bluuebunny/crossref_metadata_2025 huggingface dataset:
Aerodynamic characteristics of French consonants
Authors: Demolin Didier , Hassid Sergio , Soquet Alain
Published: September 2013

This paper reports some aerodynamic measurements made on French consonants with a group of ten speakers. Speakers were recorded while saying nonsense words in phrases such as papa, dis papa encore. The nonsense words in the study combined each of the French consonants with three vowels /i, a, u/ to from two syllables words with the first syllable being the same as the second. In addition to the audio signal, recordings were made of the oral airflow, the pressure of the air in the pharynx above the vocal folds and the pressure of the air in the trachea just below the vocal folds. The pharyngeal pressure was recorded via a catheter (i.d. 5 mm) passed through the nose so that its open end could be seen in the pharynx below the uvula. The subglottal pressure was recorded via a tracheal puncture between the first and the second rings of the trachea or between the cricoid cartilage and the first tracheal ring. Results compare subglottal presssure, pharyngeal pressure, and airflow values. Comparisons are made between values obtained with male and female subjects and various types of consonants (voiced versus voiceless at the same place of articulation, stops, fricatives, and nasals).
The battle for F0: Glottalization versus stress in Statimcets
Authors: Bird Sonya , Caldecott Marion
Published: September 2013

The conflicts that arise in speech production give us insight into the interaction between faithfulness to mental representations and articulatory and acoustic limitations on speech. This paper presents an example of a perceptually based conflict [Kochetov, LabPhon8 (to appear)] in Statimcets, a Salish language spoken in the Interior of British Columbia. In a pilot study on glottalized resonants in Statimcets, Bird [ICSNL 38 (2003)] found that the primary cue to glottalization was creaky voicing, and that glottalization was reduced in stressed syllables. This paper expands on the previous study, incorporating new acoustic data on stress, and a more detailed acoustic analysis of glottalization. It is shown that one of the cues to stress, raised fundamental frequency (F0), conflicts with the lowered F0 associated with creaky voicing. In Statimcets, this conflict is resolved by preserving the perceptual salience of stress cues at the expense of cues to glottalization. This results in loss of glottalization in stressed syllables. Acoustic data and analyses will be presented. [Research supported by SSHRC.]
A multifilter approach to acoustic echo cancellation
Authors: Usher John , Woszczyk Wieslaw , Cooperstock Jeremy
Published: September 2013

Hands-free teleconferencing is increasingly frequent today. An important design consideration for any such communication tool that uses high-quality audio is the return echo caused by the acoustic coupling between the loudspeakers and microphones at each end of the conference. An echo-suppression filter (ESF) reduces the level of this return echo, increasing speech intelligibility. A new ESF has been designed based on a block frequency domain adaptive filter using the well-known least-mean-square (LMS) criteria. There are two important coefficients in LMS adaptive filters which affect how an ESF adapts to changing acoustic conditions at each end of the conference, such as double-talk conditions and moving electroacoustic transducers. Previous approaches to similar ESFs have used either a single or double pair of these coefficients, whereas the new model typically uses ten. The performance of single, double, and multifilter architectures was compared. Performance was evaluated using both empirical measurements and subjective listening tests. Speech and music were used as the stimuli for a two-way teleconferencing experiment. The new filter performed better than the single- and two-filter ESF designs, especially in conferencing conditions with frequent double talk, and the new ESF can be optimized to suit different acoustic situations.
Experimental demonstration of accurate hurricane classification from local wind speed estimates obtained with underwater sound
Authors: Wilson Joshua D. , Makris Nicholas C.
Published: September 2013

In 1999 Hurricane Gert passed over an autonomous hydrophone in the North Atlantic yielding a clear recording of the underwater noise generated by the hurricane. By correlating the noise with meteorological data from reconnaissance aircraft and satellites, it is shown that underwater noise intensity in the 10–50-Hz band is proportional to local wind speed to the 3.3 power. Previous experiments have shown similar relationships at lower wind speeds in many different ocean environments [Crouch, J. Acoust. Soc. Am. 51, 1066–1072 (1972); Marrett and Chapman, IEEE J. Ocean. Eng. 15, 311–315 (1990); Chapman and Cornish, J. Acoust. Soc. Am. 93, 782–789 (1993)]. Given this empirical relationship, it is shown that acoustic intensity measurements can be used to accurately estimate wind speed to within a 5% error margin, and so can be used to accurately classify the destructive power of a hurricane. Hurricane Gert, for example, is found to be a class 2 hurricane with maximum wind speeds of at least 89 kts by this underwater acoustic approach, which is in accord with aircraft measurements. Potential advantages of this underwater acoustic approach are discussed as are their potential impact on hurricane forecasting and disaster planning.
Inferring fish school distributions from long range acoustic images: Main acoustic clutter experiment 2003
Authors: Symonds Deanelle T. , Ratilal Purnima , Makris Nicholas C. , Nero Redwood W.
Published: September 2013

Long range scattering from fish schools and bottom reverberation in the New Jersey Continental Shelf environment are modeled using a unified, range-dependent, bistatic scattering, and reverberation model based on the parabolic equation [Ratilal and Makris, J. Acoust. Soc. Am. 114, 2302 (2003)]. The fish swim bladder is approximated as an air-filled bubble, while the bottom reverberation from volume inhomogeneities is modeled using the Rayleigh–Born approximation. The broadband scattered field, in the frequency range from 390 to 440 Hz, is beamformed and spatially charted using two-way travel time. The model output is compared with scattered field levels from fish schools and background reverberation measured during the the Main Acoustic Clutter Experiment 2003 using a long range, bistatic sonar system. The fish school characteristics, such as size, distribution and density, are inputs to the model. These are obtained from measurements made by the fish finding sonar during the experiment. This calibrated model is then used to infer fish school distributions and densities in areas where fish finding sonar measurements are not available.
Broadband, lower-frequency acoustic projector design for AUV applications
Authors: Howarth Thomas R. , Benjamin Kim C. , Huang Dehua , Tressler James F. , Carney Walter
Published: September 2013

Autonomous underwater vehicles (AUVs) offer a difficult platform for mounting lower-frequency acoustic projectors. Researchers at various U.S. Navy laboratories have been coordinating their interests to address the concepts and reduction to practice of lower frequency and broader operating frequency bands transduction technologies. Recent efforts have resulted in the development of cymbal-based acoustic transmitting devices to operate over an extended frequency range of 1 to 25 kHz within a package that can be housed inside of a BlueFin AUV. This presentation will discuss the concepts, design, development, and integration of the cymbal-based modular panels and how they are being configured to meet these applications. In situ data, including in-water calibration of acoustic performance, will be provided. Discussions for ongoing work and future directions will conclude the presentation. [Work supported by the ONR.]
1-3 Piezocomposite transducers for AUV applications
Authors: Pazol Brian , Lannaman Ken , Doust Barry
Published: September 2013

Sonar systems on board AUVs present interesting challenges to the transducer designer because of their small size, low weight requirements, and limited available power. 1-3 piezocomposite transducers offer many performance characteristics which make them ideal for deployment in AUVs. Piezocomposite transducers are light weight, have broad bandwidth, have high efficiency, and can be conformed to fit the curvature of the vehicle. The broad bandwidths and low sidelobes made possible by piezocomposites result in sharper images with less distortion. The piezocomposite material is mechanically robust and can survive the rigors of normal operations as well as AUV deployment and retrieval. In addition, the conformal configuration substantially reduces hydrodynamic drag. As a conformal array, there is nothing to get knocked off during deployment and retrieval operations, or entangled with natural or man-made objects suspended in the water column. This contributes directly to improving the operational endurance of the AUV system, thereby enhancing overall system utility. MSI has produced and tested a variety of piezocomposite transducers for use in obstacle avoidance, mine hunting, and acoustic communications. An overview of piezocomposites and recent results of piezocomposite transducers will be presented.
A framework of concurrent navigation and seabottom targets detection using acoustic sensors on AUVs
Authors: Liu Te-Chih , Schmidt Henrik
Published: September 2013

The use of Autonomous Underwater Vehicles (AUVs) for Mine Counter Measures (MCMs) is an area of active recent research. The excellent mobility of AUVs allows for multi-aspect sonar view of the targets for improved detection, tracking, and classification. However, the uncertainty of the platforms and associated target localization degrade the detection ability by AUVs. Furthermore, the weak signals from buried targets is another severe problem making detection by a single measurement impossible. A new acoustic sensing framework is proposed for detection and tracking seabottom targets based on the track-before-detect (TBD) technique. In contrast to the traditional methods, TBD tracks possible targets before the detection is declared. There are several advantages by using this framework: (1) Compared to the traditional method of detection followed by tracking, higher detection probability is achieved for dim target detection due to the integrated detection metric of TBD. (2) Compared to the multiple hypothesis tracker (MHT) method, instead of searching a diverge hypotheses tree, TBD speeds up the searching and decreases the computational load, which makes onboard implementation feasible. (3) The stochastic models of uncertainties of targets and AUVs are based on the Bayesian framework, and thus, it is easy to apply various recursive estimators such as the Kalman filter or particle filter for tracking individual targets as well as the AUV platforms. Results of a successful application of this method in the GOATS2002 experiment are demonstrated. [Work supported by ONR and NATO Undersea Research Centre.]
The effect of rail sources on noise-sensitive construction in Chicago
Authors: Homans Brian L.
Published: September 2013

Because of Chicago’s dominance as a rail center in the 19th and 20th centuries and the miles of track present, parcels of land available for residential and other noise-sensitive construction frequently lie adjacent to freight, commuter, and Chicago Transit Authority (CTA) tracks. As A-weighted sound levels commonly exceed 105 dBA underneath CTA elevated tracks, special methods of noise abatement for high-rise and other construction to address high noise levels are necessary. Also discussed will be methods of establishing acoustical criteria appropriate for commercial and residential interior spaces.
Acoustic pulse propagation through stable atmospheric boundary layer: Theory and experiment
Authors: Chunchuzov Igor , Kulichkov Sergey , Otrezov Alexander , Perepelkin Vitaly
Published: September 2013

Mesoscale wind speed and temperature fluctuations with periods from 1 min to a few hours significantly affect a variability and turbulent regime of stable atmospheric boundary layer (ABL). Their statistical characteristics are still poorly understood, although the knowledge of such statistics is required when modeling sound propagation through stable ABL. Several field experiments have been conducted to study the influence of mesoscale wind speed fluctuations on acoustic pulse propagation in stable ABL. The results of these experiments are presented in this work. A special acoustic source was used to generate acoustic pulses due to a detonation of air-propane mixture with a repetition period of 1 min or 30 s. The mean wind speed profiles and mesoscale wind fluctuations were measured by Doppler sodar up to a height of 300 m, and by anemometers placed on a 56-mast. From the measurements of the pulse travel time fluctuations at different distances from the source the statistical characteristics of the mesoscale wind fluctuations such as frequency spectra, coherences, horizontal phase speeds and scales have been obtained. Some of the obtained results are interpreted with a recently developed model of internal wave spectrum in a stably stratified atmosphere.
Doublet mechanics in acoustics
Authors: Layman Christopher N. , Wu Junru
Published: September 2013

Doublet mechanics (DM) presents a micromechanical approach to materials, whose properties allow for a granular characterization. In DM a pair (doublet) of interacting granules represents the fundamental unit of the material; these two granules are either in contact or connected via a thin adhesive layer. The actions of a doublet are described via a convergent Taylor series, which can be truncated at any level dependent upon how discrete the system is. This is the flexibility of DM, meaning it allows for the use of a single framework to describe materials from low discreteness (i.e., animal tissue) to high discreteness (i.e., solids). Some preliminary work [J. Liu and M. Ferrari, Dis. Markers 18, 175–183 (2002); J. Wu, C. Layman, and J. Liu, J. Acoust. Soc. Am. (in press)] has produced encouraging results in the application of DM to the ultrasonic characterization of tissue.
Computation of the dynamic thermal properties of a three-dimensional unit cell of porous media by Brownian motion simulation
Authors: Perrot Camille , Olny Xavier , Panneton Raymond , Bouchard Richard
Published: September 2013

Acoustic dissipation in porous media is mainly due to viscous and thermal mechanisms that occur in the pores of the microstructure. The purpose of this study is the determination of the macroscopic dynamic acoustic bulk modulus and thermal permeability of real foams from a local scale approach. To achieve this goal, two distinct steps are followed. First, the local geometry of a real foam is obtained using computed microtomography (μCT), then a periodic and regularly paving space tetrakaidecahedron cell is identified from the microstructure. Second, the heat equation is solved for the geometrical model. The paper provides a three-dimensional application of the efficient simulation technique of Brownian motion proposed by Torquato et al. for steady state diffusion-controlled problems [Appl. Phys. Lett. 55, 1847–1849 (1989)] and adapted by Lafarge [Poromechanics II, 708 (2002)] in a bi-dimensional case. The influence of the model’s microstructural details (anisotropy, and struts junction and cross-section) on the macroscopic properties are studied. The predictions of the macroscopic properties using this local scale approach are then compared to experimental measurements.
Diffusion of high-frequency energy in fluid-saturated porous media
Authors: Savin Eric
Published: September 2013

The modern mathematical theory of microlocal analysis shows that the energy associated with the high-frequency solutions of hyperbolic partial differential equations (such as the wave or the Navier equations) satisfy Liouville-type transport equations, or radiative transfer equations for randomly heterogeneous media. For long propagation times the latter can be approached by diffusion equations. Some classical results of the structural acoustics literature about the heat conduction analogy and the statistical energy analysis of structural dynamics at higher frequencies are recovered in this process. The purpose of this communication is to focus on such a diffusive regime for isotropic, fluid-saturated porous media. More specifically, we have derived the diffusion parameters (transport mean-free path and diffusion constant) for such media. Our model considers Biot’s equations of poroelasticity, where thermal and viscous effects are modelized by dynamic tortuosity and compressibility with singular memory kernels. The macroscopic bulk modulus and density of the dry solid phase are assumed to be homogeneous random processes, while tortuosity and porosity remain constant.
Omnidirectional elastic bandgap in finite one-dimensional phononic systems
Authors: Manzanares-Martínez Betsabe , Sánchez-Dehesa José , Håkansson Andreas , Cervera Francisco , Ramos-Mendieta Felipe
Published: September 2013

We have demonstrated experimentally the occurrence of omnidirectional elastic bandgaps in layered periodic structures. To date, omnidirectional reflection is a well-known phenomenon for the case of electromagnetic waves in photonic crystals [Y. Fink et al., Science 282, 1679 (1998)]. Theoretically a similar behavior of the elastic waves in phononic systems is predictable [D. Bria and B. Djafari-Rouhani, Phys. Rev. E 66, 056609 (2002)]. For the experiment we used finite samples of alternating layers of Pb and epoxy. The binding medium is nylon, which is a material of high elastic velocity, a favorable condition to find the effect. The thicknesses of the layers were chosen in order to have omnidirectional gap at a few hundreds of kHz. We found good agreement between the experimental results and the theoretical treatment of the transmittance through finite samples and the phononic band structure. The effect is shown only for longitudinal impinging waves. [Work supported by CICyT of Spain and CONACyT of Mexico.]
Acoustical study of the development of stop consonants in children
Authors: Imbrie Annika K.
Published: September 2013

This study focuses on the acoustic patterns of stop consonants and adjacent vowels as they develop in young children (ages 2.6–3.3) over a 6-month period. The acoustic properties that are being measured for stop consonants include spectra of bursts, frication noise and aspiration noise, and formant movements. Additionally, acoustic landmarks are labeled for measurements of durations of events determined by these landmarks. These acoustic measurements are being interpreted in terms of the supraglottal, laryngeal, and respiratory actions that give rise to them. Preliminary data show that some details of the child’s gestures are still far from achieving the adult pattern. The burst of frication noise at the release tends to be shorter than adult values, and often consists of multiple bursts, possibly due to greater compliance of the active articulator. From the burst spectrum, the place of articulation appears to be normal. Finally, coordination of closure of the glottis and release of the primary articulator is still quite variable, as is apparent from a large standard deviation in VOT. Analysis of longitudinal data on young children will result in better models of the development of motor speech production. [Work supported by NIH Grants DC00038 and DC00075.]
A developmental acoustic characterization of English diphthongs
Authors: Lee Sungbok , Narayanan Shrikanth , Byrd Dani
Published: September 2013

Acoustic properties of diphthongs in American English in a /bV/ context were investigated as a function of the age of child speakers (5–18 years, 450 subjects). Duration and the average amount of spectral change per frame were computed as a measure of the contrast between initial and final steady states, and the center position of the spectral transition (normalized for vowel length) was estimated as a measure of timing between the two steady-state portions. Results indicate that duration and temporal variability are significantly larger for children below age 10. The spectral change per frame was larger for younger children, suggesting more spectral contrast between diphthong steady states. Interestingly, the normalized center position of the glide occurs at a position relatively closer to the final portion of diphthongs for /ay/ for younger children; an opposite tendency was observed in the case of /ow/, implying that younger children exhibit delayed or premature spectral transitions. Together these observations suggest the possibility that 5–8-year olds may not produce diphthongs as a unit but, rather, as a concatenation of two vowel targets in which one component is more prolonged than the other and abrupt transitions occur. [Work supported by SBC/TRI, NSF, and NIH.]
Phonotactic constraints, frequency, and legality in English onset-cluster perception
Authors: Moreton Elliott
Published: September 2013

Phonological context can affect phoneme identification, favoring one response over another [Massaro and Cohen, Percept. Psychophys. 34, 338–348 (1983)]. It is unclear what is disfavored: infrequency, legality, or phonotactic constraint violation. This study compared bias on an [l]–[w] continuum in two situations. In one, the three factors were deliberately confounded; in the other, frequency and legality were controlled. Stimuli were synthetic syllables ambiguous between [blae bwae dlae dwae] (‘‘bd array’’) or [mlae mwae nlae nwae] (‘‘mn array’’). In the bd array, [bl dw] are legal, frequent English onsets, while [dl bw] have zero frequency, are illegal, and violate a constraint against same-place onsets; hence, ‘‘d’’ responses should facilitate ‘‘w’’ responses. The whole mn array is unattested and illegal, but [nl mw] violate the constraint. Simultaneous stop-sonorant judgments were obtained from English listeners for each 6-by-6 array. A mixed-effects logistic-regression model (including a term to model out compensation for coarticulation) was used to measure dependency between stop and sonorant responses. The bd array drew the expected bias against ‘‘dl.’’ Bias against ‘‘nl’’ in the mn array was considerably smaller, but still present. These results suggest that perceptual bias is jointly determined by constraint violation, and by frequency and/or legality.
Effect of retroflex sounds on the recognition of Hindi stops
Authors: Dev Amita , Agrawal S. S. , Choudhary D. Roy
Published: September 2013

As development of the speech recognition system entirely depends upon the spoken language used for its development and the very fact that speech technology is highly language dependent and reverse engineering is not possible, there is an utmost need to develop such systems for Indian languages. In this paper we present the implementation of a time-delay neural network system (TDNN) in a modular fashion by exploiting the hidden structure of previously phonetic subcategory network for the recognition of Hindi consonants. For the present study we have selected all the Hindi phonemes for the recognition. A vocabulary of 207 Hindi words was designed for the task-specific environment and used as a database. For the recognition of phonemes a three-layered network was constructed and the network was trained using the backpropagation learning algorithm. Experiments were conducted to categorize the Hindi voiced and unvoiced stops, semivowels, vowels, nasals, and fricatives. A close observation of the confusion matrix of Hindi stops revealed maximum confusion of retroflex stops with their nonretroflex counterparts.
A novel acoustic way of demarcating diphthong elements in Thai
Authors: Roengpitya Rungpat
Published: September 2013

Thai has three phonemic (falling) diphthongs /ia/, /i‘a/, and /ua/ and a set of the so-called rising diphthongs in Thai /ai/ /aj/ and /au/ /aw/. In previous (nonacoustic) literature, falling diphthongs are short when followed by a glottal stop. However, recent acoustic studies revealed that falling diphthongs in Thai are short in closed syllables, but long in open syllables. In the same literature, each diphthong was measured for the durations of its first vocalic element, the transition, and the second vocalic element, without demarcating the offset of the first vocalic element and the onset of the second vocalic element. This paper has the major aim of applying a new technique for making a plausible way to mark where the first vocalic element ends and the second vocalic element starts, not only for the set of falling diphthongs but also for the so-called rising diphthongs. Moreover, this new technique would help to find out whether the rising diphthongs in Thai have the combinations of two-vowel qualities or a vowel and a glide. It is hoped that this new method will be useful for the future acoustic studies in other languages of the world. [Work supported by new-lecturer grants, Chulalongkorn University.]
Formants and musical harmonics matching in Brazilian lied
Authors: Raposo de Medeiros Beatriz
Published: September 2013

This paper reports a comparison of the formant patterns of speech and singing. Measurements of the first three formants were made on the stable portion of the vowels. The main finding of the study is an acoustic effect that can be described as the matching of the vowel formants to the harmonics of the sung note (A flat, 420 Hz). For example, for the vowel [a], F1 generally matched with the second harmonic (840 Hz) and F2 with the third harmonic. This finding is complementary to that of Sundberg (1977) according to which the higher the fundamental frequency of the musical note, e.g., 700 Hz, the more the mandible is lowered causing the elevation of the first formant of the sung vowel. As Sundberg himself named this phenomenon, there is a matching between the first formant and the phonation frequency, causing an increase in the sound energy. The present study establishes that the matching affects not only F1 but also F2 and F3. This finding will be discussed in connection with other manoeuvres (e.g., tongue movements) used by singers.
Gestural stability in vowels
Authors: Purnell Thomas
Published: September 2013

In accordance with proper perception of linguistic sound units, past research has demonstrated some degree of acoustic and physiological stability. In contrast, articulatory stability has been thought to be inconsistent because articulations may vary so long as the vocal tract area function results in appropriate formant structure [Atal et al., J. Acoust. Soc. Am. 63, 1535–1555 (1978)]. However, if the area function for the constriction and its anterior region can maintain acoustic stability, articulatory stability should be observed in the relational behavior of four tongue pellets used in xray microbeam data. Previous work examined normalized pellet data in order to arrive at an average posture for each vowel [Hashi et al., J. Acoust. Soc. Am. 104, 2426–2437 (1998)]. But by assuming static (average) gestures, the research fell short of a correct postural characterization. This study of tongue pellet speed and normalized pellet displacement of front vowels spoken by ten microbeam database subjects reports that the tongue tip pellet speed maxima identify vowel edges (end of vowel onset, beginning of offset) while displacement of the three anterior pellets identify changes in formant structure (e.g., two stable regions in the Northern Cities English front low vowel).
Some effects of prosodic structure on the production of /u/ in French
Authors: Tabain Marija , Perrier Pascal , Savariaux Christophe
Published: September 2013

In this paper we present formant data and EMA (Carstens) data from two female speakers of French who produced /u/ in domain-final position at four different prosodic boundaries (in hierarchical order: utterance, intonational phrase, accentual phrase, and word boundaries). The prosodic boundaries are used in order to control the acoustic duration of the /u/, with greatest duration at the strongest boundary (utterance) and shortest duration at the weakest boundary (word). We present results on lip protrusion and tongue body targets with respect to these prosodically induced differences in duration, and compare these articulatory results with measurements of F1 and F2−F0 in Bark. We examine trade-offs between lip and tongue targets as duration is reduced, and speculate as to whether the speakers may have been aiming for an articulatory target or an acoustic target for /u/ at the stronger prosodic boundaries. This work combines our previous work on articulatory prosody of /a/ [Tabain, J. Acoust. Soc. Am. 113, 516–531 (2003)] with our previous work on perturbation of /u/ [Savariaux et al., J. Acoust. Soc. Am. 98, 2428–2442 (1995)]. [Work supported by an Australian Research Council fellowship to the first author.]
Probability density functions for hyperbolic and isodiachronic locations
Authors: Spiesberger John L. , Wahlberg Magnus
Published: September 2013

Animal locations are sometimes estimated with hyperbolic techniques by estimating the difference in distances of their sounds between pairs of receivers. Each pair specifies the animal’s location to a hyperboloid because the speed of sound is assumed to be spatially homogeneous. Sufficient numbers of intersecting hyperboloids specify the location. A non-linear method is developed for computing probability density functions for location. The method incorporates a priori probability density functions for the receiver locations, the speed of sound, winds, and the errors in the differences in travel time. The traditional linear approximation method overestimates bounds for probability density functions by one or two orders of magnitude compared with the more accurate non-linear method. The non-linear method incorporates a generalization of hyperbolic methods because the average speed of sound is allowed to vary between different receivers and the source. The resulting ‘‘isodiachronic’’ surface is the locus of points on which the difference in travel time is constant. Isodiachronic locations yield correct location errors in situations where hyperbolic methods yield incorrect results, particularly when the speed of propagation varies significantly between a source and different receivers.
Listening to distant earthquakes with hydrophones on autonomous oceanic floats
Authors: Simons Frederik , Nolet Guust , Babcock Jeff
Published: September 2013

We are mounting a hydrophone on autonomous floats capable of drifting below the sound channel and surfacing to communicate data by a satellite link. Using new, intelligent algorithms for the automatic identification and discrimination of seismic phases, we recognize teleseismic arrivals in the presence of local P, S, and T phases, ship and whale noise, and other contaminating factors such as airgun surveys. Our approach combines time-domain methods with spectrogram analysis and with wavelet methods. To maximize battery life, we optimize the efficiency of our algorithms and their numerical implementation. Our algorithms were tested on data from tethered hydrophones from two arrays anchored to the Mid-Atlantic Ridge and the East Pacific Rise. Our prototype device was succesfully tested in a dive to 700 m off the coast of La Jolla. We acquired a valuable 31-h data stream suitable to characterize the ambient noise and were able to identify a number of engineering problems with the hydrophone sensitivity. We expect detecting teleseisms with magnitudes superior to 6.3, and thus adding at least 200 high-quality recordings to the global catalog over the life span of a single instrument—well worth the $15000 manufacturing price and negligible deployment costs on ships of opportunity.
Noise annoyance caused by magnetic levitation train passbys
Authors: Vos Joos
Published: September 2013

In a laboratory study, the annoyance caused by the passby sounds from a magnetic levitation (maglev) train was investigated. The outdoor A-weighted sound exposure level (ASEL) of the maglev sounds varied from 65 to 90 dB. The driving speed of the maglev train varied from 100 to 400 km/h. Four important results were obtained. Provided that the outdoor ASELs were the same, (1) the annoyance was independent of the driving speed of the maglev train, (2) the annoyance caused by the maglev train was considerably higher than that caused by intercity trains, (3) the annoyance caused by the maglev train was hardly different from that caused by road traffic (passenger cars and trucks), and (4) the results (1)–(3) held true both for open or closed windows. On the basis of the present results, it might be expected that the sounds are equally annoying if the ASELs of the maglev-train passbys are at least 5 dB lower than those of the intercity train passbys. Consequently, the results of the present experiment do not support application of a railway bonus to the maglev-train sounds. Issues for future research, such as exploring further contributions of nonacoustic factors, will be discussed.
Nonsensory factors in speech perception
Authors: Holt Rachael F. , Carney Arlene E.
Published: September 2013

The nature of developmental differences was examined in a speech discrimination task, the change/no-change procedure, in which a varying number of speech stimuli are presented during a trial. Standard stimuli are followed by comparison stimuli that are identical to or acoustically different from the standard. Fourteen adults and 30 4- and 5-year-old children were tested with three speech contrast pairs at a variety of signal-to-noise ratios using various numbers of standard and comparison stimulus presentations. Adult speech discrimination performance followed the predictions of the multiple looks hypothesis [N. F. Viemeister and G. H. Wakefield, J. Acoust. Soc. Am. 90, 858–865 (1991)]; there was an increase in d by a factor of 1.4 for a doubling in the number of standard and comparison stimulus presentations near d values of 1.0. For children, increasing the number of standard stimuli improved discrimination performance, whereas increasing the number of comparisons did not. The multiple looks hypothesis did not explain the children’s data. They are explained more parsimoniously by the developmental weighting shift [Nittrouer et al., J. Acoust. Soc. Am. 101, 2253–2266 (1993)], which proposes that children attend to different aspects of speech stimuli from adults. [Work supported by NIDCD and ASHF.]
Comments on ‘‘intimacy’’ and ITDG concepts in musical performing spaces
Authors: Beranek Leo L.
Published: September 2013

The word ‘‘intimacy’’ as related to the initial-time-delay gap (ITDG) measured in halls for musical performance was born in 1961. Of two concert spaces, one was successful acoustically and the other much less so. The halls had the same number of seats and reverberation times, the principal difference being their ITDG’s. To many, the hall with larger ITDG sounded arena-like and thus not ‘‘intimate.’’ The effect of differing ITDGs appears in three of the author’s books (Wiley, New York, 1962), (Acoustical Soc. of America, Melville, NY, 1996), and (Springer-Verlag, NY, 2003), with the conclusion that ITDG is an important parameter affecting the acoustical quality of concert halls and opera houses. The question is whether the word ‘‘intimacy,’’ used in an acoustical sense, should be synonymous with ITDG. Barron (Spon, London, 1993) defines, ‘‘Intimacy refers to the degree of identification between the listener and the performance, whether the listener feels acoustically involved or detached from the music.’’ He found from jury subjective judgments that there was little correlation between ITDG and the word ‘‘intimacy.’’ This paper presents the author’s present thinking on the usefulness of the word ‘‘intimacy’’ in acoustics of halls for music, and discusses experiences with the visual effect on ‘‘intimacy.’’
A cognitive approach to soundscape research
Authors: Dubois Daniele , Guastavino Catherine , Maffiolo Valerie , Raimbault Manon , Guastavino Catherine , Maffiolo Valerie , Raimbault Manon
Published: September 2013

The present research on cognitive categories for soundscapes focuses on their interpretations and can be seen as mediating between individual sensory experiences and collective representations shared in language and elaborated as knowledge. Results of field inquiries in Paris, Lyon, and Nantes are presented together with results from categorization of recorded soundscapes in laboratory conditions. Categories were identified by means of linguistic analyses of verbal comments and mathematical analyses of similarity judgments. Results indicate that people categorize environmental sounds on the basis of semantic features, namely source identity and pleasantness judgments, rather than perceptual features. Effects of noise on human subjectivity cannot be quantitatively measured thoroughly in terms of physical parameters: auditory judgments depend upon the meaning attributed to acoustic phenomena and noise sources, rather than on inherent properties of the acoustic signal. These findings highlight the fact that an acoustic phenomenon can be diversely conceptualized and lexicalized as cognitive representations. Finally, methodological and theoretical consequences of these findings are established as the basis for further research on soundscape, in order to account not only for noise annoyance but also for sound quality of urban life.
Miller and Nicely’s confusion data are predicted by Fletcher’s AI
Authors: Allen Jont B.
Published: September 2013

Starting from the confusion matrix data Pij(SNR) of Miller and Nicely, where i indexes the stimulus and j the response, the average performance intensity (PI) function, over the 16 consonants, may be defined as P̄(SNR)=∑i=116Pii(SNR). These data are for five female talkers. The average speech power for five female talkers is known from Dunn and White. Thus, the articulation index (AI) may be computed at each SNR value (the maximum AI value is 0.6). This allows one to re−express P̄(SNR) as P̄(AI). When the resulting function is compared to Fletcher′s formula for the AI, P(AI)=1-eminAI, with emin=0.015, the agreement is nearly perfect. Thus, the Miller and Nicely average phone data may be modeled by AI theory. This result seems astounding, as it falls outside normal realm of the AI, which was intended for a much larger mix of sounds, not 16 consonants and a fixed vowel. Most individual consonant PI functions obey the same Fletcher AI formula, but with different values of emin.
Vowel normalization for accent: An investigation of perceptual plasticity in young adults
Authors: Evans Bronwen G. , Iverson Paul
Published: September 2013

Previous work has emphasized the role of early experience in the ability to accurately perceive and produce foreign or foreign-accented speech. This study examines how listeners at a much later stage in language development—early adulthood—adapt to a non-native accent within the same language. A longitudinal study investigated whether listeners who had had no previous experience of living in multidialectal environments adapted their speech perception and production when attending university. Participants were tested before beginning university and then again 3 months later. An acoustic analysis of production was carried out and perceptual tests were used to investigate changes in word intelligibility and vowel categorization. Preliminary results suggest that listeners are able to adjust their phonetic representations and that these patterns of adjustment are linked to the changes in production that speakers typically make due to sociolinguistic factors when living in multidialectal environments.
Child directed speech, speech in noise and hyperarticulated speech in the Pacific Northwest
Authors: Wright Richard , Carmichael Lesley , Beckford Wassink Alicia , Galvin Lisa
Published: September 2013

Three types of exaggerated speech are thought to be systematic responses to accommodate the needs of the listener: child-directed speech (CDS), hyperspeech, and the Lombard response. CDS (e.g., Kuhl et al., 1997) occurs in interactions with young children and infants. Hyperspeech (Johnson et al., 1993) is a modification in response to listeners difficulties in recovering the intended message. The Lombard response (e.g., Lane et al., 1970) is a compensation for increased noise in the signal. While all three result from adaptations to accommodate the needs of the listener, and therefore should share some features, the triggering conditions are quite different, and therefore should exhibit differences in their phonetic outcomes. While CDS has been the subject of a variety of acoustic studies, it has never been studied in the broader context of the other ‘‘exaggerated’’ speech styles. A large crosslinguistic study was undertaken that compares speech produced under four conditions: spontaneous conversations, CDS aimed at 6–9-month-old infants, hyperarticulated speech, and speech in noise. This talk will present some findings for North American English as spoken in the Pacific Northwest. The measures include f0, vowel duration, F1 and F2 at vowel midpoint, and intensity.
A new microsystem for near whispering
Authors: Choi Sungjoon , Moon Wonkyu , Lee Jeong Hyun
Published: September 2013

A new microphone system was developed to monitor the human voice near the microphone in a noisy environment. The system is equipped with two special functions in addition to the usual microphone functions: reduction of air blow effects by the mouth and focused reception to a sound source. A wind filter was developed to reduce the air blow effects from the mouth during speaking. This filter is a plate perforated by an array of small holes; the method used to design the filter is also presented. To achieve focused reception, four microphones were used in conjunction with a new signal processing method. The proposed signal processing method effectively increases the directivity in the desired direction. Additionally, it provides the system with focusing on the source since the source is located adjacent to the system. A prototype of the proposed system was fabricated and subjected to performance tests. The results showed that air blow effects can be reduced by up to 20 dB and the directional gain is more than 4 dB. The proposed microphone system shows such good performance that it can be used in mobile phones for whispering communication.
Ultrasound parametric imaging of coral
Authors: Bossy Emmanuel , Cohen Anne , Cleveland Robin O.
Published: September 2013

The skeletal density of several massive reef coral species is strongly correlated with ocean temperature, and it has recently been proposed as a paleoclimate proxy offering access to multicentury-long records of sea surface temperature. The presence of annual growth bands (from a few mm up to 1 or 2 cm wide) provides a chronological tool that enables changes in skeletal density to be traced through time. In this work, we investigate the feasibility of imaging the coral skeletal density using ultrasound. As the structure of coral is very close to that of trabecular bone, techniques successfully applied to bone imaging were assessed on coral. Ultrasonic measurements in the MHz frequency range were carried out in the laboratory on machined coral samples, using backscattering and through-transmission configuration. Parametric images were generated from the derivation of ultrasonic parameters such as acoustic impedance, velocity, backscatter coefficient, and attenuation. As x-ray absorption is directly related to the density of the coral, x-ray images were obtained as reference images. Preliminary results show qualitative agreement between x-ray images and ultrasound parametric images, indicating the potential for ultrasound to image coral. [Work supported by NSF through the Centre for Subsurface Sensing and Imaging Systems, Award Number EEC-9986821.]
Faraday film patterns
Authors: Holt R. Glynn , Saylor John R.
Published: September 2013

Locally flat liquid interfaces that are periodically forced to vibrate above a threshold amplitude exhibit an instability to waves of finite amplitude and half the forcing frequency. These waves (first observed and explored by Faraday) self-organize into a variety of patterns depending on experimental parameters. We report here the use of Faraday waves in liquid/particulate mixtures to cause deposition of the suspended particles in patterns that mimic the overlaying Faraday wave field. In this work the liquid/particulate mixture is deposited on a solid substrate in the form of a thin film. Hence the wave motion has a significant effect on the velocity field near the solid surface affecting the deposition locations of the particles. Subsequent evaporation of the liquid phase results in a stable, patterned, particulate film. We demonstrate this method experimentally at millimeter scales using relatively large particles, and discuss the possibility of using this method at higher frequencies to create particulate patterns at the micrometer and nanometer scales. Simulations of gold/silver particulate mixtures reveal variations in the particulate deposition pattern for these two particle types due solely to their density difference, suggesting a possible method for generating composite materials tailored on a very fine scale.
Landmine detection using acoustic to seismic coupling: Theory and modeling
Authors: Waxler Roger , Velea Doru
Published: September 2013

It has been demonstrated that buried landmines can be found by insonifying the ground and then measuring the resulting vibration of the ground’s surface. Over a buried landmine there is a large enhancement of the ground’s vibration due to the excitation of mechanical modes of the mine. The resulting ground vibration can be understood as the near-field response to the resonant scattering of sound by the buried landmine. An effective fluid model has been developed. The results and limitations of this model will be discussed.
Influence of data uncertainty on matched-field geoacoustic inversion
Authors: Huang Chen-Fen , Gerstoft Peter , Hodgkiss William S.
Published: September 2013

Quantifying uncertainty in matched-field geoacoustic inversion using a Bayesian approach has attracted the attention of several authors in recent years. The complete solution to the inverse problem is given by the posterior probability distribution (PPD) in the model space given good knowledge of the noise statistics. Therefore, an estimate of noise (including measurement errors and model mismatch) is essential to obtain the PPDs. In this study, several approaches to accommodating the effects of the noise are suggested, such as using different likelihood functions or treating the noise as a nuisance parameter. The posterior probability of the model parameters is sampled using a Gibbs sampler approach based on the Metropolis algorithm. Comparisons between the approaches using synthetic data and experimental data are presented. [Work supported by ONR.]