4,500 research outputs found
Self-Supervised Audio-Visual Co-Segmentation
Segmenting objects in images and separating sound sources in audio are
challenging tasks, in part because traditional approaches require large amounts
of labeled data. In this paper we develop a neural network model for visual
object segmentation and sound source separation that learns from natural videos
through self-supervision. The model is an extension of recently proposed work
that maps image pixels to sounds. Here, we introduce a learning approach to
disentangle concepts in the neural networks, and assign semantic categories to
network feature channels to enable independent image segmentation and sound
source separation after audio-visual training on videos. Our evaluations show
that the disentangled model outperforms several baselines in semantic
segmentation and sound source separation.Comment: Accepted to ICASSP 201
DIVE in the cosmic web: voids with Delaunay Triangulation from discrete matter tracer distributions
We present a novel parameter-free cosmological void finder (\textsc{dive},
Delaunay TrIangulation Void findEr) based on Delaunay Triangulation (DT), which
efficiently computes the empty spheres constrained by a discrete set of
tracers. We define the spheres as DT voids, and describe their properties,
including an universal density profile together with an intrinsic scatter. We
apply this technique on 100 halo catalogues with volumes of 2.5\,Gpc
side each, with a bias and number density similar to the BOSS CMASS Luminous
Red Galaxies, performed with the \textsc{patchy} code. Our results show that
there are two main species of DT voids, which can be characterised by the
radius: they have different responses to halo redshift space distortions, to
number density of tracers, and reside in different dark matter environments.
Based on dynamical arguments using the tidal field tensor, we demonstrate that
large DT voids are hosted in expanding regions, whereas the haloes used to
construct them reside in collapsing ones. Our approach is therefore able to
efficiently determine the troughs of the density field from galaxy surveys, and
can be used to study their clustering. We further study the power spectra of DT
voids, and find that the bias of the two populations are different,
demonstrating that the small DT voids are essentially tracers of groups of
haloes.Comment: 12 pages, 13 figure
The clustering of galaxies in the completed SDSS-III Baryon Oscillation Spectroscopic Survey: a tomographic analysis of structure growth and expansion rate from anisotropic galaxy clustering
We perform a tomographic analysis of structure growth and expansion rate from
the anisotropic galaxy clustering of the combined sample of Baryon Oscillation
Spectroscopic Survey (BOSS) Data Release 12, which covers the redshift range of
. In order to extract the redshift information of anisotropic
galaxy clustering, we analyse this data set in nine overlapping redshift slices
in configuration space and perform the joint constraints on the parameters
using the correlation function multipoles.
The analysis pipeline is validated using the MultiDark-Patchy mock catalogues.
We obtain a measurement precision of for , for
and for , depending on the
effective redshift of the slices. We report a joint measurement of with the full covariance matrix in nine redshift
slices. We use our joint BAO and RSD measurement combined with external
datasets to constrain the gravitational growth index , and find
, which is consistent with the CDM prediction
within 95\% CL.Comment: 8 pages, 8 figures, 2 tables, accepted for publication MNRAS. The
measured results including the full covariance matrices are made available at
https://github.com/ytcosmo/TomoBAORSD and tomographic clustering data used in
this work is available at https://sdss3.org//science/boss_publications.ph
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