The transformation of the magnetization direction and the magnetic fi eld component is one of the important methods in magnetic data processing and transformation,which can be conducted in both wavenumber and spatial ...The transformation of the magnetization direction and the magnetic fi eld component is one of the important methods in magnetic data processing and transformation,which can be conducted in both wavenumber and spatial domains.The transformation method in the wavenumber domain has simpler processing expression and higher processing effi ciency than in the spatial domain;however,they are unstable at low latitude.In this paper,the conclusion that the sum is 0 of two vertical magnetic fi eld components(magnetization inclinations are also perpendicular)in 2D is used for the 3D transformation of the magnetization direction and the magnetic field component.In addition,the transformation method at low latitudes based on vertical relationship(VMT)is proposed,which is an iterative algorithm that converts the transformation of the magnetization direction and the magnetic field component at the low latitude into the high latitude.This method restrains the instability of transformation of constant and variable magnetization direction and magnetic fi eld components in low latitudes.The accuracy,stability,and practicality are verifi ed from synthetic models and real data.展开更多
GNSS(global navigation satellite system)observations produce the geodetic position including latitude,longitude,and altitude(or ellipsoidal height)concerning the global reference datum WGS84(Word Geodetic System 1984)...GNSS(global navigation satellite system)observations produce the geodetic position including latitude,longitude,and altitude(or ellipsoidal height)concerning the global reference datum WGS84(Word Geodetic System 1984),which usually should be converted to another local datum to get the desired position meaning in a physical sense,coordinates of points in the local datum are usually calculated by the seven-parameter transformation method.This paper aims to validate the methods of position transformation between WGS84 and the Iraqi local datum Karbala 1979 using the UTM(universal transverse Mercator)projected coordinates directly.The proposed algorithm was tested for 10 ground control points in Erbil city and many selected points in other different cities over all Iraqi territory.The control points are measured by the CHCNAV i73 GNSS receiver.For the evaluation procedure,the RMSE(root mean square error)of the transformed coordinates is calculated with an average value of±10.715 m as an estimated uncertainty of the direct UTM coordinates transformation method over Erbil city territory,and more than±12 m over different places over Iraqi territory.展开更多
Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transform...Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation （DLT） and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.展开更多
There are two aspects in the study of irregular mixed-layer clay minerals: one is the kinds and ratios of their basic structural unit layers and the other is the junction probabilities of the unit layers. Irregular mi...There are two aspects in the study of irregular mixed-layer clay minerals: one is the kinds and ratios of their basic structural unit layers and the other is the junction probabilities of the unit layers. Irregular mixed-layer illite/smectite clay minerals (I/S) are widespread in nature. While studying the clay minerals from the Permian-Triassic (P/T) boundary bed, the authors found that I/S clay minerals are developed in all P/T boundary clay layers in areas from the northwest to southeast of China. Systematic mineralogical studies of the I/S clay minerals from Hunan, Hubei, Sichuan and Zhejiang were made by means of X-ray, infrared spectroscopic, electron microscopic and chemical analyses and a deepened study of the stacking sequences of their structural unit layers was conducted by the MacEwan one—dimentional direct Fourier transform. It was found that the stacking of the illite and smectite crystal layers along the c axis can be derived from Fibonacci sequences. Hence, the authors propose that such I/S clay minerals are possessed of two—dimentional crystal lattice and one—dimentional quasicrystal lattice.展开更多
Calcium sulfate hemihydrate （CSH） whiskers were synthesized by phase transition in CaCl2 solution under atmospheric pressure. Analytical-grade calcium sulfate dihydrate （AR CSD） was used as the raw material for th...Calcium sulfate hemihydrate （CSH） whiskers were synthesized by phase transition in CaCl2 solution under atmospheric pressure. Analytical-grade calcium sulfate dihydrate （AR CSD） was used as the raw material for the synthesis of CSH whiskers, according to orthogonal experiments. The effects of reaction tem- perature, AR CSD content, H2SO4 content, and reaction time were investigated, and the crystallization conditions were optimized. The as-prepared CSH whiskers displayed a regular morphology and a highly uniform size, with an aspect ratio of 105, A simulation system was also established by blending various sulfates with AR CSD, to evaluate the effects of impurities in flue gas desulfurization （FGD） gypsum. The main aim was to prepare CSH whiskers directly from FGD gypsum, without any purification, using the optimized conditions. This is a facile potential alternative process for large-scale production of CSH whiskers using abundant FGD gypsum as source materials.展开更多
Loop transformations, such as loop interchange, reversal and skewing, have been unified under linear matrix transformations. A legal transformation matrix is usually generated based upon distance vectors or direction ...Loop transformations, such as loop interchange, reversal and skewing, have been unified under linear matrix transformations. A legal transformation matrix is usually generated based upon distance vectors or direction vectors. Unfortunately, for some nested loops, distance vectors may not be computable and direction vectors, on the other hand, may not contain useful information. We propose the use of linear equations or inequalities of distance vectors to approximate data dependence. This approach is advantageous since (1) many loops having no constant distance vectors have very simple equations of distance vectors; (2) these equations contain more information than direction vectors do, thus the cliance of exploiting potential parallelism is improved.In general, the equations or inequalities that approximate the data dependence of a given nested loop is not unique, hence classification is discussed for the purpose of loop transformation. Efficient algorithms are developed to generate all kinds of linear equations of distance vectors for a given nested loop. The issue of how to obtain a desired transformation matrix from those equations is also addressed.展开更多
In this paper, a sampling adaptive for block compressed sensing with smooth projected Landweber based on edge detection （SA-BCS-SPL-ED） image reconstruction algorithm is presented. This algorithm takes full advantag...In this paper, a sampling adaptive for block compressed sensing with smooth projected Landweber based on edge detection （SA-BCS-SPL-ED） image reconstruction algorithm is presented. This algorithm takes full advantage of the characteristics of the block compressed sensing, which assigns a sampling rate depending on its texture complexity of each block. The block complexity is measured by the variance of its texture gradient, big variance with high sampling rates and small variance with low sampling rates. Meanwhile, in order to avoid over-sampling and sub-sampling, we set up the maximum sampling rate and the minimum sampling rate for each block. Through iterative algorithm, the actual sampling rate of the whole image approximately equals to the set up value. In aspects of the directional transforms, discrete cosine transform （DCT）, dual-tree discrete wavelet transform （DDWT）, discrete wavelet transform （DWT） and Contourlet （CT） are used in experiments. Experimental results show that compared to block compressed sensing with smooth projected Landweber （BCS-SPL）, the proposed algorithm is much better with simple texture images and even complicated texture images at the same sampling rate. Besides, SA-BCS-SPL-ED-DDWT is quite good for the most of images while the SA-BCS-SPL-ED-CT is likely better only for more-complicated texture images.展开更多
Metro tunnels play a crucial role in urban transportation.However,with growing tunnel operation periods,defects,and large deformations appearing,these are influencing tunnel structural performance and threatening publ...Metro tunnels play a crucial role in urban transportation.However,with growing tunnel operation periods,defects,and large deformations appearing,these are influencing tunnel structural performance and threatening public safety.Three-dimensional(3D)tunnel reconstruction is an effective way to highlight tunnel conditions and provide a basis for engineering management and maintenance.However,the current methods of tunnel 3D reconstruction do not sufficiently combine the qualitative and quantitative characteristics of tunnel states.In this study,a novel method for metro tunnel 3D reconstruction based on structure from motion(SfM)and direct linear transformation(DLT)is proposed.The dimensionless 3D reconstruction point cloud acquired through the SfM method showcases the qualitative characteristics(such as leakage and pipelines)of the tunnel state.The close-range photogrammetry DLT method provides scale information missing from the SfM method and quantitative characteristics(such as profile deformation)of the tunnel state.The SfM-DLT method was tested in a Shanghai metro tunnel,and proved to be feasible and promising for future tunnel inspections.展开更多
Growing electric power demand and the consumption of large-scale renewable energy require a more efficient power supply network,with less occupied areas in load centers.In this paper,application principles of power su...Growing electric power demand and the consumption of large-scale renewable energy require a more efficient power supply network,with less occupied areas in load centers.In this paper,application principles of power supply network based on 500/110 kV direct transformation are proposed.An in-depth analysis of the grid structure and substation design is presented along with an application scenario.An accessibility index based on power flow tracing for network evaluation is also proposed.The index is able to present the inner connectivity and power transferability of a power network.A comprehensive evaluation of traditional short circuit,load flow,N-1,economic calculation,and the accessibility index are conducted on the power grid planning of a high-tech industrial park in Wuhan,China.Finally,electric feasibility and reliability are validated,and accessibility and construction investments compared.展开更多
基金supported by the subject“Study on the Comprehensive Processing and Interpretation Method and Software Development for Aerial Geophysics(No.2017YFC0602202)”from National major Research and Development Project of China(No.2017YFC0602200)。
文摘The transformation of the magnetization direction and the magnetic fi eld component is one of the important methods in magnetic data processing and transformation,which can be conducted in both wavenumber and spatial domains.The transformation method in the wavenumber domain has simpler processing expression and higher processing effi ciency than in the spatial domain;however,they are unstable at low latitude.In this paper,the conclusion that the sum is 0 of two vertical magnetic fi eld components(magnetization inclinations are also perpendicular)in 2D is used for the 3D transformation of the magnetization direction and the magnetic field component.In addition,the transformation method at low latitudes based on vertical relationship(VMT)is proposed,which is an iterative algorithm that converts the transformation of the magnetization direction and the magnetic field component at the low latitude into the high latitude.This method restrains the instability of transformation of constant and variable magnetization direction and magnetic fi eld components in low latitudes.The accuracy,stability,and practicality are verifi ed from synthetic models and real data.
文摘GNSS(global navigation satellite system)observations produce the geodetic position including latitude,longitude,and altitude(or ellipsoidal height)concerning the global reference datum WGS84(Word Geodetic System 1984),which usually should be converted to another local datum to get the desired position meaning in a physical sense,coordinates of points in the local datum are usually calculated by the seven-parameter transformation method.This paper aims to validate the methods of position transformation between WGS84 and the Iraqi local datum Karbala 1979 using the UTM(universal transverse Mercator)projected coordinates directly.The proposed algorithm was tested for 10 ground control points in Erbil city and many selected points in other different cities over all Iraqi territory.The control points are measured by the CHCNAV i73 GNSS receiver.For the evaluation procedure,the RMSE(root mean square error)of the transformed coordinates is calculated with an average value of±10.715 m as an estimated uncertainty of the direct UTM coordinates transformation method over Erbil city territory,and more than±12 m over different places over Iraqi territory.
基金Project 2005A030 supported by the Youth Science and Research Foundation from China University of Mining & Technology
文摘Camera calibration is a critical process in photogrammetry and a necessary step to acquire 3D information from a 2D image. In this paper, a flexible approach for CCD camera calibration using 2D direct linear transformation （DLT） and bundle adjustment is proposed. The proposed approach assumes that the camera interior orientation elements are known, and addresses a new closed form solution in planar object space based on homogenous coordinate representation and matrix factorization. Homogeneous coordinate representation offers a direct matrix correspondence between the parameters of the 2D DLT and the collinearity equation. The matrix factorization starts by recovering the elements of the rotation matrix and then solving for the camera position with the collinearity equation. Camera calibration with high precision is addressed by bundle adjustment using the initial values of the camera orientation elements. The results show that the calibration precision of principal point and focal length is about 0.2 and 0.3 pixels respectivelv, which can meet the requirements of close-range photogrammetry with high accuracy.
基金A project supported by the National Natural Science Foundation of China (No. 4880082).
文摘There are two aspects in the study of irregular mixed-layer clay minerals: one is the kinds and ratios of their basic structural unit layers and the other is the junction probabilities of the unit layers. Irregular mixed-layer illite/smectite clay minerals (I/S) are widespread in nature. While studying the clay minerals from the Permian-Triassic (P/T) boundary bed, the authors found that I/S clay minerals are developed in all P/T boundary clay layers in areas from the northwest to southeast of China. Systematic mineralogical studies of the I/S clay minerals from Hunan, Hubei, Sichuan and Zhejiang were made by means of X-ray, infrared spectroscopic, electron microscopic and chemical analyses and a deepened study of the stacking sequences of their structural unit layers was conducted by the MacEwan one—dimentional direct Fourier transform. It was found that the stacking of the illite and smectite crystal layers along the c axis can be derived from Fibonacci sequences. Hence, the authors propose that such I/S clay minerals are possessed of two—dimentional crystal lattice and one—dimentional quasicrystal lattice.
基金financially supported by the Shanghai Foundation of Excellent Young University Teachersthe Science and Technology Commission of Shanghai Municipality(13ZR1415100,13JC1402700,14195800600)the Science and Technology Development Fund of Pudong New Area(PKJ2012-C05)
文摘Calcium sulfate hemihydrate （CSH） whiskers were synthesized by phase transition in CaCl2 solution under atmospheric pressure. Analytical-grade calcium sulfate dihydrate （AR CSD） was used as the raw material for the synthesis of CSH whiskers, according to orthogonal experiments. The effects of reaction tem- perature, AR CSD content, H2SO4 content, and reaction time were investigated, and the crystallization conditions were optimized. The as-prepared CSH whiskers displayed a regular morphology and a highly uniform size, with an aspect ratio of 105, A simulation system was also established by blending various sulfates with AR CSD, to evaluate the effects of impurities in flue gas desulfurization （FGD） gypsum. The main aim was to prepare CSH whiskers directly from FGD gypsum, without any purification, using the optimized conditions. This is a facile potential alternative process for large-scale production of CSH whiskers using abundant FGD gypsum as source materials.
文摘Loop transformations, such as loop interchange, reversal and skewing, have been unified under linear matrix transformations. A legal transformation matrix is usually generated based upon distance vectors or direction vectors. Unfortunately, for some nested loops, distance vectors may not be computable and direction vectors, on the other hand, may not contain useful information. We propose the use of linear equations or inequalities of distance vectors to approximate data dependence. This approach is advantageous since (1) many loops having no constant distance vectors have very simple equations of distance vectors; (2) these equations contain more information than direction vectors do, thus the cliance of exploiting potential parallelism is improved.In general, the equations or inequalities that approximate the data dependence of a given nested loop is not unique, hence classification is discussed for the purpose of loop transformation. Efficient algorithms are developed to generate all kinds of linear equations of distance vectors for a given nested loop. The issue of how to obtain a desired transformation matrix from those equations is also addressed.
基金supported by the National Natural Science Foundation of China (61071091, 61071166)the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institution-Information and Communication Engineering
文摘In this paper, a sampling adaptive for block compressed sensing with smooth projected Landweber based on edge detection （SA-BCS-SPL-ED） image reconstruction algorithm is presented. This algorithm takes full advantage of the characteristics of the block compressed sensing, which assigns a sampling rate depending on its texture complexity of each block. The block complexity is measured by the variance of its texture gradient, big variance with high sampling rates and small variance with low sampling rates. Meanwhile, in order to avoid over-sampling and sub-sampling, we set up the maximum sampling rate and the minimum sampling rate for each block. Through iterative algorithm, the actual sampling rate of the whole image approximately equals to the set up value. In aspects of the directional transforms, discrete cosine transform （DCT）, dual-tree discrete wavelet transform （DDWT）, discrete wavelet transform （DWT） and Contourlet （CT） are used in experiments. Experimental results show that compared to block compressed sensing with smooth projected Landweber （BCS-SPL）, the proposed algorithm is much better with simple texture images and even complicated texture images at the same sampling rate. Besides, SA-BCS-SPL-ED-DDWT is quite good for the most of images while the SA-BCS-SPL-ED-CT is likely better only for more-complicated texture images.
基金supported by the Science and Technology Commission of Shanghai Municipality(Grant No.18DZ1205902)the Key innovation team program of innovation talents promotion plan by MOST of China(No.2016RA4059)the National Key R&D Program of China(Grant No.2018YFB2101000).
文摘Metro tunnels play a crucial role in urban transportation.However,with growing tunnel operation periods,defects,and large deformations appearing,these are influencing tunnel structural performance and threatening public safety.Three-dimensional(3D)tunnel reconstruction is an effective way to highlight tunnel conditions and provide a basis for engineering management and maintenance.However,the current methods of tunnel 3D reconstruction do not sufficiently combine the qualitative and quantitative characteristics of tunnel states.In this study,a novel method for metro tunnel 3D reconstruction based on structure from motion(SfM)and direct linear transformation(DLT)is proposed.The dimensionless 3D reconstruction point cloud acquired through the SfM method showcases the qualitative characteristics(such as leakage and pipelines)of the tunnel state.The close-range photogrammetry DLT method provides scale information missing from the SfM method and quantitative characteristics(such as profile deformation)of the tunnel state.The SfM-DLT method was tested in a Shanghai metro tunnel,and proved to be feasible and promising for future tunnel inspections.
基金supported in part by the National Natural Science Foundation of China under Grant 51277082in part by Huang He Ying Cai Funding of Wuhanin part by State Grid Hubei Electric Power Company.
文摘Growing electric power demand and the consumption of large-scale renewable energy require a more efficient power supply network,with less occupied areas in load centers.In this paper,application principles of power supply network based on 500/110 kV direct transformation are proposed.An in-depth analysis of the grid structure and substation design is presented along with an application scenario.An accessibility index based on power flow tracing for network evaluation is also proposed.The index is able to present the inner connectivity and power transferability of a power network.A comprehensive evaluation of traditional short circuit,load flow,N-1,economic calculation,and the accessibility index are conducted on the power grid planning of a high-tech industrial park in Wuhan,China.Finally,electric feasibility and reliability are validated,and accessibility and construction investments compared.
