• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.1
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• pp.333-342
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• 2012

This paper presents a vowel onset point (VOP) detection method based on the human auditory system. This method maps the "perceptual" frequency scale, i.e. Mel scale onto a linear acoustic frequency, and then establishes a series of Triangular Mel-weighted Filter Bank simulate the function of band pass filtering in human ear. This nonlinear critical-band filter bank helps greatly reduce the data dimensionality, and eliminate the effect of harmonic waves to make the formants more prominent in the nonlinear spaced Mel spectrum. The sum of mel spectrum peaks energy is extracted as feature for each frame, and the instinct at which the energy amplitude starts rising sharply is detected as VOP, by convolving with Gabor window. For the single-word database which contains 12 vowels articulated with different kinds of consonants, the experimental results showed a good average detection rate of 72.73%, higher than other vowel detection methods based on short-time energy and zero-crossing rate.

• Proceedings of the Acoustical Society of Korea Conference
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• spring
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• pp.127-130
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• 2002

본 연구에서는 우리말 연속 숫자음 인식에서 본래의 숫자음을 변이 시키는 주된 요인인 연음현상에 대한 인식을 높이기 위해 별도의 연음부분의 레퍼런스를 작성하여 매칭 시키는 방식을 제안한다 또한 단모음으로 이루어진 /2/와 /5/의 연속된 음에 대하여도 레퍼런스를 작성하였다. 제안한 방식에 의하여 전체적으로 $1.4\%$정도 인식률이 상승됨을 볼 수 있다. 특히 발성 목록중 /82/, /62/, /31/, /15/, /75/ 등의 연음과 /226/, /755/등과 같이 모음의 연속된 발성이 포함된 숫자 열에서 제안된 방식이 인식률에 영향을 미치는 것을 볼 수가 있었다. 이는 연음에서 발생하는 오류가 연속 숫자음에 많은 영향을 미치는 것을 알 수 있다. 그 외에 /22/, /55/등과 같이 단모음으로 이루어진 숫자음의 연속 발성 또한 인식률을 저하시키는데 한 요인으로 작용함으로서 이에 대한 레퍼런스도 작성하여 인식률이 상승되는 것을 볼 수 있었다.

• Phonetics and Speech Sciences
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• v.12 no.1
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• pp.85-95
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• 2020

Sentence repetition is a way of evaluating speech sound production to improve the limitation of word tests and spontaneous speech analysis. Speech sounds produced by children can be evaluated using several indicators. This study examined the progression of the percentage of correct consonants-revised (PCC-R) and phonological whole-word measure in different age and gender groups after setting consonants in various vowel contexts and implementing sentence repetition tasks that were designed to give all phonemes the chance to appear at least three times. For this study, 11 sentence repetition tasks were applied to 535 children aged 3 to 7 across the country, after which the resulting PCC-R and whole-word measure were analyzed. The study results showed that all the indicators improved in older age groups and there were significant differences depending on age, however, no significant differences dependent on gender were found. The sentence repetition conditions data used in this study were collected from across the country, and the age difference between each age group was six months. This study is noteworthy because it collected a sufficient amount of data from each group, highlighted the limitation of the word naming and the spontaneous speech analysis, and suggests new criteria of evaluation through the analysis of each whole-word measure in sentence repetition, which was not applied in previous studies.

• The Journal of the Korea Contents Association
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• v.21 no.10
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• pp.603-612
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• 2021

The purpose of this study is to allow beginner level English learners to experience the English speaking task using pictures, and to analyze the meanings of the experience using a phenomenological research method. As research participants, 10 freshmen majoring in Power Generation Facilities at Korean Polytechnic University in Gangwon-do were selected. Face-to-face interviews and SNS were used for data collection, and Colaizzi's research method was adopted for data analysis. As a result of the analysis, 9 themes, 4 theme clusters, and 2 categories were derived. The results are as follows. First, the participants were able to find hope that they could speak English at their own level through the English speaking task using pictures. Second, they stated that the effect of the visual medium of painting increased concentration and curiosity and lowered anxiety. Third, it was recognized that self-confidence, a speaker like a native speaker, and quickness of speaking improved due to familiarity with speaking English. Fourth, the biggest difficulty in the English speaking task was vocabulary. So, they felt the limitation in explaining the picture, and they were having a lot of trouble in translating Korean words into English words. Finally, through the results of this study, the effect of the medium of picture was confirmed, and necessary future studies were suggested.

• Phonetics and Speech Sciences
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• v.13 no.2
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• pp.91-101
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• 2021

The purpose of this study was to investigate laryngeal characteristics in children with autism spectrum disorders (ASD). A total of 50 children participated, including eight children aged 2 to 4 years old diagnosed with ASD and 42 normal controls at the same age. All children recorded X-ray images of the midsagittal plane of the cervical spine and larynx, and compared the laryngeal positions of ASD and control. In addition, samples of children with vowel prolongation were collected and analyzed for acoustic parameters. X-rays showed that the height of the hyoid bone in the normal group was the lowest at 3 years of age, and ascended at 4 years of age. Nevertheless, the distance from the external acoustic meatus to the hyoid bone was longest at age 4. 4-year-olds with explosive language development showed laryngeal height elevation and anteriorization. In contrast, the hyoid height of the ASD group of all ages was lower than that of the control group, and there was no difference in the hyoid position between the ages. As a result of acoustic evaluation, PFR, vFo, and vAm were significantly higher ASD than control. Low laryngeal height of ASD children may be associated with delayed language development. PFR, vFo, and vAm seem to be voice markers showing the difference between normal and ASD children.