bluuebunny/crossref_metadata_2025 huggingface dataset:
Discrimination of synthetic /ba-wa/ by budgerigars (Melopsittacus undulatus)
Authors: Dent Michael L. , Powell Elizabeth F. , Pierce Alisa , Dooling Robert J.
Published: October 2005

The perception of speech sounds by animals provides important comparative data for understanding the perception of speech by humans. Using operant conditioning procedures, three budgerigars (Melopsittacusundulatus) were trained and then tested on their ability to discriminate among tokens of synthetic /ba-wa/ speech continua. A ‘‘short’’ (120 ms) and a ‘‘long’’ (320 ms) continuum were constructed, each consisting of 10 stimuli. For both the long and the short /ba-wa/ stimuli, budgerigars showed a marked improvement in discrimination near the human phonetic boundary. Similar to humans, budgerigars were significantly less sensitive to transition changes in the long syllables compared with the short syllables, suggesting that they may be susceptible to backward masking by the syllable of longer length. Two of the three budgerigars also showed a shift in their phonetic boundaries with changes in syllable length. These data extend the evidence of similarities between birds and mammals in the perception of speech sound contrasts. [Work supported by NIH Grants DC00198 and MH00982 to RJD.]
Measurement for measurement’s sake: Phonologically irrelevant stop voicing durations
Authors: Lisker Leigh
Published: October 2005

Durational differences between voiced and voiceless stops have been regularly reported, and phonological value has been attributed to some of them, i.e., VOT, closure duration (CD), and voicing-gap duration (VGD). Thus English /p,t,k/ and /b,d,g/ can sometimes be separated by all three measures, and these are then acoustico-articulatory properties of the voicing feature. But VOT also separates subphonemic (allophonic) variants of /p,t,k/ aspirated [ph, th, kh] and unaspirated [p,t,k], and it is customary to regard this difference as phonologically irrelevant. Furthermore, CD cues voicing state only when accompanied by a voicing gap, when a short VGD is effectively (perceptually?) equivalent to one of zero duration, so the voicing gap may be ‘‘dismissed’’ as a consequence of pressure equalization rather than a linguistically motivated laryngeal maneuver. Elsewhere the value of CD is more prosodic (moraic) than segment-identifying, distinguishing, e.g., Weplaydominoes. from Weplayeddominoes. Moreover, some VOT, CD, and VGD differences have little linguistic or even perception function. Thus /p,t,k/ show durational differences, but these cannot readily be shown to affect stop place perception. [Work supported by NIH Grant No. HD-01994.]
Eigenstatistics in rectangular membranes with point scatterers
Authors: Weaver Richard L.
Published: October 2005

Conventional wisdom holds that a finite reverberant system with chaotic ray trajectories will have, at high frequencies, eigenvalue statistics identical to those of the Gaussian orthogonal ensemble of random matrices (GOE). It also holds that a nonchaotic system will have simple Poissonian statistics. Recent experiments on the eigenvalues of elastic blocks with angled cuts, recent calculations of the eigenfrequencies of membranes with staircases like jagged boundaries and the eigenfrequencies of a rectangular domain with a single isotropic point scatterer have, however, found GOE statistics even in these quasi-integrable systems—even though all rays in such systems are nonchaotic. In this work the rectangular domain with isotropic point scatterers is studied further. It is shown that the long-range level repulsion in this system is not in precise accord with the predictions of the GOE, nor is the long range spectral rigidity. GOE does, though, correctly describe the short range statistics. A quantitative prediction for the range in which GOE applies is advanced based upon the lifetime of a ray against mixing—i.e., based upon the cross section of the scatterer. This prediction is corroborated by numerical calculations of the eigenfrequencies. [Work supported by NSF.]
Pure-tone thresholds and cubic distortion product otoacoustic emissions in the chinchilla following carboplatin treatment
Authors: Jock Brenda M. , Petriello Kristen-Lyn , Aldrich Lori G. , Johnson Ann R. , Hamernik Roger P. , Ahroon William A.
Published: October 2005

In the chinchilla, carboplatin has an unusual ototoxic effect on the sensory epithelium of the cochlea [Takono etal., Hear. Res. 75, 93–102 (1994)]. Twelve chinchillas were treated with a single IP or IV injection (50 or 75 mg/kg) of carboplatin. Baseline auditory evoked potential audiograms and cubic distortion product otoacoustic emissions (3DPE) were obtained on each animal. Threshold and 3DPE functions were also acquired at regular intervals between one hour and 30 days post-injection. The sensory epithelium of the cochlea was evaluated using the surface preparation method. Anatomical analysis indicated that the carboplatin caused relatively severe but scattered losses of inner hair cells (IHC) throughout most of the cochlea. The outer sensory cell population was intact and the cells appeared normal at the level of the light microscope. Despite the IHC pathology, which also included vacuolization in the area of the IHCs, evoked potential thresholds, measured at the level of the inferior colliculus were very near normal and 3DPE functions showed very little change. [Work supported by Bristol-Myers Oncology Division and SUNY-Plattsburgh.]
Flow resistance of fibrous materials
Authors: Tarnow Viggo
Published: October 2005

It is of interest to be able to compute the acoustical properties of fibrous materials from the fiber density and thickness of materials such as glass wool. These properties are mainly determined by the air flow resistance of the fibrous material. Theoretical calculations of air flow resistance will be presented and compared with measurements on glass wool.
Spiked volleyballs, dribbled basketballs, and kicked footballs: Excitation of the fundamental breathing mode in inflated sport balls
Authors: Browning David G. , Mellen Robert H. , Schneck Robert J. , Milbradt Stephanie
Published: October 2005

The analyses of the sound from a hand-struck or ‘‘spiked’’ volleyball, a ‘‘dribbled’’ basketball, and a place-kicked football show that in each case the fundamental ‘‘breathing’’ vibrational mode is excited in these inflated sport balls. Under regulation conditions the resonant frequency of a volleyball was found to be approximately 150 Hz; a basketball, which is larger but has a higher inflation pressure, was found to have a slightly higher frequency. Due to the shell material these vibrations are quickly damped. The results support the theoretical work [P. M. Morse and H. Feshbach, MethodsofTheoreticalPhysics (McGraw-Hill, New York, 1953), p. 1469] for a hollow, flexible sphere. It was found that ‘‘good’’ hits strongly excite this mode, ‘‘poor’’ ones do not. Acoustic analysis may be an important tool in determining optimum performance.
Fletcher’s contributions to loudness measurement and theory
Authors: Hellman Rhona P.
Published: October 2005

More than 70 years ago, Fletcher and his colleagues at Bell Telephone Laboratories initiated the first comprehensive investigations of loudness. Fletcher recognized that to improve the quality and efficiency of speech communication systems, one must know how the ultimate receiver, the human auditory system, processes and perceives sound. In his pioneering loudness studies, Fletcher devised innovative techniques for the measurement of loudness, uncovered the key parameters that modify loudness, and developed a model relating loudness to basic properties of the hearing mechanism. The achievements of Fletcher and his group demonstrated that loudness measurements can disclose (1) the relation between the spectral selectivity of hearing and sound intensity, (2) the effects of masking on loudness, (3) the principles of loudness additivity, (4) the dependence of loudness on spectral bandwidth, as well as (5) the functional integrity of the auditory system. These seminal discoveries not only inspired subsequent loudness studies, they also provided the empirical and theoretical foundation of contemporary loudness research and models. [Work supported in part by NIH Grant RO1 DC00084-18.]
A computer model for simulation of undersea noise from marine mammals
Authors: Hayward Thomas J. , Heitmeyer Richard M.
Published: October 2005

A computer model for the simulation of the spatial and temporal distribution of acoustic signals generated by marine mammals is presented. The model incorporates information from existing references on the geographic distribution of marine mammal species. Spatial distributions of individuals of each species that may be present at a site are generated using a random point process model that incorporates a statistical representation of the spatial clustering characteristics of each species. Individual vocalizations for each species are simulated by randomly selecting sampled acoustic source signatures from either the Woods Hole Oceanographic Institution’s SOUND database or from the NRL Dual Use Acoustics Center (DUAC) database. The acoustic source signatures are generated in random time patterns that emulate known vocalization repetition characteristics for each species. Sound propagation effects are incorporated by generating acoustic transfer functions using propagation models appropriate to the frequency band of each acoustic signature. The potential use of the model in the validation of marine mammal acoustic survey techniques is discussed. [Work supported by ONR.]
Talker variability and token variability in spoken word recognition: Effects on repetition priming in lexical decision and an explicit recognition memory task
Authors: Lyons Emily A.
Published: October 2005

Recent research (e.g., Goldinger, 1993) has suggested that representations of spoken words in memory may be veridical exemplars that encode instance-specific information, such as characteristics of the talker’s voice. This account of spoken word recognition was examined in work presented at a recent meeting of the Acoustical Society (Luce and Lyons, 1994). Evidence was presented in support of the claim that exemplar-type representations are used in explicit recognition memory tasks, but that more abstract representations play a role in tasks such as lexical decision. However, the previous work did not make clear the explicitness of the information encoded in exemplar-type representations; specifically whether only gross factors such as talker variation are encoded, or whether within speaker variation is also encoded. The present research expands on these previous results by comparing the effects of talker variation and same-speaker token variation on a repetition priming and an explicit recognition memory task. [Work supported by NIDCD.]
Vorticity characteristics of the vibration intensity field and the structure-borne sound
Authors: Tanaka Nobuo
Published: October 2005

This paper deals with the characteristics of real vibrational power flow in a simply supported rectangular panel under the action of feedforward vibration control. It is found that the path of the power flow is a combination of translations and rotations, the rotations induced by the interference of two modes which products a ‘‘vortex generating block.’’ Particular emphasis is placed on the vortex power flow in the vibration intensity field. A qualitative formula for predicting the number of power flow vortices, as well as the discussion of the vortex period, is put forward. Then, by introducing an energy stream function, the generation mechanism of the vortex power flow is quantitatively discussed. The fundamental characteristics of the vortex power flow are further clarified by vortex function derived from the intensity field. A novel method to induce a vortex at an arbitrary location of the plate is also shown, which may have practical applications in controlling the path of vibrational power flow in systems of large extent. Moreover, the influence of the induced vortex power flow on the plate onto the acoustic intensity distribution is investigated, showing that the rotational direction of the vortex on the plate is not always the same with that of the acoustic intensity in the nearfield.
Speechreading aids based on automatic speech recognition: Prospects for the automatic generation of cued speech
Authors: Braida L. D. , Uchanski R. M. , Delhorne L. A.
Published: October 2005

Current progress in the development of automatic speech recognition (ASR) systems may soon permit discrete symbolic speechreading supplements to be derived from the speech signal. Such supplements could be similar to those used in manual cued speech, in which the talker uses discrete hand positions and shapes to provide distinctions between constants and vowels that are often confused in speechreading. Highly trained receivers of manual cued speech can achieve nearly perfect reception of everyday connected speech materials at normal speaking rates through the visual sense alone. To understand the accuracy that might be achieved with automatically generated cues, we measured how well trained spectrogram readers and an automatic speech recognizer could assign cues for various cue systems. A model of audiovisual integration was then applied to these measurements and data on human recognition of consonant and vowel segments via speechreading was published. This analysis suggests that with cues derived from current recognizers, consonant and vowel segments can be received with accuracies in excess of 80%, roughly equivalent to the segment reception accuracy required to account for observed levels of manual cued speech reception. To provide guidance for the development of automatic cueing systems, we describe techniques for determining optimum cue groups for a given recognizer and speechreader, and estimate the cueing performance that might be achieved if the performance of current recognizers were improved.
The effect of multichannel dynamic compression on speech intelligibility
Authors: Hohmann Volker , Kollmeier Birger
Published: October 2005

In the recent literature on dynamic compression in hearing aids, a controversial discussion about the benefit of multichannel compression with short time constants has been raised. In this paper, some experimental results are contributed to the discussion: For low signal-to-noise ratios, a detrimental effect of fast multichannel compression on speech intelligibility in normal hearing listeners is found. However, a distinct degradation in speech quality and virtually no decrease in speech intelligibility is observed for comparatively high signal-to-noise ratios and compression ratios of up to 3. Since the predictions of the Speech Transmission Index deviate substantially from these results, its applications as an objective measure of intelligibility may not be extended to compressed speech.
Multichannel compression hearing aids: Effect of number of channels on speech discrimination in noise
Authors: Yund E. William , Buckles Krista M.
Published: October 2005

Full-range multichannel compression hearing aids (MCCHAs) with 4, 6, 8, 12, and 16 independent frequency channels were used to determine the effect of the number of channels on the speech discrimination of mild to moderately severe hearing-impaired subjects. Signal-to-noise ratios (S/Ns) from −5 to 15 dB with speech-spectrum noise (70 dB SPL) and two voices (male and female) were used. Average speech discrimination for 16 hearing-impaired subjects increased from 4 to 8 channels but did not change significantly between 8 and 16 channels. The effect of the number of channels did not vary significantly with S/N. Analyses of speech discrimination performance within phonemic categories as well as consonant-confusion analyses revealed response shifts with the number of channels that were consistent with increasing transmission of useful high-frequency speech information as the number of channels increased. These results indicate that a MCCHA with at least 8 (and up to 16) channels provides the mild to moderately severe hearing-impaired subject with acoustic information that facilitates speech discrimination in speech-band noise.
Transport of energy across a discontinuity by fluid loading
Authors: Photiadis Douglas M.
Published: October 2005

Short-circuiting effects due to fluid loading have been investigated for a plane flexural wave obliquely incident upon a line discontinuity in an elastic plate. General expressions for the transmission and reflection coefficients have been derived and exact analytical formulas are given for the required Green’s functions. The transmission coefficient resulting from the fluid loading has been evaluated and found to have a strong, step-function-like angular dependence vanishing at large angles of incidence. In addition, the near-field pressure and velocity fields have been numerically computed to directly examine the energetics of the transmission process. Transmission due to the fluid has been found to arise from propagating acoustic fields that must carry energy a distance of the order of a flexural wavelength. Accordingly, for angles greater than the critical angle, sin θc=k0/ks, transmission due to the fluid is strongly suppressed due to phase cancellation along the line discontinuity, thus explaining the angular dependence of the transmission coefficient.
Vortex sound theory: Direct proof of equivalence of ‘‘vortex force’’ and ‘‘vorticity-alone’’ formulations
Authors: Powell Alan
Published: October 2005

In the theory of vortex sound the far-field compact source strengths are the volume integrals of the time differential of the vortex force=−ρ(ζΛu)′, [ρ=(constant) fluid density, u=flow velocity, ζ=∇Λu=vorticity, ( )′≡∂( )/∂t], for dipole sound and of yx(ζΛu)x″ for quadrupole sound (y=local coordinate, yx=y⋅x/x with x=far-field observation point). Möhring’s method, using a vector Green’s function, produces instead the vorticity-alone volume integrals of 1/2(yΛζ)″ and of 1/3yx(yΛζ)x‴, respectively, that do not explicitly involve the velocity of the inviscid incompressible sound-generating flow. For two-dimensional flows, the corresponding integrands can be written as (ζΛu) and yx(ζΛu)x′ in the former formulation, and (yΛζ)′ and 1/2yx(yΛζ)x″ in the latter. Direct proofs that these different integral results are in fact exactly equal to each other are offered: Given one form, the other can be found with no appeal to acoustical theory whatsoever. However, the integrands are not equal, and while −ρ(ζΛu)′ can be interpreted uniquely as the dipole strength per unit volume, this is not so for ρ(yΛζ)x″. The implications of these integral formulations is discussed.
Phase effects in masking related to dispersion in the inner ear. II. Masking period patterns of short targets
Authors: Kohlrausch Armin , Sander Andres
Published: October 2005

This article investigates how the amplitude and phase characteristics of the inner ear influence the spectrotemporal representation of harmonic complex sounds. Five experiments are reported, in each of which three sets of maskers are compared that differ only in their phase spectra. The amplitude spectra of the complexes were flat and the phase choices were (a) zero phase, (b) Schroeder phases with a positive sign, and (c) Schroeder phases with a negative sign. In the first four experiments, the spectra contained all harmonics between 200 and 2000 Hz. In experiments 1 and 2, the signal frequency was fixed at 1100 Hz and the fundamental frequency of the maskers was varied. In experiments 3 and 4, the fundamental frequency of the maskers was fixed and the signal frequency varied between 200 and 2000 Hz. In experiments 1 and 3, the signal duration was long compared to the period of the maskers. In experiments 2 and 4, the signal duration was only 5 ms and thresholds were determined for different time points within the masker’s period. The results show a strong correlation between the minima of the short signal’s thresholds and the threshold of the long signal. In experiment 5, the spectral extent of the masker was shifted to values one octave lower (100 to 1000 Hz) or one or two octaves higher (400 to 4000 Hz and 800 to 8000 Hz, respectively). For each spectral region, masked thresholds of a long signal were obtained for three values of the fundamental frequency.

In all five experiments the thresholds depended very much on the specific phase choices with differences of up to 25 dB. The masker with a negative Schroeder phase always led to the highest thresholds. The thresholds of the masker with a positive Schroeder phase, on the other hand, were for a wide range of parameters lower than the thresholds for the zero-phase masker. These phase effects are most likely caused by the phase characteristic of the basilar-membrane filter, which affects the flat envelopes of the two Schroeder-phase maskers in a very different way. For an appropriate choice of parameters, one of the two becomes even more strongly modulated than the zero-phase complex. This latter observation imposes some restrictions on the second derivative (curvature) of the phase-versus-frequency relation for the auditory filters.
Influence of backing compliance on transducer performance
Authors: Corsaro Robert D. , Young Rose M.
Published: October 2005

This paper presents a simple one-dimensional model for describing the influence of backing impedance on the performance of sensors and projectors. It uses a center-of-mass model, where the influence of backing can be largely extracted into a separable term. As an example, it includes consideration of the familiar underwater case of an air-backed steel plate with an outer compliant (decoupler) coating. This approach is principally useful in large numerical structural acoustical studies, where the use of complete transducer formulations would become computationally impractical.
Perceptual organization in a comodulation masking release interference paradigm: Exploring the role of amplitude modulation, frequency modulation, and harmonicity
Authors: Grose John H. , Hall Joseph W. , Mendoza Lee
Published: October 2005

Two areas of interest within auditory scene analysis are the identification of cues which contribute to auditory grouping and/or segregation, and the methodology employed to measure such effects. The present study explored the roles of three purported grouping cues—correlated AM, correlated FM, and harmonicity—using a comodulation masking release interference paradigm. This method was reasoned to be free of alterations in the subject’s mode of listening (analytic versus synthetic). The results suggested that correlated AM was a viable grouping cue. For some listeners, the presence of FM also appeared to provide a grouping cue, but, generally, no effect of coherence of FM was observed. No effect of harmonicity was observed in this paradigm.
Thresholds for formant-frequency discrimination of vowels in consonantal context
Authors: Kewley-Port Diane
Published: October 2005

Thresholds for formant frequency discrimination were shown to be in the range of 1%–2% by Kewley-Port and Watson [J. Acoust. Soc. Am. 95, 485–496 (1994)]. The present experiment extends that study and one by Mermelstein [J. Acoust. Soc. Am. 63, 572–580 (1978)] to determine the effect of consonantal context on the discrimination of formant frequency. Thresholds for formant frequency were measured under minimal stimulus uncertainty for the vowel /i/ synthesized in isolation and in CVC syllables with the consonants /b/, /d/, /g/, /z/, /m/, and /l/. Overall, the effects of consonantal context were similar to those reported by Mermelstein (1978), although his threshold estimates were a factor of 4–5 times larger because less-than-optimal psychophysical methods had been used. Compared to the vowel in isolation, consonantal context had little effect on thresholds for F1 and a larger effect on F2. When a shift in threshold was observed, subject variability was high and resolution was degraded by as much as a factor of 2. Analyses of stimulus parameters indicated that resolution was degraded by shortening steady-state vowel duration or if the separation between the onsets of the formant transitions was small. Overall, consonantal context makes it more difficult for some, but not all, listeners to resolve formant frequency as accurately as for vowels in isolation.
Acoustic measurements of scattering by objects of irregular shape
Authors: Thorne Peter D. , Waters Kendall R. , Brudner Terry J.
Published: October 2005

Although many scatterers in nature are irregular in shape, the data on the scattering of sound by asymmetrical bodies is relatively limited. Our understanding of the scattering of underwater sound by nonregular shaped targets is therefore significantly less developed than that due to scattering by scatterers of symmetry. In the present work, measurements are reported on the backscattering from irregularly shaped solid elastic particles in both the time and frequency domains. Backscatter data have been collected for a variety of irregularly shaped particles at varying orientations. These observations show a number of characteristics which are comparable with scattering by targets of symmetry, particularly the property of the scattered echo being significantly longer in duration than the insonifying pulse. This pulse elongation for symmetrical targets is normally interpreted using resonance scattering theory, RST, as arising from radiation due to surface eigen waves on the body of the scatterer. In the present work the interpretation of the scattering by irregular shaped targets has been guided by resonance scattering studies, and an understanding of the response formulated within this framework.
A spatial feature extraction and regularization model for the head-related transfer function
Authors: Chen Jiashu , Van Veen Barry D. , Hecox Kurt E.
Published: October 2005

A functional representation is proposed for complex valued (amplitude and phase) head-related transfer functions (HRTFs), including both frequency and spatial dependence. The frequency variation is spanned by a set of eigentransfer functions (EFs) that are generated using the Karhunen–Loève expansion. Any HRTF is represented as a weighted combination of the EFs where the weights are functions of the HRTFs spatial location and are termed spatial characteristic functions (SCFs). Samples of the SCFs are obtained by projecting the measured HRTFs onto the EFs. A regularization framework is employed to obtain a functional representation for the SCFs by fitting each set of SCF samples with a two-dimensional spline. Acoustic validation of the model’s fidelity and predictive capability is provided using 2188 measured HRTFs from a KEMAR manikin and 1816 measured HRTFs from an anesthetized live cat. Errors between measured and modeled HRTFs are generally less than one percent. Larger errors occur in the contralateral regions for KEMAR and lower back regions for the cat as a consequence of the relatively small HRTF amplitudes resulting from head shadowing. Methods for reducing these errors are discussed.
Temporal envelope and fine structure cues for speech intelligibility
Authors: Drullman Rob
Published: October 2005

This paper describes a number of listening experiments to investigate the relative contribution of temporal envelope modulations and fine structure to speech intelligibility. The amplitude envelopes of 24 1/4-oct bands (covering 100–6400 Hz) were processed in several ways (e.g., fast compression) in order to assess the importance of the modulation peaks and troughs. Results for 60 normal-hearing subjects show that reduction of modulations by the addition of noise is more detrimental to sentence intelligibility than the same degree of reduction achieved by direct manipulation of the envelope; in some cases the benefit in speech-reception threshold (SRT) is almost 7 dB. Two crossover levels can be defined in dividing the temporal envelope into two equally important parts. The first crossover level divides the envelope into two perceptually equal parts: Removing modulations either x dB below or above that level yields the same intelligibility score. The second crossover level divides the envelope into two acoustically equal peak and trough parts. The perceptual level is 9–12 dB higher than the acoustic level, indicating that envelope peaks are perceptually more important than troughs. Further results showed that 24 intact temporal speech envelopes with noise fine structure retain perfect intelligibility. In general, for the present type of signal manipulations, no one-to-one relation between the modulation-transfer function and the intelligibility scores could be established.
Applications of the combustive sound source
Authors: Wilson Preston S. , Muir Thomas G. , Behrens John A. , Elizey Janet L.
Published: October 2005

The combustive sound source (CSS) can be used to generate high-intensity, low-frequency acoustic energy in a variety of mediums by using deployment configurations suitable to each medium. The basic principle of operation remains configuration independent. A gaseous fuel/oxidizer mixture is introduced into a combustion chamber and ignited with a spark. The ensuing combustion produces a bubble of expanding gas which, in turn produces high-intensity, low-frequency acoustic pulses. Three different deployment configuration experiments will be discussed, including water column, ocean-bottom seismic, and earth-surface seismic. In-situ measured energy levels and spectra produced by CSS are compared to other sources typical to each medium, including explosive and inertial. It is shown that CSS is capable of producing bulk waves in both water and earth mediums, as well as seismic interface waves for both air/earth and water/sea floor cases. It is demonstrated that CSS is a truly versatile acoustic energy source with a low cost deployment configuration which can be tailored easily to different environments. [Work supported by the U.S. Navy Office of Naval Research.]
Flow-induced sound
Authors: Powell Alan
Published: October 2005

After a brief historical account introducing some lasting concepts, the origins and main features of aerodynamically generated sound are described in terms of the melding of some pertinent elements of fluid dynamics and of acoustics. These are, for example, flow separation, flow instability, and vortices on the one hand, coupled with the hydrodynamic flows of acoustic monopoles, dipoles, and quadrupoles on the other. With emphasis on the vortex theory of aerodynamic sound, various theoretical approaches are generally described in physical terms and are illustrated by a variety of sound-generating flows. These may be classified as free flows with no solid surfaces present (spinning vortices, turbulent jet noise, supersonic jet screech), flows over rigid surfaces (boundary layer noise, whistling telephone wires, edge tones, pipe tones, vocal fricatives, and whistling, organ pipes), interaction with steadily moving surfaces (helicopter blade slap, fan blade interaction, but not including the rotational noise of fans and propellers), flow with excited surfaces (interior aircraft boundary layer noise, aeolian tones, reed and lip-driven musical instruments, vocal chord vibration, snoring and raspberries). Some of these involved no resonance at all, while others have flow resonance, acoustic resonance or mechanical vibration or resonance.
A model of nonlinear behavior of ice cracks
Authors: Ostrovsky Lev A. , Ekimov Alexander E. , Lebedev Andrey V. , Sutin Alexander M.
Published: October 2005

A work presented at the previous ASA meeting has demonstrated that the cracks may provide anomalously strong vibroacoustic nonlinearity in ice. Experimental data were obtained from the field experiments on a fresh-water lake, where a strong subharmonic signal was, in particular, registered. Here, a theoretical model is suggested for the description of the effects observed and possible use of them for characterizing the crack parameters. The model is based on consideration of nonlinear flexural oscillations of the ice plate with a crack which may be ‘‘opened’’ from its upper or lower part due to flexural oscillations. Together with the added mass of the surrounding area of the plate, a nonlinear oscillator may be formed which admits both higher harmonic and subharmonic generation (a parametric effect). The oscillator has a strong nonlinearity and relatively low Q factor which may provide a possibility of parametric excitation if there is a rather wide frequency range. The model considered seems to be applicable for real sea conditions.
Effects of low-frequency underwater sound on hair cells of the inner ear and lateral line of the teleost fish Astronotus ocellatus
Authors: Hastings Mardi C. , Popper Arthur N. , Finneran James J. , Lanford Pamela J.
Published: October 2005

Fish (Astronotus ocellatus, the oscar) were subject to pure tones in order to determine the effects of sound at levels typical of man-made sources on the sensory epithelia of the ear and the lateral line. Sounds varied in frequency (60 or 300 Hz), duty cycle (20% or continuous), and intensity (100, 140, or 180 dB re: 1 μPa). Fish were allowed to survive for 1 or 4 days posttreatment. Tissue was then evaluated using scanning electron microscopy to assess the presence or absence of ciliary bundles on the sensory hair cells on each of the otic endorgans and the lateral line. The only damage that was observed was in four of five fish stimulated with 300-Hz continuous tones at 180 dB re: 1 μPa and allowed to survive for 4 days. Damage was limited to small regions of the striola of the utricle and lagena. There was no damage in any other endorgan, and the size and location of the damage varied between specimens. No damage was observed in fish that had been allowed to survive for 1 day poststimulation, suggesting that damage may develop slowly after exposure.
Analysis of the numerically implemented angular spectrum approach based on the evaluation of two-dimensional acoustic fields. Part I. Errors due to the discrete Fourier transform and discretization
Authors: Wu Ping , Kazys Rymantas , Stepinski Tadeusz
Published: October 2005

The numerically implemented angular spectrum approach (ASA) is investigated based on the evaluation of the 2-D fields radiated by striplike planar sources and 1-D focusing linear-phased arrays with different aperture sizes and on the comparison with those obtained by using the analytical solution derived with the point spread function method. Since the discrete Fourier transform (DFT) of a finite-size source produces an angular spectrum with spatial frequency aliasing and discretization of the source in even-numbered samples causes a half-sample length phase shift error in the angular spectrum, the effects of the aliasing and the phase shift on calculation accuracy are dealt with. The results show that the frequency aliasing causes an overestimation of the near field and the phase shift distorts the results. A numerical algorithm for eliminating the aliasing is proposed and correction of the phase shift is confirmed to be necessary. The algorithm proposed can completely remove the errors and obtain exact results. The methods used in this paper can be directly applied to the case of 3-D fields. The investigation of the characteristics of the numerically implemented ASA as a function of angular range is carried out in the companion paper [P. Wu, R. Kazys, and T. Stepinski, ‘‘Analysis of the numerically implemented angular spectrum approach based on the evaluation of two-dimensional acoustic fields. Part II. Characteristics as a function of angular range,’’ J. Acoust. Soc. Am. 99, 1349–1359 (1996)].
Theoretical model to describe dispersive nonlinear properties of lead zirconate–titanate ceramics
Authors: Van Den Abeele K. , Breazeale M. A.
Published: October 2005

Frequency dependence of the first ultrasonic nonlinear parameter and the abnormally high third harmonic signals measured in lead zirconate–titanate (PZT) ceramics suggest the introduction of a revised theoretical model combining higher-order nonlinearity and generalized dispersion. The new nonlinear dispersive equation has been solved by perturbation theory. A solution is found in the form of a set of parameters whose magnitude is obtained from a fit of the experimental data. The parameters are independent of frequency and initial amplitude. The model is applied to four samples, and the results are discussed. The validity of the perturbation theory in these cases is tested.
Stimulus features affecting psychophysical detection thresholds for electrical stimulation of the cochlea. III. Pulse polarity
Authors: Coste Rebecca L. , Pfingst Bryan E.
Published: October 2005

Effects of initial-phase polarity on psychophysical detection thresholds for electrical stimulation of the cochlea were examined in four nonhuman primates using trains of biphasic and triphasic charge-balanced pulses. Initial-phase polarity had small but consistent effects on the levels and slopes of threshold versus phase duration functions. These effects were consistent with the hypothesis that the initial-phase polarity affects the site of action potential initiation. Thresholds for biphasic pulses were lower than those for triphasic pulses, suggesting that the system is responsive to both positive and negative phases of the stimulus. Interactions between initial-phase polarity, pulse waveform, and phase duration were observed.
Sources and effects of low-frequency noise
Authors: Berglund Birgitta , Hassmén Peter , Job R. F. Soames
Published: October 2005

The sources of human exposure to low-frequency noise and its effects are reviewed. Low-frequency noise is common as background noise in urban environments, and as an emission from many artificial sources: road vehicles, aircraft, industrial machinery, artillery and mining explosions, and air movement machinery including wind turbines, compressors, and ventilation or air-conditioning units. The effects of low-frequency noise are of particular concern because of its pervasiveness due to numerous sources, efficient propagation, and reduced efficacy of many structures (dwellings, walls, and hearing protection) in attenuating low-frequency noise compared with other noise. Intense low-frequency noise appears to produce clear symptoms including respiratory impairment and aural pain. Although the effects of lower intensities of low-frequency noise are difficult to establish for methodological reasons, evidence suggests that a number of adverse effects of noise in general arise from exposure to low-frequency noise: Loudness judgments and annoyance reactions are sometimes reported to be greater for low-frequency noise than other noises for equal sound-pressure level; annoyance is exacerbated by rattle or vibration induced by low-frequency noise; speech intelligibility may be reduced more by low-frequency noise than other noises except those in the frequency range of speech itself, because of the upward spread of masking. On the other hand, it is also possible that low-frequency noise provides some protection against the effects of simultaneous higher frequency noise on hearing. Research needs and policy decisions, based on what is currently known, are considered.
The ipsilaterally evoked olivocochlear reflex causes rapid adaptation of the 2 f1−f2 distortion product otoacoustic emission
Authors: Liberman M. C. , Puria Sunil , Guinan, J. J.
Published: October 2005

The onset behavior of the distortion product otoacoustic emission (DPOAE) at 2 f1−f2 in anesthetized cats was measured with temporal resolution finer than 70 ms. The amplitude of the DPOAE adapts after onset of the primary tones by as much as 6 dB for monaural stimulation and 10 dB when the primaries are presented binaurally. DPOAE adaptation consists of a large, rapid component, with a time constant of roughly 100 ms, and a small, slower component with a time constant of roughly 1000 ms. The rapid component disappears when only the crossed olivocochlear bundle (OCB) is cut, whereas the slow adaptation persists after complete OCB section. The loss of rapid adaptation upon OC section is accompanied by a concomitant increase in the steady-state amplitude of the DPOAE. Thus an intact OC reflex can significantly alter DPOAEs obtained during routine measurement. Rapid adaptation of the monaurally evoked 2 f1−f2 DPOAE is probably mediated by reflex activity in ipsilaterally responsive OC neurons innervating outer hair cells. The effects of this ipsilateral reflex on DPOAE amplitudes are typically twice as large as those of the contralateral reflex, presumably because there are twice as many ipsilaterally responsive OC neurons. Tests for the ipsilateral OC reflex based on the phenomenon of rapid adaptation should be both feasible and useful in human subjects.
Time-domain modeling of finite-amplitude sound in relaxing fluids
Authors: Cleveland Robin O. , Hamilton Mark F. , Blackstock David T.
Published: October 2005

A time-domain computer algorithm that solves an augmented Burgers equation is described. The algorithm is a modification of the time-domain code developed by Lee and Hamilton [J. Acoust. Soc. Am. 97, 906–917 (1995)] for pulsed finite-amplitude sound beams in homogeneous, thermoviscous fluids. In the present paper, effects of nonlinearity, absorption and dispersion (both thermoviscous and relaxational), geometrical spreading, and inhomogeneity of the medium are taken into account. The novel feature of the code is that effects of absorption and dispersion due to multiple relaxation phenomena are included with calculations performed exclusively in the time domain. Numerical results are compared with an analytic solution for a plane step shock in a monorelaxing fluid, and with frequency-domain calculations for a plane harmonic wave in a thermoviscous, monorelaxing fluid. The algorithm is also used to solve an augmented KZK equation that accounts for nonlinearity, thermoviscous absorption, relaxation, and diffraction in directive sound beams. Calculations are presented which demonstrate the effect of relaxation on the propagation of a pulsed, diffracting, finite-amplitude sound beam.
Functional data analyses of lip motion
Authors: Ramsay J. O. , Munhall K. G. , Gracco V. L. , Ostry D. J.
Published: October 2005

The vocal tract’s motion during speech is a complex patterning of the movement of many different articulators according to many different time functions. Understanding this myriad of gestures is important to a number of different disciplines including automatic speech recognition, speech and language pathologies, speech motor control, and experimental phonetics. Central issues are the accurate description of the shape of the vocal tract and determining how each articulator contributes to this shape. A problem facing all of these research areas is how to cope with the multivariate data from speech production experiments. In this paper techniques are described that provide useful tools for describing multivariate functional data such as the measurement of speech movements. The choice of data analysis procedures has been motivated by the need to partition the articulator movement in various ways: end effects separated from shape effects, partitioning of syllable effects, and the splitting of variation within an articulator site from variation from between sites. The techniques of functional data analysis seem admirably suited to the analyses of phenomena such as these. Familiar multivariate procedures such as analysis of variance and principal components analysis have their functional counterparts, and these reveal in a way more suited to the data the important sources of variation in lip motion. Finally, it is found that the analyses of acceleration were especially helpful in suggesting possible control mechanisms. The focus is on using these speech production data to understand the basic principles of coordination. However, it is believed that the tools will have a more general use.
Energy flux density in a thermoacoustic couple
Authors: Cao N. , Olson J. R. , Swift G. W. , Chen S.
Published: October 2005

The hydro- and thermodynamical processes near and within a thermoacoustic couple are simulated and analyzed by numerical solution of the compressible Navier–Stokes, continuity, and energy equations for an ideal gas, concentrating on the time-averaged energy flux density in the gas. The numerical results show details of the heat sink at one end of the plates in the thermoacoustic couple.
Inverse scattering for the penetrable ellipsoid and ellipsoidal boss
Authors: Dassios George , Lucas R. J.
Published: October 2005

The inverse scattering problem for low-frequency plane-wave excitation of either a penetrable ellipsoid specified by its relative mass density and relative compressibility, or the corresponding ellipsoidal boss on a rigid base plane, is considered. For either situation, scatterer shape and orientation, as well as one of the constitutive parameters, may be obtained from a finite number of measurements of the leading order term in the low-frequency expansion of the scattering amplitude. Rayleigh’s result for this O(k3) contribution provides the analytical expression needed for the data inversion.
Computer simulation of auditory stream segregation in alternating-tone sequences
Authors: Beauvois Michael W. , Meddis Ray
Published: October 2005

A computer model is described that takes a novel approach to the problem of accounting for perceptual coherence in alternating pure-tone sequences by using simple physiological principles that operate at a low level. Using the same set of parameter values, the model is able to reproduce a number of phenomena associated with auditory stream segregation. These are (1) the buildup of stream segregation over time, (2) the temporal coherence and fission boundaries obtained from human listeners, and (3) the trill threshold. Whereas these phenomena are generally accounted for in terms of an auditory scene-analysis process that works on the basis of Gestalt perceptual principles, the operation of the model suggests that some Gestalt auditory grouping may be the product of low-level processes.
Contribution of Trafficking Signals in the Cytoplasmic Tail of the Infectious Bronchitis Virus Spike Protein to Virus Infection
Authors: Youn Soonjeon , Collisson Ellen W. , Machamer Carolyn E.
Published: October 2005

Coronavirus spike (S) proteins are responsible for binding and fusion with target cells and thus play an essential role in virus infection. Recently, we identified a dilysine endoplasmic reticulum (ER) retrieval signal and a tyrosine-based endocytosis signal in the cytoplasmic tail of the S protein of infectious bronchitis virus (IBV). Here, an infectious cDNA clone of IBV was used to address the importance of the S protein trafficking signals to virus infection. We constructed infectious cDNA clones lacking the ER retrieval signal, the endocytosis signal, or both. The virus lacking the ER retrieval signal was viable. However, this virus had a growth defect at late times postinfection and produced larger plaques than IBV. Further analysis confirmed that the mutant S protein trafficked though the secretory pathway faster than wild-type S protein. A more dramatic phenotype was obtained when the endocytosis signal was mutated. Recombinant viruses lacking the endocytosis signal (in combination with a mutated dilysine signal or alone) could not be recovered, even though transient syncytia were formed in transfected cells. Our results suggest that the endocytosis signal of IBV S is essential for productive virus infection.