Xun Wang

Xun Wang
Central South University | CSU · School of Geoscience and Info-Physics

PhD

About

35
Publications
2,800
Reads
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142
Citations
Introduction
My research interests include the numerical modeling of electromagnetic waves and the full waveform inversion of ground-penetrating radar.
Additional affiliations
March 2021 - present
Central South University
Position
  • PhD
Education
September 2016 - July 2020
Central South University
Field of study
  • Applied Geophysics

Publications

Publications (35)
Article
Full-text available
Complex Frequency-Shifted PML in the long time domain has good absorption effect about litter wave and prosperous lost wave, and is widely used in FDTD simulation. In this paper, the convolution makes CFS-PML apply in the finite element time domain solution numerical of simulation GPR wave equation. In TM wave as an example, in this paper we deduce...
Article
Irregular and complicated tunnel lining defects cannot be finely depicted with the standard finite difference simulation method based on regular mesh due to its irregular geometrical characteristics and complex physical properties of various defects. To solve this problem, a new hybrid algorithm is proposed for all-refined ground penetrating radar...
Article
Full-text available
The time domain full waveform inversion (FWI) of ground penetrating radar (GPR) is difficult to calculate on personal computer due to its calculation and high memory requirements. In this paper, we use the optimized conjugate gradient method based on the GPU parallel acceleration with the dimensionality lifting scheme, and the calculation of Hessia...
Article
Complex irregular defects of tunnel linings under complicated geological conditions cannot be accurately reconstructed with the traditional full-waveform inversion (FWI) method due to their irregular geometrical characteristics and complex dielectric properties. Because of extensive inversion calculations and high memory requirements, the tradition...
Article
Full-waveform inversion (FWI) in the time domain of ground-penetrating radar (GPR) data involves a vast number of calculations; thus, it requires a large amount of memory and is difficult to calculate on a personal computer (PC). In this paper, GPR data are analyzed with multiscale FWI using two parameters (permittivity and conductivity) based on t...
Article
Horizontally transverse isotropy (HTI) induced by vertical or subvertical, aligned fractures is common for unconventional fractured porous shale oil or gas reservoirs. Compared with the unfractured rocks, the seismic response characteristics of PP-wave azimuthal amplitudes are usually disturbed by the fractures and the in-situ stresses. Knowledge o...
Article
The finite element time-domain (FETD) method is an appealing electromagnetic (EM) field-solving procedure for the derivation of high-resolution field distribution of complex geological models. However, the arising computational burden has become a main bottleneck restricting the efficient implementation of ground penetrating radar (GPR) simulation...
Article
Full-text available
High-precision detection of the underground pipelines is an indispensable part of the development and construction of cities. At present, the inversion technology for ground-penetrating radar (GPR) data is an effective means of realizing shallow-underground-space visualization in the field of geophysical exploration. However, the traditional full-w...
Article
Reverse time migration (RTM) is the important intermediate step for focusing the radar diffracted energy of the targets in ground penetrating radar imaging. The conventional RTM algorithm demands a large number of iterative trial experiments and depends on the experts' decision on the estimation of the velocity or relative permittivity of the subsu...
Article
Accurate location and depth determination of underground pipes, especially the attribute recognition, are of great importance yet remake a challenging issue in municipal environments. Single-trace phase difference analysis remains a bottleneck due to its inherent and strong randomness in object identification. This paper developed a multi-trace pha...
Article
Full-text available
The ground penetrating radar (GPR) data in the complex detection environment is non-stationary, non-Gaussian, and non-uniform, so the traditional noise attenuation methods are difficult to meet the requirements of denoising. Therefore, we introduced the K-singular value decomposition (K-SVD) dictionary learning into the denoising of GPR signals. It...
Article
The full-waveform inversion (FWI) of ground-penetrating radar (GPR) data yields promise for quantitatively characterizing the parameters of the Earth's shallow subsurface. However, conventional FWI is highly nonlinear and suffers from cycle skipping once the low-frequency data are missed or the initial model is poor. Furthermore, having limited pri...
Article
Full-text available
The high-fidelity attenuation of random ground penetrating radar (GPR) noise is important for enhancing the signal-noise ratio (SNR). In this paper, a novel network structure for convolutional denoising autoencoders (CDAEs) was proposed to effectively resolve various problems in the noise attenuation process, including overfitting, the size of the...
Article
Ground-penetrating radar (GPR) full-waveform inversion (FWI) is an emerging near-surface high-resolution imaging technology that has been widely used in GPR 2-D imaging to better quantitatively evaluate the permittivity and conductivity of the subsurface. However, the 2-D imaging method limits the applicability and accuracy of FWI for the 3-D objec...
Article
Full waveform inversion (FWI) of ground-penetrating radar (GPR) data is becoming a promising technique to facilitate the interpretation of surface-GPR data and the mapping of the subsurface. However, more general FWIs still require a sufficient amount of RAM memory, and it is difficult to produce an accurate and representative reconstruction result...
Conference Paper
Full-text available
Full waveform inversion (FWI) is one of the most promising techniques for the quantitative characterization of the shallow subsurface of the Earth. However, the conventional FWI with the reduced approach is highly nonlinear, a challenging source of which is the cycle skipping. It would drive FWI to spurious local minima as soon as the initial model...
Article
Full-text available
The dual-parameter Full Waveform Inversion (FWI) of Ground Penetrating Radar (GPR) needs a vast amount of calculation and can easily fall into a local minimum. In addition, the crosstalk noise caused by coupling the permittivity and conductivity can affect the accuracy of the inversion for conductivity. To solve these problems, this study introduce...
Article
Accurate and efficient 3D simulation is extremely important for both grasping the features of radar wave propagation in realistic models and the high-resolution inversion. In this paper, we propose a new numerical algorithm called the low-storage five-stage fourth-order explicit Runge-Kutta interpolation scaling function method (LSERK-ISFM) and app...
Article
The conductivity distribution of subsurface often contains segmented structure with sharp interfaces, although the magnetotelluric (MT) inversions based on Tikhonov regularization are usually stable, the smoothing interfaces tomography result from high-resistance artifacts and boundary blurring still post a great challenge for MT inversion. On the...
Article
To address problems, such as the computationally intensive inversion requirements, low inversion efficiency, and inadequate inversion accuracy caused by multiparameter cross-talk in a synchronous inversion, a new dynamic stochastic source encoding strategy combined with minmax-concave total variation (MCTV) regularization model constraints was prop...
Article
Ground-penetrating radar (GPR) is a highly efficient, fast and non-destructive exploration method for shallow surfaces. High-precision numerical simulation method is employed to improve the interpretation precision of detection. Second-generation wavelet finite element is introduced into the forward modeling of the GPR. As the finite element basis...
Article
We present a new approach of unstructured grid adaptive finite element in the frequency domain (AFEFD) based on exact perfect matching layer (EPML) boundary condition for Ground penetrating radar (GPR) simulation. The discrete equations of transverse magnetic mode are derived by using the unstructured Delaunay mesh coupled with linear interpolation...
Article
Investigation into the electromagnetic response of porous media and the porosity distribution is a key for improved porous material. However, current ground penetrating radar (GPR) simulation techniques based on the finite difference method (FDM) or even finite element method (FEM) are mainly focused on describing macro characteristics of porous pr...
Article
Full-text available
One of the great challenges of unconfined seepage through a dam lies in the accurate determination of free surface that depends on the complexity of the seepage model, especially if the model is characterized with complex geometry and sharp variations in permeability distribution. This study presents a practical methodology that combines the adapti...
Article
Full-text available
In this work, an interpolating wavelet is constructed by the lifting scheme of the second generation wavelet transformation, by employing the two-dimensional wavelet transform into the wave field function of radar, both the wavelet coefficients and scale coefficients that corresponding to the computational grid of different scales can be all calcul...
Article
Based on the variational problem derived from magnetotelluric(MT) boundary value problems, the finite element method using irregular quadrilateral mesh and bilinear interpolation was used to solve MT forward problem of steep topography model. The detailed calculation of Jacobi transformation matrix was discussed and interpolation method of arbitrar...
Article
Full-text available
This article introduces the principle of CPML boundary conditions, and deduces its FDTD formula for GPR forward modeling, and then compares and analyzes the absorption properties of evanescent wave in Berenger PML, UPML, CPML. The numerical experiment of key parameters κ and α in PML were performed so as to determine its range and selection princip...
Article
Starting from the Maxwell equations, this article studied the boundary conditions of 3D MT. By using the weighted residual method, we derived the three-dimensional MT finite element equation. The three-dimensional vector finite element hexahedral meshing mode was introduced and the basis functions were selected. Then we derived the three-dimensiona...
Article
Full-text available
Based on the separable wavelet theory,the scaling functions of one-dimensional Bspline wavelet on the interval(BSWI)is employed to construct the two-dimensional B-spline wavelet bases on the interval.In order to solve the GPR wave equation,these constructed wavelet bases are used as the interpolation functions,and a transformation matrix is introdu...
Article
Full-text available
Ground penetrating radar (GPR) forward is one of the geophysical research directions. Through the forward of geological model, the database of radar model can be enriched and the characteristics of typical geological radar echo images can be understood, which in turn can guide the data interpretation of GPR measured profile, thereby improving the G...
Article
Based on the separable wavelet theory, we construct the two-dimensional Daubechies wavelet bases by means of one-dimensional Daubechies scaling functions, which is used for interpolation functions of solving the GPR wave equation, thus present the discrete format of two-dimensional Daubechies wavelet finite element GPR equation. By introducing a tr...
Article
Considering that Daubechies wavelet finite element connection coefficient is calculated by adding complex equations currently, calculation results vary with different numbers of additional equations with high difficulty, and calculation results are not precise enough, the compound trapezoid quadrature method (CTQM) was combined with filter coeffici...
Article
Full-text available
Based on the boundary value problem of partial differential equation of the two-dimensional magnetotelluric (MT) forward modeling meet, the detail algorithm of finite element method deduced by the rectangular grid subdivision and cell biquadratic interpolation method were used to solve the electromagnetic problems both in TE and TM polarization mod...

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Projects

Projects (3)
Project
GPR full-waveform inversion
Project
GPR forward modeling