bluuebunny/crossref_metadata_2025 huggingface dataset:
Speaker variability when producing repeated syllables and across speech tasks.
Authors: Kuo Christina , Weismer Gary
Published: October 2009

Target theory [Lindblom, J. Acoust. Soc. Am. 35, 1773–1781 (1963)] of vowel perception and production suggests that vowels have unique and characteristic articulatory and acoustic events that constitute the canonical forms (“targets”) of vowels. However, speakers do not always achieve these targets. There exists substantial variability in speech within a speaker and across speakers. Some of the challenges in understanding speech production lie in variability resulting from various factors including speaker identity, prosody, rate, and speech task. Because of the lack of data permitting good statistical estimates of target events, the following experiments were performed. First, within-speaker variations in consonant-vowel (CV) and vowel-consonant transitions in three monosyllabic words (dock, knock, and shock) during a sentence reading repetition task are evaluated for two speakers. Second, acoustic vowel targets in /h/-vowel-/d/ or-/t/ and selected consonant contexts (CV-/d/ or-/t/) are studied in the speech production of one individual across three speech tasks: citation, passage reading, and conversational speech. The hypothesis is a coarse-grained consistency with fine-grained variability in the acoustic signal and a continuum of changes in the acoustic vowel targets across tasks. Findings and continuing directions are discussed within the framework of target theory.
Kalman filter tracking of dolphin whistle countours.
Authors: Top Philip
Published: October 2009

The sounds of animals surround us daily with a cacophony of chirps, tones, and squeaks. For some creatures, underlying this symphony is a great deal of structure and potentially a complex communications channel. As one of the more intelligent creatures, the sounds of dolphins are of particular interest for further examination. Typical dolphin sounds consist of a series of broad spectrum pulses overlayed on narrowband signals that vary in frequency over time. The research in this study applies a branching Kalman filter to track the frequency varying spectral lines. The generated tracks can then be analyzed for features of interest, common characteristics, and structure as an initial step in potentially creating a decoder key.
Identifying individual clicking whales acoustically I. From click properties.
Authors: Ioup George E. , Ioup Juliette W. , Pflug Lisa A. , Tiemann Christopher O. , Bernstein Alan , Sidorovskaia Natalia A.
Published: October 2009

It has been observed that clicks within a single sperm whale coda have similar time and frequency properties, but these properties can differ from one coda to the next. Thus, it may be possible to identify individual sperm whales acoustically from the properties of their coda clicks. While sorting the codas by eye is promising, there is an obvious need to have automated identification by computer. Clustering methods present one appropriate approach to the identification of individuals. Although both K-means and self-organizing maps have been applied, the advantage of the latter, i.e., the ability to limit the number of clusters automatically, has favored its use. More recently, differences in echolocation clicks have become the basis of possible acoustic identification of individuals, also. Experiments by the Littoral Acoustic Demonstration Center in 2001, 2002, and 2007 as well as Detection, Classification, and Localization Workshop data have enabled extensive testing of these ideas. Results of the clustering for both types of clicks are encouraging. Localization and echolocation click rhythms have been used to verify the clusters. The identification has been extended to echolocation clicks of beaked whales. Illustrative results are presented. [Research supported by ONR and SPAWAR.]
Three-dimensional rough surface scattering using finite elements.
Authors: Joshi Sumedh , Isakson Marcia
Published: October 2009

In order to quantify the effects of three dimensional scattering, the scattering of a spherical incident wave from a rough, pressure release surface is modeled using a commercially available finite element (FE) code. The surface is generated by creating random realizations from a spatial power spectrum measured as part of the experimental validation of acoustic modeling techniques sea test conducted off the coast of Isola d’Elba in 2006. Since the FE model approaches an exact solution as the discretization density increases, it can be used as a benchmark for approximate methods. Therefore, the three-dimensional (3-D) FE model will be compared with a 3-D Kirchhoff approximation solution as well as two-dimensional solutions based on the integral equation, Kirchhoff, and FE models in order to determine the range of validity of the approximate methods.
The applicability of a small towed array system to the ocean bottom sediment classification problem.
Authors: Carey William M. , Lynch James F.
Published: October 2009

An autonomous array system is uniquely suited to perform near bottom (≈1 m) measurements of horizontal wave number spectra that estimate water and interface wave numbers. Synthetic coherent processing provides the required gain to observe the interface wave peak 40–50 dB below the peaks of water modes. Comparable measurements were performed with an array of seismometers (Muir et al., 1991). These spectra contain the information necessary to perform inversions that account for compressional and shear wave speed gradients. Spatial transforming the computed pressure field produces spectra comparable with measurements. Variations of the geoacoustic profiles show that the present gradient produces additional identifiable spectral structure corresponding to shear waves trapped within the sediments. In the experiments discussed, the sound source was at the bottom and the array was towed by a vehicle. However, it is feasible to either use a source of sound on the vehicle or on a companion vehicle to do surveys. This method is a fast, efficient, and accurate ocean acoustic measurement tool useful in rapid waveguide characterization with the appropriate inversion technology. (Work partially sponsored by ONR-OA.)
Relationships between intrinsic sediment attenuation, modal attenuation, and transmission loss in experiments over sandy-silty sediments.
Authors: Kaczkowski Stephen V. , Siegmann William L. , Carey William M. , Pierce Allan D. , Saintval Wendell
Published: October 2009

Numerous shallow water acoustic transmission experiments over sandy-silty bottoms demonstrate that the frequency dependence of intrinsic sediment attenuation at frequencies less than 1 kHz is nonlinear. Computational analyses including modeled geoacoustic profiles have shown that good agreement with experimental data can be obtained for frequencies between 50 Hz and 1 kHz. Upper sediment attenuation values for 1 kHz are in ranges specified by Hamilton [J. Acoust. Soc. Am. 68, 1313–1340 (1980)], and a nonlinear frequency dependent attenuation with power-law of about 1.8 is necessary. In this presentation, the relationship between the power-law exponent and modal attenuation coefficients is quantified for several nearly range-independent experiments in different locations. These include the Gulf of Mexico (1972), the Strait of Korea (ACT III, 1995), the New Jersey Shelf (1995), and Nantucket Sound (2005). The intrinsic sediment attenuation behavior with frequency and depth implies that modal attenuation coefficients may be obtained using parameters from the models of experimental environments. The behavior of range averaged transmission loss and the modal attenuations of contributing modes is examined. The former is shown to be less sensitive than the latter to parameter changes in the usual situation where the upper sediment layer is the primary source of attenuation. [Work partially supported by ONR.]
The effects of scattering and poro-elasticity in reflection coefficient measurements.
Authors: Isakson Marcia J. , Chotiros Nicholas P.
Published: October 2009

Reflection coefficient measurements taken as part of the experimental validation of acoustic modeling techniques experiment in October 2006 off the coast of Isola d’Elba, Italy display frequency dependent behavior that cannot be described using elastic reflection models and spherical wave effects alone. Furthermore, analysis of the effects of scattering based on measured interface roughness does not predict the critical and supercritical angle behavior. Therefore, a poro-elastic model is developed to account for the frequency dependent behavior. A comparison of the model including poro-elasticity, spherical wave effects, and scattering with the data will be presented. [Work sponsored by Office of Naval Research, Ocean Acoustics.]
Acoustic detection of mines buried in the sediment in shallow waters using a laser Doppler vibrometer.
Authors: Ekimov Alexander , Sabatier James , Aranchuk Vyacheslav
Published: October 2009

Naval operations in littoral regions require accurate methods and sensors to detect mines, thereby preventing injury to personnel and damage to equipment. Mines may be buried in the sediment in shallow waters, on beaches, or regions adjacent to the water. Acoustic detection of a mine buried in the seabed involves two major issues: exciting the vibration of a mine and measuring the vibration response of the mine and the environment. A small laboratory-like testing facility, a loudspeaker, and a laser Doppler vibrometer (LDV) were used in experiments to detect buried mines in sand and under water. Two possible scenarios for measurement of the vibration response of a mine and the environment were used: sensing vibration of the water surface and sensing vibration of the sand surface. The on-mine and off-mine mechanical impedances were measured with the LDV. The possibility of the transmission of the mine’s vibration to the surface of the water where it can be measured with an LDV was demonstrated. In these experiments, glass beads were suspended on the water surface to improve the reflected light returning to the LDV. Test results are presented and discussed. [Work supported by the Office of Naval Research Grant N00014-09-1-0016.]
Considerations related to the standardization of methods for the qualification of free field test environments.
Authors: Schmitt Jeff G.
Published: October 2009

The methods for qualification of acoustic free field environments, such as anechoic and hemi-anechoic chambers, have historically been defined in Annexes to the basic sound power standards, such as ISO 3745. However, free field test environments are used for many applications other than just sound power level determination, such as basic acoustic research, audio test, and hearing sciences. There currently are no general standards for free field qualification that addresses the unique needs of these test methods. Although the basic inverse square law qualification method is very straightforward theoretically, there are a number of practical considerations that can make this qualification method technically complex, logistically difficult, and expensive to implement. Industry standards must strike the right balance between the technical needs of the test methods and the costs associated with chamber qualification, particularly in the chamber vendor/chamber customer business environment. This paper will address some of the practical issues associated with the current inverse square law qualification method and the work of ISO Technical Committee 43, Working Group 8 that is currently in the process of developing a more general and improved document for the qualification of free field environments using this method.
Impulse response characterization of anechoic and hemi-anechoic chambers.
Authors: Nelson David A.
Published: October 2009

Characterization of a measurement environment is an important component of assessing measurement uncertainty. The traditional technique in anechoic and hemi-anechoic chambers is qualification through draw-away testing: deviation from square-law spreading is estimated along various radials, for broadband noise and occasionally for tones. All locations within a volume for which the deviations are below certain criteria are considered “qualified” for testing, and measured results from these locations are typically not corrected for the influence of the room. The draw-away test is tedious and time consuming and does not yield the information that is actually desired: precision of measurements for a particular source-receiver pair. Impulse response methods are considerably more rapid and provide a wealth of information in postprocessing including amplitude, phase, and time-delay factors for both steady-state and transient sounds, across arbitrary frequency ranges. This paper will explain how the impulse response characterization can be obtained and how it can be used to improve precision of measurements in anechoic and hemi-anechoic environments.
Tape as a surface protector for field tapping machine tests.
Authors: Wagner Alicia J. , Fullerton Jeffrey , Sacks Jonah
Published: October 2009

Impact sound transmission measurements of floor-ceiling constructions are often performed in the field. This leads to a wide range of testing environments; some of which can be high-end, multi-family residences with expensive floor finishes. Some residents can be concerned that testing may damage or scuff their floor. The ASTM e1007-04E1 standard does not discuss or provide allowances for acceptable methods of floor protection. This study investigates various kinds of tape including storage, masking, duct, and aluminum tape to find options that act as good surface protectors while minimally influencing measurement results. Testing was conducted on hard-wood and tile floors. Results will be shown comparing the impact sound transmission frequency spectra of the floors using each tape with the frequency spectra measured using the bare floor. Suggestions for modifications to future standards are proposed to address this concern.
Stanley Flatte: Atmospheric optics contributions.
Authors: Frehlich Rod
Published: October 2009

Stanley Flatte and his research group produced many key contributions to the field of atmospheric optics: both theoretical and based on numerical experiments. The results of numerical simulation of wave propagation through the random atmosphere (scintillation), the new theoretical predictions of scintillation statistics, and the implications of this work for understanding experimental results will be reviewed. Much of this work is based on techniques applied to acoustical problems of sound propagation in the ocean. The unique properties of the atmosphere that are responsible for the large magnitude of optical scintillation were revealed by these careful analysis. Theoretical predictions of basic scintillation statistics for many conditions of interest were found to be lacking. New applications, unresolved issues, and future directions of this research will also be discussed.
Amplitude and phase fluctuations of seismic waves and characterization of small-scale heterogeneities in the earth.
Authors: Wu Ru-Shan , Xie Xiao-Bi , Zheng Yingcai
Published: October 2009

Due to the limitation of sparse seismic observations on the earth’s surface, the deterministic picture of small-scale heterogeneities in the earth is difficult to obtain in general. Statistical characterization is a viable alternative to study the distribution and properties of the small-scale heterogeneities. The pioneering work of Aki in 1973 modeled the heterogeneities with a single-layer uniform random medium having only three parameters: scale, perturbation strength, and layer thickness. This simple model is consistent with the observations which are limited to only the transversal coherence functions of seismic wave (phase and amplitude) across an array and it has no depth resolution. The following work in 1970s and early 1980s were based on similar models. Flatte introduced the key idea of angular coherence functions using different earthquakes at large epicentral distances in the late 1980s (Flatte and Wu, 1988), which opened a new area of earth heterogeneity characterization by extending the single, uniform layer model to a depth-dependence model. Later, the angular coherence function was extended to the joint transverse-angular coherence function, which significantly increases the depth resolution of the heterogeneity spectra. In this talk, we summarize the research results along this direction conducted by a group of scientists in the earth science at University of California, Santa Cruz, collaborated with Flatte in different stages.
Single-path acoustic scintillation results from the Shallow Water 2006 Experiment.
Authors: Tang Dajun , Rouseff Daniel , Henyey Frank , Yang Jie
Published: October 2009

In “sound transmission through a fluctuating ocean,” Flattxe et al. described saturation of a single acoustic path as that path becoming a number of interfering uncorrelated micropaths due to refraction by internal waves. The probability density function of intensity becomes exponential with a scintillation index of 1.0. In deep water, however, full saturation is not achieved due to weak scattering and absorption. Mid-frequency (1–10 kHz) data from the Shallow Water 2006 Experiment are used to determine single-path intensity statistics. At a range of 1 km in water 80 m deep, an acoustic path is isolated that went through two upper turning points separated by a single bottom reflection. The data were collected during a period when large nonlinear internal waves were absent. The scintillation index calculated from the data increases with frequency until reaching a maximum of 1.2 around 6 kHz. It then decreases to 1.0, suggesting that single-path saturation can be achieved at mid-frequencies in shallow water. The probability density functions of intensity at various frequencies show a trend toward exponential. Because shallow water internal waves are dominated by the first mode, uncorrelated micropaths are an unlikely mechanism for producing the observed saturation. [Work supported by ONR.]
Sound transmission through the internal-wave field: The inverse problem.
Authors: Colosi John
Published: October 2009

Buoyed by the early success of ocean acoustic tomography for ocean mapping, and of path integral theory combined with the Garrett–Munk internal-wave model for explaining acoustic fluctuations, Flatte and others could not resist the temptation of using statistical moments of the acoustic field to learn something about the spatial and temporal distributions of ocean internal waves. Indeed, internal waves are of intense oceanographic interest because of their relation to tides, eddies (which account for 99% of the ocean kinetic energy), and the mixing processes that maintain the thermocline. Because of the integrating property of acoustics and the sensitivity of certain acoustic observables to different parts of the internal-wave spectrum, acoustical techniques like those described by Flatte offer a unique view into internal-wave behavior. Recent acoustic and oceanographic measurements made in the Philippine Sea using a large vertical aperture array and high temporal sampling may provide the first field demonstration of internal-wave tomography, progress of which would be quite pleasing to Flatte.
Observation of shallow water turbulences and model comparisons.
Authors: Yamamoto Tokuo , Badiey Mohsen
Published: October 2009

Observations of acoustic wave propagation through moving media reveal that the tidally generated turbulent currents occur around the clock. Only turbulent amplitude oscillates with geo-time. The Kolmogorov model of turbulent energy spectra and measured turbulent energy spectra is in good agreement. Turbulence is a poor conductor of gas because of thick bubble packed layer near the sea surface. Analytical solution shows strong vertical and horizontal circulations. It is anticipated that the bubble packed from the surface layer would be submerged into the turbulent currents. The turbulent energy data are compared with the internal wave energy. For most cases compared the turbulent energy is greater than that of the internal wave energy. From measured turbulent energy, the turbulence field and Reynolds stress field are obtained. The vertical and horizontal circulations in the turbulence are extracted using inverse methods.
Measurement and modeling of high-frequency acoustic channels for a moving source in shallow water.
Authors: Senne Joseph M. , Song Aijun , Badiey Mohsen
Published: October 2009

Acoustic systems used in underwater communications are sensitive to both scattering and Doppler shifts. In order to assess these sensitivities, an experiment (KAM08) was conducted during summer 2008 under variable environmental conditions. During the experiment, high-frequency (<10 kHz) acoustic signals were emitted from a towed source and measured by multiple hydrophone arrays moored in 100-m depth. Environmental parameters including wind, surface waves, and water-column temperature were collected concurrently with acoustic transmissions, which took place under variable sea states. Linear frequency modulated (LFM) signals and coherent m-sequence transmissions in the frequency band of 13–19 kHz were used to determine detailed channel characteristics for multiple source-receiver geometries. Both parabolic equation and ray-based models were run with moving source and simulated sea surface configurations in order to accurately reproduce experimental conditions. [Work supported by ONR 321OA].
Virtual time series experiment (VIRTEX) simulation tool for underwater acoustic communications.
Authors: Kim J. S. , Song H. C. , Hodgkiss W. S. , Siderius M.
Published: October 2009

Recently a virtual time series simulation tool for underwater acoustic communications, referred to as virtual time series experiment (VIRTEX), has been developed [Siderius and Porter, J. Acoust. Soc. Am. 124, 137–150 (2008)]. The code is based on time-varying impulse responses, capable of simulating the time series incorporating relative motion between a transmitter and a receiver as well as time-evolving moving boundaries. In this paper, VIRTEX is applied to KAM08 experimental environment to simulate the characteristics of acoustic transmissions under varying ocean conditions. Specifically, a comparison is made between KAM08 data and the simulated time series in terms of scattering functions that characterize Doppler and delay spreads along with representative channel impulse responses. It is found that VIRTEX can be useful for designing and planning communication experiments and evaluating the performance of communication systems.
Closed-loop adaptive feedback control of cavitation during high-intensity focussed ultrasound therapy.
Authors: Hockham Natalie , Arora Manish , Coussios Constantin-C
Published: October 2009

Prior experimental evidence indicates that the occurrence of inertial cavitation at the HIFU focus enhances the local rate of heat deposition, due to increased absorption of the broadband emissions associated with collapsing bubbles. However, initiating and sustaining cavitation activity throughout HIFU exposure remain a major challenge. Previous open-loop attempts at maintaining cavitation activity by varying the HIFU pulse duration have necessitated the use of duty cycles on the order of 20%, which are too low to achieve ablative temperatures. The present work presents the design, validation, and testing of a real-time closed-loop adaptive controller for sustaining thermally relevant cavitation within the HIFU focal region at duty cycles in excess of 95%. During 1.067 MHz HIFU exposure of an agar tissue-mimicking material, cavitation activity is continuously monitored and quantified using a single-element broadband passive cavitation detector (PCD) positioned coaxially with the HIFU transducer. The HIFU amplitude is adaptively modulated in direct response to the PCD signal, making it possible to maintain cavitation activity and a temperature rise in excess of 30 °C for more than 30 s. Most importantly, the acoustic energy needed to achieve such focal heating is only a fraction of that required in the absence of cavitation control.
Ultrasound and ultrasound contrast agent induced angiogenesis: A survival study.
Authors: Johnson Chenara A. , O’Brien William D.
Published: October 2009

Ultrasound (US) and ultrasound contrast agents’ (UCAs), ability to induce a particular bioeffect, angiogenesis, has been explored as a means of restoring blood flow to ischemic muscle. Determining the progression of the angiogenic response and how the acoustic pressure affects that response are integral to the evaluation of bioeffects, US therapy development, and understanding the physical process. Because UCAs demonstrate an increasing percentage of collapse with increasing US pressure, this study explored the effects with a high percentage of UCA collapse (i.e., high US pressure). Angiogenesis was examined in terms of capillary density in rat gracilis muscle (N=21) using H&E, and two immunohistochemical stains: CD-31 and CD-34. Several survival groups (0, 3, 6, 13, 20, and 27 days) were used to determine when the capillary density returned to normal levels. Inflammation cells were also quantified via a color threshold analysis as a percentage of the total section. When compared to the control, high US pressure and UCAs caused capillary density to decrease by 39% and inflammation cells to increase by 30–175% of the inflammation cells at day 0. These values returned to normal levels within 3–6 days. (Work supported by NIH Grant No. R37EB002641.)
Tissue heating in vibro-acoustography.
Authors: Chen Shigao , Alizad Azra , Aquino Wilkins , Urban Matthew , Greenleaf James , Fatemi Mostafa
Published: October 2009

Vibro-acoustography (VA) is an imaging method based on ultrasound radiation force. In this method, a two dimensional image is formed by scanning two co-focused ultrasound beams with slightly different frequencies over the object (biological tissue) in a C-scan format and recording resulting sound that is emitted from the focal region at the difference frequency. As in other ultrasound-based imaging modalities, it is important to study the thermal safety of the technique. This paper addresses tissue heating due to a VA scan using a concentric confocal transducer. The three dimensional ultrasound intensity field calculated by Field II is used with the bio-heat equation to estimate tissue heating. Results calculated with thermal conduction and with blood perfusion, with conduction and without perfusion, and without conduction and without perfusion are compared. Maximum temperature rise occurs in the transducer near field during VA scans. Heating during one VA scan is below 0.05 °C for soft tissue with attenuation coefficient of 0.3, 0.5, or 0.7 dB/cm MHz. It is concluded that temperature rise in tissue is not significant. [Work supported by NIH Grants CA 91956, CA 127235, and CA121579. Some of the techniques are patented by Mayo Clinic and the some of the authors (M.F. and J.F.G.).]
Sustainable design for audio, video, and broadcast facilities.
Authors: Berger Russ , Schrag Richard
Published: October 2009

Meeting sustainable design goals in facilities that include technical production spaces for audio, video, or broadcast presents special challenges to the design and construction team. Materials selections and sources affect not only the acoustical finishes, but may also influence larger building systems. Daylighting goals must be balanced with appropriate acoustical isolation. The integration of alternative chilled air delivery systems and lighting sources must be weighed against critical technical function. As a result, the acoustician’s role should expand to include an understanding of the sustainability goals, the impact of acoustical design recommendations, changes to the specification process, and the necessary coordination efforts with the rest of the participants. Examples from radio and television broadcast facilities, music recording studios, and performance spaces are given.
Thinking holisitcally about sustainability, acoustics, and architecture.
Authors: Giegold Carl P. , Pfeiffer Scott D.
Published: October 2009

Highly rated sustainable buildings invariably incorporate energy conservation concepts that come into conflict with tried and true approaches to interior acoustics, isolation, and noise control. The use of concrete slabs for energy storage exposes hard surfaces where we often want soft ones, natural ventilation opens rooms to each other and to often noisy, urban environments, and even seemingly benign concepts like chilled beams can end up replacing one kind of noise with another. Even so, sustainable approaches often have characteristics that are beneficial in acoustic terms, not least in its potential for reducing or eliminating sources of equipment noise. Current turmoil in the design professions as they search for better ways to embrace and explore sustainability presents an opportunity to install greater awareness of the aural world into the built environment. Through architectural case studies both built and in-progress, we look at examples of how interior acoustics and noise control have been approached in ways that solve aural, visual, and environmental challenges holistically.
Assessing acoustic measures of the spontaneous phonetic imitation of vowels.
Authors: Babel Molly , Munson Benjamin
Published: October 2009

It is well established that people imitate fine phonetic detail of another talker in shadowing tasks [Goldinger, Psychol. Rev. 105, 251–279 (1998)] and in interactive conversation [Pardo, J. Acoust. Soc. Am. 119, 2382–2393 (2006)]. That is, the acoustic characteristics of a model talker’s production (MTP) are more similar to a participant’s shadowed production (PSP) than they are to that participant’s baseline production (PBP), typically elicited in a reading task. This presentation compares two methods of assessing the acoustic distance between the vowels in PSP and PBP monosyllabic words taken from two previous studies [Babel, thesis, University of California (2009); Kaiser & Munson (unpublished)]. One of these measures is the F1/F2 Euclidean distance between PSP and PBP vowels. This measure does not take into account the direction of the difference. The other [adapted from Titze, Principles of Voice Production (1994)] compares the distance and direction of the F1 and F2 values in the PSP and PBP vowels relative to those of the MTP. The merits of each of these methods are assessed by comparing them to measures of listener judgments of the similarity of PSPs and PBPs to the MTPs in AXB perception tasks.
Tone-glottal coarticulation in a complex tone language.
Authors: DiCanio Christian T.
Published: October 2009

A majority of the research on coarticulation has focused on consonant and vowel timing, but work on the coarticulation of tone or phonation-type contrasts has received relatively less attention until recently [Brunelle (2003); Miller (2007); Peng (1997); Silverman (1997); Xu (1994); (1997); (1998); (1999); (2004); (2005); Xu et al. (2006); Xu and Liu (2006); Xu and Sun (2002); Xu and Wang (2001)]. The present work investigates the coarticulatory timing relationships between the nine tonal contrasts and three laryngeal contrasts (creak, glottal closure, and breathiness) of Itunyoso Trique [DiCanio (2008)]. Acoustic and electroglottographic (EGG) data from Trique were collected, comparing the realization of the tones in the different laryngeal conditions. While creaky phonation induces an equivalent pitch lowering for a variety of tones, breathy phonation induces pitch lowering in an asymmetrical fashion where higher tones have a greater pitch decrease than lower tones. These particular effects are not predictable from a perceptually-driven model of coarticulation, but accord well with the body-cover model of vocal-fold vibration [Titze (1994); Story & Titze (2003)]. The timing of non-modal phonation in Itunyoso Trique reflects a language-specific coarticulation strategy, but the observed pitch perturbation effects are best-explained with a speaker-oriented model of coarticulation.
Burial depth spatial decay rate reduction using bistatic detection: Laboratory demonstration.
Authors: Marston Timothy M. , Espana Aubrey L. , Thiessen David B. , Marston Philip L.
Published: October 2009

For some situations evanescent waves are important in the detection of objects below the sea floor. The scattering by the object is reduced for increased burial depth and the spatial decay rate of the scattering depends on the grazing angle of the incident wave as well as the grazing angle of the receiver (for the case of bistatic reception). The decay rates are related by extended reciprocity [Cerruti et al., J. Acoust. Soc. Am. 125, 2732 (2009)]. The present research gives laboratory measurements of bistatic scattering by two types of small targets (a liquid filled shell and an aluminum cylinder) in an experiment using immiscible liquids [Osterhoudt et al., IEEE J. Ocean. Eng. 33, 397–404 (2008)]. With a receiver position analogous to one in the water column nearly directly above a buried target, as predicted, the measured spatial decay rate of the scattering becomes simply that of the evanescent wave. Design of the experiment and placement of the hydrophone required computational simulation to reduce complications from tank wall reverberations. [Work supported by ONR.]
Modular classroom acoustics: Where we are and where we should be going.
Authors: Philipp Norman H. , Wang Lily M.
Published: October 2009

This paper presents a review of an 18-month study into the acoustical characteristics of modular (or relocatable) classrooms within the Omaha Public School District in Omaha, NE. The study included measurements of reverberation times, interior background noise levels (both occupied and unoccupied), and exterior facade sound insulation properties. From analysis of the gathered data, recommendations are made regarding sound insulation classification systems and background noise levels for the renovation of existing modular classrooms. These results may be used to inform the pending addendum to ANSI S12.60-2002, regarding acoustic guidelines for modular classrooms. Suggestions for future research are also discussed.
Current trends in K-12 classroom design.
Authors: Molter Jessica , Hodge Jonathan
Published: October 2009

Presentation of current trends in K-12 Classroom Design with an emphasis on items that contribute to acoustic performance of the space.
Seabed sound speed and attenuation from broadband acoustic measurements in the Shallow Water 2006 experiment.
Authors: Wan Lin , Zhou Ji-Xun , Rogers Peter H. , Knobles David P.
Published: October 2009

In the Shallow Water 2006 experiment, a set of broadband combustive sound source (CSS) signals was measured by two L-shaped arrays separated by 20 km on the New Jersey continental shelf with a water depth of around 72 m. The measured CSS data, which exhibit modal dispersion, are utilized to infer values for the seabed sound speed and attenuation. The seabed sound speed is estimated by matching the theoretical and measured modal dispersion curves, which are extracted using an adaptive time-frequency analysis technique. The frequency dependence of the seabed attenuation is inferred by minimizing the difference between the theoretical and measured modal amplitude ratios in the 50–400-Hz band. The resultant seabed attenuation is similar to the low-frequency seabed attenuation data obtained at 20 locations in different coastal zones around the world by Zhou et al. [J. Acoust. Soc. Am. 125, 2847–2866 (2009)]. The depth dependence of the seabed attenuation will be discussed. [Work supported by the Office of Naval Research.]
Rapidly changing ocean pH and the increasing transparency of the ocean to sound.
Authors: Brewer Peter G.
Published: October 2009

The intrinsic sound absorption coefficient (á, dB/km) of seawater is pH dependent with significant effects at 10 kHz and below. Ocean pH is declining from fossil fuel CO2 invasion, from excess nutrient input, and from climate change reducing ocean ventilation. These effects produce reductions in ocean borate and carbonate species such that an ∼18% decrease in á in the upper ocean has occurred today. Reasonable projections based on IPCC scenarios predict changes of 40% or more by mid-century [Hester et al., Geophys. Res. Lett. 35, L19601 (2008)]; larger changes in the sound channel are very likely. The projected increased transparency of the ocean to sound has attracted strong international environmental attention, and also provides an opportunity for acoustic detection and monitoring of such changes over large ocean regions. How strong is the basis for such assertions, can they be tested, and how well can environmental effects be predicted? This tutorial shows that the rate of change in pH in the sound channel has been underestimated, and how the unusual 1970s era reliance on the Soviet Gorshkov atlas as a pH data resource came about. This now presents a challenge for convergence of modern acoustic, environmental, and global change needs.
Multidomain modeling of a variable reluctance transducer.
Authors: Thompson Stephen C.
Published: October 2009

The variable reluctance magnetic transducer consists simply of a magnetic air gap and a magnetic return path that are supplied with static and dynamic sources of magnetic flux. The dynamic flux is generated by a coil current. The static flux may come either from a permanent magnet or a coil. The attractive magnetic force across the gap is modulated by the dynamic flux to provide the mechanical excitation for the device. The variable reluctance device is fundamentally nonlinear for at least three reasons: (1) the mechanical force across the gap is a quadratic function of the total magnetic flux, (2) the changing gap dimension changes the reluctance in the magnetic circuit so that the flux does not change linearly with coil current, and (3) saturation of the magnetic circuit may be an important aspect of the design that must be included in the modeling. In practical cases, the dynamic variation in gap dimension is large enough that a linearized approximation is insufficient to predict the performance. An approximate model using a set of nonlinear differential and algebraic equations will be discussed that can predict the stability and performance of variable reluctance transducers.
Lead magnesium niobate-lead titanate solution based giant-piezoelectric crystals for next generation of acoustic transduction devices.
Authors: Han Pengdi
Published: October 2009

The PMN-PT (binary solid solution of lead magnesium niobate and lead titanate) based piezoelectric crystals have been commercialized now. The giant-piezoelectric crystal can be broadly utilized for the next generation of acoustic transduction devices. In this paper, the major concepts and current status of the crystals and products will be presented and discussed in terms of applications. Following a brief review on the history of development of crystal growth and commercialization in the past decade, the detailed physical properties of the PMN-PT and newly developed PIN-PMN-PT crystals (high depoling temperature and high driving field) are presented and discussed in terms of applications in ultrasound transducers. At present (001)-seeded single crystals of 3 and 4 in. diameters are commercially available. In order to sufficiently utilize the advantages of the crystals, discussions focus on the following: (1) The differences between single crystal and PZT ceramics. (2) The concept of so called “domain-engineering” (artificially domaining) in context of elasto-piezo-dielectric matrices. (3) The relationships between the property and ferroelectric domain structure. (4) How to select the crystal products. In summary, the achievement of the development and fabrication of the giant-piezoelectric crystals has led to a new era that there are new opportunities readily to be explored for the next generation of acoustic transduction devices.
High-power single crystal based projectors.
Authors: Meyers Richard J. , Markley Douglas C. , Allen Charles W. , Sherlock Nevin P.
Published: October 2009

Significant progress has been made at integrating single crystalline relaxor ferroelectrics into many types of SONAR transducers. For high-power projectors, PMN-28PT has offered efficient, broad band-width capability. For higher duty cycles, thermal limitations are reached resulting in power and duty cycle tradeoffs. Electrical bias is also required for crystal implementation when high-power operation is needed. Continuing research in compositional tailoring has resulted in several new modified relaxor crystal systems with improved temperature stability, lower loss, and higher coercive fields. PIN-PMN-PT ternary crystals are of particular interest. This ternary system offers 25–40 °C improvement in working temperature, reduced temperature sensitivity, and approximately two times increase in coercive field without sacrifice in electromechanical coupling or piezoelectric coefficients. To demonstrate the impact of this newer ternary crystal composition on high-power transduction, planar tonpilz arrays were fabricated and tested. This presentation will highlight important material properties and compare the results of high-power measurements of single transducer elements and arrays made from PMN-28PT and PIN modified ternary crystals. Acoustic tests were conducted as a function of ambient temperature, increased drive level, and increased duty cycle operation. [Work supported by ONR.]
Toward a better understanding of high intensity focused ultrasound therapy using the Khokhlov–Zabolotskaya–Kuznetsov equation.
Authors: Crum L. A. , Canney M. S. , Bailey M. R. , Bessonova O. V. , Khokhlova V. A.
Published: October 2009

High intensity focused ultrasound (HIFU) therapy is an emerging medical technology in which acoustic pressure amplitudes of up to 100 MPa are used to induce tissue ablation, often in combination with real-time imaging. The ultrasound energy is typically focused into a millimeter-size volume and used to thermally coagulate the tissue of interest while ideally sparing surrounding tissue. Nonlinear effects are important in HIFU as in situ intensities for clinical applications of up to 30 000 W/cm2 have been reported. Since controlled experiments are often difficult to perform, especially in vivo, modeling can aid in understanding the physical phenomena involved in HIFU-induced tissue ablation. The Khokhlov–Zabolotskaya–Kuznetsov (KZK) equation is applicable to HIFU because it includes all of the basic physical phenomena that are relevant to HIFU including acoustic beams, diffraction, focusing, nonlinear propagation, shock formation, and dissipation. In this paper, an overview of several recent advances in KZK modeling for HIFU applications are described. It is shown that shock-induced heating in tissue can cause localized boiling in milliseconds; furthermore, the bubbles associated with boiling can significantly alter HIFU treatments. [Work supported in part by NSBRI SMST01601, NIH EB007643, and RFBR 09-02-01530.]
Talking heads: Speech synthesis and embodied cognition.
Authors: Rubin Philip , Ramsay Gordon , Vatikiotis-Bateson Eric
Published: October 2009

This presentation provides a brief overview of 300 years of effort toward the creation of talking heads: mechanical, electronic, and/or computational models of human speech. Speech, language, communication, and cognition are fundamentally shaped, in part, by both biological and physical factors. To understand this grounding and how to effectively replicate its most salient aspects in synthesis systems requires us to pay serious attention to the structure, kinematics, and dynamics of the articulators; the organization and characterization of complex, emergent behavior in multimodal systems; and the consideration of how events within such systems unfold over multiple time scales. New approaches that will help advance our knowledge and improve our synthesis tools and techniques will be discussed.
Space-time-frequency analysis of the scattered acoustic wave field from elastic shells recorded by bistatic sonar systems.
Authors: Sabra Karim G. , Anderson Shaun D.
Published: October 2009

An ongoing challenge for underwater sonar systems is to discriminate a man made target (shell) from surrounding clutter returns and to provide robust classification features for the estimation of the physical target characteristics (e.g., shell thickness and material properties). To this end, time-frequency analysis, and, in particular, Wigner–Ville analysis, has been shown to provide a robust processing tool for interpreting the evolutional time dependent aspect of the scattered acoustic wave field from elastic shells. The design of a robust space-time-frequency bistatic sonar system to enhance the target detection of shells with the use of a sensor array will be presented. Practical implications for bistatic mine countermeasure sonar systems, using a network of autonomous underwater vehicles, will be discussed.
Temporal analysis of human motion signatures.
Authors: Ekimov Alexander , Bradley Marshall , Sabatier James
Published: October 2009

Passive and active signals characterize human motion. Passive signals produced by footsteps are recorded with microphones and geophones. Active signals are measured with Doppler techniques and characterize the oscillatory motion of human body parts with different acoustic cross-sections and velocities. Simultaneous measurements of human passive and active signatures show temporal synchronization. This synchronization results in equal cadence frequencies for human motion signatures. These signatures are compared to a mathematical model of human motion [Boulic et al., “A global human walking model with real-time kinematic personification,” Visual Comput. (1990)]. This empirical model predicts the motion of key body parts including shoulders, elbows, fingers, hips, knees, and toes for an “average” human walking at a constant velocity. Speeds of the body parts depend on the walking velocity and the size of the individual as parametrized by thigh height. Comparison of experimental data with the predictions of the mathematical simulations enhances the capability to characterize humans. Measurements of the motion signatures of walking humans using a multimodal sensor suite (seismic, passive, and active ultrasonics, and radar sensors) are presented and discussed. [Work supported by Department of the Army, Army Research Office Contracts W911NF-04-1-0190 and W911NF-08-1-0389.]
Ray versus mode differences in reverberation modeling solutions for environments with high boundary scattering loss.
Authors: Thorsos Eric I. , Henyey Frank S. , Yang Jie , Reynolds Stephen A.
Published: October 2009

Several of the problems for the first Reverberation Modeling Workshop yielded interesting differences between solutions obtained with ray and normal mode methods. These particular problems were defined with high boundary scattering loss. A bottom reverberation case at 3.5 kHz with a down-refracting sound speed profile (Problem VI) will be considered as a case in point. The ray solutions show a “direct path” contribution unaffected by the bottom scattering loss as long as a direct path can reach the bottom, while the mode solutions obtained to date show a lower reverberation level during this period due to modal attenuation. These differences occur in both incoherent and coherent reverberation solutions for both rays and modes. Arguments will be presented that indicate the correctness of the ray solutions for this case. Suggestions will also be made on how the mode approach can be used to obtain solutions in agreement with the ray method. [Work supported by ONR and the Navy Program Executive Office C4I (PMW 120).]