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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
Editor in Chief :
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 Recognition of Korean Connected-Digits Using group-labelling by VQ and One-stage DP
Kim, Ja-Ryong ; Choi, Kap-Seok ;
The Journal of the Acoustical Society of Korea, volume 10, issue 2, 1991, Pages 5~12
In this paper, we have recognized Korean connected-digits. To reduce the processing time the method of combining VQ one-stage DP is introduced and to reduce the number of reference pattern a new group labelling technique is proposed. Group-labelling is a method to segment and label connected-digit into groups by VQ. As experimental results with 3 connected-digits, the number of reference patterns are reduced in proportion to the number of groups which are labelled.
Experimental Study on the Static Balancing Method of an Unbalanced Rigid Rotor
Chang, Ho-Gyeong ; Kim, Sung-Kyu ; Kim, Ye-Hyun ;
The Journal of the Acoustical Society of Korea, volume 10, issue 2, 1991, Pages 13~22
The presence of an unbalanced mass is originated the common source of vibration in machines with rotating rotor. In this study, the unbalanced rigid rotor mounted on an overhang shaft is balanced using the static balancing procedure, and the compensation mass is estimated by the phase angle method and four run method. Also, the reduction of vibration level before and after balancing is examined. In the experimental results, it is shown that the vibration due to the unbalanced mass is decreased by eliminating the effect of the unbalance. Above all, the four run method is proved more effective on the ability of vibration reduction, in small unbalanced mass, the phase angle method.
Isolated Word Recognition using Modified Dynamic Averaging Method
Jeoung, Eui-Bung ; Ko, Young-Hyuk ; Lee, Jong-Arc ;
The Journal of the Acoustical Society of Korea, volume 10, issue 2, 1991, Pages 23~28
This paper is a study on isolated word recognition by independent speaker, we propose DTW speech recognition system by modified dynamic averaging method as reference pattern. 57 city names are selected as recognition vocabulary and 2th LPC cepstrum coefficients are used as the feature parameter. In this paper, besides recognition experiment using modified dynamic averaging method as reference pattern, we perform recognition experiments using causal method, dynamic averaging method, linear averaging method and clustering method with the same data in the same conditions for comparison with it. Through the experiment result, it is proved that recogntion rate by DTW using modified dynamic averaging method is the best as 97.6 percent.
Isolated Word Recognition Using Allophone Unit Hidden Markov Model
Lee, Gang-Sung ; Kim, Soon-Hyob ;
The Journal of the Acoustical Society of Korea, volume 10, issue 2, 1991, Pages 29~35
In this paper, we discuss the method of recognizing allophone unit isolated words using hidden Markov model(HMM). Frist we constructed allophone lexicon by extracting allophones from training data and by training allophone HMMs. And then to recognize isolated words using allophone HMMs, it is necessary to construct word dictionary which contains information of allophone sequence and inter-allophone transition probability. Allophone sequences are represented by allophone HMMs. To see the effects of inter-allophone transition probability and to determine optimal probabilities, we performend some experiments. And we showed that small number of traing data and simple train procedure is needed to train word HMMs of allophone sequences and that not less performance than word unit HMM is obtained.
Analysis of Acoustic Back Scattering from Bubble Columns in Water
Park, K.-J. ; Yoon, S.-W. ; Roy, R.A. ;
The Journal of the Acoustical Society of Korea, volume 10, issue 2, 1991, Pages 36~43
Acoustic backscattering from a buble column in water was studied theoretically and experimentally. For theoretical analysis a general scattering theory was used by assuming the bubble column to be lumped element scatterer which can be characterized by its shape, void fraction and dimensions. When the void fraction is less than 1% and the incident frequency is higher than individual bubble resonance frequencies, the experimental results show that the acoustic backscattering from a bubble column depends mainly on the void fraction rather than the individual bubble sizes. It was also theoretically and experimentally observed that the acoustic backscattering levels were increased and their peaks moved to the lower frequency regin by raising the void fraction of bubble column.
An Implementation of FM-extended Stereo System via Application of Quadrature Modulation and Companding Method
Heo, Dong-Kyu ; Kim, Kee-Keun ; Kim, Ju-Koang ; Ryu, Heung-Gyoon ;
The Journal of the Acoustical Society of Korea, volume 10, issue 2, 1991, Pages 44~51
In this paper, we have studied the FM-extended broadcasting which makes the enhancement of stereo signal-to-noise ration by utilizing the compression technique and quadrature moduation method of standard subcarrier signal in transmitter station, and corresponding demodulation method and expansion technique in receiver system. The proposed system is completely compatible with the conventional FM stereo system. We have confirmed the validity of the proposed method by implementation of transmitter/receiver system including quadrature modulation/demodulation and companding system.
Model Experiments for Acoustic Propagation Characteristics in the Across Slope Direction of the Sloping Sea Bed
Yoon, Jong-Rak ;
The Journal of the Acoustical Society of Korea, volume 10, issue 2, 1991, Pages 52~60
Sound propagation in a sloping sea bed ocean environment demonstrates ray curvature in a direction parallel to the shoreline. The theoretical analysis of this shows that an ensonified region and a shadow region are formed, and their spatial extents depend on the spatial coordinates of source and receiver, a sloping angle and sourece frequency. The purpose of this experimental study using a sloping sea bed model is to check the theoretical prediction as a part of an ongoing investigation in the ocean environment. The sloping sea bed model used in this experiment had an ideal pressure-release boundaries and a sloping angle of
A single frequency signal and an impulsive signal were used as omnidirectional point sources. The spatial acoustic field characteristics in the across slope direction were measured using the former and the frequency dependent field characteristics in a specific point were obtained using the latter. It has been found that the analysis for the spatial extent of shadow zone and the frequency dependent field characteristics in the across slope direction, has a good agreement with the theoretical solution.
Noise and Residential Environments
Lee, Gwang-Tae ;
The Journal of the Acoustical Society of Korea, volume 10, issue 2, 1991, Pages 61~67
A Survey of Air-Borne Sound and Sound Insulation in Structure
Lee, Sang-Woo ;
The Journal of the Acoustical Society of Korea, volume 10, issue 2, 1991, Pages 68~77
Noise Reduction of Air-borne Sound
Shin, Young-Moo ;
The Journal of the Acoustical Society of Korea, volume 10, issue 2, 1991, Pages 78~84