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Reflection full-waveform inversion using a modified phase misfit function
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作者 崔超 黄建平 +2 位作者 李振春 廖文远 关哲 《Applied Geophysics》 SCIE CSCD 2017年第3期407-418,461,共13页
Reflection full-waveform inversion (RFWI) updates the low- and high- wavenumber components, and yields more accurate initial models compared with conventional full-waveform inversion (FWI). However, there is stron... Reflection full-waveform inversion (RFWI) updates the low- and high- wavenumber components, and yields more accurate initial models compared with conventional full-waveform inversion (FWI). However, there is strong nonlinearity in conventional RFWI because of the lack of low-frequency data and the complexity of the amplitude. The separation of phase and amplitude information makes RFWI more linear. Traditional phase-calculation methods face severe phase wrapping. To solve this problem, we propose a modified phase-calculation method that uses the phase-envelope data to obtain the pseudo phase information. Then, we establish a pseudophase-information-based objective function for RFWI, with the corresponding source and gradient terms. Numerical tests verify that the proposed calculation method using the phase-envelope data guarantees the stability and accuracy of the phase information and the convergence of the objective function. The application on a portion of the Sigsbee2A model and comparison with inversion results of the improved RFWI and conventional FWI methods verify that the pseudophase-based RFWI produces a highly accurate and efficient velocity model. Moreover, the proposed method is robust to noise and high frequency. 展开更多
关键词 Reflection full-waveform inversion full-waveform inversion misfit function
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基于核密度估计的中国海洋经济发展动态演变 被引量:49
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作者 孙才志 李欣 《经济地理》 CSSCI 北大核心 2015年第1期96-103,共8页
通过构建人均海洋产值和海岸线经济密度的核密度函数模型与基尼系数,以我国沿海11个省份为例,利用2000—2012年的数据描绘了海洋经济发展的动态演变趋势与规律,并利用基尼系数对其进行空间分析。通过核密度函数分解得出我国海洋经济发... 通过构建人均海洋产值和海岸线经济密度的核密度函数模型与基尼系数,以我国沿海11个省份为例,利用2000—2012年的数据描绘了海洋经济发展的动态演变趋势与规律,并利用基尼系数对其进行空间分析。通过核密度函数分解得出我国海洋经济发展动态是呈单峰分布的,在人均海洋产值年度差异分解中,占据主导地位的是均值效应,多年平均值为88.79%,其次是方差效应,多年平均值为11.21%;在海岸线经济密度年度差异分解中,占据主导地位的仍是均值效应,多年平均值为86.91%,其次为方差效应,多年平均值为13.09%,由此可见,均值效应与年度差异分布总效应的方向基本相同。通过基尼系数,从空间维度评价不同年度的空间差异,并通过基尼系数差值与方差效应进行对比分析,从而在时空两个维度上全面刻画我国沿海地区海洋经济发展的动态演变规律。 展开更多
关键词 信息扩散 密度函数分解 基尼系数 人均海洋产值 海岸线经济密度 中国
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L^p Estimates for Singular Radon Transforms with Rough Kernels
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作者 Zhenqiu ZHANG Meifang CHENG 《Chinese Annals of Mathematics,Series B》 SCIE CSCD 2008年第2期155-164,共10页
The purpose of this paper is to study the mapping properties of the singular Radon transforms with rough kernels. Such singular integral operators are proved to be bounded on Lebesgue spaces.
关键词 Singular Radon transform Rough kernel Dyadic decomposition
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Optimality conditions for sparse nonlinear programming 被引量:7
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作者 PAN LiLi XIU NaiHua FAN Jun 《Science China Mathematics》 SCIE CSCD 2017年第5期759-776,共18页
The sparse nonlinear programming (SNP) is to minimize a general continuously differentiable func- tion subject to sparsity, nonlinear equality and inequality constraints. We first define two restricted constraint qu... The sparse nonlinear programming (SNP) is to minimize a general continuously differentiable func- tion subject to sparsity, nonlinear equality and inequality constraints. We first define two restricted constraint qualifications and show how these constraint qualifications can be applied to obtain the decomposition properties of the Frechet, Mordukhovich and Clarke normal cones to the sparsity constrained feasible set. Based on the decomposition properties of the normal cones, we then present and analyze three classes of Karush-Kuhn- Tucker (KKT) conditions for the SNP. At last, we establish the second-order necessary optimality condition and sufficient optimality condition for the SNP. 展开更多
关键词 sparse nonlinear programming constraint qualification normal cone first-order optimality con-dition second-order optimality condition
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