bluuebunny/crossref_metadata_2025 huggingface dataset:
Phonetic representation of frequent function words in 8-month-old infants
Authors: Shi Rushen , Werker Janet , Cutler Anne
Published: September 2013

Recent work by a number of researchers showed that even preverbal infants detect and recognize functors in continuous speech. In our research, English-learning infants aged 11 to 13 months, but not 8 months, recognized frequent and infrequent functors as a class, and represented them in segmental detail (Shi et al., 2003; Shi et al., 2004). Here we report a study on 8-month-old infants’ recognition and representation of high versus low frequency functors. Infants heard sequences containing a lexical word preceded by a high frequency functor ‘‘the,’’ versus a nonsense functor ‘‘kuh,’’ differing from ‘‘the’’ only in the initial consonant, with the prosody unchanged. Another group of 8-month-olds heard sequences containing a lexical word preceded by a low frequency functor ‘‘its,’’ versus a nonsense functor ‘‘ots.’’ Recognition of functors would be indicated by longer listening time to sequences containing real functors. Results reveal no differential listening time between ‘‘the+lexical word(LW)’’ and ‘‘kuh+LW,’’ nor between ‘‘its+LW’’ and ‘‘ots+LW;’’ however, ‘‘the+LW’’ and ‘‘kuh+LW’’ together induced longer listening time than ‘‘its+LW’’ and ‘‘ots+LW.’’ We conclude that 8-month olds recognize the frequent, familiar ‘‘the’’ in continuous speech, but it is underspecified phonetically in infants’ initial lexicon. Our previous work indicates detailed specification by 11 months.
Cross-language perceptual category mapping: Korean perception of English obstruents
Authors: Park Hanyong , de Jong Kenneth , Silbert Noah
Published: September 2013

Models, such as SLM and PAM, predict that performance on second language sounds is determined by the perceptual relationship of the sounds to the original language categories. To measure this relationship, Schmidt [J. Acoust. Soc. Am. 99, 3201–3211] had native Korean speakers classify English consonant productions into Korean orthographic categories, and assess the similarity of the consonants to the chosen categories. The current experiment further examines how Korean labeling relates to accuracy in using English orthographic categories. Results show Koreans poorly identify sounds rated as dissimilar from Korean categories. Similarly, sounds that are inconsistently labeled with Korean labels are less accurately identified. These results suggest that accuracy varies with the nearness of the English and a Korean category, and thus English categories are developed from original Korean categories. However, other results indicate that sounds straddling Korean categories can be very accurately labeled, suggesting a complete suppression of native contrasts. In addition, identification accuracy for subjectively odd sounds can be very high, suggesting the development of a new category. Similarly, cases in which both Korean and English labeling is inconsistent show no relationship between the Korean and the English labels, indicating that the English categories are constructed apart from the existing Korean categories.
Performance predictions for acoustic communication using passive phase conjugation
Authors: Rouseff Daniel
Published: September 2013

Passive phase conjugation processing for acoustic communication combines temporal matched filtering with spatial diversity. An efficient decision-directed procedure has been implemented to calculate the matched filters and has been applied successfully to experimental data. In the present paper, a model is developed for the expected mean-squared error in the demodulation output. A normal mode expansion is used for the phase-encoded acoustic field. The matched filter integration is evaluated using a stationary phase approximation. This intermediate result is interpreted using the waveguide invariant. After combining across the array and sampling, formal statistical averages of the demodulation output are calculated. Results are parametrized in terms of the number of array elements and their spatial distribution. The effects of truncating the matched filters and reducing the bandwidth are also quantified. Performance predictions are shown to be in good agreement with experimental results. [Work supported by ONR under the ARL program.]
Performance comparisons between passive-phase conjugation and decision-feedback equalizer for underwater acoustic communications
Authors: Yang T. C.
Published: September 2013

Passive-phase conjugation (PPC) uses passive time reversal to remove intersymbol interferences (ISI) for acoustic communications in a multipath environment. It is based on the theory of signal propagation in a waveguide, which says that the Green function (or the impulse response function) convolved with its time-reversed conjugate, summed over a large aperture vertical array of receivers is a delta function in space and time. A decision feedback equalizer (DFE) uses a nonlinear filter to remove ISI based on the minimum mean square errors (MSE) between the estimated and the true (or decision) symbols. These two approaches are motivated by different principles. In this paper, we analyze both using a common framework, illustrating the commonality and differences, pro and con between the two methods, and compare their performances in realistic ocean environments. The performance measures are MSE, output signal-to-noise ratio and bit error rate (BER) as a function of the number of receivers. For a small number of receivers, DFE outperforms PPC in all measures. As the number of receivers increases the BER for both processors approaches zero, but at a different rate. The results are supported by both simulated and real data. [Work supported by ONR.]
Reliable Doppler-spread estimation using an evolutionary algorithm for underwater acoustic communications over channels with frequency-selective fading
Authors: Dhanoa Jasdeep S. , Ormondroyd Richard F. , Hughes Evan J.
Published: September 2013

There is a pressing need for reliable wideband underwater acoustic communication for enhanced performance of diver communications, underwater networks, control links to ROVs and data links to remote sensors and AUVs. The performance of such links is compromised by the doubly-spread acoustic channel, where multipath time-delay spread causes inter-symbol interference due to frequency-selective fading and Doppler-spread results in additional signal distortion and temporal variation of the channel characteristics. However, if the channel characteristics can be estimated accurately, especially the Doppler-spread, many of these problems can be resolved. Doppler-spread occurs because the Doppler velocity may be different on each path. The paper describes a method for improved-reliability Doppler spread estimation of channels that experience frequency-selective fading. The method uses a wideband sounding signal to overcome the frequency selective fading and the estimation of the Doppler spread is obtained from this complex waveform using multi-layered optimization based on evolutionary algorithms. The method has a wide dynamic range and can estimate the Doppler shift of weak multipath components in the presence of strong multipath components. The accuracy of the Doppler-spread estimate is not limited by the short duration of sounding signal and the method performs well even in the presence of significant noise.
Design of a symmetric multicarrier modulation for underwater acoustic communications
Authors: Wang Yi
Published: September 2013

Mobile underwater acoustic (UWA) channels always exhibit large delay spread and Doppler spread. Multicarrier modulation is an efficient technique for the communications over multipath channels. However, the orthogonality of the transmit signals, e.g., OFDM signals, will be destroyed by the Doppler spread and interference will be produced. Thus, an equalizer is required in the receiver. For this reason, we argue that multicarrier modulation with Gaussian pulse (symmetric in time and frequency domains) as the transmit filter is more suitable for the UWA communication systems than the OFDM. The key problem for the multicarrier modulation is to design/optimize the number of carriers and the parameter alpha in the Gaussian pulse which will greatly affect the system performance. In this paper, we investigate the optimization problem for four kinds of channels: AWGN channel, frequency-selective channel, time-selective channel and doubly selective channel. Channel information is assumed known in the transmitter by feedback. Analytical results are obtained and the numerical examples are given. To achieve the cost function, a 2D MMSE-DFE equalizer is used. Finally, we propose the balanced design for the practical engineering.
Underwater acoustic communication experimentation: The acoustic communications and data storage (ACDS) system
Authors: McCord M. , Schindall J. , Yang T. C. , Gendron P. , Yang W.-B.
Published: September 2013

The Naval Research laboratory has developed a sea-going system, currently consisting of three acoustic communications and data storage (ACDS) buoys. The buoys can be deployed in the water column, moored to the ocean floor, or towed behind a ship to emulate an autonomous underwater vehicle (AUV). The system is intended for semi-real-time acoustic communications in situ and continuous recording of the raw acoustic data in the water for postexperiment analysis. The purpose is to study environmental issues affecting high data rate point-to-point acoustic communications as well as multiple-in-multiple-out acoustic networking. Each ACDS has an acoustic projector and an array of eight hydrophones. It is designed for two frequency bands: 2–5 kHz and 15–25 kHz. The system has been deployed in several oceans. Modulation signals used include binary and quadrature phase-shifted keying (BPSK/QPSK), frequency-hopped frequency-shifted keying (FH FSK), orthogonal frequency division multiplexing (OFDM) and code division multiple access (CDMA) signals. The acoustic modem is based on the Acoustic Modem Software developed by WHOI and improved by the Naval Underwater Warfare Center, Newport, RI. Acoustic networking signals are used to aid vehicle navigation. [Work supported by ONR.]
Environmental and motion effects on orthogonal frequency division multiplexed signaling
Authors: Gendron Paul J. , Yang T. C.
Published: September 2013

The use of tightly spaced orthogonal tones for communication through shallow water allows for diverse modulation strategies, from moderately efficient noncoherent on–off keying to fully coherent signaling. Critical to the effectiveness of orthogonal frequency division multiplexed (OFDM) schemes is the estimation of both source dilation, due to source–receiver relative motion, and the channel tranfer function. A dilation process estimator based on a spline model of dilation is presented and when coupled with decision directed channel estimation communication reliability is improved. The method is tested on OFDM signaling schemes at 18 kHz center frequency and 4 kHz bandwidth under diverse source motion scenarios and ranges during MREA(03) experiements off the north coast of Elba, Italy. Channel probing experiments characterize the environment in terms of coherence time, multi-path delay and angle spread. The quantitative effect of frequency selectivity and coherence time on the performance of OFDM signaling is addressed. Bit error rates are reported. [Work supported by ONR.]
Off-axis signal processing of cetacean biosonar
Authors: Zimmer Walter M. X.
Published: September 2013

Echolocation or biosonar plays a fundamental role for odontocetes to probe their environment, and their characteristics have been studied extensively for over 40 years. In summary, cetacean biosonar can be modeled as broadband transient-like signals radiating from a finite piston or aperture. The resulting sonar beam is directional, with a directivity index exceeding 25 dB for some species. The estimation of relevant sonar parameters is usually obtained from animals that are kept within a controlled and well-instrumented environment. This paper shows how measurements of opportunity from free-ranging odontocetes may be used to obtain their relevant biosonar parameters, in particular directivity index and source level. Frequently these measurements are made with a single hydrophone that is sufficiently deep so that surface-reflected echoes separate from the direct arrival of the echolocation clicks. Also, the received signal often fades in and out as the sonar beam of the scanning animal crosses the hydrophone. The presented technique exploits this scanning and the observation that broadband signals from a finite aperture will appear distorted when recorded off the acoustic axis, as the transfer function of the aperture modifies the spectrum of the transmitted signal.
Measurement of effects on tone with lip-protecting music splints for wind instrument players
Authors: Katada Chigusa , Nozaki Kazunori , Imai Miharu , Kawamoto Masayuki , Shima Yuko , Tamagawa Hiroo , Maeda Yoshinobu , Ohboshi Naoki , Toda Tadao
Published: September 2013

To protect against lip trauma from wind instruments, music splints that cover the sharp edges of incisor teeth are often manufactured by dentists. Wind instrument players who have installed these custom-made music splints often express not only their lip comfort but also changes in their tone quality. In this study, we investigated the effect of the splints to the tone quality. We recorded three types of trumpet sounds such as long tones, arpeggios with perfect fifth, and tonguing tones with and without using a splint, respectively, by a professional trumpet player in an anechoic room. After fast Fourier transform, the higher harmonics was observed more in the splint group than in the nonsplint group, with sharp peaks from 5000 to 8000 Hz. We also examined the differences of these sound groups with recognition tests by two groups of listeners such as professional musicians and nonprofessional persons. Though sound-pressure levels of higher harmonics in two sound groups were lower than those at 400 to 2000 Hz, the musically trained persons recognized the difference perfectly. These results suggest the target of measurement to evaluate the effect of music splints.
Noise policy: Past and present
Authors: Lang William W.
Published: September 2013

Leo Beranek and the firm Bolt Beranek and Newman have played a defining role in the formulation of noise policy in America. The firm that he and Richard Bolt founded in 1948 with fewer than a half-dozen others grew to become the world’s largest acoustical consulting firm with more than 2000 employees. Two decades later in 1971, Leo Beranek was a key founder of the Institute of Noise Control Engineering of the U.S.A. The Institute, which inaugurated the INTER-NOISE series of annual noise congresses in 1972 under Beranek’s direction, played a major role in the enactment by the Congress of the Noise Control Act of 1972. NCA-72 identified the Environmental Protection Agency as the leading Federal agency with oversight responsibilities responsible for implementing the noise policies defined by the Congress. In 1981, funding for EPA’s noise program was withdrawn. Since then, leadership at the Federal level for implementing a coordinated national noise policy has been absent, but a dozen Federal agencies remain active in the noise field. With the exception of aircraft, no product emission regulations on major sources of noise are enforced today. To rectify this situation, Leo Beranek has recently been playing a leadership role in a concerted effort to rejuvenate America’s national noise policy.
Optical measurement of acoustic streaming in a standing wave with a temperature gradient
Authors: Thompson Michael W. , Atchley Anthony A.
Published: September 2013

Laser Doppler anemometry (LDA) with burst spectrum analysis (BSA) is applied to the measurement of Rayleigh-type acoustic streaming in a cylindrical standing-wave resonator constructed partly of glass and filled with air. The resonator is driven sinusoidally, and the axial component of the streaming-velocity field is measured along the resonator’s axis and across its diameter. At large acoustic amplitudes, distortion of the streaming field is observed. This distortion is attributed to two effects: (1) fluid inertia and (2) a steady temperature gradient resulting from thermoacoustic heat transport along the resonator’s inner wall. Measurements of the streaming field are made at several different acoustic amplitudes and with the resonator either wrapped in foam insulation, suspended within an air-filled tank, or surrounded by a water jacket in order to control the magnitude of the temperature gradient.
Lateralization of the Huggins pitch
Authors: Zhang Peter Xinya , Hartmann William M.
Published: September 2013

The lateralization of the Huggins pitch (HP) was measured using a direct estimation method. The background noise was initially N0 or Nπ, and then the laterality of the entire stimulus was varied with a frequency-independent interaural delay, ranging from −1 to +1 ms. Two versions of the HP boundary region were used, stepped phase and linear phase. When presented in isolation, without the broadband background, the stepped boundary can be lateralized on its own but the linear boundary cannot. Nevertheless, the lateralizations of both forms of HP were found to be almost identical functions both of the interaural delay and of the boundary frequency over a two-octave range. In a third experiment, the same listeners lateralized sine tones in quiet as a function of interaural delay. Good agreement was found between lateralizations of the HP and of the corresponding sine tones. The lateralization judgments depended on the boundary frequency according to the expected hyperbolic law except when the frequency-independent delay was zero. For the latter case, the dependence on boundary frequency was much slower than hyperbolic. [Work supported by the NIDCD grant DC 00181.]
Performance benefits of adaptive, multimicrophone, interference-canceling systems in everyday environments
Authors: Desloge Joseph G. , Zimmer Martin J. , Zurek Patrick M.
Published: September 2013

Adaptive multimicrophone systems are currently used for a variety of noise-cancellation applications (such as hearing aids) to preserve signals arriving from a particular (target) direction while canceling other (jammer) signals in the environment. Although the performance of these systems is known to degrade with increasing reverberation, there are few measurements of adaptive performance in everyday reverberant environments. In this study, adaptive performance was compared to that of a simple, nonadaptive cardioid microphone to determine a measure of adaptive benefit. Both systems used recordings (at an Fs of 22050 Hz) from the same two omnidirectional microphones, which were separated by 1 cm. Four classes of environment were considered: outdoors, household, parking garage, and public establishment. Sources were either environmental noises (e.g., household appliances, restaurant noise) or a controlled noise source. In all situations, no target was present (i.e., all signals were jammers) to obtain maximal jammer cancellation. Adaptive processing was based upon the Griffiths–Jim generalized sidelobe canceller using filter lengths up to 400 points. Average intelligibility-weighted adaptive benefit levels at a source distance of 1 m were, at most, 1.5 dB for public establishments, 2 dB for household rooms and the parking garage, and 3 dB outdoors. [Work supported by NIOSH.]
The general 2-D moments via integral transform method for acoustic radiation and scattering
Authors: Smith Jerry R. , Mirotznik Mark S.
Published: September 2013

The moments via integral transform method (MITM) is a technique to analytically reduce the 2-D method of moments (MoM) impedance double integrals into single integrals. By using a special integral representation of the Green’s function, the impedance integral can be analytically simplified to a single integral in terms of transformed shape and weight functions. The reduced expression requires fewer computations and reduces the fill times of the MoM impedance matrix. Furthermore, the resulting integral is analytic for nearly arbitrary shape and weight function sets. The MITM technique is developed for mixed boundary conditions and predictions with basic shape and weight function sets are presented. Comparisons of accuracy and speed between MITM and brute force are presented. [Work sponsored by ONR and NSWCCD ILIR Board.]
Improved theory for acoustic radiation from a stiffener attached to a plate
Authors: Haberman Robert C.
Published: September 2013

A flexural wave in a plate that interacts with a stiffener produces sound. Physically the stiffener provides concentrated line forces and moment onto the plate that generates a subset of waves with wave numbers less than the acoustic wave number. Typically the stiffener is modeled as a beam containing bending and torsional waves and mathematically coupled to the flexural waves in the plate. In reality, however, the stiffener exhibits resonant modes and is coupled to in-plane compression and shear waves in the plate. These effects produce in-plane forces at the plate–stiffener line junction (i.e., shear tractions), and highly frequency-dependent interaction forces and torques that result in complex frequency-dependent sound waves along with scattered and transmitted waves in the plate and stiffener. The theory associated with resonant stiffeners fully coupled to all three waves types in a plate with heavy fluid loading is presented, along with several numerical examples. The examples will demonstrate the conditions under which the simpler models are valid and conditions that require more sophisticated modeling. Application of the theory to problems in statistical energy analysis is briefly discussed.
A broadband energy-based boundary element method for predicting vehicle interior noise
Authors: Franzoni Linda , Rouse Jerry , DuVall Tracy
Published: September 2013

Efficient calculation of vehicle interior noise is a challenging task. Classical acoustic boundary element calculations become costly at high frequencies due to the very large number of elements required and must be solved repeatedly for broadband applications. An alternative energy-intensity boundary element method has been formally developed that employs uncorrelated broadband directional intensity sources to predict mean-square pressure distributions in enclosures. The boundary source directivity accounts for local correlation effects and specular reflection. The method is applicable to high modal density fields, but it is not restricted to the usual low-absorption, diffuse, and quasi-uniform assumptions. The approach can accommodate fully specular reflection, or any combination of diffuse and specular reflection. This new method differs from the classical version in that the element size is large compared to an acoustic wavelength and equations are not solved on a frequency-by-frequency basis. These differences lead to an orders-of-magnitude improvement in computational efficiency. In vehicle interiors the sources are typically the vibrating walls of the enclosure. A special treatment for wall vibration sources has been developed for use with the new boundary element method. Calculations of spatially varying mean-square pressures agree well with computationally intensive modal solutions.
The stop voicing contrast in French: From citation speech to sentencial speech
Authors: Abdelli-Beruh Nassima , DeMaio Eileen , Hisagi Miwako
Published: September 2013

This study explores the influence of speaking style on the salience of the acoustic correlates to the stop voicing distinction in French. Monolingual French speakers produced twenty-one C_vC_ syllables in citation speech, in minimal pairs and in sentence-length utterances (/pa/—/a/ context: /il a di pa C_vC_ a lui/; /pas/—/s/ context: /il a di pas C_vC_ sã lui/). Prominent stress was on the C_vC_. Voicing−related differences in percentages of closure voicing, durations of aspiration, closure, and vowel were analyzed as a function of these three speaking styles. Results show that the salience of the acoustic−phonetic segments present when the syllables are uttered in isolation or in minimal pairs is different than when the syllables are spoken in a sentence. These results are in agreement with findings in English.
Contextual sensitivity of some acoustic correlates to the stop voicing distinction in French
Authors: Abdelli-Beruh Nassima
Published: September 2013

This study examined how monolingual French speakers produced the stop voicing distinction in syllable-initial and syllable final stops embedded in various sentence contexts. Voicing-related differences in percentages of closure voicing, durations of aspiration, closure, and vowel were analyzed as a function of two experimental variables: the voicing class of the sound adjacent to the target stop [voiced vowel (/pa/—/a/ context), voiceless consonant (/pas/—/s/ context)] and the position of the stop within a syllable (syllable-initial, -final). Results from ANOVA showed that despite variations among speakers, group-based patterns surfaced in three contexts (i.e., syllable-initial stops in the /pa/—/a/ and /pas/—/s/ contexts and syllable-flnal stops in the /pa/—/a/ context): /b, d, g/ were more aspirated, preceded by longer vowels and were more frequently phonated than /p, t, k/. Closure durations for /b, d, g/ were shorter than those for /p, t, k/ in the /pa/-/a/ context only. Group patterns were not found for syllable-final stops in the /pas/-/s/ context. Results from discriminant analyses indicated that closure voicing was the variable that contributed the most to the phonological voicing distinction in all conditions.
Effects of coda voicing and aspiration on Hindi vowels
Authors: Lampp Claire , Reklis Heidi
Published: September 2013

This study reexamines the well-attested coda voicing effect on vowel duration [Chen, Phonetica 22, 125–159 (1970)], in conjunction with the relationship between vowel duration and aspiration of codas. The first step was to replicate the results of Maddieson and Gandour [UCLA Working Papers Phonetics 31, 46–52 (1976)] with a larger, language-specific data set. Four nonsense syllables ending in [open-o] followed by [k, kh, g, gh] were read aloud in ten different carrier sentences by four native speakers of Hindi. Results confirm that longer vowels precede voiced word-final consonants and aspirated word-final consonants. Thus, among the syllables, vowel duration would be longest when preceding the voiced aspirate [gh]. Coda voicing, and thus, vowel duration, have been shown to correlate negatively to vowel F1 in English and Arabic [Wolf, J. Phonetics 6, 299–309 (1978); de Jong and Zawaydeh ibid, 30, 53–75 (2002)]. It is not known whether vowel F1 depends directly on coda voicing, or is determined indirectly via duration. Since voicing and aspiration both increase duration, F1 measurements of this data set (which will be presented) may answer that question.
Subglottal coupling and vowel space
Authors: Chi Xuemin , Sonderegger Morgan
Published: September 2013

A model of acoustic coupling between the oral and subglottal cavities predicts discontinuities in vowel formant prominences near resonances of the subglottal system. One discontinuity occurs near 1300–1500 Hz, suggesting the hypothesis that this is a quantal effect [K. N. Stevens, J. Phonetics 17, 3–46 (1989)] dividing speakers’ front and back vowels. Recordings of English vowels (in /hVd/ environments) for several male and female speakers were made, while an accelerometer attached to the neck area was used to capture the subglottal waveform. Statistics on our subglottal resonance measurements are given and compared with prior work. Qualitative agreement is shown between the resonator model and diphthong data with time-varying F2 for several speakers. Comparison of the second vowel formant and second subglottal formant tracks across all speakers, analysis of the formant spaces spanned by each speaker’s vowel data, and a survey of vowel formant data for a sample of the world’s languages support the possibility that a speaker’s second subglottal resonance divides front and back vowels. Possible implications for theories of vowel inventory structure [e.g., J. Lijencrants and B. Lindblom, Language 48, 839–862 (1972)] are discussed. [Work supported by NIH Grant DC00075.]
Spectral specification of articulatory parameters
Authors: Iskarous Khalil
Published: September 2013

It has long been known that there is no unique analytic solution to the inverse problem in speech. However, for any problem with multiple solutions, a unique solution can still be obtained by optimizing some function on the set of possible solutions. Several investigators have done just that for the speech problem. In this work, we return to the analytic approach to ask two questions. First, despite the fact that the spectral frequencies do not uniquely specify the area function, what about articulation do they specify and what additional information is necessary for unique specification? Second, if such information were available, what is the form of the function that specifies the area function given all the necessary spectral information? Based on theorems from network synthesis it is known that the zeros or formant amplitudes can provide the extra information. Assuming that the poles and zeros of the driving point impedance are given (sidestepping the difficulty of obtaining these parameters from a speech signal), a functional relation is presented that uniquely specifies articulatory information given acoustic information. The relation between this method and pole-residue methods will also be discussed. [Work supported by NIH Grant DC-02717.]
Influence of Mandarin tone exposure on the processing of intonation by 14-year-old American adolescents: An fMRI study
Authors: Lin Jo-Fu Lotus , Imada Toshiaki , Kuhl Patricia , Wang Yue
Published: September 2013

This study investigated, for American adolescents, whether the learning of non-native speech contrasts in one prosodic domain (Mandarin Chinese tones) would influence the processing of non-native contrasts in another prosodic domain (Mandarin Chinese intonation). Two groups of 14-year-old American teenagers were tested using the functional magnetic resonance imaging (fMRI) technique, including eight who had received a two-week Mandarin tone training program and eight with no exposure to Mandarin. Subjects were scanned during identification tasks. Despite their similar behavioral performance on identification of Mandarin intonation, preliminary results showed different cortical activation patterns for the two groups. Teenagers exposed to Mandarin showed similar activation patterns for the Mandarin intonation and Mandarin tone task, with more right-hemisphere activation for intonation, which differed from activation for English intonation. Teenagers without exposure activated similar areas for Mandarin and English intonation. Familiarity with Mandarin tonal contrasts affects brain activation, not only for Mandarin tones but also for Mandarin intonation, suggesting that training effects may transcend levels. [Work supported by NIH (HD 37954) and the Talaris Research Institute.]
Predicting the intelligibility of deaf children’s speech from acoustic measures
Authors: Uchanski Rosalie M. , Geers Ann E. , Brenner Christine M. , Tobey Emily A.
Published: September 2013

A weighted combination of speech-acoustic measures may provide an objective assessment of speech intelligibility in deaf children that could be used to evaluate the benefits of sensory aids and rehabilitation programs. This investigation compared the accuracy of two different approaches, multiple linear regression and a simple neural net. These two methods were applied to identical sets of acoustic measures, including both segmental (e.g., voice-onset times of plosives, spectral moments of fricatives, second formant frequencies of vowels) and suprasegmental measures (e.g., sentence duration, number and frequency of intersentence pauses). These independent variables were obtained from digitized recordings of deaf children’s imitations of 11 simple sentences. The dependent measure was the percentage of spoken words from the 36 McGarr Sentences understood by groups of naive listeners. The two predictive methods were trained on speech measures obtained from 123 out of 164 8- and 9-year-old deaf children who used cochlear implants. Then, predictions were obtained using speech measures from the remaining 41 children. Preliminary results indicate that multiple linear regression is a better predictor of intelligibility than the neural net, accounting for 79% as opposed to 65% of the variance in the data. [Work supported by NIH.]
Interferometry and computer-aided tomography as an acoustic analysis tool
Authors: Wyber Ron J. , Ferguson Brian G.
Published: September 2013

By using a wide band signal to measure the impulse response of a target it is generally possible to resolve the reflected signal into a sequence of impulses associated with discrete scattering features or structural waves. If two hydrophones, with an appropriate vertical separation, are used to receive the signal from a target, it is possible to determine the vertical position of the source for each impulse in the sequence from the relative phase of the analytic signal received at each of the hydrophones. The amplitude and phase information measured as the target rotates can then be used to form a three-dimensional image in which the position of the strong scattering sources is highlighted. Examples are given showing how the images formed provide information allowing features in the measured impulse response to be related to different scattering mechanisms such as specular target highlights, multiple reflections or structural waves. By characterizing the acoustic hotspots in the image in this way it is possible to provide feedback to the designer of a stealth target quantifying the contribution of individual features on the target to the overall target strength.
Investigations into the application of a new sonar system for assessing fish passage in Alaskan rivers
Authors: Burwen Deborah , Maxwell Suzanne , Pfisterer Carl
Published: September 2013

Over a two-year period (2002–2003) the Alaska Department of Fish and Game (ADFG) has evaluated a relatively new sonar technology at several sites in Alaska to determine its applicability to counting migrating fish in rivers. The new system, called a dual frequency identification sonar (DIDSON), is a high-definition imaging sonar designed and manufactured by the University of Washingtons Applied Physics Lab for military applications such as diver detection and underwater mine identification. Studies conducted in 2002 in a clearwater stream with high fish passage rates (5000 fish/hour) demonstrated that the DIDSON could provide accurate estimates of fish migrating upstream in rivers. Additional studies conducted in 2002 with live tethered fish indicated that size information could be derived from the cameralike images produced by the DIDSON system at ranges up to 12 m. In 2003, ADFG deployed DIDSON systems to assess fish passage in five Alaskan rivers. In each river, the DIDSON system was deployed in the side-looking configuration typically used in riverine sonar applications for estimating fish passage. Preliminary results from experiments in both 2002 and 2003 indicate that the DIDSON provides significant improvements in our ability to detect, track, and determine the direction of travel of migrating fish in rivers.
Imaging flaws in thin multilayered metal sheets using an array of guided mode transducers
Authors: Fisher Karl A.
Published: September 2013

In a multilayered elastic structure, acoustic energy can be focused into a particular layer by identifying a suitable guided wave mode. Once this guided mode is identified, low profile surface mounted interdigital transducers can be designed to excite preferentially this mode in the multilayered elastic structure. This has led to the development of a novel eight-channel linear array based on guided mode interdigital transducers. The array has been used to generate data for a time domain reconstruction algorithm. Resulting images reveal 1–2-mm length cracks in the center layer of a 300-μm-thick composite steel plate.
Source localization and inversion in the presence of internal waves
Authors: Baer Ralph N. , Collins Michael D.
Published: September 2013

It is often possible to localize an acoustic source in a medium with environmental uncertainties by including environmental parameters in the search space [J. Acoust. Soc. Am. 90, 1410–1422 (1991)]. This approach has recently been applied to problems involving stochastic environmental parameters [J. Acoust. Soc. Am. 114, 2401 (2003)]. The parameters of the Garrett–Munk spectrum were held fixed, and the source was localized by generating replica fields for various realizations of the internal wave field. In the present work, source localization simulations are performed with the parameters of the Garrett–Munk spectrum included in the parameter space. The possibility of solving an inverse problem to estimate the internal wave parameters is also considered. [Work supported by the ONR.]
Sea surface effects on reverberation vertical coherence and inverted bottom acoustic parameters in the East China Sea
Authors: Zhou Ji-Xun , Zhang Xue-Zhen , Dahl Peter H. , Simmen Jeffrey A.
Published: September 2013

Wideband reverberation measurements were repeatedly conducted at the center of the ASAEX site in the East China Sea, on 3 and 5 June, 2001. Between these two measurement days, wind speed and rms wave height changed significantly, going from about 1 m/s and 0.1 m to 10 m/s and 0.35 m, respectively. This paper will compare reverberation vertical coherence (RVC) and RVC-inverted equivalent bottom acoustic parameters in frequency range of 100–1200 Hz for the two measurements [J. X. Zhou and X. Z. Zhang, J. Acoust. Soc. Am. 113, 2204 (2003)]. The difference of equivalent bottom reflection losses, obtained from two measurements, is well explained by the supporting sea surface data. The results show that an inversion of seabottom acoustic parameters from shallow-water long-range reverberation (or sound propagation) should take the surface condition into account, especially for higher sea states and higher frequencies. [Work supported by ONR and NNSF of China.]
Engaging spaces: Intimate electro-acoustic display in alternative performance venues
Authors: Bahn Curtis , Moore Stephan
Published: September 2013

In past presentations to the ASA, we have described the design and construction of four generations of unique spherical speakers (multichannel, outward-radiating geodesic speaker arrays) and Sensor-Speaker-Arrays, (SenSAs: combinations of various sensor devices with outward-radiating multichannel speaker arrays). This presentation will detail the ways in which arrays of these speakers have been employed in alternative performance venues—providing presence and intimacy in the performance of electro-acoustic chamber music and sound installation, while engaging natural and unique acoustical qualities of various locations. We will present documentation of the use of multichannel sonic diffusion arrays in small clubs, ‘‘black-box’’ theaters, planetariums, and art galleries.
The role of infrasounds in maintaining whale herds
Authors: Payne Roger S.
Published: September 2013

For whales and dolphins a basic social unit is the herd. In several species, herds have been observed to maintain the same speed, direction, and membership overnight, and while swimming in waters of near-zero visibility—evidence that individuals can stay together using nonvisual cues. The most likely such cue is sound. If whale herds are held together with sound, yet we define herds as groups of whales seen moving together, then we are using visual criteria to judge what is an acoustic phenomenon, and our conclusions about a most basic unit of cetacean social structure, the herd, are at least incomplete, and, quite possibly, worthless. By calling herds, heards, we remind ourselves that sound controls herd size. We then consider that some whale infrasound can propagate across deep water at useful intensities (even in today’s ship-noise-polluted ocean) for thousands of kilometers. The distance to which blue and fin whale sounds propagate before falling below background noise is given, and the possible advantages these whales obtain from such sounds is explored. The conclusion is that by sharing information on food finds infrasonically, fin and blue whales may have developed a way to divide up the food resources of an entire ocean.
Do manatees utilize infrasonic communication or detection?
Authors: Gerstein Edmund , Gerstein Laura , Forsythe Steve , Blue Joseph
Published: September 2013

Some researchers speculate Sirenians might utilize infrasonic communication like their distant elephant cousins; however, audiogram measurements and calibrated manatee vocalizations do not support this contention. A comprehensive series of hearing tests conducted with West Indian manatees yielded the first and most definitive audiogram for any Sirenian. The manatee hearing tests were also the first controlled underwater infrasonic psychometric tests with any marine mammal. Auditory thresholds were measured from 0.4 to 46 kHz, but detection thresholds of possible vibrotactile origin were measured as low as 0.015 kHz. Manatees have short hairs on their bodies that may be sensitive vibrotactile receptors capable of detecting particle displacement in the near field. To detect these signals the manatee rotated on axis, exposing the densest portion of hairs toward the projector. Manatees inhabit shallow water where particle motion detection may be more useful near the water’s surface, where sound pressures are low due to the Lloyd mirror effect. With respect to intraspecific communication, no infrasonic spectra have been identified in hundreds of calibrated calls. Low source levels and propagation limits in shallow-water habitats suggest low-frequency manatee calls have limited utility over long distances and infrasonic communication is not an attribute shared with elephants.
Interactive patterns of vocal communication in African elephant herds (Loxodonta africana)
Authors: O’Connell-Rodwell Caitlin E. , Wyman Megan T. , Hart Lynette A. , Redfield Shay
Published: September 2013

This study examines the interactive nature of vocalizations produced within African elephant herds during waterhole visits at Etosha National Park, Namibia. The temporal organization and physical characteristics of 1025 vocalizations, documented within 14.8 h of acoustic field recordings, were analyzed using a variety of statistical tests. Temporal distribution analyses indicated that calls were clumped in time (Kologorov–Smirnov, average significant p=0.00158) and the majority of the calls occurred after herds began the process of departing a waterhole (Wilcoxon signed rank, p=0.0012). In addition, 84% of all calls began within 30 s of another call. Based on the analysis of the temporal patterning of calls, a conversational series of vocalizations was defined as calls separated by less than 30 s of silence. The majority of calls in a conversational series are overlapping or contiguous, indicating that multiple elephants are involved in the exchange. A variety of physical characteristics (duration, frequency, frequency modulation, and frequency at peak amplitude) was compared across three different call types. These conversational call patterns may function to maintain intragroup cohesion and coordination as well as intergroup resource sharing and competition reduction. [Work supported by: Namibia Nature Foundation, Etosha Ecological Institute, UC Davis Block, Jastro Shields, and Faculty Research Grants.]
Anatomy of infrasonic communication in baleen whales: Divergent mechanisms of sound generation in mysticetes and odontocetes
Authors: Reidenberg Joy S. , Laitman Jeffrey T.
Published: September 2013

Cetaceans produce sounds at opposite ends of the frequency spectrum. The laryngeal role in odontocete sound production (echolocation, communication) remains unclear. Mysticete infrasonics are presumed to be laryngeal in origin, but production mechanisms are unknown. To address this, we examined postmortem larynges in 6 mysticete species (3 genera) and compared them to our odontocete collection (20 species/15 genera). Results indicate that the rostral portion of the odontocete larynx is elongated, narrow, rigid, and normally positioned intranarially. This portion of the mysticete larynx is comparatively shortened, open, pliable, and in Megaptera may be retracted from its intranarial position. Internally, mysticete vocal folds are thick, paired, and oriented horizontally, compared with the thin, usually unpaired, and vertically oriented odontocete fold. Mysticetes may generate low frequency sounds via pneumatically driven fold vibrations, which then pass to attached laryngeal sac walls, through overlying throat pleats, to water. Rorqual mysticetes may also vibrate paired corniculate flaps while regulating airflow into the nasal region. Infrasonic pulses may pass through adjacent soft palate, skull, or nasal cartilages to water. Laryngeal anatomy in mysticetes and odontocetes appears highly divergent. These morphological differences may correlate to adaptations for producing infrasonic (mysticete) or ultrasonic (odontocete) communication. [Work supported by ONR:N00014-96-1-0764, ONR:N00014-99-1-0815, and AMNHSOF.]
Multifrequency analyses of fish distributions in the northwest Atlantic
Authors: Jech J. Michael
Published: September 2013

Routine acoustical surveys for estimating Atlantic herring (Clupea harengus) population abundance have been conducted on Georges Bank during the autumn spawning season from 1998 to present. Acoustical data are collected with a Simrad EK500 scientific echo sounder operating at 12 or 18, 38, and 120 kHz, and split-beam (the 12-kHz system is a single beam) transducers. Biological measurements and verification of acoustical scatterers are obtained with a pelagic trawl. Acoustical data are evaluated (scrutinized) manually to remove noise, faulty bottom detections, and to classify acoustical backscattering to species. Species classification is currently subjective, and is based on the experience of the scientists and trawl catches. Objective species classification and automated fish density and abundance estimates are an obvious goal for fisheries surveys using advanced technologies. Classification methods using relationships among frequency-dependent volume backscattering strengths, such as presence–absence and combination–permutation, are described and presented. Results indicate that while classification using these methods and acoustical information alone is not robust, these methods highlight backscattering patterns within aggregations and have the potential to characterize backscattering patterns observed in fisheries acoustics data. [Work supported by NOAA Fisheries and ONR.]