52,391 research outputs found
Kinetics of Open Circuit Processes in Undischarged Li/SOC12 Cells
The kinetics of the heat producing processes in undischarged Li/SOCl2 cells under open circuit conditions were measured by heat-conduction microcalorimetry. The cells studied, Honeywell type G2666 reserve cells, were activated as needed and the rate of open circuit heat output determined as a function of time since activation and temperature. The results at each temperature can be described by an equation of the form q = Bktx where q is the rate of heat output, B is the heat produced per unit of reaction, k and x are empirical constants, and t is the time since activation. Both x and k are found to be functions of temperature; therefore, accelerated testing at elevated temperatures is probably not valid for these cells until the processes involved are better understood
Leveraging native language information for improved accented speech recognition
Recognition of accented speech is a long-standing challenge for automatic
speech recognition (ASR) systems, given the increasing worldwide population of
bi-lingual speakers with English as their second language. If we consider
foreign-accented speech as an interpolation of the native language (L1) and
English (L2), using a model that can simultaneously address both languages
would perform better at the acoustic level for accented speech. In this study,
we explore how an end-to-end recurrent neural network (RNN) trained system with
English and native languages (Spanish and Indian languages) could leverage data
of native languages to improve performance for accented English speech. To this
end, we examine pre-training with native languages, as well as multi-task
learning (MTL) in which the main task is trained with native English and the
secondary task is trained with Spanish or Indian Languages. We show that the
proposed MTL model performs better than the pre-training approach and
outperforms a baseline model trained simply with English data. We suggest a new
setting for MTL in which the secondary task is trained with both English and
the native language, using the same output set. This proposed scenario yields
better performance with +11.95% and +17.55% character error rate gains over
baseline for Hispanic and Indian accents, respectively.Comment: Accepted at Interspeech 201
Scaled Particle Theory for Hard Sphere Pairs. I. Mathematical Structure
We develop an extension of the original Reiss-Frisch-Lebowitz scaled particle
theory that can serve as a predictive method for the hard sphere pair
correlation function g(r). The reversible cavity creation work is analyzed both
for a single spherical cavity of arbitrary size, as well as for a pair of
identical such spherical cavities with variable center-to-center separation.
These quantities lead directly to prediction of g(r). Smooth connection
conditions have been identified between the small-cavity situation where the
work can be exactly and completely expressed in terms of g(r), and the
large-cavity regime where macroscopic properties become relevant. Closure
conditions emerge which produce a nonlinear integral equation that must be
satisfied by the pair correlation function. This integral equation has a
structure which straightforwardly generates a solution that is a power series
in density. The results of this series replicate the exact second and third
virial coefficients for the hard sphere system via the contact value of the
pair correlation function. The predicted fourth virial coefficient is
approximately 0.6 percent lower than the known exact value. Detailed numerical
analysis of the nonlinear integral equation has been deferred to the sequel
(following paper
A Speaker Diarization System for Studying Peer-Led Team Learning Groups
Peer-led team learning (PLTL) is a model for teaching STEM courses where
small student groups meet periodically to collaboratively discuss coursework.
Automatic analysis of PLTL sessions would help education researchers to get
insight into how learning outcomes are impacted by individual participation,
group behavior, team dynamics, etc.. Towards this, speech and language
technology can help, and speaker diarization technology will lay the foundation
for analysis. In this study, a new corpus is established called CRSS-PLTL, that
contains speech data from 5 PLTL teams over a semester (10 sessions per team
with 5-to-8 participants in each team). In CRSS-PLTL, every participant wears a
LENA device (portable audio recorder) that provides multiple audio recordings
of the event. Our proposed solution is unsupervised and contains a new online
speaker change detection algorithm, termed G 3 algorithm in conjunction with
Hausdorff-distance based clustering to provide improved detection accuracy.
Additionally, we also exploit cross channel information to refine our
diarization hypothesis. The proposed system provides good improvements in
diarization error rate (DER) over the baseline LIUM system. We also present
higher level analysis such as the number of conversational turns taken in a
session, and speaking-time duration (participation) for each speaker.Comment: 5 Pages, 2 Figures, 2 Tables, Proceedings of INTERSPEECH 2016, San
Francisco, US
Infall near clusters of galaxies: comparing gas and dark matter velocity profiles
We consider the dynamics in and near galaxy clusters. Gas, dark matter and
galaxies are presently falling into the clusters between approximately 1 and 5
virial radii. At very large distances, beyond 10 virial radii, all matter is
following the Hubble flow, and inside the virial radius the matter particles
have on average zero radial velocity. The cosmological parameters are imprinted
on the infall profile of the gas, however, no method exists, which allows a
measurement of it. We consider the results of two cosmological simulations
(using the numerical codes RAMSES and Gadget) and find that the gas and dark
matter radial velocities are very similar. We derive the relevant dynamical
equations, in particular the generalized hydrostatic equilibrium equation,
including both the expansion of the Universe and the cosmological background.
This generalized gas equation is the main new contribution of this paper. We
combine these generalized equations with the results of the numerical
simulations to estimate the contribution to the measured cluster masses from
the radial velocity: inside the virial radius it is negligible, and inside two
virial radii the effect is below 40%, in agreement the earlier analyses for DM.
We point out how the infall velocity in principle may be observable, by
measuring the gas properties to distance of about two virial radii, however,
this is practically not possible today.Comment: 7 pages, 3 figures, to appear in MNRA
Toward the Jamming Threshold of Sphere Packings: Tunneled Crystals
We have discovered a new family of three-dimensional crystal sphere packings
that are strictly jammed (i.e., mechanically stable) and yet possess an
anomalously low density. This family constitutes an uncountably infinite number
of crystal packings that are subpackings of the densest crystal packings and
are characterized by a high concentration of self-avoiding "tunnels" (chains of
vacancies) that permeate the structures. The fundamental geometric
characteristics of these tunneled crystals command interest in their own right
and are described here in some detail. These include the lattice vectors (that
specify the packing configurations), coordination structure, Voronoi cells, and
density fluctuations. The tunneled crystals are not only candidate structures
for achieving the jamming threshold (lowest-density rigid packing), but may
have substantially broader significance for condensed matter physics and
materials science.Comment: 19 pages, 5 figure
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