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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 10, Issue 6 - Dec 1991
Volume 10, Issue 5 - Oct 1991
Volume 10, Issue 4 - Aug 1991
Volume 10, Issue 3 - Jun 1991
Volume 10, Issue 2 - Apr 1991
Volume 10, Issue 1 - Feb 1991
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A Study on the Method of Assessing Spatial Speech Transmission Quality as an Indicator of Room Acoustics -Concentrated on the Articulation Test under Variable Ambient Noise-
Han, Myung-Ho ; Lee, Tae-Gang ; Oh, Yang-Ki ; Kim, Sun-Woo ;
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 5~11
Articulation test is a good predictor of spatial speech transmission quality. Like many other languages, articulation testing method using Korean language was proposed in 1989, and which was proved as a valid indicator in rooms with static background noise. In this paper, the testing method is examined in variable noise conditions. According to the experiment performed in 26 classrooms with variable background noise, the proposed articulation testing method using Korean Language is still in variable conditions.
Nonlinear Aspects of the Frequency Response of a Gas-filled Bubble Oscillator
Kim, Dong-Hyuk ; Kim, Jeung-Tae ; Lee, Yong-Bong ;
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 12~19
A numerical analysis is carried out for the nonlinear phenomena of the bubble oscillator. The model is based on the Keller's formulation for the bubble dynamics. Interpretation of the bubble interior is based on the formulation by Prosperetti. His formulation adopts the energy equation for the analysis of the bubble interior. The numerical simulation Shows typical nonlinear phenomena in its frequency response. Among such nonlinear aspects are the jump phenomenon, the shift of natural frequency of the system, and the appearance of superharmonic resonances. It is deduced that the nonlinear frequency response is dependent upon the initial condition of the bubble oscillator and some multi-valued frequency region can appear in the response curve. Nonlinear phenomena appeared in the bubble oscillator is compared with those of the Duffing equation and it may be said that the bubble dynamic equation has similar nonlinear aspects to the Duffing equation.
A Study on A Multi-Pulse Linear Predictive Filtering And Likelihood Ratio Test with Adaptive Threshold
Lee, Ki-Yong ; Lee, Joo-Hun ; Song, Iick-Ho ; Ann, Sou-Guil ;
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 20~29
A fundamental assumption in conventional linear predictive coding (LPC) analysis procedure is that the input to an all-pole vocal tract filter is white process. In the case of periodic inputs, however, a pitch bias error is introduced into the conventional LP coefficient. Multi-pulse (MP) LP analysis can reduce this bias, provided that an estimate of the excitation is available. Since the prediction error of conventional LP analysis can be modeled as the sum of an MP excitation sequence and a random noise sequence, we can view extracting MP sequences from the prediction error as a classical detection and estimation problem. In this paper, we propose an algorithm in which the locations and amplitudes of the MP sequences are first obtained by applying a likelihood ratio test (LRT) to the prediction error, and LP coefficients free of pitch bias are then obtained from the MP sequences. To verify the performance enhancement, we iterate the above procedure with adaptive threshold at each step.
A Study on Determining Complex Young's Modulus of Acoustic Materials
Kim, In-Su ; Lee, Hyo-Keun ; Kim, Sung-Hee ;
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 30~36
Since the Complex Young's Modulus of acoustic materials is a function of frequency under a static load, a cylindrical specimen modelled by rod-like one with losses is used to determine the dynamic characteristics of materials. The specimen is excited into longitudinal vibration at its one end by shaker and at the other end, loaded by a mass corresponding to the desired static load and thus the transfer function of specimen is measured. This transfer function method is analyzed theoretically and experimentally over a frequency range of 50 Hz to 20 KHz. The analysis includes the measurability of the transfer function, the frequency range of the method and lateral motion effect.
On the Center Pitch Estimation by using the Spectrum Leakage Phenomenon for the Noise Corrupted Speech Signals
Kang, Dong-Kyu ; Bae, Myung-Jin ; Ann, Sou-Guil ;
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 37~46
The pitch estimation algorithms witch have proposed until now are difficult to detect wide range pitches regardless of age or sex. A little deviation are observed with reference to the center pitch in the distribution diagram of pitches, since pitches are characterized by a physical limitation of the coarticulation mechanism. If the center pitches are refered to the accurate pitch extraction procedure, the algorithms will be not only simplified in procedure but also improved in accuracy. In this paper, we proposed an algorithm that the center pitches are accurately detected by using the spectrum leakage phenomenon for the noise speech signals.
Collective Oscillations of a Bubble Cloud as a Source of Underwater Ambient Noise in the Ocean
Yoon, S.W. ; Park, K.J. ; Crum, L.A. ;
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 47~51
it is well observed in the ocean that the surface disturbances due to rain, wind and breaking waves generate bubble clouds several meters deep from the water surfaces. Thses kinds of bubble clouds can work as a physical mechanism to produce underwater ambient noise. In the laboratory experiment observing the noise generated from a bubble cloud we showed a role of individual bubbles in collective oscillations of a bubble cloud. The experimental data agree very well with the theoretical predictions. These results confirm that the collective oscillations of a bubble cloud is one of the more likely mechanisms for an ocean ambient noise source around several hundred hertz.
Korean Speech Recognition using DHMM
Ann, T.O. ; Lee, K.S. ; Yoo, H.K. ; Lee, H.J. ; Cho, H.J. ; Byun, Y.G. ; Kim, S.H. ;
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 52~60
This paper describes the study on isolated word recognition by using DHMM(Dynamic Hidden Markov Model) which has dynamic feature of spectrum as a parameter. This paper discusses speech recognition experiment basedon HMM which can evaluate not only instantaneous spectral features but also dynamic spectral features. LPC cepstrum parameters is used as a static feature and LPC cepstrum's regression coefficient is used as a dynamic feature. These two features are quantized by each VQ codebook. DHMM is modeled by receiving static vector and dynamic vector by input. In the whole experiment, as recognition experiment using DHMM shows 92.7% of recognition rate while the experiment using conventional HMM shows 88.8% of recognition rate, DHMM proved to be a useful model.
The Noise of Highway and Counterplan for Reduction of it
Chung, Il-Rock ; Kang, Dae-Joon ; Lee, Woo-Suck ; Seok, Kwang-Sul ; Kim, Yang-Kun ;
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 61~70
We investigate the equivalent noise level at 30 sites where the noise barrier has been built in highways, and develop the new prediction model of it in order to provide the reasonable guideline of construction of the noise barrier. We find the several interesting facts of many sided measurement and analysis.
Surface Acoustic Wave Signal Processing Devices
Whang, Keum-Chan ; Lee, Dong-Wook ;
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 71~82
Automatic Speech Recognition Research at Fujitsu
Nara, Yasuhiro ; Kimura, Shinta ; Loken-Kim, K.H. ;
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 82~91
The history of automatic speech recognition research, and current and future speech products at Fujitsu are introduced here. The speech recognition research at Fujitsu started in 1970. Our research efforts have results in the production of a speaker dependent 12,000 word discrete / connected word recognizer(F2360), and a speaker independent 17 word discrete word recognizer(F2355L/S). Currently, we are working on a larger vocabulary speech recognizer, in which an input utterance will be matched with networks representing possible phonemic variations. Its application to text input is also discussed.
제2차 NATO Natural Physical Sources of Underwater Sound 학술회의 참석기
The Journal of the Acoustical Society of Korea, volume 10, issue 1, 1991, Pages 92~96