13,172 research outputs found
Finding Faces in Cluttered Scenes using Random Labeled Graph Matching
An algorithm for locating quasi-frontal views of human faces in cluttered scenes is presented. The algorithm works by coupling a set of local feature detectors with a statistical model of the mutual distances between facial features it is invariant with respect to translation, rotation (in the plane), and scale and can handle partial occlusions of the face. On a challenging database with complicated and varied backgrounds, the algorithm achieved a correct localization rate of 95% in images where the face appeared quasi-frontally
Novel Phases and Finite-Size Scaling in Two-Species Asymmetric Diffusive Processes
We study a stochastic lattice gas of particles undergoing asymmetric
diffusion in two dimensions. Transitions between a low-density uniform phase
and high-density non-uniform phases characterized by localized or extended
structure are found. We develop a mean-field theory which relates
coarse-grained parameters to microscopic ones. Detailed predictions for
finite-size () scaling and density profiles agree excellently with
simulations. Unusual large- behavior of the transition point parallel to
that of self-organized sandpile models is found.Comment: 7 pages, plus 6 figures uuencoded, compressed and appended after
source code, LATeX, to be published as a Phys. Rev. Let
Microwave conductivity in the ferropnictides with specific application to BaKFeAs
We calculate the microwave conductivity of a two band superconductor with
gap symmetry. Inelastic scattering is included approximately in a BCS
model augmented by a temperature dependent quasiparticle scattering rate
assumed, however, to be frequency independent. The possibility that the s-wave
gap on one or the other of the electron or hole pockets is anisotropic is
explored including cases with and without gap nodes on the Fermi surface. A
comparison of our BCS results with those obtained in the Two Fluid Model (TFM)
is provided as well as with the case of the cuprates where the gap has d-wave
symmetry and with experimental results in BaKFeAs. The
presently available microwave conductivity data in this material provides
strong evidence for large anisotropies in the electron pocket s-wave gap. While
a best fit favors a gap with nodes on the Fermi surface this disagrees with
some but not all penetration depth measurements which would favor a node-less
gap as do also thermal conductivity and nuclear magnetic resonance data.Comment: 12 pages, 9 figures. Phys. Rev. B (submitted
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