179 research outputs found
Audio style transfer
'Style transfer' among images has recently emerged as a very active research
topic, fuelled by the power of convolution neural networks (CNNs), and has
become fast a very popular technology in social media. This paper investigates
the analogous problem in the audio domain: How to transfer the style of a
reference audio signal to a target audio content? We propose a flexible
framework for the task, which uses a sound texture model to extract statistics
characterizing the reference audio style, followed by an optimization-based
audio texture synthesis to modify the target content. In contrast to mainstream
optimization-based visual transfer method, the proposed process is initialized
by the target content instead of random noise and the optimized loss is only
about texture, not structure. These differences proved key for audio style
transfer in our experiments. In order to extract features of interest, we
investigate different architectures, whether pre-trained on other tasks, as
done in image style transfer, or engineered based on the human auditory system.
Experimental results on different types of audio signal confirm the potential
of the proposed approach.Comment: ICASSP 2018 - 2018 IEEE International Conference on Acoustics, Speech
and Signal Processing (ICASSP), Apr 2018, Calgary, France. IEE
Heavy Meson Hyperfine Splittings: A Puzzle for Heavy Quark Chiral Perturbation Theory
We show that there is a large discrepancy between the expected light flavor
dependence of the heavy pseudoscalar--vector mass splittings and the measured
values. We demonstrate that the one--loop calculation is unreliable. Moreover,
agreement with experiment requires the leading dependence on SU(3) symmetry
breaking to be nearly cancelled, so that the heavy quark mass dependence is
unknown and the expected dependence on the light quark mass is not realized.Comment: 11 pages (LaTeX, 2 PS figures available upon request), MIT-CTP#216
Graph neural networks for sound source localization on distributed microphone networks
Distributed Microphone Arrays (DMAs) present many challenges with respect to
centralized microphone arrays. An important requirement of applications on
these arrays is handling a variable number of input channels. We consider the
use of Graph Neural Networks (GNNs) as a solution to this challenge. We present
a localization method using the Relation Network GNN, which we show shares many
similarities to classical signal processing algorithms for Sound Source
Localization (SSL). We apply our method for the task of SSL and validate it
experimentally using an unseen number of microphones. We test different feature
extractors and show that our approach significantly outperforms classical
baselines.Comment: Presented as a poster at ICASSP 202
Dual input neural networks for positional sound source localization
In many signal processing applications, metadata may be advantageously used
in conjunction with a high dimensional signal to produce a desired output. In
the case of classical Sound Source Localization (SSL) algorithms, information
from a high dimensional, multichannel audio signals received by many
distributed microphones is combined with information describing acoustic
properties of the scene, such as the microphones' coordinates in space, to
estimate the position of a sound source. We introduce Dual Input Neural
Networks (DI-NNs) as a simple and effective way to model these two data types
in a neural network. We train and evaluate our proposed DI-NN on scenarios of
varying difficulty and realism and compare it against an alternative
architecture, a classical Least-Squares (LS) method as well as a classical
Convolutional Recurrent Neural Network (CRNN). Our results show that the DI-NN
significantly outperforms the baselines, achieving a five times lower
localization error than the LS method and two times lower than the CRNN in a
test dataset of real recordings
QCD Radiative Corrections to the Leptonic Decay Rate of the B_c Meson
The QCD radiative corrections to the leptonic decay rate of the meson
are calculated using the formalism of nonrelativistic QCD (NRQCD) to separate
short-distance and long-distance effects. The decay constant is factored
into a sum of NRQCD matrix elements each multiplied by a short-distance
coefficient. The short-distance coefficient for the leading matrix element is
calculated to order by matching a perturbative calculation in full
QCD with the corresponding perturbative calculation in NRQCD. This
short-distance correction decreases the leptonic decay rate by approximately
.Comment: Changed Eq. 2 to read 1/(8 \pi), put in a missing i M_{B_c} in Eq.
18, and put in a normalisation factor of 2 M_{B_c} in Eq. 19
The Rate for and its Implications for the Study of CP Violation, Identification, and the Study of Meson Chiral Perturbation Theory
H.~Yamamoto has proposed employing mesons produced in conjunction with a
single charged pion at an resonance for studies of CP violation in
the neutral meson system at a symmetric - collider. The sign of
the charged pion would tag the neutral meson. We estimate this branching
ratio, employing the heavy meson chiral effective field theory. We find a
negligible branching ratio to at the (5S) and a
branching ratio of only a few percent at the (6S). However, if
nonresonant studies of neutral mesons should prove feasible, Yamamoto's
proposal could be a good method for tagging neutral 's for the study of CP
violation at a symmetric collider.
We also explore the possibility of studying at the (5S). The
rate is low but depends sensitively on the precise value of the mass of the
. The background we compute is comparable to the rate at the largest
allowed value of the mass.
Finally, we discuss the extraction of the axial pion coupling to mesons
from measurement of the B\bbar\pi branching fraction in a restricted region
of phase space, where chiral perturbation theory should work well.Comment: 32 pages, 3 PS figures available upon request, MIT-CTP#215
B Production Asymmetries in Perturbative QCD
This paper explores a new mechanism for B production in which a b quark
combines with a light parton from the hard-scattering process before
hadronizing into the B hadron. This recombination mechanism can be calculated
within perturbative QCD up to a few nonperturbative constants. Though
suppressed at large transverse momentum by a factor Lambda_QCD m_b/p_t^2
relative to b quark fragmentation production, it can be important at large
rapidities. A signature for this heavy-quark recombination mechanism in
proton-antiproton colliders is the presence of rapidity asymmetries in B cross
sections. Given reasonable assumptions about the size of nonperturbative
parameters entering the calculation, we find that the asymmetries are only
significant for rapidities larger than those currently probed by collider
experiments.Comment: 17 pages, LaTeX, 4 ps figures, tightenlines, sections added, final
version accepted for publication in Phys. Rev.
iPSCORE: A Resource of 222 iPSC Lines Enabling Functional Characterization of Genetic Variation across a Variety of Cell Types.
Large-scale collections of induced pluripotent stem cells (iPSCs) could serve as powerful model systems for examining how genetic variation affects biology and disease. Here we describe the iPSCORE resource: a collection of systematically derived and characterized iPSC lines from 222 ethnically diverse individuals that allows for both familial and association-based genetic studies. iPSCORE lines are pluripotent with high genomic integrity (no or low numbers of somatic copy-number variants) as determined using high-throughput RNA-sequencing and genotyping arrays, respectively. Using iPSCs from a family of individuals, we show that iPSC-derived cardiomyocytes demonstrate gene expression patterns that cluster by genetic background, and can be used to examine variants associated with physiological and disease phenotypes. The iPSCORE collection contains representative individuals for risk and non-risk alleles for 95% of SNPs associated with human phenotypes through genome-wide association studies. Our study demonstrates the utility of iPSCORE for examining how genetic variants influence molecular and physiological traits in iPSCs and derived cell lines
Large-deviation principles, stochastic effective actions, path entropies, and the structure and meaning of thermodynamic descriptions
The meaning of thermodynamic descriptions is found in large-deviations
scaling of the fluctuations probabilities. The primary large-deviations rate
function is the entropy, which is the basis for both fluctuation theorems and
for characterizing the thermodynamic interactions of systems. Freidlin-Wentzell
theory provides a general formulation of large-deviations scaling for
non-equilibrium stochastic processes, through a representation in terms of a
Hamiltonian dynamical system. A number of related methods now exist to
construct the Freidlin-Wentzell Hamiltonian for many kinds of stochastic
processes; one method due to Doi and Peliti, appropriate to integer counting
statistics, is widely used in reaction-diffusion theory.
Using these tools together with a path-entropy method due to Jaynes, we show
how to construct entropy functions that both express large-deviations scaling
of fluctuations, and describe system-environment interactions, for discrete
stochastic processes either at or away from equilibrium. A collection of
variational methods familiar within quantum field theory, but less commonly
applied to the Doi-Peliti construction, is used to define a "stochastic
effective action", which is the large-deviations rate function for arbitrary
non-equilibrium paths.
We show how common principles of entropy maximization, applied to different
ensembles of states or of histories, lead to different entropy functions and
different sets of thermodynamic state variables. Yet the relations of among all
these levels of description may be constructed explicitly and understood in
terms of information conditions. The example systems considered introduce
methods that may be used to systematically construct descriptions with all the
features familiar from equilibrium thermodynamics, for a much wider range of
systems describable by stochastic processes
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