• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.21-24
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• 2008

The present study numerically investigates the glottal airflow characteristics as well as acoustic features of phonation fully coupled with dynamic behavior of vocal folds. The vocal folds are described by a low-dimensional body-covered model characterized by bio-mechanical parameters such as glottal width, vocal folds stiffness, and subglottal pressure. The flow in the vocal tract is modeled as an incompressible, axisymmetric form of the Navier-Stokes equations (INS), while the acoustic field is predicted by the linearized perturbed compressible equations (LPCE). The computed result shows that a two-mass model of vocal folds is sufficient to reproduce temporal variations in oral airflow and glottis motion produced by female speakers. It is also found that i) the glottal width has a significant effect on the amplitude of glottal flow, and thus on the amplitude of acoustic wave in the vocal tract, ii) the vocal fold tension is the main control parameter for the fundamental frequency of phonation, iii) the subglottal pressure plays an appreciable role on reproduction of the self-sustained oscillation of vocal folds, and iv) the strength of pulsating airflow and vortical structures are primarily affected by glottal width and subglottal pressure, and are closely related to pitch, loudness, and voice quality. Finally, more comprehensive explanation about the difference between one- and two-mass models is presented with discussion of effectiveness of vocal folds oscillation and voice quality.

• Speech Sciences
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• v.10 no.1
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• pp.15-25
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• 2003

A laryngograph was developed to measure the open and closed movements of vocal folds in our laboratory. This study attempted to evaluate its performance by comparing its glottal data with that of the original laryngograph. Ten normal Korean adults Participated in the experiment. Each subject produced a sustained vowel /a/ for about five seconds. This study compared f0 values, contact quotients of the duration of closed vocal folds over one glottal pulse, and area quotients of the closed over open vocal folds derived from glottal waves using both the original and new laryngographs. Results showed that the mean and standard deviation of the two laryngographs were almost comparable with a correlation coefficient 0.662 but minor systematic shift below those of the original laryngograph was observed. The absolute mean difference converged into 1 Hz, which indicates a possibility of adopting some threshold of rejecting inappropriate pitch values beyond a threshold value. The contact quotient of the normal subjects came out slightly over the 50% in a citation speech. Finally, the area quotient converged into 1. We will pursue further studies on the abnormal patients in the future.

• Proceedings of the IEEK Conference
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• 2001.09a
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• pp.793-796
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• 2001

음성인식 시스템은 인간의 의사소통 수단인 음성을 기계가 인지할 수 있게 하는 것이다. 이러한 음성 인식 알고리즘 개발은 현재 활발히 진행되고 있다. 올바른 음성인식 시스템의 구현을 위해서는 높은 인식률 구현과 적은 처리시간이 요구된다. 또한 인식률 향상을 위해서는 그 구현 알고리즘이 복잡해지고 이에 따라 많은 처리 시간이 요구된다. 본 논문에서는 성문 특성에 따른 Glottal Spectrum에 적응적인 필터계수를 적용하여 인식률 향상을 도모하였다. 제안한 알고리즘을 모의 실험한 결과 전체 인식률이 2% 향상되었다.

• Proceedings of the KSLP Conference
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• 1996.11a
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• pp.92-92
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• 1996

비디오스트로보스코피 화상의 정량화를 통한 glottal cycle의 객관적인 평가는 여러 질환의 감별 및 치료전후의 결과를 비교하는데 중요한 역할을 담당할 수 있으리라 사려되나 아직은 정상 발성시나 병적인 조건에서의 참고치나 그 의미에 대하여 보고된 경우는 흔치 않은 실정이다. 이에 저자들은 정상성인을 대상으로 발성의 주파수와 강도의 변화에 따른 glottal cycle의 변화를 정량화 함으로써 추후 연구나 임상적용 둥의 기본자료로서 활용하고자 하였다. (중략)

• Phonetics and Speech Sciences
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• v.1 no.4
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• pp.29-38
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• 2009

This study investigated the interaction between consonants and vowels in Korean syllable perception using a speeded classification task (Garner, 1978). Experiment 1 examined whether listeners analytically perceive the component phonemes in CV monosyllables when classification is based on the component phonemes (a consonant or a vowel) and observed a significant redundancy gain and a Garner interference effect. These results imply that the perception of the component phonemes in a CV syllable is not linear. Experiment 2 examined the further relation between consonants and vowels at a subphonemic level comparing classification times based on glottal features (aspiration and lax), on place of articulation features (labial and coronal), and on vowel features (front and back). Across all feature classifications, there were significant but asymmetric interference effects. Glottal feature.based classification showed the least amount of interference effect, while vowel feature.based classification showed moderate interference, and place of articulation feature-based classification showed the most interference. These results show that glottal features are more independent to vowels, but place features are more dependent to vowels in syllable perception. To examine the three-way interaction among glottal, place of articulation, and vowel features, Experiment 3 featured a modified Garner task. The outcome of this experiment indicated that glottal consonant features are independent to both the place of articulation and vowel features, but the place of articulation features are dependent to glottal and vowel features. These results were interpreted to show that speech perception is not abstract and discrete, but nonlinear, and that the perception of features corresponds to the hierarchical organization of articulatory features which is suggested in nonlinear phonology (Clements, 1991; Browman and Goldstein, 1989).

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.18 no.2
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• pp.129-133
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• 2007

Background and Objectives: Nasometry is an easy, noninvasive method to obtain objective data regarding the function of velopharynx. However, because articulation errors may affect the results of nasometry, the examiner should interpret the nasalance score based on appropriate speech stimuli. The purpose of this study is to examine the difference of nasalance score between glottal and oral articulations in patients with velopharyngeal insufficiency (VPI). Materials and Method: Nineteen children between 3.4 and 12.1 years of age (mean age 5.7 years) with a confirmed VPl showing hypernasality and articulation errors (glottal stops) were included. Nasalance scores were obtained for two speech patterns of glottal and oral stops. In addition, the velopharyngeal functions were analyzed in four subjects using video nasopharyngoscopy. Results: The $mean{\pm}S.D$ nasalance scores of the glottal stops and oral stops were $42.54{\pm}16.26%$ and $25.47{\pm}16.51%$ respectively (p=.000). Six of 19 patients achieved normal nasalance scores when glottal stops changed to oral stops by the trial speech therapy. Video nasopharyngoscope confirmed that large velopharyngeal gaps can be decreased into tiny gaps or complete closure when compensatory articulations were corrected for some cases. Conclusion: Compensatory articulation errors must be corrected for the reliable interpretation of the nasalance scores that are obtained in children with velopharyngeal insufficiency, which would facilitate to make a better decision for further management of these patients.

• The Journal of Korean Medicine Ophthalmology and Otolaryngology and Dermatology
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• v.23 no.1
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• pp.182-198
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• 2010

Background : The varieties of manifestations referred to oral, glottal, labial and dental diseases has been long complicated physicians in the efficient diagnosis and treatment of these diseases. Acupuncture has been widely used in Korea throughout the history and provides an efficient method in the treatment of them Objectives : Establish a distinctive and efficient acupuncture method for the treatment of oral, glottal, labial and dental diseases based in literature research Method : We reviewed four Korean medical literature, "Guide to Swollen Sore Treatment", "Treasured Mirror of Eastern Medicine", "Experiential Prescriptions of Acupuncture and Moxibustion", and "Essential Rhymes on Acupuncture and Moxibustion by Master Sa-am", and analyzed the therapeutic characteristics in the treatment of oral, glottal, labial and dental diseases Result : 1. According to "Guide to Swollen Sore Treatment", we could noted frequent application of blood letting methods in the affected area, then rinse ones mouth with salty water and further application of taro plaster. Also found acupuncture methods utilizing heated mole cricket or silkworm in the sublingual region. Regarding herbal method, Realgar was rubbed in the affected area. Mainly used acupuncture points in the treatment of oral, glottal, labial and dental diseases were GV20, GB20, LU5, and auricular anterior hairline 2. In "Treasured Mirror of Eastern Medicine", blood letting method in the sublingual region and burning needle searing method were the most frequently applied in the treatment of oral, glottal, labial and dental diseases. Moxibustion was also applied in the treatment of labial and dental diseases. Particularly, said to apply 3 moxa cones in ear zones of both sides, when no medicine is effective. This demonstrates how emphasized the importance of moxibustion in this kind of disease. Mainly used acupuncture points were GV16, CV24, LI4, EX-HN12, and EX-HN13 3. In "Experiential Prescriptions of Acupuncture and Moxibustion", no other methods beside wrist. Superstitious methods like applying moxibustion on the tooth picture drawn on the roofing tile need further confirmation. Mainly used acupuncture points were LI4, ST36, and HT7. 4. "Essential Rhymes on Acupuncture and Moxibustion by Master Sa-am", identified the cause of diseases according to visceral pattern identification. Stomach and Spleen in charge of vocal, lingual, and labial disease, Kidney for dental disease, and further scrutinizing identification according to Liver, Heart, Stomach, Lung, and Kidney manifestations. Used supplementation and draining needling methods of self meridians and other correlating meridians. Conclusions : After previous study on stroke and eye diseases, we could also find various efficient methods according to oral, glottal, labial and dental diseases, through literature research of korean medical classics. This study will concurrently result in establishing distinctive therapeutic method characteristic of Korea.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.8 no.1
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• pp.5-11
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• 1997

To set up an objective basis for the evaluation of the stroboscopic findings, video-strobolaryngoscopic images of vocal fold vibration in 5 female and 5 male normal speakers were analyzed using an image analysis computer program called KSIP(Kay Storoboscopy Image Processing, Kay Elemetrics Corp., NJ, USA). Four consecutive vibratory cycles were compared in comfortable, louder, high-pitched /ee/ phonation for every subject. findings mostly replicated earlier studies including glottal chinks which were observed in most female speakers throughout the cycles and clear distinction between female and male speakers in their vibratory patterns as well as intensity and frequency-re-lated differences. However, there were some findings incompatible with those from previous studies which may be attributable to technical problems. This study may provide an objective basis of the stroboscopic findings such as image shape, amplitude, area, and their changes according to frequency and intensity variations. We anticipate that funker study with larger samples ran provide an objective criteria for normal vibratory characteristics of the laryngostro-boscopic findings.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.12 no.2
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• pp.121-125
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• 2001

Singing requires exquisite coordination between the respiratory and phonatory system to efficiently control glottal airflow. Respiratory function and vocal aerodynamics were investigated in six female professional sopranos and in six female subjects without vocal training. All sopranos had more than 15 years of formal classic vocal training. Pulmonary function test data on simple pulmonary function, flow volume curve, static lung volumes, maximum inspiratory pressure(MIP), and maximum expiratory pressure(MEP) were obtained from all subjects. Vocal aerodynamic studies of maximum phonation time(MPT), phonation quotient, and mean glottal flow rates (MFR) were also measured in all subjects. Simple pulmonary function in professional sopranos was generally the same as that of other female subjects without vocal training. However, MIP and MEP showing respiratory muscle forces were significantly elevated in professional sopranos, compared to those of other female subjects without vocal training. Maximum phonation times and phonation quotient in sopranos are longer than those of other female subjects even though there were no differences in simple pulmonary function. High-pitched tones were made with significantly higher mean glottal flow rates(GFR) in normal subjects than low-pitched tones, whereas no changes in GFR were found in sopranos. The result indicated that sopranos demonstrated significant improvements in aerodynamic measures of GFR, maximum phonation time, suggesting an increase in glottal efficiency.

• Speech Sciences
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• v.11 no.2
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• pp.165-177
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• 2004

Western singers voice have been studied in music science since the early 20th century. However, Korean traditional singers voice have not yet been studied scientifically. This study is to find the physiological and acoustic characteristics of Pansori singers voices. Western singers participated for comparative purposes. Ten western singers and ten Pansori singers participated in this study. The subjects spoke and sung seven simple vowels /a, e, i, o, u, c, w/. An analysis of Glottal image was done by Scope View and acoustic characteristics of speech and singing voice were analyzed by CSL. The results are as follows: (1) Glottal gestures of Pansori singers showed asymmetric vocal folds. (2) Singing vowel formants of Pansori singers showed breathiness based on Spectrogram. (3) Music formant of western singers appeared in around 3kHz area, however, Pansori singers formant appeared in low frequency area. Modulation of vibrato showed 6 frequency per sec in case of western singers. Pansori singers showed no deep modulation of vibrato on spectrogram.