• 대한세포병리학회지
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• 제7권1호
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• pp.51-58
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• 1996

The cytologic samples of 26 ovarian cystic lesions from 25 women, aspirated under guide by trans-vaginal ultrasound, were evaluated for clinicopathologic correlation. Clinically 20 women were seeking medical assistance for infertility problems, and trans-vaginal cyst aspiration was done during follow-up of ovulation induction. Among them seven cases were histologically confirmed. Twenty cases of "benign cyst" in cytologic diagnosis were follicullar cyst and two cases of "endometriotic cyst" in cytology were histologically also proven in one case. One false positive diagnosis was given to corpus luteum cyst. It is emphasized that because the cysts are aspirated transvaginally and mature squamous epithelial cells occasionally could be mixed in the sample, attention should be given not to diagnose such cases as mature cystic teratoma. According to this study. ovarian aspiration cytology is useful in the management of cystic ovarian lesions, particularly in young women.

• 한국자동차공학회논문집
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• 제8권6호
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• pp.40-50
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• 2000

In this study, as a means of increasing engine power, turbocharging was applied to the gasoline engine of a light passenger car which was originally naturally aspirated. Also the catalytic convertor was applied to improve the exhaust emission characteristics. The comparison of the performance characteristics between the burbocharged engine with catalytic convertor and the naturally aspirated engine was made over the wide range of operating conditions. The results showed considerable increase of the output performances at full load condition by trubocharging while slight losses were observed at part load conditions.

• 한국자동차공학회논문집
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• 제2권2호
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• pp.103-116
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• 1994

In this study the behavior of engine cooling loss and overall heat transfer coefficient were studied experimentally using naturally aspirated engine and turbo charged engine. Using turbo charging, heat dissipation was increased because of the density of the mixture was increased with increment of inlet air flow rate. Therefore, cooling loss of turbo charged engine is larger than naturally aspirated engine. As taking the measurement of surface temperature of combustion chamber, gas heat transfer coefficient was calculated and found that it has greatly affected to overall heat transfer coefficient. The empirical formula of overall heat transfer coefficient established in order to predict of engine cooling loss and express only as a function of mean piston velocity.

• 음성과학
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• 제6권
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• pp.103-117
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• 1999

This paper suggests that the onset-coda asymmetry found in languages like Korean and others should be dealt with in terms of one acoustic feature rather than other articulatory features, claiming that the acoustic feature involved here is [noise], i.e., 'aperiodic waveform energy'. It determines the structural well-formedness of the languages in question whether a coda ends in [noise] or not, regardless of the intensity, the frequency, and the time duration of the [noise]. Fricatives, affricates, aspirated stops, tense stops, and released stops are all disallowed in the coda position due to the acoustic feature [noise] they, commonly end with if they were, posited in the coda. The proposal implies that the three seemingly separate prohibitions of consonants in the coda position -- i) no fricatives/affricates, ii) no aspirated/tense stops, and iii) no released stops -- are directly correlated with each other. Incorporation of the one acoustic feature [noise] in the feature theory enables us to see that the aspects of onset-coda asymmetry are derived from one single source: ban, of [noise] in the coda.

• 말소리와 음성과학
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• 제4권1호
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• pp.13-20
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• 2012

A lax stop in Korean, one of the three laryngeal contrastive stops, has undergone a sound change in terms of its acoustic properties. Prior production studies described this recent lax stop as being differentiated from tense and aspirated stops primarily by fundamental frequencies (f0). And, the acoustic property of voice onset time (VOT) further separates tense stops from lax and aspirated stops. The current research explores how these two major acoustic parameters of f0 and VOT cue the three stop categories in Korean adult listeners' perception. Thirty-one native speakers of Korean participated in two experimental tasks: categorization judgment and within-category goodness ratings. Two sets of audio stimuli were prepared by synthesizing English and Korean male speakers' CV productions. The findings showed that while f0 cues listeners to lax stops as production patterns would predict, VOT were closely related to listeners' categorization and goodness ratings of lax stops. This suggests that accurate characterizations of the recent lax stop category need to be based on Korean speakers' perceptual behavior as well as production patterns.

• 음성과학
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• 제9권2호
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• pp.13-23
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• 2002

This study examines the effect of laryngeal consonants of Korean on prosodic domain-initial strengthening. Keating, Cho, Fougeron & Hsu (1999), Fougeron & Keating (1996), and Hsu & Jun (1998) found that consonants at the beginnings of larger phrases are more constricted than consonants at the beginnings of smaller phrases. Korean laryngeal consonants pose a counter-example to the general pattern of domain-initial strengthening since tense and aspirated consonants are longer word-medially than word-initially. Previous work on domain-initial strengthening focused on domain-initial consonants at different prosodic domains. This study shows that acoustic cues that are not domain-edge also function to demarcate prosodic structure when the domain-initial consonant is laryngeal: VOT for an aspirated consonant and duration of V2 for a tense consonant.

• 말소리와 음성과학
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• 제13권2호
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• pp.9-17
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• 2021

Voice onset time (VOT) is known to be a primary acoustic cue that differentiates voiced from voiceless stops in the world's languages. While much attention has been given to the sound change of Korean stops, little attention has been given to that of English stops. This study examines VOT of stop consonants as produced by English speakers in comparison to Korean speakers to see whether there is any VOT change for English stops and how the effects of stop, place, gender, and individual on VOT differ cross-linguistically. A total of 24 native speakers (11 Americans and 13 Koreans) participated in this experiment. The results showed that, for Korean, the VOT merger of lax and aspirated stops was replicated, and, for English, voiced stops became initially devoiced and voiceless stops became heavily aspirated. English voiceless stops became longer in VOT than Korean counterparts. The results suggest that, similar to Korean stops, English stops may also undergo a sound change. Since it is the first study to be revealed, more convincing evidence is necessary.

• 음성과학
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• 제15권3호
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• pp.203-217
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• 2008

The number of Asian women immigrants in Korea is getting bigger and it's important to note that their communication problem in Korean causes not only the difficulty of adapting to Korean society but their children's speech-language disorder. To date there is little research on their acoustics characters and articulatory errors. Therefore, this study focuses on acoustic characters and articulatory error patterns of the women immigrants from Japan and Philippine based on the theory of "contrastive analysis". The subjects were 16 Japanese women immigrants(age: 42.5$\pm$4.4) and 14 Philippine women immigrants(age: 31.64$\pm$6.7) and control group consisted of 10 Korean women(age: 28.3$\pm$1.2). Speech and hearing of all subjects and control group were within normal limits. Speech samples were analyzed in a computer using CSL and data analysis was done on FFT widow for F1, F2, F3 of vowels and on wideband spectrogram for VOT of plosives and africatives. The results of this study were like this; For Japanese women immigrants, they had different articulatory patterns of /e/, /a/, /u/, /o/, /$\varepsilon$/, /m/ from those of Koreans and showed articulatory errors on the fortis and aspirated sounds. The reason is Japanese has only two distinctive characters for plosives and affricates; voicing and voiceless. The Philippine women immigrants also showed the same error patterns as the Japanese women immigrants. Especially the errors on aspirated sounds were prominent because their mother tongue has no distinctive characters about aspirated sounds. For vowels, they showed errors of /a/, /o/, /c/.

• 말소리와 음성과학
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• 제9권3호
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• pp.85-91
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• 2017

The present study aimed to investigate the changes of acoustic parameters of the aspirated voice in stroke patients. The eighty-eight subjects diagnosed with cerebro-vascular accident were divided into 32 penetration/aspiration (P/A) and 56 Non-P/A groups according to the videofluroscopic swallowing study (VFSS) results, and 26 control subjects participated. All subjects preformed VFSS and vowel /a/ was recorded three times pre- and post VFSS. Since the variation in the acoustic parameters within a single phonation has been observed, we proposed a delta formula for the acoustic parameters which can reflect the temporal changes of the each parameter in an utterance. We measured from the voice data eight acoustic parameters: fundamental frequency (F0), standard deviation of F0 (F0_SD), Jitter, relative average perturbation (RAP), Shimmer, amplitude perturbation quotient (APQ), harmonic to noise ration (HNR), noise to harmonic ratio (NHR). Then we found parameters which show the meaningful biggest temporal change in an utterance using the suggested delta parameter. Among them, the deltas of shimmer and APQ were significantly different pre- and post VFSS. These deltas of the P/A and the control group were increased after VFSS, while those of the Non-P/A group was descended. The variation patterns of the P/A and the control group were similar but the change width of the P/A group was larger. The large variations in an aspirated phonation of the P/A group are thought to be caused by irregular changes in air resistance due to residual food on the vocal cords.

• 음성과학
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• 제11권2호
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• pp.71-87
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• 2004

Korean has a pair of voiceless fricatives, whose laryngeal manifestation comes in parallel to stops and affricates with a three-way lexical contrast. Prior phonetic studies by Kagaya (1974), Iverson (1983), and Kang (1999, 2000) point out /s/ is associated with multiple characteristics of the larynx shared with not only the lax but also the aspirated series, whereas /s' / carries a laryngeal distinction typical of the tense consonants. The complex dual nature of /s/ is again supported by a psycholinguistic study by Kang (2004), as /s/ was found to interact with /$c^h$/ (17% of the time) as well as /c/ (57%) in speech errors. In addition, a recent work by Cho and Lee (2003) notes an interesting chain shift case in the acquisition of the fricatives. Although they observed a significant phonological pattern between child English and Korean, Cho and Lee's description of acquiring fricatives is far from being precise from the perspective of phonetics. From a longitudinal study of recorded tapes by two children at 1;7-3;8 and 1;7-2;1 respectively, I found that /s' / was usually substituted into tense noncontinuants in young children's early production as predicted, whereas /s/ having both lax and aspirated-like glottal properties revealed a complicated pattern of substitutions into lax, tense, and aspirated noncontinuants with a varying degree of preference relative to the subjects. The current acquisition study supports the previous claims concerning fricatives in other languages, showing that their acquisition comes after stops. Besides, it also notes that Korean fricatives are subject to a series of phonological processes called stopping, affricating, tensifying and palatalizing during the transitional period of phonological development by young children. Moreover, between the two voiceless types, /s/ was acquired earlier than /s'/ as the unmarked segment.