• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.17 no.2
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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.

• Phonetics and Speech Sciences
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• v.14 no.2
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• pp.77-86
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• 2022

This study aimed to investigate the voice onset time (VOT) of plosives in the VCV syllables by the place of articulation and phonation type spoken by children with bilateral cochlear implants (CIs) in comparison with children with typical hearing (TH). In all, 15 children with bilateral CIs and 15 children with TH participated in this study, aged between 5 to 10 years. All children produced 9 VCV syllables and their VOT were analyzed by the Praat software. There was no significant difference in mean VOT between children with bilateral CIs and children with TH. However, there was a significant difference in mean VOT by the place of articulation, such that the VOT for velars were longer than those for bilabials and alveolars. Additionally, there was a significant difference in mean VOT by the phonation type, such that the VOT of aspirated consonants were longer than those of lenis and fortis consonants. The results of this study suggest that children with bilateral CIs can distinguish the acoustic properties of plosive consonants and control the speech timing between the structures of the larynx and the oral cavity at a similar level as children with TH.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.3
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• pp.279-285
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• 2011

We perform a numerical study to determine the time of onset of natural convection in a transient hot wire (THW) device for measuring the thermal conductivity of nanofluids. The samples used in this simulation are water-based $Al_2O_3$ nanofluids with volume fractions of 1%, 4%, and 10%, and the properties are calculated by theoretical models and experimental correlations. The THW apparatus using coated wire is modeled by the control-volume-based finite difference method, and the start of natural convection is determined by observing the temperature rise of the wire under a gravity field. The onset time is 11.5 s for water and 41.6 s for water-based $Al_2O_3$ nanofluids predicted by Maxwell thermal conductivity model with a 10% volume fraction. We confirm that the onset time of natural convection of nanofluids in the cylinder increases with the nanoparticle volume fraction. We suggest a correlation for predicting the onset time on the basis of the numerical results. Finally, it is shown that the measurement error due to natural convection is negligible if the measurement using the transient hot wire method is completed before the onset of natural convection in the base fluid.

• Journal of the Korean earth science society
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• v.39 no.6
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• pp.593-599
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• 2018

The onset times of P- and S-waves are important information to have reliable earthquake locations, 1D or 3D subsurface velocity structures, and other related studies in seismology. As the number of seismic stations increases significantly in recent years, it becomes a formidable task for network operators to pick phase arrivals manually. This study used a simple method to estimate additional P- and S-wave arrival times for local earthquakes when a priori information (event location and time) is available using the Akaike Information Criterion (AIC). We applied the AIC program to the earthquake data recorded at the seismic station located in Gyeongsan (DAG2). The comparisons of automatically estimated phase arrival times with manually picked onset times showed that 95.1% and 93.7% of P-wave and S-wave arrival time estimations, respectively, are less than 0.1 second difference. The higher percentage of agreement presented the method which can be successfully applied to large data sets recorded by high-density seismic arrays.

• Journal of Chest Surgery
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• v.56 no.3
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• pp.186-193
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• 2023

Background: Complete surgical excision is the only curative treatment for primary cardiac tumors. For wide excision, interatrial septal reconstruction (ISR) is commonly performed. We hypothesized that ISR may increase the risk of postoperative atrial tachyarrhythmia (AT) after surgical resection of cardiac myxoma. Methods: After excluding patients with a history of cardiac surgery and concomitant procedures unrelated to tumor resection and those with AT or permanent pacemakers, we finally enrolled 272 adult patients who underwent benign cardiac tumor surgery from 1995 to 2021 at our institution. They were divided into the ISR (n=184) and non-ISR (n=88) groups. The primary outcome was postoperative new-onset AT. Results: The study cohort predominantly consisted of women (66.2%), with a mean age of 57.2±13.6 years. The incidence of postoperative new-onset AT was 15.4%. No 30-day mortality or recurrence was observed. The cardiopulmonary bypass time and aortic cross-clamping time were significantly longer in the ISR group than in the non-ISR group (p<0.001). The median duration of hospital stay of all patients was 6.0 days (interquartile range, 5.0-7.0 days), and no significant difference was observed between the 2 groups (p=0.329). ISR was not an independent predictor of new-onset AT (p=0.248). Male sex and hypertension were found to be independent predictors of new-onset AT. Conclusion: ISR was not a significant predictor of postoperative new-onset AT. ISR might be a feasible and safe procedure for surgical resection of cardiac myxoma and should be considered if needed.

• Korean Journal of English Language and Linguistics
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• v.3 no.3
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• pp.427-452
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• 2003

Korean is famous for having all voiceless stop sounds. Korean does have voiced stops but they are considered to exist only as the allophones of word initial /p, t, k/. My experiment shows the English word initial stop sounds [b, d, g] and the Korean lax stop series /p, t, k/ in word initial position are similar in the range of voice onset time. If English word initial[b, d, g] sounds are posited as voiced, then Korean word initial /p, t, k/ should be classified as voiced also. Phonetically English /b, d, g/ phonemes and Korean /p, t, k/ phonemes are very similar except the word initial [p, t, k] are devoiced slightly more, but not significant enough to be classified as voiceless than English word initial [b, d, g]. If we posit /b, d, g/ as Korean phonemes, it explains why Korean /p, t, k/ series has the allophones [b, d, g] instead of fortis stops /p', t', k'/ in Korean even though /p', t', k'/ has less positive VOT value than /p, t, k/. If we posit /b, d, g/ as Korean phonemes, then it does not cause spelling or pronunciation confusion either when Koreans learn English or English speakers learn Korean.

• Korean Journal of Veterinary Research
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• v.9 no.1
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• pp.11-22
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• 1969

Experimental studies were performed to observe the difference in tolerance of small animals to oxygen poisoning, and also to examine the effects of certain drug for it. The three experimental groups consisted of mature rat group, immature rat group and mouse group. The animals were exposed to 5 atm. of 100% oxygen using hyperbaric chamber, and they were observed for oxygen poisoning by pulmonary and central nervous system manifestation. The tolerance to oxygen poisoning was represented by half fatality time in each experimental group. The drug applied was ammonium chloride $NH_4Cl$ and it was administered intraperitoneally in various dosages for particular attribution of its prophylactic effect. The following conclusions were made; 1. The immature rat group showed the higher degree of tolerance to oxygen poisoning, as evidenced by a more prolonged half fatality time in the group. No significant difference in the half fatality time between the mature rat and the mouse group was observed. 2. The fact that the immature group showed the higher degree of tolerance as compared with the mature rat group represented by delayed onset of convulsion. 3. There was a remarkable difference in the Lung Weight/Body Weight ratio between the experimental and control group. 4. The animals with a shorter half fatality time uniformally displayed an earlier onset of convulsive seizure as the sign of oxygen poisoning and a significant elevated Lung Weight/Body Weight ratio. 5. Ammonium chloride at the dosage of 450mg per kg body weight had the most pronounced prophylactic effect on oxygen poisoning.

• The Journal of Internal Korean Medicine
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• v.21 no.2
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• pp.203-212
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• 2000

Objective : We studied only patients at the acute stage but existing studies on stroke didn't almost classify the stage. We examined 243 patients admitted to the Woo Suk university oriental medical hospital from January 1998 to December 1999 for 2 years. Methods : We analyzed patients into sex, Sasang constitution, the incidence and lesion according to the stroke types, post and family history, onset time, period to admission and physical treatment from onset, and symptom, blood pressure, cholesterol level and herb medicine at entry. Results : Our study was similar to existing studies in the distribution of sex, age and the lesion of stroke, post and family history, and symptoms at entry. But it differed in the constitution, incidence of cerebral infarction and intracranial hemorrhage, attack time, period to admission and physical treatment from onset day, and the symptoms, blood pressure, cholesterol level and herb medication. In comparison between infarction and hemorrhage patients, there was some difference in the distribution of onset time, but wasn't in the cholesterol level. Conclusions : Our study on the acute stage of stroke was similar to existing studies in the general characteristics. But it showed some differences in the herb medicine at entry. In particular, there were much differences in the blood pressure at entry and the incidence of infarction and hemorrhage. We hoped that stroke patients would be synthetically studied in western and oriental medicine.

• The Korean Journal of Pain
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• v.29 no.1
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• pp.29-33
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• 2016

Background: The purpose of this study was to evaluate the effect of dexamethasone or dexmedetomidine added to ropivacaine on the onset and duration of ultrasound-guided axillary brachial plexus blocks (BPB). Methods: Fifty-one ASA physical status I-II patients with elective forearm and hand surgery under axillary brachial plexus blocks were randomly allocated to receive 20 ml of 0.5% ropivacaine with 2 ml of isotonic saline (C group, n = 17), 20 ml of 0.5% ropivacaine with 2 ml (10 mg) of dexamethasone (D group, n = 17) or 20 ml of 0.5% ropivacaine with 2 ml ($100{\mu}g$) of dexmedetomidine (DM group, n = 17). A nerve stimulation technique with ultrasound was used in all patients. The onset time and duration of sensory blocks were assessed. Results: The duration of the sensory block was extended in group D and group DX compared with group C (P < 0.05), but there was no significant difference between group D and group DX. However, there were no significant differences in onset time in all three groups. Conclusions: Dexamethasone 10 mg and dexmedetomidine $100{\mu}g$ were equally effective in extending the duration of ropivacaine in ultrasound-guided axillary BPB with nerve stimulation. However, neither drug has significantly effects the onset time.

• Physical Therapy Korea
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• v.29 no.3
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• pp.215-224
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• 2022

Background: The presence of the lumbopelvic-hip neuromuscular chain is essential for dynamic spinal stabilization; its therapeutic effects on dynamic movements of the distal extremity segment and underpinning motor mechanism remain unknown and warrant further study on participants with low back pain (LBP). Objects: We aim to compare the effects of the broken chain exercise (BCE) and connected chain exercise (CCE) on electromyography (EMG) amplitude and onset time in participants with and without LBP. Methods: Randomized controlled clinical trial. A convenience sample of 40 nonathletic participants (mean age: 24.78 ± 1.70) with and without LBP participated in this study. All participants underwent CCE for 30 minutes, 30-minute daily. We measured EMG amplitude and onset times on bilateral erector spinae (ES), gluteus maximus (GM), hamstring (HAM), transverse abdominis (TrA), internal oblique (IO), and external oblique (EO) during the prone hip extension (PHE) test before and after the BCE and CCE. We used multivariate analysis of variance (MANOVA) to analyze the amplitude and onset time difference between exercises (BCE and CCE) and Pearson's correlations to determine any synergistic relationship among the HAM, GM, bilateral TrA/IO, and ES muscles. The statistical analyses were used at p < 0.05. Results: MANOVA showed that CCE was more decreased on EMG amplitude in HAM and bilateral ES, while increased GM and contralateral TrA/IO than BCE (p < 0.05). MANOVA EMG onset time data analyses revealed that the main effect of the conditions was significant for all HAM, GM, and bilateral ES muscles, whereas the main effect for the group was significant only for GM and contralateral ES in healthy and LBP groups. Pearson's correlation coefficient was computed to assess the relationship between BCE and CCE on dependent variables. In most of the muscles, there was a strong, positive correlation between the two variables, and there was a significant relationship (p < 0.001). Conclusion: CCE produced more effective and coordinated core stabilization and motor control mechanism in the lumbopelvic-hip muscles in participants with and without LBP during PHE than BCE.