18,043 research outputs found
A Multi-Phase Anglo-Saxon Site in Ewelme
New evidence is presented for a middle Anglo-Saxon ‘productive’ site on hilly ground north-west of Ewelme in south Oxfordshire. Coins and other finds from metal-detecting activity suggest the existence of an eighth- to ninth-century meeting or trading point located close to the Icknield Way. Th is place takes on an added significance because of its proximity to an early Anglo-Saxon cemetery and probably a late Anglo-Saxon meeting place. Th e authors provide an initial assessment of the site, its likely chronological development and its relationship with wider Anglo-Saxon activity in the upper Thames region and beyond. Some suggestions are made about the implications of the existence of such a long-lasting or recurring centre of activity for early medieval inhabitants’ perceptions of landscape
A Denotational Semantics for SPARC TSO
The SPARC TSO weak memory model is defined axiomatically, with a
non-compositional formulation that makes modular reasoning about programs
difficult. Our denotational approach uses pomsets to provide a compositional
semantics capturing exactly the behaviours permitted by SPARC TSO. It uses
buffered states and an inductive definition of execution to assign an
input-output meaning to pomsets. We show that our denotational account is sound
and complete relative to the axiomatic account, that is, that it captures
exactly the behaviours permitted by the axiomatic account. Our compositional
approach facilitates the study of SPARC TSO and supports modular analysis of
program behaviour
Speech Enhancement Using An {MMSE} Spectral Amplitude Estimator Based On A Modulation Domain Kalman Filter With A Gamma Prior
In this paper, we propose a minimum mean square error spectral estimator for clean speech spectral amplitudes that uses a Kalman filter to model the temporal dynamics of the spectral amplitudes in the modulation domain. Using a two-parameter Gamma distribution to model the prior distribution of the speech spectral amplitudes, we derive closed form expressions for the posterior mean and variance of the spectral amplitudes as well as for the associated update step of the Kalman filter. The performance of the proposed algorithm is evaluated on the TIMIT core test set using the perceptual evaluation of speech quality (PESQ) measure and segmental SNR measure and is shown to give a consistent improvement over a wide range of SNRs when compared to competitive algorithms
A Weighted STOI Intelligibility Metric Based On Mutual Information
It is known that the information required for the intelligibility of a speech signal is distributed non-uniformly in time. In this paper we propose WSTOI, a modified version of STOI, a speech intelligibility metric. With WSTOI the contribution of each time-frequency cell is weighted by an estimate of its intelligibility content. This estimate is equal to the mutual information between two hypothetical signals at either end of a simplified model of human communication. Listening tests show that the modification improves the prediction accuracy of STOI at all performance levels on both long and short utterances. An improvement was observed across all tested noise types and suppression algorithms
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