bluuebunny/crossref_metadata_2025 huggingface dataset:
Empirical AM-FM decomposition of auditory signals
Authors: Meng Qinglin , Yuan Meng , Zhao Jianping , Feng Haihong
Published: April 2012

Cochlea, known as `fourier analyzer' in auditory system of mammals, codes the mechanical wave to electrical signals tonotopically. Meanwhile, the auditory coder also works in temporal mode, where envelope (E, i.e. amplitude modulation (AM)) and temporal fine structure (TFS, i.e. frequency modulation (FM)) are both significant but not exactly defined. In several recent researches (e.g. [Smith, et. al, 2002]), hilbert transform (HT) was utilized to extract the E and TFS cues. Though HT is mathematically rigorous, it is lack of clear physical meaning on AM-FM. This research introduces the empirical mode decomposition (EMD) to auditory research field. EMD was designed for analysis of non-linear and non-stationary data including natural sound. It is observed that the outputs of a auditory filter (e.g. Gammachirp), which was born as narrow-band filters, are approximately intrinsic mode functions (IMF) that admit well-behaved hilbert transforms (implying having physical significance). However, non-narrow-band filter (NNBF) output can be decomposed into two obvious IMFs or more, implying that HT is not suited to NNBF. EMD with HT provides auditory researchers one more perspective on AM-FM decomposition of auditory signals.# This work is supported by National Natural Science Foundation of China (11104316) and Shanghai Natural Science Foundation (11ZR1446000).
New evidence for audiovisual speech scene analysis: Low level interaction between auditory streaming and visual cues in speech perception
Authors: Berthommier Frédéric , Schwartz Jean-Luc
Published: April 2012

We have proposed in the last years that there could exist a level of audiovisual binding (audiovisual speech scene analysis) previously to audiovisual fusion and speech comprehension. In this paper, we propose a new paradigm in which a competition exists between a non-speech auditory stream and an audiovisual speech stream for incorporating the pre-voicing component (PVC) excised from a /b/. The auditory stream is composed of low intensity PVCs at a regular rhythm of about 1Hz, interleaved with /pa/ syllables at about 0.3Hz, forming the speech stream. The listeners' tasks is an online forced choice between /p/ and /b/, which relies on the level of capture of a PVC within the speech stream (hence perceived as /b/) or within the auditory stream (speech being hence perceived as /pa/). The regular PVC stream has the tendency to capture the common PVC. Surprisingly, the vision of lips movements enhances this capture effect, and the phonetic fusion between the common PVC and the /p/ is disfavored. To characterize this effect, two supplementary experiments have been carried out, suggesting this effect is (at least partly) speech specific. This supports our proposal for an audiovisual speech binding mechanism.
Extrinsic context is crucial for talker normalization in Cantonese tone perception
Authors: Zhang Caicai , Peng Gang , Wang William S-Y.
Published: April 2012

Previous studies showed that recognizing a phonetic category produced by different talkers relies on both intrinsic (target-internal) and extrinsic (contextual) cues. Extrinsic cues influence perception when intrinsic cues allow more than one phonetic interpretation. A recent study in this laboratory found that the configuration of tone systems (Cantonese and Mandarin) affects the degree of ambiguity of tones associated with intrinsic cues. In Cantonese which has three level tones, an isolated level pitch can be mapped to any of these three categories. Cantonese but not Mandarin listeners were found to confuse tones in a way biased by relative pitch height of different talkers. The present study tested Cantonese listeners on stimuli from four talkers with different pitch ranges (Female High, Female Low, Male High, and Male Low). Syllable /i/ carrying different F0 contours was embedded in a meaningful sentence with cues of a talker's F0 range. This study found enhanced identification accuracy with contextual cues over performance in isolation (92.25% vs. 51.75%), suggesting that extrinsic context facilitates talker normalization. This finding implies that extrinsic cues are especially useful for a language with intrinsically ambiguous phonetic categories. [Research supported by GRF 455911, NSFC 11074267, NSFC 61135003, and a 973 grant 2012CB720700.]
Tone duration and tonal slope of a cochlear implant child in comparison with a normal hearing child: A longitudinal study of a pair of twins
Authors: Chen Li-mei , Chen Ya-Wen , Chou Yi-Ru
Published: April 2012

The aim of this study is to observe the tonal acquisition in a pair of fraternal twins from 1 to 3 years old, making a comparison between a child with cochlear implant (Child A) and a child with normal hearing (Child B). Spontaneous data were transcribed and later tone duration and tonal slope were measured by Praat. Four main tones in Mandarin were analyzed: high-level, high-rising, high-falling, and low-falling tones. Major findings are: 1) Tone duration of Child B is longer than that of Child A by 1.2-1.7 times. The average of tone duration in Child A is 250ms-260ms; 2) In Child A, high-level tones show the shortest duration among the four main tones, and high-rising tones are the longest; 3)Tonal slope of Child A is flatter than in Child B. The absolute value of tonal slope is higher in Child B; 4) Children control high-level tone the best, followed by high-rising, then high-falling, and low-falling the last.
Visual displays of the pitch pattern for the CAI self-teaching system to discriminate Chinese tones
Authors: Sun Qi , Liu Song , Sunaoka Kazuko , Hiki Shizuo
Published: April 2012

A computer-assisted instruction (CAI) system for self-teaching to discriminate Chinese tones is available for public through the internet (http://chinesetone.org) in Japanese, English, and Chinese versions. The design and construction of this system has been reported previously (Hiki et al., J. Acoust. Soc. Am., 120 (5, Pt. 2), 2006, 3168). This system utilizes the displays of the pitch pattern as visual cues in training. The following new functions of the visual displays have been added to the system recently: 1) Essential pitch patterns of 15 bisyllabic words, with every combination of the four tones in Standard Chinese, were drawn on the six whole tone musical scale. By displaying visually the corresponding essential pitch pattern along with the measured pitch pattern, it became easier for the beginners to perceive aurally the tonal characters, which underlay the measured pitch patterns; 2) The bisyllabic word lists comprising only voiced consonants were edited, and the measured pitch patterns not interrupted by unvoiced consonants were displayed visually. These speech samples were useful in the early stages of tone discrimination learning. It was also ascertained that the tone discrimination was stimulated by paying attention to musical pitch perception.
The perceptual sensitivity to the prosodic cues in disambiguation of the ambiguous and the biased ambiguous sentences
Authors: Kang Sun mi , Kim Mi Hye , Kim Kee ho
Published: April 2012

This study explores the perceptual sensitivity to the prosodic cues in disambiguating the structurally ambiguous sentences by English native speakers and Korean learners of English. Also, this study aims to investigate that even the biased ambiguous interpretations due to their semantic factors were also affected by the prosodic cues. The perception experiment was conducted by the cognitive experimental tool, E-prime. In the perception test, one of the meanings of the sentences were presented on the screen, and then the acoustic stimuli were provided to the participants. The acoustic stimuli were given in two phases - the normal stimuli and the reinforced stimuli. The subjects were asked to judge the correspondence between the semantic and acoustic stimulus. The recognition rate increased, while the response time was shortened, when the reinforced stimuli were given. To be specific, English natives sensitively respond to the phrasal accent and phrase final lengthening, while Korean learners are sensitive to the substantial pause. With regarding to the biased ambiguous sentences, Korean learners do not rely on their baseline preference and easily shifted their resolution according to the prosodic factors they heard. while native speakers much rely on their internally fixed interpretation beside of the meticulous prosodic cues.
Adaptive equalization, tracking, and decoding for high-rate underwater acoustic communications
Authors: Singer Andrew
Published: April 2012

The interaction between equalization and decoding in the form of turbo-equalization has been shown to enable dramatic bit error rate (BER) improvements in high-rate underwater acoustic communication links. These improvements are particularly pronounced at lower SNR, higher data rate and in highly dynamic environments, where forward error correction can be leveraged to enable the receiver to maintain tracking and data recovery through deep fades or bursts of noise in the received signal. Platform mobility exacerbates these challenges, since the resulting broadband Doppler is manifested as a dynamic dilation and contraction of the modulated waveform, necessitating dynamic resamplingat the receiver to preserve symbol timing. In this talk, we present results from recent at-sea experiments in which time-varying Doppler compensation has been integrated into an adaptive turbo equalization receiver for both single-channel and multi-channel receiver systems.
Focusing, doppler shifts and bubble screening: Parameterizing surface reverberation in different wind regimes
Authors: Deane Grant , Preisig James
Published: April 2012

Advances in underwater acoustic communications systems can be based upon physical insight into the relationship between the acoustic channel and controlling environmental variables, such as wind and waves. In the mid-frequency band (3 kHz - 20 k Hz) and at relatively short ranges (order 10 water depths) in reverberant channels, gravity waves focus sound energy incident on the sea surface, creating intensifications, Doppler shifts and phase shifts in the reflected field. Breaking waves entrain bubbles into a sub-surface layer that attenuates and scatters sound, which tends to screen reflections from the surface and lessen the impact of these effects. Observations of the time-varying arrival intensity structure from an experiment conducted in the Martha's Vineyard Coastal Observatory will be presented along with model calculations made using the Kirchhoff approximation. Model calculations of wave-induced Doppler shifts and examples of bubble screening will be discussed. [Work supported by the ONR Ocean Acoustics Program].
A scaled mapping approach for treating sloping interfaces in parabolic equation solutions
Authors: Collis Jon M. , Moran Daniel
Published: April 2012

An area of research in ocean acoustics is on solution techniques for environments with sloping seafloors. In these range-dependent environments the oceanic waveguide varies in the direction of propagation and analytic solutions do not exist. In order to enforce continuity conditions at the seafloor the environment is approximated as a series of range-independent regions. An alternative to this approach, the mapping solution [M. D. Collins et al., JASA 107] applies a change of variables that results in a vertical translation of the environment and makes it easier to enforce ocean bottom interface conditions. An alternative mapping approach that uses a characteristic depth length scale is considered here. In contrast to the earlier mapping solution, this approach uses a change of variables in which the depth variable is scaled relative to the depth of the bottom interface. Along with the simplification of bottom interface conditions in both approaches, extra terms arising from the mapping are neglected, and hence a correction is applied in both to the calculated solution. The new approach is implemented in a parabolic equation solution and is benchmarked against existing solutions. The accuracy of this new approach is established initially for problems involving fluid sediments.
Dispersion deformation due to bottom model mismatching
Authors: Zhao Zhendong , Wu Jinrong , Shang Erchang , Ma Li
Published: April 2012

The development of MFP (Matched Field Processing) has played an important role in the inversion of the sediment parameters. However, how to characterize the effect of sediment on the propagation of sound is still far from the last answer. A popular solution is making use of the GA (Geoacoustic) model. In practice, it is always impossible to pre-know the layout of the real sediment, so a supposed model is used. For the narrow frequency band case, the supposed GA model may predict the sound field well. But in a broadband case, there will be error if the supposed model mismatches the real one, which will lead to dispersion deformation. Besides, the GA model involves many unknown parameters, especially for a complex model. To overcome such problems, a model-free method named RBC (Rapid Bottom Characteristic) based on only two parameters, the phase-shift parameter P and the absorption parameter Q in bottom reflection coefficient, has been provided. The effect of RBC for a broadband sound field is showed by simulation, and the problem of dispersion deformation is solved well. [This work was supported by NSFC under Grant No. 10874201 and No. 11074271]
Acoustic diode
Authors: Cheng Jianchun , Zhang Dong , Liang Bin , Guo Xiasheng , Tu Juan
Published: April 2012

Usually, waves can travel just as easily in either direction along a given path. The invention of electric diode, which acts as a one-way filter for the current flux, has marked the beginning of modern electronics and eventually led to worldwide revolutions in many aspects. Similar devices also exist for light and heat transmission. However, it is much more difficult to make such one-way devices for sound waves, another important form of classical wave with even longer research history than electric waves, because of the way sound waves move though a material. Recently, the first model of “acoustic diode” has been demonstrated both theoretically and experimentally to allow the acoustic energy to flow in only one direction. This device was fabricated by coupling a superlattice with a layer of ultrasound contrast agent microbubble suspension. A significant rectifying effect could be observed within two frequency bands at locations that agreed well with theoretical predictions. The development of the “acoustic diode” prototype will inspire the interests and investigations in the more practical and efficient acoustic rectifiers, which should have substantial significance for the applications of ultrasound devices in many practical areas such as medical ultrasound therapy and high resolution imaging.
Tsinghua University student design competition—Schools
Authors: Luo Jia , Zhao Xiufang , Zhang Shuo , Li Kun , Zhu Xiangdong
Published: April 2012

Armstrong (China) Investment Co., Ltd., with support from Tsinghua University sponsored a school design competition, and this represents the winning student entry. This competition was intended to encourage students to express their knowledge of architectural acoustics and noise control in the design of a school in which acoustical considerations are of significant importance. Design included considerations of 1) the general architectural building design including both shape and location of the building relative to transportation noise sources, and 2) the specific architectural acoustic design of rooms, including noise control both within and between rooms. The design scenario was for a new primary school designed to replace an older school building at a site near Tsinghua University. The primary school will include grade levels from 1 to 6, with approximately 1000 pupils. This school building will include normal classrooms (number and size based on student population and design standards), cafeteria, auditorium, library, music rooms, gym, dancing room, etc, as are normally found in such a primary school. The school will consist of a single building, which may be a multi-level building.
Sound absorption of periodically arranged flat surface and uneven surface
Authors: Wang Jingjing
Published: April 2012

Nowadays, thermally active concrete ceilings are frequently used in new buildings due to the requirement of thermal comfort and energy saving. But architectural design requires for planar surfaces so that the sound absorbers should not be installed below the ceiling even for guaranteeing the thermal efficiency. Thus a periodic arrangement of sound-absorbent strips or patches in concrete ceilings will be a good solution to this problem. The sound absorption of these two structures will be introduced in this report. Furthermore, a periodically uneven surface with rectangular profile is also commonly used at present, for example, as wooden floor. The sound absorbers can be hided in the grooves to control the acoustic environment. This configuration satisfies people's requirement of seeing the wood ceiling. The sound absorption of this groove structure will be introduced in this report as well. Besides, a parametric survey has been down on the performance of the periodically groove structure and porous absorber. Based on this survey, optimized examples for application are suggested.
On the measurement of directivity index for adaptive directional hearing aids
Authors: Xu Buye , Merks Ivo , Zhang Tao
Published: April 2012

Adaptive directional microphone arrays have been widely utilized in hearing aids to help wearers understand speech in noisy environments. However, a practical and objective way of measuring the benefit of this technique is not obvious. One commonly used measure for directional microphone arrays is directivity index (DI), which evaluate the arrays' capability to attenuate a diffuse noise field. However, the DI has rarely been considered for the Adaptive directional microphone arrays because a truly diffuse noise field is required for the measurement. This paper investigates the feasibility of measuring the DI of adaptive directional hearing aids in a diffuse noise field generated by a loudspeaker array playing uncorrelated noise signals simultaneously. The requirement for the degree of diffuseness of the noise field is studied based on numerical simulations for first-order and second-order adaptive microphone arrays. The possibility of measuring the DI in both anechoic and non-anechoic conditions is investigated. The accuracy of the proposed approach is further discussed.
Classification of three tuna species in enclosures by using target strength spectra measured by a broadband split-beam system
Authors: Imaizumi Tomohito , Abe Koki , Wang Yong , Ito Masanori , Matsuo Ikuo , Nishimori Yasushi , Akamatsu Tomonari
Published: April 2012

The selective capture of tunas; bigeye tuna (Thunnus obesus), skip jack tuna (Katsuwonus pelamis) and yellow fin tuna ((Thunnus albacares) is important for Japanese seine net fisheries. Classification of the species composition by using acoustic information before catching them will significantly contribute for the selective catch. Target strength spectra (TSSP) of each species were measured by a broadband split beam system. Each tuna species was separately kept in a enclosure, which sized 8 × 8 m square and approximately 5 m in depth. This system was able to measure not only TSSP but also a swimming track of individual in 3D. The differences of TSSP among three species were confirmed. For example, the target strength value of begeye whose tilt angle was 0 degree about 10 dB higher than skip jack tuna one. Swimbladder sizes were measured for each species by soft X-ray because skip jack tuna are physoclist species, and others are physostome species. There were differences of the swimbladder shape between bigeye tuna and yellow fin tuna. The TSSP seemed to be depend on not only body size (fork length), but also swimbladder shape. The TSSP could be useful information to classify among tunas.
Vibration energy of metamaterials with negative effective parameters
Authors: Bobrovnitskii Yuri I.
Published: April 2012

Metamaterials, having unusual wave properties and offering promising applications, received much attention in recent years. However there are many questions begging for answer. Some of them concerning energy characteristics of metamaterials with negative inertial and elastic effective parameters are examined in this paper. The main result of the paper represent simple equations that express the vibration (acoustic) energy of a metamaterial through its effective density and elastic modules and their derivatives with respect to frequency. Special attention is paid to negative values of these parameters. Revealed are rather severe restrictions on their possible values that follow from the derived equations. The results are illustrated on metamaterials known from literature.
Measuring the effect of instruction
Authors: Adams Wendy K.
Published: April 2012

Teaching as a science: As part of the endless pursuit of teaching excellence faculty develop and each year modify course materials in an attempt to help students learn as much science as possible in a semester. The goals include teaching the content as well as an appreciation for the science and how it connects to our everyday lives. At the same time we expect our students to learn what it is to do science and be a scientist. How can we measure the effectiveness of our teaching methods and compare them from year to year and from university to university? Since the mid-90's physics instructors have been using the FCI (Force Concept Inventory) to measure something, conceptual understanding maybe, in first semester introductory physics. Many other conceptual inventories have followed. In 2005 the CLASS was developed to measure student's perceptions and beliefs about learning physics. Quite often faculty are surprised and disappointed in the outcomes of these measures. As a colleague so eloquently stated, “Students have a way of disappointing you.” In this presentation, I will briefly present my approach to teaching with interactive engagement and how I have attempted to measure the results using a combination of measures.
An interactive method for teaching circuit model construction for complex interconnected acoustic systems
Authors: Wilson Preston S.
Published: April 2012

Complex, highly interconnected acoustic systems can be difficult to model for students and inexperience practitioners. The systematic lumped-element circuit model construction method presented here is easy to learn and teach, and allows for rapid, error-free circuit model construction. The present author discovered the method in a book by Mario Rossi [Acoustics and Electroacoustics, Artech House Publishers (1988)] and has included it in the electroacoustic transducers course taught at the University of Texas at Austin since 2003. This method has been effective in this course and utilizes two types of effective instruction discussed in the scientific education literature: the use of interactive engagement and visual models.
Noise policy in Germany
Authors: Fabris Christian
Published: April 2012

This paper is a summary of the principle and main noise policy instruments in Germany. It attempts to show a simple model of these instruments, embedded both in European and German federal state legislation. German legislation on noise is divided into several laws, ordinances and other regulations concerning the various sources of noise (traffic, industry, mobile machinery, sports grounds, etc.) Noise emissions are generally governed by European legislation. Examples are the so-called “Outdoor Directive” and the “Energy-using-Products Directive”. Other laws limit the noise exposure from noise sources. Another example is the implementation of the Environmental Noise Directive into German noise policy. This contains the principles to create feasible noise abatement plans considering public concerns. The planning of traffic routes as the most annoying noise sources in Germany is regulated in particular laws and ordinances for the respective sources. Noise exposure of the most stationary noise sources is limited by a national instrument of legislation, the “Technical Instructions on Noise Abatement – TA Laerm”. There are also some governmental economic development schemes which are related to noise criteria. Last but not least there is the environmental label “Blue Angel”, which awards several products which are outstanding quiet in their product family.
The resonance hole with membrane; a distinctive feature of East Asian transverse flutes
Authors: Odaka Akiko
Published: April 2012

The East Asia region, except for mainland Japan, has transverse flutes which have resonance holes with a membrane. The dizi in China, the taegum in Korea and the fansō in Okinawa are good examples of this. Generally, a reed caliber epidermis is used as the membrane. Chinese dizi players point out that a reed epidermis creates a louder and clearer resonance than other materials. In China, transverse flutes with a resonance hole appeared in the Song dynasty, when Chinese theatrical music became popular. A transverse flute was played as the main accompaniment with other stringed and percussion musical instruments. Ordinarily, theatrical plays were performed outside. It was under these circumstances that the resonance hole was added, creating a louder, clearer sound. The Korean taegum is thought to have existed since the Three Kingdoms period (57B.C.-668). Its resonance creates variegated timbre combined with taegum's unique vibrato techniques. The Okinawan fansō has its origin in the Chinese dizi of the Ming dynasty. However, currently, musicians play an improved fansō, which has no resonant holes. This presentation will show the historical and musical background of the resonance hole and will include music recordings.
Vibro-acoustic analysis of wind instruments with membranes on resonance holes
Authors: Samejima Toshiya , Ide Shiori , Araki Yozo
Published: April 2012

Some Asian wind instruments have a membrane glued over a special hole. A Japanese flute “Shino-bue” has a special hole called “resonance hole” between the mouth-hole and the first tone-hole. The resonance hole is covered with a bamboo paper membrane called “Chikushi”. “Dizi” in China and “Taegum” in Korea also have a similar structure. The vibration of the membranes gives the wind instruments their characteristic bright timbre, thereby making them distinctive from comparable Western instruments. To investigate the influence of the membrane upon acoustical properties of such a wind instrument more qualitatively, this paper develops a numerical method for calculating the sound field around a wind instrument with a membrane on its resonance hole, as a vibro-acoustic system. This method couples, the integral equation derived from the normally differentiated Kirchhoff-Huygens formula for the sound field around the thin obstacle, with a theoretical solution of the vibration equation for the membrane. The formulation of the developed method is confirmed by comparing numerical results with measured results for a simple model of the wind instrument. Effects of the tension of the membrane, the size and location of the resonance hole, are discussed through numerical calculations using the developed method.
Social networks and networking of scientists: benefits and drawbacks
Authors: Hollstein Betina
Published: April 2012

Topic of the presentation is the contribution of social networks and social network analysis with regard to global change and the future of Acoustics. What are the outcomes of coopera-tion and networking of scientists and how is networking be enhanced? The paper elaborates on different types of social networks (among scientists and among science and other societal actors, like industry, political actors etc.) and its respective outcomes. How do networks matter and what are gains and possible losses of networking? Emphasis is placed on different cultures and contexts of networking. With respect to governance of networks I distinguish between “organic” networks and “organized” networks. Finally, consequences for networking between scientists are discussed.
A prospect of the future of automotive sound quality development
Authors: Kang Koo Tae
Published: April 2012

In the development of vehicle sound design, sound quality is getting more important as opposed to the traditional sound level design. To get the proper sound quality with the vehicle image, the sound targets of the vehicle is needed to be defined appropriately in the vehicle level, system levels, etc., which become the core part in the vehicle design procedure. In sound design of the electrified vehicles including fuel cell vehicle, hybrid vehicle, extended range EV, and pure EV, artificial sound design both for vehicle interior and exterior, gain popularities for pedestrian protections as well as the driver satisfactions. As for the sound characteristics of the future vehicles, new noise sources are expected to be more concerns than powertrain noise sources with reduced noise level. Thus, in design of future vehicles, the efforts of the vehicle sound development should shift from the traditional sound level reduction to sound quality design and sound synthesis dealing with new noise sources.
Continous separation of microparticles using standing surface acoustic wave in microchannel
Authors: Shin Sehyun , Nam Jeonghun , Lim Hyunjung
Published: April 2012

Manipulation of microparticles in heterogeneous complex colloids has become important in various research fields that use microfluidic devices, such as biochemical analyses and clinical diagnosis. Although various techniques for microparticle manipulation in microfluidics have been developed, further advancements are still required for highly accurate analyses. Microparticle manipulation techniques, which include microparticle focusing, tweezing, and separation, using surface acoustic waves (SAWs) have emerged and gained attention. Since SAW-based microfluidics has advantages of being non-invasive, being harmless to particles, and consuming low power intensity and so on, it has great potential for further advancements, especially for biochemical research field. Recently, SAW-based techniques which can manipulate a variety of microparticles have been developed in my group. To predict the behavior of microparticles in microchannel flow, advanced analytical model was developed, and validated with experimental results. In the experiment, the heterogeneous sample, which includes blood, engineering particles, encapsulated cells, sperms, etc., were separated successfully into homogeneous sample with the separation efficiency over 99%. In this presentation, developments of SAW-based microparticle manipulation techniques to date and recent results of my group will be reviewed. In addition, some recommendations for future work of novel applications of SAW will be suggested. Acknowledgement This research was supported by Nano. Material Technology Development Program (Green Nano Technology Development Program) through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (No. 2011-0020090)
Acoustically-driven microcentrifugation
Authors: Yeo Leslie , Friend James
Published: April 2012

A microcentrifugation technique is demonstrated in which symmetry breaking of a planar surface acoustic wave (SAW) propagating along a piezoelectric substrate can generate rotational acoustic streaming in a nanoliter drop. The azimuthal flow is rapid, with linear velocities of several cm/s - such fast azimuthal streaming, shown to be chaotic beyond a threshold power, can be used to generate intense micromixing within the drop. Indeed, we show that the rate and yield of a variety of distinct chemical and biochemical reaction classes far exceed that obtained using ultrasonic or microwave-assisted mixing, and with considerably lower power. Further, samples can be atomised from a cheap paper-based microfluidic system, thus demonstrating the potential for direct interfacing with mass spectrometry following chemical synthesis. The microcentrifugation effect can also be exploited for particle manipulation and sorting. This is demonstrated for bioparticle concentration for rapid and sensitive pathogen detection or the separation of red blood cells from plasma for miniaturized diagnostic applications. In addition, it is also possible to separate two different particle species by size by exploiting the unique size-dependent scaling between the acoustic and drag forces acting on the particle.
Acoustic bubble sorting: contrast enrichment by primary radiation forces
Authors: Segers Tim , Versluis Michel
Published: April 2012

Ultrasound contrast agents consist of a suspension of encapsulated microbubbles with radii ranging from 1 to 10 μm. Medical transducers typically operate at a single frequency, consequently only a small selection of bubbles resonates to the driving ultrasound frequency. Thus, the sensitivity can be improved by narrowing down the size distribution. Here, a simple lab-on-a-chip method is presented to acoustically sort microbubbles on-line by a piezoelectric actuator positioned perpendicular to a microfluidic channel in a PDMS chip. Bubbles are produced in a flow focusing geometry at a rate of 500 bubbles per second. The bubbles are characterized in the unbounded fluid to provide physical input parameters for a force balance model. Good agreement is found with the experimentally observed displacement as a function of the bubble radius in free space as well as in the confinement of the sorting chip. This novel sorting strategy may lead to an overall improvement of the sensitivity of contrast echo by at least an order of magnitude.
The distance-dependence of interaural level difference cues to sound location and their encoding by neurons the inferior colliculus – implications for the Duplex theory
Authors: Jones Heath G. , Thornton Jennifer L. , Koka Kanthaiah , Tollin Daniel J.
Published: April 2012

The Duplex theory posits that low- and high-frequency sounds are localized using two different acoustical cues, interaural time (ITDs) and level (ILDs) differences, respectively. Anatomically, ITDs and ILDs are separately encoded in two parallel pathways consistent with ecological and efficiency principles which state that neural systems evolved strategies to represent the full spectrum of sensory signals as experienced by an organism in its natural habitat. ILDs are location and frequency dependent such that lower and higher frequencies exhibit smaller and larger ILDs, respectively. Neurons throughout the auditory neuraxis encode ILDs for high-frequency sounds. However, although low-frequency ILDs are negligible, humans are quite sensitive to them and physiological studies report low-frequency ILD sensitive neurons. The presence of such neurons is at odds with the Duplex theory and ecological and efficiency principles. We suggest these discrepancies arise from inadequate understanding of the ecological acoustical environment. Via measurements in the chinchilla of acoustical ILDs and their encoding by inferior colliculus neurons the hypothesis is explored that low-frequency ILDs become useful when sound source distance is varied. We demonstrate that a population of neurons is sufficient to encode the frequency-dependent range of ILDs that would be experienced as a function of location and distance. (R01-DC01155)
Test study on the recording acoustics of Urheen
Authors: Zhang Jingying , Meng Zihou
Published: April 2012

The acoustics of the instrument recording involves acoustic characteristics of the instrument as a sound source, the microphone characteristics for the recording, and the room acoustics of the recording studio. For the purpose to optimize the recording localization as well as the its setting and balance between instruments in Chinese orchestra, a series of test are carried out to measure the radiation directivity, the harmonic directivity and the sound power level of the urheen which is the most important instrument in Chinese orchestra. Based on the listening tests the best reverberation for urheen music is discussed to support the selection of recording environment and the post processing of the recorded music. A group of microphones are evaluated based on a listening test with the urheen music of different styles to search the appropriate microphone for urheen music recording. According to the study of recording acoustics of urheen, the guideline for a better uhreen recording is given.
Motion analysis for emotional performance of snare drums using a Motion Averaging Method
Authors: Miura Masanobu , Mito Yuki , Kawakami Hiroshi
Published: April 2012

Proposed here is a “Motion Averaging Method”, for the analysis of motion data of musical performance on expressing emotion obtained by a motion capture system. The method is made to analyze the motion on expressing any emotion on playing the snare drum. Specifically, the motions for an etude with each of emotion (tenderness/happiness/anger/fear/sadness) played by three trained percussionists were recorded by using a motion capture system. Obtained data (*.trc) were corrected and then adjusted among them by shifting and rotating player's position, so as to ignore the difference of position of players on recording. Moreover, the difference among each performance in time is uniformed by stretching (expanding or contracting) the motion data based on the impact time of the performance. Expanded or contracted data were then averaged for each emotion. Obtained motion is called an “averaged motion”, which shows common motion of the performance on expressing each of an emotion. Features of the averaged motions for each emotion are measured by observing differences and tendencies among each player were investigated. This study shows a list of features of motion on playing the snare drum by three trained players. We also discuss about the application of the method.
The effects of the source and ground parameters on outdoor sound propagation using the FDTD
Authors: Kaifeng Han , Xinwu Zeng , Zhenfu Zhang
Published: April 2012

The sound propagation outdoors is widely studied in several areas such as transportation noise mitigation, biological studies, security and military activities. Several special factors are important when sound waves propagate more-or-less horizontally near the ground, such as ground characteristics, the use of sources and so on. The simplest effect of the ground on the sound field is the interference between the direct and reflected sound fields. However, the ground surfaces are neither rigid nor impervious to air flow; it will cause higher sound energy loss. Secondly, the parameters of the source distribution and the frequency emission also determine the amount of loss. To quantify the influences of the source parameters and inhomogeneous ground conditions on the sound field outdoors, a practical FDTD implementation is constructed in this paper. The mixed influence of ground characteristics and source conditions are then included. The numerical results showed the source distribution and the frequency had large effects on the actual sound pressure measurement in the specific situation. The ground boundary conditions are the main effects on the basic phenomena of outdoor sound propagation.
A practical web-based workflow allowing authorities to meet the requirements of the END for 2012 and beyond
Authors: HOAR Chris
Published: April 2012

Local, state and national authorities and organisations, are increasingly searching for technology-based approaches to meet the legislative and practical requirements associated with addressing community noise issues. This has been a necessity rather than luxury as the breadth and depth of activities that need to be performed by authorities has expanded to the point where it is no longer feasible to assign these to small specialised teams. The ODEN system discussed in this paper addresses these needs by providing an easy-to-use, accessible set of web-based tools that generalist and specialist users alike can use to perform required tasks. Utilising the LimA calculation engine, the system provides the ability for users to edit and manipulate model input data, perform a variety of road, rail, aircraft and industry noise calculations, generate reports and statistical analyses and visualize results as maps and 3d views. The system provides a framework which allows central mapping authorities to coordinate the activities and workflows supporting strategic noise mapping. For example by distributing workflows to stakeholder communities, the system assists authorities in preparing base data, provides tools for involved agencies to update this base data and finally tools to produce EU compliant noise maps and reports.
Surface acoustic wave actuated miniaturized lab-on-a-disc (miniLOAD)
Authors: Glass Nick , Shilton Richie , Chan Peggy , Friend James , Yeo Leslie
Published: April 2012

Lab-on-a-chip systems offer much potential in next generation diagnostics. Miniaturizing laboratory processes can realize reductions in test times, sample size and cost. This allows for new possibilities such as real time and point of care diagnostic systems. However, lab-on-a-chip systems often require large laboratory scale equipment to drive flow for microfluidic processes. To overcome this challenge, a miniaturized centrifugal based microfluidic platform has been developed. Surface acoustic waves (SAW) are used to generate rotation in a fluid layer, which, in turn, drives the rotation of a disc. Initially, Mylar discs of 5 mm diameter were rotated to greater than 2000 rpm. SU8 discs of dimensions ranging from 250 microns to 10 mm were also actuation and speeds of the order of 10 000 rpm were recorded. The larger 10 mm discs were patterned with various microfluidic structures through the use of photolithography. Common lab-on-a-chip processes are demonstrated including capillary valving, mixing and particle concentration. Currently, work is being carried out to do some basic biological assays on the miniaturized Lab-on-a-disc system.
Noise-induced increase in human auditory evoked fields
Authors: Alain Claude
Published: April 2012

Background noise is usually detrimental to auditory perception. However, psychophysical studies have shown that in some circumstances low levels of broadband noise may improve signal detection. Here, we measured auditory evoked fields (AEFs) while participants listened passively (no response required) to stimuli embedded in low or moderate levels of continuous Gaussian noise. As a control condition, the stimuli were also presented without background noise. The AEFs were modeled with a pair of dipoles in the superior temporal plane and the effects of noise on the amplitude and latency of the resulting source waveforms were examined. The results show that low-level background noise enhanced AEF amplitude. The effects of continuous low level Gaussian noise on AEF amplitudes were comparable for young and older adults. Possible explanations for the noise-induced increase in AEF amplitude are a lengthening of the temporal integration window and/or efferent feedback connections between the auditory cortex and lower auditory centers to enhance the signal-to-noise ratio.
Speech in noise and ease of language understanding: when and how working memory capacity plays a role
Authors: Rönnberg Jerker , Sörqvist Patrik , Dahlström Örjan , Rudner Mary , Johnsrude Ingrid , Stenfelt Stefan
Published: April 2012

A working memory based model for Ease of Language Understanding (ELU) has been developed (Rönnberg, 2003; Rönnberg et al., 2008; Rönnberg et al., 2011). It predicts that speech understanding in adverse, mismatching noise conditions is dependent on explicit processing resources such as working memory capacity (WMC). This presentation will examine the details of this prediction by addressing some recent data on (1) how brainstem responses are modulated by working memory load and WMC, (2) how cortical correlates of speech understanding in noise are modulated by WMC, and (3) how WMC determines episodic long-term memory for spoken discourse masked by speech.
Active vibration control experiments of a large flexible vibration isolation structure
Authors: Zhou Liubin , Yang Tiejun , Shi Hui , Yuan Wanpeng , Liu Zhigang
Published: April 2012

An active control system based on Filtered-x LMS algorithm with off-line secondary path modeling is proposed and applied in active vibration control of a large flexible vibration isolation structure, which is an isolation system attached on a large flexible structure supported by twenty-six air springs. Details of the large flexible vibration isolation system, the features of the active system, and experimental investigation including the single-input single-output and multi-input multi-output experiments are presented in this paper. The experimental results show that vertical vibration levels of error sensor positions on the flexible foundation can be reduced greatly. At last some results are presented and discussed.
Evaluation of vehicle seat rattle noise using coherence function technique
Authors: Park Jin-su , Jeong Jae-Eun , Lee Jong-Won , Yang In-Hyung , Oh Jae-Eung
Published: April 2012

Recently, customers have been concerned about vehicle NVH depending on vehicle designing and manufacturing technologies development. In choosing vehicle, vehicle NVH is becoming the most important factor to customers. Especially, a seat is the final stage of vibration transfer path to passengers from all sources of vibration like engine, transmission and etc. And seat is the nearest component from driver's ear. For this reason, seat is the most important component that directly related to ride comfort for passengers. And driver can be influenced sensitively by BSR caused by seat. Thus, evaluating the vibration characteristics of vehicle seat and BSR caused by vehicle seat is necessary to reduce the seat BSR. The rattle noise occurred from seat has evaluated through sound source visualization and multi-dimensional spectral analysis - coherence function technique in this paper. Vibration characteristics of the seat has verified through modal test.
Noise and vibration control by rail dampers
Authors: Ho Wilson , Wong Banting , England David , Pang Alson
Published: April 2012

MTR Corporation and Wilson Acoustic Limited launched a project to investigate the effect of rail dampers on noise reduction and rail corrugation growth in an operational metro railway at a 300m radius curved track. Corrugation was measured by Corrugation Analysis Trolley (CAT) every month throughout a 6-month grinding cycle. Corrugation of wavelength 50-80mm was observed at the low rail, corresponding to 250-400Hz at train speed of 70km/hr. No corrugation was observed at the high rail. Corrugation growth rate was reduced by 45% after installation of rail dampers. In contrary to rail corrugation models at tangent track which predict exponential growth with time, corrugation growth at the test site is approximately linear. Corrugation at the test site was thought to be the combined effect of low vertical response and high lateral response at 250–400Hz, resulting in periodic fluctuation of normal contact force, minimal normal contact force is accompanied by lateral sliding causing frictional wear. Rail dampers have no apparent effect on the vertical response at anti-resonance 250–400Hz, but significantly reduce the lateral response. Measurement results and literature reviews suggest that using rail dampers to decrease lateral response could reduce growth of short pitched corrugation at sharp curves.