bluuebunny/crossref_metadata_2025 huggingface dataset:
An overview of ambient sound using OOI hydrophone network
Authors: Ragland John , Schwock Felix , Munson Matthew , Abadi Shima
Published: November 2021

The NSF-funded Ocean Observatories Initiative (OOI) is a large-scale project that provides a unique observation of the ocean, collecting acoustic, meteorological, and oceanic datasets. Specifically, for hydrophone data, there are five low frequency hydrophones (Fs = 200 Hz), and six broadband hydrophones (Fs = 64 kHz) dispersed around the north-east pacific. This acoustic dataset presents numerous potential areas of study in the field of ambient sound analysis. In this talk, we analysis 6 years of acoustic data to identify prominent features that are present in the OOI acoustic dataset. Some notable occurrences that are observed in the dataset include volcanic activity, rain and wind noise, fin whale vocalizations, and shipping events. For all low frequency hydrophones and four of the six broadband hydrophones, we will present long-term spectrograms, time-series trends for different spectral bands, different acoustic features that are present in the dataset, and different statistical metrics about the acoustic environment. We find that 6-year, acoustic, trends vary depending on the location of the hydrophone and the spectral band that is observed. Some locations and spectral bands see increases in spectral levels while others see decreases in spectral levels over the course of the 6 years. [Work supported by ONR.]
Gas-stabilizing solid cavitation nuclei for systemic or transdermal ultrasound-enhanced drug and vaccine delivery and immunomodulation
Authors: Lyons Brian , Hettinga Johanna , Balkaran Joel , Collins Abigail , Maardalen Matilde , Katti Prateek , Mannaris Christophoros , Bau Luca , Smith Cameron , Gray Michael , Kwan James , Carlisle Robert , Coussios Constantin
Published: November 2021

Originally developed for diagnostic purposes and already approved for clinical use, lipid and protein-shelled microbubbles were a natural choice as initial nucleation agents for cavitation-based therapies entering the clinic. However, several emerging therapeutic ultrasound applications require nuclei that: (i) are significantly smaller in size, in order to overcome a particular biological barrier such as the leaky vasculature of tumours or the stratum corneum; (ii) offer greatly increased cavitation persistence, both during a single extended ultrasound pulse and in terms of extended circulation following intravenous administration; (iii) have better resilience to sudden ambient pressure changes in order to enable direct injection without nuclei destruction into tissue targets via a needle and syringe; and (iv) are made of materials or have an increased payload or surface area that can interact beneficially with the relevant tissue target during or following cavitation. Gas-stabilizing solid particles will be reviewed in this context, providing an overview of their known characteristics in terms of size distribution, associated acoustic emissions, cavitation thresholds, cavitation persistence and circulation. The relationship between this acoustic characterization and associated bioeffects including drug and vaccine delivery, and immunomodulation will subsequently be explored.
Sonobiopsy increases release of circulating tumor DNA for sensitive molecular diagnosis of glioblastoma
Authors: Pacia Christopher P. , Yuan Jinyun , Yue Yimei , Xu Lu , Nazeri Arash , Desai Rupen , Gach H. M. , Wang Xiaowei , Talcott Michael , Chaudhuri Aadel , Dunn Gavin , Leuthardt Eric , Chen Hong
Published: November 2021

Though surgical biopsies provide direct access to tissue for genomic characterization, they are invasive and pose significant clinical risks. Brain cancer management via blood-based liquid biopsies is a noninvasive alternative; however, the blood-brain barrier (BBB) restricts the quantities of circulating brain tumor-derived molecular biomarkers necessary for sensitive diagnosis. Focused ultrasound-enabled blood-based liquid biopsy (sonobiopsy) locally disrupts the BBB to release circulating tumor DNA (ctDNA). Magnetic resonance imaging was performed to guide FUS sonication and evaluate the extent of BBB disruption. Droplet digital PCR was used to quantify the levels of circulating tumor DNA. Histological staining and flow cytometry were used to assess off-target tissue damage and release of tumor cells, respectively. Compared to conventional blood-based liquid biopsies, sonobiopsy enriched the ctDNA and improved the detection sensitivity of EGFRvIII from 7.14% to 64.71% and TERT C228T from 14.29% to 45.83% in the mouse glioblastoma model. We developed a porcine GBM model to characterize the translational implications of sonobiopsy and demonstrated that sonobiopsy improved the sensitivity from 28.57% to 100% for EGFRvIII and from 42.86% to 71.43% for TERT C228T. Converging evidence from both glioblastoma models strongly supports the clinical translation of sonobiopsy for noninvasive, sensitive molecular characterization of brain cancer.
Predicting spontaneous preterm birth risk is improved when quantitative ultrasound data are included with prior clinical data
Authors: McFarlin Barbara L. , Roshan Shashi , Han Aiguo , Simpson Douglas G. , O'Brien William D.
Published: November 2021

Predicting women at risk for spontaneous preterm birth (sPTB) has been medically challenging due to lack of signs and symptoms of preterm labor until intervention is too late. Hypothesis: advanced statistical modeling predicts sPTB risk from quantitative ultrasound (QUS) plus prior data (prior birth history through first clinical cervical length) better than that of prior data alone. Study population included 250 full-term births (FTBs) and 25sPTBs. QUS scans (Siemens S2000 & MC9-4) were performed using a standard cervical length approach by registered diagnostic medical sonographers. Two cervical QUS scans were conducted at 20 ± 2 and 24 ± 2 wk gestation. Multiple QUS features were processed from calibrated raw radiofrequency backscattered ultrasonic signals. Two statistical models designed to determine sPTB risk were compared: (1) QUS plus prior data and (2) prior data alone. Test ROC AUC compared both models. Using statistical methods, QUS plus prior data identified women at risk for sPTB with better AUC (0.68; std error 0.01; 95% CI, 0.66–0.70) than that of prior data alone (0.63; std error 0.01; 95% CI, 0.61–0.65). Even with only 25 sPTBs, data suggest that there is value added for predicting sPTB when QUS data are included with prior data. [R01HD089935.]
A step by step educational guide to designing and testing an underwater acoustic modem
Authors: Rashid Rami , DellaMorte John , DellaMorte James , Zhang Erjian , Abdi Ali
Published: November 2021

We examine the design and systematic implementation of a receiver system for underwater acoustic communication. The system includes, but is not limited to, passband filter, down converter, matched filter, and detection logic. Our final implementation target is a frame-based system to minimize memory use and system latency. The matched filter uses the overlap-save method in frequency domain to reduce computational cost. Initially, the system is designed and tested for performance using the MATLAB platform in a non-real time vector-based implementation. The code is then restructured to a MATLAB frame-based model. The code contains several functions; each function performs a specific task and maintains its own histories as needed. Once the performance of the frame-based model is measured to be identical to the vector-based model, we systematically move each function to C + +. Each C + + function is individually substituted into the frame-based model using MEX files and verified for performance. Once all C + + functions are verified for performance, the entire C + + implementation is uploaded to the Popoto Modem™ real-time hardware and performs real-time transmission and reception in both air and underwater environments, with known and tested performance characteristics. [Work supported in part by NSF, Grant IIP-1500123, the INTERN program.]
Design of virtual reality for teaching ultrasound in medical and engineering education
Authors: Lee Jan , Coiado Olivia
Published: November 2021

This works presents the design of a virtual reality (VR) platform that generates 3D models from ultrasound imaging used to teach medical and engineering students about anatomical structures. The VR platform will allow students to learn about the theory of wave propagation in tissues by providing 3D visualizations of abstract physics concepts and organ systems in an immersive and engaging environment. This phase of the project has been focused on learning to develop VR environments and how to translate medical imaging formats into a feasible tool. The specific focus has been on converting DICOM (Digital Imaging and Communications in Medicine) files into elements that can be managed in the VR environment (Unity 3D Development). This includes converting imaging data sets into 3D meshes that can be displayed and manipulated. The nearly infinite control over virtual environments can present alternative visualizations of ultrasound that may be accessible to the learner. The use of acquired ultrasound data within the virtual space will help learners transfer skills into point-of-care ultrasound (POCUS). The VR environment will help students to explore ultrasound without the limitations of a real patient and guide them to the physics principles to better understand ultrasound propagation in the human body.
Teaching speech acoustics concepts in an undergraduate speech science course: Are distributed or massed practice lab assignments more effective?
Authors: Siren Kathleen
Published: November 2021

Educational research holds that individuals learn concepts more effectively when practice applying these concepts is distributed rather than massed. However, few studies have investigated distributed versus massed practice for student learning of a set of related concepts. This study investigated student learning and retention of speech acoustics concepts in an undergraduate speech science course. In one class design, students completed several short speech acoustics labs spaced throughout the semester to practice applying learned concepts as the semester progressed. In another class design, students completed one extensive speech acoustics lab at the end of the semester to apply concepts learned throughout the semester. Students in all courses completed a comprehensive examination at the end of the semester. An analysis of summative assessment data indicates that distributed practice may be more effective in facilitating student learning and recall of individual concepts. However, massed practice may promote broader conceptual learning of related concepts, possibly by facilitating discovery of connections across concepts.
Imaging solids using full waveform inversion
Authors: Kucukcoban Sezgin , Goh Heedong , Kallivokas Loukas
Published: November 2021

Wave-driven approaches have long been dominant in the nondestructive evaluation of both engineered and natural systems. In this presentation, we discuss recent progress in the full-waveform inversion (FWI) approach for the material characterization and condition assessment of solids probed by elastic waves. In FWI, characterization and localization of defects is automatically revealed once the distribution of the spatially-varying material properties is completed. In this work, we seek to image the Lamé parameters of arbitrarily heterogeneous solids, when probed by elastic waves in the time domain. Accordingly, we use the apparatus of PDE-constrained optimization and seek the Lamé parameter distributions that minimize the misfit between measured and computed responses, subject to the governing PDEs. As is commonly the case, the resulting inverted profiles of the second Lamé parameter (μ) are of better quality than those of the first (λ). To improve the resolution of both Lamé parameters, we discuss the use of three robustifying schemes, namely, source-frequency continuation, regularization factor continuation, and a search direction-biasing scheme. We demonstrate with numerical experiments the effect the schemes have on the inversion process and conclude with an application of the robustified full-waveform method to a challenging adaptation of the benchmark Marmousi2 model.
Sound and vibration measurements for pipe wall condition assessment of concrete pressure pipes
Authors: Richarz Werner , Richarz Harrison F. , Sun John , Karimi Fatemeh , Ricketts Taiwo
Published: November 2021

The condition of buried watermains and similar pipelines can be assessed by non-intrusive means. To this end certain features of sound propagation in the water column within the main are measured. Most applications use the Korteweg-Lamb correction to estimate the average wall thickness for homogeneous pipes. For complex composite structures such as concrete pressure pipes, condition assessment is presently based on a great deal of empiricism. This can now be replaced with proper physical models based on measurements conducted on a 25 m long test pipe. Using controlled sound sources, hydrophones and surface mounted accelerometers, features of the acoustic waves inside the water column and the associated wall vibrations were deduced from two-point space-time correlations. The data permits the determination of the complex-valued wavenumbers as well as the dynamic coupling of the liquid column and the pipe wall from which certain properties of the pipe wall can be characterized to ascertain if the pipe is fit for purpose.
Stop voicing contrast in Lio
Authors: Miatto Veronica , Wivell Grace B.
Published: November 2021

Typologically, two-way or three-way voicing contrasts in stops can be reliably defined along the VOT continuum, that is, by measuring the gap between the start of voicing and the stop burst, which can be negative or positive. In the literature, three main categories are therefore derived: prevoiced, unaspirated, and aspirated stops (Keating, 1984; Lisker and Abramson, 1964; and Cho et al., 2019). For Lio, an understudied Austronesian language of Central Flores (Eastern Indonesia), it has been claimed that the stop voicing contrast is realized with prevoicing for voiced stops and aspiration for voiceless stops (Elias, 2018). However, it is unclear how long the aspiration is, and whether Lio voiceless stops can be characterized as unaspirated or aspirated; furthermore, this claim was not based on an acoustic analysis, and relied heavily on one speaker. This study offers a descriptive analysis on voicing contrasts in Lio stops. The acoustic analysis reveals that the contrast is one of ‘true voicing’, with the closure phase of voiced stops presenting voicing (prevoiced) and short-lag VOT voiceless stops (unaspirated). This study will offer a valuable contribution to voicing contrasts typology, especially compared to Cho et al. (2019), and serves as a building block for future Lio research.
Acoustic features of palatalized consonants in Nasa Yuwe
Authors: Vanzeveren Elodie , Diaz Esteban , Rojas Tulio , Demolin Didier
Published: November 2021

Nasa Yuwe a Colombian language spoken in the Cauca presents complex features of palatalization [1,2]. Stops and affricates can be palatalized, aspirated and palatalized-aspirated at all places of articulation while prenasalized consonants and fricatives can only be palatalized. Data for this study were recorded from an acoustic recording session and by combining, in a second phase, synchronized acoustic, EGG and oral airflow recordings from 6 speakers (3 female and 3 male). Results show that all palatalized stops are characterized by a short frication noise at the end and a F3/F4 pole at the start of the following vowel. Aspirated stops have a greater frication noise duration and an open glottis. Palatalized-aspirated stops and affricates are produced with frication noise, a F3/F4 pole at the start of the following vowel and an open glottis. Palatalized-aspirated consonants have two phases: a short and intense frication noise accounting for the palatalization, followed by a lower intensity aspiration noise. Both phases can be distinguished by their FFT spectra and oral airflow volume velocity. Prenasalized consonants behave as palatalized stops but without the aspiration feature. Palatalized fricatives have a resonance during the frication, reflecting a tongue movement towards the palatal place. [1] E. Dias, El Habla Nasa (paez) de Munchique: Nuevos Acercamientos a Su Sociolingüistica, Fonologia y Morfosintaxis (Université Lumière Lyon 2, 2019). [2] T. Rojas, La Lengua Paez (Ministerio de Cultura, Bogota, 1998).
Nomlaki vowel quality: An acoustical and archival examination
Authors: Björklund Anna
Published: November 2021

This study examines vowel quality and duration in Nomlaki, a Wintuan language of Northern California that survives via archival recordings. Phonemic vowel length is reconstructed in Proto-Wintuan (Shepherd, 2005) and is inherited in Nomlaki’s sister languages (Pitkin, 1984; Lawyer, 2015), producing a vowel system of five long/short pairs. Despite this, current orthography used in Nomlaki tribal language revitalization distinguishes Nomlaki vowel pairs via tense/lax quality. This study uses data from archival recordings to document how F2 primarily distinguishes these historically long/short vowel pairs. Data consisted of 1574 tokens spoken by two male speakers recorded in 1953 and 1975. Each token contained F1, F2, F3, and duration information; 234 tokens were labelled according to the official tribal spelling when spelling was known. A Linear Discriminant Analysis (LDA) model was fit with 5-fold cross-validation on the labelled set, after which each of the other tokens was assigned a vowel label per the LDA model. The model was 64% accurate. 86.7% of the variance was accounted for by the first dimension, 8.2% by the second, and 4.8% by the third. These dimensions were primarily weighted by F2, F1, and duration, respectively. The author has no known conflicts of interest.
Plumb-full of hush to the Brim: Park sound levels per American National Standards Institute S12.100-2014
Authors: Betchkal Davyd H.
Published: November 2021

In this talk we explore the use of ANSI/ASA S12.100-2014, the contemporary standard to ‘define and measure the residual sound in protected natural and quiet residential areas’. Key provisions are digested using examples from measurement sites within The National Park System. Special attention will be paid to the acoustic form of natural areas in contrast to urban areas (Secs. 3.12 and 3.13), avoiding bias from transients (Secs. 5.2 and 5.3), and acknowledging measurements censored by instrument background noise (Secs. 5.9 and 6.4). Adoption of standard practice in these few areas could vastly improve the accuracy of impact assessments for public lands nationwide.
Improving fan inlet conditions to reduce noise
Authors: Hoover K. Anthony , L'Italien Zachery O.
Published: November 2021

This presentation will review various examples of fan inlet conditions that caused excessive noise in different frequency ranges, and system modifications for noise reduction that involved a few intermediate steps to maximize effectiveness and sometimes to reduce initial client resistance. Examples will include several large air handlers, a healthcare facility exhaust fan, and some informal experiments.
Expectation of self-generated sounds drives predictive processing in mouse auditory cortex
Authors: Schneider David , Audette Nicholas , Zhou WenXi
Published: November 2021

Behavior exerts a strong influence over sensory responses in the brain. In the auditory cortex, neural responses to self-generated sounds are suppressed, suggesting that prediction may play a critical role in local sensory processing. However, it is unclear whether this phenomenon derives from a precise movement-based prediction or how it affects the neural representation of incoming stimuli. We address these questions by designing a behavioral paradigm where mice learn to expect the predictable acoustic consequences of a simple forelimb movement. Dense neuronal recordings from auditory cortex revealed suppression of neural responses that was strongest for the expected tone during a narrow time window surrounding the specific sound-associated movement. Predictive suppression was concentrated in layers 2/3 and 5, preceded by the arrival of movement information in deep layers, and driven by motor-sensory coupling rather than task engagement, behavioral relevance, or reward association. Despite large-scale suppression at the population level, the auditory cortex retained a sparse representation of the expected self-generated sounds, while a substantial population of auditory cortex neurons in L2/3 and L5 encoded prediction errors. These findings illustrate that expectation, learned through motor-sensory experience, drives layer-specific predictive processing in the mouse auditory cortex.
Willis coupling in micromorphic elasticity
Authors: Wallen Samuel P. , Goldsberry Benjamin M. , Haberman Michael R.
Published: November 2021

Acoustic and elastic metamaterials (AEMM) are artificial materials whose performance is engineered to exceed naturally occurring materials and conventional composites, often leveraging complex microstructural geometry and strong dispersion. Generalized continuum (GC) theories, such as micromorphic elasticity, are extensions of classical elasticity that capture the effects of microstructure via inclusion of internal kinematic variables and/or higher-order gradients of displacement, and have received renewed interest as potential reduced-order models for AEMM. An alternative AEMM modeling framework is the elastodynamic homogenization theory of Willis, which yields an effective medium whose constitutive relations contain stress-acceleration and momentum-strain-rate couplings. Despite the recent popularity of the GC and Willis methods, a comprehensive description of their relationship remains lacking. In the present work, we derive an explicit connection between the Willis and GC models. Specifically, we augment the variational formulation of Mindlin [Arch. Ration. Mech. Anal., 16, 51–78 (1964)] to account for microscale asymmetry of mass density and demonstrate that the resulting boundary value problem may be expressed in the form of a Willis material. This approach helps to elucidate the physical origins of Willis coupling and may offer insights about how other emergent material properties arise from microstructural constituents. [Work supported by ONR.]
Asymmetric Bragg scattering of water-borne sound by identically oriented asymmetric inclusions
Authors: Lawrence A. J. , Xue Yahui , Zhang Xiang , Wilson Preston S. , Haberman Michael R.
Published: November 2021

We report on the modeling, fabrication, and characterization of an innovative design for a heterogeneous material consisting of spherical scatterers with asymmetric material distribution embedded in a thin viscoelastic layer. The material properties of the scatterers are uniformly oriented with respect to the layer thickness. The inclusions consists of unequal parts iron (Fe) and polyetheylene glycol (PEG) with non-uniform distribution of Fe within each inclusion to leading to coupling between monopole and dipole scattering response from individual Fe-PEG scatterers in the long wavelength limit when embedded in a polydimethylsiloxane (PDMS) matrix. Experiments were conducted from 0.5–1.5 MHz in an ultrasonic tank on two different samples.
A Green’s function approach for nonreciprocal vibrations of finite elastic structures with spatiotemporally modulated material properties
Authors: Goldsberry Benjamin M. , Wallen Samuel P. , Haberman Michael R.
Published: November 2021

The spatiotemporal modulation of material properties in acoustic and elastic metamaterials is one way to realize dynamic nonreciprocity for mechanical wave propagation and vibration of finite systems. A recent study on nonreciprocal vibrations of finite elastic beams has shown that strong nonreciprocal input-output responses resulting from the spatiotemporal modulation only occur for a small subset of modulation parameters, which may complicate the design of nonreciprocal systems [Goldsberry et al., Phys. Rev. B 102 (2020)]. In this work, we derive a Green’s function approach for finite elastic systems with spatiotemporally modulated material properties, which mathematically describes the modulated system response for a given set of boundary conditions. As a case example, we investigate two-dimensional flexural vibrations of a plate whose stiffness is modulated in a traveling wave form. We then investigate the first order corrections to the unmodulated system by utilizing an asymptotic expansion in the small parameter defining the modulation strength. Finally, we find conditions on the material and modulation parameters that yield a large degree of nonreciprocity. The present analysis leads to potential applications in acoustic communications, vibration suppression, and energy harvesting. [Work supported by NSF EFRI.]
Weak-form homogenization of two and three-dimensional systems
Authors: Muhlestein Michael B. , Dunn Kyle
Published: November 2021

A homogenization method based on a weak formulation of the dynamic equation for one-dimensional systems was recently developed and published [Muhlestein, J. Acoust. Soc. Am. 147 (2020)]. An important aspect of that homogenization method requires the weak form be written explicitly in terms of the acoustic pressure and the particle velocity, which are continuous quantities at all points in one-dimensional systems. However, for two and three-dimensional systems only the normal component of the particle velocity need be continuous at interfaces, and simply averaging the mass density (as was suggested by the one-dimensional analysis) leads to an inaccurate prediction of the effective mass density even in the quasi-static limit. In this paper we describe a more accurate homogenization method for higher-dimensional systems. A critical result is that the particle velocity does not necessarily approach a macroscopic limit, even for quasi-static signals, and that material properties should be interpreted as applicable for an ensemble-averaged particle velocity. Analytical estimates for the effective material properties are given for stratified media. A numerical simulation is then presented comparing the behavior of a stratified system with the behavior of a homogenized system.
Weak-form homogenization of one-dimensional systems with hidden degrees of freedom
Authors: Muhlestein Michael B.
Published: November 2021

Acoustic metamaterials are synthetic structures that exhibit specific, often exotic, effective material properties for long-wavelength stimuli. One of the principal methods that exotic material properties, such as zero or negative mass density or bulk modulus, may be obtained is through hidden degrees of freedom. An example of a hidden degree of freedom is a resonator attached in shunt to a duct and modeling the system as just a duct with effective material properties. In this example, the resonator is “hidden” from the model by incorporating its (rather profound) effect on the system into the material properties. This paper demonstrates how hidden degrees of freedom may be incorporated into a recently developed homogenization scheme that utilizes the weak form of the dynamic system [Muhlestein, J. Acoust. Soc. Am. 147 (2020)]. Two specific examples will be considered: the shunt resonator, as described above, and a membrane inside a duct. The results are compared with other standard homogenization methods.
Signal processing for architectural acousticians
Authors: Xiang Ning , O'Keefe John P.
Published: November 2021

Architectural acoustics is characterized by its multidisciplinary nature, the multiple disciplines include physical acoustics, engineering acoustics, noise control, psychoacoustics, and signal processing. In recent decades, signal processing has become an integrated body of fundamental knowledge of architectural acoustics. Furthermore, it has advanced technology in architectural acoustics practice. This talk highlights a number of applications in architectural acoustics in which acoustic signals need to be efficiently manipulated and analyzed. In addition, signal processing tools have drastically advanced measurement techniques in architectural acoustics, advanced spatial and temporal analysis of sound fields in enclosures. Signal processing has entered into a wide range of areas, from room-acoustic energy decay analysis, modal analysis, interaural de-correlation for quantifying auditory spaciousness, array signal processing, three-dimensional rendering techniques for auditory displays, time-frequency analysis of impulse response functions, to optimizations, machine-learning and the concept of Pareto Fronts in architectural acoustics. Architectural Acousticians who are equipped with and understand the basic tools of signal processing are able to contribute to advancing knowledge and perform best practices in the architectural acoustics.
Human and machine learning expertise applied to speech and music signals processing
Authors: Kostek Bozena
Published: November 2021

Machine learning techniques provide extensive advances in automated signal and data processing in many fields. One of the critical areas in acoustic signal processing is extracting relevant information from the speech signal. The speech signal contains phonemic variation, temporal structure, prosody, timbre, and voice quality. It also includes various aspects of the speaker’s profile, such as emotions or sentiments. What is easily discerned and analyzed by a human escapes a machine learning-based approach when dealing with all that complexity at once. One may easily see parallels to musical signal processing as such aspects as temporal structure, timbre, and music quality, etc., are of importance, especially as music also carries an artistic message. An example of such a functional concept of music is when it is associated with the image, as the ultimate goal of a film music composer is to enhance or evoke the audience’s emotions. A question appears whether a machine learning technique may discern emotions associated with a given scene the same way as the human does. This paper focuses on the application of machine learning to speech and music signal analyses. It also emphasizes speech and music signal processing covering recent advances in deep learning.
Machine learning for acoustic source localization in room and ocean acoustics
Authors: Gerstoft Peter , Niu Haiqiang , Bianco Michael J. , Ozanich Emma , Wu Yifan
Published: November 2021

Despite decades of development, acoustic source localization has been challenged by mislocations. Instead, we learn the localizations directly from data using machine learning. After a mapping has been learned we test that the mapping generalizes well on test data. We demonstrate the approach in an ocean waveguide as a classification and a regression neural network, in a room acoustic setting we demonstrate how a neural network can alleviate multipath.
The Hilbert-Huang transform: Improvements and applications in vibro-acoustics
Authors: Furlong Trent
Published: November 2021

The Hilbert-Huang transform (HHT) is a relatively new signal processing technique that offers several advantages over traditional Fourier transform analysis. The HHT empirically decomposes a signal into multiple components called intrinsic mode functions (IMF), then returns the instantaneous frequency and energy for each IMF. Having each IMF’s instantaneous frequency and energy for every data sample offers greater frequency resolution in both 2-D and 3-D spectral analysis—a clear advantage when compared to the Fourier transform’s well-known time-frequency resolution challenge. Because the HHT performs signal decomposition empirically no model or prior knowledge about the system is needed, making the HHT a useful technique for analyzing and giving physical interpretation to nonlinear, non-stationary systems. The Fourier transform, however, inherently only provides physical interpretation to linear, stationary systems; increasing the required expertise for use on nonlinear, non-stationary systems. This presentation will give an overview on the HHT algorithm, common modifications, advantages and disadvantages, how its results compare to the Fourier transform, and examples of successfully using the HHT on vibro-acoustic data for monitoring machine wear.
Similarity matrices applied to differentiate between Lombard and natural speech
Authors: Korvel Grazina , Kakol Krzysztof , Kostek Bozena
Published: November 2021

The study aims to present a method of evaluating speech quality in noise and interference conditions based on similarity matrices. For that purpose, sets of words recorded in the presence of disturbing signals along with their clean counterparts are used. First, it is checked to what extent a correct alignment of signals with and without the Lombard effect is important when self-similarity matrices are utilized in the process of feature discerning. Then, self-similarity matrices based on the acoustic parameters concerning speech prosody and alignment are built. Next, a correlation check is performed for feature redundancy. Based on a reduced set of parameters, 2D maps of acoustic features are created for visualization purposes. This is also performed as the cross-check between different languages with and without Lombard speech. Analyses performed shown that self-similarity matrices may be applied for differentiating speech modified by the Lombard effect and non-Lombard utterances. This research is funded by the European Social Fund under the No 09.3.3-LMT-K-712 “Development of Competences of Scientists, other Researchers and Students through Practical Research Activities” measure.
Towards a field deployable alternative to underwater explosive charges
Authors: McNeese Andrew R. , Bonnel Julien , Wilson Preston S.
Published: November 2021

Underwater acoustic experiments and surveys often utilize underwater explosions to produce a high amplitude, broadband event capable of penetrating the seabed and propagating to long range. Although underwater explosive charges have been readily utilized for many decades, an alternative to explosives is of interest due to environmental and logistical concerns. Prior experimentation has demonstrated the viability of the Rupture Induced Underwater Sound Source (RIUSS) that utilizes an expendable diaphragm, known as a rupture disk, as an underwater acoustic source. The device functions by placing a rupture disk over a chamber and mechanically breaking the disk (either by striking on demand or via hydrostatic pressure) at a specified depth to produce high-amplitude, broadband waveforms. Recent experimentation has demonstrated the ability to perform ocean propagation measurements from a small, low cost fishing vessel in the New England Mud Patch by deploying expendable RIUSS units along with small, single channel acoustic moorings. Each of the acoustic moorings and expendable RIUSS units were deployed by hand, allowing the measurements to be gathered with few personnel in a low cost manner. Discussion will focus on recent advancements, fielded deployments, and comparison to related explosive charge propagation measurements. [Work Supported by ONR and ARL:UT IR&D Program.]
Spaced object absorbers, sound absorption coefficients, and the noise reduction coefficient rating in architecture
Authors: Wolfram Eric P.
Published: November 2021

Spaced object arrays (e.g., vertical baffles) are a growing trend for reverberation time reduction in architectural spaces. Unfortunately, the acoustical considerations for these products are significantly more complex than traditional continuous ceiling treatments. Architects and designers are familiar with sound absorption coefficients (Sabins/ft2) and the NRC Rating, but these are technically not applicable to spaced object arrays. Further, product manufacturers consider the correct Sabins/Object over 1/3 octave bands to be too technically complex for marketing purposes. The ASTM E33 committee is currently exploring ways to create a single number rating for spaced object arrays. A status update of proposed revisions to ASTM C423 will be shared. IP Units are substituted for SI Units in this abstract for the sake of clarity. [Eric Wolfram serves as Laboratory Manager for Riverbank Acoustical Laboratories and is currently Chair of the ASTM E33 Committee on Building and Environmental Acoustics. https://www.astm.org/COMMITTEE/E33.htm]
Acoustical performance and operation of the Maxxon acoustical laboratory
Authors: Lilly Jerry G. , Way Evelyn
Published: November 2021

This third and final presentation will cover the acoustical performance of the Maxxon facility including: (1) background noise from exterior sources (e.g., truck traffic serving an adjacent business and train traffic from a nearby railroad) and HVAC systems serving the building, (2) sound isolation from nearby spaces including the adjacent work area and control room), (3) reverberation times with and without the low frequency absorbers, (4) ASTM room qualification with fixed microphones in both rooms, and (5) flanking noise limits of the facility. The operation of the laboratory will also be discussed including a description of the trolly mechanism that transports floor-ceiling test specimens from the adjacent work room and storage area through the double doors into and out of the upper reverberation room, test panel installation details, and managing measurement uncertainty.
Experimental evaluation of a sound diffuse field in a ordinary room
Authors: Rakotonarivo Sandrine T. , Roggerone Vincent , Caisson Antoine , Bottero Alexis
Published: November 2021

This paper presents a methodology based on analysis of spatial correlation functions for assessing diffusivity of a sound field in reverberant and ordinary reflective rooms. A set of sound field measurements using a microphone array is performed in a room excited by a broadband signal and for many positions of loudspeakers. Each recorded signal is then broken down with a filter bank and the spatial correlation of each obtained band-limited signal is computed. Theoretical predictions of the spatial correlation function and the measured ones show very good agreement when spatial averaging and frequency conditions are met for producing a diffuse field. Evolution of the spatial correlation functions versus frequency and number of spatial averaging, i.e., number of sources positions, are examined in a reflective room. Results show that the proposed technique allows to determine the minimum number of required source positions and the actual lower frequency bound for considering that the field is diffuse. The latter is analogous to the Schroeder frequency for reverberant room. Interest of the presented methodology is its ability to experimentally assess in any reflective ordinary room the actual frequency range over which the field can be considered as diffuse. [Work funded by the AMIDEX Foundation.]
Underwater noise produced by anthropogenic activities on Vancouver Island, British Columbia
Authors: Murchy Kelsie , Vagle Svein , Juanes Francis
Published: November 2021

In recent decades shipping traffic has been increasing, leading to elevated ambient underwater noise. Extensive research has been conducted on the changes to ambient noise levels of moving ships, but little is known for ships at anchor. Vancouver Island, British Columbia has many anchorage locations where freighters stop prior to entering the Port of Vancouver. Additionally, Vancouver Island has logging activities that occur in estuaries and surrounding waters. These human activities raise concern about what impacts they might be having on the soundscape and marine organisms that inhabit these key locations. Cowichan Bay, BC is an industrialized bay and a key migration corridor for Pacific Salmon (Oncorhynchus spp.). To understand changes to the ambient noise levels in Cowichan Bay, with different anthropogenic activities, seven stationary hydrophones were deployed during Fall 2019 and 2020. Results show substantial changes in the soundscape with both anchored freighters and logging activities for the duration of their presence in the bay, with elevated SPL detected throughout the bay for anchored freighters. Our results demonstrate the impact anchored freighters and logging activities have on underwater soundscapes and are the first step in understanding the impact these activities have on marine organisms and important ecosystems.
The cabled observatory vent imaging sonar deployed on the Ocean Observatories initiative’s cabled array
Authors: Xu Guangyu , Jackson Darrell R. , Bemis Karen , Ivakin Anatoliy N.
Published: November 2021

The Cabled Observatory Vent Imaging Sonar (COVIS) was installed on the Ocean Observatories Initiative’s Cabled Array observatory at ASHES hydrothermal vent field on Axial Seamount in July 2018. Diffuse hydrothermal flows are identified by maps made using the standard deviation of thephase change between pings separated in time by fractions of 1 s. The results demonstrate significant influences of ocean tides and bottom currents on diffuse hydrothermal discharge. The same data are used to estimate diffuse heat flux, providing two-dimensional maps of heat flux density at a rate of one per day. Sonar data are also used to generate three-dimensional backscatter images of the buoyant plumes above major sulfide structures. These backscatter images show substantial changes in plume bending in the presence of ambient currents and potentially the variations of outflow fluxes. The intensity of acoustic backscatter decreases significantly for highly bent plumes as compared to nearly vertical plumes, reflecting enhanced mixing of plume fluids with seawater driven by ambient currents. A forward model of acoustic backscatter from a buoyancy driven plume yields a reasonable match with the observation, paving the way for inversely estimating the source heat flux of a hydrothermal plume. [Work sponsored by NSF.]
Boundary Pass underwater listening station cabled hydrophone array system
Authors: Hannay David E. , Cole Art , Hennessey Jack
Published: November 2021

An advanced cabled real-time underwater listening station was deployed in May 2020 in Boundary Pass, British Columbia, Canada, to measure underwater radiated noise of commercial vessels and to detect and track vocalizing marine mammals. This system was sponsored by Transport Canada and is operated jointly by Vancouver Fraser Port Authority and JASCO Applied Sciences (Canada) Ltd. The system consists of two synchronized tetrahedral hydrophone arrays, each with 1.65 m hydrophone spacings, deployed 300 m apart on the seabed in 190 m water depth. The hydrophone frames are connected to shore by two 2.8 km fiber-optic cables, and also support ADCP and CTD sensors, sound projectors for calibrations, and video cameras. The Boundary Pass location was chosen because of its relatively deep water and because the major inbound and outbound commercial shipping lanes leading to Vancouver become narrow and adjacent here, allowing acoustic measurements of ships passing in both directions. In this presentation we will discuss the system technical design and sensor specifications. We will also discuss its deployment and the data processing and presentation systems, with a brief overview of the substantial measurements obtained in the first full year of operation.
The neural adjoint method and its application to sound speed learning
Authors: Jin Jihui , Durofchalk Nicholas C. , Saha Priyabrata , Romberg Justin , Mukhopadhyay Saibal , Sabra Karim G.
Published: November 2021

Ray-based acoustical tomography typically provides estimates of local ocean sound speed profile (SSP) fluctuations from precise measurements of acoustic travel times (AT) 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. Classically, inverting the forward model (if available) yielding SSPs from ATs can be done by computing the pseudo-inverse (expensive) or using an iterative-method (e.g., gradient descent); however, including any acoustic forward model (e.g., ray-tracing) in an optimization loop is non-trivial because the nonlinear mapping between SPP and AT is computationally expensive to differentiate. Instead, we use a Neural Adjoint (NA) approach [Ren et al., NeurIPS (2020)] to circumvent this problem by replacing the physics-based forward model with a deep neural network approximation, allowing for an inexpensive way to compute a gradient through backpropagation. The iterative nature of the NA method permits thorough exploration of the solution space depending on the initialization, as opposed to outputting a single point estimate. Here, we continue the discussion of data-driven methods presented in the companion presentation by Saha et al. and show that NA has the potential to further refine existing data-driven SSP estimation techniques.
Examining influence of primary frequency ratio on distortion product otoacoustic emissions generation using an alternating frequency/time domain cochlear model
Authors: Wen Haiqi , Meaud Julien , Dong Wei , Meenderink Sebastiaan
Published: November 2021

Distortion product otoacoustic emissions (DPOAEs) are sounds measured in the ear canal in response to a two-tone stimulus. Because DPOAEs are measured non-invasively, they have been intensively studied and widely applied for the clinical assessment of hearing function. In this work, we combine a three-dimensional computational model with mechanical-electrical-acoustic coupling with in vivo measurements of the pressure in scala tympani and the extracellular electrical outer hair cells (OHCs) response to study distortion product (DP) generation by OHCs in the gerbil cochlea. An efficiency non-linear frequency domain algorithm is used to simulation the nonlinear response of the cochlea in response to a two-tone stimulus. The influence of primary frequency ratio (on IDP generation and propagation is examined. The results show the IDPs are broadly generated by OHCs but their contribution to OAEs are spatially restricted. This work not only improves our understanding of the role of the OHC electromotility in DP generation, but will also benefit clinical noninvasive hearing assessment based on otoacoustic emissions.
Counting the steps for a loudness scale
Authors: Nizami Lance , Barnes Claire S.
Published: November 2021

It is a century-old desire to construct a scale for loudness. Such a scale’s intervals would, on face value, be just-noticeable changes in loudness. Those changes correspond to empirical just-noticeable-differences (jnds) in RMS sound-pressure-level. Hence, a putative loudness scale is the cumulative number of jnds, counted upward from an auditory stimulus’s absolute detection threshold (i.e., the just-perceptible stimulus). Jnd-counting has been intermittently pursued for over a century. The historical method is mathematical integration, but integration inherently assumes infinitely fine jnds, an absurdity. A novel, discrete method of jnd-counting was pioneered for hearing by Dallos and Carhart, after a step-counting method developed for genetics by the polymath J. B. S. Haldane. Nonetheless, one element of the integration method remains necessary: an equation for jnd versus stimulus level. The literature offers such equations in hearing, vision, and the other senses. Unfortunately, Dallos and Carhart omitted crucial details from their exposition, and employed a unique approximation for the jnd, expressing it versus decibels above absolute detection threshold, rather than versus RMS sound-pressure-level. Perhaps consequently, the method lacked acceptance. Here, the method is clarified by generalizing through full details, and then applied to a variety of jnd equations. Non-constant loudness intervals can be accommodated, if desired.