in Beijing, attracting nearly 140 representatives from ISO/TC 268 (sustain...The third in ter nati onal sta ndardizati on excha nge meeting themed on urban sustainability and high-quality development recently took place in Beijing, attracting nearly 140 representatives from ISO/TC 268 (sustainable cities and comm uni ties), CNIS, Nati onal En ergy Conservation Center, China Academy of Information and Communication Tech no logy, etc.展开更多
Based on the contact equivalent relation of smooth map-germs in singularity theory, the stability of equivariant bifurcation problems with two types of state variables and their unfoldings in the presence of parameter...Based on the contact equivalent relation of smooth map-germs in singularity theory, the stability of equivariant bifurcation problems with two types of state variables and their unfoldings in the presence of parameter symmetry is discussed. Some basic results are obtained. Transversality condition is used to characterize the stability of equavariant bifurcation problems.展开更多
Interviewer:Since President Duterte was sworn in on June 30th,2016,he has been very decisive and firm in pro-moting reform measures,and has won acknowledgement and rising support fromthe Philippine people.Could you pl...Interviewer:Since President Duterte was sworn in on June 30th,2016,he has been very decisive and firm in pro-moting reform measures,and has won acknowledgement and rising support fromthe Philippine people.Could you please brief us on the specific policy measures of President Duterte and their effects?H.E.Romana:President Duterte’s administration has several socio-economic priorities.These priorities are展开更多
基金Project(51478036)supported by the National Natural Science Foundation of ChinaProject(20120009110016)supported by Research Fund for Doctoral Program of Higher EducationChina
文摘The major objective of this work was to establish a structural state-space model to estimate the dynamic origin-destination(O-D) matrices for urban rail transit network, using in- and out-flows at each station from automatic fare collection(AFC) system as the real time observed passenger flow counts. For lacking of measurable passenger flow information, the proposed model employs priori O-D matrices and travel time distribution from historical travel records in AFC system to establish the dynamic system equations. An arriving rate based on travel time distribution is defined to identify the dynamic interrelations between time-varying O-D flows and observed flows, which greatly decreases the computational complexity and improve the model's applicability for large-scale network. This methodology is tested in a real transit network from Beijing subway network in China through comparing the predicted matrices with the true matrices. Case study results indicate that the proposed model is effective and applicative for estimating dynamic O-D matrices for large-scale rail transit network.
基金Projects(61490702,61773407,61803390,61751312)supported by the National Natural Science Foundation of ChinaProject(61725306)supported by the National Science Foundation for Distinguished Young Scholars of China+5 种基金Project(61621062)supported by the Foundation for Innovative Research Groups of the National Natural Science Foundation of ChinaProject(2017TP1002)supported by Hunan Provincial Key Laboratory,ChinaProject(6141A0202210)supported by the Program of the Joint Pre-research Foundation of the Chinese Ministry of EducationProject(61400030501)supported by the General Program of the Equipment Pre-research Field Foundation of ChinaProject(2016TP1023)supported by the Science and Technology Project in Hunan Province Hunan Science and Technology Agency of ChinaProject(2018FJ34)supported by the Science and Technology Project in Shaoyang Science and Technology Agency of China
文摘In the early fault period of high-speed train systems, the interested characteristic signals are relatively weak and easily submerged in heavy noise. In order to solve this problem, a state-transition-algorithm (STA)-based adaptive stochastic resonance (SR) method is proposed, which provides an alternative solution to the problem that the traditional SR has fixed parameters or optimizes only a single parameter and ignores the interaction between parameters. To be specific, the frequency-shifted and re-scaling are firstly used to pre-process an actual large signal to meet the requirement of the adiabatic approximate small parameter. And then, the signal-to-noise ratio is used as the optimization target, and the STA-based adaptive SR is used to synchronously optimize the system parameters. Finally, the optimal extraction and frequency recovery of a weak characteristic signal from a broken rotor bar fault are realized. The proposed method is compared with the existing methods by the early broken rotor bar experiments of traction motor. Experiment results show that the proposed method is better than the other methods in extracting weak signals, and the validity of this method is verified.
基金supported in part by the National Natural Science Foundation of China(60374015)
文摘Many practical systems in physics, biology, engineer- ing and information science exhibit impulsive dynamical behaviors due to abrupt changes at certain instants during the dynami- cal processes. The problems of finite-time stab!lity analysis are investigated for a class of Markovian switching stochastic sys- tems, in which exist impulses at the switching instants. Multiple Lyapunov techniques are used to derive sufficient conditions for finite-time stochastic stability of the overall system. Furthermore, a state feedback controller, which stabilizes the closed loop sys- tems in the finite-time sense, is then addressed. Moreover, the controller appears not only in the shift part but also in the diffu- sion part of the underlying stochastic subsystem. The results are reduced to feasibility problems involving linear matrix inequalities （LMIs）. A numerical example is presented to illustrate the proposed methodology.
文摘Model based implementation of a novel nonlinear adaptive filter for extraction of time varying sinusoids using Xilinx system generator has been presented in this work. The practicality of this filter model along with its performance makes it one of the foremost candidates to be applied on nonlinear systems for the purpose of estimation and extraction using reconfigurable hardware like FPGA. A design implementation and verification approach has been discussed for more efficient implementation. Timing and power analysis has been performed and the architecture has been optimized for speed and power to perform at higher frequency when integrated on a Xilinx FPGA. The proposed hardware oriented architecture has been successfully implemented and simulated. The simulation results to track a noisy input have also been shown to demonstrate the exceptional performance of the hardware based architecture developed.
文摘The third in ter nati onal sta ndardizati on excha nge meeting themed on urban sustainability and high-quality development recently took place in Beijing, attracting nearly 140 representatives from ISO/TC 268 (sustainable cities and comm uni ties), CNIS, Nati onal En ergy Conservation Center, China Academy of Information and Communication Tech no logy, etc.
基金Project supported by the National Natural Science Foundation of China(No.10671002)the Natural Science Foundation of Hunan Province of China(No.04JJ3072)the Science Foundation of the Education Department of Hunan Province of China(No.04C383)
文摘Based on the contact equivalent relation of smooth map-germs in singularity theory, the stability of equivariant bifurcation problems with two types of state variables and their unfoldings in the presence of parameter symmetry is discussed. Some basic results are obtained. Transversality condition is used to characterize the stability of equavariant bifurcation problems.
文摘Interviewer:Since President Duterte was sworn in on June 30th,2016,he has been very decisive and firm in pro-moting reform measures,and has won acknowledgement and rising support fromthe Philippine people.Could you please brief us on the specific policy measures of President Duterte and their effects?H.E.Romana:President Duterte’s administration has several socio-economic priorities.These priorities are
