• MALSORI
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• no.45
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• pp.63-77
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• 2003

The purpose of voice color conversion is to change the speaker identity perceived from the speech signal. In this paper, we propose a new voice color conversion algorithm through the formant shifting and the spectrum-tilt modification in the frequency domain. The basic idea of this technique is to convert the positions of source formants into those of target speaker's formants through interpolation and decimation and to modify the spectrum-tilt by utilizing the information of both speakers' spectrum envelops. The LPC spectrum is adopted to evaluate the position of formant and the information of spectrum-tilt. Our algorithm enables us to convert the speaker identity rather successfully while maintaining good speech quality, since it modifies speech waveforms directly in the frequency domain.

• Proceedings of the Korean Information Science Society Conference
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• 2012.06b
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• pp.477-479
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• 2012

개의 발성은 성도의 물리적인 특징에 따라 고유의 특정 포먼트를 만들어 내며 개의 품종에 따라 다른 물리적 특징을 가지므로 개의 발성을 HMM(Hidden Markov Model)으로 모델링하여 개의 품종을 분류하는 연구를 하였다. 주파수 특징은 MFCC(Mel Frequency Cepstral Coefficients) 12차, 에너지 컴포넌트 1차, 델타 13차, 억셀러레이션(Acceleration) 13차, 총 39차 벡터를 사용하였다. 개의 품종 분류에 적합한 HMM 구조의 설계를 위하여 기본 좌우 모델, 좌우 모델, 좌우 모델2, 전후진 모델, 총 4가지를 제안하고 실험하여 성능을 비교분석하였다. 이 중 전후진 모델이 가장 바람직한 모델로 검증 되었다. 본 모델은 다음과 같은 장점을 갖는다. (1) 기본 좌우 모델과 마찬가지로 1~2회 발성을 갖는 데이터가 입력되어도 처음에서 마지막 상태까지의 이동단계가 최소 3번까지 가능하므로 적은 횟수의 발성 데이터도 처리가 가능하다. (2) 다수 반복된 발성 데이터의 신호도 처리가 가능하다. 즉, 본 모델은 상태의 이동이 후진도 가능하므로 5회이상 반복된 발성 데이터의 신호의 처리도 가능하다.

• Phonetics and Speech Sciences
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• v.4 no.4
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• pp.45-52
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• 2012

The purpose of this paper is to measure the first two vowel formants of the ten young female speakers from the Buckeye Corpus of Conversational Speech [1] automatically and then to analyze various potential factors that may affect the formant distribution of the eight peripheral vowels of English. The factors that were analyzed included the place of articulation, the content versus function word information, the syllabic stress information, the location in a word, the location in an utterance, the speech rate of the three consecutive words, and the word frequency in the corpus. The results indicate that the overall formant patterns of the female speakers were similar to those of earlier works. The effects of the factors on the realization of the two formants were also similar to those from the male speakers with minor differences.

• Phonetics and Speech Sciences
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• v.4 no.4
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• pp.29-35
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• 2012

The purpose of this study was to measure the first two vowel formants of the forty male and female speakers (twenty young vs. old male speakers and twenty young vs. old female speakers) from the Buckeye Corpus of Conversational Speech and to examine the vowel formant changes across two generations (younger vs. older). The results indicated that the vowel space of the younger generation (in their thirties or less) shifted to the lower left position compared to those of the older generation (in their forties or more) in both male and female speakers. When the results were compared to those of Peterson & Barney (1952), it appears that differences can be found in the size of the vowel spaces through time.

• Phonetics and Speech Sciences
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• v.7 no.2
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• pp.131-138
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• 2015

The aim of this work is to compare the vowel formants of the ten adult female speakers in their twenties and thirties from the Seoul corpus[7] with those of corresponding Korean male speakers from the same corpus and of American female speakers from the Buckeye corpus[4]. In addition, various linguistic factors that are expected affect the formant frequencies were examined to account for the distribution of the vowel formants. Formant frequencies extracted from the Seoul corpus were also compared to those from read speech. The results showed that the formant distribution of the spontaneous speech was very different from that of the read speech, while the comparison between the female and male speakers was similar in both languages. To a greater or lesser degree, the potential linguistic factors influenced the formant frequencies of the vowels.

• Phonetics and Speech Sciences
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• v.7 no.2
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• pp.95-102
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• 2015

The purpose of this paper is to extract the vowel formants of the ten adult male speakers in their twenties and thirties from the Korean Corpus of Spontaneous Speech [4], also known as the Seoul corpus, and to analyze them by comparing to earlier works on the Buckeye Corpus of Conversational Speech [1] in terms of the various linguistic factors that are expected to affect the formant distribution. The vowels extracted from the Korean corpus were also compared to those of the read Korean. The results showed that the distribution of the vowel formants from the Korean corpus was very different from that of read Korean speech. The comparison with English corpus and read English speech showed similar patterns. The factors affecting the Korean vowel formants were the interviewer sex, the location of the target vowel or the syllable containing it with respect to the phrasal word or utterance and the speech rate of the surrounding words.

• Speech Sciences
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• v.8 no.4
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• pp.221-228
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• 2001

The purpose of this study is to analyze the problems Korean students, having acoustic structure of Korean vowels, have when they pronounce English vowels by measuring formant frequencies. The experimental results show that the pronunciation of English vowels by Korean students is partially influenced by their Korean vowels. There is little distinction between /i/ and /I/, /U/ and /u/ due to the absence of short and long vowels in Korean pronunciation. Also, as observed in typical Korean vowel pronunciation, there is little difference between the F1 values of /$\varepsilon$/ and /$\{\ae}$/ by Korean speakers, resulting in inaccurate English pronunciation. In addition, compared to English native speakers, Korean speakers show the biggest difference in F1 value of /c/. The fact that they make pronunciation of /c/ covering /e/, /$\Lambda$/ and /c/ positions probably accounts for such phenomenon. The results of this experiment show the interference of Korean that occurred in some English vowels by native Korean speakers.

• Speech Sciences
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• v.14 no.3
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• pp.47-57
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• 2007

The aim of this study was to investigate the pitch and formant characteristics of vowels produced by monolingual and bilingual children. We collected sustained phonation of single vowels, /a/, /i/, /u/, from children aged 6 through 10 and compared their acoustic characteristics, fo, F1, F2. Results showed a significant difference between the groups in fo and F1 in the sustained phonation /a/, but not in F2. In the sustained phonation /i/, F2 revealed a significant difference but fo and F1 showed no significant difference. The F2 showed a significant difference in the sustained phonation /u/, but fo and F1 revealed no significant difference between the groups. It is needed to study further on the acoustic characteristics of bilingual children so that we can make a proper language intervention strategy for them.

• Journal of the Korean Institute of Telematics and Electronics B
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• v.28B no.10
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• pp.755-760
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• 1991

In this paper, we propose a new formant locus overlapping method which can effectively enhance a naturalness of synthetic speech produced by ddemisyllable based Korean text-to-speech system. At first, Korean demisyllables are divided into several number of segments which have linear formant transition characteristics. Then, database, which is composed of start point and length of each formant segments, is provided. When we synthesize speech with these demisyllable database, we concatenate each formant locus by using a proposed overlapping method which can closely simulate haman articulation mechanism. We have implemented a Korean text-to-speech system by using this method and proved that the formant loci of synthetic speech are similar to those of the natural speech. Finally, we could illustrate that the resulting spectrograms of proposed method are more similar to natural speech than those of conventional method.

• Phonetics and Speech Sciences
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• v.7 no.3
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• pp.65-72
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• 2015

The purpose of this study is to extract the first two vowel formant frequencies of the forty speakers from the Seoul corpus[8] and to compare them by the age and sex. The results showed that the vowel formants showed similar patterns between male and female speakers. All the vowels in each age group and all the age groups in each vowel had main effects on either of the formant frequencies. Whereas in English, the vowel space of the older age group moved slightly to the upper right side relative to the younger group, the location of the vowel spaces of the Korean vowels were not as consistent.