• 대한후두음성언어의학회지
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• 제5권1호
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• pp.44-58
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• 1994

The formants of the 9 Korean standard vowels(which used by the average people of Seoul, central-area of the Korean peninsula) were measured by analysis with the linear predictive coding(LPC) and fast Fourier transform(FFT). The author already had reported the constriction area for the Korean standard vowels, and with the existing data, the distance from glottis to the constriction area in the vocal tract of each vowel was newly measured with videovelopharyngograms and lateral Rontgenograms of the vocal tract. We correlated the formant frequencies with the distance from glottis to the constriction area of the vocal tract. Also we tried to correlate the formant frequencies with the position of tongue in the vocal tract which is divided into 2 categories : The position of tongue in oral cavity by the distance from imaginary palatal line to the highest point of tongue and the position in pharyngeal cavity by the distance from back of tongue to posterior pharyngeal wall. This study was performed with 10 adults(male : 5, female : 5) who spoke primary 9 Korean standard vowels. We had already reported that the Korean vowel [i], [e], $[{\varepsilon}]$ were articulated at hard palate level, [$\dot{+}$], [u] were at soft palate level, [$\wedge$] was at upper pharynx level and the [$\wedge$], [$\partial$], [a] in a previous article. Also we had noted that the significance of pharyngeal cavity in vowel articulation. From this study we have concluded that ; 1) The F$_1$ is related with the oral cavity articulated vowel [i, e, $\varepsilon$, $\dot{+}$, u]. 2) Within the oral cavity articulated vowel [i, e, $\varepsilon$, $\dot{+}$, u] and the upper pharynx articulated vowel [o], the F$_2$ is elevated when the diatance from glottis to the constriction area is longer. But within the lower pharynx articulated vowel [$\partial$, $\wedge$, a], the F$_2$ is elevated when the distance from glottis to the constriction area is shorter. 3) With the stronger tendency of back-vowel, the higher the elevation of the F$_1$ and F$_2$ frequencies. 4) The F$_3$ and F$_4$ showed no correaltion with the constriction area nor the position of tongue in the vocal tract 5) The parameter F$_2$- F$_1$, which is the difference between F$_2$ frequency and F$_1$ frequency showed an excellent indicator of differenciating the oral cavity articulated vowels from pharyngeal cavity articulated vowels. If the F$_2$-F$_1$ is less than about 600Hz which indicates the vowel is articulated in the pharyngeal cavity, and more than about 600Hz, which indicates that the vowel is articulated in the oral cavity.

• 말소리와 음성과학
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• 제14권2호
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• pp.55-65
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• 2022

본 연구에서는 남성 뮤지컬 전공 학생의 발성 시 고, 중, 저의 후두 높이 조건에 따른 음향학적 측정치를 비교하고자 하였다. 또한 휴식 시 후두 융기의 높이를 기준으로 후두의 상대적 높이와 음향학적 측정치 간의 상관관계를 알아보고, 후두의 상대적 높이에 대한 예측 가능성을 확인하고자 하였다. 연구대상은 남성 뮤지컬 가창 전공 남학생 5명이었으며, 고, 중, 저의 후두 위치에서 발성한 /아/ 모음을 각각 10회씩 발성하도록 하여 음향학적 분석을 시행하였다. 발성 시, 휴식 시를 기준으로 고, 중, 저 위치에서의 후두 융기의 상대적 수직 위치를 측정하였다. 연구 결과, 후두의 상대적 위치는 휴식 시를 기준으로 유의한 차이가 있었다. 후두가 하강함에 따라 포먼트 주파수는 감소한 반면, 해당 주파수에서의 스펙트럼 에너지는 증가하였다. 포먼트 주파수는 후두의 상대적 높이와 약함-중간 수준의 정적 상관관계를, 스펙트럼 에너지는 중간 수준의 부적 상관관계를 보였다. 후두의 상대적 높이는 8개의 음향학적 측정치에 의해 예측되었다(수정된 R²=.829). 이를 통하여 비침습적인 방법으로 후두의 상대적 높이를 예측할 수 있는 가능성을 일부 확인하였다.

• 음성과학
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• 제13권4호
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• pp.69-87
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• 2006

This study aims to describe the vowel system of present-day American English and to discuss some of its phonetic variations due to regional differences. Fifteen speakers of American English from various regions of the United States produced the monophthongs of English. The vowel duration and the frequencies of the first and the second formant were measured. The results indicate that the distinction between the vowels [c] and [a] has been merged in most parts of the U.S. except in some speakers from eastern and southeastern parts of the U.S., resulting in the general loss of phonemic distinction between the vowels. The phonemic merger of the two vowels can be interpreted as the result of the relatively small functional load of the [c]-[a] contrast, and the smaller back vowel space in comparison to the front vowel space. The study also shows that the F2 frequencies of the high back vowel [u] were extremely high in most of the speakers from the eastern region of the U.S., resulting in the overall reduction of their acoustic space for high vowels. From the viewpoint of the Adaptive Dispersion Theory proposed by Liljencrants & Lindblom (1972) and Lindblom (1986), the high back vowel [u] appeared to have been fronted in order to satisfy the economy of articulatory gesture to some extent without blurring any contrast between [i] and [u] in the high vowel region.

• 말소리와 음성과학
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• 제3권4호
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• pp.45-53
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• 2011

Flemming and Johnson (2007) claim that there is a fundamental distinction between the mid central vowel [ə] and the high central vowel [?] in that [ə] occurs in an unstressed word-final position while [?] appears elsewhere. Compared to English counterparts, Korean [ə] and [?] are full vowels and they have phonemic contrast. The purpose of this paper is to explore the acoustic quality of two English reduced vowels produced by Korean learners and native speakers of English in terms of their two formant frequencies. Sixteen Korean learners of English and six native speakers of English produced four types of English words and two types of Korean words with different phonological and morphological patterns. The results show that Korean learners of English produced the two reduced vowels of English and their Korean counterparts differently in Korean and English words.

• 대한음성학회지:말소리
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• 제56호
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• pp.173-183
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• 2005

We propose a speech emotion recognition method for affective human-robot interface. In the Proposed method, emotion is classified into 6 classes: Angry, bored, happy, neutral, sad and surprised. Features for an input utterance are extracted from statistics of phonetic and prosodic information. Phonetic information includes log energy, shimmer, formant frequencies, and Teager energy; Prosodic information includes Pitch, jitter, duration, and rate of speech. Finally a pattern classifier based on Gaussian support vector machines decides the emotion class of the utterance. We record speech commands and dialogs uttered at 2m away from microphones in 5 different directions. Experimental results show that the proposed method yields $48\%$ classification accuracy while human classifiers give $71\%$ accuracy.

• 대한전자공학회논문지
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• 제25권4호
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• pp.430-436
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• 1988

LSF(Line Spectral Frequency) derived from LPC has known as a very useful transmission parameter of speech signals, for it has a good linear interpolation characteristics and a low spectrum distortion at low bit rates coding. This paper presents that it is possible to extract directly the formant frequencies of speech signals from LSF parameter without application of FFT algorithm by comparing the distribution of LSF parameter with the frequency distribution of analysis filter. This paper suggests the advanced algorithm that results in improving the speed of convergence at analytic solution method. Also, for the flexibility of parameters, the process that transforms from LSF to LPC is presented.

• 말소리와 음성과학
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• 제7권1호
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• pp.11-17
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• 2015

This paper deals with the correlation between physical fatigue and speech signals. A treadmill task to increase fatigue and a set of subjective questionnaire for rating tiredness were designed. The results from the questionnaire and the collected bio-signals showed that the designed task imposes physical fatigue. The t-test for two-related-samples between the speech signals and fatigue showed that the parameters statistically significant to fatigue are fundamental frequency, first and second formant frequencies, long term average spectral slope, smoothed pitch perturbation quotient, relative average perturbation, pitch perturbation quotient, cepstral peak prominence, and harmonics to noise ratio. According to the experimental results, it is shown that mouth is opened small and voice is changed to be breathy as the physical fatigue accumulates.

• 대한음성학회:학술대회논문집
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• 대한음성학회 2006년도 춘계 학술대회 발표논문집
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• pp.63-66
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• 2006

This present study investigates the vowels in Bahasa Malaysia and Bahasa Indonesia in terms of the first two formant frequencies. For this study, we recruited 30 male native speakers of Bahasa Malaysia and Bahasa Indonesia (15 each) which include 6 vowels (i, e, a, o, u, a) in various contexts. The present study provides a three-dimensional vowel space by plotting F1, F2, and the frequency of datapoints. This study is significant in that the geophysics of vowel space presents yet another view of the vowel space.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.441-445
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• 2009

We have developed a real-time software tool to extract a speech feature vector whose time sequences consist of three groups of vector components; the phonetic/acoustic features such as formant frequencies, the phonemic features as outputs on neural networks, and some distances of Japanese phonemes. In those features, since the phoneme distances for Japanese five vowels are applicable to express vowel articulation, we have designed a switch, a volume control and a color representation which are operated by pronouncing vowel sounds. As examples of those vowel interface, we have developed some speech training tools to display a image character or a rolling color ball and to control a cursor's movement for aurally- or vocally-handicapped children. In this paper, we introduce the functions and the principle of those systems.

• 한국통신학회논문지
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• 제14권6호
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• pp.699-712
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• 1989

본 論文에서는 포르만트 VOCODER를 구성하여 한국어 음성합성에 대한 연구를 보고하였다. 음성 합성 파라메터로서는 1) 스펙트럼 모멘트법으로 구한 포르만트 F1, F2, F3 및 평균성도 길이에서 설정한 F4, F5. 2) AMDF를 이용한 최적 Comb법으로 구한 피치 주파수, 3) 단시간 평균에너지와 단시간 평균 진폭 4) Fant가 발표한 포르만트 주파수에서 대역폭 결정식, 5) 단시간 영교차율에 의한 유/무성 결정. 6) Rosenberg가 제시한 음원파형. 7) 가우시안 백색잡음원이다. 합성 결과는 원음성과 매우 잘 일치함을 보였다.