bluuebunny/crossref_metadata_2025 huggingface dataset:
Acoustic variability in the speech of second language learners of American English as a function of accentedness
Authors: Smith Bruce L. , Hayes-Harb Rachel
Published: May 2014

The primary issue of interest in the present study concerned acoustic variability among L2 learners of English with different degrees of accentedness. Specifically, we were interested in determining whether L2 learners with stronger accents differ from L2 learners with weaker accents in terms of the amount of within-subject variability they manifest when producing English consonants and vowels. Twenty L2 English learners from nine different L1 backgrounds and a group of 20 native English control subjects produced a number of target sounds contained within CVC words that were embedded in a carrier phrase. Accent ratings for the twenty L2 talkers were obtained, and acoustic measurements were made of various consonants and vowels; coefficient of variation [(S.D. ÷ mean) × 100] was also computed for each of the acoustic measures. A number of temporal and spectral comparisons were made between L2 talkers with stronger versus weaker accents and with the native control subjects. Results indicated that although L2 subjects with stronger accents sometimes showed greater inter-subject (i.e., group) variability, they did not typically show more within-subject (i.e., token-to-token) variability than subjects with weaker accents, regardless of how accurate they were in producing native-like consonants and vowels.
Spontaneous speech variability across languages: Labial and velar stops
Authors: Warner Natasha L. , Simonet Miguel , Tucker Benjamin V. , Brenner Dan , Hoffmann Maureen , Baltazar Alejandra , Morales Andrea , Diaz Yamile
Published: May 2014

Stops such as /ptkbdg/ are perhaps the most-studied type of consonant in all of phonetics, and they have well-defined acoustic properties that one expects to find in a typical pronunciation. However, casual spontaneous speech reveals highly variable realizations of stops, ranging from voiceless stops with silent closure, burst, and aspiration noise, to weak approximants with only a slight weakening of formants, to deletion. Even careful speech reveals considerable variability. We examine acoustic realizations of intervocalic stops in Dutch, Spanish, Japanese, and English, as well as the L2 English speech of the native Dutch, Spanish, and Japanese speakers. For each speaker, we measure data from spontaneous casual conversation and from careful word-list reading. In this presentation, we focus on realizations of /pbkg/. Preliminary results indicate that Dutch speakers variably transfer word-final devoicing of Dutch voiced stops to their English /bg/, but that they do not rely on the Dutch /x/ (orthographic “g”) as a source of their English /g/. Results also show that Spanish /bg/ in conversation are almost categorically approximants or nearly deleted. Spanish speakers, especially those who learned English late, appear to apply this pronunciation to English consonants as a reduced speech style.
The rhythm of Aviation English by Native American English speakers
Authors: Trippe Julia , Pederson Eric
Published: May 2014

Air traffic controllers (ATC) and pilots at international airports must speak Aviation English (AE). Native and non-native English speakers alike must learn and effectively communicate using this technical language based on standard English. This project calculates the rhythmic profile of Native Speaker Aviation English (NSAE), which serves as the target for learners of AE and against which potential communication failures can be evaluated. NSAE rhythmic profile can be contrasted with the first language (L1) prosody to evaluate learner AE production and model training methods for specific L1 AE learners. NSAE generally exhibits flat intonational contours, so we focus on rhythm metrics. Our previous study’s findings demonstrated that NSAE metrics pattern differently than standard American English, falling between “stress-timed” and “syllable-timed” languages. Rhythm metrics based on consonant and vowel duration are affected by AE’s lack of function words (i.e., fewer reducible vowels), standard phraseology (producing prosodic chunking), and rapid speech rate (reflecting compressibility differential between vowel and consonant segments). We are training an automatic speech aligner to segment ATC NSAE and calculating a baseline for American NSAE using qualitative metrics (Ramus 2000; Low et al., 2000; Dellwo 2006). We will present our findings on how NSAE patterns with similarly evaluated languages.
The potential segmental influence of Taishanese (first language) on English (second language) intelligibility
Authors: Mai Tracy , Wang Emily
Published: May 2014

This study examined the influence of segmental differences in Taishanese Chinese on English speech intelligibility. There are over half a million Taishanese speakers in the United States. However, very little is known about the linguistic interference between the two languages. We hypothesized that the English speech intelligibility of Late Bilingual speakers would be significantly reduced by the interference of their first language of Taishanese. Furthermore, the main source of their reduced speech intelligibility would be the segmental interference from the Taishanese on English. Speech data from a focused set of vowels and consonants as well as controlled spontaneous speech were collected from three different Speaker Types: Late Bilinguals (4), Sequential Bilinguals (2), and Monolingual English speakers (2). Acoustic analyses and perceptual experiment were conducted. The primary outcome measures were perceived speech intelligibility and mean Number of Real Words (NRW) per utterance. The secondary outcome measures were duration and formant frequencies of vowels, VOT for syllable-initial stops, and syllable duration of syllable-final stops. The results showed that the Late Bilingual speakers had significantly reduced English speech intelligibility (p < 0.01). The segmental-level differences from both vowels and consonants between Taishanese and English were responsible for the reduced speech intelligibility.
Perception of conversational and clear speech syllables by native and non-native English-speaking listeners
Authors: Rogers Catherine L. , Voors Marissa , Luque Jenna
Published: May 2014

In a recent study later, but not earlier, learners of English as a second language produced a smaller clear-speech benefit than native English-speaking talkers for vowels produced in six /bVd/ syllables (Rogers et al., 2010, JASA 123, 410–423). The present study compares perception of the same syllables by native and non-native English-speaking listeners. Conversational and clear-speech productions of the target syllables, “bead, bid, bayed, bed, bad,” and “bod,” were selected from three monolingual English speakers who had produced a significant clear-speech benefit in Rogers et al. (2010). The syllables were then mixed with noise at several signal-to-noise ratios (SNRs). Perception of these stimuli by three groups of listeners will be examined: (1) monolingual native English speakers, (2) ‘early’ learners of English as a second language, with an age of immersion (AOI) of 12 or earlier, and (3) later learners of English as a second language, with an AOI of 15 or later. Analyses of results of the six-alternative forced-choice task will focus on comparisons across listener groups, for the following measures: (1) estimates of clear-speech benefit at approximately 50% correct; (2) performance at a common SNR; and (3) estimates of the slope of the psychometric function. [Work supported by NIH.]
Distance perception in the sound field reproduced by a linear loudspeaker array
Authors: Kang Dong-Soo , Choi Jung-Woo , Kim Yang-Hann
Published: May 2014

When a sound field from a virtual sound source is reproduced by a linear loudspeaker array, a listener in the sound field can perceive the distance of the virtual source, as well as its direction. It has been known that the perception of distance is affected by many acoustic parameters, such as the loudness change, direct-to-early reflection energy ratio, and interaural level difference (ILD). Among them, ILD is the dominant cue to perceive distance when the source is located near the lateral side of the listener [Brungart and Rabinowitz, J. Acoust. Soc. Am. 106(3), Sept. 1999]. Nevertheless, ILD of the reproduced sound field are not identical to that of the target sound field, because the loudspeaker array reproducing the sound field has many practical limitations such as spatial aliasing and truncation of array aperture. To identify these artifacts, especially for the virtual source in a close proximity to the listener, a head-scattering model is constructed using a simple rigid sphere. The ILDs at various head locations are then calculated and compared to those of the target sound field. From the observations on ILD change, a driving function is modified to reconstruct ILDs of the target sound field.
Broadband acoustic-source localization using passive sonar via multitask learning
Authors: Forero Pedro A. , Baxley Paul A.
Published: May 2014

Passive sonar is an attractive technology for underwater acoustic-source localization that enables the localization system to conceal its presence and does not perturb the maritime environment. Notwithstanding its appeal, passive-sonar-based localization is challenging due to the complexities of underwater acoustic propagation. Different from alternatives based on matched-field processing whose localization performance severely deteriorate when localizing multiple sources and when faced with model mismatch, this work casts the broadband underwater acoustic-source localization problem as a multitask learning (MTL) problem, thereby enabling robust and high-resolution localization. Here, each task refers to a sparse signal approximation problem over a single frequency. MTL provides an elegant framework for exchanging information across the individual regression problems and constructing an aggregate (across frequencies) source localization map. The localization problem is formulated as a stochastic least-squares optimization problem with a group sparsity constraint enforcing a common support across frequency maps. Efficient algorithms based on block coordinate descent are developed for solving the localization problem. Predictor screening rules are also developed to further reduce the computational complexity of the proposed method. Numerical tests on real data illustrate and compare the localization performance of the proposed algorithm to that of competitive alternatives.
Transient detection via acoustic particle velocity multi-mission sensor
Authors: Solomon Latasha , Sim Leng
Published: May 2014

In this research, we compare the direction of arrival (DOA) accuracy of a micro-electro-mechanical systems (MEMS) based acoustic particle velocity sensor developed by Microflown Technologies with that of a collocated, 1-m tetrahedral array. When deployed as an unattended sensor system, the Acoustic Multi-Mission Sensor (AMMS) greatly facilitates hardware set-up and periodic maintenance. An array of microphones is now replaced by a single sensor, saving in overall system cost, size, weight, and power usage. The single sensor has the capability to measure both the (scalar) sound pressure and the (vector) acoustic particle velocity, thus providing DOA estimates. This research will explore performance and determine limitation of the two sensors in complex environments as well as open fields for detection of both small arms fire (SAF) and rocket propelled grenades (RPGs).
Estimation algorithm coordinates source signal towed long antenna
Authors: Anikin Igor Y.
Published: May 2014

In some sonars is requirе the use of towed long antenna. By “large”long antenna is understood conventionally antenna directivity pattern width is less than some value, for example, less than 1°. Due to the large antenna length when towing a change in its form, as well as change of coordinates the source relative to antenna. For this reason, the source coordinates are determined with errors. The report discusses an algorithm for estimating the coordinates the source of towed long antenna. Algorithm consists in the separation of the antenna into several sections. Section length is chosen so that the antenna directivity pattern width of the section was 1°... 2°. Each section is formed by the fan of directivity patterns. The joint processing of signals from the output of the directivity patterns of the fan formed by sections of the antenna provides the coordinates of the source. Results of mathematical modeling error estimates of coordinates, offered algorithm are compared with the potential errors that follow from the Cramer-Rao inequality.
Improved modal dispersion estimation using vertical array beamforming
Authors: Vinciullo Valerie , Potty Gopu R. , Cockrell Kevin , Miller James H.
Published: May 2014

Geoacoustic inversions using modal dispersion data is a very robust technique to estimate properties of the shallow water sediments. Accurate estimation of the modal arrival times is required for improving the accuracy of the inversion. A time-frequency analysis of the single hydrophone data is typically used to extract modal arrival times. This study explores the possibility of incorporating the data from a vertical line array (VLA) to enhance the accuracy of arrival time estimation. The method relies on beam forming in horizontal wavenumber at each instant in time to produce a time-frequency-wavenumber diagram (movie) which will provide an extra dimension to help separate the modes. For a given time and horizontal wavenumber, the arrival time is unique since the group speed is uniquely determined by the frequency and horizontal wavenumber. So, even if the time and wavenumber resolution is not sufficient identify individual modes, the 3-D surface plot of arrival time versus frequency and wavenumber can be created. The shape of that surface can be compared to simulated surfaces for geoacoustic inversion, even if mode arrivals appear to overlap. This approach will be tested using synthetic data and the length and spacing requirements of the VLA will also be investigated. [Work supported by Office of Naval Research, code 322OA.]
Research on rotary spiral array applied in near-field acoustical holography
Authors: Lin-Song Chen
Published: May 2014

This paper presents a new method to apply a spiral array in nearfield acoustical holography (NAH). Usually, a NAH array needs much more microphones than beamforming array does. Superior to a uniform planar array or linear scanning array, this spiral array rotates to get more measuring data. Without any static referring microphone, a numerical method was suggested to estimate the phase difference measured at different time. Numerical simulations and a series experiment confirmed that this method is adequate for the sound below 450 Hz. It is especially useful for using a random planar array at NAH mode, while the beamforming mode can only cover the higher frequency band.
Tank acoustics, and sound source localization by plainfin midshipman fish (Porichthys notatus)
Authors: Zeddies David , Gray Michael D. , Rogers Peter H. , Fay Richard R. , Sisneros Joseph A.
Published: May 2014

A series of experiments was undertaken to investigate methods of sound source localization by fish. In these experiments, positive phonotaxic responses of gravid female plainfin midshipman fish (Porichthys notatus) to low-frequency, playback tones (80–90 Hz) were studied as they approached sound sources. The sound fields for simple (monopole) and relatively complex (dipole) sources within the behavioral arena were measured and characterized in terms of pressure and particle motion. Results indicate that female midshipman fish are able to locate sound sources in the near field using acoustic cues alone, and that they used the particle motion vectors to locate the source in both the monopole and dipole sound fields. The tank acoustics were modeled and compared to the measured pressure and particle motion sound fields. [This work was supported by the National Science Foundation.]
Real-time acoustic monitoring and source level estimates of walruses in the northeastern Chukchi Sea using particle velocity sensors
Authors: Mouy Xavier , Delarue Julien , Martin Bruce , Hannay David , Jay Chadwick , Fishbach Anthony
Published: May 2014

Particle motion sensors measure the vector component of the sound field. In underwater acoustics, they are used for studying the physics of the sound field, evaluating the potential effects of sound on fish, and defining the direction of arrival (DOA) of sound sources. Measuring the DOA in the vertical and horizontal plane allows two separate receivers to localize an acoustic source in three dimensions. In July 2013, we used two custom-built, real-time particle velocity acoustic recording systems to record and localize vocally active walruses in the water near groups hauled out on ice in the northeastern Chukchi Sea. The system was equipped with a three-axis dipole sensors and a calibrated omni-directional hydrophone. It was deployed at the water surface and transmitted data in real-time to a support skiff. The range between the recorders, support skiff, and calling animals was usually less than 200 m and typically within a few tens of meters, allowing for simultaneous visual observations. Calling walruses were localized using cross-fixes of acoustic bearings. Source levels were estimated by adding modeled frequency-dependent transmission losses to the received levels in each 1/3-octave-band obtained from the calibrated omni-directional hydrophone. Only calls with high signal-to-noise ratio were used in this analysis. The use of the particle velocity sensor allowed for the first source level measurements of walrus grunts and bell calls in the wild.
Underwater techniques to characterize the near scattered acoustic vector field
Authors: Barton Robert J. , Moss Geoffrey R. , Amaral Brian K. , Dossot Georges , Smith Kevin B.
Published: May 2014

In this study, we investigate the properties of the scattered acoustic vector fields generated by simple geometric objects, including the infinite rigid plate, disk, and sphere. Analytical solutions are derived from acoustic target strength scattering models in the near-field region. Of particular interest is the understanding of the characteristics of energy flow of the scattered acoustic vector field in the near- to far- field transition region. We utilize the time and space separable instantaneous active and reactive acoustic intensities to investigate the relative phase properties of the scattered field. Numerical results are presented for the near region scattered acoustic vector field of simple objects in both two and three dimensions. Previous in-air measurements are summarized, and an approach to taking water-borne measurements is offered.
Acoustic energy streamlines in inhomogeneous fluids
Authors: Godin Oleg A.
Published: May 2014

First introduced by Umov in 1873, wave energy streamlines offer an intuitive and informative description of energy flow much like conventional streamlines do for mass flow in fluid mechanics. Growing availability and increasing practical applications of acoustic vector sensors, such as sound-intensity meters, have led to a surge of interest to energy streamlines. In contrast to rays, which are essentially an asymptotic, short-wave concept, energy streamlines adequately represent arbitrary acoustic fields and reveal intricate and often unexpected details of the acoustic energy flow. Modern usages of the energy streamlines include studies of wave front dislocations, source localization, energy vortices in compressible fluids and elastic waveguides, and bounded beam diffraction. This paper will focus on applications of the energy streamlines to the description of reflection and refraction of acoustic waves at interfaces and to localization of low-frequency sound sources.
Observations of elliptical particle motion in shallow water and its dependence on source depth
Authors: Dall'Osto David R. , Dahl Peter H.
Published: May 2014

Acoustic particle motion that follows an elliptical path coincides with a non-zero curl of the time-averaged intensity. This vector property is also observed as curvature in intensity (energy-flux) streamlines. Measurements of the acoustic intensity field made in shallow water are presented, along with simulations of the intensity field, to demonstrate some interesting relations between acoustic intensity and elliptical particle motion. Specifically, the direction in which intensity streamlines bend (sign of the curl of intensity) corresponds to the polarization of acoustic particle motion. For a source located in water, the polarization of particle motion depends on the modes of the underwater waveguide excited at a particular source depth. By raising a source up through the water column, an abrupt change in the polarization of particle motion can occur. This effect is examined with vector sensor data collected during an experiment near Panama City, FL. For a source located in air, elliptical particle motion is most evident a few wavelengths below the sea-surface where the contribution of the lateral (evanescent) wave is significant. This effect is examined with a recording of aircraft noise on both sides of the air-water interface made near Oak Harbor, WA.
Research on the double vector hydrophones’ location for underwater low frequency source depth identification
Authors: Zhao Anbang , Song Xuejing , Zhou Bin , Bi Xuejie
Published: May 2014

The double vertically arranged vector hydrophones’ pressure and horizontal velocity cross spectrum in Pekeris waveguide is derived, and the sign distribution of its active component is analyzed. The sign distribution varies with the horizontal ranges and source depths regularly, the signs change in a certain depth and the depth is defined as critical depth. By locating the vector hydrophones properly, a critical depth which is independent of horizontal range can be obtained, and this characteristic can be used for discriminating the source depth. The method of forecasting the vector hydrophones’ locating depths according to the requirements of the critical depth is studied, and the forecast accuracy is validated by the simulation results. A reasonable set of the critical depth is conducive to discriminate the source depth accurately and effectively, which has extensive application prospects.
A tutorial on psychoacoustical approaches relevant to listening in rooms
Authors: Gallun Frederick J.
Published: May 2014

From the year of its founding, members of the Acoustical Society of America have been interested in the question of how the acoustical effects of real-world environments influence the ability of human beings to process sound (Knudsen, “The hearing of speech in auditoriums,” JASA 1(1), 1929). While interest in this topic has been constant, the specialization of those focused on architectural acoustics and those focused on psychological and physiological acoustics has increased. Today, it is easily observed that we are likely to use methods and terminology that may be quite unfamiliar to those discussing a very similar question just down the hall. This presentation will survey a few of the most influential psychoacoustical approaches to the question of how the detection and identification of stimuli differs depending on whether the task is done in a real (or simulated) room as opposed to over headphones or in an anechoic chamber. The goal will be to set the stage for some of the talks to come and to begin a discussion about methods, terminology, and results that will help turn the diverse backgrounds of the participants into a shared resource rather than a barrier to understanding.
Speech intelligibility in rooms: An integrated model for temporal smearing, spatial unmasking, and binaural squelch
Authors: Leclère Thibaud , Lavandier Mathieu , Culling John F.
Published: May 2014

Speech intelligibility predictors based on room characteristics only consider the effects of temporal smearing of speech by room reflections and masking by diffuse ambient noise. In binaural listening conditions, a listener is able to separate target speech from interferering sounds. Lavandier and Culling (2010) proposed a model which incorporates this ability and its susceptibility to reverberation, but it neglects the temporal smearing of speech, so that prediction only holds for near-field targets. An extension of this model is presented here which accounts for both speech transmission and spatial unmasking, as well as binaural squelch in reverberant environments. The parameters of this integrated model were tested systematically by comparing the model predictions with speech reception thresholds measured in three experiments from the literature. The results showed a good correspondence between model predictions and experimental data for each experiment. The proposed model provides a unified interpretation of speech transmission, spatial unmasking, and binaural squelch.
Reverberation and noise pose challenges to speech recognition by cochlear implant users
Authors: Neuman Arlene C.
Published: May 2014

The cochlear implant (CI) provides access to sound for a growing number of persons with hearing loss. Many CI users are quite successful in using the implant to understand speech in ideal listening conditions, but CI users also need to be able to communicate in noisy, reverberant environments. There is a growing body of research investigating how reverberation and noise affect speech recognition performance of children and adults who use cochlear implants. Findings from our own research and research from other groups will be reviewed and discussed.
Investigation of speech privacy in high-speed train cabins using a 1:10 scale model
Authors: Lim Hansol , Jang Hyung Suk , Jeon Jin Yong
Published: May 2014

In this study, a 1:10 scale model was used to evaluate the acoustical parameters and speech transmission indices in high-speed train cabins when the interior design factors are changed to improve speech privacy. The 1:10 scale model materials were selected by considering real measured target factors, such as reverberation time (RT) and speech level (Lp,A,s). The characteristics of the background noise in a high-speed train depend on the train’s speed; therefore, recordings of the background noise (LAeq) inside a train were considered in three situations: a stopped train, a train traveling at 100 km/h, and a train traveling at 300 km/h. The values of the STI were reproduced with the background noise levels at each speed using external array speakers with an equalizing filter in the scale model. The shapes and absorptions of chairs and interior surfaces were evaluated using scale modeling.
Laboratory experiments for speech intelligibility and speech privacy in passenger cars of high speed trains
Authors: Oh Sung Min , Hong Joo Young , Jeon Jin Yong
Published: May 2014

This study explores the speech privacy criteria in passenger cars of high-speed trains. In-situ measurements were performed in running trains to analyze the acoustical characteristics of interior noises in train cabins, and laboratory experiments were conducted to determine the most appropriate single-number quantity for the assessment of speech privacy. In the listening tests, the participants were asked to rate (1) speech intelligibility, (2) speech privacy, and (3) annoyance with varying background noises and signal to noise ratio (SNR). From the results of the listening tests, the effects of background noise levels and SNR on the speech privacy and annoyance were examined and the optimum STI and background noise levels in the passenger car concerning both speech privacy and annoyance were derived.
Use of k-means clustering analysis to select representative head related transfer functions for use in subjective studies
Authors: Neal Matthew , Vigeant Michelle C.
Published: May 2014

A head related transfer function (HRTF) must be applied when creating auralizations; however, the HRTFs of individual subjects are not typically known in advance. Often, an overall ‘average’ HRTF is used instead. The purpose of this study was to develop a listening test to identify a ‘matched’ (best) and ‘unmatched’ (worst) HRTF for specific subjects, which could be applied to customize auralizations for individual participants. The method of k-means clustering was used to identify eight representative HRTFs from the CIPIC database. HRTFs from 45 subjects’ left and right ears in four directions were clustered, which resulted in 56 cluster centers (possible representative HRTFs). A comparative analysis was conducted to determine an appropriate set of HRTFs. These HRTFs were then convolved with pink noise bursts at 00 elevation and various azimuths to sound like the bursts were rotating around a subject’s head. A paired comparison test was used where listeners selected the ‘most natural’ sounding HRTF signal. ‘Most natural’ was described as coming from the correct directions and located outside the head. The results from the clustering analysis and listening test will be presented, along with a subjective study that incorporated the HRTF listening test. [Work was supported by NSF Grant 1302741.]
Improving acoustic time-of-arrival location estimates by correcting for temperature drift in time base oscillators
Authors: Cheyne Harold A. , Marchetto Peter M. , Mack Raymond C. , Salisbury Daniel P. , Morano Janelle L.
Published: May 2014

Using multiple acoustic sensors in an array for estimating sound source location relies on time synchrony among the devices. When independent time synchrony methods—such as GPS time stamps—are unavailable, the precision of the time base in individual sensors becomes one of the main sources of error in synchrony, and consequently increases the uncertainty of location estimates. Quartz crystal oscillators, on which many acoustic sensors base sampling rate timing, have a vibration frequency that varies with temperature f(T). Each oscillator exhibits a different frequency-temperature relationship, leading to sensor-dependent sample rate drift. Our Marine Autonomous Recording Units (MARUs) use such oscillators for their sample rate timing, and they experience variations in temperature of at least 20°C between preparation in air and deployment underwater, leading to sample rate drift over their deployments. By characterizing each MARU’s oscillator f(T) function, and measuring the temperature of the MARU during the deployment, we developed a post-processing method of reducing the sample rate drift. When applied to acoustic data from an array of MARUs, this post-processing method resulted in a statistically significant decrease of the mean sample rate drift by a factor of two, and subsequent lower errors in acoustically derived location estimates.
Acoustic scene metrics for spatial planning
Authors: Vigness-Raposa Kathleen J. , Frankel Adam S. , Giard Jennifer , Hunter Kenneth T. , Ellison William T.
Published: May 2014

Potential effects of anthropogenic underwater sounds on marine mammals are usually assessed on the basis of exposure to one sound source. Recently published research modeling underwater noise exposure and assessing its impact on marine life has extended the typical single source/single species absolute received level approach to defining exposure in a variety of ways including: relative levels of exposure, such as loudness, signal to noise ratio, and sensation level; metrics for evaluating chronic elevation in background noise; cumulative exposure to multiple and dissimilar sound sources, as well as the potential for animals to selectively avoid a particular source and other behavioral changes. New approaches to managing the overall acoustic scene that account for these issues requires a more holistic and multi-dimensional approach that addresses the relationships among the noise environment, animal hearing and behavior, and anthropogenic sound sources. We present a layered acoustic scene concept that considers each facet of the extended problem. Our exemplar is a seismic survey in the Gulf of Mexico with layers for ambient oceanographic and meteorological noise, shipping, and distant anthropogenic sources in which the exposure is filtered by the animal’s hearing filter, sensation level, and nominal loudness of the signal.
Quantifying the ocean soundscape at a very busy southern California location
Authors: Joseph John E. , Margolina Tetyana
Published: May 2014

The underwater noise environment in the Southern California Bight is highly variable due to the presence of both episodic and persistent contributors to the soundscape. Short-term events have potential for inducing abrupt behavioral responses in marine life while long-term exposure may have chronic influences or cause more subtle responses. Here we identify and quantify various sources of sound over a wide frequency band using a passive acoustic receiver deployed at 30-mi Bank from December 2012 through March 2013. The site is in the eastern portion of the Navy’s training range complex and is in close proximity to very active shipping routes. The region has diverse marine habitats and is known for frequent seismic activity. Acoustic data were scanned for anthropogenic, biologic and other natural noise sources up to 100 kHz. In addition, ancillary databases and data sets were used to verify, supplement and interpret results. Acoustic propagation models were used to explain ship-induced noise patterns. Results indicate that long-term trends in soundscapes over regional-scale areas can be accurately estimated using a combination of tuned acoustic modeling and recurrent in-situ data for validation. [Project funded by US Navy.]
Sound-based automatic neotropical sciaenid fishes identification: Cynoscion jamaicensis
Authors: Ruiz-Blais Sebastian , Camacho Arturo , Rivera-Chavarria Mario R.
Published: May 2014

Automatic software for sciaenid sound emissions identification are scarce. We present a method to automatically identify sound emissions produced by the sciaenid Cynoscion jamaicensis. The emissions of C. jamaicensis typically have a 24 Hz pulse repetition rate and a quasi-harmonic pattern in their spectra with a pitched quality in its sound. The proposed method is an adaptation of a previous method proposed to detect sounds of Cynoscion squamipinnis in recordings. It features long-term partial loudness, pulse repetition rate, pitch strength, and timbre statistics. The satisfactory results of 0.9 in the F-measure show that the method generalizes well over species, considering the different characteristics of C. jamaicensis and C. squamipinnis. Future research is required to test the method with other species recordings, in order to further evaluate its robustness.
Examining the impact of the ocean environment on cetacean classification using theocean acoustics and seismic exploration synthesis (OASES) propagation model
Authors: Binder Carolyn M. , Hines Paul C.
Published: May 2014

Passive acoustic monitoring (PAM) is now in wide use to study cetaceans in their natural habitats. Since cetaceans can be found in all ocean basins, their habitats cover diverse underwater environments. Properties of the ocean environment such as the sound speed profile, bathymetry, and sediment properties can be markedly different between these diverse environments. This leads to differences in how a cetacean vocalization is distorted by propagation effects and may impact the accuracy of PAM systems. To develop an automatic PAM system capable of operating effectively under numerous environmental conditions one must understand how propagation conditions affect these systems. Previous effort using a relatively limited data set has shown that a prototype aural classifier developed at Defence R&D Canada can be used to reduce false alarm rates and successfully discriminate cetacean vocalizations from several species. The aural classifier achieves accurate results by using perceptual signal features that model the features employed by the human auditory system. The current work uses the OASES pulse propagation model to examine the robustness of the classifier under various environmental conditions; preliminary results will be presented from cetacean vocalizations that were transmitted over several ranges through environments modeled using conditions measured during experimental trials.
Acoustic detection, localization, and tracking of vocalizing humpback whales on the U.S. Navy's Pacific Missile Range Facility
Authors: Helble Tyler A.
Published: May 2014

A subset of the 41 deep water broadband hydrophones on the U.S. Navy's Pacific Missile Range Facility (PMRF) to the northwest of Kauai, Hawaii was used to acoustically detect, localize, and track vocalizing humpback whales as they transited through this offshore range. The focus study area covers 960 square kilometers of water (water depths greater than 300 m and more than 20 km offshore). Because multiple animals vocalize simultaneously, novel techniques were developed for performing call association in order to localize and track individual animals. Several dozen whale track lines can be estimated over varying seasons and years from the hundreds of thousands of recorded vocalizations. An acoustic model was used to estimate the transmission loss between the animal and PMRF hydrophones so that source levels could be accurately estimated. Evidence suggests a Lombard effect: the average source level of humpback vocalizations changes with changes in background noise level. Additionally, song bout duration, cue (call) rates, swim speeds, and movement patterns of singing humpback whales can be readily extracted from the track estimates. [This work was supported by Commander U.S. Pacific Fleet, the Office of Naval Research, and Living Marine Resources.]
Variations of soundscape in a shallow water marine environment for the Chinese white dolphin
Authors: Guan Shane , Lin Tzu-Hao , Chou Lien-Siang , Vignola Joseph F.
Published: May 2014

For acoustically oriented animals, sound field can either provide or mask critical information for their well-being and survival. In addition, understanding the variations of the soundscape in the Chinese white dolphin habitat is important to monitoring the relationship between human activities, calling fish, and dolphins, thus assist in coastal conservation and management. Here, we examined the soundscape of a critically endangered Chinese white dolphin population in two shallow water areas next to western coast of Taiwan. Two recording stations were established at Yunlin, which is close to an industrial harbor, and Waisanding, which is nearby a fishing village, in summer 2012. Site specific analyses were performed on variations of the temporal and spectral acoustic characteristics for both locations. The results show different soundscapes for the two sites from different recurring human activities. At Yunlin, high acoustic energy was usually dominated by cargo ships producing noise below 1 kHz. At Waisanding, much higher frequency noise, up to 16 kHz produced by passing fishing boats were detected. In addition, a diurnal cycle of the acoustic field between 1200 and 2600 Hz was observed. It is established that this sound was produced by fish chorus that were observed in both locations.
Anthropogenic noise has a knock-on effect on the behavior of a territorial species
Authors: McLaughlin Kirsty E. , Kunc Hansjoerg P.
Published: May 2014

Noise pollution has been shown to induce overt behavioral changes such as avoidance of a noise source and changes to communication behavior. Few studies however have focused on the more subtle behaviors within an individual’s repertoire such as foraging and territoriality. Many species are territorial making it unlikely they will leave a noisy area. The impact of noise on essential behaviors of such species must be examined. It has been suggested that a noise induced increase in sheltering behavior will decrease time available for other activities. To test for this potential knock-on effect, we exposed a territorial fish to noise of differing sound pressure levels (SPL). We found that exposure to noise increased sheltering behavior and decreased foraging activity. However, we found that these behavioral responses did not increase with SPL. Furthermore we demonstrate, for the first time experimentally, that noise has a negative knock-on effect on behavior as a noise induced increase in sheltering caused a decrease in foraging activity. This novel finding highlights the importance of examining less overt behavioral changes caused by noise, especially in those species unlikely to avoid a noisy area, and suggests the impacts of noise on animals may be greater than previously predicted.
Investigation of effects of ultrasound on dermal wound healing in diabetic mice
Authors: Hocking Denise C. , Raeman Carol H. , Dalecki Diane
Published: May 2014

Chronic wounds, including diabetic, leg, and pressure ulcers, impose a significant health care burden worldwide. Currently, chronic wound therapy is primarily supportive. Ultrasound therapy is used clinically to promote bone healing and some evidence indicates that ultrasound can enhance soft tissue repair. Here, we investigated effects of ultrasound on dermal wound healing in a murine model of chronic wounds. An ultrasound exposure system and protocol were developed to provide daily ultrasound exposures to full-thickness, excisional wounds in genetically diabetic mice. Punch biopsy wounds were made on the dorsal skin and covered with acoustically transparent dressing. Mice were exposed to 1-MHz pulsed ultrasound (2 ms pulse, 100 Hz PRF, 0–0.4 MPa) for a duration of 8 min per day. Mice were exposed on 10 days over a 2-week period. No significant differences in the rate of re-epithelialization were observed in response to ultrasound exposure compared to sham-exposed controls. However, two weeks after injury, a statistically significant increase in granulation tissue thickness at the wound center was observed in mice exposed to 0.4 MPa (389 + /  85 μm) compared to sham exposures (105 + /Ő 50 μm). Additionally, histological sections showed increased collagen deposition in wounds exposed to 0.4 MPa compared to shams.
Temperature effects on the dynamics of contrast enhancing microbubbles
Authors: Meral Faik C.
Published: May 2014

Micron-sized, gas encapsulated bubbles are used as ultrasound contrast enhancing agents to improve diagnostic image quality. These microbubbles, which are vascular agents, undergo linear and non-linear oscillations when excited. It is this non-linear response of microbubbles, that helps to distinguish between signals from the tissue -mostly linear-, and signals from the bubbles,nonlinear, which represents vasculature. This opens up to numerous clinical applications such as echocardiography, focal lesion identification, perfusion imaging, etc. Characterization studies of microbubbles gained importance as the possible clinical applications increase. One aspect that these studies focused on is the temperature dependence of the microbubble dynamics. However, these studies were mostly comparing bubble dynamics at room temperature to their dynamics at the physiological temperatures. This study is focused on the changes in the bubble characteristics as a function of temperature. More specifically microbubble attenuation and scattering is measured as a function of temperature and time. Additionally, estimating the temperature changes from the changes in the bubble dynamics is considered as an inverse problem.
Response to ultrasound of two types of lipid-coated microbubbles observed with a high-speed optical camera
Authors: van Rooij Tom , Luan Ying , Renaud Guillaume , van der Steen Antonius F. W. , de Jong Nico , Kooiman Klazina
Published: May 2014

Microbubbles (MBs) can be coated with different lipids, but exact influences on acoustical responses remain unclear. The distribution of lipids in the coating of homemade MBs is heterogeneous for DSPC and homogeneous for DPPC-based MBs, as observed with 4Pi confocal microscopy. In this study, we investigated whether DSPC and DPPC MBs show a different vibrational response to ultrasound. MBs composed of main lipid DSPC or DPPC (2 C-atoms less) with a C4F10 gas core, were made by sonication. Microbubble spectroscopy was performed by exciting single MBs with 10-cycle sine wave bursts having a frequency from 1 to 4 MHz and a peak negative pressure of 10, 20, and 50 kPa. The vibrational response to ultrasound was recorded with the Brandaris 128 high-speed camera at 15 Mfps. Larger acoustically induced deflation was observed for DPPC MBs. For a given resting diameter, the resonance frequency was higher for DSPC, resulting in higher shell elasticity of 0.26 N/m as compared to 0.06 N/m for DPPC MBs. Shell viscosity was similar (~10-8 kg/s) for both MB types. Non-linear behavior was characterized by the response at the subharmonic and second harmonic frequencies. More DPPC (71%) than DSPC MBs (27%) showed subharmonic response, while the behavior at the second harmonic frequency was comparable. The different acoustic responses of DSPC and DPPC MBs are likely due to the choice of the main lipid and the corresponding spatial distribution in the MB coating.
Numerical simulations of ultrasound-lung interaction
Authors: Patterson Brandon , Miller Douglas L. , Dowling David R. , Johnsen Eric
Published: May 2014

Lung hemorrhage (LH) remains the only bioeffect of non-contrast, diagnostic ultrasound (DUS) proven to occur in mammals. While DUS for lung imaging is routine in critical care situations, a fundamental understanding of DUS-induced LH remains lacking. The objective of this study is to numerically simulate DUS-lung interaction to identify potential damage mechanisms, with an emphasis on shear. Experimentally relevant ultrasound waveforms of different frequencies and amplitudes propagate in tissue (modeled as water) and interact with the lung (modeled as air). Different length scales ranging from single capillaries to lung surface sizes are investigated. For the simulations, a high-order accurate discontinuity-capturing scheme solves the two-dimensional, compressible Navier-Stokes equations to obtain velocities, pressures, stresses and interface displacements in the entire domain. In agreement with theoretical acoustic approximations, small interface displacements are observed. At the lung surface, shear stresses indicative of high strains rates develop and are shown to increase nonlinearly with decreasing ratio of interface curvature to ultrasonic wavelength.
Green's function-based simulations of shear waves generated by acoustic radiation force in elastic and viscoelastic soft tissue models
Authors: Yang Yiqun , Urban Matthew W. , McGough Robert J.
Published: May 2014

The Green's function approach describes propagating shear waves generated by an acoustic radiation force in elastic and viscoelastic soft tissue. Calculations with the Green's function approach are evaluated in elastic and viscoelastic soft tissue models for a line source and for a simulated focused beam. The results for the line source input are evaluated at 200 time samples in a 101 by 101 point grid that is perpendicular to the line source. For a shear wave speed of 1.4832 m/s and a compressional wave speed of 1500 m/s, shear wave simulations for a line source input in elastic and viscoelastic soft tissue models are completed in 431 and 2487 s with Matlab scripts, respectively, where the shear viscosity is 0.1 Pa.s in the viscoelastic model. Simulations are evaluated at a single point for an acoustic radiation force generated by a 128 element linear array operating at 4.09 MHz, and these simulations require 228 s and 1327 s for elastic and viscoelastic soft tissue models, respectively. The results show that these are effective models for simulating shear wave propagation in soft tissue, and plans to accelerate these simulations will also be discussed. [Supported in part by NIH Grants R01 EB012079 and R01 DK092255.]