bluuebunny/crossref_metadata_2025 huggingface dataset:
A new rating method for low-frequency impact noise
Authors: Skoug Ryan L.
Published: November 2019

Residents, building owners, architects and acoustic consultants are rightly concerned about footfall noise transmission through multi-family building floor/ceiling assemblies. By code, most projects in the USA are required to meet a minimum design rating of IIC 50; AIIC 45 if field tested. However, no matter how high the rating, residents in wood frame buildings often complain that low-frequency, or “thudding” footfall noise is a problem. Unfortunately, the IIC rating system does not evaluate impact noise at frequencies below 100 Hz. In this paper, we show that footfall noise is present at audible frequencies below 100 Hz, how this footfall noise can be replicated more objectively using ball drops or a tapping machine, and how measured impact noise might be used to develop a single number rating for low-frequency impact noise insulation of field tested floor/ceiling assemblies. The findings presented are not meant to be taken as final results, but rather a summary of progress made to-date for work that is under-development.
Information and suggestions for new mentors of research students
Authors: Dowling David R.
Published: November 2019

Identifying, attracting, motivating, and mentoring research students (mentees) are challenging tasks for junior faculty members and research scientists (mentors) who are typically also concerned with obtaining research funding, teaching well, and/or impressing colleagues. This presentation covers three general concepts for effective mentoring that have worked well for the author during nearly 30 years as a faculty member. (1) Let the truth be your only story. In addition to its moral clarity, this policy increases research efficiency and tends to be respected even when it’s unpopular. (2) Know who students are and what motivates them. Students are academic free agents with a variety of motivations who commonly bring human-interaction complexities to the mentor-mentee relationship. (3) Engage in student-centric advising. The mentor acts as an academic parent who (typically) determines the mentee’s first research steps, guides their subsequent development, and then supports them through their final degree. Descriptions, explanations, and examples related to these three concepts are presented. Although this content is primarily derived from the author’s academic experience advising graduate students, it may be useful in industry and government settings as well, and for mentors and mentees alike, whenever extended duration advising requires the development of a mentor-mentee relationship.
Comparing two approaches for outdoor ambient noise level measurements
Authors: Jones Zachary T. , Cook Mylan R. , Gee Kent L. , Transtrum Mark K. , Calton Matthew F. , James Michael M.
Published: November 2019

In ambient community noise measurements, two possible setups involve an elevated microphone or on the ground [ANSI 12.9-2005/Part 2]. This study compares the elevated and ground-based microphone measurement approaches, particularly for low-frequency wind noise contamination. Wind speed measurements were made at heights of 0.15 m and 1.5 m, and one-third octave spectral histories were recorded simultaneously at the ground and at 1.5 m. The acoustical measurements both used Larson Davis 831C sound level meters, but the elevated microphone setup employed a commercial outdoor windscreen, whereas the ground-based setup utilized a larger reticulated foam windscreen. The measurements, each with durations between 1.5 and 4 h, were repeated at several locations. The results show the ground plate setup is preferable for obtaining wideband spectral measurements for two reasons. First, the wind speed is lower near the ground. Second, for the same wind speed, the larger windscreen yields superior wind noise rejection. These observations are quantified and discussed, and connected to expanding the available noise database for a machine-learning model for soundscape prediction. [Work supported by a U.S. Army SBIR.]
Electrical substation noise control case studies and lessons learned
Authors: Keefe Joseph A.
Published: November 2019

Electrical substation noise comprises noise from electrical transformers (magnetostrictive hum and cooling fan noise) as well as HVAC systems associated with buildings and enclosures. These noise sources are necessary to serve the public need for power distribution. Site sound emissions should have minimal acoustical impact on receptors and in most cases are required to comply with regulatory limits pertaining to noise. A few case studies are presented that address challenging noise control situations for electrical transformers and other electrical substation noise sources, including the acoustical consultant’s role in the project, identification of regulatory limits and project criteria, acoustical analysis, approach to noise control recommendations, and lessons learned.
Acoustic nonreciprocal topological insulators
Authors: Liang Bin , Zhu Xuefeng , Cheng Jianchun , Ding Yujiang , Peng Yugui , Zhu Yifan
Published: November 2019

Nonreciprocal acoustic systems, in which the reciprocity obeyed by wave motion in conventional propagation media, offer the possibility to achieve asymmetric transmission and contain rich physics. The emergence of “acoustic rectifier” for the first time realized both theoretically and experimentally the non-reciprocal wave phenomenon that the acoustic energy flows only in one direction and thereby created a “one-way street” for sound. With the extraordinary capability to redefining the common paradigm of wave propagation, non-reciprocal materials are promising for the development of acoustic topological insulator. Later it is proven that giant acoustic nonreciprocity can be provided by an angular-momentum-biased circulator. However, the practical implementation remains challenging due to other difficulties such as nonsynchronous rotation and flow instabilities. The experimental realization of an acoustic Chern insulator is recently reported based on a mechanism that uses an angular-momentum-biased resonator array to break reciprocity, which reduces the required rotation speed by leveraging high Q-factor resonance. Experimental results show that such systems support one-way nonreciprocal transport of sound at its edges, in direct analogy to electronic quantum Hall insulator. The realization of acoustic nonreciprocal insulators opens up opportunities for exploring unique observable topological phases and developing nonreciprocal devices in acoustics, with potential application in diverse scenarios.
Topological edge transport and one-way field localization in acoustic systems
Authors: Zhu Xue-Feng
Published: November 2019

Recently, the fields of valley acoustics and nonreciprocal acoustics have become hotspots due to the potentials in developing various acoustic devices. In this presentation, we first introduce the concept of programmable routing of topological sound transport through boundary engineering, which reveals the inherent relation between the field symmetries of valley states and structural symmetries of sonic crystals. Three functional devices are exemplified, which are single-crystal-based topological delay-line filter, delay-line switcher and beam splitter. Our results clearly demonstrate the high-transmission valley transport along the folded boundaries, where reflection or scattering is prohibited at the sharp bending or corners due to topological protection. Then we show an analog of stimulated adiabatic passage in acoustic systems, where the cavities and time-varying couplings mimic discrete states and radiation pulses, respectively. With appropriate arrangements of coupling actions, acoustic waves can be efficiently transferred from the initial excited cavity to the target cavity in the forward direction, immune to the intermediate dark cavity. Whereas for the backward propagation, the acoustic energy is perfectly localized in the intermediate dark cavity and completely dissipated. We analytically, numerically, and experimentally demonstrate such unidirectional sound localization and unveil the essential role of zero-eigenvalue eigenstates in the adiabatic passage process.
Global effect of locally applied active damping illustrated by laser vibrometry
Authors: Ryaboy Vyacheslav
Published: November 2019

Theoretical analysis suggests that decentralized active vibration damping implementing skyhook control (or advanced versions thereof), while applied locally, reduces vibration level over the whole structure by introducing modal damping. That was, however, never directly confirmed experimentally. Laser vibrometry, measuring vibration in multiple points in quick succession and referencing it to the excitation force, provides this opportunity. This paper reports theoretical considerations and experimental results illustrating reduction of total kinetic energy of all-steel optical breadboard by two active dampers. It had been shown (S. Elliott et al.) that the effect of collocated decentralized vibration control is limited by two phenomena: instability and “pinning.” These issues are analyzed by direct measurement of kinetic energy for a range of active control gains. Optimal gains minimizing kinetic energy with sufficient stability margin are demonstrated and discussed.
Degree of vocal fold adduction affects listener perception of simulated laryngeal vocal tremor
Authors: Lester-Smith Rosemary A. , Story Brad H.
Published: November 2019

Laryngeal vocal tremor (VT) is a neurogenic voice disorder characterized by modulation of the fundamental frequency (fo) and intensity. The primary medical treatment for VT is laryngeal botulinum toxin injections, which result in temporarily reduced speaker- and listener-perceived VT severity. These injections also cause temporary breathiness, which is conventionally considered an adverse effect of the treatment. However, previous studies using a computational model of VT revealed that listeners perceived modulated voices as less “shaky” when the vocal quality was breathy, even when the extent of fo modulation was the same. The purpose of the current study is to assess the effect of breathiness on listener perception of VT across a range of modulation extents. A kinematic model of the vocal folds and wave-reflection model of the vocal tract were used to simulate VT with degrees of vocal fold adduction representing a spectrum of normal to breathy voice and with fo modulation extents ranging from 0%–10%. Normal hearing listeners will be presented with pairs of stimuli differing by degree of vocal fold adduction and will be asked to identify which vowel is “shakier.” The findings of this study could inform selection of treatment targets and candidates for behavioral therapy for VT.
The development of tone and intonation in Mandarin-speaking children—A pilot study
Authors: Yang Jie , Davis Barbara
Published: November 2019

Mandarin is a tone language in which fundamental frequency (F0) is used to contrast lexical meaning and to convey intonation information. When tone and intonation interact, speakers maintain the shape of the F0 contour for word meaning contrasts but manipulate the magnitude of F0 change to meet intonation requirements. This pilot study provided a new perspective on tone acquisition by exploring phonetic characteristics of tone in different intonation contexts by Mandarin children who have acquired phonological contrasts. Three-, five- and eight-year-old monolingual Mandarin-speaking children and adults participated in this pilot study. Production of monosyllabic Tone 2 (rising F0) and Tone 4 (falling F0) words in isolation and in carrier sentences with interrogative (rising) and declarative (falling) intonation were elicited. Magnitude of F0 change, duration and intensity of the target words were acoustically measured and analyzed. Results suggested (1) a physiological basis of phonatory production where Tone 2 and falling intonation were produced more accurately; (2) lexical first strategy in the youngest children who prioritize tone accuracy over intonation accuracy; and (3) usage of developmentally appropriate and controllable acoustic cues first (e.g., Duration).
Effects of prosody on acquisition of anticipatory coarticulation by Italian-speaking children
Authors: Bonaventura Patrizia , Collins Maura , DiRenzo Magda
Published: November 2019

This study investigates patterns of acquisition of anticipatory lingual coarticulation by children in Typical Development (TD) and with Speech Sound Disorders (SSD): contradictory data have detected different degrees of coarticulation in children versus adults. This research brings evidence from Italian-speaking children, and analyzes also effects of prosody on development of coarticulation. 2 Italian-speaking SSD and 2 TD, 6-8 years, pronounced disyllabic non-words of different stress structure ([pV’tV] and [pVtV’]), upon elicitation by 2 adults. Both CV and V-V anticipatory coarticulation were measured, by (1) locus equations on CV sequences, indicative of regular patterns of stop-consonant interaction with different vowels; (2) trajectories (extent and duration) and slope index (extent/duration) of V-V F2 transitions. Preliminary results based on locus equations scatterplot and regression lines slope coefficients, show similar degree of coarticulation in TD and SSD versus adults in unstressed CV condition, but higher slope values (greater anticipatory coarticulation) in SSD, in stressed CV position. These findings suggest that (a) similar patterns of emergence of anticipatory coarticulation appear in TD versus SSD versus adults, in unstressed condition, with a slightly greater degree of coarticulation in SSD versus TD (b) prosodic factors seem to affect acquisition of coarticulation in SSD.
Real time 3-D ultrasound diagnostic imaging system including 3-D adaptive beamforming processing
Authors: Stergiopoulos Stergios
Published: November 2019

This paper describes the analog front end module and the computing architecture components of a fully digital real-time 3-D ultrasound system. The computing architecture is designed to allow for an efficient implementation of a 3-D adaptive beamformer that has the capability to improve the angular image resolution of a planar array by approximately four times. The complex 3-D beamforming structure is decomposed into two steps of line array beamformers and this kind of decomposition process for the 3-D beamformer allows for its efficient implementation into the highly parallelized multi-processor based computing architecture for real time 3-D ultrasound imaging applications providing 20 volumes per second at a full opening angle of 80 deg (azimuth and elevation). The main objective of this paper is to describe the details of the system processing requirements and design consideration for the computing architecture and provide the experimental results showing that the proposed implementation can achieve the targeted frame rate. An easy to use user interface in combination with a decision-support process provides the possibility for a rapid and automated diagnosis of internal injuries like bleeding or facilitates image guided surgery.
Ed Sullivan: Mentor, scientist, colleague, and friend
Authors: Edelson Geoffrey S.
Published: November 2019

I had the great fortune of meeting Ed Sullivan in 1989 when he was the Manager of Basic Research at the Naval Undersea Warfare Center and, to his dismay, was spending almost all of his time managing rather than researching. Ed hired me as a part-time student associate to analyze and implement passive synthetic aperture sonar, the core of our collaborative efforts for over twenty years and the technical focus of this presentation. Conversations with Ed, whether technical or not, were intellectually stimulating, fun, or mostly a combination of the two. Importantly though and through Ed’s confident and unique lens, he provided me – and many of you – with insights into highly relevant areas such as matched field and model based signal processing, music, history, and physics!
Integral equations for scattering from a rough ocean bottom
Authors: Tang Dajun
Published: November 2019

The motivation for this work is to develop a method in order to assess the impact of bottom roughness on transmission loss and reverberation in the mid-frequency range (1–10 kHz). A set of integral equations of the second kind is developed which yields formally exact solutions for sound scattering by a one-dimensional rough interface separating two homogeneous fluid half- spaces. The second kind equations have better convergence properties as compared to the first kind equations and are better suited for iteration methods, which is needed in dealing with scattering from very long rough interfaces at small grazing angles. The current work optimizes the equations to avoid the issue of hyper-singularity. Numerical examples are shown to demonstrate the validity of the method. The well-established but less well known forward- and backward iteration schemed developed by Kapp and Brown for sea surface scattering is extended to the seafloor scenario. It is found that the iteration method is highly effective, and one, or at most two iterations, are enough to yield accurate results for cases involving typical roughness encountered in a natural seafloor. This paves the way for modeling seafloor scattering over large distances and waveguides. [Work supported by ONR Ocean Acoustics.]
Variability of Doppler shift in the ocean bottom reverberation data from the East Sea of Korea
Authors: Jung Young Cheol , Kim Seongil , Lee Keunhwa , Seong Woojae
Published: November 2019

Sea trials measuring the ocean bottom reverberation using an active towed array sensor (ATAS) equipped with triplet receiver array were conducted in the East Sea of Korea during August, 2015. The continuous-wave waveforms with center frequency 3 kHz and pulse lengths of 0.1, 0.3, and 1 s are used as source signals, respectively. Ship velocity was between 4 and 5 knots and the water depth varies from 500 to 1250 m. Also, sound speed profiles were obtained by expendable bathythermographs (XBTs) during the ship maneuvering, where the depths of minimum sound speed appeared between 208 and 306 m. From the measurement results, we observed variability and spreading of reverberation Doppler shifts, which depends on the bottom bathymetry, platform motion, source depth, and receiver array depth. In particular, significant asymmetry of the Doppler spectrum occurred at the depths of the source and receiver below 120 m. The instantaneous frequency Doppler of reverberation signal in each beam direction provides information on the bathymetry and scattering characteristics of the bottom. This frequency shift is traced in time and analyzed.
Passive acoustic inversion with virtual head waves
Authors: Li Jie , Gerstoft Peter , Siderius Martin , Fan Jun
Published: November 2019

A passive acoustic inversion method with virtual head waves extracted from ocean surface noise is presented. The noise is assumed to be coming from the sea-surface due to wind and waves and a vertical array is used to produce beamformed time-series. Cross-correlating a beam steered downward with one steered upward at the same angle produces virtual head waves with periodic peaks in the time-series but only for the beams steered at the seabed critical angle. The virtual head wave has the same phase speed as the real head wave, but travel time is offset, thus virtual. It has been attributed to the cross-correlation between head waves and head waves or head waves and perfect reflections. With two of the virtual head wave travel times and the critical angle, an inverse method is developed to extract the water depth, water column and seabed sound speeds as well as the array depth. The theory is developed for the expected travel times and this provides the basis for the inversion methodology. Both the theoretical framework and the inversion method will be presented along with illustrating examples.
Standard for acoustic metadata for passive acoustic monitoring
Authors: Baumann-Pickering Simone , Roch Marie A.
Published: November 2019

Passive acoustic monitoring often relies on data collected with various instrumentation, by multiple research groups in different locations, under diverse conditions, and with a variety of data analysis methods. To make the output comparable and to preserve data for long time-series analysis, metadata needs to be reported in a standardized way. This will enable broader metadata studies and the sharing of data in repositories, which will allow for cross fertilization of analyses and hence cost savings for new projects. The Acoustical Society of America Working Group S3-SC1-WG7 “Acoustic Metadata for Passive Acoustic Monitoring” is in the process of defining this standard. We are building upon schemata developed for the metadata database software “Tethys” [Roch et al., Ecol. Inf. 31, 122–126 (2016)]. Instrument deployments and on- or off-effort detections of acoustic signals were defined within this manuscript. The current deployment schema is being implemented in the National Center for Environmental Information Passive Acoustic Monitoring Archive. We have expanded the vocabulary to include mobile platforms, vector sensors, localizations, and calibrations. Exemplary scenarios were developed to test the comprehensiveness of the current standard definitions for these frameworks. We also consider extensibility, making sure that the standard is flexible enough to support new ideas.
Explosions recorded underwater offshore of southern California
Authors: Wiggins Sean M. , Krumpel Anna , Rafter Macey , Dorman LeRoy , Hildebrand John , Baumann-Pickering Simone
Published: November 2019

Sounds from explosions can travel long distances underwater due to their high sound pressure levels, potentially impacting marine life. We evaluated and characterized explosion sounds from underwater recordings to better understand the signature of these sounds, how they propagate in the ocean, and how they may be differentiated for different source types. A controlled experiment using small (∼2 g) “seal bomb” sources at various source-receiver ranges was conducted offshore of southern California to characterize their waveform signature, including bubble pulses due to subsurface explosions ∼4 m depth and peak source level estimate of 234 dB re 1 µPa at 1 m. Opportunistic recordings of missile explosions during military exercises offshore of southern California were made by autonomous hydrophone recorders ∼1000 m deep. The military explosions were presumably at or near the sea surface and did not exhibit bubble pulses, allowing them to be differentiated from fisheries seal bomb sources for manual or automatic signal classification in underwater acoustic recordings.
Evaluation of cochlear compression in a bottlenose dolphin: A forward-masking evoked-potential study
Authors: Popov Vladimir , Supin Alexander , Nechaev Dmitry , Sysueva Evgeniya
Published: November 2019

Compressive nonlinearity allows to analyze sounds within a very wide level range. It is a property of the “active” cochlear mechanism based on electromotility of outer hair cells. It was not known is this mechanism capable to function at high frequencies accessible for hearing of odontocetes. Nonlinearity can be measured assuming that on-frequency masking is subjected to compression whereas the low-frequency masking is not. To eliminate confounding effects (lateral suppression and off-frequency listening), forward masking of near-threshold test stimuli must be used. In a bottlenose dolphin, on- and low-frequency forward masking of near-threshold test stimuli was measured in conjunction with the auditory evoked potential method. Test stimuli were short pips of 90 kHz frequency, the maskers were pips of 90 kHz (on-frequency), 76, 64, or 54 kHz (0.25, 0.5, and 0.75 oct below the test). Masker-to-signal delays varied from 2 to 20 ms. With increasing the delay from 5 to 20 ms, the on-frequency masker level at threshold (MLT) increased by 27 dB, whereas the low-frequency MLT increased by 4.5 dB. The compression was evaluated as 1:6. [Work supported by Russian Foundation for Basic research, Grant 18-04-00088 to VP.]
Variability of the geoacoustic properties of infauna-bearing marine sediments
Authors: Lee Kevin M. , Ballard Megan S. , Dorgan Kelly M. , Venegas Gabriel R. , McNeese Andrew R. , Wilson Preston S.
Published: November 2019

Infauna influence sediment physical parameters, such as porosity, grain size, and pore fluid properties, through bioturbation and other biological processes. To investigate the effects of the resulting sediment inhomogeneity, in situ measurements of compressional and shear wave propagation were acquired in Petit Bois Pass, west of Dauphin Island, Alabama, USA. After completion of the acoustic measurements, diver core samples were collected from between the sources and receivers to characterize the physical properties of the seabed along the acoustic propagation paths. The collected sediments were analyzed for infauna biomass and geotechnical properties to support acoustic propagation modeling. The acoustic data are analyzed in the context of infaunal functional groups, which are based on acoustically significant traits such as body type (hard/soft and large/small) and infaunal activity (sediment mixing or tube building). While existing sediment acoustics models do not explicitly account for effects of biology, they do allow for parameterization of various physical properties, which can be modified by the presence of biological organisms and bioturbation. Results from the in situ acoustic measurements and core analysis will be compared with such models to gain insight into the acoustical effects of infauna. [Work supported by ONR.]
Combined passive acoustic and video monitoring of coral reefs to better understand reef soundscapes and multi-species interactions
Authors: Freeman Lauren , Freeman Simon , Gader Paul , Fick Ronald , Kroeger Nicholas , Thode Aaron , Thilges Kayla , Van Uffelen Lora J. , Rowley Sonia , Schindall Jeffrey , Johnson Alexis
Published: November 2019

A detailed understanding of ecological soundscapes provides a window into ecosystem state that might otherwise go undetected. Rather than consider acoustic emissions of a particular species, a top down ecosystem acoustics point of view gives potentially valuable insights to reef ecosystem function. Simultaneous passive acoustic and video data were collected from coral reefs off the Kona Coast of Hawaii in January 2019 during a soundscape experiment. Frequent interactions between fish species as well as collective behaviors are identified and tracked by applying computer vision to video data. Comparison relating video data to acoustic data allows assessment of the same behaviors as simultaneously reflected in directional passive acoustic data. Collective consideration of acoustics and video offers insight into acoustic signatures of particular soniferous communities and behaviors amongst and between reef species. Machine learning applications match patterns between fish trajectories in videos and the sound field as received by a directional antenna. The relative level of biological activity and presence or absence of particular behaviors provides key data in the effort to understand coral reef ecosystem state.
Transfer learning for ultrasound tongue contour extraction with different domains
Authors: Mozaffari M. Hamed , Sankoff David , Lee Won-Sook
Published: November 2019

Due to the low-contrast characteristic and noisy nature of ultrasound images, it might require expertise for non-expert users to recognize tongue gestures. In the last few years, deep learning methods have been used for delineating and tracking tongue dorsum. Deep convolutional neural networks (DCNNs), which have shown to be successful in medical image analysis tasks, are typically weak for the same task on different domains. In many cases, DCNNs trained on data acquired with one ultrasound device, do not perform well on data of varying ultrasound device or acquisition protocol. Domain adaptation is an alternative solution for this difficulty by transferring the weights from the model trained on a large annotated legacy dataset to a new model for adapting on another different dataset using fine-tuning. In this study, we addressed the problem of domain adaptation on ultrasound datasets for tongue contour extraction. We trained a U-net network, and then with several surrogate scenarios, some parts of the trained network were fine-tuned on another dataset as the domain-adapted networks. We repeat scenarios from target to source domains to find a balance point for knowledge transfer from source to target and vice versa. The performance of new fine-tuned networks was evaluated on the same task with images from different domains. Our experimental revealed that a deep model can be used effectively for different domains using a knowledge balance point between those models.
Sonogenetics: Non-invasive cellular manipulation using ultrasound
Authors: Vasan Aditya , Magaram Uri , Lee-Kubli Corinne , Tufail Yusuf , Mendoza Jose , Ramirez Marc , Weiss Connor , Chalasani Sreekanth , Friend James
Published: November 2019

Optogenetics has been an important tool used in manipulating different cell types, understanding various diseases and has recently been studied as an alternative to electrical manipulation techniques used in a clinical setting. It has the drawback of being an invasive cellular manipulation technique, which limits its applications. Ultrasound is an alternative, non-invasive approach to precisely control cellular function. We propose the development of ultrasound transducers to selectively manipulate cells that have been transfected with mechanically sensitive proteins, in a new technique termed “Sonogenetics.” This study describes recent results in single crystal piezoelectric transducer design and characterization, results from in-vitro studies to identify mechanosensitive proteins, and an in-vivo study where miniature head mounted transducers were used to stimulate the ventral tegmental area of the mouse in order to trigger dopamine release. Ultrasound based stimulation offers superior spatial and temporal control compared to other cellular manipulation techniques. This study enabled development of the tools required for achieving sonogenetic manipulation of cells by presenting novel transducer designs and identification of relevant parameters in order to achieve stimulation of transfected cells.
High-resolution remote acoustic localization of damage in vibrating plates
Authors: Flynn Tyler J. , Dowling David R.
Published: November 2019

Two major challenges exist for the remote acoustic localization of damage in vibrating structures. First, the presence of damage typically results in small acoustic changes that may become “drowned out” by the majority of the sound which remains unchanged. To mitigate this, a high-resolution beamformer can be used to better resolve the acoustic sources, including the small changes (i.e., damage). However, this elicits the second challenge; many popular high-resolution beamformers exhibit poor performance in the presence of coherent sources—exactly the type of sources provided by extended, vibrating structures like a plate. To address both challenges, the Spectral Estimation Method with Coherent Background Removal (SEMCBR) is introduced, enabling the localization of small acoustic changes in a distribution of coherent sources. SEMCBR is an extension of the existing Spectral Estimation Method with Additive Noise (SEMWAN), which has previously been applied to quantify incoherent aeroacoustic sources, combined with an additional subarray averaging step to suppress coherent cross-terms. Experimental results using SEMCBR are provided for the localization of cuts, fastener faults, and delamination in 30-×-30-×-0.16 cm plates base-excited from 100–6000 Hz, using an 8-×-8 array of remote receivers. [Sponsored by NAVSEA through the NEEC and by the US DoD through an NDSEG Fellowship.]
SPNet: Automated object detection of antinode regions in oscillating steelpan drums
Authors: Hawley Scott H. , Morrison Andrew C.
Published: November 2019

We present a machine learning computer program which applies a neural-network-based object detection algorithm to individual frames of high-speed video of oscillating Caribbean steelpan drums obtained via electronic speckle pattern interferometry (ESPI). This algorithm is trained in a supervised learning context on a dataset of crowd sourced human-annotated images obtained from the Zooniverse Steelpan Vibrations project. The computer code, which we call “SPNet,” is subsequently able to annotate new frames of similar images in a manner consistent with the humans' prior work, albeit much more quickly—hundreds of frames per second. The goal of this annotation work is to better understand the dynamical behavior of these drums such as the coupling of oscillations in different parts of the drum surface, by tracking the development of sympathetic vibration modes and extracting their relevant physics. We present details of the algorithm, performance metrics, and some preliminary physics results.
The physics of knocking over LEGO minifigures with time reversal focused vibrations
Authors: Barnes Lucas A. , Brown Aaron C. , Anderson Brian E.
Published: November 2019

Time reversal (TR) is a method of focusing wave energy at a single point in space. This project optimizes a TR demonstration designed to knock over one selected LEGO minifigure among other minifigures by focusing vibrations within an aluminum plate at the target minifigure. The goal is to achieve high repeatability of the demo along with making it possible to do at a lower cost. By comparing the motion of the minifigure and the plate directly beneath its feet, it was determined that a major factor inhibiting the repeatability of the demo was that smaller vibrations leading up to the focal event caused the minifigure to bounce repeatedly, losing contact with the plate and ending up in the air during the main focal event intended to knock over the minifigure. This project explores the effects of amplitude, frequency, TR technique, plate size, and vibration sensor type on the repeatability of the demonstration. This demonstration illustrates the power of TR focusing and the principles learned by optimizing this demonstration can be applied to other real-world applications.
Near shore atmospheric acoustic transmission loss: Numerical predictions
Authors: Turo Diego , Ryan Teresa J. , Vecchiotti Andrea , Judge John , Vignola Joseph F.
Published: November 2019

This work presents advances in the development of a numerical model of atmospheric acoustic propagation designed for a littoral or riverine environment with a near-shore acoustic source and on-shore receivers. A parallel experimental effort uses a measurement system that records concurrent atmospheric and acoustic transmission loss data. The numerical model uses a generalized terrain parabolic equation method to account for sea surface roughness and ground topography along the propagation path. The model accounts for vertical temperature and wind speed profiles as well as surface impedance at the shore. For the comparison with experimental data, wind speed is used to predict the sea state. The propagation range consists of three segments: over water, over swash and sandy shore, and over complex dune with highly varied vegetation of up to 2 m height. Surface impedance estimates for the sandy shore are made based on grain size distribution and impedance tube measurements of excised samples. Existing models for surface impedance of vegetation were used for the dune portion of the propagation range.
Fearless steps: Taking the next step towards advanced speech technology for naturalistic audio
Authors: Hansen John H. L. , Joglekar Aditya , Sangwan Abhijeet , Yu Chengzhu
Published: November 2019

Over the past two decades, machine learning technologies have been targeting real-world problems in the Speech-Language (SLT) domain. Speech corpora developed under diverse environments have been paramount to progress, though most are simulated/controlled scenarios. Success in Machine Learning for SLT requires new innovative challenges posed by multi-speaker naturalistic audio. The UTDallas-CRSS led Fearless Steps (FS) initiative over the past 6 years has made significant strides through the development of the Fearless Steps Corpus, and multiple novel schemes to address core speech tasks. The next steps taken through this initiative aim at motivating further research on these data through worldwide collaborative efforts. To achieve this, the Inaugural Fearless Steps Challenge held in 2019 saw the release of 11 000 h of Apollo-11 audio data and diarization transcripts, made freely available to public online. An additional 100 h of manually annotated data was released as a Challenge corpus, available to researchers interested in working on any of the five core speech tasks: Speech-Activity-Detection, Speaker Diarization and Identification, Speech Recognition, and Sentiment Detection. FS Challenge resulted in over 150 participants worldwide developing novel task-specific algorithms. Going forward, the FS initiative aims at digitizing and releasing over 150 000 h of the remaining Apollo Missions in conjunction with follow-on Challenge Tasks focused on developing multi-channel and conversational speech systems.
Production and perception of English vowels preceding voiced and voiceless consonants by Korean learners of English
Authors: Chung Juyeon
Published: November 2019

In English, consonant voicing has large effects on the previous vowel duration, as does the status of the vowel as tense or lax. Our aim is to examine whether there is an interplay between L1 interference and L2 experience on L2 English vowel productions and perceptions. Korean L2 speakers were chosen as participants; Korean has no contrasts in tense versus lax vowels, and no coda consonant voicing contrast in a monosyllabic structure, but exhibits post-vocalic voicing contrasts in disyllabic structures, and in these cases, voiced consonants exhibit the lengthening of the preceding vowel. The participants were asked to read the list of English nonce words consisting of the English high and mid vowels and sets of plosives contrasting in voicing as a coda in the two different structures. In an ABX discrimination task, the subjects were asked to identify the different words from among minimal triples. None of the speakers exhibited different patterns in both structures in productions or perceptions. All speakers exhibited durational correlates to the voicing contrast, and to the tense-lax distinction. The effect of L2 English experience was not shown in perception task. Overall, there was no correlation between vowel length differences in production and perception scores.
Automatic detection and classification of sounds generated by ocean vehicles via cyclic demodulation and beamformed coherence
Authors: Zhu Chenyang , Mohebbi-Kalkhoran Hamed , Seri Sai Geetha , Makris Purnima R.
Published: November 2019

Narrow-band tonal signals generated by ocean vessels are a dominant source of underwater sound, occurring at discrete frequencies ranging from several Hertz to several kiloHertz and continuously over long time intervals. Here we develop a two-stage approach for the automated passive acoustic detection and classification of underwater vehicles. The first stage utilizes the commonly used cyclic demodulation to extract the low frequency tonal sound modulated into high frequency noisy signal from which the fundamental frequency and blade pass frequency of ship propeller can be determined. The second applies magnitude-squared coherence to beamformed signals to directly extract tonal sounds spanning a wide range of frequencies from low (∼10 Hz) up to the array cutoff frequency and to estimate their bearings. Both the modulated and unmodulated tonal signals generated by a ship can be simultaneously determined using this two-stage approach leading to a more complete spectral characterization of the underwater sound radiated by an ocean vessel. Here, the approach is applied to analyze and characterize the underwater sound generated by research vessel RV Knorr, received on a large-aperture densely populated coherent hydrophone array.
An information theory approach to assess acoustic-environmental significance
Authors: Bhatt EeShan C. , Viquez Oscar A. , Novitzky Michael , Schmidt Henrik
Published: November 2019

Autonomous underwater vehicles (AUVs) rely heavily on the acoustic environment for tasks related to sensing, navigation, and communication. In advanced applications of these vehicles, such as those involving hazardous or highly dynamic regions, their internal representation of the oceanic environment can prove essential to the mission success. Our current method is a virtual ocean simulator described by environmental empirical orthogonal functions (EOFs), a pre-determined set of sound speed perturbations; and corresponding recombination coefficients, weights assigned to recreate a specific sound speed profile that can be updated via acoustic communication. Given the limited bandwidth of acoustic communications, it is necessary to transmit the most vital information to update the virtual ocean representation—the minimum necessary to most effectively capture the real-time variability. Here we present the framework for determining the acoustic significance and uncertainty of an environmental coefficient-EOF pair, using an upcoming experiment in the Beaufort Sea as a case study. [Work supported by the Office of Naval Research.]
Performances immersed in or interacted with unique environmental contexts
Authors: Chiang Weihwa
Published: November 2019

By selecting the 100 soundscapes in 1996 and coordinating follow-up events in 2002, the Ministry of the Environment, Japan drew the attention to rediscover and preserve unique sounds across the country. The diverse soundcapes are associated with wildlife, natural phenomena, or man-made sounds from industrial or cultural activities. In addition to appreciating the sound events, performances at outdoor Noh stages in Japan were immersed in unique environmental context historically. Bird chirping, wind blowing, and sea tide may all become the context of the play. Similar situation could be found for historical plays of Chinese operas at the stage integrated with a Chinese garden. There are modern facilities or events designed to immersed in or interacted with natural or man-made context. Some take advantage of unique acoustic effect such as echoes in valleys while the others create focus by isolating ambient disturbances and integrating soundscapes with visual, functional, or other forms of environmental qualities.
Longshan Temple soundscape
Authors: Tsaih Lucky S. , Kuo Yi-Ting
Published: November 2019

Longshan Temple, built in 1738, is one of the most visited historical religious places in Taipei. Longshan Temple was built with Chinese Siheyuan style, which is a traditional courtyard housing style. The objective of this soundscape pilot study is not only to identify and document the sound sources and paths in the temple but also to learn the perceived affective quality through the assessment of surrounding sound environment. The questionnaire used is suggested by ISO 12913. Binaural audio, video recording, and real-time sound pressure level were taken. The results show that sound from human being is dominated in the temple. The present surrounding sound environment is good with pleasant, eventful, and calm as the perceived qualities. With the measured equivalent sound pressure level at 68.9 dBA and “very loud” as the listening impression of temple, the soundscape of the temple is still rated with the pleasant and appropriated sound environment.
Addressing challenges in automated whistle extraction
Authors: Gruden Pina , White Paul R.
Published: November 2019

Automated extraction of dolphin whistles from field recordings presents a challenging problem, as typically these recordings are noisy, contain multiple overlapping whistles and interfering signals. This results in many spurious detections, partial extraction and fragmentation of the whistle contours, which could cause problems for applications such as whistle-based localization. This paper presents the probability hypothesis density (PHD) filter, a non-traditional whistle tracking method based on multi-target Bayesian framework. Two implementations of the PHD filter, one based on Gaussian mixtures and one based on particle methods, are adapted for this task and tested on a large real-world dataset consisting of six dolphin species. The proposed filters successfully track simultaneous whistles, and compare favourably to standard methods. Moreover, it is shown how the proposed methods can be used to enhance the localization efforts with linear towed arrays.
Use of spatial context to increase acoustic classification accuracy
Authors: Palmer Kaitlin , Helble Tyler A. , Nosal Eva-Marie , Ierley Glenn , Fleishman Erica , Shiu Yu , Liu Xiaobai , Gillespie Douglas M. , Cholewiak Danielle , Klinck Holger , Roch Marie A.
Published: November 2019

Making classification decisions on the basis of multiple calls from the same class (e.g., species) can reduce the classification error that is attributable to variance. In many cases, clustering acoustic signals from multiple classes on the basis of location information can allow for separation and simultaneous classification of those calls. Source location and call timing are the most common criteria for clustering calls into groups or tracks. However, in many studies, widely spaced arrays or internal clock drift render a large proportion of the detected calls non-localizable. We built flexible clustering systems that incorporate all time difference of arrival values from calls detected by two or more sensors. We developed three clustering algorithms and used Monte Carlo simulations to compare their clustering accuracy and classification error. The algorithms increased clustering accuracy and reduced classification error by 2%–20% relative to grouping by time (a common fusion strategy) or classification of individual calls. These results demonstrate the ability of imperfect spatial information to improve classification accuracy of vocally active species.
Physical mechanisms of generation of the noise bursts associated with nonlinear internal tides in shallow water
Authors: Katsnelson Boris , Godin Oleg A. , Zhang Qianchu
Published: November 2019

Recent paper of authors [J. Acoust. Soc. Am. 145(3, Pt. 2), 1670 (2019)] reported observations of repeated increase in acoustic noise intensity during passage of trains of nonlinear internal gravity waves. Periodic increases of pressure fluctuations by up to 35–40 dB in the frequency band from 10 to 5000 Hz were recorded on multiple near-bottom hydrophones during Shallow Water 2006 experiment. The present paper extends the earlier analysis to a more diverse set of nonlinear internal wave events by exploiting the acoustic data obtained at sites with a wider range of water depths and over a longer observation period. Three distinct physical mechanisms are identified, which are responsible for increased noise in different frequency bands. The observed noise bursts are attributed to turbulence of the water flow past hydrophones, sediment transport, and sediment saltation. Correlation between the velocity of the internal tide-induced near-bottom currents and noise intensity at low and mid-frequencies is investigated. [Work supported by ONR, NSF, and BSF.]