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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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The Journal of the Acoustical Society of Korea
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Journal DOI :
The Acoustical Society of Korea
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Volume & Issues
Volume 29, Issue 8 - Nov 2010
Volume 29, Issue 7 - Oct 2010
Volume 29, Issue 6 - Aug 2010
Volume 29, Issue 5 - Jul 2010
Volume 29, Issue 4 - May 2010
Volume 29, Issue 3 - Apr 2010
Volume 29, Issue 2 - Feb 2010
Volume 29, Issue 1 - Jan 2010
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Application of Ultrasonic Wave to the Squeezing Process From the Seeds
Kim, Jung-Soon ; Lee, Hui-Uk ; Kim, Moo-Joon ; Ha, Kang-Lyeol ;
The Journal of the Acoustical Society of Korea, volume 29, issue 2, 2010, Pages 91~96
To improve the limit of efficiency of squeezing oil in a conventional method, which seeds are compressed simply, the adoptability of the additional energy by the ultrasonic wave was investigated experimentally. As the results, using the ultrasonic vibration from the Langevin-type transducer, the efficiency was increased up to 25 %, whereas the conventional method has 15% efficiency. To investigate the additional pressure by the ultrasonic wave, the acoustic impedance of the sample and the vibration velocity of the transducer were measured. Although the amplitude of the ultrasonic is about 2.8 % of the compression pressure, the efficiency is increased a lot as mentioned above because the pressure is changed according to ultrasonic period.
Error in Variable FIR Typed System Identification Using Combining Total Least Mean Squares Estimation with Least Mean Squares Estimation
Lim, Jun-Seok ;
The Journal of the Acoustical Society of Korea, volume 29, issue 2, 2010, Pages 97~101
FIR type system identification with noisy input and output data can be solved by a total least squares (TLS) estimation. However, the performance of the TLS estimation is very sensitive to the ratio between the variances of the input and output noises. In this paper, we propose an iterative convex combination algorithm between TLS and least squares (LS). This combined algorithm shows robustness against the noise variance ratio. Consequently, the practical workability of the TLS method with noisy data has been significantly broadened.
Music Transcription Using Non-Negative Matrix Factorization
Park, Sang-Ha ; Lee, Seok-Jin ; Sung, Koeng-Mo ;
The Journal of the Acoustical Society of Korea, volume 29, issue 2, 2010, Pages 102~110
Music transcription is extracting pitch (the height of a musical note) and rhythm (the length of a musical note) information from audio file and making a music score. In this paper, we decomposed a waveform into frequency and rhythm components using Non-Negative Matrix Factorization (NMF) and Non-Negative Sparse coding (NNSC) which are often used for source separation and data clustering. And using the subharmonic summation method, fundamental frequency is calculated from the decomposed frequency components. Therefore, the accurate pitch of each score can be estimated. The proposed method successfully performed music transcription with its results superior to those of the conventional methods which used either NMF or NNSC.
Color Changes of Multi-Bubble Sonoluminescence Due to Metallic Ions in Water
Han, Moon-Su ; Lee, Jae-Wook ; Baek, Seung-Chan ; Baek, Jung-Hwan ; Kim, Young-H. ;
The Journal of the Acoustical Society of Korea, volume 29, issue 2, 2010, Pages 111~117
Sonoluminescence (SL) is the light emitting phenomenon accompanied with ultrasonic cavitation in liquid. It attracts many interests because physics behind it remains uncertain and few applications have appeared. It has been known that the color of SL changes in solutions which include metallic ions. In the present work, colors of SL in alkali metallic and alkaline earth metallic ions were considered. RGB component was used to analyze the color of SL. By using RGB component, it was found that color of SL in metallic solution can be resolved into color of SL in pure water and flame color of metal which is different from high intensity color of line spectrum of alkaline earth metal. From this result, influence of metallic ion on SL and the temperature on violent collapsing of cavitation bubble was discussed.
Optimum Design of Dynamic Vibration Absorber for Reducing Bending Vibrations of Two-Piece Vehicle Drive Line
Lee, Sang-Beom ; Yoo, Young-Sun ;
The Journal of the Acoustical Society of Korea, volume 29, issue 2, 2010, Pages 118~124
In this paper, design parameters of dynamic vibration absorber, which is used to reduce bending vibrations of a vehicle drive line, is optimized. For obtaining the correct dynamic response characteristics, a flexible-body drive line is made by applying the flexibility data extracted from vibration analysis of propeller shafts to the drive line dynamic model. Inner tube mass, rubber stiffness and rubber damping coefficient of the dynamic vibration absorber are taken as design parameters for optimization. To minimize the vertical acceleration of the drive line, a second-order regression equation of the objective function is generated by performing the central composite experimental design with 3 factors, 2 levels and 15 test runs. And the design parameters of the dynamic vibration absorber are determined by using optimization program. The vehicle model with optimized dynamic vibration absorber reduces the vertical acceleration peak of the drive line by 17.1 % in compared with the initial model.
Vocal Analysis of Talking Rooster
Kyon, Doo-Heon ; Bae, Myung-Jin ;
The Journal of the Acoustical Society of Korea, volume 29, issue 2, 2010, Pages 125~132
Since the ancient times, animals that can imitate the voices of human beings have been considered extremely special. There are very few such animals, and the parrot is an example of them. For a long time, there had been no reported case of a rooster being able to mimic the voice of a human being, but talking roosters were recently found in Korea and the Kyrgyz Republic, generating much talk. In this study, the vocal characteristics of such roosters were examined, and their pronunciation-related statistics and actual sound sources were analyzed. The analysis results showed that even though the roostets cannot converse with people, they can imitate the human voice, uttering the words "An-dwae," and "A-ni-ya" in Korean, which mean "No" in English, when someone tries to catch their wings. A similar situation 'occurred in the Kyrgyzstan. The results of the listening survey on these sounds made by the roosters showed that most people recognized the words uttered by the roosters and that nobody thought that the words sounded like "cock-a-doodle-doo." It can be said that such roosters can make the sounds of the human voice because of their innate vocal organ and characteristics, which are significantly different from those of the general roosters. Their vocal organ and characteristics cause the sounds that they make to change in their vocal cords due to their high tension when humans try to catch them.
New Temporal Features for Cardiac Disorder Classification by Heart Sound
Kwak, Chul ; Kwon, Oh-Wook ;
The Journal of the Acoustical Society of Korea, volume 29, issue 2, 2010, Pages 133~140
We improve the performance of cardiac disorder classification by adding new temporal features extracted from continuous heart sound signals. We add three kinds of novel temporal features to a conventional feature based on mel-frequency cepstral coefficients (MFCC): Heart sound envelope, murmur probabilities, and murmur amplitude variation. In cardiac disorder classification and detection experiments, we evaluate the contribution of the proposed features to classification accuracy and select proper temporal features using the sequential feature selection method. The selected features are shown to improve classification accuracy significantly and consistently for neural network-based pattern classifiers such as multi-layer perceptron (MLP), support vector machine (SVM), and extreme learning machine (ELM).
Single-Channel Speech Separation Using Phase Model-Based Soft Mask
Lee, Yun-Kyung ; Kwon, Oh-Wook ;
The Journal of the Acoustical Society of Korea, volume 29, issue 2, 2010, Pages 141~147
In this paper, we propose a new speech separation algorithm to extract and enhance the target speech signals from mixed speech signals by utilizing both magnitude and phase information. Since the previous statistical modeling algorithms assume that the log power spectrum values of the mixed speech signals are independent in the temporal and frequency domain, discontinuities occur in the resultant separated speech signals. To reduce the discontinuities, we apply a smoothing filter in the time-frequency domain. To further improve speech separation performance, we propose a statistical model based on both magnitude and phase information of speech signals. Experimental results show that the proposed algorithm improve signal-to-interference ratio (SIR) by 1.5 dB compared with the previous magnitude-only algorithms.
IMBE Model Based SNR Estimation of Continuous Speech Signals
Park, Hyung-Woo ; Bae, Myung-Jin ;
The Journal of the Acoustical Society of Korea, volume 29, issue 2, 2010, Pages 148~153
In speech signal processing, speech signal corrupted by noise should be enhanced to improve quality. Usually noise estimation methods need flexibility for variable environment. Noise profile is renewed on silence region to avoid effects of speech properties. So we have to preprocess finding voice region before noise estimation. However, if received signal does not have silence region, we cannot apply that method. In this paper, we proposed SNR estimation method for continuous speech signal. A Speech signal consists of Voice and Unvoiced Band in The MBE excitation model. And the energy of speech signal is mostly distributed on voiced region, so we can estimate SNR by the ratio of voiced region energy to unvoiced. We use the IMBE vocoder for the Voice or Unvoice band of segmented speech signal. Continuously we calculate the segmented SNR using that information and the energy of each band. And we estimate the SNR of continuous speech signal.