The integration of Global Navigation Satellite System(GNSS)technology into railway train control systems is a crucial step toward achieving the vision of a digital railway.Traditional train control systems undergo ext...The integration of Global Navigation Satellite System(GNSS)technology into railway train control systems is a crucial step toward achieving the vision of a digital railway.Traditional train control systems undergo extensive in-house tests and prolonged field tests for certification and approval before operational deployment,leading to high costs,delays,and operational disruptions.This paper introduces a GNSS-based train control localization framework which eliminates the need for on-site testing by leveraging train movement dynamics and 3D environment modeling to create a zero on-site testing platform.The proposed framework simulates train movement and the surrounding 3D environment using collected railway line location data and environmental attributes to generate realistic multipath signals and obscuration effects.This approach enables comprehensive laboratory-based case studies for train localization,reducing the huge amount test of needed for physical field trials.The framework is established in house,using the data collected at the Test Base of China Academy of Railway Sciences(Circular Railway).Results from the open area and cutting environment tests demonstrate high localization accuracy repeatability within the simulated environment,validating the feasibility and effectiveness of zero on-site testing for GNSS-based train control systems.This research highlights the potential of GNSS simulation platforms in enhancing cost efficiency,operational safety,and accuracy for future digital railways.展开更多
In order to meet the requirements for zero value stability of direct sequence spread spectrum(DSSS) signal processing in high dynamic scenario,digital automatic gain control(AGC) is employed to regulate power.However,...In order to meet the requirements for zero value stability of direct sequence spread spectrum(DSSS) signal processing in high dynamic scenario,digital automatic gain control(AGC) is employed to regulate power.However,conventional AGC causes degradation in the synchronization performance of DSSS receiver.Based on the theoretical analysis of the influence of digital AGC on DSSS signal synchronization,this paper proposes a new AGC algorithm,which is applicable to multi-channel digital DSSS signal receiver.By making power adjustment cycle and synchronization cycle coherent with each other adaptively,the influence of digital AGC on subsequent synchronization processing has been eliminated.Theoretical analysis,simulation results and experimental data verify the validity of the proposed algorithm.By virtue of the proposed algorithm,the influence of digital AGC on DSSS signal synchronization is eliminated.This algorithm applies to an aerospace engineering project successfully.展开更多
In developmental biology,knowledge of cell structure and their(morpho)dynamic behavior,leads to a comprehensive understanding of their conducts and the mechanisms in which they participate.This knowledge is a decisive...In developmental biology,knowledge of cell structure and their(morpho)dynamic behavior,leads to a comprehensive understanding of their conducts and the mechanisms in which they participate.This knowledge is a decisive factor in biological research and also in all drug development steps,medicinal or preventive therapies.Experimental cell analysis is hard,expensive,and time-consuming.To overcome these difficulties,in recent years,several computational object tracking methods,software system and packages have been developed in cell sciences that bring together different disciplines and branches of technologies.Object tracking is the process of locating and monitoring specific object and its behavior in sequential images.In this paper,a comprehensive review on object tracking stages and computational methods that are utilized in terms of cell tracking has been organized.Besides,the available software packages and toolkits,challenges,and their solution in time lapse microscopy images in this scope were reviewed.The aim of describing computational cell tracking methods and tools is that biologist and cell scientists might take advantage of these computational techniques to find another method to gain complementary information for their question of interest.展开更多
基金supported by the National Natural Science Foundation of China(62027809,U2268206,T2222015,U2468202).
文摘The integration of Global Navigation Satellite System(GNSS)technology into railway train control systems is a crucial step toward achieving the vision of a digital railway.Traditional train control systems undergo extensive in-house tests and prolonged field tests for certification and approval before operational deployment,leading to high costs,delays,and operational disruptions.This paper introduces a GNSS-based train control localization framework which eliminates the need for on-site testing by leveraging train movement dynamics and 3D environment modeling to create a zero on-site testing platform.The proposed framework simulates train movement and the surrounding 3D environment using collected railway line location data and environmental attributes to generate realistic multipath signals and obscuration effects.This approach enables comprehensive laboratory-based case studies for train localization,reducing the huge amount test of needed for physical field trials.The framework is established in house,using the data collected at the Test Base of China Academy of Railway Sciences(Circular Railway).Results from the open area and cutting environment tests demonstrate high localization accuracy repeatability within the simulated environment,validating the feasibility and effectiveness of zero on-site testing for GNSS-based train control systems.This research highlights the potential of GNSS simulation platforms in enhancing cost efficiency,operational safety,and accuracy for future digital railways.
基金support of the National High Technology Research and Development Program of China(863)(Grant No.2013AA1548)
文摘In order to meet the requirements for zero value stability of direct sequence spread spectrum(DSSS) signal processing in high dynamic scenario,digital automatic gain control(AGC) is employed to regulate power.However,conventional AGC causes degradation in the synchronization performance of DSSS receiver.Based on the theoretical analysis of the influence of digital AGC on DSSS signal synchronization,this paper proposes a new AGC algorithm,which is applicable to multi-channel digital DSSS signal receiver.By making power adjustment cycle and synchronization cycle coherent with each other adaptively,the influence of digital AGC on subsequent synchronization processing has been eliminated.Theoretical analysis,simulation results and experimental data verify the validity of the proposed algorithm.By virtue of the proposed algorithm,the influence of digital AGC on DSSS signal synchronization is eliminated.This algorithm applies to an aerospace engineering project successfully.
文摘In developmental biology,knowledge of cell structure and their(morpho)dynamic behavior,leads to a comprehensive understanding of their conducts and the mechanisms in which they participate.This knowledge is a decisive factor in biological research and also in all drug development steps,medicinal or preventive therapies.Experimental cell analysis is hard,expensive,and time-consuming.To overcome these difficulties,in recent years,several computational object tracking methods,software system and packages have been developed in cell sciences that bring together different disciplines and branches of technologies.Object tracking is the process of locating and monitoring specific object and its behavior in sequential images.In this paper,a comprehensive review on object tracking stages and computational methods that are utilized in terms of cell tracking has been organized.Besides,the available software packages and toolkits,challenges,and their solution in time lapse microscopy images in this scope were reviewed.The aim of describing computational cell tracking methods and tools is that biologist and cell scientists might take advantage of these computational techniques to find another method to gain complementary information for their question of interest.
