bluuebunny/crossref_metadata_2025 huggingface dataset:
On acoustic coupling of flextensional sonar projectors to vibration of nearby structures
Authors: Chandiramani Khushi L. , Brown Neal A.
Published: October 2005

The fundamental mode shape of a flextensional sonar projector, effective in transmission as well as reception, is such that while the central portions of the transducer, close to the minor axis of its elliptical cross section, are moving outward, the end segments, close to the major axis, are moving inward. This feature introduces a quadrupole component of radiation and reception to the transducer, along with a related enhancement of the high-wave number content of the radiated near field and the minor lobe receiving sensitivity. Effects of these changes are assessed on (i) increased resonant vibration of surrounding plate-like structures when the transducer is radiating, and (ii) increased flow-noise response of the transducer when receiving while on a moving platform. [Work supported by Naval Undersea Warfare Center under sponsorship of Office of Naval Research.]
Design strategies for quieter products
Authors: Lyon Richard H.
Published: October 2005

Quieter products can be realized by several strategies depending on the condition of the product. A product that is already in the marketplace has far fewer options than one on the drawing board (or CAD screen). Enclosures, isolators, and mufflers are effective and solve parts stocking problems, but they represent pure extra cost without product improvement. Redesign must be incorporated into the product cycle, and can provide combined advantages for both sound and other product attributes. Some examples of design procedures that lead to quieter products will be presented.
Optimization techniques in structural acoustic design
Authors: Cunefare Kenneth A.
Published: October 2005

This paper addresses optimization for the minimization of total radiated acoustic power from practical three-dimensional structures. Optimization techniques currently focus on developing coupled computational models for the structural and acoustic responses, in terms of certain controllable design variables. Typically, the computational tools for developing these models are finite element and boundary element methods. For a given assumed excitation, the coupled model is optimized to produce a minimum radiated power condition. This approach is computationally intensive, due to the need to explicitly solve for the total response at each design iteration. The recently developed concept of ‘‘exterior acoustic modes’’ may provide a means to significantly reduce the computational effort required for the acoustic portion of a response model, for frequencies below some coincidence frequency criterion. The exterior modes concept yields a greatly simplified objective function for total radiated power, as compared to an objective function obtained through other means. This paper discusses the current art, and presents the alternative approach using the exterior modes representation. Optimization of the mass distribution of a baffled finite plate is used as a benchmark problem.
Effects of localized interfacial damping on vibration transmitted through joints in component assemblies
Authors: Farstad Jerry E. , Singh Rajendra
Published: October 2005

Damping ratios of assembled machine structures are often significantly greater than those of the individual components from which they are assembled due to friction at the joints. In this paper, the effects of localized interfacial damping on vibration transmitted through joints in assemblies is examined. An analytical formulation based on a component modal synthesis approach is used. Because damping is concentrated at joint locations, the modes of assembled structures may be complex-valued. Consequently, a new modal synthesis formulation that permits the use of complex-valued component modes is developed. Assembly modal properties are obtained from a variational formulation in which the motion constraints at joint locations are enforced using Lagrange multipliers, which are equal to the interfacial forces and moments. Computing these from the assembly response provides an efficient means for calculating the mechanical power transmitted through the joints. An example case of an assembly of two lumped parameter oscillators connected by two joints is examined. The results indicate that localized damping has significant effects on transmitted vibration, with the effects being most significant at the higher frequencies and near the assembly natural frequencies. The effects of the relative magnitudes of damping coefficients at each joint on vibration transmitted through each are also examined.
Time-dependent oral articulator responses to jaw perturbation
Authors: Kollia H. Betty
Published: October 2005

It is an established notion that the actions of the articulators are functionally constrained during speech production. Articulator tasks toward attainment of a specific goal appear to be distributed to the structures involved. This implies a global organization of the speech motor control mechanism. The present kinematic study examines the time dependence of articulator responses to jaw perturbation. Jaw-lowering perturbations were applied randomly during speech with the use of a mandibular prosthesis. Following the perturbation the coordinative timing among the articulators was generally maintained. It appears that the responses of the articulators to perturbations of the jaw were differentially affected by the time of the load application of the jaw and appeared to depend on the temporal relation between the onset of the perturbation and the onset of the component speech event. These load-induced modifications were effected in a manner such that the adjustments performed to counterbalance the perturbation and attain the specified target (/b/ production) were carried out in a modulated way. The jaw was the major contributor of compensatory adjustments to its mechanical perturbation, while the lower lip and upper lip supplemented these modifications in an almost reciprocal manner. Of the articulator kinematic variables (displacement, velocity, and duration), velocity was most sensitive to the temporal onset of the perturbation. [Work supported by NIH Grant Nos. DC-00121 and DC-00594 to Haskins Laboratories.]
Characterization of fluctuations in a fundamental period of speech based on fractal analysis
Authors: Kobayashi Tetsunori
Published: October 2005

New parameters representing the naturalness of fluctuations in fundamental periods of speech are proposed. They are calculated from the intermediate parameters for the calculation of fractal dimension. This paper shows their strong relationship with the perceptional judgments using GRBAS. Fluctuations in the fundamental period are important for the naturalness of speech. Many researchers have been trying to quantificate the naturalness of fluctuation. Although some researchers insist on the effectiveness of the fractal dimension for this purpose, it is difficult to find the obvious correlation between the fractal dimension itself and GRBAS. However, the contours of the intermediate functions for the calculation of a fractal dimension such as Nk(r) [{number of pairs xi , xj such that ∥xi−xj∥<r}/ {number of points}2, where xi is a k-dimensional vector that consists of a k sequence of fluctuations] and D(k) [slope of the plots of (log(r),log(Nk(r))] apparently show the characteristic patterns for the abnormal samples. The experimental results show that the highgrade samples and the lowgrade samples are well separated in the space of the principal component of the vector (D(1)...D(k)...) and that the gentle slope of the plots of (log(r), log(Nk(r)) appeared in the middle is a sign of strained sample.
Ambient noise vertical and horizontal directionality during SWellEx-1
Authors: Hodgkiss W. S. , D’Spain G. L. , Richardson A. M.
Published: October 2005

SWellEx-1 (Shallow Water evaluation cell Experiment ♯1) was carried out in August 1993 west of Point Loma in approximately 200 m of water. During SWellEx-1, a MPL 48-element vertical array was deployed from the R/P FLIP. In addition, the McDonnell–Douglas two-dimensional seafloor array (USTS) was deployed nearby and cabled back to FLIP for data recording. As well as along-slope and cross-slope source tow events, several days of ambient noise data were collected with both arrays. Shipping noise varied substantially during this period due to fluctuations in traffic patterns. The focus of this paper is on the temporal evolution of ambient noise vertical and horizontal directionality during SWellEx-1. For selected data segments, dominant shipping sources will be identified geographically and the observed vertical and horizontal directionality related to source-array propagation characteristics. [Work supported by ONR, Code 321.]
Nonlinear excitation of collective oscillations of fresh and salt water bubble plumes
Authors: Orris Gregory J. , Nicholas Michael
Published: October 2005

Bubble plumes of various void fractions and sizes were produced by varying the flow velocity of a water jet impinging normally on a water surface. The bubbles entrained at the surface were carried downwards by the fluid flow to depths ranging from roughly 1.2 to 2.0 m, and formed roughly cylindrical plumes with diameters ranging from roughly 0.5 to 1.0 m. The acoustic emissions from the plumes were recorded onto digital audio tape using a hydrophone placed outside the cloud at distances ranging from 0.5 to 16.0 m. Closeup video images of the individual bubbles within the plume were also taken in order to gain knowledge of the bubble size distributions. The experiments were performed in both freshwater and saltwater environments. Most of the acoustic energy of this system is broadband and confined to frequencies below 1200 Hz, yet bubble size distributions do not show any appreciable number of bubbles large enough to account for the strong spectral signature at these low frequencies. The bubble entrainment is itself a nonlinear process. To investigate the possibility that the collective excitation (with fundamental frequencies characteristic of the gross dimensions of the plume) is driven by the broadband nonlinear entrainment, methods of nonlinear signal processing recently developed have been applied.
Analysis of North Atlantic bottom reverberation and examination of broadband effects
Authors: Smith Kevin B. , Hodgkiss William S.
Published: October 2005

High-quality experimental data were collected during the 1994 ONR-Bottom Acoustic Reverberation SRP cruise. Preliminary analysis with a cw PE solution shows good correlation between ensonification and reverberation. A broadband version of the UMPE model computes the time/depth domain solution at any given range. The presence of incoherent forward scatter is evident for various locations within the SRP Natural Laboratory in the vicinity of the mid-Atlantic ridge east of Bermuda using a 200×200-m gridded bathymetry database derived from a previous SRP geophysics cruise. By storing most of the range dependence of this solution, a transformation can be made to a complete set of time snapshots or ‘‘time fronts.’’ This analysis animates the pulse propagation through physical space and introduces new insights to the understanding and interpretation of bottom reverberation. A further extension of the BB-UMPE model provides a study of the frequency dependence of reverberation relative to small (∼λ) bottom roughness correlation length scales. [Work supported by ONR, Code 3240A.]
Comparison of acoustic model predictions with reverberation data from the ARSRP reconnaissance experiment
Authors: Chin-Bing Stanley A. , Murphy Joseph E. , Li Gongqin
Published: October 2005

Reverberation measurements from the mid-Atlantic ridge region were made during the Acoustic Reverberation Special Research Program (ARSRP) 1991 reconnaissance cruise. Ocean acoustic models have been used to investigate acoustic backscatter from a sedimented seafloor overlying an anelastic subbottom typical of this seafloor region. Computer simulations of the reverberant field were generated and compared with the ARSRP measured reverberation. Computer simulations were made using high-resolution ocean acoustic and seismoacoustic cw computer models. The parabolic equation model, fepe, was used to propagate the long-range acoustic fields to and from the vicinity of the mid-Atlantic ridge region, and the seismoacoustic finite-element model, safe, was used to determine the scattered fields from the rough seafloor and anelastic subbottom. Time-domain calculations were obtained from FFTs of the backscattered cw fields. Several realizations of the range-dependent sediment and subbottom were used. The bathymetric data for the sedimented regions were generated by the Webb–Jordan sediment distribution model. The bathymetric data for the subbottoms were generated by the Goff–Jordan fractal seafloor/basement model. The envelope of the simulated reverberation compared favorably with the measured reverberation data. Results support the conclusion that seafloor reverberation can be accurately simulated using high resolution ocean acoustic-seismoacoustic computer models together with high-resolution seafloor bathymetric data obtained from geomorphological models. [Work supported by the Office of Naval Research, Acoustic Reverberation SRP.]
Modeling deterministic features in the ARSRP acoustic data
Authors: Stephen R. A. , Shaw P. R. , Greaves R. J. , Caruthers J. W.
Published: October 2005

A preliminary study of the match-filtered beam data for the 5-s LFM chirps acquired on the Acoustic Reverberation SRP’93 acoustics cruise has been carried out. The analysis is based on a few selected segments which insonify site A at a 1/2CZ. The deterministic ‘‘bright spot’’ identified 2 years ago in the ’91 data set appears in the ’93 data. Although the characteristics of the event differ because of the different insonification parameters, the event appears in the same location when viewed from a number of azimthus and ranges. Other events within site A are robust when viewed from different ranges along the same azimuth, but disappear with changes in azimuth. The observations, which resolve left–right ambiguity and which account for insonification/bathymetry (TL) issues, indicate that backscatter is strongly dependent on azimuth. It is quite clear at site A that robust deterministic features are present in the 1/2CZ acoustics data. [Work supported by Office of Naval Research.]
Wide-area backscatter from the Mid-Atlantic Ridge experiment of 1993
Authors: Makris Nicholas C. , Avelino Lilimar , Menis Richard
Published: October 2005

The goal of the Main Acoustics Experiment of 1993 (MAE) is to reveal the fundamental scattering process responsible for long-range reverberation. The initial objective is to compare reverberation and geology measured at specific sites of morphology characteristic to the Mid-Atlantic Ridge. Previous analysis of data from the Acoustic Reconnaissance Cruise of 1991 (ARC) shows a high correlation between spatial charts of measured backscatter and modeled transmission loss (TL). Specifically, measured backscatter maxima correspond to modeled TL minima. These extrema are typically charted to ridges that protrude above the excess depth contour along scarps facing the observation and are most pronounced at n+1/2 convergence zone (CZ) ranges. Charted MAE backscatter shows similar behavior and the expected dependence upon TL. At least 50% of spatial variations in charted backscatter can be accounted for by TL. To properly register discrete backscatter returns with geomorphology, ambiguity in the towed-array data is eliminated by two independent techniques. The first optimally combines redundant backscatter observations made with differing array orientations to eliminate line-array ambiguity. This is possible because MAE tow-ship tracks were designed with ambiguity resolution as an essential theme. The second uses environmental symmetry breaking information available in modeled TL to resolve ambiguity.
Seafloor vertical array data collected during the July 1993 ARSRP bottom reverberation experiment
Authors: Hodgkiss W. S.
Published: October 2005

During the July 1993 ARSRP bottom reverberation experiment, the R/V Knorr deployed bottom-moored, 64-element, vertical line arrays (VLA’s) with the data being recorded by autonomous digital recording packages (GARRP’s). The R/V Knorr also deployed the NRL DTAGS (Deeply Towed Acoustics-Geophysics System) as an acoustic source and receiver and towed DTAGS in the vicinity of these seafloor arrays. Transmission time was shared between the three ships participating in the experiment (R/V Cory Chouest, R/V Alliance, and R/V Knorr). Thus, the VLA’s/GARRP’s and DTAGS recorded bistatic scatter from both the R/V Cory Chouest and the R/V Alliance during their respective transmission intervals. During DTAGS transmissions, DTAGS recorded her own scatter monostatically and the VLA’s/GARRP’s recorded the scatter bistatically. In this paper, selected segments of VLA/GARRP data from different experiment sites within the SRP National Laboratory will be shown and the received scatter related to the source-array positions and bathymetry. [Work supported by ONR, Code 324OA.]
Reverberation characterization and suppression by means of principal components
Authors: Slater Richard R. , Tufts Donald W.
Published: October 2005

A method of reverberation suppression and characterization, called the principal components inverse (PCI) method, has been used to separate strong components of the reverberation from the observed data of an active sonar reverberation experiment. The number of principal reverberation components needed to represent these strong components seldom exceeds three, illustrating the fact that, locally in time, segments of the reverberation waveform that have durations much shorter than a transmitted pulse can be represented as different linear combinations of the same two or three basis functions. These basis functions change as we move in time to some other local region. Because of the interest in the physical structure of reverberation, it is wished that the reverberation modeled by these basis functions be explained in terms of the physical components of reverberation models. The PCI method separates a beamformed acoustic signal into what the PCI method regards as a ‘‘strong reverberation component’’ and ‘‘other components.’’ Therefore both the received signal and the corresponding PCI estimates of the strong reverberation have been approximated by linear combinations of delayed, scaled, and Doppler-compressed replicas of the transmitted signal. It was found that the strong signal components of the observed reverberation and the PCI estimated strong reverberation match well.
Seafloor backscattering from explosive sources during the 1993 Mid-Atlantic Ridge experiment: Preliminary results
Authors: Berkson J. M. , Gibian G. L. , Richardson J.
Published: October 2005

During the Acoustic Reverberation Special Research Program (ARSRP) acoustic experiment of July 1993, an experiment was performed to identify seafloor scattering mechanisms. Explosive SUS sources were deployed on the western flank of the Mid-Atlantic Ridge to provide omnidirectional broadband sound for long-range reverberation measurements. In addition, pulsed cw tones in the frequency band 200 to 280 Hz from a vertical source array were used. The signals scattered by the seafloor were received by two 64-wavelength subapertures of a towed array, processed to form beam-time series, and then displayed as reverberation images on map projections. In order to obtain good signal-to-noise ratios, this analysis was performed in frequency bands of 4 Hz (time resolution 0.25 s) and then averaged to form beam-time series of 20-Hz bandwidth at harmonics of the bubble-pulse frequency. Initial results show that the cw measurements are consistent with the broadband results and that scattering strengths of specific seafloor features are generally constant over the frequency band 100 to 1000 Hz. [Work supported by ONR.]
Comparison of low-frequency acoustic backscatter data with model predictions using fine-scale geomorphology
Authors: Caruthers Jerald W. , Yoerger E. J.
Published: October 2005

Reverberation data were collected over the western flank of the Mid-Atlantic Ridge during the Acoustic Reverberation Special Research Program (ARSRP) cruises of 1991 and 1993. The site of the experiments included regions of large sedimented ponds and regions of large ridges of exposed rock with relief of 500 m in several miles. High-resolution bathymetry surveyed in the summer of 1992 and gridded to 200 m provided the geomorphology (i.e., bathymetry, slope, and slope bearing) with local slopes reaching 30°. Finer scale local bathymetric surveys in 1993 revealed higher sloped scarps, some of which were vertical. The reverberation data showed numerous highlights, suggesting the possibility of facet scatter from some of these scarps. The reverberation data, when smoothed to resolutions of several hundred meters, could be successfully modeled using a formulation of Lambert’s law with local grazing angle as the argument of the sine squared and the 200-m bathymetry providing the local slopes and slope bearings. The Lambert coefficient was found to vary over the region with dB values of −27 in sedimented regions and −17 in exposed rock regions. [This work is supported by the Office of Naval Research.]
Measurements and modeling of the spectral character of low-frequency, low grazing angle surface reverberation
Authors: Thorsos Eric I. , Gauss Roger C. , Soukup Raymond J. , Fialkowski Joseph M.
Published: October 2005

Measurements of low-frequency (200–1000 Hz) and low grazing angle (<10 deg) acoustic surface scattering were made in the Gulf of Alaska in February of 1992 [R. C. Gauss and J. M. Fialkowski, J. Acoust. Soc. Am. 93, 2299 (A) (1993); Gauss etal., J. Acoust. Soc. Am. 94, 1765 (A) (1993)]. Short- and long-duration waveforms were used to quantify the spectral character of surface reverberation as a function of frequency and environmental conditions. For moderate to high wind conditions, scattering from near-surface bubble clouds is expected to be the dominant scattering mechanism. This scattering process has been modeled, assuming point scatterers near the surface, representing the bubble clouds, are being convected in the orbital motion of the wave field. Measured 2-D surface wave spectra provided by J. Hanson [APL/JHU] are used to represent the wave field. This simple model is found to replicate reasonably well the spectral properties of the measurements, especially in high sea-state cases. Measurement/model comparisons will be presented. [Work supported by ONR.]
Seafloor insonification near the Mid-Atlantic Ridge
Authors: Lupien Vincent H. , Fricke J. Robert
Published: October 2005

As part of the Acoustical Reverberation Special Research Program (ARSRP), several at-sea experiments were performed near the Mid-Atlantic Ridge to understand low grazing angle backscattering from the ocean seafloor. Although the bathymetry for this region is known, the seafloor has not been classified into acoustically relevant types. In order to classify the seafloor according to its acoustical scattering properties, events in the backscattered signal must be co-registered with regions on the actual seafloor, and the propagation process must be modeled. A software package was developed that uses ray-tracing to yield the seafloor insonification patterns of receiving and transmitting arrays. This tool allows for arbitrary location and orientation of both arrays, an arbitrary sound-speed profile, and arbitrary beam patterns for both arrays. The end product is a set of surfaces representing the time delay, two-way transmission loss, and grazing angle (among other parameters) for each point on the known bathymetry. This step is key in extracting acoustical scattering types from the receiver signals. It is anticipated that the method will permit better utilization of the available data since sidelobe radiation is not neglected. [Work supported by ONR.]
Preliminary analysis from rapid-fire experiment over Whiskey Hole; ARSRP ’93
Authors: Fricke J. Robert
Published: October 2005

This paper presents a preliminary analysis of the rapid-fire data taken over Whiskey Hole during the Cory ’93 cruise. The data were collected at 90-s ping intervals to investigate variability between pings and to map the basement under the Whiskey Hole sediment pond. Analysis shows that the sediments at this site have a maximum thickness of 150 m. Over a range of grazing angle 30°<γ<90°, attenuation due to the sediments is modest, maximum of 3 dB, both over the pond and on the hill sides surrounding the pond. Heterogeneity of the sediments is unimportant. Surface waves effects are not seen in the data, which is discrete in both cross and along track directions. A scatterer density of O(10) per square kilometer is estimated with an average lineal spacing between scatterers of 250 m. Most of the data observed are vertically propagating multipath reverberation. In a small window near the beginning of the record direct scatter is seen. Also, occasionally in the late-time record a few high-energy direct scatter events are seen punching through the reverberant noise floor. [Work supported by ONR.]
A modulation model for the vowel sound /i/ in human speech
Authors: Hughes Tadd B. , Absher Richard G.
Published: October 2005

An approach has been developed that models a nonstationary speech signal with very low error on a pitch period by pitch period basis using an AM–FM model. The speech signal is first separated into two independent signals, a low-frequency signal and a high-frequency signal. AM and FM signals are extracted from the high-frequency signal through the use of two nonlinear operators, the integral operator and the overmodulation detection algorithm. Model parameters are determined by a combination of direct Fourier series computation and parameter optimization using the correlation error measure and the Marquardt–Levenberg algorithm. This technique was applied to speech produced in various gas concentrations of air and helium in order to determine whether model parameters are directly related to the velocity of sound ratio. It was found that the amplitudes of the harmonics of the low-frequency signal were emphasized with the increase of the velocity of sound ratio. The standard deviation of the carrier frequency of the FM signal tended to increase with the velocity of sound ratio. The amplitudes of the AM signal had a modal structure, and the modes were independent of velocity of sound ratio.
Underlying control strategies for the production of stop consonants
Authors: Poort Kelly L.
Published: October 2005

The underlying control strategies utilized in the production of stop consonants were investigated using an electromagnetic midsagittal articulometer [J. Perkell etal., J. Acoust. Soc. Am. 92, 3078–3096 (1992)]. The movements in the midsagittal plane of points on the lower jaw, lips, tongue blade, and tongue body were measured for three normal hearing, normal speaking subjects during the production of single-syllable words composed of a stop or nasal consonant followed by the vowel /ɑ / or /i/ and the consonant /t/, and spoken in a carrier phrase. Half the tokens were preceded by the fricative consonant /s/. The data show that the maximum downward velocity of the lower jaw occurs approximately at the time of the consonant release. For /sCV/ syllables, the lower jaw is held in a high position to assist in noise generation for /s/, and consequently the movement for a following labial or velar consonant follows a time course that is different from that of /CV/ syllables. The movement of the articulators during the production of these utterances at a normal speaking rate appears to have a bandwidth limitation of 5–7 Hz. [Work supported in part by grants from NIDCD.]
The effect of systematic speaking rate increases on lip and tongue coordination
Authors: Gleason Philip , Tuller Betty , Kelso J. A. S.
Published: October 2005

Previous work [Tuller and Kelso, Attn. & Perf. XIII (1990)] reported a transition in relative phase between glottal and lip movements as the rate of producing a VC syllable increased. However, the character of the transition could not be explored because of the large increments in rate selected by the speakers. Here, speaking rate was controlled using a metronome that began at 1 Hz and increased to 3.25 Hz in 0.083–Hz steps every 12 repetitions. Subjects repeated the target word ‘‘opt,’’ ‘‘hopped,’’ or ‘‘top’’ in time with the metronome while movements of their tongue tip, tongue blade, lower lip, upper lip, and jaw were tracked by an alternating magnetic field device, the Articulograph AG100. Analysis of the relative phasing between articulators confirmed the presence of a transition from VC to CV syllable structure at higher speaking rates. Results will be discussed with respect to the type of transition observed and the relative stability of different syllabic structures.
Measuring articulatory tract motion
Authors: Lenzo Kevin , Erickson Donna
Published: October 2005

A method for data analysis was developed to aid in processing x-ray pellet traces of articulatory tract motion. Segmentation criteria may be determined by constraints on the first and second derivative, and then selected segments are measured in terms of position, excursion distance, velocity, duration, and curve area measurements computed by Riemann approximation. Measurements currently encompass the segment as a whole, and the initial and final portions with respect to the maximum. An index is assigned to each segment. Parameters allow the user to generate values for only those regions involved in specific analysis tasks, to set the sensitivity of the first and second derivative zero-crossing algorithm, and to choose the right, left or center portion of the continuous regions that satisfies the derivative constraints often bracketing a true zero-crossing in order to more precisely define start and end measurements points. For instance, some mandible motion segments have smooth beginnings and endings, but others show edge perturbation, e.g., the word ‘‘five’’ sometimes shows a slope or plateau before the jaw movement drops into the vocalic valley. Some possible applications for this approach to measuring articulatory and other motion data are discussed. [This work has been supported in part by Shannon Award (NIDCD ♯1 R55 DC00015-01A1) and by a research fund from ATR, International, both given to O. Fujimura.]
Tongue movement mechanism in different speaking rates
Authors: Oshima Kiyoshi , Honda Kyoshi , Niimi Seiji , Gracco Vincent L.
Published: October 2005

In this paper tongue activity during Japanese speech production was examined. Of interest was the identification of potential neural control strategies and biomechanical contributions underlying speech production by evaluating, separately and in combination, kinematic and electromyographic (EMG) activity of the tongue at normal and fast speaking rates. Three normal adult Japanese speakers (three male) served as subjects for this investigation. Hooked-wire electrodes were placed in three tongue muscles; two extrinsic (genioglossus anterior [GGA] and genioglossus posterior [GGP]) and one intrinsic, and two facial muscles (orbicularis oris inferior [OOI] and depressor labii inferior [DLI]). The two-dimensional movement data were recorded electromagnetically on the midsagittal plane using an EMMA system [Perkell etal. (1992)]. Upper lip, lower lip, tongue tip, and tongue body movement were recorded simultaneously with the EMG data. Though a variety of speech tasks were recorded, the present report will focus on three syllable words, /poteto/, in a carrier sentence, /ii−desu/ at a normal speaking rate and a subject-determined fast rate. It was found that EMG and movement characteristics were maintained for both normal and fast rate. Although at a fast speaking rate, movement amplitude were reduced, EMG amplitude were either maintained or somewhat increased.
A head and transducer support system for making ultrasound images of tongue/jaw movement
Authors: Stone Maureen , Davis Edward P. , Lo Raulie
Published: October 2005

This paper will present a new head/transducer support system for use in ultrasound imaging of tongue movement. The head is stabilized by applying gentle resistance in directions opposed to its normal directions of motion (rotation, tilt, lean). The ultrasound transducer is immobilized below the chin, separated from the skin by a compressible gelatin-like standoff that allows free jaw movement without soft tissue compression. The system images the tongue/jaw unit. Previous transducer holders have attempted to measure tongue movement relative to jaw movement by allowing the transducer to move up and down with the jaw. This is satisfactory for the tongue tip, which is dependent on jaw position. It is not satisfactory, however, for the tongue root, which moves independently of the jaw. Therefore, this system does not attempt to separate tongue and jaw behavior, but measures them as a single unit. This new support system also introduces for the first time the normalization of tongue position relative to head position. To do this, a video image of the subject’s face is inserted in the image. Three marked points on a pair of eyeglasses are used to align tongue position across frames in case of head movement.
Gestural and prosodic influences on the articulation of consonant sequences
Authors: Byrd Dani
Published: October 2005

This study investigates several factors affecting articulatory timing and reduction in English consonant sequences. Electropalatography was used to record five speakers saying sentences containing a consonant cluster spanning a word boundary. Based on the EPG contact profiles, metrics were calculated indicating the overlap of the consonants and their spatial displacement, i.e., magnitude. The following results were obtained. (1) Coronal consonants are more overlapped by a following velar stop than a velar stop is by a following coronal. (2) A stop is more overlapped by a following consonant than is a fricative. (3) Movements in coda position are smaller than movements in onset position for stops but not for fricatives. (4) Movements in coda position are more variable than movements in onset position for stops but not for fricatives. Findings (3) and (4) suggest that variability may play an important role in reduction processes. In summary, these findings support the claim that speech coordination is affected by linguistic factors. These factors include both gestural influences—such as place and manner of articulation—and prosodic influences—such as syllablic position. This experiment provides significant data with which models of speech timing can be further explicated to more accurately reflect articulatory coproduction. [Work supported by NSF.]
Articulatory and acoustic variability of vowels in Japanese and English
Authors: Hashi Michiko , Westbury John R. , Honda Kiyoshi
Published: October 2005

Measures of formant frequencies and x-ray microbeam representations of partial mid-sagittal tongue contours were made at discrete moments in time for single tokens of each of five brief isolated vowels /i e a o u/ produced by seven native adult speakers of Japanese, and ten comparable speakers of American English. The broad purposes of these measurements were twofold: (1) to increase basic understanding of the relationship between articulatory postures and their acoustic correlates during production of isolated vowels; and (2) to develop preliminary estimates of the extent of articulatory and acoustical variability in vowel production in the two languages. The analysis of patterns among lingual contours achieved by different speakers raises problems regarding normalized description of vowel gestures. Methodological approaches to these problems, and their effects on descriptive summaries of the data, will be discussed. [Work supported by ATR Inf. Proc. Res. Labs. and NIH Grant No. DC00820.]
Korean to English articulatory mapping: Palatometric and acoustic data
Authors: Schmidt Anna Marie
Published: October 2005

Second language (L2) learners are thought to substitute phonemes from their first language for L2 sounds, at least during the early stages of learning. Palatometric data, coupled with acoustic data, can illuminate some details of cross-language articulatory mapping. The purpose of this study was to examine the articulation of some English consonants by a native speaker of Korean. Measures such as anterior/posterior placement were examined for eight repetitions of 14 English initial consonants (/θ, hooked schwa, f, v, s, z, t, d, l, n, r, ∫, t∫, dyog/) combined with each of three vowels (/i, a, u/). Results for the English consonants were compared with results for eight repetitions of Korean consonants (including three dental stops, two dental fricatives, three affricates, one dental nasal, and one liquid) combined with each of the same vowels. Most sounds not present in the Korean phoneme inventory (/f, v, γ, hooked schwa, r/) were produced with English-like articulation. Some English sounds that are perceptually similar to sounds in Korean were often produced with Korean-like articulation but were less consistent in placement than their Korean counterparts.
Articulatory changes following spectral and temporal modifications in auditory feedback
Authors: Gracco Vincent L. , Ross Dorothy , Kalinowski Joseph , Stuart Andrew
Published: October 2005

The influence of auditory information on the control of speech movements was investigated. The subjects acoustic signal was directed through a digital signal processor and feedback to the subject through a set of insert earphones. Experimental manipulation of the subjects auditory feedback included elevating the sidetone an octave and the introduction of a delay (100–150 ms). Two-dimensional motion of the lips, the mandible, and front and rear of the tongue were obtained electromagnetically during repetitions of single syllables, phrases, and short sentences. Kinematic measures were obtained for the normal auditory condition and the two experimental conditions. Modulation of the subjects feedback had pronounced effects on the temporal properties of the movements with rate being the most salient. Delaying the auditory feedback slowed down speaking rate while frequency shifting increased speaking rate. Articulatory changes were generally consistent with the changes in speaking rate. Changes were also noted in the subjects fundamental frequency. In contrast, formant frequencies were generally unaffected by the distorted auditory signal. The results will be discussed with regard to the auditory contribution to sensorimotor control of vocal tract actions and the characteristics of the underlying vocal tract targets.
Magnetic resonance imaging (MRI) in vocal tract research: Clinical application
Authors: Gracco Carol , Sasaki Clarence T. , McGowan Richard , Tierney Elizabeth , Gore John
Published: October 2005

This research demonstrates the application of three-dimensional analysis using MRI to study normal and abnormal aspects of speech and voice production. Subjects who undergo supraglottic laryngectomy often experience changes in vocal quality, even though the larynx is spared. Vocal tract area functions based on pre- and post-operative images and acoustic recordings demonstrate the correspondence between anatomy and acoustic product and quantify these categorical changes. Anatomically, the supraglottis is altered by removal of the base of tongue, epiglottis, and the false vocal folds. The correlation between changes in vocal tract shape and perceptual consequences relative to voice quality were assessed and quantified using three-dimensional reconstruction and computer assisted measurement analysis in addition to computer algorithms for assessment of glottal characteristics. For all subjects, changes in voice quality were highly correlated with specific variation in vocal tract area function and changes in the sound source at the glottis. The development of methods for studying the functional effects of surgical alteration of the vocal tract are highly relevant to clinical study as well as basic studies of the articulatory and acoustic processes. [Work supported in part by NINDCS/NIH Grant Nos. DC-00865, DC-01147, DC-00044, DC-00121.]
Exploiting a videodisc-based cineradiographic database for speech research
Authors: Tiede Mark K. , Vatikiotis-Bateson Eric
Published: October 2005

While cineradiography has been a staple of phonetics research for many years, making use of the results has relied on laborious and error-prone hand tracing of individual movie frames. The transfer of a representative selection of high-quality radiographic movies to laserdisc (a collaborative project of ATR and Queen’s University, Canada) has now made the application of standard video processing techniques to such data feasible on inexpensive microcomputers. The present research explores some of the possibilities inherent in this new look at old data: software capable of automatically reducing noise, detecting air-tissue boundaries, and tracking articulatory displacements (e.g., jaw, lips, tongue have been developed and will be demonstrated ) the results have been used to resynthesize close approximations to original vowel acoustics. The goal is to characterize tongue dynamics in terms of changes over time to a normalized parametrization of the tract surface profile, which this software permits one to derive automatically. This information will complement other modes for investigating speech production for which either dynamics or surface profiles are unavailable (MRI, magnetometer).
Production of speech from a physiological model of speech organs
Authors: Hirai Hiroyuki , Dang Jianwu , Honda Kiyoshi
Published: October 2005

A physiological model of laryngeal and supralaryngeal articulators has been designed based on the morphological data from MRI images. The model has a hybrid construction: a finite element method for tongue deformation and a mass-spring model for connecting other rigid structures by muscles. The posture of the model is determined by computing static equilibrium of muscle forces on all of the components, and is used to calculate the vocal tract areas and the transfer function of the model with reference to the MRI data. The cricothyroid angle determines parameters for the vibration of the two-mass model [Bell Syst. Tech. J. 51, (6) (1972)] and these source sounds are then fed to the model to generate synthesized speech. In this model, the kinematical connections among the jaw, the hyoid bone, the tongue, and the laryngeal cartilages represent so called tongue–larynx interaction that is observed in natural speech. The source-tract acoustic coupling also contributes to the naturalness of the output. The overall performance of the model for vowel production with various F0 levels has been tested by comparing the acoustic data from the model’s output and corresponding recorded speech.
Effects of medial olivocochlear efferents on responses of auditory nerve fibers
Authors: Guinan John J.
Published: October 2005

Stimulation of medial olivocochlear (MOC) efferents, either by shocks or sound, inhibits responses of auditory-nerve fibers (ANFs), as if the gain of the ‘‘cochlear amplifier’’ were decreased. Adding OC activity, in a quiet background, shifts the dynamic range of ANF responses to higher sound levels. The shift is typically largest for sounds near the characteristic frequency (CF), where the ‘‘cochlear amplifier’’ has its biggest effect, and for ANFs with mid- to high-CFs, where the MOC innervation is densest. In a continuous noise background, the response to a transient sound that is masked by the noise can be partially unmasked by MOC activity. By reducing the ANF response to the noise, OC activity reduces adaptation and can enhance the response to the transient, especially for transients well above the masked threshold. Antimasking is present for transient stimuli both near and off CF, however the noise must have energy near CF. MOC mediated anti-masking, which is a reduction of adaptive masking and should be most effective for mid- and high-frequency noise, will be contrasted with stapedius mediated anti-masking, which is a reduction of suppressive masking and is most effective for low-frequency noise.
Response properties of medial olivocochlear neurons: A sound-evoked reflex
Authors: Brown M. C. , Liberman M. C.
Published: October 2005

The responses of single medial olivocochlear (MOC) neurons have been studied in anesthetized animals. MOC neurons have low rates of spontaneous discharge (<20 spikes/s). Responses to tone bursts show sharp tuning with well-defined characteristic frequency and large dynamic range with maximum discharge rates of up to 150 spikes/s. In response to monaural stimulation, about 2/3 of MOC neurons response best to sound in the ear they innervate, the other 1/3 respond to sound presented contralaterally, and a small number respond to sound in either ear. However, virtually all response most vigorously to binaural stimulation. Single-neuron labeling shows projections from a single MOC efferent fiber span up to an octave of best frequency on the basilar membrane, with tonotopy similar to that of auditory-nerve fibers. The strength of the OC reflex in laboratory animals and humans has been assayed by measuring the suppression of response (compound action potentials or ear-canal emissions) produced by addition of contralateral sound, although care must be taken to anesthetized cat and awake human. [Supported by NIH Grants DC 01089, 00119, and 00188.]
The olivocochlear bundle and protection from acoustic overexposure
Authors: Liberman M. Charles
Published: October 2005

Activity in the olivocochlear bundle (OCB), either sound- or shock-evoked, has been reported to decrease the temporary threshold shift (TTS) produced by acoustic overexposure. For example, in anesthetized guinea pigs, a TTS of 40 dB measured after a 1-min, monaural exposure to a high-intensity 10-kHz tone could be reduced by 20 dB when simultaneous electric stimulation was applied to the OCB [R. Rajan, J. Neurophysiol. 60, 549–568 (1988)]. Interpretation of such data was challenged by experiments in which unilaterally de-efferented cats, binaurally exposed to high-intensity 6-kHz tones for 10 min while shocking the OCB, shows no interaural differences in TTS [M. C. Liberman, J. Neurophysiol. 65, 123–132 (1991)]. More recent experiments suggest this discrepancy arose because OC-mediated effects on TTS are only present for short-duration (∼1 min) exposure to high-frequency (10 kHz and above) tones. This OC mediated ‘‘protection’’ may be related to ‘‘slow’’ suppressive effects of OCB stimulation on cochlear responses, which are also most robust for high-frequency stimulation and for OC shock trains from 1 to 2 min in duration [T. Sridhar etal., Abstracts—XVIIth ARO Midwinter Meeting (1994)]. [Work supported by NIH Grant No. DC 00188.]
Effects of bilateral olivocochlear lesions on pure tone intensity discrimination in cats
Authors: May Bradford J. , McQuone Shelly J.
Published: October 2005

The effects of olivocochlear efferent lesions on intensity discrimination were examined in five cats. Cats were trained with food reinforcement to signal the detection of a change in the intensity of a pure tone by releasing a response lever. Intensity cues were conveyed by 1- and 8-kHz tone bursts in quiet and in the presence of continuous broadband noise. After the collection of baseline behavioral data, the olivocochlear bundle (OCB) was sectioned with bilateral knife cuts on the floor of the IVth ventricle. The completeness of OCB lesions was evaluated with cochlear acetylcholinesterase staining procedures. Although intensity discrimination was not negatively affected by OCB lesions when tests were conducted in quiet, performance deficits were noted when intensity discrimination was measured in the presence of noise. These data suggest that olivocochlear feedback may play an important role in the auditory processing of acoustic signals in noise backgrounds. Behavioral results will be discussed in terms of electrophysiological measures of intensity encoding. [Work supported by NIDCD Grant No. DC00979 and the W. M. Keck Foundation.]