bluuebunny/crossref_metadata_2025 huggingface dataset:
Separate emission/reception transducers for 3D ultrafast ultrasound imaging
Authors: Carrion Alexis , Touré Ibrahima , Krpic Tamara , Bilodeau Maxime , Masson Patrice , Quaegebeur Nicolas
Published: July 2024

Recent advancements in ultrafast 3D ultrasound imaging have revolutionized the field of echography, enabling its extension to novel applications such as cerebral dynamics, cardiac electrophysiology and the quantitative imaging of intrinsic mechanical properties of tumors. To facilitate these advancements, two primary transducer strategies are employed in 3D imaging. The first involves dense 2D probes equipped with a large number of elements, typically exceeding 1024. The second strategy uses row-column addressing, which simplifies the electronic control of the probe elements. Despite their effectiveness, these methods entail complexities in design and fabrication. Addressing these challenges, our study introduces an innovative transducer configuration that distinctly separates emission and reception functionalities. This separation not only simplifies the overall transducer design but also significantly reduces the system's complexity. A sparse array of PVDF transducers, which have been laser micro-machined to ensure acoustic transparency, is used at the reception. For the emission aspect, we employ a specialized acoustic concentrator to emulate point-like emission. The paper presents the detailed design requirements, assembly process, and the operational principles of this novel transducer. Furthermore, an experimental validation is conducted using a CIRS 040GSE phantom model. This validation is crucial to demonstrate the practical applicability and reliability of our transducer in real-world medical imaging scenarios.
Transmit beam design for tissue harmonic volume imaging of muscular tissues with a row-column array
Authors: Satarpour Maryam , Sheng Zhiyu , Cormack John M. , Kim Kang
Published: July 2024

Row-Column-addressed Arrays (RCAs), which have recently become commercially available, transmit along the rows and receive along columns of a 2D array in order to produce 3D volume images with low channel count. Imaging of the inherently three-dimensional, layered, and fibrous structure of muscular tissues in 3D using an RCA can improve evaluations of muscle function and disease compared to conventional 2D cross-sectional imaging, but volume images obtained using an RCA suffer from low lateral spatial resolution, low contrast, and grating lobe artifacts. Tissue harmonic imaging (THI) employs nonlinear acoustic effects to image at twice the transmit frequency, and can yield increased spatial resolution, increased contrast, and decreased artifacts from grating lobes. Here we investigate transmission considerations for THI in muscular tissues using a commercially available RCA (Vermon RC6gV). The parameter space is explored efficiently with frequency domain simulations of the 3D Westervelt equation. Pulse inversion imaging is applied experimentally using both steered plane wave and focused transmits to evaluate THI with an RCA in tissue phantoms and in muscular tissue. Pulse inversion volume images are compared to conventional images in terms of signal-to-noise, contrast, and ability to identify layers and fibrous structures in muscle in 3D. [Work supported by NIH HEAL Initiative R61AT012282.]
Design and construction of an in-air sonar for signal processing education
Authors: Dalton Kyle S. , Nelson Robert , Todd Steven J. , Warner Jonah , Hetherington Lily R. , Case John A. , Swann Mitchell J. , Kandias Constantinos S.
Published: July 2024

Sonar is an acoustic sensing method commonly used in underwater imaging and navigation. Students are often introduced to sonar theory, but few gain hands-on experience due to the cost and logistical difficulties associated with in-water experimentation. Alternatively, a sonar system can be designed for in-air use to mitigate some of the practical and operational challenges of acquiring sonar field data. Inspired by previous in-air sonar projects, the Pennsylvania State University student chapter of the Acoustical Society of America acquired $5,000 to construct an in-air sonar for exploring signal processing and mechanical design concepts. For a cost-effective solution, consumer audio equipment and additive manufacturing were leveraged. This presentation will walk through the sonar design and build process, discuss the project's current status, and present initial results. Plans for project development and potential inclusion into the curriculum will be discussed. Advice will be offered to those who may want to pursue similar projects.
Building a guitar amplifier: Accessible, engaging, and project-based audio instruction for students of all academic backgrounds
Authors: Thompson Benjamin R. , Smith Sarah R.
Published: July 2024

A challenge in designing first-year engineering curriculum is meeting the needs of a group of students with diverse academic backgrounds. Educators in the field of audio and acoustical engineering are often tasked with simultaneously preparing majors to be successful in their subsequent coursework while delivering a course that is both accessible to and exciting for all students. At the University of Rochester, we offer a survey course that introduces students to fundamental concepts in acoustics, signals, and audio electronics in which we leverage students’ existing experiences with sound and music in a project-based environment. Students complete a series of laboratory exercises where they interact with the science of audio by building a guitar amplifier circuit from scratch. Analyzing a schematic, soldering components, solving equations, seeing waveforms, and HEARING the results of their work, allows all students to engage in the content more deeply than any of these activities in isolation. In this presentation, we will share the specifics of our approach, and provide open-source curriculum in the form of lab manuals, supporting files, and sample PCBs.
A theoretical framework for estimating wind instrument bell reflection and transmission functions
Authors: Smyth Tamara
Published: July 2024

This work examines the bell reflection/transmission by using a combination of a piecewise waveguide model and an open-end reflection (along with the assumed amplitude-complementary transmission) function, modeled as a first-order shelf filter. The wind instrument bell is first modeled by deriving the chain scattering matrix for a piecewise cylindrical model, constructed using reflection coefficient vectors that have a useful structure of being interleaved with zeros (due to the round-trip delay of two samples in each section). The matrix is then used to yield the instrument (or instrument bell) transfer function which is shown to have both poles and zeros if the open-end reflection/transmission is made frequency dependent. If the open-end is modeled as a first-order filter and incorporated into the instrument model using matrix convolution, filter coefficients can be estimated from values in the reflection coefficient vectors that would otherwise be zero.
Acoustic measurements of full-scale electric vertical takeoff and landing aircraft
Authors: Lympany Shane V. , Page Juliet A.
Published: July 2024

The Advanced Air Mobility industry is progressing rapidly towards the goal of revolutionizing transportation by connecting urban and underserved communities with electric vertical takeoff and landing (eVTOL) aircraft. To achieve widespread use, eVTOL aircraft must generate acceptable noise in surrounding communities. Many eVTOL aircraft currently under development have novel configurations of rotors, propellers, and wings that may produce rotor-rotor and rotor-airframe interaction noise at certain flight conditions. Acoustic measurements of full-scale eVTOL aircraft are critical to understand the complex noise-generation mechanisms and to validate aeroacoustic models for these novel aircraft designs. In this presentation, we present acoustic measurements of Hexa, an 18-rotor, single-passenger eVTOL aircraft developed by LIFT Aircraft, Inc. We apply acoustic source characterization techniques using simultaneous acoustic measurements and vehicle telemetry data to provide a better understanding of the noise-generation mechanisms. One such analysis technique is the Vold-Kalman filter, which we apply to auralize the tonal waveforms of individual rotors. Finally, we discuss plans for upcoming acoustic measurements of a full-scale, multi-passenger eVTOL aircraft. These measurements and analyses provide the data and tools required to better understand the noise-generation mechanisms and to validate aeroacoustic models for full-scale eVTOL aircraft
Regional vowel patterns as shown by discrete cosine transforms
Authors: Thomas Erik R. , Mielke Jeff , Hazen Kirk A.
Published: July 2024

This project presents a new approach to analyzing geographical patterning in vowel variation that combines discrete cosine transforms (DCTs) with cluster analysis. It offers a means of reducing bias from analyses of geographical patterning in vowel variation. DCT0 and DCT1 capture the overall position of vowels in the vowel envelope and DCT2 adds information about curvature. To mitigate anomalies, these metrics are based on numerous tokens and measurement points. Cluster analysis can then be applied to the DCT data to indicate which speakers are most similar without predetermined groupings. The procedure suggests how vowel realizations are correlated with geographical divisions, if at all, within the area covered by a dialect survey. Here, we apply DCTs and hierarchical clustering to a corpus of speakers born 1970 or later and covering eastern Ohio, West Virginia, and western North Carolina. The results align only partially with isophones from earlier dialect surveys. Analyses of individual vowel phonemes typically exhibit considerable intermixture of forms; clearer geographic patterns emerge primarily when multiple vowels in named chain shifts are considered together. Recent dialect leveling appears to play a role in the paucity of distinguishable regional patterns.
Speech adaptation in conversation: Effects of segment cue-weighting strategy for non-native speakers
Authors: Zhang Han , Glover Morgan , Wang Fenqi , Deng Xizi , Behne Dawn , Jongman Allard , Sereno Joan , Wang Yue
Published: July 2024

Research has investigated how speakers make phonetic adaptations by adjusting their speech sounds to either converge to or diverge from their interlocutor’s. Less is known about the dynamic adaptive strategies non-native speakers use to improve intelligibility when interacting with native speakers, particularly how their strategies change over the course of spontaneous conversations. The current study examines phonetic adaptations in English words contrasting tense and lax vowels (e.g., sheep-ship) in unscripted conversations between non-native Japanese English and native English speakers during an engaging computer game task. Japanese speakers have previously been found to rely on temporal cues (vowel length) for tensity distinctions due to their L1 cue-weighting strategy rather than spectral cues (vowel quality) that are predominantly used in English. Acoustic analyses are conducted to examine changes in non-native vowel productions before, during and after the conversation task. We predict that, in an attempt to overcome miscommunication, non-native speakers may initially lengthen the tense vowels to distinguish them from their lax counterparts. As the conversation progresses, non-native speakers may adapt to a more native-like cue-weighting pattern by shifting to spectral distinctions. Results are discussed in terms of adaptations to cue-weighting strategies for intelligibility gains by interlocutors of different linguistic backgrounds.
Reciprocal sensitivity kernels for receiver positioning
Authors: Bottero Alexis
Published: July 2024

In their classical formulation, sensitivity kernels aim to evaluate the points where an infinitesimal variation in the properties of the medium would most affect a pressure (or displacement) measurement at a fixed location. These kernels feature typical cigar shapes, with characteristically low sensitivity on the direct path. In this presentation, the same approach is applied to the reciprocal problem, where we want to evaluate, at a constant source position, which points are the most (or least) sensitive to a given model change. These reciprocal kernels exhibit flared shapes centered on the areas where the model is perturbed. Applications to receiver positioning in acoustic are discussed.
Deep sediment characterization from very low-frequency features from merchant ships
Authors: Hopps-McDaniel Alexandra M. , Knobles David P. , Neilsen Tracianne B. , Wilson Preston S. , Hodgkiss William , Sagers Jason D.
Published: July 2024

The very low-frequency noise from merchant ships provides a good wideband source to study the deep layers of the seabed. The nested striations which characterize ship spectrograms contain unique acoustic features where the waveguide invariant (β) becomes infinite. This occurs at frequencies between 20 and 80 Hz where pairs of modal group velocities are equal. The goal of this project was to identify the β = ∞ frequencies in ship noise spectrograms and use these frequencies to perform statistical inference for the deep layer sound speeds and thicknesses. The Seabed Characterization Experiment of 2022 on the New England continental shelf had three vertical line arrays strategically placed between two shipping lanes. The average water depth was 75 meters with less than one meter bathymetry change between the arrays. The results of this study are based primarily on five ships. There was a gradual shift in the β = ∞ frequencies between the three arrays, suggesting a gradual change in the deep sediment layers. [Work supported by Office of Naval Research.]
Using acoustic energy of vocalizations to monitor population size and phenology of anurans
Authors: Lacio Callyan L. , Steinberg David S. , Simmons Andrea M. , Kloepper Laura
Published: July 2024

As a species that lives at the land/water interface, the American bullfrog (Rana catesbeianus) serve as a bioindicator in many habitats, yet also invasive in many locations. Due to challenges with traditional monitoring approaches, there is a lack of fine-scale population and phenological data for bullfrogs. Passive acoustic monitoring (PAM) can provide a low-cost alternative with high-resolution data for monitoring vocal animals. Sexually mature male bullfrogs attract mates by calling from exclusive territories. These vocalizations can be used to explore bullfrog behavior, population size, and phenology. We describe the analysis framework and initial results from an project monitoring the vocal behavior of frogs in 25 ponds in southeastern New Hampshire during the reproductive season using acoustic arrays. By using an acoustic energy index (RMS amplitude), we can estimate numbers of frogs in ponds, determine timing of reproduction, and even document anthropogenic disturbance. Our results can lead to future uses of PAM to monitor population size and phenology and develop reliable long-term management and conservation strategies.
Using bioacoustics to determine bird community patterns in a post-industrial city
Authors: Dennison Christopher , Buxton Rachel T. , Brown Katherine , Pearson Amber L.
Published: July 2024

Urban landscapes experiencing population loss often maintain high quantities of vacant land which cause social stress but also create opportunities for conservation of wildlife, including birds. Understanding how features of the urban environment affect bird communities is needed to support planning and policy that creates more effective biodiversity outcomes. Using acoustic recorders, we explored the factors that affect bird communities in Detroit, MI, based on features in surrounding neighborhoods. We compared Shannon diversity, richness, and acoustic detection of birds at 110 recording sites from 2021 to 2023. We used a generalized linear model approach to determine the moderating effect of variables including Normalized Difference Vegetation Index (NDVI) and density of vacant lots around recording sites on bird community space use. We found increased bird diversity at recording sites surrounded by higher densities of vacant land and evidence that some habitat specialists use these areas more than others. Our results indicate habitat preference for areas with more vacant lots, and general preferential habitat selection for certain features of the urban environment. Understanding how urban bird communities use space in a post-industrial, urban landscape will help inform more effective nature-based solutions and urban plans that balance conservation, health, and social justice goals.
Quantitative comparison of ocean soundscape model and measurements in the Atlantic outer continental shelf
Authors: Heaney Kevin D.
Published: July 2024

For 4 years, the Atlantic Deep Water Ecosystem Observing Network (ADEON), measured the acoustic soundscape using 7 bottom mounted landers off the coast of the South East United States (from Florida to Virginia). A shipping and noise model was built to generate regional sound maps, as well as to perform site-specific modeling for frequencies ranging from 20 Hz to 3150 Hz. The regional sound maps reveal that water depth is the key driver to local sound levels followed by the local geo-acoustic properties. It is predicted that the sound can be as much as 10 dB higher on the seafloor than at depths of 10 m. The site specific (where landers were deployed) model was run with a wide range of sediment uncertainty in the model, given our lack of knowledge of the sediment structure in water depths of 200 to 800 m deep, far from shore. A simple qualitative comparison of the soundscape measurements with the model provides immediate insight into the type of sediment at each lander position. Using this estimated sediment type, quantitative comparisons between the model and the data are made.
Doppler sonar records of fish movement through a strong tidal stream: 3-months of observations from Grand Passage Nova Scotia
Authors: Zedel Len , Hay Alex E. , Anderson Shane
Published: July 2024

Coastal passages with strong tidal streams present potential for renewable energy generation with in-stream hydrokinetic turbines. However, there are concerns that these systems will lead to environmental impacts when marine life interact with moving turbine blades. We explore measurements of fish movement using Doppler current profilers as a way of quantifying the frequency of such interactions. Fish are detected in Doppler sonar data using calibrated backscatter levels in each of the four acoustic beams; by reprocessing un-averaged data it is possible to extract both fish and water velocities independently. We analyzed three months of Doppler sonar data collected in Grand Passage Nova Scotia from September until December 2014. The data show fish detections in large numbers for only a few days on three occasions at the deployment site. Most of the observations show fish moving at the same speed as the water but there are times when there is significant difference in fish and water speeds.
Inverse design of arbitrary non-reciprocal acoustic dispersion in non-local phononic crystals and metamaterials
Authors: Khan Muhammad Bilal , Sugino Christopher
Published: July 2024

We present inverse methods to obtain arbitrary non-reciprocal dispersion relations in periodic, multi-degree-of-freedom lattices with non-local interactions. Just as phase-delayed interactions such as local resonance govern the frequency-dependence of a lattice’s dispersion relation, spatially non-local interactions govern the wavenumber dependence of the coefficients of the lattice’s characteristic equation. Thus, the use of fully general non-local interactions can, in principle, specify every branch of the dispersion diagram at every wavenumber. However, calculating a viable set of non-local interactions for a given set of desired dispersion curves is challenging, as there are multiple possible sets of coefficients that yield the same polynomial roots. To solve this problem, we first present a general method to calculate the dispersion relation of multi-degree-of-freedom non-local lattices, showing that non-local interactions create a Fourier series expansion that governs the wavenumber dependence of each matrix element. Next, we present numerical techniques to solve the inverse problem—i.e., given the desired dispersion relation, calculate the required non-local interactions—and discuss the associated computational challenges. Finally, we discuss practical methods to realize non-local interactions leveraging piezoelectric sensors and actuators, and we highlight how non-local interactions can be introduced in unit-cell based finite-element dispersion calculations.
Calculating the acoustic and internal gravity wave dispersion relations in Venus's supercritical lower atmosphere
Authors: Averbuch Gil , Petculescu Andi
Published: July 2024

There is a growing interest in quantifying Venusian seismic events through their infrasonic signatures detected by balloon-borne sensors at ∼ 55 km altitude. The extreme pressure and temperature at Venus’s surface correspond to supercritical conditions in the planet’s deep atmosphere. Therefore, an appropriate real-gas equation of state (EoS) must be used to study the acoustic properties and thermodynamics in the Venusian lower atmosphere. In previous work, the Peng-Robinson (P-R) EoS was used to obtain the acoustic sound speed and attenuation coefficient in the lower atmosphere of Venus. Here, the P-R EoS is coupled with the fluid dynamics equations in order to derive the acoustic and internal gravity wave (IGW) dispersion equations. Results show that in Venus’s deep atmosphere, the acoustic cut-off frequency corresponds to a period of ∼480 s (0.0020 Hz), and the buoyancy frequency corresponds to a period of ∼600 s (0.0016 Hz). By comparison, the values in Earth’s lower atmosphere are ∼310 and ∼340 s, respectively. These differences in acoustic and IGW propagation characteristics will be useful in later efforts to discriminate between the various waves detected by high-altitude sensors.
A study of acoustic array signal processing applied to tornado tracking
Authors: Frazier Garth , Liang Bin
Published: July 2024

In low signal-to-noise ratio (SNR) applications it is often necessary to integrate array measurement data over an extended temporal period to achieve satisfactory estimates of source bearings-of-arrival (BOA), especially in the case of multiple sources. For example, in popular frequency-domain methods such as MUSIC and its variants, the number of so-called snapshots (temporal windows) can be increased to improve performance. However, this improvement is achieved under the assumption that the bearing-of-arrival is not changing during the integration period. In this presentation, a study of the estimation performance of two algorithms (a MUSIC variant and a maximum-likelihood based method) is performed as a function of the number of snapshots, and the result of application of these algorithms to infrasound data recorded during the presence of tornadic storms (moving sources) is presented. Additionally, a method for integration over time using a moving source model is introduced.
Discussion of infrasonic detection of tornadoes in the Southeastern United States
Authors: Waxler Roger M. , Frazier Garth , Talmadge Carrick , Hetzer Claus , Buchanan Hank , Liang Bin , Thirunilath Naveen , Audette Chip , Hamama Islam
Published: July 2024

It has been established that tornadoes emit an infrasonic signal that is regularly detected in the 1 to 10 Hz band, although the actual band is expected to be wider. The physical mechanism through which this signal is generated is not yet fully understood and is the subject of current research. Here we discuss some of our experimental efforts, past and present. During the tornado seasons of 2017, 2018, and 2019, we deployed a network of infrasound sensor arrays in northern Alabama, southern Tennessee, and northwestern Georgia. We performed detailed analysis of one particular storm front that spawned at least eight identified tornadoes in northwestern Alabama during its passage. For that storm we find that when propagation modeling and wind noise analyses suggest that the signal should have been detected at a given array it always was. A long term monitoring effort is now underway in Mississippi. The Mississippi network deployment strategy relied on statistical analyses of tornado touchdown probability, signal transmission loss, and local wind noise studies. The network and array design for our Mississippi network was heavily informed by our experiences in Alabama and, we believe, represents the current state-of-the-art. In this presentation we will give an overview of what was learned from our previous deployments in Alabama, what strategies were used for the current deployment in Mississippi, and the current state of our data collection and analysis.
Physiological characterization of a macaque model of presbycusis
Authors: Kulkarni Swarat S. , Stahl Amy N. , Hackett Troy , Ramachandran Ramnarayan
Published: July 2024

Age-related hearing loss (presbycusis) is the leading cause of hearing loss worldwide, but current human studies do not separate this pathology from lifetime noise exposure. Laboratory macaques live in environments with minimal noise-induced hearing trauma and have long lifespans, making them optimal presbycusis models. We describe age-related auditory changes using two clinical, non-invasive physiological measures in aging macaques: distortion product otoacoustic emissions (DPOAEs) and auditory brainstem responses (ABRs). ABRs and DPOAEs were measured in anesthetized young (6–9 years old, n = 36 ears) and aging (26–35 years old, n = 20 ears) Macaca mulatta. ABR and DPOAE thresholds were elevated in aging subjects compared to young macaques at all tested frequencies. ABR thresholds were significantly correlated with age for frequencies >8 kHz, but DPOAE thresholds were not, a pattern likely attributable to a high-frequency ceiling effect for DPOAE measures. For frequencies <8 kHz, DPOAE thresholds showed significant correlation with age. However, this was not observed with ABR thresholds, suggesting differential sensitivity to age-related changes for auditory nerve and brainstem function compared to cochlear outer hair cell function. Ongoing analysis on temporal processing/adaptation metrics will further elucidate age-related changes. Future work will correlate these findings with histological analysis. [Work Supported by NIH R01-DC-015988.]
Comparing subjective similarity ratings and quantitative errors for the evaluation of free-field binaural panning techniques
Authors: Rusk Zane T. , Neal Matthew , Vigeant Michelle C.
Published: July 2024

A free-field sound source can be accurately rendered over headphones via direct convolution with head-related impulse responses (HRIRs). Using binaural panning techniques, a free-field source can be approximated, which can be thought of as HRIR reconstruction. However, a loss of fidelity occurs related to the panning algorithm’s spatial resolution. Previously, perceptual comparisons of noise bursts were made between panned sources and direct convolution with measured HRIRs. Reconstructions were generated using five different binaural panning methods, both with and without time-alignment of the HRIRs with separate application of the interaural time delay (ITD). To further explore the listening test results, the quantitative differences between the reconstructed and original HRIRs were investigated alongside the perceptual data. Several perceptually-motivated error metrics were evaluated, including errors in both ITD and interaural level difference. The fidelity of the reconstructed HRTF magnitude response was evaluated using metrics that leveraged auditory modeling steps. Both subjective and objective results support that HRIR time-alignment reduces the number of filters needed for high perceptual accuracy. A principal component-base rendering filter set produced the best subjective accuracy with only a small number of required filters (16-25). The ability to predict perceptually detectable degradation via quantitative errors will be discussed.
The project design includes a mass timber structure. Now what?
Authors: Clements Jessica S.
Published: July 2024

Mass timber comes with any number of acoustical design challenges depending on the project type and use. The many advantages in sustainability and cost mean that mass timber design is here to stay. As an acoustical consultant what does this mean for your project? This presentation will review some of the typical concerns you might have or questions to consider asking of the design team. We will review some typical pitfalls, touch on available resources, and discuss a few potential solutions to consider.
Cetacean presence and ambient sound level analysis in Bermuda: A comparison to historical records
Authors: Parry Dawn , Rouja Jean-Pierre , Klinck Holger
Published: July 2024

Marine Protected Areas (MPAs) are established to conserve nature while also preserving ecosystem services and cultural values. Many ongoing MPA discussions are centered on offshore islands, including Bermuda, a British Overseas Territory in the North Atlantic Ocean, which is currently assessing a management plan to protect 20% of its EEZ. Marine mammals are essential targets to monitor as part of effective MPA management because they are keystone species. In addition, as human activities raise ocean noise levels worldwide, monitoring ambient sound levels is essential to evaluating impacts on marine ecosystems. We collected nine months of passive acoustic data (at 250 kHz sampling rate and with 24-bit resolution) between December 2021 and September 2022, approximately 24 nm south of Bermuda, close to a location where previous studies were conducted in 1966 and 2013–2014. The cetacean presence and ambient sound levels derived from our dataset will be compared to these historical datasets. Our comparative analysis focused on humpback whales (Megaptera novaeangliae), fin whales (Balaenoptera physalus), minke whales (Balaenoptera acutorostrata), blue whales (Balaenoptera musculus), sei whales (Balaenoptera borealis), and beaked whales (family Ziphiidae). Results will illustrate how Bermuda’s offshore underwater soundscape has changed over nearly six decades.
Using sensors of opportunity to estimate the density of blue and fin whales
Authors: Seger Kerri D. , Harris Danielle V. , Miksis-Olds Jennifer
Published: July 2024

The “Combining global OBS and CTBTO recordings to estimate abundance and density of fin and blue whales”, or CORTADO project, is using data from two bottom-sensor types to implement a suite of methods for estimating density of fin and blue whales. While previous studies have demonstrated the utility of Ocean Bottom Seismometers (OBS) and Comprehensive Test Ban Treaty Organization (CTBTO) hydroacoustic data, the techniques have not yet been developed to the point where they can be routinely applied by the wider research community. The primary CORTADO goal is to provide a set of software tools and training materials to expand access and usability of large, historic datasets. This talk will focus on using the CTBTO sensors for estimating density with a bearing method. This technique uses the bearing of and the signal-to-noise ratio for each detected call to estimate how many animals are producing a set of calls at any given time over the detection range of the sensor at all bearings. Applying this tool to several CTBTO sensors, we can compare the amount of blue and fin whales over time as well as spatially across the northern and southern coverage areas of the sensor array.
Ultrasound propagation in cancellous bone: Dependence on mechanical, material, and structural properties
Authors: Wear Keith A.
Published: July 2024

Critical skeletal sites for osteoporotic fractures include femur and vertebrae. However, many ultrasound devices designed for the management of osteoporosis instead target the calcaneus, which is far more accessible to ultrasound than femur or vertebrae. Calcaneus-based devices have been shown to be very effective for predicting osteoporotic fractures of the hip. MicroCT-based finite element models support targeting of calcaneus based on similar biomechanical structure-function relations in calcaneus compared with femoral neck, greater trochanter, proximal tibia, and vertebra. Finite element analysis can be used to relate these mechanical properties to ultrasonic properties such as broadband ultrasound attenuation, speed of sound, and broadband ultrasound backscatter. As an ultrasound beam propagates through cancellous bone, it loses energy to absorption, longitudinal-shear scattering, and longitudinal-longitudinal scattering. The relative roles of these mechanisms can be demonstrated in phantom models.
Fast and accurate transcranial ultrasound simulation using the asymptotic model of the Civa Healthcare platform
Authors: Chatillon Sylvain , Drainville Andrew , Snell John , Moore David , Padilla Frederic , Lafon Cyril
Published: July 2024

To ensure its efficacy and safety, transcranial ultrasound therapy treatment planning requires accurate pressure field simulations and phase law corrections. Despite their long computation time and high memory usage, full numerical methods are often used since they are considered more accurate than semi-analytical methods. This work will present the so-called “pencil method“, a fast asymptotic model embedded in the CIVA HealthCare simulation platform. It allows computation in harmonic and impulse mode and the consideration of complex configurations, including solid obstacles, considering, at each interface, refractions and reflections with or without mode conversion of the acoustic field. This model was successfully compared to a recent collaborative work by Aubry et al. that presented a set of numerical benchmarks for transcranial propagation, to allow comparisons between various modeling tools. It was used to investigate the influence of parametric variation of skull material properties on the quality of acoustic focusing through the human skull. Its ability to predict the thermal rise at the intracranial target was validated against experimental data obtained ex-vivo through human skulls. Finally, works in progress will be shared about its connection to the open-source Kranion software developed at the FUS Foundation to facilitate comparison between clinical and simulated data.
Acoustic vaporization of perfluorohexane droplets is induced by heterogeneous nucleation at 1.1 MHz
Authors: Ramesh Rashmi , Thimonier Chloë , Desgranges Stéphane , Faugeras Vincent , Coulouvrat François , Laurent Justine , Marrelec Guillaume , Contino-Pépin Christiane , Urbach Wladimir , Tribet Christophe , TAULIER Nicolas
Published: July 2024

We investigated the ADV of perfluorohexane (PFH) nano and micro-droplets at a frequency of 1.1 MHz, at conditions where there is no superharmonic focusing. Our experiments were performed on suspensions of droplets in glycerol to avoid sedimentation. The ADV pressure threshold was defined as the pressure for which there is half a chance to observe a vaporization event. Our experiments showed that the threshold depends on the number of insonified droplets and the data were fitted by a statistical model, that is independant on the mechanism leading to ADV. The fit allows the derivation of the threshold in the case of a single insonified droplet. We further observed that the value of the ADV pressure threshold of a single PFH droplet decreases as its radius increases. In addition, at a constant droplet radius, the threshold did not vary when the PFH volume inside the droplet decreases, thanks to the encapsulation of an increasing number of water droplets. These results are incompatible with a model of homogeneous nucleation (where a nucleus can appear anywhere into the PFH volume). However, we developed a heterogeneous nucleation model, where the nucleus appears at the inner droplet surface, that successfully predicts our experimental ADV results.
Graduate acoustics at Brigham Young University
Authors: Gee Kent L. , Shepherd Micah , Anderson Brian E. , Neilsen Tracianne B. , Allen Matthew S. , Blotter Jonathan D.
Published: July 2024

Graduate studies in acoustics at BYU prepare students for industry, research, and academia by complementing in-depth coursework with publishable research. Coursework provides students with a foundation in acoustical principles, practices and measurement skills, including a experimental techniques and technical writing. Labs across the curriculum cover calibration, directivity, scattering, absorption, laser Doppler vibrometry, experimental methods for dynamic structures, lumped-element mechanical systems, equivalent circuit modeling, arrays, filters, room acoustics, active noise control, and near-field acoustical holography. Recent thesis and dissertation topics include active noise control, directivity, room acoustics, energy-based acoustics, time reversal, nondestructive evaluation, vibration and acoustics of aerospace vehicles, biomedical applications, flow-based acoustics, voice production, aeroacoustics, sound propagation modeling, nonlinear propagation, high-amplitude noise analyses, machine and deep learning applied to ambient noise level prediction, crowd noise interpretation, and underwater acoustic source localization, and ocean environment classification. Graduate students are expected to present research at professional meetings and publish in peer-reviewed acoustics journals. Graduate students often serve as peer mentors to undergraduate students on related projects and may participate in field experiments to gain additional experience. @BYUAcoustics
Optical method for direct temperature measurement of high intensity focused ultrasound heating
Authors: Oweis Ghanem , Daoud Hussein
Published: July 2024

The acoustic pressure field or heat deposition from the passage of an ultrasonic wave can produce a perceptible alteration in the medium’s optical refractive index. With proper placement of the light source and imaging camera, the optical effect can be recorded. This talk describes an optical temperature measurement methodology dubbed laser-ray-bundle (LRB) of the heat deposition from a high intensity focused ultrasound (HIFU) transducer in a transparent tissue phantom. The method does not require calibration, and directly converts the thermo-optic signal to temperature without recourse to any iterative computations. LRB boasts of excellent temporal and spatial resolutions and high temperature sensitivity better than any fine wire thermocouple. Furthermore, it is completely non-invasive. The LRB method is demonstrated with the heat deposition from single millisecond long HIFU pulses in a PDMS tissue phantom or from a train of single pulses with very good performance. The method represents a new capability for quickly assess a HIFU transducer output, and for laboratory and preclinical studies of heating near tissue interfaces including bone, air, or fat. A preliminary experimental setup for measuring the acoustic pressure field is presented.
Age and category structure in phonetic category learning
Authors: Heffner Christopher C.
Published: July 2024

When learning new speech sound categories in a second language, listeners must decide which sounds belong to the same category and which belong to different categories. This learning process is contingent on perceptual systems that change across the lifespan, which may, in turn, make certain categories easier to learn depending on which systems are employed by learners. In the present study, learners across a variety of ages categorize speech sounds taken from German that vary in their category structure (i.e., the complexity of the categories being learned within the stimulus space). Participants aged 7 to 70 are recruited and run at community sites such as museums and libraries. The preliminary dataset indicates that the simpler category structure saw strong age effects (with poorer performance on the younger and older ends of the age range and better performance at intermediate ages), while differences across ages were much smaller for the more complex category structure. These findings suggest that learning simpler category structures may rely on age-dependent learning systems, while learning more complex categories may rely on systems that are less age-dependent.
Quantitative assessment of English accent variation: Levenshtein distance and perceptual identification
Authors: Arzbecker Lian J. , Jacewicz Ewa
Published: July 2024

This is a perceptual study with a basis in acoustic phonetics. It investigates the extent to which accents of English can be quantified by the Levenshtein distance (LD), a string metric. LD defines string similarity by the minimum number of character edits required to transform one string into another. Narrowly transcribed speech samples of English provide the phonetic strings required for LD comparison. For the purposes of the current experiment, 24 speakers representing four English accent varieties are included: Midland American (control), British/Australian, Hindi-influenced, and Mandarin-influenced. High- and low-pass filters are used to augment or attenuate perceptual contribution of high- versus low-frequency information in the speech signal. Predictions stem from published correlations between LD and listeners’ perceptional ratings of intelligibility and native-likeness. For a group of monolingual American English listeners, confusion is expected between Midland American and British/Australian accents due to similarly low LDs, further intensified by low-pass filtering. However, fewer confusions are predicted between Hindi- and Mandarin-influenced English, due to varying L1 influences and the absence/presence of tonal information. This research seeks to explore accent perception, investigating the relationship between manipulated aspects of the speech signal and listener identification.
Perceptual representation of speaker gender in Spanish-English bilingual listeners
Authors: Merritt Brooke
Published: July 2024

The perceptual representation of speaker gender in monolingual English listeners has been found to be gradient and 2-dimensional. However, both gender expression and listener attribution of a speaker’s gender are known to vary by cultural and linguistic norms. Thus, listeners’ attribution of a speaker’s gender is expected to vary based on the cultural and linguistic practices of their community. This study examined the perceptual representation of speaker gender in Spanish-English bilingual listeners at the U.S./Mexico border of El Paso, TX. Twenty-four Spanish-English bilingual speakers of diverse gender identities (e.g., cisgender men, cisgender women, and transgender women) were audio recorded reading sentences from the English and Spanish versions of the Hearing in Noise Test. Nineteen cisgender Spanish-English bilingual listeners completed an auditory free classification paradigm, in which they classified speakers by perceived general similarity and gender identity in both Spanish and English conditions. Multidimensional scaling of listeners’ classifications in each language revealed that listeners organized speakers in a more expansive perceptual space in English (3 dimensions) as compared to Spanish (2 dimensions). Dimension weightings indicated that, in Spanish, listeners placed more emphasis on Dimension 1 as compared to Dimension 2 when classifying speakers, while, in English, listeners equally weighted the 3 dimensions.
Analysis of mid-frequency sound intensity fluctuations on the Washington shelf
Authors: Tang Dajun , Hefner Brian T. , Mickett John B. , Harcourt Ramsey R. , Xu Guangyu , Thorsos Eric I. , Prakash Kumar R.
Published: July 2024

A joint Oceanography/Acoustics experiment was conducted 15 July–13 August 2022 in Washington’s shallow coastal shelf waters to investigate mid-frequency sound intensity fluctuations and the oceanographic mechanisms driving them. Acoustic pulses centered at 3.5 kHz and 6 kHz were transmitted up-shelf from a stationary source and recorded by receivers on two moorings at 10 km and 20 km ranges. A ship-towed profiler, the Shallow Water Integrated Mapping System (SWIMS), repeatedly sampled the ocean between the source and receiver moorings, providing sound speed measurements as a function of range, depth, and time. In addition, five oceanographic moorings distributed along the acoustic path took additional ocean data over time. A roughly 15- dB ping-to-ping TL variability and scintillation index of near unity are found at the 20 km range. The intensity data show strong correlation between pings separated by a few minutes, beyond which it is uncorrelated. After smoothing, they also show trends at roughly 12-hour intervals. Assisted by environmental data and numerical modeling, the oceanographic mechanisms for these observed fluctuations are investigated. Implications for signal processing in the presence of such intensity fluctuations are also discussed. (Work supported by Office of Naval Research.)
Wavefield boundary interactions in a multi-domain environment—Experimental results
Authors: Swearingen Michelle E. , Taylor Oliver-Denzil , Lester Alanna , Stehno Abigail , White Michael J. , Woodley Christa , McKenna Mihan
Published: July 2024

Acoustic and seismic signals may be generated and received in land, air, and water domains within a multi-domain environment such as a littoral (nearshore) zone. As the energy moves between domains, the waves undergo complex transformations at the media boundaries. Separate consideration of each physical domain (land, air, water) leads to an incomplete understanding of the full cross-domain wavefield, leading to significant challenges in interpreting signals and creation of accurate models that realistically couple multiple domains. To address this knowledge gap, a team at the US Army Engineer Research and Development Center constructed a simplified, uniform levee to enable the measurement of signals that had passed through undisturbed boundaries. Sensor types were medium-specific, with microphones in the air, hydrophones in the water, and accelerometers in the soil. Using electric bridge wire detonators (EBW’s), impulsive signals were generated in each medium type and measured on sensors in all three media. This presentation begins with an overview of the experimental design, discusses the medium-specific measurement results, and concludes with a discussion of joint multi-domain data analysis results. Approved for public release: distribution is unlimited.
Rapid computation of steady state acoustic fields in heterogeneous and nonlinear media using the Acoustic Field Propagator
Authors: Cox Ben , Saha Ratan , Stanziola Antonio , Treeby Bradley
Published: July 2024

The Acoustic Field Propagator is a method for rapidly computing steady state complex acoustic fields in homogeneous media from spatially arbitrary single frequency sources. Here, an extension of the Acoustic Field Propagator to the computation of steady state fields in arbitrary heterogeneous, absorbing and nonlinear media, using nested iterations of the Convergent Born Series and a multi-frequency Helmholtz equation expansion, will be described.