bluuebunny/crossref_metadata_2025 huggingface dataset:
Measurement of density and size distribution of oscillating cavitation bubbles using optical spectrometer
Authors: Kuroyama Takanobu , Ebihara Tadashi , Mizutani Koichi , Ohbuchi Takeshi
Published: April 2012

Measuring of properties of acoustic cavitation bubbles, such as size distribution and density distribution, is important to estimate the physical and chemical effects of the cavitation bubbles. In this paper, the optical spectrometer is applied to measure the bubble density in the cavitation field. In previous study, it has been proposed that a size distribution measurement method of the acoustic cavitation bubbles using the optical spectrometer by the authors. The size distribution measurement of the oscillating bubbles was successfully achieved by measuring the far-field (Fraunhofer) diffraction pattern of the bubbles, which was obtained by introducing the laser light to the cavitation bubbles. In addition to the previous study that focused on the diffracted light pattern, the bubble density is measured from the diffracted light intensity in this paper. The obtained results suggest that the proposed method can measure the bubble densities successfully.
Mapping the human cortex associated with auditory processing in space, time and frequency using different neuroimaging techniques
Authors: Lee Adrian KC
Published: April 2012

Functional magnetic resonance imaging (fMRI), Magneto- and Electro-encephalography (M-EEG) are neuroimaging techniques that have been used extensively to study human auditory perception and cognition. Due to the different spatial and temporal resolutions associated with these methods, each technique offers a different unique window into how our cortex participates in auditory tasks. In this talk, a summary of how each presentation in this session leverages the strengths of these neuroimaging techniques to map how our cortex dynamically responds to different sound features will be presented. Other methodological advances that are particularly relevant to experiments in auditory perception and cognition will also be discussed. Funded by USA-NIH R00DC010196.
Using functional magnetic resonance imaging to explore the representation of binaural cues in human auditory cortex
Authors: Stecker G Christopher , McLaughlin Susan A
Published: April 2012

Functional magnetic resonance imaging (fMRI) was used to examine representations of interaural differences of level (ILD) and time (ITD) in human auditory cortex (AC). In one experiment, ILD of amplitude-modulated sounds varied parametrically across 12-s blocks, with a single image acquired at the end of each block (i.e., using a “sparse” imaging protocol). In another experiment, ILD or ITD varied parametrically across brief (1-s) presentations, and responses measured from continuosly-acquired images using an “event-related” paradigm. Whole-head echo-planar imaging (~3x3x3 mm resolution) was conducted at 3T (Philips Achieva), with sounds presented via insert earphones (Sensimetrics). Blood-oxygenation-level-dependent (BOLD) signals were analyzed on each individual's cortical surface using FSL, Freesurfer, and MATLAB. In this presentation, results will be discussed in terms of (1) the tuning of BOLD responses to ILD and ITD; (2) the relationship between tuning to ILD and tuning to monaural intensity; (3) ILD-related information as assessed using multi-voxel pattern analysis; (4) adaptation of the BOLD response as a function of trial-to-trial variation in binaural cues; and (5) whether the BOLD responses reflect physical versus perceptual (e.g., perceived location or loudness) aspects of auditory experience. [Supported by NSF DBI-0107567, NIH R03-DC009482-02S1, R01-DC011548, T32-DC005361]
Decoding feature information in human auditory cortex—A comparison of auditory perception, short-term memory and imagery
Authors: Linke Annika Carola , Cusack Rhodri
Published: April 2012

The flexible nature of auditory cortex, the complexity of real-world sounds, and limitations of the methods for neural measurement in humans have made it difficult to investigate auditory feature information processing in the human brain. Which precise features are encoded in auditory cortex and the roles they play in different cognitive tasks remained unclear. New methods for functional magnetic resonance (fMRI) provide solutions to these limitations. New acquisition sequences make less noise, improving the suitability of fMRI for auditory research. Real-time adaptive fMRI and multivariate pattern analysis methods are robust to individual differences in anatomy and exploit information in distributed neural networks. They allow assessment of which acoustic and abstracted features of simple and natural sounds are represented in human auditory regions during perception, and cognitive tasks such as change detection and imagery. The results indicate that auditory cortex is recruited for processes beyond analyzing simple feature information, playing an important role in maintaining sounds in short-term memory and encoding abstracted information during imagery. This research was supported by the Medical Research Council (UK) and The Brain and Mind Institute, University of Western Ontario.
Hemispheric specialization in auditory processing of Chinese lexical tones: a study using whole-head recordings of EEG
Authors: Wang Xiao-Dong , Gu Feng , Chen Lin
Published: April 2012

It has long been established that the left hemisphere is specialized for speech whereas the right for music. However, it remains elusive whether the labor division between the two hemispheres is determined by function or acoustic property of stimuli. The confusion in the literature raises a possibility that the two factors are involved at different levels of auditory perception, respectively. In the present study, we demonstrate the dependence of hemisphere specialization on acoustic properties of stimulus in early auditory processing. We frequently presented to Mandarin Chinese speakers a meaningful consonant-vowel syllable and infrequently varied either its lexical tone or initial consonant to result in changes in word meaning. The lexical tone contrasts evoked a stronger pre-attentive electric response, as revealed by whole-head recordings of the mismatch negativity, in the right hemisphere than in the left but the consonant contrasts produced an opposite pattern. This hemisphere dominance was acoustically dependent since lexical tones and consonants in Chinese have an equal function in defining word meaning but have distinct spectral and temporal features. Our finding suggests that dominant involvement of functional cues in hemisphere specialization is only possible at a higher level of auditory processing.
Benefit and limitation of combining MEG and fMRI to study correlates of perception in the auditory cortex
Authors: Gutschalk Alexander , Steinmann Iris , Wiegand Katrin , Dykstra Andrew
Published: April 2012

MEG is a strong tool for cognitive hearing research, because it allows for studying the brain's function in silence and with high temporal precision. However, MEG's ability to clearly separate neighboring sources, e.g. primary and secondary auditory cortex, is limited. While fMRI is more precise with respect to the latter requirement, it lacks the previous two advantages. Here we will demonstrate two examples of combined MEG and fMRI: The first example is perceptual awareness under informational masking. MEG revealed a distinct negative response that is evoked when listeners indicated to be aware of targets in presence of an informational masker, but not when targets were successfully masked. Earlier activity from primary auditory cortex was evoked by all targets and was independent of perceptual awareness. Nevertheless, fMRI shows that activity related to awareness is, at least in part, also generated in the primary auditory cortex. The second example is periodicity pitch; while MEG has consistently revealed responses related to periodicity and supposedly pitch in lateral Heschl's gyrus, fMRI results have been inconsistent. In a direct comparison, we could show that fMRI activity is not predominantly related to the evoked pitch response in MEG, demonstrating limitations for the combination of the techniques.
Hijacking gamma oscillations during auditory attention
Authors: Shinn-Cunningham Barbara , Bharadwaj Hari , Lee Adrian KC
Published: April 2012

Neuroelectric imaging methods (electroencephalography and magnetoencephalography) can reveal cortical activity phase locked to amplitude modulation in sensory inputs for frequencies up to about 100 Hz. The neural response at the input modulation frequency is known as the visual or auditory steady-state responses (VSSR or ASSR, depending on input modality). In vision, VSSR strength is modulated by attention: energy in the frequency modulating an attended object is enhanced, while the VSSR to a distracting object is suppressed. However, in the literature, attention causes less consistent effects on the auditory steady-state response. We combined M/EEG to study how the ASSR is modulated when listeners focus spatial attention on one of two speech streams. We find that attention enhances the ASSR power at the frequency of an attended stream in auditory cortex contralateral to the attended direction. The attended-stream modulation frequency also drives phase-locked responses in left, but not right precentral sulcus (which is associated with control eye gaze and spatial attention). This asymmetric activation of the attentional network helps explain seemingly contradictory results of past auditory studies, most of which used dichotic rather than binaural simuli and analyzed results in sensor space or assumed particular dipole solutions rather than doing whole-brain analysis.
Behavioral and physiological measure for pitch matching between electrical and acoustical stimulation in cochlear implant patients
Authors: Tan Chin-Tuan , Guo Benjamin , Martin Brett , Svirsky Mario
Published: April 2012

This study examines behavioral and physiological measures of pitch matching in cochlear implant (CI) users who have residual hearing in the contralateral ear. Subjects adjusted the frequency of an acoustic tone to match the pitch percept elicited by electrical stimulation in the other ear, when stimulation was alternating across two ears. In general, the selected acoustic frequencies did not line up perfectly with the center frequencies of the analysis bands corresponding to each stimulation electrode. Similar alternating electro-acoustic stimuli were used to record Auditory Evoked Potentials on 8 NH subjects and 3 CI patients. NH subjects were presented with a fixed tone in one ear, while tones in the other ear varied within a few octaves from the fixed tone. CI patients were stimulated with six different audible tones including their pitch-matched tones, while receiving electrical stimulation in the electrode. N1 latency for NH subjects was minimized when the same frequency was presented to both ears. Similarly, N1 latency for CI patients who are able to pitch match was minimized when the tone was at the pitch matched frequency of the stimulated electrode. These results suggest that N1 latency can be a possible objective measure of pitch matching. (Work supported by NIH/NIDCD 1K25DC010834-01;PI:Tan, PSC-CUNY;PI:Martin, and NIH/NIDCD R01-DC03937;PI:Svirsky.)
Measurement of the noise radiation of the panels subjected to turbulent boundary layer pressures
Authors: Chang Daoqing , Chen Xiang , Qian Zhongchang , Liu Bilong
Published: April 2012

The noise radiation of the panels with different treatments under a turbulent boundary layer (TBL) excitation is tested in an anechoic wind tunnel. The averaged dimensionless spectrum for the response and the radiated sound power of panels with different size, stiffening and damping treatments are collected at the condition of various flow speeds. Numerical analysis of panel parametric sensitivity on the radiated noise due to TBL excitation is also presented for a comparison.
Spatiotemporal variability of underwater sound fields near steep slopes
Authors: Duda Timothy F. , Lin Ying-Tsong , Zhang Weifeng Gordon , Ponte Aurelien , Cornuelle Bruce D.
Published: April 2012

Studies using idealized bathymetry have shown that steep slopes can have important effects on the geometric structure of ocean sound fields. Other studies have provided insight into the temporal variability of sound fields in the moving ocean. There is a general understanding that both effects occur together in the ocean, but their relative importance is not fully known, nor is the way they interact. The processes are often linked because slopes can generate strong internal tides and waves. Here, the coupled spatial and temporal variability is investigated using time-stepped three-dimensional (3.5-D) sound propagation modeling. The needed ocean sound-speed information is generated using modern regional ocean modeling. Solutions of the 3D parabolic acoustic wave equation are generated for a few hundred hertz. The spatial patterns of sound reveal that temporal intensity variation (scintillation) caused by internal tides can be enhanced at areas where sound encounters steep slopes. The magnitude of the effect is measured by repeating the simulations with a smoothed seafloor substituted for the realistic seafloor. The effect of internal tide strength on the interaction is quantified similarly. The effects of tide strength and seafloor steepness on spatial patterns of the sound field horizontal correlation length are also investigated.
Study on inverse problem of acoustical resonance scattering by elastic shells
Authors: Fangyong Wang , Zhengliang Cao , Shuanping Du
Published: April 2012

For the complexity of the analytical expressions for acoustical scattering by even the most simplistic elastic bodies such as spheres and cylinders, inversion of the exact direct problem in analytical way is almost infeasible. So, this paper mainly studies the inverse problem in a numerous way. Low-frequency(ka<50) resonance spectra of targets with varied parameters including longitudinal wave velocity, shear wave velocity, material density and shell thickness are theoretically calculated using Resonance Scattering Theory(RST), and in what way the elastic parameters affect the resonance signature is analyzed and concluded. The results obtained have great significance on active classification research based on acoustical resonance scattering.
Soundscape study for the improvement of neonatal intensive care units
Authors: Nelson Jennifer , Siebein Gary
Published: April 2012

Guidelines for healthcare spaces address day and nighttime Leq and peak levels. However, there are many complex and transient sounds that make up the overall sound levels in healthcare environments. Many of these sounds contribute to the background level, while others are transient noises and alerts to professionals who must hear them to care for their patients. Unfortunately, these noisy environments are also where the patient is placed to heal. Three different Neonatal Intensive Care Units (NICUs) built in different years in Florida were observed and categories of sounds in each were documented. Overall level vs. time measurements made over a one week time period in each NICU were compared with WHO guidelines. Spectral level measurements of individual and combined sounds are also documented in each NICU. The individual sounds were classified into necessary and unnecessary criteria that orchestrate at all times of the day by observing and documenting them. The results of this study show how changes being made in the design and operation of contemporary NICU's are reflected in the measured sound levels, and what future changes can be made to further decrease unwanted noise.
Evidence based design for hospital corridor noise control—Center for Health Design
Authors: Roy Kenneth , Browne Sean
Published: April 2012

Armstrong participated as a member of a joint research group including the Center for Health Design and Palomar Pomerado Health in San Diego, California. The goal of this research was to evaluate the effects of flooring and ceiling choices on Corridor Activity Noise, and its perception by both patients and healthcare professionals for 2 material choices: 1. corridors with carpet and standard acoustical ceilings, and 2. corridors with hard flooring and high performance acoustical ceilings. This work was managed jointly by the PPH and CHD, the acoustic measurements were taken by CMSalter Associates, and materials and some data analyses were provided by Armstrong. Test results showed that substitution of a hard surface flooring material for carpeting resulted in a net increase in corridor noise levels with the expected patient and medical professional perceptions of increased annoyance and distraction. However, if the hard surface flooring is combined with a high performance acoustical ceiling, then the rise in noise due to the floor surface is negated with the added absorption of the improved ceiling, such that the result is equivalent in level and perception by both patients and staff.
Experimentally investigated sleep disturbance of intensive care unit sounds
Authors: Persson Waye Kerstin , Wallenius Richard , Elmenhorst Eva Maria , Pedersen Eja
Published: April 2012

Patients at intensive care often report fragmented sleep from noise due to care activities from personal, from other patients and alarms. The aim of this study was to explore the effects of original and modified intensive care noises on sleep in 15 healthy subjects. Their sleep was registered with polysomnography during four nights, one adaptation night, one control night and two exposed nights with similar equivalent sound levels of 47 dB LpAeq, but with either a maximum sound pressure level of 64dB LpAFmax or 56 dB LpAFmax. The subjects also answered questionnaires and saliva cortisol was sampled in the morning. The results showed that during exposure nights, subjects had less slow wave sleep and spend more time awake. No relation was found between arousals and maximum sound levels. Apart from an unexpected reduction of time in the REM-stage for the exposure with lower maximum level, there was no impact of the reduction of maximal levels for the sleep parameters recorded. The subjective data supported the polysomnographical findings while cortisol levels were not affected by the conditions. For healthy subjects the reduction of maximal levels from 64dBA to 56 dBA was not enough to improve sleep quality.
Findings on bat sonar through Telemike system
Authors: Riquimaroux Hiroshi , Hiryu Shizuko
Published: April 2012

In order to understand how bats conduct echolocation recording what they listen to is essential. Then, we developed an onboard wireless telemetry microphone system (Telemike) for flying bats in our flight chamber. We also developed a sensitive microphone array system for field recordings and for the flight chamber. Some data through microphone array with Telemike will also be introduced. Both CF-FM (Hipposideros turpis, Hipposideros terasensis and Rhinolophus ferrumequinum nippon) and FM bats (Pipistrellus abramus, Miniopterus fuliginosus, and Eptesicus fuscus) were used in the flight chamber experiments, while only FM bats (Pipistrellus abramus and Eptesicus fuscus) were used for the field experiments. In the flight chamber experiment, through Telemike Doppler-shift compensation was confirmed from flying CF-FM bats. Echo amplitude compensation was found in both FM and CF-FM bats. The bats can fly without any collision against walls or their conspecifics in a narrow space. Telemike has recorded overlapped echoes originated from adjacent bats. How they extract weak echo signals in the situation where own echoes are masked by echoes of other bats may be revealed by Telemike experiments. Further, how bats get information from extremely weak echoes coming from a flying small insect will also be clarified in our experiments with Telemike. [Research supported by ONR grant]
Investigation of timbre saliency, the attention-capturing quality of timbre
Authors: Chon Song Hui , McAdams Stephen
Published: April 2012

Timbre saliency is defined as the attention-capturing quality of timbre. Saliency differences between timbres were measured using a tapping technique in which the stronger beat in ABAB isochronous sequences was reproduced by the listener, the idea being that the more salient timbre would capture listeners' attention and be chosen more often as the strong beat. A timbre saliency space was defined in which the distance between a pair of timbres corresponded to the difference in timbre saliency. Stimuli were generated with 15 orchestral instruments, equalized in pitch, loudness and duration. Data from 40 participants yielded a one-dimensional CLASCAL solution with two latent classes and specificities. Latent class structure shows no relation with gender, musicianship or age. Testing audio descriptors from the Timbre Toolbox [Peeters et al., 2011, J. Acoust. Soc. Am., 130, 2902-2916], the odd-even harmonic energy ratio explains 51% of the variance along this dimension. A combination of tristimulus (band 3) and odd-even ratio explains 73% of the variance in the mean saliencies of individual sounds across all other comparison sounds. Mean saliency thus seems to depend on the high-frequency harmonic energy and spectral envelope jaggedness, whereas saliency comparisons between timbres depend more on spectral envelope jaggedness.
A distributed array processing using multi-channel signals over a network with an embedded time code by the network time protocol
Authors: Chisaki Yoshifumi , Mashima Tomohisa , Usagawa Tsuyoshi
Published: April 2012

A conventional microphone array system uses a conductor to wire from a microphone to an input via an amplifier. While, a wireless transmission for an array system makes the configuration flexible, and it is expected to provide novel applications widely, such as measuring of impulse response in wide area. One of the issues is a synchronization of time between channels. This paper proposes multiple signals transmission system over a network with a time code embedding to synchronize those signals. The system consists of clients and a server. Each client at a receiving point runs a network time protocol client daemon, and a packetized audio signal with a time code is sent to a server. The signal from a client is reconstructed at a server based on the time code. Since the time differences between clients affects to performance of the multichannel signal processing, small error in time at a client is preferred. This paper discusses how the error in time between channels affects to performance of the distributed microphone array system.
The realistic- reverberation sensation in 3-D acoustic sound field reproduction with parametric loudspeakers and indirect non-parametric loudspeakers
Authors: Tsujii Hideya , Morise Masanori , Nishiura Takanobu
Published: April 2012

In the field of virtual reality, mixed reality (MR) has recently been drawing attention as a technology to experience the virtual space by superimposing the computer graphics (CG) objects in real space. The technologies to reproduce 3-Dimensional (3-D) acoustic sound fields in conjunction with MR can especially experience a higher realistic sensation than the conventional MR. A parametric loudspeaker based on an ultrasound with the higher directivity can reproduce 3-D acoustic sound fields by designing a sound image. However, it is difficult to present the realistic sensation depending on the reverberation, because an acoustic wave emitted by it shouldn't diffuse in the room. In this paper, we newly proposed to reproduce 3-D acoustic sound fields utilizing multiple parametric loudspeakers and indirect non-parametric surround loudspeakers for realizing the realistic- reverberation sensation. It could realize a higher realistic- reverberation sensation without affecting the sound image localization. The effectiveness of the proposed method was assessed by the subjective evaluation experiments for the realistic- reverberation sensation and the sound image localization. As a result, we confirmed the effectiveness of the proposed method.
Realtime face recognition system with ultrasonic sensing
Authors: Cao Benxi , Wang Jingyao , Wang Yang , Xu Yong , Yang Jun
Published: April 2012

Unlike vision-based approaches, ultrasonic sensing systems have the ability to obtain the object distance and echo energy information. With the development of airborne ultrasonic detection, ultrasonic face recognition has been discussed. However, the existing ultrasonic face recognition systems store the echo waveform data and make processing and analysis afterwards. Seperated acquisition and analysis procedures make these systems non-realtime. In this paper, a realtime ultrasonic face recognition system is proposed. The system has the following functions: signal generation, transmitting, receiving, amplification, demodulation, spectral analysis, and feature extraction. A continuous wideband ultrasonic signal is transmitted, then the geometrical information can be extracted from the echo signal, and suitable pattern recognition methods are used to recognize human face. The system can implement realtime face recognition with ultrasonic sensing, and a considerable recognition rate is achieved.
Non-Rayleigh reverberation statistics
Authors: Chotiros Nicholas
Published: April 2012

In sonar reverberation, the superposition of numerous scattered sound waves tends to produce a Rayleigh distribution, consistent with the Central Limit Theorem. Causes for deviation from the Rayleigh model are identified as sonar configuration and environmental variability. In the former, the sonar configuration determines the number of scatterers in each resolution cell, and when the number is too small, the Central Limit Theorem is violated. In the latter, the total environment may be considered as a patchwork of local environments that are resolvable by the sonar system, but not reliably distinguishable due to positional inaccuracies and overlap in the range of reverberation amplitude values. In that case, the resulting ensemble may have a probability distribution function that is a mixture of the probability distribution functions of the local components. The patchiness of the environment determines the number of components and their proportions in the mixture. The issue of stationarity in the context of a patchy environment is an important concern. Although the reverberation from a patchy environment is, strictly speaking, non-stationary, the perception of stationarity may be achieved. [Work supported by the Office of Naval Research, Ocean Acoustics].
The role of early reflections for definition and source separation
Authors: Kuusinen Antti , Pätynen Jukka , Robinson Philip , Lokki Tapio
Published: April 2012

The density and spatial distribution of early reflections change the perception of individual instruments in an orchestral concert. Here, we present results of a listening test that aims to find the role of early reflections to perceptual phenomena related to source separation. The stimuli are anechoic symphony orchestra recordings convolved with different impulse responses that comprise of simulated direct sound and early reflection patterns combined with the late reverberation measured from a real hall. The differences between samples are investigated with various listening test methods, enabling the simultaneous comparison of samples. Quantitative data are also collected with the applied test methods. The results are expected to confirm our hypothesis that listeners can distinguish individual instruments better if the early reflection patterns in conjunction with individual sources differ more from each other.
Three dimensional representation method for a public indoor soundscape with multiple sound sources
Authors: Shimizu Yasushi , Furuya Hiroshi
Published: April 2012

The author has been investigating an evaluation method of a reproduced sound such as paging sound, background music and so on in a public space. The current acoustical descriptors for an evaluation of such sounds, which are played to deliver information and attention to the people, have a difficulty to apply to multiple sounds environment. This report describes a new evaluation method which utilizes drawing an indoor soundscape with multiple sounds from listening experience, based on major aural impressions such as Loudness, Timbre, Apparent Sound Source Width, horizontal and vertical Sound Localization, Distance Perception, and Perspicuity, “KIWADACHI”. This will be applied to describe the Indoor Sound Environmental Character with multiple sound sources. The evaluation tests with this tool are carried out in the indoor sound environments of a retail shop, regarding aural impression of Perspicuity for the sound reproduction. And the results of both the subjective representation in the indoor sound environment and the acoustical descriptor of speech intelligibility are presented for the reproduced sound.
Loudness asymmetry in real-room reverberation: cross-band effects
Authors: Raimond Andrew , Watkins Anthony
Published: April 2012

Although room reverberation adds sizeable “tails” at the ends of sounds, they are not prominent for listeners. Evidence for this comes from loudness judgements of stimuli with envelopes having fast onsets and slow offsets, thereby resembling sounds with reverberant tails. Such sounds are less loud than their reversed counterparts, and this difference is more substantial when the test-sound is preceded by a “standard” sound that has a similarly “tail-like” offset. A perceptual constancy may be responsible; one where sounds with decaying tails are “parsed” to separate source characteristics from effects of reverberation, and to discount energy in tails from listeners' judgements. Indeed, this “loudness context effect” is even more substantial when real-room reverberation is used. Here we ask whether the effect is restricted to the frequency region occupied by the context; conditions where standard and tests occupy the same narrowband frequency region are compared with “cross-band” conditions, where the standard and test have widely separated frequency regions. Results show that the effect is markedly reduced in cross-band conditions, indicating that the perceptual constancy responsible is a “within band” phenomenon. Similar within-band characteristics are also evinced by a form of constancy in speech perception, where the salience of “tails” from reverberation is also reduced.
High-frequency sound communication in the concave-eared frog
Authors: Shen Jun-Xian
Published: April 2012

The concave-eared torrent frog, Odorrana tormota, is an arboreal, nocturnal frog living near noisy fast-flowing streams in Huangshan China. Recordings in the field show that males produce diverse melodic calls containing spectral energy extended to the ultrasonic range. Playbacks of the audible as well as the US components of a male call can evoke males' vocal responses. Auditory evoked potentials from the auditory midbrain confirm that males possess the US hearing capacity. Before ovulation, gravid females produce high-frequency short calls, which elicit vocalization and precise positive phonotaxis from males. Acoustic playbacks of male's calls also evoke vocal responses and phonotaxis from females, but the females show no ultrasonic sensitivity. This suggests that the high-frequency sound communication system has evolved in the frog species. [Work is supported by the National Natural Science Foundation of China (NSFC grants Nos. 30570463 and 30730029 to J.-X.S.]
Nonlinear resonant ultrasound spectroscopy is sensitive to the level of cortical bone damage
Authors: Haupert Sylvain , Guérard Sandra , Mitton David , Peyrin Françoise , Laugier Pascal
Published: April 2012

The objective of the study was to evaluate the sensitivity of nonlinear resonant ultrasound spectroscopy (NRUS) measurements to the accumulation of damage in cortical bone by fatigue or by controlled crack propagation. Two groups of human cortical bone specimens were prepared from the femoral mid-diaphysis. The specimens from the first group were taken through a progressive fatigue protocol consisting of four steps of cyclic four-point bending. The specimens from the second group were taken through a toughness protocol consisting of initiation and controlled propagation of a stable crack induced by 4-point bending mechanical loading. Our results evidenced a progressive increase of the normalized nonlinear elastic parameter during fatigue testing or during toughness experiments. While in specimens subjected to mechanical fatigue cycling the relative variation of nonlinear elasticity was significantly related to the relative variation of the number density of small cracks assessed with micro-computed tomography, in crack propagation experiments a significant relationship was found between the level of nonlinearity and total crack length. These results strongly suggest that NRUS measurements are sensitive to damage accumulation and can be used as a marker of bone damage.
Effects of boundary conditions on the two wave phenomenon in cancellous bone
Authors: Matsukawa Mami , Mizuno Katsunori , Nagatani Yoshiki
Published: April 2012

After the successful observation of two wave phenomenon in cancellous bone, wave characteristics have been investigated by in vitro studies. However, there still exists strong necessity to understand the effects of bone boundary conditions on the phenomenon, because the cancellous bone is always covered by a cortical layer in vivo. This paper is dedicated to the experimental and simulation studies of the effects on the two wave phenomenon. A sample of cancellous bone (76.1x45.2x12.9 mm3) and two cortical plates (thickness: 1.2 and 1.9mm) were obtained from the left radius of a racehorse. Longitudinal pulse waves around 1MHz were measured by a conventional ultrasonic pulse technique using PVDF transducers. With 3-D CT image of the sample, wave propagation was also investigated by a 3-D elastic FDTD method. We then compared wave propagation in the sample covered with cortical layers or not. In both experimental and simulation approaches, two wave phenomenon was observed in the covered sample. However, the slow wave amplitude was very sensitive to the interface conditions between the cancellous bone and cortical layers. In addition, the waves often became small due to the conditions, telling the importance of sensitive wave observation in some cases.
Non contact long distance exploration method for concrete using SLDV and LRAD
Authors: Sugimoto Tsuneyoshi , Akamatsu Ryo , Utagawa Noriyuki , Tsujino Syuichi
Published: April 2012

The hammering test is a representative method in inspection for cavities and delaminations at shallow area of concrete surface. Although this method is used widely because it is not expensive, efficiency of the defect-judging largely depends on the tester's experience and long measurement time is necessary for wide area inspection. Other methods have been developed, however, it is necessary to contact or approach to the inspection object during a measurement. Therefore, we propose a new non-contact acoustic imaging method for nondestructive inspection using scanning laser Doppler vibrometer (SLDV) and long range acoustic device (LRAD). In this method, Surface vibration, which is generated by air borne sound, is measured using SLDV. This time, the styrofoam board was buried at shallow depth in the concrete are used as a substitute of a cavity in the concrete. As an experimental result, a styrofoam board is clearly imaged by the vibration velocity of the concrete surface. Furthermore, we confirmed that our proposed method can apply even 10 m away distance, and the measurement distance is about within 20 m under the present conditions. It means that the non destructive inspection for concrete from a long distance is possible.
Wavelength measurement of guided waves in plates with electromagnetic acoustic transducers
Authors: Zhai Guofu , Jiang Tao , Gong Jiapeng , Kang Lei
Published: April 2012

For an EMAT (electromagnetic acoustic transducer) with a meander-line coil, the interval spacing between adjacent wires of the coil is generally designed to be the half wavelength of guided waves excited by the EMAT. However, the actual value of the wavelength deviates from the double interval spacing (double spacing) because of the variation spectrum of the spacing and the bandwidth of excitation frequency. So it is difficult to obtain the actual value of the wavelength of guided waves in plates. Based on dispersion equation and group velocity equation of guided waves, we find that the actual value is double spacing when the frequency of the excited signal is equal to the frequency of the received one; and the actual value deviates from the double spacing when the EMATs' operating points are not on the dispersion curves. Taking SH wave EMATs for instance, this paper proposes two wavelength measurement methods with different initial conditions for SH waves in plates. The validity of the proposed methods is verified by experiments.
Instantaneous tracking of a monopole sound source using algebraic localization method and circular array
Authors: Levy Tsukassa , Ando Shigeru
Published: April 2012

The purpose of this study is to localize instantaneously and to track sound source using circular array. Localization is done using a novel explicit inversion formula of direction and distance of a monopole source [S. Ando, ASA Seattle Meeting, 2011]. This method consists in applying the weighted integral method (IEEE Trans. SP, 57, 9, 2009, Inverse Problems, 26, 015011, 2010) on a partial differential equation (PDE) satisfied by the sound wave. In this study, we consider the location-constraint PDE (ASA/ASJ meeting, 2006) that describes the unilateral propagation of wide-band waves from a single source. We also take into account reverberation in this study by using a simplistic model of room reverberation. In the experiments, loci of instantaneous localization results are displayed on a motion image captured by a TV camera mounted on the 16-element circular array. Several experimental results are shown to demonstrate time-resolved localization capability of a multiply reflected source. Some theoretical and experimental comparisons with and without reverberation will be given.
Mass sensing using a functionalized subordinate oscillator array
Authors: Vignola Joseph , Judge John , Glean Aldo , Ryan Teresa
Published: April 2012

Vibrometric based mass sensing for detection of trace levels of chemical vapors has been under investigation for a number of years. One implementation of such a sensor uses a vibrating MEMS cantilever that has been functionalized to bind with a specific chemical compound. The additional mass reduces the resonance frequency of the structure by an amount that can be related to the concentration of the compound. This work describes an analytic and numerical study of an array of differently functionalized cantilevers coupled to a primary structure. The dimensions of individual cantilevers are chosen such that there is a distribution of their isolated natural frequencies and the mass of the primary structure is substantially larger than the collective mass of the subordinate cantilevers. The isolated natural frequencies of the cantilevers must be packed around that of the primary structure such that the response curves of neighboring cantilevers cross near their half power points. This overlap ensures an exchange of energy between array elements. Results describing optimized distributions of cantilever properties will be presented. Both fabrication variations and the sensed mass are considered as disorder in the system. This presentation reports how the relative magnitude of these disorders affects mass declarations.
Spatial variability of timbre for an electric guitar amplifier
Authors: Case Alexander , Roginska Agnieszka , Anderson Jim
Published: April 2012

Impulse response measurements of an electric guitar amplifier at high spatial resolution reveal frequency response variabilities likely to drive key elements of timbre for the recording engineer. Data collection from the very near field of the driver to a distance of several feet away, gathered in a three-dimensional grid around the open-backed, single-driver, Fender Deluxe electric guitar amplifier quantify the variations in frequency response which may be exploited by the recording engineer using microphone placement to influence timbre.
Open-loop control of a robotized artificial mouth for brass instruments
Authors: Helie Thomas , Lopes Nicolas , Causse René
Published: April 2012

In order to have reproducible and controllable experiments, a robotized artificial mouth dedicated to brass instruments has been developed (CONSONNES project of the French National Research Agency). The actuators control: (A1) the airflow, (A2) the mouth position (monitoring the lips force applied to the mouthpiece), (A3-4) the water volume in each lip (water-filled latex chamber). The sensors measure: (S1-2) the pressure in the mouth and the mouthpiece, (S3: optical sensor) the area between the lips, (S4) the force lips/mouthpiece, (S5-6) the water pressure in each lip, and (S2bis-S4bis) the position of the moving coils (A2-4). We present an open-loop control obtained from measures, according to the following steps. First, a calibration for the lips control is performed, by analyzing signals (S4-6) w.r.t. positions (S2bis-S4bis), with no airflow. Second, slowly time-varying calibrated commands (A2-A4) are used to obtain quasi-stationary regimes (non oscillating, quasi-periodic, etc), for constant airflows. Third, a sound analysis is processed to generate cartographies of features (energy, fundamental frequency, etc) w.r.t. to the calibrated control parameters. This exploratory tool allows to build a dictionary of relevant control parameters from which basic sequences of notes can be played, and during which all the signals (S1-6) can be recorded.
Simulation of `Suikinkutsu' sound considering sound radiation from water surface
Authors: Fujita Yuki , Wakatsuki Naoto , Mizutani Koichi
Published: April 2012

This paper is about a `Suikinkutsu', a kind of Japanese traditional musical instruments. Different from other musical instruments, `Suikinkutsu' is composed of an upended jar buried underground in the garden. Dropping water into `Suikinkutsu' works as sound source, and attracting harp-like sound inside the jar, `Suikin-on', is generated. Although the sounding mechanism of `Suikinkutsu' is interesting because there are complicated interactions among air, water, and jar made of ceramic to generate harp-like beautiful sound, its analysis has not been achieved yet. To investigate the sounding mechanism of `Suikinkutsu', simulation of interaction between air and water is performed. The obtained results suggest that the water in the jar contributes to sound generation of `Suikinkutsu'.
Active control on the scattered radiation by a rigid surface
Authors: Han Ning , Qiu Xiaojun
Published: April 2012

An approach for predicting the scattered sound pressure in one- and three-dimensional sound field is proposed by measuring the total sound pressure on a rigid scatterer surface, which is further used as an error sensing strategy in an active noise control (ANC) system to reduce the scattered radiation. Experiments are carried out to validate the prediction method, and a single channel broadband feedforward ANC system is implemented to suppress the impulsive scatterance at the observation point. It is found that the ANC system based on the proposed prediction method is effective. About 12.2 dB reduction of the impulsive scattered radiation is obtained in one-dimensional sound field, and 8.2 dB reduction in three-dimensional sound field. ACKNOWLEDGMENTS The authors would like to acknowledge the support NSFC (Project 11104141 ).
Case study of applying active noise control on communication chassis
Authors: Zou Haishan , Yu Di , Qiu Xiaojun
Published: April 2012

In some communication chassis, running of the cooling fan causes the noise emission level of the chassis exceed the upper limited level of the standards and regulations. In this case study, various sound transmission paths are indentified, such as the structure borne sound transmission, the air intake and the air outtake, etc. To reduce the direct noise, a metal enclosure which divided into several ducts and with new intake and outtake on its surface is used to cover the chassis. The wall of ducts is equipped with absorbing material to form mufflers, so the middle and high frequency noise is reduced successfully. The key point is that the active control systems are installed in the ducts to reduce the low frequency noise. A noise level reduction of 6-8 dB is achieved with this active-passive hybrid method. However, it is found that it is impossible to achieve such a reduction level without using active noise control because of the abundant low frequency component of the noise.
Assessment of the effectiveness of adaptive active vibration control for the minimisation of radiated sound from panels
Authors: Wareing Robin , Pearse John
Published: April 2012

In many practical situations noise is radiated from a noise or vibration source into adjacent areas through vibration of plates. This paper is concerned with the reduction of this radiated noise via active vibration control of such panels. An LMS based adaptive controller is implemented and the experimental results are compared to an ideal model of the noise reduction, this allows the effectiveness of the adaptive controller to be assessed. The plate used in tests is a 1546mm by 946mm simply supported panel. This has been modelled in Matlab allowing the sound field above the plate to be evaluated. Using the theories developed by Nelson et al [1] the theoretical optimal noise reduction can then be calculated. The panel is excited via a point force; the sound pressure at a number of points is then measured. The active control is actuated via a coil based inertial actuator. The sound pressure is measured following the implementation of active control, thus allowing the practical noise reduction to be calculated. 1. Fuller, C.R., S.J. Elliott, and P.A. nelson, Active Control of Vibration. Vol. 1. 1996, London: Academic Press Limited. 332.
Soundscape: its theory and praxis in Chinese classical garden
Authors: Yuan Xiao-mei , Wu Shuo-xian , Wu Yan
Published: April 2012

In this paper, an unique soundscape concept in Chinese classical garden is explicated from theory and praxis levers, which is based on the traditional “Harmony” culture, with the philosophical background of Confucianism, Taoism and Buddhism, and the character of the aesthetic refining and gardening construction experience together up. The general aim of which is creating a artistic conception with nature aesthetics and poetic culture to conduct people's life to archive the highest state. This paper firstly introduces the formation and development of the concept of Chinese classical garden soundscape, and its related social and cultural reasons are investigated as well. And then, the technical logic contained in garden construction rules are sorted out. So the unique characteristic of soundscape theory and praxis in Chinese classical garden are explicated. Key Words: Chinese Classical Garden; Soundscape; Theory; Praxis