9,599 research outputs found

    Exploring Locally Rigid Discriminative Patches for Learning Relative Attributes

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    Relative attributes help in comparing two images based on their visual properties. These are of great interest as they have been shown to be useful in several vision related problems such as recognition, retrieval, and understanding image collections in general. In the recent past, quite a few techniques have been proposed for the relative attribute learning task that give reasonable performance. However, these have focused either on the algorithmic aspect or the representational aspect. In this work, we revisit these ap-proaches and integrate their broader ideas to develop simple baselines. These not only take care of the algorithmic aspects, but also take a step towards analyzing a simple yet domain independent patch-based representation for this task. This representation can capture local shape in an image, as well as spatially rigid correspondences across regions in an image pair. The baselines are extensively evaluated on three challenging relative attribute datasets (OSR, LFW-10 and UT-Zap50K). Experiments demonstrate that they achieve promising results on the OSR and LFW-10 datasets, and perform better than the current state-of-the-art on the UT-Zap50K dataset. Moreover, they also provide some interesting insights about the problem, that could be helpful in developing the future techniques in this domain.

    Computation of Kolmogorov's Constant in Magnetohydrodynamic Turbulence

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    In this paper we calculate Kolmogorov's constant for magnetohydrodynamic turbulence to one loop order in perturbation theory using the direct interaction approximation technique of Kraichnan. We have computed the constants for various Eu(k)/Eb(k)E^u(k)/E^b(k), i.e., fluid to magnetic energy ratios when the normalized cross helicity is zero. We find that KK increases from 1.47 to 4.12 as we go from fully fluid case (Eb=0)(E^b=0) to a situation when Eu/Eb=0.5% E^u/E^b=0.5, then it decreases to 3.55 in a fully magnetic limit (Eu=0)(E^u=0). When Eu/Eb=1E^u/E^b=1, we find that K=3.43K=3.43.Comment: Latex, 10 pages, no figures, To appear in Euro. Phys. Lett., 199

    Energy fluxes in helical magnetohydrodynamics and dynamo action

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    Renormalized viscosity, renormalized resistivity, and various energy fluxes are calculated for helical magnetohydrodynamics using perturbative field theory. The calculation is to first-order in perturbation. Kinetic and magnetic helicities do not affect the renormalized parameters, but they induce an inverse cascade of magnetic energy. The sources for the the large-scale magnetic field have been shown to be (1) energy flux from large-scale velocity field to large-scale magnetic field arising due to nonhelical interactions, and (2) inverse energy flux of magnetic energy caused by helical interactions. Based on our flux results, a premitive model for galactic dynamo has been constructed. Our calculations yields dynamo time-scale for a typical galaxy to be of the order of 10810^8 years. Our field-theoretic calculations also reveal that the flux of magnetic helicity is backward, consistent with the earlier observations based on absolute equilibrium theory.Comment: REVTEX4; A factor of 2 corrected in helicit

    Large-Eddy Simulations of Fluid and Magnetohydrodynamic Turbulence Using Renormalized Parameters

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    In this paper a procedure for large-eddy simulation (LES) has been devised for fluid and magnetohydrodynamic turbulence in Fourier space using the renormalized parameters. The parameters calculated using field theory have been taken from recent papers by Verma [Phys. Rev. E, 2001; Phys. Plasmas, 2001]. We have carried out LES on 64364^3 grid. These results match quite well with direct numerical simulations of 1283128^3. We show that proper choice of parameter is necessary in LES.Comment: 12 pages, 4 figures: Proper figures inserte

    Local shell-to-shell energy transfer via nonlocal Interactions in fluid turbulence

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    In this paper we analytically compute the strength of nonlinear interactions in a triad, and the energy exchanges between wavenumber shells in incompressible fluid turbulence. The computation has been done using first-order perturbative field theory. In three dimension, magnitude of triad interactions is large for nonlocal triads, and small for local triads. However, the shell-to-shell energy transfer rate is found to be local and forward. This result is due to the fact that the nonlocal triads occupy much less Fourier space volume than the local ones. The analytical results on three-dimensional shell-to-shell energy transfer match with their numerical counterparts. In two-dimensional turbulence, the energy transfer rates to the near-by shells are forward, but to the distant shells are backward; the cumulative effect is an inverse cascade of energy.Comment: 10 pages, Revtex

    Resistivity dependent dielectric and magnetic properties of Pb(Fe0.012Ti0.988)O3 nanoparticles

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    High resistivity in nanostructured Pb(Fe0.012Ti0.988)O3 system prepared by using polyvinyl alcohol (PVA) in chemical route is observed. The PVA acts as a surfactant to limit the particle size. The Fe substitution for Ti controls the chemical stoichiometry and reduces the lattice distortion, i.e., c/a ratio, and hence the transition temperature reduces with Fe content. The phase structure, morphology, particle size, dc resistivity, and dielectric and magnetic properties of Pb(Fe0.012Ti0.988)O3 nanoparticles have been characterized by x-ray diffraction, transmission/scanning electron microscopy, source meter, LCR meter, and vibrating sample magnetometer. The results indicate that the nanosize particles have high resistivity, which improves the dielectric constant at high-frequency region and increases magnetization of the specimens. The observed variable-range-hopping conduction mechanism indicates that Fe doping leads to the occurrence of local defect states in the PbTiO3 lattice. The dispersionless dielectric properties with low loss are observed up to 15 MHz. The dielectric properties are improved than those obtained by the conventional process. The initial permeability values do not exhibit much variation up to ferromagnetic transition temperature after which it falls sharply. The large value of saturation magnetization is observed at room temperature

    Branching ratios of Bc Meson Decaying to Pseudoscalar and Axial-Vector Mesons

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    We study Cabibbo-Kobayashi-Maskawa (CKM) favored weak decays of Bc mesons in the Isgur-Scora-Grinstein-Wise (ISGW) quark model. We present a detailed analysis of the Bc meson decaying to a pseudoscalar meson (P) and an axial-vector meson (A). We also give the form factors involving transition in the ISGW II framework and consequently, predict the branching ratios of decays.Comment: 19 pages,7 table

    Influence of NPK levels on growth and yield of Stevia rebaudiana Bertoni under hills of Uttarakhand

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    66-72A field experiment was carried out at CSIR-Central Institute of Medicinal and Aromatic Plant Research Centre Purara, Bageshwar, Uttarakhand, India during 2014 and 2015 in sandy loam soil on Influence of NPK levels on plant growth and yield of Stevia rebaudiana Bertoni under lower hills of Kumaon Uttarakhand were tested in a randomized block design with factorial concept in three replications. Four harvestings were taken in a year. Stevia were treated with three doses of nitrogen (100,200,300 N kg/ha), three doses of phosphorus (60,120,180 P2O5 kg/ha) and two levels of potassium (80,160 K2O kg/ha). Pooled results indicated that significantly higher dry leaf yield was obtained with nitrogen @ 300 Kg/ha (45.68 t/ha) and it was on par with 200 kg/ha (43.76 t/ha). Phosphorus @ 180/ha recorded significantly highest dry leaf yield (40.68 t/ha) and it was on par with 120 kg/ha (43.40 t/ha). Potassium @ 160 kg/ha recorded dry leaf yield of 43.12 t/ha and it was comparable with potassium @80 kg/ha (41.84 t/ha). The growth parameters viz., plant height (cm), number of branches per plant and number of leaves per plant were significantly higher with nitrogen, phosphorus and potassium @ 300 kg/ha, 180 kg/ha and 160 kg/ha, respectively which were on par with 200 kg/ha, 120 kg/ha and 80 kg/ha respectively. In pooled data nitrogen N3 i.e., 300 kg/ha recorded the highest B:C (4.60) which was on par with nitrogen @ N2 i.e., 200 kg/ha (4.34), but significantly higher than N1 i.e., 100 kg/ha (3.38). Phosphorous P3 i.e., 180 kg/ha resulted in higher B:C (4.61) which was on par with P2 i.e., 120 kg/ha (4.50). Potassium level influenced the B:C non-significantly. Significantly lowest B:C was recorded with absolute control in pooled data (2.19). Nutrient level of 300:180:160 kg/ha NPK applied in equal splits to four harvestings in a year has been considered as an economically optimum level of nutrients for stevia
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