bluuebunny/crossref_metadata_2025 huggingface dataset:
On the correlation between the acoustic anisotropy and the magnetic susceptibility anisotropy of the rocks.
Authors: Lebedev Andrey , Bredikhin Vladimir , Bretshtein Yuri
Published: October 2010

Using resonant acoustic spectroscopy technique, we studied several rock samples. Acoustic data were compared with the data for magnetic susceptibility of the same samples. The correlation between the acoustic anisotropy and the magnetic susceptibility anisotropy has been revealed for samples of metamorphic and sedimentary rocks. The existence of this correlation points to the same origin for both magnetic and acoustic anisotropy. The origin is the rock texture created during long tectonic history of the rock samples analyzed. The value of acoustic anisotropy allows evaluating the rock fracturing or the amplitude of tectonic stresses. Under additional calibration, it makes possible the use of the magnetic susceptibility value as a measure of tectonic processes intensity. The latter can be very useful to create express diagnostics of tectonic history in the field conditions.
A large-scale study on meaning-oriented auditory training with single versus multiple talkers.
Authors: Tye-Murray Nancy , Sommers Mitchell , Barcroft Joe
Published: October 2010

In their research review, Sweetow and Palmer (2002) concluded that the question of whether auditory training can be effective remains largely unanswered, primarily due to numerous methodological flaws in previous investigations. In light of this situation, we initiated a large-scale study to assess the benefits of auditory training while controlling for many of the methodological limitations pointed out by Sweetow and Palmer. The study also was designed to assess the effectiveness of using activities that are meaning-oriented while comparing the impact of two versions of the program—single-talker and multiple-talker. Participants include both hearing-aid users and cochlear implant recipients. Participants complete 12 1-h lessons during training. Each lesson includes spoken input at a variety of levels of linguistic analysis, including word, sentence, and discourse. Data will be presented for the two test groups. Analyses of both traditional (e.g., phoneme and word discrimination) and novel (perceptual effort) assessments indicate that the auditory training program is effective. Initial comparison of the single- and multiple-talker training conditions suggest that for the multiple-talker testing conditions, which most closely simulate real-world speech perception demands, training with multiple talkers is generally better than single-talker training.
Effects of reducing speech audibility on signal-to-noise-ratio loss for hearing-impaired listeners.
Authors: Nelson Peggy B. , Nie Yingjiu , Anderson Elizabeth Crump , Katare Bhagyashree
Published: October 2010

Listeners with sensorineural hearing loss show reduced benefit from fluctuating compared to stationary maskers and experience apparent signal-to-noise-ratio loss when compared to listeners with normal hearing. Previously [Nelson et al. ASA Baltimore (2010)] we tested normal-hearing and hearing-impaired listeners at similar reduced audibility levels. Listeners with normal hearing and hearing loss were presented IEEE sentences at a range of overall levels (from 30 to 80 dB sound pressure level), signal-to-noise ratios, and low-pass filter settings, resulting in a range of signal AIs that varied from 0.1 to 0.95. For the normal-hearing listeners, there was a very systematic relationship between AI and performance; the relationship between AI and performance was less systematic for listeners with hearing loss. In the current project we tested each listener over a wide range of AIs and report the change in performance with increasing AI for individual listeners with normal hearing and hearing loss. Implications for hearing aids will be described. [Work supported by NIDCD R01-DC008306.]
Acoustic metamaterials based on phononic crystals.
Authors: Sanchez-Dehesa J. , Torrent D.
Published: October 2010

This talk will review recent results on the topic of sound propagation through periodic arrays of sonic scatterers embedded in a fluid or a gas. These structures, which are called phononic crystals, define in the homogenization limit (i.e., for lattice separations much lower than the sound wavelength) a class of acoustic metamaterials with extraordinary properties. For example, they are solid structures that are used to engineer effective fluid-like systems with anisotropic dynamical mass density, a property that can be tailored by changing the parameters of the structure and the material composition of scatterers. A homogenization method based on multiple scattering theory has been developed and semianalytical expressions for the effective acoustic parameters will be given. By using these expressions it is easy to design novel refractive devices like gradient index sonic lens with a perfect match of impedance with the background. Results for a gradient index lens made of aluminum cylinders in air will be presented. Moreover, metamaterials with mass anisotropic have also been proposed to build broadband acoustic cloaks and a new type of crystals named radial sonic crystals, which are radially periodic structures that verify the Bloch theorem. [Work supported by ONR and by MICIIN of Spain.]
Constrained negative stiffness metamaterials.
Authors: Kashdan Lia B. , Haberman Michael R. , Wilson Preston S. , Seepersad Carolyn Conner
Published: October 2010

Acoustics-oriented metamaterial research has focused primarily on the use of subwavelength resonant structures to elicit unconventional macroscale properties such as negative mass, anisotropic density, and negative stiffness. Unfortunately, reliance on resonant behavior limits the usefulness of these types of metamaterials to a narrow band of frequencies. One intriguing manifestation of negative stiffness, however, does not require resonant behavior and is therefore useful over a broader range of frequencies. This type of negative stiffness relies on constrained bistable structures and is known as constrained negative stiffness (CNS). The present work investigates the use of CNS mechanisms for vibration isolation and acoustic wave attenuation. A linearized analytical model of a constrained buckled beam structure is presented to predict system behavior and stability, and investigate the fundamental physical behavior leading to increased energy absorption. Experimental studies are then shown confirming model predictions. Finally, a 1-D candidate acoustical metamaterial containing CNS inclusions is modeled and analyzed.
Source range and depth estimation using passive sonar, horizontal arrays, and knowledge of the environment.
Authors: Bissinger Brett E. , Jemmott Colin W. , Miller David J.
Published: October 2010

Target detection, classification, localization, and tracking (DCLT) using horizontal arrays and passive sonar is a well-studied problem. Good detection results can be obtained using narrow beams that maximize signal to noise ratio. Beamforming also provides azimuth angle, but is generally not reliable for range and depth estimation. Matched field processing (MFP) makes use of environmental knowledge to predict the received signal at the array, and correlates predicted and received signals to estimate target range and depth. However, poor or inaccurate environmental knowledge degrades MFP performance, and in general, MFP suffers from high side lobes or ambiguity in the range/depth probability surface. Received signal amplitude statistics have been used to estimate source depth, but the method has not been studied extensively to date. Recently several methods have been developed involving received signal amplitude statistics predicted using environmental parameter statistics to construct statistically valid descriptions of the environment, which were then fed to an ocean acoustic propagation model (i.e., Monte Carlo simulation). Performance of the algorithms has been evaluated using data from the Swellex-96 experiment. [Work sponsored by ONR Undersea Signal Processing.]
Control strategies and mechanisms for active control of sound transmission into a cabin enclosure.
Authors: Jin Guoyong , Shi Shuangxia , Liu Zhigang
Published: October 2010

An analytical study of active control of sound transmission into a cabin enclosure is presented. A cabin enclosure with four acoustically rigid walls and two flexible plates is considered as the analytical model. Two types of actuators are used, i.e., acoustic actuators and distributed lead zirconate titanate piezoelectric (PZT) actuators instead of point force actuators. Using the modal acoustic transfer impedance-mobility matrices, the excitation and interaction in the coupled sound transmission system can be described with clear physical significance. With the control system designed to globally reduce the sound field, different control configurations are considered, including the structural actuator on the incident panel, actuator on the receiving panel, acoustic actuator on the cavity, and their combinations. The effectiveness and performance of the control system corresponding to each configuration are compared and discussed. The roles and attenuation mechanisms of each type of actuator are of particular interest, and desirable placements of structural actuators in terms of total potential energy reduction are also discussed.
Large scale passive acoustic data management.
Authors: Wall Carrie C. , Mann David A.
Published: October 2010

Passive acoustic recording systems can generate large amounts of data, especially given the increasing capability of inexpensive flash memory. DSGLab, an open-source database and data analysis system implemented with MATLAB and a portal to MYSQL, was created to handle large amounts of raw data collected by dozens of acoustic recorders over periods up to a year. Each recorded data file is tagged with header information including latitude, longitude, depth or altitude, timestamp, sample rate, and calibration, among other metadata variables, and uploaded to the database. This information allows all files in the database to be queried based on, for example, location (latitude, longitude, depth) and time (date, hour). Then the data analysis section processes the desired selection of files according to a user-specified signal processing chain, which does not require prior programming knowledge, and returns the results to a database and to individual files. The signal processing results can then be quickly browsed with the data viewer, providing a time-series of the processed data results, a map of recording locations, and facilitating retrieval of individual file timestamps and original raw data for quality control. The system is designed to allow inter-laboratory collaboration and data sharing. Examples using glider data are provided.
A new method for recognition of non-voice sounds that is suitable for searching very large records.
Authors: Neil Boucher , Jinnai Michihiro , Pavan Gianni
Published: October 2010

An innovative non-voice sound recognition system based on a new similarity scale called the geometric distance has been developed. It has been purpose-designed for searching terabyte-sized files for wildlife recordists. Initially this method has been used for analyzing continuous recordings of rare parrots in Australia. More recent work has extended its applications to other birds, bats, frogs, and marine animals. The software can search for multiple reference sounds and multiple species in a single pass. It has been demonstrated to achieve recognition accuracy comparable to a human expert.
Electronic sonar system.
Authors: Barroeta Carlos , Ortiz Floriberto R. , Novoa Colin Juan Francisco , Lopez Rodrigo C.
Published: October 2010

This is about a sonar system with specific characteristics. This sonar is able to measure up to 3 m and work is being done to get the best frequency and time period. The gate should be closed if the time is larger than the size of the sonar capacity. T1 is the time for the ongoing signal and T2, the total time is equal to 2T1. The system will be tested for many different frequencies beginning with a frequency of 15 000 kHz.
Experimental analysis of laptop fan noise radiation by acoustic source decomposition and inverse boundary element methods.
Authors: López Rodríguez Flor , Orduña Bustamante Felipe , Pérez López Antonio
Published: October 2010

Measurements are presented of fan noise radiation of a complete laptop system in a hemi-anechoic chamber using different microphone arrays. The analysis of sound radiation is performed by means of acoustic source decomposition and inverse boundary element methods. These methods allow determination of equivalent source distributions and radiation patterns of the complete laptop environment. Results are extended and validated by comparison with sound intensity mappings and near-field acoustic holography.
Commercial packaging of an optical microelectromechanical systems microphone.
Authors: Kuntzman Michael L. , Kirk Karen D. , Garcia Caesar T. , Onaran Guclu A. , Hall Neal A.
Published: October 2010

A microelectromechanical systems (MEMS) optical microphone has been presented that measures the interference of light resulting from its passage through a diffraction grating and reflection from a vibrating diaphragm. [J. Acoust. Soc. Am. 122, (2007).] In this embodiment, both the diffractive optical element and the sensing diaphragm are micromachined on silicon. Additional system components include a semiconductor laser, photodiodes, and required readout electronics. In our efforts to commercialize this technology for hearing-aids and other applications, a goal has been set to achieve a microphone contained in a small surface mount package (occupying 2 × 2 × 1 mm3 volume), with ultra-low noise (15 dBA) and broad frequency response (20 Hz–20 kHz). Such a microphone would be consistent in size with the smallest MEMS microphones available today, but would have the noise performance characteristics of professional-audio microphones at least 10× larger in size and 10× more expensive to produce. This paper will present several unique challenges in our effort to develop the first surface mount packaged optical MEMS microphone, including the optical and acoustic design of the package. Dynamic models used for simulating frequency response and noise spectra of complete capsules will be presented and compared with measurements performed on recent prototypes.
Standing wave measurements in tubes.
Authors: Cheyne Stanley A. , McDermott Walter C.
Published: October 2010

Sound speed measurements have been made using a standing wave technique for possible inclusion in Project Listen Up! In a previous paper [S. A. Cheyne and W. C. McDermott, “Sound speed measurements in air using a variable sound source and tubes,” J. Acoust. Soc. Am. 125, 2625 (2009)], sound speed measurements in tubes were made using traditional standing wave techniques. A low-cost variable frequency sound source was constructed and used to produce the sound waves. Resonances in the source itself made it difficult to make reliable measurements. Also, it was difficult to detect the tube resonances by simply listening to the resonances with one’s ear. In this work, we have improved the quality of the apparatus to make it easier to generate and detect tube resonances.
Acoustical differences between treble guitar strings of different tension (i.e., gauge).
Authors: Faherty Michael , Aaronson Neil L.
Published: October 2010

The thickness of a guitar string has a complicated effect on the overall sound of the instrument, affecting the degree of inharmonicity in the tone. [Fletcher et al., (1991).] Different players also select strings of certain tensions because of their perceived qualities such as brightness and loudness. The acoustical differences in the sound and sustain of plucked nylon guitar strings as a function of string tension were measured in an effort to quantify these differences. The open string, fifth-fret, and 12th-fret harmonic waveforms of the treble (G, B, and E) strings were studied for sets of strings with different tensions. Only treble strings, made of a monofilament pure nylon strand, were studied. The levels of the first ten harmonics relative to the level of the fundamental were measured for each sound on each string, as well as the duration of the sustain in each case. Patterns in the sustain times and spectra as a function of string gauge will be presented. [Research supported by the Richard Stockton College of New Jersey.]
Noise in the largest Mexican city.
Authors: Beristain Sergio
Published: October 2010

Mexico City is one of the largest cities in the whole world, and so it faces many of the contamination problems such as ozone, garbage, dust, and vibration, among others. Noise has spread along the city far beyond the industrial areas, the airport area which is now within the city limits, or the main traffic streets and fast roads. It can be found in commercial areas trying to attract customers passing by the streets, and also inside large commercial centers, living areas from most economical status, through popular parks and squares, which are supposed to be used for relaxation, but many of them have become commercial and exhibit areas, not to mention in most recreational sites, where people gather to listen high-level sounds.
Road noise simulation as a management tool for redesign of public transport routes in the city of Medellin.
Authors: Murillo Gmez Diego Mauricio , Echeverri Londoño Carlos Alberto , Valencia Hernandez Germán Mauricio
Published: October 2010

In this paper we present the process of road noise simulation as an analytical tool for decision-making in the conversion of radial to tranverse routes, designed for public transport in the city of Medellin. To obtain the existing noise pollution level and its subsequent comparison with the level from proposed redesign, a road map in the center of the city through the SoundPLAN software was carried out and various scenarios were predicted based on the analysis of decrease in the number of heavy vehicles in conflicting ways. Finally, air quality parameters, demand of passenger, travel time, and average speed were integrated in order to propose environmentally optimal routes and to improve mobility in the city.
Application of resonant acoustic spectroscopy to beam shaped asphalt concrete samples.
Authors: Gudmarsson Anders , Ryden Nils , Birgisson Björn
Published: October 2010

The dynamic modulus of asphalt concrete is a key parameter needed in modern pavement design and management. Traditional laboratory tests based on cyclic loading (0.1–25 Hz) at different testing temperatures are time consuming and require expensive equipment. There is therefore a need for more efficient non-destructive methods to determine the dynamic modulus of asphalt concrete. This study applies resonant acoustic spectroscopy (RAS) to beam shaped asphalt concrete samples. Multiple modes of vibration are measured at each testing temperature using a miniature accelerometer and a small steel sphere as impact source. The complex modulus from each resonant frequency is calculated using the Rayleigh–Ritz method. The heterogeneous and viscoelastic nature of asphalt concrete presents challenges to the application of conventional RAS. The number of measurable modes decreases with increasing test temperature. In an attempt to extend the usable frequency and temperature range measured, transfer functions are inverted using the finite element method along with a frequency dependent complex modulus. Initial results indicate that RAS can be an efficient method for the prediction of the high-frequency part of the asphalt concrete dynamic modulus mastercurve.
Single- and dual-channel rate discrimination by cochlear implant listeners.
Authors: Ihlefeld Antje , Carlyon Robert P.
Published: October 2010

Experiment 1 measured single-electrode rate-discrimination for two different electrodes (4 and 8) as a function of modulation depth. Stimuli were sinusoidally amplitude modulated, 200-ms monopolar biphasic pulse trains with a 5000-pps carrier rate, and an envelope frequency standard of 100 Hz, presented in a 2I-2AFC paradigm. Four cochlear implant listeners (CILs), users of MedEL Pulsar processors, participated. Performance generally improved with increasing modulation depth and was better on electrode 4 than on electrode 8. Using pairs of modulation depths with similar single-electrode performances, experiment 2 examined the combination of rate information across these two electrodes, when both electrodes were stimulated simultaneously with sinusoidal amplitude modulated pulse trains whose envelopes were either in phase or out of phase across electrodes. CILs-1 and -2 performed worse in the out-of-phase condition than in the in-phase condition. CIL-3 performed better in the out-of-phase condition than in the in-phase condition. CIL-4 showed no difference. Although performance was sometimes better with dual-channel than with single-channel stimulation, re-sults do not reveal a substantial and consistent benefit from combining information across electrodes. However, when modulation is applied to more than one electrode, results show that the phase relationship of envelopes across electrodes can affect a CIL’s ability to process modulation rate.
A comparison of three models for the principal pitch of vibrato tones.
Authors: Etchemendy Pablo , Mesz Bruno A. , Eguia Manuel C.
Published: October 2010

Vibrato is the more ubiquitous manifestation of a non-stationary tone that can evoke a single overall pitch, called principal pitch. Some recent results using non-symmetrical vibrato tones suggest that the perceived pitch could be governed by some stability-sensitive mechanism. A recently proposed one-parameter model based on time-frequency reassignment was able to predict previously reported results. [B. Mesz and M. C. Eguia, Ann. N.Y. Acad. Sci. 1169, 126–130 (2009)]. The proposed model has some biological plausibility since the local computations at each auditory channel needed for pitch estimation are based on phase information, so they could be implemented in principle using the time interval between action potentials in the auditory nerve fibers. In order to test this new model against two previously formulated models of vibrato pitch [H. Gockel et al., J. Acoust. Soc. Am. 109, 701–712 (2001)] and pitch saliency [Cariani. Proc. VIII Intl. Conf. Music Perception & Cognition, Evanston, IL (2004)], a psychophysical experiment using vibratos with fast and irregular frequency modulation, which yield quite different pitch predictions in the three models, is performed.
Localizing amplitude-modulated high-frequency tones in free field: Physical.
Authors: Hartmann William M. , Rakerd Brad , Macaulay Eric J.
Published: October 2010

Headphone experiments since the 1950s have shown that high-frequency tones can be lateralized if they are given low-frequency amplitude modulation (AM). Lateralization is mediated by the interaural time difference (ITD) of the amplitude envelope, and it resembles lateralization for a comparison sine tone having the frequency of the modulation in the AM tone. However, lateralization is distinct from localization because there are significant physical differences between the idealized AM signals in the headphone experiments and the signals arriving at a listener’s ears in free-field presentation. In free field, (1) the modulation percentage becomes different for the two ears, (2) a purely amplitude-modulated source inevitably acquires some frequency modulated component, (3) signals are sometimes overmodulated in one or both ears. Also, the ITD of the AM envelope is generally less than the ITD in the comparison low-frequency sine tone because the envelope ITD depends on the group delay, not the (larger) phase delay. Nevertheless, it is known that listeners can use the envelope ITD to localize high-frequency AM tones presented in free field. [E. J. Macaulay et al., J. Acoust. Soc. Am. 127, 1440–1449 (2010).] [Work supported by the NIDCD, Grant DC 00181.]
A listening test method to evaluate the dissimilarity of large sets of stimuli: Application to loudspeakers.
Authors: Michaud Pierre-Yohan , Meunier Sabine , Herzog Philippe , Lavandier Mathieu , Drouet d’Aubigny Gérard
Published: October 2010

The paired comparison method is usually recommended as the standard method to collect judgments of dissimilarity between audio stimuli. However, this method is only appropriate for similarity ratings involving a small number of stimuli, because the number of pairs to be tested in the experiment rapidly increases with the number of stimuli, thereby leading to very demanding tests. A method adapted from a visual perception study will be presented, which allows one to deal with large sets of stimuli. For each trial, the task consists in selecting one stimulus among three as the most similar to a reference stimulus. Simulations of “perfect” listeners’ judgments have been conducted to estimate the influence on the results of the numbers of stimuli and listeners. These simulations investigated the potential artifacts related to the proposed protocol. Listening tests have been conducted to evaluate the timbre restitution by 12 loudspeakers with the proposed method, for comparison with the results of Lavandier et al. (2008) involving paired comparisons. Both methods provided correlated dissimilarity data, and their MDS analysis yield to similar 2-D spaces. The proposed method allowed us to evaluate 37 loudpseakers. The MDS analysis provided a 3-D space including two dimensions common to the first panel.
Efficient coding of attenuated correlation among complex acoustic dimensions.
Authors: Stilp Christian E. , Rogers Timothy T. , Kluender Keith R.
Published: October 2010

If sensorineural systems are efficient, redundancy should be extracted to optimize information processing. Stilp et al. reported efficient coding of a robust correlation (r2 = 0.95) among complex acoustic attributes following passive exposure [J. Acoust. Soc. Am. 124, 2493 (2008)] and through continuous active testing [J. Acoust. Soc. Am. 126, 2203–2204 (2009)]. Across studies, discrimination of differences between sounds orthogonal to the correlation is initially poor relative to sounds consistent with the correlation. Only following continued testing, listeners discovered variance inconsistent with the correlation, and discrimination of orthogonal sounds improved. Present studies examine how strong a correlation must be to create these perceptual changes. Listeners discriminated stimuli (AXB) for which the correlation between two complex independent dimensions, attack/decay (AD) and spectral shape (SS), varied. Poorer discrimination of differences that do not respect the correlation persists when the range over which AD/SS covary is truncated (r2 = 0.65), and when orthogonal sounds are modestly oversampled (r2 = 0.89). When correlations are decreased by extreme oversampling of orthogonal sounds (r2 = 0.69) or addition of orthogonal sounds with more extreme values (r2 = 0.69), effects diminish. Connectionist models employing principal components analysis consistently predict listener performance across experiments. [Work supported by NIDCD.]
Relationship between medial-olivocochlear reflex strength and masked thresholds.
Authors: Garinis Angela C. , Werner Lynne A. , Abdala Carolina
Published: October 2010

Otoacoustic emission amplitude is reduced by contralateral acoustic stimulation (CAS). This effect is produced by the medial-olivocochlear (MOC) reflex. Past studies have shown that the MOC reflex is related to listening in noise and selective attention. The present study examined the relationship between the MOC reflex and masked thresholds in 14 normally hearing adults. Detection thresholds were determined for a 1000-Hz, 300-ms tone presented simultaneously with a 300-ms masker. Three masking conditions in which energetic or informational masking predominate were investigated. DPOAEs were evoked from 500–4000 Hz with primary tones swept in frequency at 8 s/oct, using a fixed f2/f1 ratio of 1.22 at 65/55 dB sound pressure level. The MOC reflex and MOC-shift were measured at DPOAE fine structure maxima at 948 and 1091 Hz with and without CAS. An inverse fast-Fourier transform was performed to evaluate MOC effects on individual DPOAE components. Preliminary data analyzes showed MOC activity to be correlated with masked thresholds for both indices of medial efferent function. Most notably, higher masked thresholds for the random and broadband conditions were associated with a stronger MOC reflex for DPOAE maxima around 948 Hz. These results suggest that MOC activation plays a role in selective listening.
The use of the kurtosis metric in the evaluation of industrial noise exposures.
Authors: Hamernik Roger , Qiu Wei , Davis Robert
Published: October 2010

Data from a chinchilla model of noise-induced hearing loss will demonstrate the value of using the statistical metric, kurtosis, along with an energy metric to evaluate complex industrial noise environments for hearing conservation purposes. Complex noises are non-Gaussian noises consisting of a combination of Gaussian continuous noise and noise transients, either impacts or noise bursts. Chinchillas were exposed to an interrupted and intermittent 97-dB sound pressure level broadband, non-Gaussian noise for 8 h/day for 3 weeks. The experimental noises were designed to model an industrial exposure. Groups of animals with 8/group were exposed to 1 of 12 different complex noise environments having a fixed spectrum and energy but with different temporal structures achieved by varying the transient peak, interval, and duration histograms. Preliminary results show that (1) hearing and sensory cell loss increase with increasing kurtosis despite a fixed energy; (2) at a given value of kurtosis, hearing trauma is invariant with respect to changes in the temporal structure of the noise exposure. A metric such as the kurtosis may be a necessary adjunct to spectral energy in the evaluation of industrial noise exposures for the purposes of hearing conservation. [Research supported by NIOSH Grant R01 OH 002317.]
Using hyperarticulation to quantify interaction between discourse functions.
Authors: Freeman Valerie
Published: October 2010

Social factors are known to affect speech production, but in discourse and conversation analytic branches of sociolinguistics, quantitative measures are not as common as qualitative observations. This study uses acoustic measures of hyperarticulation to quantify the effects of two interacting discourse functions: new-information signaling and stance expression. For each of five speakers in an hour-long political talk show, content analysis was performed on all phrases repeated three or more times to separate neutral from stance-expressing tokens and new from given repetitions of those tokens. Word, syllable, and vowel duration were measured from spectrograms; formant (LPC) and pitch (autocorrelation) values were measured at onset, 20%, 50%, 80%, and offset of stressed vowels. Preliminary results from repeated measures analysis of variance suggest that stance is indeed a significant predictor of hyperarticulation which interacts with newness for at least some speakers. This work shows one way that acoustic measures can quantify the relative contributions of interacting discourse variables and their effects on speech variation. The findings also have implications for future work in speech recognition: physical measures of hyperarticulation could be combined with parsing for newness to identify stance expression in natural speech or produce it in synthesized speech.
Dissecting rate of speech: The effect of phrase final lengthening on articulation rate.
Authors: Kendall Tyler , Thomas Erik R.
Published: October 2010

Articulation rate in a Mexican American community in Texas is examined in order to determine which social, cognitive, and linguistic factors influence the rate of speech. This research represents one facet of a larger inquiry into variation in temporal patterns in American English. Recent work has demonstrated the strong effect of utterance length on articulation rate—the (pause-exclusive) measure of speech units, typically syllables, produced per unit of time—but utterance-internal factors have been less examined. Here, particular attention is paid to the extent to which articulation rate may be a function of phrase-final lengthening, i.e., is variation in articulation rate a spurious effect of variability in phrase-final lengthening? The analysis of finely time-aligned orthographic transcripts conducted here, coded for intonational and intermediate phrases, indicates that rates of speech for final feet are tightly correlated with rates for non-final feet. Hence variation in articulation rate is not an artifact of the final feet. Non-linguistic factors, such as speaker sex and age, are shown to differentiate articulation rates significantly, though individual variability is also substantial. Statistical models of utterance-level-based and within-utterance articulation rate measures are compared and implications for studies of speech rate are discussed.
Naturalistic social communication and speech development in monolingual and bilingual infants.
Authors: Ramirez-Esparza Nairan , Garcia-Sierra Adrian , Kuhl Patricia K.
Published: October 2010

This investigation explores how everyday social communication between parents and infants relates to speech development. This goal is accomplished by using the digital recorder LENA that monolingual (N=11) and Spanish-English bilingual (N=10) 14-month-old infants wore for 4 days. Infants’ sample files (i.e., 160, 30-s intervals per infant) were coded according to the social communication coding inventory, which includes categories such as “babbling” (e.g., canonical versus variegated babbling), “social interactions” (e.g., baby was with one other person or with a group of people), “how adults are talking” (e.g., “motherese” versus adult talk), and “activities” (e.g., adult is reading and/or teaching). The results showed that babbling relates to relevant social communication categories in both groups. For example, the percentage of time “motherese” is used relates positively to babbling, but adult directed speech relates negatively to babbling. Interestingly, the amount of time monolingual parents spend teaching and reading to their infants relates positively to variegated babbling, but the amount of time bilingual parents have the TV on relates negatively to variegated babbling. These findings shed some light about how natural everyday social communication influences speech development in monolingual and bilingual infants. [Work supported by an NSF grant to the UW LIFE Center.]
Feature timing and identification for different solid cylinder exposures revealed using reversible image filtering.
Authors: Eastland Grant C. , Marston Timothy M. , Marston Philip L.
Published: October 2010

Understanding scattering features of proud and partially exposed cylinders is relevant to the scattering by a variety of simple targets. In the present investigation, partial exposure was studied by lowering a solid aluminum cylinder through a flat free surface into a tank of water while monitoring the evolution of the scattering as a function of the amount of exposure. Interactions with the free surface simulate aspects of interactions with flat sediment. Unlike related prior work, however, the present investigation allows for the recording of bistatic scattering and reversible image filtering based on a form of synthetic aperture sonar (SAS). The source and receiver grazing angles are held fixed while the amount of exposure h of a right circular aluminum cylinder is varied. Short pulses are used to distinguish between different types of scattering contributions. The slope of the feature timing as a function of the exposure h, expressed by the derivative dt/dh where t is the measured time of the feature, depends on the feature type as well as the source and receiver grazing angles. Free surface interactions for features revealed by the slope dt/dh are consistent with feature identification using reversible SAS filtering. [Work supported by ONR.]
Time domain calculation of propagation interference fringes (striations).
Authors: Harrison Chris
Published: October 2010

The waveguide invariant, which manifests itself as interference fringes or striations in a plot of frequency versus source-receiver separation, is usually thought of as a modal phenomenon. This paper shows that this phenomenon can be explained very simply through the variation of the eigenray arrival times with range; in short, the variation of the multipath impulse response. It is possible to calculate the value of beta [= (df/dr) /(f/r)] for a number of sound speed profiles analytically and to see what beta depends on, why it switches from one value to another, how it depends on source-receiver depth, and so on. The findings will be confirmed by calculating striation patterns numerically, starting from eigenray travel times in arbitrary stratified environments. Most importantly, the approach throws some light on what can be deduced from beta alone and the likelihood and utility of striations in reverberation.
Active invariance structure in deep water towed array data.
Authors: Zurk Lisa M. , Michalopoulou Zoi-Heleni , Rouseff Dan
Published: October 2010

The concept of a waveguide invariant has been used extensively to explain and exploit the time-frequency structure present in passive lofargrams. Recently this concept has been extended to active sonar data and has been demonstrated experimentally for both target and bottom scattering returns obtained in shallow water channels. In this talk, characteristics of the active invariance structure observed with towed horizontal arrays operating in deep water channels are presented and discussed. A towed array offers an ideal array aperture to observe the active invariance structure because a single pulse received across the array can be processed to recover the invariance striations. This processing offers higher resolution than what would be obtained with multiple returns from a moving target when sampled across a single receiver. Furthermore, for larger apertures operating at higher frequencies, the ability to observe the invariance intensity structure may be affected by details of the beamforming. The framework for towed array invariance processing is presented theoretically and illustrated with data obtained from a towed array operating in a deep water environment. As expected, the values for the deep water invariant differ from shallow water in both magnitude and sign.
Counting reflections in measured acoustic impulse response functions.
Authors: O’Keefe John
Published: October 2010

A novel method of counting reflections and reflection density has been developed. The method is borrowed from non-linear studies of fractal systems where time delayed versions of a signal are plotted against each other. In this case, the sound pressure p(t) of an impulse response function is plotted against its time derivative, dp(t)/dt. Each resulting circle represents a reflection. The results are, in effect, a dynamic version of (a normally steady state) Lissajous figure. Measured reflection counts are much lower than would be expected from theoretical predictions, primarily in the hundreds rather than thousands. A new method for estimating the temporal border between discrete and diffuse reflections is also presented.
Humpback whale posture and song propagation in very shallow water.
Authors: Sousa-Lima R. S. , Cortopassi K. A. , Clark C. W.
Published: October 2010

Male humpback whale song is thought to mediate inter- and intra-sexual interactions and to have an important role in mating strategies. This behavior was investigated on the Abrolhos bank off Brazil. Males were recorded in three different postures: (1) underwater; (2) at the surface; and (3) tail-up (upside-down position with fluke out of the water). Matching sounds emitted just before and just after singers changed from tail-up to singing at the surface (T-S) and from underwater to singing at the surface (U-S) were used to determine if posture affects song propagation. rms amplitude values for each sound in third-octave bands and in two custom frequency bands (70–350 Hz and roughly 700–3500 Hz) were calculated. rms amplitude ratios (U/S and T/S) were compared to determine if the median amplitude ratio was different from zero. The differences between T-S and U-S median rms amplitude ratios were also compared to test if the tail-up posture had any additional advantages in transmission over singing underwater. The results show that males increase the acoustic area of their song by almost nine times singing underwater or in the tail-up posture and, for the lower frequency components of the song, the tail-up posture further increases sound transmission.
Localizing and identifying captive whistling bottlenose dolphins.
Authors: Lopez-Rivas Rebeca M. , Bazúa-Durán Carmen
Published: October 2010

In the present study, a combined video-acoustic method was used to determine the identity of the whistling dolphin in an aquarium in Mexico City, where two adult bottlenose dolphins were housed. The hyperbola method was used to localize the sound source, finding that a dolphin was located along the hyperbola for 72.9% of the 960 recorded whistles. However, due to dolphin behavior, the identity of the whistling dolphin could only be determined for 60.3% of the whistles. Sometimes, it was possible to use other cues to identify the whistling dolphin: It could be the animal located closest to the hydrophone that captured the whistle or that which performed a behavior named observation when whistling occurred. Therefore, 15.4% of the whistles were further ascribed to either dolphin to obtain an overall identification efficiency of 75.7%. This is the first study to report such a high rate of identified whistles to the free swimming dolphin that produced them. The very simple and inexpensive video-acoustic method developed can be applied in other aquaria. Nevertheless, its actual efficiency in other aquaria will depend on how often dolphins spend time next to each other and on the reverberation conditions of the pool.
The soundfield around an echolocating Atlantic bottlenose dolphin.
Authors: Au Whitlow W. L. , Moore Patrick , Branstetter Brian , Finneran James J.
Published: October 2010

The use of remote autonomous passive acoustic recorders (PARs) to determine the distribution of dolphins at given locations has become very popular. Some investigators are using echolocation clicks to gather information on the presence of dolphins and to identify species. However, in all of these cases, the PAR probably recorded mainly off-axis clicks, even some from behind the animals. Yet we have a very poor understanding of the beam pattern and the click waveform and spectrum from different azimuths around the animal’s body. The beam pattern completely around an echolocating dolphin was measured at 16 different but equally spaced angles in the horizontal plane using an 8-hydrophone array in sequence. Eight channels of data were digitized simultaneously at a sampling rate of 500 kHz. The resulting beam patterns in both planes showed a continuous drop off in sound pressure with azimuth around the animal and reached levels below −50 dB relative to the signal recorded on the beam axis. The signals began to break up into two components at angles greater than ±45 deg in the horizontal plane. The center frequency dropped off from its maximum at 0 deg in a non-uniform matter.
Alternatives to A-weighting: Psychoacoustic background.
Authors: Fastl Hugo
Published: October 2010

As early as 1926 the late Professor Barkhausen from Dresden proposed a procedure for measuring noise, based on features of the human hearing system, which was patented in 1927. He used the psychoacoustic method of loudness comparisons which eventually led to the phon scale. His groundbreaking proposal to use human sound perception for noise measurement still deserves the highest praise. For more than 50 years, A-weighting follows this concept by mimicking a psychoacoustic feature, i.e., equal loudness contours. Despite the conceptual advantage of A-weighting, through the years also severe drawbacks showed up. In comparison to human loudness perception, low-frequency components and, in particular, broadband sounds are underestimated. To achieve the same loudness of sounds with different bandwidths, level differences even larger than 15 dB(A) can be necessary. Also concepts based on physical magnitudes like equal energy can deviate substantially from human sound perception. For example, the equal energy concept can lead to rather unrealistic predictions of noise emissions: If a new aircraft produces 20 dB(A) lower level, according to the equal energy prediction, one single loud old aircraft could be replaced by as many as 100 new softer aircraft! In the presentation, examples are given an how to overcome many of the drawbacks and unrealistic predictions of A-weighting by using advanced psychoacoustically based metrics.
Acoustical indicators in addition to the A-weighted sound pressure level: Options and strategies.
Authors: Fiebig André
Published: October 2010

Environment noise assessment methods adequately reflecting the inescapable nature of environmental noise (and the inexorable increase of noise effects) have been examined extensively for several decades. From the increasing number of complaints, it is clear that noise is still one of the most exigent environmental problems. A-weighted sound pressure level indicators were typically determined for classifying environmental noise and predicting (un-)acceptable noise exposure. These indicators are well-established and deeply ingrained in noise policy. Unfortunately, the dB(A) does not always reflect the annoyance aspect of environmental noise. A few shortcomings were observed, for example, that sometimes with certain sources, source combinations, or sound properties the correlations are poor between the (A-weighted SPL) dose and the measured response (share of highly annoyed people). Supplements to the A-weighted SPL must be applied to consider these shortcomings and to improve the effectiveness of the respective indicator. It is very important to extend conventional indicators and metrics to overcome these difficulties in predicting human reactions to environmental noise. Consideration of further indicators besides the dB(A) for environmental noise assessment could be valuable. Acoustical metrics for environmental noise description and classification will be presented. Further metrics will be tested in case studies and discussed.
International Institute of Noise Control Engineering (I-INCE) Technical Study Group 9 Environmental noise metrics: Opportunities and issues as seen from a solution supplier.
Authors: Manvell Douglas , Song Wookeun , Scholz Matthias , Weir Jim
Published: October 2010

The I-INCE Technical Study Group 9 on Environmental Noise Metrics is an exciting development that can help move the science and quality of environmental noise assessment forward. As an experienced supplier of solutions both within environmental noise assessment and within sound quality evaluation, Brel & Kjær is uniquely positioned to provide input based on the combined experience from both areas. This paper will raise issues, concerns, and opportunities arising from this international research collaboration as seen from a solution supplier’s point of view. This includes a review of existing work in sound quality that could be reused for environmental noise assessment and for soundscaping, practical experiences on measurement setup, and the possibility to compare and combine environmental noise measurements and different forms of simulation for even more exciting assessments and environmental noise management. Possibilities and challenges will be outlined and aspects for possible work in the group identified.