bluuebunny/crossref_metadata_2025 huggingface dataset:
Socioeconomic status and the experience of noise
Authors: Fyhri Aslak
Published: October 2013

In this study how road traffic noise is experienced in an affluent (western) and a more deprived (eastern) area of Oslo is compared. The results are based on interviews with 1400 people in Oslo, together with calculations of 24 h equivalent noise levels at each individual apartment’s most exposed side (the Nordic calculation method). People in the western part of town report far more positive qualities in their neighborhood than those in the east. They are more satisfied with the visual aesthetics of the neighborhood, the quality of outdoor areas, the level of air pollution, and the central location of the city area. The only exception to this somewhat rosy picture is the exposure to road traffic noise. There are more people (31% of the respondents) exposed to noise levels above 65 dBA in the western area, than in the eastern area (11%). The respondents in the west are also more annoyed by road traffic noise, compared with those in the east. When controlling for individual noise levels, the results do not support the hypothesis.
The sagrada familia: A daily whisper of the spirit
Authors: Campos Arturo
Published: October 2013

Sounds from the top of the Temple; songs of loyals going beyond the city, sounds of the rustic forms of the spaces for the soul; reality and miracle in just one voice, voice of religion for participation; mystery, mysticism, meditation, happiness, music and songs, bells and church towers, choirs and pulpits, religion and city. The religious architecture of Gaudi is involved by mystic sounds, real or imaginary sounds, whispers almost imperceptibles and sonorous surprises in the journeys destined to peace and spiritual calm. The Sagrada Familia in Barcelona is a Temple where the sonorous itineraries will exist and where the acoustic design of choirs, bells and bell towers was an essential idea of Antoni Gaudi. A living building with its voice singing with the people a song which will take in the whole city; ringing bells and bell towers crossing the sky and sending music, view and hearing of all the people to the new cathedral, a symbol to guide pilgrimages, ceremonies, songs and festivals. The Sagrada Familia and Barcelona, a union that Gaudi wanted to turn in total and where the acoustic design will be transformed in a daily murmur, highly spiritual. (To be presented in Spanish.)
A comparison of radiosity with current methods of sound level prediction in commercial spaces
Authors: Beamer C. Walter , Muehleisen Ralph T.
Published: October 2013

The ray tracing and image methods (and variations thereof) are widely used for the computation of sound fields in architectural spaces. The ray tracing and image methods are best suited for spaces with mostly specular reflecting surfaces. The radiosity method, a method based on solving a system of energy balance equations, is best applied to spaces with mainly diffusely reflective surfaces. Because very few spaces are either purely specular or purely diffuse, all methods must deal with both types of reflecting surfaces. A comparison of the radiosity method to other methods for the prediction of sound levels in commercial environments is presented. [Work supported by NSF.]
Characterization of the occupational noise environment of the Portuguese textile sector
Authors: Arezes Pedro M. , Miguel A. Sergio
Published: October 2013

In this study we aim to characterize the occupational noise environment of five large industrial companies of the textile and apparel sector, as well as the audiometric profile of the exposed workers. All individual exposures were classified into three categories: namely (1) acceptable risk: personal noise exposure level below 85 dB(A); (2) moderate risk: personal noise exposure level between 85 and 90 dB(A); and (3) high risk: personal noise exposure level greater than 90 dB(A). It was observed that the majority of the workplaces presented personal exposure levels greater than 90 dB(A), thus involving a high risk of bilateral hypoacusia. In some areas, such as weaving, that percentage exceeded 90%. Workers’ audiometric profiles were analyzed according to the professional disease criteria presented by the Portuguese legislation. An effort should be made for developing Hearing Conservation Programs leading to the implementation of collective and personal protective measures. [Work supported by the Portuguese Institute for Development and Inspection of Working Conditions (IDICT).] (To be presented in Portuguese.)
Application of acoustic spectroscopy to rocks
Authors: Zadler Brian J. , Scales John A.
Published: October 2013

Resonant ultrasound spectroscopy techniques were used on dried Elberton granite to infer elastic moduli and obtain experimental uncertainties for the Q values of the eigenmodes. A suite of independent measurements was performed on a 2.26-cm-diameter, 7.15-cm-long cylinder mounted between piezoelectric acoustic transducers. An orthorhombic model was fit resulting in an inferred 10% compressional wave anisotropy perpendicular to the symmetry axis. This is consistent with ultrasonic noncontacting tomography measurements made by Malcolm [A. Malcolm and J. A. Scales, preprint, 2001]. Observed Q values ranged from 80 to 206 pm41 over the range 20 to 90 kHz, showing a significant variation due mostly to mounting. Theory is being developed for simple isotropic pseudo-rocks to link dry moduli Mdry and single monolayer moduli Mmono to pore properties to better understand measured Q. It was observed by Tittman [B. R. Tittman, V. A. Clark, and J. M. Richardson, J. Geophys. Res. 85, 5199–5208 (1980)] that the effects of a single monolayer of water coating the pore space can significantly impact measured Q. [Work supported by Center for Wave Phenomena and Center for Rock Abuse, Colorado School of Mines.]
Mapping out fiber directions in composite laminates using ultrasound
Authors: Hsu David K.
Published: October 2013

A method for ultrasonically mapping out the fiber orientation of the plies in a composite laminate is presented. The method employs normal-incidence longitudinal ultrasound but exploits the presence of small structural imperfections that are always present at the interfaces between plies. C-scan images of ply interfaces contain streaking features that contain fiber orientation information; however, such images can often be quite noisy and the fiber orientations were difficult to discern visually. To overcome such difficulties, 2-D FFT was applied to the C-scan image of an interface, and the resultant amplitude-versus-angle plot was used to determine the fiber orientation. Since the ply thickness was an unknown and the interface echoes were usually not distinct, the placement of time windows was impractical. Therefore, the entirety of full-waveform B-scan data were used. The 2-D FFT was performed on C-scan slices at small time (depth) increments regardless of the actual location of the ply interfaces. This method was more robust and worked successfully on a large variety of composite laminates. [Work supported by NSF IUCRC.]
Simulations of elastic wave propagation through Voronoi polycrystals
Authors: Turner Joseph A. , Ghoshal Goutam
Published: October 2013

The scattering of elastic waves in polycrystalline media is relevant for ultrasonic materials characterization and nondestructive evaluation. Ultrasonic attenuation and backscatter are routinely used for extracting microstructural parameters such as grain size and grain texture. The inversion of experimental data requires robust ultrasonic scattering models. Such models are often idealizations of real media through assumptions such as constant density, single grain size, and randomness hypotheses. The accuracy and limits of applicability of these models cannot be fully tested due to practical limits of real materials processing. Here, this problem is examined in terms of numerical simulations of elastic waves through two-dimensional polycrystals. The numerical models are based on the Voronoi polycrystal. Voronoi tessellations have been shown to model accurately the microstructure of polycrystalline metals and ceramics. The Voronoi cells are discretized using finite elements and integrated directly in time. The material properties of the individual Voronoi cells are chosen according to appropriate distributions here, cubic crystals that are statistically isotropic. Results are presented and compared with scattering theories. Issues relevant to spatial/ensemble averaging will also be discussed. These simulations will provide insight into the attenuation models relevant for polycrystalline materials. [Work supported by DOE.]
Acoustical properties of finite sonic crystals slabs
Authors: Håkansson Andreas , Sánchez-Dehesa José , Sanchis Lorenzo , Cervera Francisco
Published: October 2013

This work shows that a slab consisting of a periodic distribution of rigid cylinders in air constitutes a sort of acoustic interferometer with properties similar to its lightwave counterpart. The performance of this finite sonic crystal has been analyzed experimentally as well as theoretically as a function of its thickness and the symmetry configuration of the cylinders. Thus, reflectance spectra have been obtained by using the standing wave ratio technique. Experimental observations are well reproduced by a self-consistent wave theory that incorporates all orders of multiple scattering. In particular, this theory allows obtaining the complex frequencies of internal modes responsible for zero reflectance features observed in the spectra. [Work supported by CEAL-BSCH and CICyT of Spain.]
Evaluation of periodgrams as a tool to study spectral densities of heterodyne signals
Authors: Alvarado Jose Manuel , Stern Catalina
Published: October 2013

The use of periodgrams as a tool to study heterodyne signals is evaluated. The heterodyne signal carries information about density fluctuations from light scattered by a turbulent jet. The goal of the analysis is to be able to separate the information about density fluctuations of acoustics origin (peaked at about 2 MHz) from fluctuations in the density due to entropy irregularities (wide peak centered at the origin). There are frequency regions where both overlap. Various methods are compared: Bartlett, Welch, Yule–Walker, Burg and others. (To be presented in Spanish.)
Rayleigh scattering to study acoustic waves in a turbulent jet flow
Authors: Azpeitia Carlos , Aguilar Cesar
Published: October 2013

Rayleigh scattering is used as a visualization technique to study density fluctuations due to acoustical waves produced at the exit of a turbulent air jet flow. Scattering is produced by sending a 532-nm laser beam through the flow. The scattered light is collected by a lens and projected to a screen to achieve an image. Pictures showing the crossover between expansion and compression waves in the jet have been obtained. The technique allows the mapping of the pattern of shock waves along the jet. These pictures can provide information of the exit velocity by analyzing the angle formed by the waves closest to the nozzle. Rayleigh scattering can also be used in an alternative technique that detects the scattered light by heterodyning. The current that comes out of the photodetector is proportional to the spatial Fourier transform (for a particular wave vector) of the density fluctuations as a function of time. [Work supported by UNAM through the DGAPA Project No. IN107599.]
Photoacoustic study of gaseous carbon disulfide with a pulsed nitrogen laser
Authors: Cheyne Stanley A. , McDermott Walter C.
Published: October 2013

The photoacoustic effect has been used to study gaseous Carbon Disulfide. A 1.25-MW nitrogen laser having a wavelength of 337 nm and pulse duration of 800 ps was used as the photoacoustic source when typically, continuous-wave lasers modulated at the resonant frequency of the photoacoustic test cell are used to detect rarified gases. For this work, several photoacoustic test cells, designed and constructed to optimize the acoustic signal, were used in order to detect the presence of a gas at low concentration. A variety of detectors were used including a condenser microphone, PVDF tranducer, optical probe beam deflection, and a fiber optic sensor. Results will also be presented showing the relationship between gas concentration and pressure.
Ultrasonic investigations of water mixtures with polyethylene glycol 1000
Authors: Linde Bogumil B. J. , Schmelzer Christian , Rosenfeld Eike
Published: October 2013

The velocity of ultrasound and density were measured in the mixture of polyethylene glycol 1000 and water in the temperature ranges 283–308 K. These results allowed us to calculate the adiabatic compressibilities from the Laplace equation. The compressibility dependencies on the temperature and concentration are presented as group of isotherms with one common point of intersection. Such a relation between adiabatic compressibility and concentration and temperature indicates the formation of a liquid pseudostable structure. It was compared with the solid clathrate. This structure were suggested by Baumgarten & Atkinson as well as by Endo, although the interpretation was different. The first authors relate the formation of clathrate structure to the minima of the compressibility isotherms but according to Endo the intersection of the compressibility isotherms are related to such a structure. None of these were applicable to the results.
Comparative study of acetate, chloride and nitrate ions in aqueous and methanol media
Authors: Ghandhimathi Rajarathinam
Published: October 2013

A good deal of work has been carried out in aqueous and methanol solutions of various electrolytes at various concentrations and different temperatures ranging from 15°C to 55°C through ultrasonic measurements which provide qualitative information regarding the elastic forces between molecules on the basis of internal pressure and free volume. The variation of internal pressure and free volume of nitrate, chloride, and acetate ions in aqueous and methanol solutions is compared. It is found that the internal pressure increases rapidly with concentration in chloride systems and decreases with concentration in solutions of nitrates. It increases very slightly with concentration in the case of acetates. The difference in internal pressure predicts the nature of solute. If the difference in internal pressure is positive, the solute has a tendency to enhance the internal pressure of the solvent when added to it. Hence, there is an increase in internal pressure in the case of chloride ions. If the difference in internal pressure is negative, the internal pressure will decrease, which is observed in the case of nitrate ions.
An acoustic model of normal speech prosody
Authors: Casper Maureen A. , Raphael Lawrence J. , Harris Katherine S.
Published: October 2013

Investigations of the mechanisms underlying durational effects have shown that the displacements and velocities of articulator movement for the same acoustic-phonetic segments are variable. Kinematic measures reveal more extreme displacements and increased velocity in stressed syllables as compared to weakly stressed syllables [Cohen et al., J. Acoust. Soc. Am. 98, 2894(A) (1995)], except for those in phrase-final position. To further our understanding of the acoustic consequences of prosodic variations, six normal speakers read sentences containing the syllable [pap] in response to a series of questions. Pairwise comparisons of the prosodic conditions showed statistically significant differences for four prosodic contrasts. For three of the four contrast, the speakers showed longer syllable durations and higher formant and f0 frequency values for stressed syllables. In the phrase-final accented versus non-phrase-final accented contrast, however, the phrase-final accented syllables, although showing longer syllable duration, displayed lower frequency values for F1, F2, and f0. These data suggest a model in which time emerges as a function of articulatory events rather than a determiner of those events.
Continuous temporal alignment of an F0 peak produces categorical behavior
Authors: Redi Laura C.
Published: October 2013

Assessing which aspects of fundamental frequency (F0) contours speakers are capable of reliably reproducing provides insight into how F0 patterns should be modeled for synthesis purposes, as well as how speakers represent such patterns. This experiment investigated the reproducibility of the temporal alignment of an F0 peak with respect to a stressed syllable. Subjects were required to imitate a series of synthetic stimuli in which an F0 peak was shifted through the stressed and following weak syllable of the word minglingly. Preliminary results showed that F0 peaks in the subjects’ reproductions of the stimuli clustered about the midpoint of the stressed or following weak syllable when the corresponding stimulus had a peak in the stressed or following weak syllable, respectively. Moreover, relatively large variation within a syllable in stimulus peak timing resulted in little variation in peak timing in subjects’ corresponding reproductions, while stimuli with peaks near the boundary between the stressed and weak syllables induced a large degree of variation in peak timing in the subjects’ reproductions. This suggests that listeners may be making categorical distinctions between some intonation patterns based on the temporal location of an F0 peak with respect to a stressed syllable. [Work supported by NSF.]
Strategies for the timing of the fundamental frequency contour
Authors: Lyberg Bertil
Published: October 2013

The acoustic manifestation of the prosodic features are heavily influenced by the segmental composition of the utterances. In investigations about the fundamental frequency contour utterances built of only sonorants are often used and thereby the influence of constrictions of the vocal tract is avoided or at least diminished. In order to arrive at a detailed model of the fundamental frequency it is necessary to exactly know what is happening in different segmental environments. In the present study we are examining the effects which voiceless consonants have upon the fundamental frequency contour. Three different hypotheses are considered: the truncation, the timing adjustment and the rate adjustment hypothesis. The results show that the truncation hypothesis seems to be of limited validity at least from a detailed description of the fundamental frequency contour.
Modeling prosody: Different approaches
Authors: Carmichael Lesley M.
Published: October 2013

Prosody pervades all aspects of a speech signal, both in terms of raw acoustic outcomes and linguistically meaningful units, from the phoneme to the discourse unit. It is carried in the suprasegmental features of fundamental frequency, loudness, and duration. Several models have been developed to account for the way prosody organizes speech, and they vary widely in terms of their theoretical assumptions, organizational primitives, actual procedures of application to speech, and intended use (e.g., to generate speech from text vs. to model the prosodic phonology of a language). In many cases, these models overtly contradict one another with regard to their fundamental premises or their identification of the perceptible objects of linguistic prosody. These competing models are directly compared. Each model is applied to the same speech samples. This parallel analysis allows for a critical inspection of each model and its efficacy in assessing the suprasegmental behavior of the speech. The analyses illustrate how different approaches are better equipped to account for different aspects of prosody. Viewing the models and their successes from an objective perspective allows for creative possibilities in terms of combining strengths from models which might otherwise be considered fundamentally incompatible.
Rhythmic organization of read word lists
Authors: Cummins Fred
Published: October 2013

Rhythmic constraints have been notoriously hard to identify in speech timing. Appropriate experimental tasks may help in identifying grouping principles and timing constraints. In a baseline experiment, subjects read wordlists which contained eight trochees. They were instructed to read the words with regular timing. The inter–onset intervals obtained show evidence of a binary grouping into ‘‘feet’’ containing two words each, and of two-word feet grouping into 4-word super-feet. Results were consistent with a hierarchical rhythm grouping of units into pairs, with the second element of each such group exhibiting some degree of deceleration or final lengthening. In a second condition, each word list contained 7 trochees and one (list medial) iamb. Inter–onset intervals suggest that a similar grouping takes place, with the stressed syllable of the iamb, rather than the first syllable, marking the onset of a unit. In a third condition, the iamb was preceded by a dactyl, giving a 4-syllable foot. Again, results suggest that the stressed syllables, rather than word onsets, delimit production units. Together the results suggest that the stress foot is a unit which serves to structure speech in time.
The influence of onset-density in speech production
Authors: Vitevitch Michael
Published: October 2013

Numerous studies have suggested that the initial phoneme (or syllable onset) plays an important role in speech perception and production. Recent findings have also demonstrated the importance that the number of similar sounding words plays in lexical retrieval during speech perception and production. The results from a picture-naming task demonstrate that the number of words that share the onset of the target word (onset-density) also influences speech production as well as speech perception. Specifically, pictures of words with sparse onsets were named more quickly than pictures of words with dense onsets. These results suggest that lexical and sublexical information interact during lexical retrieval in speech production. The implications for feedforward and feedback models of speech production will be discussed.
Effects of prosodic position and phonetic context on Spanish coda stops
Authors: del-Teso-Craviotto Marisol
Published: October 2013

The paper reports on a study of Peninsular Spanish stops in coda position. The voicing and duration of the stops [b p d t g k] was measured in initial (V.CV) and syllable final (VC.C) contexts to study the possible effects of prosodic position and segmental phonetic context on the realization of the stops under study. Results show that in initial position, stops overwhelmingly surface with their underlying voicing, whereas in coda position there is evidence of weakening processes. Thus voiceless stops have voiced outcomes in 56.4% of the cases. However, weakening cannot account for the high percentage of voiceless outcomes for both underlying voiceless and voiced stops in coda position (43.6% and 31.7%, respectively.) The majority of these voiceless outcomes can be accounted for by regressive assimilation. The results of the study also show voicing differences between stops followed by obstruents, which surface as voiced in 52.1% of the cases, and the stops followed by sonorants, which surface as voiced 80.6% of the time. This difference provides limited support for Steriades [manuscript (1999)] proposal that voicing is licensed by particular phonetic cues and not by prosodic position [L. Lombardi, Natl. Lang. Ling. Theory 13, 39–74 (1995)].
Acoustic profiles of negative emotion
Authors: Pell Marc D.
Published: October 2013

A study was initiated to acoustically characterize and differentiate discrete categories of negatively valenced emotions conveyed through speech prosody. Utterances elicited from eight encoders (actors) in different emotional tones were perceptually rated by a group of decoders to gauge how strongly each token was associated with the basic emotions of ‘‘anger,’’ ‘‘disgust,’’ and ‘‘sadness’’ using a seven-choice response paradigm. Tokens rated as highly representative of each target emotion by greater than 80% of decoders were examined acoustically. Measures of fundamental frequency (mean, range, sd), amplitude (mean, range, sd), and duration (speech rate, %voiced) were obtained from each token and for utterances spoken in a ‘‘neutral’’ tone by the same encoders. Normalized measures were compared among emotional categories to uncover reliable acoustic dimensions that may have contributed to perceptually distinct vocal symbols of negative emotion states. Results pointed to important differences in duration, amplitude, and especially fundamental frequency in discriminating among prosodic signals representing distinct negative emotions. These findings extend work on the acoustic underpinnings of positive and negative vocalizations in speech [M. D. Pell, J. Acoust. Soc. Am. 109, 1668–1680 (2001)], providing finer specification of these parameters within the family of ‘‘negative’’ emotions. [Work supported by NSERC.]
The link between prosody and meaning in the production of emotional homophones
Authors: Nygaard Lynne C. , Patel Neelam , Queen Jennifer S.
Published: October 2013

Recent research has shown that characteristics of a talker’s voice are preserved in memory representations of spoken words. These findings suggest that aspects of surface form that co-occur frequently with a word’s phonological form and meaning may influence lexical processing. To determine if surface form is linked to word meaning, this study examined the production of emotional homophones including one emotional (happy or sad) and one neutral meaning, each with distinct spellings (e.g., bridal/bridle). It was hypothesized that each meaning of these homophones would be linked to different characteristic surface forms, with emotional prosody linked to the emotional meaning and no systematic prosody linked to the neutral meaning. Participants read aloud either the emotional or the neutral spelling of each homophone and their utterances were recorded and acoustically analyzed. For happy homophones, average fundamental frequency and rms amplitude were higher when participants read aloud the happy spelling than when they read the neutral spelling of the same homophone. For sad homophones, shimmer and jitter measures were greater when reading the sad then the neutral spelling. These results suggest that emotional prosody is linked to emotional meaning in spoken words and this link appears to guide speech production.
The effects of talker characterisics on implicit memory for spoken sentences
Authors: Queen Jennifer , Nygaard Lynne , Barsalou Lawrence
Published: October 2013

Recent research has shown that surface characteristics of speech such as talker identity are retained in long-term memory for individual spoken words, but little research has examined retention of surface form in the processing of larger linguistic units. The present experiment investigated the effects of talker identity and talker-relevant background information on implicit memory for spoken sentences. Listeners heard a conversation between two speakers. The conversation focused on 2 topic areas, football at Emory and lunching at the dining hall. At test, listeners were presented with sentences in noise that were either previously heard in the conversation or new sentences on the same topics. Half of the old test items were spoken by the speaker who said them during the conversation and half were spoken by the other speaker. Results showed that listeners correctly identified more sentences at test when they were repeated by the same speaker than by the other speaker. The results suggest that talker characteristics are retained and used in sentence as well as spoken word recognition.
Difference limen for aspiration noise in perception of breathy voice quality
Authors: Shrivastav Rahul , Sapienza Christine
Published: October 2013

Despite much research, the relationship between the vocal acoustic signal and the perception of breathy voice quality is debated. Shrivastav (2001) used an auditory model to study the perception of breathy voice quality and found that listeners’ perception of breathiness was related to the partial loudness of the periodic energy obtained with the aspiration noise acting as a masker. This measure was found to be a better predictor of perceptual judgments than conventionally used acoustic measures of breathiness. The aim of the present experiment was to determine the minimal change in aspiration noise that led to a change in the perception of breathiness. A continuum of voices, identical in all aspects except aspiration noise, was synthesized using a Klatt synthesizer. These stimuli were presented in pairs and listeners identified each pair as being the same or different in terms of their breathiness. Percent-correct scores for each stimulus pair were calculated and compared with differences in the acoustic and auditory spectral measures. Findings of this experiment may be useful in the development of objective tools for the quantification of breathy voice quality.
EM sensor measurement of glottal structure versus time
Authors: Holzricher John F. , Ng Lawrence C. , Burke Gerald J. , Kobler James B. , Rosowski John J.
Published: October 2013

EM wave sensors are being used to measure human vocal tract movements during voiced speech. However, when used in the glottal region there remains uncertainty regarding the contributions to the sensor signal from the vocal fold opening and closing versus those from pressure induced trachea–wall movements. Several signal source hypotheses were tested on a subject who had undergone tracheostomy 4 years ago as a consequence of laryngeal paresis. Measurements of vocal fold and tracheal wall motions were made using an EM sensor, a laser-Doppler velocimeter, and an electroglottograph. Simultaneous acoustic data came from a subglottal pressure sensor and a microphone at the lips. Extensive 3-D numerical simulations of EM wave propagation into the neck were performed in order to estimate the amplitude and phase of the reflected EM waves from the 2 different sources. The simulations and experiments show that these sensors measure, depending upon location, both the opening and closing of the vocal folds and the movement of the tracheal walls. When placed over the larynx, the vocal folds are the dominant source. The understanding of the signal sources is important for many potential applications under consideration.
On the acoustic effects of piriform recesses in speech production
Authors: Cha Jul Setsu , Alwan Abeer
Published: October 2013

The 3-D vocal tract (VT) geometries for several talkers were reconstructed from consecutive 2-D MR images. Cross-sectional areas were then estimated and the corresponding VT transfer functions were synthesized using an articulatory speech synthesizer. Geometries for eleven English vowels spoken by two males, and seven vowels by one female were obtained. The acoustic effects of the piriform recesses, which extend interiorly on either side of the larynx, were studied by modeling the recesses as side branches. For many vowels, the inclusion of the piriform recesses, which results in lowering the formant frequencies, yields better estimates of the natural formants. The largest effect is noticed on F1 where the value of the formant is inversely related to the recesses’ lengths. In addition, zeros in the VT transfer function are created and estimated well when the length of the recess is large. The length of a piriform recess seems to have a larger effect than the volume on the location of the zero frequencies in the modeled VT frequency response. Detailed results are presented and compared to other studies that examined the acoustic effects of these recesses [Dang and Honda, J. Acoust. Soc. Am. 101, 456–465 (1997); Story et al., ibid. 104, 471–487 (1998)].
Histological investigation of the supra-glottal structures in humans for understanding abnormal phonation
Authors: Kimura Miwako , Sakakibara Ken-Ichi , Imagawa Hiroshi , Chan Roger , Niimi Seijii , Tayama Niro
Published: October 2013

Phonation is the vocal fold vibration on normal voice. But sometimes we can observe the other phonation styles like as the pressed voice or some throat singings like as ‘‘kargyraa’’ or ‘‘drone’’ in Khoomei in Mongolian music. Also, clinically, we know that some patients who have the wide glottal slit in phonation because of the recurrence nerve palsy or after partial laryngectomy, could make the ‘‘supra-glottal phonation.’’ The ‘‘supra-glottal phonation’’ would be made from the vibration of ‘‘supra-glottal structures’’ such as the false vocal folds, the arytenoids and the epiglottis, etc. Endoscopic examination suggests the existence of some contractile functions in supra-glottal space. However, these phonation systems have not been clear to explain their neuromuscular mechanism in histology. This study aimed to find the basis for making the supra-glottal phonation from the points of view of the histological structures. We tried to investigate if there were any muscles that could contract the supra-glottal structures. The samples are the excised larynx of human beings. They were fixed by formalin after excision. We observed their macroscopic anatomy, and also with the microscopic observation their histological preparations after the process of the embedding in paraffin, slicing for the preparation and HE (hematoxylin-eosin) staining.
Real time inverse filter focusing by iterative time reversal
Authors: Montaldo Gabriel , Tanter Mickael , Fink Mathias
Published: October 2013

In order to achieve an optimal focusing through heterogeneous media, we need to build an inverse filter of the propagation operator. Time-reversal achieves such an inverse filter in nondissipative media. However, as soon as losses appear in the medium, time-reversal is no more equivalent to an inverse filter. Consequently, it does no more produce the optimal focusing and beam degradations may appear. In such cases, previous works have shown that the optimal focusing can be recovered by using a spatiotemporal inverse filter technique. This process requires the presence of a set of receivers inside the medium but allows us to reach the optimal focusing even in extreme situations such as ultrasonic focusing through a human skull. To date, it remained time consuming and implied fastidious numerical calculations. We propose here a new way to process this inverse filtering in real time and without any calculation. The new process is based on iterative time-reversal processing. Contrary to the classical inversion, this iteration does not require any computation as it achieves the inverse filter experimentally using waves propagation instead of computational power. The feasibility of this iterative technique is theoretically and experimentally demonstrated for ultrasound applications and its potential for telecommunications is discussed.
Broadband-DORT applied to bistatic active sonar
Authors: Fromm David M. , Gaumond Charles F.
Published: October 2013

The decomposition of the time reversal operator (DORT) is a single frequency method of spatially isolating scatterers with a multiple-source/multiple-receiver system [C. Prada, S. Manneville, D. Spoliansky, and M. Fink, J. Acoust. Soc. Am. 99, 2067–2076 (1996)]. This technique has 8 been extended into a coherent, broadband method. Broadband DORT has also been shown to isolate resolvable scatterers at various depths and ranges in a bistatic, active sonar in shallow water. Several limitations of the method are demonstrated through the use of numerical simulations and backpropagations. One limitation is the resolvability of a system in shallow water. The dependence of resolution on environmental parameters, e.g., signal-to-noise ratio, water depth, bottom parameters and sound speed profile—and system parameters—e.g., frequency content and source/receiver configuration—is shown by forming images of a single scatterer, two scatterers and many scatterers. The limits of continuity over frequency of the broadband singular vectors and values caused by frequency fading are also shown through data visualization techniques. [Work supported by ONR.]
Algorithms and architectures for highly efficient digital beamforming of acoustic arrays
Authors: Woodsum Harvey , Hogan William , Gaidos John
Published: October 2013

The creation of broad bandwidth, directional transmit beams with an (N×M element) acoustic transmitting array normally requires generation NM time delayed versions of the signal to be transmitted, with precise control required for each signal channel. Similarly, for generation of a directional receive beam, NM time delays are needed to be applied to the receive channels, which are then weighted and summed to create the beam output time series. Recently, an architecture has been developed which allows efficient beamforming with a much smaller number of delayed channels, this being on the order of the square root of the number of elements, for planar geometries, and on the order of the cube root of the total number of elements for volumetric arrays, thus achieving an enormous savings in beamforming complexity. With this approach, an offline genetic algorithm is utilized to select time delays and a one to many mapping function, to allow minimization of the number of delays to be applied, according to a fitness criterion which optimizes the process toward the ideal case. An actual hardware implementation in which this algorithm and architecture has been successfully utilized is described.
Improving noise source location using the unwrapped phase method
Authors: Wang Yongxin , Darvennes Corinne
Published: October 2013

Time Delay of Arrival (TDOA) is the key to using a microphone array for sound source location. The Unwrapped Phase (UP) Method has been used to estimate the TDOA, which is proportional to the slope of the phase of the cross-power spectrum plotted versus frequency. However, reflecting surfaces cause ‘‘jumps’’ in the phase plot. A Zero-Magnitude of Transfer Function (ZMTF) criterion is proposed to automatically pick up the ‘‘jumps’’ to better estimate the TDOA. To verify this, tests were performed in three rooms with different acoustical properties. The sound source consisted of a speaker broadcasting a computer-generated broadband random signal. ZMTF works well in an ordinary room with small reverberation and yields accurate TDOA results. An average error of 0.2% is obtained. In a medium-sized live room, ZMTF identifies ‘‘jumps,’’ and an average error of 1.6% is obtained. In a large reverberation room, however, ZMTF only marginally improved the UP method. The norm of residues and Delay Error were found helpful to evaluate the best results.
Nonlinear internal wave energy dissipation and evolution on the South China Sea Slope
Authors: Orr Marshall H. , Mignerey Peter C.
Published: October 2013

Nonlinear internal waves have been observed propagating up the slope of the South China Sea during the recent AsiaEX experiment. Energy dissipation rates have been extracted. The location of the initiation of the depression to elevation conversion has been identified. Scaling parameters have been extracted and used to initialize a two-layer evolution models simulation. The calculations are compared to the in situ observations. [Work supported by the ONR Ocean Acoustic Program and ONRs NRL base funding.]
Acoustic beam broadening by solitary bores during ASIAEx 2001 (South China Sea)
Authors: Wolf Stephen N. , Pasewark Bruce H. , Orr Marshall H. , Lynch James F. , Chiu Ching-Sang
Published: October 2013

Previous theoretical and modeling studies have predicted that acoustic interaction with anisotropic internal wave fields will introduce mode-order-dependent horizontal refraction, thereby limiting the resolution of horizontal receiving arrays. An experiment to observe this phenomenon was performed on the continental shelf southwest of Taiwan. A nonlinear, bottom-laid horizontal array received signals over an 18-day period from two sound sources (300 and 500 Hz) located 18 km to the northeast. Water depth along the propagation path was in the range 110–180 m. The prevailing downward-refracting sound speed profile was modulated by internal waves. At semidiurnal intervals strong internal bores originating in the Luzon Strait entered the propagation path at the source position, introducing strongly anisotropic sound speed perturbations. The wavecrests of the internal bores’ surface expression were oriented at typical angles 20–30 deg with respect to the acoustic propagation path. Aperture-limited signal beam widths (FWHM), nominally 1.5 deg, were broadened while the semidiurnal bores were in the acoustic propagation path. Details of the acoustic and oceanographic measurements and model calculations of beam broadening by the sound speed perturbations will be presented. [Work supported by ONR.]
Acoustic signal spatial and temporal correlation variability in the ASIAEx 2001 South China Sea experiment
Authors: Pasewark Bruce H. , Wolf Stephen N. , Orr Marshall H. , Lynch James F.
Published: October 2013

Broadband acoustic signal intensity fluctuations, temporal correlations, and horizontal spatial correlations have been extracted from a horizontal array data set. The relationship between the acoustic signal variability and the fluid processes that perturb the sound-speed field will be discussed. The 2.048-s linear frequency-modulated signals were received on a 450-m horizontal array. The signals were centered at 300 and 500 Hz and had respective bandwidths of 60 and 90 Hz. The signal intensity was found to fluctuate by 10 to 20 dB as a function of time and space. Horizontal correlation length varied over time from 5 to 100 acoustic wavelengths and the signal correlation time ranged from 1 to 50 min. The data were acquired in May 2001 during the Asian Seas International Acoustics Experiment (AsiaEx). The 18-km acoustic propagation path lay along a 125-m isobath at the South China Sea shelf break. The experiment site was oceanographically dynamic, with energetic internal gravity wave fields and currents that strongly impacted the acoustic propagation. [Work supported by ONR.]
Three-dimensional acoustic effects in the ASIAEX SCS experiment
Authors: Chen Chi-Fang , Hsieh Li-Wen , Oba Roger , Finette Steven
Published: October 2013

A three-dimensional ocean environment is generated using measured ocean data from the ASIAEX South China Sea experiment. The experiment site is characterized as an active internal tide/solibore propagation region along the Northwestern shelf break of the South China Sea. The three-dimensional acoustic effects are studied using a wide-angle version of the parabolic equation code for3d. Mode coupling matrices and horizontal refractions are shown to demonstrate the 3-D effects. Variations in topography of the shelf break and in the water column due to the internal solibore propagation cause significant mode coupling and 3-D effects in the acoustic field. [Work supported by National Science Council of Republic of China for first and second authors. Work supported by ONR for the third and fourth authors.]
Observations and modeling of acoustic intensity fluctuations seen during the 1996 summer New England shelfbreak PRIMER experiment
Authors: Fredricks A. , Colosi J. , Lynch J. , Gawarkiewicz G. , Duda T. , Chiu C.-S. , Abbott P.
Published: October 2013

In this paper we discuss the intensity fluctuation characteristics of 400-Hz acoustic transmissions made in the Mid-Atlantic Bight during the summer of 1996. The transmissions traversed variable topography, the dynamic shelfbreak front, and strong nonlinear internal waves, all of which affected the acoustic propagation. In studying the intensity fluctuations, we look both at data from the PRIMER vertical line array receiver and at output from a broadband parabolic equation model intended to simulate the experimental conditions with high fidelity. The statistics of the fluctuations, the physical causes of the fluctuations, and the correlation with the oceanographic forcing in different frequency bands (subtidal, tidal, and high frequency) all are examined. [Work supported by ONR.]
Tutorial on Industrial Noise Control
Authors: Gerges Samir N. Y. , Tinianov Brandon
Published: October 2013

This tutorial is intended to provide a practical overview of applied acoustics and industrial noise control, including the fundamentals of applied acoustics, industrial noise control and case histories. The following topics will be covered: Sound radiation, sound transmission, outdoor sound propagation and indoor sound fields, sound absorption materials, machinery noise and its control (fans, motors, compressors, air jets, pneumatic tools) and the design of sound enclosures.
The summer of 1974
Authors: Flatté Stanley M.
Published: October 2013

In the early 1970s, Garrett and Munk summarized oceanographers’ knowledge of ocean internal waves in a reference statistical spectrum. Almost at the same time, Hardin and Tappert introduced the parabolic equation into ocean acoustics. In the summer of 1974, Flatté and Tappert [J. Acoust. Soc. Am. 58, 1151–1159 (1975)] helped bring these two ideas together by simulating 100-Hz acoustic propagation through an approximate version of the Garrett–Munk spectrum to a range of 100 km, in order to help understand the effects caused by internal waves on acoustic fluctuations. The history of that summer will be discussed, along with a movie made at that time. The influence of that work on subsequent developments will be discussed.
Waves, rays, and the predictability of underwater sound fields
Authors: Brown Michael G.
Published: October 2013

Recent results relating to the application of ray-based methods to long-range underwater sound propagation are discussed, including Fred Tappert’s influence on the development of some of the ideas. Understanding limitations on predictability linked to chaotic motion of ray trajectories is a central issue. Related issues that are discussed include semiclassical breakdown and the important role played by the background sound-speed structure in controlling ray and wavefield stability. [Work supported by ONR.]
Can chaotic rays be used for long-range propagation?
Authors: Wolfson Michael A. , Henyey Frank S.
Published: October 2013

Fred Tappert was skeptical of the applicability of chaotic rays to long-range propagation experiments. In this talk, the best ray predictions we can make are compared to PE predictions. In particular, one expects the predictions of ‘‘deep arrivals’’ to be the most robust to uncertainties in how to use ray information, and the ray predictions fail to agree with the PE distribution of the intensity of the deep arrivals. The discrepancy can be seen in the propagation over the first 50 km from an assumed single mode source array. A comparison with a toy model shows that the difficulty with the rays is that the scattering is too weak, in the sense that almost all of the phase fluctuations in a correlation length are smaller than a cycle.
Low-frequency phase rate, source–receiver motion, and the parabolic approximation
Authors: Frisk George V. , Poole Travis L.
Published: October 2013

A theory relating the phase rate of low-frequency cw signals to the range rate between the source and receiver is presented. A key component of this theory is the parabolic approximation, which was introduced into underwater acoustics by Tappert. It is shown that, after shifting the received signal to the base band, the leading-order behavior of the residual phase rate is simply equal to the product of a typical wavenumber in the water column and the source–receiver range rate. This result holds true even for situations where the acoustic field magnitude clearly displays a complicated multimodal (or multipath) interference pattern. The theory is supported by a variety of experimental measurements obtained in a broad range of ocean environments. These include deep- and shallow-water situations, range-independent and range-dependent cases, and short- and long-range scenarios. Implications of the theory for phase tracking and localization of quasi-cw sources are also discussed. [Work supported by ONR.]