5,086 research outputs found
Constraining Absolute Neutrino Masses via Detection of Galactic Supernova Neutrinos at JUNO
A high-statistics measurement of the neutrinos from a galactic core-collapse
supernova is extremely important for understanding the explosion mechanism, and
studying the intrinsic properties of neutrinos themselves. In this paper, we
explore the possibility to constrain the absolute scale of neutrino masses
via the detection of galactic supernova neutrinos at the Jiangmen
Underground Neutrino Observatory (JUNO) with a 20 kiloton liquid-scintillator
detector. In assumption of a nearly-degenerate neutrino mass spectrum and a
normal mass ordering, the upper bound on the absolute neutrino mass is found to
be at the 95% confidence level for a
typical galactic supernova at a distance of 10 kpc, where the mean value and
standard deviation are shown to account for statistical fluctuations. For
comparison, we find that the bound in the Super-Kamiokande experiment is
at the same confidence level. However,
the upper bound will be relaxed when the model parameters characterizing the
time structure of supernova neutrino fluxes are not exactly known, and when the
neutrino mass ordering is inverted.Comment: 22 pages, 6 figures, more discussions on systematic uncertainties,
matches the published versio
Accelerating Message Passing for MAP with Benders Decomposition
We introduce a novel mechanism to tighten the local polytope relaxation for
MAP inference in Markov random fields with low state space variables. We
consider a surjection of the variables to a set of hyper-variables and apply
the local polytope relaxation over these hyper-variables. The state space of
each individual hyper-variable is constructed to be enumerable while the vector
product of pairs is not easily enumerable making message passing inference
intractable.
To circumvent the difficulty of enumerating the vector product of state
spaces of hyper-variables we introduce a novel Benders decomposition approach.
This produces an upper envelope describing the message constructed from affine
functions of the individual variables that compose the hyper-variable receiving
the message. The envelope is tight at the minimizers which are shared by the
true message. Benders rows are constructed to be Pareto optimal and are
generated using an efficient procedure targeted for binary problems
Covariance Estimation in High Dimensions via Kronecker Product Expansions
This paper presents a new method for estimating high dimensional covariance
matrices. The method, permuted rank-penalized least-squares (PRLS), is based on
a Kronecker product series expansion of the true covariance matrix. Assuming an
i.i.d. Gaussian random sample, we establish high dimensional rates of
convergence to the true covariance as both the number of samples and the number
of variables go to infinity. For covariance matrices of low separation rank,
our results establish that PRLS has significantly faster convergence than the
standard sample covariance matrix (SCM) estimator. The convergence rate
captures a fundamental tradeoff between estimation error and approximation
error, thus providing a scalable covariance estimation framework in terms of
separation rank, similar to low rank approximation of covariance matrices. The
MSE convergence rates generalize the high dimensional rates recently obtained
for the ML Flip-flop algorithm for Kronecker product covariance estimation. We
show that a class of block Toeplitz covariance matrices is approximatable by
low separation rank and give bounds on the minimal separation rank that
ensures a given level of bias. Simulations are presented to validate the
theoretical bounds. As a real world application, we illustrate the utility of
the proposed Kronecker covariance estimator for spatio-temporal linear least
squares prediction of multivariate wind speed measurements.Comment: 47 pages, accepted to IEEE Transactions on Signal Processin
Quasi-hyperbolic momentum and Adam for deep learning
Momentum-based acceleration of stochastic gradient descent (SGD) is widely
used in deep learning. We propose the quasi-hyperbolic momentum algorithm (QHM)
as an extremely simple alteration of momentum SGD, averaging a plain SGD step
with a momentum step. We describe numerous connections to and identities with
other algorithms, and we characterize the set of two-state optimization
algorithms that QHM can recover. Finally, we propose a QH variant of Adam
called QHAdam, and we empirically demonstrate that our algorithms lead to
significantly improved training in a variety of settings, including a new
state-of-the-art result on WMT16 EN-DE. We hope that these empirical results,
combined with the conceptual and practical simplicity of QHM and QHAdam, will
spur interest from both practitioners and researchers. Code is immediately
available.Comment: Published as a conference paper at ICLR 2019. This version corrects
one typological error in the published tex
Generalization Error in Deep Learning
Deep learning models have lately shown great performance in various fields
such as computer vision, speech recognition, speech translation, and natural
language processing. However, alongside their state-of-the-art performance, it
is still generally unclear what is the source of their generalization ability.
Thus, an important question is what makes deep neural networks able to
generalize well from the training set to new data. In this article, we provide
an overview of the existing theory and bounds for the characterization of the
generalization error of deep neural networks, combining both classical and more
recent theoretical and empirical results
Neutrinos and Future Concordance Cosmologies
We review the free parameters in the concordance cosmology, and those which
might be added to this set as the quality of astrophysical data improves. Most
concordance parameters encode information about otherwise unexplored aspects of
high energy physics, up to the GUT scale via the "inflationary sector," and
possibly even the Planck scale in the case of dark energy. We explain how
neutrino properties may be constrained by future astrophysical measurements.
Conversely, future neutrino physics experiments which directly measure these
parameters will remove uncertainty from fits to astrophysical data, and improve
our ability to determine the global properties of our universe.Comment: Proceedings of paper given at Neutrino 2008 meeting (by RE
A Fast Scalable Heuristic for Bin Packing
In this paper we present a fast scalable heuristic for bin packing that
partitions the given problem into identical sub-problems of constant size and
solves these constant size sub-problems by considering only a constant number
of bin configurations with bounded unused space. We present some empirical
evidence to support the scalability of our heuristic and its tighter empirical
analysis of hard instances due to improved lower bound on the necessary wastage
in an optimal solution.Comment: 16 pages. arXiv admin note: text overlap with arXiv:1902.0342
Harmless interpolation of noisy data in regression
A continuing mystery in understanding the empirical success of deep neural
networks is their ability to achieve zero training error and generalize well,
even when the training data is noisy and there are more parameters than data
points. We investigate this overparameterized regime in linear regression,
where all solutions that minimize training error interpolate the data,
including noise. We characterize the fundamental generalization (mean-squared)
error of any interpolating solution in the presence of noise, and show that
this error decays to zero with the number of features. Thus,
overparameterization can be explicitly beneficial in ensuring harmless
interpolation of noise. We discuss two root causes for poor generalization that
are complementary in nature -- signal "bleeding" into a large number of alias
features, and overfitting of noise by parsimonious feature selectors. For the
sparse linear model with noise, we provide a hybrid interpolating scheme that
mitigates both these issues and achieves order-optimal MSE over all possible
interpolating solutions.Comment: 52 pages, expanded version of the paper presented at ITA in San Diego
in Feb 2019, ISIT in Paris in July 2019, at Simons in July, and as a plenary
at ITW in Visby in August 201
Chanel No5 (fb^-1): The Sweet Fragrance of SUSY
We present compounding evidence of supersymmetry (SUSY) production at the
LHC, in the form of correlations between the nominal 5\fb ATLAS and CMS results
for the 7 TeV 2011 run and detailed Monte Carlo collider-detector simulation of
a concrete supersymmetric model named No-Scale F-SU(5). Restricting analysis to
those event selections which yield a signal significance S/sqrt(B+1) greater
than 2, we find by application of the \chi^2 statistic that strong correlations
exist among the individual search strategies and also between the current best
fit to the SUSY mass scale and that achieved using historical 1\fb data sets.
Coupled with an appropriately large increase in the "depth" of the \chi^2 well
with increasing luminosity, we suggest that these features indicate the
presence of a non-random structure to the data - a light fragrance perhaps
evocative of some fuller coming fruition. Those searches having signal
significances below 2 are assembled into a lower exclusion bound on the gaugino
mass, which is shown to be consistent with the prior best fit. Assuming the
forthcoming delivery of an additional tranche of integrated luminosity at 8 TeV
during 2012 that measures on the order 15\fb, we project a sufficiency of
actionable data to conclusively judge the merits of our proposal.Comment: 8 Pages, 2 Figures, 1 Tabl
Analysis of multivariate Gegenbauer approximation in the hypercube
In this paper, we are concerned with multivariate Gegenbauer approximation of
functions defined in the -dimensional hypercube. Two new and sharper bounds
for the coefficients of multivariate Gegenbauer expansion of analytic functions
are presented based on two different extensions of the Bernstein ellipse. We
then establish an explicit error bound for the multivariate Gegenbauer
approximation associated with an ball index set in the uniform norm.
We also consider the multivariate approximation of functions with finite
regularity and derive the associated error bound on the full grid in the
uniform norm. As an application, we extend our arguments to obtain some new
tight bounds for the coefficients of tensorized Legendre expansions in the
context of polynomial approximation of parameterized PDEs.Comment: Adv. Comput. Math., to appea
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