bluuebunny/crossref_metadata_2025 huggingface dataset:
Articulation from acoustics: Estimating constriction degree from the acoustic signal.
Authors: Parrell Benjamin
Published: October 2010

Voiced stops in Spanish (/b/, /d/, /g/) are often realized as approximants with incomplete supralaryngeal closure. A number of studies have shown that these are not allophonic variants but rather form part of a continuum of productions, influenced by a number of segmental and prosodic factors. Most work on this topic has used indirect acoustic measurements to estimate articulatory constriction degree. These methods include energy difference in CV (intensity minimum of the consonant over intensity maximum of adjacent vowels), spectral tilt, and maximum rising velocity of the intensity envelope in the CV transition [Kingston, LASP 3, (2008)]. These acoustic measures of constriction, while generally showing the same overall patterns, at times show significant differences in exact results [Hualde et al., LSRL (2010)]. The current study tests the accuracy of all three measures by comparing the acoustic results with articulatorily constriction degree, measured via electromagnetic articulometry (EMA). Comparisons are conducted using only /b/, as calculation of articulatory constriction degree using EMA is more accurate for bilabials than for coronals or velars. The results show for the first time the relative accuracy of three widely used acoustic tools for estimating articulatory constriction degree.
Exploring a canonical correlation analysis technique for the study of articulatory coordination.
Authors: Lee Sungbok , Byrd Dani
Published: October 2010

Canonical correlation analysis provides an effective way to visualize the patterns of association or inter-relations between two sets of variables. When observations or measurements are curves such as time series or serial data in general, a canonical correlation analysis technique provided by the functional data analysis (FDA) methodology [Ramsay and Silverman (2005)] is an ideal choice. Although the FDA canonical correlation analysis has a potential usefulness in the study of articulatory coordination, it has been rarely utilized for that purpose. In this study, the FDA canonical correlation analysis technique is applied to midsagittal vocal tract contour data produced in four different emotions (neutral, anger, happiness, and sadness) obtained by a real-time magnetic resonance imaging technique. The purpose is to examine overall differences in the coordination of x and y components of vocal tract contours as a function of emotion. Results indicate that differences in the variance-covariance matrices of x and y components as well as differences in the first three canonical variates among the four emotions are clearly observable, which indicates different weighting patterns of x and y components along the vocal tract for emotional contrast. Those results and other possible applications of the technique will be discussed. [Work supported by NIH.]
Anticipatory and carry-over laryngeal coarticulation in 5-year-old children and adults.
Authors: Koenig Laura L.
Published: October 2010

Many studies have compared the time course of coarticulation between children and adults. Most of this work has assessed supralaryngeal aspects of articulation. However, laryngeal coarticulation also occurs, as evident in measures of fundamental frequency (f0) and voice source features in vowels flanking voiceless consonants. Moreover, most developmental work has focused on anticipatory coarticulation, which is thought to reflect planning. In contrast, carryover coarticulation is thought to result mainly from articulatory inertia. Thus, the two forms of coarticulation may show different developmental time courses. This work evaluates laryngeal coarticulation in typically developing 5-year-old English-speaking children and adult females via measures of oral airflow. Speakers produced approximately 25 repetitions each of intervocalic /b p h/, with the target consonant initiating a stressed syllable. From the airflow signal, pulse-by-pulse measures were made of the smoothed airflow (DC flow), the pulse amplitude (AC flow), and f0 before and after the target consonants. Previous analyzes of a subset of these data indicated that carryover coarticulation in children was highly variable from token to token, complicating age comparisons based on average measures. Of particular interest here is whether the degree of coarticulatory variability differs depending on direction (anticipatory versus carryover).
Evidence of laryngeal blocks in acoustic analysis of stuttered speech.
Authors: Menezes Caroline , Dowler Chelsea , Ellis Lee
Published: October 2010

Stuttered speech is characterized by the presence of speech blocks. Little is known on what causes blocks. These blocks typically occur on onset segments of a syllable regardless of the number of syllables in the stuttered word. Blocks on voiced and voiceless stops often result in part word repetitions (e.g., c c c car), while fricatives and other + continuant sounds will be prolonged. Therefore, the manner of sound production plays a role in identifying the types of blocks that will occur. Preliminary acoustic analysis of the speech of one subject with severe stuttering reveals that blocks occurring on voiced +continuant segments are prolonged; however, there is partial or complete devoicing of the voiced segment associated with the block. Devoicing is evident in the spectrogram by the absence of voicing bar and fundamental frequency. Sonorant segments can be identified by their resonant frequencies. This pattern was found in both spontaneous and read speech. The presence of resonant frequencies in the absence of a fundamental frequency indicates a block at the region of the vocal folds. A follow up to this study analyzing simultaneous EGG and acoustic recordings to look at the glottal cycle during stuttered blocks is required.
Acoustic frame selection for acoustic-to-articulatory inversion.
Authors: Ghosh Prasanta , Narayanan Shrikanth
Published: October 2010

The estimation of the trajectories of articulator movements from a given acoustic speech signal is known as the acoustic-to-articulatory inversion. In this work, it is shown that all acoustic frames are not equally important while performing the acoustic-to-articulatory inversion. A frame selection strategy is proposed, where the weight of each acoustic frame is determined for the articulatory inversion task. These weights are finally used in an optimization framework using a generalized smoothness criterion to estimate the articulator movement. We find that the accuracy of the estimates of articulator trajectories improves in terms of both average rms error and correlation with the measured reference trajectories using the proposed frame selection strategy.
Automatic detection and comparison of vowel nasalization in American English.
Authors: Yuan Jiahong , Seidl Amanda , Cristiá Alejandrina
Published: October 2010

This study investigated the use of MFCC and SVM for automatic detection and comparison of vowel nasalization. The standard 39 MFCC coefficients were extracted at the center of the vowel, and an SVM classifier was built to discriminate between oral and nasalized vowels in a vowel-independent manner. When trained on the TIMIT training set and tested on its test set, the method achieved 88.3% overall accuracy in nasalization detection, 88.5% on nasalized vowels (i.e., preceding a nasal consonant), and 88.2% on oral vowels (i.e., not in the context of nasal consonants). The method was also applied to a database of 2606 oral and nasalized vowels of /ae/ and /E/ in a systematically designed and collected corpus of adult- and infant-directed speech (80% for training and 20% for test); an overall accuracy of 88.5% was obtained. It was observed that the accuracy for /ae/ (94.2%) was greatly higher than that for /E/ (82.9%). The Euclidian distance calculated on the 39 MFCC coefficients between the oral and nasalized /ae/ was also much larger than the distance between the oral and nasalized /E/. These results reflect the fact that the degree of nasalization depends on vowel identity.
Scattering of evanescent pipe modes form elastic spherical objects external to a fluid-filled, submerged cylindrical waveguide.
Authors: Bingham Jill P. , Calvo David C.
Published: October 2010

Investigation into the interaction of low-frequency fluid-borne, radially decaying pipe modes with elastic objects exterior to a cylindrical waveguide using the elastodynamic finite integration technique (EFIT). The system is an oil-filled steel pipe submerged in water. When the sound speed of the conveyed fluid is lower than the exterior fluid, there exist fluid/fluid modes possessing cutoff frequencies supported by both the interior and exterior fluids. These are in addition to the higher-velocity, steel-borne modes, and the low-velocity internal-fluid-borne mode without a cutoff frequency. Excitation of a fluid/fluid mode near its cutoff frequency results in its further penetration into the exterior fluid. An object close to the pipe wall allows for scattering of this evanescent mode. An advantage of EFIT, direct manipulation of material properties, allows for easy inclusion of objects. Simulation results show the scattering from elastic objects with and without air pockets that are compared to analytical plane wave solutions. A plastic sphere with a radius ¾ the pipe inner radius gives a backscattered signal 15 dB below and a forward scattering signal 10 dB below the incident field. In order to achieve mode separation over shorter propagation distances, the analytical mode solution is used for single mode excitation.
Scattering from extended targets in a range-dependent fluctuating ocean waveguide from theory and experiments where the sonar equation is invalid.
Authors: Jagannathan Srinivasan , Küsel Elizabeth T. , Ratilal Purnima , Makris Nicholas C.
Published: October 2010

Bi-static, long-range measurements of acoustic scattered returns from vertically extended, air-filled cylindrical targets were made during three separate ONR-sponsored field experiments in fluctuating continental shelf environments. We show that the sonar equation estimates of mean scattered intensity from these targets lead to large errors, differing by an order of magnitude from both our measurements and waveguide scattering theory. This is because the sonar equation approximation is not applicable to targets large compared to the acoustic wavelength in an ocean waveguide. We find that use of the Ingenito scattering model also leads to significant errors in estimating mean target scattered intensity in our field experiments because they were conducted in range-dependent ocean environments with large variations in sound speed structure over the depth of the targets, scenarios that violate the basic assumptions of the Ingenito model. Here we describe scattering from extended cylindrical targets in a range-dependent fluctuating ocean waveguide using a Green’s theorem based full-field model that takes into account nonuniform sound speed structure over the target’s depth extent. We show that this model accurately describes the statistics of the acoustic field scattered by the targets in all three field experiments.
Development and use of an acoustic device to estimate size distribution of catfish in commercial ponds.
Authors: Heffington John D. , Chambers James P. , Goodwiller Bradley T. , Beecham Rachel V. , Heikes David
Published: October 2010

With increasing seafood demand, aquaculture remains a major industry in the United States. Channel catfish pond management strategies are compromised by high fish densities with large size distributions that result from years of continuous culture without a total harvest. Recent work has been presented on the Aquascanner SONAR system, which evaluates the total population of a pond but is less effective in determining the size distribution. One method to provide the size distribution is to pull a sub sample seine net across a pond to obtain a sample of the fish and manually weigh them in a time-consuming process. The work presented here attempts to use acoustic backscatter to determine the size distribution of the fish in lieu of the manual weight measurements. After being collected by the sub sample net, the fish are allowed to swim back into the pond through a restrictive pipe and are pinged acoustically to determine their target strength and thus size. The design of the system, size estimation method and results from several pond studies will be discussed. [Work supported by the USDA, SRAC.]
Acoustic measurements of clays and silts.
Authors: Carpenter Wayne O. , Wren Daniel G. , Kuhnle Roger A. , Diers Jeffrey A. , Chambers James P.
Published: October 2010

Measuring the concentration of particles smaller than 100 μm in water has implications for river engineering, reservoir management, and environmental stewardship. The use of a single frequency system to measure these fine particles is attractive, since it avoids the complication and cost of multi-frequency electronics. Using two 20-MHz immersion transducers, attenuation and backscatter measurements were obtained for acoustic signals propagated through mixtures of clay (bentonite, illite, and kaolinite) and silt particles suspended in water. The resulting data set has allowed for relationships between backscatter and attenuation to be used for estimating both the concentration and clay/silt ratio in water. Detailed experimental results based on data collected in a test-tank at the National Center for Physical Acoustics will be presented, including estimates of measurement error across a broad range of concentrations (0.01–14 g/l) and particle sizes (0.1–64-μm-diameter particles).
Variability of parameter estimates used in the Buckingham viscous grain shearing model.
Authors: Richardson Michael , Sanders William
Published: October 2010

A compilation of 54 sets of geoacoustic measurements of marine sediments was reviewed in order to bound estimates of parameters for use in Buckingham’s grain shearing (GS) theory of acoustic propagation. These data, for unconsolidated sands (siliciclastic and carbonate) with grain sizes between 0.0156 and 0.57 mm, were all made in shallow water (maximum depth of 60 m) sites at diverse locales. In each data set, measurements of the speed and attenuation of the compressional wave at high frequency, the shear wave speed at 1 kHz, porosity, and bulk density are sufficient to calculate the three free parameters in GS theory (a material exponent, a compressional coefficient, and a shear coefficient). The spread of the values calculated for GS parameters, combined with a sensitivity analysis, does not support the use of a single material exponent value for all sediments. Shear wave attenuation measured at 18 sites was compared to the predictions of Buckingham’s (2010) most recent version of the VGS model. In this model the shear viscoelastic time constant is based on the wavelength of the propagating shear wave rather than shear speed.
Computer analysis of speech intelligibility in classrooms.
Authors: Feijoo Sergio
Published: October 2010

The objective of this research is to study the relationship between classroom characteristics and speech intelligibility in order to optimize the amount of acoustic treatment and its position in the room. A rectangular shaped room was modeled with the ULYSSESS acoustic analysis software. Total sound level, first reflections, the difference between direct and reflected sound, reverberation time, ALCONs, and STI were calculated. The amount of absorption treatment and its position in the room, as well as the number of people in the room, were the variables studied. Results show that the amount of absorption treatment and the number of people in the room were much more important than the position of both the absorbent materials and the students to obtain good intelligibility scores. Nevertheless, for similar intelligibility scores, overall sound level is higher when the amount of absorbent material is controlled, allowing the listeners in the rear to benefit from higher speech levels. A reduction of 78% in the area of absorbent material can be achieved while maintaining the same STI score for all the positions in the room, with an increase in overall sound level of 4–5 dB.
Robust estimation of the cross-spectral density matrix from ambient noise using random matrix theory.
Authors: Menon R. , Gerstoft P. , Hodgkiss W. S.
Published: October 2010

It has been demonstrated that the empirical Green’s function can be retrieved by cross correlation of ambient noise. When working with ambient noise in the ocean acoustic environment, long periods of averaging are necessary to achieve a good SNR of the extracted Green’s functions. For an array of sensors, the cross-spectral density matrix (CSDM) contains the equivalent information in the frequency domain. In this paper, we use statistical methods using random matrix theory (RMT) to improve the estimate of the CSDM and hence increase the convergence of the empirical Green’s function to the true Green’s function.\\ In RMT, each element is considered a random variable and from this, features of the eigenvalue spectrum can be extracted. In this paper, we make use of the Marčenko–Pastur law of sample covariance matrices to analyze the eigenvalue spectrum of the CSDM and discard the part deemed to be just noise, based on the test hypothesis. Results are presented from the SW06 data.
Automatic detection of micro-emboli by means of a generalized autoregressive conditional heteroskedasticity model.
Authors: Girault J.-M. , Menigot S. , Deibine L.
Published: October 2010

Detection of micro-emboli is of great clinical importance to prevent cerebro-vascular events and to identify the causes of such events. Standard detection techniques implemented in the most commonly used systems are generally based on the passing of an energy threshold. The value of this threshold can be set just above the statistically highest detected energy of a Doppler signal related to circulating blood, i.e., during the systolic phase. This choice of threshold consequently prevents all detection of micro-emboli events whose energy might be lower than the systolic energy. The main idea of our technique was to test adaptively the whiteness of the prediction error between the Doppler signal and a synthetic signal obtained by a GARCH model. By assuming that micro-emboli are unforecasted, we hypothesize that embolic signals are unpredictable. We hypothesize that our new micro-emboli detector is a candidate technique to detect very small micro-emboli. We have tested and compared our new technique to the standard Fourier technique (Fourier). For a probability of detection fixed to 100%, the probability of false alarm of the standard automatic technique is 33% whereas the detector based on the GARCH model is less than 3%. This study demonstrates that our new technique detects micro-emboli hitherto not identified by classical methods.
Investigating the effects of intensity threshold on high-frequency three-dimensional power Doppler ultrasound.
Authors: El Kaffas Ahmed , Kwok Sheldon , Giles Anoja , Czarnota Gregory J.
Published: October 2010

High-frequency power Doppler ultrasound is a non-invasive vascular imaging modality ideal for a quantitative assessment of vascularity in preclinical models. Although it permits detecting slower blood flows than other ultrasound Doppler methods, it is limited by flow artifacts, complicating the interpretation of tumor vascularity metrics such as the vascularity index (VI). Our aim was to examine how parameters such as the intensity threshold affect the VI in in vivo xenograft models. Breast MDA-MB-231 tumors in the hind leg of SCID mice were treated with 0 or 8 Gy radiation, and imaged before and 24 h after treatment. A Vevo770 was used along with a 25-MHz center frequency transducer to obtain 3-D power Doppler images of tumors. Mice were again imaged while in the same position 1 min after sacrifice at 24 h. This was carried out for direct comparison of true blood flow signal to system noise level. The VI was computed for a range of intensity thresholds. The VI-threshold curves varied differently as a function of treatment, and preliminary data indicate an optimal plateau where the intensity threshold should be set, yielding a nearly true blood flow signal and minimizing noise signal. [Work funded by the Canadian Breast Cancer Foundation.]
Teaching acoustics in Argentina.
Authors: Gavinowich Daniel , Vechiatti Nilda
Published: October 2010

In Argentina, the teaching of acoustics is included in the curricula of several academic institutions, being a part of the technical instruction received both in undergraduate and graduate majors. Acoustics is part of numerous college and technical careers, several of which will be detailed during this presentation. At the same time, a large number of post graduate and extension training classes are offered by the same and other institutions. It is only fair to mention that the Engineering School of the Buenos Aires University was the pioneer in teaching this discipline in Argentina, when Electroacoustics started to be taught in 1956 as a mandatory subject in the formerly joint Electronics Engineering plan, thus enabling the formation of the Acoustic and Electroacoustic Laboratory of the Faculty, a laboratory that still exists. Shortly after, in October 1961, the Acoustic and Lighting Research Center was founded in the Architecture and Urbanism School at the Cordoba National University. The extensive growth and ramifications we have seen so far make the list unavoidably incomplete, since the present possibilities of learning this science in the country is too large to be exposed, allowing us a reduced mention and a brief exposure.
A theoretical course in underwater acoustics based on the sonar equation.
Authors: Isakson Marcia J.
Published: October 2010

Current underwater acoustics students require a theoretical knowledge of propagation, scattering, and target strength as well as practical knowledge of how these concepts are applied in the modern sonar system. A curriculum based on the sonar equation was developed at the University of Texas, which includes theoretical propagation methods such as ray theory and normal modes, important oceanographic phenomena, target and interface scattering, sonar signal processing, and basic sonar design. This curriculum is described in order to spur a discussion of teaching for the modern underwater acoustics student.
Periodicity series of initial transients of musical instruments for real-time implementation.
Authors: Bader Rolf
Published: October 2010

A real-time algorithm for initial transients of musical instruments displaying the periodicity changes of the system during the transient is presented as shown with blown instruments. When the system consists of a reed and an air column, the standpoint of the reed is taken and only one equation formulates the action of the reed upon itself as delayed and damped via the air column. A general system variable is used which includes both the periodicity and the amplitude of the system. This is possible as a back impulse acting in-phase with the reed will not only cause an enlargement of the reed’s amplitude but will in accordance with this enlargement also lead to an enlargement of the reed’s periodicity. When using an exponential damping and solving the equation for the system parameter of the next time step, an equation similar to that of the logarithmic map appears. According to the system parameters, for the steady state, a whole bifurcation scenario occurs with stable, bi-stable, and chaotic motion representing a stable tone, a multiphonic, or a blowing noise. When formulated for instruments with multiple reflection points, such as violins or guitars, depending on the delays and dampings, the system shows an astonishing stability over the whole playing range because of these multiple reflections.
Sound separation by humming.
Authors: Smaragdis Paris , Mysore Gautham
Published: October 2010

We present a novel interface for selecting and isolating sounds from complex audio mixtures. Traditional interfaces in audio editors provide graphical representations of sounds through which a user might be able to visually identify elements of sounds in a mixture; they do not, however, facilitate object-specific editing (e.g., selecting only the voice of a singer in a song). The proposed interface uses audio guidance from a user in order to specify a target sound within a mixture. The user is asked to vocalize the desired target sound, and an automated process identifies and isolates the elements of the mixture that best relate to the user’s input. Such a tool makes the extraction of complex sources an easier process than using graphical tools or statistical source separation models.
Scattering of infrasound waves by anisotropic inhomogeneities of the atmosphere.
Authors: Chunchuzov Igor , Kulichkov Sergey , Popov Oleg , Waxler Roger , Assink Jelle
Published: October 2010

The shaping mechanism for anisotropic wind velocity and temperature fluctuations of the atmosphere and their effect on the long-range infrasound propagation are studied. Based on the model developed for the wind velocity and temperature fluctuations induced by atmospheric gravity waves in the middle and upper atmosphere, the acoustic fields from pulsed infrasound sources (such as ground-surface explosions and volcanoes) are calculated by a parabolic equation method at different ranges from the sources (up to 300 km). The scattering of infrasound signals by highly anisotropic wind velocity and temperature inhomogeneities existing in the stratosphere and lower thermosphere is shown to significantly contribute to the stratospheric and thermospheric arrivals of the signal.
Flexible light-weight multi-element/multi-path structures to reduce noise and vibration.
Authors: Bliss Donald B. , Franzoni Linda P. , Palas Cassidy M. , Michalis Krista A.
Published: October 2010

Sound and vibration transmission can be reduced by dividing a structural barrier into several constituent subsystems with separate, but coupled, wave transmission paths. Multi-element/multi-path (MEMP) structures utilize the inherent dynamics of the system, rather than damping, to achieve substantial reduction over a wide frequency range, while satisfying constraints on static strength and weight. The higher order and increased complexity of MEMP structures afford a wealth of opportunities for vibration and noise reduction, but the approach requires rethinking the structural design process. Simulations show the existence of robust solutions that provide surprisingly large wide-band reductions. Attenuation is achieved through a variety of processes acting in concert: different subsystem wave speeds, mixed boundary conditions at attachment points, interaction through elastic couplings, cross-coupling of applied forcing, and cross-communication between subsystems to modify acoustic radiation. The dynamics of the air between the layers of an MEMP barrier, particularly how the structure is ventilated to achieve acoustic cross-communication, can strongly affect performance and is an important issue in the modeling and design. Preliminary experimental results show that the concept is practical and promising, and may have application in automotive and aerospace vehicles.
Energy transport and statistics in the acoustics of large irregular structures.
Authors: Weaver Richard L.
Published: October 2010

There is a long-standing presumption that the acoustics of large irregular structures are well approximated by a theory of diffuse spectral energy density, for which one may write balance and constitutive relations, neglecting wave phase. This is the basis for SEA. But this picture fails to predict numerous important phenomena (normal modes, level repulsion, enhanced backscatter, localization, retrieval of the Greens function, etc.) Such theories are furthermore derivable from first principles only in certain special limits, e.g., statistical thermodynamics in which the acoustic fields are thermal fluctuations. The question thus arises as to whether one can derive a more accurate and universal theory. In the non-dissipative limit (which can be relaxed a posteriori) one can impose an additional constraint on acoustic transfer functions; i.e., that they conserve energy. S-matrices must be unitary. This condition re-inserts phases that SEA neglects. It is shown that, in the case in which there is a single source/receiver, this imposition has a plethora of consequences, amongst them being normal modes, level repulsion, enhanced backscatter, and localization. We discuss attempts to extend this to the case of multiple sources and receivers.
The effect of reverberation on Quick Speech-in-Noise test and Revised-Speech Perception in Noise test scores in young adults with normal hearing.
Authors: Morlas Holly A. , Adams Elizabeth M.
Published: October 2010

In typical, realistic listening environments, speech perception is often degraded by various degrees of both noise and reverberation. The effect of reverberation has previously been assessed with predictability measures, such as the speech transmission index (STI). [Houtgast et al. (1980); Steeneken and Houtgast (1980).] Currently, no clinical test measure of an individual’s speech perception ability incorporates both noise and reverberation. The aim of the present study is to provide a more real-world measure of speech perception performance with the inclusion of reverberation on two speech-in-noise tests. The Revised-Speech Perception in Noise Test [R-SPIN; Bilger et al. (1984)] and the Quick Speech-in-Noise Test [QuickSIN; Etymotic Research (2001)] are administered in multitalker babble at various signal-to-noise ratios (SNRs) and reverberation times in young adults with normal hearing. Results of the QuickSIN and R-SPIN tests indicate that reverberation negatively impacts speech perception but is dependent upon other characteristics of the listening environment, such as the poor SNR, sentence stimuli lacking contextual cues, or both. Overall findings suggest that the inclusion of reverberation would provide a more realistic clinical tool of speech perception accuracy and validate patient complaints of poor speech perception in degraded listening environments.
Binaural speech intelligibility as a function of speaker angle and interaural cross-correlation of disturbing noise and reverberation.
Authors: Padilla Laura , Orduña Felipe
Published: October 2010

Subjective intelligibility tests were carried out that demonstrate that binaural speech intelligibility under adverse acoustic conditions, such as noise and reverberation, improves when listening at an angle, and also depends on the interaural cross-correlation of the disturbance. Speech material was binaurally recorded in an anechoic chamber using an acoustic manikin, from a loudspeaker at different azimuth angles from −60 deg (left) to +60 deg (right) in 15-deg steps. The binaural speech material was contaminated with interaurally correlated and uncorrelated noise and reverberation, and was presented to listeners through headphones. Results indicate advantages of binaural speech intelligibility under adverse acoustic conditions when listening at an angle, relative to listening at 0 deg. Additionally, speech intelligibility improves when the disturbing reverberation has high interaural cross-correlation; while on the other hand, speech intelligibility improves when the disturbing noise has low interaural cross-correlation.
The relative contribution to speech intelligibility from consonants and vowels using synthesized and naturally spoken sentences.
Authors: DiGiovanni Jeffrey J. , Prewitt Jessica M. , Moates Daniel R.
Published: October 2010

Several studies have attempted to understand why intelligibility is maintained in sentences or words in which all consonants were replaced by silence or noise. Studies have traditionally used naturally spoken stimuli to study these effects. Cole et al. (1996) found that when sentences were presented with only vowels or only consonants intact, participants performed significantly better in the vowel only condition. Others [Kewley-Port et al. (2007); Fogerty and Kewley-Port (2009); Lee and Kewley-Port (2009)] have attempted to assess the source of intelligibility improvements for the vowel only conditions without conclusive results. Naturally spoken stimuli have multiple imbued cues that are difficult to control and thus present challenges in teasing out the relative contributions of each cue. It has been proposed that synthesized speech may provide a method to assess the specific contribution of the cues included in consonants and vowels to speech intelligibility. The goals of this study were to determine if the intelligibility scores were the same for similarly processed synthesized and naturally produced sentences, and to define the extremes of intelligibility using different synthesis techniques. Participants performed similarly in synthesized and naturally produced speech conditions, supporting the use of synthesized speech in determining the relative contribution of vowel cues.
Presence of preceding sound affects the neural representation of speech sounds: Behavioral data.
Authors: Carbonell Kathy M. , Aravamudhan Radhika , Lotto Andrew J.
Published: October 2010

Traditionally, context-sensitive speech perception has been demonstrated by eliciting shifts in target sound categorization through manipulation of the phonemic/spectral content of surrounding context. For example, changing the third formant frequency of a preceding context (from /al/ to /ar/) can result in significant shifts in target categorization (from /ga/ to /da/). However, it is probable that the most salient difference in context is between the presence or absence of any other sound. The question becomes whether this large change in context has substantial effects on target categorization as well. In the current study, participants were asked to categorize members of a series of syllables varying from /ga/ to /da/ presented in isolation or following /al/, /ar/, or /a/. The typical shifts in categorization were obtained for /al/ vsersus /ar/ contexts, but the shift in response between isolated presentation and any of the audible context conditions was much larger (with more /da/ responses in isolation). A similar pattern of results was obtained when the audible context was broadband noise. Additionally, slopes of categorization functions were less steep for isolated syllables than when preceded by speech. These results suggest that isolated syllables may be neurally encoded differently than the same syllables in context.
Presence of preceding sound affects the neural representation of speech sounds: Frequency following response data.
Authors: Aravamudhan Radhika , Carbonell Kathy M. , Lotto Andrew J.
Published: October 2010

A substantial body of literature has focused on context effects in speech perception in which manipulation of the phonemic or spectral content of preceding sounds (e.g., /al/ versus /ar/) result in a shift in the perceptual categorization of a target syllable (e.g., /da/ versus /ga/). In a previous study utilizing the frequency-following response (FFR) to measure neural correlates of these context effects [R. Aravamudhan, J. Acoust. Soc. Am. 126, 2204], it was noted that the representation of target formant trajectories were much weaker when the stimulus was presented in isolation versus following some type of context. To examine this effect explicitly, a series of syllables varying from /da/ to /ga/ was presented to listeners either in isolation or following the syllables /a/, /al/, or /ar/ (with a 50-ms silent gap between context and target). FFR measures were obtained from EEG recordings while participants listened passively. The resulting narrow-band spectrograms over the grand averages demonstrated that the target formant representations were much weaker or absent when presented in isolation. This counter-intuitive result may indicate the importance of context for robust encoding of important spectral features in speech and provide a cautionary note on the use of isolated syllables in auditory testing.
Design and evaluation of reference populations with forensic purposes.
Authors: Rosas Claudia , Sommerhoff Jorge
Published: October 2010

The present work analyzed the effect of sex, noise, vocal register, and channel on the performance of Batvox, the automatic speech recognizer employed by the Forensic Laboratory of the Investigative Police of Chile. This study transferred and applied the methodology and results of a previous and recently finished research project [Regular Fondecyt No. 1,070,210, funded by the National Commission for Scientific and Technological Research of the Government of Chile] to develop a model for the generation of speech reference populations with forensic purposes, which incorporated a set of dialect and environmental variables not considered in the selected samples currently integrating their databases. The information supplied provided methodological criteria to develop an optimized database for the biometric identification of speakers in Chile and to improve the performance of the systems applying them.
A novel tonality estimation method of spectral components for audio coding applications.
Authors: Kulesza Maciej , Czyzewski Andrzej
Published: October 2010

A novel algorithm providing adequate tonality estimates for constant and modulated sinusoidal components was developed. The proposed algorithm was combined with the MPEG psychoacoustic model 2 in order to verify whether replacing the standard tonality estimator with the proposed one leads to a more reliable estimate of hearing threshold. It was verified whether the proposed tonality estimation algorithm may be used as a basis for detecting the signal bands containing only a noise-like component that can be encoded according to the perceptual noise substitution technique. Subsequently, it was proved that it is possible to estimate the tonality of unmodulated or frequency-modulated sinusoidal components of audio signals through the comparison of their instantaneous frequency variations determined employing both an estimator processing spectral amplitude samples and an estimator processing spectral phase samples. It was also revealed that distortions introduced during perceptual audio coding may be effectively limited employing the proposed tonality estimation algorithm. In order to fully explore the benefits of the proposed method for coding applications, the listening tests were performed in accordance with the ITU-T BS.1534 recommendation. [Research partially funded by the Polish Ministry of Science and Higher Education within Grants Nos. PBZ-MNiSW-02-II-2007 and No. N N517 378736.]
Scattering from inclusions in stratified marine sediments.
Authors: Ivakin Anatoliy
Published: October 2010

The role of discrete scatterers in marine sediments is evaluated based on acoustic and environmental measurements at the shallow water sediment acoustics experiment, SAX04, and shown to be significant. The sediment at the SAX04 site was complicated and characterized as a stratified medium quartz sand/mud mixture with the presence of a small volume portion of carbonate shells and shell fragments. The sediment particle analysis provided the size and shape distributions for shells, which are used as inputs to a model of incoherent discrete scattering from inclusions in stratified sediments. The model considers inclusions as sparsely distributed, relatively large, randomly oriented particles of irregular shape embedded in a water-saturated sediment matrix comprised of much smaller (comparing to both wavelength and the size of inclusions) grains. Sound propagation in the sediment matrix is described as in an effective fluid with parameters corresponding to the SAX04 stratified medium sand/mud environment. Using this approach, it is demonstrated that scattering from shells in general is capable of providing a reasonable explanation of both frequency and angular dependencies of the SAX04 bottom backscattering strength in a wide range of grazing angles (15–50 deg) and frequencies (30–200 kHz). [Work supported by ONR.]
Simultaneous passive and active detection and localization of humpback whales using data recorded on a towed horizontal receiving array.
Authors: Gong Zheng , Chauhan Hari , Makris Nicholas , Ratilal Purnima
Published: October 2010

A large number of marine mammal vocalizations, most likely from humpback whales, were passively recorded by a towed horizontal receiver array during the ocean acoustic waveguide remote sensing (OAWRS) Gulf of Maine 2006 Experiment. Spectral analyzes show that most of the vocalizations were random broadband signals with short time duration, typically lasting 1–2 s in the 300–600-Hz frequency range. The array invariant method [Lee and Makris, J. Acoust. Soc. Am. (2006)] is applied to localize the whales in bearing and range after conventional plane-wave beamforming and matched filtering of passively recorded vocalizations on the array. The source levels of a sequence of whale calls in a 110-min time period, belonging to a number of individuals, are estimated based on the localization results. The estimation results are consistent with previous studies. We also examine the feasibility of actively detecting and localizing whales with OAWRS at low-to-mid frequencies in a random range-dependent ocean waveguide. A full-field waveguide scattering model is applied to determine the scattered field level from whales, as a function of range and depth location of the whale, and compared to environmental reverberation measured in the Gulf of Maine. The dominant source of scattering from whales at these frequencies is their air-filled lungs.
A modular computational acoustic model of ancient Chavín de Huántar, Perú.
Authors: Kolar Miriam A. , Abel Jonathan S. , Huang Patty , Rick John W. , Smith Julius O. , Chafe Chris
Published: October 2010

Inspired by on-site observations and measurements, a computational acoustic model of the interior architecture of the 3000-year-old ceremonial center at Chavín de Huántar, Perú is presented. The model addresses the foundational study by Lumbreras et al. (1976) which posited an acoustic system integral to Chavín architecture involving “a network of resonance rooms connected by sound transmission tubes.” We propose a translation of the topology of Chavín gallery forms to a modular computational acoustic model based on bi-directional digital waveguides, representing the corridors and ducts, connected through reverberant scattering junctions, representing the small rooms. This approach combines known architectural dimensional and material data with representative measured acoustic data, thus economizing the collection of impulse response measurements required to accurately simulate site acoustics. Applications include virtual acoustic reconstruction of inaccessible or demolished site structures, and auralizations of hypothesized architectural forms, allowing any desired sound sample to be “played back” in the modeled acoustic context.
Acoustical solutions to archaeological mysteries at Chichen Itza’s temple of Kukulkan.
Authors: Lubman David
Published: October 2010

Archaeoacoustics adds value when it solves problems that stump archaeologists. At the spring equinox, a mysterious zigzag shadow creeps down a staircase balustrade at the temple of Kukulkan. The shadow represents the Mesoamerican plumed serpent god Kukulkan—or Quetzalcoatl—descending from the heavens. Is that famous shadow accident or design? Despite compelling ethnographic ties linking the equinox display with ancient Maya culture, archaeologists have found no evidence of intentional design. Such evidence was found by relating a peculiar aural clue at the temple’s chirped echo-to Maya ethnohistory. The chirped echo emulates the call of the quetzal—the venerated bird messenger of the Maya gods, whose spectacular diving behavior at the spring equinox gives it the visage of a flying serpent. The echo is of cognitive interest as well. Echoes are normally taken in stride; not so the chirped echo. To many visitors it seems unnatural, even supernatural, for an echo to sound radically different than the stimulus, as if one’s handclap was answered by an invisible sentient being. If this echo can evoke numinous (spiritual) experiences in contemporary listeners without ties to the Maya, was it more powerful to the ancients for whom the sound was iconic?
Acoustical characterization of the archaeological sites “Plazuelas” and “Peralta” in Guanajuato, Mexico.
Authors: Ramos Alejandro , Medina Andres
Published: October 2010

This paper will present the work to be done on the sites “Plazuelas” and “Peralta”, both in Guanajuato, Mexico. The objective is to develop an archaeocustical characterization of the archaeological areas, as well as the musical instruments found in these sites. Furthermore, an ethnomusicologic and historiographic investigation will be done. In adition, it will present the methodology and protocol to be followed in this investigation.
Analysis of the acoustic response generated by the stairs of El Castillo of Chichen-Itza in relation to the sound source.
Authors: Ruiz A. Tonatiuh , Ramos Alejandro , Medina Andrés A. , Padilla Pablo
Published: October 2010

When a person claps in front the rebuild stairs of El Castillo in Chichen-Itza, a chirp echo similar to the song of a quetzal is produced. This acoustic effect has been studied by many authors and some of them have proposed physical models to explain it. The simulations generated by these models were compared only with a recording using a handclap as sound source. In this work we analyze the response of the acoustic effect to different sound sources, and we propose a model based on a linear array of N point sources to simulate this response. A series of Gaussian pulses with different spectral distributions was reproduced and recorded in situ. It was found that above a frequency related to the steps dimensions, the acoustic response is temporally prolonged, and depending on the spectral distribution of the pulse, the response may result in a frequency sweep with one or more harmonics. Comparing the recordings with the simulations, it was found that the general characteristics of the acoustic response were reproduced by the model. With the results of this work, it is possible to know how the sound source, the stair dimensions, and receptor position are related with the acoustic effect.
Wave energy and underwater noise: Assessment and monitoring aspects.
Authors: Patricio Sofia , Soares Cristiano
Published: October 2010

After several decades of research, wave energy has reached a pre-commercial stage, emerging as a potential industry for the future. Despite the wave energy being considered as an environmentally friendly activity, it will probably have positive and negative aspects. The marine environment is an important area of biological diversity, hence the concern about the possible effects of underwater noise has increased among developers and promoters. While it is not expected that each individual device will produce a high level of noise, the deployment of several devices in the same farm, operating day and night, may have an effect on the fauna. However, the acoustic characterization of wave energy devices (WEDs) is not trivial; the noise generated and propagation will depend on oceanographic characteristics and operational conditions. The acoustic signature of each WED is expected to be produced from a variety of different components (mechanical or other moving parts) related to the device itself or by its interaction with the environment. Just after the characterization of the noise emitted by the WEDs and potential coincidence with the hearing sensitivity range of marine animals, a first assessment of possible impacts on the animals can be attempted.