In this article, numerical modeling of borehole radar for well logging in time domain is developed using pseudo-spectral time domain algorithm in axisymmetric cylindrical coordinate for proximate true formation model....In this article, numerical modeling of borehole radar for well logging in time domain is developed using pseudo-spectral time domain algorithm in axisymmetric cylindrical coordinate for proximate true formation model. The conductivity and relative permittivity logging curves are obtained from the data of borehole radar for well logging. Since the relative permittivity logging curve is not affected by salinity of formation water, borehole radar for well logging has obvious advantages as compared with conventional electrical logging. The borehole radar for well logging is a one-transmitter and two-receiver logging tool. The conductivity and relative permittivity logging curves are obtained successfully by measuring the amplitude radio and the time difference of pulse waveform from two receivers. The calculated conductivity and relative permittivity logging curves are close to the true value of surrounding formation, which tests the usability and reliability of borehole radar for well logging. The numerical modeling of borehole radar for well logging laid the important foundation for researching its logging tool.展开更多
数码管图像的目标和背景分离不明显,直方图分布较复杂。针对该问题,提出基于拉普拉斯高斯(Laplacian of Gaussian,LoG)算子边缘检测的全局二值化方法对其进行处理,该方法通过提取图像边缘部份的像素灰度获得图像二值化的阈值。处理结果...数码管图像的目标和背景分离不明显,直方图分布较复杂。针对该问题,提出基于拉普拉斯高斯(Laplacian of Gaussian,LoG)算子边缘检测的全局二值化方法对其进行处理,该方法通过提取图像边缘部份的像素灰度获得图像二值化的阈值。处理结果表明,与传统的几种方法相比,该方法能够快速选取良好的二值化阈值,较好地区分目标和背景,在相当大模板宽度内图像二值化的结果都令人满意。展开更多
该文研究近似Log-M AP算法在turbo译码器中的应用。文章对基于近似算法的W CDM A turbo译码器在AW GN信道和平坦慢衰落Rayleigh信道上的纠错性能进行了仿真。仿真结果表明,二阶近似Log-M AP turbo译码器与M A P turbo译码器性能等价,优...该文研究近似Log-M AP算法在turbo译码器中的应用。文章对基于近似算法的W CDM A turbo译码器在AW GN信道和平坦慢衰落Rayleigh信道上的纠错性能进行了仿真。仿真结果表明,二阶近似Log-M AP turbo译码器与M A P turbo译码器性能等价,优于SO VA turbo译码器0.7-0.9dB。展开更多
基金supported by the Open Fund of Key Laboratory of Geo-detection (China University of Geosciences,Beijing),Ministry of Education (No. GDL0805)
文摘In this article, numerical modeling of borehole radar for well logging in time domain is developed using pseudo-spectral time domain algorithm in axisymmetric cylindrical coordinate for proximate true formation model. The conductivity and relative permittivity logging curves are obtained from the data of borehole radar for well logging. Since the relative permittivity logging curve is not affected by salinity of formation water, borehole radar for well logging has obvious advantages as compared with conventional electrical logging. The borehole radar for well logging is a one-transmitter and two-receiver logging tool. The conductivity and relative permittivity logging curves are obtained successfully by measuring the amplitude radio and the time difference of pulse waveform from two receivers. The calculated conductivity and relative permittivity logging curves are close to the true value of surrounding formation, which tests the usability and reliability of borehole radar for well logging. The numerical modeling of borehole radar for well logging laid the important foundation for researching its logging tool.
文摘数码管图像的目标和背景分离不明显,直方图分布较复杂。针对该问题,提出基于拉普拉斯高斯(Laplacian of Gaussian,LoG)算子边缘检测的全局二值化方法对其进行处理,该方法通过提取图像边缘部份的像素灰度获得图像二值化的阈值。处理结果表明,与传统的几种方法相比,该方法能够快速选取良好的二值化阈值,较好地区分目标和背景,在相当大模板宽度内图像二值化的结果都令人满意。
文摘该文研究近似Log-M AP算法在turbo译码器中的应用。文章对基于近似算法的W CDM A turbo译码器在AW GN信道和平坦慢衰落Rayleigh信道上的纠错性能进行了仿真。仿真结果表明,二阶近似Log-M AP turbo译码器与M A P turbo译码器性能等价,优于SO VA turbo译码器0.7-0.9dB。
