• Speech Sciences
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• v.9 no.1
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• pp.17-26
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• 2002

Voice onset time (VOT) is defined as the time interval from the oral release of a stop consonant to the onset of glottal pulsing in the following vowel. VOT is a temporal characteristic of stop consonants that reflects the complex timing of glottal articulation relative to supraglottal articulation. There have been many reports on efforts to clarify the acoustical and physiological properties that differentiate the three types of Korean stops, including acoustic, fiberscopic, aerodynamic and electromyographic studies. In the acoustic and fiberscopic studies for stop consonants, the voice onset time and glottal width during the production of stops has been known as the longest and largest in the heavily aspirated type followed by the slightly aspirated type and unaspirated types. The thyroarytenoid and posterior cricoarytenoid muscles were physiologically inter-correlated for differentiating these types of stops. However, a review of the English literature shows that the fine movement of the mucosal edges of the vocal folds during the production of stops has not been well documented. In recent. years, a new method for high-speed recording of laryngeal dynamics by use of a digital recording system allows us to observe with fine time resolution. The movements of the vocal fold edges were documented during the period of stop production using a fiberscopic system of high speed digital images. By observing the glottal width and the visual vibratory movements of the vocal folds before voice onset, the heavily aspirated stop was characterized as being more prominent and dynamic than the slightly aspirated and unaspirated stops.

• Phonetics and Speech Sciences
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• v.9 no.3
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• pp.25-32
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• 2017

Besides their effect on the f0 contour of the following vowel, Korean stops are undergoing a sound change in which a partial or complete consonantal merger on voice onset time (VOT) is taking place between aspirated and lax stops. Many previous studies on sound change have mainly focused on group-normative effects, that is, effects that are representative of the population as a whole. Few systematic quantitative studies of change in adult individuals have been carried out. The current study examines whether the sound change holds for individual speakers. It focuses on inter-speaker and intra-speaker variability on sound change in contemporary Korean. Speech data were collected for thirteen Seoul Korean speakers studying abroad in America. In order to minimize the possible effects of speech production, socio-phonetic factors such as age, gender, dialect, speech rate, and L2 exposure period were controlled when recruiting participants. The results showed that, for nine out of thirteen speakers, the consonantal merger is taking place between the aspirated and lax stop in terms of VOT. There were also intra-speaker variations on the merger in three aspects: First, is the consonantal (VOT) merger between the two stops is in progress or not? Second, are VOTs for aspirated stops getting shorter or not (i.e., the aspirated-shortening process)? Third, are VOTs for lax stops getting longer or not (i.e., the lax-lengthening process)? The results of remarkable inter-speaker and intra-speaker variability indicate a synchronous speech sound change of the stop system in contemporary Korean. Some speakers are early adopters or active propagators of sound change whereas others are not. Further study is necessary to see whether the inter-speaker differences exceed intra-speaker differences in sound change.

• Archives of Plastic Surgery
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• v.36 no.2
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• pp.135-139
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• 2009

Purpose: The use of an autogenous fat graft has become a common procedure in plastic surgery. However, questions remain concerning on the viability of fat cells and preservation method of aspirated fat. The purpose of this study was to examine the viability of fat cells stored at $-20^{\circ}C$ in the freeze for 1 year after harvest from abdominal liposuction. Methods: Eighteen adults (aged 24 to 65 years old, 16 female and 2 male) were recruited for this study. Harvested aspirated fat tissues were obtained by suction - assisted lipectomy and frozen at $-20^{\circ}C$ commercial refrigerator for one year (average 12.5 months). The viability off at cells in specimens were measured after thawing. The numbers of viable cells were measured on a fluorescence microscope after staining with fluorescein diacetate and propidium iodide. GPDH (Glycerol - 3 - phosphate dehydrogenase) activity was measured. Cell culture was done for 3 weeks. Results: There were no viable cells under the fluorescence microscope, no detectable GPDH activity, and no cultured cells. Conclusion: These findings suggest that aspirated fat after frozen storage for one year at $-20^{\circ}C$ freezer is inadequate to reuse.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.3
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• pp.428-434
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• 1996

The practice of oral surgery or other dentistry possesses the danger of causing the loss of foreign bodies used within the oral cavity. If such foreign bodies would be lost, they could enter the viscera through the esophagus or tracheobroncheal tree. Ingestion is four times as frequent as aspiration and 80% to 90% of ingested foreign bodies will pass through the body spontaneously. Once the aspiration or ingestion of foreign bodies is happened, a dental procedure should be discontinued immediately. If symptoms of respiratory distress, including coughing, wheezing, or stridor, are present, a patent airway should be maintained, oxygen administered, and ventilation supported if necessary. The PA chest radiograph will identify the objects in the lung, esophagus, or stomach. Ingested gastrointestinal foreign bodies may be managed by observation, endoscopy, and or surgical intervention and aspirated tracheobroncheal foreign bodies may be managed by bronchoscopy, and or surgical intervention. This case report describes the management of ingested or aspirated foreign bodies happened to the three patients during intraoral treatment. we recommend that the preventive method of ingestion or aspiration of the dental foreign bodies should be performed prior to intraoral treatment and the immedieate measures should be carried out after ingestion or asipiration of it.

• Speech Sciences
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• v.7 no.1
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• pp.109-141
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• 2000

Acoustic and aerodynamic characteristics of Cheju consonants were examined with the focus on the well-known three-way distinction among stops (i.e., lenis, fortis, aspirated) and the two-way distinction between sand s*. Acoustic parameters examined for the stops included VOT, relative stop burst energy, Fo at the vowel onset, H1-H2, and H1-F2 at the vowel onset. For the fricatives s and s*, acoustic parameters were fricative duration, Fo, centroid of the fricative noise, RMS energy of the frication, H1-H2 and Hl-F2 at the onset of the following vowel. In investigating aerodynamics, intraoral pressure and oral flow were included for the bilabial stops. Results indicate that, although Cheju and Korean are not mutually intelligible, acoustic and aerodynamic properties of Cheju consonants are very similar in every respect to those of the standard Korean. Among other findings there are three crucial points worth recapitulating. First, stops are systematically differentiated by the voice quality of the following vowel. Second, stops are also differentiated by aerodynamic mechanisms. The aspirated and fortis stops are similar in supralaryngeal articulation, but employ a different relation between intraoral pressure and flow. Finally, our study suggests that the fricative s is better categorized as 'lenis' than as 'aspirated' in terms of its phonetic realization.

• Phonetics and Speech Sciences
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• v.5 no.4
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• pp.185-193
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• 2013

This study investigates dialectal differences in the acoustic properties of Korean lenis, aspirated, and tense stops Seoul Korean (standard Korean) and Yanbian Korean (spoken in the largest Korean Autonomous Prefecture in China). This production study the main acoustic cues that each dialect uses to mark the laryngeal distinction between the three types of Korean stops. Measurements included VOT, and the initial F0 of the following vowel. Data collected from 10 young Seoul Korean speakers, 10 young Yanbian Korean speakers, and 6 older Yanbian speakers. two key findings: First, aspirated and lenis stops are mainly differentiated by F0 in Seoul Korean, and by $H1^*-H2^*$ in Yanbian Korean. Second, there is no VOT merger between lenis and aspirated stops in Yanbian Korean, whereas there is in Seoul Korean. These results are discussed in terms of the phenomenon of VOT shift and the function of F0t is argued that the function of F0 to substitute for VOT difference as a primary cue for the coding of laryngeal contrast can be predicted by the pitch accent system of the language involved.

• Fire Science and Engineering
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• v.24 no.6
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• pp.98-103
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• 2010

A series of fire experiments have been performed to examine the measurement bias of the bare bead thermocouple widely used in fire testing and analyze the measurement bias of bare bead thermocouple comparing with the measured temperature using the aspirated thermocouple. The measured temperature of the bare bead thermocouple was lower than that of the aspirated thermocouple in the hot upper layer while it showed opposite trends in the upper layer. Also, the bare bead thermocouple showed higher measurement bias in the lower layer rather than upper layer in the compartment fire. The maximum relative percentage error of the bare bead thermocouple against the aspirated thermocouple reached 250% in the present study. The present study points out the need of correction process of the measured temperature by bare bead thermocouple for improving the reliability of the fire tests.

• Phonetics and Speech Sciences
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• v.11 no.4
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• pp.35-43
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• 2019

This study examines the voice onset times (VOTs) of Korean stops produced by Korean learners of English with high language proficiency and long L2 exposure (i.e., Korean-English bilinguals) to assess whether the VOTs of their lax and aspirated stops are merging and, if so, which types of stops are being changed. Thirteen Korean speakers (six female and seven male) who had studied in the USA for more than three to ten years participated. The results show that the speakers in this study with long L2 exposure are participating in the VOT merger, in which VOTs for aspirated stops are reduced while those for lax stops are increased. In other words, change in VOT affects not only aspirated stops but also lax stops. The results indicate that L1 phonetic drift may not be primarily affected by the amount of L2 exposure, and language contact may not be the primary factor triggering a sound change in the Korean stop system. Further study is necessary focusing on the phonetic shift of the "lax" category because it may play a pivotal role in a tonogenetic-like sound change in present-day Korean.

• MALSORI
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• no.47
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• pp.73-84
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• 2003

This study investigates differences in intensity across the three different Korean obstruent types in terms of the RMS amplitude of both the entire section and the first 512 samples of the immediately following vowel in two positions. The results showed that for the utterance initial position the RMS amplitude of both the entire section and the first 512 samples of the vowel was greatest for fortis obstruents, intermediate for aspirated ones, and weakest for lenis ones, with a significant difference between each pair of them. For the intervocalic position, in contrast, the intensity of the entire vowel was greatest for fortis obstruents, intermediate for lenis ones, and weakest for aspirated ones, with no significant difference between the last two groups, whereas the intensity of the first 512 samples of the vowel was greatest for fortis obstruents, intermediate for lenis ones, and weakest for aspirated ones, with a significant difference between each pair of the three groups. This means that the intensity of the earlier part of the vowel functions as a discriminator of Korean obstruents. The positional difference is due to the different behavior of the lenis obstruents in the intervocalic position, such that the intensity build-up is already on its way with voice lead.

• Speech Sciences
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• v.13 no.4
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• pp.51-67
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• 2006

This study examined the acoustic properties of initial stops in Korean, produced by Korean native speakers and English Korean learners. The productions of Korean native speakers were compared with those of beginners and advanced learners of Korean. Fundamental frequency(F0) and Voice Onset Time(VOT) were measured in condition of one or two syllable words, containing word-initial lenis, fortis, and aspirated stops. English Korean Learners showed that they produced stops with relatively shorter VOT and lower F0, compared with those of Korean native speakers. In case of the manner of articulation, English Korean learners have production difficulties in order of lenis stops, aspirated stops, and fortis stops. In regard to the place of articulation, English Korean learners showed production troubles in order of labial stops, velar stops, and alveolar stops. In the experiment of perception, it is hard for English Korean learners to distinguish stops of lenis and aspirated. Therefore, the results of production experiment were almost consistent with those of the perception experiment. Finally, according to both groups of proficiency, the results demonstrated that the advanced learners produce or perceive Korean stops easier than the beginners.