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An EM Algorithm for Localizing Multiple Sound: Sources in Reverberant Environments
We present a method for localizing and separating sound sources in stereo recordings that is robust to reverberation and does not make any assumptions about the source statistics. The method consists of a probabilistic model of binaural multisource recordings and an expectation maximization algorithm for finding the maximum likelihood parameters of that model. These parameters include distributions over delays and assignments of time-frequency regions to sources. We evaluate this method against two comparable algorithms on simulations of simultaneous speech from two or three sources. Our method outperforms the others in anechoic conditions and performs as well as the better of the two in the presence of reverberation
Association between hours worked in paid employment and diet quality, frequency of eating out and consuming takeaways in the UK
Acknowledgements: The authors thank Altea LorenzoArribas for assistance with the statistical analysis. Financial support: This work was supported by the Scottish Government Rural and Environment Science and Analytical Services (RESAS) division. RESAS had no role in the design, analysis or writing of this article.Peer reviewedPostprintPublisher PD
Effect of different food groups on energy intake within and between individuals
This work was supported by The Scottish Government's Rural and Environment Science and Analytical Services Division (RESAS).Peer reviewedPublisher PD
Prediction of strong shock structure using the bimodal distribution function
A modified Mott-Smith method for predicting the one-dimensional shock wave
solution at very high Mach numbers is constructed by developing a system of
fluid dynamic equations. The predicted shock solutions in a gas of Maxwell
molecules, a hard sphere gas and in argon using the newly proposed formalism
are compared with the experimental data, direct-simulation Monte Carlo (DSMC)
solution and other solutions computed from some existing theories for Mach
numbers M<50. In the limit of an infinitely large Mach number, the predicted
shock profiles are also compared with the DSMC solution. The density,
temperature and heat flux profiles calculated at different Mach numbers have
been shown to have good agreement with the experimental and DSMC solutionsComment: 22 pages, 9 figures, Accepted for publication in Physical Review
Modelling population responses to workplace minimum dietary standards introduced as workers return after social lockdowns
Funding This work was funded by the Scottish Government’s Rural and Environment Science Analytical Services Strategic Research Programme.Peer reviewedPublisher PD
Multiscale Computations on Neural Networks: From the Individual Neuron Interactions to the Macroscopic-Level Analysis
We show how the Equation-Free approach for multi-scale computations can be
exploited to systematically study the dynamics of neural interactions on a
random regular connected graph under a pairwise representation perspective.
Using an individual-based microscopic simulator as a black box coarse-grained
timestepper and with the aid of simulated annealing we compute the
coarse-grained equilibrium bifurcation diagram and analyze the stability of the
stationary states sidestepping the necessity of obtaining explicit closures at
the macroscopic level. We also exploit the scheme to perform a rare-events
analysis by estimating an effective Fokker-Planck describing the evolving
probability density function of the corresponding coarse-grained observables
Quantum interference structures in trapped ion dynamics beyond the Lamb-Dicke and rotating wave approximations
We apply wave packet methods to study an ion-trap system in the strong
excitation regime imposing neither the rotating wave nor the Lamb-Dicke
approximations. By this approach we show the existence of states with
restricted phase space evolution, as a genuine consequence of quantum
interference between wave packet fractions. A particular instance of such a
state oscillates between maximal entanglement and pure disentanglement between
the constitute subsystems. The characteristic crossover time is very rapid
making them suitable for state preparations of EPR or Schrodinger cat states.
Over longer time periods the dynamics of these states exhibits collapse-revival
patterns with well resolved fractional revivals in autocorrelation, inversion
and entanglement.Comment: 11 pages, 5 figures. Replaced with revised version. Phys. Rev. A 77,
053808 (2008
Coding Theorem for a Class of Quantum Channels with Long-Term Memory
In this paper we consider the transmission of classical information through a
class of quantum channels with long-term memory, which are given by convex
combinations of product channels. Hence, the memory of such channels is given
by a Markov chain which is aperiodic but not irreducible. We prove the coding
theorem and weak converse for this class of channels. The main techniques that
we employ, are a quantum version of Feinstein's Fundamental Lemma and a
generalization of Helstrom's Theorem.Comment: Some typos correcte
Precise Stellar Radial Velocities of an M Dwarf with a Michelson Interferometer and a Medium-resolution Near-infrared Spectrograph
Precise near-infrared radial velocimetry enables efficient detection and
transit verification of low-mass extrasolar planets orbiting M dwarf hosts,
which are faint for visible-wavelength radial velocity surveys. The TripleSpec
Exoplanet Discovery Instrument, or TEDI, is the combination of a variable-delay
Michelson interferometer and a medium-resolution (R=2700) near-infrared
spectrograph on the Palomar 200" Hale Telescope. We used TEDI to monitor GJ
699, a nearby mid-M dwarf, over 11 nights spread across 3 months. Analysis of
106 independent observations reveals a root-mean-square precision of less than
37 m/s for 5 minutes of integration time. This performance is within a factor
of 2 of our expected photon-limited precision. We further decompose the
residuals into a 33 m/s white noise component, and a 15 m/s systematic noise
component, which we identify as likely due to contamination by telluric
absorption lines. With further development this technique holds promise for
broad implementation on medium-resolution near-infrared spectrographs to search
for low-mass exoplanets orbiting M dwarfs, and to verify low-mass transit
candidates.Comment: 55 pages and 13 figures in aastex format. Accepted by PAS
Holonomy in the Schwarzschild-Droste Geometry
Parallel transport of vectors in curved spacetimes generally results in a
deficit angle between the directions of the initial and final vectors. We
examine such holonomy in the Schwarzschild-Droste geometry and find a number of
interesting features that are not widely known. For example, parallel transport
around circular orbits results in a quantized band structure of holonomy
invariance. We also examine radial holonomy and extend the analysis to spinors
and to the Reissner-Nordstr\"om metric, where we find qualitatively different
behavior for the extremal () case. Our calculations provide a toolbox
that will hopefully be useful in the investigation of quantum parallel
transport in Hilbert-fibered spacetimes.Comment: 18 Latex pages, 3 figures. Second replacement. This version as
published in CQG with some misprints correcte
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