bluuebunny/crossref_metadata_2025 huggingface dataset:
Recent developments in statistical energy analysis for aircraft interior noise
Authors: Bremner Paul , Bloor Michael , Wilby John F.
Published: October 2013

Price and Crocker [J. Acoust. Soc. Am. 47 (1970)] have previously shown that Statistical Energy Analysis (SEA) is a robust tool for sound transmission loss problems in room acoustics. This paper presents recent developments in application of SEA to the structural-acoustic design of aircraft for control of interior noise. Developments for this application include the means to model boundary layer excitation of the fuselage; the means to model the dynamic response of both metallic-ribbed and composite sandwich pressurized shells; and the means to model the full noise and vibration reduction performance of multilayered interior trim and insulation treatments. The method has proven effective for acoustic design evaluation of new materials and constructions of aircraft structure or interiors but is equally attractive for optimization of the cost, weight, and packaging space of noise control treatments on aircraft of more conventional construction. Results of recent validation studies will be presented.
The analysis of a state-switched absorber design concept
Authors: Albanese Anne-Marie , Cunefare Kenneth
Published: October 2013

A tuned vibration absorber (TVA) is a spring-damper-mass system used in many industries for the suppression of a specific vibration frequency, and has application for the suppression of aircraft fuselage vibration. A state-switched absorber (SSA) is similar to a TVA, except that one or more components in the SSA is able to instantaneously and discretely change properties, thus increasing the effective bandwidth of vibration suppression. In order to design a replacement SSA for the classic TVA, the SSA must operate in the appropriate frequency range, be lightweight, and compact. An optimal SSA will also have a maximal frequency range between which it can switch. This paper discusses the development of a magnetorheological (MR) silicone gel used as the SSA switching element, the shape required to maintain a magnetic flux path, and the contribution of the magnet-mass to frequency shifting. The MR gel is iron-doped silicone, cured in the presence of a magnetic field. During operation, the applied magnetic flux is modified to change the natural frequency. The applied flux requirement forces the SSA to be a small ring. The SSA is designed to operate below 100 Hz.
Experimental evaluation of sound transmission through a thin-wall structure produced by turbulent pressure fluctuations
Authors: Efimtsov Boris M. , Baranov Sergey N.
Published: October 2013

Problems of physical modeling of sound transmission through a thin-wall structure produced by turbulent pressure fluctuations under excitation are presented. A method of evaluating the sound transmission loss of a thin-wall structure from turbulent pressure fluctuations on the basis of experimental data is proposed. The experiment is associated with full scale tests of structure in two adjacent reverberation chambers and with model tests in two adjacent model reverberation chambers and in the wind tunnel equipped with a similar model sound chamber. An example of such method realization is presented and this indicates a possibility of its practical realization in predicting the noise inside the passenger aircraft, produced by the turbulent boundary layer on its exterior surface. [Work supported by INTAS Grant No. 99-0088.]
Ultrafast optoacoustic wave generation effects on picosecond-timescale reflectivity measurements in metal thin films
Authors: Spicer James B. , Richardson Christopher J. K.
Published: October 2013

The increase in temperature at the surface of a metal during absorption of optical energy is a dynamic, multistep process. High-time-resolution, ultrafast measurements of thermal and elastic transients have proven to be useful for investigating the structure, thermophysical properties, and elastic properties of thin films [Paddock and Eesley, J. Appl. Phys. 60, 285–290 (1986)]. During ultrafast optical excitation of metals, the rapid deposition of energy causes the absorbing electrons to enter a superheated state, dispersing beyond the excitation volume before energy is deposited to the lattice with the rate of energy transfer between electrons and phonons being described using the electron–phonon coupling parameter. Typically, ultrafast reflectivity measurements taken immediately after excitation can be modeled using a completely thermal analysis if reduced values for the electron–phonon coupling parameter are used. These reduced values often vary substantially [Gusev and Wright, Phys. Rev. B 57, 2878–2888 (1998)] from accepted values that are experimentally determined from measurements using the cooling rate of superheated electrons. By including elastic contributions to the modeled signal at all times, agreement with measured signals can be obtained for short and long times using values for materials parameters that are in agreement with those obtained from other techniques.
Laser ultrasonic system for on-line steel tube gauging and process control
Authors: Levesque Daniel , Choquet Marc , Padioleau Christian , Neron Christian , Corbeil Christian , Talbot Richard , Bendada Abdelhakim , Monchalin Jean-Pierre , Kolarik Robert V. , Jeskey Gerald V. , Dominik Erich D. , Duly Larry J. , Samblanet Kenneth J. , Agger Steven E. , Roush Kenneth J. , Mester Michael L.
Published: October 2013

A laser ultrasonic system has been installed on a seamless tubing production line at The Timken Company and is being used to measure on-line the wall thickness of tubes during processing. The seamless process consists essentially in forcing a mandrel through a hot cylindrical billet in rotation and results in wall thickness variations that should be minimized and controlled to respect specifications. The system includes a Q-switched Nd-YAG laser for the generation of ultrasound by ablation, a long pulse very stable Nd-YAG laser for detection coupled to a confocal Fabry–Perot interferometer. The lasers, data acquisition, and processing units are housed in a cabin off-line and connected to a front coupling head located over the passing tube by optical fibers. The system also includes a fiber-coupled pyrometer to measure tube temperature profile and two fiber-coupled optical velocimeters to measure the coordinates at the probing location on the surface of the passing, rotating hot tube. During the presentation further details of the system will be disclosed, as well as typical results and examples of its diagnostic capability. [Work partially supported by Department of Energy under Award No. DE-FC07-99ID 13651.]
The verification system of the Comprehensive Nuclear-Test-Ban Treaty
Authors: Suarez Gerardo
Published: October 2013

The Comprehensive Nuclear-Test-Ban Treaty was opened for signature in September 1996. To date, the treaty has been signed by 165 countries and ratified by 93; among the latter, 31 out of the 44 whose ratification is needed for the treaty to enter into force. The treaty calls for the installation and operation of a verification system to ensure compliance. The verification system is composed of the International Monitoring System (IMS), the International Data Centre (IDC), and the On Site Inspection Division (OSI). The IMS is a global network of 321 stations hosted by 90 countries. The primary network is composed of 50 seismic stations, 31 of which are seismic arrays and 19 three-component, broad-band stations, 11 hydroacoustic stations, 60 infrasound arrays, and 80 radionuclide monitoring stations measuring radioactive particulates and noble gases in the atmosphere. The radionuclide network is supported by 16 laboratories. The auxiliary network of 120 seismic stations is interrogated on request by the IDC to improve the accuracy of the locations. The data from the 321 stations and from the laboratories is transmitted to the IDC in Vienna via a dedicated Global Communication Infrastructure (GCI) based on VSAT antennas. The IDC collects and processes the data collected from the four technologies and produces bulletins of events. The raw data and bulletins are distributed to state signatories. Upon entry into force, an on-site inspection may be carried out if it is suspected that a nuclear explosion has taken place. Since mid-1997, when the Provisional Technical Secretariat responsible for the implementation of the verification system began its work in Vienna, over 86% of the sites have been surveyed and the final location of the stations selected. By the end of 2002 this number will reach about 90%, essentially completing this phase. To date, 131 stations have been built or upgraded, and 80 are now sending data to the IDC; 112 others are under construction or under negotiation. Over 392 authorized users from 53 state signatories are now receiving data and products from the IDC. In addition, under the auspices of the signatories of the treaty, several projects are being funded to improve the calibration of seismic stations, the software used routinely at the NDC, and the analysis of radionuclides, among others.
Status report on the establishment of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) International Monitoring System (IMS) infrasound network
Authors: Vivas Veloso J. A. , Christie D. R. , Campus P. , Bell M. , Hoffmann T. L. , Langlois A. , Martysevich P. , Demirovik E. , Carvalho J. , Kramer A. , Molero Alonso A.
Published: October 2013

The infrasound component of the International Monitoring System (IMS) for Comprehensive Nuclear-Test-Ban Treaty verification aims for global detection and localization of low-frequency sound waves originating from atmospheric nuclear explosions. The infrasound network will consist of 60 array stations, distributed as evenly as possible over the globe to assure at least two-station detection capability for 1-kton explosions at any point on earth. This network will be larger and more sensitive than any other previously operated infrasound network. As of today, 85% of the site surveys for IMS infrasound stations have been completed, 25% of the stations have been installed, and 8% of the installations have been certified and are transmitting high-quality continuous data to the International Data Center in Vienna. By the end of 2002, 20% of the infrasound network is expected to be certified and operating in post-certification mode. This presentation will discuss the current status and progress made in the site survey, installation, and certification programs for IMS infrasound stations. A review will be presented of the challenges and difficulties encountered in these programs, together with practical solutions to these problems.
Post-installation activities in the Comprehensive Nuclear Test Ban Treaty (CTBT) International Monitoring System (IMS) infrasound network
Authors: Vivas Veloso J. A. , Christie D. R. , Hoffmann T. L. , Campus P. , Bell M. , Langlois A. , Martysevich P. , Demirovik E. , Carvalho J. , Kramer A. , Molero Alonso A. , Wu Sean F.
Published: October 2013

The provisional operation and maintenance of IMS infrasound stations after installation and subsequent certification has the objective to prepare the infrasound network for entry into force of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). The goal is to maintain and fine tune the technical capabilities of the network, to repair faulty equipment, and to ensure that stations continue to meet the minimum specifications through evaluation of data quality and station recalibration. Due to the globally dispersed nature of the network, this program constitutes a significant undertaking that requires careful consideration of possible logistic approaches and their financial implications. Currently, 11 of the 60 IMS infrasound stations are transmitting data in the post-installation Testing & Evaluation mode. Another 5 stations are under provisional operation and are maintained in post-certification mode. It is expected that 20% of the infrasound network will be certified by the end of 2002. This presentation will focus on the different phases of post-installation activities of the IMS infrasound program and the logistical challenges to be tackled to ensure a cost-efficient management of the network. Specific topics will include Testing & Evaluation and Certification of Infrasound Stations, as well as Configuration Management and Network Sustainment.
Patch nearfield acoustical holography
Authors: Williams Earl G.
Published: October 2013

Nearfield acoustical holography (NAH) requires the measurement of the pressure field over a complete surface in order to recover the normal velocity on a nearby vibrating concentric surface. Patch NAH provides a major advancement by eliminating the need for complete surface pressure scans—only a small area needs to be scanned to determine the normal velocity on the corresponding (small area) concentric patch on the vibrator. The theory of patch NAH is based on: (1) an analytic continuation of the patch pressure which provides a spatially tapered aperture extension of the field; and (2) a decomposition of the transfer function (pressure to velocity and/or pressure to pressure) between the two surfaces using the singular value decomposition for general shapes and the fast Fourier transform for planar surfaces. Inversion of the transfer function is stabilized using Tikhonov regularization and the Morozov discrepancy principle. Experimental results show that the normal velocity reconstruction errors (rms) for a point-driven vibrator over 200–2700 Hz average less than 20% for two surfaces 0.4 cm apart. Reconstruction of the active normal acoustic intensity was also achieved, with less than 30% rms error over the frequency band. [Work supported by ONR.]
On the validity and convergence of the Helmholtz equation least squares solutions
Authors: Semenova Tatiana , Wu Sean F.
Published: October 2013

The problem of reconstruction of acoustic radiation from arbitrary shaped vibrating bodies is often encountered in engineering applications. The Helmholtz equation least-squares (HELS) method proposed by Wu (2000) is an assumed-form solution method in which the reconstructed acoustic pressure is found as a superposition of spherical waves. The unknown coefficients are determined by matching the assumed-form solution to the measured acoustic pressures at a number of points around the source and their errors are minimized by the least-squares method. To further minimize the errors of reconstruction, constraints are used on the surface of the object. In this paper a two-dimensional, noncircular object is considered and the two-dimensional Helmholtz equation is solved. The locations of singularities in the analytic continuation of the solution across the source surface are found using the Schwarz function of the source surface. It will be shown that the HELS solution remains bounded and close to the true pressures inside the minimum circle enclosing the object as well as outside. Other types of modifications of the HELS method for reconstruction of acoustic radiation in an exterior two-dimensional region will be considered. [Work supported by NSF.]
Ecological prognosis near intensive acoustic sources
Authors: Kostarev Stanislav A. , Makhortykh Sergey A. , Rybak Samuil A.
Published: October 2013

The problem of a wave-field excitation in a ground from a quasiperiodic source, placed on the ground surface or on some depth in soil is investigated. The ecological situation in this case in many respects is determined by quality of the raised vibrations and noise forecast. In the present work the distributed source is modeled by the set of statistically linked compact sources on the surface or in the ground. Changes of parameters of the media along an axis and horizontal heterogeneity of environment are taken into account. Both analytical and numerical approaches are developed. The latter are included in the software package VibraCalc, allowing to calculate distribution of the elastic waves field in a ground from quasilinear sources. Accurate evaluation of vibration levels in buildings from high-intensity underground sources is fulfilled by modeling of the wave propagation in dissipative inhomogeneous elastic media. The model takes into account both bulk (longitudinal and shear) and surface Rayleigh waves. For the verification of the used approach a series of measurements was carried out near the experimental part of monorail road designed in Moscow. Both calculation and measurement results are presented in the paper.
Consonant contrasts in a multiple, simultaneous word identification task
Authors: Ericson Mark , Mishler Pamela
Published: October 2013

People often have difficulty communicating in the presence of concurrent conversations. This well-known ‘‘cocktail party effect’’ can be described as a combination of energetic and informational masking. The purpose of this study was to measure and model the effects of energetic and informational masking that occur when two people speak at the same time. The word identification test used in the experiments was the Modified Rhyme Test (MRT), which afforded a multitude of initial and final consonant pairs when phrases were played simultaneously. The MRT was used as both the stimulus and the masker, which were presented monaurally at 75 dB SPL over Sennheiser HD-520 headphones to four normal hearing listeners. The independent variables included 30 pairs of MRT word lists, and twelve pairs of same-sex talkers. The dependent variable was speech (consonant) intelligibility as measured with the MRT. Results will be discussed in the context of place of articulation, manner of articulation, signal-to-noise-ratio of the phoneme pairs, and informational masking model predictions.
Realistic listening improved by adding fine structure
Authors: Stickney Ginger S. , Nie Kaibao , Zeng Fan-Gang
Published: October 2013

Speech communication often takes place in noisy and reverberant environments. Unfortunately, cochlear implant (CI) users perform significantly poorer than normal hearing listeners under adverse conditions. We hypothesize that the noise susceptibility of CI users is largely due to the lack of encoding the fine structure cue. Most CI speech processing algorithms extract and encode the slowly varying amplitude modulation in speech (the envelope), while the rapidly varying fine structure is replaced with a fixed rate carrier. We have developed a new speech processing algorithm, called Frequency-Amplitude-Modulation-Encoding (FAME), which codes both amplitude and frequency modulations. Normal hearing listeners were presented with IEEE sentences in the presence of an interfering voice as a function of the number of noise bands (information channels) and signal-to-noise level. Sentence recognition with a competing talker was generally improved with the addition of fine structure, and by as much as 60% with 4 frequency bands (i.e., from 20%–80% at a 20 dB signal-to-noise level). This result suggests that the fine structure is important for speech recognition under realistic situations and should be encoded in future cochlear implants.
Fricative spectral moments and the perception of anticipatory coarticulation
Authors: Katz William F. , Bharadwaj Sneha V. , Stettler Monica P. , Assmann Peter F.
Published: October 2013

Spectral moments (mean, variance, skewness, kurtosis) have been used to classify fricative place of articulation in English and other languages. For example, studies have shown the first spectral moment (centroid) is consistently lower in /∫/ than in /s/. It has also been hypothesized that fricative spectral moments contribute to listeners’ judgments of vowel identity in fricative-vowel (FV) syllables, providing acoustic cues for the perception of anticipatory coarticulation. To study the relationship between fricative spectral moments and traditional fricative spectral attributes as cues to the perception of coarticulation, we obtained a database of FV syllables (/si/, /su/, /∫i/, /∫u/) produced by adults and children (ages 5 and 7). Acoustic analyses examined spectral and temporal properties of the signal, while a perceptual experiment determined how adult listeners use gated ‘‘slices’’ (1/2 fricative, 3/4 fricative, full fricative, fricative plus 1/2 vowel) to identify the fricative and upcoming vowel in the FV syllables. The identification of full syllables showed effects of gate length and talker group, while the vowel identification data revealed little difference as a function of either variable. Logistic regression is used to test the independence of fricative and vowel cues in syllable perception, and to model developmental trends.
The effects of completely-in-the-canal hearing aids, active noise reduction headsets, and ambient noise on speech intelligibility
Authors: Hall John , Ericson Mark , Mishler Pamela
Published: October 2013

Many people with hearing loss need to communicate and work in high noise environments. Hearing aids and headsets are often worn to protect the ear from further damage and facilitate communication. The purpose of this study was to determine the effects of the active noise reduction (ANR) headsets and Completely-in-the-Canal (CIC) hearing aids on speech intelligibility in ambient noise. Six male listeners with noise-induced hearing loss were each fitted with two digital CIC hearing aids. The listeners wore the hearing aids successfully for one year. The speech stimuli were presented over the ANR headphones in quiet and in 95 dB and 105 dB SPL of ambient pink noise. The independent variables were the active noise reduction, hearing aids, and noise level. All MRT stimuli were presented at the most comfortable loudness level. The dependent variable was speech intelligibility as measured with the Modified Rhyme Test (MRT). A main effect was discovered for noise, however no effect was found for active noise reduction or hearing aids. Although no overall effect was found with ANR or hearing aids on speech intelligibility there were differences across phoneme identifications and initial and final consonants.
An evaluation of the semantic categorization task in Japanese word recognition
Authors: Yoneyama Kiyoko
Published: October 2013

In this paper an evaluation of the semantic categorization task in Japanese word recognition is reported. Data used in this experiment were taken from Yoneyama (2002) in which fillers were the words for gyesh responses for semantic categories. In this experiment, participants had to deal with 28 multiple semantic categories. Two findings were concluded. First, although participants generally showed a good performance, the degree of task difficulty among 28 semantic categories was not equal. The average percent correct for gyesh filler-word responses by participants was 95%. The mean values of the words responded to correctly within each category and the number of words correctly classified by at least 93% of the listeners both indicate such tendencies. Second, although the degree of task difficulty among semantic categories within the experiment varied, the selection of semantic categories by itself seemed to be reasonable. The lowest number of words correctly classified by at least 93% of the participants was 17 out of 25 filler words for 4 categories, suggesting that at least 17 of the filler words were considered by general undergraduate students to be good instances of these semantic categories. A generalized methodology to select words in semantic categories will be also discussed. [Work supported by NIH (PI: Keith Johnson).]
Identification of English /r/ and /l/ in white noise by native and non-native listeners
Authors: Ueda Kazuo , Yamasaki Noriko , Komaki Ryo
Published: October 2013

Fifty-three English word pairs, minimally contrasting in /r/–/l/, were identified by 14 native American English (AE) listeners and 42 native Japanese (J) listeners, under systematically varied signal-to-noise ratios (SNR) which ranged from no-noise to 21 dB. Word identification for filler contrasts (FL: /d/–/k/, /m/–/n/, etc.) was also tested under the same SNR conditions. Results show that: (a) identification accuracy by the AE listeners was nearly 100% in the no-noise condition compared to about 70% with a SNR of 21 dB; (b) the J listeners showed similar identification accuracy to the AE listeners for the FL words, whereas they performed much poorer on the /r/–/l/ contrasted words (70% accuracy without noise and 55% accuracy with a SNR of 21 dB); and (c) /r/–/l/ identification accuracy was affected by an interaction between the consonant position in a word and the listeners’ native languages. The role of perceptual assimilation in the interaction will be discussed. [Work supported by TAO and JSPS, Japan.]
Influence which the sound as a noise has on maintenance of phoneme information
Authors: Yagyu Takashi
Published: October 2013

This research is investigated from the viewpoint of cross-language processing about the influence which the noise generated by reading aloud has to the maintenance results of phoneme information. If a sentence is read aloud simultaneously when holding phoneme information, the quantity of the phoneme information which can be held and set will decrease. This phenomenon can check the rehearsal of the phoneme information which the noise produced by reading a sentence aloud holds, and it is also possible that maintenance results fall as a result. Then, in this research, the cognitive psychological experiment was conducted using the dual-task method of reading aloud of a sentence, and memory of a word (phoneme information). Two conditions of a native language and a foreign language were set up as a noise generated by reading aloud, and it examined to what noise memory of phoneme information would decline from the point of the individual difference of phonological short-term memory (phonological STM) capacity. Consequently, the more phonological STM capacity was large, the more it was suggested that the stoutness of the phoneme memory to a similar noise increases.
Multiple talker effects in auditory–visual speech perception among older adults
Authors: Cienkowski Kathleen
Published: October 2013

Talker variability effects have been shown for speech stimuli presented auditorily to young adult and older adult participants. Recent investigations suggest that similar variability is seen among young adults for auditory–visual congruent and discrepant stimuli. Older adults are reported to be at a disadvantage for processing information spoken by multiple talkers. Some investigators have suggested that perceptually demanding conditions, such as listening in noise may be more difficult for older listeners. In the current investigation, talker variability effects for CV syllables were examined in multiple modalities visual-only, auditory-only, and auditory–visual for older listeners. Auditory–visual presentations were of two types: congruent [auditory and visual were of the same token —/visual bi and auditory bi/] or disparate [/visual gi and auditory bi/]. The disparate condition has elicited the McGurk effect, in which listeners may report a fused response that is neither the auditory or the visual component of the stimulus. The talkers were 11 individuals with known equivalent auditory intelligibility. Consistent with previous work, individual older listeners varied considerably in their overall perceptions, from complete fusion for all talkers to almost no fusion for any talker. Further, older listeners demonstrated poorer performance in comparison to younger adults in the multitalker condition.
Nasal consonant speech errors: Implications for ‘‘similarity’’ and nasal harmony at a distance
Authors: Walker Rachel , Hacopian Narineh , Taki Mariko
Published: October 2013

It has been observed that nasals interact with ‘‘similar’’ consonants in phonological long distance nasal harmony [Walker, BLS 26, 321–332 (2000)]. In such patterns, nasals cause other consonants in a word to become nasal. Voiced stops and liquids are preferentially affected; in some cases obligatorily homorganic with the nasal. In this study we ask whether a parallel occurs in consonants with greater likelihood to participate in speech errors with nasals; specifically, is preferred interaction of voiced and homorganic stops with nasals also evident in the error pattern of a language without nasal harmony? Experiments were conducted on English speakers using the SLIPS technique [Baars and Motley, Catalog of Selected Documents in Psychology, 1974]. CVC word pairs were presented for reading. Critical pairs, primed to encourage initial consonant errors, were cued to be spoken. Experiment 1 (35 subjects) investigated whether more errors involve nasals and voiced stops than nasals and voiceless stops (partially replicates Stemberger’s 1991 study). Experiment 2 (37 subjects) examined whether more errors involve nasals and homorganic voiced stops than nasals and heterorganic voiced stops. Results indicate that consonants participating in more errors with nasals parallel those preferentially affected in long distance nasal harmony. [Work supported by a Zumberge grant.]
Accessing coarticulatory information
Authors: Curtin Suzanne , Ladhar Neelam , Werker Janet
Published: October 2013

The speech signal is comprised of coarticulatory cues. Here, we explore whether adults’ access to coarticulatory information depends upon the particular language task. Specifically, we tested adults’ sensitivity to coarticulation when segmenting new sequences versus remembering presegmented items. Forty undergraduates were familiarized to either a continuous string of appropriately coarticulated nonsense CV syllables where every third syllable was stressed to facilitate segmentation, or to the same CV syllables presegmented into trisyllabic units without any stress contour. During the test phase, adults were presented with familiar and novel sequences appropriately coarticulated, and to both sequence types with inappropriate coarticulation. Subjects rated the familiarity of items using a seven point scale. Both groups rated familiar test sequences as more familiar than novel sequences. However, only the group presented with presegmented items demonstrated sensitivity to coarticulation. These subjects, compared to the segmentation group, significantly preferred the coarticulated items (p<0.05). These results suggest that access to information depends on the task. In the case of word segmentation, adults play attenation to the most useful properties (in this case, stress). Whereas adults in the presegmented group were able to pick up all the details of the sequences since their task only required word recognition.
The perception of gated Dutch diphones
Authors: McQueen James M. , Smits Roel , Cutler Anne , Warner Natasha
Published: October 2013

The results of a large-scale speech perception study are reported. Eighteen Dutch listeners identified gated fragments of 1179 Dutch diphones. Diphones were presented six times (for some diphones beginning with voiceless stops, four times) to each listener, in fragments ranging from the shortest gate (the first sixth of the diphone), through to the longest gate (the complete diphone). Order of presentation of all gates of all diphones was fully randomized. Listeners were asked to identify the complete diphone on every trial. The results showed that listeners based their decisions on the acoustic information available in the stimuli, not on higher-order factors such as phoneme occurrence frequencies or transitional probabilities. Perceptual confusions reflected the temporal evolution of phoneme similarities (for example, in their shorter gates, long vowels were confused with their short counterparts). This database provides detailed information about the perceptual hypotheses which listeners entertain about phoneme sequences, as those sequences unfold over time. It can also be used to generate predictions about the temporal pattern of activation of spoken words. Such data are necessary for the evaluation and further development of current models of spoken word perception, in which fine-grained acoustic information is mapped continuously onto the mental lexicon.
Learning-induced neural plasticity associated with acquisition of a difficult second-language phonetic contrast
Authors: Callan Daniel , Kubo Rieko , Callan Akiko , Masaki Shinobu
Published: October 2013

Adult native Japanese speakers have difficulty perceiving the English /rl/ phonetic contrast even after years of exposure. However, after extensive perceptual identification training long lasting improvement in identification performance that generalizes to novel stimuli can be attained. In this fMRI study we investigate localized changes in brain activity associated with one-month of extensive feedback-based perceptual identification training by native Japanese speakers learning the English /rl/ phonetic contrast. Before and after training separate functional brain imaging sessions were conducted for identification of the English /rl/ contrast (difficult for Japanese speakers), /bg/ contrast (easy), and /bv/ contrast (difficult). Neural plasticity, denoted by exclusive enhancement in brain activity for the /rl/ contrast (not present for the /bv/ and /bg/ conditions), does not only occur in brain regions involved with acoustic–phonetic processing (superior temporal areas, supramarginal gyrus, planum temporale) but also in additional bilateral cortical (Broca’s area, premotor cortex, orosensory cortex) and subcortical regions (cerebellum, basal ganglia, substantia nigra) involved with speech production as well as with formation of perceptual–motor mappings. The results support the hypothesis that learning of an auditory–articulatory mapping improves identification performance by allowing a perception to be made in reference to potential action. [Work supported by TAO, Japan.]
Long range sediment tomography
Authors: Miller James H.
Published: October 2013

The development of long range sediment tomography using shot data and its application in various field experiments is presented. Whereas traditional ocean acoustic tomography has mainly relied on linear inverse theory using the travel time of rays in deep water, our technique relies on nonlinear optimization techniques using the frequency-dependent travel time of normal modes in shallow water. Our experience with broadband sediment tomography using explosive sources started with the Barents Sea Polar Front Experiment where sediment properties were extracted using ground wave analysis. The techniques were further refined during the Shelf Break Primer Experiment in the New England Bight where a nonlinear inversion scheme using the Genetic Algorithm was successfully applied. The inversion scheme was based on modal travel time dispersion characteristics, which in shallow water conditions, is highly sensitive to the bottom properties. Advanced signal processing tools for the space–time–frequency processing and hybrid optimizaton techniques for global search were developed and implemented in parallel. In addition to the individual modal arrival times, emphasis has now been placed on the arrival corresponding to the Airy phase. These inversion techniques are currently being applied to the data from ASIAEX-East China Sea Experiment. Characteristics of this tomography approach such as spatial coverage, resolution, error bars, robustness, and simple instrumentation requirements will be presented. The usefulness of this inversion approach as a rapid environmental assessment tool will be highlighted. [Work supported by ONR.]
Analysis of sound propagation data taken in the East China Sea
Authors: Peng Zhaohui , Zhou Ji-xun , Zhang Renhe , Dahl Peter H.
Published: October 2013

As a part of the Asian Seas International Acoustic Experiment (ASIAEX2001), sound propagation data from wideband (explosive) sources were recorded in the East China Sea by using a 32-element suspended array. The propagation was measured as a function of range in two perpendicular tracks (one up to 60 km) and as a function of azimuth for a fixed range of 30 km. Supporting environmental data, obtained from a 17-element thermister chain, XBT, and CTD, showed very complex variation in the water column. In this paper, transmission loss (TL) as a function of range, frequency and azimuth is briefly introduced. Seabottom acoustic parameters such as density, velocity, and attenuation are inverted from the sound propagation data. Then, these parameters plus internal wave data are used as inputs to PE and normal-mode codes qualitatively to explain observed strong fluctuations in sound propagation. The inversion techniques used for estimating seabottom parameters, including spatial mode filtering and dispersion analysis, are also discussed. [Work supported by the National Natural Science Foundation of China and ONR.]
Time- and space-varying interference patterns of broadband acoustic field sampled by drifting buoys during E
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E 97 experiments
Authors: Hermand Jean-Pierre , Scevenels Serge , Absil Frans G. J.
Published: October 2013

During the winter of 1997 SACLANTCEN deployed a fixed controlled sound source, a vertical receive array, and drifting hydrophone buoys in a complex coastal environment on the western Sicilian shelf (ENVERSE 97). The acoustic impulse response of the medium was measured in a broad frequency band as a function of range and azimuth from the source, using repeated, large time-bandwidth-product FM transmissions and DGPS positioning. This paper investigates the combined effects of water column and bottom variability upon the space-frequency distribution of the sound-field intensity. The time and space dependence of extracted features such as patterns of field extrema are analyzed and related to the observed environmental conditions. In particular, perturbations of acoustic field invariants are detected and shown to be well correlated with the range-dependent bottom properties and the time-varying ocean sound speed and current fields. Preliminary modeling (C-SNAP) results obtained from concurrent oceanographic and geophysical ground-truth data (enverse 98) are compared to the acoustic measurements to determine their sensitivity to various environmental parameters. [Work supported by the Royal Netherlands Navy.]
Temporal resolutions of time-reversal and passive-phase conjugation for underwater acoustic communications. I. Stationary source and receivers in a dynamic shallow-water environment
Authors: Yang T. C.
Published: October 2013

Multipath arrivals cause interference between transmitted symbols and hence, symbol errors in underwater acoustic communications. A time-reversal mirror uses the ocean to combine the multipath arrivals and can be used for underwater acoustic communications. Passive-phase conjugation uses the received data of a probe signal to deconvolve the channel transfer function and thereby removes the multipath effects. In this paper, we study the following temporal resolutions of a time-reversal or passive-phase conjugation process as applied to underwater acoustic communications: (1) the time resolution or the pulse width of a backpropagated, time-compressed pulse as compared with the original transmitted pulse; (2) the effectiveness of temporal focusing as measured by the peak-to-sidelobe ratio of the backpropagated or phase-conjugated pulse; both pulse elongation and sidelobe leakages are causes of intersymbol interference and bit errors for communications; (3) the duration of temporal focusing or the temporal coherence time of the underwater acoustic channel; and (4) the stability of temporal focusing as measured by the phase fluctuations of successive pulses (symbols). BPSK signals collected at sea were used to extract the above four parameters. The bit error rates are modeled with simulated data. [Work supported by ONR.]
Temporal resolutions of time-reversal and passive-phase conjugation for underwater acoustic communications. II. The effect of source motion
Authors: Yang T. C.
Published: October 2013

Multipath arrivals cause interference between transmitted symbols and hence, symbol errors in underwater acoustic communications. A time-reversal mirror uses the ocean to combine the multipath arrivals and can be used for underwater acoustic communications. Passive-phase conjugation uses the received data of a probe signal to deconvolve the channel transfer function and thereby removes the multipath effects. In this paper, we study the following temporal resolutions of a time-reversal or passive-phase conjugation process as applied to underwater acoustic communications: (1) the time resolution or the pulse width of a backpropagated, time-compressed pulse as compared with the original transmitted pulse; (2) the effectiveness of temporal focusing as measured by the peak-to-sidelobe ratio of the backpropagated or phase conjugated pulse; both pulse elongation and sidelobe leakages are causes of intersymbol interference and bit errors for communications; (3) the duration of temporal focusing or the temporal coherence time of the underwater acoustic channel; and (4) the stability of temporal focusing as measured by the phase fluctuations of successive pulses (symbols). We analyze BPSK signals collected at sea from a moving source, extract the above four parameters, and evaluate the bit error rate. [Work supported by ONR.]
The Asian free-reed mouth organs
Authors: Cottingham James P.
Published: October 2013

Mouth-blown instruments employing a free reed coupled to a pipe resonator have long been known and used throughout East and Southeast Asia. Details of the origin and development of these instruments are not known, but are closely connected with the history and prehistory of a multitude of ethnic groups. These instruments exemplify a pipe–resonator coupling significantly different from the standard wind instruments of European origin. The free reed used is approximately symmetric, often operating on both directions of air flow. In some cases the reed is at or near one end of a closed pipe, but in other examples the reed is mounted in the side of a resonator open at both ends. The instruments can be either multiple pipe instruments with one pipe per note, or a pipe with a single reed and tone holes. A number of experimental studies have been conducted on examples of Asian free-reed instruments, primarily the khaen, bawu, and sheng. These include studies of reed vibration, measurements of sound spectra, and impedance measurements of the pipes. Comparisons have been made between experimental results and theoretical work on the coupling of reed vibration with the pipe resonator.
Construction practices in pre-Hispanic flutes
Authors: Rawcliffe Susan
Published: October 2013

The ancient cultures of the Americas were separated by thousands of miles and thousand of years. There was a long history of trade over the miles and the years with many shared cultural ideals and artifacts, as evidenced by their musical instruments. Flutes were the most prevalent instruments found throughout the ancient Americas. Some types are unique to the pre-Hispanic world. Although flutes were constructed from a variety of materials, including bone, cane, seed pods, skulls, it is primarily the ceramic ones that survived, and it is ceramic flutes which form the bulk of this writer’s work and research. This paper includes musical demonstrations to show how ancient flutemakers could have manipulated timbre during construction. Clay’s plasticity enabled the construction of some instruments, and limited the development of others. Pitch jump flutes, certain Veracruzano whistles, and chamberduct flutes and whistles all share the addition of clay flaps or chambers around the aperture, as do hooded pipes. Some instruments exhibit a seemingly cultural predilection for complex tones that are windy, raspy, or animalistic. Simple adjustments of the airduct promote these timbres. Also included will be samples of the original sounds of ancient flutes.
Ancient noise generators
Authors: Beristain Sergio , Menchaca Rolando , Velazquez Roberto
Published: October 2013

There has been found a whole family of similar artifacts which produce singing noises. These noises sometimes resemble those sounds generated by some animals and/or naturally produced by strong winds passing through holes and edges. It means that these sounds have wide frequency spectrums and very often some clear tones are identified. The original purpose of these artifacts is unknown, but some researchers think that some were used in mortuary ceremonies and employed by H-men. The Olmecan whistle previously presented belongs to this family, and now it is compared with a bone or wooden instrument shown in the Florentine codex.
The musical instruments in the codexes mixtecos
Authors: Gomez Luis A.
Published: October 2013

The objective of this work is to describe the inventory of prehispanic musical instruments in the Codexes Mixtec: Vindobonensis, Nuttall, Selden, Colombino, Becker I and II. For this, relative data are gathered as to their quantity, localization and classification; their function in the Meso-American colored writing; and the meaning of the image of which they are part. This inventory will allow academics of different disciplines to select and to locate the image of the musical instrument of interest quickly and to understand in a general way, its function in the image that contains it. (To be presented in Spanish.)
History of animal bioacoustics
Authors: Popper Arthur N. , Dooling Robert J.
Published: October 2013

The earliest studies on animal bioacoustics dealt largely with descriptions of sounds. Only later did they address issues of detection, discrimination, and categorization of complex communication sounds. This literature grew substantially over the last century. Using the Journal of the Acoustical Society of America as an example, the number of papers that fall broadly within the realm of animal sound production, communication, and hearing rose from two in the partial first decade of the journal in the 1930’s, to 20 in the 1970’s, to 92 in the first 2 years of this millennium. During this time there has been a great increase in the diversity of species studied, the sophistication of the methods used, and the complexity of the questions addressed. As an example, the first papers in JASA focused on a guinea pig and a bird. In contrast, since the year 2000 studies are often highly comparative and include fish, birds, dolphins, dogs, ants, crickets, and snapping shrimp. This paper on the history of animal bioacoustics will consider trends in work over the decades and discuss the formative work of a number of investigators who have spurred the field by making critical theoretical and experimental observations.
A quantitative comparison of theory and experiments on high intensity focused ultrasound (HIFU) induced heating in a vascularized tissue phantom
Authors: Roy Ronald A. , Huang Jinlan , Holt R. Glynn
Published: October 2013

High intensity focused ultrasound (HIFU) can be used to help control bleeding, both from individual blood vessels as well as from gross damage within the capillary bed. The dominant mechanism is rapid localized heating, and vascularity limits ones ability to elevate the temperature of blood vessels owing to convective heat transport. To better understand HIFU-induced heating in tissues with vascular structure, we employ a numerical scheme that couples models for ultrasound propagation, acoustic streaming, ultrasound heating, and blood cooling in Newtonian viscous media. We coordinate the theoretical effort with a series of in vitro experiments employing nonuniform flow-through tissue phantoms and designed to provide a ground truth verification of the model predictions. Calculated and measured results are compared over a range of parameter values (insonation pressure, insonation time, and flow rate). We demonstrate excellent agreement between predictions and measurements, and the simulations are extended to a study of the efficacy of HIFU in producing temperature elevations in large and small blood vessels. [Work supported by DARPA and the U.S. Army.]