bluuebunny/crossref_metadata_2025 huggingface dataset:
Pupil-associated states modulate excitability but not stimulus selectivity in primary auditory cortex
Authors: Schwartz Zachary P. , Buran Brad N. , David Stephen V.
Published: November 2019

Recent research indicates that luminance-independent fluctuations in pupil size predict variability in spontaneous and evoked activity of single neurons in auditory and visual cortex. These findings suggest that pupil is an indicator of large-scale changes in arousal state that affect sensory processing. It is not known whether pupil-related state also influences the selectivity of auditory neurons. We recorded pupil size and single-unit spiking activity in the primary auditory cortex (A1) of ferrets during presentation of vocalizations and tone stimuli. Neurons showed a systematic increase in both spontaneous and sound-evoked activity when pupil was large, as well as a decrease in trial-to-trial variability. Relationships between pupil size and firing rate were non-monotonic in some cells. In most neurons, several measurements of tuning, including acoustic threshold, spectral bandwidth, and best frequency, remained stable across large changes in pupil size. Across the population, however, there was a small but significant decrease in acoustic threshold when pupil was dilated. In some recordings, we observed rapid, saccade-like eye movements during sustained pupil constriction, which may indicate episodes of rapid eye movement sleep. Including the presence of this state as a separate variable in a regression model of neural variability accounted for some, but not all, of the variability associated with changes in pupil size.
Polyphonic pitch perception in cochlear implant users
Authors: Camarena Andres , Goldsworthy Raymond L.
Published: November 2019

Cochlear implant (CI) devices take advantage of the tonotopic organization of the auditory nerve to provide moderate speech recognition. While commercial place-pitch strategies are sufficient for speech comprehension in quiet conditions, CI users struggle to detect multiple, simultaneous sources of pitch. In a polyphonic pitch-trajectory task, two streams (low and high pitch) are presented simultaneously. Participants perform a 1-interval-4-alternative forced-choice procedure to identify which stream changed in pitch and whether it went higher or lower in pitch (low-lower/low-higher/high-lower/high-higher). The low and high streams are high-rate pulsetrains modulated at 110 Hz and 220 Hz, respectively. The stimulus is 1 s in duration and the target stream contains an ascending or descending modulation-frequency sweep over the last 200 ms. The low stream will be presented to the most apical electrode and the high stream presented to electrode separations of 0, 2, 4, and 8. Preliminary results indicate that CI users perform better on the electrode psychophysical tasks than on acoustic variations. Additionally, performance is improved with sharper temporal envelopes. These results suggest that CI users are able to perceive polyphonic pitch and that resolution is limited by how temporal information is conveyed by clinical devices.
Impact of airfoil design uncertainty on the prediction of gust response
Authors: Walters Gage S. , Wixom Andrew S. , Martinelli Sheri , Berger Zachary P. , Krane Michael H. , Hanford Amanda , Lysak Peter
Published: November 2019

Unsteady lifting forces acting on an airfoil in turbulent flow can be an important source of vibration and noise in many applications. Models have been previously developed for predicting the unsteady lift forces that account for the design and shape of the airfoil, in particular showing that leading-edge thickness, camber, and angle of attack can create large differences in the high-frequency decay of the unsteady lift force. Small changes in these design parameters can have a profound effect on the response of the airfoil that can lead to increased noise and vibration levels. This study examines the variability of the unsteady lift due to uncertainty in such parameters using an uncertainty quantification technique known as generalized polynomial chaos. Probability distributions are assumed for each of the input parameters in order to calculate the overall stochastic behavior of the response as well as its sensitivity to each input. The resulting predictions are compared against experimental measurements.
Effects of L1 on the voicing of intervocalic voiceless stops and its relation with L2 proficiency
Authors: Jeon Ji-Hyun , Yoo Jiyun , Lee Seok-Chae
Published: November 2019

This study investigates the correlation between the proficiency of L2 learners of English and the degree of L1 Korean intervocalic voicing rule transfer on the English intervocalic voiceless stop production by Korean English learners. Korean has a phonological rule that voiceless stops become voiced between vowels (Korean intervocalic voicing rule) but this rule does not apply in English. The aforementioned difference between the phonological rule of the two languages makes it possible to predict that Korean learners with lower L2 proficiency might produce English intervocalic voiceless stops with higher degree of voicing than the learners with higher L2 proficiency. The speech data of Korean L2 learners of English is extracted from GenieSpeeCor, rated and categorized English speech corpus of Korean L2 learners of English production, and the value of intensity drop and closure duration were used as acoustic cues for voicing difference. Alveolar stop is excluded from the data analysis because the flapped /t/ sound is difficult to distinguish from the voiced sound. As a result of the current study, when it comes to the closure duration as an acoustic cue, there was no meaningful statistical relation between learners' L2 proficiency and the degree of intervocalic stops voicing. However, in terms of the intensity drop learners with the highest L2 proficiency showed a lower degree of voicing than the learners with middle and lowest proficiency.
Non-native English speakers’ adaptation to native English speaker’s speech
Authors: Lee Dae-yong , Baese-Berk Melissa M.
Published: November 2019

Previous studies have shown that listeners are able to quickly adapt to unfamiliar speech (e.g., regional-accented, foreign-accented, or time-compressed speech). While listeners initially have difficulty understanding unfamiliar speech, they are able to improve their ability to understand speech in a short period of time. Prior studies that examined adaptation to unfamiliar speech mostly focused on adaptation by native listeners, and it is less clear whether non-native listeners are able to adapt to native speech. This study aims to examine whether non-native speakers of English adapt talker-specifically to native English speech. Further, this study also examines, if non-native English speakers do adapt to native English speech, whether the intelligibility of utterances affects the adaptation. In the present study, non-native English speakers listen to English sentences read by native English speakers and determine whether the last word they heard matches the word on the screen. Response time is measured to examine whether non-native English speakers adapted to native English speaker’s speech and whether the intelligibility of speech interacts with the adaptation. The results of the study will provide a better understanding of non-native English speakers’ adaptation to native English speech and help improve the efficiency of conversations between native and non-native speakers.
A new auditory image for social media: Moving towards correlation of spectrographic analysis and interpretation with audience perception
Authors: Nguyen Nguyen Le Thanh , Lee Hyunhwan , Johnson Joseph , Ogihara Mitsunori , Ren Gang , Beauchamp James W.
Published: November 2019

Spectrogram and other time-frequency analysis methods transfer an audio file into an auditory image. When signal processing-based analysis and interpretation is performed on these auditory images instead of an audio signal, spectrographic analyses can identify interesting patterns that focus on very different aspects of the signal compared to an audio-based analysis. To facilitate an auditory image-based study, a quantitative analysis and interpretation framework is implemented for exploring the spectrographic images in multiple time and frequency scales and for automatically identifying image features that are relevant to human auditory perception. This analysis framework is applied to two social media datasets: (1) soundtracks from video commercials and “hit” music excerpts from social media platforms, and (2) soundtracks from television and film. Analysis results from social media are also compared with audience subjective evaluations to validate the perceptual relevance of the identified spectrographic patterns.
Observation and interpretation of recorded long-range, underwater acoustic signal propagation related to the search of the Argentine submarine ARA San Juan
Authors: Nielsen Peter L. , Zampolli Mario , Le Bras Ronan , Haralabus Georgios
Published: November 2019

In 2017, a signal from an impulse-like event of unknown origin (November) and from a successive controlled experiment in the same area involving the detonation of a depth charge (December), were received at the CTBT IMS hydrophone stations HA10 (Ascension Island, Atlantic Ocean) and HA04 (Crozet Islands, southern Indian Ocean) at ranges greater than 6000 km. The signals propagated through different deep underwater environments along geodesic paths from the sources to the hydrophone stations. The impact of these different environments is clearly observed in the recorded signals, in particular at HA04 as strong time dispersion and low-pass filtering compared to the HA10 data. An interpretation of the signal characteristics is performed by two-dimensional propagation modelling of full time-series including spatially dependent oceanographic database information. Range-dependent bathymetry and typical warm water propagation apply towards HA10, while polar-type conditions with sea-ice extent close to Antarctica are included in the computations at HA04. An acoustic precursor to the main arrival observed at HA04 suggests that the signal partly couples into the ice sheet and partly propagates under the ice sheet. The modelling results broadly agree with observed features and point to the importance of adapting detection and classification algorithms to specific propagation paths.
Three music facility makeovers in Arizona
Authors: Conant David A. , Shankar Arjun K. , Blaine Taylor L.
Published: November 2019

Considerable prior experience at higher education music campuses in Flagstaff, Chandler and Mesa, Arizona led to our engagement in substantial repurposing and renovation of their rehearsal, recording, practice, and performance facilities. Specific challenges due to existing mechanical system noise, poor sound isolation, and overall room-acoustics issues are discussed as well as their solutions and measured data upon completion.
Sound isolation among music teaching studios with glass curtainwall system
Authors: Schlaseman Steven
Published: November 2019

The acoustic success of music teaching studios is largely dependent on their sound isolation from others. Often these spaces are aligned along exterior walls for natural light and there is an architectural desire to connect them together with lightweight glass curtainwall systems. Sound transfer which flanks through shared curtainwalls and bypasses primary demising construction is a well-documented issue. During the design of the Tianjin Juilliard School in China, Jaffe Holden evaluated options to improve sound isolation for this condition while maintaining the continuous curtainwall aesthetic. This paper discuss the design considerations and the custom sound isolation tests that were performed to analyze and address this issue.
Tanglewood Learning Institute Linde Center for Music and Learning
Authors: Myers Joseph W. , Corry Brian , Hunt Kaitlyn
Published: November 2019

Since 1940 Tanglewood, the summer home of the Boston Symphony Orchestra in Lenox, Massachusetts, has operated the Tanglewood Music Center (TMC), a summer music academy where students can study with world class musicians. In 2019 Tanglewood added a new program, the Tanglewood Learning Institute (TLI), offering music lovers access to rehearsals, lectures, master classes and recitals. TLI will use a new facility, the Linde Center for Music and Learning, designed by Kirkegaard Associates and William Rawn Associates to complement the nearby 1100-seat Ozawa Concert Hall, designed in the 1990s by the same firms. The Linde Center includes three flat-floor rehearsal rooms, sized at 800 sf, 1,600 sf, and 4000 sf, offering rehearsal space to TMC students during the week, and rehearsal, recital, lecture, and banqueting space for TLI patrons on weekends. The Linde Center is air conditioned, but in keeping with the Tanglewood ethos operable walls and windows allow each of the three rooms to operate with natural ventilation, a challenge for room acoustics and sound isolation. The three spaces share a common architectural language and acoustical approach, but the details of their acoustic designs, AV systems and adjustable absorption respond to the size of the room and the differences in how often they see a particular use.
Geoacoustic inversion the Buckingham way
Authors: Chapman N. Ross
Published: November 2019

This paper examines the impact of Mike’s research on geoacoustic inversion for characterization of sea bed sediments. First is his paper in 1987 that reported the use of vertical coherence of ambient ocean noise for estimating critical angles of sea bed sediment. Apart from the novel use of ambient noise as a sound source, his work opened the idea to make use of information about the ocean bottom contained in spatial phase relationships in vertical hydrophone array data. The practice was quickly adapted and widely applied as matched field inversion. However, the inversions were generally carried out using visco-elastic theory of sound propagation, an approach that is not the most appropriate for applications with porous sediment material. Mike’s next contribution addressed this issue in his series of papers starting around 1997 on the grain-shearing and viscous grain-shearing models of sound propagation in porous media. His theory provided a physical basis for the model parameters that are used to describe the interaction of sound with porous sediment media in geoacoustic inversions. Recent examples are shown that indicate how these innovations have become standard practice in geoacoustic inversions.
The analytical approach of Mike Buckingham
Authors: Deane Grant B.
Published: November 2019

Mike Buckingham’s contributions to underwater acoustics and acoustical oceanography span a broad range of topics, from field expeditions to measure Arctic ambient noise in the marginal ice zone to a complete model for propagation and attenuation in marine sediments. The hallmark of Mike’s work is the formulation of elegant analytical solutions to canonical problems, providing physical insight. I will attempt to illustrate Mike’s approach with examples from his work and illustrations of how it has motivated and influenced future approaches.
Some reflections on Buckingham’s viscous grain shearing model
Authors: Holland Charles W. , Dettmer Jan , Dosso Stan E.
Published: November 2019

Sediment geoacoustic properties are of considerable interest for commercial, industrial, and naval applications. In order to make geoacoustic inferences from acoustic data, the practitioner must choose a sediment acoustics model. The ‘Hamilton model’ is the most common, which assumes a frequency-independent sound speed, density, and an attenuation varying linearly with frequency, f1. Buckingham’s Viscous Grain Shearing (VGS) model offers a practical alternative with important benefits. For example, since it obeys causality, it provides fundamental bounds to the parameter space that the Hamilton model does not. Furthermore, if the acoustic data are sufficiently informative, the model provides insight into the frequency dependence of sound speed and attenuation. The central physics in VGS are expressed in high-level (material impulse response) functions, which consider both viscous and friction loss mechanisms and lead to attenuation varying between f1/2 to f1 to f2. Geoacoustic inference from seabed reflection measurements using the VGS model provides insight into the frequency dependence of naturally occurring marine sediments, i.e., admixtures of clay, silt, sand. At present, the VGS model is likely the most general (causal) sediment acoustics model, i.e., can reasonably treat the broadest range of sediment fabrics. [Research supported by the ONR Ocean Acoustics Program.]
Grain shearing models and relevance beyond sediment acoustics
Authors: Holm Sverre
Published: November 2019

The grain shearing (GS) and viscous grain shearing (VGS) models for saturated, unconsolidated marine sediments fit well to real data. But the models have much further relevance. The inherent convolution is in fact the definition of a non-integer derivative. Therefore, the GS theory is exactly described by the fractional diffusion-wave equation for shear waves and the fractional Kelvin-Voigt wave equation for the compressional mode. Both have been studied extensively in fractional calculus [Pandey and Holm, “Connecting the grain-shearing mechanism of wave propagation in marine sediments to fractional order wave equations,” JASA (2016)]. The GS theory demonstrates that fractional derivatives arise naturally from physical processes and thus are more than just clever mathematics. These derivatives appear in the relaxation modulus, the stress response to a strain step, of the GS process. The variation in time of the viscosity makes it a time variant non-Newtonian process. But when strain and stress change roles, a surprising result appears. The creep response is the Lomnitz law, an empirically defined logarithmic relationship for such diverse materials as igneous rocks and wood [Pandey and Holm, “Linking the fractional derivative and the Lomnitz…,” Phys. Rev. E (2016)]. In the VGS model, the power-law response is exponentially tempered. The relaxation modulus is then that of the Cole-Davidson model, known from dielectric materials. This relationship has yet to be explored [Holm, Waves with Power-Law Attenuation (Springer, 2019), Chap. 8].
Nonlinear wave propagation in media with attenuation and dispersion modeled using a superposition of relaxation mechanisms
Authors: Archer Branch T. , Cormack John M. , Hamilton Mark F.
Published: November 2019

Michael Buckingham has long held interest in modeling wave propagation in media with nontraditional attenuation and dispersion, especially unconsolidated marine sediments exhibiting power-law attenuation [Buckingham, J. Acoust. Soc. Am. 138, 2871 (2015)]. The present authors have examined the implications of power-law attenuation and single relaxation mechanisms for modeling nonlinear propagation of compressional and shear waves [Cormack and Hamilton, Wave Motion 85, 13 (2019)]. Reported here are results for media that are modeled using multiple relaxation mechanisms. Below the lowest relaxation frequency, attenuation increases as frequency squared, and above the highest relaxation frequency, attenuation is constant. In between, the superposition may be tailored to approximate power-law attenuation that increases in proportion to frequency raised to an exponent between 0 and 2. Regardless of the source frequency and the number of relaxation mechanisms incorporated, there exists a critical source amplitude above which the mathematical model is incapable of offsetting nonlinear waveform distortion sufficiently to stabilize shock formation beyond the distance where an infinite gradient first appears in the waveform. Results are presented for birelaxing media corresponding to seawater and atmosphere, followed by models based on multiple relaxation mechanisms that approximate power-law attenuation over limited frequency ranges in sediment and tissue.
Ambient noise in coral reef environments
Authors: Freeman Simon E. , Freeman Lauren
Published: November 2019

Ambient noise in very shallow water is often dominated by sound from biological sources. In addition to their economic and aesthetic value, coral reef environments are of interest acoustically due to their persistently loud biological ambient noise levels, relatively high biomass, diversity of soniferous organisms, and their relatively unique spatial nature in which the receiver is often surrounded by large numbers of transient sources, each emitting relevant information. Stemming from work in the Buckingham lab, our investigation of these sounds and their connection with biological processes continues through both directional and point receivers. This talk will discuss how information contained in the transient aspects of these sound fields can reveal the nature of the sources and physical mechanisms behind the generation of their sounds, spatial distribution of benthic communities, dynamic interactions between organisms and changes in the environment arising from human impacts such as the removal of herbivorous fishes.
Michael Buckingham—Cosmologist
Authors: Lynch James
Published: November 2019

Before Mike Buckingham became and ocean acoustician, he had a rather different career path—that of a cosmologist trying to detect gravitational waves. In the late 1960s, physicist Joseph Weber published a paper in which he claimed to have measured Einstein’s gravitational waves. Efforts quickly ensued to either confirm or disprove Weber’s stunning claim—and Mike Buckingham was in the thick of these efforts. The story of Mike’s involvement traces a very interesting episode in the history of gravitational wave research. It also involves a fair bit of acoustics, as that was the technique used at that time (and is still pursued to some extent today). Perhaps most happily, this story explains how and why Mike Buckingham became an ocean acoustician, which is the ASA’s gain (though cosmology’s loss.)
Filtered delay multiply and sum beamforming in high frame-rate ultrasound imaging
Authors: Matrone Giulia , Ramalli Alessandro
Published: November 2019

Filtered Delay Multiply and Sum (F-DMAS) is an ultrasound beamforming technique derived from microwave imaging, which exploits the spatial autocorrelation of the receive aperture to improve the quality of images. Being based on the spatial coherence of backscattered echoes, it reconstructs a pulse-echo beam with lower sidelobes and a narrower main lobe as compared to standard Delay and Sum (DAS). Thanks to this, F-DMAS can be effectively employed in high frame-rate (HFR) ultrasound imaging, where higher acquisition rates come together with more artifacts, lower contrast and worse spatial resolution. This presentation will provide an overview of the most recent applications of F-DMAS in HFR imaging, e.g., with multi-line transmission and plane-wave techniques. Results of simulations, phantom experiments and in vivo scans, particularly of cardiac imaging, show that F-DMAS represents an effective solution to improve image quality, suppress artifacts and increase the frame-rate at the same time. Moreover, two alternative methods, developed starting from the F-DMAS formulation, will be shown as they further enhance the image quality in HFR imaging.
Passive elastography: Extracting mechanical properties of soft tissues from natural elastic waves
Authors: Catheline Stefan , Giammarinaro Bruno , Zorgani Ali , Zemzemi Chadi , Souchon Rémi , Rouvière Olivier
Published: November 2019

Clinical devices that give elastography imaging from a shear wave speed measurement within tissues uses controlled sources for elastic wave generation. It can be a mechanical vibrator for transient elastography and magnetic resonance elastography (MRE) or ultrasound radiation pressure for ARFI and shear wave elastography technique. Generally speaking, the main drawback of all these methods is the drop of efficiency for deep regions and obese patient. Delivering robust elastic waves in depth is an issue. We have proposed in the past a solution that avoid the problem of shear wave penetration using active sources. It consists in using natural shear waves that exist everywhere in living tissues. These natural shear wave are created thanks to heart beating, to pulse wave within arteries or to muscle activities. Since a few years now, we have been tracking natural shear waves in different soft tissues of the human body and we have not yet been disappointed. Using uncontrolled shear wave needs a change in the group velocity measurement paradigm. This approach is the so-called noise correlation technique developed in the field of seismology.
Using multiparametric ultrasound-based elastographic characterization for evaluation of renal transplants
Authors: Urban Matthew W. , Vasconcelos Luiz , Kijanka Piotr
Published: November 2019

Renal transplant is a long-term therapy for patients in end-stage renal disease. Renal transplant health is monitored using laboratory tests and renal biopsy. However, renal biopsy is invasive and has issues with sampling errors. Ultrasound-based shear wave elastography (SWE) is being evaluated in renal transplants to identify patients with early stages of interstitial fibrosis and inflammation. We are exploring the use of new image reconstruction approaches such as local phase velocity imaging (LPVI) to evaluate viscoelasticity in a cohort of 23 renal transplants. Additionally, from point SWE measurements we have compiled results from 97 patients and have used various machine learning approaches to differentiate patients without disease such as interstitial fibrosis, inflammation, or interstitial fibrosis with tubular atrophy (IFTA). The LPVI method provides two-dimensional maps of phase velocity and images of viscoelastic parameters after fitting to a rheological model. The machine learning approaches combine multiple elastographic parameters to provide differentiation with high sensitivity, specificity, and accuracy (∼ 85%–90%). These approaches could have substantial benefit for patients for identifying early disease in renal transplants that my precede changes in laboratory test results.
Ultrasonic evaluation of bone health in patients
Authors: Fatemi Mostafa , Alizad Azra
Published: November 2019

Noninvasive and quantitative methods for evaluation of bone health are of interest in clinical practice. Two areas of particular interest include evaluation of bone fracture healing and assessment of osteoporosis. Determination of bone healing time impacts patient health and the associated economic factors. Furthermore, assessment of bone quality in patients at risk for osteoporosis/osteopenia can benefit a large number of patients in the upper age group. Here, we present a quantitative method for the evaluation of bone integrity and quality. This method is based on analyzing the acoustic response of bone to stimulation provided by the acoustic radiation force of ultrasound. Longitudinal studies for bone healing assessment were conducted on a group of patients with clavicle fracture. The contralateral intact bone was used as a control for each patient. Bone healing assessments were performed using mode decomposition. It was found that the healing process could be detected in 80% of fractured bones. A separate study was conducted to differentiate osteoporotic/osteopenic from normal bones. A total of 27 adult volunteers in two groups of healthy and those with osteopenia/osteoporosis were tested. Results of the test on tibia showed that osteoporosis/osteopenia bones could be differentiated from the healthy ones (<2 × 10-5).
Comparison of deep learning and classical breast mass classification methods in ultrasound
Authors: Byra Michal , Galperin Michael , Ojeda-Fournier Haydee , Olson Linda , O'Boyle Mary , Comstock Christopher , Andre Michael P.
Published: November 2019

We developed breast mass classification methods based on deep convolutional neural networks (CNNs) and morphological features (MF), then compared those to assessment of four experienced radiologists employing BI-RADS protocol. The classification models were developed based on 882 clinical ultrasound B-mode images of masses with confirmed findings and regions of interest indicating mass areas. Various transfer learning techniques, including fine-tuning of a pre-trained CNN, were investigated to develop deep learning models. A matching layer technique was applied to convert gray-scale images to red, green, blue to efficiently utilize discrimination of the pre-trained model. For the classical approach, we calculated MF related to breast mass shape (e.g., height-width ratio, circularity) and then trained binary classifiers. We additionally evaluated both approaches using two publicly available US datasets. Several statistical measures (area under the receiver operating curve [AUC], sensitivity and specificity) were used to assess the classification performance on a test set of 150 cases. The matching layer significantly increased AUC from 0.895 to 0.936 while radiologists’ AUCs ranged from 0.806 to 0.882. This study shows both deep learning and classical models achieve high performance. When developed as a clinical tool, the methods examined in this study have potential to aid radiologists accurate breast mass classification with ultrasound.
Structural Acoustics and Vibration: Which came first, the sound or the vibration?
Authors: Koch Robert M.
Published: November 2019

Structural acoustics may be defined as a multidisciplinary coupled field of physics usually referring to the characterization of either (1) the sound power emitted by a vibrating structure subjected to external dynamic excitation or (2) the vibrational response of structures excited by incident sound fields or fluid excitation. The Structural Acoustics and Vibration (SAV) Technical Committee is a diverse group of scientists and engineers sharing a common interest and shared stewardship in the health and advancement of the SAV technical discipline. In addition to the fundamental scientific study of the underlying SAV physics which is important to all SAV practitioners, there is also interest on the practical real-world, application of the SAV science to predict, control, and potentially reduce the vibroacoustic response of given structural acoustic systems. This paper begins by providing a fundamental definition of the underlying physics governing the SAV technical discipline. The numerous categories and subdivisions within the general SAV area are then addressed, along with illustrations of the broad array of scientific and engineering real-world applications in the field. Following that, examples of interesting career options as well as exciting new research areas in SAV are presented. Finally, this paper concludes with information regarding the makeup, functioning, and administrative philosophy of the SAVTC.
Biomedical Acoustics: Breaking old barriers in science and medicine
Authors: Maruvada Subha
Published: November 2019

The Technical Committee on Biomedical Acoustics (BATC) is one of the most diverse groups in the Acoustical Society of America. BATC is comprised of scientists and engineers who study a wide range of biomedical applications using ultrasound from imaging fetuses to ablating fibroids and treating brain disorders. Diagnostic ultrasound has expanded to include exciting new techniques such as shear wave elastography and opto-acoustic imaging. Therapeutic ultrasound applications include physiotherapy, lithotripsy, as well as the treatment of tumors via thermal ablation, i.e., HITU, or mechanical ablation, i.e., histotripsy. The most recent developments in therapeutic ultrasound involve neuromodulation and transcranial magnetic resonance guided focused ultrasound for the treatment of various brain disorders, including essential tremor, neuropathic pain, and Parkinson’s disease. The ability to temporarily open the blood-brain barrier using focused ultrasound has been demonstrated in animals and, more recently, in humans. Opening of the blood-brain barrier could allow the transmission of drugs to treat brain diseases. Diagnostic and therapeutic ultrasound applications continue to advance the field of medicine and are integral to the advancement of both diagnosis and treatment of debilitating diseases.
Overview of Speech Communication Research
Authors: Polka Linda
Published: November 2019

Although speech communication is a fundamental part of our daily behavior, it is not yet well understood. Speech communication research examines how spoken language is produced, transmitted and perceived. This involves a number of different disciplines, from linguistics and experimental psychology to speech and hearing sciences, and electrical engineering. The field covers a wide range of physiological, psychological, acoustic, and linguistic phenomena. In this talk, I will provide a broad overview of the types of research that happen within our TC. I will highlight the advantages of participating in the ASA through examples that show how work in Speech Communication may inform or be informed by work in other technical areas within our society.
Debunking unusual false noise damage claims
Authors: Hale Marlund E.
Published: November 2019

We live in a society where noise seems to be everywhere and some of it is relatively loud, very annoying or even painful. In some cases we use noise to mask out noise, or we use ear plugs or we create quite spaces or “sound proof” rooms, just to get some peace and quiet. Nowadays, nearly everyone is aware of the annoyance or potential harm caused by other people’s noise. This has been a liability issue for employer’s and insurance companies. Laws, ordinances, regulations and standards (LORS) have been passed or otherwise put into place in an attempt to remedy excessive noise situations. Occupational hearing loss claims, violation fines, jail time and civil lawsuits have all taken place because of noise conflicts. This paper presents three examples where litigation was attempted for financial gain or to impose a heavy financial burden and force a business closure, when the plaintiffs enacted noise damage legal claims. Examples of noise from (1) a pick-up mounted railroad engine horn; (2) a very large rural private gun club with SWAT, law enforcement and military “Afghanistan-type” progressive urban and desert conflict scenarios; and (3) an EMT training class explosion simulation. Claims and outcomes are discussed.
“Super-efficient gradient estimation technique,” Recent advances in efficient adjoint sensitivity analysis and its application in metamaterial design
Authors: Kalantari Laleh S. , Bakr Mohamed , Ghassemi Marzyeh
Published: November 2019

Computer-aided design (CAD) tools in electromagnetics allow accurate modeling of the preferred responses. We can adjust a desired response by conducting an optimization algorithm. This requisite the gradient estimation of structures with respect to potentially N number of optimizable parameters. In conventional gradient estimation methods, the number of required simulations scales linearly with N. Adjoint variable method (AVM) is an extremely efficient sensitivity analysis method that estimates the gradients with respect to the all N parameters by conducting only 2 simulations, regardless of N. We have developed AVM method for gradient analysis of anisotropic and dispersive anisotropic structures. Then, we applied it in wideband inversely invisibility cloak design for 2-D and 3-D structures at optical and microwave frequency regions. In those examples, our algorithm accelerates the gradient estimation over 1400 and 12 500 times per iteration, respectively, compared to the conventional methods. This advanced optimization based metamaterial cloak design to 3-D arbitrary shape objects and optical frequency region which was not feasible before. For the next step, we are planning to extend this efficient gradient estimation algorithm to the state of the art machine learning techniques and recently introduced continuous neural networks such as neural ordinary differential equations (ODE-Net).
Optimization of one-dimensional Willis materials with hidden lumped elements
Authors: Mauck China M. , Muhlestein Michael B.
Published: November 2019

Willis coupling is a recently recognized material property that couples the pressure-strain and momentum-velocity equations and can lead to novel applications of metamaterials. We present an approach for optimizing the asymmetry factor (a non-dimensional measure of Willis coupling's effect on the specific acoustic impedance) in a metamaterial with lumped-element hidden degrees of freedom. The representative material element in the system we examine is a length of tube, which could be considered as a unit cell in a periodic system. Lumped-element features including side-branch resonators and membranes may be attached to the tube at various locations. We aim to determine optimal locations for each type of lumped-element feature, as well as optimal parameters in the design of the features themselves (e.g., for a resonator: volume, neck length, and neck cross-sectional surface area). An ideal design for a metamaterial exhibiting significant Willis coupling would result in a broadband non-negligible asymmetry factor.
A high-fidelity multi-channel portable platform for development of novel algorithms for assistive listening wearables
Authors: Pavlovic Chaslav , Kassayan Reza , Prakash S. R. , Kayser Hendrik , Hohmann Volker , Atamaniuk Andy
Published: November 2019

The NIDCD has funded a number of projects to develop portable signal processing tools that enable real-time processing of the acoustic environment. The overarching goal is to provide a large group of researchers with the means to efficiently develop and evaluate novel signal processing schemes, individualized fitting procedures, and technical solutions and services for hearing apparatus such as hearing aids and assistive listening devices. We report here on a development done in the SBIR Phase II Project R44DC016247. This project builds on the software being concurrently developed in R01DC015429 to provide a complete portable and wearable software-hardware master hearing aid device needed for development of new solutions for assisted hearing. We will present and demonstrate the portable platform, currently in the Beta launch, that consists of a Cortex A8 based processing unit and a codec set able to support hearing aid architecture of up to 6 microphones and 4 speakers. It is currently accompanied by a binaural 2-microphone BTE hearing aid set, but will also support different headset form-factors of our partners. Additionally it features stereo line in and line out connections. The device can be remotely controlled with a smart phone.
Open Master Hearing Aid (openMHA)—An integrated platform for hearing aid research
Authors: Kayser Hendrik , Herzke Tobias , Maanen Paul , Pavlovic Chaslav , Hohmann Volker
Published: November 2019

The project R01DC015429 “Open community platform for hearing aid algorithm research” provides a software platform for real-time, low-latency audio signal processing: the open Master Hearing Aid (openMHA). It contains a versatile set of basic and advanced methods for hearing aid processing, as well as tools and manuals enabling the design of own setups for algorithm development and evaluation. Documentation is provided for different user levels, in particular for audiologists, application engineers and algorithm designers. The software runs on various computer systems including lab setups and portable setups. Portable setups are of particular interest for the evaluation of new methods in real-word scenarios. In addition to standard off-the-shelf hardware, a portable, integrated research platform for openMHA is provided in conjunction with the SBIR project R44DC016247. This contribution introduces openMHA and discusses the usage and possible application scenarios of the portable openMHA setup in hearing research. The opportunity is given to try a smartphone-based self-fitting application for the portable openMHA, and to learn about the flexible configuration and remote control of openMHA running a typical hearing aid processing chain. Furthermore, a discussion and exchange of ideas on current challenges and future developments is offered.
Smartphone and algorithms: A platform for hearing study
Authors: Panahi Issa M. , Thibodeau Linda
Published: November 2019

Popular smartphones are portable devices with useful features such as powerful processor, microphones, speakers, low audio input/output delay, wire and wireless communication capability, graphical user interface (GUI) and easy-to-use touch screen. The smartphone features are improved every year. These features make smartphone a powerful stand-alone device for the development and real-time implementation of novel signal processing algorithms suitable for improving hearing study and hearing aid applications. In this paper, we present our smartphone-based platform and associated tools and documents for hearing study and hearing aid applications. An overview is given of the algorithms/apps developed to run on iOS and Android based smartphones in real time. Summary of the performance of developed algorithms/apps using smartphone is presented in comparison with other devices that are available in the market under different noisy conditions and low SNRs.
On mitigating acoustic feedback in hearing aids with frequency warping by all-pass networks
Authors: Lee Ching-Hua , Chen Kuan-Lin , Harris Fred , Rao Bhaskar D. , Garudadri Harinath
Published: November 2019

Acoustic feedback due to the acoustic coupling between the microphones and loudspeakers at high gains can cause the hearing aid system to become unstable. This instability results in brief “howling” artifacts as magnitude and phase conditions fulfill the Nyquist stability criterion (NSC). We present a novel approach that uses all-pass networks to perform nonlinear spectral mapping that we call “freping,” a portmanteau for frequency warping. In this contribution, we focus on spectral manipulations on top of adaptive feedback cancellation (AFC) to break NSC for improved feedback reduction. A real-time, multichannel realization is presented, which has individual control of the warping degree in each frequency band. Freping helps mitigate the NSC and thus leads to improved feedback control, while distortions due to freping are fairly benign based on informal subjective assessments. Our current findings indicate that improvements in terms of the perceptual evaluation of speech quality (PESQ) and the hearing-aid speech quality index (HASQI) can be achieved with freping for a basic AFC (PESQ: 2.56 to 3.52 and HASQI: 0.65 to 0.78) at medium amplification; and an advanced AFC (PESQ: 2.75 to 3.17 and HASQI: 0.66 to 0.73) at high amplification. Additional results will be included in the final presentation.
Application of transfer matrix method, Green's function, and variational technique to predict diffuse absorption with edge effect
Authors: Nguyen Duyen , Teagle-Hernandez Allen
Published: November 2019

Acoustic calculations utilizing the Transfer Matrix Method (TMM) occasionally underestimate the sound absorption performance of multi-layered porous material when compared to experimentally obtained data. This is particularly true when experimental data pertains to reverberant (Diffuse-Sabine) absorption. When there is a large impedance mismatch between the reverberant wall and the porous specimen, experimental data indicates Absorption Coefficients greater than 1, which defies the law of conservation of energy. It is hypothesized that the extra absorption is due to the diffraction of waves occurring at the edge of the tested materials, thus increasing the area where energy is absorbed. This contradiction of the law of energy is often referred to as the “edge effect”. This study aims in creating a tool to predict and further understand the edge effect phenomena within reverberation and anechoic rooms and to determine the true absorption performance of the multi-layered porous material by using the TMM, Green’s function, and the variational technique. A plate-foam system is used as a test bed; computation results are compared to experimental absorption data. The outcome of the research will support automobile, aerospace, and architectural companies in reaching sound and vibration targets required for new vehicle/building models.
Acoustic transients from the impact force excitation of beams and wind chimes
Authors: Stepanishen Peter
Published: November 2019

A time dependent modal based approach is presented to address the structural acoustic transients resulting from the impact excitation of a beam or wind chime. The normal velocity of the structural element is first expressed as a space-time modal expansion using the in-vacuo normal modes as basis functions. A convolution integral equation approach is presented to determine the time dependent modal velocities where fluid loading is included via the use of self and mutual modal radiation impulse responses which provide modal coupling. The modal radiation impedances and impulse responses are obtained from the associated radiation resistances via the use of Hilbert and Fourier transform relationships. Time-dependent dipole modal distributions along the beam or wind chime are then used to determine the pressure field using a convolution integral approach with the modal velocities and modal space-time impulse responses which are simply related to the in-vacuo modes . Numerical results are presented to illustrate interesting coincidence effects in the transient acoustic far field from beams and wind chimes.
Formation of the broadband biosonar beam of dolphins: Melon-focusing hypothesis not correct
Authors: Au Whitlow , Wei Chong
Published: November 2019

In 1974, Norris and Harvey measured the sound velocity profile of the melon of a just deceased bottlenose dolphin and found a low-velocity core in the melon with the velocity increasing towards the surface. This was the genesis of the “melon focusing” hypothesis in the formation of the biosonar beam. Aroyan solved the wave equation for a signal produced at the nasal plug using a finite difference approach and found that the skull was responsible for the biosonar beam. Aroyan’s results were never taken seriously and the notion that the melon was mainly responsible for the biosonar beam continues to this day. We used a finite element approach to solve the wave equation for a broadband signal generated at the phonic lips. CT scan data were used to provide a map of the acoustic impedance of the dolphin’s head and our results compared well with different measurements made around the dolphin’s head and in the far field. Our findings also showed that the skull and air sacs are the most influential structures in the formation of the biosonar beam and the melon was responsible for directing the axis of the beam. Our results should put to rest the “melon-focusing” hypothesis.
Signal processing for biological transients emitted by dolphins and snapping shrimp
Authors: Ferguson Brian G. , Ferguson Eric L.
Published: November 2019

In temperate and tropical waters, the dominant source of biological noise in shallow bays, harbors and inlets is snapping shrimp, which can adversely affect the performance of high-frequency sonar systems. The modified method for passive ranging by wavefront curvature enables the source position and source level of individual snaps to be measured in situ. The results are presented for a sequence of 1000 snaps. The principal habitat of the local snapping shrimp population coincides with a narrow wharf, which is 120 m in length. Next, this passive ranging method is used to localize free-ranging dolphins in their natural habitat. The peak-to-peak sound pressure levels of the biosonar pulses (clicks) emitted by Indo-Pacific dolphins (Tursiops aduncus) are measured for source ranges from 30 m to 300 m, even when the dolphins are echolocating at the same time. The waveforms and signal properties of the click signals are presented, along with their effectiveness for probing the shallow-water environment. The bistatic scattering impulse responses of the sea floor, sea surface and scatterers in the water volume are shown. Finally, consideration is given to the contexts in which snaps and clicks are made.