The method of cross-ocean GPS long distance rapid static positioning has become one of the main technical means of GPS static positioning away from the mainland. The key technology had been analyzed in-cluding data pr...The method of cross-ocean GPS long distance rapid static positioning has become one of the main technical means of GPS static positioning away from the mainland. The key technology had been analyzed in-cluding data preprocessing and quality control, long distance integer ambiguity resolution and static Kalman filter parameter estimation. Effective data processing method of cross-ocean GPS long baseline rapid static positioning had been proposed. Through the analysis of practical examples of coastal and ocean, the feasibility of cross-ocean GPS long distance rapid static positioning based on the method is testified and verified. The results show that the accuracy of one-hour single baseline static positioning for the 500 - 600 km distance can be better than 10cm in the three-dimensional coordinates ocean environment. , which can suffice static positioning accuracy in the special展开更多
Retinal prosthesis offers a potential treatment for individuals suffering from photoreceptor degeneration diseases.Establishing biological retinal models and simulating how the biological retina convert incoming light...Retinal prosthesis offers a potential treatment for individuals suffering from photoreceptor degeneration diseases.Establishing biological retinal models and simulating how the biological retina convert incoming light signal into spike trains that can be properly decoded by the brain is a key issue.Some retinal models have been presented,ranking from structural models inspired by the layered architecture to functional models originated from a set of specific physiological phenomena.However,Most of these focus on stimulus image compression,edge detection and reconstruction,but do not generate spike trains corresponding to visual image.In this study,based on stateof-the-art retinal physiological mechanism,including effective visual information extraction,static nonlinear rectification of biological systems and neurons Poisson coding,a cascade model of the retina including the out plexiform layer for information processing and the inner plexiform layer for information encoding was brought forward,which integrates both anatomic connections and functional computations of retina.Using MATLAB software,spike trains corresponding to stimulus image were numerically computed by four steps:linear spatiotemporal filtering,static nonlinear rectification,radial sampling and then Poisson spike generation.The simulated results suggested that such a cascade model could recreate visual information processing and encoding functionalities of the retina,which is helpful in developing artificial retina for the retinally blind.展开更多
文摘The method of cross-ocean GPS long distance rapid static positioning has become one of the main technical means of GPS static positioning away from the mainland. The key technology had been analyzed in-cluding data preprocessing and quality control, long distance integer ambiguity resolution and static Kalman filter parameter estimation. Effective data processing method of cross-ocean GPS long baseline rapid static positioning had been proposed. Through the analysis of practical examples of coastal and ocean, the feasibility of cross-ocean GPS long distance rapid static positioning based on the method is testified and verified. The results show that the accuracy of one-hour single baseline static positioning for the 500 - 600 km distance can be better than 10cm in the three-dimensional coordinates ocean environment. , which can suffice static positioning accuracy in the special
基金supported by the National Natural Science Foundation of China,No.30870649the National Program on Key Basic Research Project of China (973 Program),No.2005CB724302
文摘Retinal prosthesis offers a potential treatment for individuals suffering from photoreceptor degeneration diseases.Establishing biological retinal models and simulating how the biological retina convert incoming light signal into spike trains that can be properly decoded by the brain is a key issue.Some retinal models have been presented,ranking from structural models inspired by the layered architecture to functional models originated from a set of specific physiological phenomena.However,Most of these focus on stimulus image compression,edge detection and reconstruction,but do not generate spike trains corresponding to visual image.In this study,based on stateof-the-art retinal physiological mechanism,including effective visual information extraction,static nonlinear rectification of biological systems and neurons Poisson coding,a cascade model of the retina including the out plexiform layer for information processing and the inner plexiform layer for information encoding was brought forward,which integrates both anatomic connections and functional computations of retina.Using MATLAB software,spike trains corresponding to stimulus image were numerically computed by four steps:linear spatiotemporal filtering,static nonlinear rectification,radial sampling and then Poisson spike generation.The simulated results suggested that such a cascade model could recreate visual information processing and encoding functionalities of the retina,which is helpful in developing artificial retina for the retinally blind.