• Sleep Medicine and Psychophysiology
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• v.3 no.1
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• pp.47-55
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• 1996

Narcolepsy is characterized by sleep attack with excessive daytime sleepiness(EDS), cataplexy, sleep paralysis, and hypnagogic hallucination. Paradoxically, narcoleptics tend to complain of frequent arousals and shallow sleep during the night time despite their excessive sleepiness. However, nocturnal sleep fragmentation in narcoleptics is relatively ignored in treatment strategies, compared with sleep attack/EDS and cataplexy. In our paper, we attempted to investigate further on the poor nocturnal sleep in narcoleptics and to discuss possible treatment interventions. Out of consecutively seen patients at Seoul National University Sleep Disorders Clinic and Division of Sleep Studies, we recruited 57 patients, clinically assessed as having sleep attack and/or EDS. Nocturnal polysomnography and multiple sleep latency test(MSLT) were done in each of the subjects. We selected 19 subjects finally diagnosed as narcolepsy(mean age $26.0{\pm}18.3$ years, 16 men and 3 women) for this study, depending on the nocturnal polysomnographic and MSLT findings as well as clinical history and symptomatology. Any subject co-morbid with other hypersomnic sleep disorders such as sleep apnea or periodic limb movements during sleep was excluded. Sleep staging was done using Rechtschaffen and Kales criteria. Sleep parameters were calculated using PSDENT program(Stanford Sleep Clinic, version 1.2) and were compared with the age-matched normal values provided in the program. In narcoleptics, compared with the normal controls, total wake time was found to be significantly increased with significantly decreased sleep efficiency(p<.01, p<.05, respectively), despite no difference of sleep period time and total sleep time between the two groups. Stage 2 sleep%(p<.05), slow wave sleep%(p<.05), and REM sleep%(p<.01) were found to be significantly decreased in narcoleptics compared with normal controls, accompanied by the significant increase of stage 1 sleep%(p<.01). Age showed negative correlation with slow wave sleep%(p<.05). The findings in the present study indicate significant fragmentation of nocturnal sleep in narcoleptics. Reduction of REM sleep% and the total number of REM sleep periods suggests the disturbance of nocturnal REM sleep distribution in narcoleptics. No significant correlations between nocturnal polysomnographic and MSLT variables in narcoleptics suggest that nocturnal sleep disturbance in narcoleptics may be dealt with, in itself, in diagnosing and managing narcolepsy. With the objective demonstration of qualitative and quantitative characteristics of nocturnal and daytime sleep in narcoleptics, we suggest that more attention be paid to the nocturnal sleep fragmentation in narcoleptics and that appropriate treatment interventions such as active drug therapy and/or circadian rhythm-oriented sleep hygiene education be applied as needed.

• Journal of Digital Convergence
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• v.17 no.10
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• pp.453-459
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• 2019

This study was conducted to investigate the effects of video - based movement therapy program on emotional variables (anxiety, depression, panic disorder) and EEG on panic disorder patients. The following conclusions were obtained. The results of the 12 - week video - based behavior therapy program showed that there were statistically significant differences (p <.05) in the anxiety scale of the exercise group. There were statistically significant differences (p <.05) between the left brain L-Beta region of the exercise group and the left brain H-Beta and the right brain L-Beta regions of the control group and no significant difference was found between the groups. The results of this study suggest that the performance of the video-based behavioral therapy program for panic disorder patients did not affect the emotional variables and EEG changes. However, in the case of emotional variables, It is considered that the longer the program execution period, the more result will be obtained. In addition, it is expected that more positive study results can be expected if the program is run after having had enough familiarity and adaptation time of the operation treatment program omitted in this study.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.25 no.5
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• pp.335-347
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• 2013

In February 2008, high storm waves due to a developed atmospheric low pressure system propagating from the west off Hokkaido, Japan, to the south and southwest throughout the East Sea (ES) caused extensive damages along the central coast of Japan and along the east coast of Korea. This study consists of two parts. In the first part, we estimate extreme storm wave characteristics in the Toyama Bay where heavy coastal damages occurred, using a non-hydrostatic meteorological model and a spectral wave model by considering the extreme conditions for two factors for wind wave growth, such as wind intensity and duration. The estimated extreme significant wave height and corresponding wave period were 6.78 m and 18.28 sec, respectively, at the Fushiki Toyama. In the second part, we perform numerical experiments on wave-structure interaction in the Fushiki Port, Toyama Bay, where the long North-Breakwater was heavily damaged by the storm waves in February 2008. The experiments are conducted using a non-linear shallow-water equation model with adaptive mesh refinement (AMR) and wet-dry scheme. The estimated extreme storm waves of 6.78 m and 18.28 sec are used for incident wave profile. The results show that the Fushiki Port would be overtopped and flooded by extreme storm waves if the North-Breakwater does not function properly after being damaged. Also the storm waves would overtop seawalls and sidewalls of the Manyou Pier behind the North-Breakwater. The results also depict that refined meshes by AMR method with wet-dry scheme applied capture the coastline and coastal structure well while keeping the computational load efficiently.

• Journal of the korean academy of Pediatric Dentistry
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• v.7 no.1
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• pp.75-83
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• 1980

Rickets is not the deposite of minerals in the skeletal tissue and the retardation of skeletal growth in growing in growing animals. This study was undertaken to investigate the histologic effects of experimental rickets on the dental structure of the albino rats, and to show the relationship between the histological effects and the pulpal disease which induced premature loss of the primary teeth. This study was based on material obtained from 40 white rats that were placed on a rachitogenic diet for a period 1 to 56 days after weaning (at 24 days). In addition, a study was made of 25 litter mates, 24 to 80 days, that were fed a normal diet. The following results were obtained: 1. Enamel formation and calcification showed no significant changes and no hypoplasia. 2. Dentin formation and calcification was retarded and disturbed. In the experimental group, predentin/calcified dentin was remarkablly increased. 3. Newly formed dentin showed interglobular texture (less homogenous calcification) and the predentin was significantly wider and thicker, and there was an irregular wave in the basal portion of the rat's incisors. 4. In cementum, Matrix formed at almost a normal rate but calcification was defective. So cementoid tissue was increasesd. 5. The formation of the alveolar bone was at almost a normal rate but calcification was retarded. The trabecular bone was filled with osteoid tissue and thicker than in normal groups.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.3
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• pp.171-180
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• 2016

Earthquake event keeps increasing every year, and the recent cases of earthquake hazards invoke the necessity of seismic study in Korea, as geotechnical earthquake hazards, such as strong ground motion, liquefaction and landslides, are a significant threat to structures in industrial hub areas including coastal facilities. In this study, systemized framework of integrated assessment of earthquake-induced geotechnical hazard was established using advanced geospatial database. And a visible simulation of the framework was specifically conducted at two coastal facility areas in Incheon. First, the geospatial-grid information in the 3D domain were constructed with geostatistical interpolation method composed of multiple geospatial coverage mapping and 3D integration of geo-layer construction considering spatial outliers and geotechnical uncertainty. Second, the behavior of site-specific seismic responses were assessed by incorporating the depth to bedrock, mean shear wave velocity of the upper 30 m, and characteristic site period based on the geospatial-grid. Third, the normalized correlations between rock-outcrop accelerations and the maximum accelerations of each grid were determined considering the site-specific seismic response characteristics. Fourth, the potential damage due to liquefaction was estimated by combining the geospatial-grid and accelerations correlation grid based on the simplified liquefaction potential index evaluation method.

• Journal of Ocean Engineering and Technology
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• v.7 no.2
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• pp.114-120
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• 1993

Responses of marine vehicles and ocean structures in a seaway can be predicted by applying the probabilistic approach. When we consider a linear system, the responses in a random seaway can be evaluated through spectral analysis in the frequency domain. But when we treat nonlinear system in irregular waves, it is necessary to get time history of waves. In the previous study we introduced one-directional waves (long crested waves)as wave environment and carried out calculations and experiments in the waves. But the real sea in which marine vehicles and structures are operated has multi-directional waves (short crested waves). It is important to get a simulated random sea and analyse dynamic problems in the sea. We need entire sample function or probabillty density function to infer statistical value of random process. However if the process are ergodic process, we can get statistical values by analysis of one sample function. In this paper, we developed the simulation technique of multi-directional waves and proved that the time history given by this method keep ergodic characteristics by the statistical analysis.

• Asia Pacific Journal of Corpus Research
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• v.1 no.1
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• pp.1-30
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• 2020

The present study examines language used to talk about the global coronavirus pandemic during a three-month period of movement control order in Malaysia. More specifically, a corpus of online letters to the editor of a local popular national newspaper was collected during the time in which the official quarantine instruction was initiated, resulting in a total of 303 online letters written by Malaysians that were analyzed through use of corpus linguistics techniques. For this purpose, the latest version of #LancsBox 5.0 (Brezina et al., 2020) is used to analyze patterns of language surrounding the portrayal of Covid-19 and further visualizing them by use of collocation networks. Findings present 25 statistically significant collocates that share an interesting relationship in revealing what the letters are about and thus, reflecting how Malaysians perceive and receive news about the pandemic during this time. Recurring topics and expressions include describing the virus in terms of metaphorical use of language (Covid-19 does not discriminate), preparing for an economic fallout (Prihatin Economic Stimulus Package), and preference to associate Covid-19 as a pandemic (impacts of the Covid19 pandemic) rather than an outbreak (first/second/third wave of the outbreak). Implications of the study resonates with findings from Azizan et al. (2020) where constructions of positive discourse among Malaysian writers may reflect the culture and society that make up the nation.

• Journal of Chest Surgery
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• v.22 no.1
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• pp.67-73
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• 1989

Forty two patients with chronic constrictive pericarditis, who were admitted to the Yonsei University College of medicine over a period of 18 years from January, 1970 to August, 1988, were analyzed retrospectively. Mean age of the patient was 33.5 year ranging from 6.8 to 60 years old. Male to female ratio was 1.3 to 1. Twenty-one cases [50%] were tuberculous origin [based on either associated pulmonary tuberculosis and/or caseous necrosis in thickened pericardial specimen] and 17 cases [40.5%] were idiopathic [non specific chronic inflammatory change was considered to be idiopathic]. Dyspnea on exertion was evident in 30 cases [71.4%] and abdominal distention in 21 cases [50%]. On physical examination, hepatomegaly [83.3%], neck vein distention [54.8%], distant heart sound [47.6%] and ascites were found. Thirty-nine patients showed low voltage of QRS and/or T wave flattening or inversion on EKG. Thirty-one cases had undergone cardiac catheterization which showed data compatible with chronic constrictive pericarditis. Midsternostomy group [n=15] had shown the most remarkable CVP decline [12.20 mmHg] as compared with bilateral submammary incision group [n=25, 8.96 mmHg] and left thoracotomy group [n=2, 7.75 mmHg] but difference was not significant statistically There was four early death among 42 patients [9.5%] including 3 cases of left ventricular failure and one cardiac tamponade. Main postoperative complications were wound infection [6 cases] and arrhythmia [3 cases]. Follow-up of 24 patients [mean; 55.3 months, ranging from 2 months to 155 months] revealed good functional status.

• Clinical and Experimental Pediatrics
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• v.50 no.8
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• pp.711-717
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• 2007

Sleep is a vital, highly organized process regulated by complex systems of neuronal networks and neurotransmitters. Normal sleep comprises non-rapid eye movement (NREM) and REM periods that alternate through the night. Sleep usually begins in NREM and progresses through deeper NREM stages (2, 3, and 4 stages), but newborns enter REM sleep (active sleep) first before NREM (quiet sleep). A period of NREM and REM sleep cycle is approximately 90 minutes, but newborn have a shorter sleep cycle (50 minutes). As children mature, sleep changes as an adult pattern: shorter sleep duration, longer sleep cycles and less daytime sleep. REM sleep is approximately 50% of total sleep in newborn and dramatically decreases over the first 2 years into adulthood (20% to 25%). An initial predominant of slow wave sleep (stage 3 and 4) that peaks in early childhood, drops off abruptly after adolescence by 40% from preteen years, and then declines over the life span. The hypothalamus is recognized as a key area of brain involved in regulation of sleep and wakefulness. The basic function of sleep largely remains elusive, but it is clear that sleep plays an important role in the regulation of CNS and body physiologic processes. Understanding of the architecture of sleep and basic mechanisms that regulate sleep and wake cycle are essential to evaluate normal or abnormal development of sleep pattern changes with age. Reduction or disruption of sleep can have a significant impact on daytime functioning and development, including learning, growth, behavior, and emotional regulation.

• Journal of Ocean Engineering and Technology
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• v.20 no.2 s.69
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• pp.46-51
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• 2006

Moonpool characteristics of a cleaning skip related with the performance of a skip are experimentally investigated. Resistance performances of the ship and flow patterns in the moonpool are observed, in order to determine the effect of different shaped moonpool. The ways to reduce ship pithing motion caused by force in the moonpool are examined. Experimental results, using a scale model of cleaning ship with moonpool, show that the step arranged in tier under water leads to significant improvements in performance, such us resistance and ship pithing motion. Depending upon the shape of step in the moonpool, the results indicate that the increment of resistance performance may be up to 35%, especially in the case of no step or high step.