bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging the shear flow of complex fluids using high-frequency ultrasound
Authors: Manneville Sébastien , Bécu Lydiane , Colin Annie , Tanter Mickaël , Fink Mathias
Published: September 2013

Complex fluids show fascinating properties under flow due to the existence of a mesoscopic scale located between the microscopic and the macroscopic scales. For instance, uncoiling of polymer molecules under flow leads to well-documented shear-thinning behaviors. More surprisingly, inhomogeneous flows of visco-elastic fluids are observed in simple shear experiments even at very low Reynolds numbers. Indeed, due to strong coupling between the flow and the fluid microstructure, shear may induce new structural organizations that coexist in the flow leading to shear localization or to shear bands. Whereas classical rheology only yields global data such as the viscosity averaged over the whole sample, the present work is devoted to local ultrasonic velocimetry in sheared complex fluids. A 1D high-frequency (36 MHz) speckle tracking technique is presented that allows the spatio-temporal study of various inhomogeneous unsteady flows. Moreover, preliminary results using a 2D ultrafast flow imaging technique at 12 MHz show that images of the flow can be obtained with an unprecedented temporal resolution.
Breast tissue characterization with high-frequency scanning acoustic microscopy
Authors: Kumon R. E. , Bruno I. , Heartwell B. , Maeva E.
Published: September 2013

We have performed imaging of breast tissue using scanning acoustic microscopy (SAM) in the range of 25–50 MHz with the goal of accurately and rapidly determining the structure and composition throughout the volume of the samples. In contrast to traditional histological slides, SAM images can be obtained without special preparation, sometimes even without sectioning, but with sufficiently high spatial resolution to give information comparable to surface optical images. As a result, the use of high-frequency SAM at the time of breast lumpectomy to identify disease-free margins has the potential to reduce reoperative rates, patient anxiety, and local recurrence. However, only limited work has been performed to characterize breast tissue in the frequency range above clinical ultrasound devices. The samples are 4-cm2-thick sections (2–3 mm) taken from mastectomies and preserved in formalin. They are placed between two plates and immersed in water during imaging. Attenuation images are acquired by focusing the acoustic beam at the top and bottom of the samples, although better results were obtained for bottom focusing. For purposes of comparison and identification of histological features, acoustical images will be presented along with optical images obtained from the same samples. [Work supported by CIHR.]
Design and testing of an annular array for very-high-frequency imaging
Authors: Ketterling Jeffrey A. , Ramachandran Sarayu , Lizzi Frederic L. , Aristizábal Orlando , Turnbull Daniel H.
Published: September 2013

Very-high-frequency ultrasound (VHFU) transducer technology is currently experiencing a great deal of interest. Traditionally, researchers have used single-element transducers which achieve exceptional lateral image resolution although at a very limited depth of field. A 5-ring focused annular array, a transducer geometry that permits an increased depth of field via electronic focusing, has been constructed. The transducer is fabricated with a PVDF membrane and a copper-clad Kapton film with an annular array pattern. The PVDF is bonded to the Kapton film and pressed into a spherically curved shape. The back side of the transducer is then filled with epoxy. One side of the PVDF is metallized with gold, forming the ground plane of the transducer. The array elements are accessed electrically via copper traces formed on the Kapton film. The annular array consists of 5 equal-area rings with an outer diameter of 1 cm and a radius of curvature of 9 mm. A wire reflector target was used to test the imaging capability of the transducer by acquiring B-scan data for each transmit/receive pair. A synthetic aperture approach was then used to reconstruct the image and demonstrate the enhanced depth of field capabilities of the transducer.
A new hearing protector rating: The Noise Reduction Statistic for use with A weighting (NRSA).
Authors: Berger Elliott H. , Gauger Dan
Published: September 2013

An important question to ask in regard to hearing protection devices (HPDs) is how much hearing protection they can provide. With respect to the law, at least, this question was answered in 1979 when the U. S. Environmental Protection Agency (EPA) promulgated a labeling regulation specifying a Noise Reduction Rating (NRR) measured in decibels (dB). In the intervening 25 years many concerns have arisen over this regulation. Currently the EPA is considering proposing a revised rule. This report examines the relevant issues in order to provide recommendations for new ratings and a new method of obtaining the test data. The conclusion is that a Noise Reduction Statistic for use with A weighting (NRSA), an A–A’ rating computed in a manner that considers both intersubject and interspectrum variation in protection, yields sufficient precision. Two such statistics ought to be specified on the primary package label—the smaller one to indicate the protection that is possible for most users to exceed, and a larger one such that the range between the two numbers conveys to the user the uncertainty in protection provided. Guidance on how to employ these numbers, and a suggestion for an additional, more precise, graphically oriented rating to be provided on a secondary label, are also included.
Real-world performance of hearing protection systems in Army aviation
Authors: Ahroon William A. , Robinette Martin B.
Published: September 2013

Methods to measure the performance of hearing protective devices using naive subjects were developed to better estimate the hearing protection that can be reasonably achieved in operational environments. A ‘‘preference’’ for subject-fit methods over experimenter-fit or experimenter-supervised-fit methods has been growing among many hearing conservation professionals but has not received universal acceptance. The real-world performance of hearing protection used in Army aviation was measured. Army aviators who had completed 38 weeks of rotary-wing aircraft training were used in personal hearing protector evaluations using ANSI S12.6 real-ear attenuation at threshold procedures. Using their own flight helmets (group 1) or helmets and earplugs (group 2), the aviators were instructed to fit their helmet or helmets with earplugs as they do for flight operations (i.e., an informed-user fit). Following this evaluation, an experimenter-supervised fit evaluation was performed, which included helmet and earplug fit by a technician trained and experienced in helmet fit procedures. For both groups, the real-ear attenuation at threshold results for the informed-user and experimenter-supervised fitting procedures were virtually identical. Thus, the experimenter-supervised fit procedure (ANSI S12.6-1997 Method A) is appropriate for evaluating the performance of personal hearing protective headgear in the Army aviation environments.
An acoustic streaming instability within regenerator-based thermoacoustic devices
Authors: So Jin H. , Swift Gregory W. , Backhaus Scott
Published: September 2013

As traveling-wave thermoacoustic devices are scaled to higher power, the cross-sectional areas of their regenerators increase proportionally in order to maintain a thermodynamic optimum. Unfortunately, this allows the possibility of a spatially dependent acoustic streaming instability internal to their regenerators due to weak thermal and hydrodynamic communication transverse to the acoustic axis. Calculations show one possible result is two regions of opposed streaming forming a recirculating acoustic streaming cell similar to a convection cell. If the streaming is vigorous enough, it can transport enthalpy between heat exchangers at different temperatures, reducing the efficiency of the thermoacoustic device. An experimental apparatus is being used to search for this instability. A summary of the theory and results from the experimental search will be presented. [Work supported by DOE’s Office of Science.]
Amplitude modulation detection with cochlear implants: Effects of electrode separation and stimulus level
Authors: Sarampalis Anastasios , Chatterjee Monita
Published: September 2013

Amplitude modulation (AM) detection performance has been studied in the past with normal-hearing and hearing-impaired populations. The temporal modulation transfer function (TMTF) is a plot of AM detection performance as a function of modulation rate and provides a way of characterizing temporal sensitivity. Typically the TMTF takes the form of a low-pass filter, with performance declining above 50–70-Hz modulation rate. TMTFs have also been measured with cochlear implant patients, showing a similar low-pass characteristic, with a cutoff around 140-Hz rate, while sensitivity to AM was found to increase with increasing current level. The present study investigated the effects of stimulation level and electrode separation on TMTFs with cochlear implant patients. TMTFs were measured for narrow through wide electrode separations and three different (loudness-balanced) percentages of the dynamic range. Preliminary results indicate that sensitivity increases (lower thresholds) with increasing stimulation level, for a given electrode separation. However, comparing TMTFs across different electrode separations, sensitivity is independent of current level, but increases as a function of percentage of dynamic range. In summary, it appears that AM detection performance with cochlear implants depends primarily on sensation level, rather than current level or electrode separation. [Work supported by NIDCD Grant No. R01DC04786.]
Fractal EEG analysis with Higuchi’s algorithm of low-frequency noise exposition on humans
Authors: Panuszka Ryszard , Damijan Zbigniew , Kasprzak Cezary
Published: September 2013

Authors used methods based on fractal analysis of EEG signal to assess the influence of low-frequency sound field on the human brain electro-potentials. The relations between LFN (low-frequency noise) and change in fractal dimension EEG signal were measured with stimulations tones. Three types of LFN stimuli were presented; each specified dominant frequency and sound-pressure levels (7 Hz at 120 dB, 18 Hz at 120 dB, and 40 Hz at 110 dB). Standard EEG signal was recorded before, during, and after subject’s exposure for 35 min. LFN. Applied to the analysis fractal dimension of EEG-signal Higuchis algorithm. Experiments show LFN influence on complexity of EEG-signal with calculated Higuchi’s algorithm. Observed increase of mean value of Higuchi’s fractal dimension during exposition to LFN.
Low pitches of frequency-transposed stimuli: Salience estimates from a full population-interval model
Authors: Cariani Peter
Published: September 2013

Transposed stimuli consisting of half-wave rectified modulators of high frequency carriers allow comparisons of pitch perception across frequency regions. While listeners can discriminate low F0-pitches of simple transposed stimuli (1 Fm-Fc), most cannot detect low pitches of complex transposed stimuli [Fm=300, 400, 500 Hz, Fc=4, 6.35, 10.08 kHz; Oxenham et al., PNAS (2004)]. Auditory nerve (AN) responses to a low-frequency harmonic complex (F0=100 Hz;n=3–5) and its transposition were simulated using filtering (middle ear, 48 gammatone filters, 144 fibers, human CF distribution, 100 Hz to 18 kHz), rectification, adaptive gain control, spontaneous activity (three classes), 65 dB SPL simulated level. Pitch salience was estimated by analyzing population-interval histograms using subharmonic interval sieves. The harmonic complex produced high salience (2.05), well above assumed pitch detection threshold (∼1.3). Simple transposed stimuli produced lower saliences (1–1.37). Some were below threshold, inconsistent with psychophysical pitch discrimination results. The complex transposed stimulus produced an F0-salience (1.31) near threshold, qualitatively consistent with their mixed detection results. Dramatic differences are thus seen between low-frequency and transposed stimuli. Clearly, for these and other high-frequency stimuli, full AN population-interval models can produce salience estimates that differ substantially from simple intuitions and/or partial implementations. Interpretational caution is therefore counseled.
An equivalent transform method for evaluating the effect of water column mismatch on geoacoustic inversion
Authors: Lin Ying-Tsong , Chen Chi-Fang , Lynch James F.
Published: September 2013

An equivalent transform method for evaluating the effect of water column mismatch on geoacoustic inversion is presented. This quantitative method is derived from perturbative inverse formulations and gives a quantitative way to evaluate how the water column mismatch error transfers into the bottom inversion results. In this paper, this method is illustrated with two test cases, in which linear and nonlinear internal waves are considered as the cause of the water column mismatch, respectively. In the first case, the range-averaged geoacoustic inversion errors due to the water column mismatch are largely eliminated after a full cycle of the linear internal wave, and the error pattern repeats with the period of the internal wave. However, in the second case, the errors are accumulated but scaled down with increasing range. Additionally, ignoring the lower-frequency components of the signal removes its corresponding contribution from the overall errors, and reduces the bottom depth influenced by water column mismatch.
Blending vocal music with a given sound field due to the characteristics of the running autocorrelation function of singing voices
Authors: Kato Kosuke , Fujii Kenji , Kawai Keiji , Ando Yoichi , Yano Takashi
Published: September 2013

This is a study to meet music and the opera house acoustics. It is said that singers adjust their interpretation style according to the acoustical condition of the sound field in a room. However, this mechanism of blending of musical performance with the sound field is unknown. In order to obtain a method of performance blending of opera house acoustics, we attempted to develop evaluation criteria for a singing voice in terms of the minimum value of the effective duration of the running autocorrelation function (r-ACF), (te)min, of sound source signals. This temporal factor has shown to have close correlation with the subjective response of both listeners and performers to sound fields [Y. Ando, Architectural Acoustics (AIP Press/Springer-Verlag, New York, 1998)]. As example for the control of (te)min due to performing style, effects of singing style, kind of vowel, relative pitch, vibrato extent, and intonation on the values of (te)min are demonstrated. In addition, the fine structure of the r-ACF is discussed with regard to the identification of vowels of singing voice. a)Now at 1-10-27 Yamanokami, Kumamoto, Japan.
Cavitation detection during and following HIFU exposure in vitro
Authors: Coussios Constantin-C. , Farny Caleb H. , Thomas Charles R. , Cleveland Robin O. , Holt R. Glynn , Roy Ronald A.
Published: September 2013

Is the existence of a sustained hyperechogenic region on B-scan images following HIFU treatment a necessary and sufficient condition for cavitation to have occurred during HIFU exposure? Three means of cavitation monitoring were used synchronously, before, during, and after continuous-wave HIFU exposure of an agar-graphite tissue phantom. A 1.1-MHz HIFU transducer was confocally aligned with a 15-MHz passive cavitation detection (PCD) transducer and a 5-MHz scan head. The HIFU pressure amplitude was increased in steps of 0.26 MPa every 5 s. A peak detector recorded the peak PCD signal level and a dynamic signal analyzer monitored broadband noise emissions (5–10 MHz). The sudden onset of a PCD output signal occurred at a peak-negative focal pressure of 1.25 MPa; no post-HIFU hyperechogenic region was visible on the B-scan images. A hyperechogenic region did eventually appear, but only for focal pressures in excess of 1.8 MPa. Inertial cavitation can therefore occur during HIFU exposure in the absence of a post-HIFU hyperechogenic region. The focal pressure for which such a region is observed can be as much as 50% higher than the threshold pressure for inertial cavitation inception. [Work supported by the ASA and the NSF Center for Subsurface Sensing and Imaging Systems.]
Fluorescent real-time monitoring of HIFU cardiac focal ablation
Authors: Qu Fujian , Nikolski Vladimir , Efimov Igor , Deng Cheri
Published: September 2013

To study HIFU cardiac ablation, florescent imaging was used to monitor in real time the electrophysiology changes of cardiac tissues during focal HIFU ablation. We applied HIFU ablation of AV nodal and ventricular preparations of Langendorff-perfused rabbit heart while monitoring electrical activity in real-time. HIFU energy was applied to ablate the AV node and ventricular tissue of Langendorff-perfused rabbit hearts while monitoring electrical activity in real-time with fluorescent voltage-sensitive dye imaging and surface electrodes. HIFU was generated using a spherical piezoelectric ceramics transducer (diameter 42 mm, F-number 1.2) at 4.23 MHz. When HIFU was applied to ventricular epicardium fluorescent imaging it revealed gradual reduction of the plateau phase and amplitude of the action potential. Subsequently conduction block and cell death were observed at the site of ablation. In our study HIFU produced focal lesions of 0.2–0.8 mm for 10–60-s applications. When HIFU was applied to the AV node, fluorescent imaging and electrograms revealed the development of the AV block.
Calculation of impulse responses with a cellular automata algorithm
Authors: Barjau Ana
Published: September 2013

The air columns in musical instruments usually have a predominant dimension and thus are very often modeled as 1D systems where uniparametric waves propagate. Different algorithms can be found in the literature to simulate this propagation. The more widely used are finite difference schemes and delay lines. A finite difference scheme (FD) is a numerical integration of a differential formulation (the wave equation), while delay lines (DL) use analytical exact solutions of the wave equation over finite lengths. A new and different approach is that of a cellular automaton (CA) scheme. The underlying philosophy is opposite those of FD and DL, as the starting point is not the wave equation. In a CA approach, the phenomenon to be studied is reduced to a few simple physical laws that are applied to a set of cells representing the physical system (in the present case, the propagation medium). In this paper, a CA will be proposed to obtain the impulse response of different bore geometries. The results will be compared to those obtained with other algorithms.
New paradigms for musical control—A decade of development at the MIT Media Lab
Authors: Paradiso Joseph A.
Published: September 2013

As electronic musical instruments liberate the action and energy of control from physical sound production, they are free to mutate into many different forms—the constraints on instrument design have shifted from physics to ergonomics, applications, and aesthetics. Low-cost sensors enable stimuli of all types to act as input, and with a computer interposed between action and sound production, essentially any sonic or musical dynamic can be mapped onto any gesture or activity with an increasingly high degree of interpretation or ‘‘mapping,’’ Accordingly, the notion of a musical instrument is being redefined, and as possibilities broaden, some researchers and artists are striving to break boundaries while others work to quantify and understand expanded metrics for musical interaction. Over the past decade, the author and his colleagues have adapted a wealth of sensor technologies and developed many interaction paradigms to scratch away at the evolving frontier of electronic musical instruments [J. Paradiso, ‘‘Electronic music interfaces: new ways to play,’’ IEEE Spectrum 34(12), 18–30 (1997)]. This presentation will review the status of electronic music controllers, provide a snapshot of current issues that the field is facing, and present various examples of new musical interfaces developed at the MIT Media Lab.
Relationships of loudness, level, and time structure in pipe organ registrations and design
Authors: Bray Wade
Published: September 2013

Time-dependent loudnesses and sound pressure levels were measured binaurally from a variety of individual stops and multi-stop registrations of several classical and theater pipe organs covering a wide range of sizes, tonal designs, pipe scalings, wind pressures, and spatial relationships. Studies were also made of modulation in individual low-frequency notes, and in notes and chords affected by the presence or absence of tremulants. Timbres of certain solo stops were assessed in terms of the relationship of specific loudness and sound pressure spectra to their importance in creating subjective timbre. In addition to loudness and sound pressure measurement, advanced analysis by a hearing model (Sottek) and a temporal/tonal pattern-measurement algorithm (‘‘relative approach’’) were employed. Significant differences in the relationship of loudness and level were found depending principally on tonal design, pipe scaling and wind pressures on one hand, and octave-related tonal centers and timbral characteristics of individual stops on the other hand. Consideration was also given to the subjective spatial soundscape resulting from different pipe organ physical layouts and from simultaneous registrations between or among physically-separated speaking divisions.
Context sensitive road traffic noise impact mapping—Taking the neighborhood soundscape into account
Authors: Klboe Ronny , Engelien Erik , Steinnes Margrete
Published: September 2013

Road traffic noise exposure contour maps are difficult to interpret by nonexperts who are familiar with neither the road traffic noise exposure measures nor their associated impacts. An alternative is to map impacts such as annoyance. However, in urban areas the noise impacts are multi-factorially determined and context sensitive. In particular people become more annoyed by a given noise level at the most exposed facade of their dwelling when their neighborhood soundscape is even noisier. A two-tiered approach makes use of contextual soundscape information in determining noise impacts and builds contiguous neighborhood sonoscapes delimiting neighborhood areas with similar noise impacts. Neighborhood sonoscape maps facilitate a more precise targeting of local noise abatement measures, and can illustrate the impacts of noise abatement measures. With appropriate classification and class labels neighborhood sonoscapes provide an environmental labeling of the expected perceived sound quality of the neighborhood for consumers, the public and planners. Neighborhood sonoscape maps may be utilized for national stratification and subsequent two-stage cluster sampling of the population. The advantage of this approach is that focused traffic counts, extended sound modeling and monitoring of noise abatement procedures, population composition, etc. can be undertaken for a limited representative set of neighborhood sonoscapes.
Nondestructive evaluation of multilayered structures using ultrasonic guided waves generated by an electromagnetic acoustic array transducer
Authors: Quarry Michael
Published: September 2013

Multilayered structures with adhesively bonded plates are a common inspection problem for nondestructive evaluation. In many cases, large areas must be inspected with limited access. One powerful method for inspecting these structures is to excite ultrasonic guided wave modes that propagate over distances of many meters and into inaccessible areas that may be embedded within another structure. The utilization of guided wave modes with horizontal shear displacement for the nondestructive evaluation of adhesively bonded plates is studied here. Modes were excited in the frequency region of 200 to 800 kHz by an electromagnetic acoustic array transducer with half-inch and quarter-inch spacing. Samples were constructed for testing that included mutlilayered plates as well as multilayered structures with a transition between a single layer plate and a multilayer plate. Notches of various sizes were placed in the bottom layer to simulate cracks and test sensitivity. Experimental data shows that an electromagnetic acoustic array was able to generate a dominant horizontal shear mode to detect the notches with sufficient signal to noise for practical inspection by tuning the frequency of excitation. Notches of 10% through-wall were detected.
Binaural release from informational masking: Results from a speech identification task
Authors: Gallun Frederick J. , Mason Christine R. , Kidd Gerald
Published: September 2013

This study examined how binaural cues can reduce informational masking (IM) in a speech identification task. Target and masker sentences were processed into non-overlapping frequency bands, thus limiting ‘‘energetic masking,’’ and were presented over headphones. Listeners identified key words in the target sentence. In a baseline condition, target and masker were presented monotically (SmMm), producing large amounts of IM. Binaural release from IM (i.e., improved performance re. SmMm) was observed when the target was presented monotically and the masker diotically (SmM0), suggesting that the shift of masker image away from target led to the reduction in IM. Creating large interaural differences in level (ILDs) showed that for a monaural target, binaural release, though related to ILD, occurred even when the masker image should have been lateralized at the target ear. For differences in time (ITDs) up to 600 μsec, the amount of binaural release was completely independent of ITD. For a diotic target and binaural masker, however, release only occurred for large ITDs or ILDs. These results suggest that for monaural targets and binaural maskers, IM in a speech task can be reduced through a binaural cue that is present across the entire range of biologically plausible ITDs and ILDs.
Auditory stream segregation with multi-tonal complexes in hearing-impaired listeners
Authors: Rogers Deanna S. , Lentz Jennifer J.
Published: September 2013

The ability to segregate sounds into different streams was investigated in normally hearing and hearing-impaired listeners. Fusion and fission boundaries were measured using 6-tone complexes with tones equally spaced in log frequency. An ABA–ABA- sequence was used in which A represents a multitone complex ranging from either 250–1000 Hz (low-frequency region) or 1000–4000 Hz (high-frequency region). B also represents a multitone complex with same log spacing as A. Multitonal complexes were 100 ms in duration with 20-ms ramps, and- represents a silent interval of 100 ms. To measure the fusion boundary, the first tone of the B stimulus was either 375 Hz (low) or 1500 Hz (high) and shifted downward in frequency with each progressive ABA triplet until the listener pressed a button indicating that a ‘‘galloping’’ rhythm was heard. When measuring the fusion boundary, the first tone of the B stimulus was 252 or 1030 Hz and shifted upward with each triplet. Listeners then pressed a button when the ‘‘galloping rhythm ended.’’ Data suggest that hearing-impaired subjects have different fission and fusion boundaries than normal-hearing listeners. These data will be discussed in terms of both peripheral and central factors.
Temporal streaming based on fine structure cues
Authors: Grimault Nicolas
Published: September 2013

Alternating sequence of two A and B bursts of sound tends to be perceptually organized in different auditory streams when introducing either a spectral or a temporal difference between A and B. In general, the channeling theory of streaming predicts that any salient difference between the excitation patterns evoked by A and B sounds would lead to a segregated percept. Some previous studies have, however, evidenced that a sequence of sounds with similar spectral properties but with different temporal properties can be heard as segregated. In particular, temporal cues are probably responsible for the segregated percept when hearing a sequence of bursts of noises that are amplitude-modulated at different rates. All previous streaming experiments involved stimuli that had frequency components below 5000 Hz. As a consequence, the individual contribution of temporal fine structure cues and envelope cues could not be dissociated and remains largely undetermined. The current experiment is dedicated to test further the relative importance of both envelope and fine structure cues to segregate sequences of unresolved complex tones with different fundamental frequencies. Two high-frequency regions above and below 5000 Hz and several phase relationships leading to several temporal peak factors have been used in a subjective streaming task.
Distributed versus concentrated load distribution for a shell subject to a rotating constant load
Authors: Pierucci Mauro , Rosen Scott
Published: September 2013

When a beam or a shell is forced by a concentrated load at a discrete frequency, the structure response is composed of the sum of its natural modes. The concentrated load is always approximated by a point load as represented by the Dirac delta function. If the point load is replaced by a constant magnitude-distributed load with the same integrated value, the importance of the different modes is a function of the width of the loading function. Results will be presented for a beam and a shell. The beam is driven by a stationary load at a constant frequency. The shell is forced by a time-invariant load rotating around the shell at a frequency.
Producing VOT contrasts
Authors: Lofqvist Anders
Published: September 2013

The development of voice onset time (VOT) as an acoustic index for studying and classifying stop consonants also prompted a large number of studies examining laryngeal activity and interarticulator timing related to VOT. A collaboration between the Research Institute of Logopedics and Phoniatrics at the University of Tokyo and Haskins Laboratories resulted in a long line of studies using electromyographic and other techniques that provided much of the empirical foundations for what we know about laryngeal function in speech, in particular the production of voiced and voiceless consonants. This presentation will review the articulatory control of VOT differences. To make a consonant voiceless, a speaker uses a combination of glottal abduction and vocal fold tensing. The distinction between voiceless stops with long and short VOT is basically due to a difference in the timing between the glottal abduction gesture and the oral closing and opening gestures. Variations in the size of the glottal gesture also occur. More generally, variations in interarticulator timing between glottal and oral movements are used to produce the different stop categories that occur in the languages of the world. [Work supported by NIH.]
Physiological evidence for a temporal processing mechanism underlying voice-onset time (VOT) encoding
Authors: Steinschneider Mitchell , Fishman Yonatan I. , Volkov Igor O. , Howard Matthew A.
Published: September 2013

Despite decades of psychoacoustical research, the detailed neural mechanisms underlying VOT encoding remain obscure. Evidence collected from direct recordings in auditory cortex of human subjects undergoing surgical evaluation for medically intractable epilepsy, and from primary auditory cortex in monkeys, supports a temporal processing mechanism as a principal means by which VOT is encoded by the brain. This mechanism, as proposed by Pisoni [J. Acoust. Soc. Am. 77, 1352–1361 (1977)], argues that the perceptual discrimination of voiced from unvoiced stop consonants is based, in part, on whether consonant release and voicing onset are perceived as occurring simultaneously or sequentially. Neural activity in auditory cortex offers physiologically plausible parallels to this perceptual scheme that can help account for the distribution of typical VOT values used by the majority of the world’s languages, categorical perception of VOT, and perceptual boundary shifts that occur with changes in stop-consonant place of articulation and when nonspeech analogs of VOT are used. These responses in primary auditory cortex are poised to provide powerful inputs to later processing areas, where they can be integrated with other acoustical, visual, and language-related inputs known to modulate VOT perception. [Work supported by DC00657 and DC00120.]
Optimization of transmit/receive array processing for high rate acoustic communications
Authors: Stojanovic Milica
Published: September 2013

A broadband acoustic communication link between a user equipped with a single transmit/receive element and a station equipped with an array is considered. System optimization is conducted to obtain transmit/receive filtering techniques that provide best performance over a multipath channel under varying system constraints. Two classes of systems are considered: those that aim for complete intersymbol interference suppression and those that use equalization at the receiver side. Both systems are considered with or without the possibility to implement a perfect channel feedback. Transmit/receive filters are derived analytically, and performance of each scheme is assessed through its data detection SNR. Performance of various techniques is compared analytically, using an example of a shallow water channel, where transmission at high bit rate results in extensive delay spread.
Impact of thermocline and seabed variability on underwater acoustic communications
Authors: Siderius Martin , Porter Michael , Jensen Finn
Published: September 2013

Shallow water acoustic communications experiments were conducted near Kauai in July 2003 and near Capraia and Elba Islands in October 2003. All experiments took place in approximately 100-m water depth but the oceanography and seabed types differed significantly. The Kauai site had a reflective seabed that was combined with highly variable oceanographic conditions that led to performance closely tied to source/receiver geometry. The Capraia site also has a reflective seabed but the winter conditions produced a more mixed water column with a weaker and less variable thermocline than Kauai. The Elba site had nearly the same oceanographic conditions as Capraia but the seabed is a highly lossy. In each of these experiments, signals were transmitted over many hours from fixed and moving platforms and were received at multiple ranges and depths using vertical arrays and single hydrophones. Extensive environmental measurements were made simultaneous to the acoustic transmissions (e.g., measurements of the water column temperature structure and surface wave heights). In this paper, the correlation between environmental factors and communications performance will be presented along with the predictions from modeling. The performance of both multi-frequency shift keying (MFSK) and direct sequence spread spectrum (DSSS) signals will be discussed.
Comparison of two underwater acoustic communications techniques for multi-user access
Authors: Hursky Paul , Siderius T. Martin , Porter Michael B. ,   The KauaiEx Group
Published: September 2013

Frequency hopped frequency shift keying (FHFSK) and code division multiple access (CDMA) are two different modulation techniques for multiple users to communicate with a single receiver simultaneously. In July 2003, these two techniques were tested alongside each other in a shallow water coastal environment off the coast of Kauai. A variety of instruments were used to measure the prevailing oceanography, enabling detailed modeling of the channel. The channel was acoustically probed using LFM waveforms and m-sequences as well. We will present the results of demodulating the FHFSK and CDMA waveforms and discuss modeling the channel for the purpose of predicting multi-user communications performance. a)Michael B. Porter, Paul Hursky, Martin Siderius (SAIC), Mohsen Badiey (UD), Jerald Caruthers (USM), William S. Hodgkiss, Kaustubha Raghukumar (SIO), Dan Rouseff, Warren Fox (APL-UW), Christian de Moustier, Brian Calder, Barbara J. Kraft (UNH), Keyko McDonald (SPAWARSSC), Peter Stein, James K. Lewis, and Subramaniam Rajan (SSI).
Planarly layered diffraction tomography with accurate Green function
Authors: Lehman Sean K.
Published: September 2013

Diffraction tomography (DT) imaging techniques require knowledge of the background Green function. Due to its simplicity, it is standard practice to use a homogeneous medium Green function. We have developed a model of a planarly layered Green function that can be used in DT imaging of planarly layered media where the layer acoustical properties and dimensions are known. We present the theory and applications. [Work performed under the auspices of the U.S. Department of Energy by University of California, Lawrence Livermore National Laboratory under Contract W-7405-Eng-48.]
New methods in the analysis of resonances
Authors: Uberall H. , Werby M.
Published: September 2013

From water inclusions to layered elastic shells with included fluids, all may be analyzed by a common method. We demonstrate that the background method is always possible and is because solutions of linear nonhomogeneous, differential equations are composed of the supposition of the homogeneous solution plus a particular solution. Moreover, the partial wave solutions that arise in the usual developments have both inertial and damping components. We show that one may use these facts to determine both the resonance locations and the resonance widths and we present a context for which one may give meaning to observed resonance features.
Development of net cage acoustic alarm system
Authors: Hong Shih-Wei , Wei Ruey-Chang
Published: September 2013

In recent years, the fishery production has been drastically decreased in Taiwan, mainly due to overfishing and coast pollution; therefore, fishermen and corporations are encouraged by government to invest in ocean net cage aquaculture. However, the high-price fishes in the net cage are often coveted, so incidences of fish stealing and net cage breaking were found occasionally, which cause great economical loss. Security guards or a visual monitoring system has limited effect, especially in the night when these intrusions occur. This study is based on acoustic measure to build a net cage alarm system, which includes the sonobuoy and monitor station on land. The sonobuoy is a passive sonar that collects the sounds near the net cage and transmits the suspected signal to the monitor station. The signals are analyzed by the control program on the personal computer in the monitor station, and the alarms at different stages could be activated by the sound levels and durations of the analyzed data. To insure long hours of surveillance, a solar panel is applied to charge the battery, and a photodetector is used to activate the system.
The measurements technique of balance in opera houses: A study of the sources involved
Authors: Parati Linda , Pompoli Roberto , Prodi Nicola
Published: September 2013

The study of the acoustical balance between the singer and the orchestra by means of room acoustical measurements has shown that the directional characteristics of the source on the stage are important. This investigation compares the performance of two directional and one omnidirectional loudspeakers in emulating a soprano voice. Directivity measurements of a soprano singer were carried out in an anechoic chamber and used as a basis for comparison in room acoustic simulations of the Royal Theatre of Copenhagen, the Ankara Congress and Cultural Center, and the Alberta Jubilee Auditorium. In particular, the balance measurement was simulated and the performance of the different sources with respect to the soprano was assessed.
New Victory Theater
Authors: Scarbrough Paul , Nittoli Anthony
Published: September 2013

a)Paul Scarbrough was the principal-in-charge for Jaffe Holden Scarbrough Acoustics. Anthony Nittoli was senior project manager for Pro-Mix.
On my association with Bell Labs
Authors: Sondhi M. Mohan
Published: September 2013

I joined the Acoustics Research department at Bell Labs in 1962, just eight days before AT&T launched the first communications satellite, Telstar. During the 39 years between 1962 and my retirement in 2001, I worked on several problems related in one way or another to the processing of speech signals. Schroeder and Flanagan are presenting talks from a broad perspective in this session, so I will confine this talk to just my own contributions and collaborations for some of the topics on which I worked, e.g., echo cancellation, inverse problems in acoustics, speech analysis, synthesis, and recognition. I will tell you about one of these contributions that fortunately turned out to yield considerable profits to AT&T. To give you a flavor of the spirit of free inquiry at Bell Labs during that period, I will tell you about the contribution that I am most proud of (which was supported for several years even though it had no monetary value). And I will also mention the contribution that is most often cited of all my papers (which was in collaboration with two mathematicians, and had nothing at all to do with acoustics).
Sound detection and production in the American lobster, Homarus americanus: Sensitivity range and behavioral implications
Authors: Pye Heidi J. , Watson Winsor H.
Published: September 2013

Many crustaceans including spiny lobsters, some crabs, and a few shrimp are known to produce sounds for a variety of purposes. One brief report and several preliminary studies indicate that American lobsters also produce sounds, and may be capable of detecting acoustic signals. The focus of this study was to (1) quantify the frequency range over which lobsters are capable of detecting sounds and (2) characterize the sounds that lobsters produce. Twelve sexually immature and 11 mature lobsters were tested for their ability to detect frequencies in the range of 20–10000 Hz. Immature lobsters of both sexes detected sounds in the range of 20–1000 Hz (>50%), while sexually mature lobsters exhibited two distinct peaks in their acoustic sensitivity (20–300 Hz and 1000–5000 Hz). Lobsters of both sexes produced a buzzing vibration when grasped but larger lobsters (120–149 mm in carapace length) vibrated most consistently (>35% of surveyed lobsters). The greater tendency for sound production in large lobsters may indicate a role in mating behavior. Currently, we are characterizing the acoustical properties of produced sounds and investigating the possibility that the American lobster may produce sounds for more than one purpose. [Work supported by University of New Hampshire Center for Marine Biology.]
Soundscapes and their influence on inhabitants—New findings with the help of a grounded theory approach
Authors: Fiebig Andre , Schulte-Fortkamp Brigitte
Published: September 2013

Recent research work has shown the relevance of soundscapes with respect to community noise. A study was conducted aiming at clarifying and improving the comprehension between the acoustical stimulus and assessment, response, attitude, and perception of inhabitants in urban environments regarding their urban soundscapes. Narrative and issue-centered interviews were carried out to identify common perceptive patterns. Therefore subjects were required to articulate their opinions and sensations about their surroundings including environmental sound. At the same time acoustic measurements were performed. Therefore the study employs methodology of qualitative-interpretative research, since perception is constantly embedded in social contexts. By means of the ‘‘grounded theory’’ approach, a general methodology of qualitative social analysis, individual and interindividual determinants have been explored in the process of evaluating urban soundscapes based on a new integrative diagram. The new model will be presented.
Active field control for piano room
Authors: Ito Atsuko , Shimizu Yasushi
Published: September 2013

Active field control (AFC) is an innovative system that employs electroacoustic technologies enabling ‘‘natural changes’’ to major auditory impressions, such as reverberance, loudness, and spaciousness. This talk presents typical design concept of AFC application for a piano room with a low ceiling in architecture and with a miniconcert in program. The aim is to accommodate a condition appropriate for both a solo piano performance and a miniconcert, regardless of the low ceiling height and significant increase of absorption by the audience in a miniconcert. This can be realized by using an AFC system, which converts the room into different acoustical conditions as follows. One is that AFC alters acoustics of the designed space, and makes it sound as if it has a higher ceiling, which leads to a longer reverberation. The other is negative absorption to compensate added absorption with the audience for a miniconcert. In the presentation, these technologies will be presented, along with the acoustical data.
Virtual room modeling using hybrid digital waveguide mesh techniques
Authors: Beeson Mark J. , Murphy Damian T.
Published: September 2013

Digital waveguide mesh (WGM) models have been shown to be a viable method of obtaining accurate room impulse responses (RIRs) for a virtual space. However, the large memory and long processing requirements of these models have restricted their use for large rooms and for those with nontrivial geometric features. The development and inclusion of a KW-pipe interface allows the interconnection of finite difference and wave-based mesh implementations of a WGM model. The former is efficient for the main body of the mesh, with the latter, more processor intensive method allowing more accurate simulation at the boundaries of the modeled space. The resultant hybrid model removes some of the above computational constraints, allowing larger rooms and more complex geometries to be modeled. Model visualizations and RIR data are presented, demonstrating the correct operation of the KW-pipe interface. RIR data from two differing mesh topologies show that nontrivial geometries can be successfully modeled using this technique, with considerable computational savings on purely wave-based WGMs. Comparisons with RIRs obtained through more traditional ray-tracing and image-source techniques show favorable results and demonstrate the complex wave phenomena that are inherent in WGM models. [Work supported by EPSRC.]
On the simulation of seat-dip effect using geometrical acoustics software
Authors: Cirillo Ettore , Martellotta Francesco
Published: September 2013

A group of Italian churches was surveyed in order to measure the most important acoustic parameters according to ISO 3382 Standard. Computer models of the same churches were made using acoustic simulation software. Absorption coefficients found in the literature were used and later calibrated to match predicted and measured T30 values. The results of the simulations were compared with the observed values, showing some discrepancies at mid-low frequencies. This discrepancy appeared to be due to a lack of direct sound in the measured responses, particularly at the 250-Hz and 500-Hz octave bands, indicating the probable presence of a seat-dip effect caused by the wooden pews. Since the acoustic simulation software provided the possibility to use acoustically semitransparent planes, this feature was used to simulate the effect of selective absorption of the direct sound due to the seat-dip effect. The comparison between measured acoustic parameters and those predicted including the simulation of the seat-dip effect showed that an improvement in the prediction accuracy can be achieved. Different configurations were tested in order to define the optimal placing of the semitransparent plane, and a criterion to choose the transparency coefficients is finally proposed.