bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of various sets of acoustic cues for the perception of prevocalic stop consonants. I. Perception experiment
Authors: Smits Roel , ten Bosch Louis , Collier René
Published: October 2005

The purpose of the study presented in this paper and the accompanying paper [Smits et al., J. Acoust. Soc. Am. 100, 3865–3881 (1996)] is to evaluate whether detailed or gross time-frequency structures are more relevant for the perception of place of articulation of prevocalic stop consonants. To this end, first a perception experiment is carried out with ‘‘burst-spliced’’ stop-vowel utterances, containing the Dutch stops /b,d,p,t/ and /k/. From the utterances burst-only, burstless, and cross-spliced stimuli were created and presented to listeners. The results of the experiment show that the relative importance of burst and transitions for the perception of place of articulation to a great extent depends on place and voicing of the stop consonant and on the vowel context. Velar bursts are generally more effective in cueing place of articulation than other bursts. There is no significant difference in the effectiveness of /p/, /t/, and /k/ transitions, while /b/ transitions are more effective than /d/ transitions. The release burst dominates the perception of place of articulation in front-vowel contexts, while the formant transitions are generally dominant in nonfront vowel contexts. The bursts of unvoiced stops are perceptually more important than the bursts of voiced stops.
Loudness level survey of the Newberry Memorial organ, Yale University
Authors: Harrison J. M. , Thompson-Allen N.
Published: October 2005

The Newberry Memorial organ, Yale University, is an example of a large Skinner organ built in the late 1920s. The diapason choruses and reeds of this organ were designed by G. D. Harrison in 1928, and represent an early example of his work. The purpose of the present work was to provide objective measurements of loudness levels across the compass of the major divisions of the organ at a prime listening location. The C-weighted sound-pressure level of all the C’s of each stop was measured. The SPL readings were transformed, with corrections, to loudness levels using the Robinson and Dadson [Br. J. Appl. Phys. 7, 166–181 (1956)] contours. The pattern of loudness levels across the compass of the organ was the same for all unison stops. The levels peaked in the middle octave and fell steadily either side 10 to 40 phons. Sixteen- and 32-ft stops followed the pattern of decline in loudness levels set by the unison stops. Higher frequency stops (4 ft, 2 ft, and mutations) also continued the downward trend of levels set by the upper end of the unison stops. The data of the present survey agreed with an extensive qualitative description of the dynamic level of the organ at its completion in 1929.
Ultrasonic determination of the anisotropy of Young’s modulus of fixed tendon and fixed myocardium
Authors: Hoffmeister Brent K. , Handley Scott M. , Wickline Samuel A. , Miller James G.
Published: October 2005

The linear elastic properties of a soft tissue exhibiting a unidirectional arrangement of reinforcing fibers may be described in terms of the five independent elastic stiffness coefficients c11, c13, c33, c44, and c66. In previous studies, ultrasonic measurements of these coefficients for formalin fixed specimens of bovine Achilles tendon and normal human myocardium were reported. In the present study these results are used to analyze the anisotropy of Young’s modulus of these tissues. For formalin fixed tendon a value of 1.37 GPa is obtained for Young’s modulus along the fiber axis of the tissue, and a value of 0.0706 GPa is obtained perpendicular to the fibers. For formalin fixed myocardium, values of 0.101 and 0.0311 GPa parallel and perpendicular to the fibers, respectively, are obtained. Based on the results for the angular dependence of Young’s modulus from unidirectional specimens of myocardium, a model is introduced to estimate these features for the more complicated fiber architecture of the left ventricular wall.
Application of dynamic programming matching to classification of budgerigar contact calls
Authors: Ito Ken , Mori Koich , Iwasaki Shin-ichi
Published: October 2005

Dynamic programming (DP) matching was applied to classification of budgerigar contact calls. Our DP-matching algorithm calculates distances between two calls with time warping. It was compared to other methods including linear matching methods and methods using cross correlation, and was evaluated in classifying calls into natural groups. The DP-matching method with two peak frequencies with some tolerance in frequency comparison (DP2peak) and the cross-correlation method using two peak frequency tracks with frequency shift (Corr2shift) were equally effective in classifying obviously different calls. DP2peak proved more effective than any other methods tested in classifying minutely different cagemate calls. Use of two peak frequencies, time warping in matching calls, and tolerance of frequency shift were found to be the three most important factors in mimicking the bird’s own classification of natural calls, whereas intensity differences of peak frequencies did not play an important role. The possibility of similar processes of call discrimination in the bird’s brain, such as simultaneous perception of two frequencies and time warping in comparing calls, was discussed in relation to these results.
Pitch, periodicity, and auditory organization
Authors: Hartmann William M.
Published: October 2005

The perception of pitch forms the basis of musical melody and harmony. It is also among the most precise of all our human senses, and with imagination, this precision can be used experimentally to investigate the functioning of the auditory system. This tutorial presents auditory demonstrations from the zoo of pitch effects: pitch shifts, noise pitch, virtual pitch, dichotic pitch, and the pitches of things that are not there at all. It introduces models of auditory processing, derived from contemporary psychoacoustics and auditory physiology, and tests these models against the experimental effects. It concludes by describing the critical role played by pitch in the important human ability to disentangle overlapping sources of sound.
On the relation between the wavefront speed and the group velocity concept
Authors: Leander Johan L.
Published: October 2005

The relation between the wavefront speed and the group velocity concept is studied in this work. The relationship between the more well-known velocity concept named as the phase velocity and the speed of propagation of a front of an acoustic pulse is discussed. This is of interest since it concerns transient wave propagation and is, in general, not well known. The form and properties of a pulse can be obtained by means of a Fourier integral and estimates based on quantities derived for monochromatic waves, such as the phase velocity, can be severely misleading and confusing. The wavefront velocity is defined as the high-frequency limit of the phase velocity. This quantity can be far less than the value of the phase velocity for finite frequencies which for example is the case for bubbly fluids. Then the group velocity concept is discussed, which was introduced in order to characterize the propagation of water waves of essentially the same wavelength. However, more confusion occurs in that it is sometimes believed that a wavefront is propagating with the group velocity (a limit process not mentioned) since it can be related to the propagation of energy. This interpretation of energy propagation is based on sinusoidal waves and involves time as well as space averages and is not applicable for pulses. However, by means of the expression for the group velocity given by Stokes it is shown that the speed of a wavefront can be found from the group velocity at a limiting high frequency. This result can be understood geometrically from the definition of the group velocity given by Lamb which is conservation of wavelength. A wavefront is a discontinuity and limiting short wavelengths will be found there.
Reciprocity theorems for two-way and one-way wave vectors: A comparison
Authors: Wapenaar C. P. A.
Published: October 2005

For acoustic applications in which there is a ‘‘preferred direction of propagation’’ (the axial direction) it is useful to arrange the two-way and one-way wave equations into the same matrix-vector formalism. In this formalism, axial variations of the wave vector are expressed in terms of lateral variations of the same wave vector. The two-way wave vector contains the field quantities pressure and velocity (axial component only), whereas the one-way wave vector contains waves propagating in the positive and negative axial direction. By exploiting the equivalent form of the two-way and one-way matrix-vector equations, it appears to be possible to derive two-way and one-way reciprocity theorems that have an equivalent form but a different interpretation. The main differences appear in the boundary integrals for unbounded media, in the contrast terms, and (for the correlation-type theorems) in the handling of evanescent waves.
Numerical determination of scattered field amplitudes for rough surfaces
Authors: McNamara Richard C. , DeSanto John A.
Published: October 2005

In theory, when an incident plane wave strikes a perfectly reflecting periodic surface, the resulting scattered field is comprised of a discrete spectrum of plane waves. Upon applying Dirichlet boundary conditions to the surface, one can construct what is referred to as a spectral-coordinate (SC) formalism for the scattered amplitudes. A Fredholm integral equation of the first kind is involved, and the integration is performed over a single surface period. Since the Rayleigh approximation is not utilized in the construction of this formalism, one may use this method to determine the exact scattered field above the highest surface excursion. The problem will be approached numerically by directly discretizing the mixed SC representation, then solving the system using a pseudoinverse SVD technique. It is very important to note that the scattered amplitudes are obtained without constraining the value of normalized energy. This particular approach is unique. It differs from others in which the discretizations are implemented entirely in coordinate space or entirely in spectral (i.e. Bragg) space. It is thus an additional computational tool designed for cases when a mixed representation is appropriate. Although this numerical scheme has been developed for arbitrary periodic surfaces, the results presented in this paper are restricted to sinusoidal surfaces. Particularly interesting features of this approach are the high level of accuracy attained for near-grazing incident fields and the maintenance of stability even for badly conditioned systems of equations.
Elastic wave and excitation mechanism of surface waves in multilayered media
Authors: Zhang Bixing , Yu M. , Lan C. Q. , Xiong Wei
Published: October 2005

The elastic wave field and the excitation mechanism of the surface waves in multilayered elastic solid media are studied in this paper. On the basis of Abo-zena [Geophys. J. R. Astron. Soc. 58, 91–105 (1979)] and Menke [Geophys. J. R. Astron. Soc. 59, 315–323 (1979)], the elastic wave field is further investigated in the B, P, C coordinate system. The so-called new type of propagator matrix introduced by Menke to avoid loss of the precision problem is improved. It presented an important result and some new properties. The dispersion characteristics and excitation mechanisms of the surface waves (Rayleigh and Love waves) are also investigated via numerical simulation. The excitation intensities of the surface waves strongly depend on the frequency range of the source. The source frequency should be controlled in a proper range to effectively excite the surface waves. Two quantities, β1 (the ratio of B to P components of displacement) and β2 (the ratio of B to P components of stress), are defined for the Rayleigh wave. It is found that β1 and β2 are sensitive to the material property of the medium and the layered geometry, and they are two important physical quantities for exploring the structures of the interfaces and the velocity distributions of layers under the free surface. The relative error in estimating the thickness of each medium by β1 and β2 is less than 10%. The effects of the thickness of each layer of media and other factors on the dispersion characteristics of Rayleigh and Love waves and the values of β1 and β2 are also analyzed.
Mode coupling by internal waves for multimegameter acoustic propagation in the ocean
Authors: Colosi John A. , Flatté Stanley M.
Published: October 2005

We have performed broadband parabolic-equation simulations with and without sound-speed fluctuations induced by internal waves. The simulations have a center frequency of 75 Hz, a bandwidth of 30 Hz, and propagation range R of 1000, 2000, and 3000 km. In these cases it is found that long-range acoustic propagation through internal waves is strongly nonadiabatic. In terms of modal travel times, low modes have a negative bias (they have a higher effective group speed than without internal waves) because they couple into higher, faster modes, while the higher modes show a positive bias, indicating preferential coupling into lower, slower modes. The lowest modes show the least travel-time spread and bias, and these quantities increase rapidly with increasing mode number. Empirically and approximately it is found that bias grows like R2 and spread grows like R3/2. This average slowing down and spreading of the higher modes causes a depth broadening of the reception finale. The modeled modal power distributions over frequency at multimegameter ranges are markedly different from the initial distributions at the source. Power is distributed roughly equally across the 30-Hz frequency band for each mode, with 5.6-dB scintillations consistent with an exponential probability distribution function for intensity. In spite of the dramatic spread and bias in the higher modes, it is found that a synthesis of these modes results in coherent wavefronts, whose characteristic timing fluctuations at the 3000-km range are two orders of magnitude less than those of the corresponding modes. The modal spreads found in these simulations imply limits to the precision with which modal travel times can be measured using standard techniques. A nonstandard approach, using the geometric mean of independent realizations after transformation to the frequency domain, effectively averages the phase fluctuations and eliminates much of the spread. The strong modal coupling nonetheless suggests that nonadiabatic modal inversions will be necessary to do modal tomography at multimegameter ranges.
Frequency tuning and acoustic enhancement of electrically evoked otoacoustic emissions in the guinea pig cochlea
Authors: Kirk Desmond L. , Yates Graeme K.
Published: October 2005

Electrically evoked otoacoustic emissions (EEOAEs) were generated by ac stimulation in scala media of turns 1, 2, and 3 in the guinea pig cochlea. In each turn EEOAEs were recorded at frequencies up to and slightly above the estimated characteristic frequency (CF) of the stimulation site. Acoustic enhancement of EEOAEs was present at all emission frequencies in turns 2 and 3 but could be demonstrated in turn 1 only at emission frequencies that fell within a notch in the EEOAE tuning function. There was no evidence, in any turn, of a transition from enhancement to suppression as the emission frequency approached the CF of the stimulation site. The results were not consistent with the hypothesis [D. C. Mountain and A. E. Hubbard, Hear. Res. 42, 195–202 (1989)] that acoustic enhancement results from a reduction in the effectiveness of forward transduction in a negative feedback loop.
Direct observation of microbubble oscillations
Authors: Tian Yuren , Ketterling Jeffrey A. , Apfel Robert E.
Published: October 2005

A direct imaging system is introduced to study the oscillations of microbubbles acoustically levitated in water. The bubble is illuminated with a light emitting diode (LED) which is strobed at a frequency different from the driving sound field. This technique slows the moving image of the bubble, allowing one to observe the shape of a bubble oscillating between 5 to 100 μm in diameter. The bubble shapes are recorded on video tape and then analyzed by an automatic image analysis system which gives the variations of bubble diameter versus time. Experiments were performed with and without the bubbles sonoluminescing. Asymmetric shapes of the bubbles were observed in some cases.
Perception of asynchronous and conflicting visual and auditory speech
Authors: Massaro Dominic W. , Cohen Michael M. , Smeele Paula M. T.
Published: October 2005

Previous research has shown that perceivers naturally integrate auditory and visual information in face-to-face speech perception. Two experiments were carried out to study whether integration would be disrupted by differences in the stimulus onset asynchrony (SOA), the temporal arrival of the two sources of information. Synthetic visible and natural and synthetic auditory syllables /ba/, /va/, /ð/, and /da/ were used in an expanded factorial design to present all possible combinations of the auditory and visual syllables, as well as the unimodal syllables. The fuzzy logical model of perception (FLMP), which accurately describes integration, was used to measure the degree to which integration of audible and visible speech occurred. These findings provide information about the temporal window of integration and its apparent dependence on the range of speech events in the test.
On acoustic attenuation by swimbladder fish
Authors: Ye Zhen
Published: October 2005

This letter presents a theoretical study of sound attenuation by swimbladder fish. Since the sound attenuation is related to the sound extinction cross section, the focus of the letter is on theoretical calculation of the extinction cross section of swimbladder fish. A forward scattering theorem is used for the purpose. Based on simple scattering models for swimbladder fish, the frequency dependence of the extinction cross section is obtained. The result shows that while the air-filled swimbladder dominates the forward scattering of sound at low frequencies, the fish body may dominate the forward scattering in the high-frequency range. Without fitting parameters, the theoretical results compare favorably with some existing experimental data.
Speech intelligibility prediction in hearing-impaired listeners based on a psychoacoustically motivated perception model
Authors: Holube Inga , Kollmeier Birger
Published: October 2005

Sensorineural hearing-impaired listeners suffer severely from deterioration in the processing and internal representation of acoustic signals. In order to understand this deterioration in detail, a numerical perception model was developed which is based on current functional models of the signal processing in the auditory system. To test this model, the individual’s speech intelligibility in quiet and in noise was predicted. The primary input parameter of the model is the precisely measured audiogram of each listener. In a refined version of the model, additional input parameters are derived from predicting the individual’s temporal forward masking and notched-noise measurements with the same model assumptions. The predictions of the perception model were compared with those of the articulation index (AI) and the speech transmission index (STI). The accuracy of prediction with the perception model is in the same range as with the AI and the STI. The model does not require a calibration function and has the advantage of a greater flexibility in including different processing deficits associated with hearing impairment. However, it requires more time for computation. For the hearing-impaired listeners examined so far the individually measured psychoacoustical parameters have only a secondary effect on the prediction as compared to the audiogram. Nevertheless, the underlying model is a first step toward a quantitative understanding of speech intelligibility and helps to distinguish between the influence of the ‘‘attenuation’’ and the ‘‘distortion’’ component of the hearing loss.
Sensory consonance and the perceptual similarity of complex-tone harmonic intervals: Tests of adult and infant listeners
Authors: Schellenberg E. Glenn , Trainor Laurel J.
Published: October 2005

Two experiments examined the influence of sensory consonance on the perceptual similarity of simultaneous pairs of complex tones (harmonic intervals). In experiment 1, adults heard a sequence of five consonant intervals (each a perfect fifth, or 7 semitones) and judged whether a subsequently presented test interval was a member of the sequence. Discrimination performance was better when the test interval was dissonant (tritone, 6 semitones) rather than consonant (perfect fourth, 5 semitones), despite the fact that the change in interval width was twice as great for the consonant than for the dissonant comparison. In experiment 2, 7-month-old infants were tested with an operant headturn procedure in a similar design and exhibited an identical pattern of responding. Hence, for both age groups, consonance was more important than interval width in determining the perceived similarity of harmonic intervals.
The effect of segment duration on the perceptual integration of nasals for adult and child speech
Authors: Ohde Ralph N. , Ochs Marleen T.
Published: October 2005

It has been hypothesized that the acoustic properties within a temporal domain of 10 to 30 ms of boundaries between speech sounds contain significant information on the phonetic features of segments, and that these cues are perceptually integrated by the auditory system [Stevens, Phonetic Linguisitics: Essays in Honor of Peter Ladefoged (Academic, London, 1985)]. The purpose of the current research was to examine the effects of stimulus duration adjacent to speech sound boundaries on the perceptual integration of place of articulation of nasals before and after disruption of the abrupt changes in spectra between the murmur and transition. In experiment I, three children, aged 3, 5, and 7 years, and an adult female and male produced consonant–vowel (CV) syllables consisting of [m] and [n] in four vowel contexts, [i æ u 𝕒]. Approximately 25-ms segments of the murmur and vowel transition adjacent to the speech sound boundary were digitally removed from these productions. Intervals of silence ranging from 0 to 2000 ms, which can potentially perturb integration processes, were inserted between these segments. The stimuli were then presented to adult listeners for the identification of the nasal. The main findings revealed a consistent decline in identification with gap durations up to 150 ms across speakers and vowel context. However, the adult labial feature was resistant to perceptual change as a function of gap duration. This result appeared to relate to formant transition duration, and not to response bias. In experiment II, stimuli with durations shorter than those in experiment I were further analyzed for adult speakers. The main finding was a quantification of the acoustic segment duration needed for perceptual integration of the murmur and vowel transition. Across both experiments, the results reveal a decline in the identification of both alveolar and labial nasals within a time interval mediated by short-term auditory memory, and that the duration of the acoustic segment needed for perceptual integration is longer for [n] than [m].
An HMM-based speech recognizer using overlapping articulatory features
Authors: Erler Kevin , Freeman George H.
Published: October 2005

State-of-the-art speech recognition is accomplished by using stochastic models (hidden Markov models) to represent small, nonoverlapping segments of speech (phonemes or allophones). In these traditional HMM speech recognizers, the control strategy does not draw extensively on the underlying structure of speech, but rather models speech as a set of disjoint ‘‘segmental’’ units. Such a strategy does not easily accommodate the influence that phonemes have on neighboring phonemes, nor does it attach any meaning to the internal states of the model. In this work, an alternative HMM control strategy is presented which draws on the idea that the production of speech is a process governed by the mechanical motion of a set of relatively slow moving ‘‘articulators.’’ The articulatory feature model is defined as an HMM in which each internal state of the model represents one possible configuration of the (quantized) articulatory system. Rather than modeling disjoint segments, this model represents the acoustic patterns associated with the various articulatory configurations of the speech production system. Instead of a set of disjoint models, this scheme represents the entire vocabulary with a single, large HMM. The internal model states now have meaning due to their correlation with the physical state of the production system. This allows the incorporation of linguistic and physiological knowledge to improve performance. System philosophy, implementation, and results are discussed.
Onboard acoustic recording from diving northern elephant seals
Authors: Fletcher Stacia , Le Boeuf Burney J. , Costa Daniel P. , Tyack Peter L. , Blackwell Susanna B.
Published: October 2005

This study was the first phase in a long-term investigation of the importance of low-frequency sound in the aquatic life of northern elephant seals, Mirounga angustirostris. By attaching acoustic recording packages to the backs of six translocated juveniles, the aim was to determine the predominant frequencies and sound levels impinging on them, and whether they actively vocalize underwater on their return to their rookery at Año Nuevo, California, from deep water in Monterey Bay. All packages contained a Sony digital audio tape recorder encased in an aluminum housing with an external hydrophone. Flow noise was minimized by potting the hydrophone in resin to the housing and orienting it posteriorly. The diving pattern of four seals was recorded with a separate time–depth recorder or a time–depth–velocity recorder. Good acoustic records were obtained from three seals. Flow noise was positively correlated with swim speed, but not so high as to mask most low-frequency sounds in the environment. Dominant frequencies of noise impinging on the seals were in the range 20–200 Hz. Transient signals recorded from the seals included snapping shrimp, cetacean vocalizations, boat noise, small explosive charges, and seal swim strokes, but no seal vocalizations were detected. During quiet intervals at the surface between dives, the acoustic record was dominated by respiration and signals that appeared to be heartbeats. This study demonstrates the feasibility of recording sounds from instruments attached to free-ranging seals, and in doing so, studying their behavioral and physiological response to fluctuations in ambient sounds.
Transfer matrix of a uniform duct with an axial mean temperature gradient
Authors: Sujith R. I.
Published: October 2005

The purpose of this Letter is to present expressions for the four-pole parameters of a duct with an axial mean temperature gradient. Algebraic expressions are derived for the case of linear and exponential temperature profiles. These expressions are valid for arbitrarily large temperature gradients and they differ from those in the earlier literature that are valid only for small temperature gradients. The analysis neglects the effects of mean flow and is therefore valid only for small mean Mach numbers.
Ocean current and vorticity measurements using long-range reciprocal acoustic transmissions
Authors: Worcester Peter F.
Published: October 2005

Measurements of the sum and difference of the travel times of acoustic pulses propagating in opposite directions provide powerful tomographic tools. Travel-time signals due to sound-speed perturbations cancel in the difference travel time, leaving only the much smaller signals due to currents. Reciprocal acoustic transmissions are particularly well suited to measuring large-scale barotropic flow and areal-average relative vorticity, both of which are of great oceanographic importance, but difficult to measure using other techniques. The use of reciprocal transmissions to measure ocean currents and vorticity has been tested in a series of experiments at steadily increasing ranges, from 25 to 1275 km. Acoustically derived currents and vorticity have been found to be consistent with independent measurements in all cases. The barotropic tides have provided the best test signals, because they are both well known and of large scale. Point measurements provided by current meters provide less stringent tests. The high-frequency travel-time fluctuations due to internal-wave-induced sound-speed perturbations have been found to largely cancel in the differential times, demonstrating that the ray paths of oppositely traveling signals are nearly reciprocal out to 1-Mm ranges, as is implicitly assumed when differential travel times are used to deduce ocean currents.
Measuring currents with acoustic propagation
Authors: Farmer David M.
Published: October 2005

Water currents refract and otherwise modify acoustic signals providing a basis for their remote detection. In recent years this concept has been explored with high-frequency propagation in the coastal environment, but the concepts have a broader application to ocean measurement. The component of flow resolved along the acoustic path may be detected through changes in effective sound speed. Phase coherent reciprocal transmission allows separation of current-induced effects from scalar contributions due to temperature or salinity, leading to measurements of great accuracy and precision. For turbulent flows this approach has been extended into the inertial subrange, permitting measurement of path averaged dissipation. In contrast, coherence of the refractive variability permits measurement of the component of flow orthogonal to the acoustic path through detection of scintillation drift with an array. Additionally, current advection of the pulse may be detected as a change in horizontal arrival angle. Resolution of both current speed and refractive variability as a function of path position can be achieved by combining multielement source and receiver arrays in a spatial aperture filter. These concepts are now being applied in the Bosphorus to the measurement of exchange with the Black Sea using a two-level reciprocal scintillation array.
Validation of launch vehicle sonic boom predictions
Authors: Downing J. Micah , Plotkin Kenneth
Published: October 2005

Concern has been raised about the sonic boom levels generated by launch vehicle operations. To address this concern the USAF recently monitored the sonic boom generated by the launch of a Titan IV rocket and the reaction of the local wildlife. The sonic boom generated by this launch intersected the Channel Islands off the coast of Southern California. The sonic booms were recorded by the USAF Boom Event Analyzer Recorder and by DATs with low-frequency microphones on San Miguel, Santa Rosa, and Santa Cruz islands. Before the launch, predictions were made to assess the sonic boom impact on the islands. The prediction model used in this comparison was PCBoom3, a single-event sonic boom model developed by the USAF. This model has been updated to model sonic booms generated by launch vehicles and includes the effect of the rocket plume on the generation of the sonic boom. The measured sonic boom signatures are compared to predictions.
Effects of perforated pipe on the higher-order modes in an elliptical chamber
Authors: Ikeda Tatsuyu , Nishimura Tsuyoshi , Usagawa Tsuyoshi , Ebata Masanao
Published: October 2005

The role of the perforated pipe in a simple elliptical expansion chamber, especially its ability to improve noise reduction by decreasing the level of resonance caused by traverse waves, is presented. The characteristics of the perforated pipe have been studied by means of impedance which depends on the shape and porosity of a pipe. The following phenomena regarding sound-pressure distribution when the perforated pipe is located at the center of a simple elliptical expansion chamber have been observed. (1) The resonance frequencies of higher-order modes shifted to the lower frequency ranges in comparison with those when a pipe was not attached, and (2) the resonance frequencies inside a perforated pipe are similar to the ones outside; however, the resonance level inside is higher than the one outside. In addition, an arrangement of the output pipe is also studied based on the distribution of higher-order modes in a chamber. The experimental results which tend to prove the effectiveness of the perforated pipe are concretized by a mathematical formula in the paper.
Comparative measurement of second-harmonic generation in various materials
Authors: Hou Xiaoli , Darvennes Corinne
Published: October 2005

Second-harmonic generation was measured in several man-made materials for possible application of nonlinear properties to nondestructive testing. Samples included several thicknesses of two types of polymer matrix composites, three types of concretes, and plywood. Steel and aluminum specimens were used as references and one of the composite samples was evaluated before and after fatigue cycles. A monochromatic ultrasonic signal was sent into each sample via a contact transducer placed on its top surface. The growth of the second harmonic was recorded, with a second transducer placed on the bottom face, as the amplitude of the input signal was gradually increased and for several values of the input frequency. Nonlinearity parameters could not be measured, due to the limitations of our equipment. Nonetheless, some interesting observations were made: (1) the two composites were much more nonlinear than the metals; (2) the concretes and the wood were extremely absorptive and an output signal was observed only at the lowest input frequency; and (3) fatigue cycles significantly increased the second harmonic, even though no damage was observed by C-scanning. [Work supported by NSF, TTU Manufacturing Center, and the FRG Program.]
Modeling nonlinearity and slow dynamics for rock in resonance experiments
Authors: Van Den Abeele Koen E. A. , Guyer Robert A.
Published: October 2005

The presence of compliant features in rock causes nonlinear distortion of sound waves propagating through a sample, even at microstrain levels. When performing resonance experiments, one observes nonlinear behavior in different ways: resonant frequency shifts as function of drive amplitude, nonlinear dissipation including hysteresis, asymmetry of the resonance curves, and rich harmonic spectra. Recently, a new interesting feature has been added to these nonlinearity observations: the existence of a slow dynamics conditioning and recovering characteristic. Experimental evidence will be shown in a companion ASA contribution by TenCate et al. The focus is on the mathematical modeling of all of the nonlinear resonance observations, including the slow dynamics characteristics. The model uses a finite-difference time-domain solution of the one-dimensional wave equation with appropriate boundary conditions, and calculates waveforms along the sample. The key part of the model is the description of a modulus which depends on higher-order elastic constants, hysteresis strength, and its own weighted response over previous times. By integrating the history of the modulus using an exponential weighting function, interesting conditioning and recovering effects can be simulated which agree well with the nonlinear and slow time constant observations in rock. [Work supported by DOE/OBES/UCal.]
Theory and feasibility of breather solitons in sandstone
Authors: Bernard Miguel , Denardo Bruce
Published: October 2005

A theoretical model and an experimental feasibility study of nonlinear Schrödinger breather solitons in a sandstone waveguide are presented. These solitons are acoustic waves that are theoretically characterized by a standing wave motion in the transverse direction, an exponential self-localization along the waveguide, and a speed of propagation that can have any value that is small compared to the speed of sound. The sole requirement in the model is that transverse standing waves soften (the resonance frequency decreases as the amplitude is increased). The softening of a Berea sandstone sample and the resonance frequency quality factors have been measured in the range 500 Hz–15 kHz. With the use of a composite transducer designed to optimize the drive amplitudes, frequency shifts of 7% have been measured. Comparison of this shift with that due to nonuniformities and estimation of the soliton length and decay distance reveal that the observation of the solitons is feasible in Berea sandstone. This is a first step toward the observation of nonlinear Schrödinger acoustic breather solitons in a sandstone core.
Relationships between word knowledge and visual speech perception. II. Subjective ratings of word familiarity
Authors: Waldstein Robin S. , Auer Edward T. , Tucker Paula E. , Bernstein Lynne E.
Published: October 2005

Word familiarity is an important factor in word recognition and lexical access for hearing individuals. Subjective word familiarity ratings are hypothesized to reflect experience with words irrespective of the modality (i.e., spoken or written) through which exposure has taken place, and to provide an estimate of the size of the mental lexicon. To investigate how word familiarity is related to lipreading proficiency, 450 printed words were presented for rating on a seven-point scale to 50 deaf and 50 hearing participants. Preliminary results revealed that the deaf participants produced lower mean familiarity ratings than did the hearing participants, for high-, medium-, and low-familiarity words (hearing means= 6.7, 4.8, 3.0; deaf means= 6.0, 3.8, 2.6). Among the deaf participants, correlations between established familiarity ratings and individuals’ ratings were reliably higher for excellent than for good lipreaders, a possible indication that perceptual experience influences the structure of the lexicon. At the same time, the performance of the excellent lipreaders provides support for the hypothesis that lexical organization does not depend on the perceptual input modality (i.e., vision versus hearing). [Work supported by NIH Grant No. DC00695.]
Face identification using visual speech information
Authors: Yakel Deborah A. , Rosenblum Lawrence D.
Published: October 2005

Traditionally, the recovery of linguistic message and speaker identity is thought to involve distinct operations and information. However, recent observations with auditory speech show a contingency of speech perception on speaker identification/familiarity [e.g., Nygaard etal ., Psychol. Sci. 5, 42–46 (1994)]. Remez and his colleagues [Remez etal ., J. Exp. Psychol. (in press)] have provided evidence that these contingencies could be based on the use of common phonetic information for both operations. In order to examine whether common information might also be useful for face and visual speech recovery, point-like visual speech stimuli were implemented which provide phonetic information without containing facial features [L. D. Rosenblum and H. M. Saldaña, J. Exp. Psychol.: Human Percept. Perform. 22, 318–331 (1996)]. A 2AFC procedure was used to determine if observers could match speaking point-light faces to the same fully illuminated speaking face. Results revealed that dynamic point-light displays afforded high face matching accuracy which was significantly greater than accuracy with frozen point-light displays. These results suggest that dynamic speech information can be used for both visual speech and face recognition.
The effect of utterance duration on visual-speech intelligibility scores
Authors: Gagne Jean-Pierre , Boutin Lina
Published: October 2005

The effect of duration on the visual-speech intelligibility of talkers was investigated. The stimulus set consisted of 25 sentences. Each sentence had the same grammatical structure and contained three critical elements (subject, verb, object). Seven talkers were videotaped while they spoke a list of sentences twice using conversational and clear speech. For each talker, the mean duration of the conversational and clear sentences were measured. The recordings were digitized and dubbed under four conditions: (1) normal conversational; (2) conversational speech decelerated to a speed equivalent to the duration of the talker’s average utterances of clear speech; (3) natural clear speech; (4) clear speech accelerated to a speed equivalent to the talker’s average conversational speech. The test sentences (25 sentences × 2 iterations × 4 durations × 7 talkers) were randomized and shown (without sound) to a group of 18 subjects. The responses obtained during the perceptual task were used to determine each talker’s speech intelligibility for the four experimental conditions. The results revealed a significant effect for sentence duration and talker, as well as a significant sentence-duration x talker interaction. The effects of sentence duration on visual-speech intelligibility will be discussed. [Work supported by NSERC.]
Synthesizing audiovisual speech from physiological signals
Authors: Vatikiotis-Bateson Eric , Yehia Hani
Published: October 2005

Previous examination of perceiver eye movement behavior during audiovisual speech tasks has shown that linguistically relevant visual information is distributed over large regions of the face [Vatikiotis-Bateson et al., ICSLP-94 (1994)]. Furthermore, the simultaneous production of facial and vocal tract deformations suggests a single source of control for acoustic and visual components of speech production. To further examine this possibility, orofacial motion during speech has been correlated with perioral muscle activity, the time-synchronous behavior of vocal tract articulators, and elements of the speech acoustics (e.g., rms amplitude) using both linear and nonlinear modeling techniques. Not surprisingly, since small motions require small forces, linear techniques such as minimum mean square error and second order autoregression provide reasonably good estimates of the inherently nonlinear mapping between muscle EMG and orofacial kinematics. This paper assesses the relative merits of such linear models versus nonlinear, neural network estimations of the orofacial dynamics.
Lexical access in French: Recognizing ‘‘identical’’ phrases
Authors: Bannert Robert , Nicolas Pascale , Stridfeldt Monika
Published: October 2005

Information on word recognition and lexical access has been dominated by research on English. In French, with its different prosodic coding, showing the phonological processes of liaison, enchaînement, and e-deletion, represents an opportunity to widen the understanding of speech recognition. A listening test was carried out containing 20 utterances and ten distractors ranging from one to six syllables and forming seven pairs and two triplets of supposedly ‘‘identical’’ linguistic phrases. A representative sample of each type produced by a male and a female French speaker was presented five times in random order to 18 native listeners of French (including the two speakers) and nine Swedish learners of French as a foreign language. No group identified any of the original utterances correctly, and only two pairs of stimuli were identified at random. Taking into account the frequencies of the stimuli, it appears that most stimuli contain some acoustic information that guides recognition. An acoustic analysis of these utterances showed prosodic and, what might be considered unexpected, according to the literature, segmental differences in spectrum amplitude and F0. [Work supported by the Swedish Council for Research in the Humanities and Social Sciences.]
Frequency effects in malpropisms
Authors: Raymond William , Bell Alan
Published: October 2005

Malapropisms are lexical substitution errors resulting from a failure at the stage of accessing the phonological form corresponding to a lemma—a semantically and structurally specified lexical entry [Fay and Cutler (1977); Garrett (1980)]. An example is tentative fortenable . Since they occur naturally in utterance contexts, malapropisms are an important source of information about this stage of lexical access. A study of over 300 malapropisms confirmed prior findings that errors resemble targets closely in phonological form and in syntactic category. In addition, it was found that errors resemble targets in derivational morphology (independently of phonological similarity), and that there is a strong correlation (r2=0.34) of the text frequencies of the error and target words. The partial correlations of frequency with word length, syntactic category, and segmental similarity only account for one-half of this correlation (residual r2 about 0.17). Models which treat frequency effects as biases on the decision processes of selecting word forms [Luce et al. (1990)] or as form activation thresholds [Jescheniak et al. (1994)] cannot account for such a correlation directly. The results thus appear to support some degree of organization of the lexicon according to frequency, as suggested, e.g., by Forster (1976).
The role of time during lexical access
Authors: Samuel Arthur G.
Published: October 2005

Speech naturally occurs over time—words unfold from ‘‘left-to-right.’’ This structure inherently confounds two logically distinct factors: the amount of phonetic information presented, and the amount of time the perceptual process has been working. For example, in the word ‘‘acoustical,’’ both the elapsed processing time and the number of processed phonemes (or syllables) would be greater for the second /k/ (‘‘c’’) than for the first one. The current study attempts to unconfound these two factors by using speech compression and expansion techniques, coupled with phonemic restoration methodology. The strength of phonemic restoration can be used as an index of the strength of lexical activation. For example, restoration is stronger for word-final phonemes than for phonemes in earlier word positions, due to the higher lexical activation later in words. The current study tests phonemic restoration when available processing time is manipulated via speech compression/expansion. An interesting additional variable that appears to interact with time is the active lexical cohort size: Additional processing time seems to be more useful when the cohort has been narrowed to a small set. The results support and constrain activation models of lexical access. [Work supported by NIMH.]
Spoken word recognition in older adults: Activation and decision
Authors: Charles-Luce Jan , Luce Paul A.
Published: October 2005

Spoken word recognition may be characterized by two successive stages: (1) activation of multiple form-based representations in memory and (2) frequency-biased perceptual decision. Recent research has suggested that older adults show deficits in controlled processing in perceptual and memory tasks, suggesting that while activation mechanisms subserving spoken word recognition may remain relatively intact over time, perceptual decision processes degrade. In order to investigate the possible loci of older adults’ recognition difficulties, perception of specially selected words that orthogonally varied on three dimensions was examined: word frequency, neighborhood density, and neighborhood frequency. Effects of neighborhood density are typically associated with activation mechanisms, whereas neighborhood frequency is associated with perceptual decision. The implications of these results for theories of aging and spoken word recognition will be discussed. [Work supported by grants from NIDCD.]