bluuebunny/crossref_metadata_2025 huggingface dataset:
A new hybrid method between equivalent source method and boundary element method for modeling diffraction
Authors: Roggerone Vincent , Guillermin Régine , Rakotonarivo Sandrine T.
Published: November 2021

The Equivalent Source Method (ESM) allows to model the acoustical radiation of an object with a set of monopole sources inside the object. This method efficiently describes acoustical radiation of an object with smooth surface, but is not performant for addressing diffraction induced by sharp edge. In this study, we use the simple source formulation to establish ESM as an integral formulation. In this form, ESM belong to the Boundary Element Method (BEM) family, with an implicit mesh. Therefore, we propose an alternative method similar to ESM with sources on the surface object, as the singularities can now be handled with the integral formulation. This new method is more performant than ESM for modeling diffraction, and is easier to implement than standard BEM based on Gauss Quadrature while it still takes advantage of the ESM implicit mesh. Comparisons of this hybrid method with ESM and standard BEM approaches show that the developed method is a good compromise between the two other approaches: the new method is more accurate than BEM, but less than ESM for a smooth object; while it is equivalent to BEM and more accurate than ESM for an edgy object. Work Funded by AMIDEX foundation.
A three-dimensional multi-grid staggered finite-difference time-domain method for underwater target acoustic scattering
Authors: Sabatini Roberto , Pailhas Yan , Urso Giorgio , Cristini Paul , Xenaki Angeliki , Tesei Alessandra
Published: November 2021

Solving the linearized equations of continuum mechanics to model the acoustic scattering of targets close to the seafloor is a challenging task. Among the traditional algorithms, staggered second-order finite-difference time-domain (FDTD) schemes combine simplicity and ease of implementation and parallelization, especially on modern GPUs. They have been successfully applied in two-dimensional configurations. Their major drawback is their inherent low resolution, due to their formal low order and the stair-step representation of the interfaces between media (e.g., target/water). To avoid excessive computational costs in three-dimensional configurations, while maintaining high numerical accuracy, we propose a FDTD multi-grid method. The mesh is refined locally near the interfaces, while a coarse grid is employed in homogeneous regions. In the fine grids, the aforesaid FDTD is employed, whereas, in the coarse grid, higher-order staggered schemes are used to compensate for the decrease in resolution due to the larger spacing. High-order interpolation allows matching the solutions at the grid interfaces. In this presentation, the performances of the new method on classical benchmark tests are analyzed and discussed. The numerical and computational capabilities are then illustrated by applying the proposed technique to the scattering of buried objects.
Implementation and analysis of high-performance cloud computing for underwater acoustic modeling applications
Authors: Higgins Alex , Siderius Martin
Published: November 2021

In the last few years advances in compute speeds have plateaued and multi/parallel processing (MPP) has been the way forward. With the advent of multiple processor cores packaged within a single microchip the architectures that were restricted to large servers has crossed over into consumer workstations. Now, more than ever, an understanding of how to maximize computational work is needed. The design and implementation of a Cloud based parallel-compute cluster for very large-scale processing of underwater acoustic models is presented. Ray-based, parabolic equation and wave number integration models were evaluated. This type of system allows for the creation of real-world sized solution sets which were previously prohibitive for most researchers. This is mainly due to their excessively long runtimes or being restricted to gated hardware, such as super-computer systems. Amazon Web Services is used as the underlying technologies for the creation of the Cloud based parallel-computer cluster, but the principles discussed are universal and may be applied to any MPP system. [Work supported by the Office of Naval Research.]
Dynamically orthogonal ray equations with adaptive reclustering
Authors: Charous Aaron , Humara Michael J. , Ali Wael H. , Bhabra Manmeet S. , Gupta Abhinav , Lermusiaux Pierre F.
Published: November 2021

The vast size of the ocean coupled with the Nyquist criterion often makes high-frequency ocean acoustics computationally intractable without approximation. A common approach is to employ ray theory to develop an approximate Green’s function for the acoustic wave equation. But due to the dynamic nature of ocean fields and the many sources of uncertainty in the temperature, salinity, density, sea surface, bathymetry, neither the sound speed nor the source and receiver locations are precisely known, and a single deterministic solution of the ray equations is often insufficient. In place of Monte Carlo simulations, we develop and numerically solve dynamically orthogonal ray equations to efficiently approximate solutions to the stochastic acoustic wave equation. The Lagrangian nature of the ray equations introduces a new computational challenge for reduced-order models; a naive approach requires realizations to be reconstructed at each time step. To remedy this, we employ a Taylor expansion of the sound speed around “mean rays” and propose a novel, adaptive algorithm to determine when the modes and coefficients of the reduced-order model must be reclustered and/or augmented to preserve accuracy. This offers a unique methodology for uncertainty quantification in the presence of non-Gaussian statistics which may be utilized in forward modeling as well as in acoustic inverse problems.
The effect of COVID-19 on underwater sound
Authors: Barclay David R.
Published: November 2021

The sounds of the turning machinery and propulsion systems from commercial ships are ubiquitous in the temperate deep ocean basins. The vertical structure of seawater temperature, salinity, and pressure conspire to create nearly lossless underwater propagation conditions at 10’s and 100’s of Hz, the frequency band where diesel engines and generators, cavitating propellers, and turning gearboxes produce their peak acoustic energy. In the shallow waters of the continental margins, the human use of the ocean for transport, fishing, recreation, and construction has led to increasing levels of anthropogenic noise over the last century. As the COVID-19 pandemic spread across the globe, the reduction of economic activity and marine traffic resulted in a decrease in underwater noise, with observations made at a number of underwater listening stations and autonomous recording devices across the ocean basins. These measurements, along with ship track data provided by the automated identification system (AIS) and trade and shipping statistics, improve our knowledge of the relationship between acoustic energy, the marine acoustic habitat, and the various human uses of the ocean.
COVID-19 effects on social isolation for older persons with sensory loss
Authors: Nelson Peggy , Wu Walter Yueh-Hsun , Oeding Kristi , Anderson Elizabeth , Teece Katherine , Legge Gordon
Published: November 2021

Social isolation and loneliness are significant risk factors for overall health, especially for older adults with vision or hearing impairment. This study was designed to understand the impact of the COVID-19 pandemic restrictions on the social /emotional wellbeing in adults with sensory impairment. Three groups of older adults -- vision loss (VL, N = 13), hearing loss (HL, N = 12 with cochlear implants and N = 12 with hearing aids), and controls (CTL, N = 18) -- were recruited from the Twin Cities community. They were interviewed at 6-week intervals from April 2020 to July 2021 concerning their wellbeing and social isolation. Overall, results show the widespread impact of the pandemic on social interactions and emotional wellbeing of older adults with sensory loss. All three groups had worse scores on the patient health questionnaire (PHQ-9) after the start of the pandemic. Older people with visual impairments were especially vulnerable to changes that led to a loss of independence. Although facial coverings impaired speech intelligibility for older people with hearing loss, the quieter acoustic environment during stay-at-home restrictions of gatherings may have mediated the negative effects. Results highlight unique factors that have affected older persons with sensory loss.
A computational method to determine transition times for soprano and bass clarinet players
Authors: Coyle Whitney L. , Wong Evangelina Y. , Gabriel Jack D. , Kaplan Connor N.
Published: November 2021

This work defines transition times between articulated notes for reed instruments such as clarinets and bass clarinets. To determine these transition times, analysis of measurements of musician mouthpiece pressure, measured using sensor-equipped mouthpieces made especially for the clarinet and bass clarinet is required. The transition time (△T) can then be compared in different musical contexts (dynamics, tempos, etc.), playing regimes, and between various players. The data collection method and metric definition will be described, and results from different playing situations will be offered.
Finite element modeling of guitar top plates
Authors: Caisse Joely , Hoffman Kurt R.
Published: November 2021

Here we describe the results of finite element method modeling of the resonant vibrations of a guitar top plate in various stages of construction using COMSOL. These models were completed in parallel with electronic speckle pattern interferometry ESPI measurements on three different top plates made of Engleman spruce purchased from Stewmac. The modeling was first set up for a thin piece of wood in a rectangular shape. Subsequent modeling was done at each step as the bode shape was cut, then a tone hold cut, and finally bracing was added. Care was taken to rotate the stiffness matrices for the braces in the model. Normal mode eigenfrequencies and mode shapes were calculated at each step in the fabrication process. Good agreement between the model and the measured data was obtained at low frequencies, but the model deviated from the measured results at higher frequencies.
Finite element simulations of free reed instrument operation
Authors: Kaufinger Philip , Wynne Liam , Cottingham James P.
Published: November 2021

To facilitate research into the acoustical properties of free reed instruments, there is a need for a quick and inexpensive way to prototype new geometries. It is here that a computational model with easily adjustable parameters offers a substantial advantage over an experimental apparatus if it can sufficiently resolve the essential acoustic features. Simulations using the finite element method have been utilized to solve the fluid dynamics, pressure acoustics, structural mechanics, and the multi-physics couplings underpinning various free reed systems. These phenomena include attack transients and frequency-pressure dependence of Western free reeds, fluid-structure interaction of turbulent airflow in an Asian free reed, effects of air compressibility on reed vibration, and the acoustic impedance of a reed-driven khaen pipe. Results consistent with experimental and analytical models were obtained and methods of optimizing the computational cost while maintaining realism are proposed. The models fail, however, to capture the essential feature of free reed sound production via the periodic interruption of airflow through the reed plate. Ways for future research to achieve this benchmark are suggested. [Research supported by National Science Foundation, Grant NSF-REU-1950337.]
On cataloguing the possible waveforms for impulse propagation along ground to ground thermospheric paths
Authors: Blom Philip S. , Waxler Roger M.
Published: November 2021

Infrasound propagation in the thermosphere is characterized by very low mean density, a very steep mean temperature gradient, and tidal winds. The steep temperature gradient means that there is always a thermospheric duct and this always provides ground to ground propagation paths that pass through the thermosphere. These paths are modulated by the atmospheric tides, while the very low density in the thermosphere causes severe attenuation and non-linear distortion. For an impulsive signal initially in the form of an N-like wave, such as the signal produced by a large explosion, non-linear propagation effects cause the positive pressure phases to propagate more rapidly than the negative pressure phases, in turn causing the duration of the impulse to increase. This effect can be quite significant in the thermosphere and continues until a caustic is encountered transforming the N-wave into a U-wave. The severe attenuation causes the high frequency components of the signal to attenuate resulting in a long period and fairly clean waveform that propagates back to the ground. The combination of steep temperature gradient and atmospheric tides produce a canonical thermospheric propagation environment with a diurnal cycle. In this presentation, it is shown that non-linear ray theory (weak shock theory) can be used to catalogue the waveform shapes of ground returns from explosive signals traveling along thermospheric paths. Qualitative comparisons to observed thermospheric returns are made.
Infrasound sound source localization for early tsunami detection
Authors: Arifianto Dhany , Ihsannur Haris , Eka Rini Bernadeta N. , Radityo Muhammad R.
Published: November 2021

Early detection of tsunami needed for sufficient evacuation time, which the existing method using buoy can not accommodate. In this report, we investigated low-frequency signal (infrasound) as a cue for tsunami detection. We used Bayesian infrasound source localization (BISL) method for predicting events and direction of the tsunami based on prior data. The method consists of three processes such as detection, association, and localization. All processes are done to infrasound data that are recorded from the microphone array. The recorded infrasound data at Minahasa, Indonesia used for evaluating the proposed method. The result indicates that BISL can predict latitude, longitude, and incident time of the tsunami based on the true value of the real tsunami event.
Threshold and the consultation process
Authors: Castañon Angel
Published: November 2021

Here I had the opportunity to take part in the Acoustical Society of America’s (ASA) Summer Undergraduate Research or Internship Experience in Acoustics (SURIEA) Program. The program was designed for underrepresented minority groups in order to introduce them to the field of acoustics. After a two-week crash course I was able to experience what it was like working in an architectural acoustic consultation firm, and learn the extensive consultation process at Threshold. Not only that, but learning some of the programs, the methodology, skills, and purpose of Threshold as well. The impact of the program has certainly opened my eyes to the field of architectural acoustics, and how much work has to go into a project for the best possible outcome. In essence, I found the experience to be one of the most impact I had in my life.
Concrete and void: Understanding the acoustics of a parking garage
Authors: DeMaison Nicholas , Belanger Zackery
Published: November 2021

The COVID-19 pandemic has converted musicians at all levels of professional accomplishment into improvising buskers, brocantuers of stray sound in ad-hoc market-places. Lacking the resources to design and build new open-air venues quickly, and facing the possibility of putting group music-making activity on hold, musicians have instead repurposed available spaces. In particular, the pandemic forced the first author's university orchestra from their dedicated performance space into a nearby parking garage. It performed unexpectedly well as a space for acoustic music, in spite of its singular brutalist material and large voids to the outside air. This study, undertaken by the conductor and an acoustician, draws insight from acoustic measurements and wave-based simulations in an attempt to unravel why a space designed for the limited function of supporting cars could give a respectable acoustic showing. The satisfying nature of the shared group experience may compel a widening of our perception of what constitutes an appropriate space for acoustic music making, and a reimagining of the historical line between outdoor and indoor music.
Benefits of voluntary vessel slowdowns to acoustic space reduction for killer whales
Authors: MacGillivray Alexander O. , Li Zizheng , Hannay David E. , Trounce Krista
Published: November 2021

Underwater noise from marine vessels can reduce the acoustic space that is available to marine mammals for performing critical life functions. Likewise, measures such as speed reductions that decrease vessel radiated noise can limit the extent to which acoustic space is affected by marine traffic. To investigate the benefits of voluntary summer vessel slowdowns in Haro Strait and Boundary Pass, the Enhancing Cetacean Habitat and Observation (ECHO) program commissioned a modelling study of acoustic space reduction which focused on two frequency bands relevant to resident killer whales: a communication band (0.5–5 kHz), using a metric termed Listening Space Reduction (LSR) and an echolocation band (15–100 kHz), using a metric termed Echolocation Space Reduction (ESR). The LSR and ESR metrics calculate a relative percent change from the maximum listening or echolocation space under natural ambient conditions to the reduced space caused by anthropogenic noise. Percent LSR and ESR was calculated in the study area at fine spatial (200 m) and temporal (1 min) resolution for scenarios representing baseline and slowdown traffic conditions. Results of this study demonstrate the benefits of voluntary vessel slowdowns on lost listening and echolocation space for resident killer whales.
Acoustic survey of Southern resident killer whale occurrence at the Lime Kiln hydrophone observatory, Haro Strait, Washington
Authors: Yack Tina M. , Wood Jason , Tollit Dominic
Published: November 2021

The aim of this study is to explore temporal and diurnal variation in Southern Resident Killer Whale (SRKW) acoustic activity and their relationship to other marine mammal events and to anthropogenic activity in Haro Strait, Washington. In support of the Vancouver Fraser Port Authority-led ECHO (Enhancing Cetacean Habitat and Observation) Program, six years (2016–2021) of summer/fall acoustic data from the Lime Kiln live hydrophone system (range: 10 Hz–100 kHz) in Haro Strait has been analyzed using PAMGuard software (64-bit Version: 1.15.11; Gillespie et al., 2008). Automated whistle detectors and echolocation click detectors and classifiers were parameterized to detect marine mammals, ships, and echosounders in the dataset. PAMGuard Viewer Mode was then used to review the data and mark all marine mammal and anthropogenic events. The dataset provides important long-term information on marine mammal occurrence and anthropogenic activity in a well described core area of SRKW critical habitat. Daily event logs compiled using custom R script have been used by the ECHO program to better understand the effectiveness of multi-year voluntary commercial vessel slow-downs through Haro Strait and considerable year-to-year and monthly variation in SRKW detections have been identified. Coupled with long-term day-time visual observations of SRKW, the dataset is also useful for assessing the efficacy of PAM detection mitigation methods and night-time activity levels.
Assessment of the impact of broadband acoustic backscattering techniques for understanding the abundance, biomass, and distribution of the Ocean Twilight Zone
Authors: Lavery Andone C.
Published: November 2021

Mesopelagic fishes, which inhabit the Ocean Twilight Zone spanning ocean depths from 200-1000 m, are some of the most abundant vertebrates on earth, and are thought to play an important role in global ocean biogeochemical cycles. And yet there remain large uncertainties in their abundance, biomass, distribution, and behavior. Mesopelagic fishes are difficult to sample, or harvest for the purpose of commercial fisheries, due to their often remote and inhospitable habitats, and their ability to efficiently avoid trawl nets and cameras. As a result, there has been increased interest in using shipboard sonar systems to survey mesopelagic fishes, though little is known about their acoustic properties and target strengths. Recent advances in broadband acoustic scattering systems, post-processing analysis and approaches, and in situ platforms are being used to fill the technology gap and infer in situ target strengths of these elusive mesopelagic fishes. This talk presents an overview of the work done in this area to date, discusses the key challenges that still remain, and assesses the impact of broadband acoustic techniques in advancing our knowledge of the abundance, biomass, and distribution of mesopelagic fishes in the Ocean Twilight Zone. [Work supported by NSF and the WHOI OTZ Project.]
Analysis of multisource non-linguistic sound recognition among cochlear implant subjects
Authors: Chandra-Shekar Ram-Charan M. , Hansen John H.
Published: November 2021

Naturalistic sounds carry rich information related to situational context or subject/system properties that contribute towards an acoustic awareness of the ambient environment. Sensorineural hearing loss reduces the functionality of the cochlea, auditory nerve, or central auditory pathways leading to degradation in auditory processing. Cochlear Implants (CIs) have been widely used to restore impaired auditory function and research advancements have focused on improving speech recognition and overall hearing-related quality of life. However, relatively few studies have investigated non-linguistic Sound Recognition (SR) among CI subjects. In this study, the recognition of sounds in CI users is assessed in a competing condition involving at least two non-linguistic sound sources. Furthermore, an end-to-end audio source separation neural network, SuDoRM-RF, with negative and permutation invariance training, is used for audio source recovery and comparatively assessed for potential identification improvement of non-linguistic sounds among CI users. Objective metrics such as classification accuracy, scale-invariant signal-to-distortion-ratio, and other audio quality related measures are used for assessment and subjective evaluation and compared against listener testing with CI subjects. The proposed study can model multi-source non-linguistic sound problems, the cocktail party effect and potentially provide an effective simulation for realistic listening test scenarios. [Study supported by NIH DC010494-01A.]
David T. Blackstock: Friend, husband, father
Authors: Blackstock Stephen P.
Published: November 2021

David T. Blackstock, my father, was an exceptional and esteemed scholar, scientist, and teacher. He was an even more exceptional human being: a pillar of integrity, a kind and generous friend, a devoted husband, and a loving father. Like many in the audience, I learned so much from him. I have never understood how he had the energy to be so engaged in his research and teaching and, also, so attentive to his family. One of my older brother's childhood friends remarked, shortly after David's passing: “What made him so special was that he remained a good dad despite all the pressures of his professional life.” In this talk, I’ll explore this mystery, and I hope that, along the way, you’ll get to know David Blackstock, the person, a little better. David taught many students how to be good scientists. He taught me how to be a good human being.
David Blackstock and the Applied Research Laboratories at The University of Texas at Austin (ARL:UT): Laying the Academic Foundation for an Applied Laboratory
Authors: Fisher Karl , Penrod Clark
Published: November 2021

David T. Blackstock took a leave of absence from the University of Rochester in 1969 and returned to the University of Texas in his hometown of Austin. ARL:UT was extremely fortunate to have David accept a full-time appointment at the lab as a Faculty Research Scientist in 1970. Over the next fifty years, David nurtured and strengthened the bond between the academic and teaching environment on UT’s main campus and the applied work conducted at ARL:UT. He helped establish coursework that has educated numerous ARL:UT staff members, many of whom had no prior knowledge of acoustics. David increased the recognition of ARL:UT’s acoustic research by attracting internationally renowned scholars and by encouraging our staff to publish their work and take part in the ASA. David was a tireless mentor to our staff and students and created an enduring relationship between ARL:UT and the UT faculty. A truly fitting legacy left for a University Affiliated Research Center.
Early works of David Blackstock in nonlinear acoustics: A view from the former Soviet Union
Authors: Ostrovsky Lev
Published: November 2021

This presentation outlines some moments in the development of modern nonlinear acoustics in the 1960s–1980s, in which Professor David Blackstock played a significant role. In those times of limited contacts between the American and Soviet scientific communities, David was the first to notice our works in the area. He initiated and supported our contacts, first by regular mail (no Internet at that time!) and then, when it became possible, by inviting us to the USA. Our areas of common interest included, among others, radiation and diffraction of nonlinear acoustic beams, horn antennas, and parametric arrays. A few examples of parallel developments in these areas will be described.
Influence of number of hearing aid compression channels on spatial release from masking
Authors: Brennan Marc , Feller Ava
Published: November 2021

Listeners with NH take advantage of differences in the spectrum of speech and noise, dips in the noise level, and spatial separation between sound sources to improve their understanding of speech. Listeners with SNHL are less able to take advantage of these differences. Possibly by not considering the influence of access to spectral information under conditions of amplification, hearing-aids only provide marginal improvement in complex listening environments. This experiment examined whether modifying the number of compression channels can improve spatial release from masking (SRM). We obtained sentence recognition for AzBio sentences presented from in front of each participant. Noise that varied temporally and spectrally over time was presented in a collocated condition and in a spatially separated condition. Test conditions included unaided and binaural amplification with an open-source hearing aid. Four and 16 channels of compression were tested. These experimental conditions were based on prior data that documented improved measures of spectral resolution with 16 relative to 4 channels of compression. We hypothesized that SRM would be greater for the condition with 16 channels of compression, relative to the condition with 4 channels of compression. SRM was hypothesized to be poorest for the unaided condition.
Measuring hearing aid compression algorithm preference with the Tympan
Authors: Lentz Jennifer , Yun Donghyeon , Smiley Stuart
Published: November 2021

In this Tympan challenge, we aim to evaluate listeners’ preferences for different Wide Dynamic Range Compression (WDRC) settings in a real-world environment. While WDRC is used to provide comfort for high-level sounds and audibility for low-level sounds, the nonlinear algorithm distorts the stimulus envelope and can alter the input signal-to-noise ratio (SNR). To date, most measurements of speech understanding and preference under different WDRC parameters (e.g., compression speed and compression ratio) have used pre-processed stimuli presented in a sound-attenuating room. In this study, we plan to measure listeners’ preference for different algorithm settings by using the Tympan in real-world environments. The Tympan will be programmed based on the listeners’ hearing loss, but the user will be able to switch between algorithm settings immediately in their environment using the associated Smartphone app. Using ecological momentary assessment, we will briefly survey the users about their perceptions as they switch between settings. We also will use the Tympan to save acoustic samples and to measure the acoustic properties of the environment and the hearing output, in an effort to determine the drivers of the preference scores [i.e., amount of distortion, degree of audibility, SNR changes (if possible), etc.].
Directionality characteristics of the Tympan open-source hearing aid and earpieces
Authors: Alexander Joshua M.
Published: November 2021

Directional systems in hearing aids are critical for improving speech understanding in the presence of background noise and competing talkers. Tympan is an open-source research platform for speech processing and hearing improvement. The latest Tympan version (Rev E) includes earpieces with a front and a rear microphone, allowing researchers to explore the effects of different directional settings using a realistic hearing aid configuration. The directionality characteristics of the Tympan earpieces were evaluated using a KEMAR in a semi-reverberant sound field. To demonstrate the functionality of Tympan’s directionality features, different software settings were manipulated, including the relative delays and gains between the two microphones. Results will be discussed along with considerations for more advanced directional solutions, such as automatic directional switching, adaptive directivity patterns, binaural signal processing, and beamforming.
Immersive multitalker remote microphone system
Authors: Corey Ryan M. , Singer Andrew C.
Published: November 2021

Hearing aids and other listening devices perform poorly in noisy, reverberant environments with many overlapping sound sources. Remote microphones, which are worn by a talker and transmit low-noise, low-reverberation speech directly to a hearing device, can improve intelligibility even in adverse environments. However, most commercial remote microphone accessories can only be used with one talker at a time and remove the interaural cues that listeners use to localize sound sources. Using the Tympan open-source hardware platform, we demonstrate a multitalker remote microphone system that preserves interaural cues and room acoustic effects. A pair of wireless microphones transmits sound from two talkers to the Tympan system. A set of real-time adaptive filters running on the embedded processor match the magnitude and phase of the remote microphone signals to the sound received by the earpiece microphones. The earpiece output has the signal-to-noise ratio of the remote microphones but the spatial cues of the on-ear microphones. Because the remote microphones provide low-noise reference signals, the system can track motion in real time and does not need to perform explicit source localization or separation.
Damping and dissipation in a fuzzy structure
Authors: Akay Adnan , Carcaterra Antonio
Published: November 2021

Damping describes processes that lead systems to reach equilibrium during which energy either escapes from the system or is redistributed within it. In both cases, the kinetic energy cascades to shorter spatial and temporal dimensions, eventually reaching a state of thermalization. Radiative damping due to energy escape from a system is generally studied using the system-environment paradigm. This approach also explains how a structural fuzzy that refers to ancillary substructures attached to a primary structure leads to apparent damping. It is known that an infinite number of lossless harmonic oscillators with continuously distributed frequencies yield a perfect loss mechanism, since energy has infinitely many paths to travel within the complex structure. For a more realistic structure with a finite number of oscillators, however, energy may return to the primary, unless its frequencies follow a certain distribution (Carcaterra and Akay, JASA). This presentation will focus on the loss mechanism of a fuzzy structure and compare it with dissipation mechanisms at the molecular level.
Electromagnetic articulography is feasible for assessment of speech motor skills in cochlear implant users
Authors: Masapollo Matthew , Oh Yonghee , Goel Jessica , Lowenstein Joanna , Nittrouer Susan
Published: November 2021

Auditory input is essential to the acquisition of fluent speech production, and yet speech production has been scarcely studied in congenitally deaf individuals since cochlear implants (CIs) became a standard treatment. In particular, methods of directly observing speech movements have not been applied, such as electromagnetic articulography (EMA). Several EMA studies have been done with adults with CIs, but those studies used older CI andEMA technology and included subjects with adult-onset hearing-loss, who would have developed speech motor control and phonological representations before losing their hearing. We here investigated whether current EMA technology can be reliably used with CIs by testing (1) whether CIs affect the recordings obtained from EMA, and (2) whether EMA interferes with the signal processing of CIs. In an initial experiment, we calibrated EMA sensors with and without a CI present in the EMA field, and measured impedances of all CI electrodes when in and out of the EMA field. In a subsequent experiment, speech movements were recorded for a normal-hearing talker with and without a CI present in the EMA field. Results indicate that there is no cross-interference between current EMA and CIs, and that EMA data can reliably be obtained from CI users.
A robust tongue shape model from ultrasound recordings of normal and impaired speech
Authors: Changizi Sahba , Laporte Catherine , Ménard Lucie
Published: November 2021

Ultrasound imaging is a helpful tool to observe tongue movements without interfering with natural speech. There exist a variety of models to quantify tongue shape based on contours extracted from ultrasound images. However, these can be affected by poor image quality, e.g., when parts of the tongue are missing from the images due to imaging artifacts. In this study, we investigate the effects of various contour extraction errors on the accuracy and consistency of different shape measures. We developed exponential and polynomial contour perturbation models, then simulated missing tongue tip and root, and investigated the impact of these perturbations on shape measures based on the discrete Fourier transform (DFT), modified curvature index (MCI), and triangular fitting. This was applied to a set of CV utterances collected from healthy and impaired speakers. Results demonstrate the effectiveness of DFT and triangular fitting in clustering different phonemes despite the added noise. A high degree of correlation was found between the DFT coefficients of the perturbed and original tongue contours. There is also a trade-off between the robustness of the model and sensitivity to minor actual differences in tongue shape. Sometimes, these slight differences help group tongue shapes that differ, e.g., due to coarticulation effects. Therefore, we have attempted to improve the precision of the DFT model by adding palatal contact information.
Effects of dynamic pitch manipulation methods on speech perception in noise by older listeners with hearing loss
Authors: Shen Jing , Wu Jingwei
Published: November 2021

Dynamic pitch, as defined by the variation in fundamental frequency (f0) of speech, is a major acoustic cue in speech perception. While dynamic pitch manipulation negatively affects speech perception in noise on a group level, there is substantial variability across older listeners with hearing loss. The manipulation method used in previous studies, however, may distort pitch contours in natural speech. In this study, a new manipulation method is employed by exaggerating pitch contours above mean pitch. The primary purpose of the study is to compare the effects of these two manipulation methods on speech recognition in noise by older listeners with hearing loss. The secondary purpose is to examine the connection between individuals’ responses to dynamic pitch manipulation and intonation perception. Speech reception threshold in noise was measured from 8 older listeners (mean age 74.5 years) with mild-moderate sensorineural hearing loss. Intonation perception was measured by a 2-alternative discrimination paradigm. Data up to date suggest a stronger effect from the new method, with the weakened dynamic pitch being more beneficial than the original pitch contour. Further, individuals’ intonation perception is associated with their response to pitch manipulation. The theoretical and clinical implications will be discussed. [Word supported by NIH.]
Amplitude modulation of background noise varies listeners’ spectral weights for sentence recognition
Authors: Shen Yi , Langley Lauren
Published: November 2021

The band importance function that captures how the spectral weight varies across frequencies was estimated for sentence recognition in noises with steady-state or fluctuating temporal envelopes from ten young, normal-hearing adult listeners. The test sentences were from either the IEEE or AzBio corpus. The background noise was a 12-talker babble, either unmodulated or amplitude-modulated using an 8-Hz sinusoidal modulator. In the co-located condition, the noise was presented from the same loudspeaker as the target sentence in front of the listener (0°). In the spatially separated condition, the noise was presented simultaneously from two loudspeakers on either side of the target speaker (±90°). The co-located condition was replicated in a separated test session, at least one week from the first session, which demonstrated the reliability of the estimated band importance functions. With the introduction of amplitude modulation, an increase of spectral weight in the 2-kHz frequency band and a decrease of weight in the 250-Hz band was observed, which was consistent for the two test materials and for the two spatial placements of the noise. Compared to amplitude modulation, spatial separation between the target and noise had a less influence on the band importance function.
A Gaussian-mixture-model-based approach to classifying vowel place in speech signals
Authors: Patnaik Ritik , Choi Jeung-Yoon , Shattuck-Hufnagel Stefanie
Published: November 2021

In recent years, speech recognition systems have dramatically improved in performance through the development of general machine learning techniques. However, it is not always straightforward to interpret the mapping from the signal to the detected category. In the present work, we focus on the goal of transparency, specifying the processing steps that lead to robust modeling of vowel place using simple, descriptive Gaussian mixture models. We present a pre-processing and detection framework for vowel place, involving formant measurements, smoothing, and the GMM. This research aims to classify vowel place as a part of a larger speech recognition system. Vowel place was divided into 8 groups based on tongue advancement [Front/Back], height [High/Mid/Low], and root [Atr/Ctr]. Studies were performed using ∼700 vowel-consonant-vowel utterances from the LAFF VCV database.
Acoustic analysis of vocal effort and speaking style
Authors: Chan May Pik Yu , Liberman Mark
Published: November 2021

“The singer’s formant” is used by singers during voice projection. While a similar “actor’s formant” has been found (Leino, 1993), other work finds greater source effects in projected voices (e.g., Master et al., 2012). It remains unclear whether differences in source and/or filter remain among non-actors/singers in varying speaking styles. Recordings from the SRI-FRTIV corpus (Shriberg et al., 2008) were used to examine the effects of vocal effort and speech style on vocal characteristics. 34 speakers of American English spoke in up to three levels of vocal effort in (1) Interview, (2) Conversation, (3) Reading, and (4) Oration tasks. The following measures were measured by LTAS based on the mid-50% of the recording’s duration: (a) CPPS; (b) L1-L0; (c) alpha ratio; (d) mean frequency of the lowest peak; (e) the level difference between strongest peaks at 3–4 kHz and 0–1 kHz (“the actor’s formant”); the level difference between the first formant region (300–800 Hz) and the (f) 1–2 kHz, (g) 2–3 kHz, (h) 3–4 kHz, and (i) 4–5kHz range. Preliminary results using PCA find that general measures of spectral slope (PC1: h, i, c, g, b) better capture differences in vocal effort and speech style than more fine-grained source/filter measures (PC2: e, f, a, b, d).
Face masks, speech intelligibility, and listening effort
Authors: Carraturo Sita , Brown Violet A. , Van Engen Kristin J. , Peelle Jonathan
Published: November 2021

The use of face masks recently has raised awareness about their effects on speech comprehension. In a series of two studies, we assess how different masks speech intelligibility and listening effort. In the first study, we compared four mask types in three noise levels for young and older adult listeners. Stimuli were presented audiovisually. Results showed that, in quiet, speech intelligibility was not greatly affected by any of the masks relative to no-mask conditions. However, in background noise, all masks reduced intelligibility. Masks with transparent windows and cloth masks with filters resulted in the lowest intelligibility scores, while surgical face masks had the least effect. Participants’ subjective effort ratings also reflect that comprehending speech through face masks requires greater effort. Overall, older adults’ listening effort ratings were higher and their intelligibility scores were lower. In the second study, we assess listening effort with pupillometry. We present the same stimuli to a group of young adults in six audio-only conditions: no-mask in quiet, no-mask in moderate noise, and four masks in moderate noise. In addition to intelligibility accuracy and pupil dilation, we also collect subjective effort and performance ratings, pure tone averages, and working memory performance scores.
Estimation of sound speed profiles in deep water using perturbative inversion
Authors: Edelmann Geoffrey F. , Lingevitch Joeseph F.
Published: November 2021

A method to invert for the local sound speed profile (SSP) using only acoustic wavenumbers is proposed. Ocean sounds can be treated as acoustic energy trapped as discrete modes within the water column. Using estimated Eigenvalues (wavenumbers) from one or more modes, a method to numerically invert for the SSP can be posed as a linear Fredholm integral equation of the first kind. Therefore, the vertical SSP can be estimated with a well-placed, sufficiently long, array at one or more frequencies. Though this inversion can be unstable and non-unique, recent improvements in sparse inversions can lead to robust estimates even without an accurate starting SSP. Using the perturbative difference between the estimated wavenumbers and those calculated from the acoustic kernel, both the SSP and kernel are updated each iteration. Careful consideration must be made of the acoustic frequency, number of modes, a priori environmental information (e.g., water depth), and array length. The method will be first demonstrated on simulated recordings based on the LIDDEX data set. [Work supported by ONR.]
Automated matching of long range underwater acoustic arrivals to predictions using a minimum variance Approach
Authors: Graupe Cristian E. , Van Uffelen Lora , Worcester Peter F. , Dzieciuch Matthew , Howe Bruce M.
Published: November 2021

An automated method was developed to align underwater acoustic measurements taken at various depths and ranges to a reference model of acoustic arrival structure. Data used to demonstrate the method were collected by four autonomous underwater vehicles deployed in the Philippine Sea as part of an ocean acoustic tomography experiment. The arrivals were measured in the upper 1000 m of the ocean at ranges spanning several hundred kilometers from 5 moored acoustic tomography sources. The primary objective is to accomplish automatic source-receiver ranging by aligning measurements of long range acoustic arrivals to a single reference model. Acoustic arrival time structure for pulse compressed signals at long ranges is relatively stable, yet real ocean variability presents challenges in acoustic arrival matching. The presence of internal waves scatters the acoustic arrival structure and can introduce spurious arrivals in the measured data. This method takes advantage of simple projections of the measured structure onto the model space with constraints informed by scattering statistics consistent with the Garrett Munk internal wave energy spectrum. Compared to manual matching of the measured arrivals to eigenray models, more than 90% of the automatically obtained range estimates were within 150 m of the manually obtained range estimates.
The waveguide invariant: Wavefield structure, ray stability, time spreads and modal dispersion
Authors: Brown Michael G.
Published: November 2021

Prior to the seminal work of Chuprov and Grachev, who introduced the underwater acoustic waveguide invariant, the asymptotic equivalent of the same quantity was recognized as playing an important role in Hamiltonian dynamics. A consequence is that the waveguide invariant controls, to a large extent, underwater acoustic ray dynamics. In this presentation some of the less well known properties of underwater acoustic wavefields, based on both ray- and mode-based descriptors, that are controlled by the waveguide invariant are reviewed. These properties include overall wavefield structure, ray stability, time spreads and modal dispersion. [Work supported by ONR.]
Open-source deep learning models for acoustic detection and classification of orcas
Authors: Sakib Sadman , Bergner Steven , Campbell Dave , Dowd Mike , Frazao Fabio , Joy Ruth , Kirsebom Oliver S. , Nguyen Hong Duc Paul , Padovese Bruno , Randon Marine , Riera Vuibert Amalis , Veirs Scott , veirs val , Wladichuk Jennifer , Yurk Harald
Published: November 2021

Current efforts to acoustically study and monitor killer whales in British Columbia (BC), including the endangered population of Southern Resident killer whales (SRKW), are hampered by the lack of sufficiently accurate sound detection and classification algorithms. Recently, several research groups have reported significant improvements in algorithm performance utilizing deep neural networks. However, for most practitioners, these novel tools remain out of reach. To bridge this gap, we are developing a set of open-source deep learning models for acoustic detection and classification of BC's killer whales. These models will be made publicly available along with expert-curated training and test sets to facilitate further development and applications. We are collaborating with Orcasound to deploy the models on their live data. We are also working together with the PAMGuard developer team to ensure that our models can be seamlessly imported and used in PAMGuard, a widely used open-source software platform for passive acoustic monitoring. In this contribution, we will provide an overview of our deep learning methodology and present preliminary results on model performance, with particular attention to the model's ability to handle diverse and variable acoustic environments and generalize to new “unseen” environments.