bluuebunny/crossref_metadata_2025 huggingface dataset:
The generalized finite amplitude insert substitution method for estimation of the ultrasound parameter of nonlinearity
Authors: Panfilova Anastasiia , Chen Xufei , Sloun Ruud J. , Wijkstra Hessel , Sapozhnikov Oleg A. , Mischi Massimo
Published: December 2020

The estimation of the ultrasound parameter of nonlinearity (B/A) has shown promise for improved tissue characterization. The finite amplitude insert substitution method (FAIS) is a simple technique that measures B/A. It derives B/A based on the ratio between the 2nd harmonic generated in a reference medium (known B/A) and in the sample of interest, measured in transmission mode between a source and a receiver transducer. The classical FAIS was presented for media with a linear frequency dependence of attenuation, and assumes the sample to be positioned close to the receiver. In this work, the FAIS was generalized to allow arbitrary sample positions and arbitrary frequency dependence of attenuation. The introduced generalization of the method and the utilized setup for B/A measurement were validated by measuring B/A in corn oil and 2 animal tissues: porcine liver and porcine fat, whose B/A are known. The experimental conditions which optimize the accuracy of the estimated B/A were also investigated. The mean B/A for the chosen measurements was 10.8 ± 0.8 for oil (ref. B/A = 10.3), 5.1 ± 0.8 for porcine liver (ref. B/A = 6.9) and 11.9 ± 1.6 for porcine fat (ref. B/A = 10.9), showing the feasibility of B/A measurement by the proposed generalized method.
Advanced sonic boom propagation model based on a single-ray Jacobian
Authors: Lonzaga Joel B.
Published: December 2020

A sonic boom is a nonlinear event whose propagation can be modeled involving two stages. The first stage consists of ray path calculations using linear approximations, while the second stage deals with a nonlinear transport of the acoustic energy along these paths. This presentation discusses a second-order finite difference numerical approach used to predict the ray paths in range-dependent atmospheres and compares it to existing finite difference schemes. The approach is validated using exact solutions obtained for stratified atmospheres. In the second stage, the geometrical spreading effect needed in determining sonic boom waveforms from a Burgers' equation is obtained using a method that only needs a single ray rather than four rays required by most existing sonic boom propagation codes. The single-ray method calculates the Jacobian, associated with the coordinate transformation from a suitable ray coordinate system to the Cartesian coordinate system, directly from the ray tracing equations. While the four-ray method approximates the geometrical spreading using a finite difference scheme involving the four rays, the single-ray method does not rely on this approximation and instead depends purely on the acoustical kinematic properties of the atmosphere. Comparisons of results using these two methods are discussed.
Ray tracing for efficient simulation of curved sound propagation paths: Towards real-time auralization of aircraft noise
Authors: Schäfer Philipp , Vorlaender Michael
Published: December 2020

Thanks to modern auralization methods, simulated aircraft flyovers can be experienced in virtual environments. Listening to such an auralization provides a more sophisticated impression of annoyance of aircraft noise in real scenarios than reading averaged sound pressure levels or noise maps. For proper auralization results, translation and refraction due to wind and to inhomogeneity of the atmosphere should be taken into account, which leads to curved sound propagation paths. However, state of the art auralization tools including these effects do not allow real-time simulations on CPUs. In this work, an efficient ray tracing tool for simulating curved propagation paths between an aircraft and a listener is introduced. The performance and limitations are discussed for a typical aircraft trajectory. The benchmark results suggest that real-time auralization of aircraft noise using ray tracing is possible if the processing of propagation paths in the overlying auralization framework is extended accordingly.
Ray methods in architectural acoustic design
Authors: Dulworth Nicolaus T. , Strong John T. , Giegold Carl
Published: December 2020

Raytracing is a simple but powerful tool in acoustics consulting because of its ability to geometrically approximate wave behavior across a large portion of the audible spectrum. The use of this method requires an understanding of the frequency-dependent interaction between sound waves and geometry, which is a wave-specific behavior that any use of ray-based approximations must consider. The limitations of these approximations may necessitate geometric modifications in a model to render credible results, or may even dictate raytracing is inappropriate for a given application. Ray-based analysis can be used for applications with a wide range of complexity, from hand-traced sketches to computational simulation for full-scale rooms. Common applications include analysis of reflector coverage, design of room shape and major room components, and impulse response simulation for analysis and auralization. Due to their efficiency and simplicity, ray methods remain indispensable in architectural acoustic analysis.
Strategies for teaching a musical acoustics class online
Authors: Piacsek Andrew A.
Published: December 2020

Physics of musical sound is a first-year undergraduate course at Central Washington University that has been offered for over 20 years. The course is normally taught in a studio classroom format that utilizes peer instruction. Over the past few years, much of the course content and many of the exercises have been adapted to an online course management system (Canvas), enabling a significant degree of flipped teaching. Instead of a textbook, extensive use is made of online resources, including simulations, sounds, and free audio software. In 2018, I took this a step further and developed a fully online version of the course to be offered during the summer session. The goal was to replicate many elements of the traditional in-person class, including student interactions and facilitating a final project that involves constructing or analyzing a musical instrument. This presentation will emphasize the design and efficacy of three particular class elements: (1) online discussions based on a reading or video; (2) small group projects, including lab activities; (3) a term project culminating in the design and construction of a musical instrument.
Playing to learn: Hands-on activities in the musical acoustics classroom
Authors: McNeil Laurie
Published: December 2020

The physics of musical instruments is a topic that often appeals to students who might not otherwise take a physics course. These students (and the physics majors!) respond very well to active-learning approaches in which they are led to explore the mathematics and physics they are learning by means of real objects making real sounds. I will describe the activities I have incorporated into a course for first-year undergraduates that I have co-taught with a colleague from the Music Department for two decades. Students demonstrate phenomena on instruments they play, make measurements of vibrating strings and air columns, produce vibrating reeds from drinking straws, design wind chimes, and build novel (and often comical) stringed and wind instruments out of found objects. The class culminates in a concert in which students perform their own compositions for ensembles of those instruments. I will relate the success of these activities to the findings from physics education research that underpin them.
The influence of Elliott Berger in shaping occupational hearing loss prevention
Authors: Driscoll Dennis
Published: December 2020

It was at the June 1979 ASA meeting in Cambridge where I first me Elliott Berger. We were introduced by Larry Royster, who was our graduate professor at N.C. State University. Elliott had long departed before I started my graduate program, but the echoes of his past still reverberated throughout Larry's acoustics lab. I will elaborate more during my talk. I started my professional career in occupational noise in mid-1980. For almost the next forty years I worked with Elliott on several professional association committees, participated in countless seminars and conferences, toiled over the AIHA Noise Manual, 5th Edition (and pending 6th), and have enjoyed his friendship since that day in 1979. As a scientist, Elliott has consistently and steadfastly worked to assure and improve the protection of individuals from occupational noise. As a peer, he has provided mentorship to not only me, but many of the experts in this field. The topic of my talk will cover a summary of Elliott's prolific contributions to the cause of hearing loss prevention.
Elliott Berger's role in the standardizing measurements of hearing protection devices
Authors: Murphy William J. , Wells Lauraine L.
Published: December 2020

Elliott Berger has been perhaps the most influential person in the development of standards for hearing protection devices within the Acoustical Society of America and the broader international standards community. He became involved with the American National Standards Institute (ANSI) S3 working group 10 shortly after he joined Cabot Safety Corporation in 1976. In 1985, Elliott assumed the chair position of ANSI S12 working group 11, which was responsible for the ANSI S12.6, American National Standard Methods for Measuring the Real-ear Attenuation of Hearing Protectors. He worked on developing a rating method that could be consistently implemented in testing labs and which represented the performance of hearing protectors. Thirty-five years later, the methods are largely the same, but have seen a harmonization between ANSI and international standards. This paper will discuss the development of these standards, methods to measure passive, level-dependent, and active noise cancellation hearing protection devices, and methods to qualify hearing protection fit-test systems. Elliott's dedication, meticulous commitment to quality, and leadership have forged consensus amidst diverse interests, leaving a lasting impact on occupational hearing loss prevention.
Considerations for enhancing the perception of frequency-lowered speech
Authors: Alexander Joshua M.
Published: December 2020

Some frequency transposition and all frequency compression methods in today's hearing aids adhere to an untested assumption that spectral features of high-frequency speech cues, namely frication, need to be preserved or replicated after being lowered in frequency. Consequently, recommendations for optimizing the selection of parameters that control this signal-processing feature have focused on maximizing the amount of high-frequency energy moved into the aided audiogram or on maximizing the frequency separation between key speech contrasts after lowering. I will present evidence that suggests that preserving temporal modulation from the original speech at the auditory periphery should be a key consideration for the perception of frequency-lowered speech.
Effect of environmental uncertainty on source localization from mid-frequency tonals using convolutional neural networks
Authors: Neilsen Tracianne B. , Escobar Christian , Acree Mason C. , Hodgkiss William , Van Komen David F. , Knobles David P. , Badiey Mohsen , Castro-Correa Jhon A.
Published: December 2020

In ocean acoustics, the lack of labeled training data creates the need to train on simulated data. The simulated training data need to represent the environmental variability in the anticipated area where acoustic data are collected. Further, the manner in which environmental uncertainty should be incorporated is a significant question facing all ocean acoustics applications of machine and deep learning. To begin addressing this question, a case study is presented using mid-frequency tonal data recorded on a VLA. The time-varying tonal levels are input to a convolutional neural network (CNN) which finds the source range, depth, and speed and seabed type. The CNN is trained on simulated data and then tested on simulated data with different sound speed profiles and seabed types than used in training. The impact of this mismatch on the CNN predictions highlights the need to carefully account for environmental variability during training in order to provide robust machine and deep learning applications in ocean acoustics. [Work supported by the Office of Naval Research.]
Knowledge discovery from comparisons of specialized and conventional metrics determined from acoustic fields and measurements
Authors: Dowling David R. , Lee Brandon M. , Flynn Tyler J. , Douglass Alexander S.
Published: December 2020

Once acoustic signals (information streams) are recorded, there are myriad possible means for extracting and representing the embedded scientific or engineering knowledge that awaits discovery. Given the rich history of acoustic investigations, such knowledge extraction commonly involves comparisons based on conventional or specialized metrics chosen or devised to indicate critical underlying phenomena. Such comparisons may rely entirely on simulation results, experimental results, or a combination of the two. However, a suitable metric must be used in each case. This presentation provides four examples where conventional or specialized metric comparisons indicated new knowledge: (1) performing Monte-Carlo simulations and machine-learning predictions of the probability density function (PDF) of acoustic transmission loss (TL) in uncertain ocean sound channels to attain knowledge of how to best represent PDF(TL) when predicting it; (2) Using simulated acoustic-radiation data from vibrating structures and specialized dilation cross correlation metrics to remotely generate knowledge of experimental damage type and severity; (3) Comparing the measured horizontal coherence of acoustic fields and autoproducts to extract knowledge of their relative coherence lengths and bandwidths; and (4) Scaling of high-Reynolds-number hydrofoil-trailing-edge velocimetry and surface-pressure fluctuations measurements to attain knowledge of the near-wake conditions that lead to tonal noise. [Sponsored by ONR and NAVSEA.]
Utilization of airgun source signatures to improve seismic imaging of ocean water columns
Authors: Zou Zheguang , Zhang Likun
Published: December 2020

Seismic oceanography is a new interdiscipline which uses “legacy” marine seismic reflection data collected by the oil industry to image ocean water columns like eddies and internal waves. Unlike seafloor reflections, ocean water-column reflections are typically weak due to the low acoustic impedance contrast, which challenges seismic oceanography. Utilization of the acoustic characteristics of low-frequency, broadband airgun source can enhance water-column signals for better ocean seismic imaging. Acoustics characteristics of received direct-path, water-column, and seafloor signals are analyzed and applied to design adaptive filtering process to enhance water-column signals. The processing increases the signal-to-noise ratio of water-column signal and attenuates the direct waves without changing the spectral content of the airgun source. The results can be useful to improve seismic oceanography by providing better imaging of ocean water columns.
Knowledge representation in goal-motivated decision making for intelligent active sonar
Authors: Nelson Jill K.
Published: December 2020

We consider knowledge representation in a goal-driven model for intelligent, or cognitive, active sonar designed to improve system performance and reduce sonar operator burden. The intelligent sonar uses observations of the environment (broadly defined) and predictions of future behavior to make decisions that leverage system resources to address a set of goals. These goals are created and managed by the system itself with possible input from the sonar operator. Decisions take the form of action selections, where actions may include transmit waveform, ping interval, illuminated region, etc. Each action is assigned a utility score, or metric, based on how well it addresses each system goal, with weighting according to how simultaneous (possibly competing) goals are prioritized by the system and/or operator. Metrics for evaluating candidate actions rely on signal processing models for localization and tracking in active sonar. To illustrate the impact of the structure of utility metrics on system behavior, we study the performance and decision-making behavior of the intelligent sonar system in simulated scenarios in which the system is tasked with addressing multiple search and track goals simultaneously. The effect of the chosen metric structure on the impact of goal prioritization and operator input is explored and discussed.
Long-term acoustical performance of underlayments under load
Authors: Golden Matthew , Faiz Musafere
Published: December 2020

It is very common to use some sort of a resilient underlayment under gypsum-based topping products in multi-family construction to improve the airborne and impact acoustical performance. To prove acoustical performance, these products are tested in accordance to the relevant ASTM or ISO standards. An assembly is built and then tested in a short period of time. No evaluation of long-term performance is completed. This presentation will compare the performance of crumb rubber based GenieMat and several different plastic mesh entangled filament based underlayments in four key metrics. The first metric is the steady state creep under load. The second and third metrics are the change in performance in both load versus deflection and load versus natural frequency of the underlayments, pre and post steady state creep. The fourth metric is long term change in impact noise levels under load based on small scale testing similar to published standards.
Determining vocal interactions and call timing in chorusing frogs: The contributions of Peter Narins
Authors: Ratnam Rama
Published: December 2020

Numerous species of frogs call synchronously in a chorus by timing their calls to avoid call-overlap with conspecific neighbors. Although synchronous calling is most likely maintained by a call oscillator, several species of frogs including the Puerto Rican treefrog Eleutherodactylus coqui can adjust the timing of the oscillator period over a wide range so as to maintain call synchrony with competing stimuli. Here we describe some of the playback experiments performed by Peter Narins and his co-worker Randy Zelick on the timing capabilities of the oscillator in the coqui frog, particularly the ability to rapidly alter timing even when the silent window had a random onset and was short in duration. Narins recognized that characterizing calling behaviour in isolation, with synthetic stimuli, did not fully describe the acoustic challenges faced by calling males in natural assemblies. Consequently, Narins and his co-worker Jeffrey Brush obtained individual call timings from groups of two to five vocally interacting coqui frogs in a natural assembly. They showed that some males actively avoided call overlap with two, maybe three neighboring conspecifics, while some actively jammed a neighbor. The impact of these seminal studies, and the technical challenges that were overcome by Narins are discussed.
Quantification of the backscatter coefficient in heterogeneous media: Comparison of attenuation compensation methods
Authors: Castañeda-Martinez Laura , Hall Timothy J. , Jafarpisheh Noushin , Whitson Hayley , Rivaz Hassan , Rosado-Mendez I.
Published: December 2020

The estimation of backscatter coefficient, from in vivo tissue requires accurate compensation for intervening tissue attenuation. Current attenuation compensation methods (ACM) have been tested in fully or piecewise homogeneous phantoms. Thus, evidence of their performance in complex media remains scant. In this study we compare the performance of two ACM in a tissue-mimicking material with strong reflectors (SR). A gel-based phantom with SR was scanned with a L11-5v transducer on a Vantage 128 system (Verasonics). Estimates of from the phantom's background were obtained from the IQ echo signals using the known phantom attenuation (KA) or two ACM (a Constrained-Log-Difference (CLD) and a dynamic programming (DP) regularized method).The former method was used as gold standard. To analyze bias versus depth, a Pearson correlation coefficient was computed and the mean difference (MD) vs. depth was estimated. CLD-based showed a strong correlation (r = 0.96) with depth, while the correlation of DP-based estimates was weaker. DP-based values were closer to those obtained with KA (MD [0.9–1.15]) compared to the CLD-based estimates (MD [1.0–1.79]). The DP, regularized ACM show less sensitivity to the presence of SR compared to conventional ACM. We are currently using DP-based ACM to characterize breast lesions.
Spatial characterization of high intensity focused ultrasound fields in the brain
Authors: Schoen Scott J. , Arvanitis Costas
Published: December 2020

High intensity focused ultrasound (HIFU) has seen widespread clinical adoption as a therapeutic tool, as it may be targeted noninvasively and without ionizing radiation. The converging sound waves induce thermal (e.g., ablation) and mechanical (e.g., radiation force) effects that may be localized to manipulate or destroy tissue. In addition to these primary effects, finite amplitude acoustic influences (e.g., second harmonic generation) become relevant due to the high pressure levels near the focal region. Specifically, improved localization of energy at sonic frequencies might be enabled by exploiting these effects. Here, through experimentally validated simulations, we demonstrate the relative importance of acoustical and material properties on the spatial and temporal properties of the resulting focal field, and the feasibility of attaining finite amplitude effects transcranially. While the relative amplitude of the second-order effect was found to scale with the source pressure and nonlinearity parameter, absorption and pulse modulation frequencies influenced both the distribution and spectral content of the field. These effects were observed for a water reference medium, and thus are likely to be even more prominent in tissue. Recent advancements in trans-skull focusing and understanding of the mechanical properties of neurons warrant further investigations, which will aim to explore these higher-order acoustic effects for noninvasive treatment of central nervous system diseases.
Ray tracing for modeling underwater acoustic communications channel between moving platforms, with moving ocean surface and changing bathymetry
Authors: Hursky Paul
Published: December 2020

Underwater acoustic communication systems must contend with a time-varying channel due to motion of source, receiver, point of reflection from ocean surface waves, and point of reflection from the seabed over changing bathymetry. These motions produce Doppler effects, which impact acomms systems. The signal processing to equalize such channel fading typically consists of a number of tracking loops, whose testing requires time varying realizations of such channels. A realistic channel model would enable improved modem designs and hardware-in-the-loop testing. We will focus on how to handle the ocean surface and the changing bathymetry. We propose an architecture which pre-computes the ray tracing for the part of the ocean that is not changing, then updates only small subsets of the ocean where dynamics occur. This consists of identifying the point of specular reflection, then interpolating the source-to-reflector and receiver-to-reflector rays to produce the union of these two paths. Such acoustic paths may be shadowed by the shape of the ocean surface. We will present examples of a time-varying channel impulse response, using the combined travel times, and discuss how dynamic ray tracing can be used to produce the amplitude of the joined paths.
An acoustic impedance probe for the teaching of musical acoustics to non-majors
Authors: Jaeger Herbert
Published: December 2020

Physics of Music or similar titles are found in the course catalogues of many colleges and universities. Almost always such courses are directed at non-physics majors and even non-science majors. As a result the course materials must be presented without reliance on advanced mathematical concepts, and thus a great deal of in-class demonstrations combined with video clips are used instead. For example, the concept of acoustic impedance, when introduced rigorously, requires the use of complex algebra. However, a discussion on a qualitative level can be done in a way that is accessible to undergraduate students without a great deal of math background. In order to introduce some measure of quantitative discussion, we are using a simple home-built impedance probe to record the input impedances of simple air columns as well as real instruments. In this talk we will discuss the details of the impedance transducer and show how it can be used to demonstrate how a flared bell changes the resonances of cylindrical air columns, the effect of differently shaped mouth pieces on the acoustic properties of a brass instrument, and a number of other characteristics of musical instruments.
Solving real-world problems in a physics of music class
Authors: Dostal Jack A.
Published: December 2020

The Physics of Music is a general education science class open to all students at Wake Forest University. Topics covered include wave physics, hearing, voice/singing, musical instrument function and performance (winds, strings, and percussion), room acoustics, and more. We have found great value in applying the concepts learned in class to practical, real-world problems. In the past offerings of the course, students worked on two projects involving Wake Forest's Department of Theatre (musical instruments) and Financial Aid Office (room acoustics). Students in the course communicated in person with students, faculty, and staff in these areas. They later used what they learned in class and discussions to construct equipment for use by the department in question. In this talk, I will describe how these two projects were incorporated into the laboratory portion of the course as well as how connections can be made to uncover other real-world opportunities.
Musical acoustics education in Indonesia
Authors: Parikesit Gea O. , Kusumaningtyas Indraswari
Published: December 2020

As the world's largest archipelago, Indonesia has a vast natural and cultural diversity, and hence a huge variety of musical instruments. Musical acoustics is, therefore, an important field of research and study in Indonesia. However, this subject is still rarely touched in undergraduate education. To help improve the quality of musical acoustics education in Indonesia, we have developed several methods. First, we design a series of final projects for undergraduate engineering students, where they can implement various methods and techniques previously studied in class (e.g., system identification, experimental methods, computational analysis, engineering design) into actual practice. These projects help the students to gain a more comprehensive perspective on the various applications of their knowledge. Second, we form inter-disciplinary collaborations, where the students can learn with musicians, craftsmen, scholars, and conservators. Such collaborations help the students to understand that, by studying the musical instruments, they are supporting the conservation of their own heritage. We have been applying these methods with our students in Universitas Gadjah Mada, particularly in our research on the bundengan, a very unique bamboo-based musical instrument. Our experience indicates that these approaches can be effective to help improve the quality of musical acoustics education in Indonesia.
Creating an acoustic simulation of noise pollution
Authors: Stephens Rian
Published: December 2020

This project utilises acoustic simulations to represent traffic noise pollution and prevention in affected residential areas. Noise has “wide-ranging adverse health, social and economic effects” (Goines, 2007, p. 287). Noise pollution `is more severe and widespread than ever before' and is predicted to worsen with growth in highway traffic (Goines, 2007, p. 287). This paper presents the development of a three-dimensional acoustic model of traffic noise pollution. This three-dimensional acoustic simulation is a computer program that enables the user to walk through a modelled housing estate. Road traffic is programmed to drive along a motorway that runs adjacent to the estate. The user experiences traffic noise pollution in real-time while being given the tools to reduce it. The author examines the techniques of propagating noise pollution in three-dimensional space and how noise level is dependent on average speed, category of vehicle and the average number of vehicles passing through a road section (Kephalopoulos, 2014). Reflection and absorption techniques allow noise to move realistically in 3-D space (Funkhouser, 1998; Shearer, 2007; Murphy, 2007; Rober, 2007).
Optically detected vibrations of crystal pendulum due to sun radiation
Authors: Ostrovskii Igor
Published: December 2020

The optical experiments with suspended quartz crystals reflecting Laser-Doppler-Vibrometer (LDV) beam reveal an effect of crystal pendulum vibrations initiated by Sun's radiation of heavy particles. The LDV measures speed S(t) of oscillating crystal surface. The Fourier-transform of S(t) returns a spectrum of the acoustic vibrations with a few hertz frequency. The S(t) is a sine-type curve with amplitude depending on the time and space orientation of crystal axes. Maximum vibrational speed and corresponding crystal displacement from a position of equilibrium are observed when quartz piezoelectric axis is aimed toward the Sun. Experimental evidences exclude involvement of any electro-magnetic wave. The theoretical calculations for an oscillator driven by a periodic pulse-force are compared to the experimentally detected oscillations. The computations give a work done by an external force to move the crystal from its equilibrium to maximum displacement. It yields a mass of a thinkable particle that is necessary to initiate and support observed vibrations. In the case of individual particles propagating with a solar wind speed and hitting crystal, particle mass is of the order of 10 i×-21 kg. The physics of crystal-particle interaction may be related to gravitational pull of quartz atoms/ions and particle quantum properties such as matter waves.
The WAY to lead—Reflections on the contributions of Dr. William A. Yost to the Speech and Hearing Science Program at ASU
Authors: Zhou Yi
Published: December 2020

In the spring of 2007, after 30 years of Dr. Yost's leadership at the Parmly Hearing Institute at Loyola University Chicago, Dr. Sid Bacon invited him to join the Department of Speech and Hearing Science (SHS) at Arizona State University. Dr. Yost served as the department chair between 2007 and 2013. Dr. Yost brought a clear vision for how auditory research could grow to best position the department in the modern era of brain research. As department chair, he developed a strategic hiring plan to grow the scope of SHS research and expand faculty expertise in critical areas outside the traditional realm of SHS. This hiring strategy resulted in my coming to ASU. This talk will reflect on Dr. Yost's leadership of the department as well as his support for understanding central auditory mechanisms in my laboratory and the example he set for being a model scientist, a devoted teacher, and a productive scholar.
A revisitation of Bill Yost's revisitation of how internal noise affects binaural detection
Authors: Bernstein Leslie R. , Trahiotis Constantine
Published: December 2020

Bill Yost's contributions to knowledge concerning auditory processing comprise several areas of study including binaural masking and discrimination, localizations of sounds (with both static and rotating listeners), binaural and monaural versions of repetition pitch, and mathematical approaches to understanding of each. Perhaps less well-known is his historical and analytical paper concerning estimation and measurement of “internal noise.” In our view, that paper is also a fundamental contribution. Here, we report our related efforts to characterize and to measure types of internal noise that, on the one hand, limit monaural and/or binaural information processing and, on the other hand, help to explain why some listeners with slight, but clinically negligible, elevations in audiometric thresholds exhibit reliable and meaningful deficits in both binaural detection and binaural discrimination tasks. [Work supported by Office of Naval Research (N00014-15-1-2140; N00014-18-1-2473)]
Where versus what: The relationship between speech understanding and auditory motion processing
Authors: Warnecke Michaela , Litovsky Ruth Y.
Published: December 2020

Most sounds involve motion, either because the sound source moves, or the listener does. Thus, perceiving moving sounds is critical for listeners' functional ability to navigate auditory environments. Studies to date focused on the limits of sound motion detection. By contrast, we are interested in the functional importance of auditory motion perception and aim to understand which acoustic cues govern listeners' classification of sound motion. In the present study, we hypothesized that auditory motion perception is influenced by the extent to which stimuli are perceived as intelligible. Utilizing Chimaera compositions of speech and spectrally matched noise tokens, we varied the envelope type and number of frequency channels of acoustic stimuli, manipulating speech intelligibility. Stimuli were presented in free field as stationary or moving. Normal-hearing adults judged sound motion in a 2-AFC task, and verbally repeated what they understood. Results show that a speech signal envelope biased sound motion judgments to be stationary, and increasing speech intelligibility further increased bias. This suggests that speech intelligibility influences auditory motion perception, and that sound motion and speech may not be processed simultaneously. [Work supported by NIH-NIDCD(R01DC8083), NIH-NICHD (U54HD090256) and ASA's Hunt Fellowship.]
Characterizing the physical limitations of phase-only metasurface design for acoustic holograms
Authors: Parker Samuel D. , Kang Janghoon , Treweek Benjamin C. , Skeens Joe , Walsh Timothy , Haberman Michael R.
Published: December 2020

Numerous recent studies have shown that acoustic metasurfaces (AMS) can be used to control reflected or transmitted wave fronts. Acoustic holograms have commonly been created by designing a metasurface that applies local phase changes to a wave front to construct arbitrary pressure fields at one or more image planes. The hologram design process typically features iterative methods, such as the Iterative Angular Spectrum approach. However, metasurfaces that apply phase-only modulation are restricted in the quality of the pressure field reconstruction that can be achieved, especially when attempting to create different holograms at different planes for a single-frequency incident wave. The control of magnitude and phase by an AMS is of significant interest because it enables one to completely define an entire reflected or transmitted wave field in a 3-D region. In the present work, the physical limitations in simultaneously reconstructing multiple single-frequency holograms at different planes via phase-only metasurface design are examined. Methods for overcoming these limitations, including both amplitude and phase control by an acoustic metasurface, are also investigated. Comparisons between simulation and experiment are made for a multi-image reflective hologram system. [S.N.L. is managed and operated by NTESS under DOE NNSA Contract No. DE-NA0003525.]
Predicting wave propagation in periodic lattices with internal resonators
Authors: Kelsten Matthew , Norris Andrew N.
Published: December 2020

Periodic lattice metamaterials like that of the square honeycomb, hexagonal honeycomb, and kagomè lattices have proven themselves useful in structural applications with their ability to strongly suppress vibrations over a broad range of frequencies at subwavelength scales. There have been many attempts in recent years to supplement their dynamic features with the use of internal resonators, creating additional band gaps for heightened overall performance. However, the broad definition of an internal resonator in this context means that it can be difficult to model all cases extensively. In an attempt to help bridge the analytical gap, we consider 2-D lattice designs with incorporated cantilever beam-type internal resonators. Doing so allows for a FEM technique to be used that treats each lattice, and its embedded resonators, as a collection of Timoshenko beams. With it, we can create global mass and stiffness matrices that serve as the driving force behind the characterization of band diagrams and their modal structure. A semi-analytical modeling approach is introduced which highlights the explicit dependence of band diagram features on resonator parameters. The general methodology is discussed, and numerical results are compared with simulated results generated through COMSOL Multiphysics.
Three-dimensional periodic multifunctional lattice materials for simultaneous vibration isolation and heat conduction
Authors: Patil Ganesh U. , Babatola Oluseyi , Hsieh Daniel , Sinha Sanjiv , Matlack Kathryn
Published: December 2020

Thermomechanical applications need materials with higher thermal conductivity and vibration mitigation capability; these functionalities are often interconnected and difficult to optimize simultaneously. Lattice materials are known to exhibit bandgaps by virtue of their rational structural design and periodicity; however, they are inherently thermally resistive, limiting their use in thermomechanical applications. Past efforts towards designing multifunctional materials are focused either on static-dynamic or static-thermal properties. In this talk, we present a design platform for a three-dimensional multifunctional lattice material for simultaneous vibration mitigation and heat conduction within the same structure. We integrate “heat pipes” inside lattice trusses to improve the thermal conductance while we vary the material distribution at the truss junctions, denoted as "nodal mass,” to generate full bandgaps. Through numerical analysis, we show independent control of both functionalities, showing the versatility of our design. Our design achieves an increase in specific thermal conductance by 3 orders-of-magnitude while opening full bandgaps at structural vibration frequencies around 2–10 kHz. Further, we study the anisotropic thermal conductance and the effect of nodal mass fractions on bandgaps of various lattices to facilitate their selection for a specific application. This study opens up the application of lattice materials for demanding environments.
Contributing spectral regions to subjective intelligibility of dysphonic speech in noise
Authors: Ishikawa Keiko , Monson Brian B.
Published: December 2020

Dysphonia negatively affects speakers' intelligibility in noisy places. Although this problem is well-recognized, little is known about the relationship between acoustics and intelligibility of dysphonic speech. The purpose of this study was to identify spectral regions critical to the intelligibility deficit in dysphonic speech. Sentences from the Consensus of Auditory-Perceptual Evaluation of Voice were recorded from 18 speakers with dysphonia and 3 age-gender matched speakers with healthy voice. The intensity of the speech samples was normalized at 60 dB SPL, and cafeteria noise was added to these recordings at a signal-to-noise ratio (SNR)-3, 0, and + 3. Perceived (i.e., subjective) intelligibility of these stimuli was rated on a 7-point scale by 45 native speakers of American English with normal hearing. Spearman rank correlation tests were conducted to evaluate the association between subjective intelligibility ratings and spectral energy in the following frequency regions: 0–8 kHz, 8–16 kHz, 0–1 kHz, 1–2 kHz, 2–4 kHz, 4–6 kHz, 6–8 kHz, 8–10 kHz, 10–12 kHz, 12–14 kHz, and 14–16 kHz. The results indicated that the energies in 8–16 kHz, 0–1 kHz, 1–2 kHz, 6–8kHz, and 10–12 kHz ranges were significantly associated with the subjective intelligibility ratings. The clinical relevance of the findings will be discussed.
Articulatory and acoustic phonetics of voice actors
Authors: Feehan Colette
Published: December 2020

Voice actors are an under-utilized population for linguistic study. This type of vocal performance requires actors to perform careful, consistent, and precise vocal tract manipulations to portray different character types such as imitating a dialect or performing complex manipulations that simulate a smaller vocal tract to sound younger. There has been relatively little research focusing on voice actors' unique vocal tract manipulations. Some previous studies have looked at how actors alter laryngeal setting, to portray specific characters types in animation (Teshigawara and Murano, 2004; Starr, 2015), but investigations of articulatory manipulations employed are rare. Even more rare are investigations focusing on these articulatory manipulations and how they link to the acoustic output. This study uses 3-D ultrasound and acoustic analyses to compare the kinds of articulatory strategies that actors use to approximate a smaller vocal tract and achieve a ‘childlike' acoustic percept. Preliminary analyses indicate that actors have many different types and combinations of manipulations that they can implement including hyoid bone and laryngeal raising, gesture fronting, tongue grooving, lip movement, and F0 manipulation. Despite these differences in approach, the actors still achieve similar child-like percepts. This poster compares strategies from 3 professional and 3 amateur actors (4 male and 2 female) and will describe within-subject variation across each actor's adult and imitated child voices.
Laryngeal-acoustic relations in smiled speech
Authors: de Boer Gillian , Derrick Donald , Schellenberg Murray , Gick Bryan
Published: December 2020

Smiling is a social signal that can be both seen and heard. Smiling can increase speech amplitude and raise F0 and formants. However, experimental research on the role of larynx height in smiled speech is limited. 21 English speakers (6 M) repeated words in a carrier phrase with a neutral face or while smiling. The participants were recorded with audio, video and laryngeal ultrasound. F0, F1 and F2 were extracted for the duration of target vowels /i/, /u/ and /a/. Ultrasound images of laryngeal position were measured using Optical Flow. The laryngeal and acoustic data were analyzed in R with linear mixed models with smiling condition, timepoint-in-vowel, and gender as fixed effects. There was a significant effect of timepoint-in-vowel for larynx height (raising towards the end) and a smile-timepoint interaction effect (the larynx raised more at the end for smiling condition). Acoustically, smiling led to significantly higher F0 across vowels, and significantly higher F1 and F2 for /a/ but not /i/ or /u/. F2 timepoints were significant for all three vowels (F2 trajectories differed) across smile conditions. Results indicate smiling has a consistent effect on larynx height and variable effect on specific speech sounds.
A pilot study on the acoustic characteristics of ambiguous sentences in highly intelligible individuals with Parkinson's disease
Authors: Kuo Christina , Barrett Matthew
Published: December 2020

Phonetic and semantic ambiguities have been documented with internal open junctures, where phonemes in the same order occur at varied linguistic boundaries and often with different prosodic patterns [Lehiste, Phonetica 5 (Suppl. 1), 5–54 (1960); Fisher and Logemann, Q. J. Speech 53(4), 365–373 (1967)]. As such, internal open junctures offer unique opportunities for evaluating the intricate speech-language interplay [Spencer and Wollman, Lang. Speech 23(2), 171i–198 (1980)]. In this study, sentences containing internal open structures were examined for individuals with Parkinson's disease (PD) of high sentence intelligibility. Given prosody and speech timing are commonly impacted in PD, it is hypothesized that internal open junctures may provide a context for detecting subtle speech changes before intelligibility is reduced. Ambiguous sentence pairs were produced by four males with the diagnosis of PD and two neurologically healthy males as a part of a larger study. Data from male speakers were studied to control for potential effects of sex in this pilot. Segment (sentence, juncture, and pause) duration, articulation rate, second formant (F2) trajectory, and fundamental frequency (F0) contour were analyzed. Specifically, the research question of interest is whether the acoustic characteristics associated with internal open junctures in PD differ from those of healthy individuals. This research is supported by a 4-VA Collaborative Research Grant (https://4-va.org/) awarded to the authors.
Acoustic characteristics of conversational and clear speech produced in quiet and in noise by older adults with hearing loss
Authors: Ferguson Sarah H. , Morisak Paige D. , Thurston Sara , Willson Kylie N. , Hunter Eric
Published: December 2020

When communication occurs in noise or with hearing-impaired listeners, talkers often modify their speech. Speech produced in noise, or “Lombard speech,” and speech produced by talkers instructed to speak as though their communication partner has a hearing loss, or “clear speech,” usually feature a reduced speaking rate and a higher and more variable voice pitch than quiet and/or conversational-style speech. Both styles are also generally more intelligible than quiet/conversational speech. Although clear speech in particular is meant to accommodate the needs of listeners with hearing loss, most of the talkers in previous studies have been young adults with normal hearing. We hypothesize that talkers with hearing loss, having experience as listeners with hearing loss, would better know what listeners with hearing loss need than talkers with normal hearing, and that the magnitude of the acoustic differences would change accordingly. In the present study, talkers aged 65–85 years with bilateral mild-to-moderately severe sloping sensorineural hearing loss were recorded reading sentences in quiet and in the presence of white noise under instructions to speak conversationally and then clearly. Acoustic differences between the styles for these talkers will be compared to those observed previously in young normal-hearing adults using the same recording protocol.
Battlefield acoustics: Applications and challenges
Authors: Alberts W. C. K.
Published: December 2020

Some primary objectives of research and development for battlefield acoustic sensing include the optimization of sensors, arrays, and signal processing algorithms for the detection, localization, and classification of diverse broadband and transient threats in complex environments. Time-difference-of-arrival and frequency domain signal processing techniques using distributed microphone arrays allow sound source localization and tracking through triangulation in the 3-D space. This presentation will introduce general applications of broadband acoustic and infrasonic microphone arrays, acoustic particle velocity sensors, geophones, propagation environment effects and wind mitigation methods.