bluuebunny/crossref_metadata_2025 huggingface dataset:
Transmission loss measurements using a scanned array nearfield acoustical holography technique in an anechoic/reverberation facility. Part I. Measurement methodology.
Authors: Kremer Alex J. , Sklanka Bernard J.
Published: July 2011

Transmission loss is an important metric when used to assist in the selection of materials for noise control and design. In order to assess and improve the performance of transmission loss measurements, two different techniques were compared: traditional microphone and/or matched pair microphone intensity anechoic chamber chamber-side techniques, and nearfield acoustical holography (NAH) techniques. Intensity and sound power measurements using traditional methods were made on a test panel installed in an anechoic-reverb facility transmission loss window, then repeated using a conformal nearfield microphone array and nearfield acoustical holography processing techniques. In order to process the data with the relative phase between microphones preserved, a set of stationary reference signals was used. A number of spectral preprocessing techniques and reference combinations are presented. The nearfield acoustical holography processing methodology is also presented with an emphasis on data quality and error reduction.
Near-field measurement of the scattering characteristics of an object based on Doppler signal filtering.
Authors: Salin Boris M. , Salin Mikhail B.
Published: July 2011

The scattering characteristics of an object can be measured by insonification with tonal signals and reception by a linear array located in the near field of the object. This paper discusses possible signal processing algorithms designed to measure the angular dependence of the target strength of the scatterer. The measurement is based on (1) moving the object parallel to the array, (2) obtaining 2-D Fourier transform of the received signal in time and space coordinates, (3) the use of a Doppler frequency filter, and (4) selecting the maximum values (as a function of time) of the power spectral density along the trajectory of the moving object in coordinates of frequency and angle. This method gives greater signal to noise ratio than traditional stationary (object not moving) measurement schemes. The possibility of these measurements is estimated using experimental data on the angular and frequency characteristics of reverberation caused by the tonal source. The minimum values of target strength that can be measured in an area with low sea state (i.e., quiet conditions) are determined. [B.M.S. and M.B.S. gratefully acknowledge the generous support of the U.S. Office of Naval Research, ONRG.]
Optimized design and analysis of sparse-sampling functional magnetic resonance imaging experiments of speech and hearing.
Authors: Perrachione Tyler K. , Gabrieli John D. E. , Ghosh Satrajit S.
Published: July 2011

Functional magnetic resonance imaging (fMRI) offers an unparalleled opportunity to investigate the brain bases of speech and hearing. However, the high-amplitude (>90 dB) acoustic noise that occurs during MR image acquisition presents a serious obstacle to research on speech perception and production. “Sparse sampling” is an alternate acquisition strategy that mitigates the interference of this acoustic noise by inserting a delay between subsequent image acquisitions, allowing auditory stimulus presentation or speech production during this silent period. Although this technique is routinely employed in auditory fMRI, there has been no empirical attempt to optimize the design of sparse sampling paradigms to maximize detection of whole-brain blood-oxygen level dependent (BOLD) signal. Moreover, the discontinuous nature of the sparse-sampling timeseries has led to the use of analysis models that fail to account for dynamic properties of the hemodynamic response: thus seriously underestimating BOLD signal and limiting the types of cognitive brain activity, sparse sampling is able to detect. We present computational modeling and human neuroimaging experiments that explore the parameter space of sparse sampling experiment design and analysis—including delay duration, stimulation frequency, and hemodynamic response convolution—and offer significantly enhanced detection of brain activity during speech perception tasks versus conventional methods.
Estimation of the empirical Green's function from ambient noise in the ocean.
Authors: Menon Ravi , Gerstoft Peter , Hodgkiss William
Published: July 2011

The empirical Green’s function obtained from cross-correlations of ambient noise has several applications such as passive imaging, acoustic monitoring, remote sensing, etc. In general, long periods of averaging are necessary to obtain stable estimates. Short time averages suffer from directional biases due to the changing noise field and the dominating effect of loud sources such as ships, in addition to having a low signal to noise ratio. In this paper we analyze the eigenvalues and eigenvectors of the cross-spectral density matrix from short time estimates. Recent results in statistical theory are used to separate the random noise component from meaningful information. By retaining only those eigenvalues and eigenvectors that contribute toward the buildup of Green’s function, we can reduce the time required to obtain a stable estimate and achieve higher signal to noise ratios. Results are presented from the SW06 data.
Operational wind farm noise and shipping noise compared with estimated zones of audibility for four species of fish.
Authors: Andersson Mathias H. , Sigray Peter , Persson Leif K.G.
Published: July 2011

A comparison between different underwater sound sources such as ships and operational wind farms are not straightforward to perform due to their qualitative difference in signal properties. However, in order to study possible effects of noise on fish, this comparison has to be made, and possible cumulative effects investigated. This study shows that a wind farm located in a shallow area in the Baltic Sea will add significant noise levels to the region even though intense shipping activities occur. This is due to the fact that the wind farm produces a strong tonal component at 127 Hz, a frequency otherwise relatively unaffected by shipping noise. The results were obtained by developing a numerical acoustic model of the wind farm taking account of their integrated effect. The model was evaluated against measurements performed at several distances from the wind farm during various weather conditions. Additionally, zones of audibility for cod, herring, salmon, and European eel were estimated.
Noise measurements of a prototype tidal energy turbine.
Authors: Deveau David M. , Stein Peter J. , Rotker Nicholas A. , Scribner Herbert C. , Edson Patrick
Published: July 2011

Characterizing the acoustic footprint of power-generating tidal turbines is necessary to assess possible effects of the radiated noise on local marine life. However, as is the case for a wide-range of offshore installations, cohesive and accurate measurement of both the radiated noise of the turbine and the ambient noise conditions is a difficult task. In this case, the usual difficulties with propagation and contaminating noise sources are exacerbated by flow induced noise in the measurement system. Here we present results from noise measurements made of the Ocean Renewable Power Company prototype TidGenTM power generation turbine unit deployed in Cobscook Bay near Lubec and Eastport, Maine. These measurements were made using a drifting measurement system in currents upwards of 6 kn.
A theoretical framework for quantitatively characterizing sound field diffusion and sound energy decay curves based on the scattering coefficients and absorption coefficients of walls.
Authors: Hanyu Toshiki
Published: July 2011

A theoretical framework for characterizing sound field diffusion based on the scattering coefficients and absorption coefficients of walls was developed. The concepts of the equivalent scattering area, equivalent scatter reflection area, average scattering coefficient, and average scatter reflection coefficient are introduced in order to express each room’s capability of scattering. Using these concepts and the mean free path, the scatter-to-absorption ratio, mean scatter time, and the diffusion time are defined in order to evaluate the degree of diffusion of a space. Furthermore a theoretical model for characterizing sound energy decay curves in a non-diffused sound field based on the above mentioned concepts was also developed. First a reverberation model for a room which consists of perfect specular reflective walls was examined. Second the scattering coefficient was introduced to the above reverberation model in order to consider the effects of the sound scattering from the walls on the energy decay curves. Using this theoretical model, a non-linear energy decay curve in a non-diffused sound field, such as a room which has uneven absorption, can be calculated considering the effect of the walls’ scattering. The results of computer simulations supported the theoretical framework that the ideas presented here are basically valid.
Relationships between diffusion and scattering.
Authors: Rife Brian , D’Antonio Peter
Published: July 2011

ISO 17497-1 and ISO 17497-2 describe two approaches to measure and characterize scattering and diffusion, respectively, from surfaces. This paper will present experimental results on several samples illustrating both coefficients and a comparison between results obtained from each standard. Scattering coefficients determined from ISO 17497-1 and those obtained from the polar responses of ISO 17497-2, using correlation between reflector and scatterer, as well as the ratio of specular energy to total energy, will be presented. A discussion of the significance of ISO 17497-1 for 1D extruded shapes and samples containing absorption will also be given. Lastly, a theoretical proposal to relate the diffusion and scattering coefficients will be presented, in which a bound on the diffusion coefficient for a given scattering coefficient is derived.
Sound strength parameter G in concert hall design.
Authors: Beranek Leo
Published: July 2011

The parameter “Strength of Sound G” is closely related to loudness. Its magnitude is dependent, inversely, on the total sound absorption in a room. By comparison, the reverberation time (RT) is both inversely related to the total sound absorption in a hall and directly related to its cubic volume. Hence, G and RT in combination are vital in planning the acoustics of a concert hall. A newly proposed “bass index” is directly related to the loudness of the bass sound and equals the value of G at 125 Hz minus its value at mid-frequencies. Listener envelopment (LEV) is shown for most halls to be directly related to the mid-frequency value of G. The broadening of sound, i.e., apparent source width (ASW), is given by effective spatial impression (ESI) which is determined from the combined effect of early lateral reflections and strength G. The importance of considering G when planning the acoustics of concert halls is emphasized.
Vocalization source levels of adult male northern elephant seals (Mirounga angustirostris).
Authors: Southall Brandon L. , Insley Stephen , Holt Marla , Reichmuth Colleen
Published: July 2011

Aerial vocalization source levels were obtained for adult male northern elephant seals from 1999–2010. Vocalizations from known individuals (marked within years) were selected from three breeding seasons (1999–2000, 2004–2005, and 2009–2010) evenly spaced during this interval so that it is unlikely animals were resampled across seasons. Sound pressure levels of calls were measured on-axis (0-deg orientation) at 1-m range using Brel and KJær 2203 and 2250 precision sound level meters. Calls almost always occurred in series, as previously described; the maximum received level for any pulse in each series is used as the source level. Source levels are reported for individuals with at least four complete bouts. All sex/age classes were measured; the adult male data will be discussed and compared with other mammals in terms of rms levels (two temporal weighting functions) and peak sound pressure levels. Results indicate that calls almost always exceed 100 dB rms (re: 20 μPa) with peak levels regularly exceeding 120 dB. These loud sounds might suggest long-range communication, but considering hearing data Ron Schusterman and Dave Kastak first collected on this species and environmental noise levels in their rookeries, intense signals are likely required even for the small ranges over which they apparently function. [Funding provided by ONR.]
Source characteristics of the underwater knocking displays of a male Pacific walrus (Odobenus rosmarus divergens).
Authors: Hughes William R. , Reichmuth Colleen , Mulsow Jason L. , Næsbye Larsen Ole
Published: July 2011

Walruses breed in winter at high latitudes in conditions that make close-range observations difficult. Males are known to produce complex underwater songs that can extend over multiple days and propagate over several kilometers. These acoustic displays are comprised of highly rhythmic sharp “knocks” punctuated by occasional metallic “bells.” The source characteristics of the knocking sounds that were regularly emitted by a male walrus raised in captivity were examined. Knocks were produced as single 20 ms pulses, or as doublets and triplets, and were typically repeated at rates of 0.8/s to 1.2/s. These were loud sounds with greater bandwidth than previously reported: mean source levels were 186 dB pk-pk re 1 μPa at 1 m (range 161–196) with maximum frequency >24 kHz. Production of each knock was associated with visible impulsive movement of the forehead. During rut, this walrus had difficulty inhibiting sound production and would often continue to emit knocks in air during haul-out and even while eating, suggesting an endogenous component to this behavior. A strong correlation between his seasonal testosterone levels and the persistence of knocking displays was confirmed. Captive research provides unique access to acoustic and reproductive behavior that is presently impossible to study in wild walruses.
Waveguide invariant analysis for modeling time-frequency striations in a range-dependent environment.
Authors: Sell Alexander W. , Culver R. Lee
Published: July 2011

The waveguide invariant is a useful parameter for understanding the behavior of interference patterns that arise from broadband acoustic sources in shallow water waveguides. These interference patterns often appear in time-frequency plots in the form of striations, whose properties are directly related to the environmental parameters that characterize the waveguide. These parameters include, but are not limited to, the sound speed profile, bathymetry, sediment properties, and source depth. Prior formulations of the waveguide invariant are not fully range- and depth-dependent and thus perform well only in selected environments. This talk will discuss the use of a novel range-dependent waveguide invariant distribution to describe striations seen in acoustic data taken during a 2007 experiment that occurred along the continental shelf of southeast Florida. The performance of this approach and its applicability to range and depth localization will be discussed. [Work supported by ONR Undersea Signal Processing.]
Acoustic modeling of the southeast Florida continental shelf and slope in three dimensions.
Authors: Ballard Megan S. , Knobles David P.
Published: July 2011

This work is concerned with modeling the multipath arrivals observed during the CALOPS experiment which occurred off the southeastern coast of Florida in 2007 [K. D. Heaney and J. J. Murray, J. Acoust. Soc. Am. 125, 1394–1402 (2009)]. The received signals were measured on a horizontal line array and a direct and a refracted path were identified from their arrival angles. The received levels of these signals differed significantly in amplitude owing to the different sediments encountered along each of the respective propagation paths. Using previous results from geological surveys as well as from smaller, localized acoustic experiments, a 3-D model of the seabed over a 70 × 40 km2 area of the continental shelf and slope was constructed. The seabed parameters (sound speed, density, attenuation, and seafloor roughness) were then used as inputs to a 3-D propagation code to model the observed data. [Work supported by ONR.]
An acoustic tomography scheme with a bottom mounted horizontal line array.
Authors: Li Zhenglin , He Li , Li Fenghua , Zhang Renhe , Badiey Mobson
Published: July 2011

The sound speed profile plays an important role in shallow water sound propagation. And much attention has been paid on how to obtain it. Concurrences with in-site measurements, many inversion methods have been put forward to estimate sound speed profile from acoustic signals received by a vertical line array. The feasibility and robustness of an acoustic tomography scheme with matched field processing are studied. The acoustic signals from a horizontal line array in South China Sea are analyzed to invert sound speed profiles, in which the sound speed profile is described by the empirical orthogonal functions to reduce the unknown parameters. Parallel genetic algorithm is adopted as the optimization algorithm to increase the inversion speed. The results show that the inverted sound speed profiles are in good agreement with in-site measurements. Moreover, the a posteriori probability analysis is used to verify the validity of the inverted results. [Work supported by the National Natural Science Foundation of China under Grant No. 10974218 and the Knowledge Innovation Program of the Chinese Academy of Sciences, Grant No. KZCX1-YW-12-2.]
Integration of ocean and acoustic field modeling in partially specified environments.
Authors: Finette Steven , Gerdes Frank , Evans Thomas , Shen Colin
Published: July 2011

The problem of accurately predicting the characteristics of acoustic fields propagating within an ocean environment depends on the amount of information available concerning that environment, an issue that has received considerable attention in recent years. From a modeling perspective, a major goal of this research effort is to achieve robust quantitative estimates of acoustic field uncertainty associated with incomplete knowledge of environmental parameters and fields, so that decisions or actions conditioned on the results of numerical simulation accurately reflect the current state of information. Exact knowledge of these quantities is not available and one can represent such an incomplete state of knowledge (uncertainty) by probability distributions on environmental parameters and fields. We consider a polynomial chaos framework for modeling both environmental and acoustic field uncertainty in an integrated framework. An example is presented of submesoscale space-time evolution of the sound speed field under uncertain initial conditions associated with tidal forcing and temperature in a canonical shelf-break environment, with corresponding estimates of acoustic field intensity caused by this uncertain ocean environment. Alternatives to probability-based modeling of uncertainty are briefly addressed. [Work supported by the Office of Naval Research.]
Subharmonic response from ultrasound contrast microbubbles for noninvasive blood pressure estimation.
Authors: Katiyar Amit , Sarkar Kausik , Forsberg Flemming
Published: July 2011

Estimation of local organ-level blood pressure can help in diagnosing and monitoring heart and vascular diseases. Subharmonic signals from ultrasound contrast microbubbles have been proposed as a noninvasive alternative to the current practice of using a manometer-tipped catheter. Approximately 10 dB linear decrease in subharmonic component with 25 kPa pressure increase (typical blood pressure variation) has been reported for several contrast microbubbles. A theoretical investigation of the underlying phenomenon will be reported here. First the well-established model of a free microbubble is studied to show that reduction in subharmonic with ambient pressure increase occurs only below a certain excitation frequency. Above another critical frequency, subharmonic signal increases with ambient pressure. In between the variation is nonmonotonic. Furthermore, where it decreases with ambient pressure, the relationship is linear only above a certain excitation pressure. The behavior is explained by analyzing the dependence of resonance frequency of a bubble on the ambient pressure. The dependence of the critical frequencies on bubble radius and possibly bubble size distribution will be discussed. Behaviors for several models for encapsulated contrast microbubbles will also be reported. [Work Supported by the NSF and the NIH.]
Soil plate oscillator: Modeling nonlinear mesoscopic elastic behavior and hysteresis in acoustic landmine detection.
Authors: Duong Dang V. , Korman Murray S.
Published: July 2011

An experimental apparatus, designed to study flexural vibrations of a soil loaded plate, consists of a thin circular elastic plate clamped at the boundary between thick round flanges. The soil column is supported by the plate and upper cylindrical wall. A small magnet attached to the center of the plate is driven by a rigid ac coil (located coaxially below the plate) to complete the electrodynamic soil plate oscillator (SPO) design. Measurements of the electrical motional impedance Zmot of the SPO versus frequency are made using the complex output to input response of a Wheatstone bridge that has an identical coil element in one of its legs. The mechanical impedance Zmech (force/particle velocity, at the plate’s center) is inversely proportional to Zmot. Experiments, with and without mass loading at the plate’s center, verify Snowden’s theory for a clamped plate [J. Acoust. Soc. Am. (1971)] and help establish mechanical parameters. Resonant oscillations (for various point mass loadings) provided effective mass, spring, damping and coupling constant parameters of the system. “Tuning curve” behaviors of real {Zmot} and imaginary {Zmot} at successive vibration amplitudes (for various soil column heights) are used to develop a general mesoscopic nonlinear elastic model for granular media.
Monaural source separation in underground spaces via non-negative and complex matrix factorization.
Authors: King Brian J. , Atlas Les E.
Published: July 2011

Automated separation of multiple independent acoustic sources collected on a single monaural sound channel is an active research area and can aid in many applications, including practical automatic speech recognition, speaker identification, and keyword identification in multitalker, noisy, and/or reverberberant multisource environments. Some of the latest and most promising methods of single-channel source separation are non-negative and the even more recent complex matrix factorization, which decompose a signal into a sparse linear combination of source-specific building blocks, commonly referred to as bases. Once the bases and accompanying weights are calculated, separating a source from the mixture is achieved by multiplying and summing together its corresponding bases and weights. While experiments exhibit significant separation, the majority of this work has been done on studio-recorded audio and consequently little done in more realistic acoustic environments. Some of the most important environments are underground spaces, which are usually heavily damped, highly reverberant, and noisy. In this work, we will develop and compare matrix factorization single-channel source separation algorithms in reverberant conditions which simulate acoustic transmission through tunnels and other underground environments. We will conclude by demonstrating the most promising methods and discussing their current limitations. [This research was supported by AFOSR Grant No. FA9550061019.]
Tips and tools for talking to the press.
Authors: Bardi Jason S
Published: July 2011

Your latest paper is about to be published in a major journal, your press officer has issued a news release to the media, the phone is starting to ring off the hook, and your inbox is filling up with emails ending with domain names such as bbc.co.uk and discovermagazine.com. Now what? How can you get the most for yourself and your field out of this latest 15 min of fame? Join Jason Bardi, veteran press officer at the American Institute of Physics, set for a discussion of what journalists expect and hope to get from an interview. Hear about your rights and responsibilities as a source. Learn how to make the most of your time with the press, including best practices for handling media inquiries and helpful hints for describing your work.
Talking to the media: Lessons in crossing the great divide.
Authors: Kuhl Patricia K.
Published: July 2011

Most scientists consider talking to the media akin to crossing a minefield with no protection. You not only have to worry about potentially making a fool of yourself or failing to describe your work in language a lay audience can digest. You also have to worry about properly highlighting the role played by your institution, your home department, your funding agency, your donors, your co-authors, and your colleagues, who (no matter what you say), will believe you focused unduly on your own work to the exclusion of theirs. The press will not allow you to review the to-be-published story so you will not be able (even with exquisite attention to detail) solve the issues raised above. What’s a scientist to do? For tales, pitfalls, and some suggestions (not necessarily solutions) regarding crossing the science-media divide, attend this talk!
Material properties of steel in the steelpan.
Authors: Morrison Andrew C.
Published: July 2011

The Caribbean steelpan is one of the most recently developed tuned percussion instruments and has been the subject of much scientific study in recent years. The tuning of a steelpan is a complex process involving sinking the bowl of the pan, marking the note areas, heating the pan to relieve stress, and hammering notes into tune. Throughout the tuning process the material properties of the steel change measurably. After the pan is tuned, it will need periodic retuning on roughly an annual basis, depending on how often the instrument is played. A process of enriching the steel with nitrogen has been developed which increases the surface hardness of the steel significantly more than traditional methods of tuning. This nitriding process lengthens the time needed between retuning the instrument.
Materials in percussion instrument.
Authors: Kvistad Garry M.
Published: July 2011

As ideophones, the sounds of percussion instruments are very dependent on the materials of which they are made. The physical properties are important as are the methods of processing the materials that determine the dryness, temperament, and speed of sound. In this presentation, the focus will be from a performer’s point of view. The choice of mallets used to activate the instrument is as important as the instrument itself, and mallets are made of many varieties of materials as well. In addition to being a performing musician, the presenter is an instrument builder, which yields a unique relationship to the understanding of sound production. His orchestral training and instrument building experience work together, creating an understanding of how to produce different sounds with different materials and how sound is produced from a acoustical standpoint. Many different percussion instruments will be used to demonstrate the effect materials and methods of manufacturing have on the timbre of the instrument.
Wood for guitars.
Authors: Gore Trevor
Published: July 2011

Numerous famous luthiers have used low grade salvaged timber and non-wood products to demonstrate that how a guitar is designed to exploit available materials is more important than using prime tonewoods. The material properties of timber are highly variable and are not the single figures frequently quoted in reference books. Within species material properties can vary by a factor of 2. Consequently, there is significant overlap of the material properties of one species with others, implying that wood species substitution is possible with little acoustical impact if the component is designed and built to acoustical tolerances rather than dimensional tolerances. However, species selection remains a significant factor in designing guitar components, primarily for structural rather than acoustical reasons. The woods chosen have to survive long-term loading without excessive distortion over time while still allowing the radiating surfaces to vibrate freely. Important parameters include Young’s modulus, density, stability with humidity variation, heat bendability, and hardness. The author considers wood for soundboards, braces, backs, sides, necks, fretboards, and bridges. Guitars designed to acoustical criteria (rather than dimensional criteria), where the effects of different stiffnesses and densities of species are minimized, sound very similar.
Bamboo in Asian musical instruments.
Authors: Cottingham James P.
Published: July 2011

The acoustical properties of bamboo, along with its widespread availability, have made it one of the most commonly used materials for the construction of musical instruments worldwide. Among its properties important for acoustics, bamboo has a relatively low density and elastic modulus and a significant difference between the elastic moduli parallel to and perpendicular to the bamboo fibers. An extensive general review of the acoustically relevant properties of bamboo has recently been published [U. G. K. Wegst, Annu. Rev. Mater. Res. 38, 323–349 (2008)]. This paper presents some recent results on measured physical properties of bamboo as used in Asian wind and percussion instruments. The mechanical properties of the bamboo reeds used in some free reed wind instruments have been studied. Since a wide variety of flutes and reed wind instruments employ bamboo pipes the elastic moduli of bamboo pipes, as well as the non-uniformity of the pipe wall material are of current interest, in particular, as related to pipe wall vibrations. The consequences of the non-uniformity in composition and elastic modulus of quasi-cylindrical bamboo pipes are also relevant when these pipe sections are used in percussion instruments.
Case study: 1920's elementary school gymnasium to church sanctuary.
Authors: Philipp Norman H. , Coffeen Robert C.
Published: July 2011

Case study of the repurposing of Hawthorne Elementary School in Ottawa Kansas to a house of worship. The school was built and opened in 1926, served as an elementary school for 81 years, was closed in 2007, and sold to Grace Community Fellowship. The focus for this paper will be on the conversion of the existing gymnasium and attached stage platform to the main worhip space for Grace Community Fellowship. Aspects discussed include the architectural acoustics, mechanical noise control, and sound system integration.
Design of an anechoic termination for automotive applications.
Authors: Myers Kyle R. , Naghshineh Koorosh
Published: July 2011

In various automotive applications, the acoustic performance of tuning devices is assessed by measuring the transmission loss (TL) using the decomposition method [as described by Tao and Seybert (2003)]. The decomposition method, which “decomposes” the pressure wave into its incident and transmitted components, assumes an anechoic termination. However, the reliability of measurements using the decomposition method is compromised in the absence of a good anechoic termination. Thus, there is a need to accurately predict the performance of anechoic terminations. This paper constructs a finite element model in ANSYS of a typical anechoic termination consisting of a horn terminating into a pipe filled with absorbing material in order to predict the reflection coefficient across a broad range of frequencies. The model is compared to analytical predictions and experimental measurements of a prototype with similar geometry. This study could lead to further work towards optimization of horn geometry and the bodies they terminate into.
Auditory feedback from tactile interrogation of two dimensional scene for visually impaired.
Authors: Silva Pubudu Madhawa , Pappas Thrasyvoulos N. , Atkins Josh , West James
Published: July 2011

With the ever increasing availability of the internet and electronic media rich in graphical and pictorial information (for communication, commerce, entertainment, art, and education), it has been hard for the visually impaired community to keep up. We propose a non-invasive system that can be used to convey graphical and pictorial information via hearing and touch. The main idea is that the user actively explores a two-dimensional layout on a touch screen (with or without tactile overlay) with the finger while listening to spatially conditioned auditory feedback with unique sound assigned and each region representing an object. The proposed approach was successful in a range of tasks, from basic shape identification to perceiving a scene with several objects. While this can represent a revolution for the visually impaired population, sighted can also benefit from the technology in situations they are unable to utilize vision and in areas such as virtual reality, immersive environments, and medicine.
The interaction between tone and intonation in Mandarin aphasics speech.
Authors: Chiu Shang-Chen , Ogasawara Naomi , Chung Yuh-Mei
Published: July 2011

This study addresses two issues: (1) the interaction of tone and intonation in Mandarin and (2) whether nonfluent aphasic patients show the same pattern of the interaction of these two prosodic features as normal speakers do. Both tone and intonation use pitch change at different phonological levels. Intonation is superimposed on a phrase or a sentence, which must affect the pitch change of tones. In order to examine the interaction of tone and intonation, the study focuses on Mandarin disyllabic words with tone 2-2 (rising) and tone 4-4 (falling) in declarative (falling intonation) and interrogative (rising intonation) forms. An acoustic analysis tests how the F0 of the rhyme is affected by the two prosodic features. The investigation involves two groups of Taiwan Mandarin speakers: normal people and aphasic patients. The previous studies have tested non-tonic language speakers and found that the Broca’s aphasia, a nonfluent aphasia subtype, usually shows motor speech disorder, which may cause the phonetic-motoric impairment. In order to provide findings from a tonic language, this study investigates whether aphasic patients of a tone language, Mandarin, show the similar dysprosodic features.
The influence of flow model simplification on phonation onset.
Authors: Rehman Syed F. , Zhang Zhaoyan
Published: July 2011

In previous studies, phonation onset characteristics were investigated using linear stability analysis in a continuum vocal fold model. Although this approach allowed efficient calculation of phonation onset, a one-dimensional simplified glottal flow model was used in these previous studies, and it is unclear how phonation onset prediction was affected by this flow model simplification. In this study, to understand the effects of glottal flow simplification on phonation, phonation threshold pressure and onset frequency as a function of vocal fold geometry and stiffness were calculated using a two-dimensional continuum vocal fold model coupled with two-dimensional incompressible Navier–Stokes flow equations. These phonation threshold pressures and onset frequencies were compared to those predicted from a linear stability analysis of the same vocal fold model coupled with a one-dimensional glottal flow model, as in previous studies. The results show that phonation threshold pressures and onset frequencies predicted from these two approaches compared well for large glottal gaps. The difference increased as the glottal gap was constricted. Hence, the results suggest that beyond a certain glottal gap, viscous effects (except flow separation) are negligible and phonation characteristics can be predicted using a simplified and thus computationally efficient glottal flow model. [Work supported by NIH.]
Perceptual sensitivity to changes in vocal fold geometry and stiffness.
Authors: Zhang Zhaoyan , Kreiman Jody , Gerratt Bruce R.
Published: July 2011

Control of vocal quality is a primary goal of speech and the focus of clinical management of voice disorders. Therefore, it can be argued that auditory-perceptual sensitivity to the acoustic changes that occur as a laryngeal parameter is manipulated should be considered in the development of physiologic models of phonation. Listener perception of the effects of change in vocal fold geometry (medial surface thickness and vocal fold depth) and stiffness will be investigated by measuring the just-noticeable difference (JND) to acoustic stimuli generated by physical models differing in these three model parameters. The acoustic pressure produced by physical models differing in small steps in each model parameter will be recorded and normalized for F0. Listeners will hear pairs of these acoustic stimuli in a same/difference task and JNDs will be calculated for each parameter. Data will be interpreted by comparing the JND for each model parameter to the range of values for that parameter. Results will be discussed with regard to which vocal fold parameters are most important for generating perceptually relevant and thus clinically meaningful changes in quality, thus validating their inclusion in physical models of phonation. [Work supported by NIH.]
Two-dimensional speed and depth filtering applied to shallow water matched-field detection.
Authors: Pitre Ryan R. , DelBalzo Donald R. , Leclere James H.
Published: July 2011

Passive acoustic sonars have difficulty in detecting quiet sources in noisy shallow-water environments. The standard approach to improve detection is to use a large aperture linear array of horizontally distributed hydrophones and azimuthal processing to increase the signal-to-noise ratio (SNR) through beamforming. A newer approach is to exploit the acoustic interference of normal modes in shallow water and apply matched-field (model-to-data) correlation techniques to estimate source locations in depth and range using signals received on a linear vertical array. These localization techniques are not designed for detection of quiet targets and some applications preclude the use of vertical arrays. This work examines the utility of matched-field processing on linear and planar horizontal arrays on the ocean bottom in shallow water. A speed and depth filter to eliminate high-speed surface targets is applied. A track-before-detect strategy to convert matched-field localizations into source detections in various physical and acoustic environments is utilized. We search for submerged targets at constant speed, constant depth, and linearly changing depth. We show the advantages of planar compared to linear arrays to discriminate submerged from surface sources as a function of SNR. [Work sponsored by QNA.]
Integrating interactive simulations into demo sessions to help students visualize the invisible.
Authors: Adams Wendy K.
Published: July 2011

The hands-on demos included with the ASA demo-kit or “traveling road show” are excellent demonstrations of physical phenomena such as standing wave & resonance (spring, string vibrater, pitch fork, air columns, and wine glass), the force of sound (ultrasonic levitation), and spectrum analysis just to name a few. Most of these demos work with either waves that move so quickly the eye cannot follow (spring appears to be in two places at once) or sound waves in air, which are invisible leaving it up to the students to visualize on their own. Integrating in some interactive simulations such as PhET http://phet.colorado.edu could provide students with the ability to slow time while observing standing waves “Wave on a String” or see the sound waves travel from a speaker to the ear “Sound” and “Wave Interference” or see how individual harmonics (sines and cosines) can create a more complicated sound wave, “Fourier: Making Waves.” These simulations will be demonstrated along with ideas on how to fit them into a future demo show.
The vibrating string.
Authors: Hanson Helen
Published: July 2011

In this experiment, we will observe standing waves on a long elastic band. A sine wave generator will be used to make the band vibrate at different frequencies. The band will vibrate particularly well at certain frequencies, during which distinct loops will appear on the band. Observers will note the frequency that results in a single loop on the band, then the frequency that results in two loops, and so on up to five loops. The frequencies that result in these loops should be integer multiples of the single-loop frequency.
Bilateral cochlear implants in young children.
Authors: Litovsky Ruth Y.
Published: July 2011

Cochlear implants (CIs) are provided to a growing number of people who are deaf. Single CIs offer opportunity for language acquisition, but there exist remaining challenges. In normal-hearing individuals binaural hearing provides cues that are important for sound localization and speech understanding in noisy environments. Provision of bilateral CIs to many children occurs with the expectation that they will develop spatial hearing abilities. Outcomes in these children are mixed; while some are able to localize sound significantly better with bilateral CIs than with a single CI, other children demonstrate poor spatial hearing skills. Factors that seem to contribute to performance include amount of auditory deprivation prior to implantation and auditory experience following bilateral activation. Hardware/software limitations in implanted devices result in binaural cues being distorted or discarded. Studies using research processors show that these cues can be transmitted with fidelity to the patients, but that perceptual sensitivity to these cues may depend on the period of auditory deprivation that listeners have experienced. This talk will focus on progress and outcomes in children who are deaf and use bilateral CIs, with suggestions for future development that will depend on improved audio signal processing and signal delivery to the implantable devices.
Acoustic characterization of vuvuzelas.
Authors: Ruhala Richard , Cunefare Kenneth , Ortkiese Tina , Ruhala Laura
Published: July 2011

Vuvuzelas are inexpensive plastic horns that became a part of the American vocabulary during the 2010 World Cup held in South Africa. Spectators were allowed to play these horns during the game, causing major noise complaints from athletes and spectators alike, including television listeners from around the world. The vuvuzelas and similar small, plastic horns are now being sold in the US and other countries, and there is concern that they will create a related noise problem at future sporting events. Several noise measurements have been reported in the literature, but rigorous acoustical experimental methods were lacking. This work presents the measured sound power and spectra produced by several different vuvuzelas, one at a time, inside a hemianechoic chamber. A variety of volunteers have played the horns so that the measurements provide a realistic range of levels. Furthermore, a model is developed to predict noise levels within the stands and on the playing field.
Gold Medal of the Acoustical Society of America
Authors: Ungar Eric E.
Published: July 2011

The Gold Medal is presented in the spring to a member of the Society, without age limitation, for contributions to acoustics. The first Gold Medal was presented in 1954 on the occasion of the Society's Twenty-Fifth Anniversary Celebration and biennially until 1981. It is now an annual award.
Harmonization of methods-a contribution to the holistic Soundscape.
Authors: Schulte-Fortkamp Brigitte , Fiebig Andre
Published: July 2011

The Soundscape approach can provide meaningful information based on the local expertise and allows combining meaningful knowledge and diverse acoustical data about these respective environments. Qualitative methods, which are related to people’s mind belong to a heterogeneous research field. Moreover, among them are different forms of observation, interviewing techniques and the collection of documents and acoustical data. At the same time methods are used that are based on various theoretical assumptions and methodological positions. But, those approaches all share common ground and agree on certain ideas about the nature of social reality, which is shaped by social meaning. Social reality is always a meaningful reality and depends on a certain point of view or perspective and is therefore tied to social locations. Based on earlier findings, methods have been proposed for comparing sonic environments based on the physical properties and memories of such environments. When it comes to standardization, there are still many open questions how to combine the different contributors to Soundscape regarding to an analysis that takes physical and perceptive evaluation into consideration. This paper will provide an insight into the evaluation process related to the holistic in Soundscapes.
Automated analysis and interpretation of long-term soundscape audio recordings.
Authors: Maher Robert C.
Published: July 2011

Contemporary audio recording devices now provide the capability to obtain uninterrupted digital audio soundscape recordings lasting days, weeks, and months. While storage and transfer of sound file recordings of such extreme length is now possible, human listeners are generally unable to dedicate the time, effort, and cost required to review and interpret aurally all but a tiny fraction of such lengthy files. Instead, a variety of automated processing algorithms are under development to aid in the analysis and characterization of long-term soundscape studies and to present the analysis results to human listeners in an informative and perceptually meaningful manner. This paper reports on three methods for presenting long-term soundscape data: visual spectrographic display, event-based aural sampling, and time-compressed and/or time-lapse aural display.
Tracking dolphins with hydrophone arrays deployed from the floating instrument platform R/P FLIP in the Southern California Bight.
Authors: Gassmann Martin , Henderson E. Elizabeth , Roch Marie A. , Wiggins Sean M. , Hildebrand John A.
Published: July 2011

Dolphin movements were studied with hydrophone arrays and visual observations using the R/P FLIP moored North of San Clemente Island in Fall 2008. A total of 14 hydrophones distributed as two L-shaped arrays at 36 m depth and one vertical line array at 139 m depth were deployed from FLIP. The data were sampled at 192 kHz continuously for 4 weeks. Sound localizations were realized by estimating vertical and horizontal angles from automatically detected dolphin echolocation clicks and whistles to compute ranges, depths, and bearings. While angles to broadband clicks were estimated by cross-correlation, angles to narrow-band whistles were obtained by coherently frequency-averaging conventional frequency domain beamformer outputs. Sound refraction errors were corrected using Snell’s law. The localization methods were groundtruthed by successfully tracking ships and by comparing acoustic and visual positions for dolphin groups. First results reveal continuous trajectories of common dolphin schools for as long as 15 min and suggest that common dolphin actively approaches the FLIP from at least 1 km distance. Common dolphins also appear to be capable of echolocating man-made seafloor instruments at 350 m depth by diving from the surface to approximately 139 m depth while discontinuing whistling.