25,089 research outputs found

    A Convolutional Neural Network Approach for Half-Pel Interpolation in Video Coding

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    Motion compensation is a fundamental technology in video coding to remove the temporal redundancy between video frames. To further improve the coding efficiency, sub-pel motion compensation has been utilized, which requires interpolation of fractional samples. The video coding standards usually adopt fixed interpolation filters that are derived from the signal processing theory. However, as video signal is not stationary, the fixed interpolation filters may turn out less efficient. Inspired by the great success of convolutional neural network (CNN) in computer vision, we propose to design a CNN-based interpolation filter (CNNIF) for video coding. Different from previous studies, one difficulty for training CNNIF is the lack of ground-truth since the fractional samples are actually not available. Our solution for this problem is to derive the "ground-truth" of fractional samples by smoothing high-resolution images, which is verified to be effective by the conducted experiments. Compared to the fixed half-pel interpolation filter for luma in High Efficiency Video Coding (HEVC), our proposed CNNIF achieves up to 3.2% and on average 0.9% BD-rate reduction under low-delay P configuration.Comment: International Symposium on Circuits and Systems (ISCAS) 201

    Study on the Rheological Properties and Constitutive Model of Shenzhen Mucky Soft Soil

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    In order to obtain the basic parameters of numerical analysis about the time-space effect of the deformation occurring in Shenzhen deep soft-soil foundation pit, a series of triaxial consolidated-undrained shear rheology tests on the peripheral mucky soft soil of a deep foundation pit support were performed under different confining pressures. The relations between the axial strain of the soil and time, as well as between the pore-water pressure of the soil and time, were achieved, meanwhile on the basis of analyzing the rheological properties of the soil, the relevant rheological models were built. Analysis results were proved that the rheology of Shenzhen mucky soft soil was generally viscous, elastic, and plastic, and had a low yield stress between 90 and 150 kPa. The increase in pore-water pressure made the rheological time effect of the mucky soft soil more remarkable. Thus, the drainage performance in practical engineering should be improved to its maximum possibility extent to decrease the soft-soil rheological deformation. Lastly, a six-component extended Burgers model was employed to fit the test results and the parameters of the model were determined. Findings showed that the extended Burgers model could satisfactorily simulate the various rheological stages of the mucky soft soil. The constitutive model and the determination of its parameters can be served as a foundation for the time-space effect analysis on the deformation of deep soft-soil foundation pits

    The Pseudoscalar Meson and Heavy Vector Meson Scattering Lengths

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    We have systematically studied the S-wave pseudoscalar meson and heavy vector meson scattering lengths to the third order with the chiral perturbation theory, which will be helpful to reveal their strong interaction. For comparison, we have presented the numerical results of the scattering lengths (1) in the framework of the heavy meson chiral perturbation theory and (2) in the framework of the infrared regularization. The chiral expansion converges well in some channels.Comment: 10 pages, 1 figures, 4 tables. Corrected typos, Improved numerical results, and More dicussions. Accepted for publication by Phys.Rev.

    (E)-3-(2-Chloro-3,3,3-trifluoro­prop-1-en­yl)-2,2-dimethyl-N,N-diphenyl­cyclo­propane­carboxamide

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    The title compound, C21H19ClF3NO, was synthesized from 3-[(E)-2-chloro-3,3,3-trifluoro­prop-1-en­yl]-2,2-dimethyl­cyclo­propane­carboxylic acid and diphenyl­amine. The propenyl and carboxamide substituents lie on the same side of the cyclo­propane ring plane, with the two methyl substituents on either side of the plane. The phenyl rings of the carboxamide are inclined at an angle of 84.6 (3)° to one another. The F atoms are disordered over two positions; the site occupancy factors are ca 0.6 and 0.4
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