bluuebunny/crossref_metadata_2025 huggingface dataset:
Effects of 3-D projection on audiovisual speech perception
Authors: Whalen D. H. , Gans Richard , Fowler Carol A. , Brown Julie M.
Published: October 2013

Visual information about speech influences speech perception, leading to better perception in noise and to illusions such as the McGurk effect. Here, the question was addressed of whether visual influences would be greater with a three-dimensional visual speaker [the patented Life Imaging Projection System (L.I.P.S.)] than the two-dimensional one. Perception in noise was tested with 54 monosyllabic English words of moderate frequency. The McGurk effect was tested with acoustic words having bilabial onset consonants and visual nonwords with alveolar onsets. Visual information improved perception in noise, as found previously; the 3-D version (a videotape projected onto a life cast of the speaker’s head) elicited better performance than the 2-D. However, the 3-D version elicited fewer McGurk responses. Since the presence of noise increases visual fixation on the lips [Vatikiotis-Bateson et al., Percept. Psychophys. 60, 926–940 (1998)], it is possible that more direct information about mouth shape was available in that condition. Further, the 3-D version may have been more likely than the 2-D to engage a direct eye gaze, perhaps reducing the McGurk effect. A test is planned in which noise is added to McGurk stimuli; this may restore the advantage for the 3-D information. [Work supported by NIH grant HD-01994.]
Overview of ASIAEX field experiments in the South and East China Seas
Authors: Lynch James F. , Dahl Peter H.
Published: October 2013

In the spring of 2001 the Asian Seas International Acoustics Experiment (ASIAEX) was performed in the South and East China Seas. The ASIAEX program originated from the Office of Naval Research’s initiative to develop a Sino-American cooperation in the field of ocean acoustics, and expanded to involve Taiwan, Korea, Singapore, and Japan. In the South China Sea, the emphasis was on lower frequency (50–600 Hz) acoustic propagation through complex oceanography along and across the shelfbreak. The oceanographic variability was driven at the mesoscale by the monsoonal wind stress, buoyancy fluxes from the Chinese coast, and by occasional Kuroshio intrusions through the Luzon Strait. Large, nonlinear internal waves also significantly affected the acoustics. In the East China Sea the emphasis was on low- to- midfrequency acoustic interaction with, and reverberation from, the sea floor and sea surface. The experimental site was chosen for flatness, to minimize the influence of bathymetric trends, and emphasize bottom roughness and subbottom structures, in the measurements. This talk will describe the scope of the ASIAEX experimental program, including the ocean acoustic and environmental characterization of the seafloor, sea surface, and water column. Results from various measurement programs will be described in separate papers.
Direct path fluctuations due to shallow-water variability
Authors: Karpi Stephen , Smith Kevin B. , Ramp Steven , Dahl Peter H.
Published: October 2013

The current interest in enhancing the forecasting capabilities of both active and passive sonar systems employed in littoral regions has greatly escalated. This requires improvements in the general understanding of the influence of shallow-water internal waves on acoustic propagation. This work will contribute to a more fundamental understanding of ocean acoustic propagation and fluctuations in shallow-water regions and examine the influence of shallow-water variability on the relatively short-range waterborne propagation paths. Specifically, internal wave fluctuations will be considered and the influence on the acoustic propagation will be quantified in terms of spatial (vertical) coherence functions. The data to be examined will be generated numerically based on an acoustic propagation model employing environmental data taken from the East China Sea as part of the ONR-sponsored ASIAEX experiments. The results of this analysis will be compared with the measured data currently being analyzed at the Applied Physics Laboratory at the University of Washington.
The measurement of acoustic dispersion in loosely consolidated, saturated sediments using a water-filled impedance tube
Authors: Wilson Preston S. , Park Eun-Joo , Roy Ronald A. , Carey William M.
Published: October 2013

At frequencies of several kilohertz and below, the measurement of sound propagation in marine sediments is difficult due to the larger wavelengths. Laboratory experiments can be limited by the size of the facility required for propagation studies but are amenable to material property measurements. Impedance tube techniques can be used to measure the complex interfacial properties of small samples over a broad and continuous range of frequencies. From this, frequency-dependent sound speed and attenuation is obtained. Results from compressional wave speed and attenuation measurements made with a laboratory impedance tube using artificial and natural water-saturated sediments will be presented and compared to existing propagation models. Variation of attenuation with frequency will be discussed. [Work supported by the U.S. Navy Office of Naval Research and the Coastal Systems Station.]
Acoustical differences between pre-Columbian Mexican aerophones
Authors: Arias J. Guillermo Contreras
Published: October 2013

This paper discusses Mesoamerican musical instruments that produce special sounds and noises. The types of musical instruments to be discussed and demonstrated include those that (a) produce animal sounds; (b) allow performers to exploit multiphonic and beat effects; and (c) allow performers to produce microtonal and polyphonic effects. Examples are shown of simple flutes, vessel flutes, and whistles of Aztec, Mixtec, Mayan, Olmec, and other pre-Colombian cultures. (To be presented in Spanish.)
Musical instruments from the Mayan culture
Authors: Rizo Isabel Elena Romero , Redondo Jose de Jesus Negrete , Paulin Pablo Roberto Lizana
Published: October 2013

This research work presents different kinds of sound generation instruments from the Mayan culture together with the Pablo Castellanos and Arturo Chamorro classification. It has to be noted that most of these musical instruments, whistles and noise generators are lost and some of them can only be seen on codex and museums. (To be presented in Spanish.)
Ultrasound detection and computer segmentation of high intensity focused ultrasound (HIFU) lesions
Authors: Owen Neil R. , Bailey Michael R. , Kim Yongmin , Crum Lawrence A.
Published: October 2013

High intensity focused ultrasound (HIFU) can necrose tumors or cauterize tissue bleeds at intensities on the order of 1000 w/cm2. A synchronized HIFU and B-mode ultrasound system reveals a hyperechoic region at the treatment site, which grows with treatment duration and intensity. Our goal was to segment the hyperechoic region representing the lesion via image analysis and measure the ratio of its major and minor axes. Our algorithm uses the RF data as input, processes it, and outputs a binary image that represents the lesions cross-sectional profile. With depth settings from the clinical ultrasound imager, it is possible to calculate lesion dimensions from the binary image. The algorithm was tested with lesions made in a transparent polyacrylamide tissue phantom that became opaque in response to focal heating during HIFU exposure. Lesion size was recorded simultaneously with ultrasound and a CCD camera, and both measurements agreed well. Additionally, computer segmentation agreed well with segmentation by HIFU users blinded to the experimental conditions. The average difference of the determined ratio was 13% for lesions less than 0.5 cm in length. Thus, it is possible to localize precisely the treated tissue region. [Work supported by NSBRI, NSF, and NIH-SBIR.]
A needle-size hydrophone and thermocouple for high-intensity focused ultrasound
Authors: Vaezy Shahram , Wyzgala Mark , Keilman George
Published: October 2013

Thermal and acoustic measurements at high acoustic intensities are desirable in studies involving high-intensity focused ultrasound (HIFU). We are developing a needle-size probe comprised of a hydrophone and a thermocouple, that can withstand high-intensity fields without damage. The probe can simultaneously map the acoustic pressure and temperature field in a test medium. The hydrophone will be nominally 25-m PVDF or PVDF-TrFE with thin-file electrodes, with a flat frequency response from 1 to 20 MHz, isolated from the metallic needle by an ultrasound-absorbing lossy polymer material. The thermocouple (accurate within 1C) signals will be rf-isolated from the hydrophone signals and electromagnetic interference originating from the HIFU source transducer, allowing rapid temperature rise measurements (250 readings per second) to be made with minimal noise and interference. A conformational coating will protect the hydrophone and the thermocouple from cavitation at high acoustic intensities of 4000 W/cm2. The complete assembly will be integrated into a 13-gauge (0.24-mm o. d.) needle (150 mm long). The results of the manufacturing, characterization, and testing in novel, protein-based tissue-mimicking phantoms will be presented. [Work supported by NIH, NSF.]
Constrast enhancement in harmonic imaging using time reversal processing
Authors: Tanter Mickael , Gauthier Thomas , Barriere Christophe , Fink Mathias
Published: October 2013

Harmonic imaging coupled to the use of contrast agents has become a topic of wide interest in ultrasonic medical imaging. Instead of achieving images at the fundamental frequency of the emission signals, images are built at twice the excitation frequency that corresponds to the resonance frequency of the bubbles embedded in the medium. Consequently, the contrast becomes important between areas of low and high concentration of bubbles. However, at a high mechanical index, the harmonic components of backscattered echoes depends on the intrinsic nonlinear properties of tissues as well as the bubble’s resonance. The focused beam is generating harmonics during its nonlinear propagation. It results in a degradation of the harmonic image contrast. Time reversal is an elegant way to find the emission codes allowing us to cancel the harmonic components due to nonlinear propagation of the ultrasonic beam and so to recover an optimal image contrast. Indeed, the wave equation in a nonlinear regime remains time reversal invariant: in the absence of bubbles, if the backscattered echoes are time-reversed and reemitted by the array, the harmonic components of the resulting wavefront are transferred back to the fundamental frequency during propagation. Experiments conducted with 1-D-linear arrays illustrate this cancellation technique.
Mie scattering off coated microbubbles
Authors: Nelissen Radboud , Koene Elmer , Hilgenfeldt Sascha , Versluis Michel
Published: October 2013

The acoustic behavior of coated microbubbles depends on parameters of the shell coating, which are in turn dependent on bubble size. More intimate knowledge of this size dependence is required for an improved modeling of a distribution of coated microbubbles such as found in ultrasound contrast agents (UCA). Here a setup is designed to simultaneously measure the optical and acoustic response of an ultrasound-driven single bubble contained in a capillary or levitated by the pressure field of a focused transducer. Optical detection is done by Mie scattering through an inverted microscope. Acoustical detection of the single bubble by a receiving transducer is made possible because of the large working distance of the microscope. For Mie scattering investigation of excited bubbles, two regimes can be distinguished, which require different detection techniques: Conventional wide-angle detection through the microscope objective is sufficient for bubbles of radius exceeding 10 μm. For smaller bubbles, two narrow-aperture detectors are used to reconstruct the bubble dynamics from the complex angle-dependence of the scattered light.
High-speed optical imaging of microbubble dynamics at 40 ns time scale
Authors: Versluis Michel , Chin Chien Ting , de Jong Nico
Published: October 2013

The interactions between ultrasound and microbubble contrast agents, such as nonlinear oscillations, acoustic disruptions, and destruction of microbubbles, are exploited in diagnostic methods such as harmonic imaging and triggered imaging, as well as emerging therapeutic techniques such as controlled drug delivery. Optical visualization at the microsecond to nanosecond time scale has the potential to elucidate such interactions. However, these recordings are limited by image resolution, frame rate, total number of frames, and light sensitivity. We have constructed a digital ultra-high-speed camera system, named Brandaris 128, by combining the flexibility of highly sensitive CCDs with the high number of frames available in rotating mirror cameras. In a standard run our camera records 6 full sequences of 128 digital images at a frame rate of 25 million frames per second. The high number of frames allows for the monitoring of acoustic disruptions and nonlinear oscillations of a single contrast agent microbubble under consecutive diagnostic ultrasound pulses at various amplitudes applied to the same bubble. In this way the contribution of each individual bubble to the acoustic response can be measured, which is essential for further optimization of contrast agents and ultrasound detection methods.
The effect of envelope pattern on the impression of sound quality
Authors: Kuwano Sonoko , Namba Seiichiro
Published: October 2013

Since the 1970’s the present authors have conducted a series of experiments on the effect of envelope patterns on a subjective impression of sounds and a model of dynamic hearing characteristics was proposed on the basis of the results of these experiments. The present investigation was designed to examine the effect of envelope pattern on the impression of sound quality. Three kinds of envelope pattern were used; they were sounds with short rise time and long decay, sounds with long rise time and short decay, and steady state sounds. The duration of each sound was 125, 250, and 500 ms. In total, nine kinds of sound were prepared. The sound was repeated with silent intervals and the total duration was 5 sec. The sound quality was judged using a semantic differential and a paired comparison. It was found that the envelope pattern has a significant effect on the impression of pleasantness and the duration of the sound on the impression of sharpness and articulation.
Frequency-domain methods for modeling a nonlinear acoustic orifice
Authors: Egolf David P. , Murphy William J. , Franks John R. , Kirlin R. Lynn
Published: October 2013

This presentation describes frequency-domain methods for simulating transmission loss across a single orifice mounted in an acoustic waveguide. The work was a preamble to research involving earplugs containing one or more orifices. Simulation methods included direct Fourier transformation, linearization about an operating point, and Volterra series. They were applied to an electric-circuit analog of the acoustic system containing the orifice. The orifice itself was characterized by an empirical expression for nonlinear impedance obtained by fitting curves to experimental resistance and reactance data reported by other authors. Their data-collection procedures required the impedance expression presented herein to be properly labeled as a describing function, a quantity well known in the nonlinear control systems literature. Results of the computer simulations were compared to experimental transmission-loss data. For a single-tone input sound pressure, the computer code accurately predicted the output fundamental (i.e., without harmonics). For a broadband input, the simulated output was less accurate, but acceptable. Levels of the sound-pressure input ranged from 60 to 160 dB. [Work supported by the National Institute for Occupational Safety and Health, Cincinnati, OH, through a research associateship granted the first author by the National Research Council.] a)Currently on leave at National Institute for Occupational Safety and Health, Cincinnati, OH.
Experimental investigation of sound absorbers based on microperforated panels
Authors: Vechiatti Nilda S. , Mendez Antonio M. , Gimenez de Paz Juan C.
Published: October 2013

Microperforated panels have been studied as a good, interesting absorbing element. In previous papers the properties of high absorption obtained in a wide frequency band was demonstrated, based on the impedance of the very small perforations. The perforation area ratio, the diameter of the holes, the thickness of the panel, and the density and viscosity of the air are the terms that define the sound absorption provided by the element. The microperforated panels have a simple structure and it is possible to build single or double resonators, in order to obtain a wide band response. An orifice may be considered as a short tube. Many years ago, Rayleigh and Crandall studied the propagation of sound in small tubes, of a very short length compared to wavelength. They found a high acoustics resistance and a very small reactance. So, the microperforated panel can be used as a dissipative element. An experimental investigation was carried out on different samples of microperforated panels, in order to obtain their sound absorption coefficient and so verify the validity of the mathematical models. Microperforated panels have been developed to cover a welding cabin internally, where classical absorbents are useless. (To be presented in Spanish.)
Urban noise pollution in the city of Curitiba, Brazil
Authors: Zannin Paulo H. T. , Diniz Fabiano B.
Published: October 2013

This paper presents the results obtained from a study on environmental noise pollution in the city of Curitiba, Brazil. The equivalent sound-level values LAeq, 2 h were measured and tabulated for 1000 locations spread over the urban zones of the city of Curitiba in several urban zones: residential, mixed, services, downtown, and industrial. It was found that 93.3% out of the surveyed locations display during the day equivalent sound levels over 65 dB(A), and 40.3% out of the total number of locations measured during the day display extremely high values of equivalent sound levels: over 75 dB(A). The average noise levels per zone has ranged from 73.4 to 78.1 dB(A). (To be presented in Portuguese.)
Noise levels at critical points in the municipality of Guadalajara, Jalisco, Mexico
Authors: Figueroa Arturo , Garcia Jesus , Macias Jorge , Orozco Martha , Garcia Javier , Delgadillo Alan
Published: October 2013

Studies of acoustic conditions are planning tools on which we can diagnose the problem of noise pollution in the cities. The first study on noise pollution made in the city was made by the University of Guadalajara in 1995 and updated in 1998 covering with measuring points the city center. This paper discusses the problem of noise pollution by motor vehicles at critical points and covers a total of 105 points. The study also analyzes the problem of noise pollution base on the community annoyance from which a regulation policy should derive. Results of the study show that the most critical points are located within zone 1 (center) where Leq levels within the range of 70–85 dB were found. Such levels exceed by far the international standard of 65 dB as recommended for ambient noise by the World Health Organization.
Noise barrier for the Temuco ByPass Highway
Authors: Gerard Christian , Campos Aldo , Belfiore Sergio
Published: October 2013

Increases in traffic and the emergent Highway Concession Program created by the Public Works Ministry of the Chilean government, have led to the necessity of providing acoustic protection in inhabited areas in which the level of noise exceeds that allowed by the standard. Around the world, the installation of acoustic barriers has been one of the main measures of the controlling traffic noise. This is the case with the Temuco ByPass Highway, an extension of 21 km, located in a rural area typical of the environment and landscape of the South of Chile. A total of 6000 lineal meters of transparent acoustic barrier (Methacrylate) was installed. This barrier is the first one of its type to be installed in South America, and theoretical calculations and practical results are analyzed in this work. (To be presented in Spanish.)
Absorption characteristics of porous media: A model for traffic-noise reducing asphalt
Authors: Tavossi Hasson M.
Published: October 2013

This paper presents preliminary investigation into the feasibility of the use of granular materials, with special grain size distribution as the asphalt constituents, for selective absorption of traffic-noise—generated by the engine and tires-asphalt-interactions—of the roads and highways passing near residential areas. The near-term goal of this research is laboratory data collection and modeling on the sound absorption properties of asphalt model-media, selecting media with required absorption properties, and analysis of their traffic-noise absorption characteristics. Long-term efforts are aimed at the general reduction of traffic-noise reflected from the surfaces of these highways by selective absorption of noise of different frequency bands in the granular constituents of asphalt. Reducing noise from the road surfaces by selective sound absorption at the surface results in lowering of the noise level pollution of the streets in the residential areas and the communities situated close to highways.
Analysis of a pollution problem of ambient noise and bases for a municipality inspection in the center of Talquepaque, Jalisco, Mexico, 2001
Authors: Rodriguez Erika , Orozco Martha , Palafox Lourdes
Published: October 2013

The city of Tlaquepaque is delimited at the north by Guadalajara city, at the west side by Zapopan, at the south side by Tlajomulco and El Salto, and in its east side by Tonala. Our purpose in this study is to create the first noise map of Tlaquepaque, being the study area between the streets: Avenida Ninos Heroes, Revolucion, Florida, and Marcos Montero. We take 53 points of which 77.3% are above 65 dBA, the Leq average of the points was 69.7 dBA, having as a minium 44.8 dBA and as a maximum 108.6 dBA. Nowadays Tlaquepaque does not have any noise map, so we are trying to identify its more complex areas. The high dB levels found in the study show us how high the noise in the street is, and this is reflected by several citizen complaints about noise received by the municipality. Because of this it is necessary to have an ambient noise diagnostic program, and do the necessary modifications to the current inspection and monitoring system. The preliminary results of this first noise map show a really serious problem with ambient noise caused by vehicular traffic, bad urbanization, and the existence of commercial centers that raise the ambient noise.
Sound pollution in schools nearby highways crossing Buenos Aires City
Authors: Gavinowich Daniel S. , Ruffa Francisco , Barkasz Erica A. , Ciccarella Pablo R.
Published: October 2013

According to an agreement between the concessionary company of the highways crossing Buenos Aires City (AUSA) and the School of Engineering of The Buenos Aires University, measurements of the sound level were made in the neighborhood of primary schools and high schools near the roads. The purpose of this work was to supply registered values to be able to obtain a general knowledge of sound levels ‘‘in front of’’ and ‘‘inside’’ schools, as reliably as possible. Relying on the previous measurements of some points, the registered values can be compared with the previous ones and possible changes of the sound level produced in the last times can also be estimated. Finally, the work was completed with the study of possibility of acoustic attenuation using noise barriers in critical areas because of high levels of pollution.
Global infrasound monitoring—Research issues
Authors: Bass Henry E. , Gilbert Kenneth , Garces Milton , Hetzer Claus , Herrin Gene , Golden Paul , Olson John , Osborne Daniel , Szuberla Curt A. L. , Wilson Charles , Berger Jon , Hedlin Michael , Whitaker Rod , Revelle Doug , Woodward Bob , North Bob , Kromer Richard
Published: October 2013

The International Monitoring System being installed to support monitoring compliance with the Comprehensive Nuclear Test Ban Treaty provides scientists with a unique opportunity for research. There are still a number of problems which limit the full exploitation of the system. These include limitations on signal-to-noise imposed by wind noise and the absence of well defined, internationally accepted calibration standards for sensors. But perhaps the major research challenges lie in the area of source characterization and definition. Most of the signals recorded at the few sites now operating come from unidentified sources. There has been some effort devoted to identifying local and regional sources but the unidentified category still exceeds 50% of all distinct events. There are a number of infrasound sources that occur naturally. These include volcanic eruptions, bolides, microbaroms, mountaintop/wind interactions, severe storms, and earthquakes. Manmade sources include most any energetic activity. After sorting out all these sources, there may remain more exotic sources of infrasound not yet identified. Therein lies a major source of excitement.
Evaluation of rosette infrasonic noise-reducing spatial filters
Authors: Hedlin Michael A. H. , Alcoverro Benoit , D’Spain Gerald
Published: October 2013

The spatial noise filter currently preferred for use at the new International Monitoring System (IMS) infrasound array sites consists of an array of low-impedance inlets connected by solid tubes to a microbarometer. We present results from recent tests of ‘‘rosette’’ infrasonic noise-reducing spatial filters at the Pinon Flat Infrasound test-bed in southern California. At wind speeds up to 5.5 m/s, the 96 inlet 18-m rosette filter reduces wind noise levels above 0.2 Hz by 15–20 dB. Under the same conditions, the 144 inlet 70-m rosette filter provides noise reduction of up to 15–20 dB between 0.02 and 0.7 Hz. Standing wave resonance inside the 70-m filter degrades the reception of acoustic signals above 0.7 Hz. Synthetics accurately reproduce the noise reduction and resonance observed in the 70-m filter at all wind speeds above 1.25 m/s. Experiments with impedance matching capillaries indicate that internal resonance in the rosette filters can be removed. Rosette filters are tuned to vertically incident energy. Attenuation of signals by the 70-m rosette filter at frequencies above 3.5 Hz arriving at grazing angles of <15 deg from the horizontal are predicted to range upward from 10 dB to total cancellation at 5 Hz.
An optical fiber infrasound sensor
Authors: Zumberge Mark A. , Berger Jonathan , Hedlin Michael A. H.
Published: October 2013

A new sensor for detecting infrasonic signals from distant sources has been designed, tested, and deployed. The instrument consists of a long (of order 100 m), compliant, tubular diaphragm tightly wrapped with optical fibers. The air-filled diaphragm is sealed from the ambient atmosphere and therefore expands and contracts radially along its length as the pressure changes. An optical system monitors minute variations in the optical path length of the fibers, which change as the tube expands and contracts. The new instrument responds to the spatially integrated pressure average along its length. As it relies on optical interferometry, it does not suffer from the propagation delays inherent to mechanical noise filters and as a result can be made very long. Above 1 Hz, the optical fiber infrasound sensor (OFIS) is less noisy than sensors relying on mechanical filters. The records collected from an 89 m long sensor indicate a new low noise limit in the band from 1 Hz to 10 Hz. Current research focuses on the relationship between sensor length and wind-induced noise, on the utility of the sensor as a directional infrasound antenna, and on the sensor’s performance at audio frequencies.
Co-located atmospheric infrasonic and seismic recordings of rocket launches
Authors: D’Spain Gerald L. , Hedlin Michael A. H. , Orcutt John A. , Kuperman William A. , de Groot-Hedlin Catherine , Rovner Galina L. , Berger Lewis P.
Published: October 2013

Atmospheric infrasound data and co-located, three-component seismic data have been collected by the eight microbarometers of the International Monitoring System (IMS) station and the IRIS seismic station at Pinon Flat (PFO) plus five additional microbarometer/space filter systems at five Anza seismic stations located within 40-km range of PFO in Southern California. Characteristics of the infrasound and seismic recordings from this large-horizontal-aperture array of signals from 400-km-distant rocket launches at Vandenberg Air Force Base are analyzed using waveguide invariant theory. The Navy standard Gaussian Ray Bundle (GRAB) underwater acoustic propagation code (with slight modifications), along with launch trajectory information and atmospheric data collected at the time of the launches, is used to to examine the predictability of the signal arrival structure. The predictions take into account the signal-distorting effects caused by phase delays across the spatial aperture of the space filters, which cause each infrasound array element to be directional over the frequency band of interest. [Work supported by the Defense Threat Reduction Agency.]
Long-range infrasound propagation modeling using updated atmospheric characterizations
Authors: Gibson Robert G. , Norris David E.
Published: October 2013

Infrasonic waves can propagate thousands of kilometers in range and sample regions of the atmosphere from the ground up to and including the thermosphere. Conventional infrasound propagation modeling techniques rely on climatological models of mean temperatures and winds to characterize the environment. However, temperature and wind vary over temporal and spatial scales that are not captured by climatological models. Recent work addresses the integration of infrasound propagation models, such as three-dimensional ray tracing, with numerical weather prediction models, such as the Navy Operational Global Atmospheric Prediction System (NOGAPS). Propagation results are computed using both climatological and updated atmospheric characterizations, and comparisons are presented. Implications for global infrasound monitoring are discussed. [Work supported by the Defense Threat Reduction Agency.]
Iterative solution techniques for boundary element method (BEM) equations
Authors: Marburg Steffen , Schneider Stefan , Hardtke Has-Juergen
Published: October 2013

Boundary-element discretization of the Kirchhoff-Helmholtz integral equation gives rise to a linear system of equations. This system may be solved directly or iteratively. Application of direct solvers is quite common but turns out to be inefficient for large scale problems with 10000 unknowns and more. These systems can be solved on behalf of iterative methods. This paper is dedicated to testing performance of four iterative solvers being the Restarted Bi-Conjugate Gradient Stabilized algorithm (RBiCGStab), the Conjugate Gradient method applied to the normal equations (CGNR), the Generalized Minimal Residual (GMRes), and the Transpose Free Quasi Minimal Residual (TFQMR). For that, it is distinguished between internal and external problems. Performance of iterative solvers is investigated with respect to different parameters. It turns out that sophisticated preconditioning is required for the hyper- singular external Burton and Miller formulation of nonsmooth meshes.
Transmission loss across a rectangular partition or aperture
Authors: Fox Colin , Chung Hyuck
Published: October 2013

We give closed-form solutions for sound propagation through a rectangular aperture, or plate, in a finite or infinite acoustically opaque barrier. This model is useful in descibing airborne excitation and reradiation through window openings or through floor/wall partitions that can be modeled in terms of bending stiffness and mass. While mode-matching solutions are routinely available for these problems, we are not aware of any previous analytic solutions. The value of the closed-form solution, other than the obvious ease of calculation, is in establishing scaling laws for the various regimes of structure-borne and air-borne sound. We derive the analytic solution using an extension of the Wiener–Hopf technique as applied to sound propagation in ducts with a partial rigid barrier.
Development of the Hearing In Noise Test (HINT) in Spanish
Authors: Soli Sigfrid D. , Vermiglio Andrew , Wen Karen , Filesari Carolina Abdala
Published: October 2013

Assessment of functional hearing ability is relevant to clinical outcome assessments, occupational health evaluations, and forensic applications. Communication with spoken language is a primary aspect of functional hearing ability. Comparable speech tests in multiple languages are required to make these assessments in a multilingual population. This presentation will report on an ongoing international research project to develop a Latin American Spanish version of the Hearing In Noise Test (HINT) for this purpose. The methods of selecting speech materials, recording the materials, synthesizing appropriate masking noise, equating the difficulty of the materials, forming sentence lists, norming the lists, and determining reliability and sensitivity will be discussed. Samples of Spanish, as well as other languages (English, Japanese, Mandarin, Cantonese, and Canadian French) will be used to demonstrate the procedures by which standard dialects of each language were selected. Cross-language comparisons of the spectral and temporal characteristics of the speech materials will be presented. Norms, reliability coefficients, and measurement errors for each language will also be reported. Methods for comparing and/or equating functional hearing ability across languages will be described. Finally, procedures for measuring functional hearing ability will be discussed.
Other-perception, self-perception and production of English phonemes by adult speakers of Spanish
Authors: Hanlon Ellie
Published: October 2013

A causal model of second-language production was tested. It was hypothesized that correct production results from accurate perception of unfamiliar second language (L2) phonemes when spoken by others (other-perception) and the learner (self-perception). For the correct production to develop, the learner must form new phonetic categories for the novel L2 phonemes by listening to and observing native speakers. The categories are then used by the learner as an internal standard against which to judge production attempts. The participants’ production was measured by recording a nonword syllable reading task. Self-perception was measured by asking participants to listen to their recordings and identify phonemes using a two-alternative forced choice format. Other-perception was measured the same way as self-perception except the stimuli were recorded by a native English speaker. The path analysis shows the squared multiple correlation coefficient for production when other-perception and self-perception are used as predictors is 0.83 (83% of the variance in production is accounted for by other- and self-perception). However, the relationship between other-perception and production is nonsignificant when controlling for the effects of self-perception. This suggests that learners are developing an internal standard through other-perception skill and using this standard to adjust their attempts at pronouncing novel L2 phonemes.
Does difficulty perceiving American English /r/ and /l/ affect Japanese listeners’ lexical confusion of these phonemes?
Authors: Komaki Ryo
Published: October 2013

Phonetic environment has proven to be one of the most important factors affecting non-native English speakers’ perception of American English /r/ and /l/ [e.g., Lively et al., J. Acoust. Soc. Am. 96, 2076–2087 (1994)]. In the present study native Japanese speakers’ lexical confusion of English /r/ and /l/ are examined through a word translation experiment which employed pairs of English words minimally contrasting /r/ and /l/ in various word positions. Results indicate that English words in which the /r/ or /l/ is located in a perceptually difficult to identify position (e.g., initial consonant cluster: ‘‘branch’’ versus ‘‘blanch’’) are more likely to be mistranslated than those in which the phoneme is located in an easy to identify position (e.g., final singleton: ‘‘compare’’ versus ‘‘compel’’). This finding suggests that errors in phoneme perception and lexical confusion might be related. Pedagogical implications for second language learning will be discussed with respect to results from both learning and retention experiments. [Work supported by TAO, Japan.]
Native and non-native perception of phonemic length contrasts in Japanese: Effect of identification training and exposure
Authors: Tajima Keiichi , Rothwell Amanda , Munhall K. G.
Published: October 2013

Japanese distinguishes between words by the presence or absence of several types of mora phonemes, often realized as a contrast in segment duration, e.g., /hato/ (pigeon) versus /hat:o/ (hat). Several studies suggest that such contrasts are difficult for English listeners to perceive [e.g., R. Oguma, in Japanese-Language Education Around the Globe, 2000, Vol. 10, pp. 43–55]. In this study we investigated the effect on the perceptual ability of both Japanese exposure and perceptual identification training. Three groups of subjects were tested: (1) English speakers with no Japanese experience; (2) English speakers who had spent 1–6 months in Japan; and (3) native Japanese speakers. Subjects participated in a forced-choice identification task in which they heard words and nonwords produced by Japanese speakers and identified which word they heard by choosing among items that minimally differed with respect to these contrasts. Additionally, subjects in the second group underwent five days of perceptual training during which they received immediate feedback, repeating trials until they responded correctly. Results suggest that although the overall performance was relatively high, identification accuracy improved with exposure to Japanese and with perceptual identification training. Implications of this work on theories of second-language learning will be discussed. [Work supported by TAO, Japan.]
Deconvolution and signal extraction in geophysics and acoustics
Authors: Sibul Leon H. , Roan Michael J. , Erling Josh
Published: October 2013

Deconvolution and signal extraction are fundamental signal processing techniques in geophysics and acoustics. An introductory overview of the standard second-order methods and minimum entropy deconvolution is presented. Limitations of the second-order methods are discussed and the need for more general methods is established. The minimum entropy deconvolution (MED), as proposed by Wiggins in 1977, is a technique for the deconvolution of seismic signals that overcomes limitations of the second-order method of deconvolution. The unifying conceptual framework MED, as presented in the Donoho’s classical paper (1981) is discussed. The basic assumption of MED is that input signals to the forward filter are independent, identically distributed non-Gaussian random processes. A forward convolution filter ‘‘makes’’ the output of the forward filter more Gaussian which increases its entropy. The minimization of entropy restores the original non-Gaussian input. We also give an overview of recent developments in blind deconvolution (BDC), blind source separation (BSS), and blind signal extraction (BSE). The recent research in these areas uses information theoretic (IT) criteria (entropy, mutual information, K–L divergence, etc.) for optimization objective functions. Gradients of these objective functions are nonlinear functions, resulting in nonlinear algorithms. Some of the recursive algorithms for nonlinear optimization are reviewed.
Bayesian probability analysis for acoustic–seismic landmine detection
Authors: Xiang Ning , Sabatier James M. , Goggans Paul M.
Published: October 2013

Landmines buried in the subsurface induce distinct changes in the seismic vibration of the ground surface when an acoustic source insonifies the ground. A scanning laser Doppler vibrometer (SLDV) senses the acoustically-induced seismic vibration of the ground surface in a noncontact, remote manner. The SLDV-based acoustic-to-seismic coupling technology exhibits significant advantages over conventional sensors due to its capability for detecting both metal and nonmetal mines and its stand-off distance. The seismic vibration data scanned from the SLDV are preprocessed to form images. The detection of landmines relies primarily on an analysis of the target amplitude, size, shape, and frequency range. A parametric model has been established [Xiang and Sabatier, J. Acoust. Soc. Am. 110, 2740 (2001)] to describe the amplified surface vibration velocity induced by buried landmines within an appropriate frequency range. This model incorporates vibrational amplitude, size, position of landmines, and the background amplitude into a model-based analysis process in which Bayesian target detection and parameter estimation have been applied. Based on recent field measurement results, the landmine detection procedure within a Bayesian framework will be discussed. [Work supported by the United States Army Communications–Electronics Command, Night Vision and Electronic Sensors Directorate.]
Coupled mode propagation in an elastic oceanic wedge
Authors: Abawi Ahmad T.
Published: October 2013

The elastic version of the one-way coupled mode propagation model [Abawi, J. Acoust. Soc. Am. 111, 160–167 (2002)] is used to compute the propagation of waves in an ocean overlaying a shear-supporting wedge-shaped bottom. The range-dependent ocean is approximated by a set of stair-step elastic waveguides. The elastic modes are obtained from the solution of the equations of motion in each stair-step and the solution of the range-dependent problem is obtained by solving a set of coupled differential equations for the mode amplitudes as a function of range. Various field quantities such as the scalar and shear potentials, the compressional and shear pressures, and the displacements are computed and the results are compared with those obtained from the fast field propagation model, OASES.
Solving the diffusion equation with a finite element solver: Calculation of diffuse sound field in room acoustics
Authors: Valeau Vincent , Sakout Anas , Li Feng , Picaut Judicael
Published: October 2013

Over the last years, some publications [e.g., Picaut, Simon, and Hardy, J. Acoust. Soc. Am. 106, 2638–2645 (1999)] showed that the acoustic energy density in closed or semiclosed spaces is the solution of a diffusion equation. This approach allows the nonuniform repartition of energy, and is especially relevant in room acoustics for complex spaces or long rooms. In this work, the 3-D diffusion equation is solved directly by using a finite element solver, for a set of long rooms and absorbing rooms. The stationary equation is first solved. A constant-power acoustic source is modelized by setting appropriate boundary conditions. The time-dependent problem is also solved to simulate the sound decay, with an impulse source defined in a subregion with relevant initial conditions. Results concerning sound attenuation and reverberation times match satisfactorily with other theoretical and numerical models. An application is also given for two coupled rooms.
Reverberation time measurement of a structure or a room using modified wavelet transform
Authors: Lee Sang-Kwon , Park Jin-Ho
Published: October 2013

In structure damping or acoustic decay measurement using the third-octave band pass filter, there is inevitable experiment error produced by ringing at the tail part of the impulse response of the filter. This ringing gives rise to the distortion of the decay curve. To reduce this error, it has been recommended that the product of the 3 dB bandwidth B of the filter and the reverberation time T of the system is at least 16. In case of a system having a short reverberation time the decay curve cannot be measured reliably using the filter. In this paper, the modified wavelet transform (MWT) has been proposed to determine accurately the decay curve with a low value of BT. The MWT decomposes the decay signal of a system into time–frequency domain using the third-octave band wavelet filter bank. When the MWT is applied to the measurement of the decay curve, it is found that the requirement BT<16 can be replaced by the replacement BT<4. It was applied to the reverberation time measurement of a small room and the identification of impact location occurred by a loose part in the nuclear power plant. [Work supported by Nuclear Research Project in Korea.]
Calculating room acoustic parameters from pseudo-impulsive acoustic sources
Authors: San Martin Maria L. , Vela Antonio , San Martin Ricardo , Arana Miguel A.
Published: October 2013

The impulse response function provides complete information to predict the acoustic response of a room to an acoustic input of arbitrary characteristics. At this job study, small explosions of firecrackers are proposed to be used as pseudo-impulsive acoustics sources to determine some acoustic parameters of a room such as reverberation time, definition, and clarity, comparing these results to those obtained with other techniques. A previous characterization of these sources allows us to state that they can be used for this purpose because they are, in practice, omnidirectional, their temporary pattern is highly repetitive and their spectral power is, as well, repetitive and with enough power in octave bands from 125 Hz to 8 kHz. If the linear time-invariant system impulse response h(t) is known, output signal s(t) regarding any arbitrary signal s(t) can be obtained. For our pseudo-impulsive sources, the output signal s(t) has been taken as impulse response h(t). Using the integrated impulse response method suggested by Schroeder, it has been stated that both the mean values and standard deviations for some parameters are practically identical to results obtained with other usual techniques. (To be presented in Spanish.)
Acoustic surveys of humpback whales: Calibration experiments off the east coast of Australia
Authors: Noad Michael J. , Cato Douglas H.
Published: October 2013

Male humpback whales are frequently heard singing during migration and on their breeding grounds, often continuously for many hours, and the sounds are audible for tens of kilometers. Acoustic surveying may be useful in quantifying whale movements in oceanic waters beyond the range of land surveying, and it might also be a useful addition to visual monitoring in areas where this is possible. For acoustic surveys to be of use, the acoustic cues of the whales must be quantified and calibrated against the numbers of whales in an area. A combined visual and acoustic survey of whales migrating close to shore was conducted off the coast of southeast Queensland. Song activity, measured using two indices, correlated significantly with the number of passing whales determined visually. Linear regressions of daily measures of song activity with numbers of whales seen lead to estimates of ratios of singers with whales seen at 0.127±0.027 (95% confidence interval) and singer hours with whales seen at 0.288±0.065. The possible use of these indices for conducting stand-alone acoustic surveys will be discussed.