bluuebunny/crossref_metadata_2025 huggingface dataset:
Molecular subtyping of breast cancer in vitro using high-frequency ultrasound
Authors: Stiles Janeese E. , Thompson Laurel A. , Marvel Mandy H. , Sugiyama Janice E. , Doyle Timothy E.
Published: November 2013

The molecular subtypes of breast cancer correlate more strongly to prognosis, treatment response, and local recurrence than the traditional classifications based on histopathology. The ability to determine the subtype of breast tumors during surgery or biopsy in real time would provide physicians with new diagnostic capabilities to screen suspicious lesions, to perform high-precision surgery on malignant and premalignant lesions, and to personalize treatment for patients. This work studied the potential of using the molecular subtypes as natural biomarkers for characterizing breast cancer with high-frequency ultrasound (10–100 MHz). We hypothesized that high-frequency ultrasound would be able to detect variations in cell biomechanical properties due to mutations found in aggressive subtypes (e.g., basal-like and Her2 +). These mutations alter the expression levels of proteins that regulate the actin cytoskeleton, thereby modifying the biomechanical and thus ultrasonic properties of the cells. Pulse-echo measurements were acquired in vitro from breast cancer cell lines with different subtypes. The results showed that each cell line produced a unique ultrasonic spectral signature. One of the cell lines additionally exhibited changes over time, possibly due to dedifferentiation. Correlation of the results to other cell characterization methods will also be presented. [This work was supported by Utah Valley University.]
Measurements of sound absorption of living grass
Authors: Good Chelsea E. , Glean Aldo J. , Vignola Joseph F. , Judge John A. , Ryan Teresa J. , Bull Nicole B. , Turo Diego
Published: November 2013

This work presents measurements of acoustic absorption coefficients of sod samples with grass blades of different length. These measurements were made with a vertical acoustic impedance tube over a 200–1600 Hz frequency band. The acoustic measurements will be compared to values calculated using an equivalent fluid model. Sod is a coarse aggregate material such that the observed absorption will have components resulting from the different constituent elements. A layer of granular material with known acoustic properties is placed at the bottom of each sample to account for the acoustic absorption of soil. This work considers the sod as a two-component system: foliage and substrate (soil and roots together). The absorption effects due to each component were isolated by making measurements before and after shearing the mature foliage near the soil surface. We show the effects of foliage length on acoustic absorption. Measurements of sound absorption of living grass
A modal architecture for artificial reverberation
Authors: Abel Jonathan S. , Coffin Sean , Spratt Kyle S.
Published: November 2013

The method of analyzing an acoustic space by way of modal decomposition is well established. In this work, a computational structure employing modal decomposition is introduced for synthesizing artificial reverberation, implementing the modes using a collection of resonant filters, each driven by the source signal and summed in a parallel structure. With filter resonance frequencies and dampings tuned to the modal frequencies and decay times of the space, and filter gains set according to the source and listener positions, any number of acoustic spaces and resonant objects may be simulated. While convolutional reverberators provide accurate models but are inflexible and computationally expensive, and delay network structures provide only approximate models but are interactive and computationally efficient, the modal structure presented in this work provides explicit, interactive control over the parameters of each mode, allowing accurate modeling of acoustic spaces, movement within them and morphing among them. Issues of sufficient modal density, computational efficiency and memory use are discussed. Finally, models of measured and analytically derived reverberant systems are presented, including a medium-sized acoustic room and an electro-mechanical spring reverberator.
Real-time finite difference-based sound synthesis using graphics processors
Authors: Sosnick-Perez Marc , Hsu William
Published: November 2013

Finite difference methods can be used to model the vibrations of plates and membranes; the output of these numerical simulations can then be used to generate realistic and dynamic sounds. To create interactive, playable software instruments with finite difference methods, we need to be able run large simulations in real-time. Real-time finite difference-based simulations of large models are typically too compute-intensive to run on CPUs. The ubiquity of graphics processors (GPUs) today make them obvious choices for speeding up such applications. We have implemented finite difference simulations that run in real-time on GPUs. We will describe how we address the problems that arise from interactions between real-time audio constraints and GPU architecture and performance characteristics, and demonstrate the current version of FDS, our Finite Difference Synthesizer.
Noise exposure in the general audience of a Formula 1 race
Authors: Dolder Craig N. , Suits Joelle I. , Wilson Preston S.
Published: November 2013

Formula 1 cars have a reputation for being among the loudest race cars. As such, noise exposure should be a major concern for not only drivers, crew and staff, but also audience members. Calibrated acoustic measurements were taken at multiple general admission areas at a Formula 1 race. Analysis of these measurements show that the exposure exceeded multiple standards for daily noise exposure limits within a fraction of the race. This presentation predicts the total noise exposure experienced at different track positions and what noise reduction rating would be required in order to reduce the exposure to safe levels. [This work was supported by Brüel & Kjær.]
Multiple methods for calculating ultrasonic attenuation in liquids from non-invasive swept frequency experiments
Authors: Chaudhuri Anirban , Sinha Dipen N.
Published: November 2013

The swept frequency acoustic interferometry (SFAI) technique determines multiple acoustic properties of fluids in a single broadband frequency sweep measurement in a noninvasive manner. The technique employs two ultrasonic transducers on the outside of a test cell containing the liquid, one to transmit a swept-frequency signal and the other to receive the transmitted signal. Several different methods to extract frequency-dependent ultrasonic attenuation in liquids from the broadband frequency response (resonance spectrum) of the composite test cell will be described in this paper. These approaches take advantage of the characteristics of both the frequency response and the time response (derived from the Fourier transform) of the experimental data. These methods were first verified with simulated SFAI data generated using a 1-D multi-layer transmission model; a brief description of the model is presented. Attenuation values were then calculated for different fluids (deionized water, acetone, Fluorinert, 10W-30 motor oil, and crude oil) from experimental swept frequency data obtained using a specially designed laboratory test cell. The attenuation values computed using the different methods are consistent with each other, as expected. However, based on the quality of the experimental data, certain methods may be more appropriate in a given measurement condition.
System for automatic personalization of head-related transfer functions based on computer vision, photo-anthropometry, and inference from a database
Authors: Torres Gallegos Edgar A. , Orduña-Bustamante Felipe , Arámbula-Cosío Fernando
Published: November 2013

A software system and method for automatic personalization of head related transfer functions (HRTF) is presented. The system pursues the objective of personalizing HRTF using the anthropometry of the subject, as proposed originally by [Zotkin et al. WASPAA 2003, 157–160], which in this work, is measured automatically from a set of photographs of the subject. The system operates in three stages. First, a computer vision algorithm, known as active shape models, is used over the portraits to recognize and adjust geometric form profiles of the ears, head, and torso of the subject. Then, anthropometry is performed by measurement of pixel distances between specific points in the model, and then converted into metric units. Finally, HRTF are estimated from the anthropometry using a choice of three methods, whose performance is compared: (1) HRTF selection of the best anthropometric match in the CIPIC database, (2) HRTF synthesis by multiple linear regression and principal component analysis, and (3) HRTF synthesis using an artificial neural network. Results are analyzed, concluding that automatic personalization of HRTF is attainable automatically from the subject portraits, using computer vision and inference from a database. Further analysis, however, reveals the need for more complete HRTF and anthropometric databases.
Spatial separation decreases psychoacoustic roughness of high-frequency tones
Authors: Villegas Julián , Martens William L. , Cohen Michael , Wilson Ian
Published: November 2013

Perceived roughness reports were collected for pairings of sinusoidal tones presented either over loudspeakers or headphones such that the sounds were collocated or spatially separated 90 degrees in front of the listener (+ /− 45 degrees). In the loudspeaker experiment, pairs of sinusoids were centered at 0.3, 1.0, and 3.3 kHz, and separated by half a critical band. In the headphone experiment, the pairs of sinusoids were centered at 0.5, 1.0, and 2.0 kHz, and separated by a semitone. Although not all listeners’ reports showed the influence of spatial separation as clearly as others, analysis indicates that listeners generally found spatially separated tone combinations less rough when the frequencies of those tones were centered at 2.0 kHz or higher. This trend was also observed in a follow-up study with 20-component complex tones at fundamental frequencies of C2, C3, A4, and C4 (131, 262, 440, and 523 Hz, respectively) presented via headphones. These results suggest that spatial separation decreases perceived roughness, especially for tones with frequencies higher than the threshold at which interaural time differences rival interaural level differences for sound localization (approximately 2.3 kHz) and that the current roughness models need to be reviewed to include binaural effects.
The effect of firefighter personal protective equipment on auditory thresholds
Authors: Suits Joelle I. , Champlin Craig A. , Wilson Preston S. , Ezekoye Ofodike A.
Published: November 2013

Communication on a fire scene is essential to the safety of firefighters. Not only to be able to hear and understand radio chatter, but also alarm signals used on the fireground. One such alarm is the Personal Alert Safety System (PASS) device. This device is used to help locate a downed firefighter. One part of this complex problem is the effect of the protective equipment (helmet, eye protection, hood, coat) on hearing. Previous findings have shown the effect of this protective equipment on head related transfer functions using a KEMAR. [Suits et al. (2013, June). Paper presented at the International Congress on Acoustics, Montreal, Canada] The physical acoustic measurements showed a change in the signal that would reach the tympanic membrane. To relate the findings of the physical measurements to human reactions, the change in auditory threshold caused by wearing the personal protective equipment was measured. The changes seen in the physical acoustics measurements caused the auditory threshold of the subjects to increase at higher frequencies. The measured increases at 3000 Hz, 4000 Hz, and with an example PASS signal were between 5 and 10 dB. [Work supported by U.S. Department of Homeland Security Assistance to Firefighters Grants Program.]
Perceptual contribution of vowel sub-segments to Mandarin tone identification
Authors: Chen Fei , Wong Lena L. N. , Wong Eva Y. W.
Published: November 2013

Recent noise-replacement studies showed that (1) vowels carried more intelligibility information in Mandarin sentence recognition, and (2) a little vowel onset portion could significantly increase the intelligibility when it was added to the consonant-only Mandarin sentences. This study further evaluated the perceptual contribution of vowel sub-segments to Mandarin tone identification. The original duration-normalized vowels (FULL) were modified to produce two types of stimulus, i.e., (1) Left-only [LO (p)], which preserved p = 10% to 50% of the initial vowel portion, and replaced the rest vowel portion with speech-shaped noise (SSN), and (2) center-only [CO (p)], which preserved p = 15% to 60% of the center vowel portion, and replaced the rest initial and final vowel portions with SSN. Tone identification scores were collected from 20 normal-hearing native-Mandarin listeners. Results in the present study showed that (1) Mandarin tone perception at the LO (10%) condition was slightly higher than the chance level (i.e., 25%); (2) tone identification at the CO (60%) condition was not significantly different with that at the FULL condition. These findings suggest that vowel onset portion provides information redundant to vowel centers for Mandarin tone identification, and vowel centers contain sufficient information for reliable Mandarin tone identification.
The role of syntax in maintaining the integrity of streams of speech
Authors: Kidd Gerald , Mason Christine , Best Virginia
Published: November 2013

This study examined the ability of listeners to utilize syntactic structure to extract a target stream of speech from among competing sounds. Target talkers were identified by voice or location, which was held constant throughout an utterance, and were constructed to have either correct syntax or random word order. Both voice and location provided reliable cues for identifying target speech even when other features varied unpredictably. The target sentences were masked either by predominantly energetic maskers (noise) or by highly uncertain informational maskers (similar speech in random word order). When the maskers were noise bursts, target sentence syntax had relatively minor effects on identification performance. However, when the maskers were other utterances, target sentence syntax resulted in significantly better speech identification performance. In addition, conformance to correct syntax alone was sufficient to accurately identify the target speech. The results were interpreted as support for the idea that the predictability of the elements comprising streams of speech, as manifested by syntactic structure, is an important factor in binding words together into coherent streams. Furthermore, these findings suggest that predictability is particularly important for maintaining the coherence of an auditory stream over time under conditions high in informational masking.
Simultaneous recording of brain responses indicating sensation and perception of changes in interaural phase differences
Authors: Ross Bernhard , Fujioka Takako
Published: November 2013

Changing the interaural phase difference (IPD) between binaurally presented tones induces the sensation of a change of the sound source in space and elicits auditory brain responses specific for sound localization. We recorded neuromagnetic responses to IPD changes in young, middle-aged, and older listeners at various tonal frequencies. Young listeners showed brain responses below 1500 Hz according to the behavioral findings of using IPD for sound localization at low frequencies only. The upper limit for IPD detection decreased with age, and older listeners (mean age of 71 years) could make use of IPD changes only for tonal sounds below 750 Hz. The stimuli were amplitude modulated at 40 Hz and elicited synchronized brain activity at the rhythm of the amplitude modulation. Thus, 40-Hz brain activity was recorded simultaneously with the IPD change responses. Although the amplitude modulation as continuous and specifically did not change the interaural phase relation, the 40-Hz brain response was reset at the IPD change. We interpret the 40-Hz brain responses as related to sensory binding for perception. Each change in the auditory environment requires a reset and reconfiguration of the binding network, which can be observed in the reset of 40-Hz brain oscillations. Recording simultaneously brain responses to sensation and perception of IPD changes gives insight into the temporal dynamics of binaural auditory processing.
Effects of emotional prosody on word recognition
Authors: Kim Seung Kyung , Sumner Meghan
Published: November 2013

Phonetic variation in speech informs listeners not only about the linguistic message but also about talkers (e.g., gender, age, and emotion). In most episodic theories of speech perception, this indexical variation is accommodated via an acoustically-detailed exemplar lexicon. This view assumes lexical and indexical information are coupled, but speakers use acoustic patterns productively to convey information independent of the words they utter. We investigated the effects of emotional prosody on word recognition to test whether indexical information affects word recognition independent of lexical information. First, we compared the recognition of emotion word targets (UPSET) preceded by semantically unrelated words spoken with emotionally related or unrelated prosody (pineapple[AngryVoice] or pineapple[NeutralVoice]). Second, we investigated the effects of emotional prosody on semantically-related target words (pineapple[AngryVoice] or pineapple[NeutralVoice]—FRUIT). Recognition of both emotionally related and semantically related targets was facilitated by prime words spoken with angry prosody. These data suggest that indexical variation in speech influences word recognition beyond acoustically-detailed lexical representations. We suggest listeners simultaneously process acoustic variation for indexical and lexical meaning and argue that emotional prosody activates emotion features and categories, independent of lexical access.
Using tactile aids to provide low frequency information for cochlear implant users
Authors: Wang Shuai , Zhong Xuan , Dorman Michael F. , Yost William A. , Liss Julie M.
Published: November 2013

Cochlear implant (CI) users have shown benefit from residual low-frequency hearing in the contra-lateral ear (Dorman and Gifford, 2010). One source of this benefit is the enhancement of cues important for identifying word boundaries (Spitzer et al., 2009). However, there are a large number of CI users who do not have residual hearing, but who could presumably benefit from cues available in low-frequency information. Because the frequency sensitivity of human haptic sensation is similar to that of human acoustic hearing in low frequencies, we examined the ability of tactile aids to convey low-frequency cues. Using experimental phrases designed to have low inter-word predictability, and balanced for syllabic stress (trochaic/iambic), 5 CI users and 10 normal hearing participants (simulation) provided transcriptions that were scored for percent words-correct and for errors in word segmentation (lexical boundary errors, LBE). A 350 Hz sinusoid carrier modulated with overall envelope of corresponding acoustic signal drove two bone-anchored hearing aids (BAHA), which participants held while listening. Results showed a small but significant improvement on percent words correct with tactile aid, and fewer word segmentation errors. These findings support the benefit of tactile information in the perceptual task of lexical segmentation.
The effect of aging on auditory processing: Temporal resolution and informational masking
Authors: So Won , Jin Su-Hyun
Published: November 2013

This study examined age-related changes in temporal resolution and speech perception in noise. Older listeners tend to exhibit more difficulty listening in noise, especially, understanding speech in complex noise, such as temporally modulating noise. The current study examined younger and older listeners for their understanding of speech in spectrally remote modulating noise. When the spectrum of noise is distant from that of speech, the effect of energetic masking would be minimized, leading us to measure the effect of informational masking on speech perception. We hypothesized that older listeners may show a significant amount of informational masking even when the noise spectrum is distant from the speech spectrum due to greater central interference of the noise compared to younger listeners. We also measured pure tone glide detection in steady and gated noise (Nelson etal., 2011). When the pure tone frequency changes from low to high (or high to low), which is similar to spectral change in speech, older listeners might have more difficulty detecting glides in modulating noise than younger listeners because they would not be able to detect spectral changes available in the brief dips in the modulating noise.
Effects of musical rhythm training on infants’ neural processing of temporal information in music and speech
Authors: Zhao Tian , Kuhl Patricia K.
Published: November 2013

Investigations of musical training provide a way to study neural plasticity within the domain of music, as well as to study transfer effects to other domains (speech). Previous research has reported anatomical and functional differences between musically trained and non-trained individuals. However, these studies have not addressed several issues, including (1) nature vs nurture, (2) timing of musical training, and (3) the temporal aspect (e.g., rhythm) of musical training rather than the frequency aspect (e.g., pitch). The current study aims to examine of the causal effect of musical training on the sensitivity to temporal information in both music and speech sounds in infancy. In the study, 9-month-old infants were randomly assigned to a 12-session musical training condition vs a control condition (mirroring the design of Kuhl et al., 2003). During training, infants were exposed to uncommon metrical structure in music through social, multimodal, and structured activities while infants played freely in the control condition. After training, infants’ sensitivities to occasional violations in temporal structure were examined, both in music and speech. A traditional oddball paradigm was used and infants’ neural activities were recorded by MEG. Data from pilot participants will be discussed. [Research supported by I-LABS’ Developing Mind Project.]
Assessing whether loud speech affects vowel formant values in toddlers
Authors: Koenig Laura L. , Preston Jonathan
Published: November 2013

Extensive token-to-token variability is a widely-noted characteristic of child speech. This variability likely arises from several sources. In a recent analysis of vowel formants in the speech of toddlers, we observed that some children produced extreme ranges of F1 for the same target vowel, and that some high values of F1 were associated with a loud voice. Here, we undertake a systematic analysis of vowel formants as a function of perceived loud voice. Data were obtained from children 2–3 years of age producing many repetitions of the words “baby,” “ball,” “boy,” “bubble,” “moo,” and “pooh.” Since mouth-to-microphone distance varied, an acoustic measure of loudness was not possible. However, speaking level can affect voice quality and possibly other production features, and might be reliably perceptible nevertheless. All word productions suitable for acoustic analysis will be auditorily assessed by naïve listeners as having “regular voice” or “loud voice.” We will then determine whether productions judged as loud vary systematically in their formant frequencies. If so, it would suggest that researchers studying young child speech should attempt to limit extreme variations in vocal loudness, particularly if they are interested in acoustic measures of variability.
Modeling the perception of speaker age and sex in children's voices
Authors: Assmann Peter F. , Barreda Santiago , Nearey Terrance M.
Published: November 2013

At previous meetings, we presented data on the perception of speaker sex and age in children's voices. The stimuli common to these experiments were /hVd/ syllables in isolation and sentence context. Here we present the results of a modeling study in which acoustic measurements of the /hVd/ syllables were used to predict listener judgments of age and sex. Variables were selected based on preliminary analyses and suggestions from the literature: (1) duration; (2) average fundamental frequency; (3) geometric mean of F1 F2 F3; (4) magnitude difference between harmonics 1 and 2; (5) magnitude difference between harmonic 1 and F3 peak; (6) Cepstral pitch prominence; (7) Harmonic-to-noise ratio. Logistic regression models were constructed to predict listeners' judgments of speaker sex, and mixed effects linear regression models for speaker age. Results confirmed the importance of F0, formant frequencies and measures related to the voicing source for both age and sex. Regression coefficients for judgments of age and sex were similar to those for veridical age and sex when regressed on the same physical measures, suggesting a near-optimal use of cues by listeners.
Performance analysis of a matcher in a lexical access system based on landmarks and distinctive features
Authors: Kenney Jess , Paller-Rzepka Jason , Choi Jeung-Yoon , Shattuck-Hufnagel Stefanie
Published: November 2013

Performance characteristics of a prototype matcher in a lexical access system based on landmarks and distinctive features are analyzed. A database of 16 CONV files containing spontaneous American English utterances produced by 8 female speakers is annotated with words, and phone sequences derived from the word sequences are generated using the CMU phone-based dictionary. Predicted landmark and distinctive feature sequences are then generated using context-dependent rules from the phone sequences. These labels are used to map back to a lexicon which is also represented in terms of landmarks and distinctive features. The results for using core lexicons consisting of words within a CONV file show an average match rate of about 23% using only manner-class-related landmarks, and about 93% using the distinctive feature labels. Using an expanded lexicon combining all core lexicons lowers average match rates, by about 7% using landmark labels, and by 4% using the distinctive feature labels. These results provide characteristic rates for using linguistically motivated features to match to a lexicon, for both the landmark labels and for the more detailed distinctive feature labels.
Real-time speech masking using electromagnetic-wave acoustic sensors
Authors: holzrichter John f. , Ng Lawrence C. , Chang John
Published: November 2013

Voice activity sensors commonly measure voiced-speech-induced skin vibrations using contact microphones or related techniques. We show that micro-power EM wave sensors have advantages over acoustic techniques by directly measuring vocal-fold motions, especially during closure. This provide 0.1 ms timing accuracy (i.e., ~10 kHz bandwidth) relative to the corresponding acoustic signal, with data arriving ~0.5 ms in advanced of the acoustic speech leaving the speaker’s mouth. Preceding or following unvoiced and silent speech segments can then be well defined. These characteristics enable anti-speech waves to be generated or prior recorded waves recalled, synchronized, and broadcast with high accuracy to mask the user’s real-time speech signal. A particularly useful masking process uses an acoustic voiced signal from the prior voiced speech period which is inverted, carefully timed, and rebroadcast in phase with the presently being spoken acoustic signal. This leads to real-time cancellation of a substantial fraction of the voiced acoustic energy, as well as providing timing to mask the remaining un-canceled voiced speech energy, and unvoiced speech and silence periods.
Gender differences in the acoustic realization of creaky voice: Evidence from conversational data collected in Northern California
Authors: Podesva Robert J. , Szakay Anita
Published: November 2013

Although several sociophonetic studies report greater breathiness among female speakers, a pattern often attributed to sexual dimorphism in vocal fold physiology (Södersten and Lindestad, 1990), recent studies in North America report that young women use more creaky voice than men (Yuasa, 2011; Podesva, 2013). While these recent studies examine conversational data, they rely on auditory techniques to identify creaky phonation, leaving its acoustic realization in conversational speech largely unexplored. The present study investigates the acoustic properties of creaky voice in hour-long sociolinguistic interviews with 30 speakers (15 females, 15 males; age 18–86) from Northern California. Measures of spectral tilt were taken at the midpoint of all vowels in the corpus (N = 362,429), and data were fitted to a mixed effects linear regression model. As expected, several linguistic factors influence H1-H2 values (previous and following segment, intensity, F0, F1, vowel duration, stress, phrase position, phrase duration), alone and in interaction. With regard to social factors, H1-H2 is significantly lower for female speakers, indicating greater creak, even though the H1-H2 measure under-captures creakiness for female speakers (Simpson, 2012), and no age effect was observed. In sum, while females are generally creakier, apparent time data do not indicate that this is a recent trend.
Sensitivity analysis of the image source method to roughness and volume heterogeneities
Authors: Pinson Samuel , Holland Charles W.
Published: November 2013

In the context of the sediment characterization, the image source method provides a fast and automated sound-speed profile measurement of the seafloor. This technique is based on the analysis of the seafloor reflected acoustic wave as a collection of image sources whose positions are linked with the thicknesses and the sound speed of the sediment stack. The presence of interface roughness and volume inhomogeneities will reduce phase coherence between the receivers and thus may reduce the ability to precisely obtain the image source position. However, “blurring” of the image source position may provide useful clues about the roughness and/or volume heterogeneities. Recent measurements were obtained using an Autonomous Underwater Vehicle (AUV) towing a broadband source (frequency band from 1600 to 3500 Hz) and a linear array of hydrophones. Based on that configuration, a sensitivity study of the effect of roughness and volume heterogeneities on the image source method is presented and discussed.
Inversion of shear wave speed in coastal sediments using interface waves
Authors: Potty Gopu R. , Giard Jennifer , Miller James H. , Goldsberry Benjamin , Isakson Marcia
Published: November 2013

Shear speeds in semi-consolidated and consolidated shallow water sediments can significantly impact compressional wave attenuation and arrival times of acoustic normal modes. In addition shear properties of sediments are directly related to the strength of the sediments in geotechnical applications. All of these factors emphasize the importance of estimating shear speeds in shallow water sediments. One of the most promising approaches to estimate shear speed is to invert the shear speed profile using the dispersion of interface waves (Scholte waves). Interface wave data from a small scale experiment conducted in very shallow water in coastal Rhode Island will be presented. The University of Rhode Island’s shear measurement system consisting of vertical axis and 3-axis geophones were used to collect data in 3 m of water. Interface waves were excited by dropping a weight from a research vessel. Modeling of interface waves will be carried out using Finite Element Method (FEM) and a dynamic stiffness matrix model. Sediment properties will be inferred based on the modeling and data-model comparison. The estimated sediment properties will be compared with historic core data from the field test location. [Work supported by Office of Naval Research.]
Laboratory measurements of shear wave properties in marine sediments using bender element transducers
Authors: Lee Kevin M. , Ballard Megan S. , Bashyam Sanjai , Muir Thomas G.
Published: November 2013

In shallow water, acoustic propagation is often controlled by the properties of the seabed. In environments where the shear speed in the sediment approaches the sound speed in the water column, wave conversion at the bottom has been identified as a dominant loss mechanism. The ultimate goal of this work is to develop a device for measuring both compressional and shear wave properties in situ in marine sediments. This work presents laboratory measurements using bender element transducers to measure shear wave properties in marine sediments. The transducer consists of two long, thin piezoceramic plates rigidly bonded along their lengths driven 180 degrees out of phase in the length extensional mode so that the differential change in length of each plate causes the composite element to bend [J. Acoust. Soc. Am 63, 1643–1645 (1978)]. When the transducer is embedded in a medium, mechanical motion is transferred from the bender to the particles in the medium in a manner such that particle motion is perpendicular to the length dimension of the element. Laboratory measurements demonstrate bender sensitivity to low amplitude shear waves in sandy and muddy sediments. [Work supported by ARL:UT IR&D.]
An inverse method for estimating sediment sound speed
Authors: Lin Tao , Michalopoulou Zoi-Heleni
Published: November 2013

A fast approach for solving the inverse problem of estimating sediment sound-speed based on the Deift-Trubowitz trace formula is being investigated in our research. Under certain assumptions, this algorithm can recover the sound speed profile in the seabed using pressure field measurements in the water column at low frequencies. The inversion algorithm, employing a modified Born approximation, works well with synthetic data. Results are compared to those of previously developed methods and demonstrate improvement especially at sharp changes in sound speed. Although the method is stable and effective with noise-free data, problems arise when noise is considered. In our work, we develop regularization methods to remedy this problem. Finally, we recognize that some assumptions necessary for this algorithm to work may not be realistic; we discuss ways to relax these limitations. [Work supported by ONR.]
Modeling the free vibrations of an acoustic guitar top plate
Authors: Shepherd Micah R. , Hambric Stephen A. , Wess Dennis B.
Published: November 2013

Using computer models to simulate the sound of an acoustic guitar can significantly decrease lead time for new designs. In order to create an accurate computer model of a Dreadnought-style acoustic guitar, a sequential modeling approach was used. A finite element model of a bare top plate with braces and a bridge plate was created. The top and plate and braces were modeled as plate elements with orthotropic material properties. The natural variation of the wood properties was also examined along with their dependence on moisture content. The modes of the model were then compared to experimentally obtained modes from top plate prototypes. The modeshapes of the model compared well to those measured. Uncertainty analysis was also performed and the statistical bound of natural error between wood samples was determined to be approximately 8%. The natural frequencies of the model fell within the error bound for lower-order modes but diverged slightly for several higher-order modes. These results indicate the importance of using accurate material properties in models of acoustic guitars.
Range of variability in native and non-native spontaneous speech intervocalic stops
Authors: Simonet Miguel , Warner Natasha L. , Brenner Dan , Hoffmann Maureen , Morales Andrea , Baltazar Molina Alejandra
Published: November 2013

Speakers produce sounds differently in spontaneous vs careful speech, and how they do this shows both similarities and differences across languages. The current project examines spontaneous conversational speech and read speech among monolingual English speakers, Dutch-English bilinguals, and Spanish-English bilinguals (for Dutch and Spanish, in both their L1 and English). The phonology of intervocalic stops differs in these languages: Dutch has final devoicing, Spanish has approximation of /bdg/, and English has flapping of /td/. In our recordings, Dutch speakers often devoiced final stops in both Dutch and English in spontaneous speech, while native English speakers produced voiced stops or approximants. Speakers of all the languages produced some approximant realizations and some deletions. Through measurements of consonant duration, amplitude dip during the consonant, and cessation of voicing, this work shows the range of acoustic variability produced by speakers of three languages in their L1 and their L2, in spontaneous and careful speech. This allows a comparison of how much of speech variability stems from the native language phonology, from language-specific phonetics, and from language-general spontaneous speech reduction.
Intelligibility of speaking styles elicited by various instructions
Authors: Gilbert Rachael C. , Victor Nicholas , Chandrasekaran Bharath , Smiljanic Rajka
Published: November 2013

The acoustic-phonetic modifications made by talkers are attuned to the specific communicative situations that listeners are experiencing (Lam and Tjaden, 2013; Hazan and Baker, 2011). The extent to which such modifications are under explicit control remains largely unknown. This study examined the extent to which native and non-native talkers can implement acoustic-articulatory enhancements following specific instructions and the extent to which these changes will improve intelligibility. Ten native and 10 Korean-accented talkers read sentences in various styles including in conversational and clear speech, while imitating a native speaker’s conversational and clear speech, with exaggerated vowels, more slowly, and more loudly. Sentences were mixed with noise (−5 dB SNR) and presented to native listeners. Intelligibility results revealed that nonnative talkers were overall less successful in enhancing intelligibility following different instructions compared to native talkers. Instructions to speak clearly and imitating native clear speech sentences provided the largest intelligibility benefit while the instructions to slow down were least successful in improving intelligibility across talkers. Speaking loudly and exaggerating vowels increased intelligibility only for native talkers. Acoustic analyses will examine which acoustic-phonetic changes were implemented following each instruction. The results have important implications for enhancing intelligibility in difficult communicative situations (e.g., classrooms).
Prosodic characteristics in Japanese speech by Taiwan Mandarin speakers and native Japanese speakers
Authors: Ogasawara Naomi , Vance Timothy J. , Shih Chia-Lin
Published: November 2013

Previous studies (Ishihara et al., 2011; Sato 1995) show that prosody contributes more to native-like accents than segments do. It was also found that compared with errors in timing, errors in pitch accent in Japanese speech were more tolerable to native and non-native speakers. This suggests that non-native speakers pay less attention to pitch accent when speaking Japanese; as a result, their acquisition of correct pitch accent does not progress as their overall Japanese proficiency improves. In this study, Taiwan Mandarin speakers and native Japanese speakers produced Japanese words with different syllable structures, some containing all short syllables and others at least one long syllable. These words are 2 to 4 moras long and have nine pitch accent patterns. Each participant produced each word in isolation and in a carrier sentence. All speech data were acoustically analyzed to measure (1) the highest F0 point in accented syllables and (2) the difference in F0 between an accented syllable and adjacent unaccented syllables. The purpose of this study is to investigate common F0 patterns in pitch accents among native and non-native speakers of Japanese, and common pitch accent errors made by the non-native speakers.
The adaptation of tones in a language with registers: A case study of Thai loanwords in Mon
Authors: Silpachai Alif
Published: November 2013

How do tones get adapted into languages with registers? This study examined loanword adaptation in which a language with registers borrows words from a language with lexical tones. In particular, this study presents an acoustic analysis of Thai loanwords in Mon, a language with two registers—one with tense voice and high f0 and the other with lax voice and low f0 accompanied by breathy voice. To investigate phonetic realizations, eight Mon speakers native to Thailand were recorded uttering 135 Thai loanwords in a carrier sentence. Results show that the tones in Thai loanwords get adapted as four level tones in Mon. In particular, loanwords with high tone have the highest f0, loanwords with mid tone have the second highest f0, loanwords with low tone and rising tone have the third highest f0, and loanwords with falling tone have the lowest f0. It is puzzling why Thai falling tone—not low tone—gets adapted as the lowest f0 in Mon. Results suggest that Mon spoken in Thailand may be developing lexical tones due to language contact.
Perception of epenthetic vowels in English /s/-initial clusters by Spanish-speaking second language learners of English
Authors: Martinez-Garcia Maria Teresa , Tremblay Annie
Published: November 2013

Second language learners’ (L2ers’) perception and production of consonant clusters is influenced by the syllable structure of the native language (L1). This study investigates whether the perception of epenthetic vowels is partially responsible for why Spanish speakers have difficulty producing /s/ + Consonant (“sC”) clusters in English, and whether it affects word recognition in continuous speech. Spanish, German L2ers of English, and native English speakers completed: (i) an AXB task with (/ə/)sC-initial nonce words (e.g., [əsman]-[sman]); (ii) a word monitoring task with (/ə/)sC-initial words in semantically ambiguous sentences (e.g., I have lived in that (e)state for a long time); and (iii) a production task with the same sentences as in (i). L2ers also took a word-familiarity rating task and a cloze test to assess their proficiency. For (i) and (ii), accuracy rates were recorded, and response times were measured from target onset. For (iii), acoustic analyses showed whether the L2ers’ productions of sC-initial words contained an epenthetic vowel. Preliminary results suggest that perception difficulties may be partially responsible for Spanish speakers’ production and word-recognition difficulties with sC-clusters in English, but production data suggest that articulatory problems may also play an important role. Proficiency does not seem to help overcome this difficulty.
Familiarity with a foreign accent aids perceptual accent adaptation
Authors: Blanco Cynthia P. , Tagtow Emily , Smiljanic Rajka
Published: November 2013

A change in speaker accent is reported to temporarily slow speech processing (Bradlow and Bent, 2003; Clarke and Garrett. 2004). Recent work suggests that this delay may be an artifact of task expectations and reflects a surprise effect, not the time needed for accent adaptation (Floccia et al., 2009). The present study tested listeners with high and low exposure to Spanish- and Korean-accented English to determine if frequent exposure to these accents decreases the surprise effect in an experimental setting. Participants listened to four blocks of meaningful sentences and responded to probe words; they heard a native-accented speaker in the first block and either native-, Spanish- or Korean-accented speakers in blocks 2 and 3. Results thus far show that the change from native-accented to foreign-accented speaker (block 1 to block 2) elicited a processing delay for participants in the Korean-accented condition, but not in the Spanish-accented condition. This pattern remained, but was somewhat attenuated, in the change from block 2 to block 3, when voice but not accent changed. These results show that extensive experience with a particular foreign accent (Spanish) outside the lab results in a smaller processing cost when listening to accented speech in the lab.
White-matter microstructure differs in adult bilingual and monolingual brains
Authors: Kuhl Patricia K. , Richards Todd L. , Stevenson Jeff , Can Dilara D. , Wroblewski Liv , Fish Melanie S. , Mizrahi Julia
Published: November 2013

Behavioral research indicates that bilingual children and adults outperform monolinguals at executive function tasks, especially those related to cognitive flexibility, suggesting that experience with two languages alters brain structure. We investigated white-matter microstructure using Tract-Based Spatial Statistics (TBSS) in monolingual (n = 15) and Spanish-English bilingual (n = 16) adults, quantifying fiber tract organization in measures of directionality (fractional anisotropy, FA) and diffusivity perpendicular to the main axonal direction (radial diffusivity, RD). FA was significantly higher for monolinguals (p < 0.05, corrected) in three brain regions: the right posterior limb of the internal capsule, the right sagittal stratum that includes inferior frontal occipital fasciculus, and the right thalamus. RD was greater for bilinguals (p < 0.05, corrected) in multiple brain areas, most prominently in the cerebellum, inferior frontal occipital fasciculus, and superior longitudinal fasciculus. We interpret these differences in brain structure between monolinguals and bilinguals as consistent with the idea that bilingual language experience leads to a pattern of more diffuse connectivity in the brain, which may be related to increased cognitive flexibility skills.
Acoustic scattering from ocean sediment layers with multiple rough interfaces using finite elements
Authors: Isakson Marcia J. , Chotiros Nicholas P.
Published: November 2013

Acoustic scattering from the ocean bottom is a major component in shallow water reverberation and propagation as well as having a significant effect on the transmission of acoustic communication. However, boundary element models can only model scattering from a single rough interface. While some scattering models, such as the GeoAcoustic Bottom Interaction Model (GABIM), have considered scattering from layered sediments, these models are normally constrained to only one rough interface. Finite element models have been shown to accurately model scattering from both fluid and elastic boundaries, and, unlike conventional models based solely on the Helmholtz-Kirchhoff integral, are not limited to boundary interactions. In this study, a two-dimensional finite element model for scattering from two fluid layers and a fluid layer over an elastic layer is compared with perturbation theory and Kirchhoff approximation models to test the validity of considering the considering underlying interfaces flat. [Work sponsored by ONR, Ocean Acoustics.]