bluuebunny/crossref_metadata_2025 huggingface dataset:
Bubbles trapped on the surface of kidney stones as a cause of the twinkling artifact in ultrasound imaging
Authors: Sapozhnikov Oleg , Lu Wei , Bailey Michael , Kaczkowski Peter , Crum Lawrence
Published: May 2013

A twinkling artifact (TA) associated with urinary calculi has been described as rapidly changing colors on Doppler ultrasound. The purpose of this study was to investigate the mechanism of TA. Doppler processing was performed on raw per channel radio-frequency data collected when imaging human kidney stones in degassed water. Suppression of twinkling by an ensemble of computer generated replicas of a single received signal demonstrated that the TA arises from variability among the acoustic signals and not from electronic signal processing. This variability was found to be random in nature, and its suppression by elevated static pressure, and its return when the pressure was released, suggests that the presence of surface bubbles on the stone is the mechanism that gives rise to the TA. Submicron size bubbles are often trapped in crevices on solid objects, but the presence of these bubbles in vivo is unexpected. To further check this mechanism under conditions identical to in vivo, stone-producing porcine kidneys were harvested en bloc with a ligated ureter and then placed into a pressure chamber and imaged at elevated atmospheric pressure. The result was similar to in vitro. [Work supported by NIH DK43881, DK092197, RFBR, and NSBRI through NASA NCC 9-58.]
The use of twinkling artifact of Doppler imaging to monitor cavitation in tissue during high intensity focused ultrasound therapy
Authors: Khokhlova Tatiana D. , Li Tong , Sapozhnikov Oleg A. , Hwang Joo Ha
Published: May 2013

In high intensity focused ultrasound (HIFU) therapy, it is important to monitor the presence and activity of microbubbles in tissue during treatment. The current methods—passive cavitation detection (PCD) and B-mode imaging—have limited sensitivity, especially to small-size, non-violently collapsing microbubbles. Here, a new method for microbubble detection is proposed, based on “twinkling” artifact (TA) of Doppler imaging. TA occurs when color Doppler ultrasound is used to image hard objects in tissue (e.g., kidney stones) and is displayed as brightly colored spots. As demonstrated recently, TA can be explained by irregular scattering of the Doppler ensemble pulses from the fluctuating microbubbles trapped in crevices of the kidney stone. In this work, TA was used to detect cavitation in tissue and in polyacrylamide gel phantoms during pulsed 1 MHz HIFU exposures with different peak negative pressures (1.5–11 MPa). At each pressure level, the probability of cavitation occurrence was characterized using TA and the broadband signals recorded by PCD, aligned confocally with the HIFU transducer. The results indicate that TA is more sensitive to the onset of cavitation than conventional PCD detection, and allows for accurate spatial localization of the bubbles. [Work supported by RFBR and NIH (EB007643, 1K01EB015745, and R01CA154451).]
Leveraging microelectromechanical microphones inherent matching to reduce noise using multiple microphone elements
Authors: Conklin Wade
Published: May 2013

Signal-to-noise ratio (SNR) is a critical parameter in the adoption of small scale (~1 mm) microphones for use in hearing aids. As a result, electret microphones have dominated the market since their invention in the 1960’s. Significant effort is being invested to increase the SNR of microelectromechanical (MEMs) microphones near that of electrets. This work covers the approach of using multiple microphone elements to increase SNR. It explores the theory, examines the dependence of the SNR improvement on the matching of the microphone elements, and compares measurements on a single element microphone versus a multiple element microphone. Finally, it examines why the MEMs fabrication process lends itself to this usage and compares the trade-offs in scaling elements versus scaling size.
Acoustic interference and diffraction experiments in the advanced laboratory class
Authors: Morrison Andrew
Published: May 2013

Many acoustic analogs to classical optics experiments can be performed with low-cost ultrasonic transducers. Mounts for the ultrasonic transducers have been designed to be produced with desktop 3D printing technology. The designs are open and available for use and modification. Examples of experiments that can be done with this system include single-slit diffraction, double-slit interference, and Lloyd’s mirror experiments. Although simple in appearance, these experiments provide a rich opportunity for students to explore acoustic phenomena in the advanced laboratory such as the radiation pattern of the transducer and rudimentary acoustic beamforming techniques. The lab activities for use in intermediate or advanced acoustics lab classes are included in a revised laboratory manual currently in development. The lab manual has experiments appropriate for both introductory and advanced acoustics labs covering a range of acoustics subfields.
Creating interactive acoustics animations using Mathematica's Computable Document Format
Authors: Russell Daniel A.
Published: May 2013

The computational and graphical prowess of Mathematica has long made it a powerful educational tool for creating effective animations of acoustic and vibration phenomena [Russell, J. Acoust. Soc. Am. 106, 2197 (1999) and Sparrow and Russell, J. Acoust. Soc. Am. 103, 2987 (1998)]. Once an animation has been created within Mathematica it is relatively easy to convert the animation to an animated GIF file for display on a website [Russell, J. Acoust. Soc. Am. 114, 2308 (2003)]. However, such animations, while effective at conveying or illustrating complicated acoustic phenomena, are “static” in the sense that they are not interactive and a person viewing the animation cannot change parameters. Recently, Wolfram Research implemented a new Computable Document Format that allows interactive plots and animations to be inserted into webpages and electronic documents. A free CDF player from Wolfram allows viewers to interact with plots and animations by moving sliders to change values of parameters. This talk will demonstrate the process of creating a CDF animation for embedding in a webpage. Other, more complex, demonstrations will also be showcased do illustrate the potential capabilities of CDF as an educational tool.
Experimental and numerical characterization of aerodynamic noise applied to moderate Reynolds number airflow
Authors: Fujiso Yo , Van Hirtum Annemie , Nozaki Kazunori , Wada Shigeo
Published: May 2013

In the study of aerodynamic noise, a tackling challenge is to understand the underlying aeroacoustic mechanisms leading to its generation. The current paper aims at contributing to the noise characterization by focusing on moderate Reynolds number (100 ≤ Re ≤ 10000) airflow circulating through a rectangular channel containing a trapezoidal obstacle near the outlet. The outcome of large Eddy simulation and acoustic experiments are compared for different experimental boundary conditions at inlet and outlet, and for different apertures below the obstacle.
Improving the acoustic performance of low noise road surfaces using resonators
Authors: Männel Manuel , Forssén Jens , van der Aa Bart
Published: May 2013

Road surfaces made of porous asphalt are widely used to reduce the tire-road-noise generated during the rolling process of passenger cars and trucks. As the engine noise was reduced significantly in the last decades the tire-road-noise is the main sound source for driving speeds of 40 km/h (25 mile/h) and higher for passenger cars. This means that low noise road surfaces may not only be used on highways but also on inner-city main roads to generate a significant reduction on traffic noise. However, the acoustic performance of road surfaces made of porous asphalt is limited as a result of the trade-off between acoustic properties and road surface durability. By including resonators, e.g., of Helmholtz type in the porous road surface, it is possible to improve its absorbing performance without loss in durability. The paper describes recent research activities on such resonators in porous road surfaces made in the European project HOSANNA. The acoustic properties in terms of insertion loss have been calculated for different arrays of resonators. Measurements on realized porous road surfaces including resonators were carried out. The results show that resonators can improve the acoustic performance of porous road surfaces substantially.
Guidance for new policy developments on railway vibration
Authors: Peris Eulalia , Woodcock James , Sica Gennaro , Sharp Calum , Moorhouse Andy , Waddington David
Published: May 2013

Vibration is one of the main problems associated with railways in residential areas. To ensure quality of life and well being of inhabitants living in the vicinity of route paths, it is important to evaluate, understand, control, and regulate railway noise and vibration. Much attention has been focused on the impact of noise from railway but the consideration of railway-induced vibration has often been neglected. This paper aims to provide policy guidance based on results obtained from the analyses of relationships estimated from ordinal logit models between human response and vibration exposure. This was achieved using data from case studies comprised of face-to-face interviews and internal vibration measurements (N = 755) collected within the study “Human Response to Vibration in Residential Environments” by the University of Salford. First, the implications of neglecting vibration in railway noise policies are presented. Second, the influence of different times of day when residents are exposed to railway vibration are presented and compared to current standards. Finally, the main factors that were found to influence railway vibration annoyance are presented and expressed as weightings. This work will be of interest to researchers and environmental health practitioners involved in the assessment of vibration complaints, as well as to policy makers, planners, and consultants involved in the design of buildings and railways.
The work of the Committee on Aviation Environmental Protection and the Development of International Noise Standards
Authors: Hupe Jane
Published: May 2013

Environmental Protection is one of the Strategic Objectives of ICAO. The overall aim is to minimize the adverse environmental effects of global civil aviation activity. One of the key objectives is to establish noise Standards to limit and reduce the number of people affected by aircraft noise. This mandate is carried out by the Committee on Aviation Environmental Protection (CAEP), which, as a technical committee of the ICAO Council, is a recognized international forum of environmental experts from both member and observer States, intergovernmental organizations, including airlines, aircraft and engine manufacturers, airports, environmental non-governmental organizations, and UN bodies. ICAO has set International Standards for aircraft noise certification since the 1970s, and the purpose of this talk is to describe the process of developing these Standards while providing some details on recent developments, including the key outcomes of three years’ worth of research leading up to the ninth meeting of the CAEP.
Setting noise stringency by international consensus
Authors: Cousineau Yves R.
Published: May 2013

The paper will evoke the background of aviation noise and examine the international consensus process used to set aircraft noise stringency requirements and present the role of controlling the noise at the source within the context of the overall community noise issue. The paper will also examine the role of technology in this process and examine the growing interdependencies of noise reduction technology on CO2 emissions, and on other emissions that impact air quality.
Multi-resonance transduction near acoustic Brillouin zone in microscale ferroelectric
Authors: Ostrovskii Igor , Cremaldi Lucien
Published: May 2013

Excitation of the acoustic plate waves (PAW) in ferroelectric wafers with microscale domains and nanoscale interdomain walls is investigated theoretically and experimentally. The periodically poled structures were fabricated in the Z-cut 0.5-mm-thick LiNbO3 wafers. Rf-current applied along the X-axis generates PAW in the fabricated multidomain acoustic superlattices having stop-bands and acoustic Brillouin zones. Two main effects are observed. First, a frequency of maximum acoustic amplitude does not coincide with the domain resonance frequency when a half-wavelength equal to domain length. Second, instead of known single-frequency domain resonance such as in bulk crystals, the series of two or more transduction resonances do exist. The theory, simulation, and experiments allow concluding that the transduction multi-resonances occur due to ultrasound diffraction by the interdomain nano-walls when the acoustic wavelength is close to multidomain period; it happens near acoustic Brillouin zone boundaries. Since different PAW-modes may be excited, the transduction multi-resonances appear at different frequencies. For example, 300-micron multi-domain structure in LiNbO3 demonstrates multiple transduction peaks in the frequency range of 5.6 to 8.3 MHz, just for lowest four symmetric and antisymmetric PAW modes. The experimental results are in agreement with theory. The findings may be applied for designing new MEMS and therapeutic ultrasonic transducers.
A physical model for predicting the sound speed and attenuation coefficient in Titan's atmosphere based on Cassini-Huygens data
Authors: Petculescu Andi
Published: May 2013

NASA and ESA are discussing plans for a collaborative mission to use montgolfieres to gather long-duration data in Titan’s atmosphere. Acoustic sensors can listen for thunder, bolide explosions, wind noise, cryo-volcanoes, and many other phenomena. This emphasizes the need for accurate acoustic predictions for Titan. In 2005, during the descent of the Huygens probe on Titan, an active ultrasonic sensor measured the speed of sound over the last 12 km. Using the ambient pressure, density, temperature, and methane concentration measured by Huygens as inputs, as well as temperature- and pressure-dependent transport parameters extracted from NIST, a theoretical model has been developed to predict the sound speed and attenuation coefficient in Titan's atmosphere. Based upon non-ideal equations of state, the sound speed predictions agree quite well with Huygens measurements in the lower troposphere. The effect of measured zonal winds on tropospheric propagation is presented via ray-tracing, showing quiet zone predictions. The model can be extended to the upper atmospheric layers (since ambient data are available); nevertheless care must be taken to account for altitude dependent processes such as winds, clouds, aerosols, chemistry, gravity waves, etc. in order to increase the accuracy.
Photo-acoustic and ultrasonic investigation of the mixtures of water and several glycols
Authors: Żwirbla Wioletta , Linde Bogumil B. , Skrodzka Ewa B.
Published: May 2013

In the paper, the results of the ultrasonic velocity and absorption measurements were presented, as well as the thickness the “ro” in water mixtures the polyethylene glycols (PEG-s), the ethylene glycol and diethylene glycol. The experiments were provided in the temperature range from 291.15 to 303.15 K for whole molar fraction. Adiabatic compressibilities were calculated from Laplace's equation based on the experimental results obtained. Variations of these values with concentration and temperature were studied. Structural interactions and the formation of a compact pseudostable structure at very low concentrations of ethylene glycol and polyethylene glycols were observed. The plots of the adiabatic compressibility versus the mole fraction of PEG and EG display two characteristic points at low concentrations: the intersection of the isotherms and their minimum. Such relations between adiabatic compressibility, concentration and temperature are usually attributed to the formation of pseudo-stable molecular structures. To formulate a model of local structures present in the investigated molecular systems it is indispensable to get an insight into hydration of molecules and the formation of hydrogen bonds. Therefore, the attention was focused particularly on these problems.
Experiments on authenticity and naturalness of binaural reproduction via headphones
Authors: Fels Janina , Oberem Josefa , Masiero Bruno
Published: May 2013

Binaural stimuli presented via headphones need to be plausible in localization and sound coloration for a successful reproduction of an acoustic scene, especially for experiments on auditory selective attention. The goal is to provide artificially generated acoustic scenes in a way that the difference between a real situation and an artificially generated situation has no influence in psychoacoustic experiments. The quality and reliability of binaural reproduction via headphones comparing two different microphone setups (miniature microphone in open dome and ear plug) used for individualized head-related transfer functions and headphone transfer function measurements is analyzed. Listening tests are carried out focusing on authenticity, naturalness, and distinguishability in a direct comparison of real sources and binaural reproduction via headphones. Results for three different stimuli (speech, music, pink noise) are discussed. Furthermore, approaches to perform experiments on auditory selective attention with binaural reproduction versus dichotic reproduction are made.
Perceptual equalization of artifacts of sound reproduction via multiple loudspeakers
Authors: Seeber Bernhard U. , Hafter Ervin R.
Published: May 2013

Several techniques for reproducing spatial sounds via multiple loudspeakers have been developed in recent years. A key problem for such techniques are comb filter effects caused by the uncertainty of the receiver position when playing coherent sounds from multiple loudspeakers (spatial aliasing). Here we studied if panning between two closely spaced loudspeakers can create a virtual source that resembles that of a true source. This requires not only that panned direction and speaker position correspond, but also that source width, loudness, timbre, and temporal aspects are reproduced without perceptual error. A listening experiment in an anechoic chamber showed that panned sources differ primarily in loudness and timbre from a real source at the panned location. The artifacts are caused by effects of the head, and we investigated if they can be compensated by filtering the sounds. Compensation filters were derived from simulations of the sound field at the ears. Listening tests showed that compensation filters reduced panning errors to be nearly inaudible and level roving or reflections in the reproduction room made errors inaudible. We conclude that a simple equalization is sufficient to render panned sources from nearby speakers perceptually equivalent to real sources.
Training Korean second language speakers on English vowels and prosody
Authors: Shin Dong-Jin , Iverson Paul
Published: May 2013

This study trained 36 Korean L2 speakers on vowel identification and prosody recognition (focus and lexical stress), with the aim of investigating the extent to which training improves general speech perception abilities or specific underlying processes. Vowel training was accomplished with a high-variability identification training technique (multiple talkers and words), and prosody training was accomplished using a category discrimination task in which they needed to choose sentences based on focus or words based on syllable stress. The results demonstrated that both trainers reduced vowel epenthesis and improved syllable stress perception, vowel training improved vowel identification more, and prosody training better improved focus perception in sentences. Both types of training can thus work in a complementary fashion to improve overall speech recognition.
Estimation of vocal tract area functions in children based on measurement of lip termination area and inverse acoustic mapping
Authors: Bunton Kate , Story Brad H. , Titze Ingo R.
Published: May 2013

Although vocal tract area functions for adult talkers can be acquired with medical imaging techniques such as magnetic resonance imaging (MRI), similar information concerning children’s vocal tracts during speech production is difficult to obtain. This is largely because the demanding nature of the data collection tasks is not suitable for children. The purpose of this study was to determine the feasibility of mapping formant frequencies measured from the [i, ae, a, u] vowels produced by three children (age range 4 to 6 years), to estimated vocal tract area functions. Formants were measured with a pitch-synchronous LPC approach, and the inverse mapping was based on calculations of acoustic sensitivity functions [Story, J. Acoust. Soc. Am. 119, 715–718]. In addition, the mapping was constrained by measuring the lip termination area from digital video frames collected simultaneously with the audio sample. Experimental results were augmented with speech simulations to provide some validation of the technique. [Research supported by NIH R01-DC011275.]
Articulatory phonetics of coronal stops in monolingual and simultaneous bilingual speakers of Canadian French and English
Authors: Brajot Francois-Xavier , Mollaei Fateme , Callahan Megan , Klein Denise , Baum Shari R. , Gracco Vincent L.
Published: May 2013

Previous studies of bilingual speech production have relied on individuals whose age of acquisition of their second language varies. In the proposed research, we take advantage of the unique multilingual environment of Montreal and examine speech production in individuals who have acquired two languages from birth and compare the results to monolingual speakers. Electromagnetic recordings of single-word productions were carried out on three groups of female Canadian speakers (French monolingual, English monolingual, French-English simultaneous bilingual). Spectral moment and formant transition analyses of coronal burst segments showed cross-linguistic differences across vowel contexts. Tongue place of articulation and shape likewise indicated cross-linguistic differences in static articulatory positions. Kinematic analyses further identified language-specific movement patterns that helped clarify certain results from the acoustic analyses, namely that spatiotemporal characteristics of coronal articulation help enhance vocalic dimensions important to the respective language. Similar patterns were observed among the bilingual subjects, with the notable exception that acoustic and kinematic spaces narrowed considerably, resulting in reduced overlap between languages. It appears that simultaneous bilingual speakers not only follow language-appropriate articulatory and acoustic patterns, but further minimize areas of cross-linguistic convergence otherwise found among monolingual speakers.
A developmental study of vowels spoken in syllables and in sentence context
Authors: Hubbard Daniel J. , Kiefte Michael , Hossain Shaikat , Assmann Peter F.
Published: May 2013

This study examined the effects of context on the production of vowels spoken by children of different ages in isolation and in a carrier sentence. Vowels were extracted from a database of hVd syllables produced by 207 native English talkers from the North Texas region, ranging in age from 5 to 18 years with approximately equal numbers of males and females. Preliminary analysis of a subset of the database (around 25% of talkers) showed a systematic reduction in vowel duration with increasing age for syllables in isolation. Vowels in sentence context were on average 30% shorter than in isolated syllables, and durations were less closely linked to age group. Formant frequencies (F1–F3) showed similar patterns for vowels in isolated syllables and sentences, and decreased as a function of age as expected. However, measures of formant movement across the vowel (from 20 to 80% of the vowel duration) revealed increased F1 and F2 movement for syllables in isolation compared to those produced in carrier sentences. A comprehensive analysis of the database will be presented and implications for vowel recognition will be discussed.
An ultrasound study of the acquisition of North American English /ɹ/
Authors: Magloughlin Lyra V.
Published: May 2013

I report an acoustic and articulatory study of North American English /ɹ/ production in typically developing English-speaking children during early and later-stage acquisition. North American English /ɹ/ is of interest in adult populations because it exhibits acoustic stability (e.g., low F3) despite considerable articulatory variability both within and between speakers [Delattre and Freeman (1968)]. North American English /ɹ/ is also often one of the last sounds to be acquired by children [Smit (1993), Schriberg (1993)], especially in prevocalic position (Smit et al. (1990), McGowan et al. (2004)]. Tiede et al. (2011) have argued that children might attempt different vocal tract configurations during acquisition, particularly in contexts where the articulatory demands are greater. While there is a growing body of literature on articulatory variability in adult production of /ɹ/ [e.g., Mielke et al. (2010), Campbell et al. (2011)], there remains virtually no articulatory data on typically developing children’s production during acquisition. This study uses ultrasound imaging to investigate the articulations of four typically developing English-speaking children, aged between 3 and 6 years, during production of familiar lexical items. Children’s early-stage articulations are examined and compared with their later-stage productions, and with adult variability patterns.
Exploring auditory aging can exclusively explain Japanese adults’ age-related decrease in training effects of American English /r/-/l/
Authors: Kubo Rieko , Akagi Masato
Published: May 2013

Age-related decrease in training effect was shown by training of American English /r/-/l/ contrasts on Japanese speakers. This study examined whether the decrease can be explained exclusively by auditory aging, or other, compensatory cognitive processing should be taken into account. Japanese speakers aged 60’s participated the experiment. Hearing threshold and spoken word perception test of participants’ first language were used to estimate their auditory aging. The word perception test was composed of low-familiar words, high-familiar words, and mono syllables. The audiograms showed low threshold at high frequencies. The result of the perception test showed that low intelligibility for phonemes with high frequency or short duration, and confusion between contracted sounds and basic sounds. These were particular for low-familiar words and mono syllables. These results suggest that participants had auditory aging emerging as high frequency loss and time-frequency-resolution degradation. Nonetheless, the acoustic features to distinguish /r/ and /l/ have long duration, low frequencies and wide frequency distance which are supposed to be unaffected by these auditory aging. The effect of word familiarity suggested compensatory cognitive processing involved. These suggest that age-related decrease cannot be explained exclusively by auditory aging, compensatory cognitive processing should be taken into account.
Individual variability in phonetic convergence of vowels and rhythm
Authors: Rao Gayatri , Smiljanic Rajka , Diehl Randy
Published: May 2013

Phonetic convergence (PC) has been demonstrated for segmental (vowels, voice onset time) and suprasegmental (stress, intonation) properties [Nielsen (2008), Delvaux and Soquet (2007), Phillips and Clopper (2010), Rao, Smiljanic, and Diehl (2011)]. Since PC is subject to large individual differences [Ni Chiosáin (2007)], the current study examined individual variability in PC in both segmental and suprasegmental domains for native speakers of American English. Six female and six male pairs read CVC syllables and a short paragraph before and after an interactive map task. For each dyad, convergence in vowels was measured using formants and the cosine similarity metric for individual vowels and for the entire vowel space. Convergence in rhythm was measured using the centroid of the envelope modulation spectrum [EMS + centroid, Rao and Smiljanic (2011)]. Overall, speaker pairs converged to different extents in both measures. Vowel type, dialect background, and gender were found to influence the degree of convergence. In general, men were more likely to converge in rhythm whereas women were more likely to converge in vowels. This supports the findings that gender-based differences in convergence are due to perceptual sensitivity to indexical features [Nami et al. (2002), Babel (2009)] and particular sound features in spoken utterances.
Interaction of long-term acoustic experience and local context information on the perceptual accommodation of talker variability
Authors: Zhang Caicai , Peng Gang , Wang William Shi-Yuan
Published: May 2013

How do listeners recover speech content from acoustic signals, given the immense variability between talkers? In this study, two experiments were conducted on Cantonese level tones, comparing the perception of multi-talker speech stimuli in isolation and within a speech context. Without prior knowledge of a talker’s pitch range, listeners resort to the population-average pitch range as a default reference for perception. This effect is attested by the significant correlation between the distance from population-average pitch range and identification accuracy in the isolation condition (r = -0.24, p < 0.01). The closer a talker’s pitch range is to the population-average, the higher the identification accuracy is. The population-average reference is gender-specific, showing separate accommodation scales for female and male talkers. Such default reference is presumably built from one’s long-term acoustic experience, reflecting the dense distribution of talkers in a community whose pitch is close to the population-average. Above the effect of long-term experience, the presence of a speech context allows listeners to tune to talker-specific pitch range, boosting the identification accuracy from 43% (in isolation) to 86%. Our findings demonstrate that listeners have built-in knowledge of population-average pitch and can shift from the default reference to talker-specific reference with the facilitation of context information.
Voice-onset time in infant-directed speech over the first year and a half
Authors: Cropsey Evamarie , Gamache Jessica , Bergeson Tonya , Dilley Laura
Published: May 2013

Previous research in small-N studies has indicated conflicting findings regarding whether mothers modify voice-onset time (VOT) of word-initial stop consonants in speech to infants compared to speech to adults, as well as the nature of any such modification. In a large-scale study, VOT was measured for voiced and voiceless stop consonants in speech of 48 mothers of infants in one of four cross-sectional age groups (0;3, 0;9, 1;1, 1;8) when they read a phonetically controlled storybook to their infant (ID speech) or an adult (AD speech). VOT measurements showed enhanced clarity (i.e., longer VOTs) in ID speech compared with AD speech for voiceless stop consonants only. An effect of infant gender was also found, showing that enhanced clarity was only produced by mothers of female infants (N = 19). Infant age was not found to be a significant factor in VOT production. The results have implications for understanding the nature of linguistic development in young children, specifically by elucidating factors apparently related to phonetic modification for clarity, including speech style and gender. [Work supported by NIH-NIDCD grant R01DC008581.]
Does compensation in auditory feedback require attention?
Authors: Alsius Agnes , Mitsuya Takashi , Munhall Kevin G.
Published: May 2013

When speakers receive auditory feedback with a real-time perturbation of formant structure, they hear themselves produce a vowel slightly different form the one intended. In response, they spontaneously change the formant structure to make the feedback more consistent with the intended sound. This compensatory behavior was reported to be automatic [Munhall et al. (2009)] because speakers are not able to suppress it even when they are informed about the perturbation and are instructed not to change their articulation. However, whether and to which extent attentional resources are utilized for this behavior have not been directly investigated. In the current study, speakers performed a speech production task where they pronounced a monosyllable whose formant structure was perturbed, while concurrently performing another task (i.e., dual-task paradigm). The preliminary results showed that, when attention was diverted to an unrelated auditory detection task, the magnitude of compensation remained the same as in the single task condition. Follow-up experiments will manipulate the nature and difficulty of the concurrent task to examine whether compensation in speech production is affected, and if so, what levels of the error feedback system are more susceptible to attentional manipulations.
Speech sensorimotor learning through a virtual vocal tract
Authors: Berry Jeffrey J. , North Cassandra , Meyers Benjamin , Johnson Michael T.
Published: May 2013

Studies of speech sensorimotor learning often manipulate auditory feedback by modifying isolated acoustic parameters such as formant frequency or fundamental frequency using near real-time resynthesis of a participant’s speech. An alternative approach is to engage a participant in a total remapping of the sensorimotor working space using a virtual vocal tract. To support this approach for studying speech sensorimotor learning, we have developed a system to control an articulatory synthesizer using electromagnetic articulography data. Articulator movement data from the NDI Wave System are streamed to a Maeda articulatory synthesizer. The resulting synthesized speech provides auditory feedback to the participant. This approach allows the experimenter to generate novel articulatory-acoustic mappings. Moreover, the acoustic output of the synthesizer can be perturbed using acoustic resynthesis methods. Since no robust speech-acoustic signal is required from the participant, this system will allow for the study of sensorimotor learning in any individuals, even those with severe speech disorders. In the current work, we present preliminary results that demonstrate that typically functioning participants can use a virtual vocal tract to produce diphthongs within a novel articulatory-acoustic workspace. Once sufficient baseline performance is established, perturbations to auditory feedback (formant shifting) can elicit compensatory and adaptive articulatory responses.
Improvement of accuracy of 3D sound space synthesized by real-time “SENZI,” a sound space information acquisition system using spherical array with numerous microphones
Authors: Sakamoto Shuichi , Hongo Satoshi , Okamoto Takuma , Iwaya Yukio , Suzuki Yôiti
Published: May 2013

We proposed a sensing method of 3D sound-space information based on symmetrically and densely arranged microphones mounted on a solid sphere. We call this method SENZI [Sakamoto et al., ISUC2008 (2008)]. In SENZI, the sensed signals from each of the microphone is simply weighted and summed to synthesize a listener's HRTF, reflecting the listener's facing direction. Weighting coefficients are calculated for individual listeners based on their HRTFs. These coefficients are changed according to the listeners' head movement, which is known to provide important dynamic perceptual cue for sound localization. Therefore, accurate sound space information can be presented to unlimited number of listeners not only beyond the distance but also beyond the time. Recently, we realized this method as a real-time system using a 252-ch spherical microphone array and FPGAs. By using this system, accurate sound space information up to around 10 kHz can be synthesized to any listeners. However, the SNR of microphones affected to the accuracy of synthesized sound-space information, especially under low frequency region. To avoid the effect, we used condition numbers as an index to synthesize accurate sound-space information in the low frequency region.
Spatial audio coding with spaced microphone arrays for music recording and reproduction
Authors: Politis Archontis , Laitinen Mikko-Ville , Pulkki Ville
Published: May 2013

Spaced microphone arrays are commonly used in multichannel recording of music, due to their inherent quality of natural incoherence between the surround channels at reproduction, at the expense of accurate localization. Recent methods in parametric spatial audio coding, such as Directional Audio Coding, exploit coincident microphone patterns to extract directional information and reproduce it in a perceptually optimal way. In this study, we present how Directional Audio Coding can be adapted for spaced arrays, offering improved localization cues at reproduction, without compromising the qualities of the spaced microphone recording techniques. Examples are presented for some well-established array configurations.
Time-varying three-dimensional mapping of internal waves during the Shallow Water 2006 experiment
Authors: Badiey Mohsen , Wan Lin , Song Aijun
Published: May 2013

Formation and propagation of internal waves have recently become of interest to ocean acousticians, since the propagation of internal waves in shallow water waveguide plays an important role in intensity fluctuations of acoustic signals [J. Acoust. Soc. Am. 112(2), 747–760 (2007)]. Modeling the acoustic field in these regions requires detailed knowledge of sound speed and its spatial and temporal variability resulting from propagating internal waves. Although satellite imagery can provide snapshots of the surface impressions of the internal waves, due to low sampling in time (limited images in each orbit) other techniques to obtain the time varying, three-dimensional (3D) internal wave field are desirable. An example to obtain a time-varying, 3D internal wave field is presented in this paper. The internal wave fine structure is reconstructed using simultaneous measurement of temperature data using thermistor arrays and the surface impressions of a moving internal wave packet using a ship’s radar during the Shallow Water 2006 experiment (SW06). The parameters of the internal wave train, such as wave speed, propagation direction, and amplitude of the first wave front, are determined. The resulting temperature field induced by the internal waves is used as environmental input to a 3D acoustic model to study the effects of internal wave on acoustic propagation. [Work supported by ONR322OA.]
The effect of surface and linear internal waves on higher order acoustic moments in shallow water
Authors: Raghukumar Kaustubha , Colosi John A.
Published: May 2013

Acoustic fields in shallow water have a statistical nature due to complex, time-evolving sound speed fields, and scattering from rough boundaries. Previously, coupled-mode transport theory [Raghukumar and Colosi (2012)] was applied to high frequency acoustic fluctuations in an environment typical of the Shallow Water 2006 (SW06) experiment on the New Jersey continental shelf. As a consequence of the strong adiabatic component in SW06 propagation, a hybrid approach was used to calculate mode coherences where mode energies from the Dozier-Tappert approach were combined with adiabatic phase terms. Mode energies, coherences and acoustic intensities were examined, and it was found that internal and surface waves preferentially couple low and high modes respectively. Here, we extend that study to include higher moments such as scintillation index and shift focus to modes that are coupled by both internal and surface waves. Oceanographic and sea surface measurements are used to constrain the internal wave and sea surface models. The relative importance of linear internal waves and surface scattering effects are studied using transport theory and Monte Carlo simulations.
The effects of internal tides on phase and amplitude statistics in the Philippine Sea
Authors: Colosi John A. , Chandrayadula Tarun , Coby Weston , Fischer Jacob , Dushaw Brian D. , Dzieciuch Matthew A. , Worcester Peter F.
Published: May 2013

Moored oceanographic sensors and satellite altimetry has revealed energetic diurnal and semi-diurnal internal tides in the Western Philippine Sea. Because the internal tides have a complex spatio-temporal pattern and large vertical displacements, these waves have the potential for causing strong acoustic variability. This talk will present a tidal analysis of signal fluctuations from the PhilSea09 experiment in which broadband signals with a center frequency of 275 Hz and a bandwidth of 50 Hz were transmitted at the sound channel axis to a large aperture vertical array 180-km distant. Signal phase and amplitude statistics along distinct branches of the observed wavefronts will be analyzed and compared to ray-based model predictions using internal tide information obtained from moored oceanographic instruments at the source and receiver. Key issues are the acoustic effects of the internal tide nonlinearity, temporal stability, high mode structure, and complex horizontal interference patterns.
Comparison of transport theory predictions with measurements of the decrease in shallow water reverberation level as the sea state increases
Authors: Thorsos Eric I. , Yang Jie , Elam W. T. , Henyey Frank S. , Li Fenghua , Liu Jianjun
Published: May 2013

Transport theory has been developed for modeling shallow water propagation and reverberation at mid frequencies (1–10 kHz) where forward scattering from a rough sea surface is taken into account in a computationally efficient manner. The method is based on a decomposition of the field in terms of unperturbed modes, and forward scattering at the sea surface leads to mode coupling that is treated with perturbation theory. Reverberation measurements made during ASIAEX in 2001 provide a useful test of transport theory predictions. Modeling indicates that the measured reverberation was dominated by bottom reverberation, and the reverberation level at 1 and 2 kHz was observed to decrease as the sea surface conditions increased from a low sea state to a higher sea state. This suggests that surface forward scattering was responsible for the change in reverberation level. By modeling the difference in reverberation as the sea state changes, the sensitivity to environmental conditions other than the sea surface roughness is much reduced. Transport theory predictions for the reverberation difference are found to be in good agreement with measurements. [Work supported by the U.S. Office of Naval Research, Ocean Acoustics.]
Designing a stackable diffusor/absorber tailored to a violin and cello practice room
Authors: Nam Myoung woo , Lee Kyogu , Case Alexander U.
Published: May 2013

As distinct from a much larger concert hall, the typical practice room directs added acoustic emphasis to small room challenges such as room resonances and unwanted reflections. Although rich reverberation is not easily achieved in a small space, the proposed diffusor/absorber seeks to make practice more acoustically comfortable and rewarding. The treatment is designed to attenuate the spectral portion of the violin and cello sound that engages the room resonances. When musicians play violin and cello, omni-directional low frequencies are primarily produced in lower elevation of the room, while more directional higher frequencies of interest to the performer are directed more to upper area. This diffusor/absorber is designed to provide more absorption for bottom area and more diffusion for upper area. In this configuration, the diffusor/absorber gives comfortable acoustical conditions for musicians to practice. Based on sound propagation characteristics [J. Meyer, “The sound of the orchestra,” J. Audio Eng. Soc. 41(4) (1993)] and formant information of violin and cello [M. Nam and K. Lee, “Analyzing string instrument formant,” in Proceeding of Acoustical Society of Korea Conference (2011)], this design proposes a moveable acoustic panel-box suitable for a typical musician's home practice room and a small sized recording studio.
Can we use the standard deviation of the reverberation time to describe diffusion in a reverberation chamber?
Authors: Lautenbach Margriet , Vercammen Martijn
Published: May 2013

It is generally assumed that the limited diffusion properties of reverberation rooms, especially with a strongly sound absorbing sample, is the main reason for the bad reproducibility values for the sound absorption between laboratories. Reverberation rooms should be made much more diffuse to reduce the inter laboratory differences. Although there are practical ways to achieve this, it is most important that there will be a requirement in the ISO 354 standard on the diffusing quality of the sound field. One possibility is to use the standard deviation of the reverberation time for different source-microphone combinations in the reverberation room. Measurements are performed to investigate the influence of different settings of a reverberation room on the standard deviation of the reverberation time, compared to the theoretical standard deviation. This is done with the interrupted impulse method and the integrated impulse method. The results will be presented in this paper. The usefulness of this qualification method for the ISO standard will be discussed.
A new third generation time variant electro-acoustic enhancement system
Authors: Barbar Steve
Published: May 2013

This paper describes the hardware and software implementation in a new generation of time variant electronic acoustic enhancement systems designed for use in medium and large sized venues. Examples of currently installed systems and applications will be discussed, as well as capabilities for sound file storage and playback, multi-channel film surround sound, 2D effects panning, and 3D live tracking.
Dah-You Maa: Most senior academic brother
Authors: Blackstock David T.
Published: May 2013

F. V. Hunt’s ONR-supported acoustics lab at Harvard turned out 30 PhD graduates after WW II. As one of those students in the late 1950s, I gradually became aware that Hunt had had a prewar group of graduate students as well. Leo Beranek was Hunt's first Ph.D., Dah-You Maa his second (both in 1940). Maa’s two 1939 JASA articles on room acoustics, one coauthored with Beranek and Hunt, were benchmark papers of the day. I became fascinated with Maa’s story, partly because he seemed so completely unreachable. He had returned to China during the war; afterward the Cold War intervened. I finally met my much older academic brother in 1980, at the 10th ICA in Sydney, Australia. Thus began a warm and rewarding relationship. In 1987, he began representing China on the International Commission on Acoustics, and for 7 years, we saw each other annually at Commission meetings. I learned of his work on nonlinear standing waves, a problem in which I too shared a keen interest. The high point was at the 14th ICA in Beijing. I was finally able to see his laboratory and meet his doctoral student Ke Liu. A memorable dinner followed that evening.