bluuebunny/crossref_metadata_2025 huggingface dataset:
Artillery location: Battlefield acoustics in the First World War
Authors: Costley R. D.
Published: April 2019

Although acoustics has played a role in warfare for hundreds, if not thousands, of years, the First World War came after the technological advances of the late 19th and early 20th centuries that enabled more quantifiable and less subjective observations. In 1914, after the outbreak of the war, Frenchman Charles Nordmann, a Professor of Astronomy at the Paris Observatory at Meudon, conceived and developed systems for locating artillery by measuring the differences in the times of arrival of the sound from the artillery to different observation positions. In one system, humans made “subjective” observations; alternatively, an “objective” system recorded these sounds with carbon microphones. In July 1915, Colonel Coote Hedley, head of the Geographical Section of the General Staff in London, learned of Nordmann’s work on a visit to France and recruited Second Lieutenant William Lawrence Bragg to evaluate it. Bragg led the allied effort to improve and deploy sound-ranging systems. In developing the system, they encountered problems in sensor design, array design, wind noise, and outdoor sound propagation. The technical achievements gained and obstacles encountered will be described, along with the impact they made to the war effort. Permission to publish was granted by Director, Geotechnical and Structures Laboratory.
Broadband acoustic vector sensing in a forested environment
Authors: Collier Sandra L. , Denis Max , Noble John , Solomon Latasha , Ligon David , James Deryck D. , Alberts W. C. Kirkpatrick , Reiff Christian G. , Sim Leng
Published: April 2019

The horizontal acoustic particle velocity and acoustic pressure, concurrent with atmospheric data, were collected during a series of outdoor field tests. Here, we present the effects of a forested environment on acoustic vector sensing for broadband sources. The sources are representative of battlefield signals of interest. The complex distributions are studied in the unsaturated, partially saturated, and fully saturated regimes. Distinct path-dependent, frequency-dependent propagation effects are observed.
The role of cue enhancement and frequency fine-tuning in hearing impaired phone recognition
Authors: Abavisani Ali , Allen Jont
Published: April 2019

A speech-based hearing test is designed to identify the susceptible error-prone phones for individual hearing impaired (HI) ear. Only robust tokens in the experiments' noise levels had been chosen for the test. The noise-robustness of tokens is measured as SNR90s of the token, which is the signal to the speech-weighted noise ratio where an NH listener would recognize the token with an accuracy of 90% on average. Two sets of tokens T1 and T2 having the same consonant-vowels but different talkers with distinct SNR90s had been presented at flat gain at listeners' most comfortable level. We studied the effects of frequency fine-tuning of the primary cue by presenting tokens of the same consonant but different vowels with similar SNR90s. Additionally, we investigated the role of changing the intensity of primary cue in HI phone recognition, by presenting tokens from both sets T1 and T2. On average, 85% of tokens are improved when we replaced the CV with the same CV but with a more robust talker. Additionally, using CVs with similar SNR90, on average, tokens are improved by 28%, 28%, 25%, and 19%, when we replaced the vowel with ɑ, ɛ, ə, and ɪ. The confusion pattern in each case provides insight into how these changes affect the phone recognition in each HI ear. We propose to prescribe hearing aid amplification tailored to individual HI ears, based on the confusion pattern, the response from cue enhancement, and the response from frequency fine-tuning of the cue.
Physiological assays of suprathreshold hearing are consistent with widespread deafferentation of the human auditory periphery
Authors: Mai Alexandra , Flesher Brooke , Dougherty Kelsey , Hagedorn Anna , Simpson Jennifer M. , Heinz Michael G. , Bharadwaj Hari M.
Published: April 2019

Multiple animal models have robustly shown the effects of noise-exposure and aging can have on the afferent synapses between the cochlea and the auditory nerve. This cochlear synaptopathy can affect responses to suprathreshold stimuli while leaving audiometric thresholds intact. However, currently, there is much debate on whether these same changes occur in humans with significant noise-exposure or with middle age. Our study examined two different physiological responses in which these afferent synapses are a crucial component, the auditory brainstem response (ABR) and the middle ear muscle reflex (MEMR). Versions of these measures were completed in both a clinical setting and a laboratory. Responses to both measures in both testing environments demonstrated significant age and noise-exposure effects. Moreover, these effects remained significant even after statistically accounting for variability in audiometric sensitivity and otoacoustic emissions, suggesting that despite clinically normal audiograms, cochlear synaptopathy may be a widespread occurrence in humans with both acoustic-overexposure and normal aging. Finally, our results suggest that a battery combining ABR and MEMR measures may be viable as a non-invasive assay of synaptopathy and can help examine the perceptual sequelae of such damage.
Design and additive manufacturing of electro-mechanical metamaterials with designed anisotropy and self-sensing
Authors: Zheng Xiaoyu (Rayne)
Published: April 2019

In this talk, I will present our research on design, additive manufacturing, and performances of new classes of multi-functional materials that transcend the common electro-mechanical coupling limitations. These materials are as light as carbon aerogels, but with orders of magnitude higher stiffness and strength, they possess multi-functionalities. They are composed of interconnected 3D hierarchical micro-structures as designed “atoms” and “molecules” as in natural materials to reach uncharted white space in the material selection charts. Attention is focused on our development of a suite of novel additive manufacturing and processing techniques to synthesis traditionally unprocessable inorganic/organic highly responsive building blocks and architect them into scalable form factors with precisely defined active three-dimensional micro- and nano-scale features. We will discuss the possiblities of coupling and decoupling of the piezoelectric coefficients, density stiffness scaling, and selective electro-mechanical amplifications through our metamaterial design and printing approach. These insights shed light on a next generation of metamaterials, with designed-in structural and smart functionalities, including self-sensing and actuation, vector sensing and detection as well as simultaneous impact wave absorptions and self-monitoring with only a fraction of solid, as opposed to relying on multiple components.
Experimental observation of valley-Hall edge states in elastic waveguides based on diatomic-graphene-like phononic crystals
Authors: Zhu Hongfei , Liu Ting-Wei , Semperlotti Fabio
Published: April 2019

Inspired by recent discoveries of topological phases of matter in quantum physics, there has been a rapidly growing research effort in creating their analogs in other classical wave systems, including acoustics. Achieving robust wave transmission even in the presence of disorder and defects could have a profound impact on many practical applications and devices. In this study, we report on the design and experimental validation of a fully continuous and load-bearing phononic structural waveguide capable of one-directional guided modes along the walls of topologically distinct domains. The lattice structure of the waveguide is inspired by diatomic graphene which allows realizing an elastodynamic analog of the quantum valley Hall effect (QVHE). Despite the fact that individual bulk properties are topologically trivial (i.e., associated with a zero Chern number), the dynamic behavior acquires topological significance in the neighborhood of the high symmetry points in momentum space; the so-called valleys. Our theoretical and experimental results confirm the existence of protected edge states traveling along the walls of domains having broken space inversion symmetry.
Using ambient noise to evaluate the acoustic Green’s function for a passive geoacoustic inversion in a dynamic shallow-water environment
Authors: Tan Tsu Wei , Godin Oleg A. , Katsnelson Boris , Yarina Marina
Published: April 2019

Cross-correlation functions (CCFs) of ambient and shipping noise recorded by two hydrophones approximate the deterministic Green’s function and contain information about the propagation environment. This paper employs the data collected in the Shallow Water 2006 experiment on the New Jersey continental shelf to investigate the factors that affect the emergence of approximate Green’s functions from noise CCF estimates and accuracy of the approximation. One month-long continuous records of noise obtained by moored single-hydrophone receivers are analyzed. Hydrophones are located in 80–100-m deep water at distances of several kilometers from each other. Rapid variations of the water sound speed profile, which are primarily due to propagation of trains of strong nonlinear internal gravity waves, limit useful noise-averaging time. Available water temperature data are used to guide the selection of time windows for noise averaging and improve CCF evaluation and retrieval of information on seafloor properties. Various approaches to coherent stacking of CCFs are compared. Time warping transform is applied to the resultant noise CCF to extract dispersion curves of acoustic normal modes. The results of the geoacoustic inversion based on the passively measured dispersion curves are compared with the earlier results obtained using controlled sound sources. [Work supported by NSF and BSF.]
Implementation of random forest in geo-acoustic study
Authors: Hou Zhengyu
Published: April 2019

The correlation between sediment sound velocity (V) and physical properties has been studied for 60 years using empirical formulas and found to be difficult to predict V accurately. Random forest (RF) is a scientific discipline and a method of data analysis that automates analytical model building. Here, we present the implementation of the RF algorithm in V prediction and sediment classification. The goal of this study is to establish a predictive model based on RF using multiple physical parameters (mean grain size, porosity, wet bulk density, and water content). Compared to empirical formulas, the average error of RF velocity is only 0.95%, ranging from 0.03% to 2.73%, which has improved the accuracy of V prediction. We also used Mean Decrease Impurity importance to evaluate the importance of a variable and found that the most important feature in the predictive model is the mean grain size. The classification model based on RF reaching up to 75% accuracy in the dataset. Multiple features, such as physical properties, sedimentary environment, and sediment source, affect the geo-acoustic properties of sediments. The next goal is to use multiple features to improve the model and further improve the accuracy of sound velocity prediction and sediment classification.
The contribution of 12 kHz multibeam sonar to a southern California marine soundscape
Authors: Kates Varghese Hilary , Smith Michael J. , Miksis-Olds Jennifer L. , Mayer Larry
Published: April 2019

An ocean mapping survey was conducted over the Southern California Antisubmarine Warfare Range, a hydrophone range to characterize the radiation pattern of the R/V Sally Ride’s EM 122 (12 kHz) Kongsberg multibeam echosounder. Spanning a 2000 km2 area, the 89-hydrophones in the range, combined with the mapping survey, provided the opportunity to study the contribution of this anthropogenic noise to the marine soundscape. The soundscape was characterized and compared at selected hydrophones across the range before, during, and after the multibeam survey. One minute averages of the sound level were calculated over the data collection period. Sound level percentiles (P1, P10, P50, P90, and P99) were calculated for the full spectrum (1 Hz–48 kHz) and select frequency bands, and spectral probability density plots were generated for each time period. Frequency correlation matrices for each time period were produced and compared using difference matrices to identify changes in the soundscape. The results are placed in the context of the auditory scene of Cuvier’s beaked whales resident on the range by applying a mid-frequency marine mammal weighting function. [Work supported by NOAA, ONR, and Scripps Institute of Oceanography.]
Estimation of shipping noise from sparse measurements via generative adversarial networks
Authors: Chen Johnny L. , Summers Jason E.
Published: April 2019

There is growing interest in prediction of anthropogenic noise levels in the ocean. Evidence suggests that sources of ambient noise such as shipping traffic may be destructive to marine organisms that rely on acoustics for communication. Characterizing and predicting ambient noise are also critical to effective naval operations. Understanding ocean noise is constrained by the limited ability to directly measure the spatial distribution of noise levels. In this work, we present a deep-learning method to estimate the spatial distribution of ambient noise due to shipping from a small number of measurements. Noise levels are typically estimated using forward models based on statistical information about shipping routes and source levels and predictions or measurements of environmental variables including bathymetry and sound-speed profile. Inverse methods are sometimes used to estimate input parameters from in situ data. In contrast, we demonstrate the robust estimation of shipping noise using a pretrained generative adversarial network (GAN) as a prior. By using a context and prior loss, our algorithm is able to accurately predict the entire spatial distribution of noise from sparsely sampled measurements. This can yield greater accuracy than a forward model based on environmental parameters taken from archival databases or inferred in situ.
Machine learning assisted evaluation of interstitial lung diseases
Authors: Koo Chi Wan
Published: April 2019

Interstitial lung disease (ILD) is an inflammatory condition encompassing greater than 200 different chronic disorders that often lead to pulmonary fibrosis and the attendant morbidity and mortality. Distinguishing one ILD from another can be challenging even for experts given similar clinical manifestations. However, firm diagnosis is important for management, counseling, and surveillance. Computer-Aided Lung Informatics for Pathology Evaluation and Ratings (CALIPER, Mayo Clinic, Rochester, MN, USA), a machine learned image analysis tool for characterizing and quantifying diffused lung diseases on CT, has been shown to correlate with ILD mortality such as for idiopathic pulmonary fibrosis. The CALIPER assessment of ILD is not influenced by confounding conditions such as emphysema or pulmonary hypertension that may affect pulmonary function measurements. Moreover, CALIPER can provide more reproducible results with less inter- and intraobserver variability compared to the conventional subjective visual assessment of CT scans by radiologists. Herein, we aim to provide an overview of ILD and discuss CALIPER evaluation of ILD.
Application of lung ultrasound surface wave elastography for assessment of extravascular lung water in patients hospitalized with congestive heart failure
Authors: Wiley Brandon M. , Zhou Boran , Pandompatam Govind , Zhou Jinling , Olgun Kucuk Hilal , Zhang Xiaoming
Published: April 2019

Lung ultrasound (LUS) detects the presence of extravascular lung water (EVLW) through the visualization of B-Line artifacts. However, the qualitative nature of LUS limits its effectiveness in serial or longitudinal studies such as evaluating changes in EVLW at different time points in patients undergoing diuretic therapy for congestive heart failure. Lung ultrasound surface wave elastography (LUSWE) is a novel technique using a small handheld device that can measure superficial lung tissue elastic properties. We aimed to evaluate the use of LUSWE to measure quantitative changes in lung elasticity caused by acute changes in EVLW. We performed LUSWE on consecutive days in 14 patients hospitalized for acute congestive heart failure with evidence of pulmonary edema (clinical EVLW). From day#1 to day#2, the patients had an average diuresis of net negative 2.1 l associated with an average decrease in 13 B-Lines by lung ultrasound, signifying a reduction in EVLW. LUSWE analysis demonstrated a significant reduction (p < 0.05) in surface wave velocity in all interrogated intercostal spaces from day#1 to day#2. In summary, LUSWE performed at the bedside was able to demonstrate improvement in lung compliance (decreased elasticity) correlating with a reduction in EVLW in hospitalized patients being treated for congestive heart failure.
Reproducing tonguing strategies in single-reed woodwinds using an artificial blowing machine
Authors: Pàmies-Vilà Montserrat , Hofmann Alex , Chatziioannou Vasileios
Published: April 2019

Articulation on woodwind instruments is achieved inside the player’s mouth, where the tongue interacts with the vibrating reed, while the player adjusts the blowing pressure, the lip force, and the vocal tract configuration. The performed articulation technique defines the characteristics of the attack and release transients and thus the transitions between tones. In this study, an artificial blowing machine with a built-in tonguing system is used to analyze different tonguing strategies in single-reed woodwinds. The tonguing system is controlled via an electronically monitored shaker, offering the possibility to reproduce tongue articulation, while assuring repeatability. To reproduce different playing techniques, parameters obtained from measurements with players are used to set up the pressure in the artificial mouth and the behaviour of the tonguing system. During the experiment, the artificial-mouth pressure, the mouthpiece pressure, the reed displacement, and the shaker acceleration are recorded. The recorded signals are then compared to real-playing clarinet and saxophone measurements. Different trajectories for the artificial tongue are tested as well as different tongue-reed-contact durations. The artificial blowing and tonguing set-up, along with the images obtained with a high-speed camera, provide an in-depth understanding of the processes taking place inside the player's mouth.
Transients in wind instruments modeled with the Navier-Stokes equations
Authors: Giordano Nicholas
Published: April 2019

Transient components make an important contribution to the “color” of a musical tone. While such transients can be observed in experiments, realistic modeling can be very challenging. We describe a modeling study of initial transients in the tone produced by a recorder using Navier-Stokes-based simulations. We have studied how the harmonic content of a recorder tone during the attack portion of the tone depends on a variety of factors including the labium position, the presence of chamfers at the exit of the windway, and the initial dynamics of the blowing pressure. While our results are obtained for a realistic model of the recorder, they should also be applicable to similar instruments such as flue organ pipes. [Work supported by NSF Grant PHY1513273.]
Computational studies of flow in flue pipes
Authors: Thacker Jared W. , Giordano Nicholas
Published: April 2019

Direct numerical solutions of the Navier-Stokes (NS) equations have been used to study the air flow in a recorder. When the recorder is driven with a DC flow into the windway, we observe the familiar oscillating flow out of the window adjacent to the labium. The associated flow at the open end is also studied. For a pipe with a square cross-section, we find the flow at the open end to be small but nonzero, consistent with recent studies using speckle pattern interferometry by Coyle and Moore. In addition, we have analyzed the NS results for the air density so as to compare directly with the interferometry experiments. We also describe simulations for circular pipes. [Work supported by NSF Grant PHY1513273.]
The conflict of soundscape requirements with the introduction of alert signals
Authors: Fiebig André
Published: April 2019

Quiet road vehicles have to be equipped with acoustic alert signals for type approval to account for their potentially reduced audibility. According to the FMVSS No. 141, the alert sound has to be recognizable as a motor vehicle in operation that allows blind and other pedestrians to detect nearby electric vehicles or hybrid vehicles operating at lower speeds. Unfortunately, the detailed minimum sound requirements for type approval vary from regulation to regulation, for example, between FMVSS No. 141 and UNECE No. 138. The manufacturers can consider brand-related alert signal design within certain ranges but must adapt their alert sounds to the respective regulations, because an international harmonization of the signal requirements is missing. In this context, the impact on traffic noise in general and on soundscape in particular seems to be rarely systematically discussed. It is expected that some side issues will emerge with the systematic introduction of alert signals. Moreover, the effectiveness of the different regulations regarding the significant reduction of pedestrian collision risk was not systematically analyzed so far. This paper will discuss potential shortcomings of the introduction of alert signals regulated by law, and the implications on urban soundscapes will be outlined.
Isadore Rudnick's spectacular acoustics demonstrations
Authors: Keolian Robert M. , Baker Steven R. , Huffman Arthur
Published: April 2019

While soft-spoken in conversations and lectures, Isadore Rudnick could shout when teaching acoustics with demonstrations. At a special, auditorium stage, video-taped plenary session of the Fall 1980 meeting of the Acoustical Society of America, Izzy presented 90 min of spectacular acoustic demonstrations. The demonstrations ranged from simple ones common to acoustics classes to ones that filled the stage and involved elaborate equipment. This talk will be followed by a viewing of Izzy's plenary session video. It is hard to imagine that any acoustician would not find something of interest in, and indeed learn something from, this video. For those who wish to study Izzy's demonstrations further or present the material in a classroom, the video is available for ordering as advertised in the Journal of the Acoustical Society of America.
Signal detection theory and psychoacoustics
Authors: Conroy Christopher , Lentz Jennifer
Published: April 2019

This talk will trace the early history of signal detection theory (SDT) with a particular emphasis on its applications in psychoacoustics. SDT, as developed at the University of Michigan (U-M) in the mid-1950s, revolutionized psychophysics by introducing a core assumption: all sensory judgements are limited by “noise” of one sort or another and, as such, are reflective of underlying decision processes. To test and flesh-out this new theory, early empirical work in vision quickly turned to audition and a remarkably fruitful 12-year period followed, from roughly 1954 to 1966. This talk will focus on that 12-year period, bracketed, on the one end, by the establishment of an auditory research laboratory at U-M by Wilson P. “Spike” Tanner and, on the other, by the publication of Green and Swets’ (1966) seminal text. The principle documents and publications of that period—particularly those that appeared in this society’s Journal—will be reviewed, with a discussion of their intellectual and historical context. Emphasis will be given to the investigations of the Electronic Defense Group at U-M and those of other legendary psychoacousticians. In particular, the work of Tanner, the key instigator in the transition from “statistical decision theory” to SDT in psychoacoustics, will be discussed.
Extending signal detection theory approaches up the central pathway: Auditory midbrain models
Authors: Carney Laurel H. , Furst Miriam
Published: April 2019

The application of signal detection theory (SDT) to peripheral encoding of stimulus parameters provided a quantitative basis for understanding auditory-nerve (AN) responses. Siebert’s development of this strategy, based on relatively simple analytical models, laid the groundwork for Heinz’s extension that took advantage of computational AN models. These studies applied the Cramer-Rao lower bound (CRLB) to estimate just-noticeable differences of stimulus parameters, assuming that underlying neural responses could be described as non-homogenous Poisson processes (NHHP) and that the brain acts as an optimal processor. Krips and Furst carried this approach into the central nervous system, first showing that coincidence-detector neurons that receive excitatory and/or inhibitory NHHP inputs produce outputs that are also NHHP. These models were tested using the CRLB for sensitivity to interaural differences in time and level. Here, we carry the approach a step further along the auditory pathway to the auditory midbrain. Model neurons that combine excitatory-excitatory and etxcitatory-inhibitory mechanisms explain rate tuning for the amplitude-modulation frequency, a key response property of inferior colliculus (IC) neurons. These models also exhibit direction selectivity for fast frequency sweeps observed in IC responses to Schroeder-phase harmonic complexes. These models facilitate SDT predictions of psychophysical tasks involving amplitude and frequency fluctuations.
The invasion of psychoacoustics by inferential statistics
Authors: Yost William , Pastore M. Torben
Published: April 2019

The basic results that form the psychoacoustic foundation of our current knowledge of auditory perception, collected over nearly 50 years, were generated without any use of null-hypothesis significance testing (inferential statistics). The common use of inferential statistics in psychoacoustic articles published in JASA did not occur until the 1980s. Yet, today it is almost impossible to publish a psychoacoustic article in JASA, or anywhere else, without using inferential statistics. In addition, recent controversies concerning replication in the social and behavioral sciences are beginning to encroach on the field of psychoacoustics. In this presentation, a case will be made that several elements of the experimental design inherent to many, if not most, psychoacoustic experiments often make the use of inferential statistics unnecessary. These aspects (many derived from the framework of the Theory of Signal Detection) include careful experimental control of stimuli and response acquisition, ratio-scale measurements, experienced subjects, large number of trials per subject, within-subject (repeated measures) experimental design, and strong theoretical context (e.g., an ideal observer). Some scenarios of experimental design and data presentation will be considered, suggesting that inferential statistical analysis might not be needed in some psychoacoustic research. [Work supported by NIDCD and Facebook Reality Labs.]
Listener sensitivity to structured phonetic variation
Authors: Theodore Rachel M.
Published: April 2019

Memory for spoken language is not a veridical representation of experience. Instead, memory reflects integration across our interlocutors’ messages, resulting in robust memory for meaning with relatively poor memory for the specific form of the message. This is striking considering that in the process of mapping from speech to meaning, listeners show exquisite sensitivity to the acoustic-phonetic structure of speech. In this talk, I will review selected findings from work in our laboratory that examines listeners' ability to dynamically adapt to structured phonetic variation, focusing on variation associated with talkers' idiolects. These studies examine mechanisms that allow listeners to exploit structured variation for speech perception, voice recognition, and memory of spoken language. Collectively, the results (1) identify principles that govern how listeners modify the mapping to speech sounds to reflect cumulative experience with talkers’ phonetic input, (2) show that sensitivity to structured phonetic input facilitates identification of a talker’s voice in addition to the linguistic message, and (3) demonstrate that talker identity provides a critical structure for the integration of spoken language in memory. These findings help explicate a theoretical framework that accounts for tension in a linguistic architecture that uses both abstract and instance-specific representational knowledge to guide spoken language processing.
Long-range detection of a spherical target located near the gas-saturated bottom
Authors: Grigorieva Natalie S.
Published: April 2019

The study is devoted to modeling of the backscattering from a spherical target located near the gas-saturated bottom. Two cases are compared: when the sound speed in sediment is larger and smaller than the sound speed in water (rigid and soft bottom). The bottom is assumed to be a homogeneous attenuating fluid half-space. The transmitter/receiver is located in a homogeneous water half-space. Modeling is performed in the frequency band of 70–90 kHz for distances between the target and transmitter/receiver from 500 m up to 1 km. The spherical scatterer of a radius a is assumed to be acoustically rigid; 0.3 < a < 0.5 m. For calculating the echo signal in the frequency domain, we have followed the Hackman and Sammelmann's general approach. The arising scattering coefficients of the sphere were evaluated with the use of the steepest descent method. The use of the obtained asymptotic formulas for the scattering coefficients allowed to decrease essentially a number of summands in the formula for the form function of the backscattered acoustic field. [Work supported by Russian Ministry of Educ. and Sci. under Grant 02.G25.31.0149.]
The research of passive detection parameter measurement based on vector sensor
Authors: Hui Juan , Bu Xianzhong , Zhao Anbang , Wang Dayu , Li Jin
Published: April 2019

As one of the indispensable technologies for underwater target detecting, underwater acoustic passive detection technology has always been a hot spot in marine system research. A vector sensor can detect underwater targets by combination with the pressure and vibration velocity information; vector sensor array can obtain higher gain than pressure array with the same number hydrophones. Vector sensor can reduce the length of the underwater sensor array and can detect underwater targets in the case of low signal to noise ratio. This is the goal that many researchers strive to solve for many years; therefore, vector sensor passive detection technology has far-reaching scientific research value. Through the verification of the simulation experiment, the azimuth estimation technique and the adaptive frequency estimation technique are feasible. By estimating the azimuth sequence and frequency sequence of the target radiation signal, the relevant information of the target can be obtained, so it is of great significance in the research of underwater acoustic detection technology.
Computational methods for describing acoustic propagation in forests
Authors: Swearingen Michelle E.
Published: April 2019

Acoustic propagation through stands of trees, both large and small, can be markedly different from propagation through an open environment. Ground properties, meteorology, and significant scattering effects all play a role. An understanding of these effects, and computational methods used to describe them, can be utilized in applications ranging from noise mitigation to wildlife communication. This tutorial explores the myriad of computational methods that have been developed to describe acoustic propagation in forested environments. Beginning with the early simple empirical models describing attenuation, the presentation then narrows the field of view to contributions of individual components within a forest. Models for describing scattering by trunks and foliage, both individually and as ensembles, are presented. Next, the integration of these individual components into the fully coupled system that includes ground properties and meteorology, within computational methods such as the parabolic equation (PE) and finite-difference, time-domain (FDTD) methods are shown. Finally, examples are presented showing how computational methods for forest acoustics can be used for evaluating noise mitigation strategies and wildlife studies.
West Hollywood Library—More than just another pretty space
Authors: Hoover K. Anthony
Published: April 2019

The West Hollywood Library is a 35 000 sqft branch of the County of Los Angeles Library, with construction funded by the City and operated by the County. It serves as a cultural and artistic community center, and includes a children’s library, teen center, career development center, special collections, café, bookstore, two parking garages, community meeting room, and multipurpose public meeting room (for council and commission meetings, performances, and other uses). An ornamental wood ceiling, the wood stage in the multipurpose meeting room, the children’s reading room, and the overall aesthetic presented interesting challenges for acoustics. Visual aesthetic and acoustic performance aspects will be discussed, along with references to various other library projects.
Acoustic design of today's library
Authors: Swallow John C. , Wesolowsky Michael J.
Published: April 2019

Modern libraries are very different from past libraries, offering multiple services and having wildly different acoustic requirements. Reviewed are new uses and functional requirements: more than just a traditional information resource, the library features information sharing, collaboration, dissemination and production as a media centre. A brief history of library design is provided. Over decades, library design philosophy has evolved which has provided its own challenges. Modern building design presents more challenges; adding in the new users and uses—which even vary by age group, the acoustic designer now faces enormous challenges. Acoustic design measures are reviewed and found wanting: new measures are needed. Case studies show the variety of uses, novel design solutions and highlight how a detailed knowledge of actual users and uses is required to allow all the functions to more-or-less comfortably co-exist.
Graduate programs at the University of Maryland
Authors: Hoover Eric C. , Anderson Samira B. , Goupell Matthew , Gordon-Salant Sandra
Published: April 2019

The University of Maryland has many opportunities for graduate studies in topics in acoustics, including hearing, speech and language sciences, neuroscience, physiology, bioacoustics, linguistics, and acoustical and communications engineering. Graduate training at the University of Maryland is characterized by an emphasis on multidisciplinary, collaborative research designed to enable students to develop a breadth of knowledge in addition to their focused research program. There are numerous interdisciplinary initiatives that address problems of great importance to science and society. In addition to the interdisciplinary research training on campus, students also train and collaborate with world-class researchers from nearby institutions including National Institutes of Health, Walter Reed National Military Medical Center, the University of Maryland Medical Center, and many other outstanding institutions in the area. Individuals interested in graduate training at the University of Maryland should contact faculty in their field of interest to learn more about the many opportunities available.
Graduate research opportunities in acoustics at the University of Michigan, Ann Arbor
Authors: Flynn Tyler J. , Dowling David R.
Published: April 2019

The University of Michigan (UM) is host to a wide array of acoustics research which encompasses many of the Technical Committees of the ASA. Within the Department of Mechanical Engineering alone, work is being done to develop better remote sensing techniques for underwater environments, to better understand the mechanics of the human cochlea, and to build metamaterials allowing for new and exotic acoustic behaviors. Within the UM Medical School, faculty and graduate students are constantly advancing techniques for diagnostic and therapeutic ultrasound procedures. In the Department of Naval Architecture and Marine Engineering, computational and experimental tools are being developed to enable better ship design. In Electrical Engineering, advances in MEMS fabrication yield even smaller and more efficient transducers for smarter devices. And researchers in the Linguistics Department are using the fundamental acoustic processes of speech to learn how humans effectively communicate. And while these are only a sample of the projects taking place at Michigan, new opportunities for acoustics research and collaboration open up each semester. Combined with a rich course catalogue, first-rate facilities, and great prospects for publication, these opportunities prepare UM graduate students for careers in industry and academia alike. Go Blue!
Graduate studies in acoustics at the University of New Hampshire
Authors: Howard Daniel R. , Lyons Anthony P. , Miksis-Olds Jennifer L. , Weber Thomas C.
Published: April 2019

The University of New Hampshire (UNH) offers several opportunities for graduate students interested in studying acoustics and its application. Faculty mentors who are expert in acoustic methods and technologies reside in a range of programs and departments that are largely focused on the use of acoustics in the marine environment, including biological science, earth science, mechanical engineering, natural resources and earth systems, ocean engineering, and oceanography. UNH faculty mentors who specialize in acoustics are active in the Animal Bioacoustics, Acoustical Oceanography, and Underwater Acoustics technical committees. Recent studies by faculty and students focusing on fundamental acoustic problems, such as those that would cause a graduate student to be a regular attendee of meetings of the Acoustical Society of America, have come largely from mechanical engineering, ocean engineering, biological sciences, and the newly formed School of Marine Sciences and Ocean Engineering. Graduate students in these programs of study have the opportunity for formal classroom training in the fundamentals of acoustics, vibrations, and advanced topics in acoustics as they pursue their graduate training.
A master’s degree in acoustics through distance education from Penn State
Authors: Russell Daniel A. , Sparrow Victor
Published: April 2019

The Graduate Program in Acoustics at Penn State provides online access to graduate level courses leading to the M.Eng. degree in Acoustics. Lectures are broadcast live via Adobe Connect to students scattered around the world, while archived recordings allow working students to access lectures at their convenience. Students earn the M.Eng. in Acoustics degree by completing 30 credits of coursework (six required courses and four electives) and writing a capstone paper. Since 1987, more than 150 distance education students have completed the M.Eng. in Acoustics degree. Many other students take individual courses as non-degree students. Courses offered online include: elements of acoustics and vibration, elements of waves in fluids, electroacoustic transducers, signal processing, acoustics in fluid media, sound and structure interaction, digital signal processing, aerodynamic noise, acoustic measurements and data analysis, ocean acoustics, architectural acoustics, noise control engineering, nonlinear acoustics, outdoor sound propagation, computational acoustics, biomedical ultrasound, flow induced noise, spatial sound and 3D audio, acoustics of musical instruments. This poster describes the distance education experience leading to the M.Eng. degree in Acoustics from Penn State and showcases student demographics, capstone paper topics, enrollment statistics and trends, and the success of our graduates.
Opportunities for graduate studies in physical, engineering, and underwater acoustics at the Naval Postgraduate School
Authors: Godin Oleg A. , Smith Kevin B. , Pickens Anne T.
Published: April 2019

The Departments of Physics and of Electrical and Computer Engineering at the Naval Postgraduate School offer programs of graduate studies in acoustics leading to MS degrees in physics, applied physics, and engineering acoustics and PhD degrees in engineering acoustics and applied physics. The program is interdisciplinary, with courses and laboratory work drawn principally from the fields of physics and electrical engineering. Subjects covered include waves and oscillations; fundamentals of physical and structural acoustics; the generation, propagation and reception of sound in the ocean; civilian and military applications of sonar systems; and acoustic signal processing. Topics of recent theses and dissertations include development and field testing of novel sensors for atmospheric and ocean acoustics, modeling and measurements of ambient noise and sound propagation in the ocean, sound scattering in underwater waveguides, acoustic vector sensors and vector field properties, acoustic communications, geo-acoustic inversion, acoustic remote sensing of the ocean, and acoustics of autonomous underwater and aerial vehicles.
Non-destructive correlation of Nigerian drum beat-pattern and pitch to detect a ripen watermelon
Authors: Onwubiko Stephen G. , Neilsen Tracianne B.
Published: April 2019

In the application of musical acoustics and speech sound, almost any type of Nigerian drum is used for communication. The agreeable successions of tones unlimited to interesting beat-patterns, pitch and rhythms uses shifted accents, non-accented rhythms, syncopations etc. On the daily basis of a watermelon harvesting and trade point, musical acoustics and speech sounds are applied passively in detecting and determining a ripen watermelon; the application of the Nigerian drum beat-pattern, pitch and intonation is an efficient procedure for ripeness detection of watermelon. Depending on how the pitches are lowered or accented, the melon ripeness is detected. The pitch-pattern analysis can be used to measure, determine and correlate the internal ripeness and quality of watermelon with pitch from a Nigerian drum. This method allows identification at a 60.0 % level of efficiency. Hence, the proposed method can reliably detect watermelon ripeness.
Developments in resonant, low frequency sound absorbing devices: trials, errors and successes
Authors: Madison Jeffrey
Published: April 2019

Nowhere is it more prevalent in the acoustical treatment world where the predicted can deviate from the actual outcome than in resonant, low frequency sound absorber design and construction. Any worthwhile resonant sound absorber (RSA) is a system, multiple parts working together toward a common design goal. RSAs can be designed via mathematical prediction, Helmholtz much more accurately than membrane configurations. Regardless of the predictions, when the time comes to construct RSAs, each and every component that goes into and that must work with the other components in the system, whether in a factory setting or in field construction, will have a significant influence on the actual outcome. Prediction techniques swiftly identify resonant frequencies, for example, however can miss widely on bandwidth and efficiency due to variables introduced during construction. It is therefore important to use experimentation and measurement techniques to understand actual outcome possibilities. One example of this is utilizing a large format impedance tube that measures designs effectively down to 20 Hz. Examples of RSAs along with their development and testing will be presented.
Displacement of the stapes differs across species—Implications for studies of auditory function
Authors: Peacock John , Alhussaini Mohamed , Greene Nate , Tollin Daniel J.
Published: April 2019

Sound is transferred to the cochlea via the middle ear. The anatomy and physiology of the middle ear varies significantly across species, and these differences impact both the stimulation provided to the inner ear, and the suitability of different animal models for use in various types of research. Studies of auditory trauma from blast, for example, require generation of intracochlear pressures with sufficiently high intensities to cause damage. In some species, e.g., mice and rats, it may not be possible to generate sufficiently high pressures through air conducted sound alone, whereas in humans sufficiently high pressures can readily be generated through air conduction. We hypothesize that this is due to limits on the displacement of the stapes by the stapedial annular ligament, which thereby constrains the energy transferred to the cochlea through the middle ear. To test this hypothesis, we made measurements of the motion of the middle ear bones in response to tones of varying intensities and frequencies in several different species commonly used in laboratory research. Our results reveal peak stapes displacements from ~150 um in humans to 10-20 um in mice and rats. We will discuss the implications of these findings for basic studies of auditory function.
Detection and intensity discrimination of a sinusoid with and without masker uncertainty
Authors: Conroy Christopher , Mason Christine , Kidd Gerald
Published: April 2019

The effect of stimulus-based uncertainty on the shape of the masking function at circa-threshold pedestal levels was investigated. Of particular interest was how uncertainty regarding properties of the masker affects the magnitude of “negative masking” [Raab et al., J. Acoust. Soc. Am. 35, 1053 (1963)] that is obtained under different stimulus configurations. Intensity discrimination thresholds for gated, 100-ms, 1000-Hz sinusoids were measured at three pedestal levels: -9, 0, and 9 dB re: absolute threshold. A two-interval, two-alternative forced-choice procedure was used. Under the reference condition, thresholds were measured in quiet. In comparison conditions, thresholds were measured in the presence of one of two masker types: (1) a notched-noise masker or (2) a random-frequency, multicomponent masker. In the multicomponent masker condition, uncertainty was imposed by roving the frequency components that comprised the masker from interval-to-interval over a block of trials. The data under each condition were fit with psychometric functions and slope estimates were obtained. Results are discussed with respect to the factors that govern, and possible mechanisms underlying, negative masking. Specifically, two possible explanations for the “dip” in the masking function are examined: nonlinear transduction [Hanna et al., J. Acoust. Soc. Am. 80, 1335 (1986)] and observer uncertainty.