bluuebunny/crossref_metadata_2025 huggingface dataset:
The influence of adjacent structure on the response of insonified fish and marine mammal resonant cavities
Authors: Garrelick Joel
Published: October 2013

It has long been known that the acoustic response of, and scattering from, finite elastic structures and cavities may be enhanced at their submerged natural frequencies, that is, at resonance. Fish and marine mammal cavities, viz., air bladders and lungs, respectively, are prime examples. In either case, classic analyses represent the cavity as being in an otherwise free field and spherical in geometry, initially as well as in its deformed state. Such simplifying assumptions may be invalidated by the presence of adjacent structure, whether or not such structure is transparent to the incident wave. This is especially the case for local response functions, namely stresses and strains in surrounding tissue, as opposed to say the acoustically scattered return. A strong sensitivity of these response functions to the assumed geometry compounds the problem. These issues are analytically examined in this paper for the example of a plane acoustic wave incident on a membrane-sheathed cavity located adjacent to structure of prescribed high or low impedance. Predictions for the scattered acoustic field and cavity stress/strains are compared to classic free field values. Enhanced levels are computed and interpreted in terms of mode coupling to higher order membrane/cavity vibration modes.
Observations of frequency shift associated with schooling fish
Authors: Diachok Orest
Published: October 2013

The number of sardines per school, N, is nominally 10000 and the separation between sardines in school, s, is nominally 1 fish length, L⋅s is much smaller than the wavelength at f (the resonance frequency of individuals), which suggests that schools may exhibit acoustic properties of bubble clouds. Long-term, broadband transmission loss measurements at a shallow-water site in the Gulf of Lion revealed absorption lines due to dispersed sardines at 1.3 kHz at 20 m at night and 2.7 kHz at 65 m at dawn. Temporal changes in observed values of f were consistent with concurrent echo sounder observations of the vertical migration of sardines, and theoretical computations based on laboratory measurements of swim bladder dimensions. The measured resonance frequency of sardines in schools during daytime, 1.7 kHz at 65 m, was 0.6f at the same depth at dawn. The observed frequency shift is consistent with a hybrid model of the fundamental resonance frequency of a bubble cloud, which is based on theories developed by Feuillade, Nero, and Love (1996) and dAgostino and Brennan (1988), and s=0.8 L and N=5000 fish per school. [Work supported by ONR.]
Vibration amplitude sonoelastography lesion imaging using low-frequency audible vibration
Authors: Taylor Lawrence , Parker Kevin
Published: October 2013

Sonoelastography or vibration amplitude imaging is an ultrasound imaging technique in which low-amplitude, low-frequency shear waves, less than 0.1-mm displacement and 1-kHz frequency, are propagated deep into tissue, while real time Doppler techniques are used to image the resulting vibration pattern. Finite-element studies and experiments on tissue-mimicking phantoms verify that a discrete hard inhomogeneity present within a larger region of soft tissue will cause a decrease in the vibration field at its location. This forms the basis for tumor detection using sonoelastography. Real time relative imaging of the vibration field is possible because a vibrating particle will phase modulate an ultrasound signal. The particle’s amplitude is directly proportional to the spectral spread of the reflected Doppler echo. Real time estimation of the variance of the Doppler power spectrum at each pixel allows the vibration field to be imaged. Results are shown for phantom lesions, thermal lesions, and 3-D in vitro and 2-D in vivo prostate cancer. MRI and whole mount histology is used to validate the system accuracy.
Simulation of singing qualities governed by lower vocal tract adjustments
Authors: Titze Ingo R.
Published: October 2013

In previous meetings, voice qualities such as pressed, ring, yawn, and twang were discussed in a speech context. It was shown that these qualities have unique spectral characteristics brought about by combinations of glottal and lower vocal tract adjustments (the epilarynx tube and the pharynx). Yawn has a wide glottis, a wide epilarynx tube, and a wide pharynx. On the contrary, twang has a general narrowing of all these airway sections. Ring has a wide pharynx and a relatively narrow epilarynx tube. A pressed voice is primary laryngeal, with a narrowed glottis. In this presentation, similar adjustments are made for singing with a voice simulator that controls vocal tract area functions and glottal flow pulses by rules. Results suggest that various singing styles, such as country-western, opera, or pop, may in part be characterized by these unique combinations of source and filter adjustments.
Acoustic and aerodynamic characteristics of Country-Western, Operatic and Broadway singing styles compared to speech
Authors: Stone Robert E. , Cleveland Thomas F. , Sundberg P. Johan
Published: October 2013

Acoustic and aerodynamic measures were used to objectively describe characteristics of Country-Western (C-W) singing in a group of six premier performers in a series of studies and of operatic and Broadway singing in a female subject with professional experience in both styles of singing. For comparison purposes the same measures also were applied to individuals while speaking the same material as sung. Changes in pitch and vocal loudness were investigated for various dependent variables, including subglottal pressure, closed quotient, glottal leakage, H1–H2 difference [the level difference between the two lowest partials of the source spectrum and glottal compliance (the ratio between the air volume displaced in a glottal pulse and the subglottal pressure)], formant frequencies, long-term-average spectrum and vibrato characteristics (in operatic versus Broadway singing). Data from C-W singers suggest they use higher sub-glottal pressures in singing than in speaking. Changes in vocal intensity for doubling sub-glottal pressure is less than reported for classical singers. Several measures were similar for both speaking and C-W singing. Whereas results provide objective specification of differences between operatic and Broadway styles of singing, the latter seems similar to features of conversational speaking style.
Analysis and enhancement of country singing
Authors: Lee Matthew , Smith Mark J. T.
Published: October 2013

The study of human singing has focused extensively on the analysis of voice characteristics. At the same time, a substantial body of work has been under study aimed at modeling and synthesizing the human voice. The work on which we report brings together some key analysis and synthesis principles to create a new model for digitally improving the perceived quality of an average singing voice. The model presented employs an analysis-by-synthesis overlap-add (ABS-OLA) sinusoidal model, which in the past has been used for the analysis and synthesis of speech, in combination with a spectral model of the vocal tract. The ABS-OLA sinusoidal model for speech has been shown to be a flexible, accurate, and computationally efficient representation capable of producing a natural-sounding singing voice [E. B. George and M. J. T. Smith, Trans. Speech Audio Processing 5, 389–406 (1997)]. A spectral model infused in the ABS-OLA uses Generalized Gaussian functions to provide a simple framework which enables the precise modification of spectral characteristics while maintaining the quality and naturalness of the original voice. Furthermore, it is shown that the parameters of the new ABS-OLA can accommodate pitch corrections and vocal quality enhancements while preserving naturalness and singer identity. Examples of enhanced country singing will be presented.
Fan broadband noise from the ingestion of inhomogeneous turbulence
Authors: Lynch D. A. , Blake W. K. , Martinez R.
Published: October 2013

Calculations of broadband noise from pre- and post-swirl turbomachines are compared to recent wind-tunnel data. The inflow cases addressed are: (1) grid-generated turbulence for which near-homogeneous conditions prevailed (for the pre-swirl case); and (2) sharply inhomogeneous turbulence encapsulated within the wakes of the rotating upstream blades (for the post-swirl case). Computed results help explain the degree to which strip aerodynamics succeeds in reproducing the noise data, particularly upon comparison to more rigorous estimates that account for spanwise wave numbers in the flow-to-lift transfer function. The paper also reports on the merit of basing the calculation of broadband noise on a circumferentially averaged inflow for case (2), whose turbulence is thereby rendered artificially homogeneous. The presentation ends with a discussion of the experimental and numerical means whereby the size of the predominant integral scale of the wake-encapsulated turbulent flow was determined, and the extent to which the two sets of values agreed.
Sources of flow noise due to time-varying tip relief
Authors: Martinez R.
Published: October 2013

This paper begins with a brief review of the conventional cause of shed vorticity in two-dimensional unsteady lifting flows around airfoils. It then poses the following three-dimensional theoretical problem in support of experimental work recently conducted at Penn State/ARL: Take a wing tip of arbitrary three-dimensional shape and place a wall near it such that its plane is normal to that of flight. Let the wall be sinusoidally corrugated in the direction of the flow and be convected by it, so that an observer stationed on the wing’s tip experiences time-varying influences determined by the wall’s passing serpentine pattern. Our presentation will describe a linearizing perturbation analysis whereby the ratio of the wall’s sinusoidal amplitude to its wavelength becomes a small parameter. The zeroth-order problem becomes then one of steady three-dimensional aerodynamics barring the presence of external fluctuations. The first-order problem is fundamentally unsteady and driven, as usual, by the zeroth-order one. An unconventional source of flow noise emerges: the ultimately unacceptable axial changes in the strength of trailing vortices, as brought about by their irregular images behind the corrugated wall, lead to new neutralizing shed vortices and harmonic lift.
Sound quality metric development for the Air Conditioning and Refrigeration Institute
Authors: Hodgdon Kathleen K. , Burkhardt Russell C.
Published: October 2013

The current method of assessing acoustic signatures from residential air conditioning units is defined in the Air Conditioning and Refrigeration Institute (ARI 270) 1995 Standard for the Sound Rating of Outdoor Unitary Equipment. This research project was designed to assess the efficacy of the metric to predict consumer preference. The original metric and modified versions of that metric were evaluated as tools for use in today’s market. The ARI 270 metric was implemented in software with additional features and the flexibility to modify the features applied. Numerous product acoustic signatures were analyzed and compared using the original metric and various modifications of that metric. As a result of that analysis a set of synthesized signatures was generated that targets problem areas for an application of the metric to typical signature configurations. A subjective jury evaluation was conducted to establish the consumer preference for those synthesized signatures. A statistical correlation of the various configurations was conducted to assess the degree of the relationship between the subjective preferences and the various metric calculations. Recommendations were made for modifications to improve the current metric’s ability to predict a subjective preference. [Programming completed by Jonathan Peters (ARL/PSU). Research supported by ARI.]
Aircraft system noise prediction: Past, present, and future
Authors: Golub Robert A. , Posey Joe W.
Published: October 2013

Aircraft system noise prediction is necessary to estimate the community noise impact of future aircraft and to estimate the noise impacts of changes in propulsion systems, airframes, or operations of current aircraft. Aircraft system noise is the sum of noise generated by various components of the propulsion system and the various components of the airframe including the landing gear. Predicting noise on the ground from an aircraft flyover requires estimating the noise generated by the many contributing sources during the flyover as the flight conditions change, summing these sources as a function of time, and propagating the resultant combined source through the atmosphere to the observer location. NASA introduced the Aircraft Noise Prediction Program (ANOPP) about 30 years ago and continually upgraded and extended the code prediction capability. The history of ANOPP will be reviewed along with current efforts to make it more useful as a design tool. A proposed new systems prediction program, AVATAR, will be less empirical and capable of predicting community noise from unconventional aircraft planforms. Innovative/unconventional aircraft configurations will be required to meet aggressive noise goals in the future.
Prediction-based aircraft flyover noise synthesis
Authors: Rizzi Stephen A. , Sullivan Brenda M.
Published: October 2013

Investigation of community noise impact of aircraft flyover noise through subjective testing requires time histories of the acoustic pressure at one or more listener positions. The use of recorded aircraft flyover noise for this purpose is often problematic. Factors contributing to this include extraneous noise in the recordings (natural or man-made), a finite number of fixed recording positions, and the cost of conducting the flight test. Perhaps the most limiting factor is the inability to examine proposed aircraft, engines, flight procedures, and other conditions or configurations for which recorded data are unavailable. Synthesis of aircraft flyover noise as an alternative to recordings is thus desirable. An approach to the synthesis of broadband and narrowband aircraft component noise is presented based upon output from community noise prediction codes. These codes typically calculate aircraft flyover noise at designated listener positions in the frequency domain. The necessity to convert these to the time domain presents two challenges both relating to the fact that the predictions are, in essence, time averaged. The first of these involves the reconstruction of phase. The second is the synthesis of temporal fluctuations known to exist in real data. A semiempirical approach to calculating these effects is also presented.
The use of an infrasound microphone array to study wind noise spectra and correlation
Authors: Shields F. Douglas , Talmadge Carrick
Published: October 2013

A three dimensional array of infrasound sensors of original design has been constructed and used to study wind generated pressure signals in the frequency range from 0.1 to 100 Hz. The ten sensors in each arm of the array are 2 feet apart. An ultrasonic anemometer ten feet off the ground was used to make simultaneous measurements of the three components of the wind velocity. Several sets of data have been taken in open fields with different ground cover. The data have been spectrally analyzed and, over a limited frequency range, the velocity and pressure variations found to obey the 5/3 and 7/3 power law that is expected for the inertial range. A study has also been made of the dependence of the correlation between the pressure signals and the sensor separation. The coherence of the pressure signals indicates that the convection velocity is nearly independent of frequency, and the correlation has an exponentially decaying sinusoidal dependence on the sensor separation. The array has also been used successfully to localize infrasound sources. [Work supported by the U.S. Army Armament Research Development and Engineering Center.]
Influence of turbulence frequency and flow unsteadiness on noise reduction of windscreens
Authors: Zheng Z. Charlie , Zhang Ning
Published: October 2013

Windscreens are widely used in outdoor microphone measurement. However, in many of these applications, low-frequency wind noise interferes with the signals and the performance of measurement microphones significantly depends on the correct design of the windscreen that is used to maximize the signal-to-noise ratio of the sensing system. There are two possible noise sources around a windscreened microphone: one is from the turbulence carried in the incoming flow; the other is from the wake vortex shedding due to interaction between the windscreen and the wind. Recently, we investigated the effects of windscreens on low-frequency wind noise reduction using a steady-state computational fluid dynamic model. The justification of the use of a steady-state flow model was based on experimental data by Morgan and Raspet that showed that when the corresponding frequency was below 10 Hz, the wind noise reduction was almost constant. Under this low-frequency assumption, we found that the wind noise reduction increases with decrease of the Reynolds number. We are currently concentrated on higher frequencies where the wind noise reduction is no longer independent of frequencies and unsteady fluid dynamics is required to provide pressure fluctuation information on the windscreen surface.
Jozef Zwislocki: Impact on models of coding in the auditory nerve
Authors: Sachs Murray B.
Published: October 2013

The auditory nerve has long been considered a window on the biophysical mechanisms of cochlear transduction and the most carefully characterized aspect of the responses of single auditory-nerve fibers has been the tuning curve. Perhaps the most intensively studied question in auditory theory is: What is the relationship between the shapes of these tuning curves and basilar membrane displacements? The basilar membrane measurements of Georg von Bekesy stimulated a generation of basilar-membrane modelers, none more notable than Joe Zwislocki, who was awarded the first von Bekesy Medal by the Acoustical Society in 1985. The impact of Zwislocki’s basilar membrane models on our understanding of auditory nerve tuning will be reviewed. The properties of auditory-nerve discharge patterns are also shaped by the filtering properties of the hair cell/synapse complex. The major contributions of Joe and his students to our understanding of this filtering through their elegant experimental and modeling studies of adaptation in the auditory nerve will be presented. Throughout his career, Joe Zwislocki has maintained an active interest in loudness summation and his work in relating the input/output characteristics of auditory-nerve fibers to loudness will be highlighted.
Understanding loudness: Testing physiological models of intensity discrimination and masking for their consistency with loudness functions
Authors: Carney Laurel H.
Published: October 2013

Joe Zwislocki continues to contribute actively to ongoing scientific discourse at the Institute for Sensory Research (ISR). Naturally, these discussions include, amongst other topics, the relationship between loudness and intensity discrimination. Being in the ISR environment has provided the motivation to test models for intensity discrimination and masking in the context of loudness. This problem is timely in that it relates to Joe’s current efforts to assemble a written summary of his contributions to the study of loudness. In this presentation, the ability of recent neural models for intensity discrimination and masking to explain some basic aspects of the loudness functions reported by Joe Zwislocki and his colleagues will be explored. [Work supported by NIDCD-NIH.]
Parallel iterative solution of large-scale acoustic scattering problems using exact non reflecting conditions on distributed memory computer systems
Authors: Ianculescu Cristian , Thompson Lonny L.
Published: October 2013

Parallel iterative methods for fast solution of large-scale acoustic radiation and scattering problems are developed using exact Dirichlet-to-Neumann (DtN) nonreflecting boundaries. For elongated scatterers such as submarines, it is shown that the generalization of the DtN to elliptical/spheroidal artificial boundaries improves significantly the computational efficiency of accurate finite element methods for the solution of acoustic scattering problems. The outer-product structure of the DtN map is exploited as a low-rank update of the system matrix to efficiently compute the matrix-by-vector products found in Krylov subspace based iterative methods. For the complex non-Hermitian matrices resulting from the Helmholtz equation, a distributed-memory parallel BICG-STAB iterative method is used in conjunction with a hybrid parallel SSOR/Jacobi preconditioner. The domain decomposition with interface minimization was performed to ensure optimal inter-processor communication. For the distributed memory architectures tested, including Linux/Intel Beowulf clusters, when implemented as a low-rank update, the nonlocal character of the DtN map shows little impact on the scale up or parallel efficiency compared to approximate local boundary conditions. [Work supported by NSF.]
Further developments of a high-frequency broadband energy-intensity boundary element method
Authors: Rouse Jerry W. , Franzoni Linda P.
Published: October 2013

The prediction of the spatial mean square pressure distribution within enclosed high-frequency broadband sound fields is computationally intensive if determined on a frequency-by-frequency basis. Recently an energy-intensity boundary element method has been developed which employs uncorrelated broadband directional energy sources to predict expeditiously such pressure distributions. The source strength and directivity associated with the energy sources, distributed over enclosure boundaries, were determined in an iterative manner. Here, further refinement of the method is presented including the direct determination of source strength and directivity without iteration. Additionally, recent improvements allow for specifying the degree to which the reflected field is modeled as diffuse relative to specular for a given element. Good agreement between the improved energy–intensity boundary element method and experimental measurements and/or exact analytical solutions are shown. [Work sponsored by NSF.]
An expanded spherical wave expansion for arbitrary sound fields
Authors: Rayess Nassif E.
Published: October 2013

Spherical wave function expansions as means of describing the acoustic field radiated by arbitrarily shaped objects are very convenient and gaining popularity. The HELS method for acoustic holography is one methodology advocating the use of spherical wave functions as a basis for the solution of the inverse acoustic problem. Such methodologies only provide an approximation to the actual sound field and as such suffer from errors, albeit understood to be bounded and manageable in a large number of cases. Based on the sound radiation model of a volume distribution of monopole sources, these approximation errors are found to be due to the presence of monopole sources outside the largest inscribed virtual sphere. Monopole sources outside that virtual sphere are not accounted for in the expansion and thus come out as errors. These errors are greatly reduced if the spherical wave function expansion is modified to account for the largest number of monopole sources in the model. This is accomplished by employing the addition theorem for spherical harmonics. This modification complicates the problem mathematically and might require a greater rate of physical sampling, however the reduction in the reconstruction errors might prove beneficial.
The use of a waveguide expansion to model landmine detection using acoustic to seismic coupling
Authors: Velea Doru , Waxler Roger
Published: October 2013

The use of a waveguide of sufficiently large radius to simplify the modeling of the infinite space response of a buried landmine to airborne sound has been investigated. It was previously determined that if the ground is modeled as an effective fluid, an efficient and rapidly converging algorithm can be obtained. The effective fluid has been replaced with an elastic solid. For such a model, this technique fails to converge sufficiently rapidly to the infinite space limit. The surface wave supported by the shear sector gets excited by the landmine. The decay of this surface wave with distance is too slow, forcing one to use a waveguide of a prohibitively large radius. In conclusion, this technique at best gives qualitative results. [Work sponsored by the U.S. Army Communications–Electronics Command, Night Vision and Electronics Sensors Directorate.]
Ecological prognosis near intensive acoustic sources
Authors: Kostarev Stanislav A. , Makhortykh Sergey A. , Rybak Samuil A.
Published: October 2013

The problem of a wave field excitation in a ground from a quasi-periodic source, placed on the ground surface or at some depth in soil is investigated. The ecological situation in this case in many respects is determined by quality of the raised vibrations and noise forecast. In the present work the distributed source is modeled by the set of statistically linked compact sources on the surface or in the ground. Changes of parameters of the media along an axis and horizontal heterogeneity of environment are taken into account. Both analytical and numerical approaches are developed. The last are included in software package VibraCalc, allowing to calculate distribution of the elastic waves field in a ground from quasilinear sources. Accurate evaluation of vibration levels in buildings from high intensity under ground sources is fulfilled by modeling of the wave propagation in dissipative inhomogeneous elastic media. The model takes into account both bulk (longitudinal and shear) and surface Rayleigh waves. For the verification of used approach a series of measurements was carried out near the experimental part of monorail road designed in Moscow. Both calculation and measurements results are presented in the paper.
Perceptual overshoot with speech and nonspeech sounds
Authors: Aravamudhan Radhika , Hawks John. W.
Published: October 2013

One of the basic quests in speech perception research has been to find the differences or similarities in the mechanisms involved in the perception of speech and nonspeech sounds. The current study will address the differences in perception of speech and nonspeech signals by comparing the perceptual overshoot in synthetic vowels and sinewave acoustic replicas of the synthetic vowels. Lindblom and Studdert-Kennedy (1967) demonstrated that the perceptual boundary for steady state vowels and that for vowels in a CV context with F2 transition are different. They called this phenomenon a perceptual compensation or perceptual overshoot. In the current study the perceptual boundaries for synthetic steady state vowels, steady state sinewave acoustic replicas of vowels, a vowel in the CV context with F2 transition and sinewave acoustic replicas of vowels in the CV context are compared. The results will be discussed in the poster. For Speech Communication Best Student Paper Award.
The effects of regional dialect on vowel intelligibility from a cross-linguistic perspective
Authors: Frieda Elaina M. , Fox Robert A.
Published: October 2013

The present experiment is a continuation of a previously reported study that examined intelligibility of English vowels as a function of dialect spoken by native speakers of English and Japanese. The purpose of this research is to assess how regional dialectal variations affect vowel intelligibility for native and non-native speakers of English. Native English and Japanese subjects were recorded in two divergent dialectal regions of the United States (Ohio and Alabama). These tokens were then employed in a perceptual experiment where native English and Japanese listeners from Ohio and Alabama identified the English vowels. To date, perceptual data from only Ohio native English and Japanese subjects have been reported. A further analysis of the data including Alabama native English and Japanese listeners revealed that native English speakers from Ohio obtained the highest intelligibility scores overall (for example, all four listener groups identified Ohio English more accurately than all other groups). Additionally, native Japanese speakers from Alabama received the lowest overall intelligibility scores. The tentative results of this study imply that non-native speakers of English that are exposed to a nonstandard dialect may have deleterious effects on comprehension.
The representation of consonant clusters in the mental lexicon
Authors: Incognito Lisa J. , Sawusch James R.
Published: October 2013

Previous work has shown that the perception of a phoneme in a syllable is influenced by the number of similar sounding words [lexical neighborhood (Newman, Sawusch, and Luce, 1997)]. This previous work determined neighborhoods for target syllables using a one phoneme change rule. For example, bow, bath and mouth are neighbors of bowth. The present work focused on how consonant clusters are represented in the mental lexicon. Nonsense syllables composed of initial consonant clusters followed by a vowel and final consonant were used as stimuli. Two rules were used to compute the neighborhood for each target syllable. One was the one phoneme change rule used in previous studies. The second treated clusters of consonants as single units in a one unit change rule. Target syllables with differential neighborhoods based on the two rules were the endpoints of the test series. Results to date agree with the one phoneme change rule. These results are consistent with models of word recognition which treat consonant clusters as a sequence of phonemes. [Work supported by NIDCD Grant R01DC00219 to SUNY at Buffalo.]
Sonority contours in word recognition
Authors: McLennan Sean
Published: October 2013

Contrary to the Generativist distinction between competence and performance which asserts that speech or perception errors are due to random, nonlinguistic factors, it seems likely that errors are principled and possibly governed by some of the same constraints as language. A preliminary investigation of errors modeled after the child’s ‘‘Chain Whisper’’ game (a degraded stimulus task) suggests that a significant number of recognition errors can be characterized as an improvement in syllable sonority contour towards the linguistically least-marked, voiceless-stop-plus-vowel syllable. An independent study of sonority contours showed that approximately half of the English lexicon can be uniquely identified by their contour alone. Additionally, ‘‘sororities’’ (groups of words that share a single sonority contour), surprisingly, show no correlation to familiarity or frequency in either size or membership. Together these results imply that sonority contours may be an important factor in word recognition and in defining word ‘‘neighborhoods.’’ Moreover, they suggest that linguistic markedness constraints may be more prevalent in performance-related phenomena than previously accepted.
Children’s perception of static noise and static formant cues to stop-consonant place of articulation
Authors: Ohde Ralph N.
Published: October 2013

Children’s processing strategies appear to favor dynamic cues such as formant transitions as compared to static cues such as F2 onsets and noise bursts. The purpose of this research was to examine children’s perception of place of articulation based only on static cues. Ten children at each of five age levels (3, 4, 5, 6, and 7) and a control group of 10 adults identified synthesized stop consonants [d g] in two vowel contexts [i ɑ]. The synthesis parameters included variations in F2 onsets and stop-consonant noise bursts. The F2 onsets were either ‘‘appropriate’’ or ‘‘neutral’’ for place of articulation. The noise bursts were either short (10 ms) or long (25 ms). Preliminary data show that the F2 onset is not as salient in children’s perception as in adults’ perception. In addition, children more often than adults categorized neutral F2 onset stimuli as ambiguous indicating stronger category formation in the latter than former groups. The role of noise bursts was more salient in adult perception than child perception. The findings will provide information on the role of ‘‘static’’ cues, on the perceptual integration of ‘‘static’’ noise and formant cues, and on the influence of sound category formation in perceptual development. [Work supported by NIH and a Vanderbilt University Research Council Grant.]
Lip interactions and closure duration in labial consonants
Authors: Lofqvist Anders
Published: October 2013

This study examines interactions between the upper and lower lips in labial consonants where the duration of the oral closure is varied for linguistic purposes. Earlier work has shown that such interactions occur and that their magnitude is partly related to the duration of the oral closure. Lip movements were recorded in native Japanese speakers using a magnetometer system. Results show a positive correlation between the vertical positions of the upper and lower, when both are measured at the point in time where the lower lip reached its peak position during the oral closure. Since the peak vertical position of the lower lip increased with closure duration, the upper lip also had a higher vertical position at the same point in time for long than for short consonants. During the oral closure, the lower lip continued to move upward with a larger movement for long than for short consonants. Due to the mechanical interaction between the lips, the upper lip reversed its downward movement at the onset of the oral closure and also moved upward during the closure, again with a larger movement for long than for short consonants. [Work supported by NIH.]
When there is way too much stress: A first look at the failure behavior of vocal fold tissue
Authors: Chan Roger W. , Siegmund Thomas
Published: October 2013

In normal voice production, linear small-amplitude vocal fold oscillation occurs only under restricted conditions, such as during oscillation onset and offset. More often than not, phonation in physiological range involves large-amplitude oscillation that is associated with the development of tissue shear stresses and strains much beyond their linear viscoelastic limit, particularly in the vibrating portion of the vocal fold, i.e., the extracellular matrix (ECM). This study targeted one such large-strain nonlinear viscoelastic behavior of the vocal fold by attempting to quantify the stress failure response of the vocal fold ECM under shear. Sheep vocal fold ECM specimens were subjected to torsional, steady shear in a controlled-strain rheometer in vitro, at constant strain rates of 0.01, 0.1, and 1.0 rad/s. Results showed that the vocal fold ECM demonstrated nonlinear stress–strain response, as well as failure response when shear strain reached around 100%. Strain-dependent and rate-dependent onset of partial and complete stress failure was observed. A constitutive approach based on a standard-linear cohesive zone model was formulated to characterize the observed rate-dependent failure behavior of the vocal fold ECM. These findings have important implications for predicting tissue injury and for establishing stress and strain safety limits for large-amplitude vocal fold oscillation.
Effects of the age of cochlear implantation on the quality of the speech produced by profoundly HOH speakers
Authors: Lake Samantha , Kollia Betty
Published: October 2013

Four hearing-impaired children with prelingual, bilateral, severe-to-profound hearing loss were grouped by age, gender, and age at implantation; the younger group consisted of females approximately 6 years old and implanted between 1–2 years of age and the older group consisted of males approximately 14 years old and implanted at 9 years of age. Each child was diagnosed with prelingual hearing loss, was implanted with the Nucleus 24® cochlear implant in 1998, and has approximately 4 years of experience using the implant consistently. All subjects receive 8 h of direct instruction with the implant per week, in a school for the deaf that utilizes total communication. Each subject also receives speech therapy in 30-min sessions four times per week and exhibits intelligible speech. Coarticulation in the children’s speech was studied using five consonant-diphthong-consonant pseudowords, in the carrier sentence ‘‘it’s a —– again.’’ The recordings were digitized and analyzed acoustically. The results are discussed with reference to the age of cochlear implantation of the children and its role in the quality of their speech.
Open-source software for speech perception research
Authors: Gayvert Robert T. , Hillenbrand James M.
Published: October 2013

The purpose of this paper is to describe some relatively simple software that can be used for performing such routine tasks as controlling listening experiments (e.g., simple labeling, discrimination using procedures such as ABX, oddity, same–different, etc., sentence intelligibility, magnitude estimation, and so on), recording responses and response latencies, analyzing and plotting the results of those experiments, displaying instructions, and making scripted audio recordings. The software runs under Windows and is controlled by creating text files that allow the experimenter to specify key features of the experiment such as the stimuli that are to be presented, the randomization scheme, inter-stimulus and inter-trial intervals, the format of the output file, and the layout of response alternatives on the screen. Some simple demonstrations will be provided, along with instructions for downloading the software. [Work supported by NIH.]
Application of discrete wavelet transform to measurement of traffic using road environmental sound from microphone on vehicle
Authors: Hara Hironori , Ozawa Shinji
Published: October 2013

It is important for progress of ITS technology to develop the sensor that receives surrounding information and algorithm that extracts information. Recently the media generally used for ITS research is a picture, and not much research using sound is done. But sound sensor is still expected because sound has global information and less calculation cost than a picture. And research of a probe car that collects surrounding situations by the sensor is generally done. So improvement in sensing technology is desired. Moreover discrete wavelet transform attracts attention as the technique of signal processing. DWT is suitable for the analysis of nonstationary signals as road environmental sound. So the new system of the probe car using a sound sensor is proposed. Measurement of traffic is assumed as a probe car application example. In this paper, the result of count passing oncoming car with DWT to road environmental sound is reported. Road environmental sound was recorded in two kinds of road, uncovered road and tunnel, the validity of algorithm was verified by experiment.
Approaches to robustness
Authors: Cox Henry , Heaney Kevin D.
Published: October 2013

The term robustness in signal processing applications usually refers to approaches that are not degraded significantly when the assumptions that were invoked in defining the processing algorithm are no longer valid. Highly tuned algorithms that fall apart in real-world conditions are useless. The classic example is super-directive arrays of closely spaced elements. The very narrow beams and high directivity could be predicted under ideal conditions, could not be achieved under realistic conditions of amplitude, phase and position errors. The robust design tries to take into account the real environment as part of the optimization problem. This problem led to the introduction of the white noise gain constraint and diagonal loading in adaptive beam forming. Multiple linear constraints have been introduced in pursuit of robustness. Sonar systems such as towed arrays operate in less than ideal conditions, making robustness a concern. A special problem in sonar systems is failed array elements. This leads to severe degradation in beam patterns and bearing response patterns. Another robustness issue arises in matched field processing that uses an acoustic propagation model in the beamforming. Knowledge of the environmental parameters is usually limited. This paper reviews the various approaches to achieving robustness in sonar systems.
Mode excision adaptive beamforming for source detection in an uncertain shallow-water waveguide
Authors: Premus Vincent E.
Published: October 2013

Passive sonar detection is uniquely characterized by the fact that the acoustic clutter distribution is generally confined to the ocean’s surface. There is considerable evidence to support the hypothesis that surfaced and submerged sources are well separated in acoustic mode space, and that shallow-water waveguide normal modes are relatively robust to imperfect environmental knowledge. In this work, the use of mode physics is explored for the purpose of identifying an improved adaptive subspace for submerged source detection in the presence of surface interference. The basic premise is to perform adaptive weight computation in a mode subspace that is weakly excited by the submerged source of interest, yet well coupled to the surface interference. The rationale is to excise as much of the target signature as possible from the sample covariance without excessively compromising the measurement of the interference spatial spectrum. This enables more aggressive nulling of the surface clutter spectrum for a given level of signal gain degradation on the submerged source of interest. In this paper, the algorithm for adaptive mode subspace identification will be discussed, and the theoretical performance as a function of imprecise environmental knowledge and array calibration will be examined for a number of different apertures, including vertical line arrays, horizontal line arrays, and volumetric arrays. [Work sponsored in part by DARPA, under Air Force Contract No. F19628-00-C-0002. Opinions, interpretations, conclusions, and recommendations are those of the author and are not necessarily endorsed by the U.S. Air Force.]
Noise model beamforming
Authors: Frazier Catherine H. , Schurman Iman W. , Newhall Bruce K.
Published: October 2013

Adaptive beamformers are usually based on the premise that noise is stationary and Gaussian, and hence completely characterized by a covariance matrix. The standard approach then attempts to use measured data to estimate that covariance and form a set of beamformer weights that optimally rejects the estimated noise. This standard method may not be robust to mismatch between real noise and the noise estimate. In particular, low frequency passive sonar noise is usually nonstationary, owing primarily to the motion of the shipping noise sources. We investigate alternative robust noise models that allow for nonstationarity. One such model [W. A. Kuperman and F. Ingenito, J. Acoust. Soc. Am. 67, 1988–1996 (1980)] assumes a uniform probability distribution for surface noise sources. This produces an optimal beamformer that is robust in uniformly rejecting surface noise, no matter where sources occur on the ocean surface or how they move. The noise performance of this beamformer will be compared to standard adaptive approaches for array configurations proposed by ONR for the Acoustic Observatory Program. The high fidelity simulation model used for noise prediction includes nonstationary source motion and realistic range-dependent multipath propagation effects. [Work supported by DARPA.]
Matched-field processing with an L-shaped array
Authors: Orris Gregory J. , Nicholas Michael , Perkins John S.
Published: October 2013

Data was collected on a 64 element L-shaped Array deployed in two at-sea experiments: RDS-1 off the coast of Halifax, Nova Scotia during late September of 1997, and KWIX-98 off Key West, Florida in August of 1998. The L-shaped array was deployed in a configuration with 32 elements in the horizontal and 32 elements in the vertical. Environmental variability during both experiments proved to be extreme at times due to weather and prevailing currents, making processing with so-called ‘‘high-resolution’’ and multi-frequency matched-field processing difficult. It was observed that fully coherent spatial processing using robust linear methods offered only marginal improvement over treating each leg of the array separately and combining the results in an incoherent processor. Possible explanations for these results are explored along with approaches aimed at improving the system performance. [Work supported by ONR.]
Blind sound channel deconvolution via artificial time reversal
Authors: Sabra Karim G. , Dowling David R.
Published: October 2013

Signals that travel through a sound channel are typically distorted when they are received by a remote listener because of interference arising from multiple propagation paths. This presentation introduces a novel passive acoustic technique for blind deconvolution of broadband signals recorded on a vertical array in an unknown multipath sound channel. The technique, called artificial time reversal or ATR, is based on artificially backpropagating the signals measured at the array to their source location using a broadband Green’s function synthesized directly from the measurements. The technique exploits generic features of modal propagation in ocean sound channels to infer a phase relationship between the Green’s function and the signal. The technique allows sound-channel spread signals to be compressed to their original length. Computational examples employing a single source are presented and compared with results obtained from oceanic measurements made in May 1997 off the west coast of Italy [Hodgkiss et al., J. Acoust. Soc. Am. 105, 1597 (1999)]. The temporal correlation between an ATR-compressed signal and the original signal approaches 100% in the computational examples and reaches 90% for the oceanic data. Potential extension of this technique to multiple sources emitting simultaneously in the same frequency band is also presented. [Work supported by ONR; oceanic data provided by Dr. Song of SIO.]
Synergistic advances in diagnostic and therapeutic medical ultrasound
Authors: Lizzi Frederic L.
Published: October 2013

Significant advances are more fully exploiting ultrasound’s potential for noninvasive diagnosis and treatment. Therapeutic systems employ intense focused beams to thermally kill cancer cells in, e.g., prostate; to stop bleeding; and to treat specific diseases (e.g., glaucoma). Diagnostic ultrasound techniques can quantitatively image an increasingly broad spectrum of physical tissue attributes. An exciting aspect of this progress is the emerging synergy between these modalities. Advanced diagnostic techniques may contribute at several stages in therapy. For example, treatment planning for small ocular tumors uses 50-MHz, 3-D ultrasonic images with 0.05-mm resolution. Thermal simulations employ these images to evaluate desired and undesired effects using exposure stategies with specially designed treatment beams. Therapy beam positioning can use diagnostic elastography to sense tissue motion induced by radiation pressure from high-intensity treatment beams. Therapy monitoring can sense lesion formation using elastography motion sensing (to detect the increased stiffness in lesions); harmonic imaging (to sense altered nonlinear properties); and spectrum analysis images (depicting changes in the sizes, concentration, and configuration of sub-resolution structures.) Experience from these applications will greatly expand the knowledge of acoustic phenomena in living tissues and should lead to further advances in medical ultrasound.