bluuebunny/crossref_metadata_2025 huggingface dataset:
Graduate education: Meeting the needs of the next generation of professionals in architectural acoustics
Authors: Xiang Ning , Braasch Jonas , Brooks Todd L. , Sykes David
Published: April 2012

In the fields of architectural-, physical- and psycho-acoustics the pace of change results from research, materials science and professional practice. Integrating the latest advances into pedagogy poses challenges for educators who are charged with training future experts and leaders, many of whom do not have technical backgrounds. To meet this need, the Graduate Program in Architectural Acoustics at the School of Architecture at Rensselaer Polytechnic Institute has re-shaped its pedagogy using “STEM” (science, technology, engineering and mathematics) methods enabling individuals from a broad range of fields to succeed in this rapidly changing field. RPI's curricula in architectural acoustics-leading to both M.S. and Ph.D. degrees -includes intensive, integrative hands-on experimental components that fuse theory and practice in a collaborative environment- a “STEM” method. The program has attracted graduate students from a variety of disciplines- including individuals with B.Arch., B.S., or B.A. degrees in Architecture, Music, Engineering, Audio/Recording Engineering, Physics, Mathematics, Computer Science, Acoustics, Electronic Media, Theater Technology and related fields. Following completion, most graduates pursue careers in acoustical consulting where an integrated understanding of complex, technical phenomenon is essential. RPI's curricula covers: Architectural Acoustics, Applied Psychoacoustics, Engineering Acoustics, Aural Architecture, and Sonics Research Laboratories.
Theoretical acoustics course for postgraduates in Naning University
Authors: Cheng Jian-chun
Published: April 2012

There is a one academic year theoretical acoustics course for postgraduate students in the Department of Acoustic Science and Engineering of Nanjing University. The course introduces the physical principles and mathematical methods for acoustics in fluids, and the main objective is to deepen understanding of acoustical principle for postgraduate students in the field of acoustics following their undergraduate fundamental acoustics course. The contents include acoustic waves in ideal fluids, acoustic radiation in infinite space, acoustic scattering and diffractions, propagation and radiation of acoustic waves in dust, acoustic fields in enclosed space, acoustic waves in dissipative fluids, acoustic waves in layered fluid, acoustic waves in moving fluids, propagation of acoustic waves with finite amplitude, and effects generated by acoustic waves with finite amplitude. More details can be found in the book title “Principle of Acoustics in Fluids” published by Science Press in China in 2012.
Numerical simulation of the transmission loss of plates
Authors: Piscoya Rafael , Burgschweiger Ralf , Ochmann Martin
Published: April 2012

Numerical simulations for estimating the transmission loss of plates can be an important alternative to measurements when there is no access to transmission loss test facilities. Furthermore, parametric studies and design changes can be made easily and faster. This work presents a method to calculate the transmission loss of plates placed between a source and a receiver room using an iterative approach. The sound radiation due to the vibration of the plates is solved with a Boundary Element formulation while the motion of the plate is determined using a Finite Element formulation with the sound pressure as the exciting force. The starting point is the blocked pressure approximation. The real pressure on the plate and its displacement are obtained after some iterations. If no damping in the plate is considered, poor or no convergence is expected at the resonant frequencies of the plate. This problem is avoided introducing some damping in the plate as well as in its fixation (boundary). With this approach, the use of existing techniques to accelerate the calculations that are already developed for the BEM, e.g. the Fast Multipole Method and for the FEM, e.g. the Model Order Reduction can be directly applied without needing to adapt them to this specific problem
Rapid bottom characterization using reverberation data
Authors: Wu Jinrong , Zhao Zhendong , Shang Erchang
Published: April 2012

Bottom characterization can be described by Geoacoustic model or bottom reflection model. In this work, simplified bottom reflection model in small grazing angle area was preferred. There are only two parameters P and Q in the model. P contains the phase shift information of bottom reflection. Q shows attenuation characteristics of bottom reflection. Spectrograms of reverberation data show evident coherent striations. The waveguide invariant, Beta, was extracted from these striations. For a Pekeris waveguide, a very simple analytic relation has been given: Beta = 1 + P/(k0Heff), here Heff is the `effective depth', and Heff = H + P/2k0. P can be deduced using this simple relation firstly. The new developed energy-flux model (with parameters P and Q) of waveguide reverberation based on Perturbation theory was used to inverse Q from the reverberation average intensity decaying line secondly. 2007 Qingdao reverberation experiment data was analysed to illustrate this rapid bottom characterization technique. The result shows that P and Q can be extracted from the reverberation data rapidly. [This work was supported by NSFC under Grant No. 10874201 and No. 11074271]
Short range sound propagation in shallow water and geo-acoustic parameters inversion
Authors: Zhang Xuegang , Meng Chunxia , Hu Haohao , Han Jing
Published: April 2012

The distribution of short range sound field is complicated in shallow water because layered structures of seabed and multiple reflection from surface have significantly effect on field, propagation model is established by using fast field program. Matched-field processing experiments are carried out respectively during two typical hydrographic seasons in north Yellow Sea. The seabed parameters are inverted based on Bayesian theory.The Results show that inverted parameters of two experimental data had a well consistency and multiple layered structure of seabed affected sound field at short range.
Music rehearsal room acoustics: comparisons of objectives and performance measures
Authors: Freiheit Ron
Published: April 2012

A comparison of the acoustic performance criteria for high school music education rehearsal rooms to standard classrooms in the United States and Asia. High school music rehearsal rooms have acoustical requirements that are very different from traditional classrooms, where academic subjects are typically taught in a lecture-based setting. Due to the extended frequency range and dynamics of music rehearsals, most standard classroom acoustic treatments will not provide effective results for music rehearsal rooms. A number of acoustic measurements will be discussed – comparing rehearsal rooms and standard classrooms. Potential problems and solutions will be identified.
Sound field diffusivity estimation using spherical microphone arrays
Authors: Jin Craig , Epain Nicolas
Published: April 2012

During the last decade, spherical microphone arrays have become increasingly popular in the acoustic community. These microphone arrays can be used for various applications such as beamforming, sound field reproduction and spatial sound field analysis. Within the context of sound field analysis and room acoustics, estimating the diffusivity of the sound field at a particular time instant is useful. In this paper we present an algorithm for evaluating the diffusivity of sound fields recorded by spherical microphone arrays. Results of numerical simulations show that this algorithm is more robust to the presence of sound sources in opposite directions to each other, as compared to previously proposed methods. In addition the algorithm provides an upper bound for the number of dominant sound sources.
A two-microphone method for localization of multiple speech sources using complex exponential transform of phase differences
Authors: Zhao Xiaoyan , Tang Jie , Zhou Lin , Wu Zhenyang
Published: April 2012

This paper proposes a two-microphone method for localization of multiple speech sources by utilizing speech's sparse attribute in time-frequency domain. The proposed method estimates time-delay of each source by applying complex exponential transform to the inter-channel phase differences (IPDs). In order to improve the performance in noisy environment, the proposed method selects time-frequency points with high SNR. The method obtains the initial time-delay estimate of each speech source by utilizing the IPDs at low frequencies, and then iteratively updates the time-delay by utilizing the whole selected points. With the complex exponential transform on IPDs, the proposed method takes full advantage of the high-frequency phase information, not requiring phase compensation for IPDs at high frequencies. Experiments have been conducted to study the effect of the exponential factor on the performance of the proposed method and to compare the performance of the proposed method with the generalized hard clustering algorithm. Experimental results show that the proposed method achieves an optimal performance when the exponential factor ranges between 0.8 and 1.2. Comparisons of the results show that the proposed method outperforms the GHCA algorithm under different noise and reverberation conditions, and the performance improvement increases as the SNR is decreased.
Evaluation of playback sounds by a newly developed dolphin-speaker
Authors: Mishima Yuka , Uchida Keiichi , Amakasu Kazuo , Miyamoto Yoshinori , Sasakura Toyoki
Published: April 2012

It is important to playback broadband sounds for the research of communication and echolocation of dolphins. Acoustic studies of dolphins mainly focus on recording of vocalizations and hearing abilities, but relatively few playback experiments have been conducted. To improve our understanding of their communication and echolocation abilities, an extremely broadband speaker, which is able to project communication sounds, whistles and burst-pulse sounds, and echolocation clicks, is anticipated. We developed a prototype Dolphin-speaker covering the frequency range from 30 kHz to 150 kHz within +/- 15 dB. Although the transmitting sensitivity of the prototype was almost flat at frequency band higher than 30 kHz, the sensitivity lower than 30 kHz was worse and it had some dips. Using two techniques, composition of the prototype and a Langevin-type element that has resonance at about 10 kHz and equalization for the ripples, the newly developed Dolphin-speaker has been improved having flat transmitting sensitivity from 5 kHz and 150 kHz within +/- 6 dB. A variety of sounds from captive dolphins were played back by the Dolphin-speaker. Visual and numerical comparisons of the playback sounds and originally generated sounds will be presented.
Discrimination of Diaphus theta and Euphausia pacifica using underwater irradiance
Authors: Tomohiko Matsuura , Kouichi Sawada , Kazuhisa Uchikawa
Published: April 2012

This study proposes scatterers discrimination method by using underwater irradiance in addition to the usual acoustic method. Mean volume backscattering strengths (MVBS) at 38 and 120 kHz and underwater irradiance were measured at fixed locations in the north-western Pacific from 24 to 27 August, 2008. Two sound scattering layers (SSLs) conducting diel vertical migration (DVM) at different depths were observed and were identified as Diaphus theta and Euphausia pacifica by net samplings, respectively. During DVM, both species followed mostly the constant light level. The mean irradiance at the lower and the upper outlines of SSLs for D. theta were ranged from -81.0 to -57.8 dB re μ mol/m2/nm and that for E. pacifica were ranged from -50.5 to -42.1 dB re μ mol/m2/nm, respectively. The mean and standard deviation of ▵ MVBS corresponding to the scattering layers of D. theta and E. pacifica were -4.7 ± 2.7 dB and 7.7 ± 3.2 dB, respectively. Scatterers discrimination using irradiance parameter in addition to usual ▵ MVBS parameter was found to be more effective to distinguish both species from other scatterers.
High frame rate velocity-coded speckle imaging platform for coherent blood flow visualization
Authors: Yu Alfred C. H. , Yiu Billy Y. S.
Published: April 2012

Non-invasive imaging of blood flow at over 100 fps (i.e. beyond video display range) is known to be of clinical interest given that such a high frame rate is essential for coherent visualization of complex hemodynamic events like flow turbulence. From a technical standpoint, getting into this frame rate range has became possible with the advent of broad-view ultrasound imaging paradigms that can track motion over an entire field-of-view using few pulse-echo firings. Leveraging on an imaging paradigm known as plane wave excitation, a novel high-frame-rate flow visualization technique has been developed to depict both blood speckle motion (using B-flow imaging principles) and flow velocities (using conventional color flow imaging principles). Experimental demonstration of this method has been carried out using a channel-domain research platform that supports real-time pre-beamformed data acquisition (SonixDAQ) and a high-throughput processing engine that is based upon graphical processing unit technology (developed in-house by the authors). In a case with a 417 fps frame rate (based on 5000 Hz pulse repetition frequency and slow-time ensemble size of 12), results show that high-frame-rate velocity-coded speckle imaging can more coherently trace fast-moving blood flow than conventional color flow imaging. Acknowledgement: Research Grants Council of Hong Kong (GRF 785811M)
Pulse compression in time-varying systems with applications in ultrasonic vibrometry and tissue elastography
Authors: Martin James , Rogers Peter , Gray Michael
Published: April 2012

Pulse compression is normally applied only to time invariant systems, as the variation of a system's properties during its interrogation violates assumptions of the compression process. However, there is an exact solution to the pulse-compression problem when the time variance satisfies specified criteria. These are the same criteria that are required for the operation of an ultrasonic vibrometer in the context of a tissue elastography system. They are the requirement that the variations be very small in comparison with the wavelength of the interrogating ultrasound signal and that they be within a single Nyquist band as sampled at the periodicity of that signal. The solution to this problem involves a step-wise interpolation of the static pulse-compression transfer function in the frequency domain. It is possible to show that this technique offers significant advantages in terms of measurement time and/or measurement resolution when the limiting source of noise is any other than ambient ultrasonic noise or thermal noise at the receiving transducer, because the acoustic energy in the region of interest is limited by regulatory standards for diagnostic ultrasound. The technique has been demonstrated both analytically and with numerical models. It has also been tested in laboratory experiments on tissue phantoms.
Dynamic effective medium theory for periodic structures with application to acoustic cloaking metamaterials
Authors: Norris Andrew
Published: April 2012

Expressions are presented for the fully dynamic effective material parameters governing the spatially averaged fields in three dimensional periodic systems. The results, which are valid at any frequency and wavenumber, are obtained by using the plane wave expansion (PWE) method. The effective equations are of Willis form with coupling between momentum and stress. Applications to layered fluids are first illustrated, showing that the effective density must be anisotropic and frequency dependent. A metamaterial proposed for cloaking - Metal Water - will be considered in detail as a function of frequency.
Effective dynamic constitutive parameters of acoustic metamaterials with random microstructure
Authors: Caleap Mihai , Drinkwater Bruce W. , Wilcox Paul D.
Published: April 2012

A multiple scattering analysis in a non-viscous fluid is developped in order to predict the effective constitutive parameters of certain suspensions of disordered particles or bubbles. The analysis is based on an effective field approach, and employs suitable pair-correlation functions in order to account for the essential feautures of densely distributed particles. The effective medium that is equivalent to the original suspension of particles is a medium with space and time dispersion, and hence, its parameters are functions of the frequency of the incident acoustic wave. Under the quasi-crystalline approximation, novel expressions are presented for the effective constitutive parameters, which are valid at any frequency and wavelength. The emerging possibility of designing fluid-particle mixtures to form acoustic metamaterials is discussed. Our theory provides a convenient tool to test ideas in silico in search for new metamaterials with specific desired properties. An important conclusion of the proposed approach is that negative constitutive parameters can also be achieved by using suspensions of particles with random microstructures with properties similar to those shown in periodic arrays of microstructures.
Seismic wave attenuator made of acoustic metamaterials
Authors: Kim Sang-Hoon
Published: April 2012

We suggest a new method of an earthquake-resistant design to support conventional aseismic designs using acoustic metamaterials. Our device is an attenuator of a seismic wave. Constructing a spherical shell-type surface waveguide that creates a stop-band for the seismic wave, we convert the wave into an evanescent wave for some frequency range without touching the building we want to protect. It is a simple and practical method to reduce the amplitude of a seismic wave exponentially. Controlling the width and refractive index of the waveguide, we can upgrade the aseismic range of the building as needed in order to defend it. It may applicable for social overhead capitals such as power plants, dams, airports, nuclear reactors, oil refining complexes, long-span bridges, express rail-roads, etc.
Updating the WHO guidelines on community noise
Authors: Kim Rokho
Published: April 2012

Adverse health effects of community noise are a growing concern in many countries. To provide evidence-based policy guidance to the member states, the World Health Organization published Guidelines for Community Noise (1999), Night Noise Guidelines for Europe (2009), and Burden of Disease from Environmental Noise (2011). The Parma Declaration on Environment and Health (2010) urged WHO to develop guidelines on noise suitable to reduce children's exposure to noise, including that from personal electronic devices, recreation and traffic, especially in residential areas, at child care centres, kindergartens, schools and public recreational settings. Accordingly, the Noise Guideline Development Group (NGDG) was convened for renewing the WHO guidelines on community noise. The new guidelines, to be finalized by 2013, will reflect newly available evidence on adverse health effects of community noise from various sources. Newly emerged issues such as windmill noise and neighbourhood noise will be addressed. The whole process from formulation of the topics and choice of the relevant outcomes, evidence retrieval, assessment and synthesis through systematic review, to formulation of the recommendations will follow the standard WHO guidelines for guidelines development to eliminate any potential conflict of interests by ensuring the highest level of transparency and accountability.
Environmental noise management and sustainable urbanization
Authors: Schwela Dietrich
Published: April 2012

Each day 180,000 people are moving into urban areas. As a society develops, it increases its level of urbanization and industrialization and the extent of its transportation system. Each of these developments brings an increase in noise load. A major contribution to noise exposure comes from the sound emissions of vehicles, which are commuting over large distances every workday. There is a direct relationship between the level of development in a country and the level of noise impacting on its people. Without appropriate intervention, the noise impact on communities will escalate. Sustainable urbanization means the application of the concept of sustainable development to the field of urban planning. Six basic principles are being applied in order to achieve sustainable urbanization: Compactness, completeness, conservation, comfort, co-ordination and collaboration. However, sustainable urbanization is more than the application of these basic principles. It has also to do with resource limits, avoidance of their exhaustion and mitigation of environmental pollution. Environmental noise management can contribute to achieve these goals. In this paper the linkage between environmental noise management and sustainable urbanization is elaborated. The paper develops a framework on how environmental noise management can contribute to sustainable urbanization.
Future environmental noise and health research needs for policy
Authors: Stansfeld Stephen , Clark Charlotte
Published: April 2012

There is increasing evidence of the effects of environmental noise on human health with studies linking noise exposure to higher risk of hypertension, stroke and even mortality. However, there are gaps in the evidence and a lack of robust exposure-response relationships. There is also debate about whether much of the health effects of road traffic are attributable to noise or air pollution. There is a need for research that quantifies the effect of noise on health and assesses the total burden of disease attributable to environmental noise. Recommendations are reported based on the findings of the European Network on Noise and Health, funded by the EU 7th Framework Programme, to show how this could be achieved.
Relating the harmonic-rich sound of the Chinese flute (dizi) to the cubic nonlinearity of its membrane
Authors: Tsai Chen-Gia
Published: April 2012

Among the flute-type instruments all over the world, only the Chinese flute (dizi) and the Korean taegum have a membrane covering a hole in the wall of the instrument between the embouchure hole and the uppermost finger-hole. Nonlinear vibration of the dizi membrane endows dizi tones with a bright quality, which is due to the harmonics in the frequency range of 4–7 kHz. We provided a Duffing model of the dizi membrane, finding good agreement between this model and experimental results. Furthermore, we suggest that wrinkling of the membrane may be critical to its cubic nonlinearity.
Changes in acoustical design from ancient shakuhachi to modern shakuhachi
Authors: Yoshikawa Shigeru
Published: April 2012

The shakuhachi was originally introduced from China in the Tang dynasty around 750. Since this ancient shakuhachi has been preserved in the Shousouin of the Toudaiji temple, it is called the “Shousouin shakuhachi”. This shakuhachi, which has six tone holes to play a Chinese diatonic scale (e.g., A-B-Db-D-E-Gb-A, D-E-Gb-G-A-B-D), was adapted to play a Japanese pentatonic scale (D-E-G-A-B-D) by removing the second tone hole (Gb) around early 16th century. Moreover, the positions of five tone holes were modified to make effective use of the pitch bending (e.g., Eb) by drawing down player's jaw and half-covering the tone hole(s) around the 17th century, and a scale pattern D-F-G-A-C-D was established. Since this shakuhachi (made from the root end of bamboo) was played exclusively by a group of wondering priests (“Komusou”), it is called the “Komusou shakuhachi” and regarded as the origin of the modern shakuhachi. Changes in acoustical design from the Sousouin shakuhachi to the Komusou shakuhachi are considered based on the input admittance calculated from the inner geometry. The blowing conditions of the Shousouin shakuhachi are estimated from the investigation carried out during 1948 to 1952. Some problematic points in cross-fingerings of the Shousouin shakuhachi are also discussed.
Facts and ideas for the development of an integrated sound and health effects research in a globalized world
Authors: Lercher Peter
Published: April 2012

The environmental health effects research in environmental acoustics often reveals substantial differences in the obtained results which consequently lead to different conclusions and implementations in administration and policy. This paper intends to discuss some of the possible reasons underlying these discrepant results from a socio-cultural and social medicine viewpoint. For this purpose three complementary approaches are outlined and respective examples are presented. First, a sound source related perspective is investigated to explain potential differences in health outcomes. Second, a context related perspective is used to show empirical evidence for the variety of the contextual frameworks possibly responsible for observed differences in outcomes or importance of moderating factors. Eventually, with a health outcome related perspective possible differences in the underlying morbidity structure and health concepts are explored as potential sources for discrepant results.
A western perspective on research in underwater acoustics and acoustical oceanography
Authors: Buckingham Michael J.
Published: April 2012

Underwater acoustics and acoustical oceanography are both concerned with sound underwater, the distinction between them being that the former deals primarily with forward problems such as acoustic propagation and scattering, whereas the latter involves the inversion of sound fields to obtain information about the oceanographic environment. Over recent years in the USA and Europe, both disciplines have tended to move away from the use of dedicated acoustic sources, over concern about damage that such sources may inflict on marine mammals. Ambient noise has, to some extent, replaced dedicated sources as the sound field of choice, since it offers the prospect of returning a wealth of information about ocean processes but without the threat to the marine mammal population. To extract such information, the properties of the noise field itself must be well understood (underwater acoustics), as must the inversion procedures necessary to recover the information contained in the noise (acoustical oceanography). A brief introduction to the properties of ambient noise fields will be followed by several examples of noise inversions, the latter illustrating not only the utility of ambient noise inversions but also the complexity of typical noise fields in the ocean. (Research supported by the Office of Naval Research).
Comparison of transfer functions between the actual pinna and the simple pinna model which is composed of a rectangular plate and three rectangular cavities
Authors: Ishii Yohji , Takemoto Hironori , Iida Kazuhiro
Published: April 2012

A simple pinna model which is composed of a rectangular plate with three rectangular cavities (three-step model) has been proposed (Takemoto et al., 2010). The results of numerical simulations using FDTD method showed that the three-step model generates typical peak-notch pattern of HRTFs. However, it is not clear whether transfer functions similar to the subject's HRTFs are generated by the three-step model when the size of each part of the model is adjusted to that of the subject's pinna. Since the 1st and 2nd notches (N1, N2) and the 1st peak (P1) in HRTFs are known as the spectral cues for the front-back and the vertical localization (Iida et al., 2007), it is important that the frequencies of these notches of the pinna model agree to those of the actual HRTFs. In the present study, various three-step models whose sizes are adjusted to those of the subject's pinna are created, and the transfer functions are measured. The results show that the frequencies of N1, N2, and P1 for several models are almost same as those of the subject's HRTFs. A part of this work is supported in part by Grant-in-Aid for Scientific Research (A) 22241040.
Analysis on the stability of spatial interpolation schemes for head-related transfer function
Authors: Liu Yang , Xie Bosun
Published: April 2012

Head-related transfer functions (HRTFs) are transfer functions from sound source to two ears. They vary as continual functions of source direction. Usually, measurement yields the HRTFs at discrete directions, and HRTFs at unmeasured directions should be estimated by spatial interpolation. There are several familiar interpolation schemes, such as adjacent linear interpolation, the global interpolation, bilinear interpolation and spherical-triangular interpolation. In practice, potential subject's head movement in HRTF measurement may result in error in measured HRTFs, which may in turn deteriorate the interpolation performance. In present work, the performances for interpolation schemes against the error caused by slight head movement in HRTF measurement are evaluated and compared. The results indicate that overall, global interpolation scheme is superior to others in terms of signal-to-distortion ratio in interpolated HRTFs when undergoing a slight head movement in HRTF measurement. Taking advantage of the analog relationship between HRTF spatial interpolation and signal panning or mixing methods for multi-channel sound, the present analysis can also be extended for evaluating the signal panning methods for multi-channel sound.
The evaluation of pipe corrosion through the use of ultrasonic guided wave and novel matching pursuit
Authors: Tse Peter W. , Wang Xiaojuan
Published: April 2012

Ultrasonic guided wave is in routine use of the nondestructive testing fields as an advanced technique. However, in guided wave based pipeline inspection, the accurate evaluation of the severity of defect is always a challenging task. That is, although the reflection signal in principle includes substantial defect information related to severity and other features of the defect, it is usually rather difficult to be interpreted because of the complexities of reflection process. To carry out the planned maintenance on defective pipelines accurately and efficiently, the ability of evaluating defect severity for pipeline inspection is very important in practical application of guided waves technique, particularly for the cases in which defects exist in the parts of pipeline where their accesses are difficult. In this paper, we propose a method based on matching pursuit for quantifying the severity of pipeline defect along axial direction. The optimized dictionary through introducing prior-knowledge about reflection components is constructed for interactive process of matching pursuit to efficiently decompose the required edge reflection components from defect reflection signal. The axial extent of defect can be then quantitatively evaluated by using obtained information. The experimental results are used to demonstrate the effectiveness of the proposed method.
Numerical analysis comparison of joint matrix and transfer matrix approach for acoustic transmission of composite elastic plate
Authors: Huang J. H. , Tsai Yu-Ting
Published: April 2012

This paper investigates the phenomenon of sound transmission loss of the muti-layer composite elastic plate which includes the different thickness and material in each isotropic laminate. Unlike the classic plate concept, this paper considers that the sound waves in a fluid medium are converted into elastic waves in the plate and then converted back into sound to the fluid medium on the other side. According to thick plate theory, the two numerical methods are proposed to solve the muti-layer dynamic stiffness matrix by using transfer matrix approach and joint matrix approach. Two experiments are explored in this paper, one is to change the number of laminate of composite plate to compare the computational efficiency and differences for both numerical analysis; the other is by changing the material properties of each laminate of composite plate to explore the lossless level of sound transmission, sound reflection and sound absorption of different composite elastic plate. Through the result and discussion, this paper provides the useful acoustic transmission assessment concept of sound absorption sandwich panel for designing the mechanical noise/vibration suppression and architectural acoustics isolation.
Does a stop bias exist in infant consonant manner-of-articulation perception?
Authors: Nam Young-Ja
Published: April 2012

Phoneme inventories are biased favoring stop over fricative consonants. A similar bias is evident in acquisition. For example, an asymmetrical pattern was observed when infant word learning was assessed using the switch task with stop-initial and fricative-initial minimal pair CVC nonsense syllables (Altvater-Mackensen & Fikkert, 2010). In this task, Dutch-learning fourteen-month-olds noticed a fricative to stop change but failed to detect a stop to fricative change. These findings were interpreted in terms of phonological representations emerging in early lexical development. In this study, we tested English and French infants aged 4-5 months to determine whether they show a perceptual bias favoring stop manner. We presented CVC nonsense syllables - /bas/ and /vas/- in a preference task using the look-to-listen procedure. The /b-v/ contrast is phonemic in English and French. Infants listened significantly longer to /bas/ than to /vas/ trials (p = .004). This perceptual preference cannot be explained in terms of phonological representations in young infants who are not yet producing stops or fricatives and have almost no receptive vocabulary. We will discuss this phonetic bias in light of adult data showing similar perceptual asymmetries and consider the implications for the development of infant speech processing and early word learning.
Stimulus-dependent modulation of vocalization-induced cortical activation
Authors: Chen Zhaocong , Liu Peng , Li Weifeng , Lin Qiang , Liu Hanjun
Published: April 2012

It has been well documented that sensory responses to self-produced speech/vocalization are suppressed when compared to the sounds that are produced externally. Some recent studies, however, reported enhancement effect for active vocalization relative to passive listening. The present study was to address whether speaking-induced cortical activation can be modulated by the physical features of the stimulus. Subjects sustained a vowel phonation and heard either their pitch-shifted voice (100 cents, or 500 cents) or a sum of their vocalization and pure tone or white noise during mid-utterance. During passive listening, subjects remained silent and listened to the playback of what they heard during active vocalization. Compared with passive listening, the results showed enhanced P2 responses for 100 cents condition whereas suppression effect for tone or noise condition. 500 cents condition elicited nothing but suppressed effect for N1 response. These findings suggest a stimulus-dependent modulation of vocalization-induced cortical activation, leading to enhancement or suppression effect relative to the play back of the vocalization. The results are discussed in relation to differential mechanisms underlying online mornitoring of auditory feedback at utterance onset and during mid-utternance.
Cue-trading of tonal perception in Hai'an Mandarin
Authors: Ji Sunjing
Published: April 2012

It has been known that the perception of a phonological category is sensitive to cue trading among multiple phonetic parameters (Liberman, 1996; Francis et. al., 2008; Holt and Lotto, 2006). Following Abramson and Erickson (1992), this paper further explores the question of whether the perception of tonal categories in a Chinese dialect, Hai'an Mandarin, is sensitive to the trade-off between the VOT (voice onset time) of the onset of a mono-syllabic word and fundamental frequencies (F0) of the rhyme of the word. The interactions between VOT and F0 for the bootstrapping of the tonal categories are discussed in the context of several perceptual experiments. It is suggested that such psychological basis of tone perception is in tune with one tonogenesis theory, which says that tonal contrasts are generated as compensation for the loss of voicing distinction of the onset consonants (Hombert et al., 1979).
The communicative influence of gesture and action during speech comprehension: gestures have the upper hand
Authors: Kelly Spencer , Healey Meghan , Ozyurek Asli , Holler Judith
Published: April 2012

Hand gestures combine with speech to form a single integrated system of meaning during language comprehension (Kelly et al., 2010). However, it is unknown whether gesture is uniquely integrated with speech or is processed like any other manual action. Thirty-one participants watched videos presenting speech with gestures or manual actions on objects. The relationship between the speech and gesture/action was either complementary (e.g., “He found the answer,” while producing a calculating gesture vs. actually using a calculator) or incongruent (e.g., the same sentence paired with the incongruent gesture/action of stirring with a spoon). Participants watched the video (prime) and then responded to a written word (target) that was or was not spoken in the video prime (e.g., “found” or “cut”). ERPs were taken to the primes (time-locked to the spoken verb, e.g., “found”) and the written targets. For primes, there was a larger frontal N400 (semantic processing) to incongruent vs. congruent items for the gesture, but not action, condition. For targets, the P2 (phonemic processing) was smaller for target words following congruent vs. incongruent gesture, but not action, primes. These findings suggest that hand gestures are integrated with speech in a privileged fashion compared to manual actions on objects.
Correction errors in sound barrier measurement caused by temperature and wind variance
Authors: Wang Xun , Vorlaender Michael
Published: April 2012

The impulse response and its associated transfer function are the most important properties of linear and time invariant acoustic systems. Under low signal-to-noise conditions, e.g. measuring the sound barrier outdoors, the time-frequency windowing can be performed to reduce the noise at the time-frequency blocks where the noise does not overlap with the excitation signal, and at the blocks where the noise overlap with the excitation signal, the averaging methods have to be implemented. However, the averaging methods have to be performed in time-invariant systems, and in time-variant systems, averaging methods may lead to unpredictable errors. In sound barrier measurement, the time variance usually results from the temperature shift and the wind action. As for the temperature shift, the impulse response varies with a time-stretching process. And the wind action causes the phase and magnitude shift of the impulse response. Both the time-stretching factor and phase-shifting factor can be estimated by maximizing the cross correlation function between the measured impulse responses. Finally, the averaging can be performed after modifying the temperature- and wind-dependent impulse responses to constant-temperature and non-wind impulse responses. In this presentation, the stability of this time-stretching and phase-shifting average method will also be discussed.
High frequency ocean acoustic tomography observation at coastal estuary areas
Authors: Zhang Yu , Zhao Zongxi , Chen Dongsheng , Yang Wuyi
Published: April 2012

Ocean acoustic tomography (OAT) technique can obtain oceanographic information and has been received a lot of interest. High frequency OAT (in few kHz range) can be used for small and confined areas such as estuaries and bays with complicated hydrological conditions. In this study, we investigate the application of the high-frequency reciprocal transmission OAT to assess the temperature and current in Xiamen sea area using computer simulations and sea experiments. Based on the temperature data obtained from remote sensing, high frequency OAT is employed to reconstruct two-dimensional temperature, sound speed, and current field of the 1.2 km × 1.2 km region. The results show that increasing the number of acoustic stations decreases the travel-time errors of high frequency OAT; however, excessively increasing stations can not significantly improve the inversion accuracy. Furthermore, this method has also been examined by a sea experiment on monitoring the current and water temperature of Wuyuan Bay. High frequency OAT might provide an effective method on temperature and current observation at coastal estuary areas. (This work was financially supported by the National Science Foundation of China (Grant No. 11174240) and the Fundamental Research Funds for the Central Universities (2011121010))
Study of ocean ambient noise characteristics based on vector signal processing of acoustic energy flow
Authors: Li Jialiang , Lin Jianheng , Yi Xuejuan
Published: April 2012

With the development of technology, vector sensors are more and more applied in underwater acoustics measurements. As one of the signal processing methods, vector signal processing method based on acoustic energy flow is gradually developed. Methods based on acoustic energy flow overcome some inherent shortcomings of traditional pressure signal processing methods and increase processing gain and DOA estimation accuracy. Methods based on acoustic energy flow have been verified to be practically useful by trials. The existing vector sensor frequency measurement model is modified in this paper. The anisotropy and other characteristics of ocean ambient noise are studied in the paper based on vector signal processing of acoustic energy flow, and the simulation results are reasonable.
Estimation and analysis of the underwater construction noise of the offshore wind farm in the west coast of Taiwan
Authors: Tsai Henry H. J. , Lin Sheng Fong , Chen Chi-Fang , Wu Jeff C. H.
Published: April 2012

Wind-generated electricity has been one of the green energy in the world. In Taiwan, there is enormous potential for wind energy, especially in the west coast. However, there are many marine mammals in this area, so we cannot neglect the environmental problem due to the construction noise of the offshore wind farm. This research is to estimate and analyze the underwater construction noise of the wind farm. According to the data of hydrographic, bathymetric and sediment, the spreading and impact range of the construction noise arising from the offshore wind farm can be estimated and simulated. The result of this study may be taken as a reference of the construction of the offshore wind farm.
Acoustic mode coupling resulting from an internal solitary wave approaching a shelf break in South China Sea
Authors: Chiu Linus Y. S. , Chang Yuan-Ying , Chen Chi-Fang , Reeder D. Benjamin , Chiu Ching-Sang , Lin Ying-Tsong , Lynch James F.
Published: April 2012

An internal solitary wave (ISW) encountering the shelf break, making the waveguide is compressed, can cause different joint coupling effect for acoustic modes. In this paper, the extended criterion for adiabatic invariance is developed by parameterizing the joint mode coupling effect of an ISW encountering the shelf break and is used for sensitivity studies considering various internal wave amplitudes and slope angles of shelf break, to examine the acoustic coupling effect resulting from both bathymetry and ISW. The modeling results are accurately predicted by the extended criterion of adiabatic invariance and compared to experimental observations from ASIAEX and NLIWI of the effect of acoustic waveguide being compressed by the shelf break and ISW. Results demonstrate that the coupling of acoustic energy to higher modes as the waveguide is compressed when the ISW encounters the shelf break. And as amplitude of the ISW and the incline of the sloping bottom increase, coupling strength for both adjacent- and non-adjacent modes is enhanced. [This research is sponsored by national science council.]
Making speech announcements intelligible in public spaces from a speech production view
Authors: Hodoshima Nao , Arai Takayuki
Published: April 2012

Speech announcements in public spaces are often hard to hear due to noise and reverberation, and this is especially true for elderly people compared to young people. This study aims to improve speech intelligibility in noisy/reverberant environments based on the way we change how we speak depending on an acoustic environment. Speech uttered in a noisy environment (noise-induced speech) is generally more intelligible for young people than speech produced in a quiet environment when both types of speech sounds are heard in noise (i.e. Lombard effect). This paper examines whether reverberation- as well as noise-induced speech are more intelligible to young and elderly people. The results of our listening tests showed that elderly listeners had significantly higher word identification scores for noise/reverberation-induced speech than speech spoken in a quiet environment. The results also showed that noise/reverberation-induced speech was more intelligible to the listeners than speech in quiet with background noise/reverberation conditions that were not only identical but also different to those used during the recording of speech. The results suggest that using noise/reverberation-induced speech for public address systems makes speech announcements more intelligible for elderly people in public spaces. [Work supported by KAKENHI (21700203) and Sophia University Open Research Center.]
Subharmonic scattering of phospholipid-shell microbubbles as a function of hydrostatic pressure
Authors: Frinking Peter , Gaud Emmanuel , Casqueiro Gilles , Arditi Marcel
Published: April 2012

Subharmonic scattering of phospholipid-shell microbubbles excited at very low acoustic pressure amplitudes has been associated with echo responses from compression-only bubbles. These bubbles are near a tension-free buckling state at rest and have initial surface tension values close to zero. In this work, subharmonic scattering of phospholipid microbubbles was investigated as a function of the initial surface tension, which was controlled by changing the hydrostatic pressure through the application of an ambient overpressure. Echo responses from a dilution of an experimental contrast agent were measured as a function of ambient overpressure ranging between 0 to 140 mmHg. The microbubbles were excited using a 64-cycle Tukey-windowed transmit burst with a center frequency of 4 MHz and peak-negative pressure of 50 kPa. Echo-power spectra were calculated, and the subharmonic response was determined for each overpressure value; the subharmonic amplitude increased by 20 dB after applying 140 mmHg overpressure (for which the initial surface tension was assumed to be near zero). In this study, an increase in subharmonic amplitude, instead of a decrease as reported by others [Shi et al., UMB 1999], was measured as a function of ambient overpressure. This observation may be exploited in a new method for noninvasive pressure measurement.