bluuebunny/crossref_metadata_2025 huggingface dataset:
Examining the success of three kinds of cross-language similarity in predicting English listeners’ discrimination of Danish vowels
Authors: Bohn Ocke-Schwen , Garibaldi Camila L.
Published: November 2021

Several methods have been used in second language speech research to predict nonnative listeners’ discrimination of foreign language speech sounds. The present study examined how well three of these methods predict the discrimination of the four tightly spaced Danish unrounded front vowels by native listeners of Standard Southern British English (SSBE), whose four front vowels are evenly spaced along the close-open dimension. Experiment 1 examined the ecphoric similarity of the Danish and English vowels in a perceptual assimilation task in which L1 SSBE listeners used native labels and goodness-of-fit ratings in identifying the Danish vowels. Experiment 2 examined the perceptual similarity of the English and Danish vowels in a graded discrimination task in which the same listeners rated the degree of dissimilarity of Danish-English vowel pairs. The third prediction of discriminability was derived from an acoustic comparison of the Danish and English vowels in the F1/F2 space. The same participants as in Experiments 1 and 2 then discriminated three Danish front vowel contrasts. None of the three methods was found to fully successfully predict discrimination of the Danish vowels by the SSBE listeners. The presentation will discuss reasons for the lack of predictive power of the three widely used methods.
Learning non-native speech stop voicing as a result of exposure to foreign film
Authors: Hutchinson Amy , Dmitrieva Olga
Published: November 2021

While access to authentic input from native speakers is critical when learning to produce speech in another language (Flege et al., 1997; Flege etal., 1995; MacKay et al., 2001; inter alia), this option is not always accessible to all learners. With that in mind, this study explores how another type of naturalistic exposure, foreign film, can contribute to the development of L2 speech by specifically examining non-native stop voicing. To explore this research question, French speech shadowing data from naïve, monolingual English participants (n = 59) was collected before and after watching a short film in French. Collected productions were analyzed acoustically (voice onset time [VOT]) and through a series of AXB-style native French listener perceptual judgements (n = 221). While the acoustic analysis of VOT did not reveal a significant effect of film on duration when compared to a control group (n = 15), native listeners perceived post-film exposure productions to be significantly more target-like than pre-film exposure productions. This finding suggests that although VOT was seemingly unaffected by foreign film exposure, participants adjusted alternative acoustic correlates of voicing and that these modifications were perceptible to native listeners. This ultimately provides evidence for the effectiveness of foreign film exposure in non-native speech learning.
Large whale surveys off Southern California using passive acoustic gliders
Authors: Mellinger David K. , Fregosi Selene , Ampela Kristen
Published: November 2021

A passive acoustic survey off Southern California was conducted using gliders measure the distribution of several baleen whales and sperm whales. Two gliders were flown to estimate the occurrence of blue, fin, humpback, minke, and sperm whales in over the continental shelf, shelf slope, and deep waters offshore of the shelf slope up to 350 km from shore. One glider malfunctioned shortly after deployment and had to be recovered; the second followed its desired ∼1200 km trackline over 54 days. Whale vocalizations were detected using a mix of automated and manual tools. Fin whale sounds were detected every day, and humpback whale sounds were detected frequently but more sporadically, along the route, particularly over the continental shelf. Sperm whale sounds were detected episodically over deep (>2000 m) waters and briefly on the shelf. Blue whale sounds were detected on three days over the shelf, and minke whale sounds were not detected at all. [Funding from Navy NAVFAC.]
Acoustic differentiation and classification of wild belugas and narwhals using echolocation clicks
Authors: Zahn Marie J. , Rankin Shannon , McCullough Jennifer L. , Koblitz Jens C. , Archer Frederick , Rasmussen Marianne H. , Laidre Kristin L.
Published: November 2021

Belugas (Delphinapterus leucas) and narwhals (Monodon monoceros) are highly social toothed Arctic cetaceans with large vocal repertoires and similar acoustic profiles. Passive Acoustic Monitoring (PAM) that uses multiple hydrophones over large spatiotemporal scales has been the primary method to study their populations, particularly in response to rapid climate change and increasing underwater noise. This study marks the first acoustic comparison between wild belugas and narwhals from the same location and reveals that they can be acoustically differentiated and classified solely by echolocation clicks. Acoustic recordings were made in the pack ice of Baffin Bay, West Greenland during 2013. Multivariate analyses and Random Forests classification models were applied to eighty-one single-species acoustic events comprised of numerous echolocation clicks. Results demonstrate a significant difference between species’ acoustic parameters where beluga echolocation was distinguished by higher frequency content. Classification model predictive performance was strong with an overall correct classification rate of 97.5% for the best model. The most important predictors for species assignment were defined by peaks and notches in frequency spectra. Our results provide strong support for the use of echolocation in PAM efforts to differentiate belugas and narwhals.
Resident autonomous underwater vehicles for persistent mobile ocean observing
Authors: Manalang Dana
Published: November 2021

Whether near shore or in the open ocean, stationary ocean observing systems lack the ability to respond spatially to transient and difficult-to-predict phenomena, such as mid-ocean ridge eruptions, instabilities in methane hydrate deposits, turbidite flows, sea–ice interactions, mass wasting events, or changes in coastal currents. Detecting and characterizing these types of events and the processes driving them requires mobile systems available at the time of the event onset. Ideally, mobile autonomous underwater vehicles (AUVs) would permanently be stationed in or near areas where events of interest are likely to occur. Traditionally, due to their dependence on batteries, AUV mission durations are often measured in hours and require costly on-water support vessels and human intervention, making it impractical to sustain a mobile observing presence. However, advances in cabled power/comms and renewable marine energy technologies present significant opportunities for developing persistent mobile subsea systems able to recharge their batteries from fixed underwater infrastructure. In addition to power, these “resident” AUVs will require navigation and data transmission support. Acoustic systems will play key roles as sensing systems, navigation, vehicle homing, data transfer, and advanced robotic operations. This talk will present an overview of the systems and concepts relevant to subsea mobile ocean observing systems along with example applications.
Non-planar holographic lens for mild hyperthermia in a broad area
Authors: Ghanem Mohamed A. , Maxwell Adam D. , De Koninck Lance H. , Bailey Michael R. , Averkiou Michalakis A.
Published: November 2021

High intensity focused ultrasound (HIFU) has been used as a non-invasive tool for thermal ablation treatments. Typically, HIFU can ablate a small region (2 × 10 mm2) depending on the frequency and transducer dimensions. Cavitation-induced bubbles or injected microbubbles have been shown to enhance tissue heating during HIFU at lower acoustic intensities. The formed lesion is limited to the focal region, necessitating prolonged time of treatment to expose the entire target. To solve this problem, we designed a non-planar diffraction lens that mounts onto the surface of a 900kHz focused transducer (64 mm diameter and 62 mm focus) to enlarge the focal region. The lens was designed with an iterative angular spectrum approach to achieve a lateral beamwidth of 8 mm while maintaining a similar axial beamwidth. The focal beam size (transverse × axial) increased from 2.5 × 15.8 mm2 to 8 × 20 mm2 which also resulted in a corresponding increase in thermal lesion. We plan to expand this work to matrix phased arrays for application to mild hyperthermia for enhanced drug delivery.
Acoustic isolation of cabinets on walls with resilient channels
Authors: Raley Michael
Published: November 2021

Single-stud walls (wood or steel) with resilient channel are commonly used to provide acoustic isolation for apartments and hotel rooms. In apartments, kitchen cabinets are often mounted on demising walls and/or corridor walls where resilient channel is also being used. In hotels, heavy items such as headboards, nightstands, and desks are often mounted to the demising walls. It is often impossible to entirely avoid mounting items on the side of the wall with resilient channels. Commonly, contractors will attach plywood directly to the studs between the resilient channel to fill the void created by the resilient channel, and the cabinets or other heavy items are screwed through the gypsum board and into the plywood, completely short-circuiting the isolation provided by the resilient channel. This presentation provides laboratory test results showing the detrimental effects of this mounting method. The presentation also introduces a new method of mounting cabinets (and other heavy items) that maintains the acoustic isolation of the resilient channel. Laboratory test results for the new mounting method are included and they show that the overall acoustic performance (STC rating) of the wall is maintained when cabinets are mounted.
Towards 3D selective manipulation of cells and microparticles with spiraling holographic interdigitated transducers
Authors: Baudoin Michael , Gong Zhixiong
Published: November 2021

In previous papers [Baudoin et al., Sci. Adv. 5, eaav1967 (2019); Baudoin et al., Nat. Commun. 11, 4244 (2020)], our team demonstrated the possibility to trap and manipulate microparticles and cells selectively, in 2D and in a standard microfluidic environment with some spiraling interdigitated transducers (S-IDTs). These S-IDTs were designed as the phase hologram of specific wave structures called focused acoustical vortices. Here we explore theoretically with an angular spectrum code the 3D trapping capabilities of these transducers. We demonstrate: (i) that the field synthesized by S-IDTs creates a 3D radiation trap for microparticles and cells and (ii) that the trap can be moved axially by simply tuning the driving frequency. This work opens perspectives for 3D manipulation of cells with single beams acoustical tweezers.
Investigation of the effect of chip material on acoustofluidic microparticle manipulation
Authors: Açıkgöz Hande Nur , Karaman Alara , Şahin Mehmet Akif , Çaylan Ömer , Büke Göknur Cambaz , Yıldırım Ender , Çetin Barbaros , Özer Mehmet Bülent
Published: November 2021

Ultrasonic particle manipulation in microchannels is a rapidly growing research field with significant potential applications in biological studies. Several factors are essential in achieving effective manipulation, such as obtaining resonance conditions in the actuator, chip, and/or the microchannel. The choice of chip material is an important design parameter since it has significant implications on acoustic performance, thermal performance, stability, ease of manufacturing and the overall cost of the acoustofluidic separation unit. Even though different materials are employed in acoustofluidic studies, most studies implement silicon as the chip material due to its superior acoustic properties. On the other hand, silicon has a complicated manufacturing procedure that requires cleanroom facilities. Therefore, from the manufacturing perspective, it is beneficial to use materials that enable mechanical machining. In this study, for the first time in the literature, we have compared the performance of acoustofluidic chips manufactured from silicon, glass, PMMA (polymethyl methacrylate) and PDMS (polydimethylsiloxane) materials in a comparison study. Furthermore, we propose using a new composite material, FR4, which seems to possess favorable acoustic properties of acoustically hard materials (such as silicon and glass) and the ease of manufacturing of acoustically soft materials such as polymers.
Top-down attention modulates neural responses in neurotypical, but not ADHD, young adults
Authors: Kwasa Jasmine , Noyce Abigail , Shinn-Cunningham Barbara
Published: November 2021

Individuals differ in their ability to selectively attend to goal-relevant auditory stimuli. People with Attention-Deficit/Hyperactivity Disorder (ADHD) in particular tend to show cognitive deficits associated with inhibition and attention. We hypothesized that people with ADHD would exhibit poorer performance and weaker neural signatures of attention when undertaking a challenging auditory task that required strong top-down attentional control. Neurotypical (N = 20) and ADHD (N = 25) young adults with normal hearing listened to one of three concurrent, spatially separated speech streams and reported the order of the syllables presented while we recorded electroencephalography (EEG). We tested both the ability to sustain attentional focus on a single “target” stream and the ability to monitor the target but flexibly switch attention to an unpredictable “interrupter” stream from another direction if and when it appeared. In both groups, the interrupter evoked larger neural responses when it was to be attended compared to when it was irrelevant, including for the P3a “reorienting” response previously described as involuntary. This attentional modulation was weaker in ADHD listeners, even though their behavioral performance was no lower. Additionally, individual performance correlated with the degree of top-down modulation of neural responses. These results demonstrate that listeners differ in their ability to modulate neural representations of sound based on task goals.
Discussion on harmonic scattering of A0 wave from a local nonlinear damage—A numerical study
Authors: Ghodake Pravinkumar R.
Published: November 2021

In nonlinear ultrasonics, the interaction of waves with uniformly distributed damages in metallic plates is very well studied through different theoretical, computational, and experimental studies. But in practice, highly local damages such as micro-cracks, and local plasticity are introduced in plates. This motivates to get more detailed insight into the harmonic scattering of A0 waves from early-stage local damages. To investigate the harmonic scattering from local damage in plates, numerical studies (FEM) are carried out. Local damage is modeled as the Murnaghan model for aluminum at the center of the spatial domain by avoiding linear impedance mismatch between linear and nonlinear regions. Harmonic scattering due to monochromatic A0 wave input is captured successfully. Higher harmonics of backscattered and forward scattered displacements noted at the plate surface are observed. The separation of second harmonics from primary mode due to group velocity mismatch is not observed as the local damage sizes are relatively short (5i–20 mm). One-way and two-way two-wave mixing with group velocity mismatch studies shows sum, difference, and higher harmonics along with mode conversion of both the backscattered and forward scattered waves. Higher harmonics of the harmonically scattered waves are highly sensitive to damage size and intensity of damages.
Voice quality differences in Dunan: Links between gemination and fortis-lenis contrasts
Authors: Lau-Preechathammarach Raksit T.
Published: November 2021

The fortis-lenis contrast is traditionally defined by “articulatory force” and correlates with a host of measures, including closure duration, f0, amplitude, VOT, open quotient, and spectral tilt (Kohler & Dommelen, 1987; Cho et al., 2002). These measures are also features of voice quality (Keating et al., 2011; Brunelle et al., 2020) and gemination contrasts (Idemaru & Guion, 2008; Kraehenmann, 2011), and gemination has been suggested to be a type of fortis-lenis distinction (Ladd & Schmid, 2018). The current study explores acoustic correlates of initial /T K/ vs. /t k/, a contrast variably termed as initial gemination or fortis/lenis, in Dunan, a highly endangered Southern Ryukyuan language (Bentley, 2008; Yamada et al., 2015). Audio from fieldwork sessions with an elderly speaker were aligned with the Montreal Forced Aligner (McAuliffe et al., 2017) and measures of /T K t k/ and the following vowel were taken. The contrast is cued not only by closure duration and VOT, but also by f0, amplitude, H1*-H2*, H1*-A3*, and CPP differences that persist over the following vowel. This naturalistic data contributes to evidence for a constellation of acoustic features shared between fortis-lenis, gemination, and voice quality contrasts that may point to commonalities in laryngeal configuration.
Acoustic correlates of gender identity in American English speech
Authors: Zhou Chen , Bishop Jason
Published: November 2021

A recent study with native German speakers finds that acoustic properties of speech associated with biological sex may also vary within-sex as a function of gender identity, defined gradiently along continuous scales of self-reported masculinity/femininity [M. Weirich and A. P. Simpson, “Gender identity is indexed and perceived in speech,” PLoS One 13(12), e0209226]. In particular, Weirich and Simpson find that men who rate themselves as more feminine produce speech with somewhat more female-like characteristics, such as higher mean f0 and larger vowel space area (VSA) relative to men who rate themselves as less feminine. In the present study, we investigate whether such gradient measures of gender identity have a comparable relationship to acoustics in American English. Recordings of read speech produced by 74 native speakers from metropolitan New York City (38 females, 36 males) were analyzed with respect to VSA and spectral properties of the sibilant fricative /s/. Gradiently defined gender identity was, as in Weirich and Simpson (2018), estimated for all speakers using two established measures of self-reported femininity. We report findings related to VSA and /s/ for both male and female speakers, and discuss the implications for the role of sex and gender in phonetics research.
Influence of clear speech on F0 patterns of Mandarin lexical tones
Authors: Rittenberry Jack W. , Shport Irina
Published: November 2021

When communication becomes difficult, a talker may take on a form of communication known as clear speech (Keerstock & Smilijanic, 2019; Picheny et al., 1985). Little is known, however, about clear-speech modifications in tone languages (Zeng, 2017). This study showed how native Mandarin speakers modulate F0 in tone words through increased variation, raised F0 onset and offset. Participants read twenty-four sentences varied in four target tones, three times. Sentences were presented in two blocks: casual speech condition (as if talking to friends) and clear speech condition (as if communicating to someone with hearing loss). Data analysis of seven speakers suggested that effects of clear speech on F0 contours were tone-dependent. As compared with casual speech, in clear speech, F0 contours of high level (T1), mid-rising (T2), and high-falling (T4) tones were higher within the same tonal context; in contrast, F0 contours of the low-dipping tone (T3) were lower preceding T1 and T4. F0 range, onset F0, and offset F0 were greater in clear speech mode across most tonal environments. Additional data of eleven speakers has been collected to examine preliminary results and discuss findings in terms of signal-enhancement in clear speech production of lexical tones.
Prosody and the interpretation of English relative clauses
Authors: Fenton Elyssa
Published: November 2021

This study investigates the prosodic cues involved in the disambiguation of English relative clauses (RCs). For example, in the sentence “The reporter interviewed the daughter of the senator who was controversial,” the underlined RC can modify the higher noun “daughter” or the lower noun ‘senator, thus having a high attachment (HA) or low attachment (LA) interpretation. Prior work shows that prosody influences the interpretation of ambiguous structures (Lehiste, 1973; Nespor & Vogel, 1983) but does not examine specific acoustic cues distinguishing between RC interpretations. An elicited production task was conducted involving 40 target HA and LA RCs. Intermediate boundaries at the higher and lower nouns were examined for prosodic phrasing cues including pauses, syllable lengthening, boundary tones, and final creak. Delaying of prenuclear peaks was also considered. Data from 8 speakers show that 70% of HA utterances contained two intermediate boundaries, compared to 57% of LA utterances. Main results show that the majority of first intermediate boundaries were high (H-) (81% for LA, 70% for HA), while second intermediate boundaries were usually low (L-) (78% for LA, 73% for HA). In addition, LA interpretations had prenuclear delayed peaks on the higher nouns more often (50% vs. 36% of HA cases).
Software best practices
Authors: Lee Wu-Jung
Published: November 2021

Software tools play an increasingly important role in modern day acoustics research. We will share a few core software best practices and tools that can help make research processes and outcomes more reproducible and at the same time facilitate collaboration. We plan to cover coding best practices with emphasis on tests and documentation, which contribute to code that is more reusable and robust to errors. We will also cover the use of code and data repositories for collaborative research and show open cloud-based platforms suitable for sharing research outcomes. We will conclude the tutorial by an open discussion on the practicalities of these guidelines and invite all participants to share their perspectives and experiences with the group. The tutorial will include presentation, demos and hands-on exercises, so please bring your laptop to the tutorial.
Spaces for recording and production in the streaming age
Authors: Mayell Marcus R. , Perez Tim , Giegold Carl P.
Published: November 2021

The creation, curation, and publication of recorded audio/video content is no longer restricted to professional recording studios and production entities. More accessible and affordable means of audio/video capture, broadcasting, and distributing (primarily through streaming and web-based methods) have given increase to the prominence of self-produced content. The expectations and demands for recording equipment and environments in an era of increasing on-demand and self-op functionality lead to a new set of design parameters. For spaces like these, complex technological and architectural systems are often required for seamless, uninterrupted, and unhindered content capture and delivery. For other spaces, such as Guarneri Hall in Chicago, the architectural and technological designs meet the needs of both high-quality audio/video recording and live streaming alongside a live “in-room” audience – all achieved within a straightforward design approach and constrained budget. This paper will focus on emerging space types which are designed to meet recording needs with an eye toward efficiency, simplicity, and the context of their delivery media.
Acoustical design of an evolving post production facility at a creative arts college
Authors: Paek Hyun , Siebein Gary W. , Vetterick Matthew , Miller Jennifer , Roa Marylin
Published: November 2021

A private college began to consider building a screening room and production studio in 2010. The original site was in an existing multi-media exhibit building with the studio located under the main computer server for the campus and next to a mechanical room. After bringing this project very close to fruition, the program projections had already outgrown the project. The college decided to expand the program and build a combined post production and recording facility with three sound stages on an empty piece of land on the edge of the campus. The design evolved in conjunction with the sound designer from New York, production consultant from LA, the architect, the acoustical consultant, the college, a contractor and the rest of the design team. Once the design was nearing completion and the building was being constructed, many changes were initiated by the users to reflect their current ideas. Computer models of the spaces were constructed and the acoustical designs tested for each of the evolving solutions. The evolution of the project continued as equipment was being selected for the room. When the project was almost completed a Dolby Atmos system was purchased for the main screening room so that even after construction was almost complete, additional design changes had to be made and evaluated. Post construction acoustical testing and the critiques of the users have all been exceptionally positive given the long and winding road that the project took to completion.
Design of spaces for recording and live broadcast within existing physical design limitations
Authors: Hougland Dana S. , Healey Robert
Published: November 2021

It is optimum to start the design of studios for live broadcast and recording using ideal proportions. At times existing building conditions limit the design height or configurations that are possible. This paper examines the design of three studios for live broadcast that are confined either by height, size, location, or a previous design. The three studios serve as live broadcast spaces for classical music, contemporary music, interviews, and jazz. Two of the studios include options which integrate live audiences. Design solutions are presented as well as measured performance results. Results will include before and after testing where existing studio acoustic conditions were modified.
Soundscape metrics: What are we measuring?
Authors: Stocker Michael
Published: November 2021

The coinage of the term “Soundscape” can trace its origin back to composer R. Murray Schafer’s soundscape studies in the 1960s, along with his seminal book “Soundscape: The Tuning of the World,” which framed the term in the phenomenological context of how we inhabit our acoustical environments. The term remained largely a philosophical conceit based on subjective impressions of inhabited sound environments until it was reined in by way of ISO 12913.1:2014 (Definition and conceptual framework), and ISO 12913.2:2014 (Data collection and reporting requirements). In these standards the conceptual framework includes (1) context, (2) sound sources, (3) acoustic environment, (4) auditory sensation, (5) interpretation of auditory sensation, (6) responses, and (7) outcomes. With the exception of (4) auditory sensation, and (5) interpretation of auditory sensation, these characteristics could all be used in non-human bioacoustic assessments and standards—utilizing the same indicators (measured by instruments). Where our toolbox falls short is in the “descriptors” because we have not yet found much success translating animal interpretations of their experience of their sound environments. In order to derive some predictable metrics of these, we would need to develop reliable ways of interpreting responses and outcomes correlated to context, sound sources, and acoustic environments.
Global and regional soundscape modeling for ships and wind
Authors: Heaney Kevin D. , Verlinden Christopher , Murray James , Heaney Andrew , Munoz Tessa
Published: November 2021

There has been a growing understanding of the importance of the ocean soundscape on marine ecosystem health. With sound traveling to great distances in the open ocean, particularly at lower frequencies (below 200 Hz) ships that are a great distance away can impact the local sound levels. There is a need to be able to understand the relative portion of the measured sound levels which can be attributed to anthropogenic sources (ships, seismic survey vessels, navy sources, pile driving) and to natural sound sources (wind and waves, marine mammals, earthquakes, ice). Modeling approaches provide the opportunity to evaluate the excess noise for a given region (anthropogenic sound levels above the natural or ambient levels). A set of results are presented where the shipping and wind levels are computed for a single measurement position, a regional scale (Atlantic Outer Continental Shelf, the Arctic) and for the entire world’s oceans. Modeling results for the increase in shipping noise levels in the Arctic Ocean due to reduced ice extent and a longer summer transit season are presented, as well as for the reduction on global sound levels due to the initial onset of COVID-19.
Using principal component analysis for marine soundscape research: A case study from Taiwan
Authors: Guan Shane , Lin Tzu-Hao
Published: November 2021

Recent years have seen enormous increases in research on marine soundscape, as underwater acoustic sensors are becoming more affordable, coupled with a growing interest and increased concerns on underwater noise impacts on marine fauna. However, when faced with large amounts of data, there are significant challenges regarding how to analyze large datasets effectively and accurately to make informed decisions. In this study, we used principal component analysis (PCA) to analyze the temporal, spatial, and spectral patterns of the soundscape from major contributing sources in a shallow water coastal environment at two locations in Taiwan in early and late summer of 2012. Acoustic intensity levels were analyzed in three frequency bands: 150–300 Hz, 1.2–2.4 kHz, and 3–6 kHz. The PCA results show higher acoustic intensity in the 1.2–2.4 kHz band at night than during daytime hours, and relatively high acoustic intensity levels overall in the 150–300 Hz frequency at all times. In addition, a large temporal relationship was observed between early and late summer in the 1.2–2.4 kHz band. The results show that PCA has the potential to provide a simple but reliable way to quantify the dynamics of marine soundscapes.
Real-time detection and classification of underwater soundscape signals via a convolutional autoencoder
Authors: Veirs Val , Veirs Scott
Published: November 2021

Underwater sounds come with a wide range of frequency components and with a wide range of time intervals. For example, individual killer whale (Orcinus orca) calls are typically one or two seconds long. Humpback whale (Megaptera novaeangliae) calls range from second long moans to half-hour songs. Speed boats can pass a hydrophone in seconds to minutes. Large ships create signals above background for many minutes. Here fixed 100x100 dimension spectrograms having exponentially increasing time windows of 3, 15, 75, 375, 1875, 9375 seconds are calculated and classified in real time via an autoencoder used as an acoustic pattern detector followed by a supervised convolutional neural network with softmax output. The autoencoder was trained on underwater sound (∼1 Tb) at Orcasound Lab, San Juan Island, WA. The system is designed to classify incoming real-time signals to one or more of twelve different classes (background, killer whale, Southern Resident, Biggs killer whale, humpback whale, breaking waves, kayak paddles, speedboat, displacement boat, large ship, large ship with shaft rub, large ship with repeating sound pattern). The design and efficacy of this detection/classification system will be reported.
Data-driven approaches for ray-based ocean acoustic tomography
Authors: Saha Priyabrata , Durofchalk Nicholas C. , Jin Jihui , Romberg Justin , Mukhopadhyay Saibal , Sabra Karim G.
Published: November 2021

Ray-based acoustical tomography typically provides estimates of local ocean sound speed fluctuations from precise measurements of acoustic travel times fluctuations (with respect to a reference environment) between multiple sources and receiver arrays along with a model of the ray propagation in the reference (i.e., fluctuation-free) environment. Traditionally, this is achieved using a sensitivity kernel, a Born–Frechet linearization of the non-linear relationship between ray arrival-times and sound speeds fluctuations. However, computing the full sensitivity kernel can be computationally intensive and is restricted to only small sound-speed fluctuations (due to the linearization procedure) and does not inherently leverage any available history of the arrival time or sound speed fluctuations which may have been collected prior to performing the inversion procedure. As an alternative solution for ray-based acoustical tomography, we investigated the use of data-driven methods, such as linear regression, nearest neighbors, neural networks, and kernel (ridge) regression, to directly learn the non-linear relationship between sound speed fluctuations and ray arrival time variations using previously collected measurements. Additionally, the experimental training data set is augmented by generating synthetic SSPs based on empirical orthogonal function analysis of the historical SSP data. This approach is demonstrated for short vertical bottom-mounted arrays deployed in littoral environments.
Trans-dimensional inversion for sediment attenuation using modal dispersion data collected by an underwater glider
Authors: Jiang Yong-Min , Dosso Stan , Bonnel Julien , Wilson Preston S.
Published: November 2021

This paper inverts modal-dispersion data collected by an underwater glider to estimate a layered seabed geoacoustic model including sediment attenuation as well as sound speed and density. The data considered here were collected during the 2017 Seabed Characterization Experiment (SBCEX17) conducted on the New England Mud Patch. The distance between the (combustive) sound source and the hydrophone-equipped (Teledyne Webb Research Slocum) glider was approximately 8 km. The frequency range considered was from 20 to 392 Hz, and 6 modes were resolved from the data using warping. Previous work has demonstrated that the positions of dispersive acoustic modes in the time-frequency plane provide information to estimate seabed sound-speed and density profiles. Including the relative energy distribution in the time-frequency plane (normalized modal amplitudes and/or amplitude ratios between modes) provides additional information to also estimate sediment attenuation, which is carried out here using a trans-dimensional Bayesian inversion. In addition, uncertainties of the seabed sound speed and density with/without modal energy information are compared. [Work supported by ONR.]
Estimating ocean variables using ambient noise interferometry
Authors: Ragland John , Abadi Shima
Published: November 2021

Ambient noise interferometry is a method of estimating the time domain Greene's function (TDGF) by correlating and averaging sound from adjacent hydrophones. These averaged cross correlations are called noise cross correlation functions (NCCFs). Noise interferometry has been used in ocean acoustics to estimate ocean variables such as water temperature by measuring propagation times. In this talk, a 6-year NCCF stack between two Ocean Observatories Initiative cabled array hydrophones is investigated. The hydrophones are separated by 3.2 km, and are bottom mounted at a depth of 1500 meters. They are located in the caldera of the Axial Seamount volcano approximately 470 km off the Oregon coast. The TDGF estimate from the NCCF stack contains clear, multipath arrivals. Fluctuations in the arrival time over the six years are on the order of a single time bin. However, if the signal to noise ratio is high enough, it is possible to measure the arrival times with more accuracy than a single time bin. In this presentation, signal processing methods to accurately estimate the propagation time will be explored, as well as the viability of inverting these multipath arrival times to estimate ocean variables such as water temperature. [Work supported by ONR.]
Ranging to fin whale calls at full ocean depths using single ocean bottom seismometers
Authors: Hilmo Rose , Wilcock William S.
Published: November 2021

Fin whale calls are routinely recorded on ocean bottom seismometers (OBSs), but the networks are often too sparse for multi-station call localization. Single station ranging methods are thus important for efforts to utilize OBSs for population density studies. Ranging using the timing and amplitude of multipaths has been demonstrated in relatively shallow (∼2500 m) settings, but in sedimented regions it is challenging to detect the first multipath at small ranges because seafloor reflections have low amplitudes at high incidence angles and subseafloor reflections often have higher amplitudes. To enhance the identification of weak multipaths, we consider all calls in 10-min time windows together. Calls are detected using spectrogram cross-correlation to yield a time-dependent recognition score. The time difference between direct and first multipath arrivals is identified by (1) autocorrelation of the recognition score and (2) spectrogram cross-correlation of the sum of spectrograms for all detected calls. The range is estimated by comparing this time with the predictions of ray tracing. We have tested these methods at five deep (4200–6000 m) OBS sites with contrasting seafloor properties. The results are promising but show the importance of understanding the nature of subsurface reflections.
Suppressing tissue clutter in the presence of motion and nonlinear propagation of ultrasound
Authors: Wahyulaksana Geraldi , Wei Luxi , Schoormans Jasper , van der Steen Antonius F. , Vos Hendrik
Published: November 2021

Visualizing blood flow in small vessel with ultrasound imaging is a useful diagnosis tool for evaluating organ condition. The usage of encapsulated microbubbles that have non-linear response as contrast agents, in combination with pulsing schemes that suppress the linear tissue signal can improve the sensitivity and specificity of ultrasound flow imaging. However, the nonlinear propagation when ultrasound travels through tissue and microbubble clouds reduce contrast detection. Moreover, tissue motion causes clutter artifacts and imprecise combination of the multi-pulse transmission scheme, impairing image quality. We have previously developed an independent component analysis (ICA)-based clutter filter for high framerate imaging, which performed better than the widely used singular value decomposition (SVD) filter in presence of fast tissue motion. In this study, we examined the performance of ICA filter in combination with power modulation (PM) pulsing schemes to detect flow signal. We performed an in vitro- measurement that emulated ultrasound propagation through cloud of microbubbles and fast tissue motion. The results showed that the combination of PM and ICA filter achieved up to 6dB contrast-to-background ratio improvement compared to only PM. This improvement could be significant for myocardial perfusion imaging, where rapid tissue motion and nonlinear propagation through clouds of microbubbles are expected.
Aberration-inducing body wall phantom for high-intensity focused ultrasound applications
Authors: Peek Alex T. , Thomas Gilles P. , Khokhlova Tatiana D. , Rosnitskiy Pavel , Yuldashev Petr V. , Leotta Daniel , Khokhlova Vera A.
Published: November 2021

Aberrations induced by soft tissue inhomogeneities distort acoustic fields and often complicate HIFU therapies. An aberration-generating phantom was designed and fabricated to mimic the acoustic effects of a porcine body wall. A rippled surface pattern replicating inhomogeneities of size scales relevant to the porcine body wall was transferred to a large phantom made of fat-like and muscle-like gel materials. The acoustic distortions produced by the phantom and an ex vivo porcine body wall were characterized by hydrophone measurements with a 256-element 1.5 MHz focused ultrasound array (diameter = 144 mm, F# = 0.83). Insertion of the phantom generated large distortions for both linear and nonlinear beam focusing including displacement of the focus (up to 0.3 mm transversely), enlargement of the focal region, and reduction in focal pressures due to aberration (up to 2.5-fold peak positive pressure reduction). The phantom and porcine body wall produced similar levels of aberration and attenuation effects. An aberration correction approach was leveraged to isolate the quantitative effect of aberration and to restore shocks in nonlinear waveforms in the focus. Boiling histotripsy treatments through the phantom or body wall were subsequently demonstrated in a hematoma sample. [This work was supported by NIH R01EB7643 and R01EB25187, and RSF 20-12-00145.]
A focused limited-diffraction beam for high-resolution imaging
Authors: Lu Jian-yu
Published: November 2021

Unfocused limited-diffraction beams such as Bessel beams and X waves have been studied extensively to obtain a large depth of field for medical imaging. In this study, a focused zeroth-order Bessel beam j0(αr), where α = 1202.45 m−1 and r is the radius, produced with a 50 mm diameter and 2.5-MHz transducer and with an acoustic lens of 50-mm focal length (f-number = 1) was used to obtain a C-mode image of an object in water (0.6mm wavelength). The results of the study showed that at the focal distance, the lateral resolution of the image obtained with an unapodized transducer in both transmission and reception was lower than that obtained with an unapodized beam in transmit but the j0 Bessel beam was used in receive. Beam plots of the unapodized beam and the j0 Bessel beam at the focal distance showed that the lateral beamwidths were about 0.78 and 0.59 mm, respectively. The 0.59-mm beamwidth of the focused Bessel beam is better than that of the diffraction limit (1.22 × wavelength × f-number = 0.732 mm). The decreased beamwidth of the j0 Bessel beam results in a higher lateral image resolution while the sidelobes of the beam were suppressed by the focused unapodized transmit beam.
Color Doppler imaging of pure crystals in hyperbaric conditions
Authors: Rokni Eric , Simon Julianna C.
Published: November 2021

The color Doppler ultrasound twinkling artifact is a rapid color shift that appears on some kidney stones and other pathological mineralizations during ultrasound imaging. Twinkling on kidney stones is primarily attributed to scattering from stabilized microbubbles as increasing hydrostatic pressures has been shown to decrease twinkling. However, it is unknown whether microbubbles are also present and cause twinkling on other forms of pathological mineralizations or pure crystals. In this study, 5 cholesterol and 5 calcium phosphate crystals were grown in vitro from supersaturated solutions and imaged in a custom-built, hydrostatic pressure chamber with a Philips/ATL L7-4 transducer and Vantage-128 research ultrasound system. Hydrostatic pressure was increased to a maximum of 14 MPa while saving IQ data at 1 fps for evaluation of Doppler power. On all 10 imaged crystals, twinkling was found to decrease by approximately 90% when pressures reached 4 MPa absolute. Twinkling reappeared when the pressure was returned to atmospheric levels. These results suggest that bubbles are present on pure crystals and give rise to the twinkling artifact. [Work supported by NSF CAREER 1943937 and NSF GRFP DGE1255832.]
Haze Artifact reduction in cardiovascular synthetic aperture imaging in use of intertransmission coherence factor
Authors: Ikeda Teiichiro , Ishihara Chizue , Hiroshima Misaki , Hisatsu Masnori , Kuribara Hiroshi
Published: November 2021

In cardiovascular medical ultrasound applications, the use of spatially decimated focused-transmission synthetic aperture (SA) imaging is promising to achieve both high SNR and high-frame-rate. But unlike prevailing planar/divergence SA, the use of focused transmission where the virtual source of SA is placed in the imaging area for the better penetration with up to 160-mm field-of-view result in severe haze artifacts in the heart chambers. We hypothesize the haze is caused by the grating lobe due to the decimated focused transmission of SA and propose a method for reducing artifacts by using the intertransmission coherence factor (ITCF) [1] focusing on the fact that SA grating lobe signal is less coherent than the main lobe signals. Simulation and in vivo experiment revealed that there is a strong relation between the grating lobe and haze artifact. When imaging a human heart (under approval of institutional review board) using 4-times transmission decimation (equivalent to 160 frames/s) with a phased array probe, the ITCF method was able to reduce the grating artifacts within heart chambers greatly by more than 15 dB, while maintaining the intensity of myocardium, LV/LA wall, mitral valve, and other tissue/organ structures. [1] Ikeda et al. IEEE Trans. UFFC, doi: 10.1109/TUFFC.2021.3088678 (2021).
Uncertainty quantification of quadratically nonlinear local damage size quantification using nonlinear ultrasonics
Authors: Ghodake Pravinkumar R.
Published: November 2021

Backscattered and forward scattered harmonic waves from local damage modeled as quadratically nonlinear material in a 1D bar are used to solve a deterministic inverse problem to find the local damage size by Ghodake (2020). Due to highly nonlinear (|sin(x)/x|) nature of the proposed forward problem, the constrained nonlinear deterministic optimization problem was solved using non-gradient-based algorithms. The forward model is a function of input frequencies, linear wave velocity, and local damage size. In practice, slight uncertainty of these parameters gives a completely different solution. To address this problem, uncertainty quantification of the modified forward problem is carried out along with solving the inverse problem using reliability-based design optimization (RBDO) and Bayesian Inverse (BI) approaches. In RBDO studies, Quantile Monte Carlo (QMC) approach gives more reliable and accurate results in comparison with approaches such as reliability index approach (RIA), performance measure approach (PMA), sequential optimization and reliability assessment (SORA), and inverse first-order reliability method (FORM) integrated with optimization methods such as interior-point (IP) and sequential programming (SQP). Multiple models are solved using the BI approach. Support vector machines regression (SVR), polynomial chaos expansions (PCE), and Kriging surrogate models are used along with RBDO and BI to reduce computational time.
Finite impedance boundary conditions determined in situ for modeling underwater acoustical measurement in laboratory tanks
Authors: Vongsawad Cameron T. , Neilsen Tracianne B.
Published: November 2021

In underwater acoustics, laboratory tank sound propagation models may be improved using in situ characterization of water tank boundaries. An underwater acoustic tank model is developed with finite impedance boundaries determined in situ from impulse response measurements calculated from the frequency deconvolution of swept-sine signals following techniques commonly used in room acoustics. Impulse responses were used to obtain the acoustic absorption of the acrylic tank walls through reverse Schroeder integration determining the reverberation time and solving the Eyring equation for absorptive effects. This approach improves modeling of sound propagation in water tanks and is validated with numerical test cases and measurements. An improved tank model considering measured finite impedance boundaries will further develop the ability for more realistic data simulation in water tanks which will be used to design machine learning refinement.