bluuebunny/crossref_metadata_2025 huggingface dataset:
Active control of passive acoustic fields: Passive synthetic aperture/Doppler beamforming with data from an autonomous underwater vehicle
Authors: D'Spain Gerald L. , Terrill Eric , Chadwell C. David , Smith Jerome A. , Lynch Stephen D.
Published: November 2016

Autonomous underwater vehicles (AUVs) equipped with hull-mounted arrays can actively modify received acoustic fields to optimize extraction of information. Ocean acoustic data collected by an AUV-mounted two-dimensional hydrophone array, with overall dimension one-tenth wavelength at 200-500 Hz, demonstrate aspects of this control through vehicle motion. Source localization is performed using Doppler shifts measured at a set of receiver velocities by both single elements and a physical array. Results show that a source in the presence of a 10-dB higher-level interferer having exactly the same frequency content, as measured by a stationary receiver, is properly localized and that white-noise-constrained adaptive beamforming applied to the physical aperture data in combination with Doppler beamforming provides greater spatial resolution than physical-aperture-alone beamforming and significantly lower sidelobes than single element Doppler beamforming. A new broadband beamformer that adjusts for variations in vehicle velocity on sample by sample basis is demonstrated with data collected during a high-acceleration maneuver. The importance of including the cost of energy expenditure in determining optimal vehicle motion is demonstrated through simulation, further illustrating how vehicle characteristics are an integral part of the signal/array processing structure. [Work sponsored by the Office of Naval Research.]
Posterior inference of two closely spaced wave vectors for inference regarding the state of an acoustic target
Authors: Barros Abner C. , Anchieta David , Gendron Paul J.
Published: November 2016

A bistatic sonar arrangement is employed to infer the depth, speed, and range of an oncoming submerged acoustic target from a continuous wave transmission. Surface and direct interacting paths associated with closely spaced angles and frequencies from the returned acoustic wave fronts are resolved. A Gibbs sampler is employed to construct the posterior joint density of all parameters taking full advantage of the analytic tractability of the amplitude and phase of the wave fronts while the ordered wave vectors, their angles and frequencies are sampled numerically by two-dimensional quantile function. The inferred density of target depth, range, and speed is accomplished by constructing a numerical inverse-transformation of the forward propagation model. Simulations are used to demonstrate the potential of sub-Rayleigh resolution accuracy at less than -10dB received SNR with an 9 element vertical array.
Moving beyond side-looking imaging with synthetic aperture sonar
Authors: Prater James , King Jonathan
Published: November 2016

The desire to provide long-range high-resolution side-scanning sonar imagery necessitates the use of lower frequencies to overcome the relative high attenuation of high frequency sound waves and long apertures in order to achieve high resolution. This is typically accomplished through the application of synthetic apertures which collect wideband widebeam sonar data over time and post-process the data to produce high resolution imagery. While many of these systems were initially designed with high resolution long range imagery in mind, the wideband widebeam and temporal nature of the data provides the potential for signal processing and analysis to produce information about the imaged area beyond image intensity. This paper will discuss recent advances in SAS signal processing that exploit the wideband, widebeam, and temporal features of unbeamformed SAS data to extract additional information about the imaged area. Specifically, techniques that exploit aspect dependence (from widebeam data), frequency dependence (from wideband data), and temporal phenomena will be discussed.
Effect of low complexity adaptive beamforming on seafloor backscatter statistics
Authors: Lønmo Tor I. , Lyons Anthony
Published: November 2016

In contrast with the common delay-and-sum (DAS) beamformer, adaptive beamformers can be used to increase the resolution of acoustic measurement systems without sacrificing sidelobe levels. The non-linear nature of adaptive beamforming methods may cause changes to measured scattered amplitude distributions. For example, large differences in speckle statistics have been observed in some cases when using the adaptive minimum variance distortionless response (MVDR) beamformer in medical ultrasound, unless preventative measures were implemented. Low complexity adaptive (LCA) beamforming techniques have shown similar, but smaller, differences. Recently, experiments have been conducted in the Oslofjord, Norway, to determine whether low-complexity adaptive (LCA) beamforming techniques can improve the performance of bathymetric echosounders. When using LCA with these types of sonar systems, it is important to understand any changes to the backscatter statistics, as these changes may affect, e.g., seafloor classification methods. In this talk we will present comparisons between backscatter statistics estimated using a weighted delay-and-sum beamformer and those estimated using a low complexity adaptive beamformer. We will discuss any differences seen, possible mechanisms causing these differences and potential remedies. [Research supported by The Norwegian Research Council and Kongsberg Maritime. The first author is employed in Kongsberg Maritime.]
Physical oceanographic modeling of the inner Continental Shelf
Authors: Blumberg Alan F.
Published: November 2016

The nowcast and forecast of the marine environment in the shallow waters (0—20m depth) adjacent to the coast, the inner shelf, is important for the development of acoustic surveillance systems. These waters are among the most challenging marine environments in the world because they are subject to the combined geometrical constraints of irregular coastlines and highly variable bathymetry, and are forced both by a complex array of tidal, wind, and buoyancy forces on a broad range of space/time scales. Their proximity to the deeper waters flowing offshore introduces another array of complex sets of forcing. The resulting circulation patterns include both persistent and time-variable fronts, intense currents with strong spatial (offshore and/or vertical) dependence, waves, internally generated variability, large horizontal water mass contrasts, strong vertical stratification, and regions of intense turbulent mixing in both surface and bottom boundary layers. Frequently, the interplay between these multiple forcing mechanisms, geographic detail, stratification, and nonlinear dynamics, is significant, and this demands that a physically sophisticated coastal ocean model be capable of representing a comprehensive suite of dynamical processes. Drawing on the operational shallow water New York Harbor Observing and Prediction System (NYHOPS), we illustrate, by example, the breadth of dynamical processes that influence near coastal ocean circulation.
Stadia acoustic atmosphere and spectator experience: Quantifying crowd noise with architectural form
Authors: Valmont Elizabeth , Wilkinson Matthew , Thomas Ashwin
Published: November 2016

Very little reliable data exist on noise levels and associated crowd atmosphere in stadia. Discussed frequently in the media, several stadia are often portrayed as having the “best” and/or “noisiest” atmosphere. However, there is no accurate basis or measurement for these claims. This poses challenges when designing new stadiums with the intent to improve spectator experience. Architectural elements such as overhangs and vertical sound reflecting surfaces are well known to redirect acoustic energy and improve the overall noise level. However, the direct impact of these elements on crowd behavior and overall atmosphere is not well documented and limits quantifying drivers for new designs. Noise level data were gathered in this study from various stadia and correlated to architectural form using acoustic modeling. The paper details the data gathered at football games played at Autzen Stadium (partial roof overhang) and the Los Angeles Memorial Coliseum (open bowl architecture). The measured statistical data are analyzed and linked to the results of computer acoustic models of each stadium. Using the known dimensions of each stadium, the effect of architectural elements on the direct and reverberant noise level in the stands is presented.
Diffusion unwrapped, new testing that reveals real data
Authors: Lenz Richard L.
Published: November 2016

The concept of acoustic diffusion and devices that create diffuse properties has been around for well over 40 years. While there have been a number of test methods that have purported to show diffusion from these devices, the evidence of this is questionable at best. The author, along with others, has developed a new test method that can differentiate between specular and diffuse reflections as well as show many other characteristics desirable for acousticians and designers. This test method, being developed in coordination with ASTM, allows the user to see many different components of diffusion including polar responses, frequency response, attenuation, and phase characteristics, a key component of understanding a diffuse reflections. At the same time, the test method also shows the character of specular reflections, which difference is quite clear in the output data. The paper will also show how devices, from quadratic residue diffusers to geometric shapes, do not necessarily have the frequency response or diffuse reflections that we have assumed for many years. Many different examples will be presented as well as the different data outputs required to see how a diffuser actually performs.
Finite element sound field analysis for investigation on measurement mechanism of reverberation time in non-diffuse sound field
Authors: Tomiku Reiji , Otsuru Toru , Okamoto Noriko , Okuzono Takeshi , Kimura Youtarou
Published: November 2016

As well known, the reverberation time is essential to evaluate room acoustics; however, it is not so easy to predict in a practical room where the assumption of diffuse sound field is not satisfied. On the other hand, the numerical analyses based on the wave equation have been intensively used to explore many kinds of acoustic problems. In this study, 15 kinds of rooms with different absorption surfaces are analyzed by time domain finite element method. This study shows effectiveness of the analysis for investigation on measurement mechanism of the reverberation time of sound field in rooms where the assumption of diffuse sound field is not satisfied. To evaluate a sound field in a room for the measurement, the ratio of incident sound energy to a part of boundary in those to all boundary of a sound field in a room is calculated from results of the time domain finite element analysis. At first, the calculation method of the ratio of incident sound energy to a part of boundary in those to all boundary of a sound field in a room is described, and the ratios are calculated in the 15 kinds of rooms at each frequency. Finally, relationship among the ratios, mean absorption coefficients, reverberation times calculated from the results of TDFE analysis and those from Sabin’s formula is investigated.
Effect of the mass-spring resonance of a slab covered with carpets on the sound insulation performance
Authors: Yairi Motoki , Minemura Atsuo , Koga Takashi
Published: November 2016

It is well known that the overall sound insulation performance between two adjacent rooms in actual buildings is not so much increased even if a high spec wall is used for the partition because of several flanking sound transmission paths. In recent years, the phenomena that a slab covered with carpets increases the sound transmission through the floor have been found. This is caused by the resonance with the mass of the carpets and the spring of those underlying materials, and consequently the sound insulation performance significantly decreases in the mid-low frequency range. The resonance frequency can be shifted to higher frequencies using formed plastic sheets of higher stiffness for the underlying materials. Although this would usually be one of countermeasures to increase the overall sound insulation performance, it is not a fundamental solution for noise control engineering. In the present work, in order to control the mass-spring resonance itself, a method of focusing on permeability of the carpets is proposed. The resonance is expected to be damped with the flow resistance, which is caused by setting an appropriate permeability. It is theoretically investigated using a simple model, and an experimental validation is also carried out.
Acoustical considerations in shipping container architecture
Authors: Grant Anat , Waldeck Randy
Published: November 2016

The inherent strength, wide availability, and relatively low expense of intermodal freight containers have led to an increase in their popularity as framing elements for modular construction. In school expansion and renovation projects, modular construction can reliably achieve sustainability and energy efficiency targets, often with shorter construction schedules. Residential housing, offices, commercial buildings and other building types are also constructed using shipping containers. While shipping container architecture is a green alternative with many advantages, it can also present acoustical challenges in buildings occupied by people. Low ceiling heights often limit acoustical treatment possibilities, and acoustical test data on sound isolation is limited. Case studies and measurement data presented will include an elementary school with large divisible classrooms, a community education center, an after-school youth education and classical music program in an economically struggling Los Angeles community, and a multifamily apartment building in Berkeley, CA.
Central and western Pacific blue whale song and occurrence
Authors: Fisher-Pool Pollyanna I. , Oleson Erin , Širović Ana
Published: November 2016

Blue whale (Balenoptera musculus) occurrence in the central and western Pacific is not fully understood. However, passive acoustics offer an effective way to monitor remote sites. Blue whale songs are regionally distinct, and their stereotyped characteristics may be used to distinguish populations. Most blue whale song consists of multiple, pulsed and tonal units. However, song in the central and western Pacific consists of only simple tonal units. We investigated song variability of Hawaii, Wake Atoll, Palmyra, and Tinian in the Mariana Islands Archipelago, and highlight differences between blue whale songs amongst sites. Song calls of two different frequencies were recorded by High-frequency Acoustic Recording Packages. Detailed measures of call frequency were taken along the contours of tonal calls and patterning of song sequences was evaluated for recordings from the four locations during 2012 and 2013. The spatial and temporal occurrence of these patterns is discussed.
Stereotyped, repetitive gunshot call patterns produced by the North Pacific right whale, Eubalaena japonica
Authors: Crance Jessica , Berchok Catherine
Published: November 2016

The Marine Mammal Laboratory has deployed long-term passive acoustic recorders along the 50 m and 70 m isobaths throughout the Bering Sea since 2007. Instruments recorded at either 4 kHz on a ~7-11% duty cycle, or 8 kHz on a 30-45% duty cycle. In addition, directional sonobuoys were deployed during field surveys to allow real-time monitoring for large whale presence. During the 2010 survey, a stereotyped, repetitive gunshot call pattern was acoustically detected on sonobuoys. This same call pattern was then detected on two different long-term moored recorders in two separate years. Since then, six different stereotyped, repetitive patterns have been documented, three of which have been analyzed. Preliminary results show that each pattern has a minimum of 30 iterations repeated over several hours. Furthermore, in several cases, these patterns are repeated throughout the season, in consecutive years, and in one instance, in non-consecutive years. While male North Atlantic right whales produce long gunshot bouts similar to the reproductive advertisement known in other species, right whales are not known to produce any type of repeated stereotyped pattern. This represents the first study to document stereotyped repetitive gunshot patterning in right whales. [Work funded by the Bureau of Ocean Energy Management.]
Functional optical imaging from bat inferior colliculus using a micro-endoscope
Authors: Yashiro Hidetaka , Funabiki Kazuo , Simmons Andrea M. , Simmons James A. , Riquimaroux Hiroshi
Published: November 2016

We developed a confocal micro-endoscopic system that enables simultaneous recording of electrical neuronal responses—local field potentials (LFPs) and multi-unit activities, (MUA) — and fluorescence changes reflecting calcium activation derived from Oregon green dye. We recorded these responses from different depths of the inferior colliculus (IC) in two species of bats (Carollia perspicillata and Eptesicus fuscus) to tone bursts, noise bursts, and FM sweeps. Electrical responses were fast and registered the occurrence of sounds with submillisecond and millisecond precision. LFPs contained strong onset responses and weaker, extended oscillations that persisted for much of the sound’s duration. In contrast, calcium responses were slow, building up gradually over the course of 50-100 ms, and declined slowly following sound offset. Full horizontal-vertical video image scanning of the entire fiber optic bundle’s face was limited to 18.9 frames/s by the scanning mirror, but isolation and recording of successive individual horizontal scans, done by freezing the vertical scan, yielded 7,550 lines/s, or 132 microseconds for 1 line. Line-scanning revealed that the calcium responses indeed were slow, in the 50-100 ms range. They also were spatially diffuse, suggesting a distributed dendritic origin. [Work supported by JSPS, MEXT Japan, Shandong University, ONR, Capita Foundation.]
Ultra-high-frequency hearing in seals and sea lions in the context of other secondarily aquatic mammals
Authors: Reichmuth Colleen , Mulsow Jason , Sills Jillian M. , Southall Brandon L. , Cunningham Kane
Published: November 2016

The underwater hearing abilities of marine mammals near the upper frequency limit of hearing are poorly understood. While the maximum frequency of hearing is often identified following a sharp roll-off in sensitivity, it is apparent that many marine mammals can perceive high-amplitude tonal sounds above this frequency region. We recently measured underwater detection thresholds in quiet conditions in the 50-180 kHz range for one California sea lion, one spotted seal, and one harbor seal. Absolute sensitivity curves from these subjects exhibited two distinct slope regions at frequencies near the high-frequency hearing limit. The first region is characterized by an initial, rapid decrease in sensitivity with increasing frequency—i.e. a steep slope—while the second shows a much less rapid sensitivity decrease—i.e. a shallower slope. An additional masking study conducted with one of the seals suggested that the initial, rapid decrease in sensitivity is not due to cochlear constraints, as has been proposed, but rather due to constraints on the underlying bone-conduction mechanism. These results can be viewed in the context of the selective pressures influencing ultra-high-frequency hearing in other aquatic mammals, including those capable of specialized echolocation.
Control ultrasound beam by tissues in the head of finless porpoise acting as a tunable gradient index material
Authors: Zhang Yu , Song Zhongchang , Wei Chong , Au Whitlow W. , Cao Wenwu , Wang Xianyan
Published: November 2016

Porpoises are well known to emit directional ultrasound beams for detecting and tracking preys; however, how they produce and manipulate directional beams are challenging. Here, we investigated physical mechanism of ultrasound beam formation and control of finless porpoise (N. a. sunameri) by using an integrated scheme of computed tomography, tissue and field measurements, and numerical modeling. The results showed that complex acoustic structures in the porpoise’s forehead contributed to producing directional acoustic field. Furthermore, we demonstrated that the skull, air sacs, connective tissue, muscle, and melon constituted a gradient index (GRIN) structure whose density and sound velocity are positively correlated, and thus regulated the directional beam. The removal or compression deformation of the forehead tissues decentralizes energy and widens sound beam, indicating that the forehead tissues as a tunable natural GRIN material significantly impact beam patterns of the finless porpoise. The results might be valuable for understanding control mechanism of acoustic beam of other toothed whales.
Acoustic properties reconstruction of forehead tissues in an Indo-Pacific humpback dolphin (Sousa chinensis), with investigation on temperature effects on the species tissues sound velocity and beam
Authors: Song Zhongchang , Zhang Yu , Wei Chong , Berggren Per
Published: November 2016

Computed tomography (CT) imaging and ultrasound experimental measurements were used to reconstruct the acoustic properties (density, velocity, and impedance) of forehead tissues from a deceased Indo-Pacific humpback dolphin (Sousa chinensis). The nonlinear regression methods were used to demonstrate the relationships between the sound velocity and temperature in melon, muscle and connective tissue. The obtained nonlinear equations were then combined with the original CT scanning results and sound velocity distributions reconstructed at room temperature 25°C to reconstruct the dolphin head’s sound velocity distribution at temperature 37°C. The beam formation and beam properties between two temperatures 37°C and 25°C were then compared and discussed. The results could provide important information for understanding the species’ bioacoustic characteristics and the acoustic data can be used for investigation of biosonar beam formation of this species.
Say what? Hearing abilities and subsequent variability for a wild population of Beluga Whales (Delphinapterus leucas)
Authors: Mooney T. Aran , Castellote Manuel , Quakenbush Lori , Hobbs Roderick , Goertz Caroline , Gaglione Eric
Published: November 2016

Odontocetes use sound for vital biological functions and hearing is considered their primary sensory modality. To understand and predict noise impacts, we need to know natural hearing ability at the population-level. Yet we have no wild population-level hearing data for any cetacean. Here, we measured the audiograms (4-150 kHz) of wild beluga whales from 2012-2016 using auditory evoked potential methods. The goal of this work was to establish the mean audiogram and variance of wild beluga whales to define what this population hears. Audiograms were collected from 26 belugas during capture-release events in Bristol Bay, AK. In general, belugas showed excellent sensitivity (<60 dB) from 45 to 100 kHz and most (76%) heard up to at least 120 kHz. Hearing thresholds at lower frequencies 4-11 kHz tracked the low environmental noise levels (70 dB/Hz), suggesting that quiet habitats may allow substantial hearing sensitivity. Beluga audiograms show substantial (20-40 dB) variation but less than that of bottlenose dolphins suggesting possible differences between populations and the need for comparative data. Further, the hearing variability among belugas suggests multiple measures best describe the maximum sensitivity and population variance. These audiograms quadruple the data for beluga whales as a species and provide the beginning of population-level auditory data for a wild odontocete.
Ultrasonic vocalizations in laboratory mice
Authors: Burke Kali , Screven Laurel A. , Dent Micheal L.
Published: November 2016

Mice produce diverse ultrasonic vocalizations (USVs), which vary in spectrotemporal parameters including frequency, intensity, and duration. Although it is currently unclear whether mice are using these USVs for communication, researchers have attempted to parse USVs into categories based upon their spectrotemporal characteristics. There is recent evidence that shows that mice are producing context-specific vocalizations, but it is still unclear if USVs have any of the language-like characteristics that researchers would like to impose on them. The current literature clearly indicates a need for a comprehensive catalog of the USVs mice are producing in order to better understand if and how these animals are using their USVs for communication. Here, 20 male and 20 female mice were exposed to a same sex or opposite sex stimulus mouse for 1 hour and recorded immediately following separation for 3 min. All vocalizations were categorized based on their spectrotemporal characteristics. This experiment provides a catalog of the vocal repertoire of laboratory mice, adding to the existing knowledge of how they are using their USVs.
Investigating the occurrence of spinner dolphins around Maui Nui, Hawaii
Authors: McElligott Megan M. , Lammers Marc O. , Fisher-Pool Pollyanna
Published: November 2016

Spinner dolphins (Stenella longirostris) occur commonly along Hawaii’s sloping coastlines where they follow a daily behavioral routine of foraging offshore at night on vertically migrating mesopelagic and epipelagic prey and then return to shallower waters to rest during the day. Populations of spinner dolphins have been well documented off Hawaii island and Oahu, but much less so off the other islands. In the Maui Nui region (Maui, Molokai, Lanai, and Kahoolawe), spinner dolphins are sighted regularly, but little is known about their use of the nearshore habitat, which is characterized by much shallower bathymetry than Hawaii island and Oahu. As a result, spinner dolphins in Maui Nui offer a unique opportunity to examine the adaptability of the species to a habitat that would not be considered ideal for their life history needs. To better understand the habitat-use patterns of spinner dolphins in Maui Nui, bottom moored acoustic recorders are being used to examine spinner dolphin presence off west Maui and southeast Lanai. These data are compared to similar data previously obtained from a well-studied spinner dolphin population off west Oahu. Preliminary results from these analyses are presented in combination with data on habitat characteristics and anthropogenic impact.
Source levels and calling rates for humpback whale (Megaptera novaeangliae) non-song vocalizations in Glacier Bay Alaska
Authors: Fournet Michelle , Klinck Holger , Gabriele Christine
Published: November 2016

Marine resource managers in Glacier Bay National Park, Alaska, have been tasked with assessing the impact of vessel noise on marine mammal species. Humpback whales (Megaptera novaeangliae) are a highly vocal baleen whale that forage between spring and fall in Park waters. While calling rates and source levels for this species have been described on breeding grounds and migratory corridors, these fundamental acoustic parameters have not been thoroughly described on foraging grounds, and have never been empirically measured in the North Pacific. Using a three-element hydrophone array deployed in the Beardslee Island complex of Glacier Bay during the 2015 summer foraging season humpback whale “whup” and “growl” calls were localized and source levels were calculated. Array recordings were paired with shore based abundance estimates from the same period and calling rates (calls per whale per hour) were estimated. Known calling rates and source levels are essential for developing detection algorithms, masking metrics, and determining communication space on this historically important foraging ground.
Source levels of harbor seal underwater reproductive advertisement displays
Authors: Matthews Leanna P. , Womble Jamie , Gabriele Christine , Klinck Holger , Parks Susan
Published: November 2016

Harbor seals (Phoca vitulina), along with the majority of other phocid species, mate underwater. During the breeding season, male harbor seals set up underwater territories and use acoustic cues, known as roars, to defend these areas against intruder males and possibly to attract females. Vocalizations are low in frequency, predominately around 60-100 Hz, with some broadband components reaching up to 5 kHz, and range from 4-10 seconds in duration. Previously, source levels of vocalizations have only been estimated. Here we present a method for measuring vocalizations to estimate source levels of harbor seal roars. We used a three-element hydrophone array in Glacier Bay National Park to record harbor seal vocalizations during the breeding season (June—July 2015). Using the array, we localized individual vocalizing animals and calculated source levels of calls in the 40-500 Hz range. Knowledge of source levels for vocalizations of harbor seals is important for understanding how anthropogenic forces, such as noise from vessels, may impact the acoustic behavior and communication range of these animals.
Unsupervised clustering of toothed whale species from echolocation clicks
Authors: Trinh Yun , Lindeneau Scott , Ackerman Maya , Baumann-Pickering Simone , Roch Marie
Published: November 2016

Supervised learning of categories related to animal signals requires labeled data that are used to train a classifier. In areas where species assemblages are poorly understood, such labeled data are usually unavailable. We show that unsupervised learning techniques may be used to provide an initial assessment of an area. We demonstrate that clustering techniques can be used to group sets of echolocation clicks from different species into clusters that tend to contain a single species without any labeled examples. Results are presented on the 2015 Detection Classification Localization and Density Estimation (DCLDE) toothed-whale development dataset, which contains analyst labels for several species of odontocetes as well as an unknown category. Echolocation clicks were detected and grouped into acoustic encounters from which spectral and temporal features were extracted. We used a simplifying assumption of single species encounters and estimated distributions of features in each encounter. Dendrograms were constructed by average-linkage clustering using a symmetric Kullback-Leibler similarity metric. Different algorithms were used to partition the dendrogram, with partition quality estimated by the silhouette algorithm. Comparison of the best machine-generated partitioning with that produced by analysts yielded an adjusted Rand statistic of 0.66, demonstrating a good degree of concurrence.
Intraspecific variation in the swimbladder occurrence and possibility of acoustic discrimination of the dominant mesopelagic fish Diaphus garmaniioff western Kyushu, Japan
Authors: Yasuma Hiroki , Ohshima Shinya , Yasuda Tohya , Fukuwaka Masa-aki , Abe Koki
Published: November 2016

Diaphus garmanii (Family, Mictophidae) is the most abundant mesopelagic fish in the continental slope off western Kyushu. For the application of acoustic monitoring, we have observed the swimbladder morphology of this species to estimate the target strength (TS). In this session, we show the intraspecific variation in the occurrences and shapes of swimbladder in D. garmanii, and propose the acoustic discrimination of the swimbladder morphology for accuracy improvement in biomass estimates. Acoustic data and biological samples were collected in the summer of 2012 to 2014. Both of fishes with (30% in all samples) and without (70%) swimbladder were observed by the soft X-ray method, and frequencies of the swimbladder occurrence were significantly different between male and female fishes. Theoretical scattering models showed that the TS difference between 38 kHz and 70 kHz was the most preferable parameter to discriminate the swimbladder occurrence of D. garmaniiin field acoustic data. Field acoustic data analyses implied different patterns of vertical distribution between swimbladder and swimbladderless (male and female) fishes.
Modeling target strength of individual herring (Clupea harengus) at any aspect as a function of pressure and frequency
Authors: Pedersen Geir , Macalay Gavin J. , Peña Hector , Fässler Sascha M.
Published: November 2016

Fish target strength is primarily dependent on the physical dimensions of the fish, the acoustic frequency, and the orientation of the fish. In traditional vertically observing echosounder surveys, fish are insonified in the dorsal aspect with fairly limited tilt angle variation. In oblique-angled sonar surveys, however, fish may be insonified at other aspects. For herring, target strength is also depth dependent as they cannot refill the swimbladder at depth. Understanding the depth dependent target strength from several insonification angles is thus required for quantitative measurements with sonar. The dataset used in this study consists of seven herring, imaged using magnetic resonance imaging (MRI). The herring were placed in a pressure chamber inside the MRI, and subjected to different pressures corresponding to water depths of 0, 20, 40, and 60 m. Images were acquired of each specimen at each pressure. The swimbladders were segmented and 3D models of the swimbladders for each fish and pressure were constructed. These models were then used for computing the directivity pattern of the swimbladder at any angle as a function of frequency using the finite element method. Modeling results are also compared with measured dorsal and side aspect TS at different depths. The broadband backscattering (30-200 kHz) is evaluated for the potential for species and size discrimination and the effect including the fish body is discussed.
Acoustic scattering by tube-building worms (Polychaeta: Maldanidae) of the New England Mud Patch
Authors: Zeh Matthew C. , Wilson Preston S. , Lee Kevin M. , Ballard Megan S. , Dorgan Kelly M.
Published: November 2016

The acoustic effects of biological activity within shallow water ocean environments are not well understood, yet are of increasing importance in some sonar applications. These environments remain insufficiently characterized in part due to the presence of benthic organisms within and near the sediment and water-sediment interface. Among the most prevalent infauna found within muddy ocean sediments are tube-building worms (Polychaeta: Maldanidae). The presence of and bioturbation caused by these organisms can affect the acoustical properties of the ocean bottom sediment. These effects are being studied in experiments being conducted in the New England Mud Patch, on the continental shelf south of Martha’s Vinyard, MA. To begin to quantify these effects, laboratory acoustic scattering measurements of naturally collected worms and worm tubes were completed over a range of frequencies (50 kHz to 1 MHz) and incidence angles. Predictive models by Faran [J. Acoust. Soc. Am. 23, 405 (1951)] approximating the worms as elastic cylinders, and Doolittle [J. Acoust. Soc. Am. 39, 272 (1966)] approximating the worm tubes as cylindrical shells, were used to interpret the measured results. Measurements and model comparisons will be discussed along with implications relating to effective bulk sediment properties. [Work supported by ONR.]
Kidney stone pushing and trapping using focused ultrasound beams of different structure
Authors: Sapozhnikov Oleg A. , Nikolaeva Anastasia V. , Terzi Marina E. , Tsysar Sergey A. , Maxwell Adam D. , Cunitz Bryan W. , Bailey Michael R.
Published: November 2016

A technology to reposition kidney stones with radiation force was recently proposed by our team and already used to transcutaneously facilitate passage of small stones. While successful, the trial revealed a need for optimization of the ultrasound beam structure, frequency, and intensity to make it more effective. In the current work, the effect of the ultrasonic beam diameter vs. stone size using a quasi-Gaussian beam model was numerically investigated. Radiation force on a kidney stone was found to be strongest when the beam width was slightly wider than the stone diameter. This can be explained by more effective generation of shear waves inside the stone resulting from their effective coupling with the acoustic waves in liquid at the stone edges. In another study, the possibility of using vortex beams to trap the stones in the lateral direction was investigated. Both theoretical modeling and experiments were performed using two systems: a single-element transducer combined with a sector-shaped phase plate and a 12-element sector array. Human stones approximately 3-5 mm, as well as glass and styrofoam beads, were controllably translated along the surface transverse to the beam. [This work was supported by RBBR 14-02-00426, NIH NIDDK DK43881, DK104854, and DK092197, and NSBRI through NASA NCC 9-58.]
Robust servoing method for renal stones/tumors for the non-invasive ultrasound theragnostic system
Authors: Kayasuga Atsushi , Koizumi Norihiro , Tomita Kyohei , Nishiyama Yu , Tsukihara Hiroyuki , Fukuda Hiroyuki , Yoshinaka Kiyoshi , Azuma Takashi , Miyazaki Hideyo , Sugita Naohiko , Numata Kazushi , Honma Yukio , Matsumoto Yoichiro , Mitsuishi Mamoru
Published: November 2016

The main problem on HIFU (High Intensity Focused Ultrasound) therapy is the difficulty to locate HIFU focus precisely onto the focal lesion, which is located in the moving organ such as livers/kidneys, due to the deformation and rotation, which is caused by respiration. Furthermore, rib bones frequently block the acoustic path to the lesion. The acoustic shadow, which is generated by the rib bone, is observed in the ultrasound images and the lesion is hidden in the shadow. To cope with this problem, we have developed a novel method to track, follow, and monitor the lesion by utilizing the contour information of the organ, which incorporate the lesion under those difficult conditions. As for the tracking method, the contour of the organ, which is deformed and rotated in accordance with respiration, is extracted automatically in 2-D ultrasound images. The missing contour information in the acoustic shadow area is estimated and compensated by the surrounding contours, which are successfully extracted. To confirm the effectiveness of the proposed method, we compared the proposed method with the conventional method in terms of the tracking performance of the stone. As a result, we achieved the tracking performance (the average servo error is 2.3 mm) by the proposed method, while the average servo error is 3.57 mm by the conventional method. This shows the validity of our novel proposed method.
Combining burst wave lithotripsy and ultrasonic propulsion for enhanced kidney stone comminution
Authors: Zwaschka Theresa A. , Cunitz Bryan W. , Bailey Michael R. , Dunmire Barbrina , Maxwell Adam D.
Published: November 2016

Burst wave lithotripsy (BWL) and ultrasonic propulsion (UP) are two new focused ultrasound technologies for noninvasively treating kidney stones. BWL applies short, focused bursts of ultrasound to fracture stones. UP employs long-duration bursts of ultrasound to reposition stones and has been successfully tested on humans. We hypothesize that application of low-level UP can improve comminution by reorienting the stone and dislodging intervening fragments from the stone surface. Experiments were performed in a degassed water bath with a polyvinyl chloride tissue phantom mimicking a kidney calyx. An artificial calcite stone was placed in the phantom and aligned with the focus of a 330-kHz BWL transducer with a co-axial P4-2 imaging probe used for UP. Fragmentation size was compared between stones treated with a fixed 5-minute BWL exposure using 20-cycle bursts at 40 bursts/sec, with or without interleaved UP. The results showed improved fragmentation with the combined exposure, with 3 UP bursts/minute resulting in 45% of stone debris < 2mm versus 23% without UP (p = 0.011). Stones treated with UP alone did not fragment. These results suggest UP can improve stone fragmentation by BWL. [Work supported by NIH K01 DK104854 and P01 DK043881, and NSBRI through NASA NCC 9-58.]
A training phantom for ultrasound-guided boiling histotripsy therapy
Authors: Dunmire Barbrina , Kucewicz John C. , Kreider Wayne , Khokhlova Tanya D. , Schade George R. , Maxwell Adam D. , Sapozhnikov Oleg A. , Crum Larry A. , Khokhlova Vera A.
Published: November 2016

Boiling histotripsy (BH) uses millisecond-long focused ultrasound pulses with shocks to mechanically disrupt targeted tissue under real-time ultrasound monitoring. However, adipose tissue and ribs can interfere with BH therapy through aberration, absorption, and diffraction. Here we introduce a robust abdominal wall phantom that includes fat, muscle, and rib layers for demonstrating the use of BH and investigating the impact of anatomic structures on treatment success. The skin is a silicone sheet; the fat and muscle layers are poly-vinyl alcohol phantoms with irregular-shaped walls; the ribs are 3D-printed sections from a human model anatomically relevant to liver or kidney treatments. The target is a transparent alginate or polyacrylamide gel that allows visualization of the lesion. The pieces are assembled in a water-filled container providing coupling between layers and allowing components to be shifted in position relative to the transducer. A BH transducer (1.2 MHz, 12.5 cm focal length, f# = 1) containing an imaging probe in its central opening was used for initial phantom assessment. Preliminary results show that each layer impacts the beam in ways similar to observations from in vivo and ex vivo experiments. [Work supported by NSBRI through NASA NCC 9-58, NIH RO1EB007643, K01EB015745, and K01DK104854.]
Broad beam for more effective ultrasonic propulsion of kidney stones
Authors: Bailey Michael R. , Cunitz Bryan W. , Dunmire Barbrina , MacConaghy Brian , Wang Yak-Nam , Janssen Karmon , Brand Timothy C. , Corl Doug , Levy Oren , Sorensen Mathew D. , Harper Jonathan D. , Maxwell Adam D.
Published: November 2016

Ultrasonic propulsion uses focused bursts of ultrasound to generate radiation force to non-invasively reposition stones. Ultrasonic propulsion has been implemented on a C5-2 curvilinear array and shown to be safe and effective for expelling small stones and fragments in a human feasibility study. Here, we evaluated the efficacy of three different focal beam patterns in moving stones: 1) the existing approach exciting all 128 elements of the C5-2 transducer at 2 MHz, 2) exciting only 40 elements, and 3) implementing a separate single element transducer at 350 kHz. The capability of each method to lift clusters of 1-2 mm and 3-4 mm calcium oxalate stone fragments in a pipette was measured, filmed and compared by calculating the sum of the product of fragment area and distance moved for all fragments. For the same peak pressure, the alternative approaches (2 and 3) lifted greater stone mass than the original output. With 1-2 mm fragments, improvement with the three methods was 14% and 500%. For 3-4 mm, improvement was 45% and 178%. [Work supported by NIH NIDDK grants DK043881, DK107094, DK104854, and DK092197, the NSBRI through NASA NCC 9-58, and resources from the VA Puget Sound Health Care System.]
HIFU-induced cloud cavitation control for kidney stone treatment
Authors: Ikeda Teiichiro , Yoshizawa Shin , Matsumoto Yoichiro
Published: November 2016

The shock wave lithotripter uses an order of microsecond pulse durations and up to a 100 MPa pressure spike triggered at approximately 0.5—2 Hz to fragment kidney stones through mechanical mechanisms. One important mechanism is cavitation. We proposed an alternative type of lithotripsy method that maximizes cavitation activity to disintegrate kidney stones using high-intensity focused ultrasound (HIFU). We designed a two-frequency wave (cavitation control (C-C) waveform); a high-frequency ultrasound pulse to create a cavitation cloud, and a low-frequency pulse following the high-frequency pulse to force the cloud into collapse. High-speed photography showed cavitation collapse on a kidney stone and shock wave emission from the cloud. We also conducted in-vitro erosion tests of model and natural stones. For the model stones, the erosion rate of the C-C waveform showed a distinct advantage with the combined high- and low-frequency waves over either wave alone. Natural stones were eroded and most of the resulting fragments were less than 1 mm in diameter. The small fragments were small enough to pass through the urethra. The results demonstrate that, with the precise control of cavitation activity, focused ultrasound has the potential to be used to develop a less invasive and more controllable lithotripsy system.
Scattered shear wave contribution to acoustic radiation force on spheres in soft tissue
Authors: Treweek Benjamin C. , Ilinskii Yurii A. , Zabolotskaya Evgenia A. , Hamilton Mark F.
Published: November 2016

A theory for acoustic radiation force on a sphere in soft tissue was developed for arbitrary incident compressional wave fields [Ilinskii et al., Proc. Meet. Acoust. 19, 045004 (2013)]. This theory includes two contributions to the radiation force. The first depends only on the incident and scattered compressional waves, whereas the second depends on the scattered shear waves as well. Each contribution in turn has two parts, one due to direct integration of the time-averaged Piola-Kirchhoff stress tensor over the surface of the sphere, and the other due to the irrotational component of the body force on the sphere. While both parts are known analytically for the compressional waves, only the first part has been obtained analytically for the contribution involving shear waves. The irrotational portion associated with shear waves and its effect on the total radiation force is the subject of this presentation. The analysis is conducted via Helmholtz decomposition of the body force associated with shear waves and subsequent integration of the irrotational portion over the surface of the sphere. Simplifying analytical approximations based on numerical calculations are examined for various elastic properties of the sphere and soft tissue. [Work supported by the ARL:UT McKinney Fellowship in Acoustics.]
Evaluation of a model-based poroelastography algorithm for edema quantification
Authors: Pitre John J. , Weitzel William F. , Bull Joseph L.
Published: November 2016

A critical component of end stage renal disease treatment is optimal fluid management. Patients with reduced kidney function risk developing fluid overload, and many dialysis patients exceed recommended levels of fluid retention, leading to frequent clinical intervention and higher mortality. Despite this, current clinical standards of care rely on reactive semi-quantitative tests to grade fluid overload and peripheral edema. Poroelastography has been proposed as a quantitative means of estimating fluid overload in peripheral edema, but clinical studies have met limited success, in part because of measurement noise. We developed a new poroelastography method based on an inverse problem formulation to address the shortcomings of current methods. Our technique iteratively minimizes the error between ultrasound displacement measurements and the solution of a Biot poroelastic model. This formulation does not depend on noise-amplifying derivatives and ratios. We tested our algorithm in a simulation study using synthetic displacement data with Gaussian noise and speckle tracking measurements from simulated sonograms. Our algorithm accurately estimated the Poisson’s ratio at all noise levels tested. Reconstruction errors for all cases were less than 10% and outperformed traditional methods. Although our method required 4-12 hours to run, it is easily parallelized. Future work will focus on benchtop validation.