The Experts below are selected from a list of 42003 Experts worldwide ranked by ideXlab platform
Ludo Max - One of the best experts on this subject based on the ideXlab platform.
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Spectral Coefficient analyses of word initial stop consonant productions suggest similar anticipatory coarticulation for stuttering and nonstuttering adults
Language and Speech, 2018Co-Authors: Santosh Maruthy, Yongqiang Feng, Ludo MaxAbstract:A longstanding hypothesis about the sensorimotor mechanisms underlying stuttering suggests that stuttered speech dysfluencies result from a lack of coarticulation. Formant-based measures of either the stuttered or fluent speech of children and adults who stutter have generally failed to obtain compelling evidence in support of the hypothesis that these individuals differ in the timing or degree of coarticulation. Here, we used a sensitive acoustic technique–Spectral Coefficient analyses–that allowed us to compare stuttering and nonstuttering speakers with regard to vowel-dependent anticipatory influences as early as the onset burst of a preceding voiceless stop consonant. Eight adults who stutter and eight matched adults who do not stutter produced C1VC2 words, and the first four Spectral Coefficients were calculated for one analysis window centered on the burst of C1 and two subsequent windows covering the beginning of the aspiration phase. Findings confirmed that the combined use of four Spectral coeffi...
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Spectral Coefficient analyses of word initial stop consonant productions suggest similar anticipatory coarticulation for stuttering and nonstuttering adults
Language and Speech, 2018Co-Authors: Santosh Maruthy, Yongqiang Feng, Ludo MaxAbstract:A longstanding hypothesis about the sensorimotor mechanisms underlying stuttering suggests that stuttered speech dysfluencies result from a lack of coarticulation. Formant-based measures of either ...
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detecting anticipatory effects in speech articulation by means of Spectral Coefficient analyses
Speech Communication, 2011Co-Authors: Yongqiang Feng, Grace Hao, Steve An Xue, Ludo MaxAbstract:Few acoustic studies have attempted to examine anticipatory effects in the earliest part of the release of stop consonants. We investigated the ability of Spectral Coefficients to reveal anticipatory coarticulation in the burst and early aspiration of stops in monosyllables. Twenty American English speakers produced stop (/k,t,p/) - vowel (/ae,i,o/) - stop (/k,t,p/) sequences in two phrase positions. The first four Spectral Coefficients (mean, standard deviation, skewness, kurtosis) were calculated for one window centered on the burst of the onset consonant and two subsequent, non-overlapping windows. All Coefficients showed an influence of vowel-to-consonant anticipatory coarticulation. Which onset consonant showed the strongest vowel effect depended on the specific Coefficient under consideration. A context-dependent consonant-to-consonant anticipatory effect was observed for onset /p/. Findings demonstrate that Spectral Coefficients can reveal subtle anticipatory adjustments as early as the burst of stop consonants. Different results for the four Coefficients suggest that comprehensive Spectral analyses offer advantages over other approaches. Studies using these techniques may expose previously unobserved articulatory adjustments among phonetic contexts or speaker populations.
Yongqiang Feng - One of the best experts on this subject based on the ideXlab platform.
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Spectral Coefficient analyses of word initial stop consonant productions suggest similar anticipatory coarticulation for stuttering and nonstuttering adults
Language and Speech, 2018Co-Authors: Santosh Maruthy, Yongqiang Feng, Ludo MaxAbstract:A longstanding hypothesis about the sensorimotor mechanisms underlying stuttering suggests that stuttered speech dysfluencies result from a lack of coarticulation. Formant-based measures of either the stuttered or fluent speech of children and adults who stutter have generally failed to obtain compelling evidence in support of the hypothesis that these individuals differ in the timing or degree of coarticulation. Here, we used a sensitive acoustic technique–Spectral Coefficient analyses–that allowed us to compare stuttering and nonstuttering speakers with regard to vowel-dependent anticipatory influences as early as the onset burst of a preceding voiceless stop consonant. Eight adults who stutter and eight matched adults who do not stutter produced C1VC2 words, and the first four Spectral Coefficients were calculated for one analysis window centered on the burst of C1 and two subsequent windows covering the beginning of the aspiration phase. Findings confirmed that the combined use of four Spectral coeffi...
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Spectral Coefficient analyses of word initial stop consonant productions suggest similar anticipatory coarticulation for stuttering and nonstuttering adults
Language and Speech, 2018Co-Authors: Santosh Maruthy, Yongqiang Feng, Ludo MaxAbstract:A longstanding hypothesis about the sensorimotor mechanisms underlying stuttering suggests that stuttered speech dysfluencies result from a lack of coarticulation. Formant-based measures of either ...
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detecting anticipatory effects in speech articulation by means of Spectral Coefficient analyses
Speech Communication, 2011Co-Authors: Yongqiang Feng, Grace Hao, Steve An Xue, Ludo MaxAbstract:Few acoustic studies have attempted to examine anticipatory effects in the earliest part of the release of stop consonants. We investigated the ability of Spectral Coefficients to reveal anticipatory coarticulation in the burst and early aspiration of stops in monosyllables. Twenty American English speakers produced stop (/k,t,p/) - vowel (/ae,i,o/) - stop (/k,t,p/) sequences in two phrase positions. The first four Spectral Coefficients (mean, standard deviation, skewness, kurtosis) were calculated for one window centered on the burst of the onset consonant and two subsequent, non-overlapping windows. All Coefficients showed an influence of vowel-to-consonant anticipatory coarticulation. Which onset consonant showed the strongest vowel effect depended on the specific Coefficient under consideration. A context-dependent consonant-to-consonant anticipatory effect was observed for onset /p/. Findings demonstrate that Spectral Coefficients can reveal subtle anticipatory adjustments as early as the burst of stop consonants. Different results for the four Coefficients suggest that comprehensive Spectral analyses offer advantages over other approaches. Studies using these techniques may expose previously unobserved articulatory adjustments among phonetic contexts or speaker populations.
Santosh Maruthy - One of the best experts on this subject based on the ideXlab platform.
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Spectral Coefficient analyses of word initial stop consonant productions suggest similar anticipatory coarticulation for stuttering and nonstuttering adults
Language and Speech, 2018Co-Authors: Santosh Maruthy, Yongqiang Feng, Ludo MaxAbstract:A longstanding hypothesis about the sensorimotor mechanisms underlying stuttering suggests that stuttered speech dysfluencies result from a lack of coarticulation. Formant-based measures of either the stuttered or fluent speech of children and adults who stutter have generally failed to obtain compelling evidence in support of the hypothesis that these individuals differ in the timing or degree of coarticulation. Here, we used a sensitive acoustic technique–Spectral Coefficient analyses–that allowed us to compare stuttering and nonstuttering speakers with regard to vowel-dependent anticipatory influences as early as the onset burst of a preceding voiceless stop consonant. Eight adults who stutter and eight matched adults who do not stutter produced C1VC2 words, and the first four Spectral Coefficients were calculated for one analysis window centered on the burst of C1 and two subsequent windows covering the beginning of the aspiration phase. Findings confirmed that the combined use of four Spectral coeffi...
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Spectral Coefficient analyses of word initial stop consonant productions suggest similar anticipatory coarticulation for stuttering and nonstuttering adults
Language and Speech, 2018Co-Authors: Santosh Maruthy, Yongqiang Feng, Ludo MaxAbstract:A longstanding hypothesis about the sensorimotor mechanisms underlying stuttering suggests that stuttered speech dysfluencies result from a lack of coarticulation. Formant-based measures of either ...
Paul A. Hwang - One of the best experts on this subject based on the ideXlab platform.
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Surface wave Spectral properties of centimeter to decameter wavelengths: variable Spectral slope and non-equilibrium spectrum
Ocean Dynamics, 2020Co-Authors: Paul A. HwangAbstract:Understanding the wave properties in centimeter to decameter (cmDm) wavelength range is of great interest to ocean remote sensing and air-sea interaction. For more than six decades, cmDm waves are generally considered to be in the equilibrium range, and its Spectral function has a constant slope: − 5 or − 4 in the 1D frequency spectrum and − 3 or − 2.5 in the 1D wavenumber spectrum. Some variations of the equilibrium spectrum model include varying the frequency Spectral slope from − 4 to − 5 at some multiple of the Spectral peak frequency, or incorporating a threshold velocity in the reference wind speed. Extensive efforts are then devoted to quantifying the Spectral Coefficient of the equilibrium spectrum function. This paper emphasizes that the observed wave Spectral slope in the ocean is mostly non-constant. Therefore, the wave properties in field observations are significantly different from those inferred from assuming a constant Spectral slope. The variable Spectral slope is indicative of a non-equilibrium nature of ocean surface waves. Furthermore, from signal-to-noise consideration, surface slope is much more suited than elevation for evaluating the Spectral slope and for quantifying the cmDm wave properties. Microwave sensors are excellent instruments for providing the ocean surface slope measurements. Several large datasets of lowpass-filtered mean square slope (LPMSS) have been reported recently. Combining the LPMSS observations with a spectrum function that accommodates a variable Spectral slope, several quantitative results on the variable Spectral slope and cmDm wave properties are presented.
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Variable Spectral Slope and Nonequilibrium Surface Wave Spectrum
arXiv: Atmospheric and Oceanic Physics, 2019Co-Authors: Paul A. HwangAbstract:The wave Spectral properties in the centimeter to decameter (cmDm) wavelength range is of great interest to ocean remote sensing and studies of ocean surface processes including the surface roughness, air-sea energy and momentum exchanges, wave breaking, and whitecap coverage. For more than six decades, the cmDm wave components are generally considered to be in the equilibrium range, and its Spectral function has a constant slope: -5 or -4 in the 1D frequency spectrum, and -3 or -2.5 in the 1D wavenumber spectrum. Some variations of the equilibrium spectrum models include varying the frequency Spectral slope from 4 to 5 at some multiple of the Spectral peak frequency, or incorporating a threshold velocity in the reference wind speed. Extensive efforts are then devoted to quantifying the Spectral Coefficient of the equilibrium spectrum function. The observed wind wave Spectral slopes in the ocean environment, however, are rarely constant. The variable Spectral slope is indicative of the nonequilibrium nature of surface wind waves in the field. As a result the wave properties in field observations are significantly different from those inferred from assuming a constant Spectral slope. From signal-to-noise consideration the surface slope measurements are much more sensitive than the elevation data for the study of cmDm waves. Recently, several large datasets of low-pass-filtered mean square slope (LPMSS) have been reported in support of the Global Navigation Satellite System Reflectometry (GNSSR) tropical cyclone wind sensing effort. Combining the LPMSS observations with a spectrum model that accommodates a variable Spectral slope, this paper seeks to quantify the connection between the variable Spectral slope and the Spectral properties of cmDm waves.
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Airborne Measurements of the Wavenumber Spectra of Ocean Surface Waves. Part I: Spectral Slope and Dimensionless Spectral Coefficient*
Journal of Physical Oceanography, 2000Co-Authors: Paul A. Hwang, David W. Wang, Edward J. Walsh, William B. Krabill, Robert N. SwiftAbstract:An airborne scanning lidar system acquires 3D spatial topography of ocean surface waves. From the spatial data, wavenumber spectra are computed directly. The Spectral analyses of two distinctively different wave fields are presented. The first one is a quasi-steady wave field under active wind generation, and the second one is a decaying wave field following a slackening of the wind field. Subtle differences in different representations of the one-dimensional spectrum (omnidirectional, marginal, and traverse) are illustrated. The Spectral properties in terms of the dimensionless Spectral Coefficient and Spectral slope in the equilibrium range are investigated using the wavenumber spectra directly computed from the 3D topography of the ocean surface. The results are in excellent agreement with existing data. The rapid data acquisition afforded by an airborne system provides an enhanced capability for studying the spatial variation of a wave field with minimal temporal changes in the environmental forcing conditions. The data of the 3D surface topography are also ideal for the quantitative investigation of the directional properties of a random wave field.
Kenneth Rose - One of the best experts on this subject based on the ideXlab platform.
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a unified framework for Spectral domain prediction and end to end distortion estimation in scalable video coding
International Conference on Image Processing, 2011Co-Authors: Jingning Han, Vinay Melkote, Kenneth RoseAbstract:A novel scalable coding approach is proposed for video transmission over lossy networks, which builds on two estimation-theoretic (ET) paradigms previously developed by our group: (1) an ET approach to enhancement layer prediction in scalable video coding (ET-SVC) that optimally combines all available information from both the current base layer and prior enhancement layer frames, and (2) the Spectral Coefficient-wise optimal recursive estimate (SCORE) of end-to-end distortion. SCORE provides the encoder with an estimate of distortion per decoder-reconstructed transform Coefficient, accounting for the effects of quantization, concealment, packet loss and error propagation via the prediction loop. The current work significantly extends the scope of SCORE to encompass the setting of ET-SVC, whose prediction involves non-linear operations. This advance enables optimization of ET-SVC systems for transmission over lossy networks, thereby combining optimal prediction with optimal mode decisions at the enhancement layer. Experiments first demonstrate the estimation accuracy of SCORE in the settings of the ET-SVC coder. They then show considerable gains when SCORE is incorporated into ET-SVC to optimize encoding decisions under a wide range of packet loss and bit rates.
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a Spectral approach to recursive end to end distortion estimation for sub pixel motion compensated video coding
International Conference on Acoustics Speech and Signal Processing, 2011Co-Authors: Jingning Han, Vinay Melkote, Kenneth RoseAbstract:Error resilient video coding critically relies on the accuracy of end-to-end distortion estimation. An established solution, the recursive optimal per-pixel estimate (ROPE), is based on tracking the first and second moments of the decoder reconstructed pixels. This paper is focused on an alternative estimation approach, the Spectral Coefficient-wise optimal recursive estimate (SCORE), whose recursion is performed in the transform domain. The SCORE formulation is extended to derive a new technique for effective end-to-end distortion estimation, which accounts for sub-pixel motion compensation. Specifically, this technique exploits properties of the transform, such as Coefficient de-correlation and energy compaction, to overcome ROPE's remaining shortcoming due to the proliferation of cross-correlation terms requiring excessive complexity or relatively crude approximations. Experiments show that the accuracy of SCORE matches ROPE in the full-pixel motion compensation setting, where ROPE is known to be optimal. More importantly, in the problematic setting of sub-pixel motion compensation, SCORE substantially outperforms ROPE and yields highly accurate distortion estimation.
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a recursive optimal Spectral estimate of end to end distortion in video communications
2010 18th International Packet Video Workshop, 2010Co-Authors: Jingning Han, Vinay Melkote, Kenneth RoseAbstract:End-to-end distortion estimation is critical to effective error-resilient video coding. The recursive optimal per-pixel estimate (ROPE) is a known approach to compute up to second moments of decoder-reconstructed pixels, and thereby optimally estimate the distortion. ROPE accurately accounts for encoding/decoding operations that are recursive in the pixel domain, and their interaction with packet loss and decoder concealment. The premise of this work is that considerable gains could be recouped by a dual estimation technique that would perform its recursion in the transform domain. This opens the door to accurate distortion estimation in conjunction with estimation-theoretic source coding approaches that involve transform domain operations, including improved prediction in both single-layer and scalable video coding. We present a novel recursive optimal estimate that operates entirely in the transform domain, namely, the Spectral Coefficient-wise optimal recursive estimate (SCORE). The method overcomes intricacies due to motion compensation from “off-grid” blocks. We first demonstrate that its accuracy matches ROPE in the usual setting where ROPE is known to be optimal. Then we consider an enhanced encoding scenario involving Spectral operations that cannot be accurately tracked by ROPE, but for which SCORE still maintains optimality and hence enables substantial end-to-end performance gains over a large range of packet loss rates.