We study iterative methods for solving a set of sparse non-negative tensor equations （multivariate polynomial systems） arising from data mining applications such as information retrieval by query search and communit...We study iterative methods for solving a set of sparse non-negative tensor equations （multivariate polynomial systems） arising from data mining applications such as information retrieval by query search and community discovery in multi-dimensional networks. By making use of sparse and non-negative tensor structure, we develop Jacobi and Gauss-Seidel methods for solving tensor equations. The multiplication of tensors with vectors are required at each iteration of these iterative methods, the cost per iteration depends on the number of non-zeros in the sparse tensors. We show linear convergence of the Jacobi and Gauss-Seidel methods under suitable conditions, and therefore, the set of sparse non-negative tensor equations can be solved very efficiently. Experimental results on information retrieval by query search and community discovery in multi-dimensional networks are presented to illustrate the application of tensor equations and the effectiveness of the proposed methods.展开更多
The classical Gerchberg-Saxton algorithm is introduced into the image recovery in fractional Fourier domain after adaptation. When this algorithm is applied directly, its performance is good for smoothed image, but ba...The classical Gerchberg-Saxton algorithm is introduced into the image recovery in fractional Fourier domain after adaptation. When this algorithm is applied directly, its performance is good for smoothed image, but bad for unsmoothed image. Based on the diversity of fractional Fourier transform on its orders, this paper suggests a novel iterative algorithm, which extracts the information of the original image from amplitudes of its fractional Fourier transform at two orders. This new algorithm consists of two independent Gerchberg-Saxton procedures and an averaging operation in each circle. Numerical simulations are carried out to show its validity for both smoothed and unsmoothed images with most pairs of orders in the interval [0, 1].展开更多
The properties of a series of phase measurement techniques,including interferometry,the Hartmann–Shack wavefront sensor,the knife-edge technique,and coherent diffraction imaging,are summarized and their performance i...The properties of a series of phase measurement techniques,including interferometry,the Hartmann–Shack wavefront sensor,the knife-edge technique,and coherent diffraction imaging,are summarized and their performance in high power laser applications is compared.The advantages,disadvantages,and application ranges of each technique are discussed.展开更多
Coherent diffraction imaging （CDI） and ptychography techniques bypass the difficulty of having high- quality optics in X-ray microscopy by using a numerical reconstruction of the image that is obtained by inverting ...Coherent diffraction imaging （CDI） and ptychography techniques bypass the difficulty of having high- quality optics in X-ray microscopy by using a numerical reconstruction of the image that is obtained by inverting the diffracted intensity recorded by a charge-coupled device array. However, the reconstruction of the image from the intensity data obtained from a weakly diffracting specimen is known to be difficult because of the obvious reduction in signal-to-noise ratio （SNR）. In this case, the specimen only slightly modifies the probe diffraction pattern~ resulting in difficulty in the identification of the detailed structure of the specimen from the reconstructed image because of the poor contrast and sharpness of the image. To address this situation, a modification in the image retrieval algorithms used in the iterative reconstruction of the image is suggested. This modification should double the presence of high spatial frequencies in the diffraction pattern to enhance the contrast and edge detection in existing imaging techniques.展开更多
Atmospheric water vapor profiles can be inferred from satellite infrared measurements. But at present only the total amount of atmospheric water vapor can be determined quite accurately, while the result of moisture r...Atmospheric water vapor profiles can be inferred from satellite infrared measurements. But at present only the total amount of atmospheric water vapor can be determined quite accurately, while the result of moisture retrieval has not been satisfied yet. In this paper are reported the simulations and reasonable results obtained.展开更多
轮廓点分布直方图CPDH(Contours Points Distribution Histogram)是一种形状描述子,但它对微小形变比较敏感且在大数据集下的检索效果不佳。提出基于协同传递机制的半监督学习框架Co-transduction与CPDH相结合的算法。通过给定CPDH的相...轮廓点分布直方图CPDH(Contours Points Distribution Histogram)是一种形状描述子,但它对微小形变比较敏感且在大数据集下的检索效果不佳。提出基于协同传递机制的半监督学习框架Co-transduction与CPDH相结合的算法。通过给定CPDH的相似度度量和另一种描述符的度量结果,对一幅查询图像,利用其中一种度量准则迭代检索出与查询图像最相似的目标形状将其标记。用另一种相似性度量重新检索并排序已标记的形状,反之亦然。该改进算法较原始CPDH在大数据集下(MPEG-7)的检索性能更优,检索精确率达到86%,比原算法提高约10%。展开更多
文摘We study iterative methods for solving a set of sparse non-negative tensor equations （multivariate polynomial systems） arising from data mining applications such as information retrieval by query search and community discovery in multi-dimensional networks. By making use of sparse and non-negative tensor structure, we develop Jacobi and Gauss-Seidel methods for solving tensor equations. The multiplication of tensors with vectors are required at each iteration of these iterative methods, the cost per iteration depends on the number of non-zeros in the sparse tensors. We show linear convergence of the Jacobi and Gauss-Seidel methods under suitable conditions, and therefore, the set of sparse non-negative tensor equations can be solved very efficiently. Experimental results on information retrieval by query search and community discovery in multi-dimensional networks are presented to illustrate the application of tensor equations and the effectiveness of the proposed methods.
文摘The classical Gerchberg-Saxton algorithm is introduced into the image recovery in fractional Fourier domain after adaptation. When this algorithm is applied directly, its performance is good for smoothed image, but bad for unsmoothed image. Based on the diversity of fractional Fourier transform on its orders, this paper suggests a novel iterative algorithm, which extracts the information of the original image from amplitudes of its fractional Fourier transform at two orders. This new algorithm consists of two independent Gerchberg-Saxton procedures and an averaging operation in each circle. Numerical simulations are carried out to show its validity for both smoothed and unsmoothed images with most pairs of orders in the interval [0, 1].
基金supported by the One Hundred Talents Project of the Chinese Academy of Sciences,China (Grant No.1204341-XR0)
文摘The properties of a series of phase measurement techniques,including interferometry,the Hartmann–Shack wavefront sensor,the knife-edge technique,and coherent diffraction imaging,are summarized and their performance in high power laser applications is compared.The advantages,disadvantages,and application ranges of each technique are discussed.
基金supported by the One Hundred Person Project of Chinese Academy of Sciences under Grant No.1104331-JR0
文摘Coherent diffraction imaging （CDI） and ptychography techniques bypass the difficulty of having high- quality optics in X-ray microscopy by using a numerical reconstruction of the image that is obtained by inverting the diffracted intensity recorded by a charge-coupled device array. However, the reconstruction of the image from the intensity data obtained from a weakly diffracting specimen is known to be difficult because of the obvious reduction in signal-to-noise ratio （SNR）. In this case, the specimen only slightly modifies the probe diffraction pattern~ resulting in difficulty in the identification of the detailed structure of the specimen from the reconstructed image because of the poor contrast and sharpness of the image. To address this situation, a modification in the image retrieval algorithms used in the iterative reconstruction of the image is suggested. This modification should double the presence of high spatial frequencies in the diffraction pattern to enhance the contrast and edge detection in existing imaging techniques.
文摘Atmospheric water vapor profiles can be inferred from satellite infrared measurements. But at present only the total amount of atmospheric water vapor can be determined quite accurately, while the result of moisture retrieval has not been satisfied yet. In this paper are reported the simulations and reasonable results obtained.
文摘轮廓点分布直方图CPDH(Contours Points Distribution Histogram)是一种形状描述子,但它对微小形变比较敏感且在大数据集下的检索效果不佳。提出基于协同传递机制的半监督学习框架Co-transduction与CPDH相结合的算法。通过给定CPDH的相似度度量和另一种描述符的度量结果,对一幅查询图像,利用其中一种度量准则迭代检索出与查询图像最相似的目标形状将其标记。用另一种相似性度量重新检索并排序已标记的形状,反之亦然。该改进算法较原始CPDH在大数据集下(MPEG-7)的检索性能更优,检索精确率达到86%,比原算法提高约10%。
