bluuebunny/crossref_metadata_2025 huggingface dataset:
Quantal events generated by the structural and temporal variation of the vocal tract.
Authors: Story Brad
Published: October 2013

For connected speech, the time-varying vocal tract shape can be represented as a consonant superposition function that imposes constrictions and expansions on an underlying vowel substrate at specific points in space and time. The resulting flow of continuous speech sounds is a combination of characteristics of both the vowels and the consonants. A question is how speakers choose specific spatial locations and temporal patterns with which to execute particular consonants. In this study, acoustic sensitivity functions and formant nomograms based on a vocal tract area function model were used to determine the optimal locations for consonantal constrictions. Specifically, these techniques indicate the points within the vocal tract at which the acoustic effect of a constriction, in terms of formant frequency transitions, will rapidly change. These points are suggestive of quantal events that may occur during production of speech. [Work supported by NIH R01-DC04789.]
Leadership in Energy and Environmental Design for schools: Unintended consequences? Going “green” and the implications on classroom acoustics.
Authors: Norris Molly
Published: October 2013

The advent of the LEED for Schools Minimum Acoustical Performance criteria is a welcome step in the development of green building design. Recent experiences with trying to meet these criteria have led to frustration on the part of architects and the subsequent relaxation of the criteria by the USGBC into a more attainable structure. While the movement to incorporate green design is imperative, the relaxed acoustic criteria may actually be counterproductive in achieving a reasonable acoustic environment for learning. Has good acoustic practice been sacrificed for the green label and is it worth it? A recent case study will be presented.
A Leadership in Energy and Environmental Design study of Philadelphia Schools; What is old is new again.
Authors: Doggett Felicia
Published: October 2013

The Philadelphia School District has a stock of over 90 school buildings listed on the National Register that were constructed between 1920 and 1940, most of which are still in use today. With a minimum size of 50 000 sq ft per building, this resource of over 5×106sq ft of building area is likely to remain in use for at least another generation. The classrooms in the buildings are very similar in construction consisting of large windows, narrow floor plates, and concrete construction. The School District has also adopted the policy that every one of their new and renovated schools will be LEED certified under LEED For Schools 2007. Since it is not practical to raze these buildings, what can be done to meet the LEED certification? It is surprising how “green” they are. What is old is new again.
Vocal behavior of Florida manatees during vessel approaches.
Authors: Nowacek Douglas , Rycyk Athena
Published: October 2013

Florida manatees (Trichechus manatus latirostris) spend much of their lives in an “urbanized” ocean with high levels of vessel traffic being common during much of the year. To explore the detailed acoustic and motor behavior of manatees during vessel approaches, digital archival tags were attached to animals in the waters of southwest Florida in 2007 and 2008. These tags record sounds produced by the manatee and other sounds in the environment up to 32 kHz as well as sampling a suite of behavioral and environmental sensors at 50 Hz. The vocal behavior of manatees before, during, and after vessel approaches was investigated. Vocalizations were assigned to the tagged manatee by the higher amplitude and the presence of higher frequency harmonics compared to signals produced by nearby animals. Dolphins have been found to increase their vocalization rate at the onset of vessel approaches, and we have numerous vessel approaches to 20 individuals to evaluate manatee vocal behavior in these contexts. We will present results from single as well as multiple boat approaches and compare these vocal rates to periods without boats. In addition to reporting vocalization rates during vessel approaches, we are investigating the types of signals used by manatees in these situations.
Ultrasonic hearing and vocalizations are used in communication by West Indian manatee mothers and calves.
Authors: Gerstein Edmund , Gerstein Laura , Blue Joseph , Forsythe Steve
Published: October 2013

Ultrasonic hearing thresholds above 46 kHz were first measured with a test-sophisticated manatee in 1997. Using staircase and method of constants paradigms, pure tones (38–96 kHz) were presented in force-choice two-alternative tests. Repeatable detection thresholds were measured at 38, 46, 56, 66, and 76 kHz. These extended ultrasonic hearing results precipitated additional tests using the CHP-87-L acoustic tag, which regulatory biologists routinely attach to manatees. The tag produces a 75 kHz pulsed tone at 155 dB. The received SPL at manatee ears approximates 149 dB. Over a tag’s 2 year life expectancy, permanent selective hearing loss may occur. This is a concern because ultrasonic hearing may be important for directional hearing and communication between mothers and calves. Using a four hydrophone array, calls between wild mothers and calves were sampled at 100 kHz. Individual callers were localized, and some individuals could be identified. Peak source levels of 121 dB re 1 Pa at 2 m were directly recorded with significant energy (103 dB) at 46 kHz. These calls are highly directional and were only documented when manatee callers were positioned on axis with a hydrophone's acoustic center. Vigorous duets between calves and mothers had call rates up to 20 calls/min.
Sound source localization by the plainfin midshipman fish (Porichthys notatus).
Authors: Zeddies David , Fay Richard , Alderks Peter , Shaub Kiel , Sisneros Joseph
Published: October 2013

Sound source localization of the midshipman fish (Porichthys notatus) was studied using the phonotactic response of gravid females to synthetic advertisement calls. Playback experiments were conducted in a 12-ft-diameter outdoor concrete tank at the Bodega Marine Laboratory using a J-9 transducer placed at the center of the tank. The sound field in the tank was measured at 5-cm intervals using an eight-hydrophone array to measure the pressure gradients from which particle motion vectors were calculated. The acoustic measurements confirmed that the J-9 projector was operating as a monopole source. Animals were released 90 cm away from the sound source, and 60 positive phonotactic responses from naïve gravid females were video taped and analyzed. The phonotactic responses consisted primarily of straight to somewhat curved tracks to the sound source. Abrupt changes in trajectory to the sound source were rarely observed. The results confirm that fish can locate sound sources in the near field.
Acoustic wave characteristics of coarse and fine grain ground, frequency dependence of material properties.
Authors: Tavossi Hasson M.
Published: October 2013

Acoustic wave propagation in the ground with both coarse and fine grain materials is investigated. The distinction between the coarse and fine grains is made by the value of the wave number kd, where k is inversely proportional to the wave length and d is associated with the grain size. Wave velocity-dispersion and attenuation are studied at low- and high-frequency limits separately, that is, for kd values much greater and much less than 1, as well as for kd=1. It can be shown that the frequency dependence of elastic wave-velocity, dispersion, and attenuation are related not only to the grain-size and the nature of the contact areas, such as roughness and friction, but also these wave characteristics depend on the grain material. It can be shown that the grain material properties, represented by the elastic moduli, are frequency dependent. This frequency dependence of material properties in turn has effects on the ground wave behavior. Experimental and theoretical findings are presented to show these variations with frequency grain size and grain material. Among other applications, these findings on ground material elastic wave properties could be applied to the battlefield operations such as localization of the near surface explosions.
Development of a portable therapeutic ultrasound system for military, medical and research use.
Authors: Lewis George , Olbricht William
Published: October 2013

In the past two decades therapeutic ultrasound has obtained attention by the medical community as a tool to relieve arthritis, improve rehabilitation, and enhance wound healing processes. In the research realm, therapeutic ultrasound and its effects on tissue properties are currently being studied to great lengths. For example, researchers are assessing the ability of ultrasound for large molecule transdermal drug delivery, in targeted chemotherapy delivery to brain cancer, and cellular gene-transfer applications. Even though many applications of therapeutic ultrasound exist, the basic instrumentation has not changed much in the past 50 years. Here, we present a novel therapeutic ultrasound system we developed in our laboratory that is capable of producing acoustic power outputs well over the therapeutic range (greater than 50 W), lightweight (under 6 lb), portable (a foot print of 4×6×2 in.3), and rechargeable battery powered. The portable therapeutic ultrasound unit has the potential to replace plug-in medical systems and rf amplifiers used in research, both of which are bulky and burdensome. The portable system is capable of between-office and field service on its long lasting internal battery, making it especially useful for military, ambulatory, and house-call medical applications. [This research was supported by the National Science Foundation, National Institutes of Health, and Transducer Engineering Inc.]
Phased array for acoustic hail and warning.
Authors: McDevitt Timothy , Brungart Timothy , Barnard Andrew , Jenkins David
Published: October 2013

Background is given for the need of a high output acoustic hailing device (AHD) for military use. Those detrimental effects, which require high output power of an AHD, such as refraction, absorption, and insertion loss are briefly reviewed along with associated experimental data. The background for intelligibility is touched to address the importance of frequency response. A prototype phased array AHD, THOR, is then described and characterized via experimental results. [Work supported by the DOD.]
Is an impedance operator necessary causal, and is this an issue of complexity?
Authors: McCoy John J.
Published: October 2013

An impedance operator describes the mapping of a velocity field across a part of a boundary surface, to the traction field across the same part. Understood to represent the solution of a “direct” problem, i.e., the velocity field describes the problem forcing and the traction field part of the solution, the impedance operator is necessary causal. On the other hand, understood to represent the general solution of an “inverse” problem, i.e., the velocity field is part of the observed solution with the traction field representing the problem forcing, the operator need not be causal. Continuing, a uniqueness theorem that applies to the direct problem assures that the impedance operator thusly defined is unique. The lack of a corresponding theorem for the inverse problem suggests that the impedance operator thusly defined need not be unique. This further suggests requiring causality selects from multiple impedance operators, representing multiple solutions to the inverse problem, the one that is unique. This raises two questions. Is the causality that makes the operator unique a requirement of the governing physics? What impact does this have on the concept of impedance as a tool for addressing complexity in dynamical systems?
Formant lowering in spontaneous crying speech.
Authors: Erickson Donna , Shochi Takaaki , Kawahara Hideki , Rilliard Albert , Menezes Caroline
Published: October 2013

Acoustic and articulatory recordings were made at the EMA facilities of NTT Research Laboratories, Atsugi, Japan, for an American English speaker producing (a) spontaneous crying speech and (b) imitation of phrasing of the original crying speech, as control data. Articulatory analysis indicates differences in jaw, lip, and tongue positions for crying speech versus control speech. Acoustic analysis also shows that for crying speech compared with control speech, not only F0 increases but also higher formants tend to be lowered. Results of perception tests using the copy-synthesis program STRAIGHT (Kawahara) to morph a continuum of stimuli, keeping F0, duration, and intensity constant, suggest listeners to use cues of lowered formants to perceive emotional intensity of an utterance. Recent biophysiological modeling studies suggest that lowered formants may be due to a lowered larynx along with an expanded hypopharyngeal region [e.g., D. Honda, J. Acoust. Soc. Am. (1966); Kitamura et al., Acoust. Sci. Tech. (2004)]. This hypothesis as it applies to crying speech is currently being explored. [This work was supported in part by Japanese Ministry of Education, Science, Sport, and Culture, Grant-in-Aid for Scientific Research (C), (2007–2010): 19520371 and SCOPE (071705001) of Ministry of Internal Affairs and Communications (MIC), Japan.]
Phonetic status of Cj combinations in Korean and Spanish.
Authors: An Young-ran , Hwang Jiwon , Suh Yunju
Published: October 2013

Korean allows combinations of consonant and glide (CG) at onset position but forbids obstruent+liquid (OL) clusters. This is a potential problem for the universal sonority dispersion principle, which can be avoided if the Korean CG combinations are secondary-articulated consonants rather than clusters. To see if this hypothesis is phonetically supported, we compared Korean with Spanish, which allows both CG and OL onsets. F2 at the vocoid onset of (C)jV syllables varied as a function of the backness of the following vowel in Korean, whereas it stayed constant in Spanish. The vocoid duration increase from CV to (C)jV was also smaller in Korean. This shows that the Korean /j/ is weak in that it lacks a target frequency and its tongue position is decided by the following vowel. However, this property is not confined to the Cj combination, as CjV and jV syllables behaved in the same way. Our results thus support the idea that the Korean CG is close to secondary-articulated consonants, but the weak realization of /j/ is not a contextual variation after a consonant. One possible explanation for this pattern may come from the inherent property of CV coarticulation in Korean.
Acoustic variability and speaker discriminative power of liquids in American English.
Authors: Zhou Xinhui , Garcia-Romero Daniel , Espy-Wilson Carol
Published: October 2013

In American English, liquid sounds /r/ and /l/ are the most articulatorily variable and complex sounds. In previous work [Zhou et al., J. Acoust. Soc. Am. 123, pp. 4466–4481 (2008)], we found that the acoustic variability of /r/ due to two different tongue shapes (“retroflex” versus “bunched”) is reflected at the fourth and fifth formants. In order to understand how this articulatory diversity contributes to the intra- and interspeaker variabilities in speech signals of liquid sounds, an analysis of variance (ANOVA) analysis has been performed to investigate the intra- and interspeaker variabilities of liquid sounds across different frequency subbands. The Buckeye database was analyzed in this study, which includes about 30–60 min of broadband conversation speech for each of 40 speakers. The ANOVA analysis showed that liquids have the maximum F-ratios (interspeaker variance/intraspeaker variance) in the range of about 3–5 kHz, and /l/ has a larger maximum F-ratio than /r/. In general, liquids have larger F-ratios than stops and fricatives and have smaller F-ratios than vowels and nasals. The results of phoneme-based speaker identification task will be presented to show the speaker discriminative power of liquids along with the results for other phonemes such as vowels and nasals.
Final consonant voicing and vowel height contrasts in whispered speech.
Authors: Gilichinskaya Yana , Strange Winifred
Published: October 2013

Whispered speech is a naturally distorted speech signal. Whereas it preserves some characteristics of fully phonated speech, some important acoustic cues are removed, diminished, or altered. The prominence of acoustic cues in whispered speech may change due to the physical properties of the whispered speech signal, i.e., decreased intensity, the absence of periodic vibration of the vocal folds, damping of F1, shift of the formants, and flattening of the amplitude envelope. Such changes affect the acoustic cues both for vowels (e.g., vowel height) and consonants (e.g., voicing contrasts). The objective of the present project was to explore the acoustic cues for poststressed syllable-final consonant voicing contrasts and the vowels preceding them in continuous whispered speech of American English speakers and to compare the results with those in fully phonated speech. The stimuli were recorded in the carrier sentence “I’ll utter /habVC/ off the list.” The consonant pairs included voiced/voiceless bilabial stops /b-p/ and labiodental fricatives /f-v/, each combined with 11 AE vowels /i, εe, æa, ʌo, ɔu/. Preliminary results showed that vowels had longer duration in whispered speech than in fully phonated speech. Spectral dispersion, temporal contrastiveness of vowels, F1, and vowel duration cues will be reported in the presentation.
Acoustic characteristics of sonorant consonants.
Authors: Allen Phoebe , Fourakis Marios , Weismer Gary
Published: October 2013

This is a report on the acoustic characteristics of sonorant consonants in Midwestern American English. Ten speakers (five male and five female) of south central Wisconsin origin were recorded producing these consonants. The sonorants [l,r,m,n] plus the velar nasal, when possible, were elicited in the word initial, medial, and final positions. In the initial and final positions, the immediately adjacent vowel varied over three different stressed vowels. In the final position, the sonorants also occurred postconsonantally, as in the word bottom resulting in their syllabic versions. All but 4 of the 37 words used were real words. Five repetitions of each word were recorded. Measurements of durations, amplitudes relative to the adjacent stressed vowel, the first three formants at the halfway point of each sonorant, and of the first antiformant for the nasals will be presented. In addition, formant transitions were tracked going into and/or coming out of the sonorant consonant and will also be presented and discussed. [Research supported by UW-Madison Graduate School.]
The effect of talker image on phonetic convergence.
Authors: Babel Molly
Published: October 2013

This paper reports on an experiment that examines the socially motivated status of phonetic convergence. This is done by comparing social and asocial conditions in a lexical shadowing task. The social condition includes a photo of the talker while the asocial condition does not. The lexical shadowing task consists of the presentation of 50 low-frequency monosyllabic words with the vowels /i ae a o u/ six times each. Participants are also recorded reading the word list in pretask and post-task readings. Acoustic analyses are underway to identify differences in level of phonetic convergence in participants' productions in the two conditions (n = 20 in each condition) by comparing productions in the shadowing task to the pretask base line recordings. The results of this experiment contribute to the discussion regarding the status of phonetic convergence as a socially motivated process or a natural reflex that stems from the relationship between speech perception and speech production. This work has clear implications for theories of language change in addition to addressing issues regarding exemplar-based theories of speech production, the relationship between speech perception and production, and the perception and encoding of talker-specific characteristics.
Impulse response and acoustic fluctuation of high-frequency signals in a shallow water estuary.
Authors: Radhakrishnan Sreeram , Sutin Alexander
Published: October 2013

Measurements of channel impulse response and its fluctuations in shallow water areas can be used for the prediction of sonar performance, the estimation of active and passive acoustic diver detections, and the prediction of channel characteristics relevant to underwater communication. A shallow water high-frequency propagation experiment was conducted in the Hudson River near Hoboken, NJ by the Maritime Security Laboratory at Stevens Institute of Technology. Acoustic propagation from an omnidirectional emitter to a receiver was investigated in the frequency band from 20 to 100 kHz for distances up to 100 m in a water depth of 8 m. Frequency sweep signal application was allowed for optimal analysis of the channel impulse response in a wide frequency band. Eigenrays corresponding to direct, surface-reflected, and bottom-reflected arrival paths were traced using the BELLHOP program. The fluctuation statistics of narrowband impulse responses for direct, surface-reflected, and bottom-reflected arrivals in different frequency bands was estimated. It was found that signals corresponding to the surface-reflected arrival show considerably higher temporal variation than direct and bottom-reflected arrivals. Comparison of impulse response for near-surface and near-bottom source depths indicates that the bottom-reflected arrival undergoes significantly high attenuation. [Work supported by ONR Project N00014-05-1-0632: Navy Force Protection Technology Assessment Project.]
Stretched, perforated, and auralized: A case study of integrating acoustic treatment into the modern museum to control sound propagation and room acoustics.
Authors: Biziorek Ryan
Published: October 2013

Modern museum designs typically require exhibits with AV components. The museum spaces must also be flexible for various types of internal and external events. While the current architectural trend to use glass, concrete, and other sound reflecting materials presents acoustic challenges, there are various techniques to integrate a sound absorbing treatment into a museum facility to allow for flexibility and control of room acoustics. Using materials integrated into multifunction architectural elements, acoustic treatment can be seen as a necessary element within a space. Further modeling and auralization can help the client understand the amount and necessity of an acoustic treatment within various museum spaces. Two case studies will be presented as to how acoustic treatment can be incorporated into the architectural design and use auralization to allow the client to be involved in the acoustic design process.
Categorization of budgerigar (Melopsittacus undulatus) warble elements.
Authors: Tu Hsiao-Wei , Smith Edward , Dooling Robert
Published: October 2013

The warble song of budgerigars is composed of a variety of elements without any obvious sequential order. Some of the elements also occur as single utterances. A previous study classified warble elements into 42 groups by visual inspection of spectrograms. However, the density of warble (about 140 elements/min, up to 30 min in duration) makes this method both laborious and time-consuming for analyzing a large amount of warble. Here three human raters took 860 elements from 3 birds and sorted the sonograms into 9 general groups with an inter-rater reliability of 89%. Next, these elements were used to train a neural network. This network learned to categorize a large number of warble elements efficiently with 84% reliability (compared to human raters). Further examination of other warble streams revealed that warble elements are not evenly distributed across these nine groups for the same bird, but the relative proportion of different elements in warble categories is similar across three budgerigars. Ongoing studies are examining whether birds vary the proportion of elements in different social contexts to better understand the biological function of this complex vocalization. [This work is supported in part by DC-00046 and DC-00198 to R.D.]
The effect of social and environmental manipulations on the vocal response rate of budgerigars (Melopsittacus undulatus).
Authors: Marvit Peter , Payne Zach , Ratner Adam , Dooling Robert
Published: October 2013

The budgerigar (parakeet) exhibits complex social interactions and relationships. This project investigates the budgerigar “contact call” that is used for both local and distance social cohesion. It is hypothesized that budgerigar vocal response rates will vary with the social “distance” of the caller (e.g., mates greater than conspecific strangers) and that overall rates will increase as the background acoustic environment becomes more complex and naturally rich. To test these hypotheses, vocal response rates of budgerigars were measured to four groups of recorded contact calls, within four acoustic environmental contexts. Three mated pairs were subjects. The results showed huge individual differences. Overall, males responded significantly more than females. There was a trend toward greater responses to mates than self, flockmates, or strangers. There were a large and significant response increases during a familiar flock background and significant decreases during silence. The response vocalizations themselves were analyzed for possible patterns to the different auditory contexts. The results are consistent with a hypothesis of social facilitation, although the individual differences pose a curious problem that a larger sample size may help elucidate. [Work supported by NIH/NIDCD 5R01DC000198 and 2P30DC004664.]
Numerical analysis of flapping sound generated by hovering insects.
Authors: Inada Yoshinobu , Aono Hikaru , Liu Hao , Aoyama Takashi
Published: October 2013

Insect flapping sound is a consequence of flow disturbance generated by flapping wing motion. Spatial and temporal changes of pressures on the wing surface and vortex structures generated by the wing motion are considerable sources of the flapping sound. To analyze such mechanism in the sound generation, we have developed an integrated method combining computational fluid dynamics (CFD) techniques and acoustic analysis. Unsteady flows around a hovering insect are simulated by NS solution-based CFD analysis with a multiblocked, moving-overset grid technique. In the acoustic analysis, monopole and dipole sound sources generated by the wing motion are analyzed by using Ffowcs–Williams and Hawkings method. In this study, numerical analyses of the flapping sounds are carried out for three insects of hawkmoth, honeybee, and fruitfly. The CFD analysis provides a detailed picture of the flow fields around the hovering flyers where complicated vortex aspects and the induced pressure distributions on the wing surfaces show concrete evidence of the sound sources. The acoustic analysis further clarifies the characteristics of the flapping sounds induced by these sound sources, including the sound directivity and its spectrum distribution. These results effectively demonstrate the cause-and-effect relationship in sound generation and thus indicate the availability of this integrated CFD-acoustic method.
Outdoor pulse echo speed of sound measurement for all ages.
Authors: Sabatier James M. , Sabatier Charles H. , Taylor Celeste S.
Published: October 2013

One of the major thrusts of ASA Vision 2010 is to develop education outreach for a spectrum of learners from kindergarten students to senior citizens. Along these lines we explore a simple speed of sound measurement that can be accomplished by this broad range of learners. Understanding slow speed of sound compared to the speed of light allows the learner to comprehend the lack of temporal/optical correlation between sound and position of airplanes as they move across the sky. Other examples include the late arrival of sounds from aerial salutes during firework displays and sounds of lightning during storms. Synchronizing the acoustic echo of a sound pulse from an outdoor wall with the pulsed source for several duty cycles allows sound speed measurements. Analysis of the time of arrival with distance is presented for various wall sizes and air temperatures. The successes of the learning exercise and results of the measurements when accomplished by the K-gray audience will be presented (see, for example, http://arts.ucsc.edu/EMS/Music/tech_background/TE-01/soundSpeed.html).
Modeling local stationarity in speech wave forms.
Authors: Rudoy Daniel , Basu Prabahan , Wolfe Patrick J.
Published: October 2013

Typical speech wave forms are well modeled as slowly time-varying, or so-called locally stationary, stochastic processes. This talk outlines recent work in detecting and modeling locally stationary speech time series, and describes a new method of adaptive short-time Fourier analysis and reconstruction based on local measures of time-frequency concentration. While adaptive analysis measures have previously been proposed in order to overcome the limitations of fixed-resolution schemes, the scheme presented here derives from quantifiable and rigorous notions of local stationarity. This yields demonstrable robustness properties for the case of noisy speech, as well as improved mean-square error estimation properties and other quality improvements relative to standard estimation procedures in which time-frequency resolution is fixed. [Work supported in part by DARPA and NSF.]
Neighborhood indicator based on tonality and arrangements in musical organization: Automatic system for selecting similar excerpts based on musical information.
Authors: Yamakaji Yuichiro , Miura Masanobu
Published: October 2013

Recently, various methods for searching similar musical excerpts have been studied. However, it has not yet been realized that a method of automatically selecting similar excerpts based on features was obtained from musical information in consideration of a music theory. Therefore, this study was to realize the method. Concretely, employed parameters are “chord trigram,” modeling sequence of chords based on the n-gram model, “emotional parameter,” corresponding to emotional expressions such as tempi, modes, and average of duration for melody, and “note density,” corresponding to the occurrence frequency of notes. Excerpts dealt with here are grouped into several categories based on proposed parameters by the CART algorithm, and degree of similarity is calculated between excerpts in each category. Developed here is a system for automatically selecting similar excerpts based on features obtained from musical information, named “NITAMO,” which stands for neighborhood indicator based on tonality and arrangements in musical organization. The new system deals with more than 5400 excerpts and employs the XF format, a commercially sold format as an extended form of MIDI. We confirmed that the proposed system was useful by comparing similar musical excerpts provided by proposed system with those by human. [Work supported by the HRC, Ryukoku Univ.]
Measurement of the ambient in relocateable modular classrooms.
Authors: Schomer Paul , Chang Wilbur , Derks Irvin
Published: October 2013

The ambient in a classroom consists of noises internal to the classroom (e.g., HVAC, lighting, IT equipment, refrigerators, and fish tank pumps) and noises external to the classroom (e.g., street traffic, aircraft, children in the playground, and adjacent classroom noise). Currently, ANSI S12.60, Classroom Acoustics, requires that the A-weighted ambient level, unoccupied, be less than 35 dB at the noisiest position in the classroom. A basic reasonable procedure to implement the required measurements has been developed and tested. The authors find that the procedures developed can be readily used by inexperience but technically oriented individuals. The procedure separates the measurement of internal and external noises into two measurements, typically at different positions. Because the two noises are variable, unrelated in position, and uncorrelated in time, it does not make sense to combine them in any fashion. Rather, in the procedure to be recommended by WG 68, the two measurements are to be reported and evaluated, separately, against the 35 dB criterion. Other notable changes are expansion of the measurement hours to include busy traffic periods (high environmental noise periods) prior to and after school and on Saturdays, and implementation of HVAC duty cycles to better estimate a typical A-weighted hourly equivalent level from HVAC equipment (the subject of a companion paper).
Comparison of time-integration schemes for fluid-structure interaction.
Authors: Ferri Aldo A. , Kapacee Mohammed , Ginsberg Jerry H. , Smith Marilyn
Published: October 2013

Computational structural-dynamics codes invariably use finite element (FE) methods and relatively course meshes, whereas finite-difference methods with fine meshes are popular for modeling the fluid domain. Fluid-structure interaction (FSI) problems in which there is a mean flow feature can be addressed by simultaneously employing both techniques. Because of the dissimilarities of the two formulations, a time-domain solution is most readily obtained by allowing each code to march forward in time in a loosely coupled manner. A proper FSI implementation must address the physical and computational issues associated with compatibility of displacements and surface tractions at the boundary of the two domains. It is also necessary that one identifies a suitable numerical scheme to perform unsteady time-marching simulations of the coupled system. It is the latter issue that concerns this paper. Various techniques for accurate and stable time integration of loosely coupled systems are compared. A two-dimensional example is studied that consists of an inviscid compressible fluid and a thin elastic beam/plate. Small amplitude motion is assumed for the plate, so linear approximations are used in the FE model. The fluid domain, on the other hand, is modeled using the nonlinear Euler equations. [Work supported by NASA Contract No. NAS1-02117, Task Order 6101-GT.]
Coupling of extensional and flexural displacement fields in straight bars.
Authors: Ginsberg Jerry H.
Published: October 2013

Extensional and flexural displacements of straight elastic bars are conventionally treated as independent superposable effects. However, coupling of displacement fields due to boundary effects is an important feature in many realistic configurations. The present paper examines the vibration modes of a beam in which the aforementioned coupling is caused by a roller support that is mounted on an incline. A closed form solution of the coupled dislacement modes is derived. The transcendental characteristic equation is shown to depend solely on the incline angle for the end support, the reduced frequency formed from the bar wave speed, and the ratio of the cross-section’s radius of gyration to the span length. The characteristic equation is solved numerically. The resulting eigenvalues are used to evaluate the coupled mode shapes, which leads to a quantitative assessment of coupling effects relative to the limiting cases where the incline is horizontal or vertical, for which the displacement fields truly are uncoupled. An interesting aspect of the analysis is its mathematical similarity to the application of Timoshenko theory to bars.
Speech enhancement for noise-robust speech recognition.
Authors: Mitra Vikramjit , Espy-Wilson Carol
Published: October 2013

A modified phase opponency (MPO) model was combined with the aperiodic/periodic/pitch detector (APP) by Deshmukh et al. [JASA, 121, 3886–3898 (2006)] for speech enhancement. The MPO-APP passes the speech-dominated regions as is but greatly attenuates the noise-dominated regions. Thus, the noise in nonspeech regions and in the regions between the formants are significantly reduced. Unlike many other techniques, the MPO-APP does not introduce musical noise. However, given that the noise in formant regions is passed along with the speech signal, the enhanced signal sometimes has a shadow effect. To get rid of this shadow effect, we recently developed a preprocessor for the MPO-APP. First, the signal to noise ratio of the signal is estimated. Second, we use an adaptive generalized spectral subtraction technique to reduce the noise in the speech dominant regions. The results show a significant improvement in the quality of the enhanced signal and, in addition, increased accuracy in automatic recognition of the enhanced signals over that obtained from the original signals or the signals enhanced without the preprocessor. [Research supported by NSF Grant IIS0703859.]
Modeling prosodic rhythm: Evidence from second language speech.
Authors: Nava Emily , Goldstein Louis , Nam Hosung , Proctor Michael , Saltzman Elliot
Published: October 2013

The global prosodic structure of languages has been described using the typological dichotomy of stress-timed versus syllable-timed. Various indices have been successfully employed in literature for quantifying these classifications, one of which is the duration ratio between the total voiceless and total voiced stretches in the signal. It has been further shown that various language-specific characteristics, such as syllable-structure phonotactics and stress-sensitive lengthening and shortening, can contribute to this difference. To reveal the interaction of these components, acoustic data from running speech of L1 Spanish/L2 English and native English speakers were analyzed. Total ratio of voiceless-to-voiced durations discriminated L1 Spanish (lower) and L1 English (higher); L2 speakers showed ratios in between the two, with higher proficiency L2 speakers showing ratios closer to L1 English. A task dynamic application, a speech planning and production model [Nam et al., J. Acoust. Soc. Am. 115, 2430 (2004)] was used to model the performance of the L1 and L2 speech of L2 speakers, allowing determination of which contributors to global rhythm are more readily acquired by L2 speakers. [Work supported by NIH and NSF.]
Reconstruction of missing formants based on spectral power series expansion.
Authors: Minemura Kesaaki , Goto Satoru , Tohyama Mikio
Published: October 2013

In this paper, we investigated spectrum estimation for vowels using power series expansion. In general, sound signals can not keep their characteristics when the spectral peaks and dips are missing. Consequently, the missing spectral peaks and dips are estimated by using power series expansion. First, vowels are divided into cycle by cycle. Second, the one-cycle vowels are converted into frequency by FFT. Third, damaged spectra were made for demonstrating spectrum estimation. Fourth, we estimated missing spectral peaks and dips using power series expansion. In our spectrum estimation, the differential coefficients for power series expansion were calculated from nearby spectrum of missing spectrum. In this experiment, the estimated spectrum was almost the same compared with the original spectrum in the case of approximation by power series expansion on the rank of 6. The spectrum is restored about the range of 180 Hz using nearby 10-Hz samples. Consequently, power series expansion can estimate spectral peaks and dips for recovering spectrum.
Experimental and numerical determination of the surface deformation of a synthetic model of the human vocal folds.
Authors: Chen Li-Jen , Mongeau Luc
Published: October 2013

A model of human vocal folds was fabricated using a three-component liquid platinum-catalyzed silicone solution. The size, idealized shape, and mechanical properties of the homogeneous synthetic model were selected based on the available data. The superior surface displacement of the synthetic model during self-oscillations was measured using the digital image correlation technique. A finite element model of the synthetic model was created to calculate the state of the deformable solid. Modal testing of the synthetic model was performed to establish the material properties and to verify boundary conditions in the simulation. The self-oscillation of the synthetic model was simulated by imposing a sinusoidal pressure loading over model surfaces, with frequency and amplitude determined from the direct measurement. From the simulation, the von Mises stress over the inferior surface was found to be around 2.2 kPa during the maximum orifice opening, which is around twice of that over the superior surface. So far, only the superior surface deformation data have been available because of technical limitations in clinical studies. The current study may provide additional information, such as the maximum amplitude and location of the peak stress, which is useful for diagnostic and treatment purposes. [Work supported by NIH.]
Effects of multiple contacts on cued beamforming in active-passive data fusion.
Authors: Yudichak T. W. , Yocom Bryan A.
Published: October 2013

Active-passive data fusion seeks to combine the information measured on multiple sonar sensors to detect and track contacts more effectively than is possible with individual active or passive sensors. One way in which sonar signal processing can benefit from data fusion is cued beamforming, the allocation of beamforming resources based on the current estimate of the location of a contact. Cued adaptive beamforming (ABF) on passive arrays has been shown to provide more precise direction-of-arrival estimates than standard ABF in some circumstances involving a single contact of interest. At the same time, the performance of cued beamforming in directions away from the contact can be severely degraded relative to standard beamforming, resulting in the possible loss of detection of other contacts. This talk investigates the trade-offs between the gain in information on a single contact and the loss of information on other contacts when cued ABF is applied to passive arrays within a multisensor data fusion framework. The effectiveness of cuing different arrays with different contacts as well as alternating between standard and cued beamforming is examined and discussed. [Work supported by ONR.]
Statistics of synthetic aperture sonar image resolution degradation.
Authors: Johnson Shawn F. , Lyons Anthony P. , Abraham Douglas A.
Published: October 2013

Synthetic aperture sonar (SAS) image statistics can often be characterized by a probability density function with a heavier tail than the expected Rayleigh distribution. The K-distribution shape parameter can be used as a metric of non-Rayleighness, with physical ties to both seafloor properties and sonar parameters. Recent results have shown that increasing the resolution cell size, or degrading the resolution of the image, produces images with statistics tending toward Rayleigh (i.e., a higher K-distribution shape parameter). In general, a doubling of the resolution cell area results in a doubling of the K-distribution shape parameter. A caveat to this generalization is the orientation of the sonar system to any features that may exist on the seafloor (i.e., sand ripples). In such a situation, image statistics may continue to be significantly non-Rayleigh for certain orientations in spite of resolution degradation. SAS images of seafloors with various bottom types and feature orientations collected with an AUV by the Naval Surface Warfare Center Panama City Division have been postprocessed to analyze changes in image statistics as the image resolution is degraded. Results of the image degradation on statistics will be discussed. [Work supported by ONR Grant Nos. N00014-04-1-0013 and 1N00014-06-1-0245, and Code 32.]
Monte Carlo simulation of rough surface scattering using a modified pseudospectral time-domain method.
Authors: Ha Yonghoon , Lee Keunwha , Seong Woojae
Published: October 2013

A pseudospectral time-domain (PSTD) method using a surface flattening transformation and image method is applied to a randomly rough pressure-release surface scattering problem. Above, the PSTD method efficiently avoids the Gibbs phenomenon appearing in the conventional PSTD method when treating irregular boundaries with large impedance contrast. The pressure-release surface is generated by Pierson–Moskowitz spectrum and Monte Carlo method is used to calculate the statistical properties of the rough surface. The Monte Carlo results for elemental scattering area will be investigated by comparing with Chapman–Harris formula.
Atlantic herring low-frequency target strength and abundance estimation: Ocean acoustic waveguide remote sensing (OAWRS) 2006 Experiment in the Gulf of Maine.
Authors: Gong Zheng , Andrews Mark , Cocuzzo Daniel , Dasgupta Saumitro , Ratilal Purnima , Jagnnathan Srinivasan , Symonds Deanelle , Bertsatos Ioannis , Chen Tianrun , Makris Nicholas , Nero Redwood , Pena Hector , Patel Ruben , Godoe Olav Rune , Jech J. Michael
Published: October 2013

The mean low-frequency target strength (TS) of spawning Atlantic herring populations in the Gulf of Maine is estimated from the experimental data acquired during September–October 2006 near the northern flank of Georges Bank. A low-frequency OAWRS system with an instantaneous imaging diameter of 100 km was deployed to provide spatially unaliased imaging of fish populations over wide areas. The OAWRS system’s scattering strength measurements are calibrated with areal fish population density estimates obtained from concurrent localized line-transect measurements with several conventional fish finding sonars (CFFSs). Trawl sampling at selected locations enables the identification of the imaged species. The mean TS estimates of herring individuals exhibits significant variation over OAWRS operating frequency range, in accordance with the results from a resonant scattering model for swimbladder-bearing fish. The neutral buoyancy depth of herring and the species composition in the imaged population is inferred by comparing the measured TS with those derived from the model. Our analysis indicates that the herring population has a neutral buoyancy depth of between 70 and 90 m and is therefore negatively buoyant between 120 and 180 m water depth at which it is commonly found. The herring populations instantaneously imaged with OAWRS often exceeds 200×106, of which over 150×106 individuals can be organized into a large shoal.
Classroom acoustics: A first step toward education for all.
Authors: Anderson Karen L.
Published: October 2013

Education is primarily provided through the medium of verbal instruction. With ever greater emphasis on test scores and teacher accountability, it is important to recognize the effects of excessive background noise and reverberation on student learning. Nixon was a leader in the movement to raise awareness of classroom acoustic effects and to achieve national written standards. He crossed professional lines to become an active member of the Educational Audiology Association, providing information and advice to almost 1000 audiologists who work for U.S. school districts. Nixon was instrumental in not only raising awareness, but raised the bar for what education audiologists should know about classroom acoustics. This paper will provide information on the listening challenges of learners with hearing loss (the most common birth defect), most of whom are educated in typically noisy classrooms. Acousticians are invited to learn more about the synergistic effects of excessive noise and reverberation on speech perception of this growing number of children and what the hearing industry is doing to address these issues. Together, the voices of the acoustics and hearing industries are needed to champion the case for listening, learning, and a better future footsteps left by Nixon.
Graphical representation of acoustic data.
Authors: Ermann Michael , Victor John Samuel
Published: October 2013

This line of research aims to graphically represent acoustic data for clear comparisons. With a particular focus on low-frequency sound absorption, noise reduction coefficient, and impact insulation class, acoustic data are presented visually and grouped. Trends emerge when looking at some data, and in other cases similar assemblies may have dissimilar acoustic values.