227,095 research outputs found
Joint Bayesian Gaussian discriminant analysis for speaker verification
State-of-the-art i-vector based speaker verification relies on variants of
Probabilistic Linear Discriminant Analysis (PLDA) for discriminant analysis. We
are mainly motivated by the recent work of the joint Bayesian (JB) method,
which is originally proposed for discriminant analysis in face verification. We
apply JB to speaker verification and make three contributions beyond the
original JB. 1) In contrast to the EM iterations with approximated statistics
in the original JB, the EM iterations with exact statistics are employed and
give better performance. 2) We propose to do simultaneous diagonalization (SD)
of the within-class and between-class covariance matrices to achieve efficient
testing, which has broader application scope than the SVD-based efficient
testing method in the original JB. 3) We scrutinize similarities and
differences between various Gaussian PLDAs and JB, complementing the previous
analysis of comparing JB only with Prince-Elder PLDA. Extensive experiments are
conducted on NIST SRE10 core condition 5, empirically validating the
superiority of JB with faster convergence rate and 9-13% EER reduction compared
with state-of-the-art PLDA.Comment: accepted by ICASSP201
Testing for Homogeneity with Kernel Fisher Discriminant Analysis
We propose to investigate test statistics for testing homogeneity in
reproducing kernel Hilbert spaces. Asymptotic null distributions under null
hypothesis are derived, and consistency against fixed and local alternatives is
assessed. Finally, experimental evidence of the performance of the proposed
approach on both artificial data and a speaker verification task is provided
Simulation technique for available bandwidth estimation
The paper proposes a method for measuring available bandwidth, based on
testing network packets of various sizes (Variable Packet Size method, VPS).
The boundaries of applicability of the model have been found, which are based
on the accuracy of measurements of packet delays, also we have derived a
formula of measuring the upper limit of bandwidth. The computer simulation has
been performed and relationship between the measurement error of available
bandwidth and the number of measurements has been found. Experimental
verification with the use of RIPE Test Box measuring system has shown that the
suggested method has advantages over existing measurement techniques. Pathload
utility has been chosen as an alternative technique of measurement, and to
ensure reliable results statistics by SNMP agent has been withdrawn directly
from the router
Linear optics schemes for entanglement distribution with realistic single-photon sources
We study the operation of linear optics schemes for entanglement distribution
based on nonlocal photon subtraction when input states, produced by imperfect
single-photon sources, exhibit both vacuum and multiphoton contributions. Two
models for realistic photon statistics with radically different properties of
the multiphoton "tail" are considered. The first model assumes occasional
emission of double photons and linear attenuation, while the second one is
motivated by heralded sources utilizing spontaneous parametric down-conversion.
We find conditions for the photon statistics that guarantee generation of
entanglement in the relevant qubit subspaces and compare it with classicality
criteria. We also quantify the amount of entanglement that can be produced with
imperfect single-photon sources, optimized over setup parameters, using as a
measure entanglement of formation. Finally, we discuss verification of the
generated entanglement by testing Bell's inequalities. The analysis is carried
out for two schemes. The first one is the well-established one-photon scheme,
which produces a photon in a delocalized superposition state between two nodes,
each of them fed with one single photon at the input. As the second scheme, we
introduce and analyze a linear-optics analog of the robust scheme based on
interfering two Stokes photons emitted by atomic ensembles, which does not
require phase stability between the nodes.Comment: 12 pages, 7 figures, title change, minor corrections in the tex
Model Verification and the Likelihood Principle
The likelihood principle (LP) is typically understood as a constraint on any measure of evidence arising from a statistical experiment. It is not sufficiently often noted, however, that the LP assumes that the probability model giving rise to a particular concrete data set must be statistically adequateâit must âfitâ the data sufficiently. In practice, though, scientists must make modeling assumptions whose adequacy can nevertheless then be verified using statistical tests. My present concern is to consider whether the LP applies to these techniques of model verification. If one does view model verification as part of the inferential procedures that the LP intends to constrain, then there are certain crucial tests of model verification that no known method satisfying the LP can perform. But if one does not, the degree to which these assumptions have been verified is bracketed from the evidential evaluation under the LP. Although I conclude from this that the LP cannot be a universal constraint on any measure of evidence, proponents of the LP may hold out for a restricted version thereof, either as a kind of âidealâ or as defining one among many different forms of evidence
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