5,003 research outputs found
Effects of noise suppression and envelope dynamic range compression on the intelligibility of vocoded sentences for a tonal language
Vocoder simulation studies have suggested that the carrier signal type employed affects the intelligibility of vocoded speech. The present work further assessed how carrier signal type interacts with additional signal processing, namely, single-channel noise suppression and envelope dynamic range compression, in determining the intelligibility of vocoder simulations. In Experiment 1, Mandarin sentences that had been corrupted by speech spectrum-shaped noise (SSN) or two-talker babble (2TB) were processed by one of four single-channel noise-suppression algorithms before undergoing tone-vocoded (TV) or noise-vocoded (NV) processing. In Experiment 2, dynamic ranges of multiband envelope waveforms were compressed by scaling of the mean-removed envelope waveforms with a compression factor before undergoing TV or NV processing. TV Mandarin sentences yielded higher intelligibility scores with normal-hearing (NH) listeners than did noise-vocoded sentences. The intelligibility advantage of noise-suppressed vocoded speech depended on the masker type (SSN vs 2TB). NV speech was more negatively influenced by envelope dynamic range compression than was TV speech. These findings suggest that an interactional effect exists between the carrier signal type employed in the vocoding process and envelope distortion caused by signal processing
A nonlinear Schr\"odinger equation for water waves on finite depth with constant vorticity
A nonlinear Schr\"odinger equation for the envelope of two dimensional
surface water waves on finite depth with non zero constant vorticity is
derived, and the influence of this constant vorticity on the well known
stability properties of weakly nonlinear wave packets is studied. It is
demonstrated that vorticity modifies significantly the modulational instability
properties of weakly nonlinear plane waves, namely the growth rate and
bandwidth. At third order we have shown the importance of the coupling between
the mean flow induced by the modulation and the vorticity. Furthermore, it is
shown that these plane wave solutions may be linearly stable to modulational
instability for an opposite shear current independently of the dimensionless
parameter kh, where k and h are the carrier wavenumber and depth respectively
An aquarium for Boston
Thesis (M.Arch)--Massachusetts Institute of Technology, Dept. of Architecture, 1960.Accompanying drawings held by MIT Museum.Includes bibliographical references.by Donald S. C. Tsao.M.Arc
The application of ultrasonic NDT techniques in tribology
The use of ultrasonic reflection is emerging as a technique for studying tribological contacts. Ultrasonic waves can be transmitted non-destructively through machine components and their behaviour at an interface describes the characteristics of that contact. This paper is a review of the current state of understanding of the mechanisms of ultrasonic reflection at interfaces, and how this has been used to investigate the processes of dry rough surface contact and lubricated contact. The review extends to cover how ultrasound has been used to study the tribological function of certain engineering machine elements
Cross-reactive neutralizing antibody response to enterovirus 71 infection in Taiwanese young children
Heme Oxygenase-1 Expression Affects Murine Abdominal Aortic Aneurysm Progression.
Heme oxygenase-1 (HO-1), the rate-limiting enzyme in heme degradation, is a cytoprotective enzyme upregulated in the vasculature by increased flow and inflammatory stimuli. Human genetic data suggest that a diminished HO-1 expression may predispose one to abdominal aortic aneurysm (AAA) development. In addition, heme is known to strongly induce HO-1 expression. Utilizing the porcine pancreatic elastase (PPE) model of AAA induction in HO-1 heterozygous (HO-1+/-, HO-1 Het) mice, we found that a deficiency in HO-1 leads to augmented AAA development. Peritoneal macrophages from HO-1+/- mice showed increased gene expression of pro-inflammatory cytokines, including MCP-1, TNF-alpha, IL-1-beta, and IL-6, but decreased expression of anti-inflammatory cytokines IL-10 and TGF-beta. Furthermore, treatment with heme returned AAA progression in HO-1 Het mice to a wild-type profile. Using a second murine AAA model (Ang II-ApoE-/-), we showed that low doses of the HMG-CoA reductase inhibitor rosuvastatin can induce HO-1 expression in aortic tissue and suppress AAA progression in the absence of lipid lowering. Our results support those studies that suggest that pleiotropic statin effects might be beneficial in AAA, possibly through the upregulation of HO-1. Specific targeted therapies designed to induce HO-1 could become an adjunctive therapeutic strategy for the prevention of AAA disease
Present status and future prospects for a Higgs boson discovery at the Tevatron and LHC
Discovering the Higgs boson is one of the primary goals of both the Tevatron
and the Large Hadron Collider (LHC). The present status of the Higgs search is
reviewed and future prospects for discovery at the Tevatron and LHC are
considered. This talk focuses primarily on the Higgs boson of the Standard
Model and its minimal supersymmetric extension. Theoretical expectations for
the Higgs boson and its phenomenological consequences are reviewed.Comment: 13 pages, 9 figures, 2 tables, jpconf documentclass file, invited
talk at PASCOS 2010, the 16th International Symposium on Particles, Strings
and Cosmology, Valencia, Spain, 19--23 July 201
Chronic stent-induced injury and inflammation results in sustained activation of the cell cycle in the porcine model
Energetics and atomic mechanisms of dislocation nucleation in strained epitaxial layers
We study numerically the energetics and atomic mechanisms of misfit
dislocation nucleation and stress relaxation in a two-dimensional atomistic
model of strained epitaxial layers on a substrate with lattice misfit.
Relaxation processes from coherent to incoherent states for different
transition paths are studied using interatomic potentials of Lennard-Jones type
and a systematic saddle point and transition path search method. The method is
based on a combination of repulsive potential minimization and the Nudged
Elastic Band method. For a final state with a single misfit dislocation, the
minimum energy path and the corresponding activation barrier are obtained for
different misfits and interatomic potentials. We find that the energy barrier
decreases strongly with misfit. In contrast to continuous elastic theory, a
strong tensile-compressive asymmetry is observed. This asymmetry can be
understood as manifestation of asymmetry between repulsive and attractive
branches of pair potential and it is found to depend sensitively on the form of
the potential.Comment: 11 pages, 9 figures, to appear in Phys. Rev.
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