We present two approaches to system identification, i.e. the identification of partial differentialequations (PDEs) from measurement data. The first is a regression-based variational systemidentification procedure tha...We present two approaches to system identification, i.e. the identification of partial differentialequations (PDEs) from measurement data. The first is a regression-based variational systemidentification procedure that is advantageous in not requiring repeated forward model solves andhas good scalability to large number of differential operators. However it has strict data typerequirements needing the ability to directly represent the operators through the available data.The second is a Bayesian inference framework highly valuable for providing uncertaintyquantification, and flexible for accommodating sparse and noisy data that may also be indirectquantities of interest. However, it also requires repeated forward solutions of the PDE modelswhich is expensive and hinders scalability. We provide illustrations of results on a model problemfor pattern formation dynamics, and discuss merits of the presented methods.展开更多
This paper presents a detailed technical overview of the femtosecond precision timing and synchronization systems implemented at the Shanghai high repetition rate XFEL and extreme light facility(SHINE).These systems a...This paper presents a detailed technical overview of the femtosecond precision timing and synchronization systems implemented at the Shanghai high repetition rate XFEL and extreme light facility(SHINE).These systems are designed to deliver stabilized optical references to multiple receiver clients,ensuring high-precision synchronization between the optical master oscillator(OMO)and optical/RF subsystems.The core components include an OMO,fiber length stabilizers and laser-to-laser synchronization modules that achieve femtosecond-level accuracy.Our discussion extends to the various subsystems that comprise the synchronization infrastructure,including the OMO,fiber length stabilizer and advanced phase detection techniques.Finally,we highlight ongoing research and development efforts aimed at enhancing the functionality and efficiency of these systems,thereby contributing to the advancement of X-ray freeelectron laser technology and its applications in scientific research.展开更多
基金We acknowledge the support of Defense Advanced Research Projects Agency(Grant HR00111990S2)Toyota Research Institute(Award#849910).
文摘We present two approaches to system identification, i.e. the identification of partial differentialequations (PDEs) from measurement data. The first is a regression-based variational systemidentification procedure that is advantageous in not requiring repeated forward model solves andhas good scalability to large number of differential operators. However it has strict data typerequirements needing the ability to directly represent the operators through the available data.The second is a Bayesian inference framework highly valuable for providing uncertaintyquantification, and flexible for accommodating sparse and noisy data that may also be indirectquantities of interest. However, it also requires repeated forward solutions of the PDE modelswhich is expensive and hinders scalability. We provide illustrations of results on a model problemfor pattern formation dynamics, and discuss merits of the presented methods.
基金supported by the National Natural Science Foundation of China(Nos.12105348 and 12275341)the SHINE project(National Major Scientific and Technological Infrastructure,No.NDRC[2017]825).
文摘This paper presents a detailed technical overview of the femtosecond precision timing and synchronization systems implemented at the Shanghai high repetition rate XFEL and extreme light facility(SHINE).These systems are designed to deliver stabilized optical references to multiple receiver clients,ensuring high-precision synchronization between the optical master oscillator(OMO)and optical/RF subsystems.The core components include an OMO,fiber length stabilizers and laser-to-laser synchronization modules that achieve femtosecond-level accuracy.Our discussion extends to the various subsystems that comprise the synchronization infrastructure,including the OMO,fiber length stabilizer and advanced phase detection techniques.Finally,we highlight ongoing research and development efforts aimed at enhancing the functionality and efficiency of these systems,thereby contributing to the advancement of X-ray freeelectron laser technology and its applications in scientific research.
