bluuebunny/crossref_metadata_2025 huggingface dataset:
Application of the finite element method to atmospheric sound propagation over impedance discontinuities
Authors: Kirby Ray
Published: November 2022

Outdoor noise propagation typically involves the propagation of sound over mixed ground conditions, including variations in the surface impedance. Diffraction occurs at the interface between different ground conditions, and this can significantly affect local sound attenuation. Popular approaches to modelling impedance discontinuities include the boundary integral method, parabolic equations, and semi-empirical methods. This paper presents an alternative approach that takes advantage of the generality of the finite element method. It was shown recently that the semi analytic finite element method can be used to solve the exact governing wave equation for atmospheric sound propagation in a complex vertically stratified medium. This allows for the inclusion of arbitrary temperature and wind profiles provided the problem is range independent. It is shown here that it is relatively straightforward to extend this approach to include multiple surface impedance discontinuities, provided each discrete surface is uniform in the axial direction. This is achieved using point collocation to enforce the axial boundary conditions over each discontinuity. Predictions are generated for single and multiple discontinuities, and comparisons are made against predictions obtained using other computational methods.
Suppressing reverberation in cochlear implant stimulus patterns using time-frequency masks based on phoneme groups
Authors: Chu Kevin , Collins Leslie , Mainsah Boyla
Published: November 2022

Cochlear implant (CI) users experience considerable difficulty in understanding speech in reverberant listening environments. This issue is commonly addressed with time-frequency masking, where a time-frequency decomposed reverberant signal is multiplied by a matrix of gain values to suppress reverberation. However, mask estimation is challenging in reverberant environments due to the large spectro-temporal variations in the speech signal. To overcome this variability, we previously developed a phoneme-based algorithm that selects a different mask estimation model based on the underlying phoneme. In the ideal case where knowledge of the phoneme was assumed, the phoneme-based approach provided larger benefits than a phoneme-independent approach when tested in normal-hearing listeners using an acoustic model of CI processing. The current work investigates the phoneme-based mask estimation algorithm in the real-time feasible case where the prediction from a phoneme classifier is used to select the phoneme-specific mask. To further ensure real-time feasibility, both the phoneme classifier and mask estimation algorithm use causal features extracted from within the CI processing framework. We conducted experiments in normal-hearing listeners using an acoustic model of CI processing, and the results showed that the phoneme-specific algorithm benefitted the majority of subjects. [Work supported by NIH through Grant No. R01DC014290-05.]
High-temperature elastic moduli: A tool for understanding chemical bonding in thermoelectric materials
Authors: Zevalkink Alexandra
Published: November 2022

In the study of thermoelectric materials, the elastic moduli are valuable for predicting and interpreting trends in lattice thermal conductivity and some aspects of electronic conductivity (e.g., electron-phonon interactions). Because elastic moduli are highly sensitive to the details of chemical bonding, they can also be used to detect subtle changes in crystal symmetry or site-disorder due to phase transitions. Consequently, measurements of elastic moduli are of fundamental value in the development of structure-property relationships in thermoelectric materials. However, experimental reports of the elastic constants of functional materials are relatively sparse, and temperature-dependent data is even less common. Further, unlike most types of functional materials, thermoelectric materials are used over an extremely wide temperature range (up to 1300 K in some cases). In our lab, we measure the elastic constants of polycrystalline and single crystalline thermoelectric materials across a wide temperature range (250–1300 K) using resonant ultrasound spectroscopy with Al2O3 buffer rods to separate the transducers from the hot zone. In this talk, I will discuss the high-temperature elastic properties of several classes of thermoelectric materials, including Mg3Sb2 and GeSe-AgBiSe2 alloys, emphasizing the role that such data can play in interpreting composition- and temperature-dependent trends in lattice thermal conductivity.
On the combination of dynamic substructuring and surrogate modeling for the design and study of complex systems
Authors: Bonomo Anthony L. , Nguyen Dylan D.
Published: November 2022

For decades, dynamic substructuring approaches have been successfully utilized for the modeling and simulation of complex systems. More recently, surrogate modeling methods have emerged as a way to reduce the computational cost of simulating for design. This talk will introduce a paradigm in which these two techniques may be combined for the design and study of complex systems. For illustration, a simple example is put forward in which a mass-spring system is broken into subsystems and parameterized. The open-source Python package SMT (Surrogate Modeling Toolbox) developed and maintained by Bouhel et al. is used to construct surrogate models for each subsystem in which the component parameters are taken as inputs and the frequency response functions (FRFs) of the interface degrees of freedom are output. These FRFs are then used to construct the response of the fully coupled system by utilizing a dual Frequency Based Substructuring technique. In many real-world applications, this manner of calculating the effect of varying design parameters on the system response is likely more practical and computationally feasible than the alternative of directly simulating the coupled system response for many parameter sets and training a surrogate model from that output for further design space exploration and optimization. [Work supported by the Office of Naval Research]
A continuous system for testing fuzzy structure concepts
Authors: Ginsberg Jerry H.
Published: November 2022

Much effort had been devoted to studying fuzzy structure models in which the master structure is a large rigid body. At a time when activity in fuzzy structures began to wane, a paper by Drexel and Ginsberg [J. Vib. Acoust. 123, 181–187 (2001)] provided a quantitative model for testing the validity of assumptions embedded in the notion of a fuzzy structure. Its model was a cantilever beam with an finite number of attached SDOF oscillators. A state space formulation in conjunction with a Ritz series led to responses in the frequency and time domains. The investigation used idealized properties in which the attached SDOFs are positioned uniformly along the span and their fixed base natural frequencies are equally spaced around a center frequency that equals an isolated natural frequency of the beam. In addition, the natural frequency of each SDOF was taken to increase linearly with distance from the fixed end of the beam. The presentation will provide the details of the model and analysis, then highlight the similarites and differences of responses obtained from the models of the master structure as a rigid body and a cantilver beam.
A comparison between tongue dorsum configurations during vowel production in hypernasal speech vs typical speech
Authors: Hashemi Hosseinabad Hedieh
Published: November 2022

Appropriate nasalization is important for intelligible speech production and can be impacted by various disorders, including a cleft palate. Nasalization is achieved primarily through coupling the nasal and oral cavities by opening the velopharyngeal (VP) port, which introduces a variety of acoustic features. Although VP control has the primary role in nasalization, evidence suggests articulatory changes such as lip rounding (constriction) enhances acoustic features of nasality, while a downward and forward movement of the tongue dorsum in high vowels could attenuate perceptions of nasality in individuals with competent VP function. There is yet scant evidence to indicate whether such systematic changes occur in the case of VP opening. In an attempt to further understand the clinical aspect of this concept, we evaluated the tongue height and forwardness using ultrasound in three speakers with VP insufficiency (VPI) and three speakers with typical VP function to investigate the tongue configuration across two conditions. Tongue dorsum excursion and tongue positioning index were captured using Assistive Articulation Assessment (AAA) software during the production of vowels /a/ and /i/ across VCV contexts. Further results will be discussed in the meeting.
Cortical processing of speech in high-school students with different sleeping habits
Authors: shau Jefford , Yu Yan H.
Published: November 2022

Sleep plays a critical role on cognitive function especially in the developing brain. However, sleep duration and sleep timing are marked by individual differences. It is currently unknown whether and how sleep habits modulate speech perception in the developing brain. This study examined the correlation between sleep duration and brain responses to speech contrast in high-schoolers. A passive-listening oddball paradigm was used to deliver the speech contrast, and electroencephalogram (EEG)/Event-related potentials (ERPs) were used to collect cortical responses. Preliminary results indicated that there is a negative correlation between mismatch negativity responses and sleep duration in high-schoolers. The implication of the study will be discussed.
Acoustic comparison and speech-based biomarkers for the detection of gastroesophageal reflux disease: Research-grade versus iPad recordings
Authors: Aka David , Orbelo Diana M. , Pietrowicz Mary , Ishikawa Keiko , Yarlagadda Manoj , Buller Kevin , Kamboj Amrit , Leggett Cadman
Published: November 2022

Pietrowicz et al. (2022) demonstrated feasibility of detecting potential speech-based biomarkers to identify gastroesophageal reflux disease (GERD) and Barrett’s esophagus (BE); however, speech samples were obtained using research-grade recording equipment (TASCAM DR-40X with AKG C555L microphone). The use of more readily available equipment such as the Apple iPad with a native microphone could simplify data collection and allow access to a broader range of participants. Therefore, this study compared the research-grade recordings to iPad recordings for feasibility of detecting GERD and BE. One-hundred-fifty adults, clinically classified as GERD negative or GERD positive with or without BE, recorded a paragraph (The Rainbow Passage) simultaneously on both a TASCAM and iPad. Both data sets were analyzed manually for Alpha Ratio and Cepstral Peak Prominence (CPP) with Praat. Initial results show significantly higher alpha ratio and lower CPP in iPad recordings, indicating greater noise energy in the high-frequency range. Additionally, the capability of machine and deep learning model types to discern across GERD negative, GERD positive, BE, and normal voices were compared. Detection across these conditions and comparison of acoustic findings were explored to determine usefulness of the less controlled option of recording using an iPad with its internal microphone.
Rapid quantitative measure of speech intelligibility through personal protective equipment facemasks using two head & torso simulators
Authors: Rogers Daniel J. , Lee Nicholas
Published: November 2022

A test method has been developed that provides a rapid and quantitative measure of speech intelligibility via speech transmission index (STI) through personal protective facemasks using two Brüel & Kjær Head and Torso Simulators (HATS) under a variety of acoustical environmental conditions. STI measurements were made using this new Test Method (TM) on a collection of 3M prototype and production facemasks and respirators, a competitor facemask, and a “no mask” baseline. This new TM enables rapid differentiation among facemask designs. Comparisons among the set of face coverings shows a clear tradeoff of filtration level for STI. New 3M prototypes with 90% filtration achieved an Excellent STI of 0.85, only 0.03 below a perfect no mask baseline. There is a dramatic step from maximum STI with no filtration at all to Excellent STI with 90% filtration. Most of the 95% filtration masks had STIs clustered near the lower end of the Excellent band at 0.78. P100 filtration significantly compromised speech intelligibility in the 3M 6300 half facepiece reusable respirator with a Fair quality rating on the STI scale at 0.60.
Characteristics of infant-directed speech in caregivers with traumatic experiences
Authors: Welikson Bianca , Kondaurova Maria V. , Flowers Rebekah , Haynes Lora
Published: November 2022

Mothers with depressive symptoms interact differently with their children compared to mothers without depressive symptoms. Compared with non-depressed mothers, depressed mothers use a lower mean pitch and less extended pitch range, speak less, and respond slower to their infants. Are the characteristics of infant-directed speech (IDS) affected by a caregiver’s traumatic experiences? The study will examine characteristics of IDS in two groups of mothers (N=30); one group exposed to traumatic experiences and the other not exposed to traumatic experiences as assessed by the Adverse Childhood Experiences scale. The mean length of utterances (MLU, the number of morphemes per utterance), mean fundamental frequency (Hz), fundamental frequency range (Hz), speech rate (syllabus per utterance duration), and utterance duration (seconds) will be measured in maternal speech. Based on studies with depressed mothers, it is expected that mothers exposed to traumatic experiences will produce shorter MLU, lower fundamental frequency, less expanded fundamental frequency range, slower speech rate, and shorter utterance duration compared to mothers without traumatic experiences. The research will contribute to the development of early intervention strategies that will aim to strengthen language acquisition in children from families exposed to trauma.
The effect of a social robot mediator on speech characteristics of children with autism spectrum disorder
Authors: Shah Aamira , Kondaurova Maria V. , Pennington Robert , Welch Karla C. , Kuravackel Grace M. , Zheng Qi
Published: November 2022

Robot-mediated interventions have been investigated for the treatment of social skill deficits amongst children with Autism Spectrum Disorder (ASD). Does the use of a Nao robot as a mediator increase vocal interaction between children with ASD? The present study examined the vocalization and turn-taking rate in six children with ASD (mean age = 11.4 years, SD = 0.86 years) interacting with and without a Nao robot for 10 sessions, order counterbalanced. Each session lasted nine minutes. In the Robot condition, the robot provided vocal prompts; in the No Robot condition, children interacted freely. Child vocalization and turn-taking rate defined as the number of utterances/turns per second were measured. Results demonstrated that three children produced higher vocalization and turn-taking rates when a robot was present, and two when it was absent. One participant produced higher vocalization rates when the robot was not present, but more conversational turns when the robot was present. The findings suggest that the use of a Nao robot as a social mediator increases vocalization and turn-taking rates among children with ASD, but large individual variability is observed. The effect of the robot as a mediator on lexical diversity of child speech will also be investigated.
Effects of laryngeal vibratory asymmetry on voice acoustics and perception
Authors: Lee Yoonjeong , Reddy Neha , Chung Hye Rhyn , Zhang Zhaoyan , Chhetri Dinesh
Published: November 2022

Laryngeal vibratory asymmetry is commonly observed in many talkers, but its acoustic and perceptual consequences remain poorly understood. This study evaluates the relationships among vibratory symmetry, acoustic measures, and voice quality perception. We first test how the degree of left-right asymmetry in thyroarytenoid (TA) muscle activation relates to changes in voice quality as quantified by cepstral peak prominence (CPP). Using an in vivo canine phonation model, we stimulated each of the left and right TA muscles in a graded manner. Left-right asymmetry in vocal fold vibration was visually assessed, and CPP was measured from stable phonation. Results show that CPP is the highest at conditions of symmetric vibration and significantly decreases with increasing levels of asymmetry. In the subsequent audio rating experiment, 89 listeners ranked the phonation samples based on the quality (from worst to best). Overall, listeners prefer voices with higher CPP over those with lower CPP and voices with symmetric vibration over those with asymmetries. Results further reveal that listeners do not distinguish voices that fall within certain degrees of asymmetry. The relation between neuromuscular asymmetry and phonatory sound quality identified in this study has implications for clinical evaluation of the voice. [Work supported by NIH.]
Effects of spectral smearing on speech understanding and masking release in simulated bilateral cochlear implants
Authors: Cychosz Margaret , Xu Kevin , Fu Qian-Jie
Published: November 2022

Cochlear implants (CIs) have limited spectral resolution due to the number of activated electrodes and current spread in the cochlea, with ramifications for speech processing. Differences in degree of channel interaction across ears may partially explain variability in outcomes among CI users. This study explores how channel interaction impacts speech understanding in simulated cochlear implants. Speech recognition thresholds (SRTs) were measured in the presence of two speech maskers by 16 normal-hearing subjects listening to simulated bilateral CIs. Speech was delivered to both ears while maskers were delivered binaurally (diotic) or monaurally (dichotic). Stimuli were 16-channel sine-vocoded speech simulating 1) limited channel interaction in both ears, 2) limited channel interaction in one and broad in the other, or 3) broad channel interaction in both. Masking release was quantified as the SRT difference between diotic and dichotic conditions. SRTs were highest with broad channel interaction in both ears; when interaction decreased in one ear, SRTs improved, and improved further with limited interaction in both. Masking release was apparent across all conditions, but especially when the interaction was similar across ears (broad: 6.45 dB; limited: 6.51 dB). These results suggest that channel interaction may impact speech recognition more than masking release.
CCi-CLOUD: A framework for community based remote cochlear implant user experiments based on the CCi-MOBILE research platform
Authors: Younis Hazem , Hansen John H.
Published: November 2022

The speech processing field has recently developed a critical need for conducting listener experiments remotely versus traditional in-person methods due to social distancing measures enforced by COVID-19 pandemic. CCi-MOBILE is our current hardware research platform created to support the Cochlear Implant research community, facilitating the development of new strategies & algorithms for improving sound quality and scientific investigation for CI users/systems. In this study, CCi-CLOUD, a virtual platform, is proposed and developed to expand the functionality of CCi-MOBILE to allow for both subject testing and scientific studies to be performed remotely. CCi-CLOUD portal is established with three support categories: (i) Remote Desktop: with direct connect support for CI user remote experimentation; (ii) Cloud Data Storage: for data sharing among researchers & subjects; (iii) Online Web App: serves as a portal which connects CI subjects with the CI research community. Three multimodal sound experiments are considered in this study as a virtual experimental framework including speech recognition, speaker identification, and sound type classification for both CI and normal hearing (NH) users. Experimental evaluation is performed for both In-Lab and Remote/Online scenarios to benchmark experimental protocols and infrastructure validity for CI/NH subjects. Results on consistency between the two modalities are also discussed.
Direction of arrival estimation using Gaussian process interpolation
Authors: Gerstoft Peter , Hahmann Manual , Jenkins William F. , Michalopoulou Zoi-Heleni , Fernandez-Grande Efren , Mecklenbrauker Christoph
Published: November 2022

Gaussian processes (GP) have been used to predict acoustic fields by interpolating under-sampled field observations. Using GP interpolation to predict fields is advantageous due to its ability to denoise measurements, and for its prediction of likely field outcomes given a certain field coherence, or in GP terminology, a kernel. While there are many design options for a coherence function, in this study we examine using the radial basis function kernel, the physically based plane wave kernel, and a composition of plane wave kernels representing a certain angular interval of directions. The composite kernel is relevant in ocean acoustics where it is often the case that arrivals can only be within a narrow direction of arrival. We demonstrate that an array sampled with spacing larger than a half wavelength can benefit from GP interpolation, giving less root mean squared error.
Group conversation enhancement using distributed microphone arrays with adaptive binauralization
Authors: Mittal Manan , Sarkar Kanad , Corey Ryan M. , Singer Andrew C.
Published: November 2022

Hearing aids and other listening devices perform poorly in noisy, reverberant venues like restaurants and conference centers with numerous active sound sources. Microphone arrays can use array processing techniques like beamforming to isolate talkers from a specific region in the room while attenuating undesired sound sources. However, beamforming often removes spatial cues and is typically restricted to isolating a single talker at a time. Previous work has shown the effectiveness of remote microphones worn by talkers and adapting the signal at the earpiece to improve the intelligibility of group conversations. Due to the increase in hybrid meetings and classrooms, many spaces are equipped with high throughput, low latency devices including large microphone arrays. In this work, we present a system that aggregates information collected by microphone arrays distributed in a room to enhance the intelligibility of talkers in a group conversation. The beamformed signal from the microphone arrays is adapted to match the magnitude and phase of the earpiece microphones. The filters are continuously updated in order to track motion of both the listeners and talkers.
Broadband measurements and modeling of low-grazing angle bottom reflections from muddy marine sediments
Authors: Dall'Osto David R. , Tang Dajun , Dahl Peter H.
Published: November 2022

In 2017 and 2022, a series of experiments using explosive sound sources were conducted on the New England Mud Patch (NEMP), an area of the Eastern US Continental shelf defined by its thick muddy seafloor sediments. Broadband measurements from the near-bottom Intensity Vector Acoustic Recorders (IVARs) reveal resonant frequencies in the bottom reflected signals, which are excited at very low-grazing angles. A signal model based on a layered-bottom reflection coefficient is used to examine the geoacoustic properties of the marine mud, which leads to the conclusion that the sound-speed contrast across the water-mud interface (i.e. index of refraction, n) is less than one (n < 1), and also an increase in sound-speed occurs within the deeper mud-sediments (n > 1). Measurements in May 2022, replicating the same source and receiver locations from March 2017, also show resonances in the bottom-reflected signal. Differences between the two data sets (2017 and 2022) are primarily caused by the complex oceanography encountered during the spring-time measurements, absent during the isothermal winter conditions. Comparison of the two datasets examines the stability of the sound-speed contrast, including the effect of time-varying temperature at the water-mud interface.
Measurements of interface waves in the New England Mud Patch and estimation of the properties of the mud layer and underlying sand
Authors: Miller James H. , Potty Gopu R. , Lin Ying-Tsong , Hoyer Fin
Published: November 2022

The New England Mud Patch is a 13,000 square kilometer area south of Martha’s Vineyard and covered by a layer of fine-grained sediments. The water depth is about 70 meters. Below the mud is a sand layer with compressional sound speed of 1745 m/s. (Bonnel, et al., 2018) Scholte and Stoneley waves were generated by the Interface Wave Sediment Profiler (iWaSP), a piezoelectric bender beam transducer which vibrates the seabed. The iWaSP was deployed in experiments in 2017 and 2022 to generate these interface waves. These waves were received at ranges of 70 to 100 meters by bottom-mounted vertical axis geophones in 2017 and Ocean Bottom Recorders (OBXs) with 3-axis geophones and a hydrophone in 2022. The speed of these interface waves is about 90% of the shear wave speed in the elastic medium. Arrivals were detected on the geophones with speeds ranging from 100 to 200 m/s for a mud thickness of about 6 meters. It is hypothesized that these waves propagated on the mud-sand interface. Based on these results, this paper will comment on the properties of the mud layer. [Sponsored by the Office of Naval Research.]
High-resolution transdimensional geoacoustic inversion using autonomous underwater vehicle data
Authors: Sonnemann Tim , Dettmer Jan , Holland Charles W. , Dosso Stan
Published: November 2022

We invert reflection coefficient measurements of muddy sediment layers along a 12-km seabed transect on the Malta Plateau in the Mediterranean Sea using 1711 source transmissions recorded on a 32-element linear hydrophone array with both source and array towed by an autonomous underwater vehicle. Trans-dimensional Bayesian inference using reversible jump Markov chain Monte Carlo sampling is applied to obtain posterior probability densities of the number of homogeneous sediment layers, their depths, and their geoacoustic parameters. The forward sediment acoustics model is based on the grain-shearing model which obeys physical causality and provides correlation between important geoacoustic properties. Each dataset was treated as one-dimensional seabed structure inversion carried out on high performance clusters, and inversion results for multiple data sets were combined to yield a two-dimensional subsurface profile including full uncertainty analysis. Comparisons of inversion results to piston and gravity core estimates show agreement in both geoacoustic parameter values and depths of discontinuities. In the range-dependent model constructed from inverting the entire data set, dipping and terminating layers are observed along the track with high vertical resolution on the order of 10 cm.
Broadband sound speed and attenuation of a mud layer from acoustic propagation experiments in the New England Mud Patch
Authors: Wan Lin , Badiey Mohsen
Published: November 2022

A series of Seabed Characterization Experiments (SBCEX) have been conducted in the New England Mud Patch area, where a top mud layer overlays a sand sediment. Using broadband acoustic signals from the SBCEX, the sound speed and attenuation of the mud layer as a function of frequency (from a few tens of Hz up to around 1 kHz) have been estimated by various inversion algorithms based on (1) modal dispersion curves and transmission loss [reported at the ASA Spring meeting, 2016], (2) Airy phase [Spring, 2017], (3) modal amplitude [Fall, 2017], (4) spatial coherence measurements [Spring, 2018], (5) mid-frequency modal dispersion analysis [Fall, 2019], and (6) ground waves [Fall, 2022]. This paper summarizes these inverted sound speed and attenuation, which are obtained at various frequencies independently (without using the frequency dependent constraints from any geo-acoustic models), therefore the inverted results could be used to verify the validity of geo-acoustic models. The performances of these inversion methods are evaluated. The performance assessment is helpful for one to select appropriate inversion algorithms and to choose optimal acoustic data for geo-acoustic inversion. [Work supported by ONR Ocean Acoustics.]
Selecting a reference headphone for 3D audio reproduction
Authors: Olive Sean E.
Published: November 2022

3D audio uses generalized or personalized head-related-transfer-functions (HRTF) to provide the essential spatial and timbral cues. The headphone must reproduce these cues without introducing any errors of its own. A standard approach is to first calibrate the headphone by measuring and equalizing its frequency response at the blocked ear canal of the listener, or in the generalized case, a standard test fixture. However, the reliability of the calibration can be adversely affected by acoustical interactions between the headphone, the listener or the test fixture that can vary with headphone model, individual listener, and how the headphone is placed on their ears. The extent to which these errors affect the quality of 3D audio reproduction is not well understood. This paper discusses some recent investigations into the acoustical interactions between headphones, listeners, and standard test fixtures, and the effect on the quality of 3D audio reproduction through headphones. Several different models of headphones were measured on both human subjects and test fixtures with multiple placements to quantify the errors and their reproducibility. From these data, the headphone with the most linear and consistent response was selected for 3D audio reproduction.
Acoustic droplet vaporization for nonthermal ablation of brain tumors
Authors: Porter Tyrone M. , Peng Chenguang , Sun Tao , Power Chanikarn , Zhang Yongzhi , McDannold Nathan J.
Published: November 2022

Acoustic vaporization of perfluorobutane-based phase-shift nanoemulsions (PSNE) can be used to nucleate inertial cavitation (IC) in vivo. The acoustic pressure amplitude must exceed a threshold for vaporization of PFB-based nanoemulsions. Two focused ultrasound transducers with a center frequency of 837 kHz were oriented such that their focal volumes overlapped and the acoustic pressure amplitude was amplified. In this study, the dual transducer system was combined with circulating PSNE to nucleate IC in established brain tumors, leading to nonthermal ablation of the tumors. For comparison, microbubble ultrasound agents (UCA) were used as IC nuclei for ultrasound-mediated tumor ablation. The ablation volume was confined to focal volume when PSNE were used to nucleate IC, whereas pre-focal damage was observed when UCA were used as IC nuclei. Additionally, PSNE-nucleated IC ablated a larger percentage of the brain tumors on average than MB-nucleated IC (89.46.8% vs 11.17.7%, respectively). These results suggest that PFB-based PSNE may be used to significantly reduce the inertial cavitation threshold in the cerebrovasculature, and when combined with transcranial focused ultrasound, enable efficient focal intracranial nonthermal ablation.
Synergistic effects of microbubble-mediated focused ultrasound and radiotherapy in a F98 glioma model
Authors: Fletcher Stecia-Marie , Zhang Yongzhi , McDannold Nathan J.
Published: November 2022

Combined microbubble-mediated focused ultrasound (FUS) and radiation therapy (RT) has been shown to improve outcomes in tumors outside the brain. Here, we study the effects of FUS + RT in a F98 glioma model. Tumor cells were implanted into the brains of 45 Fischer rats (n = 4–8 per group): Controls, FUS, RT (4,8,15-Gy), and FUS + RT (4,8,15-Gy). 9 days after implantation, tumors were targeted using FUS (1–2 W, 220 kHz, 5 ms bursts, 1 Hz PRF, 180 s, 20 μL/kg Definity microbubbles), followed by RT. Tumor progression was monitored using MRI. At 4Gy, FUS + RT increased tumor doubling time by 11% compared to RT only and Controls (P < 0.01). At higher doses, where RT alone had a significant effect, there were no significant differences in doubling time compared to RT alone. Tumor volumes were reduced by 21–57% (4Gy) and 20–48% (15Gy) compared with RT alone (P < 0.05). No significant benefit was observed at 8Gy. A moderate, but not significant, increase in median survival was observed: 28 versus 27days (4Gy), 30 versus 29days (8Gy), and 35 vs. 33 days (15Gy). However, at 4Gy, FUS + RT significantly improved survival by 6% compared to the control group (median survival = 27days), while RT only offered no improvement. This study indicates that FUS + RT may improve therapeutic outcomes in glioblastoma, particularly at low RT doses, where RT alone has no therapeutic benefit.
Dynamic mode decomposition for underwater acoustics on autonomous platforms
Authors: Ryu Tony , Ali Wael H. , Lermusiaux Pierre F.
Published: November 2022

A sufficiently accurate representation of the ocean physics is needed for reliable underwater acoustics forecasting. Ocean physics are often simulated by high-dimensional data-assimilative numerical ocean simulations. Due to operational constraints such as computing, memory, communication-bandwidth, etc., it is infeasible to run these numerical simulations onboard the platforms. In this work, we employ the onboard data-assimilative incremental, Low-Rank Dynamic Mode Decomposition (iLRDMD) for forecast transmission, onboard computation, and data assimilation. The iLRDMD is an adaptive reduced-order model (ROM) that uses proper orthogonal decomposition (POD) and DMD for compression and transmission of high-fidelity ocean forecast to communication-disadvantaged platforms. It provides reduced-order onboard forecasting and also enables efficient updates of the DMD model itself from inputs from remote centers. Finally, when sparse observations are made by the platform, the iLRDM uses Bayesian data assimilation to correct both the forecasts and the DMD model. We demonstrate the use of deterministic and data-assimilative iLRDMD forecasted ocean fields for underwater acoustics computations in real ocean examples. We further explore the use of our adaptive ROM for joint reduction of the ocean physics and acoustics fields.
Improved acoustic situation awareness using reduced order models of ocean circulation
Authors: Hursky Paul , Coelho Emanuel F. , Lermusiaux Pierre F.
Published: November 2022

Acoustic situation awareness consists of knowing how far own sensors can detect other platforms and how detectable your platform is to their sensors. Since acoustic propagation is reciprocal, differences are down to source levels produced by each platform, transmission loss between them (reciprocal), the relative sensitivity of sensors, and the different directional noise observed at each platform. Noise fields are due to sources present both in the neighborhood (nearby ships) and in distant hubs (harbor shipping). Acoustic propagation models are used to predict transmission loss and received levels at all locations. Such models use sound speed for inputs. Platforms with limited communications can only be updated with the best available sound speed forecasts and measurements on a sporadic basis. We have developed reduced order models for sound speed, which consist of pre-loaded basis sets that capture anticipated ocean state fluctuations, for which very small (easily communicated) sets of coefficients can be used to reconstruct 3D and 4D ocean fields (sound speed and currents) on remote or edge platforms. We will present examples in the simulation of how our reduced order models contribute to improved acoustic situational awareness on such platforms.
Optimal stochastic modeling in random media propagation: Dynamically orthogonal parabolic equations?
Authors: Ali Wael H. , Mirabito Chris , Haley Patrick J. , Lermusiaux Pierre F.
Published: November 2022

Reliable underwater acoustic propagation is challenging due to complex ocean dynamics such as internal-waves and to the uncertain larger-scale ocean physics, acoustics, bathymetry, and seabed fields. For accurate acoustic propagation, capturing the important environmental uncertainties and variabilities and predicting the probability distributions of the acoustic pressure field is then what matters. Prior works towards addressing this goal include (i) wave propagation in random media techniques such as perturbation methods, path integral theory, and coupled-mode transport theory, and (ii) probabilistic modeling techniques such as Monte Carlo sampling and Polynomial Chaos expansions. Recently, we developed a novel technique called the Dynamically Orthogonal Parabolic Equations (DO-ParEq) which represent the sound speed, density, bathymetry, and acoustic pressure fields using optimal dynamic Karhunen-Loeve decompositions. The DO-ParEq are range-evolving partial and stochastic differential equations preserving acoustic nonlinearities and non-Gaussian properties. In this presentation, we showcase the theoretical and computational advantages of the DO-ParEq framework compared to the state-of-the-art techniques in the Pekeris waveguide and wedge benchmark problems, in addition to a realistic ocean example in the New York Bight region.
Working towards soundscape compatibility of indoor and outdoor shooting ranges with surrounding properties
Authors: Siebein Gary W. , Siebein Keely M. , Roa Marylin , Miller Jennifer , Siebein Gary , Vetterick Matthew
Published: November 2022

This paper explores methods to help make shooting ranges compatible with surrounding properties. Sounds from outdoor firing ranges can propagate over 2 miles from the range depending upon topography, vegetation, background sound levels, numbers of shooters, weapon types, and mitigation systems employed at the range. Many communities have regulations for maximum sound levels that can be propagated from one property to another. The impulsive nature of gun shots produces sounds that are not easily measured using conventional acoustical metrics and sound level meters. These items can be studied using three-dimensional computer models. Acoustical data for different weapon types are used as the sound sources. Mitigation options such as shooting sheds, berms, and other strategies can be studied as part of the design process to optimize sonic compatibility with neighboring properties. Similar processes are used for partially and fully enclosed ranges with the addition of the walls, roofs, doors, and HVAC systems for the range included in the models. An architect, engineer, and other design team members work to design specific systems to provide the required mitigation methods. Consultants can evaluate the cost of implementing the mitigation measures so that sonic compatibility is addressed prior to using the range.
Investigating infrasonic signal amplitudes at the lateral edges of propagation ducts
Authors: Green David N. , Nippress Alexandra
Published: November 2022

Azimuthal variation in expected infrasonic signal strength is often modelled using Nx2D finite-frequency acoustic propagation models. Such simulations frequently exhibit rapid changes in transmission loss (>30 dB across 5°) at the lateral edges of stratospheric propagation ducts, due to the sensitivity of acoustic ducting to the along-path windspeed. The inclusion of microbarometers in the USArray Transportable Array, with an inter-station separation of ∼70 km, has provided improved resolution across the lateral extent of tropospheric and stratospheric ducts within which infrasound is propagated over local and near-regional distances (10s to 100s km). We analyse signals from two explosions that generated infrasound across a broad swath of USArray microbarometers. Signals from the October 2012 Camp Minden Ammunition Plant explosion, Louisiana, show smoothly varying amplitudes across the stratospheric duct edge while those from the October 2011 Atchison Grain Elevator explosion, Kansas, exhibit less azimuthal variation. These signals provide a basis for comparison with current numerical modelling methods. Understanding infrasonic amplitudes at the lateral duct edge is important for both accurate signal interpretation from events of interest and for detection capability assessments of infrasound sensor networks. UK Ministry of Defence © Crown Owned Copyright 2022/AWE
Blackstock 9-3: Spherical waves, reflection, and attenuation
Authors: Simon Julianna C.
Published: November 2022

One of my favorite homework problems for waves in fluids or a general acoustics class is Blackstock 9-3, which involves a submarine positioned 50 m below the ocean surface and 500 m above the seafloor. The problem asks students to calculate the impedance of the seafloor given a frequency and known sound pressure levels received by the submarine after bouncing off the ocean surface or the seafloor. In part a, the calculation is made assuming a lossless medium and then in part b, using attenuation. The reasons this is one of my favorite problems are that it is real-world derived, combines many concepts, and requires understanding of wave propagation physics to solve; there is no simple equation (that I have found at least) that will immediately provide the correct answer. Students often struggle with what type of wave is emitted (plane versus spherical), then, if spherical waves, how to account for the boundary—especially on the seafloor where one must calculate the reflection coefficient. Every year this problem allows for good discussion in class and homework review sections.
But how does this work in the real world?
Authors: Haberman Michael R.
Published: November 2022

One common student critique of homework problems in lecture courses is that the complexities of the real-world are removed in order to create problems that reinforce a specific physical phenomenon or mathematical principle that is relevant to the content discussed in class. This tends to produce problems that are effective in teaching specific topics but may seem too distant from applications to provide an intuitive understanding of the subject matter. Fortunately, some topics in acoustics are very well-suited to use experimental data. This talk will highlight a selection of homework problems that make use of experimental data to illustrate physical principles covered in graduate courses in the acoustics program at The University of Texas at Austin. The first problem-set uses data from ultrasonic measurements to estimate the phase and group velocities in various materials and the second problem-set uses measurements of broadband exponential chirps played in a concert hall to estimate a range of performance metrics of the space. The talk will discuss how these exercises fit into the overall course structure, present student solutions and feedback, discuss learning outcomes, and make suggestions on how successfully integrate these kinds of problems into a lecture course.
Multi-electrode piezoelectric plates as non-reciprocal metamaterials
Authors: Schipf David , Le Peter , Guild Matthew D. , Yesner Gregory , Sieck Caleb F.
Published: November 2022

Non-reciprocal transmission of elastic waves through a solid is an exciting phenomenon that could open up new applications for elastic metamaterials. Non-reciprocal transmission of elastic waves can be achieved with spatio-temporally modulated boundary conditions. Some previous studies of non-reciprocal metamaterials have used uniformly modulated piezoelectric patches on metal host beams. Those beams have the advantage of electrically tunable boundary conditions due to the electro-mechanical coupling in piezoelectric patches, but are multi-material composites that are not easy to scale down. Instead, we show multi-electrode (patterned) piezoelectric plates, which are practical for a large range of geometric scales and frequencies, can exhibit non-reciprocal transmission with spatio-temporally modulated shunted circuits connected to the electrodes. In this work a study of sub-wavelength, ultrasonic band gaps that arise from shunted circuits on piezoelectric plates will be presented. The achievement of spatio-temporal modulation by using time-modulated capacitor-inductor circuits that vary in phase with their neighbors will be discussed. The results of frequency domain simulations of non-reciprocal transmission will be presented, and future directions for this research will be discussed. [Work funded by the Office of Naval Research.]
Perceptual training enhances Seoul Korean listeners’ use of vowel quality and pitch cues to English lexical stress
Authors: Tremblay Annie C. , Kim Hyoju , Dobbs Keira , Kim Sahyang , Cho Taehong
Published: November 2022

This study investigates whether high-variability (multi-talker) perceptual training is superior to low-variability (single-talker) perceptual training for enhancing Seoul-Korean listeners’ use of vowel quality and pitch cues to English lexical stress. Vowel quality and pitch are the two most important cues to English lexical stress in accented words (Tremblay et al., 2021). Seoul Korean does not have lexical stress, lexical pitch accents, or lexical tones. Seoul-Korean listeners completed a pre-/post-test sequence-recall experiment where they heard and recalled four English words uttered by different talkers. Experimental conditions: The words differed in lexical stress, which was cued by: (i) vowel quality, pitch, and duration; (ii) vowel quality and duration; (iii) pitch and duration; or (iv) duration. Control condition: The words differed in their initial consonant (Seoul-Korean contrast). Listeners completed one of two training types (8 × 30-mins). The words in the training followed a cue distribution that mimicked naturalistic spoken English (Im et al., 2018). Results: Both training types improved listeners’ recall for (i)–(iii), suggesting enhanced use of vowel quality and pitch. Learning gains were greater with high-variability training, but training type did not interact with cue. Thus, high variability provides a global rather than selective enhancement of listeners’ use of cues to lexical stress.
“Please say what this word is,” in the US and now again in the UK: Dialectal differences in a replication of Ladefoged and Broadbent (1957)
Authors: Stilp Christian E. , Chodroff Eleanor
Published: November 2022

One of the most famous speech perception studies is Ladefoged and Broadbent (1957), which demonstrated that acoustic properties of earlier sounds (in a context sentence) alter perception of subsequent sounds (in a target word). In their study, a context sentence with a lower first formant (F1) frequency promoted perception of a higher F1 in the target word, and vice versa. The decades since this seminal finding have seen myriad indirect replications, but none matched the incredibly large effect size of Ladefoged and Broadbent’s original study. Here, replication of Ladefoged and Broadbent (1957) was pursued using digitized versions of their original stimuli. Listeners were normal-hearing students in the UK (matching Ladefoged and Broadbent’s original sample) or the US (where most of the follow-up research has been conducted). Like the original study, perception of the target word shifted as a function of acoustic properties in the context sentences as in the example above. Perceptual shifts were larger for UK listeners than US listeners, but neither sample replicated the large effect sizes of the original study. While these results agree with Ladefoged and Broadbent’s conclusions, they invite consideration of how listener dialect and language background may relate to the magnitude of these effects.