At present,ZPW-2000 track circuit fault diagnosis is artificially analyzed and monitored.Its discrimination method not only is low efficient and takes a long period,but also requires highly experienced personnel to an...At present,ZPW-2000 track circuit fault diagnosis is artificially analyzed and monitored.Its discrimination method not only is low efficient and takes a long period,but also requires highly experienced personnel to analyze the data.Therefore,we introduce kernel principal component analysis and stacked auto-encoder network(KPCA-SAD)into the fault diagnosis of ZPW-2000 track circuit.According to the working principle and fault characteristics of track circuit,a fault diagnosis model of KPCA-SAE network is established.The relevant parameters of key components recorded in the data collected by field staff are used as the fault feature parameters.The KPCA method is used to reduce the dimension and noise of fault document matrix to avoid information redundancy.The SAE network is trained by the processed fault data.The model parameters are optimized overall by using back propagation(BP)algorithm.The KPCA-SAE model is simulated in Matlab platform and is finally proved to be effective and feasible.Compared with the traditional method of artificially analyzing fault data and other intelligent algorithms,the KPCA-SAE based classifier has higher fault identification accuracy.展开更多
For the purpose of investigating conditions of earthquake pregnancies,a heterogeneous 2-D single fault model with 81 × 81 cells is set up. By using cellular automata models and changing the model heterogeneity an...For the purpose of investigating conditions of earthquake pregnancies,a heterogeneous 2-D single fault model with 81 × 81 cells is set up. By using cellular automata models and changing the model heterogeneity and correlation parameters, we compute and get different synthetic event catalogues for analyzing general seismic activity and intensity distribution properties. The results show that different heterogeneous structures produce different seismic sequence types and G-R relationship,so the heterogeneity is an important influencing factor on seismicity. Nevertheless,both the coefficients of stress redistribution and local friction loss can also influence seismicity to some extent. This is possibly useful for further understanding of the complexity of earthquake processes.展开更多
In this paper, form vulnerability theory was applied to the analysis of the failure mechanisms of single-layer latticed spherical shells subjected to seismic excitations. Three 1/10 scale testing models were designed ...In this paper, form vulnerability theory was applied to the analysis of the failure mechanisms of single-layer latticed spherical shells subjected to seismic excitations. Three 1/10 scale testing models were designed with characteristics as follows： Model 1 possesses overall uniform stiffness and is expected to collapse in the strength failure mode as some members become plastic; Model 2 possesses six man-made weak parts located on six radial main rib zones and is expected to collapse in the dynamic in- stability mode with all members still in the elastic stage; Model 3 strengthens the six weak zones of Model 2, and therefore, its stiffness is uniform. Model 3 is proposed to collapse in the strength failure mode when the members are still in the elastic stage By increasing the peak ground accelerations of seismic waves gradually, the shaking table tests were carried out until all three models collapsed （or locally collapsed）. On the basis of form vulnerability theory, topological hierarchy models of the test models were established through a clustering process, and various failure scenarios, including overall collapse scenarios and partial collapse scenarios, were identified by unzipping corresponding hierarchical models. By comparison of the failure scenarios based on theoretical analysis and experiments, it was found that vulnerability theory could effectively reflect the weak- ness zones in topological relations of the structures from the perspective of internal causes. The intemal mechanisms of the distinct failure characteristics of reticulated shells subjected to seismic excitations were also revealed in this process. The well-formedness of structural clusters, Q, is closely related to the collapse modes, i.e., uniform changes of Q indicate a uniform distribution of overall structural stiffness, which indicates that strength failure is likely to happen; conversely, non-uniform changes of Q indicate that weak zones exist in the structure, and dynamic instability is likely to occur.展开更多
基金National Natural Science Foundation of China(No.61763023)。
文摘At present,ZPW-2000 track circuit fault diagnosis is artificially analyzed and monitored.Its discrimination method not only is low efficient and takes a long period,but also requires highly experienced personnel to analyze the data.Therefore,we introduce kernel principal component analysis and stacked auto-encoder network(KPCA-SAD)into the fault diagnosis of ZPW-2000 track circuit.According to the working principle and fault characteristics of track circuit,a fault diagnosis model of KPCA-SAE network is established.The relevant parameters of key components recorded in the data collected by field staff are used as the fault feature parameters.The KPCA method is used to reduce the dimension and noise of fault document matrix to avoid information redundancy.The SAE network is trained by the processed fault data.The model parameters are optimized overall by using back propagation(BP)algorithm.The KPCA-SAE model is simulated in Matlab platform and is finally proved to be effective and feasible.Compared with the traditional method of artificially analyzing fault data and other intelligent algorithms,the KPCA-SAE based classifier has higher fault identification accuracy.
基金funded by the National Natural Science Foundation of China ( Grant No. 40774015)
文摘For the purpose of investigating conditions of earthquake pregnancies,a heterogeneous 2-D single fault model with 81 × 81 cells is set up. By using cellular automata models and changing the model heterogeneity and correlation parameters, we compute and get different synthetic event catalogues for analyzing general seismic activity and intensity distribution properties. The results show that different heterogeneous structures produce different seismic sequence types and G-R relationship,so the heterogeneity is an important influencing factor on seismicity. Nevertheless,both the coefficients of stress redistribution and local friction loss can also influence seismicity to some extent. This is possibly useful for further understanding of the complexity of earthquake processes.
基金supported by the National Natural Science Foundation of China (Grant No. 90715005)the New Century Excellent Talent of Ministry of Education of China (Grant No. NCET-07-0186)the Doctoral Fund of Ministry of China (Grant No. 200802860007)
文摘In this paper, form vulnerability theory was applied to the analysis of the failure mechanisms of single-layer latticed spherical shells subjected to seismic excitations. Three 1/10 scale testing models were designed with characteristics as follows： Model 1 possesses overall uniform stiffness and is expected to collapse in the strength failure mode as some members become plastic; Model 2 possesses six man-made weak parts located on six radial main rib zones and is expected to collapse in the dynamic in- stability mode with all members still in the elastic stage; Model 3 strengthens the six weak zones of Model 2, and therefore, its stiffness is uniform. Model 3 is proposed to collapse in the strength failure mode when the members are still in the elastic stage By increasing the peak ground accelerations of seismic waves gradually, the shaking table tests were carried out until all three models collapsed （or locally collapsed）. On the basis of form vulnerability theory, topological hierarchy models of the test models were established through a clustering process, and various failure scenarios, including overall collapse scenarios and partial collapse scenarios, were identified by unzipping corresponding hierarchical models. By comparison of the failure scenarios based on theoretical analysis and experiments, it was found that vulnerability theory could effectively reflect the weak- ness zones in topological relations of the structures from the perspective of internal causes. The intemal mechanisms of the distinct failure characteristics of reticulated shells subjected to seismic excitations were also revealed in this process. The well-formedness of structural clusters, Q, is closely related to the collapse modes, i.e., uniform changes of Q indicate a uniform distribution of overall structural stiffness, which indicates that strength failure is likely to happen; conversely, non-uniform changes of Q indicate that weak zones exist in the structure, and dynamic instability is likely to occur.
