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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 13, Issue 6 - Dec 1994
Volume 13, Issue 5 - Oct 1994
Volume 13, Issue 4 - Aug 1994
Volume 13, Issue 3 - Jun 1994
Volume 13, Issue 2 - Apr 1994
Volume 13, Issue 1 - Feb 1994
Volume 13, Issue 2E - 00 1994
Volume 13, Issue 1E - 00 1994
Selecting the target year
Classification of Korean Character Type using Multi Neural Network and Fuzzy Inference based on Block Partition for Each Type
Pyeon, Seok-Beom ; Park, Jong-An ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 5~11
In this paper, the ciassification of Korean character type using multi neural network and fuzzy inference based on block partition is studied. For the effective classification of a consonant and a vowel, block partition method which devide the region of a consonant and a vowel for each type in the character is proposed. And the partitioned block can be changed according to the each type adaptively. For the improvement of classification rate, the multi neural network with a whole and a part neural network is consisted, and the character type by using fuzzy inference is decided. To verify the validity of the proposed method, computer simulation is accomplished, and from the classification rate
, the effectivity of the method is confirmed.
Phoneme Recognition Using Frequency State Neural Network
Lee, Jun-Mo ; Hwang, Yeong-Soo ; Kim, Seong-Jong ; Shin, In-Chul ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 12~19
This paper reports a new structure for phoneme recognition neural network. The proposed neural network is able to deal with the structure of the frequency bands as well as the temporal structure of phonemic features which used in the conventional TSNN. We trained this neural network using the phonetics (아, 이, 오, ㅅ, ㅊ, ㅍ, ㄱ, ㅇ, ㄹ, ㅁ) and the phoneme recognition of this neural network was a little better than those of conventional TDNN and TSNN using only temporal structure of phonemic features.
Simplified Maximum Likelihood Estimation of the Frequencies of Multiple Sinusoids
Ahn, Tae-Chon ; Oh, Sung-Kwun ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 20~31
The maximum likelihood(ML) estimation has excellent accuracy for frequency estimation of multiple sinusoids, but the maximum likelihood function requires much loss owing to the high nonlinearity. This paper presents a simplified maximum likelihood estimation, in order to improve the nonlinearity of the maximum likelihood estimation for frequencies of sinusoids in signals. This method is applied to the frequency estimation of sinusoidal signals corrupted by white or colored measurement noise. Monte-carlo simulations are conducted for the comparison of ML method with the best MFBLP method, in terms of sampled mean, root mean square and relative bias. The power spectral density and the position of frequency in unit circle are appeared in figures.
A Study on Duration Length and Place of Feature Extraction for Phoneme Recognition
Kim, Bum-Koog ; Chung, Hyun-Yeol ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 32~39
As a basic research to realize Korean speech recognition system, phoneme recognition was carried out to find out ; 1) the best place which represents each phoneme's characteristics, and 2) the reasonable length of duration for obtaining the best recognition rates. For the recognition experiments, multi-speaker dependent recognition with Bayesian decision rule using 21 order of cepstral coefficient as a feature parameter was adopted. It turned out that the best place of feature extraction for the highest recognition rates were 10~50ms in vowels, 40~100ms in fricatives and affricates, 10~50ms in nasals and liquids, and 10~50ms in plosives. And about 70ms of duration was good enough for the recognition of all 35 phonemes.
Korean Word Recognition using the Transition Matrix of VQ-Code and DHMM
Chung, Kwang-Woo ; Hong, Kwang-Seok ; Park, Byung-Chul ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 40~49
In this paper, we propose methods for improving the performance of word recognition system. The ray stratey of the first method is to apply the inertia to the feature vector sequences of speech signal to stabilize the transitions between VQ cdoes. The second method is generating the new observation probabilities using the transition matrix of VQ codes as weights at the observation probability of the output symbol, so as to take into account the time relation between neighboring frames in DHMM. By applying the inertia to the feature vector sequences, we can reduce the overlapping of probability distribution of the response paths for each word and stabilize state transitions in the HMM. By using the transition matrix of VQ codes as weights in conventional DHMM. we can divide the probability distribution of feature vectors more and more, and restrict the feature distribution to a suitable region so that the performance of recognition system can improve. To evaluate the performance of the proposed methods, we carried out experiments for 50 DDD area names. As a result, the proposed methods improved the recognition rate by
in the speaker-dependent test and
in the speaker-independent test, respectively, compared with the conventional DHMM.
Reseiver processing circuit design and its performance evaluation of the ERMES system
Jeoung, Eun-Taek ; Lee, Sang-Gon ; Yoon, Ki-Hoo ; Ryu, Heung-Gyoon ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 50~59
The pan-european paging system European Radio MEssage System (ERMES), a new system of digital information communication, has 16 channels with 25KHz channel spacing. The ERMES modulation format is 4-PAM/FM. The ERMES operates in the frequency range 169.4125MHz
169.8125MHz. In this paper, an ERMES receiving system according to the European Telecommunication Standard Institute(ETSI) specfication with a double error correction capability is designed. The ERMES receiver system is designed with the conventional circuit and its error performance for muitiple signal modulated by the 4-PAM/FM method are analyzed. Since amplitude imbalance among the signal components can impair the system performance when several receivers are operated on the same RF channel simultaneously, the optimal parameters are obtained in designing the radio system. Performance of the proposed receiver system is verified via computer simulation for processing procedure.
A Study on the Implementation of Hybrid Learning Rule for Neural Network
Song, Do-Sun ; Kim, Suk-Dong ; Lee, Haing-Sei ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 60~68
In this paper we propose a new Hybrid learning rule applied to multilayer feedforward neural networks, which is constructed by combining Hebbian learning rule that is a good feature extractor and Back-Propagation(BP) learning rule that is an excellent classifier. Unlike the BP rule used in multi-layer perceptron(MLP), the proposed Hybrid learning rule is used for uptate of all connection weights except for output connection weigths becase the Hebbian learning in output layer does not guarantee learning convergence. To evaluate the performance, the proposed hybrid rule is applied to classifier problems in two dimensional space and shows better performance than the one applied only by the BP rule. In terms of learning speed the proposed rule converges faster than the conventional BP. For example, the learning of the proposed Hybrid can be done in 2/10 of the iterations that are required for BP, while the recognition rate of the proposed Hybrid is improved by about
at the peak.
On the Development of Monosyllable Lists for Articulation Tests
Kim, Jeong-Hwan ; Kang, Seong-Hoon ; Jang, Dae-Young ; Kim, Cheon-Duck ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 69~76
In this study we developed monosyllable lists for articulation test for Korean. We sampled 103, 581 colloquial monosyllables, applied them to five selection rules that based on Korean linguistic characterisitcs, and finally constructed five different lists with fifity monosyllables. The validity test using the monaural impairment factors such as S/N ratio and cut-off frequency showed that articulation scores were changed systematically according to the level of impairment factors. In addition, we investigated the effect of azimuth of a single competing sound source upon articulation scores. The syllables were always reproduced by the loudspeaker in front of the subject, while Hoth noise( -5dB/oct) were reproduced by the loudspeaker with varying azimuth around subject. The result indicated that the articulation depended on the azimuth of competing sound sources and no significant differences among lists were found in all experimental conditions.
Variable Length Optimum Convergence Factor Algorithm for Adaptive Filters
Boo, In-Hyoung ; Kang, Chul-Ho ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 77~85
In this study an adaptive algorithm with optimum convergence factor for steepest descent method is proposed, which controls automatically the filter order to take the appropriate level. So far, fixed order filters have been used when adaptive filter is employed according to the priori knowledge or experience in various adaptive signal processing applications. But, it is so difficult to know the filter order needed in real implementations that high order filters have to be performed. As a result, redundant calculations are increased in the case of high order filters. The proposed variable length optimum convergence factor (VLOCF) algorithm takes the appropriated filter order within the given one so that the redundant calculation is decreased to get the enhancement of convergence speed and smaller convergence error during the steady state. The proposed algorithm is evaluated to prove the validity by computer simulation for system Identification.
Oceanic Acoustic Tomography and Inverse Problem
Lee, Jae-Hak ; Kim, Jae-Su ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 86~93
Underwater Acoustic Telemetry
Song, Hui-Cheon ;
The Journal of the Acoustical Society of Korea, volume 13, issue 4, 1994, Pages 94~101