bluuebunny/crossref_metadata_2025 huggingface dataset:
Reproduction of the sound field from a virtual source inside of loudspeaker arrays
Authors: Choi Jung-Woo , Kim Yang-Hann
Published: April 2012

A sound field reproduction method for providing the auditory illusion of a virtual sound source in front of a loudspeaker array is proposed. The Kirchhoff-Helmholtz integral has been popularly used to reproduce the sound field using loudspeaker arrays, and related theories have shown that the internal sound field from virtual sources outside of the array can be reconstructed. Unlike the virtual-source-outside case, however, perfect reproduction of the virtual source inside is physically not possible because of the wavefront converging towards the location of the virtual source. The converging wavefront is one of the artifacts that always arise with artificial rendering, and the reduction of such artifact is seen as a key to reproduce the virtual source inside. For example, in the field of Wave Field Synthesis(WFS), it has been addressed that a focused source inside can be reproduced by combining time-reversal operator with the 2.5D Rayleigh integral equation. In this work, we propose three kinds of integral equation for the virtual-source-inside problem. The first equation is a generalized three-dimensional formula, and the second one is an approximated form for the far-field monopole arrays. An equation having minimal radiation property to the external field is also derived to realize the room-independent reproduction.
Measurement and analysis of sound radiation patterns of the chinese Ruan and the Yueqin
Authors: Pfeifle Florian
Published: April 2012

The chinese Yueqin and Ruan are among the oldest documented asian string instruments. Both have a long tradition in chinese music and are commonly played in orchestral music, smaller ensembles as well as solo instruments. Eventhough both instruments have similar geometrical features, like a cylindric resonance body made out of wood, they differ in several design aspects like the fixation of the strings or the presence of sound holes. In this work the effect of these differences on the radiated and percieved sound is researched. Both instruments are measured using a 11x11 microphone array. The resulting density plots of the sound radiation over the audible spectrum are compared and analyzed.
Tonal characterisation of a wooden resonance box
Authors: Wang Xiaolin , Shen Anne , Gao Jianbo
Published: April 2012

In acoustic studies of musical string instruments, it is a common practice to identify vibration modes of the instrument resonance box. Usually, when a finite element method is employed, typical shell elements instead of solid elements are used for modelling the box, and its viscous properties are typically not taken into account. Although previous researches have indicated that this does not have much impact on the calculation of vibration modes, questions arise when the characteristics of a tonal signal are to be investigated. The problem with such modelling practice is that when shell elements are used and viscous properties are excluded, can we still effectively distinguish the subtle differences of tonal characteristics among those fine instruments. In this work we examine the effects of using different types of finite elements as well as applying viscoelastic properties of wooden materials on the tonal characteristics of sound radiation. By conducting this research for a simply structured wooden resonance box, we are attempting to answer questions such as whether we can afford to exclude either viscous properties or the use of solid elements or both in the study of tonal characteristics. If this is not permissible, then in what way these properties will affect the tonal characteristics.
Decomposition of moving vehicle noise with dynamic transfer model and acoustic holograph
Authors: Zheng Sifa , Hao Peng , Lian Xiaomin
Published: April 2012

Identifying the moving noise of vehicles is the important step to make the optimal countermeasures. A dynamic transfer path model was proposed to describe the relation between the sources on the vehicle and the test point on the ground.The noise signals both from the vehicle and the pass-by test were simultaneously recorded with a wireless device. The parameters in the dynamic model were estimated, and the results with singular value decomposition and Tikhonov regularization were compared using simulation and experiment. The contribution of the sources was decomposed with the dynamic transfer model and acoustic holograph at any test location. Finally, the proposed method was used to decompose the contributions of the sources in a bus. The results show: the dynamic transfer path analysis could be used to identify each of the noise sources and decompose their contribution in the pass-by test.
An algorithm for artillery noise signal detection and classification in time-domain
Authors: Zhou Yinlong
Published: April 2012

Artillery noise signal can propagate long distance. It's changed greatly in complex weather condition, and becomes difficult to detect. In adding to variety of environment noise and echo signal, the truth is that artillery noise signal becomes more difficult to detect and classify. The classic and modern spectral estimation are used to process these problems frequently, while these methods will lose detail of signal are not suitable, because of the signal is non-stationary. Wavelet analysis is likely the proper method to process non-stationary signal, while spending of computation is worth of considering for each algorithm. An algorithm for artillery noise signal detection and classification in time-domain is proposed in this paper. By processing in time-domain, we can save spending of computation. By use of short-term zero-crossing rate Zs and short-term amplitude As, we won't loss detail of signal; By use of proposed “period-amplitude” Ps in paper, we can detect artillery noise signal that propagating from far away; By use of dynamic threshold and array signal processing, we can suppress effect of environment noise and echo signal. By use of sample libraries of definite physical definition in time-domain, we can classify clearly.
Design-optimization of a broadband phased microphone array for aeroacoustic applications
Authors: Reger Robert , Zawodny Nikolas , Pascioni Kyle , Wetzel Drew , Liu Fei , Cattafesta Lou
Published: April 2012

Phased microphone arrays are commonly used in acoustic beamforming applications. While numerous beamforming algorithms have been proposed to alleviate deficiencies of the delay-and-sum approach, few studies have focused on the array design itself. In aeroacoustic applications, the most common designs are based on circularly symmetric spiral arrays devised by Underbrink (1995). The design of an array using such a method is complex and tedious due to the numerous design variables and corresponding trade-offs between resolution, sidelobe suppression, size, and cost. In this paper, a systematic design-optimization approach is described that offers several objective functions and constraints. Candidate arrays for use in the University of Florida Aeroacoustic Flow Facility (UFAFF) are designed for a broadband frequency range of 1 to 80 kHz. The results of these different cases will be compared to those of an existing array design currently used in the UFAFF. An optimized design is selected and fabricated for characterization and testing in the UFAFF. These results and comparison are described.
Source localization using a double three-dimensional intensity array
Authors: Cho Sung-Kyu , Ih Jeong-Guon
Published: April 2012

The precision of source localization methods using an array of multiple microphones depends on the number of microphones and spacing, i.e., it requires many microphones, small spacing and large aperture. To overcome the demerit in size, cost and data processing time, a double-module array system was suggested, of which a three-dimensional intensity array consists of a module. A three-dimensional intensity vector indicating the bearing angle was estimated using a set of four microphones arranged in a tetrahedral shape. Because a microphone in the apex was used in common for two modules along with the compactness of tetrahedron, number of microphones and size could be reduced. To cover a wide frequency range, two modules had different microphone spacing to minimize the low frequency phase error and high frequency finite difference error. Three-dimensional intensity was calculated by using the Taylor series expansion. For a double-module array having 16 and 80 mm in array spacing, simulations, assuming an anechoic condition, were conducted to test performances of angle detection varying bearing angle of source location, which was 1.3 m apart from the detection module. Average error of all bearing angles was less than 2o for 270-7800 Hz. (Partially supported by BK 21 project)
Development of long-term data acquisition system of noise exposure and personal behavior for analysis of health risk: Preliminary studies
Authors: Fujimoto Kazutoshi , Imaizumi Hiroyuki , Anai Ken , Hiraguri Yasuhiro
Published: April 2012

To investigate relationship between individual noise exposure and the effect on health, firstly we have designed a measuring equipment because commercially-available noise exposure meter adopts the averaging times of a few minutes that are longer for our purpose. Requirements of the equipment we focus on are to measure (1) intermittent characteristic of noise that include the maximum level, the number of event, and level difference between background and target noises for sleep disturbance, and (2) equivalent continuous A-weighted sound pressure levels during 24h for physiological effect. Environmental condition especially in nighttime and position where people are exposed to noise are also important parameters to be taken into consideration. In addition to the noise exposure meter, the measuring equipment developed includes thermohygrometer, illuminator and smartphone. We pursue portability and simplicity throughout the equipment. We suppose that subjects put on the noise exposure meter and the smartphone on their waist in daytime. Accuracy of the noise exposure levels at the waist is examined by simultaneous measurement near the ear at various scenes in our daily life. Long-term measurement of individual noise exposure that several subjects participate in is performed to verify the equipment. This report presents the results of preliminary measurements.
Noise-reducing asphalt rubber surfaces in China
Authors: Way George , Sousa Jorge , Cao Rongji , Biligiri Krishna
Published: April 2012

Beginning in about 2004 the state-of-the-art and practice of asphalt rubber (AR) surfaces as used and applied in the United States (US) to reduce traffic noise was presented in China. AR surfaces have been used in US for many years to reduce the traffic noise. The AR surfaces can be applied as the final wearing course on concrete or asphalt pavements. Both the US states of California and Arizona and others have successfully employed thin wearing courses (12.5 to 40 mm) of AR to reduce highway noise. Following this early exposure to the AR technology, China began to experiment and later use AR to reduce noise, as well as to provide a durable and good quality skid resistant wearing course. This paper reports on the progress of use of AR in China and the noise data from various surfaces in China. These surfaces include Stone Mastic Asphalt, Polymer Asphalt, Asphalt Rubber Asphalt Concrete and Asphalt Rubber Open Graded Friction Course.
Innovative low noise road pavement materials studied in Portugal
Authors: Freitas Elisabete , Oliveira Joel , Machado Pedro
Published: April 2012

This paper deals with materials not conventionally used in road layers but widely used in the building construction to reduce noise. These materials are expanded clay aggregates and cork granulates. The former is characterized by a high porosity and therefore used in a surface course to partially absorb the noise and the latter is characterized by a resilient behaviour and thus used in the binder course, to cushion the vibrations originated at the top of the pavement on the vehicles movements. Their mechanical and acoustic behaviour must be proved in laboratory before construction in real scale and surface characteristics such as skid resistance must keep a high level along time. This paper addresses particularly these issues. The first results are very encouraging. When compared to equivalent conventional mixtures, their mechanical properties obtained from laboratory tests have improved. Acoustic properties, such as noise absorption, and acoustic related properties, such as those extracted from mechanical impedance tests, have also indicated a superior performance.
Ultra long life low noise porous asphalt
Authors: Alabaster D. , Herrington P.R. , Waters J.
Published: April 2012

This New Zealand laboratory study and field trial forms part of a larger collaborative research programme conducted under the auspices of the OECD/ECMT (European Conference of Ministers of Transport) Joint Transport Research Centre, focused on the economic evaluation of long-life pavements. The aim of the research was to investigate the potential of epoxy-modified asphalt as a low-maintenance long-life (>30 years) low noise surfacing material. The New Zealand Transport Agency's contribution to the research focused on the potential benefits of epoxy-modified open-graded porous asphalt (OGPA). Investigations into the cohesive properties and oxidation resistance of an acid-cured, epoxy-modified OGPA were undertaken, and an associated field trial constructed on State Highway 1 in Christchurch in December 2007. Results from the Cantabro Test at 10° C indicated that the cohesive properties of the oxidised epoxy OGPA were markedly superior to those of conventional OGPA. On the basis of the Cantabro test results, lifetimes of up 144 years were estimated for an increase in cost of up to 2.3 times that of conventional OGPA. Similarly, the fatigue life of oxidised epoxy OGPA was found to be more than 25 times that of the control. Experiments were also conducted with epoxy modified bitumen diluted with up to 75% standard 80–100 penetration grade bitumen, as a possible means of reducing costs. OGPA made with the 75% diluted material had an estimated life of up to 93 years for 1.3 times the cost of conventional OGPA. The fatigue lives of the oxidised diluted OGPA mixes were similar to that of the control. An initial CAPTIF trial and a later field trial demonstrated that full-scale manufacture and surfacing construction with epoxy OGPA, could be easily undertaken without any significant modification to plant or operating procedures. A road trial to evaluate (undiluted) epoxy OGPA sections with 20% and 30% air voids was constructed and initial noise monitoring using the statistical pass by method has produced good results. The trial has been in place for almost 4 years and is performing well.
Which is a better metric - road or air temperature - in assessing temperature effects on tyre/road noise?
Authors: Hung Wing-tat , Lam Yat-ken , Leung Randolph Chi-kin , Ng Chung-fai
Published: April 2012

The temperature effect on tyre/road noise level has been vigorously studied recently. Recommendation of temperature correction is being made in the draft ISO 11819-2 for tyre/road noise measurement. Air temperature is used as the basic metric for temperature. However, road surface temperature appears to be a more direct metric and now is equally easy to measure as air temperature. To assess which is a better temperature metric, CPX tyre/road measurements with a pair of Standard Reference Test Tyre (Uniroyal Tigerpaw 225/60-R16) running on a number of stone mastic asphalt and polymer modified porous asphalt road surfaces at reference speed 50 km/h were made in day and night time. Instantaneous air and road surface temperatures were also recorded during the measurements. Results show that tyre/road noise decreases as temperatures increase. The correlations between the noise level and air or road surface temperatures varied between road sections. The temperature coefficients derived using the road temperature have smaller variation then that estimated using the air temperature.
Nonlinear bubble dynamics of cavitation
Authors: An Yu
Published: April 2012

A theoretical framework for studying cavitation dynamics is revived. It consists of a nonlinear sound wave equation in an acoustic cavitation environment together with the bubble motion equation. The nonlinear sound wave equation considers time delayed bubble-bubble interaction. For cavitation clouds generated in a standing sound wave driven by an ultrasonic horn, the equations are numerically solved under an approximation. It is found that the number density of bubble is a key parameter in describing the bubble dynamics of cavitation. Adjusting this parameter, our calculation may produce the chaotic acoustic pressure and various different forms of bubble motion in cavitation cloud, and can qualitatively reproduce experimentally observed phenomena.
Acoustic, thermal and sonoluminescence investigation of enhanced cavitation of flowing polymer- and lipid-shelled microbubbles during focused ultrasound exposures
Authors: Zhang Siyuan , Qiao Yangzi , Wan Mingxi
Published: April 2012

Our previous work has investigated spatial-temporal dynamics of cavitation during focused ultrasound (FU) exposures using acoustic cavitation detection and high-speed photography. In this paper, acoustic, thermal and sonoluminescence investigation of enhanced cavitation of flowing polymer- and lipid-shelled microbubbles (MBs) during FU exposures were exposed as the two types of shelled MBs and pure controls flowing through a vessel in the phantom with varying flow velocities at different acoustic power levels. Vibration characteristics of two shelled MBs and the effects of acoustic pressure threshold for destruction of the two shelled MBs on the intensity and spatial distribution of sonoluminescence and sonochemiluminescence were investigated using an intensified charge coupled device camera. The inertial cavitation dose (ICD), sonoluminescence intensity and temperature for the lipid-shelled MBs were higher than those for the polymer-shelled MBs, which were both higher than pure controls. Temperature around the vessel initially increased with increasing flow velocities of MBs, followed by a decrease of the peak temperatures with increasing flow velocities when the velocity was much higher. Meanwhile, ICD showed a trend of increases with increasing flow velocity. Thermal lesion appeared around the vessel as MBs flowing through the vessel, at which lesion was not observed originally without MBs.
Trapping of microorganism using cylindrical standing ultrasound waves and its application to water purification
Authors: Hwang Hae-Rang , Cao Yonggang , Kim Jungsoon , Kim Moojoon , Ha Kang-Lyeol
Published: April 2012

In biological fields, it is known that the ultrasound is useful for trapping of biological cells or microorganism. Recently, several experimental results of micro-particle trapping by acoustic standing wave fields which are formed by plane waves have been reported. In this study, we confirm that the standing waves by a cylindrical ultrasonic transducer can trap and aggregate the microorganism such as green algae, chlorella, etc. Those microorganism were trapped at specific positions determined by acoustic pressure distribution, and the density of aggregation is increased according to the lapse time after the transducer operating. The dense colony of microorganism is easily filtered out by a sieve. A water purification system using this phenomenon was designed and the efficiency was verified by considering the density change of the microorganism after the ultrasonic treatment. Consequently, it is shown that the standing wave in a cylindrical transducer can be applied to water purification.
A study of the ultrasonic preparation of neodymium doped zinc oxide nanoparticles in room temperature ionic liquid
Authors: Yang Yuetao , Yang Hao , Zhang Shuyi , Liu Xiaojun
Published: April 2012

The sonochemical process has been proved to be a useful technique for generating various nanostructured materials. The physical and chemical effects of cavitation are highly dependent on the contents of the collapsing bubble and hence on the choice of solvent. Recently, room-temperature ionic liquid (RTIL) have been developed to a central point of interest in both academia and industry. RTIL are nonvolatile, non-flammable, and thermally stable solvents. These properties make ionic liquids potentially attractive for use in sonochemical reactions. The application of ultrasound to synthesis nanomaterials in conjunction with ionic liquids, however, has been rarely exploited. In this work, a facile approach has been developed for the preparation of neodymium doped zinc oxide nanopaticles in RTIL via an ultrasonic irradiation. The morphology and properties of the products have been characterized by X-ray diffraction and transmission electron microscopy. A possible mechanism is proposed to explain the formation neodymium doped zinc oxide nanoparticles via ultrasonic irradiation.
Stream segregation of simultaneous harmonic sounds in normal and impaired hearing
Authors: Oxenham Andrew , Micheyl Christophe , Kreft Heather
Published: April 2012

Many everyday situations involve hearing out harmonic sounds, such as voiced speech or musical notes, and following them over time in the presence of other harmonic sounds. Despite decades of research on pitch perception, it remains unclear whether the ability to hear out the pitch of one harmonic sound in the presence of others is limited by peripheral frequency selectivity or by other factors, such as phase-locking to the temporal waveform of sounds. In this study a direct test of the role of frequency selectivity was undertaken by examining the relationship between measures of frequency selectivity and measures of performance in pitch- and melody-discrimination tasks in normal-hearing and hearing-impaired listeners. Preliminary data suggest a relationship between auditory-filter bandwidths and the amount of interference produced by a harmonic-complex masker. However, some aspects of the results indicate that factors other than frequency selectivity also play an important role, particularly in the complex tasks involving melody discrimination. [Work was supported by NIH grant R01DC05216; subject recruitment was facilitated by Starkey Laboratories, Inc.]
The influence of perceptual organisation on an auditory context effect
Authors: Chambers Claire , Akram Sahar , Shamma Shihab , Pressnitzer Daniel
Published: April 2012

Perceptual organization of auditory scenes has a well-documented effect on subjective reports of listeners. Here, we investigated whether it also influenced an auditory context effect based on pitch. Stimuli were complexes of sinusoidal components arranged to produce ambiguous pitch transitions when presented successively. The context effect was established by preceding an ambiguous test pair with tone complexes comprising frequencies between the components of the ambiguous pair, which was found to produce a strong bias on the test [Chambers & Pressnitzer, MidWinter Meeting of the Association for Research in Otolaryngology, 2011]. We first tested whether spatial attention modulated the context effect. Two sequences inducing opposing biases were presented dichotically, followed by an ambiguous monaural test. Listeners were more likely to be biased by the attended context. Then we tested whether figure-ground segregation was required for the context effect. We embedded the context tones in random clouds of pure tones, and varied the temporal coherence between the components of the context stimuli. High coherence produced more detectability of the context and, generally, stronger context effects. Both experiments show that stream segregation of the context sequences strongly influences the resulting bias, for identical physical stimuli. This may provide an additional objective measure of streaming.
A physiologically inspired model of auditory stream segregation based on a temporal coherence analysis
Authors: Christiansen Simon Krogholt , Jepsen Morten Løve , Dau Torsten
Published: April 2012

The ability to perceptually separate acoustic sources and focus one's attention on a single source at a time is essential for our ability to use acoustic information. In this study, a physiologically inspired model of human auditory processing Jepsenetal., 2008 was used as a front end of a model for auditory stream segregation. A temporal coherence analysis Elhilalietal., 2009 was applied at the output of the preprocessing, using the coherence across tonotopic channels to group activity across frequency. Using this approach, the described model is able to quantitatively account for classical streaming phenomena relying on frequency separation and tone presentation rate, such as the temporal coherence boundary and the fission boundary vanNoorden, 1975. The same model also accounts for the perceptual grouping of distant spectral components in the case of synchronous presentation. The most essential components of the front-end and back-end processing in the framework of the presented model are analyzed and future perspectives discussed.
On the measurement of angular-dependent, airborne sound transmission through finite supercritical bars: Further results
Authors: Shaw Matthew D. , Anderson Brian E.
Published: April 2012

A method of measuring the angular dependence of sound transmission through supercritical bars in air is discussed. The coincidence effect occurs in a supercritical bar when the component of the acoustic wave number parallel to the bar matches the bending wave number in the bar. The transmission of sound is at a maximum at the angle where this trace wave number matching occurs. The theory of the coincidence effect is well-defined for unbounded thin plates using plane-wave excitation. An experimental setup has been developed in order to observe the coincidence effect using continuous-wave excitation and phased-array methods through finite bars. Experimental results through a 0.5 mm thick aluminum bar exhibit strong maxima at the predicted coincidence angles, showing that coincidence is observable using continuous waves. Measurements of the coincidence angle at frequencies spanning from the critical frequency up to nearly three times the critical frequency have been made. A curve fit to the frequency dependent measurement of coincidence angles allows one to determine the bending stiffness of a bar of unknown material properties.
The underwater vibration characteristics of double plate with periodic connectors
Authors: Xiaobin Liu , Mengsa Yu
Published: April 2012

Double plate is widely used to isolate the vibration and noise in the air,it needs more research on the underwater application.The vibration model of double plate with periodic connectors was built up.The transmission path of power was analyzed carefully and this analysis revealed the specific frequency and wavenumber selective characteristics of double plate in comparison with the single plate.The incident sound wave and the turbulence have very different frequency and wavenumber's spectrum,this may introduce very interesting usage in the sonar dome which needs consideration of both sound wave and turbulence.
Comparing language experience and task demands in Mandarin tone processing: Neurophysiological evidence
Authors: Yu Yan H. , Shafer Valerie L. , Sussman Elyse , Whalen D. H.
Published: April 2012

Behavioral studies have suggested that speech discrimination can operate at the acoustic/phonetic level at relatively short interstimulus intervals (ISIs<500 ms) because the auditory trace is robust. However, with longer delays (>1500 ms) the short-term memory trace decays, and thus, discrimination must rely on the phonemic information stored in long-term memory (Werker & Logan, 1985). To study the neurophysiology of tone perception, native Mandarin and monolingual English speakers participated in a passive oddball paradigm designed to elicit mismatch negativity (MMN). Event-related potentials were recorded from 65 electrode sites. Two tone-contrast pairs (“easy”: tone 3-tone 1; “hard”: tone 3-tone 2) were presented in bisyllabic nonword contexts in short and long ISI conditions. It is found that Mandarin listeners have similar amplitude MMN evoked by the easy-tone and hard-tone contrasts at both ISIs. English listeners, in contrast, have larger amplitude MMNs to the hard-tone contrast only in the short ISI condition. Further, the English-speaking group also showed a larger N1 peak amplitude in the long ISI condition compared to the short ISI or to Mandarin listeners. The results suggest that language experience and task demands influence speech processing at both the lower sensory (indexed by N1) and higher cognitive (indexed by MMN) levels.
Speech perception development in monolingual and bilingual infants
Authors: Garcia-Sierra Adrian , Ramirez-Esparza Nairan , Kuhl Patricia K.
Published: April 2012

We investigated the relation between language exposure and neural commitment to the phonetic units of language in 11-14 month-old English monolingual (N=22) and English-Spanish bilingual infants (N=22). Our previous work suggested that bilingual infants develop phonetic neural commitment at a different pace than their monolingual peers (Garcia-Sierra et al., 2011). However, interpretation of the bilingual data requires testing a speech contrast that is non-native for both bilinguals and monolinguals. We assessed language exposure using LENA digital recorders. Neural speech discrimination (English, Spanish, Mandarin) was tested using event-related potentials (ERPs) to determine the Mismatch Response (MMR). Both groups showed significant correlations between MMRs and language exposure. However, monolinguals showed negative MMRs and negative correlations between MMR and exposure; bilinguals showed positive MMRs and positive correlations with exposure. Negative MMRs are interpreted as an established commitment to native speech sounds. Positive MMRs are interpreted as an initial ability to discriminate sounds. No correlations were found between Mandarin-MMRs and language exposure. Another phonetic contrast (Hindi), nonnative for both groups, is now being tested in the monolingual and bilingual children. Our results support the view that bilingual and monolingual infants show a different pattern of speech perception development.
Entropy coding for training deep belief networks with imbalanced and unlabeled data
Authors: Berry Jeffrey , Fasel Ian , Fadiga Luciano , Archangeli Diana
Published: April 2012

Training deep belief networks (DBNs) is normally done with large data sets. In this work, the goal is to predict traces of the surface of the tongue in ultrasound images of the mouth during speech. Performance on this task can be dramatically enhanced by pre-training a DBN jointly on human-supplied traces and ultrasound images, then training a modified version of the network to predict traces from ultrasound only. However, hand-tracing the entire dataset of ultrasound images is extremely labor intensive. Moreover, the dataset is highly imbalanced since many images are extremely similar. This work presents a bootstrapping method which takes advantage of this imbalance, iteratively selecting a small subset of images to be hand-traced, then (re)training the DBN, making use of an entropy-based diversity measure for the initial selection. With this approach, a three-fold reduction in human time required to trace an entire dataset with human-level accuracy was achieved.
Voice search optimization using weighted finite-state transducers
Authors: Guo Yuhong , Li Ta , Si Yujing , Pan Jielin , Yan Yonghong
Published: April 2012

Voice search system can provide users with information according to their spoken queries. However, as the most important module in this system, the high word error rate of the automatic speech recognition (ASR) part degrades the whole system's performance. Moreover, the runtime efficiency of the ASR also becomes the bottleneck in the large scale application of voice search. In this paper, an optimized weighted finite-state transducer (WFST) based voice search system is proposed. A weighed parallel silence short-pause model is introduced to reduce both the final transducer size and the word error rate. The WFST network is optimized as well. The experimental results show that, the recognition speed of proposed system outperforms the other recognition system at the equal word error rate and the miracle error rate is also significantly reduced. This work is partially supported by the National Natural Science Foundation of China (No's. 10925419, 90920302, 10874203, 60875014, 61072124, 11074275, 11161140319).
Analysis of sidelobe blanking technique for two-channel speech enhancement
Authors: Jiang Kaiyu , Fu Qiang , Yan Yonghong
Published: April 2012

This paper analyzes the application of Sidelobe Blanking Logic to Two-Channel speech enhancement. We show that several separately proposed Two-Channel post-filtering speech enhancement methods can be viewed as variants of Sidelobe Blanking Logic technique which first arouse in the Radar community around the 1970s. We show that the core mechanism of this kind of technique lies in the two combined target detection measures, that is nonstationarity and Main to Auxiliary ratio. Consequently, the key role played by the detection thresholds is revealed. From this point of view, we show that a well-known two-channel post-filtering method can be improved by adapting the threshold to the main and auxiliary receiver characteristics, and simplified by using a single hard threshold and wiener filtering instead of double thresholds and OM-LSA, without significant performance loss.
Noise reduction for auditory prostheses based on harmonic detection
Authors: Wang Ningyuan , Oxenham Andrew J
Published: April 2012

Difficulty in understanding speech in background noise is one of the most common complaints of hearing-aid and cochlear-implant users. Various noise-reduction and spectral-enhancement algorithms have been designed and tested over the years, often with limited success in terms of improving speech intelligibility. A commonly used method involves spectral subtraction, which is based on the assumption that the noise spectrum can be estimated and the clean speech signal can be extracted by subtracting the noise spectrum from the noisy speech signal. However, recent studies have shown that such methods often result in poorer signal-to-noise ratios in the modulation-spectrum domain, which may explain why little benefit in speech intelligibility has been found. Also, identifying noise in terms of its stationarity runs the risk of misidentification in more stationary signals, such as music. Here a noise reduction algorithm based on harmonic detection and enhancement was explored. Simulation results showed that this algorithm could help suppress noise in both speech and music. Results from perceptual tests will be reported. [Supported in part by Advanced Bionics.]
Large margin gaussian mixture models for discriminative training in language recognition
Authors: Yang Jinchao , Yan Yonghong
Published: April 2012

In this paper, we try to integrate the concept of large margin gaussian mixture models (large margin GMMs) into discriminative training for language recognition. We proposed a new language recognition system (SVM-LM-ModelPushing system) which combines model pushing by large margin GMMs (LM-ModelPushing) with original model pushing by SVM (ModelPushing). Our experiments show that LM-ModelPushing includes the language dependent information. What's more, our experiments show that LM-ModelPushing contains different language dependent information comparing to ModelPushing. Experiment results on 2007 National Institute of Standards and Technology (NIST) language Recognition Evaluation (LRE) databases show SVM-LM-ModelPushing system gains relative improvement in EER of 9.1% and in minDCF of 8.8% comparing to original ModelPushing system in 30-second tasks.
Multi-band OFDM for underwater acoustic communications
Authors: Griffin Robert , Qu Fengzhong , Yang Liuqing
Published: April 2012

For underwater acoustic communications (UAC), the bandwidth is wide compared with the carrier frequency. Because of this fact, the advantages of using multiband OFDM (MB-OFDM) for ultra-wideband communications in terrestrial environments may also apply to UAC scenarios. In this paper, a comparison is made between the use of single-band OFDM and MB-OFDM for UAC. The complexity of each method is shown and experimental results from the WHOI09 undersea trial are presented for both single-band and multiband schemes. From the analysis and experimental results, the validity of treating UAC as ultra-wideband can be determined and the comparative advantages and disadvantages of MB-OFDM versus single-band OFDM for UAC discovered.
Ranging, localization and tracking as functions of underwater acoustic networks
Authors: Rice Joseph
Published: April 2012

Through-water acoustic communications are now enabling distributed underwater networks with fixed and mobile nodes. This paper presents implementations of node-to-node ranging as a by-product of link-layer RTS/CTS handshaking and as an explicit product of ping/echo bidirectional communications. Simultaneous ranging to multiple nodes is accomplished by use of a broadcast ping. Experimental deployments of acoustic networks have demonstrated the use of ranging for purposes of neighbor discovery, network routing optimization, and node localization. These functions are combined to enable the autonomous initialization of large networks deployed in an arbitrary distribution. Acoustic ranging is also shown to enable underwater navigation by a mobile node operating in the domain of a fixed distributed network.
Wave propagation prediction over a thin elastic sediment and rock basement
Authors: Clark Cathy Ann
Published: April 2012

A bottom model which includes compressional and shear wave transmissions and reflections through a sediment layer is utilized to derive a single bottom reflection loss coefficient. When used in conjunction with a normal mode model, the single coefficient is shown to successfully reproduce resonance effects due to shear wave conversion in various sediments. The consolidation of an infinite number of reflections and transmissions is accomplished by formulating an infinite sum of matrices and expressing the result as a convergent series. Comparisons to measured data are presented for a number of underwater environments.
On the acoustics of gas-bearing marine sediment
Authors: Leurer Klaus C. , Brown Colin
Published: April 2012

Gas forms in marine sediments because of the decay of organisms in anoxic conditions abundant in sediments of inhibited water mobility. Its mechanical and thermodynamic properties, e.g., density and compressibility, which are significantly different from those of the pore water and the grain material will lead to a dramatic decrease in the sediment's sound velocity and effective density, as well as the quality factor, whenever even only a few percent of free gas is present in the sediment. A variety of possible spatial distributions of a gaseous phase has been identified, ranging from free spheroidal gas bubbles in the pore space-filling fluid over various “patchy-saturation” scenarios to the displacement of parts of the total saturated sediment matrix, the respective scheme depending on such factors as grain size, sorting, wettability, among others. These different spatial distribution schemes require individually appropriate conceptions for the calculation of the acoustic properties from sediment physical characteristics. A recently proposed acoustic model [JASA 123, pp. 1941-1951, 2008] has been developed to account for the two cases of free gas bubbles in the pore space and for the local displacement of the saturated sediment.
Shear wave speed inversions using scholte wave dispersion
Authors: Potty Gopu R. , Miller James H , Giard Jennifer , McNeese Andrew R. , Wilson Preston S. , Jiang Yong-Min
Published: April 2012

Shear speeds in semi-consolidated and consolidated shallow water sediments can significantly impact compressional wave attenuation and arrival times of acoustic normal modes. In addition, shear properties of sediments are directly related to the strength of the sediments in geotechnical applications. All of these factors emphasize the importance of estimating shear speeds in shallow water sediments. One of the most promising approaches to estimate shear speed is to invert the shear speed profile using the dispersion of interface waves (Scholte waves). The propagation speed and attenuation of the Scholte wave are closely related to shear-wave speed and attenuation over a depth of 1-2 wavelengths into the seabed. Data from the tests conducted in Narragansett Bay and off Block Island in water depths ranging from 10 m to 25 m using the shear measurement system, developed at the University of Rhode Island, will be presented. Combustive Sound Source (CSS) was be used to generate interface waves during these tests. An inversion algorithm to estimate the shear wave speed profile in the sediment will be presented. Estimates of the shear speed will be compared with ground truth data. [Work supported by Office of Naval Research]
Acoustic design of Grand Theatre projects in China
Authors: Kahle Eckhard , Wulfrank Thomas , Jurkiewicz Yann , Katz Brian , Möller Henrik
Published: April 2012

In the People's Republic of China a large number of so-called Grand Theatre projects have recently been completed or are at present being constructed. In addition, other Grand Theatres are still on the drawing boards. These new cultural venues, typically housing multiple auditoria, are dedicated to Chinese and western opera, symphonic music and theatre. The present paper discusses the acoustic design of the Wuxi, Weifang and Jinan Grand Theatres. Due to the stringent fast-track design process, it was considered unpractical to carry out conventional computer modelling studies to inform the design. Novel acoustic design techniques were used for fast optimisation of early reflections in close collaboration with the architects during the early design stages. In the later design stages, full acoustic verification was carried out, often while construction was already underway.
A Note on practical aspect on diffusive reflection in concert halls
Authors: Hidaka Takayuki
Published: April 2012

A number of reports have been recently published about the effect of irregularities, that is, diffusive reflection, on the interior wall of the concert hall. The majority of those reports, however, deal with measurements of the scattering coefficient. And there is only a small number of reports reviewing what size irregularity is actually preferable when a diffusive surface should be taken into account for the interior wall. In this paper, we focus on the actual diffusive surfaces in halls and discuss the acoustic behavioir of those surfaces by numerical analysis. We also address the acoustically recommendable property of the diffusive surface, which is considered to prevent acoustic glare, (Beranek, Concert and Opera Halls, 1996, chap. 10) and discuss its citing actual measurement data.
Visual aspect in concert hall design - recent trend
Authors: Toyota Yasuhisa
Published: April 2012

The visual aspect has become much more important in concert hall design. The New World Symphony opened a new concert hall in Miami in early 2011, expressing a multimedia visual concept where five large walls of the auditorium are used as screens for a multitude of projectors. A flexible layout for both musicians and the audience is enabled by a movable stage and audience areas. Musicians located away from Miami Beach collaborate with resident musicians through the use of the high-speed Internet2 network. Concerts in the Performance Hall are also served simultaneously to an audience outside the building in the adjacent city park with high-definition audio and video. Experimental collaboration between music and visual images is a key function of the building. The acoustics and acoustical design of this “visual” concert hall are discussed.
The calculation of impulse responses in concert halls below 80 Hz
Authors: Ahnert Wolfgang
Published: April 2012

Computer Simulation of room acoustics in large and medium-size venues has become a standard in the acoustic design process. But the Ray or Beam Tracing methods used in all such simulation programs cannot be applied at low frequencies. Here the rules of wave Acoustics must be considered. This work introduces a practical and accurate software-based approach for simulating the acoustic properties of concert and other large halls based on FEM. A detailed approach to obtain complex transfer functions is presented. By means of an inverse FFT impulse responses are obtained and compared with Ray Tracing results. It is shown that the results calculated with FEM extend the fine structure of Ray Tracing results at low frequencies. Also, it is understandable that the FEM simulation software can help to avoid modal phenomena and to place absorbers and diffusers in order to improve the acoustic quality of the hall.
Objective analysis of concert hall design using ISO3382-1
Authors: Barron Mike
Published: April 2012

ISO3382-1 (originally issued in 1997) provides five basic objective measures for assessing concert hall acoustics: reverberation time, Early Decay Time, early-to-late sound index (C80), early lateral fraction and Strength (G) or total sound level. Optimum values for the objective measures have been proposed by several authors. But how much trust can one place in this approach? The author's book Auditorium acoustics and architectural design, 2nd edition, contains 16 case studies of concert halls with both subjective questionnaire ratings and objective measurements. This data can be used to assess the value and validity of these objective measures to offer an answer to the question: how reliable is design according to ISO3382-1, as currently used by many acousticians at the design stage? The analysis in fact uses the further analysis tool involving comparisons of measured levels with revised theory of sound level distribution.
Feasibility study of using macrophages as drug delivery carriers for drug-loaded phase-change droplets
Authors: Yeh Chih-Kuang
Published: April 2012

This study investigated the acoustic droplet vaporization (ADV) of perfluoropentane (PFP) droplets in single droplet-loaded macrophages (DLMs) by insonation with single three-cycle ultrasound pulses. Transient responses of intracellular ADV within a single DLM were observed with synchronous high-speed photography and cavitation detection. Ultrasound B-mode imaging was further applied to demonstrate the contrast enhancement of ADV-generated bubbles from a group of DLMs. The PFP droplets incorporated in a DLM can be liberated from the cell body after being vaporized into gas bubbles. Inertial cavitation can be simultaneously induced at the same time that bubbles appear. The coalescence of bubbles occurring at the onset of vaporization may facilitate gas embolotherapy and ultrasound imaging. Macrophages can be potential carriers transporting PFP droplets to avascular and hypoxic regions in tumors for ultrasound-controlled drug release and ADV-based tumor therapies.