bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear unsteady energy analysis of structural systems
Authors: Culla Antonio , Pepe Gianluca , Carcaterra Antonio
Published: June 2017

The problem of vibration of large systems undergoing shocks and unsteady loads is one of the field of great interest in vibro-acoustic engineering. Statistical Energy Analysis-SEA is one of the most acknowledged methods in this field. However, SEA has many limitations, and is based on several questionable hypotheses. In the present paper, on the basis of a new theory of vibration thermodynamics, the authors consider a set of systems characterized by (i) unsteady loads, such as shocks, (ii) nonlinear coupling between the different subcomponents. The analysis is carried on considering different prototype systems, starting from a very simple pair of nonlinear resonators, a 2-dof system, up to consider a system of plates coupled through nonlinear joints. It is shown how the energy flow relationship between subsystems pair, comes out to be a power series of the energy storage difference. These results are systematically considered in the light of the thermodynamic theory of vibrating systems, showing how a general energy approach to complex systems is feasible.
Diffuse elastic waves in a nearly axisymmetric body: Distribution, transport, and dynamical localization
Authors: Weaver Richard , Yoritomo John
Published: June 2017

We report measurements on the distribution and evolution of diffuse ultrasonic waves in elastic bodies with weakly broken axisymmetry. Aluminum cylinders with dimensions large compared to wavelength were excited by transient point sources at the center of the upper circular face. The resulting power spectral density was then examined as a function of time and frequency and position. It was found that this energy density showed a marked concentration at the center at early times, a concentration that subsequently slowly diminished towards a state of uniformity across the face, over times long compared to ultrasonic transit time across the sample. The evolution is attributed to scattering by symmetry breaking heterogeneities. Relaxation did not proceed all the way to uniformity and equipartition, behavior shown to be consistent with Enhanced Backscatter and with Dynamical Anderson Localization among subspaces of different angular momentum.
The impact of context and competition on speech comprehension in younger and older adults revealed using eye-tracking and pupillometry
Authors: Ayasse Nicole , Wingfield Arthur
Published: June 2017

Although younger and older adults can use context effectively to understand spoken language, at times the context may fit multiple semantic competitors, and choosing the correct one can be crucial for comprehension. Given the ambiguities present in the real world, and the inhibitory control deficit common in aging, it is critical to understand how adults of all ages comprehend sentences. An experiment is reported to explore the interplay of context and competition in sentence comprehension using a variation on a visual world eye-tracking paradigm. Spoken sentences were presented with either high or low expectancy (context) for a sentence-final (target) word and with either high or low response entropy (uncertainty or competition); these target words were then paired with either a contextual competitor or an unrelated lure. Results support the expectation that lower context and greater competition slow comprehension and increase cognitive effort. Results will be discussed in terms of aging and individual differences. [Work supported by NIH Grants RO1 AG 019714 and T32 GM 084907.]
Three-dimensional analysis of liquid sounds produced by first graders
Authors: Foley Olivia , Piper Amy W. , Lulich Steven M.
Published: June 2017

The liquids /r/ and /l/ in American English are complex sounds whose productions are highly variable among adult speakers, but there is currently little knowledge about how children articulate these sounds, which are typically acquired late in development. In this study, the Goldman-Fristoe Test of Articulation (GFTA-3) was administered to typically developing first graders (6 and 7 years old) while a 4D ultrasound system imaged the tongue with synchronous audio and webcam video recordings. The GFTA-3 contains words in which /r/ and /l/ occur in a variety of syllable positions and phonetic contexts. Among 14 first grade participants in this study, the so-called “bunched /r/” is overwhelmingly preferred over the so-called “retroflexed /r/.” In contrast, three-dimensional tongue shapes in the production of syllable initial /l/ are substantially more variable with two basic configurations (“coronal” and “dorsal”), while syllable final /l/ productions are more consistently “dorsal.” Examples of 3D tongue shapes will be presented, along with results from a Principal Components Analysis.
Differentiating infant cry from non-cry vocalizations based on perception of negativity and acoustic features
Authors: Yoo Hyunjoo , Bidelman Gavin , Buder Eugene , van Mersbergen Miriam , Oller David K.
Published: June 2017

This study seeks to determine how human listeners discriminate cry vs. non-cry sounds by investigating acoustic factors that may contribute to the perception of negativity in infant vocalizations (e.g., cry, whine, and vowel-like sounds). The assumption is that identification of cry is self-evident; therefore, there has been no attempt to systematically differentiate cry from non-cry vocalizations. Twelve exemplars each of cry, whine, and vowel-like sound segments (36 total) were selected from archival audio recordings of infant vocalizations. Categories were selected from expert-judged audio signals of vocal development. Adult listeners identified each utterance as either cry, whine, or vowel-like sound as quickly and accurately as possible. They also judged the extent of negativity of each utterance. Acoustic features of each utterance were analyzed in association with the categories and degrees of negativity. Results suggest a continuum of negativity from cries (most negative) to vowel-like sounds (least negative), and that acoustic variables are gradated across the negativity continuum. However, preliminary results suggest that peak F0, peak RMS, and spectral slope best differentiate the categories.
Amplitude-modulation detection and speech recognition in normal and hearing-impaired listeners
Authors: Verhulst Sarah , Warzybok Anna
Published: June 2017

Even though temporal speech envelopes may form a salient cue when listening to speech in noisy backgrounds, the relationship between speech intelligibility and the sensitivity to detecting temporal envelopes (i.e., amplitude modulation detection) is not well understood. This study measured speech reception thresholds in quiet, stationary and speech-modulated noise in three listener groups: young (yNH) and older normal-hearing (oNH) listeners and hearing-impaired (HI) listeners. In addition to broadband speech and noise signals, we adopted low and high-pass filtered versions of the stimuli to study the contribution of different coding mechanisms in basal and apical cochlear regions. For the same listeners, amplitude-modulation (AM) detection thresholds were measured in quiet and in the presence of broadband masking noise for 70 dB AM tones of 0.5, 2 and 4 kHz with either 100 or 5 Hz modulation frequency. Even though group trends were clearer than individual differences, AM detection thresholds showed a relationship to speech recognition in the low-pass filtered speech-modulated noise condition, and for yNH and oNH listeners in the high-pass filtered condition. Overall, this study sheds light on the importance of temporal envelope coding sensitivity for speech recognition and its relationship to near-and supra-threshold hearing deficits.
Capturing sound of target source located beyond noise source by line microphone array
Authors: Ando Akio , Yamauchi Kodai , Onishi Kazuyoshi
Published: June 2017

We had developed a method that captured the target sound when the noise source was located in front of the target source. It used a line microphone array whose direction was toward the noise source and created a spatial null sensitivity point at the noise source position. Our previous method, however, could reduce the noise only in a narrow area around the null point. To extend the noise reduction area, we developed a new method that creates some adjacent null points with more than two microphones. The experimental result showed that, if the target source was located 8 m distant from the microphone, the new method with three microphones could create a -20 dB noise reduction area whose center was 6 m distant from the microphone with a radius of 0.5 m, and captured the target sound without changing its timbre.
Model-error-compensated reiterative adaptive beamforming on a physically shaded cylindrical array
Authors: Botts Jonathan , Summers Jason E. , Gaumond Charles F.
Published: June 2017

The authors formulate and compare beamspace and element-space formulations of Reiterative Superresolution (RISR) [S. D. Blunt et al., IEEE Trans. Aero. & Elec. Sys. 47, 332-346 (2011)] on a physically shaded cylindrical array. The beamspace adaptive approach minimizes computational load while use of a model-based structured covariance estimates enables adaptive beamforming with Doppler sensitive waveforms having little sample support. While structured covariance estimates reduce sample-support requirements and facilitate stable inversion, they also introduce degradation due to model-mismatch errors. In space-time adaptive processing (STAP), covariance matrix tapers (CMT) have been used to counter the effects of off-axis arrivals and other forms of model mismatch [J. R. Guerci, Space-Time Adaptive Processing for Radar (Artech, 2014)]. In adaptive pulse compression, CMT have been used to increase range sidelobe suppression in the presence of Doppler [T. Cuprak, M.S. Thesis (2013)]. In this work, we have formulated CMT to address model mismatch by accounting for interbeam arrivals. We also consider the degree to which CMT can be used to address model-mismatch in RISR resulting from the physical shading effects on the directionality of elements in a large cylindrical array. [Portions of this material are based upon work supported by the Naval Sea Systems Command.]
Comparison of time domain noise source localization techniques: Application to impulsive noise of nail guns
Authors: Padois Thomas , Gaudreau Marc-André , Doutres Olivier , Sgard Franck C. , Berry Alain , Marcotte Pierre , Laville Frédéric
Published: June 2017

Microphone array techniques are an efficient tool to detect acoustic source positions. The standard technique is the delay and sum beamforming. In the time domain, the generalized cross correlation of the microphone signals is used to compute the Spatial Likelihood Functions (SLF) of all microphone pairs and the noise source map is provided by the arithmetic mean of these functions. To improve the former noise source map, which means narrowing the main lobe and removing side and spurious lobes, several techniques have been developed in the past. In this work, the performances of three of these techniques (in terms of source position detection, amplitude estimation and computation time) are compared in the case of both synthetic and real data: (1) energetic and geometric criteria are applied in order to remove the SLF with useless information, (2) the arithmetic mean is replaced by the generalized mean and (3) linear inverse problem is solved with sparsity constraint. In the case of real data, the source to be located and quantified is an impulsive noise radiated by nail guns which is recorded by a spiral arm microphone array.
The impact of naval requirements on sonar development
Authors: Bradley David L.
Published: June 2017

A “walk” through history from WWI to today provides an overview of sonar system evolution. The time and spatial constraints of Naval sonar systems are not necessarily consistent with those required for scientific studies of the ocean and its boundaries. The pressure from these competing purposes has resulted in major advances, but also compromises in sonar design and implementation. The circumstances of the Cold War led to complications in the relations between ocean scientists and undersea warfare specialists, in turn leading to competition for limited resources and consequent weak cooperation between the communities. The result was a slowing of the development pace of acoustic systems. More recently, re-convergence has occurred and improved, multi-purpose sonar systems are the norm.
The internal wave prediction component of the Integrated Ocean Dynamics and Acoustics Project
Authors: Duda Timothy F. , Lin Ying-Tsong , Lynch James , Newhall Arthur , Zhang Weifeng G. , Helfrich Karl R. , Lermusiaux Pierre F.
Published: June 2017

The accuracy of ocean sound propagation modeling depends on properly representing the environment. The water column portion of this has phenomena and features that are time- and space-dependent, covering a huge range of scales. Nonlinear internal gravity waves (nonlinear internal waves, NIW) in shallow areas are important features that are moving, evolving and anisotropic, and whose effects can be handled properly only with 3D sound modeling. Thus, 3D NIW field predictions would be needed for comprehensive modeling. One challenging part of our project to make acoustic condition forecasts from available data involves making this 3D NIW field prediction using data-assimilating regional models that do not faithfully handle NIW. Our methods for extracting internal tide signals from the models, analyzing their propagation into regions where they transform in reality to NIW (but not in the models), and predicting NIW conditions in these regions are explained here. Outstanding challenges such as how to parameterize internal-tide coupled mode propagation on slopes and how to model highly nonlinear crossing NIW groups will be presented. The question of what constitutes an effective NIW prediction for acoustic purposes will be addressed.
Demonstration of nonlinear tuning curve vibration of granular medium supported by a clamped circular elastic plate using a soil plate oscillator
Authors: Santos Emily V. , Korman Murray S.
Published: June 2017

A demonstration will be conducted in order to show how a soil plate oscillator (SPO) filled with granular material will create a nonlinear system due to shifting peaks in a tuning curve with incremental increases in the swept drive amplitude. An SPO has two flanges clamping an elastic plate which supports a circular column of granular material. The plate (with a magnet and accelerometer fastened to the underside) is driven below by an amplified swept sinusoidal current applied to an AC coil. Past results have used masonry sand, granular edible uncooked materials, and glass beads in order to study the nonlinear tuning curve response near a resonance with (1) a fixed soil column while changing drive amplitude and (2) mass loading of a soil column versus the resonant frequency response of the system at a fixed drive amplitude. When the experiments are performed at a fixed drive but with a changing mass layer the resonant frequency increases then decreases with increased added mass due to an increase in flexural rigidity of the granular media disk layer which dominates the effect of adding mass. SPO tuning curves resemble the nonlinear mesoscopic elastic behavior of resonant effects of geomaterials such as sandstone.
Encomium for Hugo Fastl
Authors: Vorlaender Michael , Schulte-Fortkamp Brigitte
Published: June 2017

EAA AWARD for Lifetime Achievements in Acoustics
A generalized version of the Lubman-Kiser theory of historical acoustics and worship spaces
Authors: Boren Braxton B.
Published: June 2017

Although some relationship between liturgy, theology, and acoustics has been inferred by architectural acousticians at least since Hope Bagenal, this phenomenon has best been cataloged in a brief paper by Lubman and Kiser (ICA, 2001). Although all historical theories are difficult to distill in a single sentence, it might be briefly summed up as the statement that all things being equal, a change in acoustical conditions will result in a change in liturgy, and a change in theology will result in a change in acoustical conditions. This is usually described along a one-dimensional continuum between greater clarity or greater reverberance, and Lubman and Kiser describe much of this motion along this continuum throughout the history of the Western church through the Protestant Reformation and up to the present day. An attempt is made to generalize this theory and to examine whether the Western acoustical progression is mirrored in the historical experiences of other religious traditions and cultures.
The acoustics of the catacombs of Vigna Cassia in Syracuse
Authors: Lombardi Ilaria , Trematerra Amelia
Published: June 2017

The aim of this study is the evaluation of acoustic characteristics of the burial place in particular the Vigna Cassia’s catacombs in Syracuse. In late antiquity (III—VI cent. A.D. ), the catacombs were the burial places of the Christian communities, but they were also places for prayer and sacred functions, celebrated especially for the presence of the tombs of the martyrs. The study of the acoustics of the catacombs was performed with the technique of the impulse response, some firecrackers were detonated in different areas of the catacombs and the answers were realized in function of the monaural parameters STI, T30, EDT, C80, and D50. The acoustic study was performed to define whether in such places, with complex geometries and interconnected tunnels, there are favorable conditions for speech understanding and for meditation and prayer.
Room acoustics and the organbuilding of two great Boston pipe organs
Authors: Cuff Nicole , Russell Daniel A.
Published: June 2017

Pipe organs are like giant snowflakes: each one perfectly distinct and a marvel of craftsmanship, creativity, and design. This presentation will compare how master organbuilders designed their organs to complement different room acoustics. The first is one of the largest pipe organs in the world at the Christian Science Church Extension Building in Boston, Massachusetts, built in 1952 by Lawrence Phelps, and the other is the Cathedral of the Holy Cross in Boston, built in 1875 by Elias and George Greenleaf Hook, known as their most innovative and elaborate organ at the time of construction. How did the master organbuilders work with two rooms with varied reverberation times, nearly a century apart? Why did these master organbuilders construct particular organ stops in the ways that they did? How do their works compare to organ design standards? What is the resulting sound in the rooms? For local Bostonians, there will be organ concerts at the Christian Science Church June 13, 2017 from 12:15 to 12:45 pm and August 8, 2017 from 12:15 to 12:45 pm.
Experimental investigations on a light-weight aerogel layer in gypsum wallboards for increased sound transmission loss
Authors: Xiang Ning , Whitney Mathew A. , Lu Hongbin , Leventis Nicholas
Published: June 2017

It has long been considered challenging to increase sound transmission loss of gypsum wallboards without significantly increasing the board thickness and weight. Low-density highly porous solid monolithic macroscopic objects consisting of hierarchical mesoporous three-dimensional assemblies of nanoparticles (aerogels) are pursued mainly for their low thermal conductivity. Unlike classical aerogels of the most common kind based on silica being fragile materials, structural fragility issue has been addressed successfully with materials referred to as polymer-crosslinked (or X-) aerogels. X-aerogels are very low-density materials, yet their mechanical strengths have been significantly increased. This work explores ductile aerogels in potential uses as constrained damping layers integrated into gypsum wallboards. Due to their ductility and mechanical strength, light weight X-aerogel panels of less than 1 cm in thickness can be conveniently integrated into gypsum wallboards. The objective of this work is to develop integrated wallboards to achieve significantly increased sound transmission loss without significantly increasing thickness and weight of integrated wallboard system. This paper discusses preliminary test results carried out in chamber-based random-incident measurements, and further exploration on broadband dynamic properties of X-aerogels for better understanding of its excellent effect in drastically increased sound transmission loss.
Noise reduction research of high-speed railway U-shaped beam
Authors: Guo Jing , Yan xiang
Published: June 2017

Railway noise has become an important factor restricting the further development of railway and endangering human health. Because of the particularity of the structure of the railway bridge, the noise radiation source is strong, the noise varies with the distance and the noise reduction effect of the sound barrier is different from that of the railway section. Therefore, how to effectively control the impact of railway noise on residents on both sides of the bridge section has become the focus of environmental protection workers, research the influence of noise of railway bridge segment noise in residential area along the railway is very important. In the acoustic test program of high-speed railway u-shaped beam, we will select the most appropriate noise reduction scheme through the computer simulation and model test of HSR u-shaped beam with different structural forms of test, and provide reliable reference for practical engineering.
Comparison of frequency responses calculated across different time-windowed impulse responses for assorted types of rooms
Authors: Boyd Brenna N. , Wang Lily M.
Published: June 2017

Recent work by Lokki et al. (2015) has shown that analyzing how frequency responses from concert halls change over different time-windowed periods of the impulse response across low, mid, and high frequencies correlates well with human perception of how well the space performs. In this project, such frequency response analyses across different time-windowed impulse responses are applied to spaces other than concert halls to include a variety of classrooms, worship spaces, and speech-centered performance spaces. Preliminary results from the study will be presented, with particular focus on comparing spaces designed primarily for speech, music, or both.
Co-integration of acoustic simulation software and GIS for speech intelligibility analysis in complex multi-source acoustic environments. Application to Toledo's Cathedral
Authors: Pedrero Antonio , Iglesias Luis , Ruiz Rogelio , Díaz César
Published: June 2017

The speech intelligibility in complex multi-source acoustic environments depends on a variety of factors such as speech level, background noise level, reverberation time, as well as psychoacoustic effects. Since these factors can change for each source-receiver combination, in order to integrate information from various sources, efficient tools and techniques are required to determine the speech intelligibility at every listener position. In drawing up this study, two types of tools are used: (i) an acoustic simulation software (ODEON) and (ii) spatial analysis tools of a Geographic Information System (ArcGIS). To determine the speech intelligibility, the Speech Transmission Index (STI) has been calculated. Sound Pressure Level and Reverberation Time have been calculated at points of a grid at intervals of 1 meter. An automated workflow using ArcGis Modelbuilder has been created in order to obtain STI. Also, Arcmap has been used to represent and analyze the results over the complex geometry of the space. The proposed procedure has been calibrated using information obtained in the Toledo Cathedral (Spain) and the results for acoustic situations related to different celebrations of the liturgy are presented.
A parametric model for the synthesis of binaural room impulse responses
Authors: Stade Philipp , Arend Johannes M. , Pörschmann Christoph
Published: June 2017

Binaural room impulse responses (BRIRs) are often applied in spatial audio for the auralization of acoustical environments. In the same field of research, parametric audio coding is an established approach and part of different standards. The presented investigation aims for a parametric description of the sound field in order to synthesize BRIRs for a plausible auralization. The model focuses on the main features which characterize a BRIR as well as the acoustical environment. Thereto spherical microphone arrays are applied for a spatio-temporal acoustical analysis using spherical harmonics. Early reflections are determined with sound field decomposition techniques and are described by directional parameters. Diffuse components and the interaural coherence of the late reverberation are characterized with additionally parameters. In two previous studies, the synthesis of the early and the late part of BRIRs have been elaborated and perceptually evaluated apart from each other. Now both approaches are combined to synthesize entire BRIR datasets using the parametric approach. Fundamentals of the sound field analysis are explained and synthetic BRIRs are compared to their measured counterparts.
Comparative analysis of absorption coefficients’ effect on room acoustic parameters determined by simulation software
Authors: Murray Gabriel , Aspöck Lukas , Vorlaender Michael
Published: June 2017

A comparative analysis between different sets of absorption coefficients, found or calculated from a variety of sources and methods, including traditional databases and newer in-situ methods, was carried out. This analysis utilized different architectural acoustic simulation software packages for verification of results and further comparison. Initially, a shoebox model was compared for reference and brief comparison between the software packages was made. Then, the main analysis was conducted using the model of the RWTH Aachen Institute of Technical Acoustics’ Seminar Room. This room was simulated with all the different sets of absorption coefficients through both simulation software packages. The purpose of this analysis was to provide a reference for the variation of room acoustic parameters from the different sources of absorption coefficients.
Evaluation of higher order sound particle diffraction with measurements around finite sized screens in a semi-anechoic chamber
Authors: Weigand Stefan , Aspöck Lukas , Stephenson Uwe M.
Published: June 2017

Noise prediction and room acoustic design rely on simulation methods to model sound propagation. The sound particle simulation method (SPSM), among others, is an increasingly popular choice to do so. In recent years, the combination with the uncertainty based diffraction (UBD), where particles are deflected according to edge bypass distances measured in wavelengths, has helped to overcome typical high frequency limitations. To evaluate SPSM with UBD, 3D simulations are compared to measurements in full scale. As previous attempts to evaluate in real rooms suffered from difficulties to acquire accurate material coefficients, measurements are conducted in a controlled environment. A semi-anechoic chamber allows to examine free-field conditions as well as combinations with floor and wall reflections. This paper focuses on diffraction measurements around one or multiple screens of finite size. This allows the examination of higher order diffraction in combination with reflections. Impulse responses are measured for several receivers around screens. From these impulse responses, acoustical parameters are calculated and compared to SPSM results.
Investigating energy integration time limits for listener envelopment perception using a real-time adaptable hybrid impulse response method
Authors: Savage Evan M. , Neal Matthew T. , Vigeant Michelle C.
Published: June 2017

Listener envelopment (LEV), the sense of being immersed in a sound field, is a common perception in concert hall acoustics, but more work is needed to establish a metric. The objective of this research is to further investigate LEV utilizing custom software building on Dick & Vigeant’s previous research to understand what contributes most to LEV in a concert hall (JASA 140:3175 2016). For this study, spatial room impulse response (SRIR) measurements were obtained using a 32-channel spherical microphone array in different performance venues. These SRIRs were used in a subjective listening test and processed for 3rd order Ambisonic reproduction over a 30-loudspeaker array. Utilizing a custom testing interface developed in Max 7, pairs of equal-length SRIRs with contrasting high and low LEV were time-windowed and summed together to create a hybrid SRIR. A dial in the interface controlled the hybrid SRIR’s time transition point, and subjects were asked to adjust the timing dial to the point at which they perceived the highest sense of LEV. Results will be presented showing the integration limits that produced noticeable changes in LEV and implications to the proposed LEV metric will be discussed. [Work was supported by NSF Award 1302741.]
Enjoying the performing arts with hearing loss: Challenges, options, and a look to the future
Authors: Recker Karrie
Published: June 2017

The presence of hearing loss can severely limit an individual’s enjoyment of the performing arts by making soft sounds inaudible and by distorting sounds that are supra-threshold. Because hearing loss is correlated with aging, it often co-occurs with other impairments such as vision loss and cognitive decline. Hearing aids and other assistive technologies can help, but they have limitations. This talk will provide an overview of the most common type of hearing loss experienced by an aging population, explore the difficulties faced by these individuals, summarize the current strategies for improving their listening experiences in these venues, and touch on emerging research in this field.
The evidence and new technology of hearing loops
Authors: Thunder Steve , Thunder Thomas
Published: June 2017

In the last several years, the evidence has been growing to support a stronger adoption of hearing loops to overcome adverse room acoustics. We will explore various research and how it relates to the listening experience of people with hearing loss. Including how new technology has been included to further improve the user and installer experience. Also, will future technologies replace hearing loops and other traditional assistive listening? Come find out. Steve Thunder has a financial relationship to Listen Technologies, a manufacturer/distributor of assistive listening equipment. Tom Thunder has a financial relationship to Assistive Hearing Systems, a firm specializing in the installation of hearing loops.
Simulation of acoustic environments for binaural reproduction using a combination of geometrical acoustics and Boundary Element Method
Authors: Hargreaves Jonathan A. , Rendell Luke , Lam Yiu W.
Published: June 2017

Auralization of a space requires measured or simulated data covering the full audible frequency spectrum. For numerical simulation, this is extremely challenging, since that bandwidth covers many octaves in which the wavelength changes from being large with respect to features of the space to being comparatively much smaller. Hence, the most efficient way of describing acoustic propagation changes from wave descriptions at low frequencies to geometric ray and sound-beam energy descriptions at high frequencies. These differences are reflected in the disparate classes of algorithms that are applied. Geometric propagation assumptions yield efficient algorithms, but the maximum accuracy they can achieve is limited at low frequencies in particular. Methods that directly model wave effects are more accurate but have a computational cost that scales with problem size and frequency, thereby limiting them to small or low frequency scenarios. Hence, it is often necessary to operate two algorithms in parallel to handle the complete bandwidth. Here, we utilize Boundary Element Method as the low frequency method in such a scheme. Using the SEACEN Round Robin scenarios as case studies, this paper will discuss challenges including: representing source directivity; choosing suitable boundary condition data; encoding BEM results for binaural presentation.
Finite volume method room acoustic simulations integrated into the architectural design process
Authors: Pind Finnur , Jeong Cheol Ho , Engsig-Karup Allan P. , Strømann-Andersen Jakob
Published: June 2017

In many cases, room acoustics are neglected during the early stage of building design. This can result in serious acoustical problems that could have been easily avoided and can be difficult or expensive to remedy at later stages. Ideally, the room acoustic design should interact with the architectural design from the earliest design stage, as a part of a holistic design process. A new procedure to integrate room acoustics into architectural design is being developed in a Ph.D. project, with the aim of promoting this early stage holistic design process. This project aims to develop a new hybrid simulation tool combining wave-based and geometrical acoustics methods. One of the important aspects is the flexibility to represent realistic geometric shapes, for which the finite volume method (FVM) is chosen for the wave-based part of the tool. As a starting point, the computational efficiency of high-order two-dimensional FVM for defining an efficient wave-based simulation tool is investigated. Preliminary two-dimensional FVM simulation results are presented, which illuminate the suitability for handling complex geometries compared to other wave based simulation methods.
Evaluating simulations of acoustic environments by learning time-frequency kernels that optimally separate classes of simulated signals
Authors: Summers Jason E. , Botts Jonathan , Gaumond Charles F.
Published: June 2017

Previously, the authors have presented techniques for classifying the aural accuracy of computed impulse responses for room-acoustic simulation and for sonar-operator training using two-dimensional distance metrics operating on time-frequency representations (TFRs) calculated using computational auditory models and by a generalized TFR formed by an affine radial-Gaussian correlation kernel operating on the Wigner-Ville distribution (i.e., Cohen’s class), with kernel parameters optimized for binary classification [J. E. Summers et al., J. Acoust. Soc. Am. 115, 2514 (A) (2004); J. E. Summers et al., Proc. 19th Int. Cong. Acoust., 8, 4591-4596, RBA-05-015-IP (2007)]. Here, we revisit the use of classification-optimized TFR for distinguishing between measured and simulated impulse responses and between impulse responses simulated by different computational approaches in the domains of room-acoustics and submerged target scattering. The learned parameters of the optimized TFR kernels are investigated with respect to the information they provide about the nature of the differences between impulse-response classes, particularly as they indicate temporal and spectral scales of those phenomena that particular computational models fail to represent. [Work supported by ARiA IR&D and the Office of Naval Research.]
Estimating the diffuseness of sound fields: A wavenumber analysis method
Authors: Nolan Mélanie , Davy John L. , Brunskog Jonas
Published: June 2017

The concept of a diffuse sound field is widely used in the analysis of sound in enclosures. The diffuse sound field is generally described as composed of plane waves with random phases, which wave number vectors are uniformly distributed over all angles of incidence. In this study, an interpretation in the spatial frequency domain is discussed, with the prospect of evaluating the diffuse field conditions in non-anechoic enclosures. This work examines how theoretical considerations compare with experimental results obtained in rooms with various diffuse field conditions. In addition, the paper investigates how the results relate to the modal theory of room acoustics, based on the conception that any mode, also in non-rectangular rooms, can be expanded into a number of propagating waves.
Exploring the physical theory of diffraction for solutions of wedge fields in room-acoustic simulation
Authors: Xiang Ning , Rozynova Aleksandra
Published: June 2017

The need of developing accurate and cost-effective room-acoustic simulations has prompted recent investigations on edge diffractions with some progresses on solving multiple-order diffractions of finite wedges. This work explores an alternative approach based on the physical theory of diffraction [P. Ya. Ufimtsev, J. Acoust. Soc. Am. 120, 631-635 (2006)] which is well suited for solving acoustic scattering problems from reflecting objects for room-simulation purposes. Although the approaches based on the principle of geometrical acoustics (GA) are widely applied, they are less suitable for geometrical shadow boundaries. The physical theory of diffraction still relies on both geometrical and physical principles, yet emphasizes the physical one. One of the important features of this physical acoustics (PA) approach is the ability to calculate the sound field more accurately in shadow boundaries. To this end, exact and asymptotic solutions of wedge fields are discussed for secondary edge sources induced by the incident wave. This paper will discuss implemented results of several canonical cases with emphasis on Neumann boundary condition.
Secondary surface sources at rigid wedges based on the physical theory of diffraction
Authors: Rozynova Aleksandra M. , Xiang Ning
Published: June 2017

In the context of room-acoustic simulations, diffractions on obstacles with edges still post challenges. In order to create an efficient and accurate room acoustic simulation, this work focuses on solutions of diffraction on finite wedges. The solutions are based on the physical theory of diffraction [P. Ya. Ufimtsev, J. Acoust. Soc. Am. 120, 631-635 (2006)]. A detailed discussion on integral and asymptotic expressions for the diffracted field radiated by secondary wedge sources will help elaborate problem-solving strategies with the grazing incidence for exact and asymptotic solutions of wedge fields. Due to the fact that the computational load of an asymptotic solution is of orders of magnitude more efficient than that of the exact solution using the physical diffraction theory, any possible ways of reducing asymptotic errors without significantly increasing computational load will be critically important in practical room-simulations. This paper will discuss implementation based on the physical theory of diffraction. For some canonical wedge configurations, this paper will also elaborate on asymptotic errors as a function of incident source distance and direction.
Experimental investigations on two potential sound diffuseness measures in enclosures
Authors: BAI XIN , Herder John , Xiang Ning
Published: June 2017

This study investigates two different approaches to measure sound field diffuseness in enclosures from monophonic room impulse responses. One approach quantifies sound field diffuseness in enclosures by calculating the kurtosis of the pressure samples of room impulse responses. Kurtosis is a statistical measure that is known to describe the peakedness or tailedness of the distribution of a set of data. High kurtosis indicates low diffuseness of the sound field of interest. The other one relies on multifractal detrended fluctuation analysis which is a way to evaluate the statistical self-affinity of a signal to measure diffuseness. To test these two approaches, room impulse responses are obtained under varied room-acoustic “diffuseness” configurations, achieved by using varied degrees of diffusely reflecting interior surfaces. This paper will analyze experimentally measured monophonic room impulse responses, and discuss results from these two approaches.
Anthony Hawkins—A pioneer of fish bioacoustics
Authors: Sisneros Joseph A.
Published: June 2017

For over 50 years since his first description of underwater sounds by the haddock (Melanogrammus aeglefinus), Anthony (Tony) Hawkins has investigated numerous topics on fish bioacoustics and has been a leading pioneer in examining the production and reception of sound by fishes and more recently the impacts of anthropogenic sounds on fishes. Tony has worked on a diverse number of fish species including commercially important species such as the cod (Gadus morhua) and the Atlantic salmon (Salmo salar). He has investigated a number of important bioacoustic research topics that range from investigating the acoustic properties of swim bladders, examining how behaviorally-relevant sounds can be masked by sea noise, and determining the directional hearing sensitivities and capabilities of fishes. Throughout his career, Tony has strived to perform behavioral experiments on fish under the appropriate biologically relevant acoustic conditions in the natural environment, which can often be a more difficult but an effective and rewarding approach to conducting fish bioacoustic experiments. His classic experiments and important research findings on fish hearing are still referenced today and are regularly used in environmental impacts statements to estimate the hearing capabilities of fishes.
Effect of environmental toxins on the fish lateral line
Authors: Coffin Allison
Published: June 2017

Fishes use their lateral line system to sense nearfield water movement associated with both abiotic and biotic sources. Given the external location of lateral line sensory organs, we hypothesized that this system would be sensitive to exposure from toxins that accumulate in the aquatic environment. The toxicant bisphenol-A (BPA), a component of many plastics, is prevalent in U.S. watersheds. We found that BPA exposure did not influence lateral line development in zebrafish, but that BPA was toxic when applied acutely to mature lateral line organs. BPA also reduced the regenerative potential of the lateral line, suggesting that BPA may affect both sensory hair cells and surrounding supporting cells. As fish in urban areas are often exposed to high levels of road pollution that enters waterways during storm events, we also examined the effect of stormwater runoff on the lateral line. In contrast to BPA, stormwater was not acutely toxic to the mature lateral line, but it had a detrimental effect on lateral line development in both zebrafish and salmonids. Collectively, our results demonstrate that aquatic pollutants can negatively impact fish mechanosensory systems, perhaps leading to decreased survival.
A personal history of fish bioacoustics
Authors: Popper Arthur N. , Hawkins Anthony D.
Published: June 2017

Together, we represent more than 100 years of research on various aspects of fish bioacoustics, starting with basic work on hearing, and continuing today in our individual and joint work on effects of man-made sound on aquatic animals. Over the course of our careers, we have had the honor of knowing, and in some cases working with, many of the true pioneers in our field—people whose contributions were fundamental to fish bioacoustics, and whose work should be read and known by everyone who is pursuing marine bioacoustics now and those who enter the field in the future. During the course of this talk we will briefly mention the contributions of notables one or both of us has personally known including (in alphabetical order): John Blaxter, Horst Bleckmann, Rob Buwalda, Colin Chapman, Sheryl Coombs, Eric Denton, Sven Dijkgraaf, Andreas Elepfandt, Per Enger, Richard Fay John Gray, Donald Griffin, Gerard Harris, Kathleen Horner, Cathy McCormick, James Moulton, Arthur A. Myrberg Jr., Antares Parvulescu, Christopher Platt, Olav Sand, Arie Schuijf, William Tavolga, and Willem van Bergeijk. We dedicate this presentation to our close friend and collaborator, and one of the great pioneers of studies of fish hearing, Richard R. Fay.
Edwin L. Carstensen, A scientist’s life
Authors: Blackstock David T.
Published: June 2017

Born in 1919, Edwin L. Carstensen grew up in Oakdale, Nebraska. Thinking to be a teacher or preacher, Ed attended Nebraska State Teachers College, 1938-1941. An interest in physics and music led Ed in fall 1941 to Case School of Applied Science. But World War II interrupted; when his professor Robert Shankland was tapped to head the newly formed Underwater Sound Reference Laboratory in spring 1941, Ed followed and spent the war and early postwar years at USRL’s lab in Orlando, Florida. Thus Ed’s first serious involvement in acoustics was in underwater sound. Several publications emerged after the war; the most significant was the Carstensen-Foldy study of sound propagation through bubbly water (JASA 19, 481-501 (1947)). After PhD studies at University of Pennsylvania, 1948-55, where Herman Schwann introduced Ed to biophysics, and five years at the Army Biological Laboratory, Ft. Detrich, Maryland, Ed took a faculty position in Electrical Engineering at the University of Rochester. There he remained for the rest of his career. His work at Rochester was in biomedical acoustics, principally biomedical ultrasound. He made major contributions to identifying the physical mechanisms by which ultrasound affects tissue, lithotripsy, and tissue strain as an ultrasound bioeffect.
Edwin L. Carstensen, the father
Authors: Carstensen Laura L.
Published: June 2017

Edwin Lorenz Carstensen was son to Opal and August, husband to Pam, father to five, grandfather to seven, and great-grandfather to two. Each and every one of us, along with many more extended family members, feel extraordinarily privileged to be associated with him. We fully appreciate that Ed Carstensen was a giant in his scientific discipline. Know also that he achieved all that he did while showing unfailing grace and full dedication to a devoted, and challenging, family. In the relatively short time since he died, we have learned about scores of qualities you admired in the scientist. In this talk, I hope to share with you the many similarities between the scientist and the father. He was invariably kind and gently critical in ways that clarified our thinking. He was insatiably curious about everything in which we showed an interest, and he encouraged us to be better people simply by believing that we were. I asked him once how he possibly managed to accomplish all that he had professionally with five children running around the house. He smiled and said, “Oh, about 50 papers never made it out the door.” We’ll need to count on you all for those.
Ed Carstensen and the recognition of nonlinear acoustics in biomedical ultrasound
Authors: Muir Thomas G.
Published: June 2017

Nonlinear acoustics in biomedical ultrasound was not well recognized, nor utilized in the era leading up to the 1980s. The discipline was experiencing rapid growth and experimentation, but without consideration of nonlinear effects, even though they were significant. Ed Carstensen was one of the first to become suspicious of the “linear assumption,” mostly in his own experiments. In 1979, he contacted me and asked for help in making the community aware of nonlinear acoustics at biomedical frequencies and intensities. The two of us, with the help of David Blackstock and Ed’s graduate students, W.K. Law and N.D. McKay, set out to produce a pair of tutorial manuscripts, to call the community’s attention to acoustic nonlinearity. These were published in the Journal of Ultrasound in Medicine and Biology, Vol. 6, p 345-357, and 359-368 (1980). The first was a description of pertinent nonlinear acoustic theory, as then used, and the second was an experimental demonstration of nonlinear effects, easily recognizable in the laboratory. The present paper recounts the situation at the time (37 years ago) which experienced a turning point, once nonlinear acoustics was recognized. Existing perplexities were resolved and new paths of research and development were identified. Some discussion of here-to-fore unappreciated individuals and history in nonlinear acoustics is also presented. [Work supported by Applied Research Laboratories, The University of Texas at Austin.]