bluuebunny/crossref_metadata_2025 huggingface dataset:
Functional changes in brain organization after de novo audiomotor learning: An fMRI investigation
Authors: van Vugt Floris , Masapollo Matthew , Ostry David J.
Published: July 2024

To learn to talk or play a musical instrument, the brain must acquire a “mapping” of the relationship between movements and their acoustical consequences. However, it remains unclear how this type of audiomotor learning alters the functional organization of the brain, and what neural networks support consolidation of that learning. This study used functional magnetic resonance imaging (fMRI) to measure functional changes in brain organization as a result of audiomotor learning from scratch. We used a novel paradigm in which subjects learned to move a joystick in different directions in a 2D workspace to achieve speech-like acoustical targets. At the end of each movement, subjects received auditory feedback corresponding to the sound associated with the direction that they moved in. Before and after training, we used resting-state fMRI to assess learning-related changes in functional connectivity. Behavioral results show that, over the course of practice with feedback, subjects gradually produced joystick movements with fewer errors, indicative of learning. Furthermore, some of this learning was maintained to the second day, indicating subjects started forming durable performance gains. Analyses of the fMRI data are currently underway and aimed at localizing changes in neural activity that scale with behavioral indices of audiomotor learning.
Evaluation of efferent influences on neural coding using pre-clinical models of sensorineural hearing loss
Authors: Farhadi Afagh , Hauser Samantha , Sivaprakasam Andrew , Heinz Michael G.
Published: July 2024

The medial olivocochlear (MOC) efferent system is less explored than the ascending auditory pathway but likely contributes in important ways to neural coding and perception. These effects are thought to vary across stimulus configurations, anesthetic states, and subtypes of sensorineural hearing loss (SNHL). To explore effective assays of MOC effects on neural coding, we have recorded Interleaved otoacoustic emissions (OAEs) and envelope following responses (EFRs) from several pre-clinical SNHL chinchilla models. Our preliminary observations include increases in OAEs with inner-hair-cell loss and anesthesia, which may be due to reduced efferent strength. Additionally, we observed enhanced EFRs with an added noise masker, which also could be related to efferent effects. We are using sedated and awake OAE comparisons to develop a standard efferent assay for use in neural-coding studies. Interleaved recording of OAEs and EFRs track cochlear-gain and neural-coding changes during acoustic stimuli. A recently developed modeling framework (Farhadi et al., 2023 JASA) that includes different MOC projection pathways, including midbrain modulation-sensitive inputs, is used to guide most-effective stimulus selection. Ultimately, this model-guided experimental framework will provide unique guidance for testing MOC hypotheses related to neural coding.
Tone selection for cochlear implants using peak-finding and frequency bin overlap
Authors: Keen James H. , Yoshida Sanichiro
Published: July 2024

The Advanced Bionics cochlear implant devices employ a method of allocating static frequency bins to electrodes based on the natural tonotopic organization of the cochlea. Many studies show that there is a significant frequency-to-place mismatch in many subjects, but that over time the brain adjusts to these mismatches. Also, most of the tonal information in human speech is present in the lower end of the frequency spectrum, where there are few frequency bins and electrodes available to represent this information. Here, adjustments to the frequency bin allocation algorithm used in the crowdsourced CI Hackathon code are made to allow a more accurate representation of the original signal in the lower registers. A peak-finding and selecting method is used to find significant peaks regardless of frequency bin, then bins are overlapped to allow more accurate representation of tones near the borders between channels and peaks which may be near to each other.
Parametric study of blind-label acoustic subwavelength imaging
Authors: Lin Jinuan , Ma Chu
Published: July 2024

There is a long-existing tradeoff between the imaging resolution and the penetration depth in imaging systems caused by the diffraction limit. We developed a “blind label” approach to tackle this problem, which significantly improves the practicality of acoustic subwavelength imaging in biomedical ultrasound imaging, non-destructive testing, and other acoustic sensing and communication applications. The “blind labels” in our system refer to randomly distributed acoustic scatterers with deep-subwavelength sizes whose exact locations and trajectories are not necessary information in image reconstruction. Our imaging framework is composed of two parts: (1) spatial mixing: a physical process that converts the originally evanescent components in the scattered waves from the object to propagating components that can reach the far-field detector and (2) computational reconstruction. In this talk, we will mainly report our quantitative investigation of the system parameters’ impact on the performance of the blind-label subwavelength imaging system, providing guidance to future system setups in various applications.
Tollmien–Schlichting wave manipulation by a multi-input multi-output phononic subsurface
Authors: Willey Carson , Barnes Caleb , Chen Vincent , Rosenberg Kevin , Medina Alberto , Juhl Abigail T.
Published: July 2024

Recently, there has been a reinvigorated effort to identify passive control mechanisms to reduce drag on vehicles moving through a fluid medium. In 2015, Hussein et al. engineered a phononic crystal subsurface (PSub) to interact with Tollmien–Schlichting waves of a channel flow through an interaction surface, which caused a localized reduction in the kinetic energy of the flow. Since then, arrayed PSubs, Helmholtz resonators, and other embedded structures have been studied for their ability to produce similar effects. In this talk, an implementation of a multi-input multi-output (MIMO) PSub is presented and its ability to delay the onset of turbulence is shown to depend on simultaneously satisfying single-input single-output (SISO) PSub phase requirements at both interaction surfaces of the MIMO PSub. The MIMO architecture provides a method to place an arbitrary phasing between the T-S wave induced forcing and the displacement response of the interaction surface and can be optimized for the flow conditions of the environment.
A photographic analysis of Mach wave radiation from a rocket plume
Authors: Hart Grant W. , Gee Kent L. , Hintz Eric G. , Nuccitelli Giovanna , Mahlmann Trevor
Published: July 2024

At 7:30 AM on October 6, 2020 Space-X launched a Falcon-9 rocket from pad 39A at Kennedy Space Center. Photographer Trevor Mahlmann had positioned his camera in the location where the rocket would pass in front of the rising sun and took a series of images of that encounter. These images are visually stunning, but they are also scientifically useful. The high-intensity sound and shock waves originating in the plume are imaged by passing in front of the sun, particularly near the edge of the sun. This can be considered a background-oriented schlieren system. The sound from a supersonic rocket plume is thought to be due to Mach wave radiation, but the details are not yet well understood. We are analyzing these images to determine the position and radiation characteristics of the sound source in the plume. The results of this analysis will be presented.
Acoustic source characterization of shock-associated noise in an installed, full-scale F404 engine
Authors: Mathews Logan T. , Gee Kent L.
Published: July 2024

Shock-associated noise in supersonic jets is an important factor in acoustic radiation, particularly in the upstream direction. A previous paper [L. T. Mathews et al., J. Acoust. Soc. Am. 154, A325 (2023)] discussed a preliminary source characterization of shock-associated noise in a full-scale, installed tactical jet engine. Acoustical holography was used to reconstruct the acoustic behavior near the jet and high-amplitude features were produced that were consistent with shock-associated noise sources. This paper presents a more detailed characterization of shock-related noise in the jet using higher-fidelity methods, such as subarray processing and bandwidth extension. The spatial and spectral characteristics of the shock cell noise sources are discussed. A virtual reference decomposition method is used to examine the source and radiative characteristics of each detected shock noise source. The results are compared with shock noise characteristics in the literature. [Work supported by ONR Grant No. N00014-21-1-2069.]
Multiple wavepacket source decomposition methods applied to an F404 engine noise source
Authors: Olaveson Tyce W. , Gee Kent L.
Published: July 2024

Characterizing jet noise sources is an important part of noise reduction efforts. Many equivalent source models (ESMs) derived from inverse methods lack a compelling physical interpretation. Connecting the source model to flow properties is an important part of understanding noise radiation methods. Wavepackets are coherent, spatiotemporal structures observed in jet turbulence. Mathematical expressions describing wavepackets have been used in modal decompositions of the turbulent flow. Similar structures appear in frequency domain ESMs and these methods have been applied to create physically meaningful, reduced-order models. This paper applies a multiple wavepacket decomposition method developed by Harker [B. M. Harker, BYU Ph. D Dissertation (2017)] to acoustic data collected near a T- 7A-installed F404 engine. Individual wavepackets are used to create total-field reconstructions and comparisons are made to the dual-lobe behavior observed in full-scale jets. Finally, sound power characteristics of each wavepacket are used to effectuate a sound power decomposition of the noise source. [Work supported by ONR Grant No. N00014-21-1-2069.]
SoK: Sensor wars: Attacks and defenses on acoustic sensors
Authors: Castro Fidel , Chandra Kavitha , Arias Orlando
Published: July 2024

In this talk, we will examine attacks that can be performed against sensors that have become prevalent in smart devices, Internet of Things, and Cyber-Physical Systems. These devices have become part of our everyday life, integrated, for example, in health monitoring solutions, autonomous vehicles, and home automation. A classification of current threat models on sensors is presented. Of particular interest are attacks that make use of interference to trick devices into performing unintended actions. This talk serves as a summary of knowledge on the state of the art in utilizing sensor data for improving the security of smart devices and systems with the goal of inspiring new interdisciplinary research between the acoustics and cybersecurity communities.
Exploring a planet with infrasound: Challenges in probing the subsurface and the atmosphere
Authors: Näsholm Sven Peter , Brisaud Quentin , Turquet Antoine , Kaschwich Tina , Froment Marouchka
Published: July 2024

Infrasound waves have shown great potential to retrieve a range of geophysical parameters across scales, such as atmospheric structures, surface and buried source characteristics, and seismic velocity structures. In particular, infrasound generated by seismic waves coupling to the atmosphere can provide unique insight into a planet's interior. However, utilizing infrasound data require efficient forward wave simulation techniques and an accurate description of waveform sensitivity to source and medium parameters. Even under idealized conditions, many of the inverse problems associated with infrasound-based probing are inherently ill-posed, requiring regularization or other approaches to yield reliable output. In this contribution, we highlight recent research results from our group and collaborators, tackling atmospheric probing at smaller and global scales, as well as innovative approaches to speed up infrasonic wave propagation modeling. We also call attention to the objectives and early results from a newly launched project focusing on the feasibility of exploring the interior of Venus using infrasound recorded from balloon platforms.
Listening effort for L2 accents: Adults’ adaptation to Mandarin accented english
Authors: Altmiller Ruth , Mallard Mel , Van Engen Kristin J.
Published: July 2024

Using task-evoked pupillary response (TEPR) and dual-task procedures, prior research has shown that adults recruit additional cognitive resources when processing fully intelligible L2-accented speech compared to speech in their own L1 accent (McLaughlin and Van Engen, 2020; Brown et al., 2020). In this study, we investigated the relationship between three prosodic measures (relative word duration variance, pitch stability, and pitch range) and changes in listening effort for L1 and L2 speakers over the course of an experiment. Using growth curve analysis, we found significant interactions between each of the three measures and trial number, indicating that prosodic factors influence speech adaptation. However, these interactions were in opposite directions for the L1 and L2 speakers. Thus, adult monolingual English listeners rely on prosodic information to adapt to a particular speaker’s voice, but use that information differently based on speaker identity.
Target-masker onset asynchrony modulates linguistic release from masking
Authors: Olmstead Anne J. , Viswanathan Navin , Burgos Mercado Andrea , Caplan Grace
Published: July 2024

Speech-in-speech recognition is a challenge that listeners often encounter. Performance in such situations is improved if the competing speech is in a language different from the target—a phenomenon called Linguistic Release from Masking (LRM). LRM occurs due to a combination of energetic masking that arises from the physical overlap between the target signal and the masker and informational masking that arises from cognitive, attentional, and other factors. The contributions of informational masking to LRM is poorly understood. In the current study, we manipulated informational masking by varying the target-masker onset asynchrony while holding energetic masking constant. Typical, monolingual English listeners transcribed BKB sentences with either English or Mandarin two-talker babble in the background. The target sentences started either simultaneously with the masker, 500 ms after the masker, or 1000 ms after the masker. Listening accuracy was higher for the Mandarin than for the English masker, replicating typical LRM. However, the size of LRM was moderated by onset asynchrony with larger effects for longer lag times. This finding suggests that the detrimental effect of English masker accrues with lag. Implications of this finding for the role of informational masking in speech-in-speech listening will be discussed.
Blind passive signal detection via dictionary learning in unknown multipath time-spreading distortion underwater channels
Authors: Rashid Rami , Abdi Ali , Michalopoulou Zoi-Heleni
Published: July 2024

Blind passive signal detection is a challenging endeavor since typically there is no prior knowledge of the transmitted signal. This becomes further complicated in time-spreading distortion (TSD) underwater channels [R. Rashid, E. Zhang, A. Abdi, and Z. H. Michalopoulou, “Theoretical and experimental multi-sensor signal detection in time spreading distortion underwater channels,” Proc. Oceans (2022)], where due to the presence of multiple propagation paths, the unknown signal is convolved with an unknown channel impulse response. In this paper, we introduce and develop a blind passive signal detection method, using dictionary learning [M. Sadeghi, M. Babaie-Zadeh, and C. Jutten, “Dictionary learning for sparse representation: A novel approach,” IEEE Signal Process. Lett. (2013)]. In our blind passive signal detection method, we use the received data to estimate the unknown signal, and also to separate it from the unknown channel impulse response. We have conducted simulations and underwater experiments, to generate receiver operating characteristic curves, to study the performance of the proposed method. The high detection probabilities of the blind method, compared to the replica correlation integration method—that needs to know the transmitted signal for matched filtering—demonstrate the usefulness of the method for passive detection of unknown signals in unknown TSD channels.
Which absorption coefficients are correct?
Authors: Herreman Kevin
Published: July 2024

Each year absorptive material samples are sent to various accredited acoustic laboratories around the country by manufacturers who want to verify the performance of their products. Results are published as indisputable validation of the product absorption performance by the manufacturer. As no recent interlaboratory study results for ASTM C423—Standard Test Method for Sound Absorption and Sound Absorption Coefficients by the Reverberation Room Method are available, the Owens Corning Acoustic Research Center initiated a private interlaboratory study. A small set of accredited acoustical laboratories tested a set of the original National Voluntary Laboratory Accreditation Program reference panels. The resulting data and differences in the measured absorption coefficients will be reviewed.
Using absorption coefficients for baffles in room acoustics simulations
Authors: Jaramillo Ana M. , Olson Bruce
Published: July 2024

As consultants, we often find ourselves wondering how to apply sound absorption coefficients on simulated baffles. The reported coefficients are relative to the floor area represented by an assembly of several baffles, and these are often not spaced the same distance that will be used in a specific project. Furthermore, sound transmission through baffles without a hard core is not represented in the simulation. By modeling a lab scenario and reproducing the results of a number of measurements, we intend to create a best practice guide for using these coefficients in simulations.
Acoustic propagation through a biological deep scattering layer at the New England shelf break
Authors: Kukshtel Natalie , Lavery Andone C. , Lin Ying-Tsong
Published: July 2024

The New England Shelf Break is a dynamic ocean environment with strong spatial variability due to complex physical processes and interactions with warm core rings originating from the Gulf Stream. An acoustic autonomous underwater vehicle (AUV) was deployed in the New England Shelf Break Acoustics (NESBA) experiment in May 2021 to investigate environmental variability and its effect on sound propagation. The AUV system was comprised of a modified REMUS 600 vehicle with a hull-mounted 3.5 kHz transducer, a downward-facing EK80 echosounder, and a towed linear hydrophone array. Shipboard EK80 data measured during the AUV mission showed the presence of a biological deep scattering layer. Preliminary analysis of AUV source signals passing through the layer suggested significant attenuation compared to signals not passing through the layer. To investigate this further, a parabolic equation (PE) model with range-dependent attenuation patches in the water column was constructed to replicate the biological attenuation through the scattering layer. The model uses estimates of absorption and scattering derived from shipboard and AUV EK80 data. Through this study we aim to better understand the scattering effects of this deep biological layer on acoustic propagation. [Work supported by the Office of Naval Research.]
Listening to the acidity of the ocean: Inversion of passive deep sea acoustic data for pH
Authors: Uzhansky Ernst , Barclay David R.
Published: July 2024

Ocean acidification is an ongoing concern due to its impact on the marine ecosystem. The volume integrated pH of sea water can be determined from the depth-dependence of ambient sound, which depends on the acoustic absorption properties of seawater. For a wind-driven noise in the ocean over the band 1–10 kHz, two main contributions to sound attenuation are associated with the ionic relaxation of boric acid (<3 kHz), related to pH, and magnesium sulfate (>3 kHz), unrelated to pH. When local winds are strong (>10 m/s), the ambient noise is dominated by locally generated surface noise and has a depth-independent directionality and a weakly frequency and depth-dependent intensity, due to sound absorption. By measuring the attenuation of sound in a wide frequency band, it is possible to estimate pH by comparing the experimentally measured attenuation with an analytical theory of passive acoustic absorption spectroscopy. Measurements of the depth-dependent ambient sound field were carried out in the Philippine Sea, Mariana Trench, and Tonga Trench throughout 2009—2021. The wideband (5 Hz—30 kHz) acoustic data were recorded with untethered free-falling autonomous recording systems carrying two or four hydrophones.
Some thoughts on ultrasound futures
Authors: Thomenius Kai E.
Published: July 2024

Development of ultrasound technology began in early 1950s and has maintained a fast pace. In this talk I will review some of this history with the goal of setting the stage for future development. I have opted to split this development chronology into four stages by the nature of the electronics with the culmination of software-based systems. This talk will consider near-term futures that are gained from technologies such as software beamformation. An aid in defining this future will be information gained from the programs of various technical conferences. It is assumed that much of the work presented at such meetings has gone through broader review processes such as reviews of grant proposals and manuscript submissions. A hopefully interesting recommendation that arises from this analysis is towards research for improved understanding of sound/tissue interactions based on received echo data (e.g., channel data) and how this understanding may be used to improve image formation and increase our understanding of pathologies. An aspect that may arise from this is the potential of being able to define an upper limit on performance of ultrasound scanners in a broad patient population.
Improved beamforming by accounting for multiple domain shifts and sources of degradation
Authors: Pan Ying-Chun , Schlunk Siegfried , Khan Christopher , Byram Brett
Published: July 2024

A number of mechanisms are known to degrade ultrasound images. To address these issues, many beamforming strategies have been proposed including a slew of recent approaches centered around deep learning techniques. Most deep learning methods target a single type of image degradation. Here, we will simultaneously address multiple sources of image degradation within the same beamformer. In particular, we will address phase aberration, reverberation and off-axis scatting within a single network. Within this context of training networks to address multiple sources of image degradation, we will highlight the problem of domain shift in ultrasound beamforming deep networks. Domain shift is the mismatch in the statistics of the training data and the data encountered in the intended use case that reduces the performance of the trained deep network. We will show that ultrasound beamformers struggle with domain shift on both the input side and the output side of the networks, and we will present strategies for addressing both domain shifts including the shift on the output side where there is no ground truth data to learn from.
Application of differentiable programming to wave simulation
Authors: Stanziola Antonio , Arridge Simon , Cox Ben , Treeby Bradley
Published: July 2024

Wave simulations play a crucial role in a wide range of scientific and engineering applications, including seismic imaging, optical design, and acoustic modeling. Here we explore the advantages of differentiable programming in the context of acoustic wave simulation. Differentiable programming enables us to treat wave simulation as a differentiable function, allowing for the automatic computation of gradients with respect to any continuous input parameter. We demonstrate how this approach can be applied to various types of wave simulations, such as Pseudo-spectral time-domain solvers or iterative solvers. Implementing wave simulators via differentiable programming achieves several benefits. First, it enables efficient and accurate sensitivity analysis: This is particularly valuable for optimization and uncertainty quantification tasks. Second, it facilitates the incorporation of wave simulations into machine learning frameworks, enabling the integration of simulation-based models with data-driven approaches. Third, differentiable programming can accelerate the calibration and inversion of wave simulation models, making it easier to match simulated results to observed data. We present practical examples and discuss potential applications in fields such as geophysics and medical imaging. Our findings highlight the potential of this approach to advance the state-of-the-art in wave simulation techniques and their integration into larger computational pipelines.
Stochastic ray tracing implementation for sonic boom propagation modeling
Authors: Marini Chloe A. , Riegel Kimberly A.
Published: July 2024

Sonic boom propagation in large urban areas needs to be understood to determine the impact it will have on residents. In previous work, a combination of ray tracing and radiosity method was used to model the reflections of the sonic booms around large structures. Radiosity is a memory intensive method which requires extensive computational resources as the environment becomes more complex, whereas stochastic ray tracing does not require substantially more resources for more complicated environments. This study examines the feasibility of using stochastic ray tracing to simulate the diffuse reflections of sonic booms. Receiver graphs comparing stochastic ray tracing and radiosity methods for several environments will be shown, along with their computation times.
Individual response trends to urban air mobility noise in a laboratory study
Authors: Vaughn Aaron B. , Christian Andrew
Published: July 2024

Advanced Air Mobility, of which Urban Air Mobility (UAM) is a subset, presents new opportunities for more dynamic aviation transportation systems. It is essential to understand the human response to the noise of these vehicles for sustainable operations. This research aims to investigate the relationship between the noise level and number of events on individual human annoyance to UAM vehicle noise. A “noise and number” laboratory psychoacoustic study was conducted in the Exterior Effects Room at NASA Langley Research Center in January 2023. A total of 38 participants listened to 4-minute audio clips of UAM vehicle flyover noise and provided their annoyance response on an 11-point numerical scale. A test hypothesis was that annoyance to multiple flyovers can be found by adding the annoyance responses to individual flyovers. Results for the overall test subject pool suggest that annoyance grows faster than hypothesized as the number of aircraft events increases. This trend of faster annoyance growth only seems to hold when the individual flyovers are heard as distinct events. Parsing the data down to individuals provides further insight into the mechanisms contributing to the increased annoyance with number of events.
Wind noise due to flow induced around a windscreen in large-scale turbulence
Authors: Lyons Gregory W.
Published: July 2024

Turbulent wind noise on microphones is a ubiquitous problem for sound measurement and recording outdoors. Windscreens, such as open-cell foam spheres, are effective at reducing wind noise. The unsteady pressure sources induced on the windscreen surface must contribute less noise on average than the stagnation pressure on a bare microphone, or windscreens would not be effective. To quantify this noise reduction mechanism, a model is presented for the unsteady pressure within an impermeable windscreen of arbitrary shape immersed in an initially isotropic turbulent flow. Only turbulent scales larger than the windscreen are considered, which contribute the most intense low-frequency band of the noise spectrum in most practical situations. The inhomogeneous velocity field around the windscreen is modeled in terms of an induced irrotational blocking field that meets the kinematic boundary condition. The interior pressure is expressed as a convolution of the surface pressure field with a filter function in wavevector space. The wind noise wavevector spectrum is then shown to be only a function of the inflow isotropic velocity spectrum and the windscreen shape. Solutions are obtained for the pressure frequency spectrum within a spherical windscreen for a von Kármán turbulence model and compared with prior results in literature.
A reduction in near-field hydroacoustic flow noise using shark skin-inspired surfaces
Authors: Stocking Jonathan , Sampath Kaushik , Xu Nicole , Geder Jason , Matt Silvia
Published: July 2024

Recent studies have demonstrated improved hydrodynamic performance for hydrofoils and uncrewed underwater vehicles (UUVs) using passive surface geometries such as riblets and shark skin-inspired denticles. However, little is known about the impact of added surface roughness on the production of flow-induced noise, a critical design consideration for UUVs in sensitive environments. We present here experimental results of near-field hydroacoustic noise measurements for boundary layer flow over smooth and bioinspired denticle-covered surfaces. A 3 in. wide and 10 in. long segment of staggered denticles was fabricated in-house using photopolymer 3D printing, and flow and acoustic measurements were made in a custom-built flow channel using particle image velocimetry (PIV) and miniature hydrophones. Comparing acoustic power spectra over flat and denticle-covered plates, we find both a scale- and frequency-dependent response in radiated noise. At low flow speeds (Re ∼ 20,000), the denticle surface shows a 20 dB enhancement in radiated noise at frequencies below 1000 Hz, but no change at higher frequencies. While at high flow speeds (Re ∼ 60 000), the denticle surface reduces radiated noise by ∼10 dB for frequencies between 4000 and 8000 Hz. Analysis of PIV data will elucidate the flow physics responsible for these effects. [Work sponsored by Office of Naval Research.]
My great big problem with vowels
Authors: Flege James E.
Published: July 2024

How vowels are produced in a second language (L2) is determined by several factors. One is cross-language mapping: how/if vowels in the L2 phonetic system are categorized in terms of native language (L1) vowels and the extent to which they are judged to resemble the L1 vowels perceptually. Another is input: the quantity and quality of the L2 vowels to which learners have been exposed. L1- L2 mapping patterns are sometimes reported in studies of L2 vowel learning, but they may differ across individuals and change as learners gain L2 experience. Coarse estimates of quantity of L2 input are usually reported but estimates of exposure to foreign-accented L2 input are virtually non-existent. Even if we had adequate measures of L2 input, other serious problems would remain. Once the L1 phonetic system is established, language users may attend less to the surface phonetic properties of vowels they hear when conversing in the L1 and also in the L2. This talk will focus on problems inherent in (a) understanding how the phonetic input received in an L2 is used, and (b) gauging degree of L2 learning success.
Automated detection of fin whale calls recorded with distributed acoustic sensing
Authors: Goestchel Quentin , Wilcock William S. , Abadi Shima
Published: July 2024

As the global biodiversity crisis intensifies, wildlife monitoring has become a necessity. From an oceanographic perspective, the tracking of baleen whales allows studies of their habitat use and can support call density estimates, which are indicative of ocean health. Distributed Acoustic Sensing (DAS) is a promising observational technique that measures strain rates along a spare optical fiber with a spatial resolution of tens of meters to distances of ∼100 km. Over 4-days in November 2021, a public domain DAS dataset was collected on the submarine cables of the Ocean Observatories Initiative Regional Cabled Array off the coast of central Oregon. The experiment recorded the acoustic signals from tens of thousands of fin whale calls as well as blue whale calls, ship signals and T-phases. We will describe preliminary efforts to develop automated methods to detect and localize fin whale calls using small representative examples of the DAS data. Our longer-term goal is to extend this approach to the full data set to understand the sensitivity of DAS to fin whale calls as function of cable geometry and seafloor characteristics and to study the distribution of calling fin whales in coastal waters off central Oregon. [Work supported by ONR.]
Moving cargo, keeping whales: Investigating solutions for ocean noise pollution
Authors: ZoBell Vanessa M. , Hildebrand John , Frasier Kait
Published: July 2024

Human activities introduce high levels of noise into the ocean. Commercial shipping, in particular, has increased to the point that ships make a larger contribution to ocean noise than natural noise sources for most ocean locations and over a broad range of frequencies. Primeval ocean noise levels, those that would have been experienced before the advent of human-made noise in the ocean, are largely unknown. Ocean noise monitoring efforts began post-industrialization, leaving baseline sound levels under which marine organisms evolved unclear. This study modeled primeval (wind-driven) ocean noise levels and modern (ship noise plus wind noise) ocean noise levels in the Santa Barbara Channel off Southern California. The modern noise levels were validated with acoustic measurements from two sites equipped with High-frequency Acoustic Recording Packages. There was good agreement between the modern noise level models when compared to measured levels for high frequencies, and at a site shielded by islands from long range sound propagation. The lower frequency acoustic environment, modeled at 50 Hz, was more degraded than the higher frequency noise levels, modeled at 1000 Hz. This model can be used to identify target regions and times for noise reduction efforts, as well as model future scenarios for noise reduction to identify techniques with the greatest potential for conservation.
The effect of flow rate on sonoporation within individual ex vivo mesenteric arteries
Authors: He Stephanie , Singh Davindra , Helfield Brandon
Published: July 2024

This study investigates the impact of vascular flow rate on the efficiency of sonoporation in viable mesenteric arteries ((391 ± 35) μm in intralumenal diameter), shedding light on the applications of ultrasound and microbubble-mediated (USMB) therapies. Isolated viable rat mesenteric arteries, which retained physiological functionality, exhibited reversible responses to vasoactive agents when mounted on a pressure myograph throughout the experiments. We then subjected these vessels to ultrasound (2.25 MHz) and microbubble treatment (Definity) under varied acoustic and flow conditions and assessed sonoporation through propidium iodide (PI) fluorescence microscopy. Results disclosed a strong correlation between microbubble flow rate, duty cycle, and sonoporation efficiency. Higher flow rates and duty cycles were associated with increased PI-positive cell counts, signifying more efficient cellular permeability. Post-treatment viability assays affirmed vessel integrity. These findings underscore the pivotal role of vascular flow rate in shaping therapeutic efficacy within individual vessels. The implications extend to refining USMB therapies in diverse disease scenarios, emphasizing the necessity for meticulous parameter selection to ensure both effectiveness and safety. Overall, the study furnishes valuable insights for enhancing the success and applicability of USMB-based therapeutic approaches in cardiovascular and oncological contexts.
Acoustic source characterization for chemical explosions in air
Authors: Kim Keehoon
Published: July 2024

Chemical explosions in the air generate large pressure disturbances. These pressure waves propagate as non-linear shock waves near the source and transition into acoustic waves in the far-field. Since low-frequency acoustic waves propagate long distances without significant loss of energy, acoustic signals induced by explosions are often used to determine explosion energies of the events in terms of an explosion yield. In order to estimate the explosion energy accurately, the relationship between acoustic energy and explosion yield must be understood. However, explosion yields are often measured by non-linear shock waves in the near-field, and it is not clear how much acoustic energy accounts for the explosion energy. In addition, acoustic signals typically have lower-frequency contents than shock waves in the near-field, and hence frequency-dependent explosion energy should be understood to accurately infer explosion yields based on acoustic observations. In this study, we investigate the relationship between acoustic energy and explosion yield based on ground-truth explosion data. A standard acoustic source waveform will be determined by acoustic observations, and frequency-dependent energy will be explored for yield estimation. We will demonstrate that this frequency-dependent acoustic source characterization can improve the accuracy and confidence of explosion yield estimation.
Electronic wind instruments for mobility-restricted musicians
Authors: Whalen David S. , Lowengard Henry , Braasch Jonas
Published: July 2024

One of the earliest applications of analog music synthesizers was the simulation of orchestral instruments. Electronic wind instrument sounds were played through piano-like keyboards or interfaces with breath controllers that mimicked physical wind instruments. Synthesizers are also often the best alternative for artists with disabilities to play a musical instrument. This talk focuses on methods and experiences the authors were involved with to design electronic alternatives to wind instruments for people who lost control of their arms. The Jamboxx is a USB controller that was specifically designed as a head-only interface using a breath controller to simulate airflow but also operates as a suck/puff device to activate menus and buttons, a slider to manipulate pitch, and a tilt-sensor to control expression parameters. The Jamboxx also addressed musicians seeking a harmonica-type interface to augment their guitar performance. The AUMI instrument is a touchless device based on camera tracking. This talk will address different sound synthesis methods to achieve realistic wind instruments, the ability to integrate these instruments with other off-the-shelf products (e.g., VST plugins), and special requirements for artists with special needs to play these instruments without too much fatigue. [Work supported by the Craig H. Neilsen Foundation.]
Sounding saxophones like flutes
Authors: Braasch Jonas
Published: July 2024

The saxophone can be modified with alternative non-single-reed tone generators, including double and free reeds and brass-instrument mouthpieces. It can also be played as a rim flute on the neck, which is a known extended technique for the saxophone. Flutes differ fundamentally from the other tone-generator types as they do not act like a valve, and their flutes are so-called open-open resonator instruments, while reeds and the lips in brass instruments effectively close one end of the resonator. As a practical consequence, all open-close hole key combinations result in fundamentally different pitches known from the regular saxophone. The fact that the saxophone is conically shaped, while the flute is typically cylindrical or inverse conical, further complicates the matter. Approaches to playing the saxophone as flute using alternative fingering combinations will be discussed along with measures of pitch accuracy, timbral, and level balance. While the achievable range aligns with many orchestral wind instruments, complex cross-fingerings make it difficult to play fast chromatic lines. The large bore of the saxophone gives the flute sound a dark character, more like a Native American flute or shakuhachi than a Western concert flute or recorder.
Phonon dispersion at long and short wavelength as seen by ultrasound and neutron spectroscopy
Authors: Hermann Raphael
Published: July 2024

Lattice excitations are fundamental energy carriers responsible for thermal transport in every solid. Whereas ultrasound spectroscopy typically probes these excitations in the kHz to MHz “sound” regime corresponding to mm to μm wavelengths, inelastic scattering of neutrons or x-rays probe the THz regime and Å wavelength. We will discuss a few examples of materials with peculiar sound and phonon properties, such as chiral α-TeO;2 and the AgSbTe;2-PbTe (LAST) solid solution. Analysis of resonant ultrasound data of α-TeO;2 requires the use of code that supports chiral space groups, such a RUSCal; intriguingly sound is extremely anisotropic, and in some directions the speed of sound is highly frequency dependent in the 0–1 THz range. LAST exhibits nanoscale inhomogeneities where the speed of sound is different in the matrix and the nanoinclusions. Work supported by the US Department of Energy (DOE), Office of Basic Energy Science (BES), and by Laboratory Directed Research at Oak Ridge National Laboratory; this research used resources at the Spallation Neutron Source a facility supported by DOE, BES, Scientific User Facilities Division. J. Torres, A. Flores-Bettancourt, M. Manley, B. Winn, G. Yumnam, I. Sergeev, P. Bauer-Pereira and A. Jafari are gratefully acknowledged for their collaboration.
Using resonant ultrasound spectroscopy to characterize thermally conditioned high explosive materials
Authors: Lum Jordan , Stobbe David M. , Mirkarimi Paul , Shaw William , Reinstein Henry , Lindsey Rebecca , Gee Richard
Published: July 2024

The ability to nondestructively quantify changes in mechanical properties of granular high explosive materials due to thermal conditioning is of importance for a myriad of civil and defense applications and could lead to better understanding of environmental aging-related effects for explosive material performance and safety. In this study, we report the first demonstration of using resonant ultrasound spectroscopy (RUS) to quantify the bulk elastic properties of granular high explosive materials at different bulk pressing densities and degree of thermal conditioning. Monitoring elastic property changes in granular explosive pressings has not yet been demonstrated using RUS, which is an appealing nondestructive characterization tool since it requires only dry point contact with the explosive material and can be applied to explosives with small form factors. Here, explosive material was studied in the form of binderized plastic bonded explosive pressings and unbinderized neat pressings, both of which are used commercially. Elastic stiffness coefficients calculated from the RUS measurements on the binderized and neat pressings show a significant increase for the post-conditioned samples compared to the pre-conditioned samples. This trend of increasing elastic properties with thermal conditioning was consistent for different density pressings and different thermal exposure conditions. [This work was performed by LLNL under Contract No. DE-AC52-07NA27344 and document release number LLNL-ABS-858868.]
Conversation behavior assessment to estimate communication difficulty
Authors: Klockgether Stefan , Simon Laurent S. , Derleth R. Peter
Published: July 2024

The communication behavior of humans adapts to the needs of different communication situations. Humans have developed several strategies to successfully communicate in challenging acoustic environments. Some of these strategies can be consciously controlled while in a conversation, but others happen sub-consciously, or as a mixture of both. The applied strategies come with an increased effort, a deviation from common behavior, or the overcoming of personal comfort zones and are usually ceased as soon as the situation allows. This study’s aim is to monitor participant’s communication behavior in easy and challenging acoustic situations and use this data as a measure for the experienced communication difficulty. The Sonova Real Life Lab allows to investigate natural conversation situations in a controlled acoustic environment. Participants can move around and interact with each other across a 25m² stage, while their head positions and orientations are tracked with a motion capturing system. The voices of the participants are recorded using wireless headset microphones. This allows to estimate individual vocal effort and analyze backchanneling and turn taking behavior. This contribution will present and discuss data collected with participants engaged in real one-to-one conversations, while the acoustic background was systematically altered.
Higher-order Non-Hermitian skin effect in an acoustic lattice
Authors: Jing Yun , Zhong Jiaxin , Benalcazar Wladimir , Kim Kevin , Oudich Mourad
Published: July 2024

Non-Hermitian physical systems offer a distinct band topology that gives rise to the interesting phenomenon known as the non-Hermitian skin effect (NHSE). However, the exploration of higher-order NHSE in classical wave systems by leveraging non-reciprocity has been largely unexplored. In this study, we introduce a novel approach to experimentally realize the higher-order NHSE in a two-dimensional non-reciprocal breathing acoustic Kagome lattice. This lattice is composed of acoustic cavities with non-reciprocal coupling achieved through electrically controlled active acoustic elements. We successfully observed second-order corner modes using a 3 × 3 lattice, which manifest as localized pressure distributions at specific frequencies in both parallelogram and triangular topological acoustic lattices. We delve into the underlying mechanisms and their implications, thereby paving the way for a deeper understanding of higher-order NHSE and potentially innovative applications rooted in the acoustic non-reciprocity.
A descriptive study of vowels in Dialects of Pakistani English
Authors: Yaqub Mumtaz , Khan Muhammad K.
Published: July 2024

The widespread use of English as a lingua franca has created many varieties of Global English. Pakistani English is an under-documented variety. As Pakistan is a multilingual country, it has been a difficult task for the linguists to document the dialects of Pakistani English and to determine how these dialects are influenced by regional languages (e.g. Pashto, Punjabi, Urdu etc.). Previous studies focused on Pakistani English of only a few locations (influenced by only a few regional languages). A broad-based study is required to document the phonetics of Pakistani English. The current study investigates two questions about the Pakistani English vowel system: how much variety there is, and whether the dialects of Pakistani English are influenced by regional languages. Speech data was collected from 208 undergrad students from thirteen cities representing thirteen regional languages of Pakistan (e.g. Lahore, Karachi, Peshawar etc.). Participants read thirty-two words expected to contain monophthongs in initial, medial and final position. Formant measurements are measured automatically in Praat. Preliminary analyses show variation in formant values of vowels in regional dialects; The results will allow for documentation of the vowel space of Pakistani English and will provide a broad representation of Pakistani English dialects.