• The Journal of Korean Academy of Prosthodontics
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• v.27 no.1
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• pp.83-102
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• 1989

This study was done to analyze the sound distortion, before and after insertion of the palatal palates. For this study, 4 healthy subjects (3 males and 1 female, each 24-year-old), who were born in Seoul were recruited from K university, and 3 type palatal plates were fabricated, each palatal thickness being 1.0mm, 2.5mm, dentoalveolar portion 2.5mm and elsewhere 1.0mm, named B,C,D-type repectively, and informants's sounds of /사(sa), 서(se), 소(so), 수(su), 스($s\.{+}$), 시(si)/ were recorded, without plate, and with palatal plates of different types, in succession. A series of analysis were adminstered through a 16 Bit IBM PC/AT using linear combination methods. These experiments were analyzed by the Cepstrum (Weighted and Euclidian), Log Area Ratio, Linear prediction correlation methods The findings led to the following conclusions : 1. It was confirmed that the same consonant, /ㅅ(s)/, variously distorted by the following vowel. 2. By and large, 시($s\.{+}$) was the most distorted in all conditions, and (sa), 소(so) were the least distorted in each condition. 3. There were no persistant correlation of the palatal plate types, and sound distortions of each informant were diverse with no regularities. 4. There were persistent correaltion to the Cepstrum (Weighted, Euclidian), Log Area Ratio. However, Linear prediction correlation has a different alteration pattern.

• Journal of Korea Multimedia Society
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• v.6 no.2
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• pp.216-223
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• 2003

In this paper, we present SCCRS(Speech and Character Combined Recognition System) for speaker /writer independent. on-line multimodal interfaces. In general, it has been known that the CHMM(Continuous Hidden Markov Mode] ) is very useful method for speech recognition and on-line character recognition, respectively. In the proposed method, the same CHMM is applied to both speech and character recognition, so as to construct a combined system. For such a purpose, 115 CHMM having 3 states and 9 transitions are constructed using MLE(Maximum Likelihood Estimation) algorithm. Different features are extracted for speech and character recognition: MFCC(Mel Frequency Cepstrum Coefficient) Is used for speech in the preprocessing, while position parameter is utilized for cursive character At recognition step, the proposed SCCRS employs OPDP (One Pass Dynamic Programming), so as to be a practical combined recognition system. Experimental results show that the recognition rates for voice phoneme, voice word, cursive character grapheme, and cursive character word are 51.65%, 88.6%, 85.3%, and 85.6%, respectively, when not using any language models. It demonstrates the efficiency of the proposed system.

• The Journal of the Acoustical Society of Korea
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• v.29 no.1
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• pp.69-75
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• 2010

In this paper, the pitch is detected after the elimination of formant ingredients by flattening the spectrum in frequency domain. In order to remove impact of formant and transition frequency in the signal spectrum, formant envelop is made by linear interpolation with any points each sub-band and the spectrum of speech signal is compensated by the reverse of the envelop interpolated linearly after we divide frequency band into several segment based on LSP and detect the points. The experimental result showed the proposed method appeared an outstanding performance in compared with LPC, Cepstrum, Lifter methods. The method reduced the gross error rate 1.30% than the LPC method which appeared a good performance except the proposed method. Also, the proposed method showed low error rate in noise environment.

• Journal of the korean Society of Automotive Engineers
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• v.8 no.3
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• pp.1-8
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• 1986

자동차 동력전달계통의 중요부분을 이루고 있는 치차장치는 고장의 영향도가 대단히 높은 장치일 뿐만 아니라 점검과 열화, 손상검지가 곤란한 장치이다. 지금까지, 치차진단기술의 연구는, 구미 에서는 성행하고 있음에도 불구하고, 국내에서는 그다지 되고있지 않다. 이와 같은 상황을 근거로 하여, 본 연구실에서는 치차진단기술의 연구개발에 착수하여, 그 첫 번째 단계로서, 현상의 기술 및 연구내용을 조사하였다. 그들중에서 중요하다고 생각되는 것을 여기에 소개한다. 치차장치의 내부에 이상이 생기면, 진동과 이음이 생기기도 하고 속도변동 등을 일으킨다. 또, 윤활유 중의 금속분이 증가하거나, 온도가 상승하기도 한다. 이와같은 이상의 정보를 포함하는 것을 징후 parameter라고 말한다. 이들 몇 개인가의 parameter중, 치차결함의 검출은, 진동과 음이 가장 좋은 parameter라고 생각되고 있다. 따라서 진단기술의 연구는, 거의 대개가 치차로부터 나오는 진동과 음의 발생기구와 신호처리에 관한 것이다. 전자로는 (1) 치차의 마모모델과 발생진동수 (2) 각종 결함고 발생진동수 후자로는 (3) 시간평균화처리 (4) Cepstrum (5) fluctuation 분석 등이 있다.

• Phonetics and Speech Sciences
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• v.4 no.3
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• pp.119-125
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• 2012

This paper describes a new algorithm for encoding spectral shape and envelope in the generic mode of G.718 super-wide band (SWB). In the G.718 SWB coder, generic mode coding and sinusoidal enhancement are used for the quantization of modified discrete cosine transform (MDCT)-based parameters in the high frequency band. In the generic mode, the high frequency band is divided into sub-bands and for every sub-band the most similar match with the selected similarity criteria is searched from the coded and envelope normalized wideband content. In order to improve the quantization scheme in high frequency region of speech/audio signals, the modified generic mode by the improvement of the generic mode in G.718 SWB is proposed. In the proposed generic mode, perceptual vector quantization of spectral envelopes and the resolution increase for spectral copy are used. The performance of the proposed algorithm is evaluated in terms of objective quality. Experimental results show that the proposed algorithm increases the quality of sounds significantly.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1413-1415
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• 2004

This paper proposes a SVM(Support Vector Machine) training algorithm to control a service robot with voice command. The service robot with a stereo vision system and dual manipulators of four degrees of freedom implements a User-Dependent Voice Control System. The training of SVM algorithm that is one of the statistical learning theories leads to a QP(quadratic programming) problem. In this paper, we present an efficient SVM speech recognition scheme especially based on less learning data comparing with conventional approaches. SVM discriminator decides rejection or acceptance of user's extracted voice features by the MFCC(Mel Frequency Cepstrum Coefficient). Among several SVM kernels, the exponential RBF function gives the best classification and the accurate user recognition. The numerical simulation and the experiment verified the usefulness of the proposed algorithm.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.33B no.11
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• pp.97-105
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• 1996

This paper is a study on the implementation of speech recognition mobile robot to which the interactive speech recognition techniques is applied. The speech command uttered the sentential connected word and is asserted through the wireless mic system. This speech signal transferred LPC-cepstrum and shorttime energy which are computed from the received signal on the DSP board to notebook PC. In notebook PC, DP matching technique is used for recognizer and the recognition results are transferred to the motor control unit which output pulse signals corresponding to the recognized command and drive the stepping motor. Grammar network applied to reduce the recognition speed of the recogniger, so that real time recognition is realized. The misrecognized command is revised by interface revision through the conversation with mobile robot. Therefore, user can move the mobile robot to the direction which user wants.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.89-92
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• 1999

인식기 훈련과정에서 발생하지 않았던 잡음이 인식과정에서 신호를 손상할 경우 인식률의 저하가 발생한다. 본 논문에서는 음성의 질을 떨어뜨리는 이러한 잡음을 Wavelet Packets을 이용하여 전처리함으로서 인식률을 향상시키는 방법을 제안한다. 인식기로는 Hidden Markov Model을 사용하였고, 시스템에 사용된 특징 파라미터로는 15차 Cepstrum을 사용하였다. 11 kHz로 샘플링된 숫자음에 Additive White Gaussian Noise를 첨가한 손상된 음성신호를 인식실험에 사용하였다. 화자독립으로 진행된 실험에서 잡음에 의해 손상된 SNR 20dB의 음성신호에 대하여 Wavelet Packets로 잡음을 제거한 후 복원된 음성신호 의 인식률은 약 $10\%$ 향상됨을 확인하였다.

• Proceedings of the Acoustical Society of Korea Conference
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• autumn
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• pp.269-272
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• 1999

물체내부의 단층구조를 나타내는 B-모드 영상은, 물체의 내부 경계로부터의 반사신호를 직접 비디오 신호로 변환하여 그 진폭에 비례하는 휘도 또는 색상으로 나타내고 있다. 그러한 시간영역 파형에 의한 처리에 있어서는 각 신호가 시간적으로 근접해 있을 경우 영상화가 곤란하다. 본 연구에서는 B-모드 영상에 있어서 거리분해능을 향상시키기 위한 방법으로 캡스트럼법을 이용하는 것을 제안하고, 그 방법에 의해 음속이 알려진 얇은 물체의 두께를 보다 정확하게 측정, 표시함으로써 B-모드 영상화에 있어서의 분해능 향상 가능성을 보였다.

• The Journal of the Acoustical Society of Korea
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• v.23 no.4E
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• pp.134-139
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• 2004

It is generally known that accurate segmentation is very necessary for both an individual word and continuous utterances in speech recognition. It is also commonly known that techniques are now being developed to classify the voiced and the unvoiced, also classifying the plosives and the fricatives. The method for accurate recognition of the phonemes isn't yet scientifically established. Therefore, in this study we analyze the Korean language, using the classification of 'Hunminjeongeum' and contemporary phonetics, with the frequency band, Mel band and Mel Cepstrum, we extract notable features of the phonemes from Korean speech and segment speech by the unit of the phonemes to normalize them. Finally, through the analysis and verification, we intend to set up Phonemic Segmentation System that will make us able to adapt it to both an individual word and continuous utterances.