• 대한청각학회지
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• 제25권3호
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• pp.124-130
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• 2021

Background and Objectives: The study investigated vowel context effects on the perception of stop consonants in Malayalam. It also probed into the role of vowel context effects in determining the frequency of occurrence of various consonant-vowel (CV) syllables in Malayalam. Subjects and Methods: The study used a cross-sectional pre-experimental post-test only research design on 30 individuals with normal hearing, who were native speakers of Malayalam. The stimuli included three stop consonants, each spoken in three different vowel contexts. The resultant nine syllables were presented in original form and five gating conditions. The consonant recognition in different vowel contexts of the participants was assessed. The frequency of occurrence of the nine target syllables in the spoken corpus of Malayalam was also systematically derived. Results: The consonant recognition score was better in the /u/ vowel context compared with /i/ and /a/ contexts. The frequency of occurrence of the target syllables derived from the spoken corpus of Malayalam showed that the three stop consonants occurred more frequently with the vowel /a/ compared with /u/ and /i/. Conclusions: The findings show a definite vowel context effect on the perception of the Malayalam stop consonants. This context effect observed is different from that in other languages. Stop consonants are perceived better in the context of /u/ compared with the /a/ and /i/ contexts. Furthermore, the vowel context effects do not appear to determine the frequency of occurrence of different CV syllables in Malayalam.

• 말소리와 음성과학
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• 제7권1호
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• pp.39-45
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• 2015

Changes in speech production in normal elderly might be subtle and gradual. Therefore, an acoustic analysis is appropriate to identify the effect of aging on speech. For this purpose, this study examined four speech parameters; voice onset time (VOT), VOT range, $f_0$ of following vowel($f_0FV$), and $f_0FV$ difference in two age groups, old (mean age 74.57 yrs.) and young (m: 27.43 yrs.). The results show that compared to the older group the younger demonstrated significantly shorter VOTs in lenis and longer in aspirated stop. VOT ranges were relatively broad and consequently overlapped between the phonation types (e.g., lenis, fortis, aspirated). The $f_0FV$ values in the older group which are an integral parameter with VOT were lower compared with the young group. The $f_0FV$ differences in the old female group were significantly narrower than the young female group, therefore, clear distinction became difficult. In conclusion, contrast in temporal information was obscured, and the domain of glottal information was diminished on stop consonants in Korean elderly. The findings suggest that central/peripheral changes by aging could lead to a deficit in coordination between phonation and articulation.

• 음성과학
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• 제7권1호
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• pp.53-64
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• 2000

Theoretically, alaryngeal speakers have difficulty in accomplishing the production of voiceless consonants. However, the perceptual studies often reveal a clear production of voiceless consonants giving good articulation scores in skilled alaryngeal speakers. The purpose of the present study was to clarify the production of voiceless stops in mode of articulation to normal speakers and skilled alaryngeal speakers. The acoustic characteristics of alaryngeal speech compared to the normal speech were investigated with special reference to the voiceless stop consonants. The surface electromyography from neck is used to monitor pharyngeal activity during speech. The general result is. that esophageal, shunt and neoglottal speakers realize the distinctions between the three types of [p] in a manner parallel to normals, whereas those using an electric voice generator do not.

• 한국안전학회지
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• 제26권4호
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• pp.14-19
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• 2011

Conveyors cause a high serious and fatal injuries in the industry. Every year people are hurt or killed as a result of accidents on conveyors. Most accidents occur during operation and maintenance when employees are working on moving, unguarded conveyors or when the conveyors starts unexpectedly. In 2008 there were 486 reported injures ranging from fatalities to injures. Of these 486 reported accidents, 8 were fatalities, 66.9%(325) of reported accidents occurred in manufacturing company and 43.8%(213) occurred at the belt conveyors. The objective of this study was to invent the remote emergency stop device because industrial accidents mainly occur at blind spots where usually do not have any safety guard or device rather than the normal working places. In principle, this new device will use with the existing safety system. Then, it will be powerful safety system for preventing injuries related with conveyors.

• 한국콘텐츠학회논문지
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• 제10권8호
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• pp.95-103
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• 2010

디지털 카메라의 센서는 각각의 픽셀에 대응하는 휘도 값을 저장한 것이다. 이러한 상태의 기록을 로파일이라고 한다. 로파일은 가장 밝은 하이라이트 한 스톱부터 이미지가 갖는 레벨 값의 절반을 할당하고 그 나머지의 절반을 그 다음 스톱에 할당하는 방식으로 가장 어두운 섀도에는 가장 적은 레벨을 분배하는 특성을 갖는다. 그러므로 가장 많은 레벨 정보를 갖고 있는 가장 밝은 하이라이트 한 스톱을 촬영 시 반드시 확보하면 디지털 카메라의 향상된 화질을 구현할 수 있을 것이다. 즉 이러한 디지털 이미지의 정보 기록 분배 방식으로 인하여 촬영 시 노출이 매우 중요하다고 판단할 수 있다. 본 논문은 디지털 카메라의 최적노출을 위하여 가장 많은 레벨 값이 할당되는 하이라이트 한 스톱을 가능한 한 최대한도로 유지하기 위하여 얼마만큼의 노출 과다 조정과 감도가 효과적인지 실험을 통하여 밝혀냈다. 이를 위하여 디지털 카메라를 적정 노출에서부터 1/3스톱씩 2스톱까지 7단계의 노출 과다로 촬영하고 적정 노출을 기준으로 노출이 과다된 로파일을 노출 부족으로 컨버팅 하여 화질을 향상시키는 ETTR(Exposure to the right) 노출 방법의 효용성을 검증하였다. 그 결과 다이내믹 레인지를 확장시키고 비주얼 노이즈를 최소화시키는 디지털 카메라의 최적 화질 구현을 위하여 가장 적정한 노출은 약 $1\frac{2}{3}$ 스톱 정도 노출을 과다하였을 때이며 고감도로 갈수록 그 효과가 높았다. 이와 같은 논문은 카메라 사용자와 제조사에게 실용적인 ETTR 노출 정보를 제공함으로써 넓은 다이내믹 레인지를 구현하는 동시에 노이즈를 최소화시켜 최적화된 디지털 카메라의 화질 구현할 수 있게 할 것이다.

• 말소리와 음성과학
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• 제7권2호
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• pp.19-28
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• 2015

This study investigated final consonant error characteristics at word-medial position in children with functional articulation disorder. Data was collected from 11 children with functional articulation and 11 normal children, ages 4 to 5. The speech samples were collected from a naming test. Seventy-five words with every possible bi-consonants matrix at the word-medial position were used. The results of this study were as follows : First, percentage of correct word-medial final consonants of functional articulation disorder was lower than normal children. Second, there were significant differences between two groups in omission, substitution and assimilation error. Children with functional articulation disorder showed a high frequency of omission and regressive assimilation error, especially alveolarization in regressive assimilation error most. However, normal children showed a high frequency of regressive assimilation error, especially bilabialization in regressive assimilation error most. Finally, the results of error analysis according to articulation manner, articulation place and phonation type of consonants of initial consonant at word-medial, both functional articulation disorder and normal children showed a high error rate in stop sound-stop sound condition. The error rate of final consonant at word-medial position was high when initial consonant at word-medial position was alveolar sound and alveopalatal sound. Futhermore, when initial sounds were fortis and aspirated sounds, more errors occurred than linis sound was initial sound. The results of this study provided practical error characteristics of final consonant at word-medial position in children with speech sound disorder.

• 대한후두음성언어의학회지
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• 제17권2호
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• pp.98-102
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• 2006

Background and Objectives : Voice onset time(VOT) is defined as the time interval from oral release of a stop consonant to the onset of glottal pulsing in the following vowel. VOT is a temporal characteristics of stop consonants that reflects the complex timing of glottal articulation relative to supraglottal articulation. Stop consonants are characterized by creation of a pressure difference across a complete occlusion in the vocal tract, followed by a sudden release 'burst' due to opening that occlusion. The objects of this study is to evaluate a usefulness of voice onset time in the assessment of voice disorderd patients. Subjects : Subjects were 20 adults with normal voice and with benign laryngeal disorders. Subjects with voice disorders represented the following vocal pathologies : vocal polyp, vocal nodule, Reinke's edema and unilateral vocal fold paralysis(UVFP). Control subjects were matched for age (21-40 yews old) and sex(male) with the voice disorders subjects and had normal vocal qualities with no history of voice disorders. Methods : Each voice-disordered and matched control subject read the test passages containing three types of Korean bilabial consonants. VOT measures were made for the initial $/p/p^h/\;and\;/p'/$. VOT was measured using acoustic waveform or wide band spectrogram. Results : For each voiceless stop consonants, there was a significant difference in VOT between the voice disordered and normal subjects. The mean VOTs of the lax stops in UVFP was significantly shorter than those of control subjects in the UVFP. The mean VOTs of the aspirated stops in the vocal polyp and nodule were longer than those of control subjects, but not significant. The mean VOTs of the glottalized in voice disordered groups were longer than those of control subjects, and significant statistically in the UVFP. Conclusions : VOT may be a clinically useful acoustic parameter in the assessment of voice disordered patients, especially in the unilateral vocal fold paralysis.

• 대한후두음성언어의학회지
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• 제10권1호
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• pp.50-57
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• 1999

A study to get the data of normal stop consonants production as preliminary study for cleft palate patients was performed. Normal Korean native 21 speakers were pronounced $VCV(V=/a/,C=/P/,/{P^1}/,/P^h/,/t/,/{t^1}/,/{t^h}/,/k/,/{k^1}/,/{k^h}/)$ syllables with natural speech rate and intensity. With intrapharyngeal pressure waveforms by pressure sensor in oropharyngeal cavity, amplitude and time duration of intrapharyngeal pressure were analyzed, and with acoustic waveforms and spectrograms, closure duration and VOT were analyzed. As results, the highest amplitude of intrapharyngeal pressure showed in alveolars and heavily aspirated consonants. Velars and unaspirated consonants were higher than bilabials and slightly aspirated ones each, in intrapharyngeal pressure. Bilabilas, alveolars and velars showed similar rise time of intrapharyngeal pressure build-up, but in decay time and total duration time, bilabials were slightly shorter than alveolars and velars, with no statistic significance. In the aspects of tensity, unaspirated consonants showed the longest rise time, heavily aspirated, the second, and slightly aspirated consonants, the shortest, which were also seen in decay time and total duration time. In closure duration, slightly aspirated consonants had the shortest closure duration, and the heavily aspirated ones, the second, and unaspirated consonants showed the longest. In VOT, heavily aspirated consonants showed the longest, slightly aspirated ones, the second and unaspirated ones showed the shortest.

• 말소리와 음성과학
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• 제7권1호
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• pp.57-65
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• 2015

This study aimed to identify the development pattern of final stop consonant perception using the gating task. Sixty-four subjects participated in the study: 16 children aged 4 years, 16 children aged 5 years, 17 children aged 6 years, and 15 adults. One-syllable words with consonant-vowel-consonant(CVC) structure, mokㄱ-motㄱ and papㄱ-patㄱ were used as stimuli in order to remove the redundancy of acoustic cues in stimulus words, 40ms-length (-40ms) and 60ms-length (-60ms) from the entire duration of the final consonant were deleted. Three conditions (the whole word segment, -40ms, -60ms) were used for this speech perception experiment. 48 tokens (4 stimuli ${\times}3$ conditions ${\times}4$ trials) in total were provided for participants. The results indicated that 5 and 6 year olds showed final consonant perception similar to adults in stimuli, papㄱ-patㄱ and only the 6-year-old children showed perception similar to adults in stimuli, 'mokㄱ-motㄱ. The results suggested that younger typically developing children require more acoustic information to accurately perceive final consonants than older children and adults. Final consonant perception ability may become adult-like around 6 years old. The study provides fundamental data on the development pattern of speech perception in normal developing children, which can be used to compare to those of children with communication disorders.

• 대한후두음성언어의학회지
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• 제11권1호
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• pp.104-112
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• 2000

An evaluation of voice disorder has two methods. One is a perceptual analysis and the other is an acoustic analysis. All of these methods are just focused on sustained vowel. The analysis of conversational speech levels in voice disorder has not been achieved enough. The purpose of the present study is to compare two syllable words and sustained vowel in the vocal polyp patients and normal male speakers and to be applied on the vocal assessment and the voice therapy as a basic data. fifteen male patients with vocal polyp were the subject group. Fifteen healthy male were the control group for this study. The voices of the subject and control group, saved in MDVP of CSL were analyzed by its own analysis program. As a results, in subject group, the voice qualities between the vowel following lenis stop and the sustained vowel had no differences, and the voice qualities were different significantly between the vowel following heavily aspirated stop and the sustained vowel. In the control group the vowel fllowing stops and sustained vowel had also many differences in their voice quality, especially significant between the vowel following glottal stop and e sustained vowel.