bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of sound environment characteristics: Comparative study between objective and subjective criteria
Authors: Chartier Francoise , Semidor Catherine
Published: October 2013

The evaluation of urban sound environment quality depends on quantitative information as well as the opinion of city dwellers. In order to underline the relation between objective and subjective points of view, a comparative study was carried out. The subjective survey consisted in listening to several binaural sound recordings of very short extracts from the urban scene, called ‘‘sonoscene.’’ During these sessions, the listeners’ opinions were noted. The binaural sound recordings are performed in accordance with the ‘‘soundwalk’’ method explained in previous papers [C. Semidor, ASA 2004, ASA 2005]. The same binaural sound recordings were analyzed in form of objective criteria such as Equivalent Sound Level, Loudness, Roughness, etc. This paper deals with the comparison between some of these objective criteria and subjective judgments such as Lack or Presence of traffic noise, Lack or Presence of human activities, Spatial Dimension, Attractiveness or Annoyance, etc. These first results point out some significant correlations between Loudness and Attractiveness for example, according to the nature of the sound sources (traffic, human activity).
Clayton H. Allen’s discovery of nonlinear acoustic saturation
Authors: Blackstock David T.
Published: October 2013

In 1950 Clayton H. Allen (1918–2004) discovered nonlinear acoustic saturation. His Penn State doctoral thesis, ‘‘Finite Amplitude Distortion in a Spherically Diverging Sound Wave in Air,’’ is about experiments on intense sound produced by a 12.2-cm diameter baffled piston vibrating at 14.6 kHz. At r=3.8 cm (the next-to-last nearfield peak) the maximum SPL produced was 161 dB (re 20 μPa). The farfield began at about 50 cm. Measurements were made of the fundamental and 2nd–6th harmonics out to r=200 cm. His received level versus source level curves at r=200 cm show the now familiar plateau that is reached as nonlinear effects limit the achievable SPL for a given distance at a given frequency. Clay’s discovery is quite remarkable because (1) it was totally unexpected and (2) it came long before any theoretical predictions of the phenomenon were developed. Alas, however, the work was never published except in the Army Signal Corps report from Penn State, ‘‘Atmospheric Physics and Sound Propagation, Final Report for Period July 1, 1945 to May 20, 1950,’’ and in two papers presented orally at the Penn State ASA Meeting in June 1950. As a result, Clay’s remarkable work has gone unappreciated for many years. This presentation is dedicated to his memory.
Numerical simulation of nonlinear phenomena using a dispersion-relation-preserving solution of the Navier-Stokes equations
Authors: Wochner Mark S. , Atchley Anthony A.
Published: October 2013

A modified Navier-Stokes equation set that includes classical absorption and molecular relaxation is solved using a fourth-order Runge-Kutta scheme in time and a fourth-order dispersion-relation-preserving algorithm in space. The algorithm is applied to examine nonlinear phenomena such as waveform evolution of a high amplitude sine wave to old age, shock coalescence, and evolution of arbitrary time waveforms. The results are compared to analytical solutions whenever possible. The drawbacks of such an approach are discussed along with possible solutions to problems associated with the numerical method.
Sensitivity to stimulus distribution characteristics in auditory categorization
Authors: Sullivan Sarah C. , Lotto Andrew J. , Newlin Elizabeth T. , Diehl Randy L.
Published: October 2013

Several experiments were performed to examine the ability of humans to categorize sounds as a function of training distribution characteristics. Participants were presented non-speech sounds randomly sampled from two overlapping distributions. The sounds consisted of 25 narrow-band noise bursts varying in center frequency from 1000–1360 Hz. Two conditions were created by varying the ratio of stimuli in each category (i.e., prior probabilities of each category), resulting in different ideal boundaries (maximizing accuracy). Participants were asked to categorize the sounds as either A or B and feedback was provided. In one experiment, prior probabilities were altered mid-session without alerting the subjects. Performance was tracked by plotting identification functions and noting boundary placement for each individual block. After only six blocks of training (∼35 min), most subjects had established optimal or near-optimal boundaries. Identification function slopes were calculated and found to be steeper than training distribution slopes; suggesting that listeners established criterion-like boundaries as opposed to performing probability matching. The fact that listeners adjusted their responses in accordance to distribution changes within relatively short periods of time demonstrates the perceptual systems effectiveness at optimizing categorization based on distribution characteristics. [Work supported by NSF and NIDCD.]
Effects of high-frequency amplification and training on impaired-listeners’ ability to discriminate redundant cues
Authors: Espinoza-Varas Blas , Bowman-Edmundson Shelagh , Jang Hyunsook
Published: October 2013

This paper examines effects of high-frequency amplification and training on the ability to discriminate redundant duration increments added simultaneously to the low (L) and high (H) frequency component of two-component complexes. The frequency of L (500 or 1000 Hz, 80 ms) and H (2000 or 3127 Hz, 60 ms) was chosen so as to stimulate simultaneously normal- and impaired-sensitivity regions of high-frequency sensorineural patients. The 3I/2AFC task displayed a standard followed by two comparisons. Duration increments in L, H, or both (tL, tH, or tLH), occurred randomly in comparison 1 or 2, and listeners had to decide which had an increment. The training stages were: (1) no H amplification, with L=35, H=−5 dB SL and tL, tH, and tLH; (2) H amplification, same as before but with H=35 dB SL; (3) H amplification and tH discrimination training, same as stage 2, but with tH only and H in isolation or together with L; and (4) retest of stage 2, post tH discrimination training. Only in stage 4 did redundancy yield a significant improvement in overall discrimination accuracy; amplification alone yielded little improvement.
Recognition of vowels that have been spectrally warped according to the frequency map for the spiral ganglion
Authors: Popolo Peter S. , Turner Christoper W.
Published: October 2013

The purpose of this study was to explore the effect of a specific spectral warping on vowel recognition in cochlear implant users. The warping was designed to simulate the misalignment of frequency-to-place stimulation which occurs if the spiral ganglion cells are electrically stimulated instead of the eighth-nerve dendrites in the organ of Corti. Simulated CIS-processed vowel stimuli were generated in which the analysis and carrier band center frequencies were shifted according to the projection of the spiral ganglion cells onto the organ of Corti, derived from published data [A. Kawano, H. L. Seldon, and G. C. Clark, Ann. Otol. Rhinol. Laryngol. 105, 701–709 (1996)]. Similar spectral warping was applied to unprocessed vowel stimuli. Listening experiments were conducted in which normal hearing subjects were presented with four types of stimuli: unprocessed-unwarped, processed-unwarped, unprocessed-warped, and processed-warped. For each condition, performance was allowed to stabilize over repeated trials with feedback, to allow for learning. Vowel recognition scores averaged across listeners were drastically reduced for the warped stimuli, regardless of whether the stimuli were CIS-processed or not. The combination of spectral warping and reduced spectral resolution resulted in the poorest intelligibility scores. These results may have implications for the design of frequency-to-place maps in cochlear implants.
Experiments on vibration absorption using energy sinks
Authors: Akay Adnan , Xu Zhaoshun , Carcaterra Antonio , Koç Ilker
Published: October 2013

This presentation describes experiments that demonstrate the concept of energy sinks where a set of multiple undamped linear oscillators attached to a vibrating structure can absorb most of its energy. In principle, energy sinks do not require presence of damping in the classical sense. A set of undamped oscillators that make up an energy sink collectively absorb the vibratory energy and retain it in their phase space. Earlier optimization studies by the authors have shown the feasibility of vibration absorption and retention by energy sinks if the set of oscillators have a particular frequency distribution. Experimental results support the concept of energy sinks. Different physical realizations of energy sinks demonstrate the significance of frequency distributions and the ability of energy sinks to reduce vibration amplitude of a primary structure to which they are attached.
Evaluation of effect of presbycusis on speech intelligibility by several kinds of speech test in rooms
Authors: Sato Hiroshi , Sato Hayato
Published: October 2013

Word recognition tests with logatom and word familiarity controlled word lists and sentence intelligibility test in simulated sound fields with noise and/or reverberation were carried out to assess the effect of hearing loss due to aging on speech communication in rooms. The result demonstrates that (1) speech recognition scores of elderly listeners are 25% lower than those of young adults for any kinds of speech test. This difference is equal to the 5 dB increase of ambient noise for elderly listeners. (2) Detailed speech recognition process in noise and/or reverberation is described with scores of various kinds of speech test. (3) Peripheral auditory functions are mainly affected by aging. On the other hand, central auditory processing functions of the aged examined with word familiarity and meanings of words shows same performance as the young. These results were expected to lead the discussion for speech communication in aged society and the standardization for sound environment.
Effect of training using lexically easy and hard words on speech understanding in noise
Authors: Burk Matthew H. , Humes Larry E.
Published: October 2013

Older hearing-impaired adults often have difficulty understanding speech in noise, even with proper amplification. One reason for this difficulty may be a lack of practice or inability to make use of new auditory information, which has been absent due to a progressive, peripheral hearing loss over many years. An often overlooked aspect of the rehabilitation process, which could help to improve this deficit, is listener training. The goal of this study was to create a word-based training protocol which could improve speech understanding in noise when listeners are presented with new, novel stimuli outside the clinic. Previous work with word-based training using one talker showed a large training effect that generalized to novel talkers; however, sufficient generalization to novel words and sentences was lacking. The current study attempts to increase generalization by training listeners with multiple talkers and lexically hard words. Generalization to novel words, both lexically easy and lexically hard, novel talkers, and sentences, with the latter also constructed from lexically easy and hard words, will be described. [Work supported, in part, by a research grant from NIA, R01-AG08293, awarded to the second author, and an NIH training grant.]
Variability of jaw movement in contrastive stress production of children with and without speech delay of unknown origin
Authors: Vick Jennell C. , Venkatesh Lakshmi , Moore Christopher A.
Published: October 2013

This study was designed to evaluate the control of jaw movement in contrastive stress productions of children with and without speech delay. The spatiotemporal index (STI) was used to calculate variability in jaw movement trajectories in 12 children producing three different metrical forms of CVCV syllables (trochaic, iambic, and even stress; papa, mama, and baba). The children (mean age: 3;2 years) were categorized, four in each of three groups, as having Normal Speech Acquisition (NSA), Speech Delay (SD), or both (NSA/SD) using the Speech Disorder Classification System (Shriberg et al., 1997). Results replicated findings in typically developing children of a similar age reported by Goffman and Malin (1999) where iambic forms were produced with greater stability than trochaic forms as measured by the STI. Analysis using a repeated measures ANOVA revealed significant effects for contrastive stress type, speech disorder classification, and syllable identity. Results are reported in the context of vowel acoustic measures of contrastive stress. [Work supported by NIDCD R01 DC 0000822-10.]
Articulatory movements during vowels produced by speakers with dysarthria and normal controls
Authors: Yunusova Yana , Westbury John , Weismer Gary
Published: October 2013

The central goal of the study was to provide a quantitative description of contributions of the jaw, lower lip, tongue blade and tongue dorsum to vowel productions, and to determine patterns of interarticulatory interactions between movements. Kinematic and acoustic signals were collected using the x-ray microbeam. Thirty-four speakers, 12 with dysarthria due to Parkinson disease, 7 with amyotrophic lateral sclerosis, and 15 normal controls, were recorded reading sentences at a comfortable speech rate. Ten CVC words, each containing one of the English vowels /i,I,u,a,ae,o/ carrying primary stress, were selected for analysis. Each fleshpoint trajectory was characterized by marker positions at vowel onset and offset, and the moment when speed was lowest. Measures of distance traveled, time to and from the moment of minimum speed, and peak and average movement speed were employed. Movement characteristics, and associations between movements, were compared for different vowels, contexts, speakers and groups. Results are reported for vowels and vowel groups (e.g., lax versus tense), averaged separately by contexts for speaker groups. The data speak to previous claims that speakers with dysarthria exhibit evidence of discoordination in speech movements relative to normal performance. [Work supported by NIDCD Award R01 DC003723.]
Signal to noise ratio loss and consonant confusions
Authors: Yoon Yang-soo , Allen Jont B.
Published: October 2013

Previous SNR loss (also called speech loss) studies showed that (1) SNR loss cannot be predicted from audiometric measures, (2) 40% of hearing aids wearers have 5 dB SNR loss or greater, and (3) SNR loss influences speech intelligibility significantly. These showed SNR loss to be important in speech recognition, but they do little, or no to illuminate the nature of consonant confusion, resulting from SNR loss. Thus, the goal of the current study was to investigate the effect of SNR loss on 16 consonants recognition in hearing impairment as a function of SNR. Confusion matrix data were collect and analyzed, and Fletcher’s AI was calculated from the SNR. These two measures were utilized (1) to determine how SNR loss was related to the event loss, (2) to test whether clustering of syllables in terms of consonant confusions was complied with SNR loss, and (3) to compare PI functions obtained from subjects and AI model. The results show that the degree of consonant confusion varies, but members of consonants confused with target sound above chance level are similar, as a function of SNR loss and SNR. It suggests that SNR loss limits recognition for specific consonants, even in noise.
Detecting small targets in strong bottom reverberation
Authors: Ren Jinyun , Bird John S.
Published: October 2013

The detection of small targets moving or appearing in heavy bottom reverberation is a challenging problem for surveillance sonars. Conventional detection techniques, such as variable thresholding, are inefficient because they require that the target return be large enough to compete with the total reverberation return. Based on a new reverberation model, this paper proposes a target detection scheme that provides target subclutter visibility in the presence of reverberation. First it is shown through experimental evidence that bottom reverberation as seen by a stationary sonar is coherent or at least partially coherent from ping to ping. Therefore reverberation for a particular range cell can be modeled as a complex signal composed of a stationary or slowing varying mean plus a rapidly varying diffuse component. This mean is easily estimated using an adaptive mean estimator and then removed so that the target need only compete with the diffuse component. Experimental results show that the detection gain over variable thresholding as measured by the coherent-to-diffuse ratio can be as much as 40 dB.
Channel effects on target characteristics in very shallow water
Authors: LePage Kevin
Published: October 2013

Very shallow water waveguides introduce channel effects which complicate the scattered response from objects. Here we model the effects of channel time spread and dispersion on the expected value of the time series backscattered by a sphere with and without uncertainty introduced by imperfect knowledge of the channel. We also model the predictable characteristics of the bottom reverberation against which detections are made. Results are intended to guide the design of dispersion and uncertainty-robust sonar systems in very shallow water. [Work supported by ONR.]
Separability of modal back-scattering matrix in shallow-water reverberation models
Authors: Wu Jinrong , Gao Tianfu , Shang Erchang , Ma Li
Published: October 2013

Normal mode model of the reverberation in shallow-water waveguides has been presented based on Born approximation. The key component of this model is the modal back-scattering matrix. Separability is one of the most important characteristics of the modal back-scattering matrix. The separability or quasi-separability of this matrix could make it easy for modal back-scattering matrix inversion. In this paper, the modal back-scattering matrix due to the roughness of the bottom interface in shallow-water was obtained and its separability error was analyzed. Numerical simulation shows that the separability error increases with modal grazing angle and density ratio of the sediment to the water, while decreases with sound speed ratio of the sediment to the water. It also shows that the effect of the separability error on shallow water reverberation level prediction is negligible. [Work supported by the National Science Foundation of China under Grant No 10474111.]
Auditorium Mundi soundscape in the narration of the world. Artistic and scientific aspects in the presentation of soundscapes
Authors: Brandt Harald
Published: October 2013

Auditorium Mundi is a project for the exploration and presentation of sounds and soundscapes of the whole world. The aim is an installation of a museum of audible perception in interrelation with other senses. The concept of the museum is an acoustic planetarium in which the locations of the world are put in place of the stars. Also located here are world archives for sound in which the acoustic and musical multitude of this planet will be preserved. The archives of sound are available world-wide through the internet. The museum is, at the same time, a laboratory for the development of new formats in scientific definitions and the multimedia presentation of acoustic phenomenons. It is a show-place for artistic programs and an auditorium where questions from the area of acoustic as well as new developments of industry will be accessible to a wider public. A place of innovation, where concepts for other museums, promoters and scientific institutions can be developed. The leitmotif of Auditorium Mundi is the question how man influences the soundscenes in which he lives and how strongly he himself is influenced by the noise, the resonance and the dissonance between various ways of life.
An L
Aeq is not an L
Aeq.
Authors: Botteldooren Dick , De Muer Tom , De Coensel Bert , Berglund Birgitta , Lercher Peter
Published: October 2013

Classical dose response relationships for environmental noise annoyance have been based on Ldn or Lden. These exposure measures are essentially based on an energy averaging measure, LAeq. Differences between groups of sources (e.g., continuous or event based) are accounted for by using separate dose-effect relationships. In society today, one often sees that event loudness is traded for number of events which is perfectly acceptable within the LAeq based annoyance concept. Clearly a more unified theory for noise annoyance is needed to fully account for the effect of such trade-offs. In this paper a model implementing such a theory is presented. The perceptual model starts from the premises that a sound event has to be noticed for it to contribute to overall annoyance. The model accounts for the fact that noticing a noise event not only depends on the level of the event itself but also on background noise, sound insulation and acoustic characteristics of the dwelling, level of attention, etc., the severity of the effect of a noticed sound on overall annoyance is assumed to primarily depend on the signal to noise ratio. The model allows to account for modifiers such as previous exposure, noise sensitivity, and coping. The model results are compared to the findings of a recent field experiment. Conclusions based on calculated and experimental trends will be presented.
Glottal-wave and vocal-tract-area-function estimations from vowel sounds based on realistic assumptions and models
Authors: Deng Huiqun , Ward Rabab K. , Beddoes Micheal P. , Hodgson Murray , Gick Bryan
Published: October 2013

Estimating glottal waves by inverse filtering vowel sounds and deriving vocal-tract area functions (VTAFs) from vocal-tract filter (VTF) estimates require that VTF models be realistic and that VTF estimates contain no effects of open glottises and glottal waves. In this study, VTFs are modeled to have lip reflection coefficients with low-pass frequency responses; to minimize the effects of open glottises and glottal waves on the estimates, VTFs are estimated from sustained vowel sounds over closed glottal phases, assuming that the glottal waves are periodically stationary random processes. Since incomplete glottal closures are common, VTF estimates may contain the effects of glottal loss. To eliminate the effects of glottal loss in the VTF estimates, lip-opening areas must be known. Theoretically, estimates of glottal waves and VTAFs corresponding to large-lip-opening vowel sounds are less affected by the glottal loss than those corresponding to small-lip-opening vowel sounds. The VTAFs and glottal waves estimated from vowel sounds produced by several subjects are presented. The normalized VTAFs estimated from large-lip-opening sounds are similar to that measured from an unknown subjects magnetic resonance image. Over closed glottal phases, the glottal waves are non-zero. They increase during vocal-fold colliding, and decrease or even increase during vocal-fold parting.
Categorization of spectrally complex non-invariant auditory stimuli in a computer game task
Authors: Holt Lori , Wade Travis
Published: October 2013

This study examined perceptual learning of spectrally complex nonspeech auditory categories in an interactive multi-modal training paradigm. Participants played a computer game in which they navigated through a three-dimensional space while responding to animated characters encountered along the way. Characters appearances in the game correlated with distinctive sound category distributions, exemplars of which repeated each time the characters were encountered. As the game progressed, the speed and difficulty of required tasks increased and characters became harder to identify visually, so quick identification of approaching characters by sound patterns was, although never required or encouraged, of gradually increasing benefit. After thirty minutes of play, participants performed a categorization task, matching sounds to characters. Despite not being informed of audio-visual correlations, participants exhibited reliable learning of these patterns at post-test. Categorization accuracy was related to several measures of game performance and category learning was sensitive to category distribution differences modeling acoustic structures of speech categories. Category knowledge resulting from the game was qualitatively different from that gained from an explicit unsupervised categorization task involving the same stimuli. Results are discussed with respect to information sources and mechanisms involved in acquiring complex, context-dependent auditory categories, including phonetic categories, and to multi-modal statistical learning.
Acoustic correlates of non-modal phonation in telephone speech
Authors: Yoon Tae-Jin , Cole Jennifer , Hasegawa-Johnson Mark , Shih Chilin
Published: October 2013

Non-modal phonation conveys both linguistic and paralinguistic information, and is distinguished by acoustic source and filter features. Detecting non-modal phonation in speech requires reliable F0 analysis, a problem for telephone-band speech, where F0 analysis frequently fails. An approach is demonstrated to the detection of creaky phonation in telephone speech based on robust F0 and spectral analysis. The F0 analysis relies on an autocorrelation algorithm applied to the inverse-filtered speech signal and succeeds in regions of non-modal phonation where the non-filtered F0 analysis typically fails. In addition to the extracted F0 values, spectral amplitude is measured at the first two harmonics (H1, H2) and the first three formants (A1, A2, A3). F0 and spectral tilt are measured from 300 samples of modal and creaky voice vowels, selected from Switchboard telephone speech using auditory and visual criteria. Results show successful F0 detection in creaky voice regions, with distinctive low F0, and statistically significant differences between modal and creaky voice in measures of spectral amplitude, especially for measures based on H1. Our current work develops methods for the automatic detection of creaky voicing in spontaneous speech based on the analysis technique shown here. [Work supported by NSF.]
The role of intonational phrasing in the elicitation of speech errors
Authors: Pouplier Marianne , Tiede Mark , Shattuck-Hufnagel Stefanie , Gao Man , Goldstein Louis
Published: October 2013

Recent work has proposed that some speech errors arise from an underlying coordination process in speech production in which gestures can assume grammatically illegal but dynamically stable coordination modes. The general premise is that shared gestural structure within a prosodic domain sets up the conditions under which stable coordination modes spontaneously emerge and produce errors. If certain gestures (e.g., coda consonants) recur every word but others recur less frequently (e.g., alternating initial consonants), the lower frequency gestures will increase in occurrence, resulting in gestural intrusion errors. This suggests that manipulation of the rhythmic domain through intonational phrasing should determine error patterns differentially. Since the gestural coupling which lies at the heart of the rhythmic synchronization approach takes time to establish, it is predicted that continuous repetitions of e.g. ‘‘cop tap tube cub’’ will lead to a maximum buildup of coupling strength and thus the most errors. If however phrasal grouping is imposed, as in ‘‘cop tap, tube cub,’’ fewer errors are hypothesized to occur. We test these predictions by having subjects repeat the same word string in different prosodic grouping conditions. Our initial results confirm that the more alternating consonants an intonational phrase contains, the more errors occur.
The role of stress accent in the understanding of sentences in noise
Authors: Divenyi Pierre , Brandmeyer Alex
Published: October 2013

When a target sentence is presented in noise, the stressed syllables therein will constitute epochs with a high likelihood of S/N increase. Since in spontaneous speech stressed syllables have significantly higher information content than unstressed syllables [S. Greenberg et al., in Proc. 2d Intern. Conf. Human Lang. Technol. Res. (2002), pp. 36–43], it follows that masking the stressed syllables will negatively impact the perception of neighboring unstressed syllables. This hypothesis was tested by varying the S/N of only the stressed syllables in sentences embedded in otherwise unmodulated speech-spectrum noise. Results suggest that, compared to conditions with absent or decreased-S/N stressed syllables, increasing the S/N during stressed syllables increases intelligibility of the unstressed syllable or syllables that follow. Since the unstressed syllables are rarely masked in the classic, energetic sense, the phenomenon reported constitutes an instance of informational masking. The masking can affect perception at the phonemic as well as on higher linguistic levels, depending on the information provided by sentence context.
Acoustic particle velocity and intensity calculations from tri-axial pressure gradient measurements
Authors: Austin Melanie E. , MacGillivray Alex O.
Published: October 2013

In July 2004 Fisheries and Oceans Canada supported a study to investigate effects of seismic airgun signals on hearing organs of freshwater fish in the Mackenzie River at Inuvik, NWT Canada. The study required particle velocity measurements for correlation with observed biological effects. JASCO Research built a pressure gradient measurement apparatus consisting of four hydrophones mounted at the vertices of a triangular-pyramid frame. The system was used to measure differential pressure from the airgun events simultaneously in three perpendicular axial directions. An attached depth-compass sensor monitored the depth and orientation of the system. Hydrophone separations were chosen to be small relative to the acoustic wavelength so that measured differential pressures correctly approximated the pressure gradients along each axis. Particle accelerations were computed directly from pressure gradients following Euler’s linearized momentum equation, and particle velocities were computed by integrating particle accelerations. Acoustic intensity was computed from the product of acoustic pressure and particle velocity. The hydrophone precision imposed a limit on accuracy of particle velocity measurements at low frequencies. Likewise the fixed hydrophone spacings defined an upper frequency limit for applicability of this method.
Speech intelligibility tests with real and simulated classroom noise sources
Authors: Kim Bumjun , Siebein Gary
Published: October 2013

Speech intelligibility tests using the MRT stimuli were administered to 13 college age students in actual classroom spaces in the presence of noise sources identified in a survey of 41 elementary school classrooms in 7 schools. Twenty two different noise sources were identified during the survey of schools in a local school district. A-weighted, C-weighted, octave band and 1/3 octave band measurements of 182 individual noise sources were recorded in the sampled rooms. Noise sources were categorized as students speaking, HVAC equipment, other building equipment, water running in sinks, computers, lighting fixtures, A/V equipment, and miscellaneous sources. The noise source measurements provide a useful data base for future classroom acoustical studies. Five noise levels (35, 45, 55, 65, and 75 dBA) of 4 different types of noise were tested in the rooms. The speech intelligibility tests found significant effects (at the 0.01 level) from level, spectra, type, content, and annoyance caused by the different noise sources. A predictive model based on these variables had an R2 of 0.90 for speech intelligibility under the extremely diverse set of conditions tested.
Optimal speech level for speech transmission in a noisy environment for young adults and aged persons
Authors: Sato Hayato , Ota Ryo , Morimoto Masayuki , Sato Hiroshi
Published: October 2013

Assessing sound environment of classrooms for the aged is a very important issue, because classrooms can be used by the aged for their lifelong learning, especially in the aged society. Hence hearing loss due to aging is a considerable factor for classrooms. In this study, the optimal speech level in noisy fields for both young adults and aged persons was investigated. Listening difficulty ratings and word intelligibility scores for familiar words were used to evaluate speech transmission performance. The results of the tests demonstrated that the optimal speech level for moderate background noise (i.e., less than around 60 dBA) was fairly constant. Meanwhile, the optimal speech level depended on the speech-to-noise ratio when the background noise level exceeded around 60 dBA. The minimum required speech level to minimize difficulty ratings for the aged was higher than that for the young. However, the minimum difficulty ratings for both the young and the aged were given in the range of speech level of 70 to 80 dBA of speech level.
Classroom noise and children learning in a second language
Authors: Nelson Peggy , Kohnert Kathryn , Sabur Sabina , Shaw Daniel
Published: October 2013

The presence of background noise affects children more negatively than adults. Understanding speech in noise is a skill that continues to develop well into a child’s adolescent years. Childrens’ experience with a specific language also may affect their ability to make sense of incoming speech. Research suggests that even for adults the presence of background noise negatively affects the ability to listen in a second language. Two studies were conducted to investigate the effects of classroom noise on attention and speech perception in native Spanish-speaking second graders learning English as their second language (L2), as compared to English-only speaking peers (EO). In Study 1 we measured childrens’ on-task behavior during instructional activities with and without soundfield amplification. In Study 2 we measured the effects of noise (+10 dB signal-to-noise ratio) using an experimental English word-recognition task. Findings indicate although there were no effects of amplification on on-task behavior, word-recognition performance declined significantly for both EO and L2 groups in the noise condition. In particular, the impact of the noise was disproportionately greater for the L2 group. Children learning in their L2 appear to be at a distinct disadvantage when listening in rooms with typical noise and reverberation.
Hearing impaired speech in noisy classrooms
Authors: Shahin Kimary , McKellin William H. , Jamieson Janet , Hodgson Murray , Pichora-Fuller M. Kathleen
Published: October 2013

Noisy classrooms have been shown to induce among students patterns of interaction similar to those used by hearing impaired people [W. H. McKellin et al., GURT (2003)]. In this research, the speech of children in a noisy classroom setting was investigated to determine if noisy classrooms have an effect on students’ speech. Audio recordings were made of the speech of students during group work in their regular classrooms (grades 1–7), and of the speech of the same students in a sound booth. Noise level readings in the classrooms were also recorded. Each student’s noisy and quiet environment speech samples were acoustically analyzed for prosodic and segmental properties (f0, pitch range, pitch variation, phoneme duration, vowel formants), and compared. The analysis showed that the students’ speech in the noisy classrooms had characteristics of the speech of hearing-impaired persons [e.g., R. O’Halpin, Clin. Ling. and Phon. 15, 529–550 (2001)]. Some educational implications of our findings were identified. [Work supported by the Peter Wall Institute for Advanced Studies, University of British Columbia.]
Integrating new technologies into split-beam riverine sonar systems
Authors: Dawson James
Published: October 2013

While development has continued on both acoustic hardware and data processing software, parallel development has involved integration of other technologies. Users may now access and control acoustic systems over the Internet or phone lines. Smart system software can perform self-diagnostics, alert remote users of system status, and automatically adjust operational and physical parameters (such as transducer orientation) during autonomous operation. In addition, advanced remote and autonomous systems are capable of real-time analysis and decision-making functions enabling near real-time decisions and automated interactions with a variety of devices, such as modems, Ethernet adapters, motor controls, and on-site electro-mechanical devices. Details and benefits of these advances are presented in a variety of case studies.
In vitro comparison of shock wave lithotripsy machines
Authors: Teichman Joel M. , Cecconi Patricia P. , Pearle Margaret S. , Clayman Ralph V.
Published: October 2013

We tested the hypothesis that shock wave lithotripsy machines vary in the ability to fragment stones to small size. Calcium oxalate monohydrate, calcium phosphate, cystine and struvite calculi were fragmented in vitro with the Dornier HM3, Storz Modulith SLX, Siemens Lithostar C, Medstone STS-T, HealthTronics LithoTron 160, Dornier Doli S and Medispec Econolith lithotriptors. Stones were given 2000 shocks or the FDA limit. Post-lithotripsy fragment size was compared. Struvite calculi were completely fragmented by all devices. The mean incidence of calcium phosphate dihydrate, calcium oxalate monohydrate, and cystine stones rendered into fragments greater than 2 mm was 0% for the HM3, Modulith SLX and Lithostar C, 10% for the STS-T, 3% for the LithoTron 160, 29% for the Doli and 18% for the Econolith (p=0.04); 0% for the HM3, Modulith SLX, Lithostar C, STS-T and LithoTron 160, 4% for the Doli and 9% for the Econolith (p=0.15); 1% for the HM3, 0% for the Modulith SLX, 1% for the Lithostar C, 10% for the STS-T, 14% for the LithoTron 160, 3% for the Doli and 9% for the Econolith (p=0.44), respectively. Shock wave lithotriptors vary in fragmentation ability.
Preliminary comparison of infants speech with and without hearing loss
Authors: McGowan Richard S. , Nittrouer Susan , Chenausky Karen
Published: October 2013

The speech of ten children with hearing loss and ten children without hearing loss aged 12 months is examined. All the children with hearing loss were identified before six months of age, and all have parents who wish them to become oral communicators. The data are from twenty minute sessions with the caregiver and child, with their normal prostheses in place, in semi-structured settings. These data are part of a larger test battery applied to both caregiver and child that is part of a project comparing the development of children with hearing loss to those without hearing loss, known as the Early Development of Children with Hearing Loss. The speech comparisons are in terms of number of utterances, syllable shapes, and segment type. A subset of the data was given a detailed acoustic analysis, including formant frequencies and voice quality measures. [Work supported by NIDCD R01 006237 to Susan Nittrouer.]
Modeling the acoustical and airflow performance of natural ventilation inlet and outlet units
Authors: Oldham David J. , Kang Jian , Brocklesby Martin
Published: October 2013

One aspect of the trend towards designing green buildings has been the increasing use of natural ventilation for buildings which otherwise might have required mechanical ventilation or even full air conditioning. However, the pressure differentials available to drive the natural ventilation process are small and hence relatively large inlets and outlets with low resistance to flow are required. These apertures constitute significant acoustic weak points on building facades and hence need to be treated to reduce noise ingress. Although there are a number of natural ventilation units available they have frequently been designed from the application of simple principles without any attempt to optimise both their airflow and acoustical performance. In this paper the results of a series of computer modeling exercises are described using acoustic FEM and BEM plus Computational Fluid Dynamics (CFD) which seeks to establish recommendations for the optimum design of natural ventilation inlet and outlet devices for both acoustical and airflow performance.
Measurements of the sound created by single bubbles fragmenting in turbulence
Authors: Deane Grant
Published: October 2013

One of the long-standing problems in wave noise is to understand the link between small-scale physical processes occurring in breaking wave crests and radiated noise. It has been known since the late 1980s that a broad-band component of wind-related noise comes from individual and collective bubble oscillations, but little progress has been made in quantative calculations of noise levels from whitecaps using first-principles physics. Recent theoretical and laboratory studies have demonstrated that at least part of the wave noise spectrum (from a few hundred hertz up to a few kilohertz) is generated by bubbles fragmented by the turbulent fluid flow in the wave crest. Results from some laboratory studies of the sound radiated by isolated bubbles fragmenting in a turbulent jet as a simplified model for fragmentation in whitecaps will be presented and discussed. [Work supported by ONR.]
Estimation of bubble density with subharmonic acoustic wave in bubbly water
Authors: Kim Byoung-Nam , Lee Kang Il , Yoon Suk Wang , Choi Bok Kyoung
Published: October 2013

Bubble density was estimated with a subharmonic acoustic wave generated in bubbly water. The subharmonic acoustic wave can be easily generated due to the nonlinearity of bubbly water if the frequency of primary acoustic wave is double of the bubble resonance frequency and the driving acoustic pressure amplitude exceeds a certain threshold value. The frequency of primary acoustic wave was varied from 200 kHz to 500 kHz while the bubble resonance radius at subharmonic frequency was from 12 um to 28 um. The pressure level of the subharmonic acoustic wave linearly increased as the driving acoustic pressure amplitude increased. With the subharmonic pressure level, the bubble density was estimated from nonlinear bubble oscillation equation [Yu. A. Ilinskii and E. A. Zabolotskaya, J. Acoust. Soc. Am. 92, 2837–2841 (1992)]. The estimated bubble densities were also compared with those from a linear conventional acoustic bubble sizing method. Bubble sizing with subharmonic acoustic wave seems to be easily utilized for the diagnosis of sandy sediment with bubbles.
Acoustical estimation of scatterer population from total scattering measurements
Authors: Conti Stephane G. , Roux Philippe , Demer David A.
Published: October 2013

Multifrequency backscattering measurements are more and more frequently used to estimate the populations of scatterers from echosounders data, and to separate the echoes from different species. Such analysis is based on the projection of the backscattered spectral data on the theoretical scattering spectra of the scatterers. Beside the accuracy of the theoretical predictions, the results of the inversion are conditioned by different parameters such as the ambient noise, the number of frequencies available, and the differences between the spectra for each scatterer. Here, we propose to evaluate the possibility of estimating the populations of scatterers from wide bandwidth total scattering cross section spectra measured in a reverberant media. The influences of the different parameters on the evaluated populations are investigated using simulations and experiments. Simulations were run either for similar spheres of different size, or different spheres of the same size. The experiments were performed in a reverberant tank with scatterers of different shapes having the same average total scattering cross section over the bandwidth.
The acoustic fields of shock wave therapy devices
Authors: Cleveland Robin O. , Chitnis Parag V.
Published: October 2013

We report measurements of a number of different shock wave therapy (SWT) devices. Two devices were electrohydraulic (EH): one had a large shock source (HMT Ossatron) and the other was a small hand-held source (HMT Evotron). The other device was a pneumatically driven device (EMS Swiss Dolorclast) and two different hand pieces were measured, one with an ‘‘unfocused’’ head and the other with a ‘‘focused’’ head. We found that the EH sources generated focused shock waves with a positive phase about 1 microsec long and peak pressure around 40 MPa, however, the acoustic output of the HMT Evotron appeared to be independent of the power setting of the machine. For the pneumatic source the duration of the positive phase was greater than 4 microsec and the peak pressure about 7 MPa. There was no clear shock front present and the waveform had a complex tail structure that was dependent on the power setting of the machine. We found that the focused hand-piece did not generate a focused acoustic field. The results are compared to reports of measurements from electromagnetic SWT devices. We contrast measurements made with different hydrophone systems: fiber-optic probe hydrophone, PVDF membrane hydrophone and PVDF bullet-shaped hydrophone.
Different shock front characteristics for non-urological treatments
Authors: Schultheiss Reiner
Published: October 2013

Focused shock waves: Concrement disintegration and stimulation of Pseudarthroses gaps request the shock wave energy at limited spatial areas. High pressure amplitudes and energies need to exceed certain thresholds of stone material for mechanical disintegration work. Accordingly the generation of fractures within the medullar bone explained the stimulation of healing proportional to the acoustic energy. Recent clinical findings reveal identical or even better outcomes at low number of shocks. Biological model: Accepting the biological model as promoted by W. Schaden, the peak pressure and the energy density of the shock waves might be lowered dramatically. Activation of the body’s healing mechanisms will be seen by ingrowth of new blood vessels and the release of growth factors. Unfocused shock wave sources: The biological model motivated the design of sources with low pressure amplitudes and energy densities. First: spherical waves generated between two tips of an electrode; and second: nearly even waves generated by generalized parabolic reflectors. Third: divergent shock front characteristics are generated by an ellipsoid behind F2. Unfocused sources are preferably designed for extended two dimensional areas/volumes like skin. Detailed acoustical parameters might be presented.
The mechanism of shock wave treatment in bone healing
Authors: Wang Ching-Jen
Published: October 2013

The purpose of this study was to investigate the biological mechanism of shock wave treatment in bone healing in rabbits. A closed fracture of the right femur was created with a three-point bend method and the fracture was stabilized with an intra-medullary pin. Shock waves were applied one week after the fracture. Twenty-four New Zealand white rabbits were randomly divided into 3 groups. Group 1 (the control) received no shock waves; group 2 received low-energy; and group 3 high-energy shock waves. The animals were sacrificed at 24 weeks, and a 5-cm segment of the femur bone including the callus was harvested. The specimens were studied with histomorphological examination, biomechanical analysis and immunohistochemical stains. The results showed that high-energy shock waves improved bone healing with significant increases in cortical bone formation and the number neovascularization in histomorphology, better bone strength and bone mass in biomechanics, and increased expressions of angiogenic growth markers including BMP-2, eNOS, VEGF and PCNA than the control and low-energy shock wave groups. The effect of shock wave treatment appears to be dose-dependent. In conclusion, high-energy shock waves promote bone healing associated with ingrowth of neovascularization and increased expressions of angiogenic growth factors.