bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of learning English as a second language on the acquisition of a new phonemic contrast
Authors: Streeter L. A. , Landauer T. K.
Published: October 2005

Very sharp discrimination functions for the timing of voice onset relative to stop release characterize perceptual boundaries between certain pairs of stop consonants for adult speakers of many languages. To explore how these discriminations depend on experience, we studied their development among Kikuyu children, whose native language contains no stops in which voicing is subtantially delayed relative to stop release (e.g., /p/). Kikuyu distinguishes stops in which voice onset substantially precedes release (prevoiced) from those in which voice onset is nearly simultaneous with release (voiced) for apical and velar places of articulation. However, the language has only a single prevoiced labial stop. Prior to exposure to English, children discriminated prevoiced from voiced labials and voiced from voiceless labials, although these distinctions are not phonemic in Kikuyu. Moreover, the voiced/voiceless discrimination for labials ([ba] versus [pa]) improved markedly with schooling in English, rapidly surpassing the prevoiced/voiced distinction. Apparently, certain voice onset time differences are naturally discriminable, but it is also apparent that the very fine voiced/voiceless discrimination among adults for whom it is phonemic is largely attributable to experience.
Automatic generation of voiceless excitation in a vocal-cord/vocal-tract speech synthesizer
Authors: Flanagan J. L. , Ishizaka K.
Published: October 2005

A vocal-cord and vocal-tract model, described earlier [Proc. 8th Int. Congr. Acoust., London (1974)], synthesizes speech from physiologically based control parameters. The parameters represent subglottal (lung) pressure, vocal-cord tension, vocal-cord rest area, and vocal-tract shape. Voiced sounds are generated from these controls by a dynamic model of the vocal cords. Voiceless sounds are generated from exactly the same input parameters by automatic computation of turbulent flow at constricted places in the vocal tract. The complete model is programmed on a laboratory computer and the automatic computation of voiceless excitation is demonstrated.
Context-conditioned adaptation of liquids and their third formant components
Authors: Verbrugge R. R. , Liberman A. M.
Published: October 2005

The third formant transition is an important acoustic dimension in the identification of /r/ and /l/ by English listeners [Miyawaki et al. (in preparation)]. In this study, six listeners showed a consistent decrease in “r” responses following repeated presentation of /r/ stimuli and a complementary increase following /l/ stimuli. These shifts are similar to those found for perceptual boundaries between stops. Further tests suggest the shifts are not due to adaptation of context-independent formant-transition detectors: (1) repeated presentation of the isolated third formants from the original adapting stimuli produced no consistent boundary shifts; (2) when the listeners were asked to categorize the full series of isolated third formants, the nonspeech boundaries often differed from the speech boundaries; (3) the nonspeech boundaries were unstable, and no consistent shifts could be induced by either speech or nonspeech adapting stimuli. Adaptation effects may be restricted to adapting and test stimuli which are members of the same natural class of events.
Frequency analysis by neuronal populations in the inferior colliculus of the rat
Authors: Harris D. M. , Rosenfeld J. P.
Published: October 2005

Response pattern changes of 52 single inferior colliculus (IC) neurons measured as a function of frequency and intensity changes of pure-tone-burst stimuli were analyzer in the form of peri-stimulus-time histograms (PSTH). Through pooling of single unit data and by direct measurement (multiunit PSTH), the typical response pattern of IC neuronal populations was described. This response was an initial damped oscillation (excitation-inhibition) following stimulus onset which was followed by the establishment of a new baseline level of cellular activity that terminated at stimulus offset. A multiunit analysis of the tonotopic organization of rat IC revealed a pattern of activity within populations as predicted by Békésy [Sensory Inhibition (Princeton U.P., Princeton, N.J., 1967)] and I.C. Whitfield [The Auditory Pathway (Camelot Press, London, 1967)]. The onset response was widespread, but sustained excitation was restricted to specific loci for specific tonal frequencies. These excitatory loci were bordered by populations which exhibited sustained inhibition and were observed to shift along a dorso-ventral axis with changes in stimulus frequency.
Response properties and distribution of delay-sensitive neurons within the central nucleus of the inferior colliculus of the cat
Authors: Roth G. L. , Merzenich M. M.
Published: October 2005

Responses of single neurons within the central nucleus of the inferior colliculus to dichotic tonal and noise stimuli have been investigated. The responses of many neurons sensitive to interaural time difference (Δt) across the range that a cat utilizes in sound localization have been studied; neuronal responses were related to their location within the nucleus. Results include the following: (1) The response of most but not all neurons in the low-frequency representational region of the central nucleus was a dramatic function of Δt across the behavioral range; (2) the optimal Δt across the behavioral range determined for any given unit was similar for stimulation at different frequencies and intensities, and with wide-band noise. For many neurons, maximal response was seen at a Δt outside the behavioral range. (3) the Δt's at which different neurons responded maximally encompassed the entire behavioral range; most responded maximally with the contralateral side leading. (4) Units encountered within a penetration vertical to isofrequency contours responded maximally at similar Δt's, although exceptions were seen. Neurons sensitive to Δt's across the behavioral range appear to be spatially ordered within the central nucleus. [Supported by NIH Grant NS-10414.]
Projections of the anteroventral cochlear nucleus in the three shrew (Tupaia glis)
Authors: Zook J. M. , Jones D. H. , Casseday J. H.
Published: October 2005

The anteroventral cochlear nucleus (AVCN) of the tree shrew can be divided into anterior and posterior parts on the basis of cytoarchitecture. Projections from these two areas were studied by making electrolytic lesions and tracing the anterograde degeneration that resulted with the Fink-Heimer method. Following large AVCN lesions, degeneration was found ipsilaterally in the lateral superior olive (LSO), bilaterally in the medial superior olive (MSO), and contralaterally in the ventral nucleus of the lateral lemniscus and in the lateral part of the central nucleus of the inferior colliculus. Degeneration was found in the contralateral medial nucleus of the trapezoid body when the lesion included the interstitial cochlear nucleus. Small lesions in anterior AVCN produced degeneration in both MSO and LSO, but after small lesions in posterior AVCN there was little or no degeneration in MSO. These results suggest that the projection to MSO originates in the anterior part of AVCN. [Supported by a grant from the National Science Foundation.]
Saturation of amplitude fluctuations of sound propagating through turbulence on vertical atmospheric paths
Authors: Brown E. H. , Clifford S. F.
Published: October 2005

A recent paper [S. F. Clifford, G.R. Ochs, and R.S. Lawrence, “Saturation of optical scintillation by strong turbulence,” J. Opt, Soc, Am, 64, 148–154 (1974)] provides a physically based theory which accurately predicts saturation of the log-amplitude variance of the amplitude fluctuations of waves propagating through strong turbulence. The present study extends the results of the theory to sound propagating over a vertical atmospheric path for which the intensity of the refractive index fluctuations varies strongly and systematically over the path. The theoretical results include some interesting new effects which may prove useful, both for studying atmospheric structure, and for studying acoustic propagation in random media. In particular, the latter includes a possible measure for the importance of “multiple scatter” with respect to “single scatter” for arbitrarily small amounts of saturation.
Excitation of a Helmholtz resonator under a turbulent boundary layer
Authors: Panton R. L. , Miller J. M.
Published: October 2005

A zero-pressure-gradient boundary layer on the fuselage of a glider was used to excite a Helmholtz resonator. The resonator was constructed so the orifice was flush with the surface. Nominal resonator frequencies were chosen so they would tune with different portions of the boundary layer wall pressure spectrum. The resonators were excited at both the Helmholtz frequency and a standing wave frequency. The results show a shift in the Helmholtz frequency when the boundary layer is present. This shift indicates the degree to which the turbulence interacts with the acoustic motion in the orifice and modifies the end correction. In several cases extremely high cavity responses were observed. These cases produced measurable sound in the free stream. The existence of this phenomenon correlates with the parameter ωd/u* (ω = resonance frequency, d = orifice diameter, u* = friction velocity). [This work was supported by NASA Ames Research Center.]
Amplification, attenuation, and dispersion of sound in inhomogeneous flows
Authors: Kentzer C. P.
Published: October 2005

First-order effects of gradients in nonuniform potential flows of a compressible gas are included in a dispersion relation for sound waves. Two nondimensional numbers, the ratio of the change in the kinetic energy in one wavelength to the thermal energy of the gas and the ratio of the dilatation frequency (rate of expansion per unit volume) to the acoustic frequency, play the dominant role permitting the separation of effects of nonuniformity into isotropic and anisotropic effects. Modification of ray acoustics for effects of flow gradients is suggested and conditions for amplification and attenuation of sound are discussed. [Research supported in part by NASA Grant NGR 15-005-174.]
Statistical-dynamical model of wind-generated air/water interfaces
Authors: Middleton David
Published: October 2005

A new statistical-physical model is constructed for deep-ocean surface gravity waves in fully developed, directional wind-generated seas and analogous air/water interfaces. Basic assumptions are that surface elevation and velocity jointly form a Markoff process and that the Langevin equation describing surface motion at a point is that of a (linear) under-damped harmonic oscillator driven by a Gaussian wind-forcing term. Surface elevation and velocity are then jointly normal random processes, with explicit point covariance and spectra. From these, directional covariances and surface wavenumber spectra are obtained. Although the model is linear, and thus approximate at the high wavenumbers (breaking waves, etc.), agreement with experiment to date is good to excellent for both the second-order moments and (first-order) probability distributions. Furthermore, the model exhibits the required ν−4 falloff of directional spectra with high surface wavenumbers, and permits “dc” wave impulses, e.g., tsunamis, tidal bores, etc. Swell and capillary waves are handled similarly. These results are important in underwater acoustic scattering from water/air interfaces (e.g., sonar, communications applications), as well as for EM and acoustic scattering from air/water surfaces and oceanography. [Work supported by the Office of Naval Research, Code 412.]
Signal detection: pre-stimulus change effects
Authors: Pastore R. E. , Puleo J. S. , MacLatchy C. S.
Published: October 2005

In a recent series of experiments [i.e., R. E. Pastore and C. S. MacLatchy, J. Acoust. Soc. Am. 56, S45(A) (1974)] we demonstrated that a post-stimulus decrease (15 dB) in the spectrum level of an otherwise continuous bandlimited (360–3360 Hz) masking noise had a small (2–6 dB), consistent, “backward masking” effect on the signal (20-msec segment of a 1000-Hz sinusoid). This paper describes a set of experiments which investigate the importance of stimulus change on an identical signal The change is a shift in the centroid of the masking noise (100 to 1400 Hz, or 600 to 1900 Hz) without altering either the total power of the noise or spectrum level of the noise within the frequency region of the signal (600 to 1400 Hz). [This research was supported by grants from NINDS and from the SUNY Research Foundation.]
Suppression at high frequencies
Authors: Shannon R.
Published: October 2005

Suppression of forward masking has been reported by T. Houtgast [Acustica 29, 168–179 (1973)] and by R. Shannon [J. Acoust. Soc. Am. 55, S32(A) (1974)]. The threshold of a sinusoidal signal was measured when the signal followed a 500-msec masker of the same frequency, fp. Then another sinusoid at frequency fv was added to the masker. When fv ≈ 1.2fp, the signal became easier to hear, i, e., the masked threshold of the signal decreased. We call this effect “suppression.” In the present experiment the frequency of the signal was 0.5, 1.0, 2.0, 4.0, or 6.0 kHz, with durations 40, 20, 10, 5, or 3 msec, respectively. Three subjects were run with signal frequencies 0.5, 1.0, and 2.0 kHz. Suppression was observed at all these frequencies for all three subjects. Two subjects were run with signal frequencies 1, 2, 4, and 6 kHz. Suppression was observed for both subjects at 4 and 6 kHz. However, one subject did not show suppression when the signal frequency was 1 or 2 kHz. When fp > 0.5 kHz, all of the forward masking patterns had similar shape in log frequency. Suppression is observed at frequencies higher than those at which phase locking occurs. Thus, suppression is not related to the phase-locking behavior of single neurons and may be mechanical in nature. [This research was supported by the National Institutes of Health.]
Receptor potentials in lateral-line canals
Authors: Boston J. R.
Published: October 2005

The receptor cells of the lateral-line organs of fish are very similar to cochlear hair cells and provide an easily accessible preparation that can be used as a model of the cochlear transduction process. There is a difference in the electrophysiology of the two situations, however, in that the receptor potential observed in the lateral-line canals in response to sinusoidal stimulation is a second harmonic of the stimulus, rather than the same frequency. Flock [Acta Otolaryng. Suppl. 199 (1965)] has presented a theory, supported by anatomical evidence, to explain this difference; the theory also implies that the receptor potential should grow as the square of the stimulus and that a dc component should be observed. The purpose of the present investigation is to describe quantitatively the receptor potential in the lateral line and to determine the relation between this potential and the cochlear microphonic. Input-output functions for the second harmonic response are presented, and the behavior of a dc component is described. These results are in agreement with Flock's theory.
Frequency dependence of tone-burst-generated whole nerve action potentials
Authors: Özdamar Özcan
Published: October 2005

At high sound-pressure levels, whole nerve action potentials (AP) elicited by tone burst, have been said to be generated by the click-like action of the onset of the bursts. The contrary opinion, that the AP is frequency dependent, has also been voiced. By using high-pass noise and tone-on-tone masking, tone-burst-elicited APs can indeed be shown to be highly frequency specific. In fact, by changing the cutoff frequency of masking noise, it is demonstrated that only a specific region on the basilar membrane, corresponding to the frequency of the tone burst, contributes to AP. As the frequency of the tone burst is changed, the masking curves shift accordingly. Tone-on-tone masking confirms these results by generating curves that are similar to the ones found in human psychophysical masking experiments. These findings might prove valuable in human electrocochleography where the use of high-intensity tones is desirable for obtaining better signal-to-noise ratios. [Supported by grants from NIH.]
Effects of anesthesia on the latency of the early components of click-evoked potentials
Authors: Bobbin R. P. , May J. G. , Lemoine R. L.
Published: October 2005

The latency-intensity functions of two short latency (<5 msec) components (N1;N4) of click-evoked potentials were recorded from scalp electrodes in paralyzed and artificially respired hooded rats. Recordings of 256 average responses were obtained before and 30 min after intraperitonial injections of saline, ketamine (100 mg/kg), and sodium pentobarbital (50 mg/kg). Although both ketamine and pentobarbital significantly decreased heart rate and altered the gross EEG, there were no significant differences in the latency-intensity functions of the two evoked-potential components. These results concur with previous findings of others for pentobarbital and halothane anesthesia [D. L. Jewett and M. N. Romano, Brain Research 36, 101 (1972)].
Application of parametric arrays to shallow water propagation
Authors: Clynch J. R. , Muir T. G.
Published: October 2005

The excitation of discrete modes of propagation by the use of narrow-beam, side-lobe free parametric arrays was investigated experimentally and theoretically. The Green's functions for excitation of normal modes by parametric arrays were studied analytically, and evaluated numerically for the present experimental configuration. Experimental results are interpreted in light of these excitation functions. The experiments were performed in a shallow area of a tank 8 m long and 11.4 cm deep at a frequency of 200 kHz. The energy coupled to a given mode was found to be dependent on the orientation of the parametric beam, the eigenray angle of the mode, and phase effects at the reflecting boundaries. Criteria for the realization of selective modal excitation are presented. Measurements of the sound pressure at mid-depth as a function of range and of projector orientation in the vertical plane, as well as depth profiles, were made. In the parametric case, an undistorted pulse, propagating predominantly in the first mode, was observed. Using titanium reflectors at both ends of the plate, undistorted parametric pulses were observed after as many as 22 reflections, which corresponds to a folded propagation range of 180 m. [This work supported by the U. S. Navy Office of Naval Research.]
Signal variation in a random medium
Authors: Grace O. D.
Published: October 2005

The acoustic ray-wave synthesis [O.D. Grace “Acoustic Ray Wave Synthesis,” NUC TP 408 (June 1974); J. Acoust. Soc. Am. 55, S83 (1974)] is applied to the problem of signal variation in a random medium. The problem is found to separate naturally into three regions which are designated nearfield, intermediate field, and farfield. In the nearfield region the field is predominantly the ray solution and the coefficient of signal variation is found to be as given by P.G. Bergmann [“Propagation of Radiation in a Medium with Random Inhomogeneities,” Phys. Rev. 70, 486–492 (1946)]. In the intermediate field region the scattered field becomes more important and the coefficient of signal variation is as given by D. Mintzer [“Wave Propagation in a Randomly Inhomogeneous Medium. I,” J. Acoust. Soc. Am. 25, 922–927 (1953)]. In the farfield the field is shown to be a zero mean Gaussian random variable with a Rayleigh distributed envelope and the coefficient of variation saturates at a value of unity. The expressions for the coefficient of signal variation in the three regions define a function of range and frequency and plots of this function represent the coefficient of signal variation as a surface.
Acoustic spatial correlation and random oceanic fluctuations
Authors: Moseley W. B.
Published: October 2005

The spatial correlation of a low-frequency acoustic wave which has propagated through an oceanic medium with random fluctuations in the sound speed is examined from the point of view of beam patterns and array performance. The nature of the temperature component of the sound-speed variability is described together with a general Bethe-Salpeter equation for the acoustic field correlation function. Comparisons are made between a theoretical solution for the transverse acoustic correlation and archival measurements. The qualitative nature of the variation of the correlation with range, receiver separation, and frequency are shown.
Low-frequency attenuation in the Pacific Ocean
Authors: Mellen R. H. , Browning D. G.
Published: October 2005

There is increasing evidence that the low-frequency sound absorption in the Pacific is less than that in the Atlantic. Thorp's original empirical equation was based largely on North Atlantic data. The origin of his excess attenuation anomaly has recently been identified as a boron relaxation. A compilation of available Pacific data appears to show roughly one-half the boron absorption predicted by Thorp, which suggests differences in the chemistry of the oceans.
Flow-induced transients and dynamic analysis of nuclear piping systems
Authors: Pedell M. H. , Nieh L. C. S.
Published: October 2005

Incidents of piping motion caused by flow-induced transients are common in nuclear power-plant systems. These flow-induced dynamic loads are classified as occasional loads in ASME Pressure and Boiler Code, Section III, which ought to be considered under applicable Normal/Upset, Emergency and/or Faulted conditions. This paper presents recent developments and the state of art in the area of fluid transients and piping dynamic analysis. Numerical computation methods are based on theories of unsteady fluid dynamics for solutions of forcing functions, with considerations made of control-system transients, dynamic behavior of prime movers and fluid machineries, and time-dependent characteristics of piping components. The dynamic responses, including stresses and reactions in piping systems, are evaluated by performing a time-history piping dynamic analysis using the calculated forcing functions. Illustrative examples include a main steam piping system under turbine trip load, a feedwater system under pump-failure condition, a closed safety relief system under steam blowdown lead, and an emergency core cooling system under pump start-up loads.
Earthquake protection for pneumatically actuated critical controls in nuclear power-generating stations
Authors: Randorff J. E.
Published: October 2005

The natural frequencies for piping system components have been calculated for pneumatically controlled equipment which is classified as “… essential to the safe shutdown and isolation of the reactor or whose failure or damage could result in significant release of radioactive material.” The objective was to assure that no coincident resonant conditions could be established due to excitation from an earthquake input. The intent of these theoretical investigations was to insure compliance with the seismic criteria as set forth by the IEEE Standard 344-1971. The standard allows for either mathematical or experimental verification. Mathematical techniques are generally preferred by suppliers and contractors whenever possible. This, of course, means that there will exist some necessary over-design, which is generally more acceptable than the trial-and-error required to interchange materials and physically re-test for optimum performance. The basic approach and techniques should be considered valid for systems of piping which occur in situations other than nuclear power-plant applications.
Experiments on acoustic resistors
Authors: Hillery H. V.
Published: October 2005

It is well known that the longitudinal-wave mechanical input impedance of a semi-infinite straight lossless rod and the electrical input impedance of a semi-infinite lossless electrical waveguide are both pure resistances. A short length of electrical waveguide can be terminated in a small noninductive, noncapacitive, electrical resistor of appropriate resistance to make its input impedance identical to the input impedance of a semi-infinite waveguide. Presumably, then, it should be possible to terminate a short rod in a nonreactive acoustic resistor and thus make the rod's input impedance identical to the input impedance of a semi-infinite rod. Experiments conducted to discover whether solid and liquid materials can be assembled into acoustic resistors similar in performance to electrical resistors have been fairly successful, The resultant devices absorb a high proportion of the acoustic energy incident on them from an acoustic waveguide and exhibit essentially resistive input impedances over a wide band of audible frequencies, The dimensions are much smaller than the wavelengths on the rod. [Work supported by the National Sciences Foundation.]
Survey technique for high-resolution ocean navigation
Authors: Durham J. L. , Spindel R. C. , Porter R. P.
Published: October 2005

We have reported on an acoustic Doppler navigation system for ocean use in several publications [R. P. Porter, R. C. Spindel, and R. J. Jaffee, J. Acoust. Soc. Am. 53, 1691–1699 (1973); R. C. Spindel, R. P. Porter, and R. J. Jaffee, J. Acoust. Soc. Am. 56, 440–446 (1974)]. The system can yield navigation fixes with respect to a bottom-moored, continuous-wave, beacon net with accuracies (on a fix-to-fix basis) of a few centimeters. The system has found use in generating synthetic space-time acoustic apertures where it is necessary to track a receiver to within a fraction of an acoustic wavelength. In order to use the system to best advantage, a survey is required to determine precisely the relative positions of the beacons forming the net. We report here on a navigation system that combines a pulse transponder with a beacon to improve survey accuracy. It measures acoustic travel time between survey platform and mooring, as well as accumulated phase between survey points. Nonlinear regression techniques are employed to develop a maximum-likelihood estimator for mooring positions. An approximate covariance matrix of the estimate errors is generated, and an optimum choice of survey points is indicated. The combined system, using these selected locations for performing the survey, yields mooring coordinate errors of about ±1 m. Improved precision appears to be limited by inaccuracies in the pulse and Doppler measuring systems.
Vowel harmony in Montreal French
Authors: Yaeger M.
Published: October 2005

This paper investigates some systematic properties of the French phonological system spoken in Montreal. The vowel system has a set of late rules, producing vowel harmony among all/syllabic units within a breath group. Analysis of the corpus-120 spontaneous-style interviews of all social strata of the Montreal-French-speaking community, collected by Cedergren and Sankoff—reveals that a vowel's F2 is influenced by the F2 of the succeeding vowel, which in turn has been influenced by the F2 position of the vowel which follows it, For English vowel systems studied to date, even task-oriented discourse, the primary coarticulation is between the vowel and its surrounding consonants; however, for these data, all systematic coarticulatory constraints obtain among the unstressed vowels which occur within one breath group. In addition, the transition from the nucleus is directed toward the nucleus of the succeeding vowel rather than toward the locus of the intervening consonant. [Work supported by SSRC of Canada, and Canada Council.]
Influence of intense noise exposure on masked pure-tone thresholds
Authors: Parker D. E. , Tubbs R. L.
Published: October 2005

Change in masked pure-tone detector thresholds as a function of intense noise exposure is of interest for both theoretical (neural coding) and practical (damage assessment) reasons. Thresholds for detection of a 3000-Hz tone embedded in a 2125- to 4250-Hz octave band of masking noise were determined before and after intense noise exposure. Masking noise levels were varied from 0 to 45 dB SPL. The intense noise was a 1200- to 2400-Hz octave band of white noise set at intensities of 90, 100, or 110 dB SPL. Each observation consisted of the following parts: (1) pre-intense noise exposure threshold determination, (2) 3-min exposure to intense noise, (3) 90-sec delay, and (4) post-intense noise exposure threshold determination. The results of a series of observations employing the above procedure indicate that pure-tone thresholds were elevated following the intense noise exposure by 4 to 9 dB when the tone was embedded in 0-dB masking noise (TTS2=4 to 9 dB), However, pure-tone detection thresholds were elevated following intense noise exposure by only 0.5 to 3 dB when the tone was embedded in 25- to 45-dB masking noise. Possible neural mechanisms that might account for these observations are considered. [Work supported in part by U. S. Air Force Contract F33 615 73C 4002.]
Coarticulation in VCV and CVC utterances: some EMG data
Authors: Bell-Berti F. , Harris K. S.
Published: October 2005

The extent of coarticulation is of central interest to theories of speech production. Knowing the anticipatory and carryover limits of coarticulation will allow us to specify the constant features of a set of speech sounds. Most earlier work has reported on observations of the articulator movement or acoustic result of coarticulation [e.g., B. E. F. Lindblom, J. Acoust. Soc. Am. 35, 1773–1781 (1963); S. E. G. Öhman, J. Acoust. Soc. Am. 39, 151–168 (1966); P. F. MacNeilage and J. L. DeClerk, J. Acoust. Soc. Am. 45, 1217–1233 (1969); R. Daniloff and K. Moll, J. Speech Hear. Res. 11, 707–721 (1968); T. J. Gay, J. Phonetics 2, 255–266 (1974)], The present study is an attempt to define the extent and effects of coarticulation on EMG activity recorded from the tongue and lips for VCV and CVC utterances, and to correlate this activity with the resulting acoustic signal. Preliminary results suggest that carryover effects are more extensive than anticipatory effects. [Supported by NIDR Grant DE-01774.]
Acoustics aspects of French nasal vowels
Authors: Mrayati M. , Carré R.
Published: October 2005

The characteristics of French nasal vowels in the case of various CVCV combinations are studied. A set of CVCV utterances was read by 10 speakers (five males and five females) and analyzed using predictive coding techniques. The consonant C consisted of voiced stops, unvoiced stops, nasal consonants… while the vowel V was one of four nasal French vowels (/ɛ̃/, /ɑ̃/, /ɔ̃/, /œ̃/). Vowel acoustics features such as formants and bandwidth frequencies, intensity, fundamental frequency, and duration are studied. Most of the results obtained are in accordance with the acoustic theory. Differences between nasal and nasalized French vowels seem significant and the French nasal vowel characteristics seem as stable as those of the oral vowels. Application to speech synthesis and recognition is discussed.
Simple model for parametric source beam patterns
Authors: Moffett Mark B. , Mellen Robert H.
Published: October 2005

By logical extension of a previous model for the prediction of parametric transmitter source levels, a simple formula for parametric source beam patterns has been derived. In this approach, the beam pattern may be easily calculated from a knowledge of the magnitude and phase of the parametric “gain” (i.e., the complex ratio of the secondary and primary source levels). Some problem areas remain, however, and these are outlined.
Vibrational modes of membranes and plates of a variety of shapes
Authors: Worman W. E.
Published: October 2005

The linearity of the equations of motion for small amplitude vibrations of plates and membranes allows new solutions of the equations to be constructed from known solutions by superposition. In particular, for an infinite membrane or plate, a new solution can be formed by taking a known solution, displacing it, and then adding it to the undisplaced solution. For example, since y1 = AJ0(k|r⃗|)e−iωt is a solution for an infinite membrane, so is y2 = A[J0(k|r⃗|) + J0(k|r⃗ + a⃗|)]e−iωt for any a⃗ in the plane of equilibrium. The membrane can then be considered clamped along any closed nodal line and the portion outside the line disregarded. The solutions constructed from “displaced” standard solutions are useful in understanding the modes of vibration of membranes and plates of a variety of shapes. Hopefully, they can provide a basis for perturbation calculations. Constructions have yielded enticing suggestions of relations between mathematical functions. Most work to date has been with Bessel function solutions, but other solutions, such as those using the cylindrical functions, can also be combined.
Monaural auditory adaptation as measured by simple reaction time
Authors: Davis J. M. , Weiler E.
Published: October 2005

Pre- and post-reaction time measures were compared following 7 min of monaural auditory adaptation. The adapting stimulus utilized was a 500-Hz pure tone presented at an intensity level of 50 dB SPL for a period of 7 min. The pre- and post-adaptation reaction time measures were obtained for the frequencies 400, 8000, and 10 000 Hz at intensity levels of 50, 60, and 70 dB SPL. The results revealed a significant increase in the post-adaptation reaction time measures for all of the frequencies and intensities tested and would suggest that reaction time measures can be utilized in the study of auditory adaptation phenomena.
Mathematical modeling of cochlear electrical activity and its possible applications to a diagnostic methodology
Authors: Biondi E. , Dacquino G. , Grandori F.
Published: October 2005

The possibility of evaluating the contributions of any single Corti organ zone to the compound activity (cochlear microphonic, summating potential , and action potential) seems to be a constructive step toward a better knowledge of the system itself and, for the prespectives it offers, toward a refinement of objective audiometry by electrocochleography. In this paper the definition of basilar-membrane zone is given to the portions of Corti organ, any single point of which can be considered to be subjected to almost equal displacements. Then the concepts of an equivalent receptor and of an equivalent fiber are introduced, defined as those elements whose outputs respectively account for (i) the compound electrical activity of the entire set of closely neighboring auditory receptors belonging to the same Zone, and (ii) the contribution to the compound action potential of the set of fibers innervating the hair cells of the Zone. Remarkable agreement has been found between the model predictions and the experimental data.
Environmental noise impact assessment
Authors: Carlson J. P.
Published: October 2005

A case example of environmental noise impact determination is presented. Environmental noise impact is based on estimated community noise changes from facility operation and construction. These changes are used to estimate incremental community reaction. Methodology consists os comparing average day-night A-weighted sound level (Ldn contours for facility emissions, the present community environment, and their combination. Estimates of sound level and land area impacted are developed to describe community noise changes. Natural and mechanical draft cooling tower impact on nearby communities were compared.
Some specific characteristics of vibration pickup type auditory canal microphones
Authors: Miyawaki Yoshinori , Mori Shinsaku , One Hiroshi , Saito ShigeJi
Published: October 2005

In high-noise environments, we cannot sufficiently transmit voice signals by the usual transducers. Therefore, we have developed a vibration pickup-type microphone (acceleration type) and propose that communications be exchanged using this method. We chose the auditory canal in order to equip this microphone easily. In this investigation, we (1) compared a vibration pickup-type auditory canal microphone with a noise-canceling microphone focusing on their ability to shut noise out; and (2) compared an air-conduction spectrum caught by a handy microphone with a bone-conduction spectrum caught by the vibration pickup-type used in Experiment 1. When subjets pronounced the vowel /a/ with a vibration pickup-type microphone, the ability to shut noise out increased 5 to 9 dB when compared with a noise-canceling microphone. If the subjects put on earmuffs, the ability to shut noise out increased 6–10 dB. According to the results of Experiment 2, the response decreased in the high frequency beyond 1 kHz. This might be caused by the dumping of bone conduction, We then tried to make an equalizer in order to produce a more natural voice by revising the high-range dumping.
Cross-linguistic study of categorical perception for lexical tone
Authors: Chan Stephen W. , Chuang Chiu-Kuang , Wang William S.-Y.
Published: October 2005

This paper reports on tone perception by Chinese and American subjects and presents evidence that tones are perceived categorically by tone language speakers. Subjects were asked to identify and discriminate (ABX) synthetic speech stimuli which varied in acoustically equal steps through a range sufficient to produce the Mandarin “rising” and “level” tones. Chinese subjects showed a categorical boundary located near the middle of the stimulus space, i.e., there is a good correspondence between the crossover points in the identification functions and the peaks in the discrimination functions. American subjects exhibited a boundary closer to the level tone; this may be due to perception in a psychophysical mode. When tested on nonspeech stimuli having the same F0 characteristics, Chinese subjects showed a similar categorical boundary. Trained Chinese subjects having comparatively small JND for tones tend to perceive the stimuli only psychophysically. It would be of interest to determine if the acoustical distance between stimuli is sufficiently decreased for the discrimination task, and whether these subjects would also show a more prominent peak in their discrimination functions indicating categorical perception for tone. [Work supported by NSF, Grant no. SOC-05798A01.]
A distance-sensing device for tracking tongue configuration
Authors: Chuang Chiu-Kuang , Wang William S.-Y.
Published: October 2005

An artificial palate implanted with a photoelectronic distance-sensing unit has been devised for tracking the continuous movement of the tongue surface during speech activities. A pair of narrow angle light source and photo sensor, imbedded in a 13.0x7.5x3.3 mm plastic base, has been studied experimentally in detecting the distance of a moving object by sensing the reflected light; this method has proved to be particularly effective when the object reflects with a nonsmooth surface. By arranging from four to seven units of this device along the midsagittal line of the hard palate, a real time displacement of the tongue surface can be reconstructed and displayed on the CRT. A preliminary device has been used to study the coarticulation between various consonants /p, t, k, l, n/ and vowels /i, e, a, o, u/. We have checked our data against earlier reports on coarticulation based on x-ray studies (Perkell). While the two types of results are comparable, the new device is simple in construction and allows the experiments to be free from the hazards of x-ray exposure. [Work supported by NSF, grant no. SOC-05798A01.]
Sentence prosody in isolated and in story contexts
Authors: Nakatani Lloyd H.
Published: October 2005

Isolated sentences read from a list are often used as test material in speech experiments. But if isolated sentences differ noticeably from the same sentences read in a story, then the generality of observations on isolated sentences is severely restricted, and the construction of test material which permit broader generality is troublesome. To see if isolated and story sentences were perceptually distinguishable, listeners were presented with stories read normally and stories spliced together from sentences read from a randomized list. The listeners had difficulty identifying the stories as normal or spliced. This and other results affirm that speech features observed in isolated sentences can be reasonably generalized to sentences in a coherent context.
Dialect variation in pitch contours on stressed syllables
Authors: O'Malley M. H. , Yaeger M.
Published: October 2005

The pitch contour is often considered to be an important signal, if not the principal acoustic signal, of linguistic stress. While it has been recognized that pitch dips as well as pitch rises can indicate stressed syllables, stress detectors for automatic speech recognition systems have often been based on the detection of pitch rises. The present experiment measured pitch contours on stressed syllables for speakers of several dialects. Both formal and informal styles of speech were used. It was found that the use of pitch contours to signal stress is a function of dialect. In particular, there exist dialects for which duration or amplitude rather than pitch is usually the cue for stressed syllables. The results of this experiment are further evidence that dialect variation and speech style must be considered in studies of the acoustics of speech.
Measurement of the ambient noise horizontal directionality in the ocean with a circular superdirective array
Authors: Bird J. S.
Published: October 2005

This paper describes the degree to which the horizontal directivity of the ambient noise in the ocean may be characterized using a six-element circular superdirective array and a pressure-gradient beamform technique. The approach used is to model the noise field as a Fourier series and to consider the array as acting like a low-pass filter in the spatial frequency domain. The effect of the beam pattern on the noise field is calculated exactly and a method developed to remove this effect, except for bandlimiting in the spatial frequency domain. A method to reconstruct a time-averaged representation of the noise field that is continuous in the horizontal plane even though the array used a discrete number of beams is developed. Using field data, it is shown that the magnitude and phase of the noise field coefficients may be used to make conclusions about noise mechanisms and to indicate the presence of discrete noise sources.
Passenger noise environments of enclosed transportation systems
Authors: Konheim Ag. G. , Ruth J. S.
Published: October 2005

To determine the extent to which noise environments of enclosed transportation systems are deleterious to passenger health, an analysis was made of both information collected by past transportation studies and of new data collected for this project. The analysis consisted of identifying trends among various transportation modes, noting areas of data deficiency, calculating the effect of noise exposure on health under various assumptions of travel duration and work-place noise exposure levels, and assessing measurement methodologies. A follow-up program to collect exposure data through the use of noise dosimeters is discussed.
Initial acoustic assessment of the Bay Area Rapid Transit System
Authors: Porter Michael A.
Published: October 2005

The Bay Area Rapid Transit System (BART) represents this country's first new, state-of-the-art fixed guideway rapid transit system. The data obtained from analysis of this operational system should prove to be of major benefit to the design and construction of future systems elsewhere. The results of this initial phase of an acoustic analysis of the BART system provides an indication of the quantity and quality of the information that will be available for use in the design of future systems. The emission levels of BART operations under various configurational and operational modes presented and noise exposure levels due to BART in the community are discussed.
Acoustic impulse studies of radiation from liquid-solid interfaces
Authors: Caroine E. F. , Fritsch K. , Ursic J. J. , Burke L. C.
Published: October 2005

A modified technique has baen daveloped for laboratory studies of acoustic radiation from solids submerged in liquids. Plane and cylindrical targets are irradiated with laser-induced acoustic impulses of the order of 0.1 μsec in duration. Schlieren optical and acoustic probe techniques are used to examine the resulting acoustic signals. Special consideration is being given to the excitation of surface waves on the liquid-solid interface. The short duration of the incident acoustic impulses makes it possible to detect effects that may be less apparent in data obtained with pulsed sinusoid or continuous-wave techniques. [Supported in part by the Office of Naval Research.]
Elastic wave scattering from spherical cavities
Authors: Tittmann B. R.
Published: October 2005

Recent theoretical and experimental results on the scattering of ultrasonic pulses from a single spherical cavity embedded in a metallic solid will be reviewed. Except at high frequencies, the data are in reasonable agreement with theory, bearing out the notable features predicted for the angular dependence and mode conversion between longitudinal and transverse waves. At high frequency, the disagreement could be accounted for by the lack of monochromicity in the short-duration ultrasonic pulses used. Methods were developed of calculating the high frequency results by synthesizing the scattered wave packet out of each of the frequencies making up the incident pulse. In this context the angular dependence of the scattered rf waveform and its Fourier transform are also discussed. [This work was partially supported by AFOSR Contract No. F44620-74-C-0057 and ARPA-AFML, Contract No. F33615-74-C-5180.]
Measurement from the nearfield of an ultrasonically produced phase grating
Authors: Cook B. D.
Published: October 2005

The optical irradiance in the nearfield of a sinusoid phase grating is a complex pattern exhibiting certain symmetries and periodicities. A simplified expression for this irradiance has been developed. Application of this expression to an ultrasonically produced phase grating permits interpretation of file perimental data for the magnitude of the retardation (Raman-Nath parameter) and location of the phase grating. This technique is applicable to pulsed ultrasonic waves and can be used for acoustic pressure and power measurements, both peak and average. [This research was supported by the Bureau of Radiological Health, FDA.]
Ultrasonic dynamic gas flowmeter for medical applications
Authors: Draegerwerk H. Frankenberger , Häusler E. , Kiefer R.
Published: October 2005

The principle of a dynamic flow measurement device is described, which allows the measurement of gas flow in the range of 1 to 150 1/min with time resolution of 1 msec. With two ring-shaped transducers, the delay time upstream and downstream of ultrasonic pulses in the upper kilohertz and megahertz range is measured. In a process computer, the differences of the reciprocals of these values are obtained. These differences are proportional to the flow, not dependent on gas composition and temperature. For measurements with CO2 (and other 3-atomic gases) air mixtures, the influence of the rotational absorption must be considered. This requires lower ultrasonic frequencies and greater lengths of the measuring path. The time resolution of the flowmeter is therefore reduced. First experimental results are presented.