4,434 research outputs found
Analysis, Visualization, and Transformation of Audio Signals Using Dictionary-based Methods
date-added: 2014-01-07 09:15:58 +0000 date-modified: 2014-01-07 09:15:58 +0000date-added: 2014-01-07 09:15:58 +0000 date-modified: 2014-01-07 09:15:58 +000
Analysis, visualization, and transformation of audio signals using dictionary-based methods
This article provides an overview of dictionary-based methods (DBMs), and reviews recent work in the application of such methods to working with audio and music signals. As Fourier analysis is to additive synthesis, DBMs can be seen as the analytical counterpart to a generalized granular synthesis, where a sound is built by combining heterogeneous atoms selected from a user-defined dictionary. As such, DBMs provide novel ways for analyzing and visualizing audio signals, creating multiresolution descriptions of their contents, and designing sound transformations unique to a description of audio in terms of atoms. 1
Cosmology with intensity mapping techniques using atomic and molecular lines
We present a systematic study of the intensity mapping technique using
updated models for the different emission lines from galaxies and identify
which ones are more promising for cosmological studies of the post reionization
epoch. We consider the emission of , , H,
optical and infrared oxygen lines, nitrogen lines, CII and the CO rotational
lines. We then identify that , , OII, CII and
the lowest rotational CO lines are the best candidates to be used as IM probes.
These lines form a complementary set of probes of the galaxies emission
spectra. We then use reasonable experimental setups from current, planned or
proposed experiments to access the detectability of the power spectrum of each
emission line. Intensity mapping of emission from to 3
will be possible in the near future with HETDEX, while far-infrared lines
require new dedicated experiments. We also show that the proposed SPHEREx
satellite can use OII and IM to study the large-scale
distribution of matter in intermediate redshifts of 1 to 4. We found that
submilimeter experiments with bolometers can have similar performances at
intermediate redshifts using CII and CO(3-2).Comment: 18 pages, 21 figures, 5 tables, published in MNRAS, typos correcte
Toward a numerical deshaker for PFS
The Planetary Fourier Spectrometer (PFS) onboard Mars Express (MEx) is the
instrument with the highest spectral resolution observing Mars from orbit since
January 2004. It permits studying the atmospheric structure, major and minor
compounds. The present time version of the calibration is limited by the
effects of mechanical vibration, currently not corrected. We proposed here a
new approach to correct for the vibrations based on semi-blind deconvolution of
the measurements. This new approach shows that a correction can be done
efficiently with 85% reduction of the artefacts, in a equivalent manner to the
stacking of 10 spectra. Our strategy is not fully automatic due to the
dependence on some regularisation parameters. It may be applied on the complete
PFS dataset, correcting the large-scale perturbation due to microvibrations for
each spectrum independently. This approach is validated on actual PFS data of
Short Wavelength Channel (SWC), perturbed by microvibrations. A coherence check
can be performed and also validate our approach. Unfortunately, the coherence
check can be done only on the first 310 orbits of MEx only, until the laser
line has been switch off. More generally, this work may apply to numerically
"deshake" Fourier Transform Spectrometer (FTS), widely used in space
experiments or in the laboratory.Comment: 18 pages, 8 figures, submitted to Planetary and Space Scienc
Accurate Light Field Depth Estimation with Superpixel Regularization over Partially Occluded Regions
Depth estimation is a fundamental problem for light field photography
applications. Numerous methods have been proposed in recent years, which either
focus on crafting cost terms for more robust matching, or on analyzing the
geometry of scene structures embedded in the epipolar-plane images. Significant
improvements have been made in terms of overall depth estimation error;
however, current state-of-the-art methods still show limitations in handling
intricate occluding structures and complex scenes with multiple occlusions. To
address these challenging issues, we propose a very effective depth estimation
framework which focuses on regularizing the initial label confidence map and
edge strength weights. Specifically, we first detect partially occluded
boundary regions (POBR) via superpixel based regularization. Series of
shrinkage/reinforcement operations are then applied on the label confidence map
and edge strength weights over the POBR. We show that after weight
manipulations, even a low-complexity weighted least squares model can produce
much better depth estimation than state-of-the-art methods in terms of average
disparity error rate, occlusion boundary precision-recall rate, and the
preservation of intricate visual features
Composite dark matter from a model with composite Higgs boson
In a previous paper \cite{Khlopov:2007ic}, we showed how the minimal walking
technicolor model (WTC) can provide a composite dark matter candidate, by
forming bound states between a -2 electrically charged techniparticle and a
. We studied the properties of these \emph{techni-O-helium}
"atoms", which behave as warmer dark matter rather than cold. In this paper we
extend our work on several different aspects. We study the possibility of a
mixed scenario where both and bound states between +2 and -2
electrically charged techniparticles coexist in the dark matter density. We
argue that these newly proposed bound states solely made of techniparticles,
although they behave as Weakly Interacting Massive Particles (WIMPs), due to
their large elastic cross section with nuclei, can only account for a small
percentage of the dark matter density. Therefore we conclude that within the
minimal WTC, composite dark matter should be mostly composed of .
Moreover in this paper, we put cosmological bounds in the masses of the
techniparticles, if they compose the dark matter density. Finally we propose
within this setup, a possible explanation of the discrepancy between the
DAMA/NaI and DAMA/LIBRA findings and the negative results of CDMS and other
direct dark matter searches that imply nuclear recoil measurement, which should
accompany ionization.Comment: 23 page
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