The U1 matrix and extreme U1 matrix were successfully used to study quadratic doubly stochastic operators by R. Ganikhodzhaev and F. Shahidi [Linear Algebra Appl., 2010, 432： 24-35], where a necessary condition for a...
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The U1 matrix and extreme U1 matrix were successfully used to study quadratic doubly stochastic operators by R. Ganikhodzhaev and F. Shahidi [Linear Algebra Appl., 2010, 432： 24-35], where a necessary condition for a U1 matrix to be extreme was given. S. Yang and C. Xu [Linear Algebra Appl., 2013, 438： 3905-3912] gave a necessary and sufficient condition for a symmetric nonnegative matrix to be an extreme U1 matrix and investigated the structure of extreme U1 matrices. In this paper, we count the number of the permutation equivalence classes of the n × n extreme U1 matrices and characterize the structure of the quadratic stochastic operators and the quadratic doubly stochastic operators.
Spectral efficiency and transmission reliability are among the main design considerations of modern wireless communication systems. In order to solve the problems of high decoding complexity, low spectrum utilization ...
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In this paper, a novel wideband dual-band magneto-electric dipole antenna with modified feed structure is proposed. Double-layer patches are utilized to design a pair of folding metal. The double-layer patches dipole ...
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In this paper, a novel wideband dual-band magneto-electric dipole antenna with modified feed structure is proposed. Double-layer patches are utilized to design a pair of folding metal. The double-layer patches dipole can generate two resonant frequencies, which are employed to form a dual-band magneto-electric dipole antenna. A stair-shaped feeding strip with a hexagonal structure is designed to modify the impedance matching. It is found from simulated results that two operation bands with bandwidths of 60% from 1.61 to 2.99 GHz and 31.9% from 4.99 to 6.89 GHz under the return loss level of 10 dB were achieved. The gain of the antenna ranged from 7.56 to 10.56 dBi. Furthermore, low cross-polarization level and low back-radiation are also obtained with the proposed antenna.
Considering the photonic crystal structure is critical to the future development of communication, the enthusiasm for the research of photonic crystal is always high. In this paper, the nonlinear finite-difference tim...
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ISBN:
(纸本)9781450353489
Considering the photonic crystal structure is critical to the future development of communication, the enthusiasm for the research of photonic crystal is always high. In this paper, the nonlinear finite-difference time-domain method is used to analyze the transmission characteristics of one-dimensional photonic crystal structure. As the center frequency of the optical pulse approaches is closed to the photonic band gap, the group velocity dispersion of the light pulse increases. In addition, soliton waves can be generated in the structure with the introduction of Kerr nonlinear. And soliton waves can make outstanding contributions to the accurate transmission of information.
For the defect in describing affine and blur invariable of scale-invariant feature transform (SIFT) at large viewpoint variation, a new object recognition method is proposed in this paper, which used maximally stable ...
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Research in texture recognition often concentrates on recognizing textures with intraclass variations such as illumination, rotation, viewpoint and small scale changes. In contrast, in real-world applications a change...
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At present, in related image processing field, the fuzzy set theory has also gained more successful applications to some extent. The image processing based on the fuzzy theory is an important research area. The inform...
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At present, in related image processing field, the fuzzy set theory has also gained more successful applications to some extent. The image processing based on the fuzzy theory is an important research area. The information loss brought by 3D object projection in 2D image plane makes the image have the ambiguity exist in essence, thus there exists ambiguity when defining image characteristics such as the border, area and texture, therefore, because of the complexity of the image itself, uncertainty and inaccuracy or ambiguity may occur in the different stages of the processing. The algorithm in this paper improves the degree of membership function to make it suitable for the image fuzzy enhancement. The membership function curve is S-shaped, and at the inflection point, the function value on the left side drops rapidly while the function value on the right side rapidly rises. There is certain symmetry about the inflection point, and the function inflection point position can be decided by changing function parameters, and better enhancement effect can be gained by a small amount of iteration. By the experimental simulation, it is verified that the enhanced color image by adopting the method in this paper is bright in color on the visual effect with moderate increasing proportion of brightness and contrast, and best color maintaining performance and minimum chromaticity change, and also the image information entropy is improved when compared with the original image data.
This paper presents a novel image fusion method based on nonsubsampled shearlet transform (NSST) and block-based random image sampling for infrared and visible images. In the method, the NSST is firstly performed on e...
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This paper presents a novel image fusion method based on nonsubsampled shearlet transform (NSST) and block-based random image sampling for infrared and visible images. In the method, the NSST is firstly performed on each of the source images to obtain their low frequency and high frequency subbands coefficients. Then the low frequency coefficients are fused by combing the block-based random image sampling and the sliding widow technique, while the high frequency coefficients are fused using classical absolute value maximum choosing rule. The fused image is reconstructed though performing the inverse NSST. The experiments are carried out on five pairs of infrared and visible images using five traditional fusion methods to verify the effectiveness and efficiency of the proposed method and by comparing the fused results visually and objectively it is demonstrated that the proposed fusion method is competitive or even superior to the other wellknown methods.
Image enhancement, as a means of digital image processing, often is fuzzy. Based on defects of excessive enhancement and insufficient detail enhancement existing in the traditional image enhancement method, this paper...
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Image enhancement, as a means of digital image processing, often is fuzzy. Based on defects of excessive enhancement and insufficient detail enhancement existing in the traditional image enhancement method, this paper proposes a self-adaptive image enhancement method based on variable fuzzy sets, and such method can, according to the image's gray-scale properties, introduce the relative gray-scale level of the pixel as the fuzzy feature, and adopt the improved membership function to conduct the fuzzy enhancement, thus avoiding the loss of a great deal of gray-scale information after the enhancement. The paper also introduces the selection of optimal parameters, ensures the quality of the image enhanced and improves the feasibility and efficiency of this algorithm. This algorithm, on the basis of keeping the image's original brightness, enhances the image details at the same time. Experimental results show that such algorithm can obtain good visual effect and more obvious detail information.
The dual of the Kasami code of length q2 − 1, with q a power of 2, is constructed by concatenating a cyclic MDS code of length q + 1 over Fq with a Simplex code of length q − 1. This yields a new derivation of the wei...
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