57,817 research outputs found
System and method for character recognition
A character recognition system is disclosed in which each character in a retina, defining a scanning raster, is scanned with random lines uniformly distributed over the retina. For each type of character to be recognized the system stores a probability density function (PDF) of the random line intersection lengths and/or a PDF of the random line number of intersections. As an unknown character is scanned, the random line intersection lengths and/or the random line number of intersections are accumulated and based on a comparison with the prestored PDFs a classification of the unknown character is performed
Pattern recognition technique
Technique operates regardless of pattern rotation, translation or magnification and successfully detects out-of-register patterns. It improves accuracy and reduces cost of various optical character recognition devices and page readers and provides data input to computer
Real time analysis of voiced sounds
A power spectrum analysis of the harmonic content of a voiced sound signal is conducted in real time by phase-lock-loop tracking of the fundamental frequency, (f sub 0) of the signal and successive harmonics (h sub 1 through h sub n) of the fundamental frequency. The analysis also includes measuring the quadrature power and phase of each frequency tracked, differentiating the power measurements of the harmonics in adjacent pairs, and analyzing successive differentials to determine peak power points in the power spectrum for display or use in analysis of voiced sound, such as for voice recognition
Quantitative Description of by the Hubbard Model in Infinite Dimensions
We show that the analytic single-particle density of states and the optical
conductivity for the half-filled Hubbard model on the Bethe lattice in infinite
dimensions describe quantitatively the behavior of the gap and the kinetic
energy ratio of the correlated insulator . The form of the optical
conductivity shows rising and is quite similar to the
experimental data, and the density of states shows behavior near
the band edges.Comment: 9 pages, revtex, 4 figures upon reques
Many-body Green's function theory of ferromagnetic Heisenberg systems with single-ion anisotropies in more than one direction
The behaviour of ferromagnetic systems with single-ion anisotropies in more
than one direction is investigated with many-body Green's function theory
generalizing earlier work with uniaxial anisotropies only. It turns out to be
of advantage to construct Green's functions in terms of the spin operators S^x,
S^y and S^z, instead of the commonly used S^+,S^- and S^z operators. The
exchange energy terms are decoupled by RPA and the single-ion anisotropy terms
by a generalization of the Anderson-Callen decoupling. We stress that in the
derivation of the formalism none of the three spatial axes is special, so that
one is always able to select a reference direction along which a magnetization
component is not zero. Analytical expressions are obtained for all three
components of the magnetization and the expectation values ,
and for any spin quantum number S. The formalism considers both
in-plane and out-of-plane anisotropies. Numerical calculations illustrate the
behaviour of the magnetization for 3-dimensional and 2-dimensional systems for
various parameters. In the 2-dimensional case, the magnetic dipole-dipole
coupling is included, and a comparison is made between in-plane and
out-of-plane anisotropies.Comment: 16 pages, 8 figures, missing figures adde
A strategic study of energy efficient and hybrid energy system options for a multi-family building in Korea
This study is to identify performance of energy efficiency measures and to match low-carbon and renewable energy (RE) systems supplies to demands in the context of multi-family residential buildings in Korea. An approach to the evaluation of the hybrid energy systems was investigated, including consideration of heat and power demand profiles, energy system combinations, building design options and strategies for matching supply to demand. The approach is encapsulated within an integrated software environment. Building energy simulation technology was exploited to make virtual energy use data. Low-carbon and RE system modelling techniques were used to predict energy supply profiles. A series of demand/supply matching-based analyses were made to identify the effect of energy efficient demand measures (e.g. roof-top gardens, innovative underfloor heating system) and evaluate the capacity utilisation factor from the hybrid energy systems. On the basis of performance information obtained at the conceptual design stage, the design team can pinpoint the most energy efficient demand/supply combination, and consequently, maximise the impact of hybrid energy systems adoption
Provable Deterministic Leverage Score Sampling
We explain theoretically a curious empirical phenomenon: "Approximating a
matrix by deterministically selecting a subset of its columns with the
corresponding largest leverage scores results in a good low-rank matrix
surrogate". To obtain provable guarantees, previous work requires randomized
sampling of the columns with probabilities proportional to their leverage
scores.
In this work, we provide a novel theoretical analysis of deterministic
leverage score sampling. We show that such deterministic sampling can be
provably as accurate as its randomized counterparts, if the leverage scores
follow a moderately steep power-law decay. We support this power-law assumption
by providing empirical evidence that such decay laws are abundant in real-world
data sets. We then demonstrate empirically the performance of deterministic
leverage score sampling, which many times matches or outperforms the
state-of-the-art techniques.Comment: 20th ACM SIGKDD Conference on Knowledge Discovery and Data Minin
Radiation generated by accelerating and rotating charged black holes in (anti-)de Sitter space
Asymptotic behaviour of gravitational and electromagnetic fields of exact
type D solutions from the large Plebanski-Demianski family of black hole
spacetimes is analyzed. The amplitude and directional structure of radiation is
evaluated in cases when the cosmological constant is non-vanishing, so that the
conformal infinities have either de Sitter-like or anti-de Sitter-like
character. In particular, explicit relations between the parameters that
characterize the sources (that is their mass, electric and magnetic charges,
NUT parameter, rotational parameter, and acceleration) and properties of the
radiation generated by them are presented. The results further elucidate the
physical interpretation of these solutions and may help to understand radiative
characteristics of more general spacetimes than those that are asymptotically
flat.Comment: 24 pages, 18 figures. To appear in Classical and Quantum Gravit
Spectral Representation Theory for Dielectric Behavior of Nonspherical Cell Suspensions
Recent experiments revealed that the dielectric dispersion spectrum of
fission yeast cells in a suspension was mainly composed of two sub-dispersions.
The low-frequency sub-dispersion depended on the cell length, while the
high-frequency one was independent of it. The cell shape effect was simulated
by an ellipsoidal cell model but the comparison between theory and experiment
was far from being satisfactory. Prompted by the discrepancy, we proposed the
use of spectral representation to analyze more realistic cell models. We
adopted a shell-spheroidal model to analyze the effects of the cell membrane.
It is found that the dielectric property of the cell membrane has only a minor
effect on the dispersion magnitude ratio and the characteristic frequency
ratio. We further included the effect of rotation of dipole induced by an
external electric field, and solved the dipole-rotation spheroidal model in the
spectral representation. Good agreement between theory and experiment has been
obtained.Comment: 19 pages, 5 eps figure
BRST extension of the Faddeev model
The Faddeev model is a second class constrained system. Here we construct its
nilpotent BRST operator and derive the ensuing manifestly BRST invariant
Lagrangian. Our construction employs the structure of Stuckelberg fields in a
nontrivial fashion.Comment: 4 pages, new references adde
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