How to get the rapid and stable inversion results and reconstruct the clear subsurface resistivity structures is a focus problem in current magnetotelluric inversion. A stable solution of an ill-posed inverse problem ...How to get the rapid and stable inversion results and reconstruct the clear subsurface resistivity structures is a focus problem in current magnetotelluric inversion. A stable solution of an ill-posed inverse problem was obtained by the regularization methods in which some desired structures were imposed to stabilize the inverse problem. By the smoothness-constrained model and approximate sensitivity method, the stable subsurface resistivity structures were reconstructed. The synthetic examples show that the smoothness-constrained regularized inversion method is effective and can be reasonable to reconstruct three-dimensional subsurface resistivity structures.展开更多
A class of general inverse matrix techniques based on adaptive algorithmic modelling methodologies is derived yielding iterative methods for solving unsymmetric linear systems of irregular structure arising in complex...A class of general inverse matrix techniques based on adaptive algorithmic modelling methodologies is derived yielding iterative methods for solving unsymmetric linear systems of irregular structure arising in complex computational problems in three space dimensions. The proposed class of approximate inverse is chosen as the basis to yield systems on which classic and preconditioned iterative methods are explicitly applied. Optimized versions of the proposed approximate inverse are presented using special storage (k-sweep) techniques leading to economical forms of the approximate inverses. Application of the adaptive algorithmic methodologies on a characteristic nonlinear boundary value problem is discussed and numerical results are given.展开更多
Full waveform inversion size of full waveform inversion will and the limitation of full waveform is mainly used to obtain high resolution velocity models of subsurface. The lead to a gigantic computation cost. Under t...Full waveform inversion size of full waveform inversion will and the limitation of full waveform is mainly used to obtain high resolution velocity models of subsurface. The lead to a gigantic computation cost. Under the available computer resource inversion, the authors propose L-BFGS algorithm as the optimization method to solve this problem. In order to demonstrate the flexibility of the method, three different numerical experi- ments have been done to analyze the properties of full waveform inversion based on L-BFGS.展开更多
The time evolution of system in two photon Jaynes Cummings (J C) model without rotating waves approximation (RWA) is obtained by using the theory of ordinary differential equations. Based on the evolution, the mean ...The time evolution of system in two photon Jaynes Cummings (J C) model without rotating waves approximation (RWA) is obtained by using the theory of ordinary differential equations. Based on the evolution, the mean value of the atom inversion operator 〈 S 3(t)〉 is gi ven. The influence of the “counter rotating term” on the collapse and revival phenomenon is discussed from the comparison between the cases with RWA and without RWA. It shows that the influence of the virtual photon field makes the quantum fluctuations appear on the collapse and revival phenomenon.展开更多
Approximate Dynamic Inversion (ADI) is basically an approximation of exact dynamic inversionor feedback linearisation, which converts a nonlinear system to an equivalent linear structure.This method can be widely appl...Approximate Dynamic Inversion (ADI) is basically an approximation of exact dynamic inversionor feedback linearisation, which converts a nonlinear system to an equivalent linear structure.This method can be widely applied for controlling minimum phase, nonaffine-in-control systems.For applying the ADI method, a fast dynamic subsystem for deriving explicit inversion of thenonaffine equation is required. With full state feedback, ADI may be expressed in the same way asa Proportional Integral (PI) controller with only knowledge of the sign of control effectiveness andalso without any approximation. The Model Reference Adaptive Controller (MRAC) augmentedwith the PI method is an adaptive control technique where the PI parameters are updated/tunedas per the control methodology based on the MRAC-Massachusetts Institute of Technology (MIT)rule so that the plant is capable to follow the reference model. The main objective of this paperis to find the relationship between ADI and MRAC augmented with a PI controller.展开更多
The nondestructive and rapid acquisition of rice field phenotyping information is very important for the precision management of the rice growth process.In this research,the phenotyping information LAI(leaf area index...The nondestructive and rapid acquisition of rice field phenotyping information is very important for the precision management of the rice growth process.In this research,the phenotyping information LAI(leaf area index),leaf chlorophyll content(C_(ab)),canopy water content(C_(w)),and dry matter content(C_(dm))of rice was inversed based on the hyperspectral remote sensing technology of an unmanned aerial vehicle(UAV).The improved Sobol global sensitivity analysis(GSA)method was used to analyze the input parameters of the PROSAIL model in the spectral band range of 400-1100 nm,which was obtained by hyperspectral remote sensing by the UAV.The results show that C_(ab) mainly affects the spectrum on 400-780 nm band,C_(dm) on 760-1000 nm band,C_(w) on 900-1100 nm band,and LAI on the entire band.The hyperspectral data of the 400-1100 nm band of the rice canopy were acquired by using the M600 UAV remote sensing platform,and the radiance calibration was converted to the canopy emission rate.In combination with the PROSAIL model,the particle swarm optimization algorithm was used to retrieve rice phenotyping information by constructing the cost function.The results showed the following:(1)an accuracy of R^(2)=0.833 and RMSE=0.0969,where RMSE denotes root-mean-square error,was obtained for C_(ab) retrieval;R^(2)=0.816 and RMSE=0.1012 for LAI inversion;R^(2)=0.793 and RMSE=0.1084 for C_(dm);and R^(2)=0.665 and RMSE=0.1325 for C_(w).The C_(w) inversion accuracy was not particularly high.(2)The same band will be affected by multiple parameters at the same time.(3)This study adopted the rice phenotyping information inversion method to expand the rice hyperspectral information acquisition field of a UAV based on the phenotypic information retrieval accuracy using a high level of field spectral radiometric accuracy.The inversion method featured a good mechanism,high universality,and easy implementation,which can provide a reference for nondestructive and rapid inversion of rice biochemical parameters using UAV hyperspectral remote sensing.展开更多
Hyper-spectral remote sensing may provide an effective solution to retrieve the methane （CH4） concentra- tion in an atmospheric column. As a result of exploring the absorptive characteristics of CH4, an appropriate ...Hyper-spectral remote sensing may provide an effective solution to retrieve the methane （CH4） concentra- tion in an atmospheric column. As a result of exploring the absorptive characteristics of CH4, an appropriate band is selected from hyperspectral data for the detection of its column concentration with high precision. Following the most recent inversion theory and methods, the line-by-line radiative transfer model （LBLRTM） is employed to forward model the impact of four sensitive factors on inversion precision, including CH4 initial profile, tempera- ture, overlapping gases, and surface albedo. The results indicate that the four optimized factors could improve the inversion precision of atmospheric CH4 column concen- tration.展开更多
In order to obtain the physical and geoacoustic properties of marine sediments,an inverse method using reflection loss of different grazing angles is presented.The reflection loss is calculated according to the reflec...In order to obtain the physical and geoacoustic properties of marine sediments,an inverse method using reflection loss of different grazing angles is presented.The reflection loss is calculated according to the reflection model of effective density fluid approximation.A two-step hybrid optimization algorithm combining differential evolution and particle swarm optimization along with Bayesian inversion is employed in estimation of porosity,mean grain size,mass density and bulk modulus of grains.Based on the above physical parameters,geoacoustic parameters,including sound speed and attenuation,are further calculated.According to the numerical simulations,we can draw a conclusion that all the parameters can be well estimated with the exception of bulk modulus of grains.In particular,this indirect inverse method for bottom geoacoustic parameters performs high accuracy and strong robustness.The relative errors are 0.092%and 17%,respectively.Finally,measured reflection loss data of sandy sediments at the bottom of a water tank is analyzed,and the estimation value,uncertainty and correlation of each parameter are presented.The availability of this inverse method is verified through comparison between inverse results and part of measured parameters.展开更多
This study addresses the parameter identification problem in a system of time-dependent quasi-linear partial differential equations(PDEs).Using the integral equation method,we prove the uniqueness of the inverse probl...This study addresses the parameter identification problem in a system of time-dependent quasi-linear partial differential equations(PDEs).Using the integral equation method,we prove the uniqueness of the inverse problem in nonlinear PDEs.Moreover,using the method of successive approximations,we develop a novel iterative algorithm to estimate sorption isotherms.The stability results of the algorithm are proven under both a priori and a posteriori stopping rules.A numerical example is given to show the efficiency and robustness of the proposed new approach.展开更多
基金Project(20110162120064)supported by Higher School Doctor Subject Special Scientific Research Foundation of ChinaProject(10JJ6059)supported by the Natural Science Foundation of Hunan Province,China
文摘How to get the rapid and stable inversion results and reconstruct the clear subsurface resistivity structures is a focus problem in current magnetotelluric inversion. A stable solution of an ill-posed inverse problem was obtained by the regularization methods in which some desired structures were imposed to stabilize the inverse problem. By the smoothness-constrained model and approximate sensitivity method, the stable subsurface resistivity structures were reconstructed. The synthetic examples show that the smoothness-constrained regularized inversion method is effective and can be reasonable to reconstruct three-dimensional subsurface resistivity structures.
文摘A class of general inverse matrix techniques based on adaptive algorithmic modelling methodologies is derived yielding iterative methods for solving unsymmetric linear systems of irregular structure arising in complex computational problems in three space dimensions. The proposed class of approximate inverse is chosen as the basis to yield systems on which classic and preconditioned iterative methods are explicitly applied. Optimized versions of the proposed approximate inverse are presented using special storage (k-sweep) techniques leading to economical forms of the approximate inverses. Application of the adaptive algorithmic methodologies on a characteristic nonlinear boundary value problem is discussed and numerical results are given.
文摘Full waveform inversion size of full waveform inversion will and the limitation of full waveform is mainly used to obtain high resolution velocity models of subsurface. The lead to a gigantic computation cost. Under the available computer resource inversion, the authors propose L-BFGS algorithm as the optimization method to solve this problem. In order to demonstrate the flexibility of the method, three different numerical experi- ments have been done to analyze the properties of full waveform inversion based on L-BFGS.
文摘The time evolution of system in two photon Jaynes Cummings (J C) model without rotating waves approximation (RWA) is obtained by using the theory of ordinary differential equations. Based on the evolution, the mean value of the atom inversion operator 〈 S 3(t)〉 is gi ven. The influence of the “counter rotating term” on the collapse and revival phenomenon is discussed from the comparison between the cases with RWA and without RWA. It shows that the influence of the virtual photon field makes the quantum fluctuations appear on the collapse and revival phenomenon.
文摘Approximate Dynamic Inversion (ADI) is basically an approximation of exact dynamic inversionor feedback linearisation, which converts a nonlinear system to an equivalent linear structure.This method can be widely applied for controlling minimum phase, nonaffine-in-control systems.For applying the ADI method, a fast dynamic subsystem for deriving explicit inversion of thenonaffine equation is required. With full state feedback, ADI may be expressed in the same way asa Proportional Integral (PI) controller with only knowledge of the sign of control effectiveness andalso without any approximation. The Model Reference Adaptive Controller (MRAC) augmentedwith the PI method is an adaptive control technique where the PI parameters are updated/tunedas per the control methodology based on the MRAC-Massachusetts Institute of Technology (MIT)rule so that the plant is capable to follow the reference model. The main objective of this paperis to find the relationship between ADI and MRAC augmented with a PI controller.
基金funded by the project‘Study on tomographic velocity inversion method based on P-wave and S-Wave constraints’(33550000-21-FW0399-0009)of State Key Laboratory of Shale Oil and Gas Enrichment Mechanisms and Effective Development and Sinopec Key Laboratory of Seismic Elastic Wave Technology.
基金support of the National Key Research and Development Plan of China(Grant No.2016YFD020060307)Key Project of Education Department of Liaoning province(LSNZD201605).
文摘The nondestructive and rapid acquisition of rice field phenotyping information is very important for the precision management of the rice growth process.In this research,the phenotyping information LAI(leaf area index),leaf chlorophyll content(C_(ab)),canopy water content(C_(w)),and dry matter content(C_(dm))of rice was inversed based on the hyperspectral remote sensing technology of an unmanned aerial vehicle(UAV).The improved Sobol global sensitivity analysis(GSA)method was used to analyze the input parameters of the PROSAIL model in the spectral band range of 400-1100 nm,which was obtained by hyperspectral remote sensing by the UAV.The results show that C_(ab) mainly affects the spectrum on 400-780 nm band,C_(dm) on 760-1000 nm band,C_(w) on 900-1100 nm band,and LAI on the entire band.The hyperspectral data of the 400-1100 nm band of the rice canopy were acquired by using the M600 UAV remote sensing platform,and the radiance calibration was converted to the canopy emission rate.In combination with the PROSAIL model,the particle swarm optimization algorithm was used to retrieve rice phenotyping information by constructing the cost function.The results showed the following:(1)an accuracy of R^(2)=0.833 and RMSE=0.0969,where RMSE denotes root-mean-square error,was obtained for C_(ab) retrieval;R^(2)=0.816 and RMSE=0.1012 for LAI inversion;R^(2)=0.793 and RMSE=0.1084 for C_(dm);and R^(2)=0.665 and RMSE=0.1325 for C_(w).The C_(w) inversion accuracy was not particularly high.(2)The same band will be affected by multiple parameters at the same time.(3)This study adopted the rice phenotyping information inversion method to expand the rice hyperspectral information acquisition field of a UAV based on the phenotypic information retrieval accuracy using a high level of field spectral radiometric accuracy.The inversion method featured a good mechanism,high universality,and easy implementation,which can provide a reference for nondestructive and rapid inversion of rice biochemical parameters using UAV hyperspectral remote sensing.
文摘Hyper-spectral remote sensing may provide an effective solution to retrieve the methane （CH4） concentra- tion in an atmospheric column. As a result of exploring the absorptive characteristics of CH4, an appropriate band is selected from hyperspectral data for the detection of its column concentration with high precision. Following the most recent inversion theory and methods, the line-by-line radiative transfer model （LBLRTM） is employed to forward model the impact of four sensitive factors on inversion precision, including CH4 initial profile, tempera- ture, overlapping gases, and surface albedo. The results indicate that the four optimized factors could improve the inversion precision of atmospheric CH4 column concen- tration.
基金supported by the National Nature Science Foundation of China(11274078,11234002)
文摘In order to obtain the physical and geoacoustic properties of marine sediments,an inverse method using reflection loss of different grazing angles is presented.The reflection loss is calculated according to the reflection model of effective density fluid approximation.A two-step hybrid optimization algorithm combining differential evolution and particle swarm optimization along with Bayesian inversion is employed in estimation of porosity,mean grain size,mass density and bulk modulus of grains.Based on the above physical parameters,geoacoustic parameters,including sound speed and attenuation,are further calculated.According to the numerical simulations,we can draw a conclusion that all the parameters can be well estimated with the exception of bulk modulus of grains.In particular,this indirect inverse method for bottom geoacoustic parameters performs high accuracy and strong robustness.The relative errors are 0.092%and 17%,respectively.Finally,measured reflection loss data of sandy sediments at the bottom of a water tank is analyzed,and the estimation value,uncertainty and correlation of each parameter are presented.The availability of this inverse method is verified through comparison between inverse results and part of measured parameters.
基金supported by the National Natural Science Foundation of China(No.12171036)Beijing Natural Science Foundation(No.Z210001)the NSF of China No.11971221,Guangdong NSF Major Fund No.2021ZDZX1001,the Shenzhen Sci-Tech Fund Nos.RCJC20200714114556020,JCYJ20200109115422828 and JCYJ20190809150413261,National Center for Applied Mathematics Shenzhen,and SUSTech International Center for Mathematics.
文摘This study addresses the parameter identification problem in a system of time-dependent quasi-linear partial differential equations(PDEs).Using the integral equation method,we prove the uniqueness of the inverse problem in nonlinear PDEs.Moreover,using the method of successive approximations,we develop a novel iterative algorithm to estimate sorption isotherms.The stability results of the algorithm are proven under both a priori and a posteriori stopping rules.A numerical example is given to show the efficiency and robustness of the proposed new approach.
