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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
The Journal of the Acoustical Society of Korea
Journal Basic Information
Journal DOI :
The Acoustical Society of Korea
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Volume & Issues
Volume 31, Issue 8 - Nov 2012
Volume 31, Issue 7 - Oct 2012
Volume 31, Issue 6 - Aug 2012
Volume 31, Issue 5 - Jul 2012
Volume 31, Issue 4 - May 2012
Volume 31, Issue 3 - Apr 2012
Volume 31, Issue 2 - Feb 2012
Volume 31, Issue 1 - Jan 2012
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Effect of Diffuser Locations on the Room Acoustical Parameters in 1:25 Scale Model Hall
Kim, Yong-Hee ; Seo, Choon-Ki ; Lee, Hye-Mi ; Jeon, Jin-Yong ;
The Journal of the Acoustical Society of Korea, volume 31, issue 3, 2012, Pages 115~128
DOI : 10.7776/ASK.2012.31.3.115
This paper investigates the effects of diffuser on the acoustical parameters in music hall with consideration of the result of scattering coefficient measurement. A scale model hall of 600 seats with orchestra shell was used for experiments. The materials of 1:50 scale model was chosen through absorption coefficient measurement based on ISO 354. The model was matched to the computer simulation model in terms of reverberation time. In order to evaluate the effect of diffuser location, the measurements were accomplished with and without diffusers according to 7 configurations by diffuser-installed region; sidewall, balcony front, ceiling and so on. The following acoustical parameters were extracted from each measurement case; Reverberation time (RT), Early decay time (EDT), Clarity (C80), Center time (Ts), Sound strength (G) and Temporal diffusion (TD) from the auto-correlation function (ACF) of impulse responses. As a result, the absorption power and diffusion power were increased with number of diffusers. Accordingly RT, EDT and G were decreased by diffuser and the redirection of reflections was occurred briskly. Averaged TD was 6.05 to 6.30 by measurement cases. RT was found to be the most related factor to diffusion power (R = 0.94). The correlation between TD and EDT was high (R = 0.73). In addition, the effects of diffuser-installed location were discussed in terms of acoustical parameter variation.
Comparison of the Korean and Chinese Speech Intelligibility with Increasing Sound Absorption in a Classroom
Ding, Wei ; Park, Chan-Jae ; Haan, Chan-Hoon ;
The Journal of the Acoustical Society of Korea, volume 31, issue 3, 2012, Pages 129~141
DOI : 10.7776/ASK.2012.31.3.129
The present study aims to investigates the effects of the physical sound clarity (D50, STI) on the subjective speech intelligibility of the both Korean and Chinese languages which can be caused by increase of the sound absorption in classroom. In order to this, sound measurements were undertaken at a classroom with and without absorption materials. Also, speech intelligibility tests were conducted by Korean and Chinese students using their native languages. As the results, it was found that both sound clarity and speech intelligibility were improved with increasing sound absorption. Also, it was revealed that Chinese speech intelligibility was more improved than Korean with same impose of sound absorption. It was considered by the difference of phonetic characteristics of two languages. Analysing correlation of physical sound clarity and subjective speech intelligibility, it was shown that D50 is highly correlated with Korean (0.696) and Chinese (0.707) respectively. Also, STI was highly correlated with Korean (0.651) and Chinese (0.665). Thus, it can be concluded that D50 and STI have significant correlations with the speech intelligibility.
Vibration of Pipes Coupled with Internal and External Fluids
Ryue, Jung-Soo ;
The Journal of the Acoustical Society of Korea, volume 31, issue 3, 2012, Pages 142~150
DOI : 10.7776/ASK.2012.31.3.142
The waveguide finite element (WFE) method is a useful numerical technique to investigate wave propagation along waveguide structures which have uniform cross-sections along the length direction ('x' direction). In the present paper, the vibration and radiated noise of the submerged pipe with fluid is investigated numerically by coupling waveguide finite elements and wavenumber boundary elements. The pipe and internal fluid are modelled with waveguide finite elements and the external fluid with wavenumber boundary elements which are fully coupled. In order to examine this model, the point mobility, dispersion curves and radiated power are calculated and compared for several different coupling conditions between the pipe and internal/external fluids.
Fast Acoustic Radiation Force Impulse Imaging Using Non-focused Transmission in Medical Ultrasound Imaging
Choi, Seung-Min ; Park, Jeong-Man ; Kwon, Sung-Jae ; Jeong, Mok-Kun ;
The Journal of the Acoustical Society of Korea, volume 31, issue 3, 2012, Pages 151~160
DOI : 10.7776/ASK.2012.31.3.151
In medical ultrasound imaging, elasticity imaging helps to diagnose tumors such as cancer. This paper is concerned with the application of acoustic radiation force to soft tissue of interest to implement elasticity imaging. In order to reduce the data acquisition time, instead of relying on transmit focusing, a plane wave of burst type is transmitted to apply the acoustic radiation force simultaneously to an entire imaging region to be observed. A homogeneous phantom experiment confirms that increasing the transmit excitation duration instead of employing transmit focusing generates a high enough acoustic radiation force to obtain elasticity images. It is found, however, that a different displacement versus time characteristic is observed unlike the case of using a conventional focused acoustic radiation force. Experimental results obtained through the use of an ultrasound phantom and a bovine liver show that lesions can be correctly differentiated.
Robust End Point Detection for Robot Speech Recognition Using Double Talk Detection
Moon, Sung-Kyu ; Park, Jin-Soo ; Ko, Han-Seok ;
The Journal of the Acoustical Society of Korea, volume 31, issue 3, 2012, Pages 161~169
DOI : 10.7776/ASK.2012.31.3.161
This paper presents a robust speech end-point detector using double talk detection in echoic conditioned speech recognition robot. The proposed method consists of combining conventional end-point detector result and double talk detector result. We have tested the proposed method in isolated word recognition system under echoic conditioned environment. As a result, the proposed algorithm shows superior performance of 30 % to the available techniques in the points of speech recognition rates.
The Automated Threshold Decision Algorithm for Node Split of Phonetic Decision Tree
Kim, Beom-Seung ; Kim, Soon-Hyob ;
The Journal of the Acoustical Society of Korea, volume 31, issue 3, 2012, Pages 170~178
DOI : 10.7776/ASK.2012.31.3.170
In the paper, phonetic decision tree of the triphone unit was built for the phoneme-based speech recognition of 640 stations which run by the Korail. The clustering rate was determined by Pearson and Regression analysis to decide threshold used in node splitting. Using the determined the clustering rate, thresholds are automatically decided by the threshold value according to the average clustering rate. In the recognition experiments for verifying the proposed method, the performance improved 1.4~2.3 % absolutely than that of the baseline system.
Noise Spectrum Estimation Using Line Spectral Frequencies for Robust Speech Recognition
Jang, Gil-Jin ; Park, Jeong-Sik ; Kim, Sang-Hun ;
The Journal of the Acoustical Society of Korea, volume 31, issue 3, 2012, Pages 179~187
DOI : 10.7776/ASK.2012.31.3.179
This paper presents a novel method for estimating reliable noise spectral magnitude for acoustic background noise suppression where only a single microphone recording is available. The proposed method finds noise estimates from spectral magnitudes measured at line spectral frequencies (LSFs), under the observation that adjacent LSFs are near the peak frequencies and isolated LSFs are close to the relatively flattened valleys of LPC spectra. The parameters used in the proposed method are LPC coefficients, their corresponding LSFs, and the gain of LPC residual signals, so it suits well to LPC-based speech coders.
Speaker Identification on Various Environments Using an Ensemble of Kernel Principal Component Analysis
Yang, Il-Ho ; Kim, Min-Seok ; So, Byung-Min ; Kim, Myung-Jae ; Yu, Ha-Jin ;
The Journal of the Acoustical Society of Korea, volume 31, issue 3, 2012, Pages 188~196
DOI : 10.7776/ASK.2012.31.3.188
In this paper, we propose a new approach to speaker identification technique which uses an ensemble of multiple classifiers (speaker identifiers). KPCA (kernel principal component analysis) enhances features for each classifier. To reduce the processing time and memory requirements, we select limited number of samples randomly which are used as estimation set for each KPCA basis. The experimental result shows that the proposed approach gives a higher identification accuracy than GKPCA (greedy kernel principal component analysis).
A Study on the Compensating System for the Acoustic Characteristics Caused by the Variation of Distance from Sound Source to Microphone
Jeoung, Byung-Chul ; Choe, Yoon-Sik ;
The Journal of the Acoustical Society of Korea, volume 31, issue 3, 2012, Pages 197~204
DOI : 10.7776/ASK.2012.31.3.197
In this thesis, studied the method to minimize the changes in frequency response and level due to the variation of the distance from the source to the microphone. selecting three microphones (omni directional, cardioid, super cardioid) which are being used generally, frequency responses were measured in accordance with the distance changes. Gotten the difference from the reference as the result of measurement, changed responses for each frequency range were compensated in comparison of the original human vocal source. In low frequency range, the low frequency boost caused by the proximity effect and decrease in accordance with the distance were compensated. The variation in mid-frequency range is comparatively small, however since the mid-range is the most important part of the human vocal signal, were compensated the mid-frequency range in comparison of the reference. The human vocal signal variation in high frequency range is extremely small and the high frequency is compensated close to the original source without difficulty. Understanding the microphone characteristics and compensations, this study showed that the response can be maintain among the change of the distance from the source to the microphone.