14,933 research outputs found
Iron-Catalyzed, Highly Regioselective Synthesis of alpha-Aryl Carboxylic Acids from Styrene Derivatives and CO2
Glottal-synchronous speech processing
Glottal-synchronous speech processing is a field of speech science where the pseudoperiodicity
of voiced speech is exploited. Traditionally, speech processing involves segmenting
and processing short speech frames of predefined length; this may fail to exploit the inherent
periodic structure of voiced speech which glottal-synchronous speech frames have
the potential to harness. Glottal-synchronous frames are often derived from the glottal
closure instants (GCIs) and glottal opening instants (GOIs).
The SIGMA algorithm was developed for the detection of GCIs and GOIs from
the Electroglottograph signal with a measured accuracy of up to 99.59%. For GCI and
GOI detection from speech signals, the YAGA algorithm provides a measured accuracy
of up to 99.84%. Multichannel speech-based approaches are shown to be more robust to
reverberation than single-channel algorithms.
The GCIs are applied to real-world applications including speech dereverberation,
where SNR is improved by up to 5 dB, and to prosodic manipulation where the importance
of voicing detection in glottal-synchronous algorithms is demonstrated by subjective
testing. The GCIs are further exploited in a new area of data-driven speech modelling,
providing new insights into speech production and a set of tools to aid deployment into
real-world applications. The technique is shown to be applicable in areas of speech coding,
identification and artificial bandwidth extension of telephone speec
High-order, Dispersionless "Fast-Hybrid" Wave Equation Solver. Part I: Sampling Cost via Incident-Field Windowing and Recentering
This paper proposes a frequency/time hybrid integral-equation method for the
time dependent wave equation in two and three-dimensional spatial domains.
Relying on Fourier Transformation in time, the method utilizes a fixed
(time-independent) number of frequency-domain integral-equation solutions to
evaluate, with superalgebraically-small errors, time domain solutions for
arbitrarily long times. The approach relies on two main elements, namely, 1) A
smooth time-windowing methodology that enables accurate band-limited
representations for arbitrarily-long time signals, and 2) A novel Fourier
transform approach which, in a time-parallel manner and without causing
spurious periodicity effects, delivers numerically dispersionless
spectrally-accurate solutions. A similar hybrid technique can be obtained on
the basis of Laplace transforms instead of Fourier transforms, but we do not
consider the Laplace-based method in the present contribution. The algorithm
can handle dispersive media, it can tackle complex physical structures, it
enables parallelization in time in a straightforward manner, and it allows for
time leaping---that is, solution sampling at any given time at
-bounded sampling cost, for arbitrarily large values of ,
and without requirement of evaluation of the solution at intermediate times.
The proposed frequency-time hybridization strategy, which generalizes to any
linear partial differential equation in the time domain for which
frequency-domain solutions can be obtained (including e.g. the time-domain
Maxwell equations), and which is applicable in a wide range of scientific and
engineering contexts, provides significant advantages over other available
alternatives such as volumetric discretization, time-domain integral equations,
and convolution-quadrature approaches.Comment: 33 pages, 8 figures, revised and extended manuscript (and now
including direct comparisons to existing CQ and TDIE solver implementations)
(Part I of II
Mitigation of artifacts due to isolated acoustic heterogeneities in photoacoustic computed tomography using a variable data truncation-based reconstruction method
Photoacoustic computed tomography (PACT) is an emerging computed imaging
modality that exploits optical contrast and ultrasonic detection principles to
form images of the absorbed optical energy density within tissue. If the object
possesses spatially variant acoustic properties that are unaccounted for by the
reconstruction method, the estimated image can contain distortions. While
reconstruction methods have recently been developed to compensate for this
effect, they generally require the object's acoustic properties to be known a
priori. To circumvent the need for detailed information regarding an object's
acoustic properties, we previously proposed a half-time reconstruction method
for PACT. A half-time reconstruction method estimates the PACT image from a
data set that has been temporally truncated to exclude the data components that
have been strongly aberrated. However, this method can be improved upon when
the approximate sizes and locations of isolated heterogeneous structures, such
as bones or gas pockets, are known. To address this, we investigate PACT
reconstruction methods that are based on a variable data truncation (VDT)
approach. The VDT approach represents a generalization of the half-time
approach, in which the degree of temporal truncation for each measurement is
determined by the distance between the corresponding ultrasonic transducer
location and the nearest known bone or gas void location. Computer-simulated
and experimental data are employed to demonstrate the effectiveness of the
approach in mitigating artifacts due to acoustic heterogeneities
Austerity, Competitiveness and Neoliberalism Redux: Ontario Responds to the Great Recession
This article examines the deepening integration of market imperatives throughout the province of Ontario. We do this by, first, examining neoliberalism’s theoretical underpinnings, second, reviewing Ontario’s historical context, and third, scrutinizing the Open Ontario Plan, with a focus on proposed changes to employment standards legislation. We argue that contrary to claims of shared restraint and the pressing need for public austerity, Premier McGuinty’s Liberal’s have re-branded and re-packaged core neoliberal policies in such a manner that costs are socialized and profits privatized, thereby intensifying class polarization along with its racialized and gendered diversities.
Cet article analyse l’intégration de plus en plus profonde des impératifs du marché dans la province de l’Ontario. Nous faisons cette analyse, premièrement, en analysant les bases théoriques du néolibéralisme, deuxièmement, en décrivant le contexte historique de l’Ontario, et troisièmement, en examinant le “Open Ontario Plan”, sous l’angle particulier des propositions de changement de la législation sur le droit du travail. Nous soutenons que sous le couvert de discours prônant le partage de l’austérité et l’impérieuse nécessité de restreindre les dépenses publiques, les Libéraux du Premier McGuinty ont ré-étiqueté et reformulé les politiques néolibérales de façon que les coûts soient socialisés et les profits privatisés, aggravant ainsi la polarisation des classes ainsi que les inégalités liées à la race et au genre
A PRODUCER-LEVEL CROSS-HEDGE FOR ROUGH RICE USING WHEAT FUTURES
This study explores the potential of routine preharvest cross-hedging of rough rice using wheat futures contract prices. A numerical simulation approach combined with risk efficiency analysis evaluates a wide rage of cross-hedging alternatives. Results establish that farm-level cross-hedging can be considered a viable marketing alternative.Marketing,
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