27,627 research outputs found
Monogenic-LBP: A new approach for rotation invariant texture classification
2010 17th IEEE International Conference on Image Processing, ICIP 2010, Hong Kong, 26-29 September 2010Analysis of two-dimensional textures has many potential applications in computer vision. In this paper, we investigate the problem of rotation invariant texture classification, and propose a novel texture feature extractor, namely Monogenic-LBP (M-LBP). M-LBP integrates the traditional Local Binary Pattern (LBP) operator with the other two rotation invariant measures: the local phase and the local surface type computed by the 1st-order and 2 nd-order Riesz transforms, respectively. The classification is based on the image's histogram of M-LBP responses. Extensive experiments conducted on the CUReT database demonstrate the overall superiority of M-LBP over the other state-of-the-art methods evaluated.Department of Computin
Rotation invariant texture classification using adaptive LBP with directional statistical features
2010 17th IEEE International Conference on Image Processing, ICIP 2010, Hong Kong, 26-29 September 2010Local Binary Pattern (LBP) has been widely used in texture classification because of its simplicity and computational efficiency. Traditional LBP codes the sign of the local difference and uses the histogram of the binary code to model the given image. However, the directional statistical information is ignored in LBP. In this paper, some directional statistical features, specifically the mean and standard deviation of the local absolute difference are extracted and used to improve the LBP classification efficiency. In addition, the least square estimation is used to adaptively minimize the local difference for more stable directional statistical features, and we call this scheme the adaptive LBP (ALBP). By coupling the directional statistical features with ALBP, a new rotation invariant texture classification method is presented. Experiments on a large texture database show that the proposed texture feature extraction and classification scheme could significantly improve the classification accuracy of LBP.Department of ComputingRefereed conference pape
Aromatic hydrocarbons as ozone precursors before and after outbreak of the 2008 financial crisis in the Pearl River Delta region, south China
In the second half of 2008 China's highly industrialized Pearl River Delta (PRD) region was hard-hit by the financial crisis (FC). This study reports volatile organic compounds measured in the PRD during November-December in both 2007 before the FC and 2008 after the FC. While total mixing ratios of non-methane hydrocarbons (NMHCs) on average were only about 7% lower from 40.2 ppbv in 2007 to 37.5 ppbv in 2008, their ozone formation potentials (OFPs) dropped about 30%, resulting from about 55% plummet of aromatic hydrocarbons (AHs) against a greater than 20% increase of total alkanes/alkenes. The elevated alkanes and alkenes in 2008 could be explained by greater emissions from vehicle exhausts and LPG combustion due to rapid increase of vehicle numbers and LPG consumption; the drop of AHs could be explained by reduced emissions from industries using AH-containing solvents due to the influence of the FC, as indicated by much lower ratios of toluene to benzene and of xylenes/ trichloroethylene/tetrachloroethylene to carbon monoxide (CO) in 2008. Source apportionment by positive matrix factorization (PMF) also revealed much less contribution of industry solvents to total anthropogenic NMHCs and particularly to toluene and xylenes in 2008 than in 2007. Based on PMF reconstructed source contributions, calculated OFPs by industrial emissions were responsible for 40.8% in 2007 in contrast to 18.4% in 2008. Further investigation into local industry output statistics suggested that the plummet of AHs in 2008 should be attributed to small enterprises, which contributed largely to ambient AHs due to their huge numbers and non-existent emission treatment, but were much more influenced by the FC. © 2012. American Geophysical Union. All Rights Reserved
Effect of modifier and superfine steel slag powder on properties of magnesium oxysulfate (MOS) cement
With the increasing of iron and steel production, the rational utilization of waste steel slag is very important. At present, it is common to use steel slag as admixture of Portland cement and concrete. In order to further investigate the effect of modifier and superfine steel slag powder on properties of magnesium oxysulfate (MOS) cement, the examinations of compressive strength, hydration products, and pore structure of various MOS cement mixtures are discussed in detail. The results show that malic acid helps the formation of 5Mg(OH)2·MgSO4·7H2O (517 phase) and gives MOS cement a finer pore structure. Addition of superfine steel slag powder can decrease the porosity and fine the pore size in the paste
High Dimensional Apollonian Networks
We propose a simple algorithm which produces high dimensional Apollonian
networks with both small-world and scale-free characteristics. We derive
analytical expressions for the degree distribution, the clustering coefficient
and the diameter of the networks, which are determined by their dimension
Anomalous thermoelectric effects of ZrTe in and beyond the quantum limit
Thermoelectric effects are more sensitive and promising probes to topological
properties of emergent materials, but much less addressed compared to other
physical properties. Zirconium pentatelluride (ZrTe) has inspired active
investigations recently because of its multiple topological nature. We study
the thermoelectric effects of ZrTe in a magnetic field and find several
anomalous behaviors. The Nernst response has a steplike profile near zero field
when the charge carriers are electrons only, suggesting the anomalous Nernst
effect arising from a nontrivial profile of Berry curvature. Both the
thermopower and Nernst signal exhibit exotic peaks in the strong-field quantum
limit. At higher magnetic fields, the Nernst signal has a sign reversal at a
critical field where the thermopower approaches to zero. We propose that these
anomalous behaviors can be attributed to the Landau index inversion, which is
resulted from the competition of the dependence of the Dirac-type
Landau bands and linear- dependence of the Zeeman energy ( is the
magnetic field). Our understanding to the anomalous thermoelectric properties
in ZrTe opens a new avenue for exploring Dirac physics in topological
materials.Comment: 6 pages, 4 figure
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Surface/Interface Carrier-Transport Modulation for Constructing Photon-Alternative Ultraviolet Detectors Based on Self-Bending-Assembled ZnO Nanowires.
Surface/interface charge-carrier generation, diffusion, and recombination/transport modulation are especially important in the construction of photodetectors with high efficiency in the field of nanoscience. In the paper, a kind of ultraviolet (UV) detector is designed based on ZnO nanostructures considering photon-trapping, surface plasmonic resonance (SPR), piezophototronic effects, interface carrier-trapping/transport control, and collection. Through carefully optimized surface/interface carrier-transport modulation, a designed device with detectivity as high as 1.69 × 1016/1.71 × 1016 cm·Hz1/2/W irradiating with 380 nm photons under ultralow bias of 0.2 V is realized by alternating nanoparticle/nanowire active layers, respectively, and the designed UV photodetectors show fast and slow recovery processes of 0.27 and 4.52 ms, respectively, which well-satisfy practical needs. Further, it is observed that UV photodetection could be performed within an alternative response by varying correlated key parameters, through efficient surface/interface carrier-transport modulation, spectrally resolved photoresponse of the detector revealing controlled detection in the UV region based on the ZnO nanomaterial, photodetection allowed or limited by varying the active layers, irradiation distance from one of the electrodes, standing states, or electric field. The detailed carrier generation, diffusion, and recombination/transport processes are well illustrated to explain charge-carrier dynamics contributing to the photoresponse behavior
Unprecedented Piezoresistance Coefficient in Strained Silicon Carbide
Unprecedented Piezoresistance Coefficient in Strained Silicon Carbid
Unprecedented enhancement of wear resistance for epoxy-resin graphene composites
Epoxy resins (ERs) have extraordinary mechanical, electrical and chemical properties, and are widely used in the aerospace, electronics and marine industries. Nonetheless, solidified ERs have intrinsic brittleness and low wear resistance. Until now, the promotion of the wear resistance of ER is limited to 30 times, through blending from one to four reinforcing materials. Therefore, it has been a challenge to enhance the wear resistance of ER to over 30 times. Additionally, mechanisms to improve the tribological properties of polymer composites are elusive. In this study, novel ER/graphene composites (ECs) were developed, and the wear resistance of EC with 5 wt% graphene (EC5) was shown to be 628 times that of pure ER at 10 N. To the best of our knowledge, the unprecedented enhancement of wear resistance for ER is the highest reported. The enhancement mechanisms of graphene reinforcement to ER were determined by molecular dynamics simulations. When the content of graphene reaches 5 wt%, exfoliated graphene flakes adhere the most on the surface of a stainless-steel ball during sliding tests, reducing the wear most effectively. However, when the content of graphene is over 5 wt%, graphene flakes accumulate inside the composites, and less exfoliated graphene flakes adhere to the surface of the ball during sliding, increasing the wear. The developed binary ECs are light-weight and cost-effective and have minimal impact on the environment. This composite has many potential applications for high-performance components used in the aerospace, electronics and marine industries
Total Reaction Cross Section in an Isospin-Dependent Quantum Molecular Dynamics (IDQMD) Model
The isospin-dependent quantum molecular dynamics (IDQMD) model is used to
study the total reaction cross section . The energy-dependent Pauli
volumes of neutrons and protons have been discussed and introduced into the
IDQMD calculation to replace the widely used energy-independent Pauli volumes.
The modified IDQMD calculation can reproduce the experimental well
for both stable and exotic nuclei induced reactions. Comparisons of the
calculated induced by with different initial density
distributions have been performed. It is shown that the calculation by using
the experimentally deduced density distribution with a long tail can fit the
experimental excitation function better than that by using the
Skyrme-Hartree-Fock calculated density without long tails. It is also found
that at high energy is sensitive to the long tail of density
distribution.Comment: 4 page, 4 fig
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