bluuebunny/crossref_metadata_2025 huggingface dataset:
Spatial uncertainty reduces the benefit of spatial separation in selective and divided listening
Authors: Ihlefeld Antje , Sarwar Shawn J. , Shinn-Cunningham Barbara G.
Published: October 2013

Spatial separation between two talkers can improve speech intelligibility (i.e., cause spatial unmasking) when attending to either one talker (selective listening) or both talkers (divided listening). Such spatial unmasking occurs by (1) allowing listeners to hear otherwise inaudible portions of the signal(s) (energetic masking) and (2) reducing central competition between similar talkers (informational masking, IM). Here, we examine how a priori knowledge affects spatial unmasking in selective and divided listening in IM-dominated stimulus conditions. Performance was measured in blocks where the locations of the talkers were either constant (fixed) or varied from trial to trial (spatially randomized). Spatial separation improves performance in both selective and divided tasks when locations are fixed. In the fixed conditions, the acoustic signal-to-noise ratio at the better ear for the less-intense talker partially accounts for the spatial unmasking; however, there is also a large residual spatial unmasking, similar to that seen in previous studies. In the spatially randomized conditions, spatial unmasking is much reduced. In addition, in the divided listening, randomized conditions there is little evidence for any better-acoustic-ear effect. Results suggest that the way in which subjects utilize spatial cues depends on their knowledge of the source locations. [Work supported by ONR Grant No. N00014-04-1-0131.]
Nonaxisymmetric acoustic scattering from submerged prolate spheroidal shells
Authors: Boisvert Jeffrey E. , Hayek Sabih I.
Published: October 2013

The equations of motion for nonaxisymmetric vibration of prolate spheroidal shells of constant thickness were derived using Hamiltons principle [S. I. Hayek and J. E. Boisvert, J. Acoust. Soc. Am. 114, 2799–2811 (2003)]. The shell theory used in this derivation includes shear deformations and rotatory inertias. The shell displacements and rotations were expanded in infinite series of comparison functions. These include associated Legendre functions in terms of the prolate spheroidal angular coordinate and circular functions in the azimuthal angle coordinate. The shell is insonified by a plane wave with arbitrary incident angle. The external (heavy) fluid-loading impedance was computed using an eigenfunction expansion of prolate spheroidal wavefunctions. Far-field backscattered acoustic pressure spectra are presented as a function of incident angle for several shell thickness-to-half-length ratios ranging from .005 to 0.1, and for various shape parameters, a, ranging from an elongated spheroidal shell (a=1.01) to a spherical shell (a∼100). The far-field directivity of acoustic scattering is presented at selected frequencies and plane wave incident angles. [Work supported by the ONR/ASEE Summer Faculty Research Program and the NAVSEA Newport ILIR Program.]
Scattering of an obliquely incident plane wave from an immersed transversely isotropic rod covered by an isotropic cladding
Authors: Sodagar Sina , Honarvar Farhang , Sinclair Anthony N.
Published: October 2013

Valuable information is contained within the scattered pressure field from a submerged elastic cylinder. Many theoretical and experimental investigations on the scattering from elastic cylinders have been carried out during the past few years. This includes recent work of the authors on modeling of the scattered pressure field from immersed transversely isotropic cylinders and immersed isotropic clad rods. In the current paper, an analytical solution to the problem of acoustic wave scattering from an immersed transversely isotropic cylinder covered by an isotropic cladding is presented. The mathematical expressions are derived for the far-field backscattered amplitude spectrum, normal modes, frequency spectrum, and phase diagrams resulting from oblique insonification of an infinite, transversely isotropic cylinder covered by an isotropic cladding. The validity of the mathematical model is verified by comparing the results with data available in the literature for simpler cases, such as transversely isotropic rods and isotropic clad rods. The results are also consistent with elasticity theory.
Active control of vibration of fluid-loaded plates at moderately large amplitudes
Authors: Vendhan Chiruvai P. , Suryanarayana Prasad A. N.
Published: October 2013

The problem of active control of vibrations has been studied by many in recent years. Gu and Fuller [J. Acoust. Soc. Am. 93, 337–345 (1993)] considered the linear vibrations of a simply supported rectangular plate in a fluid half-space following the analysis of Sandman [J. Acoust. Soc. Am. 61, 1502–1510 (1977)] and studied active control strategies to minimize the far-field sound-pressure levels. They evaluated the fluid loading using the classical solution for a baffled point source. Following a similar approach, Prasad et al. [Prasad et al., J. Acoust. Soc. Ind. 33, 535–540 (2005)] developed a Rayleigh-Ritz analysis capability for the linear vibration of fluid-loaded rectangular plates with a variety of boundary conditions. The present article is concerned with the nonlinear vibration of a simply supported isotropic square plate. The Duffing-type modal equation based on a single transverse mode approximation [AIAA J. 13, 1092–1094 (1975)] has been chosen. The fluid loading is calculated using the procedure mentioned above. The equivalent linearization technique has been employed to reduce the nonlinear equation and solution in the form of frequency response function (FRF) obtained using an iterative procedure. The effect of piezoelectric patches mounted at the center of the plate is studied.
Study on the acoustic similitude of the underwater complex shell structure
Authors: Wang Sande
Published: October 2013

The underwater noise that is produced by the underwater complex shell structure is a basic question to be solved for the noise control of an underwater structure. One way to study and control the underwater noise of the underwater complex shell structure is the experiment of vibration and sound radiation of all kinds of scaled-down models for its prototype. This method can predict vibration and sound radiation of an underwater complex shell structure, and provides the necessary parameters for the design of noise control. Using the finite-element method and the spherical function spread method, this paper investigates the similitude of coupled vibration and acoustic radiation for the typical structure of an underwater vehicle (elastic ring-stiffened cylindrical shell with hemispherical caps on the ends), and presents acoustic similitude conditions and relationships of the structures. At the same time, the acoustic scale effect and boundary effect, which are influenced by loss factors, shear and rotatory inertia, and surface sound reflection are investigated in detail. The results show that these effects can be controlled with similitude model designing and experiment design.
High-frequency broadband radiation from panels and periodic structures including the effect of structural power flow on directivity
Authors: Bliss Donald , Franzoni Linda , Danilov Pavel
Published: October 2013

In the high-frequency limit, a vibrating panel subject to spatially random temporally broadband forcing is shown to have broadband power and directivity properties that can be expressed analytically by a limited set of parameters. The radiated pressure-field power and directivity are characterized in terms of the structural power flow direction, wave-speed ratio, panel damping, and dimensionless frequency. The role of boundary conditions at the panel edge is illustrated, as are the effects of other types of forcing. Corresponding behaviors for panels coupled to form a periodic structure are also shown by approximate analytical solutions and numerical simulation. Overall, relatively simple broadband behaviors are revealed. For a single panel the analytical characterization is shown to be particularly straightforward in the high-frequency broadband limit. The relationship between radiation and structural power flow is potentially useful in energy-intensity-based prediction methods with application to aircraft interior noise prediction.
Rudimentary phrasal parsing in preverbal French-learning infants
Authors: Bouchard David-Etienne , Shi Rushen
Published: October 2013

The present study examines the initial parsing of noun phrases in infants. Participants were 8-month-old Quebec-French-learning infants. During Familiarization, infants heard two types of trials, one presenting a noun phrase sliced from a sentence (NP trial) and the other presenting the same word sequence (as in the NP trial) but sliced from another sentence in which these words were a part of a noun phrase and a part of a verb phrase, i.e., a non-unit trial. During Test, infants heard the original sentence containing the sliced NP and that containing the sliced non-unit. Two pairs of noun phrases and non-units were used in the experiment across two groups of infants. We predicted that if infants encoded the sliced stimuli in the NP trial as more coherent than those in the non-unit trial during Familiarization, they should listen longer to the sentences containing the NPs than those containing the same words but constituting non-units. Preliminary results show that infants listened significantly longer to the sentences containing the sliced noun phrases, even though the NP trial and non-unit trial during Familiarization involved exactly the same words. This finding suggests that salient prosodic markings enable French-learning infants to parse noun phrases from sentences.
Children’s production of prosody: Disambiguating sets of compound nouns
Authors: Yoshida Michiko , Katz William F.
Published: October 2013

Studies have suggested that although young children may perceive prosodic patterns marking structural boundaries in ambiguous sentences (e.g., distinguishing ‘‘pink and green, and white’’ from ‘‘pink, and green and white’’), children do not necessarily produce these prosodic patterns. However, most of these studies did not test perception and production in the same group of subjects. Therefore, the relation between perception and production for a given linguistic structure could not be clearly established. Yoshida and Katz [‘‘Children’s use of prosody to identify ambiguous sets of compound nouns,’’ J. Acoust. Soc. Am. 116, 2645 (2004)] had young children and adults listen to resynthesized speech versions of ‘‘sun/flower/pot.’’ F0 and duration patterns were parametrically manipulated to provide a continuum of interpretations between ‘‘sun, flowerpot’’ and ‘‘sunflower, pot.’’ Results indicated that children showed adultlike processing of duration and F0 cues. The current study reports acoustic data for productions made by these same subjects (elicited prior to the perceptual experiment). Subjects played a naming game with pictures that depicted either (a) a sunflower and a pot or (b) a sun and a flowerpot. Acoustic analyses support the idea that children and adults control both duration and F0 to disambiguate their utterances. Results suggest that previous studies may have underestimated young children’s capacity for producing prosodic structures.
Fricative development in English-learning children
Authors: Lowenstein Joanna H. , Nittrouer Susan
Published: October 2013

Acoustic studies of school-aged children’s fricatives have demonstrated that those gestures are not as precisely specified as in adult speech [e.g., S. Nittrouer, J. Acoust. Soc. Am. 97, 520–530 (1995)]. The current study examined the development of English fricatives at younger ages by audiotaping seven children at 2-month intervals from the onset of first words (around 14 months) to the onset of three-word sentences (around 30 months). Two measures were made: the numbers of words produced with intended /s/ and /sh/ in initial and final word positions were counted, and first through fourth spectral moments were derived for each /s/ and /sh/ noise at each recording session. Fricatives were rare until after 24 months of age. /s/ was produced earlier than /sh/, and /s/ was produced in word-final before word-initial position. The first moments of /s/ and /sh/ were similar, and both resembled those of /sh/ spectra produced by slightly older children. Spectral skewness and kurtosis were produced with the same degree of separation for /s/ and /sh/ as those of adults, but values were more negative. Results suggest that these children were starting to develop mature spectral shapes for /s/ and /sh/. [Work supported by NIDCD Grant No. DC-00633.]
Development of phrase boundary effects
Authors: Zepralka Sara , Kollia Betty
Published: October 2013

In this study we investigate the acquisition and development of phrase-final lengthening in children ages 3 to 7 years of age. Fifteen subjects participated in the study. Preliminary data indicate that subjects produced more adultlike phrase-final lengthening at younger ages, with phrase-final lengthening duration decreasing with increasing age. Statistically significant phrase-final lengthening was observed in 9 of the 15 subjects. Suggestions for this pattern of acquisition and future research are discussed.
Perceptual assimilation in context and isolation
Authors: Harnsberger James , Wayland Ratree , Silver Jenna
Published: October 2013

A study was conducted to examine the effects of sentence context and speaking rate in the perceptual assimilation of non-native speech sounds. Native speakers of American English were presented with two voicing contrasts, [k]-[g] and [t\/sh]-[d\/yog], produced by two Hindi speakers. They appeared word-initially before [a] and within a short sentence frame. These sentences were produced at three speaking rates (slow, normal, and fast). Listeners were administered a categorial AXB discrimination test and a forced-choice identification test. The results were compared to those collected in a previous study that employed the same contrasts appearing in isolated words and produced by the same talkers. The results showed that the discrimination of these speech sounds in a sentence frame was significantly poorer relative to the isolation context. Moreover, the modal native consonant used to classify the Hindi stops varied depending upon the sentence context variable: in isolation, more discriminable uncategorizable assimilation types were elicited, while in a sentence frame, Hindi contrasts tended to be classified using a single English (voiced) consonant. Speaking rate only showed modest effects on proportion of responses represented by the modal native consonants. These results highlight the sensitivity of perceptual patterns elicited in the laboratory to experimental variables.
Voice onset time of bilingual English and French-speaking Canadians
Authors: Fowler Carol , Rowland Sarah , Ostry David , Sramko Valery , Halle Pierre
Published: October 2013

There is evidence of voice onset drift when bilinguals are submerged in cultures that are dominated by their second language (L2). Sancier and Fowler [Gestural drift in a bilingual speaker of Brazilian Portuguese and English,‘‘ J. Phonet. 4, 421-436 (1997)] found that voiceless stop voice onset times (VOTs) of a bilingual speaker of Brazilian Portuguese and English were longer after months spent in the US than after time spent in the speaker’s first language (L1) context. Flege [’’The production of ‘‘new’’ and ‘‘similar’’ phones in a foreign language: Evidence for the effect of equivalence classification,‘‘ J. Phonet. 15, 47–65 (1987)] studied French L1 English L2 bilinguals and English L1 French L2 bilinguals who had spent about 12 years living in the L2 dominant culture. The French L1 English L2 bilinguals VOTs were longer than the VOTs of French monolinguals. The English L1 French L2 bilinguals VOTs were shorter than the VOTs of English monolinguals. In the present study the nature of the experience underlying VOT drift was investigated. Specifically, the aim of the current study was to see whether exposure to another language with different VOTs affects VOT production in the first (or only) language or if VOT production drift is dependent on speaking the non-native language. Productions from English and French monolinguals and from English-French bilinguals were compared across varying linguistic contexts and order of acquisition.
Consonantal context and experience effects on American L2-learners’ perception of French vowels
Authors: Levy Erika S.
Published: October 2013

According to Best’s [Best, C. T. (1994). ‘‘The emergence of native-language phonological influence in infants: A perceptual assimilation model,’’ in The Development of Speech Perception: The Transition from Speech Sounds to Spoken Words, edited by J. Goodman & H. C. Nusbaum (MIT Press, Cambridge, MA); Best, C. T. (1995) ‘‘A direct realist view of cross-language speech perception,’’ in Speech Perception and Linquistic Experience Issues in Cross-Language Research, edited by W. Strange (York Press, Baltimore, MD)] Perceptual Assimilation Model (PAM), listeners’ perceptual assimilation of unfamiliar speech sounds predicts their discrimination accuracy of these sounds. This study applied the PAM to second-language (L2) learners. Three groups of American English (AE) listeners performed a perceptual assimilation (PA) task involving Parisian French (PF) vowels /y-œ -u-o-i-ε-a/ and a categorial discrimination task involving French front versus back rounded pairs /y-u/, /y-o/, /œ -o/, /œ -u/, front rounded versus front unrounded /y-i/, /y-ε/, /œ -ε/, /œ -i/, and front rounded /y-œ /. Vowels were in bilabial /rabVp/ and alveolar /radVt/ contexts. PF front-rounded vowels were perceptually assimilated overwhelmingly to back AE vowels, resulting in more discrimination errors for front-versus back-rounded PF pairs than for front-unrounded versus rounded pairs. Listeners with formal French instruction fared similarly to listeners with no experience. Extensive immersion correlated with fewer errors than formal experience, although /u-y/ discrimination remained relatively poor for this group. More errors occurred in alveolar than bilabial context. Thus, native-language allophonic variation may explain context-specific L2 perception. Using a percent overlap method, a significant correlation was found between PA overlap and discrimination errors for all groups, suggesting that the PAM may be extended to L2-vowel learning. [Work supported by NIH.]
Robust processing against uncertain reverberation spectra in shallow-water broadband active sonars
Authors: Cable Peter G.
Published: October 2013

Broadband low-frequency active sonars operating in shallow water must work against reverberation having uncertain spectral color. Under these conditions prewhitening of the background is appropriate for detection and estimation processing. To assess the importance of prefiltering, in this talk signal-to-background performances of energy detected data subjected to no prewhitening, prewhitening, and Eckart filtering are compared for typical observed shallow-water reverberation spectral shapes. Adaptive prewhitening algorithms are described and their performances analyzed in terms of loss associated with spectral estimation errors. Modeled detection performance is compared with measured results obtained from Area Characterization Test III performed in the Korea Strait. Finally, the relevance of adaptive prewhitening to estimation for classification is also described. [Work supported by ONR and DARPA.]
Full-field likelihood ratio detection for multistatic sensors in uncertain environments
Authors: Stone Lawrence , Osborn Bryan
Published: October 2013

As small networked sonobuoys become cheaper and more viable in the submarine warfare community, there is a growing demand for techniques to automatically process detection data from dense fields containing O(100) or more sonobuoys. The presentation describes a Bayesian framework for the incoherent integration of automatic detections from these dense sonobuoy fields. This framework recursively integrates likelihood ratio functions to form a cumulative posterior over a target state space. To be most effective, these methods exploit either empirical sensor performance models or physics-based signal excess sensor performance models. The presentation describes the use of each type of performance model and presents one method for handling uncertainties associated with signal excess predictions. The method presented starts with a prior on a set of possible environmental conditions. When a target is present in the detection data, the cumulative likelihood ratio will peak in the environment most consistent with the true environment.
Performance of the estimated ocean detector (EOD) against non-Gaussian signal and noise
Authors: Jemmott Colin W. , Ballard Jeffrey A. , Sibul Leon H. , Culver R. Lee , Camin H. John , Bradley David L.
Published: October 2013

Our overall goal is to develop a method for incorporating knowledge of environmental variability into a passive sonar detector. An earlier talk presented the derivation of the estimated ocean detector (EOD), which is the maximum-likelihood detector for the exponential class of received signal parameter probability density functions (pdfs). A particular implementation of the EOD for Gaussian signal and noise (members of the exponential class) was shown and performance bounded. This talk evaluates the performance of the Gaussian EOD under nonideal conditions, including inaccuracies in the estimates of signal and noise variance, and examines robustness under received signal distributions that contain nonzero skew and kurtosis. To assess detection performance for non-Gaussian signals, receiver operating characteristics are computed for received signal pdfs obtained by applying the maximum entropy method to fit an exponential class pdf to experimental data. Gaussian EOD performance for non-Gaussian signal and noise conditions is compared to the classical envelope and correlation detectors, which form the limiting cases of the EOD. [Work supported by The Undersea Signal Processing Program, Office of Naval Research.]
High-resolution shallow water tomography using an array of sources and receivers
Authors: Roux Philippe , Cornuelle Bruce D. , Sarkar Jit , Akal Tuncay , Hodgkiss W. S. , Kuperman W. A. , Sabra Karim G. , Song Hee Chun , Stevenson Mark
Published: October 2013

During the FAF05 experiment, two vertical arrays of 29 sources and 32 receivers both covering a large part of the shallow water ocean were located 5 km from each other. A complete acquisition of the waveguide impulse responses between each source and each receiver was performed every 20 s during several hours using broadband pulses at 3.5 kHz. Using time-delay beamforming on both the source and receiver arrays, each ray path was isolated and matched to a ray code based on an a priori model of the environment. Following this approach, the impulse responses data matrices were then inverted over time to obtain a movie of the range- and depth-dependent fluctuations of the sound speed between the two arrays. Spatial resolution is discussed as a function of the number of rays used in the inversion. [Work supported by ONR.]
Single- and multi-channel underwater acoustic communication channel capacity: A computational study
Authors: Hayward Thomas J. , Yang T. C.
Published: October 2013

Acoustic communication channel capacity determines the maximum data rate that can be supported (theoretically) by an acoustic channel for a given source power and source/receiver configuration. In this paper, results reported previously [Hayward & Yang, High Frequency Ocean Acoustics Conference, AIP Conference Proceedings (American Institute of Physics, New York, 2004) for single-input, single-output (SISO) systems are reviewed. Then, channel capacities of single-input, multi-output (SIMO) and multi-input, multi-output (MIMO) systems are investigated, first in the limit of a dense receiver array spanning the entire acoustic environment and then for arrays consisting of a small number of sensors. For the dense array, the computed values of the MIMO channel capacities for a modeled shallow-water environment are found to be over 2 orders of magnitude higher than for the SISO channel. Channel capacities for smaller arrays are computed using an exact formula and then compared with approximations based on previously published results. Noise modeling issues and implications for underwater acoustic communication systems are discussed. [Work supported by the Office of Naval Research.]
Ocean variability effects on underwater communication channel
Authors: Song Aijun , Badiey Mohsen
Published: October 2013

In the recent high-frequency acoustics experiments KauaiEx and MakaiEx, it is shown that the variability of the oceanographic parameters has direct impacts on the acoustic signal propagation. For example, the variability of the sea surface condition is highly correlated with the changes of energy in the surface bounces. The coherence of the communication channel is also affected by the sea surface wave. To design an efficient communication system, the relevant ocean variability effects should be investigated. Such investigation will also lead to the prediction of the communication performance at dynamic environment. In the presented work, oceanographic parameters, including sound speed profile and sea surface condition, will be correlated with a series of channel property. Their impacts on the communication receiver, especially maximum-likelihood (ML) receivers, will be also presented. [Work supported by the ONR.]
Source localization in deep ocean using matched double-path delay method
Authors: Liu Yudong
Published: October 2013

The relationship of matched-field processing (MFP) and multipath delay localization (MDL) is described in this paper. MDL is a kind of sim- plification of MFP. A method of analyzing multipath structure is presented in this paper. The coincidence between the theory prediction and experiment data shows that the method and program could be used to determine multipath time-delay structure. A realistic method called L2 norm match algorithm for MDL is developed. The depth-range ambiguous figures are pretty good. Comparison between the match method of absolute delay and relative delay shows that the performance of the latter is better. In the case of known source depth, a double-path match plan is given here. It is easy to determine the source distance from the range-delay curves. Many experiments have shown that the error is less than 6% within the range of 30 km and less than 10% within the range of 40 km. The influence caused by mismatch of ocean environment parameters and receiver configuration on double-path ranging is analyzed.
An experimental study of how paint affects the specific airflow resistance and visual appearance of nonwoven scrims on acoustical ceiling tiles
Authors: Frantz William , Wiker Anthony
Published: October 2013

This study explores how paint affects the specific airflow resistance and visual appearance of nonwoven scrims used on acoustical ceiling tile. Nine different scrims are included. Each scrim is finished with two application rates of paint. The specific airflow resistance is measured by the ASTM C522 method. The painted samples are also scanned and the images processed by ImagePro software to characterize visual aspects such as number of features, area of features, and roundness. It is found that specific airflow resistance and visual responses can be correlated to the resistance of the unpainted scrim, the surface tension characteristics of the scrim and paint, and the application rate of the paint. The resulting empirical models can be used to understand design tradeoffs between airflow resistance and visual impact.
Maximum length sequences versus random telegraph noise in measuring impulse responses and transfer functions
Authors: Aaronson Neil L. , Hartmann William M.
Published: October 2013

Maximum length sequences (MLS) are commonly used to measure impulse responses and transfer functions of linear systems. The remarkable utility of the MLS comes from the property that its autocorrelation is approximately a delta function, and this approximation becomes more valid for higher orders (lengths) of MLS. However, the autocorrelation of a random telegraph noise (RTN) sequence also approaches a delta function in the long-sequence limit. Advances in computer hardware make it possible to use long sequences of RTN. Consequently one wonders if the MLS still confers an advantage. This study presents a quantitative analysis of the accuracy of MLS and RTN for all lengths up to 2N−1=262,143. RTN sequences were generated by scrambling the elements of an MLS. A special case wherein the approximate length of the impulse response is prior knowledge allows the measured impulse response to be windowed. Even with this advantage applied to RTN (but not to MLS), MLS measurements are clearly more accurate. The numerical experiments conclude than any MLS sequence longer than the impulse response outperforms a RTN of any practical order by an order of magnitude. [Work supported by the NIDCD grant DC 00181.]
Energy-based field quantities in reverberation chamber measurements
Authors: Nutter David , Leishman Timothy , Abbott JohnPaul
Published: October 2013

Traditional reverberation chamber measurements, such as sound power and sound absorption measurements, rely on the evaluation of acoustic pressure at many field positions. Other field quantities could be better suited for these applications if they had greater spatial uniformity and required fewer source-receiver positions to produce accurate measurement results. This paper explores the possibility of using energy-based field quantities for this purpose and provides several analytical and experimental results to show their benefits.
Absorption-based scaling method to predict steady-state broadband sound fields in enclosures
Authors: Bliss Donald , Rouse Jerry , Franzoni Linda
Published: October 2013

An absorption-based analysis method is developed for steady-state broadband sound fields in enclosures having diffuse or specular reflection boundaries. The wall absorption is expressed as an overall spatially averaged value, with spatial variations around this mean. Interior pressures and intensities are expressed in a power series of the overall absorption, treated as a small parameter, thereby giving a separate problem at each order. The first problem has a uniform mean-square pressure level proportional to the reciprocal of the absorption parameter, as expected. The second problem gives a mean-square pressure and intensity distribution that is independent of the absorption parameter and is primarily responsible for the spatial variation of the reverberant field. This problem depends on the location of sources and the spatial distribution of absorption, but not absorption level. Higher-order problems proceed at powers of the absorption parameter, but are essentially small corrections to the primary spatial variation. The primary spatial variation problem is solved using two different methods. Although formally developed based on treating absorption as a small parameter, the method is demonstrated to work remarkably well in practice up to large absorptions, and to provide insight into the behavior and design of acoustic spaces.
Acoustically responsive fibers in the mammalian vestibular nerve
Authors: Guinan John J.
Published: October 2013

There are afferent fibers in the vestibular nerve of cats and guinea pigs that respond to sound at levels within the normal range of hearing. Most acoustically responsive fibers are in the inferior vestibular nerve and have irregular spontaneous activity, although not as irregular as cochlear afferents. Single-fiber labeling shows that acoustically responsive, irregularly discharging (ARID) fibers originate in the saccule. ARID fibers traced centrally arborized extensively in vestibular nuclei and ventromedial to the cochlear nucleus. ARID fibers had broad, V-shaped tuning curves with best frequencies between 500 and 1000 Hz, thresholds of 90 dB SPL or more, and shapes comparable with tuning-curve tails of cochlear afferents. ARID fibers synchronized to a preferred phase of the tone cycle at levels approximately 10 dB lower than their firing-rate threshold. ARID spike rates increased monotonically with sound level without saturating at 115 dB SPL. Acoustic clicks evoked spikes in ARID fibers with minimum latencies less than 1.0 ms. Contraction of the middle-ear muscles decreased responses to sound, consistent with the sound transmission path being through the middle ear. In summary, there is strong evidence that the mammalian saccule responds to sound and sends acoustic information to the central nervous system. [Work supported by NIDCD RO1DC00235.]
Evidence for near-field hearing in crocodilian vocal communication: Intensity of the American alligator (Alligator mississippiensis) vocal display
Authors: Todd Neil P. McAngus
Published: October 2013

The aim of this study was to carry out an acoustic analysis of alligator vocal displays recorded simultaneously in air and water in order to estimate the role of the sacculus in crocodilian acoustic communication. Crocodilians are interesting animals to study as they are aquatic, highly vocal, and morphologically have a large sacculus. Alligators, in particular, are known to be one of the most vocal species. Previous studies of alligator hearing in air and water have indicated a maximum sensitivity between 800 and 1000 Hz [Higgs et al., J. Comp. Physiol. 188, 217–223 (2002)]. Analysis of alligator vocalizations, however, indicates that most of the power in adult vocalizations in water is typically between 30–50 Hz. These results leave the very real possibility that the basilar papilla may not be the primary receptor during crocodilian water-borne communication. At 1-m distance peak SPLs of 140 dB can be obtained in water and, in conjunction with existing threshold data, the effective radius of saccular acoustic sensing of the above source can be estimated to be approximately 30 m, which is easily greater than the typical distance between performer and receiver animals during a display.
Online acoustic parameter extraction and annotation for a marine sound collection
Authors: Smith Shelagh A. , Bradbury Jack W.
Published: October 2013

After 3 years of archival and with the collaboration of more than 20 researchers and institutions, the online marine sound collection at the Macaulay Library, Cornell Lab of Ornithology, is now in a proof of concept phase. This presentation introduces the new annotation and acoustic parameter extraction and retrieval tools. It is further explained how these tools are used for fine-grain searches and recovery of specific sounds within long recordings while online. Also included is a description of the online open access model and delivery mechanism. [Work supported by ONR and NSDL.]
Feature normalization for robust individual identification of the ortolan bunting (emberiza hortulana L)
Authors: Adi Kuntoro , Johnson Michael T.
Published: October 2013

This paper presents the use of cepstral moment normalization for the purpose of improving the accuracy of individual identification in the ortolan bunting (emberiza hortulana L). The underlying classification algorithm is based on hidden markov models (HMMs) using Greenwood function cepstral coefficients (GFCCs), and the proposed feature normalization is implemented via a combination of cepstral mean subtraction and cepstral variance normalization, which are equivalent to a statistical z-score normalization across each example utterance. Results indicate a significant reduction in error on the individual identification task, improving accuracy from 89% to 96% in initial experiments, using a single call type over a small population of 6 individuals.
Tracking fish motion and behavior with acoustic flow
Authors: Jagannathan Srinivasan , Symonds Deanelle , Lee Sunwoong , Makris Nicholas C. , Donabed Ninos , Ratilal Purnima
Published: October 2013

Fish populations in the New Jersey continental shelf have been continuously monitored over thousands of square kilometers using acoustic waveguide remote sensing techniques [Makris et al., ‘‘Fish population and behavior revealed by instantaneous continental-shelf-scale imaging,’’ Science 311, 660–663 (2006)]. Here, we explore the approaches for tracking both large shoals and smaller isolated fish groups over space and time from images of fish population density. One method uses density thresholds to segment coherent population centers and track their centroids. These data are then used to compute differential velocities between population centers and to determine the rate at which information may be transmitted across a population center. We also examine the possibility of applying optical flow concepts from machine vision [Horn, B. Robot Vision, MIT Press, 1986], as a global approach for estimating fish velocity at every pixel in the fish density image. The analogous acoustic flow is computed based on changes in acoustic intensity over space and time. Acoustic flow automatically tracks fish motion within a school or shoal and migration across fish bridges connecting shoals segments. We also investigate the possibility of using acoustic flow for navigating the ocean environment and correcting for errors in charting acoustic returns, for instance caused by array-heading sensor.
Assessing fish populations and enhancing biological detection in continental shelf environments with range-dependent scattering and reverberation models
Authors: Andrews Mark , Galinde Ameya , Donabed Ninos , Ratilal Purnima , Chen Tianrun , Symonds Deanelle , Lee Sunwoong , Makris Nick
Published: October 2013

Fish populations in continental shelf environments can be continuously imaged over thousands of square kilometers using acoustic waveguide remote sensing techniques [Makris et al., Science, Feb. (2006)]. A calibrated range-dependent scattering and reverberation model [Ratilal et al., J. Acoust. Soc. Am. 114, 2302 (2003)] based on the parabolic equation has been applied to assess population densities of fish by inverting long-range acoustic data collected on the New Jersey continental shelf. This model is now applied to predict the types of fish species and zooplankton that are detectable in a general range-dependent continental shelf environment, including the resolution and accuracy that can be expected in estimating fish population densities and for differentiating fish species. We consider different geometries of the source and receiving array to enhance biological detection and reduce background reverberation in highly range-dependent environments. Using multiple source frequencies, the possibility of distinguishing fish species based on their differing scattering characteristics and resonance frequencies will be examined.
Modeling of acoustically enhanced bubble growth in supersaturated biological media
Authors: Ilinskii Yurii A. , Hamilton Mark F. , Wilson Preston S.
Published: October 2013

Recent measurements and predictions of dissolved nitrogen concentration in tissues of dolphins and whales following repeated dives have indicated that the gas concentration may reach 300% of saturation [Houser et al., ‘‘Can diving-induced tissue nitrogen supersaturation increase the chance of acoustically driven bubble growth in marine mammals?,’’ J. Theor. Biol. 213, 183–195 (2001)]. This has generated renewed interest in whether underwater sound may increase the likelihood of decompression sickness in these cetaceans. One potential mechanism is bubble growth due to rectified diffusion. Eller and Flynn [‘‘Rectified diffusion during nonlinear pulsations of cavitation bubbles,’’ J. Acoust. Soc. Am. 37, 493–503 (1965)] modeled rectified diffusion by solving a Rayleigh-Plesset equation for the acoustically driven bubble dynamics, coupled to a quasianalytical diffusion model that accounts for increase of the equilibrium bubble radius. Crum and Mao [‘‘Acoustically enhanced bubble growth at low frequencies and its implications for human diver and marine mammal,’’ J. Acoust. Soc. Am. 99, 2898–2907 (1996)] used similar models to consider dissolved gas saturations up to 223% and demonstrated significantly enhanced bubble growth at sound-pressure levels above 210 dB (re: 1 μPa). We are revisiting this problem by extending these models and considering wider ranges of parameters. A principal difference is that the gas diffusion is modeled by solving the full partial differential equation numerically. Not only does this approach circumvent analytical approximations, it permits taking into account variations in gas concentration associated with dive-profile-dependent hydrostatic pressure variations. [Work supported by ONR.]
Gas-filled microbubbles—Contrast agents for targeted molecular imaging
Authors: Klibanov Alexander L. , Hossack John , Cho Yun K. , Yang William C. , Rychak Joshua J. , Ley Klaus F.
Published: October 2013

Microbubble contrast agents suitable for targeted molecular imaging have been described. Commonly used agents are gas-filled micron-size bubbles. Targeting ligands (antibodies, peptides, or proteoglycans) are coupled to the contrast particles and ensure firm attachment of microbubbles to intravascular regions of interest. Targeting is directed to selectins or integrins upregulated on vascular endothelium in the areas of pathology (inflammation, ischemia-reperfusion injury, or angiogenesis). Real-time imaging has been performed in animal models with sub-millimeter spatial resolution. Detection sensitivity for targeted microbubble contrast is superb: single bubbles (pg mass) can be visualized by ultrasound. Successful retention of microbubbles on the target is dependent on the target receptor surface density as well as targeting ligand surface density on the bubbles. To improve targeting efficacy, microbubbles can be outfitted with fast-binding ligands (such as P-selectin glycoprotein ligand-1 analogs) in addition to slow but firmly binding ligands (such as antibodies). Ultrasound irradiation also improves efficacy of targeting, especially in high shear conditions. In addition to imaging, microbubbles can be applied for drug and gene delivery purposes: interaction of ultrasound and bubbles can be used for in situ targeted deposition, activation and release of pharmaceutical agents [Disclosures: ALK, JJR, and KFL: Targeson stock ownership. ALK: Philips Research grant.]
Musical coffee mugs, singing machines, and laptop orchestras: New paradigms for musical expression
Authors: Cook Perry
Published: October 2013

Advances in algorithms, hardware, and sensors now allow us to build new types of expressive musical devices based around small computer systems. These new ‘‘instruments’’ can leverage and extend the expertise of virtuoso performers, expand the palette of sounds available to composers, and encourage new ideas and participation from the young or the musically untrained. New musical instuments can take the form of augmentations of traditional musical instruments, whimsical objects made by augmenting everyday nonmusical objects, or entirely new paradigms for making and controlling sound. Wired and wireless networking can provide opportunities, yet pose significant challenges, for new forms of ‘‘orchestral’’ expression. This talk will look at a variety of musical technologies, devices, systems, compositions, and performances we have created at Princeton in the last 10 years or so. Lots of audio/video examples, as well as actual live demonstratons, will be presented.
Mapping strategies for sound synthesis, digital audio effects, and sonification of performer gestures
Authors: Verfaille Vincent , Wanderley Marcelo M.
Published: October 2013

Mapping strategies are an essential step when designing realtime musical performance systems, as well as offline digital sound processing. These strategies define how we relate input device parameters to sound synthesis or audio effect parameters. This implies the ability to combine input parameters among themselves (parameter combination) and valid control signals in terms of range, variation type, etc. (signal conditioning). Recent works highlighted the interest of multi-layer mapping strategies in the context of digital musical instruments, which can also be applied in the context digital audio effects. In this presentation, three strategies will be discussed in order to illustrate the role of mapping strategies in various contexts. The first example concerns an additive synthesizer called Ssynth, a further development of Escher, a prototyping system aiming at studying the effect of mapping strategy in instrument design. The second example is a general mapping strategy for digital audio effects, allowing for both adaptive and gestural control. The final example concerns sonification of gestures, used to provide cues about ancillary movements of performers. For each example, mapping strategies will be explained in terms of their structure and functionality. [Work supported by FQRNT and MDEIE PSR-SIIRI (Québec, Canada), CNRS and PACA (France).]
Deriving individualized control over music synthesis via inversion of psychophysical scaling results
Authors: Martens William L.
Published: October 2013

Computer-based interactive music generation systems have an advantage over acoustic instruments with respect to the flexibility of the human interface for their control. Whereas human performers must conform to the relatively invariant constraints of acoustic instruments, a computer interface can be rapidly updated with regard to changes in user preferences and performance requirements. This paper will describe a software environment that executes miniature psychophysical scaling experiments for a single user of an interactive music generation system in order to derive individualized control over music synthesis via inversion of the obtained psychophysical scaling results. A case study will be presented in which the system has been used to control parametric synthesis of musical timbres using an electronic musical keyboard, providing automatic perceptual mapping of synthesis parameters within their musically useful range. More in-depth exploration of the timbral similarities between a user-selected set of synthesis patches resulted in low-dimensional control structures that could be used to organize musical timbres in preparation for composition or performance.
The method for capturing tilt signal of musical instruments using light sensor
Authors: Kim Moonseok
Published: October 2013

Players of musical instruments used to express their intuition and emotion not only by playing style but also the motion of the instrument’s body. Furthermore, on the ensemble, this gesture plays a role as a language to communicate to each other. Substituting some players for a computer is one part of the information to make interactions between human players and computer. To get them, tilt sensors which catch accelerations are used in general. They are used to generate underdamped signal and have to apply LPF for acquiring stable responses. This method results in delay and may affect temporal difficulties on ensemble. If the light source of the performance room is directional, the light intensity signal that is caught at photoresistors on two or more points of the instrument’s surface can be used to calculate the amount of tilting. The photoresistor senses the light intensity which is determined by the distance from the light source, and differences on each value represent relative angle according to the light source direction.