bluuebunny/crossref_metadata_2025 huggingface dataset:
Marine mammal distribution in the Gulf of Alaska from long-term passive acoustic monitoring
Authors: Rice Ally , Širović Ana , Trickey Jennifer , Hildebrand John , Baumann-Pickering Simone
Published: November 2019

The Gulf of Alaska is an important habitat for a diverse array of marine mammals. Conservation of these populations requires understanding how they utilize different habitats. Passive acoustic monitoring can be used to study marine mammal distributions because the unique call types produced by many species are well documented. Between 2011 and 2015, a total of 3793 days of recordings were collected from autonomous acoustic recorders at five locations broadly distributed around the continental shelf, slope, and offshore seamounts in the Gulf of Alaska. The spatial and temporal patterns of seven cetacean species were examined and differences in habitat use and behavior were compared. Inshore habitats featured higher detections of humpback (Megaptera novaeangliae) and gray (Eschrichtius robustus) whales, while blue (Balaenoptera musculus) and sperm (Physeter macrocephalus) whales were more commonly detected offshore. The presence of most species was seasonal, with peak calling in spring and summer for gray and sperm whales, and fall and winter for fin (B. physalus) and humpback whales. Call type distributions within a species differed spatially for fin and killer (Orcinus orca) whales, and seasonally for blue whales. Spatial differences may indicate prey preferences, while seasonal changes are likely related to behavioral shifts from feeding to mating.
Bowhead whale acoustic detection probability and spatial density of calls in ice-free and ice-covered Arctic waters
Authors: Jones Joshua M. , Hildebrand John , Thayre Bruce , Wiggins Sean M.
Published: November 2019

Estimation of Arctic marine mammal presence and acoustic density from passive acoustic monitoring is complicated by effects of the environment and noise levels on sound propagation and the detection of calls. We used acoustic modeling and detection simulations to estimate site-specific transmission loss for sounds produced by bowhead whales in the northeast Chukchi Sea at two sites, outer shelf and continental slope, with and without sea ice cover at various ocean noise levels. A time series of hourly acoustic detection probability was produced for the two recording sites between 2012 and 2013 from modeled transmission loss for daily sea ice state and hourly average noise levels. We applied the detection probability to recorded bowhead whale call detections to correct for effects of ice cover and noise level. Corrected acoustic presence suggests a decrease in detectable calls within a 40 km radius of the recording sites with arrival of open water while the uncorrected detections increase or change little. When sea ice state is constant, substantial variability in acoustic presence tracks closely with changing noise levels. These results highlight the importance of incorporating effects of the environment and changing noise levels when interpreting results of passive acoustic monitoring.
Ice floes' clashing as the source for acoustic ambient noise in the marginal ice zone of the Arctic Ocean
Authors: Chen Chi-Fang
Published: November 2019

The ambient noise in the marginal ice zone (MIZ) of the Arctic Ocean is generated by the clashing of ice floes on the sea surface, which is a feasible source mechanism based on the experimental evidence. A theoretical model of the MIZ ambient noise based on a floe/floe collision mechanism is presented. It predicts time series and spectra whose features are broadly consistent with those observed in the data. The noise spectral density in the frequency band from 50 Hz to 1 kHz varies with frequency as f- n, where the index n shows an average value approximately equal to 2. Over a period of five days or so, n was observed to vary between a low value of 1.0 and a high value of 3.0. This work was done with Professor Michael Buckingham when he was a visiting professor in MIT in 1986.
Benchmarking ocean acoustic models
Authors: Porter Michael B.
Published: November 2019

In this special session honoring the work by Buckingham, we review some of his early research from the 1980s where he developed analytic solutions to various benchmark problems. In particular, he developed elegant solutions for (1) the perfect wedge; (2) a penetrable wedge; and (3) a conical seamount. These were very valuable at the time in resolving errors in early parabolic equation models; they have continued to be important as computational models for fully three-dimensional environments have become more widely used.
Assessment of hepatic steatosis in humans using multivariable quantitative ultrasound
Authors: Han Aiguo , Zhang Yingzhen N. , Boehringer Andrew S. , Montes Vivian , Andre Michael P. , Erdman John W. , Loomba Rohit , Valasek Mark A. , Sirlin Claude B. , O'Brien, W. D.
Published: November 2019

The objective of soft-tissue quantitative ultrasound (QUS) is to improve diagnostic ultrasound imaging via quantitative outcomes. Over the past three or so decades, there have been an increasing number of QUS successes. In a UIUC-UCSD collaboration, nonalcoholic fatty liver disease (NAFLD) assessed from seven QUS biomarkers [AC, BSC, three Lizzi-Feleppa markers (slope, intercept, midband), two envelope parameters (k and mu)] derived from ultrasound RF data shows dependencies with the liver fat content in human subjects. 102 participants underwent QUS exams on the right liver lobe with an Acuson S3000 scanner (4C1 and 6C1HD transducers). Two multivariable models have been developed based on QUS biomarkers: (1) generalized linear regression model to predict hepatic PDFF using stepwise regression for biomarker selection and (2) regularized logistic regression model to classify normal (MRI-PDFF <5%, n = 26) versus NAFLD (MRI-PDFF ≥ 5%) using LASSO regularization for biomarker selection. Leave-one-out cross-validation was used for both models. The regression model selected the midband and k-parameter (R2 = 0.59, Spearman ρ = 0.84, and Pearson’s r = 0.77). The classifier model selected the midband and μ-parameter (AUC of 0.89). Multivariable QUS provides higher quantification and classification accuracy than univariate QUS approaches. [R01DK106419 and Siemens Healthineers.]
Deep learning approaches for quantitative analysis of ultrasound backscattered signals
Authors: Han Aiguo , Boehringer Andrew S. , Montes Vivian , Andre Michael P. , Erdman John W. , Loomba Rohit , Valasek Mark A. , Sirlin Claude B. , O'Brien, W. D.
Published: November 2019

Quantitative ultrasound (QUS) aims to improve diagnostic ultrasound imaging by extracting objective tissue parameters from backscattered signals. Deep learning can facilitate this process because of its ability to extract high-level information from the raw data. We have demonstrated that deep learning approaches applied to backscattered signals can accurately quantify liver fat noninvasively. We will discuss three deep learning approaches herein: (1) a one-dimensional convolutional neural network (1-D-CNN) for uncalibrated radiofrequency (RF) data; (2) a two-dimensional CNN (2-D-CNN) for uncalibrated spectrograms; and (3) a 2-D-CNN for calibrated spectrograms. Approaches (1) and (2) do not require system calibration with a physical phantom, whereas Approach (3) obtains calibrated spectrograms with a physical phantom. Each approach is evaluated using three datasets that contain ultrasound RF data acquired from the right liver lobe and contemporaneous MRI-PDFF (reference standard) in participants with and without nonalcoholic fatty liver disease: 204 scanned by a Siemens S2000 ultrasound scanner (4C1), 70 scanned by a Siemens S3000 scanner (4C1 and/or 6C1HD), and 104 scanned by both the S3000 and a GE Logiq e9 scanner (C1-6). We will discuss the advantages and disadvantages of each approach evaluated using data acquired across multiple ultrasound scanner platforms. [Supported by R01DK106419.]
Evaluation of reference-free and model-free spectral-based quantitative ultrasound in vivo
Authors: Oelze Michael L. , Nguyen Trong N.
Published: November 2019

Two limitations of spectral-based quantitative ultrasound techniques for characterizing tissues in vivo are: (1) the need for one or more separate calibration measurements per scanning session and (2) lack of well-defined models of scattering. In the first case, the requirement to take a reference scan for each setting used in a clinical procedure can disrupt the busy clinical workflow. In the second case, the choice of models to interpret backscatter coefficient data may not utilize all of the information available in the backscatter coefficient spectrum. To address these issues, we have explored the use of machine learning techniques in phantoms and in vivo without requiring a model and in some cases without requiring a reference. A convolutional neural network (CNN) was utilized that took in the raw RF ultrasonic backscattered data from the livers of rabbits (N = 57) maintained on a high fat diet and classifier was constructed from the CNN. The same scanner settings were used on all rabbits and no reference signal was used with the CNN. The hypothesis was that the CNN could differentiate between tissue signal and system signal. The accuracies of the reference-free and model-free approaches were compared to traditional quantitative ultrasound techniques.
Quantitative ultrasound in obstetrics and perinatal care
Authors: Rosado-Mendez Ivan M. , Torres Abel , Castañeda-Martinez Laura , Torres-Arvizu Francisco , Carlson Lindsey , Palmeri Mark L. , Zagzebski James , Rivaz Hassan , Ikonomidou Chrysanthy , Feltovich Helen , Hall Timothy J.
Published: November 2019

This talk will present recent results from our multi-institutional effort to advance the application of Quantitative Ultrasound in obstetrics and in perinatal care. In the field of obstetrics, we are investigating the use of shear wave elasticity imaging (SWEI) to predict the risk of preterm birth based on assessing the viscoelastic properties of the uterine cervix. Longitudinal studies in non-human primates (NHP) and humans showed a similar rate of decrease of the shear wave speed, SWS (1.6% and 1.5%/% gestational age, respectively), validating the animal model and indicating the value of SWS change as a biomarker for cervical softening. We are currently optimizing the analysis of shear wave dispersion to assess changes in viscosity. In the field of perinatal care, results from a pilot study in NHP neonates suggest that the effective size of diffuse scatterers can be used as a biomarker for thalamic apoptosis induced by long exposures to anesthesia. We are currently investigating the use of coherent scattering features to increase the sensitivity and specificity to neuroapoptosis and to improve attenuation and backscatter coefficient estimations in complex tissues such as the cervix and the neonate brain. [Acknowledgments: All protocols have been IRB- and/or IACUC-approved, and are HIPAA compliant. Equipment loan and technical support from Siemens Healthcare. Funded by: NIH Grant Nos. T32CA009206, F31HD082911, R01HD072077, UL1TR000427, P51OD011106, and R01HD083001; NSERC Grant No. RGPIN-2015-04136; and UNAM-PAPIIT IA104518 and IN107916.
Quantitative ultrasound to better evaluate heterogeneous tumor response to therapy
Authors: Bridal Lori , Coron Alain , Gâteau Jérôme
Published: November 2019

Heterogenity of tumor structure and function (e.g., stromal density, vascularization, and oxygen distribution) can influence local cellular proliferation and therapeutic resistance. Emerging ultrasound imaging techniques can map parameters related to these features but such approaches are not yet in standard clinical practice. The goal of our work is to develop robust protocols to provide more complete information during therapy by quantitatively mapping and interpreting tumor heterogeneity using emerging ultrasonic techniques. Within murine tumor models Shear Wave Elastography (SWE), Contrast-Enhanced Ultrasound (CEUS) and Quantitative Ultrasound (QUS) techniques have been applied with clinical imaging systems to compare changes observed during anti-angiogenic and cytotoxic therapy as compared to controls. In a Lewis Lung Carcinoma model, mice receiving an anti-angiogenic therapy had the highest levels of necrosis and fibrosis and presented the highest number of correlations between quantitative parameters related to microvascular function and tumor structure. This indirectly demonstrates, for this tumor-type, that quantitative parameters measured with clinical imaging systems can help differentiate tumor therapeutic responses. Promising results with ultrasound localization microscopy and photoacoustics will also be reviewed because of the important new information they offer. Finally, the path towards integration of these quantitative ultrasound techniques in clinical practice will be discussed.
Quantitative cardiac blood flow imaging with high frame rate ultrasound
Authors: Hasegawa Hideyuki , Nagaoka Ryo
Published: November 2019

The measurement of blood flow is important for evaluation of cardiac function. Ultrasonic color Doppler imaging is one of the most frequently used methods for the measurement of cardiac blood flow. However, the Doppler method provides only the axial velocity components in the direction of ultrasound propagation. To overcome such a problem, the vector flow mapping method (VFM), which estimates 2-D blood flow velocity by applying the theory of fluid dynamics to the axial velocity field obtained by the color Doppler method. However, the frame rate is limited to less than 30 frames per second (fps), and better temporal resolution is preferable for evaluation of the rapid temporal change in cardiac blood flow. In the present study, echoes from blood cells were visualized by high frame rate ultrasound imaging at a frame rate of 6250 fps. Recently, echo particle image velocimetry (e-PIV) was developed for observation of cardiac blood flow. This method requires intravenous injection of ultrasonic contrast agents. On the other hand, the proposed method does not require contrast agents. Also, echoes from blood cells are visualized at a very high frame rate, and thus, blood flow velocity vectors can be estimated quantitatively by applying motion estimator to visualized echoes.
Intrinsic cardiovascular strain and wave imaging using rapid frame rate imaging
Authors: Konofagou Elisa
Published: November 2019

Cardiovascular disease currently claims more lives each year in both men and women than the next two most deadly diseases combined, i.e., cancer and chronic lower respiratory disease. Among the cardiovascular diseases, coronary artery disease (CAD) is by far the most deadly accounting for 44% of cardiovascular-related deaths and causing approximately 1 of every 6 deaths in the United States in 2019. Approximately every 34 s, 1 American has a coronary event, and approximately every 1 min 23 s, an American will die of one. Clinical observations also show that the formation, expansion, and rupture phases of a vessel due to pathologies such as aneurysms and atherosclerotic plaques are each associated with changes in arterial stiffness. Pulse Wave Velocity (PWV) is often used as a biomarker, but imaging of pulse waves and characterizing the propagation has been essential in staging vascular disease. In this paper, ultrasound-based methodologies at high frame rates will be presented that provide information on both the mechanical and electrical properties of the myocardium as well as mechanical properties of the vascular wall through intrinsic phenomena and rapid wave propagation in order to better image the onset and progression of the aforementioned diseases.
Real-time imaging of brain displacement during FUS neuromodulation in rodents in vivo
Authors: Kugelman Tara , Burgess Mark T. , Konofagou Elisa
Published: November 2019

Focused ultrasound (FUS) is capable of modulating the central and peripheral nervous system. Temperature increase, cavitation, and acoustic radiation force have been proposed as potential mechanisms. Thus, tissue displacement imaging during FUS modulation is critical to understanding its physical mechanism. A cranial window was formed to perform imaging during FUS neuromodulation in C57BL/6 mice. FUS sonications were performed with a 4 MHz single-element transducer with a focal volume 0.2 × 0.9 mm (Sonic Concepts, WA), an applied tone burst of 0.5 ms and peak positive pressures varying from 1.9 to 6.7 MPa. Real-time channel data using plane wave sequences were acquired with an 18 MHz linear array (Vermon, France) and axial displacements throughout the entire brain were estimated using 1D cross-correlation (9λ window, 99% overlap) at 1 kHz frame rate. Downward displacements were only detected during FUS within the focal region. During modulation, the cumulative displacement ranged from 0.021 ± 0.017 μm (n = 3) at 3.1 MPa to 0.24 ± 0.004 μm at 6.7 MPa (n = 3). Displacement decreased post-FUS and returned to null within 1–2 ms. Unlike in a preliminary phantom study, no shear waves were detected. Real-time displacement imaging could thus provide effective targeting and monitoring as well as unveil the mechanism during FUS modulation.
On an improvement of the sound separation ratio according to exciter attachment method of flat TV
Authors: Park Hyung Woo , Lee SungTae , Park Kwanho , Bae Myungjin
Published: November 2019

In the case of a flat-screen TV, the position of the sound was properly configured by reproducing the sound directly from the left and right sides of the screen. However, focusing on the image quality and design elements, it was hidden above. With several experimental factors, we were able to reproduce a lot of sound from the bottom speaker. This is disadvantageous in that it cannot hear the reproduced sound directly, hears mainly the reflected waves of the space below the space where the information display device is located, and hears different sounds depending on the characteristics of the reflection surface. In this study, we introduce a technique to make a sound with a direct screen that complements these shortcomings. In a large-sized flat-screen TV, the sound drives an exciter attached to the rear, proposing a way to improve forward beam forming depending on the attachment method. Compared to the conventional exciter attachment method, the improved direction ratio is improved by 22% and the voice separation ratio of the multi-channel according to the horizontal view distance is improved. Therefore, this method will contribute well to the use of a big size flat display speaker in multi-channel entertainment applications.
Ultrasonic inspection of lithium-ion batteries to determine state of charge, state of health, and battery safety
Authors: McGee Tyler , Archibald Erik , Ezekoye Ofodike A. , Haberman Michael R.
Published: November 2019

Accurately estimating state of charge (SOC), state of health (SOH), and other metrics of battery safety remains a challenge for lithium ion batteries outside the laboratory, where one may use techniques such as X-ray diffraction, electrochemical impedance spectroscopy, or neutron imaging. Existing in situ methods to estimate SOC and SOH employ voltage monitoring or Coulomb-counting. Unfortunately, these methods remain inaccurate because they assume a battery capacity or voltage per discharge, while capacity and voltage are known to vary with C-rate and cycle age. The present work explores the viability of interpreting SOC, SOH, and safety metrics by monitoring and interpreting ultrasonic signals propagating through a battery as it is cycled between charged and discharged states in various environmental conditions. Of specific interest are cases where a battery enters dangerous operating conditions which lead to the formation of gases within the battery as well as increases in internal temperature, pressure, and battery volume. To investigate this regime, the received ultrasonic signals are monitored over the course of charging and discharging cycles and analyzed in the time and frequency domains in an effort to provide an in situ means to estimate SOC, SOH and battery safety metrics.
Enabling rapid charging lithium metal-based rechargeable batteries through suppression of dendrite growth and ion depletion in the electrolyte via surface acoustic wave-driven mixing
Authors: Huang An , Liu Haodong , Manor Ofer , Liu Ping , Friend James
Published: November 2019

Lithium metal is an attractive material for use as anodes in batteries due to its high energy density. However, it is unstable during recharging, with non-uniform Li deposition that leads to porosity, dendrites, rechargeable lithium metal batteries (LMB) have been unrealistic for fifty years with serious safety problems. Over this time, research on chemistry modifications have produced modest improvements, but none that have justified considering LMB over lithium-ion batteries in rechargeable applications. Nonuniform Li deposition during charging occurs due to a Li ion depletion layer adjacent to the anode, especially at high charge rates. By including a small surface acoustic wave device (SAW) into the LMB that produces intense acoustic waves in the electrolyte, rapid submicron boundary layer mixing flow may be generated during charging. This flow largely eliminates the Li ion depletion layer, and because the SAW device is small, solid state, and requires only 10 mW h/cm2 during battery charging, there is a realistic possibility of incorporating this technology into current batteries under consideration for an electric vehicle, consumer device, and medical applications. The elimination of the ion depletion layer furthermore allows high-rate charging, as we will demonstrate in our electrochemistry and morphological results. The underlying physics will be explained using a closed-form model formed from intermediate asymptotics, and will show the crucial impact of the Peclet number in avoiding the ion depletion layer.
Building and maintaining an active research laboratory with undergraduates
Authors: Kloepper Laura
Published: November 2019

Immersing undergraduates in research is important for the advancement of students into graduate school and the workforce. Mentoring undergraduates, however, often requires a different approach than mentoring graduate students. In this talk, I will share practical tips on how I have built and maintained an active, funded research laboratory at a primarily undergraduate institution. Specifically, I will explain my strategies for attracting and retaining students, my tiered mentoring approach for first-year through senior students, and the benefits I have received from these mentoring relationships.
Here, go read these papers: An approach to engage undergraduate and graduate research students with literature
Authors: Ryan Teresa J. , Hall Melissa A.
Published: November 2019

One of the key tasks of a research mentor is to foster the skill of independent inquiry. Central to effective independent inquiry is the ability of students to extract meaningful value from the topical research literature. For several years, students applying to be part of the acoustics and vibrations lab at East Carolina University have been required to summarize a select research paper as part of the interview process. That task provides a valuable barometer to evaluate prospective research students. It also has provided the nucleus for an evolving system to mentor students through the process of learning how to effectively interact with topical literature. This system has been used both to onboard new research students and to support directed research and independent study courses. This talk will present the approach—implemented in an asynchronous and largely self-paced manner with the university learning management system—and some key case study examples.
High precision measurements of acoustic impedance: Applications to the voice and respiratory tract, musical instruments and their players
Authors: Hanna Noel N. , Smith John , Wolfe Joe
Published: November 2019

The acoustic impedance spectrum of the vocal tract and trachea is important in speech and singing. The operation of musical wind instruments depends on the impedance spectra of their bores, and sometimes also on the impedance spectra of the player’s vocal tract. Here, we describe two measurement techniques. The three microphone technique, calibrated with three non-resonant loads, achieves large dynamic range measurements of the frequencies, magnitudes, and bandwidths of resonant duct maxima and minima. The impedance minima are particularly important in flute family instruments and in the voice, where resonances correspond to minima at the lips. These measurements can also be used to estimate the duct geometry and acoustic properties at the distant end, which may be otherwise inaccessible. The capillary or current source technique has been used to measure impedance maxima inside the mouths of wind players during performance, e.g., where saxophonists tune their tracts to the note played, and for “ecological” measurements during speech and singing that give estimates of resonant frequencies that are rather better than those from formant estimation at high pitch. This technique has recently been updated to run in real-time and made available as open source software, with modest equipment requirements.
Speckle pattern interferometric studies of guitar top plate materials
Authors: Thulin Spencer , Tabbutt Sam , Hoffman Kurt
Published: November 2019

We present experimental measurements of the resonances of guitar top plates using a speckle pattern interferometer. The studies include sanded spruce starting materials of different grades and finished commercial guitars. The spruce top plates consist of three different wood grades reflecting the quality of the wood grain. The normal mode frequencies and patterns are measured without sides to be consistent with the tap tones a Luthier would use to determine the quality of the top plate. We will discuss the ways in which the wood grade changes the frequency and distribution of normal mode frequencies due to variations in the grains of the raw wood. We will also compare these results to measurements on commercial guitar top plates.
Traffic noise in street-level hotel rooms
Authors: Taubitz Sarah
Published: November 2019

A one-story butler-style building was renovated to become a trendy 6 guest-room hotel, at the corner of a city intersection. Road noise infiltrates the rooms, some guests have publicly complained. Various measurements were made and will be presented, including: Noise Reduction (NR); Reverberation Time (RT); short- and long-duration overall and frequency-band LAeq; AOITC; and leakage path investigations. Several noise treatments will be presented.
Doppler's shift on aircraft noise propagation in modern aircraft noise prediction tools
Authors: Wang Yiming , Li Kai Ming
Published: November 2019

Doppler’s effect is an important factor in the prediction of the noise levels caused by en-route aircrafts. This study is focused on the influence of Doppler’s effect on the propagation of aircraft noise. The received sound pressure can be increased/decreased by Doppler’s effect depending on the relative location of the sound source and receiver. At the same time, the spectral shape of the noise is shifted by this effect which has an impact on the measured A-weighted noise levels. This influence is largely due to the fact that A-weighted correction factors of mid-frequency range are much larger than that those in the low-frequency regime. In this paper, a series of field trial was used to study the propagation effect of noise generated by a propeller-driven aircraft. Aviation Environment Design Tool (AEDT), a widely accepted noise prediction model of aircraft noise, is used to compare with the predictions according to a ray-based numerical model. The inclusion of Doppler’s effect in the noise prediction model has shown to have a better agreement with the field measurement results. The influence of Doppler’s effect on the noise-power-distance (NPD) curves of several different aircrafts is also presented. [Work sponsored by ASCENT, FAA Center of Excellence for Alternative Jet Fuels and Environment.]
What our prehistoric ancestors can teach us about echoing soundscapes that is relevant to modern noise studies
Authors: Waller Steven J.
Published: November 2019

Results of archaeoacoustic studies are applied to outdoor entertainment noise investigations. When considering impacts of noise in modern urban environments, it is well to consider the evidence left by our ancestors regarding the influence of reflective sound surfaces, as well as cultural perceptions of the sounds themselves. Acoustic research into the placement of global prehistoric rock art has revealed that our ancestors selectively chose echoing environments to produce cave paintings and canyon petroglyphs. Furthermore, those images depicted often match descriptions of echo spirits contained in ancient echo myths from around the world. The cultural perception of echoes was that these “extra” sounds were considered mysterious answers from sacred beings worthy of worship—the same phenomena that today are understood as sound wave reflections and considered annoying. Implications for modern noise investigations are discussed. Measure not just noise source amplitude, but consider also the effect of reflective urban structures to multiply, distort and overlap noises, sometimes acting as whisper galleries to cause sound to carry far down “urban canyons.” Also, relative to perception, a given dB level can affect different listeners in different ways, e.g., certain music perceived as entertaining to some may be perceived as unpleasantly disturbing to others.
Detecting instances of focused crowd involvement at recreational events
Authors: Cook Mylan R. , Todd Eric , Woolworth David S. , Gee Kent L. , Transtrum Mark K.
Published: November 2019

This paper describes the development of an automated classification system for detecting the amount of focused effort present in crowd cheering. The purpose of this classification system is for situations where crowds are to be rewarded for not just the loudness of cheering, but for a concentrated effort, such as in Mardi Gras parades to attract bead throws or during critical moments in sports matches. It is therefore essential to separate non-crowd noise, general crowd noise, and focused crowd cheering efforts from one another. The importance of various features—both spectral and low-level audio processing features—are investigated. Data from both sporting events and parades are used for comparison of noise from different venues. This research builds upon previous clustering analyses of crowd noise from collegiate basketball games, using hierarchical clustering with both supervised and unsupervised machine learning approaches.
Inverse design of acoustic devices: From flat lenses without negative refraction to acoustic cloaks based on scattering cancellation
Authors: Sanchez-Dehesa Jose , Sanchis Lorenzo , Andersen Peter R. , Cutanda Heniquez Vicente
Published: November 2019

Inverse design is currently applied to obtain unusual acoustical devices based on ordered and non-ordered scatterers. Recently, flat and lenticular acoustic lenses, de-multiplexors, directional sound sources and acoustic cloaks have been designed using a variety of optimization methods like genetic algorithms, simulated annealing and shape or topology optimizations among others. For example, feasible one-directional cloaks were first designed in two- and three-dimensions using high symmetry objects like cylinders [Appl. Phys. Lett. 99, 074102 (2011)] and toroidal scatterers [Phys. Rev. Lett. 110, 124301 (2013)], respectively. Recently, an extraordinary simple one-directional acoustic cloak has been reported using a technique that combines the method of fundamental solutions with arbitrary shape scatterers [Sci. Rep. 8, 12924 (2018)]. Here, we report a further improvement of the method by combining the Boundary Element Method (BEM) with shape optimization to obtain quasi-omnidirectional cloaks in two-dimensions. The shapes of the scatterers are optimized for the cloaking of the whole setup with waves impinging on the stealth object (a cylinder) from many different directions. An important feature of the method is the possibility of including visco-thermal acoustic losses in the optimization process [J. Sound Vib. 447, 120–136 (2019)].
Multi-holographic metamaterials: The concept, artificially intelligent designs, and new applications in acoustics
Authors: Urzhumov Yaroslav
Published: November 2019

Acoustic holographic metamaterials present a powerful new platform for manipulating acoustic wave fields in fluids and solids. Furthering their development, we introduce a new concept of multi-holographic metamaterials (MHM)—complex media storing multiple volumetric holograms. Such media lack any distributed electromechanical components, yet offer dynamic functionality using only a few electronic components. This novel engineering paradigm shifts device fabrication cost from hardware to computation, presenting the designer with an NP-hard problem of resolving the complex relationship between structure and physical properties. Focused on airborne ultrasonic metamaterials, we treat them as a free-form composite of a fluid and solid(s). This unlocks a huge number of structural degrees of freedom, compared to the standard treatment of metamaterials as periodic arrays of geometrically similar unit cells. While analytical methods for finding all optima of an analytical function are scarce and largely impractical (Groebner basis computation being a notable example), we turn to machine learning methodologies to design MHMs efficiently. We show that unsupervised machine learning, a basic form of Artificial Intelligence, can completely replace human input into the design of MHMs. Experimental demonstrations include airborne ultrasonic metamaterials for coherent beamforming, with applications ranging from directive speakers to contactless manipulation of objects.
An integrated framework for the design of aeroacoustic metamaterials
Authors: Iemma Umberto , Göransson Peter
Published: November 2019

This paper deals with the development of an integrated framework for the development of acoustic metamaterials tailored to aeroacoustic applications. Indeed, the contributions available in the literature targeted are still limited (although constantly increasing) with respect to the gigantic amount of works on standard acoustic metamaterials. The research is driven by the urgent need to substantially reduce the noise produced by the civil aviation to guarantee the sustainable evolution of the system in a constantly growing market. The target reductions required to mitigate the impact on population will be achieved only through the introduction of breakthrough technologies. The present research aims at the complete disclosure of the acoustic metamaterials potential to contribute to this target. The approach starts from the formulation of the fundamental equations governing the propagation of an acoustic disturbance within a generic metacontinuum operating in the presence of a background flow. The model is coupled with an original homogenization scheme, to identify, through numerical optimization, the basic properties of a periodic structure matching the target metacontinuum response. Preliminary numerical results are obtained using dedicated finite and boundary element methods.
Exploring the Lombard Effect in first language Japanese speakers of English
Authors: Kawase Saya , Smith Michael L. , Wright Richard
Published: November 2019

Speakers adjust pronunciations in noise to make communication more effective. This phenomenon, known as the Lombard Effect after Etienne Lombard who first described it in 1911, is characterized by increased intensity, elongation of vowels, emphasis on stress syllables, increased pitch range, and changes to the vowel space (see Brum and Zollinger, 2011). Because the Lombard Effect interacts with linguistic factors (e.g., Wassink et al., 2006 and Patel and Schell, 2008) we hypothesize that a speaker’s native language will interact with the Lombard Effect and that second language speakers of English will carryover these effects. To test this prediction, we recorded native speakers of North American English and L1 Japanese speakers of L2 English participating in a modified map task to illicit natural communication between the speakers and the experimenter, in two conditions: noisy and quiet (presented over headphones). Measurements of vowel duration, vowel quality, and intensity were extracted from key words representing monosyllabic and trochaic words with six vowel qualities: /i ɪ a æ u ʊ/. Preliminary results indicate some language specific differences, but also unexpectedly that vowel space is more compressed in the Lombard condition than in quiet, which has connections to findings of Zhao and Jurafsky (2009) for Mandarin.
Data-driven IoT-platform for optimizing variable acoustics in multifunctional performance spaces
Authors: Sadeghnia Golam Reza
Published: November 2019

Increasingly more venues are used as multifunctional performance spaces, where a variety of musical genres and spoken word is performed. Churches are turned into public meeting houses, museums are used for concerts and lectures, and concertgoers have an increasing awareness of the acoustical qualities of performance spaces. The problem with multifunctional performance spaces is that different types of performances require different low-frequency acoustical profiles, and changes in the interior of these spaces, audience density and distribution have a significant impact on the acoustic response of a space. Various solutions for variable acoustics have been proposed with predefined fixed settings. However, as of today there is no integrated solution for configuring and validating variable acoustic treatment. We propose a solution based on wireless, fully configurable acoustic panels with variable absorption in the 63 Hz to 8 kHz bands. The mounting method has integrated sensors that communicate with a central model for measuring, calibrating and configuring an assembly of acoustic panels for a certain usage. With several panels mounted on adequate surface areas of a performance space, the system allows parametric control of acoustic treatment to offer optimized variable acoustics. Applications for this type of technology range from educational environments, multipurpose auditoria, and cinemas, to parametric acoustics for mixed reality scenarios.
Exploring kelp forest soundscapes using ad hoc frequency-based metrics
Authors: Butler Jack , Jaffe Jules , Parnell Ed , Širović Ana
Published: November 2019

The kelp forests off the southern California coast are alive with sound, yet their soundscapes remain poorly studied. The kelp forest soundscapes of two sites off La Jolla, CA were surveyed: one within a marine protected area, the other outside of the protected area. Four frequency-based metrics were created to explore how the sounds of the kelp forest vary throughout the day and through the seasons. Two of the metrics tracked frequencies associated with putative fish choruses (60–130 Hz and 300–500 Hz), one metric tracked the long-duration humming of plainfin midshipmen (tonal calls with a fundamental frequency at 85–95 Hz, and harmonics at 175–185 and 265–275 Hz), and the final metric tracked snapping shrimp snaps (2.5–7.5 kHz). The two metrics that tracked the fish choruses exhibited both diel and seasonal periodicity, with strong spectral peaks in the late spring and early summer coinciding with the presence of the choruses. Similar to these two metrics, the metric that tracked the humming of the midshipmen exhibited nightly spectral peaks in the late spring and early summer during their spawning season. The metric that tracked snapping shrimp exhibited strong spectral peaks during dawn and dusk hours yet had little seasonal variability.
GPU technology in the high frame rate ultrasound imaging era
Authors: Yiu Billy Y. , Chee Adrian J. , Yu Alfred C.
Published: November 2019

As a rapidly maturing class of many-core parallel computing hardware, graphical processing unit (GPU) has enjoyed a surge of interest in the medical ultrasound community in the past decade. In particular, the software-level programmability of GPUs has significantly lowered the entry barrier for ultrasound imaging researchers (who might not be parallel computing specialists) to pursue fast realization of novel imaging algorithms that have known theoretical potential but have yet to demonstrate their real-time feasibility. This presentation shall highlight how GPUs have emerged as a new computing workhorse in realizing various ultrasound imaging innovations. Of particular note is the enabling role that GPUs have played in fostering practical pursuit of high-frame-rate ultrasound (HiFRUS) imaging innovations that are based on direct processing of pre-beamformed radiofrequency (RF) data acquired from individual array elements. Using the state-of-art GPU technology, it is readily possible to achieve >1,000 fps HiFRUS beamforming throughput. GPU can also play a pivotal role in facilitating fast realization of computationally intensive HiFRUS algorithms, such as adaptive beamforming, color-encoded flow speckle imaging, and eigen-processing. The real-time performance of these GPU computing kernels will be discussed, and their practical implementation on software-oriented open-platform research systems will be presented.
Short-lag spatial coherence imaging with multi-line transmission to improve needle visibility in ultrasound images
Authors: Matrone Giulia , Lediju Bell Muyinatu A. , Gonzalez Eduardo , Ramalli Alessandro
Published: November 2019

Ultrasound Short Lag Spatial Coherence (SLSC) imaging exploits the spatial coherence (SC) of backscattered echoes to suppress acoustic clutter and to significantly improve image contrast, particularly in difficult-to-image patients. Multi-line transmission (MLT) imaging simultaneously transmits multiple beams to increase frame rates. We hypothesize that the combination of SLSC and MLT has the potential to enhance detectability of coherent structures within a tissue background. Sector images of a 14G biopsy needle inserted within ex vivo bovine meat were acquired after implementing single-line transmission (SLT) and MLT with 4, 6, 8 and 16 simultaneous beams. The SLSC algorithm was applied to the acquired data. Results show that MLT SLSC images have a visibly darker background than SLT SLSC images, which is caused by the rapid decorrelation of the SC at short lags with MLT. This decorrelation is caused by inter-beam crosstalk interferences and can be leveraged to enhance the coherence of highly reflective targets within a tissue background, causing an increase in needle contrast from about 25 dB with SLT to ∼44 dB with 16-MLT. These results support our hypothesis that the decorrelation caused by crosstalk improves visualization of highly coherent targets within tissue, with promising applications to biopsy needle localization.
Singing in the city: Trade-offs between signal salience and vocal performance in the presence of anthropogenic noise
Authors: Phillips Jennifer N. , Luther David , Derryberry Elizabeth
Published: November 2019

Many animals use acoustic signals to communicate. Signals specifically used to compete for or select a mate are under sexual selection. Selection therefore favors signaling traits that indicate competitive ability or mate quality. For example, performance of signaling traits that are costly to produce, such as those that are physically limited by the animal's size or coordination are more likely to convey honest information about the sender. Selection also favors signaling traits that maximize the transmission of this information in a given environment. For example, other sounds in the environment (the soundscape) can reduce the ability of individuals to detect or decode information in the signal. However, individuals may not always be able to maximize both performance and transmission of a signal. This leads to two critical questions—when faced with this trade-off, which aspect of the signal do senders maximize and how does this decision affect communication? I address these questions using a well-studied sexual signal—bird song—in anthropogenic soundscapes, which are evolutionarily recent selective environments. Here, I tested whether vocal performance functions in male-male competition in White-crowned Sparrows (Zonotrichia leucophrys), and how assessment of performance varies across different urban and rural soundscapes in San Francisco and Point Reyes, California. I also investigate how soundscapes go beyond individual behavior and affect survival of these populations.
Effects of rail vibrations on humans and mitigation solutions
Authors: Born Alexander C.
Published: November 2019

The impact of rail vibrations on humans is becoming a more prominent issue as buildings are being built closer and closer to rail lines due to limited development space. I will cover this impact along with solutions to prevent it.
Co-speech movement behavior in conversational turn-taking
Authors: Danner Samantha G. , Krivokapic Jelena , Byrd Dani
Published: November 2019

Co-speech movements like those of the hands, head and face are thought to be important to the seamless turn-taking that is a hallmark of conversational interaction. We hypothesize that the spatiotemporal characteristics of co-speech movements vary as a function of turn-taking context (e.g., interruptions, felicitous floor exchanges) and/or a participant’s conversational role (speaker/listener). Though there is very little prior research in this area, work on manual gestures has shown that the rate of gesture (gestural density) varies contextually. In this study, we examine gestural density of head and brow gestures of interacting speakers considering two factors: (1) type of conversational turns (compared to non-turn-adjacent speech) and (2) participant conversational role. We analyze four dyads participating in a naturalistic conversational speech task recorded with magnetometer movement-tracking of lips, maxilla, brows, jaw, and head. Linear mixed effect models tested whether gestural density of head-nods and brow-raises differs among turn type and/or conversational role. Significant effects and interactions for both brow and head movement indicate that co-speech gestural density is jointly modulated by turn type and role. We find an examination of co-speech movement to be a fertile field of exploration in the study of interactional prosody and discourse. [Work supported by NIH.]
Custom-Made Daily Routine Increases the Number of Steps Taken by Frail Older Adults
Authors: Ando Suguru , Higuchi Yumi , Kitagawa Tomomi , Murakami Tatsunori , Todo Emiko
Published: November 2019

This study examined whether the number of steps taken by frail older adults increased after two types of interventions (custom-made daily routine [CDR] vs. exercise) were conducted over 12 weeks. The participants were 36 frail older adults aged 84.5 ± 6.0 years who attended a day-care center. They were assigned to one of three groups: CDR (n = 13), home-based exercise (HE,n = 10), or control (CON,n = 13). A wrist-worn accelerometer was used to measure their step count in 24 hr for 6 days. The CDR group demonstrated a daily step count change of approximately 25%, which was significantly higher than that of the CON group (effect size [r] = .51,p = .040). There were no significant changes in the HE group. Thus, a CDR might be useful for increasing the number of steps in frail older adults.