bluuebunny/crossref_metadata_2025 huggingface dataset:
Underwater acoustic detection and classification for cetaceans' vocalizations of Marine Observatory in the Northeastern Taiwan (MONET)
Authors: Fang Yin-Ying , Wu Kao-Chao , Chen Chifang
Published: April 2012

Passive acoustics is as an important tool for observing marine animals and long-term underwater environment monitoring. Since the amount of data is enormous, an effective auto-detector to select critical features and classify their patterns from the recorded acoustic signal. In this study, we had developed an automatic detector with both the feature extraction and classification modules. In the feature extraction module, we select features from the energy and end-point of the time signal in needed. Then, we normalized the extracted features as inputs for the classification module based on the theory of back propagation neural network (BPNN). The BPNN will be trained and tested using both the cetaceans' acoustic signals which recorded from the hydrophone of Marine Cable Hosted Observatory (MACHO system) until the network becomes stable and convergent. Identification objects are chosen commonly seeing cetaceans from the northeastern offshore of Taiwan, Guishan Island. The detector is a robust tool which has good recognition rate for classifying cetaceans. It supersedes the experienced human operators due to less time consuming and low labor cost. (sponsored by National Science Council of Republic of China under project “Marine Observatory in the Northeastern Taiwan (MONET)” No. NSC 100-2221-E-002-027)
Behavioral in-air audiogram of two Arctic fox (Alopex lagopus) at the Columbus Zoo and Aquarium
Authors: Stansbury Amanda , Thomas Jeanette , Stalf Colleen , Murphy Lisa , Lombardi Dusty , Carpenter Jeremy , Mueller Troy
Published: April 2012

The aerial audiograms of two captive adult, male Arctic fox (Alopex lagopus) were measured using a two-alternative, forced-choice paradigm and descending staircase method of signal presentation at the Columbus Zoo and Aquarium. Both fox displayed a typical mammalian U-shaped audiometric curve, with a functional hearing range of 125 Hz to 16 kHz (sensitivity < 60 dB re: 20 μPa) and average peak sensitivity of 22 dB re: 20 μPa at 4 kHz. This range is similar to airborne hearing thresholds previously measured for two closely related species, the kit fox (Vulpes marotis) and the domestic dog (Canis familiaris). There was little variability around threshold and no significant difference between the hearing curves of the two fox. The peak sensitivities of the Arctic fox overlaps their vocal range, the vocal range of their prey; field voles (Microtus agrestis), collared lemmings (Dicrostonyx groenlandicus), Canada geese (Branta canadensis), and the hearing range of a predator; the polar bear (Ursus maritimus). Ambient noise levels were monitored and test frequencies below 5 kHz were possibly masked. Potential response bias was examined using Receiver Operator Characteristic analysis and had a conservative bias. Masking effects and conservative response bias may have resulted in slightly underestimated hearing curves.
Charactarization techniques of particular proteins in cerebellar cortex using acoustic impedance microscope
Authors: Yoshida Sachiko , Minowa Ryoichi , Masaki Shiho , Yamamoto Seiji , Kobayashi Kazuto , Hozumi Naohiro
Published: April 2012

Two-dimensional acoustic impedance imaging is useful for observation of living organs without invasion. Because acoustic impedance is proportional to sonic speed and density, organelle having larger density, e.g. nucleus, showed higher impedance. We have proved that cerebellar cortical layers and Purjinje cell bodies were identified using the acoustic impedance microscopy. In order to visualize the distribution of specific functional proteins in acoustic imaging, we proposed direct or complex-including heavy metal treatment to elevate the density and acoustic impedance of a particular protein. Heavy metal binding was useful for acoustic impedance imaging; however, metal binding to a protein molecule was not always specific. To observe the distribution of wanted molecules, we investigated two types of heavy metal binding materials; one was p-cymene ruthenium (Ru)-binding calcium channel binding peptides, and another was cadmiun nanocrystal binding antibodies, QdotTM. We could observe the characterized acoustic area by both p-cymene Ru-binding peptide treatment and Qdot treatment, whereas specimen plate was required hydrophobic condition to stabilize acoustic impedance. We suggest that a metal-binding reagent would be useful for specialization of an acoustic imaging.
Experimental and theoretical characterization of high frequency polymer ultrasound contrast agents
Authors: Anastasiadis Pavlos , Chitnis Parag , Brand Sebastain , Lorenz Georg , Ketterling Jeffrey , Allen John
Published: April 2012

Lipid-shelled contrast agents have been the focus of combined experimental and theoretical efforts in order to characterize their dynamics with respect to shell material parameters. The use of independent mechanical measurements such as atomic force microscopy (AFM) for the shell materials has begun to receive attention. Polymer-shelled agents are less understood in terms of behavior and their destruction scenarios are exemplified by complex buckling modes. We present ultra-high frequency (GHz) scanning acoustic microscopy (SAM) measurements of polymers (Philips Healthcare, Best, The Netherlands) with various shell elastic properties and their corresponding thicknesses. Acoustic microscopy offers unique advantages in terms of non-invasive microscale measurements and visualization of the agents. The obtained material parameters are used in numerical simulations to predict pressure thresholds for the onset of the sub-harmonic response.
Ray tracing of acoustic wave in the lossy atmosphere
Authors: Song Yang , Zhou Chen , Zhao Zhengyu , Zhang Yuannong
Published: April 2012

An acoustic ray tracing model considering the real atmospheric acoustic attenuation is developed base on the equation of the acoustic local dispersion relation in the stratified atmosphere. The acoustic attenuation coefficient and growth factor in the moving atmosphere are deduced from the imaginary part of the dispersion relation, and the acoustic attenuation coefficient is corrected by using the theory of attenuation in the real atmosphere. The ray equations in the lossy atmosphere are obtained through Hamilton equations. The numerical study of this ray tracing model shows that the absorption of sound could have some influence to the acoustic trajectory. The influence could be neglected in the near field propagation but not in the far field.
Development of PZT piezoelements for simultaneous generation and reception of longitudinal and shear ultrasonic waves
Authors: Kazys Rymantas , Voleisis Algirdas , Zukauskas Egidijus
Published: April 2012

Ultrasonic methods are often used for measurement of various non-electric quantities, for example, pressure or displacements. In this case in order to increase accuracy of measurements longitudinal L and shear SH ultrasonic waves simultaneously propagating in solids along the same path must be used. For simultaneous generation/reception of L and SH waves dual mode PZT transducers may be used, but up to now only theoretical studies are known with a little experimental confirmation. A dual mode piezoelement can be manufactured as a rotated Z-cut element from a large thick PZT block. Objective of our study was investigation of transient processes in dual mode PZT piezoelements, optimization of their geometry and development of manufacturing technology. Vibrations of rotated Z-cut disc and rectangular shape piezoelectric elements in a pulse mode were investigated by a numerical modeling using ANSYS finite elements code. The volume of the disc was meshed using the SOLID5 elements. Modeling results were verified by experiments using steel measurement bodies and a good correspondence has been obtained. At the angle θ=36° L and SH waves of similar amplitudes are excited.
Radially composite cylindrical piezoelectric ultrasonic transducers
Authors: Lin Shuyu , Wang Shuaijun , Fu Zhiqiang
Published: April 2012

A new type of radially composite cylindrical piezoelectric ultrasonic transducers is presented and its radial vibration is studied. The composite transducer is composed of a radially polarized piezoelectric ceramic short tube with arbitrary wall thickness and a metal tube. The radial vibrations of the radially polarized piezoelectric tube and the metal tube are analyzed and their electro-mechanical equivalent circuits are obtained. Based on the mechanical boundary conditions between the piezoelectric tube and the metal tube, the six-port electro-mechanical equivalent circuit of the radially composite ultrasonic transducer is obtained and the frequency equation is given. The theoretical relationship between the resonance/anti-resonance frequency and the effective electro-mechanical coupling coefficient with the ratio of the inner radius over the outer radius of the composite transducer is analyzed. At the same time, the radial vibration of the composite transducer is simulated by using Finite Element Method. The vibrational modal shape and the harmonic response are given numerically. At last, some radially composite ultrasonic transducers are designed and manufactured; their resonance/anti-resonance frequencies are measured. It is shown that the analytical resonance/anti-resonance frequencies are in good agreement with the numerically simulated and experimental results. It is expected that this type of radially composite ultrasonic transducers can be used in large scale ultrasonic liquid processing, such as ultrasonic extraction, ultrasonic sonochemistry and other applications where large radiation surface and ultrasonic power are needed.
Modeling and optimization of a shotgun condenser microphone
Authors: Bai Ming-Sian
Published: April 2012

This paper is focused on modeling and optimization of a shotgun microphone that is known to be a highly directional acoustic pick-up. A lumped-parameter model is established, with the aid of Zuckerwar's approach, to predict the frequency response of the condenser microphone. On the basis of the model, we use the simulated annealing ([SA]) method to optimize the microphone parameters, including the diaphragm radius, the diaphragm thickness, the air gap distance and the volume of back chamber, such that the sensitivity is maximized subject to a desired bandwidth. In our modified approach, the air gap resistance (Ra ) and the back chamber compliance (Cbc ) are used to calculate the D factor in Zuckerwar's model. To model the shotgun tube, T circuit and two-port network are utilized in formulating transfer matrices that is then converted to an impedance matrix representation. In addition, an array model is established to simulate the directional response. The results revealed that the shotgun microphone is highly directional at high frequencies, while the on-axis frequency response is influenced by the acoustic resonances of the tube. The simulation results suggest that the tube length should be greater than half of the wavelength, whereas and the spacing between holes should be less than half of the wavelength.
An experimental and analytical application of vehicle sound quality target cascading
Authors: Kang Koo Tae
Published: April 2012

To achieve pre-defined sound quality target in a cabin, the interior sound is decomposed into air-borne and structure-borne sound by using transfer path analysis. First, the air-borne sound target is cascaded to the target of each sound package component in the form of the transmission loss mainly in the analytical way. Second, for the structure-bone sound, the experimental noise transfer path analysis is extended to identify the sensitive structural path for specific frequency contents as opposed to the traditional methods with which the critical structural components are hard to identify. As a result, the vehicle sound target proved to be successfully cascaded to the component level target by applying aforementioned methods.
Proposed hybrid multiple look approach for calculating unsteady loudness
Authors: Ule Helen , Novak Colin , Gaspar Robert
Published: April 2012

Experimental studies have shown that for short gaps between 2 to 5 ms, the perceived loudness is higher than for uninterrupted noise presented to the ear. Other studies have also shown that the present temporal integration models for the calculation of time varying loudness do not adequately account for short duration phenomena. It has been proposed that the multiple look approach is a more applicable method for describing these short term circumstances. This approach breaks a sound into very small durations which allows for the intelligent processing of the looks and decision making depending on the nature of the stimulus. However, present technologies, such as the Fast Fourier Transform, are not adequate to deal with short duration sounds across the entire frequency spectra. A compromised approach using a proposed hybrid model is presented to account for perceived loudness levels for sounds in the presence of gaps while using an integration model. This hybrid multiple look model was tested using several sounds including mechanical and speech sounds and was found to perform as intended.
Annoyance from railway vibration in residential environments: factors of importance when considering exposure-response relationships
Authors: Peris Eulalia , Woodcock James , Sica Gennaro , Moorhouse Andy , Waddington David
Published: April 2012

Railway induced vibration is an important source of annoyance in residential environments. Annoyance increases with vibration magnitude. However, these correlations between annoyance and physical ratings are weak. This suggests that vibration-induced annoyance is governed by more than just vibration level, and that simple exposure-response relationships alone sometimes do not provide sufficient information for understanding the wide variation in annoyance reactions. Results of investigations made on factors coming into play when considering an exposure-response relationship between level of vibration and annoyance are presented here. Examples of these factors are time of day, situational factors, personal and attitudinal factors. This was achieved using data from case studies comprised of face-to-face interviews (N=931) and internal vibration measurements collected within the study “Human Response to Vibration in Residential Environments” by the University of Salford. This work will be of interest to researchers and environmental health practitioners involved in the assessment of vibration complaints, as well as to planners and consultants involved in the design of buildings and railways. [Work funded by the Department for Environment, Food and Rural Affairs (Defra) UK]
Characteristics of effective noise regulations
Authors: Timmerman Nancy
Published: April 2012

In considering what is an “effective” noise regulation, the definition used will be that which actually reduces the noise regulated. Parameters which are expected to have an effect on the ability to reduce the noise include control over the noise source regulated, a way to measure results, and consequences or enforceability. Examples will be taken from community noise and airport noise regulations in the United States.
Research of aircraft noise evaluation and limits
Authors: Zhu Wenying , Zhou Yude , Chu Yiping
Published: April 2012

Along with the European Union to promote the day - and - night equivalent sound level DENL, a growing number of countries have adopted the equivalent sound level DNL or DENL instead of the traditional evaluation for airport noise evaluation, and in sensitive areas the maximum sound level limits was used, some also use the TALA (Time-above an A-weighted sound level threshold). China promulgated the “GB9660 - 88 measurement of aircraft noise around airport” and “GB9661-88 environment standard of aircraft noise around airport”, rating for the weighted equivalent continuous perceived noise level WECPNL, and it is independent of other acoustic environmental standard. The state environmental protection department proposed to revise the criteria. In this paper, based on the large amount of measured data, under the aircraft noise statistical analysis, trying to build the relationship between WECPNL, Leq, Lmax; combined with the research results of relationships between noise level and annoyance; investigating the suitability of the current criteria (evaluation and limits), and explore the establishment of a set of aircraft noise evaluation method, which can not only reflect the characteristics of aircraft noise, but also better associated with living requirements.
Experimental investigation of fluctuation characteristics caused by the interaction between turbulent boundary layer and the cavity on the trailing edge of cavity
Authors: Pang Yezhen , Yu Mengsa
Published: April 2012

The fluctuation characteristics caused by the interaction between turbulent boundary layer and the cavity on the trailing edge of cavity were investigated. Experiment results showed the fluctuation on the trailing edge of cavity is reinforced. Because the depth of cavity is smaller than the length of opening, the sheartone frequency will not approach the resonance frequency of the cavity, however the sheartone will reinforce the acoustic radiation of the structure downstream the cavity.
The study of sono-elasticity of floating bodies in the acoustical environment of shallow sea
Authors: Zou Ming-Song
Published: April 2012

A concept combining sono-elasticity research field with oceanic sound propagation research field in developed in this paper. The paper formulates in details about how to transfer the sono-elasticity dynamic equations together with oceanic sound propagation equations in theoretical model into related numerical program by using the PEKERIS neritic acoustic environment as an example. The further verification of this approach and related computing program, and analyses on characteristics of the structural vibration and acoustic radiation in neritic acoustic environment are also provided in the paper by analyzing the problem of a elastic spherical shell as an example. Keywords:Sono-elasticity; Sound propagation; Shallow sea; Spherical shell.
Study on hull vibration and underwater radiation noise induced by propeller excitation considering shafting alignment
Authors: Li Liaoyuan , Cao Yipeng , Zhang Wenping
Published: April 2012

The recent increases in the number, size, speed and horsepower of commercial ships led the ocean ambient noise levels at low frequencies increased. Accordingly, the analysis of ship hull vibration control and noise reduction needs to be paid more attention now. In this paper, a finite element model of bulk carrier including shafting is built. Considering the shafting alignment, the vibration and underwater radiation noise characteristics of hull structure caused by propeller excite force are calculated. Finite element method (FEM) is employed to simulate the vibration response of the hull structure due to the propeller excitation in consideration of fluid-structure interaction. Then the outer surface of the finite element model is treated as a boundary element model. Finite element solutions of the hull surface vibratory velocity are further used as velocity boundary condition of the hull boundary element model for consequent underwater radiated noise calculation with boundary element method (BEM). In addition, the characteristics of transfer force and radiated sound power of hull structure are obtained. Comparing with the numerical results of considering shafting alignment and without, the effect of shafting alignment on propeller-induced ship hull vibration and underwater radiation noise is analyzed.
The effects of intelligibility and variability on cognitive performance and acoustic comfort
Authors: Liebl Andreas
Published: April 2012

Open-plan offices are very popular due to some assumed economic and organizational advantages. These benefits are confronted with typical drawbacks, i.e. office noise and lack of speech privacy. Ambient speech caused by conversations of colleagues is assumed to impair office workers' individual task performance at silent, concentrated work. The Speech Transmission Index (STI) is proposed to be a predictor of how much performance is reduced due to ambient speech in dependency of its intelligibility (Hongisto, 2005). Target values for the acoustic quality of open-plan offices were defined which account for the special importance of speech intelligibility (e.g. Virjonen et al., 2009). Fluctuation strength, a hearing impression due to slow modulations of amplitude or frequency, has also been shown to predict the loss of individual task performance (Schlittmeier et al. 2011). The relevance of both variables is systematically explored with regard to cognitive performance and acoustic comfort. Based on these results target values are discussed.
The quiet office—noise abatement in office buildings by means of smart structures
Authors: Bein Thilo , Bös Joachim
Published: April 2012

Noise is a serious form of environmental pollution believed to affect the lives of some 100 million European citizens. The cost of the associated damage is estimated at more than ten billion euro per year. Noise leads to serious health problems, limits the capability to learn and effects the occupant comfort and performance in buildings. In this context, advanced noise abatement concepts are being developed in the demonstration project “Quiet Office” within the LOEWE-Center AdRIA (Adaptronics – Research, Innovation, Application), a large interdisciplinary research project funded by the German federal state of Hessia. As underlying principle for noise reduction concepts, Active Structural Acoustic Control (ASAC) is primarily being considered. Applying ASAC concepts, the noise radiation is controlled either by controlling the structural vibration of the radiating structure or by controlling the structure borne sound path. This paper will present the most recent concepts and results from the “Quiet Office”. Starting from more generic concepts, concepts specifically designed for office applications including smart windows will be discussed. Examples presented will include distributed absorbers, shunt technologies with piezoelectric ceramics, smart Helmholtz resonators and fully active noise and vibration control.
On site performances of ventilation windows
Authors: Wong H.K. , Yung C.N. , Tang S.K.
Published: April 2012

The present study investigates the performance, in term of sound attenuation, of ventilation windows when applied to a real situation. A full scale model consisted of two identical modular public housing residential flats was built up next to a very busy truck road with traffic noise level LA10 exceeding 80 dBA in general. One of these model flats was equipped with two ventilation windows, while the other with conventional windows having side-hung window panes. Noise measurements were carried out simultaneously inside both flats and at the façades of these model flats. The total conventional window opening size was kept at that of minimum prescribed area for ventilation (1/16 of floor area in Hong Kong). The measurements at the façades outside provided the necessary adjustments if necessary whereas the sound attenuation is the difference between the insertion loss of the ventilation window and the conventional window. The present results show that the current setup of the ventilation window can provide sound attenuation of 6.6 dB without any sound absorption treatment inside the window. The sound attenuation rose up to 8.1dBA when the two vertical interior sides and the interior top surface of each ventilation window were lined with such materials.
Influence of music performance on Sun Yat-sen Memorial Hall
Authors: Gu Linqiang , Lin Weixin
Published: April 2012

Currently, many heritage buildings have been converted into music performance venues. Performing at ultra high sound pressure has induced coupled vibration of building elements which should be of protected, then caused irreversible damage of them after a certain time, such that application requirements and cultural relic protection formed an inevitable contradiction. Research on a case study of Guangzhou's Sun Yat - sen Memorial Hall in China demonstrated that music performance has little impact on the structure safety but a passive influence on some heritage building elements like colored glass and some murals, gave a reference for selection and design of damping measures, and at the same time pointed out that some issues required further study in this area.
Research on experiments for high frequency sound propagation with rough surface in shallow water
Authors: An Xudong
Published: April 2012

A experiment was carried out to research high frequency underwater sound propagation with rough surface in shallow water. A wave-maker was used to simulate the sine wave surface with different wavelength, amplitude and cycle in a pool (108m×7m×3.5m). The multiple propagation tracks and the multiple reflections at surface and bottom as well as focusing and defocusing due to reflection from surface waves were measured and analyzed. The accuracy and efficient of experiment are verified by the agreement between the numerical simulation and the analysis results of the measured experimental data.
Effects of spatial attention on across-frequency grouping in speech
Authors: Cepeda Miguel , Best Virginia , Shinn-Cunningham Barbara
Published: April 2012

To understand speech, listeners integrate information across disparate frequency regions. Such integration may depend not only on low-level grouping cues (e.g., correlations in envelope across frequency) but also on volitional attention (e.g., integrating only frequency bands from a desired direction). Here, listeners reported the content of a target sentence conveyed by two spectrally separated, narrow bands of speech presented to the left ear. Two additional speech bands, centered between the other bands, were presented either to the left or the right ear. These additional bands were either from the target speech (matched) or an independent sentence (conflicting). In the key experimental block, listeners were instructed to attend to the speech on the left while either conflicting bands or, infrequently, matched bands were presented on the right. Splitting the target across the ears degraded intelligibility, showing that spatial separation interferes with grouping. However, directed spatial attention had no effect: intelligibility was equivalent when listeners explicitly were told to attend to the target bands split across both ears and equivalent trials in which listeners volitionally attended only the left ear. Results show that for structure-rich speech, directed attention does not overcome automatic grouping processes: across-frequency grouping of related speech bands is obligatory.
Functional subnetwork structure in auditory cortex for stream segregation
Authors: Noda Takahiro , Kanzaki Ryohei , Takahashi Hirokazu
Published: April 2012

Perceptual integration and segregation of alternating tone sequence differing in frequency (ABA-ABA-...) depend on the frequency differences (Delta-Fs) between A and B tones and the inter-tone intervals (ITIs) between successive tones. In the auditory cortex, tonotopic separation, forward suppression and multisecond habituation have been considered as possible neural correlates of this perceptual phenomenon. This model, however, cannot completely account for the van Noorden's perceptual boundary and the temporally continuous perception of auditory streaming. Here we examined the temporal changes of the functional network properties in auditory cortex to tone sequences with different Delta-Fs and ITIs. Specifically, we recorded local field potentials using microelectrode arrays from anesthetized and awake rats and constructed the functional network based on phase synchrony in gamma-band oscillation. As the results, the networks consisted of sub-networks highly correlated with tonotopy, and the sub-network selective to B tones lasted for a prolonged period at large Delta-F. Such characteristic substructures of functional network are a possible candidate of neural mechanisms of auditory stream segregation.
Effects of spatial localization on sentence recognition in noise
Authors: Nakagawa Tatsuo
Published: April 2012

Speech recognition in noise improves when speech and noise are separated in space. Interaural level and time difference cues are used in spatial localization. Most people with hearing loss have better hearing in the low frequencies. Interaural cues for sound localization are also more important in the low frequencies. An objective of the current experiment was to assess the effects of spatial separation of speech and noise on the recognition of low-pass filtered speech in persons with normal hearing and hearing loss. Speech levels corresponding to 50% correct recognition of sentences were measured in a 65dB SPL multi talker noise. Spatial benefits for listeners with and without hearing loss are discussed.
Effect of similarity between target speech and time-reversed masker on speech intelligibility
Authors: Jiang Bin , Yang Jun
Published: April 2012

The similarity between target speech and interfering signal may affect masking. Since time-reversed masker is an unintelligible speech-like signal, the influence of intelligibility can be avoided. This paper describes a sentence intelligibility test with target speech masked by different time-reversed maskers to evaluate the similarity effect. The time-reversed masker is processed by locally time-reversal segments of speech uttered by same-talker, same- and different-sex talker. The results show that the amount of masking is highly dependent on the similarity between target speech and time-reversed masker: time-reversed masker of target speech gives a rise in average speech reception threshold (SRT) of about 3 dB and 9 dB compared to that of another talker with same- and different-sex, respectively. Assuming the energetic masking effect for time-reversed maskers of different talkers to be similar, the amount of similarity with same-sex is larger than 6 dB and the amount of similarity with same-talker is larger than 9 dB.
Contribution of pitch-accent information to lexical decision in Japanese
Authors: Masuda-Katsuse Ikuyo
Published: April 2012

Word intelligibility, latency in shadowing, and brain activations when listening to spoken Japanese with incorrect pitch accents compared to normal, were investigated. Japanese is one of pitch-accent languages. In a pitch-accent language, “where” the pitch falls is important, whereas in Mandarin Chinese “how” pitch rises and falls is important. The word intelligibility scores were examined based on the adequacy rating of the accent types. Results reveal that under noisy conditions, the higher the adequacy of the accent type was rated, the higher the word intelligibility was. Under the clean condition, a significant negative correlation was shown between latency in shadowing and adequacy rating of accent types. In the event-related fMRI experiment, brain activities were investigated when listening to words with incorrect pitch accents (INCORRECT condition) and words with normal pitch accents (NORMAL condition). The contrast between INCORRECT and NORMAL revealed the significant activation in the bilateral inferior frontal, the bilateral precentral, and the left supplementary motor area, and right superior temporal gyrus. The result support the view that speech perception is a sensory-motor process, suggesting when a pitch accent of the stimulus was mismatch to the template, silent rehearsal might be repeated to make a lexical decision.
Auditory localization in realistic environments by normal-hearing and hearing-impaired listeners
Authors: Buchholz Jorg M. , Best Virginia , Keidser Gitte
Published: April 2012

The ability to correctly localize sounds is important for general awareness of the auditory scene and communication in adverse acoustic conditions. However, most localization studies are performed in rather simple and artificial conditions. In particular, very few studies have considered localization in reverberant environments or in the presence of complex interferers, and no studies have systematically investigated the effect of distance. In the present study, localization performance was therefore measured as a function of source-receiver distance using a virtual auditory environment. With increasing source-receiver distance the direct-to-reverberation energy ratio decreases and the auditory system increasingly relies on mechanisms related to the precedence effect. Both aspects may be particularly problematic for hearing-impaired listeners. The acoustics of a cafeteria was simulated with the room acoustic software ODEON for a large number of source-receiver locations. Signals were generated for a 3D array of 41 loudspeakers using the loudspeaker-based room auralization (LoRA) toolbox. Localization performance was measured in normal-hearing and hearing-impaired listeners with a bilateral hearing loss in the simulated cafeteria with and without a multi-talker speech background. The experimental results were correlated with a number of acoustic measures derived from dummy head recordings of the different acoustic conditions.
A modulation-transfer-function-based method for restoring sub-band power envelope from noisy reverberant speech
Authors: Morita Shota , Unoki Masashi , Lu Xugang , Liu Yang , Akagi Masato , Hoffmann Ruediger
Published: April 2012

The concept of the modulation transfer function (MTF) can be successfully applied to evaluating the quality of speech transmission in room acoustics (noisy reverberant environments) as functions of reverberation (reverberation time) and additive noise (signal to noise ratio) (Houtgast and Steeneken, J. Acoust. Soc. Am., 77, 1069-1077, 1985). This paper proposes a method of restoring the power envelope from noisy reverberant speech based on the MTF concept. The proposed method does not need the impulse response and noise conditions in room acoustics to be measured to enhance speech. The proposed approach suppresses the effects of reverberation and noise on the power envelopes by restoring the smeared MTF. We carried out massive simulations of noise-suppression and dereverberation on noisy reverberant speech to objectively evaluate the proposed method. The results revealed that the proposed method could simultaneously work well with both the suppression of noise and dereverberation. We further tested the proposed method as a front-end processor for ASR systems in noisy reverberant environments, and compared it with other methods (MFCC, CMN, spectral subtraction, and RASTA filtering on a constant-bandwidth filterbank). The results demonstrated that the improvement in recognition with the proposed method was more effective than that in extremely noisy reverberant environments.
High resolution data from DTAGS on the response of humpback whales to noise from seismic air guns
Authors: Dunlop Rebecca
Published: April 2012

The BRAHSS (Behavioural Response of Australian Humpback Whales to Seismic Surveys) series of experiments uses a multi-platform approach to determine the behavioural and acoustic response of humpbacks to noise from seismic air gun arrays. One of the data collection platforms utilises the DTAG, or acoustic digital recording tag. DTAGs are small suction cup tags which contain a hydrophone as well as x, y and z plane accelerometers, magnetometers and depth sensors. Data from the DTAGs allows fine scale movement data of the tagged whale (dive profile, pitch, roll and heading movements, fluking rates) to be viewed as a pseudotrack whilst simultaneously listening to sound field of the whale (air gun shots and vocal sounds from nearby whales). This paper presents some results of responses of the whales to air gun sounds recorded by DTAGs and comparison with visual observations at the time. Since DTAGs provide a continuous record of whale vocalizations and 3D movements, vocal and physical reactions are detectable immediately as the first air gun shot occurs, whereas visual observation are limited to the appearance of the whales at the surface.
Acoustic tagging for counting feeding events of captive Amazonian manatees
Authors: Kikuchi Mumi , Akamatsu Tomonari , A. de Souza Diogo , C. W. Rosas Fernando , M. F. da Silva Vera
Published: April 2012

The Amazonian manatee is one of four extant species in the mammalian order Sirenia. They are restricted to the freshwater rivers, lakes and floodplains of the Amazonian river basin where they eat floating and emergent aquatic plants. Visual observation of wild manatees is nearly impossible because of the turbid water and tiny exposure of nose at gentle respiration movement, which consequently precludes study of their underwater behaviour. In this study, we applied animal-worn sound recorder (AUSOMS-mini, System Intec Co., Tokyo, Japan) to two captive Amazonian manatees at INPA, Brazil, in order to record their mastication sounds. Five species of aquatic plants were offered to the manatees separately. Mastication-sounds were extracted by custom made software developed on Matlab for off-line analysis. The mastication intervals and temporal sound structure depended on species of plants. In addition, individual difference of mastication intervals observed in the two manatees was probably due to different body sizes. Overnight recording showed that both manatees kept feeding for more than 0.5 hours followed by 1.6 ± 1.3 hours interruption of feeding. Other sounds such as insect calls, rainfall, and vocalizations of other manatees could be useful to understand habitat selection, weather and presence of conspecifics. Acknowledgment Research and Development Program for New Bio-industry Initiatives
Using bioacoustic and satellite tags to study sperm whale depredation behavior, and to test new acoustic tracking methods
Authors: Mathias Delphine , Thode Aaron , Straley Jan , Calambokidis John , Schorr Gregory , Andrews Russel
Published: April 2012

Sperm whales have been depredating black cod from demersal longlines in the Gulf of Alaska for decades, but the behavior has now become pervasive enough that it is starting to affect government estimates of the sustainable catch, motivating further studies of this behavior. In 2007 and 2009, 11 bioacoustic “BProbe” tags were attached to adult sperm whales off Southeast Alaska under both natural and depredation foraging conditions. Measurements of the animal's dive profiles, acoustic behavior, and angular velocities allowed two categories of depredation to be identified. The dive depths and durations of “deep depredating” whales are similar to those of natural dives, but acoustic parameters show significantly significant differences. By contrast, “shallow depredating” whales conduct dives that are much shorter, shallower, and are four times more acoustically active than during natural foraging dives. In 2010, both a satellite and bioacoustic tag were deployed on a sperm whale near a two-element vertical tracking array. The location and acoustic data from the tags were used to confirm the long-range tracking ability of the fixed array system to ranges of at least 5 kms. [Work conducted under the SEASWAP program, supported by the 2011 North Pacific Research Board graduate student research award]
Photoacoustic microscopy of tissue lesions induced by high-intensity focused-ultrasound
Authors: Prost Amaury , Simandoux Olivier , Chassot Jean-Marie , Fort Emmanuel , Bossy Emmanuel
Published: April 2012

Photoacoustic imaging is a recent and rapidly developping technique that can provide images of optical absorption at depth in soft tissue. In this work, photoacoustic imaging is applied to detect tissue lesion induced by high-intensity focused-ultrasound (HIFU).Tissue changes during HIFU therapy include changes in optical tissue properties that may be detected using photoacoustics. However, although it has been demonstrated that HIFU lession could indeed be detected using photoacoustics (Chitnis et al., JBO 15(2), 2010, Cui et al., JBO 15(2), 2010), the exact origin of the observed contrast remains unclear. In this study, lesions induced in different types of biological tissue are imaged in vitro using a photoacoustic microscope. Lesions are induced in the tissue samples with therapeutic ultrasound in the MHz frequency range, and a photoacoustic microscope with imaging frequencies from the MHz to the tens of MHz range, are used to obtain acoustic-resolution photoacoustic images of lesions located at different depths in tissue. Several optical wavelengths, from 532 nm to the therapeutic window in the near-infrared are used to perform a spectroscopic study of the observed contrast.
Magnetoacoustic tomography with magnetic induction: a novel approach for electrical impedance imaging
Authors: Ma Qingyu , Zhang Feng , Sun Xiaodong , Chen Xuanze
Published: April 2012

As a novel image approach, magnetoacoustic tomography with magnetic induction (MAT-MI) was proved to posses the potential merits of enhanced contrast and high spatial resolution. In this paper, based on the theoretical analysis of pulsed magnetic excitation, eddy current induction, acoustic vibration, acoustic transmission and acoustic waveform collection, the principle of MAT-MI was deduced in formulae for cylindrical measurement configuration. It was proved that the collected acoustic waveforms comprise the information of conductivity distribution of the object in various vibration amplitudes and opposite phases. A tomographic algorithm for diffraction acoustic source was employed to perform image reconstruction for a two-layer cylindrical phantom model and the conductivity configuration in terms of shape and size was reconstructed. The theoretical theory was also testified by the experimental results for a tissue-like sample phantom that the collected waveforms had good agreements with the simulation predictions and reconstructed image provided the conductivity distribution of the model in both the configuration and the dimension. The favorable results of the research suggested a potential feasibility of MAT-MI in electrical impedance imaging.
Electromagnetic tomographic ultrasonic sensor
Authors: Grasland-Mongrain Pol , Mari Jean-Martial , Gilles Bruno , Chapelon Jean-Yves , Lafon Cyril
Published: April 2012

A tomographic method based on the Lorentz force for the measurement of the pressure of an ultrasound transducer is presented. When a metal wire is vibrating under the influence of a pressure field created by an ultrasound transducer while submitted to a magnetic field, the Lorentz force induces an electrical current. This current is considered proportional to the integral of pressure along the wire. By moving the wire perpendicular to the ultrasound axis, and rotating it around the same axis, a sinogram of the pressure field can be elaborated. Then an inverse Radon transform of the signal gives the pressure field spatial distribution. An experiment was conducted where a 1 MHz transducer generated an ultrasound wave with a focal point at 4 cm. A 100 μm in diameter shielded copper wire was placed perpendicular to the ultrasound propagation axis, and inside a 300 mT magnetic field created by a permanent magnet. The main advantages of the hydrophone created by the wire-magnet system are the large frequency bandwidth and the resistance to high pressure, parameters still under investigation. Possible disadvantages are the sensibility to electromagnetic noise and the possible distortion of the pressure field when using a too thick wire.
Systematic approach for wind noise analysis of buildings for engineering applications in Hong Kong
Authors: Ng C. W. , Lo K.W. , Tsoi Sam P.S.
Published: April 2012

Wind noise for tall buildings can be a concern for densely populated area. It is needed to develop a systematic approach of wind noise analysis for building design in engineering applications. This paper presents an innovative approach based on a three-tier analysis framework for wind noise assessment of external features in urban environment. The framework is divided into screening review of external locations susceptible of impact; broad assessment of areas susceptible to impact; and focused model assessment. In Tier 1, review of facade design is conducted to identify susceptible impacted areas. Screening criteria related to wind speed, shapes, dimension of facade elements are derived for evaluation of facade/architectural forms. Fundamental principles are applied to different turbulent flows to estimate relative significance based on Lighthill's Theory of aerodynamic noise. Statistical analysis of meteorological data is conducted from weather, wind tunnel/AVA study data to form representative wind conditions. In Tier 2, broad assessment of categorised areas is conducted by simplified calculations using scaling laws/ regeneration prediction technique to estimate wind noise significance. In Tier 3, focused assessment of potential areas is conducted for specific evaluations. CFD is applied to flow fields for computation of aero-acoustic characteristics of vortex sources using Lighthill-Curle equation.
Analysis on transmission of sound and vibration of underwater double cylindrical shells connected with noncontinuous slab ribs
Authors: Bai Zhenguo
Published: April 2012

To analyze the sound and vibration transmission characteristics of double finite cylindrical shells, modal superposition method is adopted to establish the analytical mode, in which interaction induced by water between shells and slab ribs connecting the shells is taken into account. The in-face and out-face motion of slab ribs bring forth the interaction of shells, and the former factor features in the vibration transmission of the double shells below the ring frequency of the shell. The circumferential discrete slab ribs is mathematically described as algebraic sum of some step functions, which is then expanded in sine function series to fit in with the control equation of double shells. The results show that: whether the slab ribs are discrete or continuous as an annular rib, the level of sound radiation of double shell doesn't alter a lot, instead of which, only the peak points move a bit. Keywords: Sound radiation, Step function, Double cylindrical shells
A case for using A-weighted equivalent energy as a damage risk criterion for impulse noise exposure
Authors: Murphy William J. , McKinley Richard L.
Published: April 2012

Damage risk criteria (DRCs) for continuous noise rely upon epidemiologic analyses of populations of persons exposed over several years to noise in occupational environments. In 2006, the U.S. Army proposed to update the MIL-STD 1474D to use the Auditory Hazard Assessment Algorithm for Humans (AHAAH) and discontinue using the peak sound pressure level, envelope duration and number of impulses. The National Institute for Occupational Safety and Health has conducted two separate evaluations of the data used to justify the AHAAH methodology and found that the use of the A-weighted equivalent energy LAeq8 was more suitable for the purposes of predicting the effects of temporary threshold shifts (TTS) both in humans and in chinchillas. The LAeq8 method provided best fit for the TTS outcomes and demonstrated the greatest discrimination (ability to predict TTS) when compared to AHAAH, MIL-STD 1474D and two other proposed DRCs. Similarly, LAeq8 was found to give the best-fit and greatest discrimination for the chinchilla impulse noise exposures. The LAeq8 affords the best sensitivity and specificity for discrimination of potential hazards and has the greatest level of integration with present occupational exposure standards and prospective hearing protection labeling regulations.