382 research outputs found

    σ\sigma-models on the quantum group manifolds SLq(2,R)SL_{q}(2,R), SLq(2,R)/Uh(1)SL_{q}(2,R)/U_{h}(1), Cq(20)C_{q}(2|0) and infinitesimal trasformations

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    The differential and variational calculus on the SLq(2,R)SL_{q}(2,R) group is constructed. The spontaneous breaking symmetry in the WZNW model with SLq(2,R)SL_{q}(2,R) quantum group symmetry and in the σ\sigma-models with SLq(2,R)/Uh(1){SL_{q}(2,R)/U_{h}(1)} ,Cq(20)C_{q}(2|0) quantum group symmetry is considered. The Lagrangian formalism over the quantum group manifolds is discussed. The classical solution of Cq(20)C_{q}(2|0) {σ\sigma}-model is obtained.Comment: LaTex, 7 page

    Toward Generalized Psychovisual Preprocessing For Video Encoding

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    Deep perceptual preprocessing has recently emerged as a new way to enable further bitrate savings across several generations of video encoders without breaking standards or requiring any changes in client devices. In this article, we lay the foundation for a generalized psychovisual preprocessing framework for video encoding and describe one of its promising instantiations that is practically deployable for video-on-demand, live, gaming, and user-generated content (UGC). Results using state-of-the-art advanced video coding (AVC), high efficiency video coding (HEVC), and versatile video coding (VVC) encoders show that average bitrate [Bjontegaard delta-rate (BD-rate)] gains of 11%-17% are obtained over three state-of-the-art reference-based quality metrics [Netflix video multi-method assessment fusion (VMAF), structural similarity index (SSIM), and Apple advanced video quality tool (AVQT)], as well as the recently proposed nonreference International Telecommunication Union-Telecommunication?(ITU-T) P.1204 metric. The proposed framework on CPU is shown to be twice faster than × 264 medium-preset encoding. On GPU hardware, our approach achieves 714 frames/sec for 1080p video (below 2 ms/frame), thereby enabling its use in very-low-latency live video or game streaming applications

    Escaping the complexity-bitrate-quality barriers of video encoders via deep perceptual optimization

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    We extend the concept of learnable video precoding (rate-aware neural-network processing prior to encoding) to deep perceptual optimization (DPO). Our framework comprises a pixel-to-pixel convolutional neural network that is trained based on the virtualization of core encoding blocks (block transform, quantization, block-based prediction) and multiple loss functions representing rate, distortion and visual quality of the virtual encoder. We evaluate our proposal with AVC/H.264 and AV1 under per-clip rate-quality optimization. The results show that DPO offers, on average, 14.2% bitrate reduction over AVC/H.264 and 12.5% bitrate reduction over AV1. Our framework is shown to improve both distortion- and perception-oriented metrics in a consistent manner, exhibiting only 3% outliers, which correspond to content with peculiar characteristics. Thus, DPO is shown to offer complexity-bitrate-quality tradeoffs that go beyond what conventional video encoders can offe

    On the R-Matrix Formulation of Deformed Algebras and Generalized Jordan-Wigner Transformations

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    The deformed algebra A(R)\cal{A(R)}, depending upon a Yang-Baxter R- matrix, is considered. The conditions under which the algebra is associative are discussed for a general number of oscillators. Four types of solutions satisfying these conditions are constructed and two of them can be represented by generalized Jordan-Wigner transformations.Our analysis is in some sense an extension of the boson realization of fermions from single-mode to multimode oscillators.Comment: 10+ii pages,preprint RBI-TH-10/93,Latex,(to appear in Europhys.Lett.

    Correlation effects during liquid infiltration into hydrophobic nanoporous mediums

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    Correlation effects arising during liquid infiltration into hydrophobic porous medium are considered. On the basis of these effects a mechanism of energy absorption at filling porous medium by nonwetting liquid is suggested. In accordance with this mechanism, the absorption of mechanical energy is a result expenditure of energy for the formation of menisci in the pores on the shell of the infinite cluster and expenditure of energy for the formation of liquid-porous medium interface in the pores belonging to the infinite cluster of filled pores. It was found that in dependences on the porosity and, consequently, in dependences on the number of filled pores neighbors, the thermal effect of filling can be either positive or negative and the cycle of infiltration-defiltration can be closed with full outflow of liquid. It can occur under certain relation between percolation properties of porous medium and the energy characteristics of the liquid-porous medium interface and the liquid-gas interface. It is shown that a consecutive account of these correlation effects and percolation properties of the pores space during infiltration allow to describe all experimental data under discussion

    REARRANGEMENT OF FURYL-TETHERED OXIMES: SYNTHESIS OF FUNCTIONALIZED PYRROLES

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    Polyarylated pyrroles have been extensively utilized as building-blocks in material science. High demand for functionalyzed pyrrole substrates motivated us to develop a general synthetic protocol toward such valuable compounds based on furan dearomatization approach.This work was supported by the Russian Foundation for Basic Research, project # 20-33-70079

    REARRANGEMENT OF FURYL-TETHERED OXIMES: SYNTHESIS OF FUNCTIONALIZED PYRROLES

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    This work was supported by the Russian Foundation for Basic Research, project # 20-33-70079

    Coordinate Representation of the Two-Spinon wavefunction and Spinon Interaction

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    By deriving and studying the coordinate representation for the two-spinon wavefunction, we show that spinon excitations in the Haldane-Shastry model interact. The interaction is given by a short-range attraction and causes a resonant enhancement in the two-spinon wavefunction at short separations between the spinons. We express the spin susceptibility for a finite lattice in terms of the resonant enhancement, given by the two-spinon wavefunction at zero separation. In the thermodynamic limit, the spinon attraction turns into the square-root divergence in the dynamical spin susceptibility.Comment: 19 pages, 5 .eps figure

    Structural and magnetic studies of FE100–xCox nanotubes obtaine by template method

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    Hollow nanostructures based on the Fe100–xCox alloy were synthesized in the pores of polymer template matrices based on PET using the electrochemical deposition method. Morphology, elemental composition, and structural features were characterized by scanning electron microscopy, energy dispersive analysis, and X-ray diffractometry. The study of the internal magnetic texture was carried out using Mossbauer spectroscopy. The dependence of the change in structural and magnetic properties from the atomic content of components in nanotube structure is revealed. It is established that the synthesized nanostructures are hollow Fe100–xCox nanotubes with a body-centered cubic crystal structure. The decrease in the unit cell parameter with increasing cobalt concentration is due to the difference in the radii of Fe (1.227 Å) and Co (1.191 Å) atoms. It is established that a random distribution of magnetic moments directions of Fe atoms is observed for Fe100Co0 nanotubes. And magnetic texture along the nanotube axis is observed for Fe100–xCox nanotubes, with an increase in Co atoms concentration. The average angle between the direction of the magnetic moment of iron atoms and the nanotube axis decreases from v = 54:6° to v = 24:5°. © 2018, Electromagnetics Academy. All rights reserved

    СПЕКТР ЗУБОЧЕЛЮСТНЫХ АНОМАЛИЙ У ПАЦИЕНТОВ С ГОРИЗОНТАЛЬНЫМ ТИПОМ РОСТА ЛИЦА

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    The spectrum of malocclusions in orthodontic patients with a horizontal growth pattern was under study. It was found, that in most cases horizontal type of facial growth was combined with malocclusion class II, which was caused by mandibular mycrognathia. Patients with horizontal growth pattern had mandibular protraction much more often, than patients of the control group. It was found that horizontal grows pattern was frequently accompanied by decreased value of an intermandibularangle, anterior position of mandible and maxilla, prominent chin, increased size of a mandibular ramus and decreased mandibular angle value.Исследован спектр зубочелюстных аномалий у пациентов с горизонтальным типом роста, обратившихся за ортодонтической помощью. Выявлено, что чаще всего горизонтальный тип роста характеризовался дистальным соотношением зубных рядов, которое сопровождалось нижней микрогнатией. У пациентов с горизонтальным типом роста значительно чаще, чем у пациентов контрольной группы, встречалась нижняя прогнатия. Было определено, что наиболее характерными признаками горизонтального типа роста являются уменьшение межчелюстного угла, переднее положение верхней и нижней челюсти, переднее положение подбородка, увеличение длины ветви нижней челюсти, уменьшение угла развернутости нижней челюсти
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