9,819 research outputs found
EEF: Exponentially Embedded Families with Class-Specific Features for Classification
In this letter, we present a novel exponentially embedded families (EEF)
based classification method, in which the probability density function (PDF) on
raw data is estimated from the PDF on features. With the PDF construction, we
show that class-specific features can be used in the proposed classification
method, instead of a common feature subset for all classes as used in
conventional approaches. We apply the proposed EEF classifier for text
categorization as a case study and derive an optimal Bayesian classification
rule with class-specific feature selection based on the Information Gain (IG)
score. The promising performance on real-life data sets demonstrates the
effectiveness of the proposed approach and indicates its wide potential
applications.Comment: 9 pages, 3 figures, to be published in IEEE Signal Processing Letter.
IEEE Signal Processing Letter, 201
Stabilizing Training of Generative Adversarial Networks through Regularization
Deep generative models based on Generative Adversarial Networks (GANs) have
demonstrated impressive sample quality but in order to work they require a
careful choice of architecture, parameter initialization, and selection of
hyper-parameters. This fragility is in part due to a dimensional mismatch or
non-overlapping support between the model distribution and the data
distribution, causing their density ratio and the associated f-divergence to be
undefined. We overcome this fundamental limitation and propose a new
regularization approach with low computational cost that yields a stable GAN
training procedure. We demonstrate the effectiveness of this regularizer across
several architectures trained on common benchmark image generation tasks. Our
regularization turns GAN models into reliable building blocks for deep
learning
A Local Density-Based Approach for Local Outlier Detection
This paper presents a simple but effective density-based outlier detection
approach with the local kernel density estimation (KDE). A Relative
Density-based Outlier Score (RDOS) is introduced to measure the local
outlierness of objects, in which the density distribution at the location of an
object is estimated with a local KDE method based on extended nearest neighbors
of the object. Instead of using only nearest neighbors, we further consider
reverse nearest neighbors and shared nearest neighbors of an object for density
distribution estimation. Some theoretical properties of the proposed RDOS
including its expected value and false alarm probability are derived. A
comprehensive experimental study on both synthetic and real-life data sets
demonstrates that our approach is more effective than state-of-the-art outlier
detection methods.Comment: 22 pages, 14 figures, submitted to Pattern Recognition Letter
Quantal-Classical Duality and the Semiclassical Trace Formula
We consider Hamiltonian systems which can be described both classically and
quantum mechanically. Trace formulas establish links between the energy spectra
of the quantum description and the spectrum of actions of periodic orbits in
the classical description. This duality is investigated in the present paper.
The duality holds for chaotic as well as for integrable systems. For billiards
the quantal spectrum (eigenvalues of the Helmholtz equation) and the classical
spectrum (lengths of periodic orbits) are two manifestations of the billiard's
boundary. The trace formula expresses this link as a Fourier transform relation
between the corresponding spectral densities. It follows that the two-point
statistics are also simply related. The universal correlations of the quantal
spectrum are well known, consequently one can deduce the classical universal
correlations. An explicit expression for the scale of the classical
correlations is derived and interpreted. This allows a further extension of the
formalism to the case of complex billiard systems, and in particular to the
most interesting case of diffusive system. The concept of classical
correlations allows a better understanding of the so-called diagonal
approximation and its breakdown. It also paves the way towards a semiclassical
theory that is capable of global description of spectral statistics beyond the
breaktime. An illustrative application is the derivation of the
disorder-limited breaktime in case of a disordered chain, thus obtaining a
semiclassical theory for localization. A numerical study of classical
correlations in the case of the 3D Sinai billiard is presented. We gain a
direct understanding of specific statistical properties of the classical
spectrum, as well as their semiclassical manifestation in the quantal spectrum.Comment: 42 pages, 17 figure
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