bluuebunny/crossref_metadata_2025 huggingface dataset:
Errors and uncertainty: Why acoustical measurements and predictions can never be precise
Authors: Putnam Robert , Peppin Richard J.
Published: December 2020

Throughout the disciplines of airborne sound measurement and prediction, the matter of uncertainty continues to be given short shrift. Rare indeed is the field survey report, or the community noise modeling prediction, that openly addresses the unavoidable uncertainty inherent in all such measured data, in every airborne noise prediction, or even in the measurement methodology employed. Several times over past decades the authors have reminded the community of acoustical professionals of these serious limitations. A refresher is long overdue. Herein will be reviewed (a) why absolutely every acoustical measurement anywhere under any circumstances will have a precision no better than 1 dB, (b) the careless omission of the “Confidence Interval” being employed, whenever uncertainty is addressed at all, (c) the inevitable upward creep in sound level resulting from multiple source uncertainties, and (d) the often overwhelming influences of atmospheric and vegetation inhomogeneities. The proper methods for combining these several elements of uncertainty are given.
An acoustic-based road traffic monitoring method
Authors: Marciniuk Karolina , Kostek Bozena
Published: December 2020

The paper shows an acoustic-based road traffic monitoring method and its capabilities of utilizing it in the road system management. First, the acoustical signal acquisition process is shown. The database development and the methodology of audio signals preprocessing are described. Next, selecting appropriate parameters used to detect the presence of the vehicle on the road is discussed. The detected events are subjected first to the statistical evaluation related to intervals between vehicles (safe distance criterion), and then classification is carried out. Several methods for classifying vehicle types based on their sound are employed, using four classes of vehicles. Additionally, the method of assessing traffic safety is presented with regard to the vehicle tire adhesion with the road surface—by acoustic detection of the presence of water and snow on the roadway. The effectiveness of 0,968 has been obtained for the type of a vehicle, whereas 93.3% for detecting humidity on the road surface. [The project is financed by the Polish National Centre for Research and Development (NCBR) from the European Regional Development Fund under the Operational Programme Innovative Economy No. POIR.04.01.04-00-0089/16 entitled: INZNAK – “Intelligent road signs for adaptive traffic control, communicating in V2X technology.”]
Acoustic radiation force on a compressible spheroid
Authors: Jerome Thomas S. , Ilinskii Yurii A. , Zabolotskaya Evgenia A. , Hamilton Mark F.
Published: December 2020

The acoustic radiation force on a compressible spheroid is calculated using expansions of the scattered field in terms of both spherical and spheroidal wave functions. There is no restriction on the size or acoustic impedance of the spheroid, the structure of the incident field, or the orientation of the spheroid with respect to the incident field. The solution is the same as that developed previously for the radiation force on an elastic sphere, which is expressed as a summation of terms involving products of the coefficients in spherical wave expansions of the incident and scattered fields [Ilinskii etal., J. Acoust. Soc. Am. 144, 568–576 (2018)]. Spheroidal wave expansions are used to satisfy the boundary conditions on the compressible spheroid, and far-field asymptotes are used to relate the spheroidal and spherical wave scattering coefficients analytically. Explicit expressions for the scattering coefficients are available for spheroids with rigid or free surfaces. Results are compared with available analytical solutions for various limiting cases. The theoretical framework may be employed for objects of arbitrary shape provided the spherical wave expansion of the scattered field is known. [T.S.J. is supported by the Applied Research Laboratories Chester M. McKinney Graduate Fellowship in Acoustics.] a)Deceased.
Extraordinary trapping by Gorkov potential of ordinary and vortex limited-diffraction beams
Authors: Fan Xudong , Zhang Likun
Published: December 2020

Trapping behaviors by using standing waves or focused beams have been investigated and widely used for acoustic levitation and tweezers. It is commonly understood that dense and stiff particles are repelled from pressure anti-nodes (pressure maximum) where the Gor'kov potential has a maximum. Here, the trapping behaviors of a small particle by using Gor'kov potential of ordinary and vortex non-diffracting beams are examined. Unlike the standing waves or strongly focused beams, the ordinary non-diffracting beam with proper parameters is found to have a Gor'kov potential minimum at its pressure maximum to trap a relatively dense and stiff particle therein [Fan and Zhang, Phys. Rev. Appl. 11(1), 014055 (2019)]. For a vortex beam to trap a dense and stiff particle at the pressure null, the paraxiality of the beam has to be larger than some values. These seemly to be extraordinary behaviors are interpreted by the contribution of axial velocity to the Gor'kov potential. The results are applicable to beams with weak diffraction or weak focusing. Following from the results, ways to simplify methods for particle manipulation and development of acoustic tweezers are suggested.
A 3-D-printed acoustofluidic device for Raman spectroscopy
Authors: Santos Harrisson D. , da Silva GiclÃªnio C. , da Silva Amanda E. , de Andrade José H. , da Silva Carlos Jacinto , Moreira Magna S. , Silva Ueslen , Silva Glauber T.
Published: December 2020

The development of technologies capable of determining direct information about cell status is highly required. Confocal Raman microscopy offers a singular pathway to monitoring chemical “fingerprints” of intracellular components via radiation-complex biomolecules interactions. Nevertheless, Raman spectroscopy's biological applications are still challenging due to the small probability of spontaneous light scattering events with bio-micromolecules. As a consequence, the signal-to-noise ratio is low. Acoustofluidic devices offer an ingenious solution to enhance the Raman signal by levitating the biological sample. In this work, we present a cheap 3-D-printed acoustofluidic device for confocal Raman spectroscopy. The device comprises a cylindrical cavity with a 750 μm-height and 4 mm-diameter, which operates around 1 MHz. Raman spectra of polystyrene microparticles (10 μm-diameter), levitating at 300 μm in water, were obtained by using a 785 nm excitation laser focused through a 40x objective lens. In another set of careful experiments, the device efficiently trapped 20-μm macrophages (cell line j774.A1), of which the preliminary Raman spectra will be presented. Finally, we will discuss Raman spectroscopy's trends as an optoacoustofluidic technique, as well as its applications in biotechnology and microbiology.
Trap-and-release of motile microorganisms using glass-based standing surface acoustic wave devices
Authors: Cui Mingyang , Meacham John M.
Published: December 2020

Standing surface acoustic waves (SSAWs) are an effective tool for cell manipulation and isolation in many biological and biomedical applications. Chlamydomonas reinhardtii, a unicellular motile microorganism, is an excellent biological model to study ciliary mechanics; however, its swimming strength is a challenge for trapping and analysis by conventional non-contact methods. SSAW devices incorporating polydimethylsiloxane (PDMS) channels are unable to hold C. reinhardtii due to inadequate acoustic trapping forces at power levels that do not induce excessive heating. Under operating conditions that are suitable for trapping, the sample temperature increases rapidly to exceed the thermotolerance threshold of the cells leading to loss of function or death . In this study, we show that SSAW devices with wet-etched glass channels allow for gentle trap-and-release of C. reinhardtii using 10 and 25 MHz ultrasound while traditional SSAW devices with PDMS channels kill the cells. In addition, we use infrared thermography to confirm that PDMS-based SSAW devices reach significantly higher temperatures than glass-based devices at comparable input powers. Glass-based SSAW devices easily generate the required trapping forces while maintaining a biocompatible thermal environment.
Perceptual consequences of pauses: Credibility and fluency of native and non-native speech
Authors: Houghton Zachary N. , Kato Misaki , Baese-Berk Melissa M. , Vaughn Charlotte
Published: December 2020

Silent pauses are a natural part of speech and impact perception of speech. However, it is unclear how foreign accentedness influences perception of pauses. Specifically, studies have shown mixed results regarding whether listeners process pauses in native and non-native speech similarly or differently. A possible explanation for these results is that perceptual consequences of pauses differ depending on the type of processing that listeners engage in: a focus on the content/meaning of the speech versus characteristics/form of the speech. Thus, the present study examines the effect of silent pauses on listeners' perception of native and non-native speech in two different tasks, examining perceived credibility of the information conveyed in the speech, and perceived fluency of the speech. Specifically, we ask whether characteristics of silent pauses (e.g., presence or absence of a pause; syntactic location of a pause) influence listeners' perception differently for native versus non-native speech, and whether this pattern differs for perceived credibility and fluency. The results help us better understand how disfluency and foreign accent together impact listeners' perception. Further, this provides insight for how perceptual consequences of certain acoustic properties of the speech differ depending on how listeners are asked to evaluate the speech.
The relationship between word error rate and perceptual judgment
Authors: Park Seongjin , Culnan John
Published: December 2020

The aim of the present study is to examine the relationship between word error rate (WER) from an automatic speech recognition system and perceptual judgments (foreign-accentedness, fluency, and comprehensibility) from human raters. In a previous study, Franco et al. (1997) used HMM-derived scores based on posterior probabilities of phone segments, and Deville et al. (1999) used an HMM/ANN recognition approach to show how the results of automatic speech recognition can be used for perceptual judgments. Park and Culnan (2019) showed the possibility to assimilate human raters' perceptual judgments by using neural network models only with the speech signal, and suggested that the model worked better on accentedness judgments than fluency judgments. In this study, we will examine whether WERs of English sentences produced by three language groups (American, Korean, Chinese) are significantly different, and if there is any difference, we will analyze the correlations between WER and perceptual judgments. The perceptual data used in Park and Culnan (2019) will be used for the analysis. The preliminary results of this study will be used to find important features to build more accurate automatic proficiency judgment models.
Talker differences in clear and conversational speech: Perceived emotional valence
Authors: Young Elizabeth D. , Ferguson Sarah H.
Published: December 2020

Clear speech, a speaking style talkers adopt when talking to individuals with hearing loss, is often described as sounding “angry” (e.g., “I try to speak clearly, but when I do, he thinks I'm mad at him”). Previous research has indicated that listeners do indeed rate clear speech as “angry” or “disgusted” more often than conversational speech. However, this same research found that some talkers can increase the clarity of their speech without sounding angry. The present study expands the previous work by testing perceived emotion for 41 talkers in order to examine talker differences in the perceived emotional valence of clear and conversational speech. Perceptual ratings from 25 young adults with normal hearing will be gathered using an online experiment interface. Stimuli consist of 14 emotionally neutral sentences in both clear and conversational speaking styles from 41 talkers. Listeners will be asked to “judge the emotion you think you heard in that sentence” using a six-alternative, forced-choice paradigm for thefollowing emotional categories: “anger,” “fear,” “disgust,” “sadness,” “happiness,” and “neutral.” It is anticipated that the current study will increase our understanding of how perceived emotional valence in clear and conversational speaking styles varies among talkers.
Visual scanning of a talking face when evaluating segmental and prosodic information
Authors: Deng Xizi , Yeung Henny , Wang Yue
Published: December 2020

Prior work has shown that the mouth area can yield articulatory features of speech segments and durational information (Navarra et al., 2010), while pitch and speech amplitude, are cued by the eyebrows and other head movements (Hamarneh et al., 2019). It has been reported that adults will look more at the mouth when evaluating speech information in a non-native language (Barenholtz et al., 2016). In the present study, we ask how listeners' visual scanning of a talking face is affected by task demands that specifically target prosodic and segmental information, which has not been examined by the prior work. Twenty-five native English speakers heard two audio sentences in English (the native language) or Mandarin (the non-native language) that might differ in segmental or prosodic information, or even both, and then saw a silent video of a talking face. Their task was to judge whether the video matched either the first or second audio sentence (or whether both sentences were the same).The results show that although looking was generally weighted towards the mouth, reflecting task demands, increased looking to the mouth predicted correct responses only for Mandarin trials. This effect was more pronounced in the Prosody and Both conditions, relative to the Segment condition (p < 0.05). The results suggest a link between mouth-looking and the extraction of speech-relevant information at both prosodic and segmental levels, but only under high cognitive load.
Audiovisual enhancement and single-word intelligibility in children's speech
Authors: Munson Benjamin
Published: December 2020

It is nearly axiomatic that audiovisual (AV) speech is more intelligible than audio-only (A-only) speech, particularly when the speech is presented in a challenging listening environment, such as in background noise [e.g., MacLeod and Summerfield, Br. J. Audiol., 2 (1987)]. Surprisingly, there has been only limited exploration of differences between individual talkers in the intelligibility advantage of their AV speech over their A-only speech. In this work, we ask whether different age groups of speakers elicit systematically different AV benefits in speech intelligibility tasks. A recent study examined whether children and adults' speech elicits similar AV benefits for sentence intelligibility (Karisny et al., J. Acoust. Soc. Am. 146). In that study, children's speech elicited smaller AV benefits than adults' speech, though this comparison was complicated by suboptimal choice of different signal-to-noise ratios to equate the groups' intelligibility in A-only conditions. The current study follows up on this work by examining single-word intelligibility in the same talkers, using a single SNR for both groups. Data collection is ongoing. Results will help us understand the role of individual-speaker variation on the magnitude of AV benefit.
Linking domain knowledge and machine interpretation using braid theory and cognitive sampling: Applications to underwater acoustics, and machine interpretation of melodic structures in North Indian classical music
Authors: Sen Gupta Ananya , Kubicek Bernice , Sobieski Kevin , Majumdar Tejendra
Published: December 2020

Learning domain-interpretable features unbiased by model uncertainties is challenging due to training bias, incomplete model knowledge and human subjectivity. It is challenging to solve this dilemma due to limitations of available training data, incomplete or conflicting models, as well as lack of integrational framework that resolves model inconsistencies to build an unbiased feature dictionary. We introduce a novel sampling strategy called cognitive sampling that allows combining domain knowledge and machine interpretation to influence spectral sampling using geometric constructs such as braid, knots and links within the dataset, and thus enhance the accuracy of machine classification beyond so-called “black box” techniques. Beyond representative results from traditional applications such as underwater acoustics, we will also explore machine-driven music cognition based on melodic structures (Raags) from North Indian classical music. The Raag tradition exhibits intricate yet improvised melodic structure that cannot be easily quantified in Western staff notation due to its fluid forms and presence of microtones. Recent efforts to incorporate learning networks for machine-driven melodic interpretation have been met with partial success, the primary limitation being dearth of expert-interpretable feature engineering. Presented results will be based on underwater acoustic datasets and sarod recordings performed by Pt. Tejendra Narayan Majumdar.
Therapeutic effects of ultrasound on dermal wound healing in diabetic mice
Authors: Vander Horst Melinda A. , Raeman Carol H. , Dalecki Diane , Hocking Denise C.
Published: December 2020

Some evidence indicates that relatively low intensity, pulsed ultrasound can enhance soft tissue regeneration in both animal models and humans. However, the effectiveness of therapeutic ultrasound can vary among populations. Here, we investigated effects of ultrasound on dermal wound healing using a murine model of chronic, diabetic wounds. Full thickness, punch biopsy wounds were made on the dorsal skin of genetically diabetic, male mice. Wounds were exposed to 1-MHz pulsed ultrasound (2 ms pulse, 100Hz PRF, 0–0.4 MPa) for 8 min per day, for either 2 or 3 weeks. After 2 weeks, the average granulation tissue thickness at the center of wounds exposed to 0.4 MPa ultrasound was significantly increased compared to sham-exposed wounds. Interestingly, the mean granulation tissue thickness of one subpopulation of mice exposed to 0.4 MPa was significantly greater than that of a second subpopulation (594 ± 41 μm, n = 9 vs 62 ± 25 μm, n = 10). Increasing the treatment time to 3 weeks increased the percentage of mice with fully re-epithelialized wounds from 47% at 2-weeks to 86%, and significantly reduced wound diameter. These data demonstrate a dose-dependent difference in the responsiveness of young, male diabetic mice to pulsed ultrasound treatment protocols.
Simultaneous transmit and receive for self-sensing in ultrasonic measurement systems
Authors: Byrne Matthew S. , Haberman Michael R. , Alu Andrea
Published: December 2020

Simultaneous transmit and receive (STAR) systems have recently enabled sending and receiving of radio-frequency (RF) signals at the same time and at the same frequency using a single antenna. This has led to commercialization efforts with the promise of doubling the throughput of traditional radio systems, including Wi-Fi and future 5G cellular communications. Prior to these advances, researchers in vibration control have been developing self-sensing actuator systems, also referred to as sensoriactuators or sensorless control systems. Inspired by these developments, we combine and extend these approaches to explore the development of STAR functionality in an acoustic measurement system at ultrasonic frequencies. We apply self-interference cancellation (SIC) to a time domain measurement in order to demonstrate the potential for a practical, single-transducer ultrasonic nondestructive evaluation (NDE) system to measure continuous echo returns while it is actively transmitting at the same frequency. Theoretical models and preliminary experimental results will be presented and discussed.
An alternative approach to window ANC
Authors: Thompson Stephen C. , Dittberner Andrew
Published: December 2020

Outdoor noise can enter an office workspace through an open window. An active noise Control system Is described that can provide global reduction in the workspace of noise from outside the window. The system uses (1) a microphone array outside the window to detect the magnitude and direction of incoming sounds; (2) a sparse array of loudspeakers in and around the window to radiate sound into the office space to cancel the entering outside sound, and (3) a processing system to derive appropriate signals from the microphone array to drive the speaker array to achieve cancellation. The sparse array leaves the window mostly open and unobstructed. Array shading coefficients that match the radiation pattern of the array to that of the window aperture can be derived in advance. ANC processing on each outdoor noise source provides the signals to drive the cancellation array. A feedforward system built to this design concept should provide reasonable cancellation with minimal window obstruction and fewer optimization channels than a more conventional window cancellation system.
Are fitness instructors at risk of hearing impairment?
Authors: Sliwinska-Kowalska Mariola , Zaborowski Kamil R. , Wolniakowska Anna , Dudarewicz Adam , Pawlaczyk-Luszczynska Malgorzata
Published: December 2020

The entertainment industry can pose a risk of hearing impairment to employees. The aim of the study is to assess whether occupational exposure to loud sounds (music) is related to temporary hearing threshold shifts in fitness instructors. The study comprised a total of 29 fitness instructors working in fitness clubs. The noise dosimeters were used to determine individual noise exposure during typical 1-2 hours exercises conducting by the instructors. Pure-tone audiometry and Hearing in Noise Test (HINT) were performed before and just after the session to assess temporary changes in hearing. The A-weighted equivalent-continuous sound pressure level (LAeq,T) during typical exercises session ranged from 76.3 to 96 dB. Referring to the 3-dB equal energy rule, such exposures may exceed the upper exposure action value (85 dB) set for the occupational settings by the Directive 2003/10/EC. A significant temporary threshold shift (at least 6 dB) was observed in 33 audiograms (40 %). No impairment of speech understanding was observed in the HINT. Fitness instructors may constitute a population at increased risk of hearing impairment. Further studies are needed to conclude on hearing protection programs in this group of workers.
Acoustic trapping of sub-wavelength microparticles and cells in resonant cylindrical shells
Authors: Lin Qin , Cai Feiyan , Li Fei , Xia Xiangxiang , Zheng Hairong
Published: December 2020

Acoustic tweezers based on the sound beam systems hold the promise of contactless manipulation of microparticles. However, in these conventional diffraction-limited system, acoustic diffraction severely limits the trapping strength and the minimum size of the trapped particles. Here, we theoretically propose and experimentally demonstrates that a simple cylindrical shell based acoustic tweezers can be utilized for trapping of sub-wavelength particles and cells with a radius as small as 1/400 of the corresponding acoustic wavelength. This mechanism is attributed to the significantly enhanced acoustic radiation force originating from the resonant excitation of low order circumferential mode intrinsically existing in the cylindrical shell, which is a highly localized field around its surfaces and breaking the diffraction limit. We further demonstrate that the manipulation ability of these tweezers is significantly stronger than that of traditional standing wave based acoustic tweezers, which can significantly reduce physiological damage to cells or other biological objects arising from the thermal effects. Thus, the cylindrical shells based acoustic tweezers are simple, disposable, low cost, biocompatible, and functional, with applications including 3-D bio-printing, cell culturing and tissue engineering.
Equivalence of three-dimensional acoustic radiation force and torque formulas based on angular spectrum and multipole expansion methods
Authors: Gong Zhixiong , Baudoin Michael
Published: December 2020

Acoustic radiation force (ARF) or torque (ART) can be derived by integrating the time-averaged linear and angular radiation stress tensor (the flux of momentum tensor) over a far-field standard spherical surface including an arbitrarily shaped target. Following this idea, there are three sets of independent original derivation on the ARF ([Silva, J. Acoust. Soc. Am. 130, 3541–3544 (2011)] and [Baresh et al., J. Acoust. Soc. Am. 133, 25–36 (2013)] based on the multipole expansion method, and [Sapozhnikov and Bailey, J. Acoust. Soc. Am. 133, 661–676 (2013)] based on the angular spectrum method); and two independent work on the ART ([Silva et al., EPL 97, 54003 (2012)] based on the multipole expansion method and [Gong and Bandoin, J. Acoust. Soc. Am. (under review; 2020)] based on the angular spectrum method). In this work, we formally establish the equivalence between the expressions obtained by these two methods with the relation of beam shape coefficients at different elementary waves of the field for both the force and torque. The differences between the existing formulas in the literature are indicated and explained. The respective advantages of each form are discussed.
The freedom to move around—Introduction of the Sonova real life lab
Authors: Klockgether Stefan , Ulloa Sanchez Diego , Vercammen Charlotte , Derleth R. Peter
Published: December 2020

In experiments, control is everything. If parameters, procedures or the environment cannot be controlled thoroughly, any experiment lacks repeatability and hardly any findings can be generalized. In psychoacoustics and audiology research, important aspects of perception in real life are sacrificed in favor of control. The new “Real Life Lab” at Sonova allows audiological research to take a big step forward towards real life environments by bringing the freedom to move around in acoustic environments to controlled laboratory conditions. The lab provides a large stage where persons can move around freely, interact with acoustic or real objects, or with simulated or real people. The stage is surrounded by a framework of loudspeakers to present acoustic content from all directions and screens to present visual content in the horizontal plain. Any motion by persons on the stage can be tracked in real time with a motion capturing system. The motion capturing data can be passively tracked during any experiment or it can be actively used to alter or trigger audio and video reproduction. This contribution shows the technical capabilities of the lab together with some insights on the first experiment on the motion behavior in an orientation task in a complex acoustic environment.
An improved procedure for shape preserving design of vibrating structures using topology optimization
Authors: Silva Olavo M.
Published: December 2020

The shape preserving design approach by topology optimization was firstly introduced for linear static problems, in which the local strain energy of a controlled domain inside a given structure is constrained with a minor upper bound beyond zero, designated to suppress its warping deformation (and, consequently, preserving its shape even when the whole body deforms). Shape preserving design applied to structures subjected to harmonic loads was explored in a recent article, but without reporting the difficulties found throughout the numerical processes. In that research, the local dynamic compliance was used in its classical form as a local measure of deformation/warping. In the present work, the author shows that instabilities arising from the use of such measure as a constraint function make the procedure unstable and slow. The frequency behavior of the classical dynamic compliance is directly related to the involved displacement and force responses, presenting antiresonances within a given frequency range. This fact may cause instabilities and early convergence of the optimization process. Thus, it is suggested the constraint on the local time-averaged potential energy for a better controlling of deformation/warping of specific regions in a given structure. Some examples are presented and discussed, which indicate the effectiveness of the proposed procedure. In addition, more physical meaning can be found by using this measure instead of the classical dynamic compliance as a constraint function.
Neumann accelerations of generalized polynomial chaos expansions for larger dynamic systems
Authors: Kaminski Allison , McDaniel James , Liem Alyssa
Published: December 2020

This work proposes a method for accelerating generalized polynomial chaos (gPC) expansions, using Neumann series, for uncertainty quantification of complex structures with uncertain damping and spring parameters. Often, classical Monte Carlo simulations are used for uncertainty quantification, however, for larger systems and frequency sweeps this method becomes very computationally expensive. Neumann series have been used with Monte Carlo simulations to decrease computation times, however, the Neumann series does not always converge. More recently gPC expansions have been used for uncertainty quantification. gPC is a stochastic spectral method that develops a surrogate model, whose coefficients can be used to calculate statistical moments. gPC requires sampling the response at predetermined quadrature points, which may become expensive for large systems. This study proposes a new approach where Neumann series are used to calculate the response at gPC quadrature points, in order to accelerate gPC computation times. The validity of this method is shown using large, viscously damped systems. Damping and stiffening elements fully connect degrees of freedom to each other and to ground. First the damping elements are taken as the uncertain parameter, then stiffening elements are taken as the uncertain parameter, and frequency dependent responses such as power dissipated are calculated.
Developing a cross-platform federated code repository for speech research
Authors: Redmon Charles H. , Kelley Matthew C. , Tucker Benjamin V.
Published: December 2020

The increasing proliferation of code, scripts, and programming language libraries for use in speech science research raises concerns over the maintenance and organization of this disparate code base. These concerns have motivated us to explore the development a federated code repository under the umbrella of the Acoustical Society of America. Our primary goal for this repository is to serve as a central point from which researchers in the speech sciences can access code and data from the community that adheres to a set of established standards for documentation. The code will also be reviewed by other researchers for errors, vulnerabilities, and algorithmic misspecifications. Further, this repository will serve as a starting point for the future development of parallel libraries in open-source languages like R, Python, and Julia. In this talk, we will outline our plans for the repository and identify key open challenges and questions to be answered by contributors regarding repository structure, the code submission and review process, and documentation standards to adopt.
A cloud-computing platform for developing and evaluating vocal biomarkers based on home audio recordings: Resources for large-scale data processing and analysis
Authors: Ramsay Gordon
Published: December 2020

This presentation describes the design and construction of a comprehensive cloud-computing platform for implementing and evaluating vocal biomarkers, both for assessing typical development of speech and language and detecting deviations in autism. As part of a prospective longitudinal study of early vocal development (NIH P50 MH100029), whole-day home audio recordings were collected from more than 300 children every month from birth to three years using LENA, providing long-term, large-scale sampling of each child's natural environment. The database contains more than 40 000 h of raw audio data, post-processed acoustic measures, event timing statistics, hand-coded and automated annotations, as well as sociodemographic and clinical metadata, the storage, integration and processing of which has presented significant new challenges. Flexible cloud solutions have been adopted to allow secure cross-platform shared access and referencing of the data. Customized modular “C” code libraries for physical modeling, spectral analysis, temporal event labeling, voice activity detection, speaker diarization and developmental profiling have been developed, based on standard BLAS/LAPACK libraries optimized for device-independent virtual machines, and integrated with an interactive graphical interface for signal analysis and labeling. Resources and specific challenges for large-scale analysis of infant vocalizations will be discussed.
Acoustic source centering of musical instrument directivities using acoustical holography
Authors: Bellows Samuel , Leishman Timothy W.
Published: December 2020

The acoustic center of a source is commonly defined as the point from which spherical wavefronts appear to diverge. Measuring directivities of sound sources with a surrounding spherical array whose geometric origin is not aligned with the acoustic center of the source can lead to distortions in directivity patterns. Thus, a method is desired to obtain both the far-field directivity pattern and to determine the acoustic center of a source. This work illustrates how acoustical holography can identify the reference frame from which spherical waves diverge by studying various musical instruments' acoustic centers.
Sound propagation in Arctic-like waveguides
Authors: Dmitriev Konstantin , Lipavskiy Alexey , Pankov Ivan , Sergeev Sergei , Fomin Grigorii
Published: December 2020

Sound propagation in Arctic-like waveguides (regions with a strong interaction of the acoustic field propagating in the water layer with both ice cover and the bottom) is complex phenomenon. The authors have performed more than two dozen experiments in different seasons on the shelf of the White Sea and in Moscow region both in the active regime and in the noise interferometry regime. In the active regime, it was demonstrated that the presence of ice leads to a decrease in the critical frequencies of the modes. If the bottom gives off gas, its accumulation under the ice layer significantly affects the boundary conditions. Flexural waves propagate over the ice and can radiate energy into the water layer. Interference occurs and is significant, especially near and below the cutoff frequency of the waveguide. Ice movement causes crackling. Using the acoustic noise caused by the crackling as a signal (noise interferometry regime) on the Arctic shelf allowed to solve the inverse problem and to reconstruct the sea parameters, for example, tidal activity. Using several horizontally spaced hydrophones, it was possible to study the processes of the propagation of individual cracks in the ice.
Modeling environmental uncertainty in ocean propagation simulations
Authors: Johnson Jay R. , Lee Brandon M. , Dowling David R.
Published: December 2020

The ocean is a dynamic random environment and predictive ocean acoustics tasks generally require knowledge of environmental parameters. To understand the extent to which environmental uncertainty impacts acoustic field calculations, each of the environmental parameters can be considered a random variable and to contain temporal and/or range dependence. Many computational ocean acoustics tasks, such as assessing the impact of anthropogenic noise sources, designing ocean propagation experiments, and finding commercial aircraft emergency locator beacons, would benefit from leveraging the underlying uncertainty in these properties to yield more accurate and robust predictions. However, appropriate sampling of ocean environment properties to quantify acoustic uncertainties can be difficult. While in-situ studies can rely on repeated experimental data collection and direct measurements of uncertainties to deduce the impact of varying environmental state, computational studies do not often have efficient or robust tools for incorporating uncertainty. In this talk, a framework is presented to sample uncertain ocean environmental states using open-source databases to predict acoustic uncertainties. Example Monte-Carlo simulation results for acoustic amplitude and phase at frequencies from 100 to 500 Hz are presented for propagation ranges up to 100 km.
The update of Urick’s Principles of Underwater Sound
Authors: Wiseman Charles H.
Published: December 2020

For over 50 years Principles of Underwater Sound by Robert Urick has been a widely used book on underwater acoustics and sonar for practicing engineers, scientists, technicians, project managers, teachers and students and it is in the last stages of an extensive update to be released this spring. The book encapsulates the fundamentals and phenomena of underwater sound as applied to the Sonar Equation, the heart of prediction of sonar performance, and the book’s contents lie squarely in the middle between theory at one end and practical technology at the other. The editor and contributors of the update have attempted to imbue the new edition with the same “blue collar” spirit of Urick’s original work but with so much new technology to address since the present edition was published in 1983, it’s been difficult to keep the updated printed edition to a convenient size. Therefore, in addition to the traditional printed book edition, we are introducing a new e-book edition which will provide more detail than the printed edition. This presentation includes: (1) Descriptions of the two new formats (2) Examples of updated technology, and (3) New subjects: sonar transmissions’ effect on the health of marine mammals; sea floor mapping; locating downed airliners; and search plans.
Sound field studies in archaeological fieldwork: near or far, free or direct or diffuse field—How does it matter?
Authors: Waller Steven J.
Published: December 2020

The relatively new discipline of archaeoacoustics faces challenges regarding the wide variety of prehistoric and historic environments to be studied. This paper focuses on the need to consider different types of acoustic techniques to use in various situations. Hypothesis testing can potentially lead to different results depending on the type of acoustic testing performed. Nearfield versus farfield approaches can yield disparate datasets, so the methodology chosen can have significant impact on the conclusions. How do sound reflecting surfaces affect the sound power radiated from a source, or received by a listener, and influence its apparent directionality and cultural perception? Examples of acoustic research results will be presented, including studies of deep cave paintings of Europe, shallow painted shelters of India and Australia, and petroglyphs carved into the walls of canyons and cliff faces in North America.
The acoustics of the “clapping circle” at Purdue University
Authors: Wing Elspeth A. , Herr Steven J. , Petty Alexander D. , Dufour Alexander K. , Hoham Frederick H. , Merrill Morgan E. , Samphier Donovan W. , Thor Weimin , Singh Kushagra , Xue Yutong , Huston Davin H. , Bolton J. S.
Published: December 2020

The unusual acoustical properties of a particular landscape architecture feature of Academy Park on the Purdue University campus have been the subject of speculation for years. The feature, known informally as the “clapping circle,” consists of sixty-six concentric rings of stone tiles. When someone claps while standing at the middle of the circle, they hear a high-pitched squeak immediately afterwards. Experiments were conducted by the Purdue student chapters of the Acoustical Society of America and the Audio Engineering Society to characterize this effect. The response to a clap played from an omnidirectional speaker placed at the center of the circle was recorded using a microphone positioned above the loudspeaker. Spectrograms of the recorded responses revealed the squeak to consist of a descending tone at around 1500 Hz, and its harmonics. This tone disappeared from the spectrogram when the tile rings were covered with absorbing blankets. A mathematical model based on scattering from the gaps between the tile rings reproduced the descending frequency of the squeak, and reproduced the effect of the source and receiver height on the rate of change of frequency. Thus, it was concluded that the squeak is an example of repetition pitch produced by the tile formation.
Simulation-validated generative design of acoustical arrays with diffusion and absorption
Authors: Hsu Timothy , Dessi-Olive Jonathan
Published: December 2020

This paper presents several new results for on-going efforts in combining computational design methods and acoustical needs. Past investigations employed rule-based design strategies that expanded upon current monolithic deployment of quadratic residue diffusers (QRD) in the field. The algorithm generated novel, and visually diverse arrays of N = 7 QRD panels. The arrays generated visually strayed from the typical appearance of QRD arrays; appearing more expressive as rules were applied. Furthermore, evaluation metrics including a visual complexity coefficient and 3-D polar plots from PML-FEM simulations provided visual evidence that a relationship exists between the appearance of an array and its corresponding acoustical response. Building on this previous work, representative arrays generated by the output of the algorithms with expanded parameters will be presented alongside updated evaluation metrics. The algorithm uses an expanded set of simulation-validated rules that include non-square grid configurations, multiple design frequencies, a varying number of wells, and incorporate zones of absorption. These new arrays, along with results and discussion of acoustical response to these rules, will be presented. Using these expanded parameters absorption, field of room acoustics design is opened up to wide-ranging visual design possibilities that are fully cooperative and incorporated with the acoustic response.
Analysis and acoustical modeling of transit noise reflections to residential locations
Authors: Maurer Alex
Published: December 2020

As development progresses in urban areas, it is common that new projects are developed adjacent to existing public transportation systems. Varying in dimensions and façade materials, these new developments introduce new surfaces off of which sound can reflect to locations previously not impacted. The acoustical ramifications of the facades of new developments are often ignored and can create reflections to residential locations that are additive to the direct sound of the transit system. These reflections can be subjectively regarded by nearby residents as bothersome or intrusive. We have studied one such case of reflected transit noise adversely impacting nearby residents. We measured short duration sound pressure levels (Lps) of the transit activity near the affected residential locations and created a three-dimensional sound propagation model to better understand the impact of transit noise reflections off of two nearby residential developments, comparing the results of our study with Federal Transit Authority Guidelines.
Acoustofluidic-mediated molecular delivery to human T cells for improved immunotherapies
Authors: Patel Riyakumari K. , Priddy Mariah , Murphy Emily , Stamp Bryce , Centner Connor , Bates Paula , Yaddanapudi Kavitha , Kopechek Jonathan A.
Published: December 2020

Cell-based immunotherapies, such as CAR-T therapy, have recently demonstrated significant efficacy for treatment of blood cancers and other diseases. However, current methods of cell loading and processing for these therapies are time-consuming, expensive, and inefficient, which limits patient access and safety of this potentially life-saving therapy. To address these limitations, we are developing a novel 3-D-printed acoustofluidic system which integrates ultrasound (5 MHz) and a flow chamber to consistently induce molecular delivery to cells as they pass through the system sequentially. We conducted experimental studies to evaluate the efficiency of molecular delivery to human Jurkat T cells using the acoustofluidic system in combination with ultrasound contrast agents. Intracellular delivery of a fluorescent compound, calcein, was measured via flow cytometry. Acoustofluidic treatment significantly enhanced calcein delivery to Jurkat T cells by 51 ± 27% compared to untreated control groups without ultrasound exposure (p = 0.005). Cell viability, as measured with propidium iodide staining, was not compromised by acoustofluidic treatment (93 ± 5% viability). Our experiments revealed enhanced delivery of calcein to human T cells while maintaining cell viability. Further development of this platform technology may lead to improved cell loading and processing methods for cell-based immunotherapies or other applications.
Histotripsy of a collagen tissue-mimicking phantom
Authors: Elliott Jacob C. , Smallcomb Molly , Simon Julianna , Vidt Meghan E. , Khandare Sujata , Butt Ali A.
Published: December 2020

Collagenous tissues, such as tendon, have proven resistant to mechanical fractionation by histotripsy. Evidence on B-mode ultrasound images suggests the successful creation of boiling bubbles and/or cavitation bubble clouds in these collagenous tissues; however, the oscillation and collapse of the bubbles does not result in tissue fractionation. Here, tissue-mimicking collagen gels were placed at the focus of a 1.5-MHz HIFU transducer and insonified at various pulse lengths and repetition frequencies. Cavitation activity was monitored passively with a Philips/ATL L7-4 imaging transducer (Bothell, WA USA) and Vantage® research ultrasound system (Verasonics, Kirkland, WA, USA) and compared to high-speed photographs (Photron Nova S-9, Tokyo, Japan). Preliminary results in the tissue-mimicking collagen phantoms show violent cavitation activity and rapid gel fractionation with conventional histotripsy parameters, which is dissimilar to what is observed in highly collagenous tissues. To address this limitation, we will explore phantoms with superior fiber alignment, such as fibrin gels, which will allow for evaluation of histotripsy parameters that promote mechanical fractionation in highly collagenous tissues. [Work supported by NIH R21EB027886 and NSF GRF #DGE1255832.]
Susceptibility to impulsive noise: A review of early studies
Authors: Flamme Gregory , Deiters Kristy K. , Tasko Stephen M.
Published: December 2020

The maximum tolerable exposures returned by damage-risk criteria for impulsive noise are often designed to protect the population to the 5th percentile most susceptible exposed person. To protect human research volunteers, estimates of this location on the distribution must be estimated rather than measured directly. In this presentation, we present threshold shift distributions from human studies of threshold shifts prior to about 1980. Sample sizes ranged in these studies ranged between 5 and 66 ears. The threshold shift distributions implied by these data are compared against assumptions made in more recent damage-risk criteria for impulsive noise. Implications for the development and/or improvement of damage-risk criteria will be discussed.
Acoustic wave propagation and reciprocity in a toroidal waveguide carrying a mean flow
Authors: Thompson Charles , Kamal Sarah , Hu Lejun , Chandra Kavitha
Published: December 2020

In this paper acoustic wave propagation in a toroidal waveguide of rectangular cross-section carrying a circumferentially directed mean flow is analyzed. The typical length scale of variation of the pressure is given by the circumference L0 , the height of the waveguide H0 and the gap ΔR$. Of particular interest are cases where ε = H0/L0 is much less than one. It is shown that flow reverse symmetry of the acoustic pressure gives rise to nonreciprocal behavior between select points along the toroid's circumference.