bluuebunny/crossref_metadata_2025 huggingface dataset:
Measured power law attenuation of shear waves in swine liver
Authors: Grosz Steven A. , Pereira Rebeca , Urban Matthew W. , McGough Robert
Published: April 2019

To characterize the attenuation and dispersion behavior of shear waves in excised swine liver samples, the complex shear modulus was measured with a Rheospectris C500 + from 10 Hz to 2000 Hz. The shear wave attenuation and shear wave speed were calculated from the complex modulus measurements. A power law fit was evaluated for the shear wave attenuation, and a power law fit with and without a constant offset was evaluated for the shear wave speed. The power law closely matches the measured shear wave attenuation over most of the frequency range evaluated, although some differences are observed in several of the samples below 400 Hz. The power law without the constant offset closely matches the measured shear wave speed above 200 Hz in all measurements, where the addition of the constant offset achieves a much closer fit in all measurements that contain discrepancies below 200 Hz. The results demonstrate that shear wave attenuation in swine liver follows a power law and that a power law with a constant offset is an effective model for the shear wave speed in swine liver. [Work supported in part by NIH Grants DK092255, EB023051, and EB012079.]
Developments in underwater thermophones
Authors: Mayo Nathanael K. , Schumacher Christian , Blottman John B. , Howarth Thomas R.
Published: April 2019

Thermophones are acoustic projectors powered by resistive heating elements. The thermophone was invented shortly after Alexander Graham Bell’s invention of the telephone, and since then, thermophone development has primarily focused around its use in air. Thermophones have historically been used as a precision source of sound for calibrating microphones and have been unable to break out of this limiting role largely due to device inefficiencies. The recent implementation of nanomaterials, which greatly improve the overall electric to acoustic conversion efficiencies, has brought about a resurgence of interest surrounding these devices; however, practical applications remain elusive. One of the most likely fits for this unique technology is as an underwater projector. Recent calibrated acoustic testing on various designs of encapsulated underwater thermophones reinforces our notional assumptions of the electro-thermo-acoustic transduction process as well as the general effect of various device parameters on acoustic performance. While efficiency is still a major concern, thermophones possess many other desirable features such as their low cost, wide bandwidth, and ability to produce low frequencies in a compact package.
On the downward direction of the flat panel display speaker
Authors: Park Hyung Woo , Lee SungTae , Park Kwanho , Bae Myungjin
Published: April 2019

Information display devices are being advancement by ICT development. Particularly, besides the image quality and appearance design of the information display device, the development of the accompanying elements such as the sound quality is also progressed. Conventional information display devices such as LCD and LED TV have focused on the pixel configuration and color implementation and developed to such an extent that the human eye can not follow it, and the image quality is as good as the actual view in a proper field of view. However, in the case of sound, it has occurred at various alternative positions with the limitation that it cannot penetrate the hard screen. In the case of a flat-screen TV, however, the position of the sound was properly configured by reproducing the sound directly from the left and right sides of the screen. However, focusing on the image quality and design elements, it was hidden above. With several experimental factors, we were able to reproduce a lot of sound from the bottom speaker. This is disadvantageous in that it cannot hear the reproduced sound directly, hears mainly the reflected waves of the space below the space where the information display device is located, and hears different sounds depending on the characteristics of the reflection surface. In this study, we introduce a technique to make a sound with a direct screen that complements these shortcomings.
The international Noise Awareness Day in Germany
Authors: Schulte-Fortkamp Brigitte
Published: April 2019

The International Noise Awareness Day in Germany was organized first time in 1998 and will have on 24 April 2019 his 22nd yearly event. The sensitization in relation to the problem of noise along with the spreading of knowledge about causes and consequences of noise (both socially and health wise) is elementary constituents of the “Tag gegen Lärm” (Noise Awareness Day). Through its continuity over the past 22 years and its public acceptance, the “Tag gegen Lärm” has become an institution that has a permanent place in Germany’s calendar. The “Noise Awareness Day” is aiming everyone who is interested in noise, its causes, consequences, and countering, including people affected by noise, subject-specific interested groups, and people with political responsibilities (citizens, economy, and politics). The “Noise Awareness Day” happens every year in April, always scheduled coordinated with the “International Noise Awareness Day” organized by the Center for Hearing and Communication (CHC) USA. Current work and activities will be presented.
Soundprint and the ASA's International Noise Awareness Day Campaign—Results, what worked, and going forward
Authors: Farber Gregory S.
Published: April 2019

SoundPrint, a crowdsourcing app that objectively measures noise levels of venues and described as “Yelp for Noise,” partnered with the Acoustical Society of America (ASA) for International Noise Awareness Day in 2018 and 2019 to raise noise pollution and hearing health awareness. SoundPrint served as the technological tool by which the public used to “via their sound level submissions” to show the public that noise is an important public health issue. The 2018 INAD campaign’s initial success led to a significant bump in the number of crowdsourced submissions to SoundPrint’s database spanning numerous countries, states, and cities (figures will be presented). The campaign was supported with specific marketing content on noise pollution and hearing health that raised visibility for both INAD and ASA. The presentation will discuss data results associated with the campaign, marketing methods used to raise awareness, and subsequent steps other organizations can employ to further ASA’s cause going forward.
Centers for Disease Control and prevention efforts to increase awareness and prevention of noise-induced hearing loss
Authors: Carroll Yulia , Eichwald John
Published: April 2019

For 45 years, the Centers for Disease Control and Prevention (CDC) has researched noise induced hearing loss (NIHL) in the workplace and disseminated its research to prevent occupational hearing loss. Additionally, CDC has made research and educational materials available on hearing loss in children. In 2015, CDC received inquiries from the public and medical community about NIHL in non-workplace settings. In response, CDC began efforts to raise public awareness of NIHL and awareness about how to prevent its health effects. A CDC intra-agency working group collaborated with the World Health Organization, the National Institute on Deafness and Other Communication Disorders and the Dangerous Decibels® program for the promotion of the materials including (1) MMWR Vital Signs: Noise-Induced Hearing Loss Among Adults—United States 2011–2012; (2) CDC Public Health Grand Rounds: Promoting Hearing Health Across the Lifespan; (3) World Hearing Day educational materials; and (4) MMWR: Use of Personal Hearing Protection Devices at Loud Athletic or Entertainment Events Among Adults — United States, 2018. Additionally, CDC scientists and communicators continue to leverage internal and external channels for developing materials and spreading the word about the prevention of NIHL at work, at home and in communities.
Data-driven interpretable models of wave dynamics for infrasound monitoring
Authors: Millet Christophe , Lott Francois
Published: April 2019

Accurate and efficient models are essential to understand and predict acoustic signals propagating in the atmosphere. In many practical problems such as source localization and yield estimation, multiple models for describing the atmospheric fluctuations and infrasound are available, with varying approximation qualities. In standard practice, inferences are exercised as if the selected models had generated the observations. This approach ignores the model uncertainty, leading to biased inferences and to estimates that may be extremely sensitive to tunable parameters. This work explores a hierarchical Bayesian framework for producing interpretable models for both atmospheric gravity wave (GW) dynamics and acoustic propagation, from ground-based infrasound measurements. It is shown that there are only a few important terms that govern the GW dynamics and the interactions with infrasound. The resulting GW models can either be incorporated into global climate models to better describe the effects of GWs on the global circulation or used together with infrasound propagation models for improving inference accuracy and efficiency. This perspective, combining the resulting infrasound-driven models with sparse sensing and machine learning to monitor the atmosphere, is explored using recurring events such as the ammunition destruction explosions at Hukkakero, in northern Finland.
The sub-microbarom notch in acoustic wind-filter response
Authors: Gabrielson Thomas B.
Published: April 2019

The measurement of the frequency response of infrasound elements with spatial-averaging wind filters is often done by comparison with a reference sensor and with ambient noise as the excitation. Frequently, a notch appears in the response just below the microbarom band—a notch that is not explained by the acoustics of the wind filter. In fact, this notch is diagnostic of the spatial averaging of wind-associated turbulence. The frequency region of the notch is bounded above and below by regions in which excellent determinations of response can be made (1) below the notch under moderate- to high-wind conditions where the scale of the turbulence exceeds the scale of the wind filter rendering the wind filter ineffective and (2) in the microbarom region where the acoustic component is strong and coherent across the entire wind-filter aperture. Furthermore, the phase of the response is not affected in the region of the notch. Consequently, the true acoustic response can be estimated in the notch region in several ways. It would, however, be a mistake to ignore the information about the effectiveness of the wind filter that, in effect, creates the notch.
The transition of gravity wave or mesoscale flow to boundary layer turbulence and implications for infrasound propagation conditions
Authors: Assink Jelle D. , Lyons Gregory W.
Published: April 2019

Knowledge of the atmospheric boundary layer (ABL) is important for weather and climate forecasting as well as infrasound detection. In spite of many advances, the ABL is still not represented realistically in weather models, which leads to uncertainties in weather predictions. At the same time, the influence of the ABL on infrasound detectability is not well understood, which potentially limits the capability of the technique. In this work, a network of anemometers, microbarometers, and ceilometers is used to characterize gravity wave activity and turbulence in the ABL. The sensors are co-located at the Cabauw Experimental Site for Atmospheric Research (CESAR). The sensor network allows for the estimation of velocity and pressure spectra, as well as boundary-layer structure and mixing height. The goal of this work is to study the transition from gravity wave or mesoscale flow to boundary layer turbulence and to consider implications for infrasound propagation conditions. Here, an analysis of spectra under convective and stable conditions is presented with respect to both gravity wave and boundary-layer turbulence theory. Observed distinctions in the velocity and pressure spectral transitions will be discussed, including large-scale turbulence and the mesoscale spectral gap.
Assessment of a feasible virtual acoustics method for testing hearing aids using the Hearing-Aid Speech Perception Index
Authors: Cho Sungbeen , Aker Scott , Macpherson Ewan A.
Published: April 2019

Significant differences have been found in hearing aid (HA) performance between laboratory and real world test environments. Virtual sound environments provide a degree of control and reproducibility which is lacking in real world testing but may require an impractical number of loudspeakers. We assessed the accuracy of a simulation approach in which sources’ direct sound is delivered by single loudspeakers while room acoustics are reproduced using low-order Ambisonics and a small number of loudspeakers. In a large office, we recorded binaural hearing aid output in response to sentence targets and babble noise presented at various levels and from various combinations of four loudspeakers surrounding a manikin. We measured the loudspeakers’ room impulse responses (IRs) using a 32-channel spherical microphone array (Eigenmike), and split the IRs into "direct sound" and "room sound" portions. In an anechoic chamber, the original acoustics were simulated using Ambisonics or discrete loudspeakers for each source’s direct portion and Ambisonics for the room portion. Ambisonic order and/or number of playback loudspeakers were also varied. HA output in the simulations was recorded using the manikin and assessed by comparing Hearing-Aid Speech Perception Index (HASPI) values computed on the simulation recordings with those made in the original room.
A parametric resonance based capacitive ultrasonic transducer for wireless power transfer in air
Authors: Surappa Sushruta , Degertekin F. Levent
Published: April 2019

Capacitive ultrasonic transducers have been in use for many years for various applications such as medical imaging, wireless power, sensing, and nondestructive testing. Typically, capacitive transducers require a DC bias or electret in order to operate efficiently and with high sensitivity. This makes them less desirable for applications such as wireless power transfer or energy harvesting, where a passive piezoelectric transducer may be preferred. Recently, it was shown that the requirement of a DC bias can be overcome by driving the capacitive transducer into parametric resonance using ultrasound (Surappa et al., Appl. Phys. Lett. 111(4), 043503). In this work, we present the operation of the first ever biasless, chargeless capacitive parametric ultrasonic transducer (CPUT) in air and demonstrate the utility of such a system for acoustic power transfer and sensing. Experiments performed in air show that the CPUT has an open-circuit sensitivity of more than 100 mV/Pa and is able to recover 31 µW at a distance of 10 cm from a 50 kHz ultrasonic source in the absence of a DC bias.
Personalizing head-related transfer functions using anthropometric measurements by combining two machine-learning models
Authors: Lee MingYang , Lawless Martin S. , Baglione Melody
Published: April 2019

Virtual reality (VR) requires rendering accurate head-related transfer functions (HRTF) to ensure a realistic and immersive virtual auditory space. An HRTF characterizes how each ear receives sound from a certain location in space based on the shape of the head, torso, and pinnae, and provides a unique head-related impulse response (HRIR) for each given source location. Since HRTFs are person-specific and difficult to measure, recent research has utilized pre-existing HRTF databases and anthropometric measurements to generate personalized HRTFs with machine learning algorithms. This study investigates a personalization method that estimates the shape of each ear’s HRIR and interaural time differences (ITD) between the two ears in separate models. In the proposed method, the shape of the HRIR is estimated with an artificial neural network (ANN) trained with time-aligned HRIRs from the CIPIC database, eliminating between-subject timing differences. A regression tree is used to estimate the ITDs, which are integer sample delays between the left and right ears. A localization test with a VR headset was conducted to evaluate the perceptual accuracy of the personalized HRTFs. Subjects completed the test with both a pre-selected average HRTF and their personalized HRTF to compare localization errors between the two conditions.
Employing braid theory to disentangle overlapping oceanic events in the shallow water acoustic channel
Authors: Sen Gupta Ananya , McCarthy Ryan
Published: April 2019

The shallow water acoustic channel is well-known to exhibit rapid temporal fluctuations due to multipath effects, fluid motion as well as focusing events in the ocean. These events often overlap temporally thus contributing in unpredictable ways to the channel delay spread. We will present recent results from employing geometric signal processing techniques to shallow water channel estimation and will introduce new ways to identify and disambiguate overlapping oceanic phenomena within the channel delay spread. Specifically, we will explore how geometric braid theory and related operations can be employed to disentangle overlapping channel braids, and explore the efficacy of such signal processing techniques across diverse channel representations. Finally, we will discuss the importance of capturing oceanic phenomena at the appropriate resolution of time, frequency, and sparsity and the trade-offs in accuracy involved based on the chosen channel representation(s).
Initial results in designing an acoustic sound simulator for heavy equipment
Authors: Wells Nathaniel , Sommerfeldt Scott D. , Blotter Jonathan
Published: April 2019

This paper focuses on the initial development of a vehicle cab sound simulator. This sound simulator has two objectives. First, it can be coupled with a visual simulator and used for operator training. Second, it will be used by designers such that when structural modifications are made to the vehicle, the acoustic response and sound quality in the cab can be predicted. To begin to understand and implement this simulator, transfer functions were measured for several structures progressing from simple to complex and used to generate a simulated signal. Post-processing techniques were used to improve the overall quality of the simulated responses. Similarly, the structures were recreated in a numerical software package, where the transfer functions were calculated numerically and used to generate simulated responses. These signals were compared to the measured response of the system and auralized to determine the effectiveness of the simulation.
Effect of trading-off office background and intermittent noise levels on performance, annoyance, distraction, and stress
Authors: Lawless Martin S. , Rusk Zane T. , Vigeant Michelle C. , Dittberner Andrew
Published: April 2019

In open-plan offices, work performance is affected by the acoustic environment, which includes steady-state broadband noise and intermittent, occupancy-generated noise. High levels of broadband noise (e.g., HVAC noise) can mask intermittent sounds to reduce distraction, but risk causing fatigue and other noise-related symptoms that may be detrimental to performance. In this study, the impact of the acoustic environment on work performance was investigated by adjusting the relative levels of both broadband and intermittent noise. Participants were exposed to four different acoustic environments, either starting with high background noise and low intermittent levels or vice versa. While in each background condition, the subjects performed four cognitive tasks that evaluated memory, attention, reasoning, and planning skills, respectively. Heart rate variability and electrodermal activity (EDA) were measured to gauge arousal (stress levels) in each environment. After each exposure, participants were asked to rate annoyance, distraction, fatigue, and stress, among other subjective attributes. The EDA and ratings of distraction significantly increased as the intermittent noise levels increased, while noise annoyance ratings were consistent across each background condition. Additionally, performance on the cognitive tasks was impacted by the order in which the participants experienced the acoustic environments.
Exploring the use of exploding oxy-acetylene balloons for field-scale infrasound
Authors: Neilsen Tracianne B. , Maher Sean , Lysenko Eric J. , Escobedo Julio A. , Shaw Sarah A. , McKay Margaret G. , Hawkes Menley R. , Lopez Christian A. , Butts Carla , Matoza Robin S.
Published: April 2019

Fundamental aspects of volcano-acoustic wave propagation and source effects, such as seismo-acoustic coupling, can be explored with field-scale experiments. Buried explosives are often used for these tests but require special permission and personnel. As an alternative, we explored using an environmentally friendly source of high-amplitude noise: balloons filled with a stoichiometric oxy-acetylene mix detonated with an electric match. A field-scale experiment was conducted to test the efficacy of exploding oxy-acetylene balloons to generate infrasound and modest seismic vibrations. In prior studies with these exploding balloons, the balloons were positioned above the ground to test nonlinear propagation theory [Young et al., J. Acoust. Soc. Am. 138, EL305–EL310 (2015)] and quantify Mach Stem formation [Leete et al., J. Acoust. Soc. Am. 138, EL522–EL527 (2015)]. In the present experiment, the balloons were placed on the ground in “craters.” Specifically, 17 in. oxy-acetylene balloons were exploded in three different “crater” shapes and while sitting on the ground as a control. The explosions were recorded at 100-160 m on colocated infrasound sensors, and broadband seismometers microphones at different heights. The 17 in. oxy-acetylene balloons produce significant infrasound with peak levels at 100 m of 5-13 Pa depending on type of “crater.”
Spatio-temporal observations of temperature and wind velocity using drone-based acoustic atmospheric tomography
Authors: Finn Anthony , Rogers Kevin , Meade Joshua , Skinner Jarrod , Zhargarian Amir
Published: April 2019

This paper reports on a sequence of trials in which the acoustic signature of a small remotely piloted vehicle (drone) has been used to obtain spatio-temporal estimates of atmospheric temperature and wind vectors. Sound fields are recorded onboard the aircraft and by microphones on the ground. Observations are compared and the resulting propagation delays computed for each intersecting ray path transecting the intervening atmosphere. A linear model of sound speed corresponds to virtual temperature and wind velocity, plus tomographic inversion combined with regularisation, then allows vertical cross-sections and volumes of temperature and wind profile to be computed. These two- and three-dimensional profiles are represented as a lattice of elliptical radial basis functions, which enables the medium to be visualised at high levels of resolution. The technique has been used to provide spatio-temporal visualisation of atmospheric dynamics up to altitudes of 1200 m over baselines of 600 m. Independent measurements taken by co-located instruments such as a Doppler SODAR, ZephIR 300 LIDAR and temperature sensors carried onboard drones flying within the remotely sensed atmosphere show real world performance suggests accuracies of around 0.3 °C, 0.5 m/s and 0.2 m/s for temperature, horizontal and vertical wind speeds respectively may be anticipated. The real world performance also compares very favourably to error envelopes anticipated from propagation models based on large eddy simulation.
Preliminary attempts to isolate ground-radiated noise from exploding balloons
Authors: Lysenko Eric J. , Neilsen Traci
Published: April 2019

Seismo-acoustic coupling occurs when seismic wave propagation creates air-borne acoustic signals. Research is ongoing to determine methods to distinguish between sound due to seismo-acoustic coupling and purely air-borne transmission. In a field experiment, we detonated 17 in. balloons filled with a stoichiometric oxy-acetylene mix placed both on and in the ground. We attempted to isolate ground-radiated waves by constructing a portable soundproof box to deaden air-borne sound wave. The box was constructed from mass-loaded vinyl, soundproofing composite board, liquid nails, and Green Glue. This design incorporated soundproofing through decoupling, absorption, and insulation techniques. Signals observed from a microphone placed in the box are compared with those obtained on microphones outside the box at various heights. The initial blast wave was not evident inside the box. However, the loudest sound measured in the box matches a subsequent portion of signals on microphones near the ground. Testing in a reverberation chamber is done to measure the frequency response in the transmission loss through the box. These results could suggest a viable technique for isolating ground-borne acoustic waves, which could be useful in experiments where calculating the coupling effect is impractical.
Auditory sensation of impulsivity and tonality in vocal fry
Authors: Aichinger Philipp , Roesner Imme , Schoentgen Jean
Published: April 2019

Vocal fry is a phonation type characterized by nearly complete vocal tract damping during the closed glottal cycle phase, caused by a low vocal frequency in combination with a long glottal closed phase. Auditorily, vocal fry is characterized by the sensation of individual glottal cycles. Vocal fry may be (para-)linguistically relevant, but it may also be a symptom of a voice disorder. The aim of the study is to develop predictive models of the presence of vocal fry based on data from auditory experimentation using synthetic stimuli. Predictors are the vocal frequency, the glottal open quotient, and the glottal pulse skewness. The vocal tract is kept constant. Tests are conducted with stimuli that are temporally homogeneous in terms of voice quality, as well as with stimuli that contain neutral-fry-neutral voice quality transitions. Listeners rate tonality, impulsivity, and naturalness of stimuli on 7-point scales, as well as the presence of vocal fry on a dichotomous scale. Results show that perceived vocal fry is correlated with an increase in perceived impulsivity and a decrease in perceived tonality of the voice. The most important predictor of vocal fry is vocal frequency, whereas open quotient and skewness appear to play a minor role.
Segmental duration as a cue to sentence structure
Authors: Knutsen Sten , Stromswold Karin , Kleinschmidt Dave F.
Published: April 2019

In order to parse speech in real time, listeners should use any informative cues available. Here, we investigate the role of segmental duration. Previous work has found statistically significant differences in the mean durations of analogous segments across different lexical/syntactic structures. However, a difference in means does not necessarily mean that the distributions of these durations make individual token durations sufficiently informative to be a useful cue. The goal of this work is to use production data to quantify how informative segmental duration is about syntactic/lexical structure. Our model is based on an ideal listener model, where we assume listeners have implicit knowledge of segmental duration distributions for active and passive sentences. Given these distributions, the model can infer the posterior probability that a particular token belongs to one distribution or the other. After implementing our model in a Bayesian classifier, our results indicate there is indeed sufficient information contained in individual token durations so as to be useful in real-time sentence processing. Furthermore, we modeled listener behavior in a gating task with syntactically ambiguous sentences truncated before disambiguating morphosyntax and achieved 74% accuracy in predicting syntactic outcome, similar to accuracy reported in behavioral studies (62%–84%).
Bidirectional effects of priming in speech perception: Social-to-lexical and lexical-to-social
Authors: Bouavichith Dominique A. , Calloway Ian C. , Craft Justin T. , Hildebrandt Tamarae , Tobin Stephen J. , Beddor Patrice S.
Published: April 2019

Previous perceptual research demonstrates that providing listeners with a social prime, such as information about a speaker's gender, can affect how listeners categorize an ambiguous speech sound produced by that speaker. We report the results of an experiment testing whether, in turn, providing listeners with a linguistic prime, such as which word they are about to hear, affects categorization of that speaker's gender. In an eye-tracking study testing for these bidirectional effects, participants (i) saw a visual prime (gender or lexical), (ii) heard an auditory stimulus drawn from a matrix of gender (female-to-male) and sibilant frequency (shack-to-sack) continua, and (iii) looked to images of the non-primed category. Social prime results replicate earlier findings that listeners’ /s-ʃ/ boundary can shift via visual gender information. Additionally, lexical prime results indicate that listeners’ judgments of speaker gender can shift with visual linguistic information. These effects are strongest for listeners at category boundaries where linguistic and social information are least prototypical. In regions of high linguistic and social prototypicality, priming effects are weakened or reversed. The results provide evidence of a bidirectional link between social and linguistic categorization in speech perception and its modulation by the stimulus prototypicality.
Perceptual preference for falling tones over rising tones: A study of Mandarin Chinese
Authors: Zeng Yuyu , Jongman Allard , Sereno Joan A. , Zhang Jie
Published: April 2019

Typological studies have shown that there are more falling tones than rising tones in tone languages, including Chinese. We test the hypothesis that this may be due to a perceptually-based advantage for falling tones over rising tones. Two acoustically comparable (and matched for naturalness) tonal continua in Mandarin (level-falling T1-T4, and level-rising T1-T2) were created. Identification and discrimination results were obtained from 14 native Mandarin speakers. The results revealed that it is easier to identify a falling tone than a rising tone; that is, listeners require a smaller F0 difference between onset and offset to distinguish a falling tone from a level tone as compared to a rising tone from a level tone. Additionally, there are several hints of better discrimination for the falling continuum. This disagrees with our and others’ Mandarin production data, which show that the rising tone is closer to the level tone than the falling tone is, hence a production-perception dissociation. We propose that, historically, Chinese listeners’ greater sensitivity to the level-falling contrast has resulted in the preponderance of falling tones over rising tones found across Chinese languages, and this proposed explanation may be applicable to other tone languages as well.
Acoustic cues to perception of labialized stops in a merger in progress
Authors: Culnan John , Yiu Suki
Published: April 2019

In Hong Kong Cantonese, the labialized and plain velar (/kw/ and /k/) are undergoing a merger where both may be produced as [k] before the vowel /ɔ/. This study examines the role of acoustic cues to labialization in the perception of velars in Hong Kong Cantonese, and whether these cues are utilized differently in the merger environment than other environments. Native listeners of Hong Kong Cantonese completed an identification task comprised of LPC resynthesized words of Cantonese in the merger environment and three other (unrounded) vowel environments. As anticipated initial results suggest that F2 transition is a less important cue for velars preceding /ɔ/ than those preceding other vowels, although surprisingly F1 transition may only be important for velars preceding /ɔ/. An examination of the importance of intensity suggests that this cue is not used in distinguishing labialized from plain velars. Finally, perception accuracy results on unchanged productions suggest that distinguishing labialized velars from plain velars is a more difficult task in the merger environment than other environments. Taken together, the pilot results suggest that native listeners of Hong Kong Cantonese rely more on multiple acoustic cues in environments where a single cue provides less certain information.
Prediction of listener perception of place-of-articulation in reduced speech
Authors: Willi Megan M. , Warner Natasha L. , Story Brad H.
Published: April 2019

Previous research on stop consonant production found that less than 60% of the stops sampled from a connected speech corpus contained a clearly defined hold duration followed by a plosive release [Crystal and House, JASA(1988)]. How listeners perceive reduced, voiced stop consonant variants is not well understood. The purpose of the current study was to investigate whether an acoustic cue called a relative formant deflection pattern was capable of predicting listeners’ perceptions of these approximant-like, voiced stop consonants variants. A new methodology motivated by a computational model of speech production was used to extract relative formant deflection patterns from excised VCV segments from a reduced speech database. Participants listened to a total of 56 excised VCV stimuli containing approximant-like, voice stop consonant variants and performed a force choice test (i.e., /b-d-g/). The agreement between the perceptions predicted by the relative formant deflection patterns and listeners’ behavioral performance was compared. The expected relative formant deflection pattern correctly predicted listeners' primary response for percent /b/ and /g/ identifications, but not for listeners’ percent /d/ identifications. The implications of these results on a possible invariant acoustic correlate for listeners’ perceptions of place-of-articulation information will be discussed.
Introducing Feelix, a digital stethoscope incorporating active noise control and automatic detection of lung sound abnormalities
Authors: West Elllington , McLane Ian , McLane Daniel , Emmanouilidou Dimitra , Elhilali Mounya , West James E. , Ward Arthur , Busch-Vishniac Ilene , McLane Jaishree , Dottin-Haley Brandon
Published: April 2019

Pneumonia is the top disease killer of children under the age of 5 worldwide, and while the definitive diagnosis of pneumonia typically is made with x-rays, only 5% of the world’s population has ready access to radiographic equipment. To address this problem, Sonavi Labs has introduced the Feelix line, a line of digital stethoscopes focused on abnormal lung sound detection. Compared to traditional, mechanical stethoscopes, the Feelix line offers three advantages: reduced sensitivity to placement of the sensing head, active noise cancellation, and automatic detection of lung sound abnormalities using an algorithm that incorporates machine learning. This new line of digital stethoscopes is appropriate for under-resourced regions of the world, for noisy clinics, and for medical professionals who wish to improve their ability to hear lung sounds. Using this line of digital stethoscopes is preferable to alternative methods that are under study, such as lung ultrasound, as its use is entirely noninvasive and its cost is a fraction of that of x-ray machines or ultrasound imagers.
Acoustic and dynamic characterization of wooden baseball bats
Authors: Pestka II Kenneth A. , Holmberg Derek E.
Published: April 2019

We will present the results of several experiments used to characterize the properties and performance of multiple baseball bats composed of four different species of wood including soft maple, hard maple, birch, and ash. Resonant ultrasound spectroscopy was used in an effort to obtain the complete orthotropic tensor of the different wood species. In addition, ultrasonic pulse-echo measurements and dynamic impulse time-of-flight measurements were performed to obtain longitudinal sound speeds, which in combination with bat geometry, mass, and density enabled the determination of the longitudinal Young’s moduli. Bat performance was then experimentally determined via a newly developed non-destructive impact method. The physical acoustic parameters that most significantly correlated with optimum bat performance will also be presented.
Photoacoustic harmony: Using musical concepts to study mixed gases through PA spectroscopy
Authors: Paratore Trevor , Park Han Jung
Published: April 2019

Photoacoustic Spectroscopy was applied to study the intensity of musical notes in harmony created by the photoacoustic signals of ethylene (C2H4) and sulfur hexafluoride (SF6) gases. Two CO2 lasers with a wavelength of 10.6 μm were modulated using two separate mechanical choppers. It was observed that musical notes with a frequency approximately that of the fundamental frequency of the resonator had higher intensity peaks than those further away. To equilibrate the intensities of these notes for fuller tones in the musical chords of interest, a second resonator, sulfur hexafluoride, having vastly different resonance properties from ethylene, was added to the gas cell. It was observed that this only moderately affected the outcome for the overall tone of the chords of interest. However, as expected, sulfur hexafluoride offered a more dynamic range of tones due to its large variance in resonance frequency with concentration.
High temperature dependent elastic properties of single crystalline SnSe
Authors: Karunarathne Ashoka , Gladden Josh R. , Priyadarshan Gautam
Published: April 2019

In recent years, single crystalline SnSe has been widely studied as a thermoelectric material which exhibits a high thermoelectric figure of merit (ZT ~ 2.6 at T > 900 K). The efficiency has been enhanced due to the significantly low thermal conductivity, arising from the strong lattice anharmonicity of the layered orthorhombic crystal structure. A study of the thermo-elastic properties of single crystalline SnSe is essential to gain a better understanding of the lattice anharmonicity and the low thermal conductivity. The highly anisotropic orthorhombic crystal structure of SnSe results in nine independent elastic constants. This work seeks to investigate the temperature dependent elastic constants of single crystalline SnSe, using resonant ultrasound spectroscopic (RUS). Here, we report the experimentally observed elastic constants and their variation at elevated temperature from room temperature to ~775 K. The temperature dependent elastic and thermal properties have been derived from the elastic constants and compared to independent heat capacity data.
Nonlinear resonant ultrasound spectroscopy using electromagnetic excitation
Authors: Gregg Joshua F. , Anderson Brian E.
Published: April 2019

Nonlinear resonant ultrasound spectroscopy (NRUS) is a method that can be used for detecting microcracks in structures. NRUS detects shifts in resonance frequencies versus excitation amplitude. Excitation of a sample is typically done with a piezoelectric transducer. Here, the application of an electromagnetic excitation is explored as an alternative for NRUS excitation. It involves gluing a coil of wire onto the end of a rod sample and placing it in a magnetic field. By controlling which part of the coil is in the strongest part of the magnetic field, the principle direction of the driven oscillations in the rod can be controlled. This method allows selective excitation of longitudinal, torsional, and bending vibrations, and the measurement of the nonlinear properties of the sample for each type of vibration is therefore possible. Both a piezoelectric transducer and electromagnetic excitation are used to measure the nonlinear elastic parameters of a Berea sandstone rod. The effects of heating of the sample and slow dynamics are explored and compared with each type of excitation. The purpose of this presentation is to illustrate the usefulness of the electromagnetic method and outline its differences from the piezoelectric method.
The acoustic effects of emphatic and pharyngeal consonants on adjacent vowels
Authors: Faircloth Laura R.
Published: April 2019

Emphatic consonants in Arabic are coronal obstruents with a debated secondary articulation, contrasting with plain coronals and affecting adjacent vowels (Watson, 2007). The secondary articulation has been claimed to be pharyngeal, so pharyngeals may affect vowels similarly. Eight speakers of Palestinian Arabic recorded words with /a:/, /i:/, or /u:/ following plain /s/, empathic /sʕ/, or pharyngeal /ħ/. The effects of plain and emphatic consonants on /a:/ have been studied, but other vowels may be affected differently. The CoG of /sʕ/ was lower than /s/, differing from previous studies (Card, 1983). F1 and F2 measurements from the onset, midpoint, and offset of the vowel showed the extent of emphatic effects. F2 in /a:/ and /i:/ and F1 in /a:/ and /u:/ adjacent to /sʕ/ were lower than adjacent to /s/ or /ħ/. Both suggest a backed and raised tongue in emphatics. F1 was only higher adjacent to /ħ/ at the onset, while emphatics affected the entire time course. Pharyngeal /ħ/ caused typical coarticulation, while the longer effects of emphatic /sʕ/ suggest a phonological process. The differences between emphatic and pharyngeal consonants also suggest that emphatic consonants in this dialect are produced with uvular constriction, not pharyngeal as has been claimed.
A kinematic investigation of coarticulation resistance in Modern Greek
Authors: Doli Evdoxia , Katz William F.
Published: April 2019

In order to examine the coarticulation resistance hypothesis (CRH) this study investigated patterns of CV and C1C2V overlap in consonant clusters and matching singletons in Greek, including five places of articulation in C2V position (bilabials, labiodentals, interdentals, alveolars, and velars). Stimuli were recorded from three talkers producing eight repetitions of each item, embedded in a carrier phrase. Kinematic and acoustic data were acquired with an electromagnetic articulography (EMA) system. Temporal measures were obtained by determining timing lags for both singletons and clusters, while spatial measures were found by calculating the Euclidean Distance (ED) of the tongue back sensor from the C2V velocity peak to that of the following vowel, for both singletons and clusters. Logarithmic ED ratios for each stimulus triplet (e.g., “ba”-“la”-“bla”) were then computed to test whether C2V allows C1V to exert coarticulatory influence on the vowel. Preliminary findings from both the temporal and spatial analyses suggest pronounced differences in complex versus simple syllable organization as a function of C2V place of articulation. The extent to which these results support the CRH will be further discussed.
Acoustic and articulatory investigation of the Mauritian vowel inventory
Authors: Myers Samantha , Henri Fabiola , Berkson Kelly
Published: April 2019

While there have been a decent amount of morphosyntactic and sociolinguistic studies on Mauritian, a “French-based” creole spoken by most of the population of Mauritius (e.g., Baker, 1972; Alleesaib, 2012; Henri, 2010; Miller, 2015; Syea, 2013), phonetic or phonological description on the language hardly exists. Pudaruth (1993) proposes a phoneme inventory consisting of 19 consonants and 8 vowels, intuitively noting that rhotics preceding vowels are weakened, almost unpronounced. In the present work, we empirically investigate the vowel inventory of Mauritian using acoustic and articulatory data. In addition to presenting basic acoustic measures (e.g., vowel spaces), we note the presence of a rhotic, and report acoustic measures which suggest strong variation between the orthographic “a” that precedes “r” and that which precedes all other written consonants. Ultrasound imaging confirms that the pre-rhotic “a” differs from other “a"s articulatorily.
Transfer in speech motor learning: The role of voicing
Authors: Cheng Hung-Shao , Buchwald Adam
Published: April 2019

Previous studies have demonstrated that American English speakers can improve their production of phonotactically illegal onset clusters (e.g., DBEEGO) after structured practice. However, the nature of what is learned remains incompletely understood. We use a transfer paradigm to address this question by examining performance on trained and untrained novel consonant sequences. In particular, we investigated whether the differences between voiced and voiceless stop-stop clusters (e.g., /gd/ vs. /kt/) influences transfer of learning, hypothesizing that the voiced clusters involve more complex motor control. Forty native speakers of American English practiced nonwords beginning with either voiced (/gd/, /db/, /gb/) or voiceless (/kt/, /kp/, /tp/) stop-stop onset clusters. All participants were tested on both types of clusters at baseline (prior to practice) and in two retention sessions (20 minutes (R1) and 2 days (R2) after practice). Blinded coders rated cluster accuracy based on presence of a vowel in the acoustics. Preliminary results (n = 10) indicate a trend of bi-directional transfer, with participants in both practice conditions exhibiting improved accuracy for both trained and untrained clusters.
Relative influences of information structure and utterance-final position on the prosodic implementation of nuclear pitch accents
Authors: Chodroff Eleanor , Cole Jennifer
Published: April 2019

The phonological and phonetic realization of a nuclear pitch accent has been claimed to reflect aspects of its information structure (IS). As the rightmost accented word in an intonational phrase, the nuclear pitch accent often co-occurs with utterance-final position, which in American English, is often cued by prosodic means such as creaky voice and domain-final lengthening. The present study investigated the relative influence of IS and utterance-final position on the prosodic implementation of words in nuclear position. The IS of an object noun phrase occurring in nuclear position was manipulated to be given, accessible, new, or contrastive relative to a parallel object noun in the preceding sentence. The critical object noun occurred in utterance-final position in experiment 1 and in non-final position and preceding a semantically vacuous syntactic phrase in experiment 2 (e.g., “that was there,” “for it"). Given that contrastive information significantly influenced the prosodic implementation of the object noun in both experiments with respective reduction and enhancement effects, but utterance-final position nevertheless regulated the particular phonetic instantiation. While IS modulated the degree of creakiness, duration, and intensity in final position, IS conditions in non-final nuclear position modulated the type of f0 contour and duration.
A waveform-based convolutional neural net for source range and ocean environment classification
Authors: Van Komen David F. , Neilsen Tracianne B. , Knobles David P. , Badiey Mohsen
Published: April 2019

Neural networks learn features that are useful for classification directly from a source, such as a recorded signal, which removes the need for feature extraction or domain transformations necessary in other machine learning algorithms. To take advantage of these benefits and have a finer temporal resolution than a spectrogram, we built a one-dimensional convolutional neural network to classify source range and ocean environment from a received signal. The neural network was trained on simulated signals generated in different environments (sandy, muddy, or mixed-layer sediment layers) for several range classes. We found significant potential in a neural network of this type, given a large amount of varied training samples for the network to learn important features to make range and environment predictions. This type of network provides an alternative for frequency-domain learning and is potentially useful for impulsive sources. Benefits of using a time-domain envelope are also explored. Success in the time domain also reduces the computational requirements of conversion to frequency domain and increases the temporal resolution, which might be beneficial for real-time applications. [Work supported by the Office of Naval Research.]