• Proceedings of the KSPS conference
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• 2005.11a
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• pp.193-198
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• 2005

The aim of this paper is to exam why the nouns that used /kh, ph, ts, th/, as the final phoneme changed. Assuming that these change related to the aspects of the word usage, we collected the word frequency and the phonetic form of words. The results are as follows : ① The realization of standard phonetic form is related to the frequency of case marker that could not be omitted, combined with the word. ② The changing into /s/ in a coronal consonant is related to the case marker [i].

• Speech Sciences
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• v.12 no.3
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• pp.59-77
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• 2005

The aim of the present study is to investigate how the phonemic characteristics influence on the disfluencies of children and adults who stutter. The participants were 10 children(9 boys and 1 girl) and 10 male adults. After having the participants to read out the Paradise-Fluency Assessment(Sim, Shin & Lee, 2004) passages, each of the productions were divided into syllables and words, and then the frequencies and the ratios of their disfluenceis were analyzed according to the specified phonemic features. In terms of the frequency of the disfluency, the participants stuttered more in the words which start with consonant than vowel. But they showed more disfluencies in the words initiated with vowel than consonant when the ratio of each phoneme's presences were considered. There found different tendencies among the phonemic features related with their disfluencies occuring with ralatively high frequency or ratio. It was difficult to find out the exact relationships among the order of the sound acquisition, phonemic complexity, and the disfluencies. To study the exact influence of the phonemic features upon the disfluencies, it comes important to consider the frequency of the stuttering itself together with the ratio of the disfluencies in which the opportunity of the specific sound's presence was considered. To compare the results of the different studies which has similar purposes, it seems important to consider the tasks and the methodologies in depth.

• The Journal of the Acoustical Society of Korea
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• v.21 no.3
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• pp.310-314
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• 2002

The exact pitch (fundamental frequency) extraction is important in speech signal processing like speech recognition, speech analysis and synthesis. However the exact pitch extraction from speech signal is very difficult due to the effect of formant and transitional amplitude. So in this paper, the pitch is detected after the elimination of formant ingredients by flattening the spectrum in frequency region. The effect of the transition and change of phoneme is low in frequency region. In this paper we proposed the new flattening method of log spectrum and the performance was compared with LPC method and Cepstrum method. The results show the proposed method is better than conventional method.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.11
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• pp.5025-5032
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• 2012

The purpose of this study is to compare the working memory and the phonological awareness between Children with multi-cultural families and general families. The research subjects were 15 multi-cultural and 15 general primary school students who were attending 1st-3rd grade in D city. Working memory tested K-TTFC-2 by standardized tool. Phonological awareness abilities was considering the age of the subjects, tested phoneme awareness. Data process was conducted by t -test and frequency test in SPSS program. The results were as follows. First, working memory comparison of both groups showed significant differences. Especially had significant difference in chapter 1, chapter 4. Second, comparison of phonological awareness between both groups showed significant statistic differences. Third, the Phonological awareness comparison of both groups showed that there are differences in sound matching(word medial coda), substituting middle sound in monosyllabic words, phoneme switching. This research result is considered that can be used as the fundamental data for the development of the therapy data considering the working memory and the phonological awareness of children with multi-cultural families.

• KIISE Transactions on Computing Practices
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• v.22 no.11
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• pp.591-600
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• 2016

Computing technologies are increasingly applied to most casual human environment networks, as computing technologies are further developed. In addition, the rapidly increasing interest in IoT has led to the wide acceptance of speech recognition as a means of HCI. In this study, we present a novel method for recognizing the Korean vowel 'ㅜ', as a part of a phoneme based Korean speech recognition system. The proposed method involves analyses of bulk indicators calculated in the time domain instead of analysis in the frequency domain, with consequent reduction in the computational cost. Four elementary algorithms for detecting typical waveform patterns of 'ㅜ' using bulk indicators are presented and combined to make final decisions. The experimental results show that the proposed method can achieve 90.1% recognition accuracy, and recognition speed of 0.68 msec per syllable.

• Proceedings of the Korea Multimedia Society Conference
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• 1998.10a
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• pp.221-225
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• 1998

본 논문에서는 연속분포(Continuous) HMM(hidden Markov model)을 기반으로 하여 한국어 고립단어인식 시스템을 설계, 구현하였다. 시스템의 학습과 평가를 위해 자동차 항법용 음성 명령어 도메인에서 추출한 10개의 고립단어를 대상으로 음성 데이터 베이스를 구축하였다. 음성 특징 파라미터로는 MFCCs(Mel Frequency Cepstral Coefficients)와 차분(delta) MFCC 그리고 에너지(energy)를 사용하였다. 학습 데이터로부터 추출한 18개의 유사 음소(phoneme-like unit : PLU)를 인식단위로 HMM 모델을 만들었고 조음 결합 현상(채-articulation)을 모델링 하기 위해 트라이폰(triphone) 모델로 확장하였다. 인식기 평가는 학습에 참여한 음성 데이터와 학습에 참여하지 않은 화자가 발성한 음성 데이터를 이용해 수행하였으며 평균적으로 97.5%의 인식성능을 얻었다.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.86-91
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• 1999

본 논문에서는 유성/무성/묵음 분류기와 주파수 스펙트럼 비교를 통하여 음소 경계 검출기를 구현하였다. 음소경계 검출은 음성 인식, 합성 및 분석 둥의 분야에서 매우 중요하다 유성/무성/묵음 분류기를 이용하여 유성음으로 판별되는 구간은 스펙트럼 비교를 통하여 음소 단위로 세분하였고 무성음으로 판별되는 구간은 한국어의 음성 특성을 고려하여 하나의 음소 단위로 간주하였다. 유성음 구간에 대한 스펙트럼 비교는 수정된 Itakura-Saito distance measure 와 Euclidean MFCC(Mel Frequency Cepstrum Coeffcients) distance measure를 사용하였고 비교 프레임은한 프레임을 건너 윈 경우가 가장 결과가 좋았다. 최종적으로 평균 음소 길이 정보를 이용하여 음소의 경계로 검출된 구간을 더 세분하거나 통합하였다. 유성/무성/묵음 분류기의 경우는 사무실에서 녹음한 고립단어에 대하여 $94.247\%$의 정확도를 보였고 음소 경계 검출의 경우는 $72.8\%$의 정확도를 보였다.

• Proceedings of the Korean Information Science Society Conference
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• 2000.04b
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• pp.357-359
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• 2000

음소 단위로 구축된 음성 데이터는 음성인식, 합성 및 분석 등의 분야에서 매우 중요하다. 일반적으로 음소는 유성음과 무성음으로 구분되어 진다. 이러한 유성음과 무성음은 많은 특징적 차이가 있지만, 기존의 음소 경계추출 알고리즘은 이를 고려하지 않고 시간 축을 기준으로 이전 프레임과 매개변수 (스펙트럼) 비교만을 통하여 음소의 경계를 결정한다. 본 논문에서는 음소 경계 추출을 위하여 유성음과 무성음의 특징적 차이를 고려한 블록기반의 Branch 알고리즘을 설계하였다. Branch 알고리즘을 사용하기 위한 스펙트럼 비교 방법은 MFCC(Mel-Frequency Cepstrum Coefficient)를 기반으로 한 거리 측정법을 사용하였고, 유성음과 무성음의 구분은 포만트 주파수를 이용하였다. 실험 결과 3~4음절 고립단어를 대상으로 약 78%의 정확도를 얻을수 있었다.

• Proceedings of the IEEK Conference
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• 2002.06d
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• pp.381-384
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• 2002

In speech signal processing, it Is very important to detect the pitch exactly in speech recognition, synthesis and analysis. but, it is very difficult to pitch detection from speech signal because of formant and transition amplitude affect. therefore, in this paper, we proposed a pitch detection using the spectrum flattening techniques. Spectrum flattening is to eliminate the formant and transition amplitude affect. In time domain, positive center clipping is process in order to emphasize pitch period with a glottal component of removed vocal tract characteristic. And rough formant envelope is computed through peak-fitting spectrum of original speech signal in frequency domain. As a results, well get the flattened harmonics waveform with the algebra difference between spectrum of original speech signal and smoothed formant envelope. After all, we obtain residual signal which is removed vocal tract element The performance was compared with LPC and Cepstrum, ACF 0wing to this algorithm, we have obtained the pitch information improved the accuracy of pitch detection and gross error rate is reduced in voice speech region and in transition region of changing the phoneme.

• Journal of the Korean Institute of Telematics and Electronics
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• v.25 no.12
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• pp.1503-1512
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• 1988

As the basic analysis to solve the within-and cross-speaker variability in phoneme based speech recognition, changes in pitch and formant frequencies of 8 Korean vowels with age and sex of speaker has been investigated by analyzing a large number fo samples. Conclusions obtained are as follows: 1) Changes in pitch frequency with age and sex of speaker for children are hard to distinguish and the difference of before and after the voice change is analyzed approximately 0.2 oct. for female an 0.9 oct. for male. 2) While most of the formants of vowel considerably change with the age of speaker, the change becomes smaller as the age becomes older. 3) While there is an indirect correlation between pitch and formant with change in age, it is hard to see a direct correlation. 4) When the objects of the recognition experiment by pitch and formants are various speakers in each age and sex, pitch also works as an efficient recognition parameter.