Discontinuities constitute an integral part of rock mass and inherently affect its anisotropic deformation behavior.This work focuses on the equivalent elastic deformation of rock mass with multiple persistent joint s...Discontinuities constitute an integral part of rock mass and inherently affect its anisotropic deformation behavior.This work focuses on the equivalent elastic deformation of rock mass with multiple persistent joint sets.A new method based on the space geometric and mechanical properties of the modified crack tensor is proposed,providing an analytical solution for the equivalent elastic compliance tensor of rock mass.A series of experiments validate the capability of the compliance tensor to accurately represent the deformation of rock mass with multiple persistent joint sets,based on conditions set by the basic hypothesis.The spatially varying rules of the equivalent elastic parameters of rock mass with a single joint set are analyzed to reveal the universal law of the stratified rock mass.展开更多
With the development of gravity gradient full tensor measurement technique,three-dimensional( 3D) inversion based on gravity gradient tensor can provide more accurate information. But the forward calculation of 3D ful...With the development of gravity gradient full tensor measurement technique,three-dimensional( 3D) inversion based on gravity gradient tensor can provide more accurate information. But the forward calculation of 3D full tensor sensitivity matrix is very time-consuming,which restricts its development and application.According to the symmetry of the kernel function,the authors reconstruct the underground source of geological body to avoid repeat computation of the same value,and work out the corresponding relationship between the response of geological body to the observation point and the response of reconstructed geological body to the observation point. According to the relationship,rapid calculation of full tensor gravity sensitivity matrix can be achieved. The model calculation shows that this method can increase the speed of 30-45 times compared with the traditional calculation method. The sensitivity matrix is applied to the multi-component inversion of gravity gradient. The application of this method on the measured data provides the basis for the promotion of the method.展开更多
针对彩色图像水印算法在滤波攻击下鲁棒性较差的问题,提出一种基于张量分解和联合熵的双彩色鲁棒水印算法.首先,将彩色载体图像整体进行张量分解得到其张量特征图并分块;然后,利用联合熵提取遮蔽性较好的特征图子块;最后,将水印信息嵌...针对彩色图像水印算法在滤波攻击下鲁棒性较差的问题,提出一种基于张量分解和联合熵的双彩色鲁棒水印算法.首先,将彩色载体图像整体进行张量分解得到其张量特征图并分块;然后,利用联合熵提取遮蔽性较好的特征图子块;最后,将水印信息嵌入到选定块经过奇异值分解(singular value decomposition,SVD)后的U矩阵中.实验结果表明,Lena图像峰值信噪比达39 dB以上,该算法不仅能有效抵抗图像的滤波攻击,NC值最高达1.0000,而且对其他常规图像攻击以及几何攻击也有较强的鲁棒性.展开更多
基金Projects(41172284,51379202) supported by the National Natural Science Foundation of ChinaProject(2013CB036405) supported by the National Basic Research Program of ChinaProject(2013BAB02B01) supported by the National Key Technologies R&D Program of China
文摘Discontinuities constitute an integral part of rock mass and inherently affect its anisotropic deformation behavior.This work focuses on the equivalent elastic deformation of rock mass with multiple persistent joint sets.A new method based on the space geometric and mechanical properties of the modified crack tensor is proposed,providing an analytical solution for the equivalent elastic compliance tensor of rock mass.A series of experiments validate the capability of the compliance tensor to accurately represent the deformation of rock mass with multiple persistent joint sets,based on conditions set by the basic hypothesis.The spatially varying rules of the equivalent elastic parameters of rock mass with a single joint set are analyzed to reveal the universal law of the stratified rock mass.
基金Support by Project of Geophysical Comprehensive Survey and Information Extraction of Deep Mineral Resources(2016YFC0600505)
文摘With the development of gravity gradient full tensor measurement technique,three-dimensional( 3D) inversion based on gravity gradient tensor can provide more accurate information. But the forward calculation of 3D full tensor sensitivity matrix is very time-consuming,which restricts its development and application.According to the symmetry of the kernel function,the authors reconstruct the underground source of geological body to avoid repeat computation of the same value,and work out the corresponding relationship between the response of geological body to the observation point and the response of reconstructed geological body to the observation point. According to the relationship,rapid calculation of full tensor gravity sensitivity matrix can be achieved. The model calculation shows that this method can increase the speed of 30-45 times compared with the traditional calculation method. The sensitivity matrix is applied to the multi-component inversion of gravity gradient. The application of this method on the measured data provides the basis for the promotion of the method.
文摘针对彩色图像水印算法在滤波攻击下鲁棒性较差的问题,提出一种基于张量分解和联合熵的双彩色鲁棒水印算法.首先,将彩色载体图像整体进行张量分解得到其张量特征图并分块;然后,利用联合熵提取遮蔽性较好的特征图子块;最后,将水印信息嵌入到选定块经过奇异值分解(singular value decomposition,SVD)后的U矩阵中.实验结果表明,Lena图像峰值信噪比达39 dB以上,该算法不仅能有效抵抗图像的滤波攻击,NC值最高达1.0000,而且对其他常规图像攻击以及几何攻击也有较强的鲁棒性.
