bluuebunny/crossref_metadata_2025 huggingface dataset:
Actin in cochlear outer hair cells: A structural basis for cell shape and motility
Authors: Slepecky Norma
Published: October 2005

Threshold sensitivity and frequency selectivity in the cochlea depend on intact outer hair cells and models to explain these phenomena suggest that active mechanical processes, residing in outer hair cells, alter micromechanical properties of the basilar membrane. Auditory sensory hair cells isolated from the inner ear change their shape in response to stimulation in vitro. Three areas of the cell have been suggested to be involved in this form of cell motility: (1) the infracuticular network of actin filaments that is seen as a central core; (2) the cortical layer of actin filaments along the lateral wall; and (3) actin in the outer hair cell cytoplasm. The actin filaments in the stereocilia, the cuticular plate, and the infracuticular network are not involved, since mechanically disrupted cells lacking these structures still shorten. Actin filaments along the lateral wall are not involved in shortening since outer hair cell membrane ghosts do not shorten, however, they retain the ability to constrict so the cell becomes thinner. Shortening of outer hair cells does occur in mechanically disrupted cells as long as they contain some cytoplasm. Thus shortening of outer hair cells requires cytoplasmic components. Immunocytochemical studies have demonstrated the presence of microtubules, spectrin, calcium binding proteins, and actin in the outer hair cell. Staining with phalloidin indicates for the first time that actin is present as short filaments, and, with transmission electron microscopy, filaments are seen as a network throughout the cytoplasm. Thus actin may provide the structural basis for maintaining cell shape and for causing motility.
Effects of static indentation on the input-output function of Pacinian corpuscles
Authors: Bolanowski S. J. , Checkosky C. M.
Published: October 2005

The receptor potential (RP) of cat Pacinian corpuscles (PC) in response to sinusoidal displacements exhibit asymmetric, full-wave rectification. Furthermore, there are apparently two populations of PC, one more sensitive to stimulus compression, the other to withdrawal. These results can be explained by proposing that there are two groups of neutral elements within PC, each producing a half-wave rectified response but summing in polarity opposition. The RP may thus be dependent upon the relative contribution from the two groups. If true, then changes in the RP may occur with selective (de) activation of one group of elements. This may be tested by varying the static indentation of the vibrating probe, noting that small static indentations may permit only the most sensitive group of elements to be excited, revealing a half-wave rectified RP. Increasing indentations should then produce concommitant changes in the RP shape as the other group becomes activated. The experiments show that changes in static indentation produces changes in the RP, the changes considerably more complicated than the hypothesis predicts. The results indicate that while the two-group hypothesis may still be correct, the I-O function of each element may not resemble a half-wave rectifier. [Work supported by NS 23933.]
Significance of amino acid sequence in characterization of unidentified major proteins of the organ of Corti (OC)
Authors: Thalmann Isolde , Thalmann Ruediger
Published: October 2005

Previously, two low molecular weight, highly acidic proteins were discribed that are present at very high concentrations in the OC and that are assigned the tentative names OCP-1 and OCP-2 [Thalmann et al., Arch. Otorhinolarygol. 226, 123–128 (1980)]. Now amino acid sequencing studies of these proteins have been initiated. Preliminary results show that the N-terminal sequence of OCP-2 is Pro-Gly-Ile-Lys-Leu-Gln-Ser-Ser-Asp-Gly-Glu-Ile-Phe-Glu-Val-Asp-X-X-Ile-Ala-Lys-Gln-. Among the advantages of knowing the sequence or primary structure are (1) the primary structure contains all the information required for formation of the secondary and tertiary structure; (2) comparison with sequences of known proteins allows determination of the degree of homology, to obtain clues about evolutionary history and degree of conservation, and hints about protein function (e.g., the “EF hand” in some calcium-binding proteins); (3) repeating motifs suggest structural role; (4) internal homology suggests duplication (e.g., in calmodulin); (5) the nature of the N-terminal residue gives clues about the turnover of the protein; and (6) the amino acid sequence allows oligopeptides to be synthesized for obtaining antibodies for immunohistochemical studies and corresponding oligonucleotides to be synthesized for molecular biologic studies. [Work supported by NIH and DRF.]
Simulating pitch perception and sensitivity to phase using a peripheral auditory model
Authors: Meddis Ray , Hewitt Michael J.
Published: October 2005

The ability of neurophysiological studies to give an adequate account of human pitch perception was studied using a peripheral auditory model comprising (a) outer-ear, low-frequency attenuation, (b) a set of 60 digital filters to simulate basilar membrane frequency selectivity, (c) an array of inner hair cell simulators, and (d) a system based on Licklider's [Experientia 7, 128–133 (1951)] theory of pitch perception that generates running histograms of the time intervals among all spikes in fibers originating from adjacent sites on the membrane. The most frequently occurring time intervals were taken to represent the period of the perceived pitch, while the overall pattern of time intervals represented the perceived timbre. The model was tested, giving satisfactory results, using a wide range of harmonic, inharmonic, and noise stimuli known to give rise to pitch perceptions as well as stimuli, where the relative phase of the harmonic components affects stimulus timbre. [Work supported by SERC.]
Scattered ambient noise as an auditory stimulus for fish
Authors: Rogers Peter H. , Lewis Thomas N. , Willis Martha J. , Abrahamson Scott
Published: October 2005

In an earlier paper [P. H. Rogers, J. Acoust. Soc. Am. Suppl. 1 79, S22 (1986)], it was hypothesized that one role of the fish's auditory system may be to detect and localize nearby fish by “imaging” ambient noise scattered by their swim bladders. This is analogous to the role of the visual system of most animals, where the relevant signal is ambient light scattered by objects rather than light emitted by luminous objects. A classical conditioning experiment has been performed which indicates that the fish auditory system is capable of functioning in this manner. The ambient noise is provided by a J-9 transducer driven by Gaussian noise. Scattering of this noise by the resonant swim bladder is simulated by applying a filtered version of the noise signal to a small spherical projector. The “target strength” is bandwidth of the filter. The fish is conditioned to respond to the presence of the signal from the spherical projector. The fish's ability to detect this signal (as a function of range, bearing, etc.) is taken to be a measure of its ability to detect scattered ambient noise.
Reaction time measures of phantom image recognition in stereophonic listening
Authors: Brazzil H. , Yonovitz A.
Published: October 2005

Intensity stereophony allows the listener to perceive phantom images, which may be localized at any point on the imaginary soundstage existing between loudspeaker pairs. Specification of the phantom image typically relies on subjective evaluation by the listener. This study utilized reaction time to quantify the ability of listeners to accurately identify the image position as a function of frequency. Subjects were seated at 30-deg incidence to each loudspeaker in an anechoic environment. Each trial consisted of a pair of third-octave noise bursts at one of six frequencies (250–8000 Hz). The first of each stimulus pair was presented with no interloudspeaker intensity difference (phantom center). The second stimulus occurred randomly at phantom center, phantom left, or phantom right, and subjects were instructed to correctly respond as quickly as possible in this three-choice forced response task. Interloudspeaker intensity difference for images occurring left or right of center was 2, 4, or 6 dB. Longer reaction times occurred for center image responses, independent of frequency. Shortest reaction times were obtained at 2 kHz, with increasing latencies occurring at higher frequencies. Data suggests that phantom image identification in stereophonic listening is compromised above 2 kHz.
Comparisons of between- and within-subject variability in repeated-measured auditory brain-stem responses (ABRs) in 5–6-year-old children
Authors: Lord-Maes Janiece M. , Lauter Judith L.
Published: October 2005

In reports to this Society, and publications [J. L. Lauter and R. L. Loomis, Scand. Audiol. 15, 167–172 (1986); Scand. Audiol. 17, 87–92 (1988)], results of repeated-measures ABR testing in young adults have been described, indicating the variability of peak parameters, such as latency and amplitude, provides information that absolute values of these parameters do not: contrasts in between- versus within-subject consistency, and by ear of stimulation. Seven 5–6-year-old children were tested in eight weekly sessions for ABRs to right, left, and binaural clicks, and see adultlike patterns based on nonadult values: (1) contrast in between-versus within-subject consistency; (2) peak differences; and (3) ear differences. Preliminary comparison between these data, a study on 10-year-old males, and 15 young adults suggest that ABR variability may be sensitive to auditory-system developmental changes that continue long after ABR absolute peak latencies have achieved “adult” values. [Work supported in part by AFOSR.]
Comparison of rate effects on the auditory middle latency evoked response (MLR) in young and elderly adults
Authors: Ryan Jody Newman , Moushegian George
Published: October 2005

Middle latency responses (MLR) are rate sensitive in infants but less rate sensitive in adults. It has been suggested that developmental factors at both ends of the age continuum may influence MLR [Jerger et al., Sem. Hear. 9, 75–86 (1988)]. Effects of rate in the elderly are unknown. This study was undertaken to determine how rate alters the waveforms of the MLR in elderly subjects. Tone bursts of 500 and 2000 Hz were presented at two sensation levels (30 and 60 dB SL) monaurally and binaurally at six repetition rates: 3.1, 9.1, 15.1, 27.1, 39.1 (the 40-Hz, or steady-state, response), and 51.1/s. The responses of young (under 35 years) and older (over 60 years) subjects were compared. The results revealed that the waveforms are similar for the two groups at different rates, with the exception of latency prolongations, especially for the later waves (e.g., Pb at 50–60 ms), in the older subjects. Furthermore, at the higher rates, the amplitudes of the waveforms of the older subjects are larger than those in the younger group.
Suppression of shock-associated noise from improperly expanded jet flows
Authors: Dosanjh Darshan S.
Published: October 2005

Experimental aeroacoustic investigations of the reduction of intense noise radiated by improperly expanded turbulent jet flows are reported. The noise intensity varies with the strength of the repetitive shock structure inherently present in improperly expanded jet flows. To reduce shock-associated noise levels, the needed weakening of the repetitive shock structure is achieved when improperly expanded jet flows issue (1) from a plug nozzle with either a contoured plug or a conical perforated plug operated at a range of above-critical pressure ratios; (2) from coaxial nozzles of different configurations operated in the inverted pressure mode. Farfield acoustic results and the supporting optical records of these improperly expanded jet flows are presented. Striking changes in sound pressure level spectra, overall sound pressure level directivity, and substantial reductions in the intensity of shock-associated noise are reported. Suppression of shock-associated noise from improperly expanded turbulent jet flows issuing from a plug nozzle operated at off-design pressure ratios is shown to be more effective than that for jet flows from an equivalent contoured convergent-divergent nozzle operated in the over- and underexpanded modes.
Group delay and reverberation in multi degree of freedom systems
Authors: Boulahbal Djamil , Lyon Richard H.
Published: October 2005

Signals that travel in multi degree of freedom (dof) systems experience group delay that is a function of system geometry, modal density, damping, and signal processing procedures. This paper is interested in developing inverse filters for such systems for the purposes of mechanism and structural diagnostics, and the dereverberation of response signals. The design of inverse filters is greatly aided if the process can begin with approximations to the system transfer functions that are based (at least in part) on conceptual models for the system dynamics. In this paper, the theoretical basis for such models is outlined, including the effects of signal processing procedures. The various elements of these models that have been tested experimentally, and the results of these studies will be presented.
A comparison between the boundary element method and the superposition method for the analysis of the scattered acoustic fields from rigid bodies and elastic shells
Authors: Miller Russel D. , Huang Hansen , Moyer E. Thomas , Überall Herbert
Published: October 2005

The steady-state analysis of submerged rigid and elastic bodies using two approaches is presented. In the first approach, a combined finite element/boundary element approach is used. The finite element program NASTRAN (NASA structural analysis) is used to formulate the structural matrices. The SIERRAS (surface integral equation radiated noise and analysis) program is then used to solve the coupled fluid-structure interaction problem. A superparametric boundary element with nine nodes is used. In the second approach, the superposition method is employed for modeling the fluid. The superposition method employs a number of point sources moved inside the body to represent the fluid response at the surface. This allows the fluid matrices to be formed without surface integration. Formulations for the superposition method are given for both the radiation and scattering problems. The methodologies are demonstrated for the scattering of an infinite set of plane waves from a submerged rigid sphere, prolate spheroid, and elastic spherical shell.
Diagnostic tests of segmental duration models
Authors: van Santen Jan P. H. , Olive Joseph P.
Published: October 2005

Duration models map combinations of segmental identities and multi-factorial prosodic contexts onto the temporal domain. Two new diagnostic tests that focus on interactions between contextual factors were applied to vowel durations measured in contexts varying in several prosodic factors and speaking rate. The first test concerns a distinction that cuts across a wide array of models (e.g., additive, multiplicative): Which groups of factors are functionally combined? When factors are functionally combined, constellations of values that yield identical durations for one segment should also yield identical durations for other segments. The data-showed that speaking rate cannot be combined with other prosodic factors, contradicting any generalized version of the incompressibility model [D. H. Klatt, J. Acoust. Soc. Am. 59, 1208–1221 (1976)] that would count speaking rate among its prosodic factors. The second test concerns modes that would count speaking rate among its prosodic factors. The second test concerns models that express duration as the sum of additive and multiplicative terms, and can diagnose which terms are needed. Results included that speaking rate is combined with segmental identity into a single multiplicative term. These results show the advantages of diagnostic tests over the standard approach of model fitting.
Voice conversion and its applications
Authors: Jianping Pan
Published: October 2005

This approach depends on assumptions and previously proposed conclusions [D. G. Childers et al., Proc. ICASSP 85, 748–751]. Some corresponding voiced phonemes are extracted from the source speech and target speech to compare spectrum differences for vocal tracts of these two kinds of speech. Vocal tract lengths mainly determine spectrum distributions; they do not change greatly and are assumed to have the same varying tendencies from segment to segment while terminal radiation, etc. slightly influence spectrum distribution. These imply that there is a non-time-varying nonlinear frequency-shifting function obtained by comparing corresponding spectrum parts (especially formants) of corresponding phonemes for source and target voices. Changes of vocal tract areas based on physiological acoustics and terminal radiations for two voices are assumed to have the same tendencies for influencing the corresponding spectra from phoneme to phoneme. A non-time-varying filtering function therefore needs to be fixed by amplitude comparison between corresponding-phoneme spectra for the frequency-shifted source and target voices. Since the glottal pulse shapes remain nearly the same, and any two kinds of pitch change with the same tendencies from segment to segment, the pitch conversion factor is determined from comparing the corresponding phonemes for two voices and an excitation model whose shape is closest to that of the target voice. During voice conversion, the spectrum of the source speech is processed with the above two functions and the excitation model is impulsed by the pitch-converted target pitch from segment to segment. Areas of applications are: (a) restoring helium speech; (b) mimicking voice; and (c) preprocessing speech for recognition.
Statistical tree-based modeling of phonetic segment durations
Authors: Riley Michael D.
Published: October 2005

Segmental durations are affected by many factors: phonetic context, speaking rate, stress, word and phrasal position, etc. Regression trees [L. Breiman et al., Classification and Regression Trees (Wadsworth, Monterey, CA, 1984)] are well suited to capturing these effects, since they (1) statistically select the most significant features, (2) permit both categorical and continuous factors to be considered, (3) provide “honest” estimates of their performance, and (4) allow human interpretation and exploration of their result. In particular, transcribed databases of 400 utterances from a single speaker and 4000 utterances from 400 speakers of American English were used to build optimal decision trees that predict segment durations based on such factors. Over 70% of the durational variance for the single speaker and over 60% for the multiple speakers were accounted for by this method when using information only at the word level and below. These terms were used to derive durations for a text-to-speech synthesizer and were found to give more faithful results than the existing heuristically derived duration rules. Since tree building and evaluation is rapid once the data are collected and the candidate features specified, the technique can be readily applied to other feature sets and to other languages.
A thermoacoustically driven orifice-pulse-tube cryocooler
Authors: Swift G. W. , Martin R. A. , Radebaugh Ray
Published: October 2005

The orifice pulse tube is a variant of Stirling-cycle refrigerator in which the cold, work-absorbing piston and crankshaft are replaced by a simple dissipative structure. To date, the oscillatory pressure needed to drive pulse tubes has been provided by complex, unreliable room-temperature pistons and crankshafts. In this presentation, plans and design calculations for driving an orifice pulse tube with a thermoacoustic engine will be discussed. In this composite device, heat flowing from a high-temperature source to a room-temperature sink will generate high-amplitude acoustic oscillations in high-pressure helium gas; these oscillations will power the orifice pulse tube, thereby pumping heat from a low-temperature source to a room-temperature sink. Thus the device is a heat-driven cryocooler with no moving parts. in this planned small laboratory device, it is expected that a few W of refrigeration at roughly 80 K using about 2 kW of heat at 1000 K will be produced. The nature of the oscillatory heat transfer and time-averaged enthalpy flow in the various components of the engine and cooler will also be discussed, comparing and contrasting the acoustic-frequency Stirling cycle in the cooler with the thermoacoustic cycle in the engine.
Vortices as a natural aeroacoustic engine
Authors: Kurosaka M.
Published: October 2005

In previous investigations, it was found that the so-called Ranque-Hilsch effect is induced by a spinning acoustic wave present in swirling flows; the total temperature within the vortices becomes acoustically separated. Another similar example for the Karman vortex street or an array of vortices formed a bluff body is presented here. The vortices in the wake are found to have the capacity to separate the total temperature, and the separation is significantly enhanced by acoustic resonance. Here, vortices behave as a natural “compressor-turbine” cycle, its performance improved substantially by acoustics.
Source level limits for submerged thermoacoustic sound sources
Authors: Gabrielson Thomas B.
Published: October 2005

One application for thermoacoustic engines is the generation of sound underwater. In theory, the engine resonator could either be flooded with water and radiate directly into the surrounding water, or the resonator could be gas-filled. The radiation performance of a liquid-filled resonator (taken to be an open-ended tube) radiating into the same liquid is well known; however, the open end of a submerged, gas-filled tube is almost a velocity node, so a smaller fraction of the stored energy “leaks” out as radiation. For the same pressure amplitude in both the liquid-filled and gas-filled tubes, the particle speed is much higher in the gas-filled tube, and this more than compensates for the smaller transmission coefficient into the surrounding liquid. In either case, limits to the acoustic power output can be calculated from the resonator radiation efficiency and from the peculiar requirements of the thermoacoustic engine.
Coherence theory in volume scattering and structural acoustics
Authors: Beran Mark J. , McCoy John J.
Published: October 2005

In this paper, the use of the two-point coherence function, defined for arbitrarily positioned points, to study wide-angle volume scattering problems in the ocean and wave propagation in cylindrical shells subject to random forcing is considered. Although the basic equations of the two phenomena are different, it will be shown that the basic approach developed 30 years ago in optics is a useful way to study these and similar problems. First, the theory of partial coherence developed in optics for free-space propagation from random sources is reviewed. Then, the coherence equations for the cylindrical shell propagation case are formulated, and it is shown how the equations may be solved when the two-point statistics of the forcing function are known.
Nonlinear wavetrains in dense gases with large specific heats
Authors: Cramer M. S. , Pelz W. , Watson L. T.
Published: October 2005

Periodic wavetrains propagating in fluids whose specific heats are large compared to the molal gas constant are examined. In the dense gas regime, the fundamental nonlinearity parameter 1 + B/2A of these fluids may become negative. The present study examines the nonclassical properties of the evolution of a sinusoidal wavetrain including the formation and propagation of expansion shocks and sonic shocks. Analytical solutions are presented for the inviscid problem and are compared to numerical solutions describing the dissipative evolution.
Formant contour estimation in noise using a spectral estimation “confidence measure.”
Authors: Sreenivas T. V. , Niederjohn R. J.
Published: October 2005

Estimation of formant contours from continuous speech is a difficult problem that has required either elaborate heuristic rules or complex hidden Markov models. Under high noise levels, these methods deteriorate significantly because of the degraded performance of the spectral estimator on which they are based. This paper proposes a method of formant contour estimation using a measure of confidence for the spectral peak estimation. At high noise levels, most spectral estimation techniques result in large variance and increased spurious/missing peaks; however, it is found that a broad distribution of spectral energy can be determined more reliably using filter-bank analysis. This spectral energy distribution is utilized to differentiate regions of high and low signal-to-noise ratio in the spectrum (for white noise corruption), which in turn is used to determine a “confidence measure” for the spectral peak estimation. The addition of this confidence information to the noisy spectral peak data of a speech utterance results in clear segments of the formant contour standing out from the remaining noisy peak data. Using these segments as anchor regions, an algorithm is developed to determine the complete contours, within the constraints of the known speech properties. [Work supported by NSF.]
Identification of onset order for two-tone components: Implications for voicing perception
Authors: Layer Jody K. , Pastore Richard E.
Published: October 2005

A general account of voicing perception for initial position stop consonants varying in VOT has been offered based on the identification of onset order of component events. Pisoni [J. Acoust. Soc. Am. 61, 1352–1361 (1977)] reported categorical perception for nonspeech tonal stimuli, although the exact boundary locations differed from VOT speech boundaries. The current research replicates and extends the Pisoni study. Labeling task boundaries were in agreement with Pisoni, and a two-interval, forced-choice (2IFC) task yielded boundaries even shorter than those for the labeling task. Most synthetic speech stimuli varying in VOT employ an initial burst at onset. Adding a noise burst to the beginning of the tone stimulus shifted the temporal-order labeling boundaries to significantly longer onset asynchronies that are consistent with those reported for VOT. Implications for temporal-order processing and speech perception will be discussed. [Work supported by NSF.]
Articulatory and acoustic signatures of selected monosyllabic words
Authors: Kent Ray D. , Weismer Gary
Published: October 2005

At previous meetings of this Society, acoustic signatures for selected words from an intelligibility test have been described. The signatures consist minimally of the formant trajectories of the syllable nucleus of each word. The formant frequency information can be augmented by other acoustic information, such as information on nasal murmurs, stop bursts, silences, and frication intervals. A major goal of this work has been to determine the interspeaker variance of the signatures and to evaluate their usefulness in characterizing speech disorders. This report extends the research to include articulatory data obtained by x-ray microbeam. The articulatory signatures take the form of planar motion paths of radiopaque markers attached to the articulators. Articulatory data were obtained from five talkers. Selected results will be presented to illustrate the articulatory signatures and to show their relationships to acoustic signatures of the same words. The primary goal of this report is to describe intraspeaker and interspeaker variances as they relate to the possibility of developing nonnative standards for articulatory-acoustic signatures. [Work supported in part by NIH.]
Assessing the perception of foreign speech sounds
Authors: Rochet Bernard
Published: October 2005

This paper reports the results of a series of tests in which a set of synthetic /sVt/ stimuli was presented to native speakers of Standard French and Western Canadian English in order to assess the effect of phonemic interference as a perceptual phenomenon. Each linguistic group was asked to categorize the vowel portion of each stimulus in terms of its L1 phonological system, and, in a second test, in terms of its L2 system. In addition, subjects were asked to rate each stimulus as to the adequacy of its vowel as a member of its class. The results provide a representation of the subjects' perceptual categorizations of a subset of the vowel space of their native and their target languages (English /u/ and /U/, and French /u/ and /ü/). Analysis reveals that English /u/ is characterized by significantly higher F2 values than its French counterpart, and that few subjects at the beginner or the intermediate level perceive L2 phonemes in the same way as L2 native speakers; for most, the acoustic specifications of L2 vowels match closely those of their L1 vowels, or are intermediate between the L1 and L2 values, in keeping with the notion of phonetic learning.
Categorization of nonspeech stimuli
Authors: Li Xiao-Feng , Layer Jody K. , Pastore Richard E.
Published: October 2005

A number of studies have claimed that a continuum consisting solely of auditory chirps or bleats produces uniform chance labeling and discrimination performance. However, when these auditory continua are added to an appropriate syllable base, they produce a categorically perceived place continuum. The current study demonstrates that practice allows subjects to categorically perceive these auditory continua in a manner equivalent to that reported for speech place continua. Three sets of 16 sinusoidal stimuli were synthesized with 40-ms initial transitions that were analogous to the second formants of syllables. The starting frequency of the transitions varied in 15 equal steps from 1140 to 2420 Hz. The duration of the final steady-state portion of the stimuli was 190, 40, or 0 ms [bleats, short bleats, and chirps] with total duration of 230, 80, or 40 ms, respectively. The study consisted of 4 practice days with initial testing on each day, and followed by 2 days of reevaluation of labeling performance. [Work supported by NSF.]
Accuracy and reliability of formant frequency measurements in synthetic infant CV syllables
Authors: Roussel Nancye C. , Daniloff Raymond G. , Miller Creighton J.
Published: October 2005

An investigation of the reliability and accuracy of measurement of infant formant frequencies was conducted. Four factors known to render formant measurement difficult—pitch inflection, glottal noise, jitter, and nasalization—were incorporated into synthesized CV (C = /b,d/, V = /i,a,ɛ/) syllables appropriate to 3-month-olds. The syllables were of high intelligibility and quality. Three fundamental frequency contours (standard rise/fall, rising, flat), three F0 levels (325, 375, 425 Hz), four voice/noise ratios (+20, +5, 0, −15), three frequency jitter rates (250, 500, 750), and one degree of nasal coupling were used. Formant frequency measurements were made in two ways for each token: (1) as single FFT cross sections using a 10-ms window and (2) as averaged, time-advanced FFT spectra. In the second condition, three successive FFTs taken at 2.5-ms rightward shifts of the 10-ms sampling window were averaged to produce the FFT spectrum for measurement. Three observers independently measured F1, F2, and F3 and results were compared to synthesis parameter values. Inter- and intraobserver reliability was also computed. Results are discussed with regard to the influence of consonant place and vowel type upon accuracy in each of the four conditions of waveform perturbation.
Fundamental and formant frequencies in an adolescent population
Authors: Merino Susan R. , Nearey Terrance M.
Published: October 2005

Although measurements of children's, adult male's, and female's vowels are readily available in the literature, few studies can be found that deal with the resonances of the adolescent vocal tract. The adolescent population is of interest because of the variation in vocal tract lengths that it provides and the consequent effects of this variation on the formant frequencies of the vowels. Recordings were made of 11 vowels produced by 30 junior high school students, 16 male and 14 female, between 11 and 16 years of age. The students were attending the same school and were all native speakers of the same dialect. Measurements of the fundamental and formant frequencies were taken from two tokens of each 11 vowels for all of the speakers. A preliminary analysis of the data will be presented.
APS: An environment for acoustic phonetic research
Authors: Watson Gordon S.
Published: October 2005

Continuous speech recognition systems based on acoustic phonetic features demand characterization of the relationship between phonetic segments and their acoustic values. This paper describes a software environment for exploring this relationship. The software system is known as APS—acoustic phonentic research with S (the standard UNIX statistical package). APS implements a language formalism for describing segments of speech, forming an interface between the domain of phonetics and a rich speech database. APS enables the automatic retrieval of all tokens of a given segment type together with their acoustic parameter values in a phonemic context specified by the user: For example, using APS, it is possible in a single instruction to perform statistical operations (e.g., mean, variance) on the durations of all word-final oral stops following stressed vowels [T. H. Crystal and A. S. House, J. Acoust. Soc. Am. 83, 1553–1573 (1988)]. The motivation for APS and the principles of its design are described and examples of its usage are given.
Effects of changes in stress and in rate of speech on vowels
Authors: Fourakis Marios
Published: October 2005

The effects of changes in stress and in rate of speech on the acoustic characteristics of American vowels as produced by native speakers in real words were examined. The words were embedded in a carrier sentence. Subjects were instructed to produce four repetitions of the carrier sentence for each test word under each of four conditions: (a) slow, (b) fast, (c) stress on the test word, and (d) stress on an attached dummy syllable. There were 32 tokens per vowel for each speaker. The utterances of one male speaker have been completely analyzed and plotted in an auditory-perceptual space [J. D. Miller, “Auditory-perceptual interpretation of the vowel,” J. Acoust. Soc. Am. (in press)]. The vowel target zones described by Miller correctly classify 85% of the vowel data, regardless of stress and rate conditions; and with minor modifications, the accuracy of classification is improved. Data for one female speaker will also be presented. Furthermore, measurements of sentence, word, and isolated vowel durations will be presented for both speakers. [Work supported by NINCDS.]
Digital processing of laryngeal images: A preliminary report
Authors: Colton Raymond H. , Casper Janina K. , Brewer David W. , Conture Edward G.
Published: October 2005

A low-cost microcomputer (Amiga 1000) and software were used to digitize and analyze slides, high-speed films, and videotapes of laryngeal images. The images were digitized with a 320 horizontal × 200 vertical pixel resolution and at 16 grey levels. Various algorithms were used to analyze the images, which included color equalization, color merging, edge detection, and histogram analysis. An example is presented where the area of a nodule and the area of the glottis are measured using some of the processing techniques and compared to similar measurements obtained by hand. The quality of the digitized images obtained with this low-cost system is very good. Simple image processing techniques, commercially available, are well suited to the analysis of laryngeal images and should permit more sophisticated processing of movement of structures within the larynx.
Mixed spectral representation—Formants and LPC coefficients
Authors: Olive Joseph P.
Published: October 2005

A cascade formant model is well suited to describe certain speech segments, such as vowels and vowel-like sounds. The formant model is also useful because the relationship between formants and the vocal tract configurations are well understood; however, this model is not adequate for other speech sounds, such as stops, fricatives, nasals, etc. On the other hand, LPC analysis, of sufficiently high order, can adequately describe the spectrum of any speech sound, but the relationship between the LPC parameters and the spectrum or vocal tract configuration is not obvious. This paper describes a speech analysis/synthesis scheme that uses both formants and LPC parameters for different sections of a speech signal. Thus, in some regions, the benefit of the formant model can be utilized, while, in other regions, the LPC representation can be used to obtain a good description of the speech spectrum. The analysis algorithm resolves the problem of discontinuities that arise from using the two different spectral representations. The method of speech analysis described in this paper produces resynthesized speech of the quality of multipulse LPC.
Finite amplitude effects on the propagation of a pulsed sound beam in a dissipative fluid
Authors: Frøysa Kjell-Eivind , Tjøtta Jacqueline Naze , Tjøtta Sigve
Published: October 2005

The linear and nonlinear propagation of a pulsed sound beam generated by a real source in a fluid is considered. The source can be plane or weakly focusing. The investigation is based on a linear and quasilinear solution of the Khokhlov-Zabolotskaya-Kuznetsov nonlinear parabolic equation. Analytical and numerical results are presented. The evolution of the pulse as it propagates from the source into the farfield region is investigated for various pulse forms. The special case of a source with distribution exp(−x2/a2)r(t) (x radial distance, t time) is investigated in detail, with emphasis on the role of diffraction and absorption on the self-demodulation of the pulse. The results are related to the problem of scattering of sound by sound. [Work supported by the IR&D program of ARL:UT and VISTA/STATOIL, Norway.]
Measurement of bubble properties using a multi-frequency sound field
Authors: Atchley Anthony A. , Perron Robert A. , Lineberger Ernest R.
Published: October 2005

A problem of continuous interest in underwater sound propagation is the prediction of the scattering properties of bubbles. Two important parameters in this problem are the bubble's radius and damping coefficient. A method of measuring these parameters, which is a modification of a bubble-sizing technique developed by V. L. Newhouse and P. M. Shankar [J. Acoust. Soc. Am. 75, 1473–1477 (1984)] is described. The method exploits the nonlinear, mixing property of resonant bubbles simultaneously exposed to sound fields of different frequencies. The results of measurements of bubble radius and resonance damping coefficient are presented for bubbles having resonance frequencies less than approximately 100 kHz. Extension of the technique to smaller bubbles is discussed. [Work conducted for the Naval Coastal Systems Center and funded by the Naval Postgraduate School.]
Possible observation of chaos in acoustics
Authors: Cook Bill D.
Published: October 2005

Approximately 20 years ago, I observed an acoustic phenomenon that could have been chaos. Not understanding what I was observing, I found that I could maintain experimental conditions to prevent it from occurring. I did so in order to complete the task at hand. The study involved understanding what conditions subharmonics were generated in an ultrasonic standing wave cavity. Two air-backed quartz transducers were placed in a Fabry-Perot configuration with water; one transducer having a resonant frequency of about 1 MHz; the other always being at lower frequency. Their separation was adjustable to be between 5 to 10 cm apart. The 1-MHz transducer was driven with a variable frequency oscillator. At sufficient power and at some driving frequencies, subharmonics were observed both optically and with a piezoelectric transducer. Upon the onset of subharmonics, an optical diffraction pattern displayed lines in between the lines normally observed. A frequency analyzer connected to the piezoelectric transducer showed subharmonics and the corresponding idlers. Under some higher power conditions, the optical pattern became a smear and the frequency analyzer display became uninterpretable. In retrospect, I now believe what I was observing was chaos.
Recent developments in piezoelectric composites for transducer applications
Authors: Ting Robert Y.
Published: October 2005

The design trend for future sonar transducers is to emphasize the utilization of hydrostatic-mode sensing, as opposed to the classical 31- or 33-mode configuration in a Tonpiltz transducer. The conventional PZT-type ceramics cannot meet this need because they have very low hydrostatic piezoelectric coefficients. Piezoelectric PVdF polymers are attractive for this type of applications because of their high sensitivity, but they are limited by their poor temperature stability, low dielectric constant, and planar anisotropy. Piezoelectric composites have therefore been considered as alternate transduction materials that can be used for hydrostatic-mode sensing. Recent developments in ceramic/polymer composites having 1–3 and 0–3 connectivity patterns and nonferroelectric glass/ceramic composites will be discussed. Some test results on the acoustical performance of prototype hydrophones will also be presented to demonstrate the potential of these new materials for underwater acoustical applications. [Work supported by ONR.]
Silicon transducer technology
Authors: Henrion W. S.
Published: October 2005

The use of integrated circuit technology to build mechanical structures by the use of silicon micromachining has gained wide acceptance for some sensor types over the past 10 years. The principal application for silicon micromachining has been for pressure transducers used in the automotive and medical markets. The use of silicon micromachining technology in acoustical sensors has been somewhat limited, although some microphones and accelerometers have been built using this technology. This paper will review the micromachining technologies with specific application to the acoustics and acceleration sensors. Examples will be given for microphones, accelerometers, and pressure transducers with the material process technology used for their manufacture. Projections are made of future trends in silicon micromachining technology for acoustic transducers. The electronic interface to these acoustic and acceleration transducers are explored.
Vibrotactile measurement procedure for assessing peripheral neuropathies
Authors: Brammer A. J. , Piercy J. E.
Published: October 2005

It has been suggested that some peripheral neuropathies may be detected earlier by vibrotaction than by more traditional methods (viz., nerve conduction). Most commercial apparatus for this purpose is designed primarily for use on any flesh surface, and only records the sensitivity of one mechanoreceptor type. Recent laboratory studies have identified a technique for establishing, independently, the sensitivity of each of the three receptor populations essential for the sense of touch at the fingertip, with minimal effect from confounding variables. A portable measurement system using this technique has now been developed for clinical use or field surveys, which enables the thresholds of untrained subjects to be determined rapidly, by employing audiometriclike procedures. The data are conveniently summarized by “tactograms,” or “tactilograms,” in which the change in vibrotactile threshold from the mean value recorded in normal hands, at each frequency, is expressed graphically, in a manner similar to an audiogram. Results from persons with diagnosed or suspected neuropathies have revealed three patterns of threshold shift, at least one of which is receptor specific.
Identifying possible neural codes for vibrotaction using the theory of temporal summation
Authors: Checkosky C. M. , Bolanowski S. J.
Published: October 2005

The theory of temporal summation refers to the psychophysical phenomenon in which threshold decreases with increasing stimulus duration. The effect is found in audition and is central. Vibrotactile thresholds mediated by the Pacinian-corpuscle (PC) population (the “P” channel) also exhibit temporal summation. Assuming that the tactile summator is also central, it may be possible to determine the neural code for threshold used by the P channel. Theoretically, temporal summation predicts a decrease in threshold at a rate of −3 dB/doubling of duration from 10 to 100 ms. Thus by integrating the response from single fibers for various response criteria, those not having the potential for temporal summation can be rejected as possible coding schemes. PCs isolated from cat mesentery were stimulated with bursts of vibrations (300 Hz) having durations from 10 to 1000 ms, the intensity of the stimuli adjusted for fixed criterion responses of 1, 2, and 4 impulses/burst and 1 impulse/cycle. Data were sampled over the entire burst duration, in effect analyzing the response with an ideal summator. The decreases in intensity for increases in duration from 10 to 100 ms were −0.9, −1.2, −2.3, and −0.2 dB/doubling, respectively, with neither the 1 impulse/burst nor the impulse/cycle criteria showing significant summation. The other two criteria show modest summation, indicating that they have the potential for being the neural code for threshold in the P channel. [Work supported by NS23933.]
Vibration characteristics of rectangular test soundboards
Authors: Suzuki Hideo
Published: October 2005

Since a piano soundboard has a very complex structure, it is difficult to separately study the effect of each parameter (such as the board thickness, rib dimensions, bridge dimensions) on the vibration characteristics of the whole soundboard. To more effectively study the effect of these parameters, four test soundboards were built. A much simpler structure was used to study the vibration characteristics of a spruce panel reinforced with several spruce ribs. Driving point inertance functions at different points were compared among the four soundboards. Mode numbers and modal patterns were also compared. It is interesting that the vibration at a point on (or near) a rib is quite different from that on a point away from ribs in the frequency range above the coincidence frequency. [This study was performed while the author was at CBS Technology Center, Stamford, CT and supported partially by Steinway and Sons, Long Island City, NY.]
Nonlinear modeling of piano hammer-string interaction
Authors: Hall Donald E.
Published: October 2005

Measurements of compliance on real piano hammers show that they are not well represented by Hooke's law, and it has been found that theoretical models with linear compliance have only modest success in accounting for measured string vibration spectra. Two new computer programs now perform numerical integrations of the interaction process for hammers with nonlinear compliance. One treats the string as a pair of digital delay lines, and is limited to perfectly flexible strings. The other represents the string by its normal modes, and can include string stiffness. Results from these two programs agree well with each other, and provide improved agreement with laboratory measurements.