bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection and representation of rhythm and tempo II: The modulation spectrogram
Authors: Todd Neil P. M.
Published: October 2013

In the paper a second algorithm is presented for the computation of a primitive representation of rhythmic and temporal structure [N. P. Todd, C. S. Lee, and D. J. O’Boyle, J. New Mus. Res. 28, 5–28 (1999)]. The algorithm consists of the following stages: (1) cochlear filtering, by means of an ear model based on the gammatone filter-bank, (2) modulation filtering, by means of a constant-Q band-pass modulation filter-bank; (3) peak detection and sensorimotor filtering; (4) feedforward control of a simple plant to simulate tapping. The output of the modulation filter-bank produces a representation in the form of a modulation spectrogram whereby any periodic input gives rise to a harmonic series. Metrical structure may be inferred from the harmonic structure of the spectrum with the addition of a learning and recognition mechanism. This algorithm may account for a number of additional phenomena including the approximate Weber law property of tempo sensitivity, adaptation to perturbations in the period or phase and the autocorrelation statistics of sensorimotor synchronization. The performance of the algorithm is evaluated by comparison with the tapping behavior of 20 human subjects to the 48 fugue subjects from the Well-Tempered Clavier by J. S. Bach.
Use of tile overlays to reduce the radiation efficiency of radiating surfaces
Authors: Koopmann Gary , Salesky Eric , Chen Weicheng
Published: October 2013

An intriguing possibility for reducing the radiation efficiency of a structure is to overlay its radiating surfaces with a contiguous set of low mass tiles. Experimental results show that significant reductions in sound power are possible depending on number of tiles, their geometry, attachment methods, mass, stiffness, and the amount of shear damping used to connect their edges to one another. This paper presents results of a combined theoretical and experimental study performed on a clamped, flat plate driven at its center and with nearly infinite baffle boundary conditions. Tiles are overlayed on the surface of the plate and lightly attached with a polymer material. A scanning laser vibrometer is used to examine the vibration patterns of the plate and the corresponding tiles for several different tile configurations over a frequency range 20–1000 Hz. Results indicate that sound power reductions occur when the independent response of each tile combines to produce an overall volume velocity that is lower than that of the plate by itself over the frequency range of interest.
In-line quincke tube muffler
Authors: Patrick William P. , Bryant Rebecca S. , Greenwald Larry E.
Published: October 2013

A unique low-pressure-drop muffler is described which has been designed to attenuate low frequency tonal noise in ducts. Flow through the muffler is divided into two noncommunicating paths in the cylindrical configuration which was designed, built, and tested. Half of the flow is ducted through a straight central annulus and the other half is ducted through a partitioned outer annulus which directs the flow in a spiral flow pattern around the inner annulus. Thus the outer flow has a longer path length and the sound within the outer annulus is phase-delayed relative to the inner flow causing destructive interference between the inner and outer waves with resulting strong attenuation at the tuned frequencies. A procedure will be described for designing a muffler (with flow) to produce high attenuation at the fundamental noise tone and all harmonics (up to the first cross mode). Results will be presented which show that the muffler achieved over 20 dB attenuation for the first five harmonics of the incident noise in a flowing duct.
Jet noise from ultrahigh bypass turbofan engines
Authors: Posey Joe W. , Norum Thomas D. , Brown Martha C. , Bhat Thonse R. S.
Published: October 2013

Modern commercial jet transport aircraft are powered by turbofan engines. Thrust from a turbofan engine is derived in part from the exhaust of a ducted fan, which may or may not be mixed with the core exhaust before exiting the nacelle. The historical trend has been toward ever higher bypass ratios (BPRs). The BPR is the ratio of air mass passing through the fan to that going through the core. The higher BPR engines can be more efficient and quieter. In general, a higher BPR results in lower average exhaust velocities and less jet noise. In order to address a scarcity of noise data for BPRs greater than 6, an extensive database collection effort was undertaken using the Jet Engine Simulator in NASA Langley’s Low Speed Aeroacoustic Wind Tunnel. Forward flight simulations of Mach 0.1, 0.2, and 0.28 were used with BPRs of 5, 8, 11, and 14. Data was taken over the entire operating line of the simulated engines along with parametric deviations to provide a complete set of sensitivity measurements. The results will be used to develop an empirical jet noise prediction capability for ultrahigh bypass engines.
Numerical model for multi-mode active control of turbofan noise
Authors: Ireland Laralee G. , Sommerfeldt Scott D.
Published: October 2013

A numerical model has been developed to investigate the possibility of implementing active control to minimize noise radiation from turbofan engines. Previous experimental work on the NASA Glenn Research Center ANC fan have been encouraging, but the question remains of whether the modal approaches investigated can be expected to work effectively on real engines. The engine model presented here uses an indirect boundary element method, implemented with Sysnoise, and a multi-mode Newton algorithm to simulate the active control. Experimental results obtained using the NASA Glenn ANC fan, which has a simplified cylindrical engine geometry, were used as a benchmark for the model. The model results have been found to compare well with the experimental results. Recently, a more realistic, but still axisymmetric, engine geometry has been used. Preliminary results will be presented which indicate that a modal ANC approach should still be effective for controlling turbofan noise.
Word recognition and phonetic structure acquisition: Possible relations
Authors: Morgan James
Published: October 2013

Several accounts of possible relations between the emergence of the mental lexicon and acquisition of native language phonological structure have been propounded. In one view, acquisition of word meanings guides infants’ attention toward those contrasts that are linguistically significant in their language. In the opposing view, native language phonological categories may be acquired from statistical patterns of input speech, prior to and independent of learning at the lexical level. Here, a more interactive account will be presented, in which phonological structure is modeled as emerging consequentially from the self-organization of perceptual space underlying word recognition. A key prediction of this model is that early native language phonological categories will be highly context specific. Data bearing on this prediction will be presented which provide clues to the nature of infants’ statistical analysis of input.
Language discrimination without language: Experiments on tamarin monkeys
Authors: Tincoff Ruth , Hauser Marc , Spaepen Geertrui , Tsao Fritz , Mehler Jacques
Published: October 2013

Human newborns can discriminate spoken languages differing on prosodic characteristics such as the timing of rhythmic units [T. Nazzi et al., JEP:HPP 24, 756–766 (1998)]. Cotton-top tamarins have also demonstrated a similar ability to discriminate a morae- (Japanese) vs a stress-timed (Dutch) language [F. Ramus et al., Science 288, 349–351 (2000)]. The finding that tamarins succeed in this task when either natural or synthesized utterances are played in a forward direction, but fail on backward utterances which disrupt the rhythmic cues, suggests that sensitivity to language rhythm may rely on general processes of the primate auditory system. However, the rhythm hypothesis also predicts that tamarins would fail to discriminate languages from the same rhythm class, such as English and Dutch. To assess the robustness of this ability, tamarins were tested on a different-rhythm-class distinction, Polish vs Japanese, and a new same-rhythm-class distinction, English vs Dutch. The stimuli were natural forward utterances produced by multiple speakers. As predicted by the rhythm hypothesis, tamarins discriminated between Polish and Japanese, but not English and Dutch. These findings strengthen the claim that discriminating the rhythmic cues of language does not require mechanisms specialized for human speech. [Work supported by NSF.]
Infants long-term memory for complex music
Authors: Ilari Beatriz , Polka Linda , Costa-Giomi Eugenia
Published: October 2013

In this study we examined infants’ long-term memory for two complex pieces of music. A group of thirty 7.5 month-old infants was exposed daily to one short piano piece (i.e., either the Prelude or the Forlane by Maurice Ravel) for ten consecutive days. Following the 10-day exposure period there was a two-week retention period in which no exposure to the piece occurred. After the retention period, infants were tested on the Headturn Preference Procedure. At test, 8 different excerpts of the familiar piece were mixed with 8 different foil excerpts of the unfamiliar one. Infants showed a significant preference for the familiar piece of music. A control group of fifteen nonexposed infants was also tested and showed no preferences for either piece of music. These results suggest that infants in the exposure group retained the familiar music in their long-term memory. This was demonstrated by their ability to discriminate between the different excerpts of both the familiar and the unfamiliar pieces of music, and by their preference for the familiar piece. Confirming previous findings (Jusczyk and Hohne, 1993; Saffran et al., 2000), in this study we suggest that infants can retain complex pieces of music in their long-term memory for two weeks.
Application of a model of the auditory primal sketch to cross-linguistic differences in speech rhythm: Implications for the acquisition and recognition of speech
Authors: Todd Neil P. M. , Lee Christopher S.
Published: October 2013

It has long been noted that the world’s languages vary considerably in their rhythmic organization. Different languages seem to privilege different phonological units as their basic rhythmic unit, and there is now a large body of evidence that such differences have important consequences for crucial aspects of language acquisition and processing. The most fundamental finding is that the rhythmic structure of a language strongly influences the process of spoken-word recognition. This finding, together with evidence that infants are sensitive from birth to rhythmic differences between languages, and exploit rhythmic cues to segmentation at an earlier developmental stage than other cues prompted the claim that rhythm is the key which allows infants to begin building a lexicon and then go on to acquire syntax. It is therefore of interest to determine how differences in rhythmic organization arise at the acoustic/auditory level. In this paper, it is shown how an auditory model of the primitive representation of sound provides just such an account of rhythmic differences. Its performance is evaluated on a data set of French and English sentences and compared with the results yielded by the phonetic accounts of Frank Ramus and his colleagues and Esther Grabe and her colleagues.
Depth averaged acoustic field variability—its relationship to sound speed field variability—comparison of s
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m95 data to PE calculations
Authors: Mignerey Peter , Orr Marshall
Published: October 2013

Depth and time averaged acoustic signal energy was found to change by about 3 db over a 2.3 day period during an experiment on the New Jersey Shelf (swarm95). The sound speed field along the 42 km propagation path has been reconstructed by integrating point CTD and range continuous acoustic flow visualization data taken during four transects of the acoustic propagation path. Sound speed fields were constructed for each transect. Depth averaged acoustic signal energy calculated for each of the sound speed fields are compared to the measured depth averaged acoustic signal energies.
Lung damage from exposure to low-frequency underwater sound
Authors: Dalecki Diane , Child Sally Z. , Raeman Carol H.
Published: October 2013

The effects of low-frequency (∼100−2500 Hz) underwater sound are most pronounced in and near tissues that contain resonant gas bodies. The response of gas bodies in vivo (such as the lung and intestine) to low-frequency underwater sound was characterized through a series of investigations. A specially designed acoustic exposure system, capable of generating maximum acoustic fields of ∼200 dB re: 1 microPa over the 100–2500 Hz frequency range, was implemented for these investigations. Acoustic scattering techniques were used to characterize the response of gas bodies to underwater sound exposure and to determine the resonance frequency of murine lungs. Lung damage was observed in mice exposed to underwater sound at the resonance frequency of their lung. The extent of tissue damage to the lung (and surrounding tissues such as the liver) increased with increasing pressure amplitude. Damage to lung tissue correlated with acoustic pressure amplitude and not acoustic particle velocity. Similar investigations were performed with murine intestinal gas in vivo.
Forgotten acousticians
Authors: Beyer Robert T.
Published: October 2013

In the French edition of his book on acoustics (1807), Ernest Chladni cited the work of many acousticians in or before his time. The names of Bernoulli, Biot, D’Alembert, Euler, and Laplace are familiar to us all, but Kircher, Lambert, Monro, Perolle, Riccati, Scarpa, and Mathew Young are far less so. This paper will recall the work of these individuals and others, and the contributions they made to early work on sound.
Acoustic measurements for nanoscale test instruments
Authors: Daugela Antanas
Published: October 2013

Acoustic methods have been used successfully for microscale contact nondestructive evaluation, but until very recently, were not available for the nanometer scale. Noncontact submicrometer resolution ultrasonic microscopy and scanning probe microscopy (SPM) operate at higher acoustic modes and have great potential to be qualitative but face data interpretation difficulties. Nanomechanical test instruments offer nanometer scale quantitative characterization. These tools coupled with in situ SPM-type imaging and simultaneous acoustic response monitoring open new instrumentation horizons for micro/nano fracture mechanics. Both active and passive acoustic methods can be utilized to characterize a large variety of substrates and coatings. Examples of AE monitoring of nanoindentation/scratch on data storage media will be presented. Plastic deformation induced events can be separated from contact friction events by identifying AE signatures. Active ultrasonic methods can be utilized for nanoscale characterization of tribological surfaces. A friction coefficient reduction of 20% was observed on an ultrasonically excited surface during nanoscratch testing and was further investigated using post-scratch SPM-type imaging. A synergy of localized ultrasonic monitoring and nanoindentation technique can lead to the development of new and promising instrumentation for characterizing in vivo/vitro biological tissues at the molecular level. Examples on evaluating ultrasonically transmitted signal through biological samples will be discussed.
Using a combined localization/detection model to simulate human localization performance near the masked detection threshold level
Authors: Braasch Jonas
Published: October 2013

Recently, the perceptual lateralization of a partly masked target has been successfully simulated using the interaural cross-correlation difference (ICCD) model [Braasch, J. Acoust. Soc. Am. 108, 2597 (2000)]. However, in the accompanying listening tests, the target level was often found to be below the masked detection threshold level. To improve the model performance, a detection threshold model has been implemented in the localization model so that the localization process is triggered only when the target level is above a threshold. Otherwise, the position of the sound source is determined according to a behavioral pattern. The detection stage is based on an on- and offset detection algorithm that analyzes the derivative in time. For the simulation of the binaural conditions, the equalization-cancellation algorithm of Durlach [J. Acoust. Soc. Am. 35, 1206–1218 (1963)] has been included in the model. It has been shown that for target levels above the masked detection threshold, the on-/offset detection algorithm is accurate enough to trigger the subtraction process of the ICCD algorithm. Furthermore, the improved model has resulted in better simulations of human localization patterns in the presence of a distracting sound.
FM phase and the continuity illusion
Authors: Carlyon Robert P. , Micheyl Christophe , Deeks John M. , Moore Brian C. J.
Published: October 2013

In experiment 1 subjects discriminated between a ‘‘regular’’ 1-kHz FM tone and one where the FM phase reversed midway through, at a zero crossing of the modulator waveform. Zero-peak FM depth was 100 Hz. Performance was near-perfect when the modulator frequency was 2.5 Hz, but declined sharply as it increased above 10 Hz. This is consistent with instantaneous frequency being smoothed over a finite time window, and with the phase reversal producing a ‘‘bump’’ in the window output, which decreases for faster modulations. In experiment 2 listeners discriminated between an FM tone containing a phase reversal and one where the FM depth of one-half modulator cycle was increased by various amounts (‘‘df’’)—thereby also producing a bump in the window output. Performance reached a minimum (at df= approx 5%), consistent with the theory. Finally, a 200-ms gap was inserted at the phase reversal point in a 5-Hz FM stimulus, removing subjects’ ability to detect a phase reversal. Filling the gap with noise introduced a sensation of continuity, but subjects could not detect a phase reversal, even though this would have been easy in a physically continuous stimulus. Results suggest that FM phase is not encoded explicitly in the auditory system.
Least-mean-square estimation of new equal-loudness level contours from recent data based on a loudness perception model
Authors: Suzuki Yôiti , Takeshima Hisashi
Published: October 2013

Since probable large errors were suggested in 1985 in the equal-loudness level contours by Robinson and Dadson [Br. J. Appl. Phys. 7, 166–181 (1956)], which were standardized as ISO 226, a considerable amount of data on the equal-loudness relation has been accumulated. Most of the data consistently show a large discrepancy up to more than 20 phons from the contours, especially below 1 kHz. To obtain reliable contours from these new data sporadically given for some specific frequencies and phons, a model function representing the equal-loudness relation was derived from a loudness function modified by the two-stage loudness perception model. Values of the parameters of the model function were obtained by fitting the function to the experimental data. Equal-loudness level contours could be drawn by use of the model function with the parameter values interpolated along the frequency axis. The resultant equal-loudness level contours showed clear differences from those by Robinson and Dadson for all loudness levels over the whole frequency range, particularly in the frequency range lower than 1 kHz. In contrast, the contours rather resemble those given by Fletcher and Munson in 1933 and by Churcher and King in 1937 in the midfrequency range at relatively low loudness levels. [Work supported by NEDO.]
Effects of signal duration and temporal position on physiological measures of the growth of masking
Authors: Liu Jiayun , Clock Eddins Ann
Published: October 2013

Psychoacoustic studies have shown that the growth of masking for pure-tone signals in broadband noise is linear when the signal onset is delayed relative to the masker but is nonlinear when signal and masker onsets are synchronous [e.g., Strickland (2001)]. Curiously, for very short duration signals (10 ms), nonlinear effects have been observed for some delayed-onset conditions (Oxenham et al., 1997). While nonlinear effects may result from peripheral compression, it is unclear if other physiological mechanisms might be responsible for the influence of signal temporal parameters on the growth of masking. To address this issue, the growth of masking was studied using evoked-potential responses recorded from the chinchilla inferior colliculus (IC). Quiet and masked thresholds were obtained for 1.0-, 4.0-, and 6.5-kHz signals as a function of signal duration (2–100 ms) and temporal position (delayed or nondelayed) within a 400-ms broadband noise masker. Masker spectrum levels ranged from −10 to 20 dB. Consistent with Stricklands data, physiological growth of masking was linear under delayed conditions and nonlinear under nondelayed conditions. Specifically, for nondelayed conditions, the degree of nonlinearity was greatest for high-frequency signals but did not vary with signal duration. [Work supported by NSF IBN-9996379.]
Auto-bicoherence and cross-bicoherence of the transverse vibration signals of cracked Bernoulli–Euler beams
Authors: Linehan Daniel
Published: October 2013

The transverse vibration of a cracked Bernoulli–Euler beam is nonlinear if the crack does not remain open. Because this nonlinearity is even-ordered, an examination of the third-order frequency domain statistics (auto-bicoherence and cross-bicoherence) of the forcing input and acceleration output time histories should reveal quadratic nonlinearities in the form of modal interactions. To this end, the transverse vibration behavior of unconstrained, cracked Bernoulli–Euler beams was studied at the University of Texas at Austin Applied Research Laboratories. The beams were made of an aluminum 6061 alloy and were cracked with varying depths at either the midpoint or off-center. The auto-bicoherence and cross-bicoherence of both a finite-element model (FEM) and experimental beams will be discussed. The excitation was both band-limited noise and narrow-band forcing at one end of the beams. While the FEM results show a crude relationship between crack depth and modal interaction when excited with band-limited noise, the experimental results only show such a relationship when the excitation is narrow-band. The results do not demonstrate a clear method of determining the crack location. Further studies should be conducted with more discrete crack depths and different narrow-band force excitation. [Work supported by Univ. of Texas, Austin Applied Research Laboratories IR&D Program.]
A silicon nitride microphone diaphragm inspired by the ears of the parasitoid fly Ormia ochracea
Authors: Miles Ronald N. , Gibbons Colum , Gao Jia , Yoo Kyutae , Su Quang , Cui Weili
Published: October 2013

A differential microphone is described that has been designed to employ similar operating principles to that of the ears of the parasitoid fly, Ormia ochracea. The ears of this fly have been shown to be highly directional even though they are only about 1 mm across [R. N. Miles, D. Robert, and R. R. Hoy, J. Acoust. Soc. Am. 98, 3059–3070 (1995)]. Analyses of the mechanics of this biological system suggest novel approaches to the design of miniature directional microphones. Finite element analysis results for the acoustic resonse of a 1 mm by 2 mm silicon nitride microphone diaphragm are presented. The diaphragm responds to pressure gradients in a manner that is inspired by Ormia’s ears. Predicted results for the natural frequencies, mode shapes, frequency response and directivity of our design are shown to compare closely with measured data obtained for a prototype silicon nitride diaphragm. [Work supported by NIH and DARPA.]
Modeling and direct visualization of temperature rise induced by high-intensity ultrasound in tissue
Authors: Khokhlova Vera , Miller Nathan , Ollos Ryan , Martin Roy , Bailey Michael , Mohammadian Yahya , Naghavi M.
Published: October 2013

High-intensity focused ultrasound (HIFU) creates localized heating deep in tissues which can be used to necrose tumors or cauterize vessels. Imaging of the temperature field in tissue is important for guiding HIFU treatment. Temperature rise in excised and degassed bovine liver exposed to high-intensity focused ultrasound was visualized experimentally and simulated numerically. An infrared camera, which records surface temperature only, was used to measure spatial temperature distribution. Two blocks of tissue were stacked, and their interface was placed along the axis of the ultrasound beam. A single element concave transducer (2 MHz, 35-mm aperture, 51-mm radius of curvature) was used. After exposure to ultrasound, the upper piece was immediately removed, and the temperature on the axial plane was infrared imaged. The absorption coefficient of liver was measured and then used for numerical simulations. The theoretical model employs a KZK-type equation for the acoustic pressure field combined with a bioheat equation. It is shown that experiment and theory agree well on the location, shape, and dimensions of the heated region. The dependence of absorption coefficient in liver on exposure to ultrasound, to air, and to degassing process was studied. [Work supported by NIH Fogarty, NSF, and CRDF.]
Energy: Converting from acoustic to biological resource units
Authors: Benoit-Bird Kelly J. , Au Whitlow W. L.
Published: October 2013

Acoustic backscattering strength is often used as an index of biomass; however, the relationship has not been directly validated. Relationships were investigated between acoustic cross section at 200 kHz and measured values of length, biovolume, dry weight, ash-free dry weight, and caloric content of the same individual specimens. Animals were part of the Hawaiian mesopelagic boundary community and included shrimps, squids, and myctophid fishes. The strong linear relationships found between all the variables measured make it possible to approximate any one variable from the measured values of others within a class of animals. These data show that for these midwater animals, acoustic scattering can be used as an index of biomass. Dorsal-aspect acoustic cross section at 200 kHz predicted dry weight and ash-free dry weight at least as well as did body length, a standard predictor. Dorsal-aspect acoustic cross section at 200 kHz was also a strong predictor of total caloric content. The relationships between dorsal-aspect acoustic cross section and both weight and caloric content of Hawaiian mesopelagic animals were linear and additive. Consequently, it is possible to directly convert acoustic energy from these animals to organic resource units without having knowledge of the size distribution of the populations being studied.
Validation of an auralization system
Authors: Christensen Claus Lynge , Weitze Christoffer A. , Rindel Jens Holger , Gade Anders Christian
Published: October 2013

The room acoustics program odeon provides auralization using fully filtered binaural room impulse responses, each reflection being filtered through nine octave bands and a set of head-related transfer functions. Using the full filtering scheme allows, in principle, a complete audible presentation of all the properties, time-variant frequency coloration, as well as directional information predicted by the room acoustics program. Two methods of verification have been applied. The first method is based on direct measurements on the impulse responses predicted by odeon, using the room acoustics measuring system dirac in order to verify that the auralization method is actually capable of reproducing the predicted room acoustic parameters. Monaural auralization filters were used for this purpose. The other method is an audible comparison between in situ recordings of a singing person in real rooms and the odeon auralization of the same situations. The latter verification is part of an ongoing European research project, CAHRISMA, on restoration of the acoustics in old Byzantine churches and mosques in Istanbul.
Acoustic properties of bovine cancellous bone from 0.5 to 1.5 MHz
Authors: Lee Kang Il , Roh Heui-Seol , Yoon S. W.
Published: October 2013

Most previous studies using ultrasound for the diagnosis of osteoporosis have employed ultrasound in the frequency range from 0.2 to 1 MHz. Acoustic properties of 14 defatted bovine cancellous bone specimens were investigated in vitro. Speed of sound (SOS) and broadband ultrasonic attenuation (BUA) were measured using two matched pairs of transducers with the center frequencies of 1 and 2.25 MHz, respectively, in order to cover a broad frequency range from 0.5 to 1.5 MHz. In this frequency range, SOS and BUA show significant linear positive correlations with apparent bone density. These results suggest that the frequency range from 0.5 to 1.5 MHz may also be useful in the diagnosis of osteoporosis. [Work supported by BK21 Program, KRF (KRF-2000-015-DP0718), and KOSEF (KOSEF-2000-0238-100) in Korea.] a)For (Biomedical Ultrasound/Bioresponse to Vibration) Best Student Paper Award.
Analysis of surface wave formation over a grating surface with bounded beams
Authors: Zhu Wenhao
Published: October 2013

It had been demonstrated previously that homogeneous plane waves could not excite effective surface wave over periodic surface structures at low frequencies. In this work, acoustic surface wave over a periodic surface is predicted under limited source incidence (e.g., Gaussian beam). A comblike grating surface is considered in the analysis, for which a theoretical model for predicting the scattered fields has been developed. Numerical results on scattered surface wave as well as bulk waves are given for different parameters of the incident beam. It is found that at low frequencies (ka≪1, where a is the grating period and k is the wave number in air), it is the inhomogeneity of the source that results in surface wave propagation in the scattered waves. The analysis is also applicable to impedance grating structures.
A spherical microphone array for spatial sound recording
Authors: Meyer Jens , Elko Gary W.
Published: October 2013

The progression of audio from monophonic to the present day 5-channel playback is being driven by the desire to improve the immersion of the listener into the acoustic scene. In the limit, the goal is the reconstruction of the original sound field. This talk describes the decomposition of the sound field into orthogonal components, the so-called spherical harmonics and is directly related to the method of Ambisonics. These components contain all required information to allow a reconstruction of the original sound field. This approach is scalable to any number of loudspeakers and is also backwards compatible to surround sound, stereo and mono playback. One problem is the recording of the orthogonal components. So far only solutions exist that allow the recording of spherical harmonics up to first order. This limits the spatial resolution. This presentation introduces a new microphone that overcomes this limitation. It consists of pressure sensors that are equally distributed on the surface of a rigid sphere. The number of sensors depends on the highest order spherical harmonic to be recorded. A minimum of (n+1)2 sensors is required to record harmonics up to nth order. The sensor signals are then processed to give the desired spherical harmonic outputs.
Chaos, catastrophe, and critical frequency points on elastic shells
Authors: Werby Michael , Uberall H.
Published: October 2013

Exact equations exist for the determination of the backscattered signals excited by acoustic signals on submerged elastic shells. In the absence of resonances these signals may be cast in terms of conservation principles of inertial components of the interaction of the signal with the object. This indeed leads to an adequate description of the acoustic background of such targets. What is determined to be critical is the inclusion of an entrained mass related to the displacement of the mass equivalent of the fluid due to the movement of the object. But what happens to such inertial effects in the presence of elastic resonances? We explore this issue and demonstrate that the effective or inertial component ranges from zero to infinity over a small frequency range that characterizes the resonance width. Over this range there is also a phase shift of 1800. We may as well examine the effect of radiation loading in this range. It is also possible to investigate a phase plot of the real and imaginary components of the effective mass factor which leads to closed trajectories for certain classes of resonances and to hyperbolic trajectories for other types. The meaning of these observations is discussed. [Work supported by NRL and ONR.]
Sound duration as a perceptual cue influencing vocal behavior of male bullfrogs
Authors: Simmons Andrea M.
Published: October 2013

Female frogs of several species use the temporal cue of sound duration to aid in mate choice. Little is known, however, about the sensitivity of male frogs to this cue. Male bullfrogs emit a complex advertisement call to attract females for mating, and to announce territory occupation to other males. In two experiments, the sensitivity of vocalizing male bullfrogs to field playbacks of advertisement calls differing in duration was examined. The number and latency of evoked vocal responses to the stimuli was used as a measure of perception. Males responded with fewer calls, at longer latencies, to stimuli shorter in duration than the standard signal (with a duration at the mean value for the species). Males preferred stimuli longer in duration than the standard signal, responding with more calls at shorter latencies. They did not, however, significantly lengthen their own calls in response to playbacks of long duration signals. This preference for ‘‘supernormal’’ stimuli may be an important factor mediating the evolution of communication signals. [Work supported by NIH.]
Beam intensity striations and applications
Authors: Yang T. C.
Published: October 2013

Modal interferences, or striations, are analyzed and modeled for the beam outputs of a horizontal line array obtained by conventional beamforming. The enhancement of signal levels by the array gain (over that of a single element) makes the measurement of the invariant parameter more reliable even in the weak signal cases. It is shown that the signal beams exhibit the same striation pattern as that predicted (theoretically) for a single element. Specifically, for a broadside signal, the beam striation is identical to that of the single element plus a constant signal gain. For a non-broadside target, the signal beam intensity will be modified by a frequency-bearing dependent signal gain due to the signal spread over multiple beams (the multipath effect). Nonetheless the signal beam intensity still retains the same striation pattern (slope) as for a single element. At non-signal look directions, the sidelobe beams (those outside the canonical cones containing the signal arrivals) exhibit an entirely different striation pattern. The difference of signal striations between a fast range-rate, close range signal and distant, slow range-rate interferences can be used to suppress the interferences in array processing. [Work supported by ONR.]
Acoustic granular materials with pore size distribution close to log-normal
Authors: Horoshenkov Kirill , Swift Mark
Published: October 2013

The water suction method is used to determine the parameters of the pore size distribution of a representative selection of loose and consolidated granular materials. It is shown that the experimentally determined pore size distribution in granular materials is often close to log-normal. The low- and high-frequency asymptotic behavior of the Biot viscosity correction function for media with log-normal pore size distribution is investigated and used to develop a simple rational approximation. This approximation is used to predict accurately the acoustic characteristic impedance and propagation constant for this class of materials. Unlike many available theoretical models for the acoustic properties of porous media which involve empirical shape factors, the proposed approximation is based entirely on four routinely measurable nonacoustic parameters: the porosity, flow resistivity, tortuosity, and the standard deviation of the pore size. The theoretical predictions for the acoustic surface impedance and absorption coefficient of loose and consolidated granulates are compared against the experimental results. A good agreement is obtained throughout the considered frequency range. [The authors are grateful to the Engineering and Physical Sciences Research Council (EPSRC) in the UK (Grant GR/L54905) for the support of this work. The authors would like to thank Dr. P. Leclaire for his help with the water suction experiments.]
Using the Speech Transmission Index to predict the intelligibility of non-native speech
Authors: van Wijngaarden Sander J. , Steeneken Herman J. M. , Houtgast Tammo , Bronkhorst Adelbert W.
Published: October 2013

The calibration of the Speech Transmission Index (STI) is based on native speech, presented to native listeners. This means that the STI predicts speech intelligibility under the implicit assumption of fully native communication. In order to assess effects of both non-native production and non-native perception of speech, the intelligibility of short sentences was measured in various non-native scenarios, as a function of speech-to-noise ratio. Since each speech-to-noise ratio is associated with a unique STI value, this establishes the relation between sentence intelligibility and STI. The difference between native and non-native intelligibility as a function of STI was used to calculate a correction function for the STI for each separate non-native scenario. This correction function was applied to the STI ranges corresponding to certain intelligibility categories (bad–excellent). Depending on the proficiency of non-native talkers and listeners, the category boundaries were found to differ from the standard (native) boundaries by STI values up to 0.30 (on the standard 0–1 scale). The corrections needed for non-native listeners are greater than for non-native talkers with a similar level of proficiency. For some categories of non-native communicators, the qualification excellent requires an STI higher than 1.00, and therefore cannot be reached.
Machine musicianship
Authors: Rowe Robert
Published: October 2013

The training of musicians begins by teaching basic musical concepts, a collection of knowledge commonly known as musicianship. Computer programs designed to implement musical skills (e.g., to make sense of what they hear, perform music expressively, or compose convincing pieces) can similarly benefit from access to a fundamental level of musicianship. Recent research in music cognition, artificial intelligence, and music theory has produced a repertoire of techniques that can make the behavior of computer programs more musical. Many of these were presented in a recently published book/CD-ROM entitled Machine Musicianship. For use in interactive music systems, we are interested in those which are fast enough to run in real time and that need only make reference to the material as it appears in sequence. This talk will review several applications that are able to identify the tonal center of musical material during performance. Beyond this specific task, the design of real-time algorithmic listening through the concurrent operation of several connected analyzers is examined. The presentation includes discussion of a library of C++ objects that can be combined to perform interactive listening and a demonstration of their capability.
New anisotropic perfectly matched layer boundary condition for elastic waves in solids
Authors: Zheng Yibing , Huang Xiaojun , Apfel Robert E.
Published: October 2013

The perfectly matched layer (PML) is currently a popular absorbing boundary condition for numerical modeling of electromagnetic, acoustic, and elastic wave problems. Existing PML formulation for elastic waves uses a field splitting scheme, which increases the number of variables in the computation. The new anisotropic elastic wave PML modifies the elasticity or compliance tensors to be anisotropic. It utilizes fewer variables for both isotropic and anisotropic media, so that computing memory and time can be reduced significantly. Its formulations for Cartesian and curvilinear coordinate systems will be discussed. Moreover, this anisotropic PML can be directly used in the finite element method, and easily be implemented in the finite difference time domain method as well. [Work supported by NASA (NAG3-2147) and by NSF (CTS-9870015).]
Animal models of speech sound categorization
Authors: Lotto Andrew J.
Published: October 2013

Several recent studies have examined phonetic category formation by training nonhuman animals (e.g., birds) to respond differentially to distributions of speech sounds. Animal models provide good tests of theories of perceptual category formation because one can completely control the input distributions and obtain a fine-grained sampling of responses to the stimulus space. In studies using vowel sound distributions, animals’ response structures reveal two salient characteristics. First, there is a tendency to respond most strongly to stimuli that are furthest from the boundaries between training distributions. Second, there is evidence that the structure of responses is a function of the statistics of the training input. This can be seen as a peak in response for stimuli near the centroid of the input distribution. These same response structure characteristics can also be seen in data collected from humans in categorization tasks. It is possible that these two characteristics are indicative of two systems of learning: one functional and one statistical. A similar dichotomy has also been recently proposed in the visual categorization literature. The implications of these results for theoretical and computational models of phonetic acquisition will be discussed. [Work supported by NSF and NIH.]
Subjective assessment of listening environments in classrooms
Authors: Hodgson Murray , Kennedy Susan
Published: October 2013

A questionnaire was developed to evaluate subjective perception of the listening environment by university classroom users. The questionnaire was administered to over 5700 students in 30 randomly selected classrooms. The questionnaire recorded students’ perceptions of the listening environment and possible modifying factors. A ‘‘perception of listening ease’’ (PLE) score was generated. Items most associated with a poor listening environment were noise from other students and intermittent noises outside the classroom. Over 50% of students reported frequent difficulty with hearing questions from other students. Poorer PLE score was associated with high background noise from students, an instructor who articulates poorly, poorer classroom lighting and ‘‘room air,’’ microphone use, and decreased room volume per student. In large classrooms, hearing-impaired students scored PLE lower. Results indicate that PLE is a reliable and valid measure of classroom users’ subjective perceptions of the listening environment, and that optimal classroom acoustical design needs to take into consideration ‘‘in-use’’ conditions, as well as physical characteristics of the empty classroom.
Identification of Genetic Variants That Affect Histone Modifications in Human Cells
Authors: McVicker Graham , van de Geijn Bryce , Degner Jacob F. , Cain Carolyn E. , Banovich Nicholas E. , Raj Anil , Lewellen Noah , Myrthil Marsha , Gilad Yoav , Pritchard Jonathan K.
Published: October 2013

DNA Differences

The extent to which genetic variation affects an individual's phenotype has been difficult to predict because the majority of variation lies outside the coding regions of genes. Now, three studies examine the extent to which genetic variation affects the chromatin of individuals with diverse ancestry and genetic variation (see the Perspective byFurey and Sethupathy).Kasowskiet al.(p.750, published online 17 October) examined how genetic variation affects differences in chromatin states and their correlation to histone modifications, as well as more general DNA binding factors.Kilpinenet al.(p.744, published online 17 October) document how genetic variation is linked to allelic specificity in transcription factor binding, histone modifications, and transcription.McVickeret al.(p.747, published online 17 October) identified how quantitative trait loci affect histone modifications in Yoruban individuals and established which specific transcription factors affect such modifications.
Extensive Variation in Chromatin States Across Humans
Authors: Kasowski Maya , Kyriazopoulou-Panagiotopoulou Sofia , Grubert Fabian , Zaugg Judith B. , Kundaje Anshul , Liu Yuling , Boyle Alan P. , Zhang Qiangfeng Cliff , Zakharia Fouad , Spacek Damek V. , Li Jingjing , Xie Dan , Olarerin-George Anthony , Steinmetz Lars M. , Hogenesch John B. , Kellis Manolis , Batzoglou Serafim , Snyder Michael
Published: October 2013

DNA Differences

The extent to which genetic variation affects an individual's phenotype has been difficult to predict because the majority of variation lies outside the coding regions of genes. Now, three studies examine the extent to which genetic variation affects the chromatin of individuals with diverse ancestry and genetic variation (see the Perspective by

Furey and Sethupathy

).

Kasowski
et al.

(p.
750
, published online 17 October) examined how genetic variation affects differences in chromatin states and their correlation to histone modifications, as well as more general DNA binding factors.

Kilpinen
et al.

(p.
744
, published online 17 October) document how genetic variation is linked to allelic specificity in transcription factor binding, histone modifications, and transcription.

McVicker
et al.

(p.
747
, published online 17 October) identified how quantitative trait loci affect histone modifications in Yoruban individuals and established which specific transcription factors affect such modifications.
Draft Genome Sequences of Pseudomonas aeruginosa B3 Strains Isolated from a Cystic Fibrosis Patient Undergoing Antibiotic Chemotherapy
Authors: Marvig Rasmus Lykke , Jochumsen Nicholas , Johansen Helle Krogh , Høiby Niels , Molin Søren , Sommer Morten O. , Jelsbak Lars , Folkesson Anders
Published: October 2013

Pseudomonas aeruginosa
frequently establishes chronic infections in the airways of patients suffering from cystic fibrosis (CF). Here, we report the draft genome sequences of four
P. aeruginosa
B3 strains isolated from a chronically infected CF patient undergoing antibiotic chemotherapy.
Draft Genome Sequences of Burkholderia cenocepacia ET12 Lineage Strains K56-2 and BC7
Authors: Varga John J. , Losada Liliana , Zelazny Adrian M. , Kim Maria , McCorrison Jamison , Brinkac Lauren , Sampaio Elizabeth P. , Greenberg David E. , Singh Indresh , Heiner Cheryl , Ashby Meredith , Nierman William C. , Holland Steven M. , Goldberg Joanna B.
Published: October 2013

The
Burkholderia cepacia
complex (BCC) is a group of closely related bacteria that are responsible for respiratory infections in immunocompromised humans, most notably those with cystic fibrosis (CF). We report the genome sequences for
Burkholderia cenocepacia
ET12 lineage CF isolates K56-2 and BC7.