bluuebunny/crossref_metadata_2025 huggingface dataset:
An acoustics education outreach program for young children
Authors: Muehleisen Ralph T.
Published: October 2013

With limited time for science in the preschool and primary classroom, and limited science education of many preschool and primary school educators, the need for science professionals to engage in outreach education is ever increasing. Additionally, there is an increasing need for children to be aware of the problems of noise exposure, especially with regard personal sound systems. In this talk, a one-hour acoustics education outreach program developed for preschool and early primary school children is presented. In the program, children are involved in a discussion of the human auditory system and the dangers of noise exposure, engage in listening exercises using a keyboard synthesizer, construct a small musical instrument, and finally play the musical instrument with the rest of the class in a marching band.
The acoustics of the hammered dulcimer and similar instruments
Authors: Peterson David
Published: October 2013

The hammered dulcimer, an antecedent of the piano, apparently originated in the Middle East sometime around the 14th century. A typical instrument has 23 to 30 courses of strings, two to four strings per course, and is played with two wooden hammers. As in the yang qin and other Asian dulcimers, bridges separate some string courses into two notes. In American instruments the treble bridge creates a musical fifth, which facilitates the speedy playing of diatonic scales and also creates a strong harmonic structure to the tone. In response to player demand, modern builders have used improved or new materials (glues, woods, composites, plastic) and better design to create a lighter and less resonant instrument with a greater musical range. Dr. Peterson will demonstrate various playing styles.
On the factors for detecting mistuned conditions and guiding their corrections for the Koto tuning
Authors: Ando Tamaki
Published: October 2013

By observations at the Koto tuning practice, it is realized that the bridge is moved in the period of about 400 ms, which is too short to feel the sensation of beat. Then, two kinds of listening tests were planned. The test sounds composed of two Koto sounds which should be tuned in one octave interval were presented at the same time like a part of actual Koto tuning process. The lower tone was at 196.9 Hz, the pitch of the higher one was varied in the range of 20 cents. Their length from the beginning was varied from 50 to 500 ms. The first experiment is for the judgment of the right or wrong tuning (higher or lower). The second one is for the tone color impression using 13 pairs of adjectives. The results of these experiments show that reasonable pitch judgments can be done for the test sounds longer than 200 ms by well-experienced Koto players, and the test sounds are clearly distinguished from each other by their tone color difference, whereupon in the Koto tuning by expert players, the direction and degree of mistuning are found to be judged at the initial stage of Koto sounds by the tone color impression.
Acoustics of the haegeum, a Korean string instrument
Authors: Yoo Junehee , Rossing Thomas D.
Published: October 2013

The Korean haegeum, closely related to the Chinese erhu and Japanese kokyo, dates back to the Goryeo Dynasty. It is played with a horsehair bow that is inserted between two strings attached to a small barrel-shaped resonator. A bow made up of a bamboo stick with lengths of horsehair is held by the right hand of the performer. The two strings are generally tuned to A3■ and E4■ and the resonator is tuned to about 300 Hz. The resonator has a paulownia wood plate at one end on which the bridge rests. By means of holographic interferometry, we compare modes of vibration in resonators of bamboo, ailanthus, birch, and ash.
Preliminary work on the development of a lexicon for supersonic aircraft sound
Authors: Marshall Andrew , Davies Patricia , Sullivan Brenda , Pilon Anthony
Published: October 2013

A series of tests was conducted in three sonic boom simulators to test how expert subjects perceived the realism of the sound playback. Subjects heard sounds (recorded sonic booms) in two simulators and rated them on a realism scale. On completion of this realism test, subjects were asked to write down descriptions of the sounds and also of real booms (indoor and outdoor) that they had heard in the past. They then listened to 14 sounds and, after each sound, wrote down adjectives and phrases describing the sound characteristics. The 14 sounds were also analyzed and sound attribute metrics calculated for the main part of the boom as well as for the after-boom noise. The results of this analysis were compared to the words used to describe the sounds, and a preliminary set of words is proposed for inclusion in a lexicon for supersonic aircraft sound.
Modifications to the Gulfstream sonic boom simulator for the enhancement of low-boom simulations
Authors: Babcock Chris , Salamone Joe
Published: October 2013

A procedure is presented to enhance the simulation of measured low booms. Qualitative results show the SASSII, as originally designed, successfully reproduced the realism of full scale N waves. The simulator did not meet the realism level of the full-scale N waves when trying to reproduce the realism of lower amplitude sonic booms referred to as low booms. Data acquisition hardware was upgraded. Time alignment of each driver was performed with a different technique. Equalizer and amplifier programming was modified for each driver to provide a higher signal-to-noise ratio necessary to increase the realism of measured low booms in the simulator. A multipoint equalization was performed with a modified listening area. An iterative method rather than direct method was used to solve for the system of equations generated by the Weiner filtering scheme. The results are evaluated quantitatively by comparing the perceived loudness, A-weighted, and C-weighted sound-exposure levels of the full-fidelity waveform compared with the system output in the listening area.
Prediction and measurement of sonic booms generated by the launch of a Minuteman II missile
Authors: Pettyjohn Steven D.
Published: October 2013

The Air Force wanted to launch a Minute II missile full range. Predictions were 15.9 psf of over pressure at the sonic boom focus using similitude based on Saturn 5 data. Since this is at the threshold where single strength glass could break, a decision was made to predict over pressure using a NASA program. This program predicted a level of 16.1 psf over pressure, just 1.3% greater than the original estimate. Confirmation was made by measuring the sonic boom from the launch out of Vandenberg Air Force Base. Seven small boats equipped with sound-activated tape recorders were placed along the flight path with some boats placed at the predicted focus point based on the weather forecast provided by the Air Force. Based on work by A.D. Pierce, two distinct N-wave types were expected. One would represent the path from where the missile first reached sonic speeds and would propagate along a fairly shallow path with respect to the earth’s surface. The second wave type would arrive from a much higher elevation in the flight path and would propagate through many atmospheric layers. Weather forecasts were incorrect, but the results show the two shock wave types.
Optical imaging of neural activity to vocalized sounds in the guinea-pig auditory cortex
Authors: Horikawa Junsei , Hatta Takashi , Sugimoto Shunji , Hosokawa Yutaka , Kubota Michinori
Published: October 2013

Spatiotemporal neural activity in response to vocalized sounds (calls) was investigated in the auditory cortex of anesthetized guinea pigs using an optical imaging technique with a voltage-sensitive dye (RH795). Guinea-pig calls were recorded digitally and presented to the ear from a loudspeaker located contralaterally to the recording cortex. Pure tone (PT), click (CLK), and white noise (WN) stimuli were used for comparison. The response in the primary (AI) and dorsocaudal (DC) fields of the auditory cortex to a PT appeared at the stimulus onset and in the corresponding frequency band, followed by nonsimultaneous lateral inhibition in the adjacent frequency bands. The responses to CLK and WN stimuli appeared in a wide area of the fields corresponding to the wide frequency components of the stimuli. The response to calls changed spatially and temporally because the components’ frequencies changed over time. Strong responses occurred in the frequency bands corresponding to prominent instantaneous frequency components. These results suggest that activity to calls in AI and DC fields is formed by spatiotemporal excitatory and inhibitory interactions between the frequency bands responding to instantaneous frequency components in the calls. [Work supported in part by the 21st century COE program ‘‘Intelligent Human Sensing’’ from the MESSC, Japan.]
Extraction of sounds’ time-frequency features in the auditory cortex
Authors: Sugimoto Shunji , Suzuki Yuuta , Tanaka Hiroyuki , Kubota Michinori , Horikawa Junsei
Published: October 2013

Although ‘‘time-frequency feature extraction’’ is a fundamental cue that is used to recognize speech sounds, its physiological mechanisms remain largely unknown. This research is aimed at understanding what time-frequency features of sounds are extracted by auditory cortical neurons. We investigated spatiotemporal response patterns in the guinea-pig auditory cortex, using an optical recording method (MiCAM Ultima; Brain Vision) with a voltage-sensitive dye (RH795). Experiments were performed under anesthesia (ketamine, 100 mg/kg, and xylazine, 25 mg/kg). Pure tones (PTs), frequency-modulated (FM) sounds with various modulation rates, and their combinations were presented to the animals. Cortical activation was induced at the onset and offset of PTs along the isofrequency contours. The onset response was followed by strong inhibition. In contrast, FM sounds evoked an additional activation moving across the isofrequency contours in the cortex, with locations corresponding to the instantaneous frequency input of the FM sweep. Such a response became more evident when the FM sweep rate increased. Based on these results, we discuss physiological mechanisms by which sounds with a rapid frequency modulation lead to ‘‘time-frequency feature extraction’’ in cortical neurons. [Work supported in part by the 21st century COE program ‘‘Intelligent Human Sensing’’ from the MESSC, Japan.]
Perceptual organization in loudness enhancement and decrement
Authors: Fantini Deborah A. , Plack Christopher J.
Published: October 2013

Loudness enhancement is an increase in the loudness of a target tone that occurs when a more intense inducer tone either precedes or follows the target. Loudness decrement is a similar effect in the opposite direction. The present work investigates the role of perceptual organization in this paradigm by employing a capture tone presented simultaneously with the inducer. In a pair of experiments, the inducer, target, and comparison tone were always 1 kHz. The capture tone, when present, was either 2.0 or 0.5 kHz (an octave above or below the target). A 10-ms inducer tone immediately preceded a 10-ms target, with a 10-ms comparison tone presented 850 ms later. Listeners were instructed to ignore the inducer and to judge whether the target or comparison tone was louder. Equal-loudness matches were estimated using two randomly interleaved adaptive tracks, one converging on the just-louder threshold and the other on the just-quieter threshold. Results from both enhancement and decrement experiments indicate that the addition of a capture tone significantly reduces the magnitude of the effect, however it does not eliminate the effect completely. These findings indicate that perceptual organization does play a role in the effects of an inducer tone on loudness judgments.
Perceptual dimensions of impulsive-source active sonar echoes
Authors: Summers Jason E. , Brock Derek , McClimens Brian , Gaumond Charles F. , Baer Ralph N.
Published: October 2013

Recent findings [J. Pitton et al., J. Acoust. Soc. Am. 119, 3395(A) (2006)] have joined anecdotal evidence to suggest that human listeners are able to discriminate target from clutter in cases for which automatic classifiers fail. To uncover the dimensions of the perceptual space in which listeners perform classification, a multidimensional scaling (MDS) experiment was performed. Subjects rated the aural similarity between ordered pairs of stimuli drawn from a set of 100 operationally measured sonar signals, comprising 50 target echoes and 50 false-alarm clutter echoes. Experimental controls were employed to evaluate consistency in judgments within and between subjects. To ensure that dimensions were discovered rather than imposed [Allen and Scollie, J. Acoust. Soc. Am. 112, 211–218 (2002)], subjects were neither trained in classification nor made aware of the underlying two-class structure of the signal set. While training improves classification performance, prior work suggests that both expert and nave listeners use the same perceptual space [R. Mackie et al., ONR Tech. Rep. 2723-1, NR 197-060/4-18-79 (1981)]. Results of the MDS study are presented, including an evaluation of the number of perceptual dimensions and their interpretation in terms of perceptual and physical attributes of the signals. [Work supported by ONR.]
Perception and production of virtual pitch by absolute-pitch musicians
Authors: Hsieh I-Hui , Saberi Kourosh
Published: October 2013

The ability of absolute pitch (AP) and control (non-AP) musicians to identify and produce musical pitch from long-term memory was investigated in three experiments. In experiment 1, subjects identified the pitch of either a missing-fundamental complex or a highpass-filtered piano note. Unlike control subjects, AP subjects were highly accurate (\?85%) in identifying virtual pitch even when cues were restricted to the 4th and 5th harmonics. In a second experiment, subjects produced, within 3 s, the pitch of a randomly selected musical note without an external acoustic reference through either (1) adjusting a octave-range slider or (2) voicing/singing the target note. AP subjects, but not controls, were highly accurate (0.3 semitone) in the adjustment task. However, both AP and non-AP subjects were extremely accurate (i.e., SD=0.97, 0.90 semitone error, respectively) in voicing the required pitches as determined from FFTs of the recorded voiced notes. In experiment 3, subjects identified pitch of solfeggio syllables at mismatched note frequencies, created by altering the sampling rate of digitally recorded voiced labels. Identification accuracy by AP subjects declined to 65%, supporting a cognitive/linguistic interference model. Implications of these findings for models of absolute pitch encoding will be discussed. [Work supported by NSF.]
Pitch estimation of bone-conducted ultrasound
Authors: Ito Kazuhito , Nakagawa Seiji
Published: October 2013

Although ultrasound is perceptible through bone conduction, its perception mechanism has been clarified only slightly. The subjective pitch of bone-conducted ultrasound (BCU) sounds like a tone or harmonic sound of ten-odd kilohertz, independent of its own frequency. It has been difficult to determine the frequency of the pitch precisely because the pitch varies among listeners and with the position and strength of BCU stimulation, moreover; BCU hearing is not masked well by air-conducted (AC) band-pass noise. In this study, the BCU pitch-perception mechanism was investigated using beats with AC tones. The AC tones of 10–17 kHz, for which the presence of the pitch of BCU had been expected, were presented sequentially together with BCU (30 kHz) stimulation. Listeners were asked whether or not they were able to hear beats. For comparison, bone-conducted (BC) harmonic sounds of audible frequency components (e.g., 11–16 kHz, 1-kHz step) were also investigated. Results showed that no beat was heard between the AC tones and the BCU, whereas beats between the AC tones and the BC harmonic sounds were heard, suggesting the possibility that the pitch-perception mechanism of BCU is different from those of AC and BC sounds in this audible frequency area.
Dynamic center of gravity effects: Matching virtual frequency glides
Authors: Hoglund Evelyn M. , Feth Lawrence L. , Krishnamurthy Ashok K.
Published: October 2013

Lublinskaja (1996) demonstrated that changing the amplitudes of two-resonance Russian vowels over time leads listeners to hear a glidelike transition that follows the dynamic center of gravity (COG). Anantharaman (1998) investigated COG transitions for sinusoidal signals by asking subjects to match frequency-modulated (FM) to virtual frequency (VF) glides. The amplitudes of two tones were simultaneously modulated to produce a percept of a glide with rising pitch, similar to that of an FM sweep, although the frequencies remained fixed. However, listeners might perform Anantharaman’s task by simply attending to the location of one of the anchor tones without perceiving the virtual glide, as the frequencies of the two component tones were changed to alter the frequency span of the VF glide. This study modified that work by fixing the anchor frequencies, but confirmed the potential for procedural artifacts. Two additional experiments eliminated FM signals altogether and asked listeners to match VF glides to VF glides. Even with anchor frequency roving, subjects were able to match the VF glide trajectories for frequency separations up to 6 to 8 ERB. Results were compared with predictions from the perceptual spectral centroid model. [Research supported by a grant from NIH/NIDCD R01-DC006879.]
Effect of number of masking talkers on masking of Chinese speech
Authors: Wu Xihong , Chen Jing , Yang Zhigang , Li Liang
Published: October 2013

In this study, speech targets were nonsense sentences spoken by a Chinese female, and speech maskers were nonsense sentences spoken by other one, two, three, or four Chinese females. All stimuli were presented by two spatially separated loudspeakers. Using the precedence effect, manipulation of the delay between the two loudspeakers for the masker determined whether the target and masker were perceived as coming from the same or different locations. The results show that the one-talker masker produced the lowest masking effect on Chinese speech. When the number of masking talkers increased progressively to 2, 3, and 4, even though informational masking progressively decreased, energetic masking progressively increased, leading to an increased total masking effect on targets. A new form of calculation of the speech intelligibility index confirmed an increase of energetic masking as the masking-talker number increased, even when the long-term average signal-to-noise ratio was unchanged. Some differences between Chinese speech masking and English speech masking were revealed by this study. [Work supported by China NSF and Canadian IHR.]
Sensitivity to increments analyzed separately for each level in a roving paradigm
Authors: Bonnel Anne-Marie , Hafter Ervin
Published: October 2013

Studies of level discrimination using a dual-task paradigm have shown no cost of shared attention when levels were roved, so that comparisons between targets and standards were in sensory-trace memory, but clear evidence of a cost when levels were fixed, and comparisons seemed based on context-coded memory. Interest in the effects of these two types of memory led here to an auditory single-task in which a trial consisted of a standard tone set to level (I), followed by a target that was (I) alone or (I+&♯916;I). Durations were 50 or 200 ms; standards ranged from 50 to 70 dB SPL. In line with the view that the near miss to Weber’s Law is negligible over this range, fixed standards provided constant thresholds (log&♯916;I/I). As typical, overall performance was reduced by roving, but a surprising result was that the magnitude of this loss depended on (I). Thus, roving had the least effect with the highest value of (I); then thresholds rose steeply as (I) was reduced. Independent of this slope, a wider range of roving produced a greater overall loss. This is discussed in terms of an additive noise, possibly connected to the use of trace memory.
Reproducible maskers reveal similar mechanisms predicting multiple-burst-same and multiple-burst-different informational masking conditions
Authors: Gilkey Robert H. , Mason Christine R. , Kidd Gerald
Published: October 2013

Gilkey, Mason, and Kidd [J. Acoust. Soc. Am. 109, 2468 (2001)] found that although informational masking has typically been thought to depend more strongly on the variability in the ensemble of masking stimuli presented across trials, trial-by-trial performance was strongly related to the specific masker waveform presented on each trial. Moreover, hit and false-alarm rates to individual masker stimuli under multiple-burst-same (MBS) conditions were well predicted by the patterns of energy in those stimuli. Hit and false-alarm rates under the multiple-burst-different (MBD) condition were more difficult to predict. This paper reports on further efforts to model those data. The results indicate that performance under both MBS and MBD conditions can be predicted using a linear combination of envelope statistics computed from seven narrow frequency bands surrounding the 1000-Hz signal frequency. MBS responses are related to the average height of the envelope in these bands and MBD responses are related to the standard deviations of the envelopes. [Work supported by NIH/NIDCD.]
The development of models for the prediction of noise-induced hearing loss
Authors: Qiu Wei , Ye Jun , Hamernik Roger P.
Published: October 2013

Three statistical learning models were developed to predict noise-induced hearing loss (NIHL) from an archive of animal noise exposure data, which contains 936 chinchillas exposed to various noise environments. The following models were constructed: (i) A support vector machine model with a nonlinear radial basis function kernel. (ii) A multilayer perceptron network model and (iii) a radial basis function network model. In addition to frequency-specific energy metrics, noise exposure parameters and biological metrics such as kurtosis, noise type, and pre/postexposure hearing thresholds were used as inputs to the model. There were several indices of auditory trauma at specific audiometric test frequencies that were to be predicted by the models: e.g., noise-induced permanent threshold shift, percent outer hair cell loss, and percent inner hair cell loss. The average prediction accuracy for the three models was better than 80%. These results demonstrate the feasibility of developing such models for the prediction of NIHL in humans. [Research supported by NIOSH.]
The application of the equal energy hypothesis (EEH) to interrupted, intermittent and time-varying Gaussian noise exposures
Authors: Qiu Wei , Hamernik Roger P. , Davis Robert I.
Published: October 2013

Interrupted, intermittent, time-varying (IITV) noise exposures may reduce the susceptibility of the cochlea to hearing loss through toughening or conditioning effects. Six groups of chinchillas were exposed to a broadband Gaussian IITV noise over the course of 19 days at an Leq=101 or 106 dB(A) SPL. All exposures at a given Leq had the same total energy. Each daily exposure consisted of two 4.25-h periods with an hour break in between. Each 4.25-h exposure was interrupted for 15 min and each 5-day sequence was separated by a 2-day break. Daily IITV exposures at 101 dB varied between 90 and 108 dB(A), while those at 106 dB(A) varied between 80 and 115 dB(A). For the IITV exposures three different variations in the SPL temporal profile were used. Five-day continuous, equal energy exposures at 100 or 106 dB(A) SPL served as control conditions. The IITV exposures produced up to 40 dB toughening that did not have any effect on thresholds or sensory cell losses. There were some differences in the permanent threshold shift and cell loss across equal energy exposures but the differences were small. The EEH may be valid for Gaussian IITV exposures. [Work supported by NIOSH.]
Predictions of Mandarin Chinese tone identification in cochlear implants using particle filters
Authors: Morton Kenneth D. , Collins Leslie M.
Published: October 2013

The spectral information provided in current cochlear implants is inadequate for reliable speech perception in tonal languages. Speech comprehension in a tonal language, such as Mandarin Chinese, requires recognition of lexical tones. New strategies for sound processing may allow the transmission of more spectral information and may therefore improve Mandarin Chinese tone recognition. Four cochlear implant speech processing strategies were examined in this study. Each provides a different amount of spectral information. Automated pattern recognition of Mandarin Chinese tones processed using cochlear implant acoustic models can be used as a means of testing the abilities of each of the algorithms to transmit the necessary spectral information for accurate tone perception and may be used to focus future Mandarin Chinese tone recognition studies in cochlear implant subjects on the most promising speech processing strategies. Classification based on spectral features derived from particle filtering is compared to classification derived from other features in an effort to determine the necessary spectral information for accurate tone classification in both quiet and noisy conditions. Automated classification results will be compared to the results of a listening experiment using normal-hearing subjects and acoustic models.
Simulating the effect binaural (electric and acoustic) hearing on Mandarin speech recognition under background noise for patients with cochlear implant (CI)
Authors: Wu Chao-Min , Cheng Wei Jen
Published: October 2013

This study evaluated the effects of binaurally combined electric and acoustic hearing on Mandarin speech recognition under simulated background noise for normal-hearing (NH) listeners and CI recipients of the Nucleus-24 device with contralateral hearing aid (HA). Chinese word and tone recognition were measured in seven NH subjects using simulated four-channel continuous interleaved sampler (CIS) type speech processing strategy under three different conditions, namely, (1) only simulated (CI) signals with modulated Gaussian white noise for monaural stimulation, (2) simulated (CI) signals with modulated Gaussian white noise and simulated HA signals (low-pass speech signals with cutoff frequency of 500 Hz) for monaural stimulation, and (3) simulated (CI) signals with modulated Gaussian white noise to one ear and simulated hearing aid (HA) signals to the other ear for dichotic stimulation. For comparison purposes, Chinese word and tone recognition were also measured in three CI users using advanced combination encoding (ACE) strategy. Preliminary results showed that the Chinese word and tone recognition rates of the NH listeners and CI recipients are statistically significantly improved (word and tone recognition rates were improved from 3.85% to 60.86% and 40.14% to 97.43% for NH listeners and 20% to 37.5% and 50% to 90% for CI recipients).
Effects of material orientation on the radiation efficiency of baffled plates
Authors: McDaniel J. Gregory
Published: October 2013

The orientation of an anisotropic material may have profound effects on acoustic radiation from the structure. The present work explores these effects for the case of a thin anisotropic plate in an infinite rigid baffle. An understanding of the acoustic radiation, in terms of the radiation efficiency, is begun by considering two effects. The first is that of wave steering, in which the direction of structural wave propagation is changed by the material orientation. The second is that of wave mixing, in which the the relative mixture of propagating and evanescent waves is changed by the material orientation. The effect on radiation follows from the fact that radiation from propagating and evanescent waves is known to be dramatically different. The relative importance of frequency and excitation is also explored in the context of these two effects. These results are expected to lead to improved designs of composite structures at no additional cost—simply by changing the orientation of the material. [Work supported by ONR.]
A method to measure the equivalent acoustic impedance of a scatterer
Authors: Lee Seung-ha
Published: October 2013

The procedures of simplifying scatterers’ geometry and finding its equivalent acoustic impedance are proposed by using scattering holography and multiple multipole expansions. The scattered sound field depends on the incident field, the geometry, and the physical property of the scatterer, which can be measured by using tools such as a set of microphones and a 3-D scanner. Once the sound field over a surface is measured, the whole sound field of 3-D space can be reconstructed by acoustic holography. However, predicting near-field sound by holography is inefficient in practice, because huge numbers of measurement points are required to describe the complex sound field in the vicinity of a scatterer. With this regard, multiple multipole expansions are employed to reduce the number and the size of elements of a scatterer necessary to express the measured scattered field. Therefore it is equivalent to simplifying the geometry of a scatterer, and enables us to predict the sound pressure and velocity, as well as acoustic impedance, on the scatterers’ surface. Using the proposed method, it is demonstrated that the equivalent acoustic impedance can be obtained. [Work supported by the BK21 project initiated by the Ministry of Education and Human Resources Development of Korea.]
Using speech recognition for just-in-time language learning
Authors: Eskenazi Maxine , Raux Antoine , Harris Elizabeth
Published: October 2013

While many language learning systems rely on the student to be a dedicated learner, the opportunity to teach language is present outside the classic teaching situation, in all everyday oral and text-related activities. Teaching language in real situations, where the new knowledge is needed and used immediately, has great potential for robust learning: items are retained over a long period of time, make learning other items easier, and are generalized to other situations. Giving immediate and effective error detection and corrective feedback is a technical challenge for language modeling, spoken dialogue structure, and targeted speech synthesis. We will discuss just-in-time language learning and then present one type of just-in-time learning, lexical entrainment, where the automatic system detects an oral error and then respeaks the utterance that contained the error in corrected form, emphasizing the corrected portion. To test the effectiveness of this approach, the Lets Go spoken dialogue system that furnishes bus information to Pittsburghers was modified to predict errors from a variety of non-native speakers of English. A study of the effectiveness of lexical entrainment for a group of non-native users will be described. [This work is sponsored by NSF Grants 0208835 and IIS0096139.]
The effects of layering on reflection coefficient and transmission measurements from a sand/water interface at the Sediment Acoustics Experiment 2004 (SAX04)
Authors: Isakson Marcia
Published: October 2013

During the Sediment Acoustics Experiment 2004 (SAX04), transmission measurements from 4.5 to 50 kHz were taken on an eight-transducer array buried at an angle of 15 deg using a source mounted on a remotely operated vehicle (ROV). Simultaneously, the reflection coefficient was measured using a three-receiver vertical line array (VLA). Reflection coefficient measurements at angles from 10 to 70 deg were obtained. Environmental characterization of the area has revealed layering effects such as a surficial mud layer, mud inclusions, and depth-dependent sediment properties such as porosity. The consequence of this layering on the variability of the amplitude of reflection coefficient measurements and the time of arrival of transmission measurements will be investigated. [Work supported by ONR, Ocean Acoustics.]
The design of a boundary element package for treating acoustic scattering from buried objects
Authors: Burgschweiger Ralf , Ochmann Martin , Nolte Bodo
Published: October 2013

The target strength of objects placed in water and partially buried in the sediment are calculated by means of a boundary element solver. For this reason, a boundary element code with suitable pre- and postprocessor is developed. With the help of the preprocessor, the scattering objects within the transition range between fluid and sediment can be modeled. The preprocessor can manage large and complex meshes (more than 100000 elements) and is able to import NASTRAN and ANSYS mesh-files. It automatically generates closed geometric meshes. These meshes are used as database for the BEM calculations. For reducing computing time, the boundary element solver runs on a high number of personal computers in parallel equipped with Windows- or Linux-operating systems. These calculator hosts will receive their task from the preprocessor using TCP/IP-based interprocess communication. The parallel calculations can be performed as a service in the background and remotely administrated by the postprocessor. The postprocessor polls the results from the calculator hosts, delivers them to the appropriate projects, and provides visualization and analysis of the results. The efficiency of such a parallel processing boundary element package will be demonstrated for the acoustic scattering at simple test objects consisting of a high number of surface elements.
Sound-absorbing material made of recycled polyester nonwovens using scrapped pieces
Authors: Fujimoto Kazutoshi , Anai Ken , Nakano Tatsurari , Koga Shin-ichi
Published: October 2013

The authors developed polyester nonwovens (PW) that have nearly equivalent sound absorption to glass wool with similar thickness and density. Unfortunately, scraps amounting to 20% of crude polyester are generated during PW manufacturing and cutting. They must be discarded as waste materials. Therefore, the authors contrived an original recycling technique to use such scrap pieces. Sound absorption characteristics of recycled materials manufactured using this method (RPW) are inferred to differ from those of PW because of their different fiber compositions. In this study, sound absorption of RPW is measured and the following points are examined experimentally: the relationship between manufacturing processes and sound absorption of RPW; sound absorption of RPW when two kinds of scrap pieces are mixed; and effects of mixing crude materials on RPW sound absorption. Results indicate that RPW has sufficient sound absorption for practical use. Comprising scrapped pieces that have been discarded as waste, RPW addresses the social importance of good resources usage and waste reduction; it also offers advantages of lower cost than PW. This RPW material is anticipated for use in various fields as a sound-absorbing material.
Acoustics of ancient Greek and Roman theaters in use today
Authors: Gade Anders Christian , Angelakis Konstantinos
Published: October 2013

In the Mediteranan area a large number of open, ancient Greek and Roman theatres are still today facing a busy schedule of performances including both classical and contemporary works of dance, drama, concerts, and opera. During the EU funded ‘‘Erato’’ project and a subsequent master thesis project, extensive measurement data have been collected from three well-preserved theatres, which represent three different stages of enclosing the audience in an open-air environment: (1) the Epidaurus Theatre in Greece without skenae wall or columnade behind the cavea; (2) the Jerash South theatre in Jordan with skenae wall but no columnade; and (3) the Aspendos Theatre in Turkey having both a full skenae building and a columnade around the cavea. In the paper the acoustic characteristics of these theatres will be compared and discussed in the light of acoustic performance requirements for modern use.
Training musicians and nonmusicians to discriminate Mandarin tones
Authors: Gottfried Terry L. , Ouyang Grace Y.-H.
Published: October 2013

Musicians and nonmusicians were compared in their ability to learn Mandarin tone contrasts. Participants were pretested to assess their accuracy in tone discrimination. Some were then given six sessions of articulatory and acoustic training over 3 weeks; others were given no training. At the end of 3 weeks, participants were again tested on their discrimination accuracy. Listeners judged whether the tones (tone 1, high level; tone 2, mid rising; tone 3, low dipping; tone 4, high falling) of two different Mandarin syllables were the same or different. In some trials, listeners discriminated tones in words spoken by two speakers; in other trials, they discriminated tones in words spoken by one speaker only. The pretest revealed that musicians are significantly more accurate in discriminating Mandarin tones than nonmusicians. Musicians and nonmusicians who received the training regimen performed more accurately than untrained listeners on the posttest discrimination. Musicians showed significantly less improvement than nonmusicians with training, probably due to ceiling effects (their posttest accuracy was over 95%). Two-speaker discrimination trials were significantly more difficult for all listeners, but especially for nonmusicians. Discrimination of tones 2 and 3 was most difficult for all listeners, but showed considerable improvement after training.
Augmented-reality virtual-diffusion system: A tool to evaluate listener comfort
Authors: Novo Pedro
Published: October 2013

The augmented-reality virtual-diffusion system presented here aims to evaluate the comfort of a subject listening to a nearby speaker located in a room filled with a diffuse crowd. The main parameter to be studied is sound field diffusion and its relation to comfort. To this purpose a virtual diffusion system, based on electro acoustic transducers mounted on the walls, is employed to actively change the properties of the diffuse sound field. The augmented reality factor is introduced through the interaction of the virtual diffusion system with the acoustics of the room. The present paper presents a brief description of the approach chosen to implement the augmented-reality virtual-diffusion system. Diffusion measurements obtained with both virtual and real diffusers are compared. Results regarding auditory events location evoked by different sound fields and predictions from a cross-correlation-based binaural model employed to model these results are discussed. Initial results relative to comfort evoked by the different sound fields as well as a possible relation between auditory events location and listener comfort are discussed.
Linearized and nonlinear dynamics of bowed bars
Authors: Inacio Octavio , Antunes Jose
Published: October 2013

Friction-excited instruments have been for many decades an inexhaustible source of physical delight. In the last decades, spectacular improvements in computational power and in numerical methods enabled simulations of the self-excited nonlinear regimes with considerable realism and detail. The authors of the present paper have achieved many such nonlinear simulations, using a powerful modal approach, and decided to investigate here in detail the characteristics of the linearized and nonlinear regimes of bowed bars. After stating the theoretical modeling approach for the nonlinear problem, we derive a corresponding linearized model, from which the complex eigenvalues and eigenvectors are computed as a function of the bowing parameters (friction parameters, normal force, and tangential velocity, accounting for the bowing location). We thus obtain plots of the modal frequencies, damping values, and complex mode shapes, as a function of the bowing parameters, as well as stability charts for each one of the system modes. When compared with the nonlinear motion regimes, these results offer interesting information concerning the stability behavior of the system, and further insight when addressing the postinstability nonlinear limit-cycle responses. Several differently tuned bars are addressed in order to assert the configurations leading to optimal playability.
Acoustical and optical characterization of air entrapment in piezo-driven inkjet printheads
Authors: Lohse Detlef , de Jong Jos , Jeurissen Roger , Versluis Michel , Reinten Hans , van den Berg Marc , Wijshoff Herman
Published: October 2013

Stability of inkjet printers is a major requirement for high-quality printing. However, in piezo-driven inkjet printheads air entrapment can lead to malfunctioning of the jet formation. A voltage pulse applied to a piezoelectric element causes an ink-filled channel to deform, thereby creating a pressure waveform in the ink. Fluid acoustics are involved to guide the waveform energy towards the nozzle and to create pressure and velocity profiles needed for the droplet jetting process. Droplets are jetted every 50 μs, and the typical nozzle size is 30 μm. The piezo actuator is employed to actively monitor the channel acoustics and to identify distortions at an early stage. Modifications of the response of the piezo actuator indicate entrapped air bubbles and these allow us to investigate them. When the signal is employed as a trigger for high-speed imaging, the consequences of the entrained bubbles on the droplet formation can be visualized. [This study has been financed by the Fundamenteel Onderzoek der Materie (FOM) of The Netherlands under Grant. No. 02MFS39 and by Océ Technologies B.V.]
Model for the interaction between a bubble and an elastic particle
Authors: Hay Todd A. , Hamilton Mark F.
Published: October 2013

At the Providence meeting, a model describing the interaction of a spherical bubble with a rigid spherical particle was presented [Hay and Hamilton, J. Acoust. Soc. Am. 119, 3408 (2006)]. Here, elasticity of the particle is considered. The model accounts for pulsation and translation and is accurate to fifth order in terms of the ratio of characteristic radius to separation distance. The dynamical equations are derived using the Lagrangian formalism of Ilinskii et al. [Proc. 17th ISNA, edited by Atchley et al. (AIP, New York, 2006), pp. 303–310]. Bubbles and elastic solid particles are considered with radii on the order of microns and driven at megahertz frequencies. The radial particle motion is quasistatic under these conditions. For moderate bubble pulsations at which the liquid may be considered incompressible, translational motion of the bubble and particle is insensitive to whether the particle is elastic or rigid. Consideration is also given to truncation of the model at fifth order. Derivation of the model equations to arbitrary order was facilitated by the development of a computer algebra program. The importance of including higher-order terms for small separation distances is illustrated. [T.A.H. was supported by an NSF Graduate Research Fellowship.]
Deformation of a single bubble in organic solutions by ultrasound
Authors: Itami Hiroshi , Mukasa Shinobu , Nomura shinfuku , Toyota Hiromichi , Takahashi Yoshiyuki
Published: October 2013

Behavior of a single bubble under an ultrasound resonant state in a hydrocarbon liquid such as n-dodecane or benzene was observed using a stroboscope and a charge-coupled device (CCD) camera. Although sonoluminescence was not confirmed because of bubble stability limitations, bubble deformation was observed at a situation of stability limitation. Deformation occurred when the bubble contracted to its minimum size. Numerical analyses of deformation growth by Rayleigh-Taylor instability of an oscillated bubble were carried out at the surface. The distortion amplitude of all degrees continued oscillating as the bubble expanded or contracted, and the oscillation frequency increased with the degree. The distortion amplitudes are amplified through the afterbounce by the resonance effect if the oscillation frequency of the distortion amplitude of some degree is approximately equal to the frequency of the afterbounce. The distortion amplitude of all degrees, except for amplified degrees, was dampened by the viscosity effect, and if the distortion amplitudes of all degrees were dampened, the bubble was considered to form a sphere and become stable. A phase diagram of stability of an oscillated bubble showed a function of an ambient bubble radius and the amplitude of forcing pressure.
Observe multibubble cavitations in the ultrasonic cleaning tank
Authors: Noritoshi Nakagawa , Chaoqun Wu , Yasuhisa Sekiguchi
Published: October 2013

A cylindrical ultrasonic cleaning tank radiated by a PZT with a large horn operated at 27.3 kHz is employed to investigate the manifestations of cavitation in the present research. The characteristics of this cleaning system are analyzed using experimental methods. In this cleaning tank, the nonuniformity of vibration velocity on the radiation surface induces the Eckart streaming, which can eliminate the effect of a standing wave on cleaning efficiency. Fresh tap water and degassed water are employed as test liquids in this research. In tap water, conical streaming is observed as the input voltage of the transducer is increased over 100 V. The structure of conical streaming is anatomized. Its shape varies with the change of input voltage. In degassed water, ultrasonic fireworks are observed and special attention is paid to their subsequences, snowflake bubble clouds and water jet.
Characterization of in-liquid plasma in a continuous liquid flow
Authors: Toyota Hiromichi , Nomura Shinfuku , Mukasa Shinobu , Yamashita Hiroshi , Kawashima Ayato , Maehara Tsunehiro
Published: October 2013

In-liquid plasma is a useful invention because its chemical reaction rate is several thousand times higher than those of conventional plasma techniques. However, in-liquid plasma is not so familiar now because its fundamental characteristics remain unclear. We investigated characteristics of in-liquid plasma in a continuous liquid flow to facilitate its application as a chemical decomposition or synthesis device. N-dodecane is supplied by the pump and a stable liquid flow is set in the rectangular vessel. Because the flow velocity is insufficient, a nozzle is set 2 mm distant from the microwave electrode tip. The average flow velocity of n-dodecane at the nozzle top is 0–19 m/s and the Reynolds number is as high as 1.2×104. A 2.45-GHz microwave is introduced by a monopole antenna electrode inserted into a rectangular cavity resonator. In-liquid plasma is generated and observed in the flowing cavitation bubbles generated from the ultrasonic horn tip. The vessel’s inner pressure is adjusted to 65–450 hPa. The temperature in the plasma reached 3600±300 K; it was almost independent of the flow velocity because the physical properties of the plasma are influenced only slightly by the acoustic cavitation stream.
Microbubble shape oscillations excited through an ultrasound-driven parametric instability
Authors: Versluis Michel , Palanchon Peggy , Goertz Dave , de Jong Nico , Heitman Ivo , van der Meer Sander , Dollet Benjamin , Lohse Detlef
Published: October 2013

An ultrasonically driven air bubble can become shape-unstable through a parametric instability. Here, we report time-resolved optical observations of shape oscillations (mode n=2 to 6) of micron-sized single air bubbles for a range of acoustic pressures. The observed mode number n was found to be linearly related to the resting radius of the bubble. Above the critical driving pressure threshold for shape oscillations, which as expected is minimum at the resonance of the volumetric radial mode, the observed mode number n is independent of the forcing pressure amplitude. The microbubble shape oscillations were also analyzed numerically by introducing a small, nonspherical linear perturbation into a Rayleigh-Plesset-type equation model which includes a physical thermal damping mechanism describing heat and mass transport in the thin boundary layer at the bubble-to-water interface. Indeed, a parametric instability is responsible for the shape oscillations, and the Rayleigh-Plesset-type equation captures the experimental observations in great detail.