bluuebunny/crossref_metadata_2025 huggingface dataset:
The effects of exposure to noise on cochlear potentials and potassium ion activity in guinea pigs
Authors: Salt A. N. , Konishi T.
Published: October 2005

The acute physiological changes in the cochlea which accompany noise overexposure have not been well documented to date. In the current study the cochlear microphonics (CM), action potentials (AP), endocochlear potential (EP) and endolymph potassium activity were recorded continuously using double barreled ion selective electrodes. The input/output functions of the CM and AP in response to 6-kHz tones were measured in the period between successive exposures. It was found that exposure to 115 dBA noise, which was sufficient to reduce considerably the sensitivity of the CM and AP responses, resulted in an increase in the EP whilst no change in the endolymph potassium activity was observed. The supernormality of EP was not observed when preparations in which the cochlear hair cells had been damaged by treatment with kanamycin were subjected to the same exposure level. Our data support the view that the reduction of cochlear sensitivity resulting from acute noise exposure is due to changes at the level of the hair cells rather than the stria vascularis.
Behvior of tone-induced cochlear responses to potassium concentration elevated by scala tympani perfusion and monitored by ion-sensitive electrodes
Authors: Salt A. N. , Stopp P. E.
Published: October 2005

Guinea pig scala tympani was perfused with modified Ringer's solutions containing potassium (K+) from 5 to 50 mM; tone-induced cochlear responses were monitored before, during and after perfusions. The N1 and afterpotential amplitudes were most noticeably reduced, especially from concentrations of 20 mM K+ upward. SP amplitude was variable, but with 13–20-mM K+ showed a consistent change in onset shape. CM amplitude was least affected, not showing any significant reduction even at 35 mM. At 50 mM, the highest concentration used, the reduction in CM was about 30%. These results differ from previous work [Tasaki and Fernández, J. Neurophysiol. 15, 497–512 (1952)], which reported almost complete suppression of CM with 33 mM K+.
Electrical potentials within the organ of Corti in guinea pigs
Authors: Tanaka Y. , Asanuma A. , Yanagisawa K. , Katsuki Y.
Published: October 2005

DC potential and microphonic responses to sound stimuli were recorded in electrode penetration to the organ of Corti in guinea pigs. Recording sites of potentials were identified by a new marking technique using the dye, Alcian Blue. The resting potentials of Deiters' cells were between −45 mV and −95 mV. The resting potentials of outer hair cells were less negative than those of supporting cells. When the electrode was pushed very slightly, this resting potential tended to move towards positive values. The amplitude of microphonic potentials recorded inside the outer hair cells diminished in proportion to the decrement of their dc potentials. Depolarization of outer hair cells may relate to upwards displacement of the reticular membranes by an electrode.
Quantitative studies of the cat VIIIth nerve using a two-tone stimulus paradigm
Authors: Roth G. L. , Rhode W. S.
Published: October 2005

In the mammalian cochlea, primary fibers to inner hair cells synapse with one or a very few receptors, and thereby innervate only a restricted region, or point, on the basilar partition. In contrast, VIIIth nerve fibers innervating outer hair cells course toward the basal (high frequency) portion of the cochlea and then synapse with a number of receptors over a finite length of the basilar membrane. Because of these unique patterns of distribution, it seems possible that the two major afferent populations might respond differently to identical stimuli, if appropriate parameters are selected. In order to determine if these anatomical distinctions are reflected by physiological differences under a defined set of stimulus conditions, we have recorded the responses of a population of VIIIth nerve fibers in the cat utilizing a two-tone stimulus paradigm. In these experiments, f1 was placed at the fiber's characteristic frequency (CF), and a higher frequency f2 was systematically changed to explore in and around the high frequency suppressive region. Typically, two or three levels of f1 were presented and f2 was stepped from 20 dB below to 30 dB above f1 level. Response areas for each fiber were also obtained. Results of analyses on this population of fibers will be presented. [Work supported by NIH.]
Temporal properties of two-tone suppression: Phase-locking of high characteristic frequency auditory-nerve fibers to low-frequency tones
Authors: Sachs M. B. , Hubbard A. E.
Published: October 2005

Responses of auditory-nerve fibers with high characteristic frequency (greater than 5 kHz) to characteristic frequency (CF) tones can be suppressed by tones of much lower frequency. In such cases, the fiber responses are phase-locked to the low-frequency suppression tone, but not to the characteristic frequency tone. Such situations are ideal for studying the temporal properties of two-tone suppression. In this series of experiments, period histograms synchronized to the low-frequency suppressor are computed. As the sound pressure level of a low-frequency suppressor is increased (in the presence of a CF tone of constant level), phase-locking to the suppressor appears at levels below those which cause a decrease in average rate. The phase of the histograms is estimated by the phase of the fundamental component of the Fourier series for the histogram. Over the range of levels where two-tone suppression occurs, the histogram phase shifts until at high levels the phase is the same as the phase in response to the suppressor tone presented alone. That is, parts of the cycle of the suppressor tone which are excitatory at high stimulus levels can cause suppression at lower levels. [Supported by Grant No. NS12112 from NIH.]
Rate versus level functions for auditory-nerve fibers in cats: Bandlimited noise bursts
Authors: Schalk T. B. , Sachs M. B.
Published: October 2005

We will generalize our previous description of the responses to two-tone stimuli to allow the prediction of responses to continuous spectrum stimuli. For noise bursts of one bandwidth and center frequency, discharge rate was measured as a function of spectral level. Such rate-level functions were measured for a number of noise bandwidths; either the low- or high-cutoff frequencies were set at fiber characteristic frequency. Narrow bands of noise produce rate-level functions similar to those for CF tones. For noise bands centered above CF, rate-level functions become less steep as bandwidth is increased and approach the same saturation rate as that produced by CF tones. For wide bands of noise centered below CF, rate-level functions can be nonmonotonic or appear to plateau at rates less than the saturation rate to CF tones. Thus, bands centered either above or below CF can produce lower discharge rates than do narrow bands of the same spectral level. This rate reduction has properties similar to those of two-tone suppression. [Supported by NINCDS and NINGMS.]
The dynamic range of responses of single cochlear fibers in the cat to individual spectral components of comb-filtered noise
Authors: Natins P. M. , Evans E. F.
Published: October 2005

The discharge rates of single auditory fibers in the pentobarbitone anaesthetized cat were measured in response to comb-filtered noise (CFN) of continuously varying peak spacing and at different levels. The number of spectral peaks resolved by the cochlear nerve fibers in terms of their discharge rate, decreases, as does the magnitude of the response, with saturation of the rate response. The measured dynamic range over which the fibers were able to reflect, in their discharge rates, the spectral envelope of the CFN stimulus, varied between about 30–60 dB. This is consistent with the findings of Evans [in Psychophysics and Physiology of Hearing (Academic, London, 1977)], in which it was also shown that single cells in the dorsal cochlear nucleus were able to resolve spectral peaks of CFN over a wider range (in some cases in excess of 70 dB) than cochlear nerve fibers. The present study demonstrated that, in addition to these findings, the CFN dynamic ranges of many cochlear fibers, at least, were consistent with their rate-intensity functions for broadband noise.
Neural correlates of a signal detection task in the rabbit
Authors: Kettner R. E. , Thompson R. F.
Published: October 2005

Neural differences between hit and missed trials at a single threshold intensity were examined. First, the rabbits were classically conditioned to move their nictitating membrane to a white noise stimulus. The intensity of this stimulus was then reduced in a staircase paradigm until performance was near chance (“threshold”). During this performance, multiple units were recorded from the cochlear nucleus, inferior colliculus, medial geniculate, and hippocampus. Neural response averages were made of both the hit and the missed trials, and displayed as PST histograms. By far the largest differences occured in the hippocampus. It responded strongly on hit trials, and weakly or not at all during missed trials and under unpaired control conditions. In the auditory nuclei, the prestimulus mean was generally smaller and the onset response was generally larger during hit trials. Other response measures were calculated and then compared to the predictions of various models of signal detection. The possible sources of the above differences are also discussed. [Work supported by the McKnight Foundation, NSF Grant BMS75-00453, and NIH Grant NS12268.]
Research on low bit rate speech coding at the Electrical Communication Laboratory, NTT
Authors: Itakura Fumitada
Published: October 2005

Since the introduction of speech analysis—synthesis based on the maximum likelihood spectrum estimation—in 1966, we have been conducting research activities on low bit rate speech coding techniques, and their aplication to audio response and low bit rate digital speech transmission. Parcor analysis-synthesis, demonstrated in 1969, was one of the most fundamental methods, and it has formed the basis of the present development of linear predictive coding. Recently, various kinds of techniques have been proposed to improve speech quality, such as interpolation and nonlinear quantization of parameters, spectral smoothing, etc. They have been applied in the hardware realization of a 4 CH multiplexed 2400 bps Vocoder. At present, the Parcor method is being applied to a wide range of speech coding from 1200 bps variable frame-rate coding to high quality 16 kbps adaptive, predictive coding.
Ocean bottom seismograph (OBS) results for ocean acoustics
Authors: Nagumo S. , Kasahara J.
Published: October 2005

OBS observation of underwater explosion and natural earthquakes contributes in many respects to the ocean acoustics for understanding the nature of underwater sound propagation and acoustic properties of bottom sediments as well as subbottom structure. It was observed that T-phases were generated in a deep flat ocean basin by the earthquakes which occurred in the ocean crust. It is interpreted that the abyssal T-phase is generated by the diffraction wave at the oceanic basement (layer II) which is overlying very close to the shallow earthquake origin. The arrival phases of underwater sound from explosion source to the OBS in the long range propagation in a deep ocean generally contain very small onset phases. This is regarded as the limiting ray of RSR (Refraction Surface Reflected) rays. An advantage of using OBS is to obtain S-wave information. P-wave to S-wave conversion takes place very efficiently at the sea bottom as well as at the base of sediment layer. S-wave velocity in the bottom sediment (layer I) is very low, the ratio Vp/Vp ≑ 4 ∼ 3. The spectra of seismic noise upon the deep ocean floor decrease very rapidly above several Hz.
The measurement of bottom reflectivity at vertical incidence: A new instrument and an evaluation
Authors: Matsumoto Haruyoshi , Parvulescu Antares
Published: October 2005

We describe a new instrument for the collection of data on bottom loss and/or bottom reflectivity with standard hull-mounted bathymetric equipment. The bottom returns contain substantially more information about the nature of the bottom than is currently utilized—in the form by bathymetry—yet the possible use of this information has not received enough analysis. Our preliminary analysis, and the instrument devised to collect into the shipboard computer valid statistics about the returns, comprise our report.
Experimental studies of attenuation in sediments
Authors: Stoll R. D.
Published: October 2005

Recent theoretical work [R. D. Stoll, Geophysics 42 (4), 715–725 (1977)] indicates that attenuation in ocean sediments depends on two distinct types of energy loss; these losses result from inelasticity of the skeletal frame and motion of the pore-water relative to the frame. In this paper, experimental evidence is presented which verifies the response predicted by the theoretical model. Torsional resonance and logarithmic decrement are measured over a wide frequency range in both water-saturated and dry sediments. A change-over from dominance by one type of loss to the other is clearly demonstrated by a change of response that is observed as the frequency is varied. Special equipment is used which allows the intergranular stress to be controlled to simulate various depths of embedment in the sea floor. Both the theory and the experiments suggest that for some sediments, the attenuation will vary in a manner quite different from the usual dependency on the first power of frequency that is often assumed. [Work supported by ONR.]
Microcomputer applications in hearing conservation
Authors: Yonovitz A. , Mitchell C. W. , Lewis H.
Published: October 2005

The purpose of this study was to design, implement, and assess an efficient and economical microcomputer based system for audiological and hearing conservation applications within industrial environments. Current legislation requires accurate monitoring of the hearing acuity of employees who are at risk. Microcomputers can be of significant benefit in audiological assessment and hearing conservation by allowing paraprofessionals to carry out these testing procedures. Microcomputers can now accomplish complex data acquisition, analysis, storage, and retrieval. A microcomputer system also provides improved accuracy and record integrity. This is accomplished through, automatic data acquisition from commercially available audiological testing devices. Rapid retrieval of audiological records and numerical comparison of audiograms provide systematic disposition of employees within a hearing conversation program. The software algorithms and interfacing hardware will be described and a system demonstration will follow.
Cost-benefit analysis of three decision criteria for spondee threshold measurements
Authors: Chial Michael R. , Slater Mary E.
Published: October 2005

Although the clinical definition of the spondaic threshold (ST) is based upon a 50% performance level, many audiologists do not adhere to this criterion. This study investigated the relative merits of three criteria for the ST by means of a benefit-cost ratio (B/C) analysis procedure that considers test-retest reliability, accuracy, statistical efficiency, and the effort required to accomplish measurement. STs were obtained twice from normal listeners (N = 10), and from impaired listeners with moderately sloping (N = 10) or steeply sloping (N = 10) audiograms. A computerized procedure mimicked the currently favored clinical method for ST measurement. Threshold criterion was varied among 50% correct, 100% correct, and 50%–100% correct rules. Dependent variables included SPL at threshold, and the time and number of words required to accomplish measurement. B/C analyses revealed that for all three subject groups, threshold criteria could be rank-ordered from “best” to “worst” as follows: 50%–100% correct, 100% correct, 50% correct. These results agree with an earlier study of normal listeners by Chial, Beck, and Vanlandingham [J. Speech Hear. Res. 18, 105–114 (1975).
Investigation of the Tullio phenomenon in adult males
Authors: McLaughlin N. A.
Published: October 2005

The Tullio phenomenon, a nystagmus reaction elicited by sound stimulation, has been considered to signify congenital syphilis. The present study investigated the incidence and characteristics of the Tullio phenomenon in adult males not suspected of labyrinthine fistula or congenital syphilis. The specific variables of the Tullio phenomenon investigated were (1) incidence, (2) relationship to complaints of tinnitus or vertigo, (3) characteristics of sound stimuli most effective in its elicitation, (4) the relationship of the direction of the nystagmus reaction to the ear stimulated, and (5) the effect of spontaneous nystagmus on the direction of the nystagmus elicited by sound stimuli. The data indicates (1) the presence of the Tullio phenomenon in nonsyphilitic ears and in the absence of a known labyrinthine fistula is not as rare as has been previously believed and (2) in the presence of a spontaneous nystagmus, sound stimuli tend to cause an exacerbation of this preexisting nystagmus regardless of which ear is stimulated. This finding is in direct opposition to previous research which states that nystagmus resulting from sound stimulation, beats toward the stimulated ear. Diagnostic and physiologic implications are discussed.
An investigation of dual sensory stimulus presentation of complex noiselike sounds
Authors: Barbour Alfred
Published: October 2005

The ability of a subject to detect changes in auditory and visual signals was investigated. Subjects were presented auditory signals via headphones (A), a spectral representation of the signal via a CRT (V) or both representations simultaneously (AV). The signal pairs were bands of noise, buried in a noise. The amplitude of the signal increased slowly, allowing the SNR to increase slowly. This gave the signal the appearance of emerging out of the noise. The task of the subject involved determining which of two possible signals was presented in the noise and to respond by pressing a designated response button. Subjects were asked to use the criterion of reasonably certain of their choice. The subjects used were four college age students ranging in age from 20 to 26 years old, all were screened for normal hearing and near visual acuity. Subjects were chosen who had no prior experience with signal detection of auditory discrimination tasks.
Multidimensional analysis of timbres of complex tones
Authors: Ohgushi K.
Published: October 2005

In order to investigate the relation between physical parameters and timbre of complex tones, three-frequency complex tones were synthesized on a digital computer. Subjects made similarity judgments of pairs of the complex tones and the experimental data were analyzed by Kruscal's multidimensional scaling program. Recent investigation [J. R. Miller and E. C. Carterette, J. Acoust. Soc. Am. 58, 711–720 (1975)] shows that fundamental frequency, amplitude envelope and number of harmonics are important determinants of timbre. Therefore, the above three physical parameters were held constant in our study. That is, the complex tones had a fundamental frequency of 300 Hz, trapezoidal amplitude envelope with rise-fall time of 50 ms and three frequency components. Analysis of data showed that the lowest and the highest component frequencies were the most important physical parameters governing timbre of three-frequency complex tones. Furthermore, it was shown that time structures of tone waveform were factors governing timbre.
An application of digital techniques to obtain the spatial information of a room
Authors: Yamasaki Yoshio , Yamasuda Shigeru , Saitow Hiroyuki , Yasukawa Kenichiro , Itow Takeshi
Published: October 2005

The impulse response represents the transmission characteristics from the certain source point to the receiving point of the room, if we consider it to be a linear system. According to the position of the source and receiving points some differences are caused in the impulse responses, but they imply the spatial characteristics of the room. The mirror image method is often used to obtain the spatial characteristics of a room, but it is difficult to apply this method to an actual room because of the complexity of the room shape. At four slightly variant receiving points on x, y, and z axis, we measured the impulse responses of the same source point. Then we computed the image sources to the three dimensional field. From these virtual image sources, we obtained SPL distributions, conditions of standing waves, effects of absorbing materials, mean free path, etc., in a room.
Nonlinear acoustic torque in intense sound field
Authors: Wang T. G. , Kanber H.
Published: October 2005

Recently, a new method of generating controlled acoustic torque has been reported; a linear relationship between the acoustic torque and particle velocity on a cylinder was suggested [Phys. Rev. Lett. 38, 3 (1977)]. In this paper, we report the observed nonlinear relationship between the acoustic torque and particle velocity on a cylinder, and on a disk at the sound intensities beyond those reported in the reference cited. A theoretical model based on viscous penetration depth is discussed, and a comparison with experiment is given. [Work supported by NASA.]
On Japanese transverse flute
Authors: Ando Yoshinori
Published: October 2005

A kind of Japanese transverse flute “Nô-kan,” used in one of the most refined musical arts of Japan “Nô-gaku,” has a distinctive bore shape. The inside diameter between its mouthhole and the first tone-hole is narrowed by a short and small pipe, named “throat,” inserted tightly in its main pipe. The throat perturbs the octave relation between the first and second mode and causes discontinuity of harmonic structure between the two mode tones. These special features of a Nô-kan is quite contrary to the other kinds of flute such as the western concert flute, which has been improved to be tuned in equal temperament, and have uniform tone quality through a three octave range. The investigated quantities of structural dimensions and acoustical properties of a Nô-kan will be reported in connection with its musical function compared to the other kinds of Japanese flute and the wetern concert flute.
A striving toward equal temperament: Prince Tsai-yu in 1595 at Peking, and Simon Stevin shortly thereafter at Amsterdam
Authors: Mulder George W.
Published: October 2005

Did East meet West in 1595? Equal tempered approximations 1595, Peking and Amsterdam or the riddle of the abacus and logarithms. Both Tsai-yu and Stevin set down the mathematical figures for equal temperament. Tsai-yu calculated the 12th root of 2 by means of the abacus, carefully computing the appropriate root for each note separately—correct to nine decimals. Stevin's calculations on the other hand, finding 11 mean-proportional parts between 2 and 1, were based upon the 45th proposition of his French arithmetic.
In-service testing of rail transit noise control treatments
Authors: Wilson George Paul
Published: October 2005

As a part of the overall Urban Rail Supporting Technology Program, the U.S. Department of Transportation (DOT) Urban Mass Transit Administration (UMTA) has sponsored a program of in-service testing and evaluation of four noise control treatments applied to an existing rail transit facility. Rail grinding, wheel truing, resilient wheels, and damped wheels were applied to selected rail sections and vehicles of the Southeastern Pennsylvania Transit Authority (SEPTA) and the resulting noise reductions were evaluated initially, at an interim point, and after 112 years of normal operation. Measurements included car interior noise, wayside noise and ground-borne vibration. The final tests and analyses have now been completed. One result is the determination that design of such a testing program must include prior knowledge of the transit vehicle noise characteristics in order to devise appropriate tests for evaluation of the full effectiveness of the noise reduction procedures in reducing wheel/rail noise. Results of the complete testing program are presented.
On measurements to locate sources of aerodynamic and wheel/rail noise generated by high-speed trains
Authors: Bechert D. , King W. F. , Pfizenmaier E. , Grosche F. R. , Stiewitt H. , Martin A.
Published: October 2005

This investigation was carried out to locate noise sources at high-speed trains (up to 250 km/h) with two different microphone systems. For higher frequencies a concave-mirror directional microphone, using seven microphones in the focus plane, was operated. For lower frequencies the acoustic telescope—a microphone array—consisting of 14 microphones was used, which has been developed at University of Cambridge, and which allows to follow the train electronically with the focus of the system. Radiated noise was measured laterally and above the train. It was thereby possible to isolate wheel/rail noise from aerodynamic noise. At higher frequencies even very small single noise sources, as, e.g., aerodynamic noise from the bumpers could be identified. The potential for reducing wheel/rail noise down to the level where aerodynamic noise sources dominate is shown. It is demonstrated that directional microphone systems are valuable tools to distinguish between different simultaneously radiating noise sources. Directional microphones therefore are also an essential aid attenuating noise at its source. [Work supported by the German Bundesministerium für Forschung and Technologie, and the Deutsche Bundesbahn.]
Calibration of acoustic emission transducers
Authors: Hatano Hajime , Mori Eiji
Published: October 2005

This paper reviews the state of the art on the calibration of acoustic emission transducers, which is essential to establish the basis for the standardization of acoustic emission technology. For this purpose, absolute sensitivity should be determined quantitatively in a sound field similar to that of actual acoustic emission waves. Many attempts were made to characterize acoustic emission transducers. However in most cases, only relative response was measured since the magnitude and frequency distribution of the sound source used were not clear. We developed a new calibration method using a reciprocity technique, and absolute sensitivity was obtained with ease and repeatability [H. Hatano and E. Mori, J. Acoust. Soc. Am. 59, 344–349 (1976)]. Besides a longitudinal sound field, a Rayleigh-wave sound field was employed to estimate practical characteristics of transducers in a structure such as a pressure vessel wall. An automatic calibration system was constructed as a primary standard, where a large hammered-steel block was used as an acoustical medium to make precise calibration based on the method. [Work supported in part by Matsunaga Science Foundation.]
Microscopic aspects of fracture and acoustic emission in metals
Authors: Sano K. , Fujimoto K.
Published: October 2005

A review of studies on acoustic emission (AE) during the fracture of metals is presented with an attempt to elucidate relevant microscopic processes. First, experimental results obtained in simplified and well controlled conditions are examined, and then the results in more practical and therefore more complicated circumstances are discussed. To reveal the basic mechanism of AE, observations on the AE accompanied with the crack growth in elastic materials are examined on the basis of the theory of elastic crack propagating at nonuniform velocity. In elastic-plastic materials, the formation of plastic zone ahead of a crack tip and microcracking in the process zone are discussed as the sources of AE. For the unstable fracture in ductile materials, features of AE during slow crack growth are examined from a metallurgical view point and are interpreted in terms of nucleation, growth, and coalescence of voids. It is suggested that the difference in the AE activity among various materials during slow crack growth is attributed to the difference in the mode of void coalescence. Relevant characteristics of AE due to the plastic deformation is also discussed in brief.
On structural-acoustic scale modeling
Authors: SenGupta G. , Hodge C. G.
Published: October 2005

Use of scale models to study the dynamic response of a fuselage structure subjected to acoustic excitation has many advantages. Recently, constructing a ring-stiffened cylinder model of a fuselage for verifying some of the concepts for reducing cabin noise is being considered at Boeing. This has raised questions about the feasibility of using geometrically scaled models for simulating dynamic response of a pressurized fuselage structure. A review of the existing literature shows that it is possible to simulate the dynamic response using geometrically scaled models. The effect of internal pressurization was not considered earlier. It is observed that in order to preserve the scaling laws it is necessary to keep the same pressure differential in the model scale and the full scale structure. Another aspect that was not previously looked into in sufficient details was the effect of scaling down the fuselage stiffeners such as the stringers and frames on their natural frequencies. The importance of stiffener resonances on the low-frequency vibration of the fuselage has been appreciated only recently [G. SenGupta, AIAA Paper 78-504, 19th Structural Dynamics Conference (April 1978)]. It is shown that the relationship among the natural frequencies of the various components existing in a full scale structure can be easily preserved in the model scale structure. It is also shown that the structural-acoustic scaling laws are considerably simplified if a structural Strouhal Number (SSN) is defined in terms of the speed of propagation of the bending waves (VB) in the structure. It is observed that the excitation convection speed in the model scale experiment should be the same as in the full scale, if coincidence excitation of the structure is to be properly simulated.
Acoustic boundary layer and acoustic radiation from a ribbed flat plate
Authors: Pierucci Mauro
Published: October 2005

The acoustic boundary-layer theory (patterned after the viscous boundary-layer theory) is derived by noting that for low frequencies, where the structural wavelength is much less than the fluid acoustic wavelength, there is a region about the vibrating structure which behaves as if the fluid was incompressible. The dimension of this region depends upon the particular conditions of the problem. In a paper presented by the author [J. Acoust. Soc. Am. 62, S32(A) (1977)] the theory behind the acoustic boundary layer was developed and applied to simple unit problems. In this paper the near and the far field of a force driven plate is obtained by the use of the acoustic boundary-layer theory. Two different problems are addressed. In the first instance the structure is assumed to be homogeneous, while in the second problem presented a rib is attached to the flat plate. In both instances the fully coupled fluid structure problem is solved, and comparisons between the exact classical approach and the proposed theory are discussed.
Recursive estimation of autoregressive moving-average parameters in a pole-zero representation of the speech production process
Authors: Morikawa Hiroyoshi , Fujisaki Hiroya
Published: October 2005

A method is presented for estimating the orders as well as the parameter values of an autoregressive moving-average process excited by Gaussian white noise or a train of randomly spaced pulses. This process is adopted as a model for the process of speech production. The estimation is accomplished directly from a signal waveform using recursive formulas and is optimum in the sense that the variance of errors in the estimated waveform is minimized. In comparison with methods based on the short-time autocorrelation function, this method is less vulnerable to fluctuations in the fundamental period of the source. The validity of the proposed method is demonstrated by comparing its results with those obtained on the basis of a fixed-order all-pole formulation, both in terms of the mismatch between the input and the estimated speech spectra and in terms of subjective evaluation of the reconstructed speech. [Work supported by Ministry of Education Grant-in-Aid for Scientific Research No. 239005.]
Geometric sensitivity of frequency spreading due to acoustic scattering from wind driven water surfaces
Authors: Zornig J. G.
Published: October 2005

Several recent studies have focused on the degree to which acoustic scattering from wind driven water surfaces exhibits frequency spreading which is asymmetric in any regular way. Ocean experiments, physical model studies and analytical models have so far not been entirely in agreement on this issue. Therefore a set of physical model experiments has been performed to investigate the sensitivity of frequency spreading asymmetries to variations in geometric parameters. These experiments were conducted using broadband probing signals in the model tank at Yale. Grazing angle, azimuth, projector and receiver beam pattern, acoustic frequency, and surface roughness were varied in a systematic way. The results of this series indicate that frequency spreading is in fact quite sensitive to a number of geometric parameters and that most current analytical models are inadequate to explain the detailed behavior of this phenomenon. [Work supported by NSF and Code 320, Naval Electronic Systems Command.]
Surface reverberation measurements in Daboh Bay and the open ocean
Authors: Lilly J. G. , McConnell S. O.
Published: October 2005

Surface backscatter measurements at low grazing angles have been conducted from stable platforms in deep water in the 10–60-kHz frequency region. Measurements in Dabob Bay utilized a buoy system suspended above the bottom (600 ft) by a 3-point moor. The open ocean measurements were conducted off the southern California coast on the floating instrument platform (FLIP). Both platforms utilized a multibeam acoustic lens as the receiver. Results show the surface backscattering strength to be independent of frequency, rms wave height, and azimuth, but a strong function of wind speed. The power spectra exhibit a strong dependence upon rms wave height and azimuth, but are relatively insensitive to grazing angle and wind speed. A physical model which suggests that the small scale ripple is the primary source of surface reverberation will also be presented. [Work supported by the Naval Sea Systems Command under contract N00024-78-C-6018.]
Coherence of bottom-reflected sound in the Tagus Abyssal Plain
Authors: Berkson J. M. , Dicus R. L. , Anderson R. S.
Published: October 2005

Coherence of bottom-reflected sound in the Tagus Abyssal Plain was determined as a function of bearing at frequencies 50–500 Hz for a fixed grazing angle of 15°. SUS charges were dropped at 244 m depth in a circular pattern of 28 km radius around a receiver at 2500 m depth in water 5100 m deep. The bottom reflected signals were isolated and processed to remove the decorrelating effects of varying bubble pulse periods. Computed was a coherence function ρ(ω,φ) = |Smn(jω)|4/Sm(ω)Sn(ω), where S is a sample estimate of the power spectral density, j is −1, ω is the radian frequency, and m, n are the indices of adjacent shots at an average bearing φ. For a given frequency, the measured coherence function vs bearing exhibits a degree of symmetry in which features occur in pairs 180° apart. This observation suggests a directionally dependent, coherence-degrading effect operating at the bottom, in the water column, or both, and significant over an aperture of 5 km. [Work supported by NORDA Ocean Programs Office.]
The clarinet reed and its relation to the clarinet mouthpiece
Authors: Backus John
Published: October 2005

Clarinet reeds are made from a natural cane, so that such physical properties as elasticity and density vary considerably not only among individual reeds but also between different portions of the same reed. The “lay” of the clarinet mouthpiece, to which the reed is attached, has a curved portion against which the tip of the reed vibrates when the clarinet is sounded. A variety of mouthpieces are available which vary somewhat in the exact shape of the curved portion of the lay; because of the unpredictability of cane reeds, finding a well-behaved reed depends on selecting one which fits the lay properly when vibrating, and is a matter of chance. Synthetic reeds have been developed in this laboratory which are constructed of inorganic materials and hence are reproducible in their characteristics. By mounting such a reed on a mouthpiece, putting it under blowing pressure, and observing its shape in relation to the curvature of the mouthpiece lay, it is possible to determine the best fit of the reed to the lay for a “good” clarinet tone. Observable deviations from this best fit produce characteristic deviations from the “good” tone. [Work supported by the NSF.]
Noise propagation measurement using a signal detection technique
Authors: Ishii Y. , Igarashi J. , Yamada I. , Miki Y.
Published: October 2005

A new technique to measure the ground to ground noise propagation was developed. The test sound of a band limited noise is emitted from a speaker intermittently, a several seconds burst of the noise followed by a pause of the same period. At the receiving spot, the sound intensity is integrated alternatively by two digital counters. One counter integrates the intensity of the test sound plus the background noise at that spot in the period for which the test sound is present. The other integrates the intensity of the background noise in the absent period of test sound. Synchronization of the devices at the source and receiving spots is kept by wireless means such as transceivers. After the completion of a predetermined number of integrations, the difference of the accumulated numbers in the two counters is read, which gives the intensity of the test sound at the receiving spot. Experiments using a 7-W speaker showed that the noise attenuations of the distance of 170 m can be measured with the statistical error less than 0.5 dB.
The excess attenuation of outdoor noise propagating over the ground
Authors: Yamashita Yasuhiro , Matsui Masayuki
Published: October 2005

The field experiments of the noise propagating over the ground were carried out, varying the combination of height of an artificial noise source and a receiving point. We pay attention to the excess attenuation obtained from the noise propagating over the ground. The results obtained are as follows: (1) The excess attenuation of the low frequency obtained from the noise propagating over the soft ground is larger than we expected and also affected by the wind; (2) the excess attenuation obtained is, as a whole, larger in summer than in winter. From the data obtained, the empirical equation predicting the excess attenuation is introduced. [T. F. Embleton, J. E. Piercy, and N. Olson, J. Acoust. Soc. Am. 59, 267–277 (1976)] Furthermore, referring to the data measured by other researchers [P. H. Parkin and W. E. Scholes, J. Sound Vib. 2, 353–374 (1965)], it is shown that the equation is applicable to predict the excess attenuation over the ground.
The sound by a transverse impact of a mass on a plate
Authors: Takahagi T. , Nakai M.
Published: October 2005

The sound generated when a ball strikes a circular plate is investigated both experimentally and theoretically. The purpose of this investigation is to get a fundamental theory for the reduction of impact noise. A ball made of steel or rubber is hung by a string and strikes a circular plate, which is made of steel and attached with screws to a thick steel cylinder, in the same manner as a pendulum. For the theoretical investigation, Timoshenko's stepwise numerical integration procedure will be introduced to solve an equation of transverse impact vibration. We assume that the point sources are distributed all over the plane surface in order to calculate the sound pressure of the impact sound. The experimental results almost agree with theoretical results. The maximum value of the impact sound pressure is proportional to the momentum of the ball. The frequency components of the impact sound depend on the material of a ball and the thickness of a plate. We cannot ignore the influence of the damping coefficient of a plate when calculating the maximum value of impact sound pressure.
AE behavior of various materials
Authors: Nakasa Hiroyasu
Published: October 2005

To apply the AE techniques to the structural integrity monitor in many industrial areas, it is necessary to get a good understanding on the AE behavior of the structural materials and to accumulate basic reference data related to various modes of failure. The AE behavior is strongly affected by both the material inherent nature and the external conditions such as stress, temperature and the surrounding atmosphere. AE event-rate and peak-amplitude-distribution characteristics, which are the best indicators of the AE activities for first arrival signals entered into a selected transducer, are summarized in the process of uniaxial tension and/or compression loading for various industrial materials of steels, nonferrous metals, and nonmetals. The changes of the AE activities are also presented from the sound state to the degraded state followed by neutron irradiation, strain-aging, thermal degradation, corrosion, fatigue, etc.
Properties and physiological application of focused fluid shock waves
Authors: Häusler E. , Hirtt P.
Published: October 2005

Shock waves in solids provoke tensile stresses at free boundaries (Hopkinson effect), at low impedance surroundings or at great angles of incidence. A similar phenomenon can be observed at fluid-fluid interfaces: gas bubbles can be generated if the acoustic impedance jump and the primary pressure amplitude is sufficient for generating negative pressure (pseudocavitation). This will occur especially in the case of focused shock waves. The shock waves are generated in water by spark gap arrays or exploding wires and focused by a torus reflector. At the surface of the water a petroleum layer is arranged. In high speed schlieren- and shadow-optical picture series their propagation can be observed. Quantitative measurements are made with piezoelectric transducers. The results are important for the therapy of kidneystones with shock waves: the human tissue acoustically behaves as a fluid and by the pseudocavitation tissue damages may occur. Other applications and methods to prevent tissue damages are discussed.
Identification of deleted plosives
Authors: Pols Louis C. W. , Schouten M. E. H.
Published: October 2005

When vowel transitions, originating from (C)V or V(C) syllables, are presented to subjects for identification of the deleted consonants, it is generally found that VC transitions are better cues for the identification of final consonants than CV transitions are for initial consonants. However, the lower score for CV transitions could very well be due to an interfering “click sensation” caused by the abrupt spectral onset of these transitions. In the present investigation this abrupt onset was eliminated by replacing the deleted portion of the consonant with a 300-ms burst of noise. This also caused the incomplete (C)Vt or tV(C) syllable to sound more natural; it was as if the syllable emerged from or vanished into the noise. The results show that the addition of noise greatly improves the identification of deleted initial voiceless plosives. The original difference between initial and final plosive transitions disappears almost completely. [Research supported by the Netherlands Organisation for the Advancement of Pure Research (ZWO).]
High performance speaker-independent word recognition
Authors: Doddington George R. , Hydrick Barbara M.
Published: October 2005

Speaker-independent recognition of words spoken in isolation was performed using a very large vocabulary of over 26 000 words taken from the “Brown” data set. (Computational Analysis of Present-Day American English by Kucera and Francis). After discarding 4% of the data judged to be spoken incorrectly, experimental recognition error rate was 2.3% (1.8% substitution and 0.5% rejection), with negligible difference in performance between male and female speakers. Experimental error rate for vocabulary subsets, ordered by frequency of usage, was 1.0% for the first 50 words, 0.8% for the first 120 words, and 1.2% error for the first 1500 words. An analysis of recognition errors and a discussion of ultimate performance limitations will be presented.
Speaker identification: New vectors for SAUSI
Authors: Hollien Harry , Johnson Charles C. , Doherty E. T.
Published: October 2005

A semiautomatic speaker identification system (SAUSI) has been described (Proc. IEEE Conf. ASSP, 768–771 (1977)). This system employs four major vectors: (1) long-term speech spectra, (2) f0 analysis, (3) formant tracking, and (4) temporal analysis. Recently, the f0 analysis and temporal analysis vectors have been replaced by new ones each consisting of an expanded number of parameters. The new f0 vector is based on the mean and s.d. of the frequency distribution plus a parameter array consisting of the numbers of frequencies falling into 15–20 semitone interval “bins.” The temporal vector consists of an array of four 2–34 parameter subvectors as follows: (1) duration of speech rate (DSR), (2) voice/voiceless speech-time ratio (V/VL), (3) time-energy distribution (TED), and (4) vowel/consonant duration ratio (V/C). The nature and analysis techniques of these several vectors will be discussed as will their robustness as speaker identification cues in studies involving speaker and system distortions.
Speech perception by the chinchilla: Learning functions for pairs of synthetic stimuli from various points along a VOT continuum
Authors: Miller J. D. , Henderson B. C. , Sullivan H. T. , Rigden G. K.
Published: October 2005

Previous work indicates that the chinchilla hears an abrupt qualitative change in a particular region along a synthetic VOT continuum in a manner similar to human listeners. To further test this notion naive animals were trained on pairs of stimuli separated by 30 ms from three points along a |ga-ka| VOT continuum. Those animals trained on an intercategorical pair learned rapidly and reached levels of 86%–94% correct. Animals trained on intracategorical pairs learned slowly and reached levels of 52%–79% correct. Next the animals were tested for generalization with stimuli presented with VOTS at the 10-ms intervals from 0–80 ms. Overall, the results indicate there is a strong tendency for the chinchillas to exhibit a “natural boundary” in the short-voicing lag region of the synthetic VOT continuum. The endpoint stimuli, however, seem to be separable from the rest and with prolonged training chinchillas seem to be able to learn to identify in a better than chance, but less than perfect manner, any single stimulus in a set. [Work supported by NS 03856.]
Effects of utterance continuity on phonetic judgements
Authors: Dechovitz D. R. , Rakerd B.
Published: October 2005

The fricative-affricate distinction is signalled by a set of diverse acoustic features. To account for the integration of these features in perception, it is presumed that we perceive the articulatory act from which their coherence is derived. In the present research, our aim is to learn more about conditions which determine whether a particular set of acoustic cues is perceived as the consequence of a fricative or affricate production. To this end, we have examined the significance of short durations of silence for distinguishing word-initial fricative from affricate following precursors which provide various degrees of utterance continuity. Results suggest that continuity of utterance affects the meaning of silence for the fricative-affricate contrast.