bluuebunny/crossref_metadata_2025 huggingface dataset:
Using wavelets to compress underwater acoustic data from the Gulf of Mexico
Authors: Landeche Avery C. , Sciacca Bradley J. , Howe Brandon , Pies Shaun , Leftwich Kendal , Ioup Juliette W.
Published: November 2022

This research investigated characteristics of the ocean, specifically in the Gulf of Mexico, to find the best wavelet to use for compression of the recorded data. Recorded underwater acoustic data as well as other types of oceanic data were studied. The power spectral density before and after wavelet decomposition, compression, and recomposition (decompression) are compared to assess the quality of the compression. This research describes a method to choose the best wavelet to analyze ocean acoustic data, with future use in the study of sea surface temperatures and heights (tides). [This material is based upon work supported by the National Science Foundation REU program under DMR-2049188, and partially funded by the Naval Research Laboratory-Stennis Space Center.]
Lateral impact noise I: Theory and application
Authors: Dong Wayland , Lo Verde John , Rawlings Samantha
Published: November 2022

Impact noise insulation has traditionally been thought of mostly in terms of vertical adjacencies. However, impact noise is transmitted in all directions though a building, and lateral and diagonally adjacent impact noise transmission can be significant. Lateral and diagonal impact transmission is a one-junction structural flanking path and is, therefore, amenable to statistical energy analysis-based calculation methods such as ISO 12354. In this paper, we review the relevant results from structural flanking path calculations and show how this provides a framework for understanding major features of lateral impact noise transmission such as the frequency dependence and effect of structure type. In turn, measurement of lateral impact noise provides a method of estimating the vibration reduction across junctions. These findings are illustrated with examples from field testing.
Field study of bats in Brunei Darussalam
Authors: Webster Cara , Tuninetti Amaro , Granger Jesse , Su'eif Syafi'ie , Ariffin Ibnurrafiq , Grafe Ulmar , Müller Rolf
Published: November 2022

Studying model organisms in their natural environments is essential for advancing bioinspired science and technology. Echolocating bats can be models to inspire new technology for sonar sensing, mobility with flapping flight as well as the integration of these two capabilities. Bat species belonging to genera such as Rhinolophus and Hipposideros stand out for their ability to navigate and hunt prey in dense vegetation. To further the study of echolocation and flight strategies in these genera, field-based research methods have been used to observe, record, and capture bats in Brunei Darussalam. This work was conducted at Andulau Forest Reserve on the border of Belait and Tutong Districts, various other field sites in Tutong District, as well as at Mata Mata in Brunei-Muara District from June 2022 through August 2022. Harp traps were primarily used to capture bats, a less invasive capture technique compared to other types of netting and thought to be more effective against the sophisticated echolocation capabilities of these bats. Acoustic recordings were collected at trap sites and upon processing. These recordings can be utilized to advance passive acoustic monitoring and to improve software that can distinguish species based on sonar characteristics which can also support general biodiversity monitoring.
Impact of environmental factors on the variability of the avian dawn chorus
Authors: Moore Kelsey B. , Moats Levi T. , Cook Mylan R. , Hall Lucas K. , Gee Kent L.
Published: November 2022

The avian dawn chorus is especially prominent during the spring and summer when birds are breeding. The short-term and seasonal variation (timing, level, duration, and spectrum) of the avian dawn chorus is not well understood, and this study represents an initial effort to correlate changes in different chorus characteristics with different environmental variables. Acoustical data were gathered with a Larson Davis Sound Level Meter at the U.S. Fish and Wildlife Service Bear River Migratory Bird Refuge from March through August 2021 and 2022 and were analyzed for variation in start time and acoustical characteristics. Although it has been shown that the chorus start time is roughly correlated with civil twilight, we found that they ranged from 3 h before nautical twilight to half an hour after. Additionally, daily maximum SPL during a dawn chorus can vary during the peak breeding season by more than 40 dB. We analyzed the effect of several environmental variables on the dawn chorus, including nearby water levels, cloud coverage, wind, etc., as well as overall seasonal variation. Our findings highlight the importance of water and demonstrate the need for continued research and analysis of daily variation. Results will be discussed.
The coordinated arctic acoustic thermometry experiment—CAATEX
Authors: Dzieciuch Matthew A. , Sagen Hanne , Worcester Peter F. , Storheim Espen , Colosi John A. , Krishfield Richard A. , Sandven Stein , Geyer Florian
Published: November 2022

The coordinated arctic acoustic thermometry experiment (CAATEX) was a joint U.S.-Norwegian trans-Arctic acoustic propagation experiment with a design comparable to the 1994 TransArctic Propagation (TAP) experiment. The goal was to measure the changes in low-frequency sound propagation due to changes in ocean heat content and salinity, and ice conditions. Two 35 Hz acoustic transceiver moorings, one in the Nansen Basin and one in the Beaufort Sea, were deployed along with four other receiving moorings. All six moorings were equipped with vertical hydrophone arrays, recording transmissions every 36 h from fall 2019 to fall 2020. Each mooring also recorded temperature and salinity time series along the vertical extent of the hydrophone arrays, ice thickness using an upward-looking sonar, and ocean bottom pressure. The acoustic travel-times allow comparison of present-day heat content to the 1994 measurement, but there are several other points of comparison that are sensitive to environmental changes. These include transmission loss, acoustic scattering, and the acoustic arrival structure. These measurements of ocean and ice processes, and the acoustic propagation and ambient sound will improve our ability to monitor, communicate, and navigate in the Arctic Ocean.
Assessment of transfer learning ultrasound elastography: A breast cancer phantom study
Authors: An Justin , Abdus-Shakur Tasneem , Denis Max
Published: November 2022

In this work, a phantom study is performed to investigate the feasibility of quantitative tissue stiffness assessment of breast cancer masses using transfer learning ultrasound elastography. A transfer learning ultrasound elastography model is developed to classify the breast masses into quantifiable Young’s modulus (kilopascals, kP) values. The transfer learning model combines features of B-mode images and elastograms from Google’s deep learning model AlexNet. The B-mode images and elastograms from a calibrated phantom with elastic inclusions are used to train and validate the model. Thereafter, the model is used to quantify Young’s modulus of inclusions from an uncalibrated breast phantom. The accuracy of the transfer learning results with and without the inclusion of the B-mode is discussed.
Particle image velocimetry for estimating shear wave elasticity imaging (SWEI) in the esophagus dysplasia
Authors: Lin Wei-Cheng , Ou Ruei-Wen , Liu Hsiao-Chuan , Wu Jian-Xing
Published: November 2022

In this study, a 128-channel high-frequency pulse generator/receiver system was used to emit multi-angle wave propagation, and the generator plane excitation was used to generate a focused beam, which induced the phenomenon of particle displacement in the esophagus phantom recorded. Shear wave electrography is generated by using a micro-ultrasound probe (ARFI), which excites the shear waves with the output acoustic energy. In addition, we perform the method of PIV proper orthogonal decomposition to better qualify and quantify the differences between the PIV and Doppler, especially for analysis block into PIV for particle tracking, in which the external environment, with a Doppler similarity index of 82%, and PIV mainly uses the Doppler algorithm for analysis and obtains 97 frames, and fixed 0.33 ms time difference to output pictures. Each pass interrogation area is set to 128 in sequence, the distance is defined in calibration, in which the low filter contrast of image-based validation is set to 0.004, and the bright filter objects are set to 0.5. Through the analysis results of PIV, each particle's speed and movement are critical for the hospital to think. The relative position of the lesion and the effect of ARFI on the lesion are to be understood by understanding the direction of movement of the contrast agent. Overall, the shear wave and Doppler output amplitudes provided the best image quality and PIV results for esophagus dysplasia.
Low-frequency directional characteristics of a gamelan gong
Authors: Bellows Samuel D. , Harwood Dallin T. , Gee Kent L. , Leishman Timothy W.
Published: November 2022

The structural modes of gamelan gongs often have clear impacts on their far-field directivity patterns with the number of directional lobes corresponding to the associated structural mode shapes. Many of the lowest modes produce dipole-like radiation with the dipole moment determined by the positions of the nodal and antinodal regions. Spherical harmonic and multipole expansions facilitate further understanding of the gongs' low-frequency directional characteristics. The expansions also yield practical simplifications to model their radiation.
NASA quesst mission—Site selection process for community testing
Authors: Shah Gautam H. , Czech Joseph J. , Richwine David M.
Published: November 2022

The National Aeronautics and Space Administration (NASA) has committed to deliver data to the International Civil Aviation Organization’s Committee on Aviation Environmental Protection (ICAO CAEP) defining community response to sounds from supersonic aircraft designed such that their sonic boom is replaced with a soft “thump” sound. NASA is developing the X-59, a unique research aircraft capable of quiet supersonic flight, and will use the aircraft in a series of four to six community overflight tests (2024–2026) to measure acoustic levels of its “sonic thump” and related public response in support of the agency’s commitment to ICAO. Unlike most NASA flight research, which is conducted primarily at the agency’s facilities, the community tests will occur at various locations across the contiguous United States and involve flight over the general population in order to obtain a nationally-representative dataset. The process for identifying both the airfields and community test locations involves multiple operational and technical considerations relative to both aircraft and data collection requirements, including flight operations, geographic, and climate diversity as well as population demographics. This presentation provides an overview of the ongoing selection process being applied to address those considerations while ultimately ensuring an representative community response dataset.
Generalized inverse problems in resonant ultrasound spectroscopy
Authors: Olejnak Juraj , Sedlak Petr , Seiner Hanus , Zoubkova Kristyna , Stoklasova Pavla , Grabec Tomas
Published: November 2022

Determination of the elastic constants by RUS is an inverse problem because experimentally obtained resonant frequencies cannot be directly recalculated into the elastic constants. Instead, an approximate spectrum is calculated from the dimensions and crystallographic orientation of the sample, its mass, and a set of 'guessed' elastic constants, and the difference between this approximate spectrum and the experiment is iteratively minimized. RUS has been used for the determination of either the elastic constants, or crystallographic orientations of the material in the past, but the recent advancements in RUS methodology, in particular, the employment of the scanning laser vibrometry for identification of the vibrational modes, enable inverse determination of most of the input parameters simultaneously. We propose an extension of the classical RUS inversion procedure that allows us to precisely identify the crystallographic orientation and dimensions of the sample in addition to the elastic coefficients. The proposed algorithm was applied to generally oriented iron single crystals. After the shape and orientation optimization, we achieved an unprecedented match between calculated and measured spectrum, including a very high number of utilized resonant modes (>300). We show that the highest modes are extremely sensitive to the crystallographic orientation.
Principal component analysis for complex geometry modal identification
Authors: Beardslee Luke , Ulrich Timothy J. , Shokouhi Parisa
Published: November 2022

Recent advances to resonant ultrasound spectroscopy (RUS) to include finite element methods (FERUS) have expanded its application to more complex geometries. When measuring a sample of complex geometry, it is often challenging to retrieve all modal information from a single point, this is due to the complexity of the mode shapes and likeliness of landing on a node location. To capture all the modal information, many measurement points are used to superimpose into a final resonant spectrum, and these measurements points are often based on intuition or experience. The work presented in this abstract proposes a simple method of finding crucial measurement locations on a complex sample using singular value decomposition (SVD) and principal component analysis (PCA). Applying SVD to a group of forward calculated eigenvectors, a set of measurement locations can then be extracted from the high amplitude locations identified from the subset of eigen images. This method of PCA for mode identification has been shown to accurately identify essential measurement locations.
Objective discrimination of bimodal speech using the frequency following response: A machine learning approach
Authors: Eng Erica , Xu Can , Medina Sarah , Cheng Fan-Yin , Gifford René , Smith Spencer
Published: November 2022

Bimodal hearing, which combines a cochlear implant (CI) with a contralateral hearing aid, provides significant speech recognition benefits relative to a monaural CI. Factors predicting bimodal benefit remain poorly understood but may involve extracting fundamental frequency and/or formant information from the non-implanted ear. This study investigated whether neural responses (frequency following responses, FFRs) to simulated bimodal signals can be (1) accurately classified using machine learning and (2) used to predict perceptual bimodal benefit. We hypothesized that FFR classification accuracy would improve with increasing acoustic bandwidth due to greater fundamental and formant frequency access. Three vowels (/e/, /i/, and /ʊ/) with identical fundamental frequencies were manipulated to create five bimodal simulations (vocoder in right ear, lowpass filtered in left ear): Vocoder-only, Vocoder +125 Hz, Vocoder +250 Hz, Vocoder +500 Hz, and Vocoder +750 Hz. Perceptual performance on the BKB-SIN test was also measured using the same five configurations. FFR classification accuracy improved with increasing bimodal acoustic bandwidth. Furthermore, FFR bimodal benefit predicted behavioral bimodal benefit. These results indicate that the FFR may be useful in objectively verifying and tuning bimodal configurations.
Directional passive acoustic structures inspired by the ear of Achroia grisella
Authors: Díaz-García Lara , Reid Andrew , Jackson-Camargo Joseph , Windmill James
Published: November 2022

The need for small directional microphones is patent in the current market. From smartphones to hearing aids, a small microphone capable of rejecting ambient noise is highly desirable. Most MEMS microphones are omnidirectional and have to resort to arrays to achieve directionality, effectively counteracting the reduced size that they offer in the first place. For this reason, we use bio-inspiration and turn to nature to find examples of solutions to this problem. The female specimens of the moth Achroia grisella are capable of monoaural directional hearing, which they use to track the males’ mating calls. It is believed that they achieve directionality solely due to the morphology of their tympana. To test it, we first produce a multiphysics simulation of the structure that serves as a starting point. For experimental measurements, additive manufacturing is chosen for its ease and cost-efficiency. 3D-printed samples of the same model are examined through micro-CT scanning and then measured using laser-Doppler vibrometry to determine their frequency and directivity responses. The results of both approaches are compared, and it is found that the structure does indeed show directionality with the second eigenfrequency showing a hypercardioid-like pattern towards the front of the moth.
Modular speaker design enabled by multi-material additive manufacturing
Authors: Lawrence A. J. , Allison Jared , Naify Christina J.
Published: November 2022

One of the most promising features of additive manufacturing is ability to reduce part count and assembly by printing complex shapes. This feature is further highlighted by utilizing multi-material printing in which stiff and compliant materials can be deposited by the same system. Air-acoustic speakers are traditionally comprised of several assembled components with different material properties including a stiff enclosure, stiff diaphragm, and compliant suspension. In this presentation, we will describe a modular acoustic speaker design. The design consists of fully printed structural components (which are threaded together, and assembled with a voice coil and magnet). The basic design as well as printing process will be described and acoustic measurements reported. A range of printed designs, which can be interchanged among each-other will be presented, and future design ideas which take advantage of the printing process explored.
Healthcare communication in acoustical consulting practice
Authors: Davenny Ben , Odom Alex
Published: November 2022

With respect to speech communication in healthcare facilities, acoustical consultants are often concerned with overheard speech in the context of patient privacy. Low background sound is often a culprit with speech privacy problems, and examples will be given in exam rooms and common areas. Case studies of both poor speech privacy and poor speech communication will be given along with proposed solutions. Finally, popular science communications from the authors’ corporate blog during the COVID pandemic on speech communication and personal protective equipment will be discussed.
Ambient noise characteristics in long-term care facilities
Authors: Puckett Brian J. , Ryherd Erica E. , Bent Tessa , Baese-Berk Melissa M. , Manley Natalie
Published: November 2022

The built environment in senior living communities can enhance or detract from a resident’s quality of life. This work focused on one specific physical characteristic of the environment that has not been well documented in recent literature: noise. Noise can negatively impact patient-caregiver speech communication—a paramount aspect of healthcare delivery. A communication breakdown can be particularly problematic among older adults, a population that can have a higher incidence of sensory impairments or cognitive decline. In this study, ambient noise data were collected at several senior living communities. Sound level meters were deployed in various locations across the facilities, including resident rooms, common lounge areas, nurse stations, therapy rooms, staff break rooms, and corridors. Noise data were collected over 72-hour periods during both weekdays and weekends to understand typical acoustical conditions of senior living communities during different levels of activity, occupancies, and times of day. The findings aid in understanding what acoustical conditions exist in senior living communities, such as overall sound levels, fluctuations over time, and spectral content, and how these conditions can impact healthcare speech communication for aging populations.
Manifold learning for global active noise control: Sensor interpolation
Authors: Lai Bo-Ru , Chen You-Siang , Bai MingSian
Published: November 2022

To achieve global control, unmeasured frequency responses (FRs) of a control source and preselected control points are required. In this paper, sensor interpolation (SI) approaches based on plane wave decomposition (PWD), kernel ridge regression, deep neural network (DNN) are presented. A broadened control region encompassing a large number of measured and fictitious control points can be obtained using the SI techniques. PWD is a two-stage procedure that begins with trimming down plane wave components, followed by an extraction of the associated complex amplitudes. In kernel ridge regression, a reproducing kernel in the Hilbert space (RKHS) is utilized to interpolate continuous relative transfer functions. The DNN-based SI approach is inspired by the kernel method. Convolutional neural networks and the like are exploited to interpolate the FRs at the fictitious points. Simulations are conducted for a thirty-microphone uniform linear array. From the results, an excellent fit between the FRs at the fictitious points and the ground truth generated by the image source method can be obtained below the spatial aliasing frequency. The efficacy of the interpolated FRs in relation to global control is demonstrated via an example of feedforward active noise control using a linear loudspeaker array.
A multi-channel hear-through filter design approach and its applications
Authors: Kim Juhyung , Zhuang Yongjie , Liu Yangfan
Published: November 2022

Sound characteristics change when propagating through materials and structures, such as vehicle cabins or space partitions. These structures usually block the sound propagation path and cause significant distortion to the sound heard by the other side of the structures while, in many applications, clear speech communication is needed. Especially during the Pandemic of Covid-19, it has become common to have space partitions at face-to-face service locations, for example, places providing food or banking services, for the prevention of virus spread. However, the degraded conversation sound quality caused by these partitions can negatively affects the service quality. A multi-channel active hear-through system is developed in the current work to provide a solution to provide more realistic sound environments for conversation through partitions which can preserve both the spectrum and the spatial distribution of the original sound field. This would also be useful for the improvement of augmented reality experiences and sound transmission quality in divided spaces. Compared with a direct inverse filter design, the coupling effect across channels and the superposition effect of original and reproduced sound are considered in the proposed method.
“Mud acoustics” and the ocean acoustics program
Authors: Becker Kyle M. , Headrick Robert H. , Weber Thomas C.
Published: November 2022

Shallow water acoustics is one of the major thrusts of the Office of Naval Research Ocean Acoustics Program and has been an important area of interest to Navy programs since at least the work of Pekeris, Ewing, and Worzel in the 1940’s. In the 1950’s and early 1960’s, there was a flurry of activity both in the US and UK focused on propagation within and reflection from the seabed and the acoustical characteristics marine sediments. This work formed the basis of a research program carried out by the applied ocean acoustics branch of the acoustics division at the Naval Research Laboratory in the 1970’s. In April 1991, with the Cold War coming to an end, and a shift in interest from blue water to the littorals, ONR sponsored a workshop on shallow water acoustics at the Woods Hole Oceanographic Institution. This meeting, including underwater acousticians, geologists, geophysicists, and physical oceanographers, largely set the stage for the next 30 years of shallow water acoustics research supported by ONR. Prominent efforts include the ONR Geoclutter Program and the Shallow Water 2006 experiments, both focused on regions dominated by sandy bottoms. This talk describes more recent efforts in regions characterized by muddy bottoms.
Quantifying data information content to resolve seabed structure in geoacoustic inversion
Authors: Dosso Stan , Holland Charles W. , Bonnel Julien , Tollefsen Dag , Jiang Yong-Min , Dettmer Jan
Published: November 2022

This paper considers the importance of quantitative model selection and general parameterizations in estimating and interpreting seabed profiles in geoacoustic inversion, with application to data collected on the New England Mud Patch. In particular, the seabed structure that can be resolved depends on the information content of the acoustic data set under consideration, which varies with a number of factors, including the physics of the seabed acoustic interaction, frequency content of the data, and measurement and theory errors. Quantitative model selection applied to general parameterizations ensures the inclusion of seabed structure that is reliably sensed by the data while avoiding spurious structure. Data sets considered here include ship noise, modal dispersion, and wide-angle reflection coefficients. In each case, seabed models consistent with the data information content are estimated as part of the inversion using trans-dimensional and/or Bernstein-polynomial parameterizations. Results for all data sets indicate a low sound-speed mud layer over higher-speed sand; however, the ability to resolve structure within the mud layer, such as a transition to higher speeds near the mud base and possibly a weak positive gradient in the upper mud, depends on the information content of the various data sets. [Supported by the Office of Naval Research.]
Measurement of recording studio control room operational response for various audio monitor configurations using a binaural artificial head
Authors: Mattos Tiago F. , Brooks Bennett M.
Published: November 2022

The primary technical recommendations for measuring the Operational Room Response Curve (ORRC) in a recording studio control room, given in EBU-TECH-3276 and ITU BS.1116, imply the use of a single microphone located at the “reference listener position” as well as other “worst case” locations. It is known that the results of measuring the ORRC in this way can differ significantly for only one audio monitor (loudspeaker) operating compared to the two monitors required for stereo, and for multichannel immersive audio configurations, such as Dolby Atmos. These differences can alter the way that program material will be perceived by the studio users (mix and master engineers) who employ two ears to make production decisions, not one! It is proposed to use a binaural artificial head system for ORRC measurements, to better simulate real-world listening conditions. This research analyzes and compares the measurements of the ORRC made using the standard single microphone locations to measurements made using a binaural artificial head, for various monitor configurations. The impact of these findings on the decision quality for the studio user will be addressed.
Non-cuboid iterative room optimizer
Authors: D'Antonio Peter , Petrolli Rinaldi P.
Published: November 2022

The growing processing power of desktop and distributed cloud cluster computing is playing a larger role providing computational architectural acoustic solutions. This presentation will provide a status update on the Non-cuboid Iterative Room Optimization software called NIRO. It offers an iterative approach to full bandwidth optimization of critical listening rooms. The program uses a finite element method (FEM), image source model (ISM), and non-dominating sorting genetic algorithm (NSGA) to simultaneously optimize the room geometry of any shaped room, including boundary admittances, for any number of listeners and loudspeakers. It minimizes the weighted sum of the modal response and speaker boundary interference response, the spatial uniformity around the mix position and reflections in the reflection free zone (RFZ). With an optimal room setup, acoustical diffusors and absorbers with a specified resonant frequency, bandwidth, and efficiency are added to the model to optimize the acoustic properties. A combination of FEM, ISM, and an additional geometrical acoustics model is used to generate full bandwidth impulse responses. The RFZ, envelopment, reverberation time, low-frequency response, and temporal decay are optimized and evaluated. Following the addition of HRTFs, stereo auralization can be generated. Proof of performance and application examples will be presented.
The evolution of Blackbird Studio C
Authors: D'Antonio Peter , Maassenburg George
Published: November 2022

Starting in 2002 John and Martina McBride set out to create several small rooms, each one unique in design and technology. George Massenburg (GM) was asked to coordinate the design of one of the rooms and given the mandate to make it the most advanced room imaginable. GM specified that the room should offer an accurate monitoring environment for more than one listener, a reasonable presentation of how materials will sound in multiple circumstances outside of the space, a flexible environment that doesn’t compromise musical and artistic contexts, an accurate representation of virtual sources (sources spread across one or more loudspeakers) to more than one listener, a room with linear, supportive ambience, which as much as possible, has near-equal decay rates across as much of the frequency spectrum as possible. In June 2004, GM contacted Peter D’Antonio with a proposal to collaborate on a new surround music monitoring/control/recording room, which became Studio C. The resulting diffusor design covering all four walls and ceiling, with corner bass absorption, will be presented. Since opening the room has been used successfully and has recently installed a Dolby Atmos system. The presentation will also present user perceptions from 2005 to the present.
Determining the spatial and temporal variability of false killer whales (Pseudorca crassidens) and short-finned pilot whales (Globicephala macrorhynchus) in the Hawaiian Islands from passive acoustic monitoring
Authors: Madrigal Brijonnay , McCullough Jennifer L. , Lammers Marc , Oleson Erin , Bejder Lars , Pacini Aude
Published: November 2022

False killer whales (Pseudorca crassidens) and short-finned pilot whales (Globicephala macrorhynchus) are resident, toothed whale species to the Hawaiian archipelago. False killer whales are considered of high concern in Hawai‘i with the insular population listed as endangered. Passive acoustic monitoring (PAM) is an effective technique for studying these highly social odontocete species on large temporal and geographical scales. Moored hydrophones were deployed inside and outside Marine Protected Areas (MPAs) through the SanctSound project, allowing leveraging of long-term datasets to assess the acoustic behavior of these species within and beyond the Hawaiian Islands Humpback Whale National Marine Sanctuary and Papahānaumokuākea Marine National Monument. High Frequency Acoustic Recording Packages (HARPs) (200 kHz SR) and SoundTraps (48 kHz SR), recording on various duty cycles, were deployed between 2018–2022 within MPAs (monument: n = 51 months; sanctuary: n = 76 months) and outside MPAs (n = 60 months). PAMGuard detectors were used to detect whistles, clicks, and burst pulses. Detection features were extracted using the PAMpal package and events classified to species using BANTER. Acoustic monitoring provides key information about the value of MPAs and a better understanding of habitat use and behavior of these species.
Under-ice 4-8 kHz acoustic transmission and communication in ducted environments in the Arctic Ocean
Authors: Tollefsen Dag , van Walree Paul , Jenserud Trond , Forsmo Vidar
Published: November 2022

Underwater communications and navigation for small platforms can typically involve acoustic systems operating at kHz frequencies. For under-ice applications, this motivates studies of acoustic transmission in present-day Arctic conditions. This paper presents data from recent mid-frequency (4–8 kHz) under-ice acoustic transmission and communication experiments to ∼10 km range in the Nansen Basin and in the Beaufort Sea of the Arctic Ocean. For shallow sources and receivers, delay profiles show early arrivals due to ducted paths followed by a group of strong arrivals due to bottom-interacting paths. The relative amplitudes of these groups depend on duct and under-ice properties. We demonstrate that despite shallow (∼25 m) source/receiver depths, good communication performance can be achieved in these single- and double-ducted environments by exploiting the bottom-interacting paths. Simulations with the Bellhop ray model support the findings.
Environmentally adaptive acoustic communication and navigation for underice autonomous operation
Authors: Schmidt Henrik
Published: November 2022

The Arctic acoustic environment has changed dramatically, with multi-year ice being less abundant and the influx of warmer Pacific water, the so-called “Beaufort Lens,” creating a local maximum in the sound speed at a depth of 50–80 m. In contrast to the classic Arctic sound speed profile which had a monotonic increase in sound speed yielding a surface duct with strong ice interaction, the warm water lens creates a lower duct supporting extremely efficient propagation to long ranges. On the other hand, this double duct environment is decremental to short range communication and navigation of underwater vehicles. Thus, for a transmitter in one channel, the lens creates distinct shadow zones in the other channel at ranges between 1 and 4 km, which are the typical operational ranges of small AUVs, severely affecting navigation and communication performance. In addition, the temporal variability of is significant due to internal waves. During ICEX20 MIT and WHOI demonstrated an integrated communication and navigation concept where a network of ice-moored modem buoys with GPS tracking were used to track an under-ice AUV using regular CTD updates of optimal ranging, which in combination with a novel dynamic model constrained navigation fusion engine demonstrating GPS-grade navigation accuracy over several hours of operation. Using an EOF framework for updating the onboard environmental awareness on the AUV, the concept supports autonomous depth selection for optimal communication connectivity. [Work supported by ONR and UWDC/ASL.]
Ocean acoustic tomography in the Beaufort Gyre
Authors: Vazquez Heriberto J. , Cornuelle Bruce D. , Worcester Peter F. , Dzieciuch Matthew
Published: November 2022

An ocean acoustic tomography array with a radius of 150 km was installed in the central Beaufort Gyre during 2016–2017 for the Canada Basin Acoustic Propagation Experiment (CANAPE). Five transceivers were deployed in a pentagon shape with a sixth transceiver at the center and a long vertical receiving array northwest of the central mooring. At least 12 refracted-surface-reflected (RSR) ray arrivals with lower turning points at depths between 500 and 3500 m were resolved in the acoustic receptions at all receivers. Travel-time anomalies were computed relative to a range-dependent sound-speed reference made by objectively interpolating annual-average sound-speed profiles constructed from the temperature data at each mooring. The travel time anomalies were inverted to estimate the 3-D sound-speed anomaly, including corrections to the positions of sources and receivers consistent with the uncertainty from long-baseline acoustic navigation systems at each mooring. Although the deep water in the Canada Basin is nearly homogeneous in temperature and salinity and highly stable (slowly warming in response to geothermal heating), it proved necessary to allow for a sound-speed change in the deep ocean to obtain consistent inversions, suggesting that the sound-speed equation at high pressure and low temperature is in error by about 0.1–0.2 ms−1.
Prospects for acoustic remote sensing and acoustic system performance in the Beaufort Gyre region
Authors: Duda Timothy F.
Published: November 2022

In the Beaufort Gyre region north of Alaska, the vertical interleaving of the near-surface temperature maximum, the warm Pacific Summer Water (PSW), the cool Pacific Winter Water, and the Atlantic layer make for unusual acoustic conditions. The dynamics of these upper ocean layers cause typical complex and turbulent-like oceanic flow that causes geographically variable heat content and acoustics. A sound duct in the PWW, below the PSW and above the Atlantic Layer, filling ∼75 to 225 m depth, is prominent but not universal. Erosion of the PSW warm layer by either vertical or horizontal mixing processes often breaks the duct, with an additional seasonal cycle of ducting effectiveness, and allows sound to escape to interact with the scattering and attenuating surface. The duct enables communication and navigation signaling, but with that interruption caveat. It also allows passive sensing, best for sound that enters the duct and moves through it. A challenge is to utilize sound that exists outside the duct. This includes sounds emitted outside the duct by mammals, fracturing ice, or anything else. This sound will either cycle through the duct at steep angle, or stay above the duct and repeatedly reflect from the top boundary. The combination of unducted sound being subject to strong attenuation by ice or wave interaction (the typical high-latitude situation) and high variability of the duct effectiveness, imposes limitations on the usefulness of the otherwise convenient duct.
Deep learning-based super-resolution ultrasound microvascular imaging
Authors: Song Pengfei
Published: November 2022

Super-resolution ultrasound microvascular imaging (SR-UMI) is a fast-growing field that leverages contrast microbubbles (MB) to achieve super-resolution and track blood flow. Conventional SR-UMI is primarily based on MB localization and tracking, which is a challenging task in vivo with complex MB responses subject to various tissue characteristics and imaging settings. Conventional MB localization and tracking approaches based on experimentally calibrated or engineered MB templates typically fall short of capturing the widespread distribution of MB signals in vivo, leading to suboptimal SR-UMI performance. In contrast, deep learning (DL) provides many powerful tools to better represent the complex landscape of MB and blood flow signals that lead to enhanced SR-UMI. In this talk, I will first introduce several DL-based MB localization techniques with discussion on challenges and solutions involving DL training within the context of SR-UMI. I will then introduce several other novel DL-based SR-UMI techniques that do not rely on MB localization or tracking to achieve super-resolution and infer blood velocity. Some of the techniques are contrast-free. In vivo imaging examples from chorioallantoic membrane as well as mouse brain will be presented as validations of the DL-based SR-UMI techniques. In vivo applications in cancer and Alzheimer’s disease will also be presented and discussed in this talk.
Deep-learning based insitu ultrasound thermometry for thermal ablation monitoring
Authors: Anand Ajay , Ramesh Ashwin , Yeo Seungju , Mohammadi Narges , Cetin Mujdat , Dalecki Diane
Published: November 2022

Noninvasive in situ temperature measurement (thermometry) is an attractive means of mapping the region of thermal damage during thermal ablation treatments. Existing methods of ultrasound thermometry are ineffective beyond 50 °C due to multiple physical limitations, including a non-monotonic relationship between temperature and sound speed that reaches a plateau around 60 °C, tissue phase transitions and deformation. An ultrasound-based technology that can monitor treatment over the entire therapeutic temperature range is desirable clinically. This paper describes a deep learning-based approach that uses thermometry data from the periphery of the heating zone (where temperatures are less than 50 °C) to infer temperature throughout the treatment zone. Spatiotemporal 2D temperature maps from 3–12 s HIFU heating exposures (in 0.5 s increments) were generated (using COMSOL) with a subset used for training the network and the rest for testing. Peripheral temperature values (excluding the first 5 mm closest to the axial focus), scalar time values, and a binary flag indicating heating/cooling were inputs to the network, and the temperature profile axially through the HIFU focus was predicted. The temperature prediction accuracy was better than 0.5 °C during heating and cooling. This paper will also address robustness to noise in the input temperature measurements and discuss future directions including experiments with ultrasound backscatter data and strategies to explicitly incorporate heat diffusion physics into the learning paradigm.
Fibrin-targeted phase shift microbubbles outperform fibrin-targeted microbubbles for the treatment of microvascular obstruction
Authors: Pacella John J.
Published: November 2022

Introduction: Mortality from AMI has decreased in recent years; however, microvascular obstruction (MVO) occurs frequently, ultimately limits myocardial salvage, is associated with rising post-AMI CHF, and has no definitive therapy. To address this urgent unmet need, we have developed an image-guided acute therapy, termed “sonoreperfusion” (SRP), that resolves MVO via ultrasound-targeted microbubble cavitation (UTMC). We previously used standard MBs with fibrin-targeting and demonstrated enhanced reperfusion compared to standard MBs with non-targeting. However, phase shift microbubbles are much smaller than standard MBs. Thus, we compared the SRP efficacies of fibrin-targeted phase shift microbubbles (FTPSMB) to standard size fibrin-targeted microbubbles (FTMBs). Methods: MVO of the rat hindlimb was created by injecting microthrombi into the left femoral artery under contrast-enhanced ultrasound (CEUS) guidance. DEFINITY® MBs were infused (2 ml/h) through the right external jugular vein for CEUS. Following 10 min of stable MVO, a transducer was positioned vertically above the hindlimb to deliver therapeutic US pulses during concomitant administration of FTMBs/FTPSMBs (3 ml/h). Results and conclusion: FTPSMB treatment resulted in a greater increase in the blood volume (dB) and flow rate (dB/sec) than FTMB after each 10-minute treatment session owing to their small size and more effective thrombus penetration. Studies to explore the underlying molecular mechanisms associated with SRP treatments are underway
Backscatter techniques for ultrasonic bone assessment
Authors: Hoffmeister Brent K.
Published: November 2022

Osteoporosis is a bone disease that affects hundreds of millions of people worldwide. The name osteoporosis literally means “porous bone” reflecting the changes in bone density and microstructure that lead to increased risk of fracture. Ultrasonic backscatter techniques have been proposed as a way to detect these changes. Backscatter measurements are performed by propagating ultrasonic pulses into bone and receiving signals returned from the porous interior of the tissue. Numerous backscatter techniques have been developed over the last two decades for ultrasonic bone assessment. This presentation reviews many of those techniques and compares their relative performance in a recent in vivo study using measurements at the femoral neck, a common location for osteoporotic fracture.
A mechanistic journey in shock wave lithotripsy research
Authors: Zhong Pei
Published: November 2022

As a remarkable engineering innovation, shock wave lithotripsy (SWL) has revolutionized the treatment of kidney stone disease since 1980s with worldwide clinical acceptance. Over the past three decades, the long journey to understand the transient interaction of focused shock waves with kidney stones and soft tissues has propelled fundamental research at multiple fronts, including (1) the generation, propagation, and interaction of various stress waves inside the bulk stone materials, and surface acoustic waves associated with Mach stem formation at the stone boundary; (2) dynamic fracture and comminution processes in relation to lithotripter field characteristics; and (3) cavitation-induced stone surface erosion and vascular injury. In this talk, I will present illustrative examples to highlight chronologically the progressive understanding regarding the mechanisms of stone comminution and tissue injury, and how the acquired knowledge has influenced the technology evolution and clinical practice in SWL. I will also discuss how the fundamental concepts and techniques of SWL have been widely utilized in other therapeutic ultrasound and lithotripsy applications; and future perspectives, especially related to 3D cavitation detection and monitoring, as well as multi-spark shock wave generator development.
Advancing ultrasound and microbubble-mediated drug delivery in the brain and spinal cord
Authors: O'Reilly Meaghan
Published: November 2022

When combined with intravenously administered microbubbles, ultrasound can transiently open the so-called ‘blood-brain barrier’ (BBB) and ‘blood-spinal cord barrier’ (BSCB), resulting in increased vascular permeability to enable delivery of therapeutics to the central nervous system (CNS). Thus this technique holds transformative potential for patients suffering from CNS disorders. Achieving successful opening of these barriers while mitigating lasting tissue changes requires control over the transmitted sound, as well as knowledge of the interaction of the transmitted sound field with the microbubbles. In this talk I will review contributions made to monitoring and controlling BBB opening, as well as efforts by my group to translate this intervention to the spinal cord. Recent preclinical in vivo findings and ex vivo results in human vertebrae will be reported.
Immersed-boundary time-domain simulation of acoustic pulse scattering from a single or multiple gas bubble(s) of various shapes
Authors: Hou Jiacheng , Zheng Zhongquan Charlie , Allen John S.
Published: November 2022

Acoustic scattering and resonances resulting from a point pulse on a single or multiple gas bubbles are simulated using a time-domain simulation. The time histories of scattering pressure and velocity, both outside and inside the bubbles, are obtained simultaneously with an immersed-boundary method implementation. The acoustic resonances of the bubbles are investigated for various bubble numbers, sizes, shapes and interior gas parameters. For several cases, the scattering and resonance behaviors are compared with the existing theoretical and experimental results.
Investigation of indoor soundscape indicators according to the types of occupants' activity in autonomous vehicles
Authors: Jeon Jin Yong , Lee Haram , Kim Juin , Park Dongchul
Published: November 2022

Electric and autonomous vehicles have brought about a paradigm shift in interior space design and are now replacing their functions as spaces for living, work and leisure activities. Therefore, in order to design the optimal sound environment for the interior space of the vehicle, it is necessary to investigate the interior soundscape of the vehicle based on the type of occupant's activity and the purpose and function of the space. However, although the soundscape concept has been applied to the design of urban and natural spaces and large indoor spaces such as open plan offices, there is no study on the interior space of vehicles. In this study, soundscape indicators were set according to the activity patterns of autonomous vehicle occupants. Through the result, it is possible to derive vehicle interior soundscape design factors based on the evaluation of each type of sound environment presented.