bluuebunny/crossref_metadata_2025 huggingface dataset:
A spectral analysis of the apical vowel in Yongding Hakka
Authors: Lee Wai-Sum , Zee Eric
Published: April 2012

The so-called apical vowels occur in a large number of Chinese dialects, including Yongding Hakka spoken in the southwest of Fujian Province in southeastern China. A main difference between apical vowel and dorsal vowels is in the fact that the former is a syllabic approximant with a linguo-palatal contact pattern of either laminal alveolar or apical postalveolar. Phonologically, both vowel types function as the syllable nucleus. The paper analyzes the spectral characteristics of the apical vowel [???] in Yongding Hakka. Preliminary results show that the F-pattern of the apical vowel differs from that of the dorsal [i] substantially. The average F1, F2, and F3 values of five repetitions of [???] from 10 male speakers are 500.9 Hz, 1323.4 Hz, and 2722.9 Hz, but 339.8 Hz, 2362.6 Hz, and 3269.6 Hz for [i]. Thus, a large difference is in F2. This is also true for female speakers of Yongding, in that the average F-values are 567.9 Hz, 1473.2 Hz, and 3242.6 Hz for [???] and 405.4 Hz, 2362.1 Hz, and 3269.6 Hz for [i]. The spectral data for the apical vowel in Yongding Hakka will be compared with those for the apical vowels in other Chinese dialects, such as Beijing Mandarin.
Modeling Mandarin Tone 2 and Tone 3 from natural productions with variability
Authors: Zhao Tian (Christina) , Wright Richard , Kuhl Patricia
Published: April 2012

Naturally produced speech is highly variable. Previous descriptions of lexical tone contours tend to be based on a single production or productions from a single speaker. Here we describe a method to model Mandarin Tone 2 and Tone 3 accounting for both intra- and inter-speaker variability. Five female speakers, born and raised in Beijing, were recorded reading 60 syllables both in Tone 2 and Tone 3 (real Chinese words) at two different speeds. The pitch contour of each production was first extracted using Praat. All the contours for Tone 2 and Tone 3 were then plotted in normalized time against frequency values. As expected, the normalized time vs. frequency plot for each tone exhibited large variability. Using the Matlab curve fitting toolbox, the 6th polynomial function was chosen to achieve the best goodness of fit with the current data. [Research supported by NSF.]
Effects of prosodic position on the production of Si-Xien Hakka tones at phrase level
Authors: Yu Hsiu-min , Chiang Chen-yu , Wang Yih-ru , Chen Sin-horng
Published: April 2012

This study examined the effects of prosodic position on duration and F0 of the six tones in Si-Xien Hakka. Each of the tones was placed in the initial, medial, and final positions of a three-syllable phrase/clause, which constituted the first part of a sentence with the [δδδ, δδδ] structure. The results showed that F0 lowering and lengthening were found at domain final position. The final lengthening allowed the offset of the low-rising tones to reach a higher F0 target, not attainable by those in other prosodic positions. Also in this final position the high level tones exhibited a real flap shape due to the greater coarticulation resistance caused by the following boundary breaks. Furthermore, the F0 decreasing rate of the falling tones was found to vary according to domain position: the F0 descended the fastest at domain medial position and the slowest at final position, except for the high checked tones, which showed the same rate at domain-initial and –final positions. This reveals that the vibration of the vocal folds, reflected by the F0 decreasing rate, started from the initial position, gradually speeded up to the highest rate at medial position and then slowed down till the pre-boundary domain-final one.
Properties of the duration of pauses in the recitation of a Japanese text
Authors: Hiki Shizuo , Kakita Kuniko
Published: April 2012

The present study investigated the properties of the duration of pauses in the recitation of a Japanese text. The text employed was the “panphonic” version of `The North Wind and the Sun' created for the illustration of the IPA of Japanese (Tokyo dialect) consonants (S. Hiki, K. Kakita and H. Okada, Proc. 7th Int'l Cong. on Phonetic Sciences, Hong Kong, 2011, 871-873). The text consisted of eight sentences (294 syllables), was easy to read aloud, and could be read in one minute at normal speaking rate. In the text, tonal segments were specified by boundary symbols. On the basis of these boundary symbols, as well as other factors such as breathing, possible pause locations were determined. A native speaker of Japanese read the text, inserting pauses at these locations. The speaker chose the pause duration that was most natural in each location. The relationship between the pause duration and the preceding utterance duration was analyzed. It was revealed that the accumulated duration of pause segments converges at about 40% of that of speech segments towards the end of one minute recitation. The present result provides a useful framework for extending the analysis to spontaneous speech.
Acoustic analysis of adults imitating infants: a cross-linguistic perspective
Authors: Engdahl Johan , Bjerva Johannes , Marklund Ellen , Byström Emil , Lacerda Francisco
Published: April 2012

The present study investigates adult imitations of infant vocalizations in a cross-linguistic perspective. Japanese-learning and Swedish-learning infants were recorded at ages 16-21 and 78-79 weeks. Vowel-like utterances (n=210) were selected from the recordings and presented to Japanese (n=3) and Swedish (n=3) adults. The adults were asked to imitate what they heard, simulating a spontaneous feedback situation between caregiver and infant. Formant data (F1 and F2) was extracted from all utterances and validated by comparing original and formant re-synthesized utterances. The data was normalized for fundamental frequency and time, and the accumulated spectral difference was calculated between each infant utterance and each imitation of that utterance. The mean spectral difference was calculated and compared, grouped by native language of infant and adult, as well as age of the infant. Preliminary results show smaller spectral difference in the imitations of older infants compared to imitations of the younger group, regardless of infant and adult native language. This may be explained by the increasing stability and more speech-like quality of infants' vocalizations as they grow older (and thus have been exposed to their native language for a longer period of time), making their utterances easier for adults to imitate.
Acoustic effects of neuromuscular electrical stimulation after a vocal loading task
Authors: Gorham-Rowan Mary , Morris Richard , Fowler Linda
Published: April 2012

Recent studies have examined the application of neuromuscular electrical stimulation (NMES) to treat individuals with voice disorders. Appropriate protocols should be established for effective use of NMES. The purpose of this study was to use acoustic data to evaluate the effectiveness of NMES to the anterior neck in reducing vocal fatigue and muscle soreness following a prolonged reading task. Recordings were taken from two groups of talkers. Both groups completed a 45 minute oral reading task, then 11 subjects underwent a 15 minute NMES session, another group of 11 subjects completed the reading task only. Audio recordings were made before the reading task, after the reading task, and after the final 15 minutes. Acoustic measures of recordings included fundamental frequency, relative speech amplitude, cepstral level, H1-H2, H1-A1, and H1-A3. Preliminary results indicate increases in fundamental frequency and relative speech amplitude at the end of the reading task relative to pre- and post-session levels. The increases were greater among subjects receiving NMES.
Dynamical behavior in hemilarynx experiments with the false vocal folds attached
Authors: Döllinger Michael , Berry David A.
Published: April 2012

Previously, changes in vibrational parameters were reported as a function of varying glottal conditions in hemilarynx experiments (Döllinger and Berry, J Acoust Soc Am, 130(4):2440). Now, dynamical changes will be reported with the false vocal folds still attached, and the results will be contrasted with the results of the previous study. For two different larynges in which the false vocal folds remained intact during sustained phonation, vibrational output was statistically analyzed as a function of glottal airflow, adduction forces, and elongation forces. Global parameters were computed, including empirical eigenfunctions, fundamental frequency, subglottal pressure, and sound intensity level. Similarly, local parameters were analysed at individual locations, including displacements, velocities and accelerations. The recordings were obtained using a digital high-speed camera. Increased airflow resulted in significant statistical changes in all parameter values except the empirical eigenfunctions. For increased adduction and lower elongation forces, the local parameters increased more than for the higher elongation forces. As compared to experiments without false vocal folds, these experiments exhibited more marked and consistent dynamical changes. This result suggests that the false vocal folds may have a stabilizing influence on the vibratory behavior of the vocal folds, perhaps due to nonlinear feedback with the supraglottal airflow.
Modified S transform for time-frequency analysis of borehole flexural waves dispersion
Authors: Assous Said , Elkington Peter
Published: April 2012

Guided wave propagation usually exhibits dispersive behaviour. The time-varying spectral components of dispersive waves have been characterized effectively using the time-frequency approach; the short-time Fourier transform (STFT) and the continuous wavelet transform (CWT) are commonly used for this purpose. However, the resulting energy distributions suffer from poor resolution related to the uncertainty principle, and this complicates the allocation of energy to individual propagation modes especially when the dispersion curves of these modes are close to each other in the time-frequency domain (in which case the separation becomes a challenge). Therefore there is a need for high resolution time-frequency techniques. To meet this challenge we introduce a modified version of the S transform, a method which combines the advantage of the STFT and CWT but with greater resolution. An adaptive algorithm is presented which identifies frequency regions of interest related to different energy modes, and employs the modified S transform to a dispersion curve model to extract the proportional energy distribution of a specific mode from a multimode dispersive wave signal. The effectiveness of this approach is demonstrated on dispersive flexural waves obtained from an acoustic borehole logging tool.
Design and deployment of infrasonic sensor monitoring network in China
Authors: Feng Haonan , Yang Yichun , Men Chunlian
Published: April 2012

The Infrasonic Monitoring Network (IMN) in China is under construction to detect, identify and located the signals generated by natural disasters. Presently, fifteen sensors are operational and transmitting real time data to Central Data Centre (CDC) in Beijing. Each sensor station is composed of one infrasonic sensor, one humidity and temperature sensor, one digital sampling and transmitting device, which collects and delivers real-time continuous infrasonic, temperature, humidity, GPS raw data to CDC. IMN is designed as a robust sensor network optimized for rapid deployment and provides long-term information monitoring; the system supports data acquisition with GMT time and is remotely configurable. Its high performance has been demonstrated in the initial deployment experience and preliminary analysis of sampling data.
Third-order nonlinear IIR filter for compensating nonlinear distortions of loudspeaker system
Authors: Iwai Kenta , Kajikawa Yoshinobu
Published: April 2012

In this paper, we propose a 3rd-order nonlinear IIR filter for compensating nonlinear distortions of loudspeaker system. The proposed filter is derived from the nonlinear differential equation of the loudspeaker system. The conventional filter, which is called the 2nd-order nonlinear IIR filter, cannot reduce nonlinear distortions at high frequencies because this filter does not include the nonlinearity of the self-inductance of the loudspeaker system. On the other hand, the proposed filter includes the effect of the self-inductance and can reduce nonlinear distortions at high frequencies. Experimental results demonstrate that the proposed filter can reduce intermodulation distortions by 2 dB at high frequencies.
Indoor beamformer design using room simulators
Authors: Li Zhibao , Yiu Cedric , Leung Randolph , Nordholm Sven
Published: April 2012

Broadband microphone array provides an important means of hands-free speech acquisition via spatial beamforming techniques. There are many different approaches for the design of near-field broadband beamformers. One method is based on the wave propagation model using a direct path transfer function. However, as signals are corrupted by different interfering noise, room reverberation plays a particular important role for indoor applications even if there is no another speaker around. Image-source method is one simple but effective approach for room acoustic simulation. It is also possible to employ a wave-based model for the simulation. In this paper, we will study different room simulators and employ them for the design of indoor beamformers.
The 2009 Philippine Sea Pilot Study/Engineering Test and the 2010 Philippine Sea Experiment: University of Washington cruises
Authors: Mercer James , Andrew Rex , Buck Linda , D'Spain Gerald , Dzieciuch Matthew , Ganse Andy , Henyey Frank , White Andrew , Worcester Peter
Published: April 2012

Investigators at the University of Washington's Applied Physics Laboratory collaborated with scientists from the Scripps Institution of Oceanography during the 2009 Philippine Sea Pilot Study/Engineering Test and the 2010 Philippine Sea Experiment. The focus of both efforts was to collect well controlled low-frequency acoustic propagation data and detailed environmental information. The data from these cruises are presently being analyzed in the interests of: horizontal statistics of ocean spice as measured on a towed conductivity-temperature-depth (pressure) chain, fluctuation measures of low-frequency broadband ocean acoustic signals, bottom properties, and associated theoretical developments. This presentation will outline the experimental plans for each year, discuss preliminary analysis results, and provide an introduction for more detailed presentations in the remainder of this session. [Work supported by ONR.]
The ocean bottom seismometer augmentation of the Philippine Sea experiment
Authors: Stephen Ralph , Bolmer Tom , Worcester Peter , Dzieciuch Matt , Carey Scott , Moskovitz Brianne , McPeak Sean , Campbell Richard , Aaron Ernest , Kemp John
Published: April 2012

The goal of the Ocean Bottom Seismometer Augmentation of the Philippine Sea Experiment (OBSAPS) was to study the coherence and depth dependence of deep-water ambient noise, in the band from 0.03 - 80Hz, and signals, in the band from 50-400Hz. The cruise sailed Kaohsiung to Kaohsiung, April 29 to May 16, 2011. A fifteen element OBSAPS - Distributed Vertical Line Array (O-DVLA) with hydrophone modules from 12 to 852m above the seafloor was deployed in the Philippine Sea near 21degN, 126degE. Four short-period Ocean Bottom Seismometers (OBSs) and two long-period OBSs were deployed at 2km range from the O-DVLA. All of the OBSs had three-component inertial sensors and an acoustic pressure sensor. Three of the short period OBSs also had an external, autonomously recording hydrophone module identical to the hydrophone modules on the O-DVLA. The 12 day transmission program, using a J15-3 acoustic source, consisted of various M-sequences from 75.5 to 310Hz. Eight radial lines, a Star of David pattern, and nine station stops were transmitted out to 50km range. One radial line and nine more station stops were transmitted out to 250km range. Examples of possible Deep Seafloor Arrivals will be discussed. [Work supported by ONR.]
Towed array propagation measurements and modelling in the Philippine Sea
Authors: Heaney Kevin D. , Campbell Richard L. , Baggeroer Arthur B. , Steven Ralph , Scheer Edward , Worcester Peter , Dzieciuch Matthew
Published: April 2012

During the PhilSea09 experiment the US Office of Naval Research Five-Octave Research Array (FORA) was towed in various geometries making recordings of acoustic transmissions from an array of fixed sources, as well as a ship-suspended and ship-towed source. Physics issues include the structure of the convergence zone (CZ) and its dependence upon mesoscale sound speed and bathymetry, the structure of ambient noise, bottom interacting propagation and out-of-plane reverberation. In this paper, a survey of the recordings will be presented. Broadband Adaptive Beamforming techniques are applied to the array data. Direct comparison of measurements with high-fidelity broadband Parabolic Equation modelling will be presented. Much of the observed phenomenon, such as Transmission Loss (TL), Doppler spread, temporal coherence length and bottom bounce levels are well reproduced by the model. Physics issues that are not included in the modelling will be discussed – internal wave scattering, bottom roughness and out-of-plane propagation.
Observed sound speed structure during the Phil Sea 2009-2011 field years
Authors: Colosi John , Dushaw Brian , Van Uffelen Lora , Cornuelle Bruce , Dzieciuch Matthew , Worcester Peter , Ramp Steve , Bahr Fred
Published: April 2012

From April 2010 to April 2011, 6 moorings equipped with temperature (T), conductivity (C), and pressure (P) sensors along with ADCP's observed oceanic variability in support of concurrent acoustic measurements between the moorings. In addition, for the month of April in 2009, two moorings monitored ocean conditions for a pilot study. During these periods energetic internal waves and tides, as well as eddies were observed thus creating an inhomogeneous, anisotropic, and rapidly changing acoustical environment. Some moorings possessed high precision T, C, and P records capable of resolving intrusive structures sometimes termed spice. In this talk statistical and deterministic metrics will be used to characterize the various dynamical sources of sound speed variability that were observed.
Acoustic seagliders in the Philippine Sea: first steps towards moving-receiver tomography
Authors: Van Uffelen Lora , Nosal Eva-Marie , Howe Bruce , Carter Glenn , Worcester Peter , Dzieciuch Matthew
Published: April 2012

Four Seagliders equipped with Acoustic Recorder Systems (ARS) received transmissions from moored, swept frequency (~200-300 Hz) acoustic sources as part of the ONR-sponsored North Pacific Acoustic Laboratory PhilSea10 Experiment. The gliders transited between the mooring sites from November 2010 until March 2011, diving between the surface and 1000-m depth and providing acoustic receptions at many ranges and depths with respect to the moored sources. The Seagliders utilized GPS positioning at the surface, but were underwater for up to 8 hours at a time, sometimes traveling several kilometers during a single dive. The precision to which the gliders can be located while underwater will be explored, based on acoustic arrivals from five moored sources, to resolve the fundamental ambiguity between position and sound speed. The ultimate goal is to use the Seagliders as additional acoustic tomographic receivers, thereby multiplying the number of acoustic paths in the tomography network.
Quantifying the mesoscale variability in the western subtropical countercurrent (STCC) and its impact on acoustic propagation
Authors: Ramp Steven , Colosi John , Worcester Peter , Bahr Fred
Published: April 2012

During spring 2010 to spring 2011, the acoustics community deployed an impressive star-shaped moored array in the Philippine Sea to study acoustic propagation in deep water and its relationship to the oceanographic variability at a wide range of space and time scales. In addition to the acoustics instrumentation, six of the moorings spaced from 200-650 km apart were densely instrumented with velocity (u, v), Temperature (T), Conductivity (C), and Pressure (P) sensors making them ideally suited to study the mesoscale ocean circulation as well. Previous work has shown that the preferred baroclinic eddy length scale in the western STCC is order 350 km with most eddies propagating westward. These new observations will allow estimation of the vertical structure of the eddies, their propagation speed, their kinetic and available potential energy, and their dynamic stability. This improved view of the STCC eddies will be shared with the acoustics team for use in quantifying the impacts of the eddy variability on the acoustic propagation.
Correlating measured oceanographic and acoustic variability toward understanding uncertainty transfer
Authors: Becker Kyle M. , Osler John C. , Jiang Yong-Min , Bissinger Brett E. , Pecknold Sean
Published: April 2012

The Recognized Environmental Picture experiment 2011 (REP11) was conducted to support research in the areas of battlespace characterization, quantifying uncertainty, and decision support. By integrating results from these three areas, the goal is to incorporate physics based uncertainty transfer in models driving decision support tools. Generically, this is accomplished by parameterizing the environment according to need and providing the best knowledge available for each parameter including uncertainty. Experimentally, the research requires information on both the input and output sides of acoustic propagation models used for tactical prediction or decision aids. This talk describes an experimental effort to contemporaneously measure both oceanographic and acoustic quantities over a wide range of spatio-temporal scales using a combination of mobile, autonomous, and fixed assets. By measuring these quantities over the course of several days and repeating set geometries, many realizations of the oceanographic and acoustic fields were obtained. These data will be examined with respect to correlations between observed variability in the environment and variability in the measured acoustic fields.
Influence of mesoscale eddies and frontal zones on sound propagation at the Northwest Pacific Ocean
Authors: Akulichev V. A. , Bugaeva L. K. , Morgunov Yu. N. , Solovjev A. A.
Published: April 2012

The results of sound propagation through the warm mesoscale eddy in the region of Kuroshio at the Northwest Pacific are presented. The eddy core lies at point about 39° N, 149° E. Horizontal size of eddy was about 350 km, vertical size was more than 600 m. Continuous acoustic signals at the frequencies 232 Hz and 696 Hz were emitted by the sources towed at the depth of 100 m. Signals were received using a drifting system fitted with hydrophones. The results of experimental researches of sound propagation along the traces crossing subarctic frontal zones separating the cold subarctic and warm subtropical waters are submitted too. Reception system was located at a shelf zone near a peninsula Kamchatka at the depth about of 100 m. These traces extended to the distance 2100 km. It is shown that eddies and frontal zones result to the changes of acoustic signal levels. The experimental results were compared with the calculations of acoustic field.
The effects of uncertain environment parameters on sonar operation range in shallow water
Authors: Wang Wenbo , Li Shuqiu , Sun Guiqing , Huang Haining , Zhang Chunhua , Liu Jiyuan , Yin Li
Published: April 2012

Traditional sonar detection performance prediction is based deterministic prediction method, which does not take the impact of uncertain environmental parameters on transmission loss into consideration. Taking passive sonar detection as example, the farthest operation range is certainly unique for fixed frequency, of course, SL, NL, DI and DT are all well known. In this paper, a probabilistic prediction method is proposed in which transmission loss is subject to a probability distribution even for fixed frequency and range. An acoustic field modeling and numeric calculation framework is raised to fill the gap between underwater physics and signal analysis. For simple physical model depicting an infinite half-space consisting of two fluid layers (water and sediment), calculation results indicate that transmission loss is subject to gamma distribution due to roughness at the boundaries and sound speed fluctuation. In the end, some potential applicable prospects of this new acoustic field prediction method are discussed.
Frequency and angle spreading due to rough interface scattering
Authors: Clark Cathy Ann
Published: April 2012

A narrow band passive sonar system sensing propagation of acoustic energy reflected from the ocean bottom in shallow water incurs detection losses due to frequency and angle limitations of the processor and receiving array. These losses are expressible as ratios of integrals of a suitably defined bottom scattering function. This talk presents a modeling approach which uses propagation calculations and a tangent plane approximation to the Helmholtz scattering integral at planes within a layered bottom sediment to analyze sensitivities of the spreading problem and to predict system losses. Model results for a few hypothetical but representative sonar systems will be presented.
The sea surface directional wave spectrum and forward scattering from the sea surface
Authors: Dahl Peter H. , Dall'Osto David R. , Plant William J.
Published: April 2012

An influence of the directional wave spectrum on acoustic forward scattering from the sea surface is difficult to measure. Here we present results of an experiment to measure vertical spatial coherence from an acoustic path interacting once with the sea surface at two different angles with respect to the wave direction. The measurements were part of the Shallow-Water 2006 program that took place off the coast of New Jersey in August 2006. An acoustic source was deployed at depth 40 m, and signals were recorded on a moored receiving system consisting of two, 1.4 m long vertical line arrays centered at depths 25 and 50 m. Measurements were made over four source-receiver bearing angles separated by 90°, during which sea surface conditions remained stable and characterized by an rms waveheight of 0.17 m and a mixed swell, and wind-wave field originating from different directions. The measurements show a statistically significant difference depending on source-receiver bearing when the acoustic frequency is less than about 10 kHz; a result not observed at higher frequencies. This paper will present field observations along with modeling based on a rough surface parabolic wave equation utilizing synthetic sea surfaces. [Research supported by ONR Ocean Acoustics].
Using synthesised musical stimuli to measure room impulse responses in occupied spaces
Authors: Li Francis
Published: April 2012

Since Sabine instigated objective parameters a century ago, the advance of room acoustics has been centred around measurement findings. Room impulse responses are of particular importance: nowadays, measurements typically start from impulse responses, individual acoustic parameters are then derived. With existing methods, noisy signals intolerable to audience are employed as stimuli to obtain the impulse responses. Consequently, occupied measurements are rarely carried out. Unoccupied measurements are unreliable and problematic, because they do not accurately represent the acoustic profile under in-use conditions. This paper presents a method that utilises “presto-chirps”, short chirps centred on musical notes in an equal temperament scale, to synthesise musical notes. The harmonics might be added by the Volterra kernel convolution, if richer tones are preferred. These musical notes are used to compose synthesised music as test stimuli. Room impulse responses are deconvolved from received signals in musical note specified sub-bands. Following energy normalisation and superposition broadband impulse responses are obtained. The use of musical stimuli facilitates occupied measurements. The purpose-defined presto-chirp enables the measurement to be completed in a relatively short duration, mitigating time variance problems.
How the design of a balcony affects the acoustics in an auditorium?
Authors: Cheung L.Y. , Tang S.K.
Published: April 2012

A 3D-simulation for improving the acoustics in an auditorium was done using room acoustic software, Odeon. The software provides the sound field inside the hall and thus the sound propagation physics was studied. The 3D computer model was done based on an existing auditorium of over 1000 seats. Further simulations have been done by removing the balcony and changing it's the geometry. The effect of different balcony geometry on the sound quality inside the hall was estimated and compared. Apart from reverberant time, the effects on energy ratios and other parameters from simulation results were studied. [L. Y. Cheung is supported by the Hong Kong Polytechnic University.]
Acoustic re-radiation of structurally coupled instruments by stage floors and orchestra risers
Authors: Abercrombie Clemeth L. , Brooks Todd L. , Doria Damian J. , Nakajima Tateo
Published: April 2012

The role that structural vibration plays on concert hall stage floors is a point of continous discussion in several lines of research. It is often discussed, if only briefly, in research relating to the perception of warmth in performance spaces, low-frequency sound propagation, and the musician's acoustic environment. Three effects have been researched: acoustic absorption, acoustic reradiation of structurally coupled instruments, and perceptible tactile stimulation. New measurements have been conducted to explore the role of reradiation by wood stage floor constructions and orchestra risers in two recently opened concert halls. Results of these measurements will be presented and reviewed in the context of previous research. Implications for design of musical environments will be discussed.
Effects of periodically arranged absorptive materials on acoustic potential energy in rectangular rooms
Authors: Liu Hao , Li Xiaodong
Published: April 2012

A modal analysis method is applied to compute the acoustic potential energy of a three-dimensional rectangular room, where sound absorptive materials are periodically arranged on the boundaries of the rectangular room. This paper studies the influence of two parameters, including the frequency of the sound source and the number of absorptive material strips, on the acoustic potential energy in detail. This study reveals that both of the two parameters have notable effects on the coupling behavior of room modes. A main result of this paper is that using a periodic arrangement of absorptive materials can be more efficient than totally covering of absorptive materials on corresponding surface in reducing acoustic potential energy under certain conditions. The coupling behavior of room modes can well explain why excess potential energy reduction can be achieved by using periodically arranged absorptive materials.
Acoustic design of the Philharmonic Hall in the Shanghai Oriental Art Center
Authors: Wang Jingbo , Zhang Kuisheng
Published: April 2012

The Shanghai Oriental Art Center opened officially on July. 2005 is one of the largest performance art centers in the domestic. It mainly consists of the 2000 seats philharmonic hall, the 1100 seats opera house and the 300 seats chamber music hall, and several rehearsal facilities. It has been become one of the most important landmark buildings in Shanghai as well in PuDong new district. In this paper it is mainly elucidated the features of the architectural acoustics design of the 2000-seat philharmonic hall, the largest specially designed for music performance venue. It is also covered the objective acoustical measurement results and the subjective acoustics evaluation from all circles after opening.
Estimating the biosonar detection range of mesopelagic patches by spinner dolphins
Authors: Au Whitlow , Lammers Marc , Jung Jokob
Published: April 2012

Spinner dolphins (Stenella longirostris) in the near-shore waters of the Hawaiian islands forage on the mesopelagic boundary community (mbc) of organisms consisting of myctophids, mid-water shrimp and small squids. They forage at night and supposedly in a coordinated fashion and in groups between 16 and 24 animals that are divided into pairs. In the search phase of the foraging process, the dolphins are thought to be spaced in a V-shape formation with the tip of the “V” at the deepest depth, and swim parallel to shore hunting for patches of prey that they can encircle and herd into a tight three-dimensional patch. A profiler housing a broadband echo-ranger that projected dolphin-like biosonar signals was used to measure the target strength of the mbc based on a dolphin's integration window of 264 μs. The bottlenose dolphin, Tursiops truncatus, was used as a proxy to estimate the biosonar detection ranges of Stenella longirostris searching for mbc patches because only limited acoustic research has been performed with spinner dolphins. Using the sonar equation, the biosonar threshold detection range of spinner dolphins was estimated to be approximately 50 to 64 m, more than sufficient range for the animals to formulate their prey herding behavior.
Evolutionary convergence and divergence in bat and toothed whale biosonars
Authors: Madsen Peter Teglberg , Surlykke Annemarie
Published: April 2012

Bats and toothed whales have independently evolved the capability to use echolocation to locate, track and capture prey in a 3-dimensional world of darkness in the night sky or at 1000 meters depth. Despite a very distant common ancestor and the vastly different acoustical properties of air and water, bats and toothed whales use a surprisingly similar ultrasonic frequency range from 15 to 200 kHz for echolocation. In this talk we use recent technical advances in field studies to address and compare the acoustic behavior of bats and toothed whales in the wild. We show that both bats and toothed whales switch to high repetition rate buzzing for prey capture, but that bats capture prey after and toothed whales during buzzing. Bats face a much higher absorption and lower impedance in air by which they have prey detection distances that are between 1 and 2 orders of magnitude shorter than those of toothed whales while moving forward at speeds that are 2-3 times higher. That implies that bats have little time and hence potential for prey discrimination in the wild whereas toothed whales have many seconds between detection/discrimination and the time of capture.
Shandong University—Virginia Tech Biosonar Research in China
Authors: Müller Rolf
Published: April 2012

China is home to a diverse and in many places abundant bat fauna. Among the most diverse and prominent bat families in the country are the horseshoe bats (Rhinolophidae) which also have one of the most specialized and capable sonar systems found in nature. Biosonar research at the Shandong University - Virginia Tech International Laboratory seeks to understand the capabilities and the diverse adaptations in the sonar systems of Chinese bats. A common thread of this research is the analysis of the natural variability in biosonar solutions. For example, the International Laboratory has been compiling a digital database of the noseleaves and outer ear shapes of bats from China and neighboring regions. Current research explores biological adaptation pattern in these shapes and their acoustic properties. Other research explores sound production across different species of Chinese bats. The International Laboratory also conducts behavioral experiments, in particular with horseshoe bats. This research has characterized novel dynamic features on the emission as well as on the reception side of the horseshoe bats' biosonar system. The International Laboratory collaborates with a sister lab at Virginia Tech (GLOBES) on the engineering analysis of the biosonar properties it discovers as well as the development of bioinspired devices.
Large reconfigurable microphone array for transmit beam pattern measurements of echolocating bats
Authors: Gaudette Jason E. , Kloepper Laura N. , Simmons James A.
Published: April 2012

Measurements of the transmit beam patterns in bats have previously been limited to a single cross-sectional plane or averaged over multiple in-flight approaches with sparse microphone arrays. No high-resolution measurements have been published to date of individual transmitted beams jointly in azimuth and elevation. Toward this goal, a high density microphone array was designed and constructed using low-cost ultrasonic microphones and custom electronic circuitry. The planar array is 1.83 meters wide by 1.42 meters tall with sensors positioned on a 2.54 cm square grid. The system can record up to 228 channels simultaneously at a 500 kHz sampling rate. Big brown bats (Eptesicus fuscus) were trained to echolocate pairs of virtual targets in a two-alternative forced choice discrimination task while their signals were being recorded by the array. Visualizations of the beam patterns during the task will be presented along with some advanced signal processing techniques used in the analysis. [funded by ONR and NUWC, Division Newport]
Expression of the gap junction protein connexin-36 in the adult big brown bat cochlear nucleus may be involved in temporally precise biosonar processing
Authors: Wheeler Alyssa , Veltri Carolina , Flores Victoria , Simmons Andrea , Simmons James
Published: April 2012

The big brown bat uses biosonar to orient, navigate, and forage. Successful prey capture requires sonar emissions and returning echoes to be encoded and compared in the central auditory system with precision. Behavioral experiments show that E. fuscus can discriminate echo delay, relative timing of harmonics, and echo phase on the order of 3μs or less. The neurobiological specializations underlying this perceptual acuity remain elusive. New evidence shows that principal cells in the bat's cochlear nucleus (CN) express the neuronal gap junction protein connexin-36. During early postnatal development, connexin-36 expression is seen throughout the AVCN and PVCN of both big brown bats and mice. In adult bats, but not mice, cx36 expression is restricted to a specific population of cells in the ventral AVCN. The retention of cx36 in a discrete population of cells in the adult bat CN suggests that electrical transmission could be involved in processing echolocation sounds with temporal accuracy. Support: NSF grant 0843522 and ONR grant N00014-09-1-0691 to James Simmons.
A preliminary study of ultrasound blood imaging in the common carotid artery of stroke patients
Authors: Bok Tae-Hoon , Kong Qi , Oh Yun Hee , Lee Jang Jin , Kim Joong Goo , Choi Jay Chol , Paeng Dong-Guk
Published: April 2012

Blood echogenicity is changed by red blood cell aggregation due to hemodynamic and hematological factors depending on a person. A stroke is known as a cerebrovascular accident due to lack of the blood flow. Hence, an ultrasound blood imaging could be the preliminary diagnosis for the stroke patient. In this paper, ultrasound images were acquired from the common carotid artery of stroke patients and the control group by the ultrasound imaging system (Voluson e, GE Healthcare, USA). The numbers of subject were 6 stroke patients and 5 healthy people for the control group, and their ages were 67±17 and 68±3 years old, respectively. The average of blood echogenicity of the stroke patients (54±8) was lower than that of the control group (96±8). The amplitudes of the cycle variation of blood echogenicity were similar for both of the stroke patient (18±6) and the control group (23±6). The preliminary experimental results showed the statistical difference of blood echogenicity between the stroke patients and the control group, and the data would be continuously collected from more volunteers (~20 people for each group) and discuss the data in the conference. [Work supported by NRF-2011-0017984.]
Body surface scanner for the abdominal sound speed tomographic imaging
Authors: Yamada Akira , Sasaki Kensuke , Yokoyama Toshihiko
Published: April 2012

The ultrasound tomography has been studied for the reconstruction of the abdominal sound speed image to measure the visceral fat area. The method is based on the travel time observations of the sound waves transmitted through the abdominal medium. In the present study, aiming to realize the method as a clinically available equipment, body surface scanner machinery was developed keeping good contact between a transducer and a human abdominal body surface. To-and-fro movement scanning equipment including the attachment of the elastic coupling gel hemisphere in front of the transducer surface was installed. The optimum pushing status was controlled by monitoring the variation of the received sound wave amplitude. They were in stable over the wide pushing distance region, regardless of the contact surface angle. It was shown that measured precision of the travel time were good enough to discriminate the difference of the sound speed between the fat and protein regions in the human abdominal region.
Development of an ultrasound beamforming research platform based on SonixRP system
Authors: Chen Xin , Zhou Ting , Chen Siping , Wang Tianfu
Published: April 2012

The raw pre-beamforming data are necessary for the study of ultrasound imaging beamforming algorithm. However, the raw data are not accessible for most of the commercial ultrasound scanner. Therefore, most researches have to depend on software simulation. The purpose of this paper was to develop an open platform for the research of ultrasound beamforming. This platform utilized the SonixRP system to obtain the raw pre-beamforming data with great flexibility. The essential imaging parameters and scan sequence can be defined through a user-friendly GUI. Furthermore, a new adaptive beamforming algorithm was proposed and verified on the platform. The results showed that the algorithm can improve the image quality with better enhancement and lateral resolution while compared the conventional DAS algorithm. Acknowledgements: This work is supported by the National Natural Science Foundation of China (81000637, 61031003).
The temperature dependent thermal properties of ex vivo porcine liver tissue heated from 20°C to 90°C
Authors: Choi Min Joo , Guntur Sitaramanjaneya Reddy , Lee Kang IL , Paeng Dong Guk , Coleman Andrew
Published: April 2012

Thermotherapy uses a heat source which raises temperatures in a target tissue, and the temperature rise depends on the thermal properties of a tissue. Little is known about the temperature dependent thermal properties of a tissue, which prevents an accurate prediction of the temperature distribution of a target tissue that is undergoing thermotherapy. The present study reports the key thermal parameters (specific heat capacity, thermal conductivity and heat diffusivity) that was measured on ex-vivo porcine liver while being heated from 20° C to 90° C. The results show that all the thermal parameters resulted in the plots with asymmetrical quasi-parabolic curves with temperature, being convex downward with their minima at the turning temperature of 35-40° C. The largest change was observed for a thermal conductivity, which decreased by 9.6% from its initial value (at 20° C) at the turning temperature (35° C) and rose by 45% at 90° C from its minimum (at 35° C). The minima were 3.567 mJ/(m3.K) regarding the specific heat capacity, 0.520 W/(m.K) regarding the thermal conductivity, and 0.141 mm2/s regarding the thermal diffusivity. The minimum at the turning temperature was unique and is suggested to be taken as a characteristic value of the thermal parameter of the tissue. The study indicates that the key thermal parameters varied largely with temperature, which resulted in having a substantial influence on the temperature distribution of the tissue undergoing thermotherapy. Keywords: thermal properties, ex-vivo porcine liver, temperature, specific heat capacity, thermal conductivity, thermal diffusivity, thermotherapy
High-intensity focused ultrasound heating of large tissue region enhanced by cavitation bubbles at multiple focal spots
Authors: Yoshizawa Shin , Nakamura Kotaro , Asai Ayumu , Yasuda Jun , Umemura Shin-ichiro
Published: April 2012

High-intensity focused ultrasound (HIFU) causes selective tissue necrosis through heating and is used for a noninvasive treatment of cancer therapy. However, it has a problem of a long treatment time for a large tumor. To improve the throughput of the treatment, the development of a highly efficient method is needed. It is known that cavitation bubbles enhance the heating effect of ultrasound during ultrasonic irradiation because the increase in the energy dissipation is caused by the volumetric oscillation of cavitation bubbles. In this study, cavitation bubbles were generated at multiple spots by changing focal position of high-intensity ultrasound. Immediately after generating the bubbles, the bubbles were exposed to a wide-focused ultrasound which covers all the cavitation sites for the cavitation-enhanced heating in a large region. The behavior of the cavitation bubbles at multiple spots in a tissue-mimicking gel was observed by high-speed photography, and the coagulation performance of the developed sequence was confirmed with an experiment using excised tissue. The results showed high efficacy of the proposed method for to coagulate a large tissue region.
Efficient large-scale ultrasound simulation using the k-space pseudospectral method
Authors: Treeby Bradley E. , Jaros Jiri , Cox Ben T. , Rendell Alistair P.
Published: April 2012

Computational acoustics offers a powerful tool for investigating the interaction between ultrasound waves and the human body. However, in many common ultrasound settings, performing realistic simulations is computationally difficult due to the large size of the tissue volume compared to the size of the acoustic wavelength. This is particularly true in the case of high-intensity focused ultrasound where large diameter transducers are used to tightly focus ultrasound waves, often deep within the tissue. Here, an efficient model for large-scale ultrasound simulation is presented. The model is based on coupled first-order acoustic equations valid for nonlinear wave propagation in heterogeneous media with power law absorption. The equations are discretized using the k-space pseudospectral method and encoded using advanced programming techniques for parallel computer architectures. This allows the efficient simulation of nonlinear ultrasound propagation in three-dimensions over hundreds of wavelengths. Applications to both diagnostic and therapeutic ultrasound are discussed, and the results from several simulation examples are presented.