• Sleep Medicine and Psychophysiology
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• v.20 no.2
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• pp.69-74
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• 2013

Introduction: Although it is well known that medical students are not getting an adequate amount of sleep, there have been only a few studies on the sleep patterns of medical students and the related factors. Therefore, the present study aimed to investigate the medical students' sleep patterns and the related factors. Methods: A questionnaire package was administered to the $1^{st}$ to $4^{th}$ year medical students at one medical school. It consisted of questions asking about their lifestyles as well as Pittsburgh sleep quality index (PSQI), Epworth sleepiness scale (ESS), global assessment of recent stress scale (GASS), the center for epidemiologic studies-depression scale (CES-D), and Moudsley obsessive-compulsive inventory (MOCI). A total of 352 students (206 males and 146 females) responded to the survey and the result was analyzed using the independent t-test, the chi-square test, the paired t-test, Pearson's correlation and ANOVA. p-values of less than 0.05 were considered statistically significant in analyses. Results: The weekend bedtime was significantly delayed (0 : 49 on weekday ; 1 : 34 on weekend ; t=-5.23, p<0.001), the weekend rise time was delayed (6 : 58 on weekday ; 9 : 30 on weekend ; t=-24.48, p<0.001) and the total sleep time was increased on weekends (5 : 36 on weekday ; 7 : 39 on weekend ; t=15.94, p<0.001). The PSQI score of all subjects was 6.43{\pm}2.64. PSQI was positively correlated with ESS (r=0.383, p<0.001), GASS (r=0.326, p<0.001), CES-D (r=0.393, p< 0.001), and MOCI (r=0.247, p<0.001), but not with GPA (r=0.072, p=0.228. The more senior students had lower PSQI, GASS, CES-D, and MOCI score (p<0.05). Conclusion: Medical students were experiencing a lack of sleep during weekdays as they have a later bedtime and earlier rise time, and consequently had more hours of sleep on weekends. Overall, the medical students were experiencing poor sleep quality and sleep deprivation. Poor sleep quality is associated with psychological problems (daytime sleepiness, stress, depression, and obsessive tendency).

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2002.05a
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• pp.590-597
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• 2002

LNG고압펌프계통은 천연가스 고압 송출에 있어 가용도가 매우 중요한 계통이다. 본 연구에서는 현재 적용되고 있는 예방(계획)정비주기를 가용성 측면에서 재검토했다. 확률적인 운전대수와 운전 및 보전 형태에 연관된 여러제약이 고려할 때 계통 불가용도를 정량화하기 위하여 시뮬레이션 기법을 적용했다. 중도 절단된 형태의 펌프 수명 데이터를 분석해 욕조형의 고장율 함수를 도출했으며 보수시간 데이터를 분석해 확률분포모수를 구했다. 또한 주요 펌프부대설비에 대해서는 상수형의 고장율과 보전율을 도출했다. 분석된 확률모수를 작성된 시뮬레이션 모형에 입력하고 과거의 운전대수 시나리오를 설정해 실험한 결과와 실제 보수 및 운전 자료를 비교해 모형의 유효성을 보였다. 그리고 차후 예상되는 운전요구대수 시나리오를 기정하고 각 예방정비주기별로 반복 실험하여 계통의 불가용도를 보이고 적합한 예방정비주기를 도출했으며 펌프부품 교체비용의 기대 절감액을 보였다.

• Annual Conference of KIPS
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• 2021.11a
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• pp.148-151
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• 2021

본 논문은 oneM2M을 활용하여 스마트시티의 일환으로 사회적 이슈가 되고 있는 미세먼지(PM10, PM2.5) 측정 플랫폼을 설계하였다. 미세먼지 측정 디바이스를 이동식 차량에 부착하여 미세먼지가 측정이 되고 있지 않은 사각지대까지 범위를 넓혀 측정하였다. 또한 미세먼지뿐만 아니라 일상생활과 연관된 온도, 습도, 대기압, 휘발성 유기화합물(VOC), 일산화탄소(CO), 아황산가스(SO₂), 이산화질소(NO₂), 소음을 센서의 응답 시간에 따라 최소 10초 간격으로 수집하였다. 수집된 정보들은 미세먼지 측정 디바이스 기준으로 반경 1km내 격자모양으로 지형 화면에 실시간으로 표시하고 모니터링함으로서 동작성을 확인하였다.

• Proceedings of the Korea Inteligent Information System Society Conference
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• 2006.06a
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• pp.288-293
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• 2006

최근 반도체 개발 및 제조부문에서는 급속도로 성장한 Mobile 시장과 Digital Consumer Trend 에 주도적으로 대응하고자 빠른 속도의 기술적 변화를 추진하여 왔으며, 이에 따라 현장에서 발생하는 기술적 문제의 유형 또한 점점 복잡 다양해지고 있다. 기존 Commodity 제품의 경우, 세대 전환이 느리게 진행되어, 이에 수반되는 기술적 문제의 난이도와 그 발생 종류가 현재 대비 상대적으로 단순하였다. 그러나 최근 다품종 주문형 제품비중 확대로, 발생되는 문제점들이 Field Application 과 tight 한 연관성을 지니고 있어, 문제의 발생 경로, 원인 파악과 해결 대책 수립에 상당한 초기대응 시간을 필요하며, 관련 부서와의 실시간 협업 및 Cross-Checking을 통하지 않고서는 문제에 대한 최적 Solution 을 결정하기 힘든 현실이 되었다. 이러한 기술 이슈 해결 과정에 기 발생했던 유사 이슈 처리 과정 및 결과 자료가 문제 해결에 크게 기여할 수 있으나, 종래의 지식관리 시스템 체계로는 이러한 실무 형 지식을 획득하기 어려운 부분이 한계점으로 지적되고 있다. 본 논문에서는 이러한 문제점 개선이 가능한 실무형 지식 관리 (AKM: Actual Knowledge Management) 기반의 기술적 이슈 추적 관리 시스템(TITS: Technical Issue Tracking System) 구축 사례를 제시하고자 한다. TITS 는 1) 기술 이슈의 발의 및 전파 기능과 2) 이슈 해결을 위한 Action Item 부여 및 의견 교환 기능 3) 해결된 이슈의 처리 결과 등록 기능 4) 유사 이슈 사례 검색 기능 등의 크게 4 개 모듈오 구성 되어있다. 이 시스템을 통해 반도체 엔지니어들은 기술적 이슈의 발생 시점부터, 원안분석, 대책 협의 ; Action Item 수립 등 문제 해결 과정과 결과 등록 시점까지 Real time Tracking이 가능해 졌으며, 본 시스템을 통해 처리된 모든 기술적 이슈 정보는 Issue Case Database 에 분류 저장되어, 향후 유사 이슈 발생 시, 이를 활용함으로써, 빠른 초기 대응 및 문제 해결에 직접적인 도움을 받을 수 있게 되었다.

• Journal of Chest Surgery
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• v.38 no.1 s.246
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• pp.56-62
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• 2005

Because of high morbidity and mortality, traumatic diaphragm injury remains a diagnostic challenge. In this study, we evaluate that some factors and scores can be used as predictors. Material and Method: From May 1995 to June 2003, 23 patients with traumatic diaphragm injury were enrolled. We examined the clinical features of patients. RTS, TRISS, ISS and APACHE II scores for each patient are calculated for analyzing the relationship of mortality and ICU duration. Result: The study identified 15 men $(65.2{\%})$ and 8women $(34.8{\%})$. There are right sided diaphragmatic injury in 11 patients $(47.8{\%})$, left sided in 11 $(47.8{\%})$, and both sided in 1 ($0.4{\%}$). Plain X-ray, CT, upper GI contrast study and esophagogastroscopy were used as diagnostic tools. Age, hemodynamic status, early diagnosis are not associated with outcome. As prognostic factor, RTS and ISS are associated with mortality and there was negative relationship between RTS and ICU duration (r=0.737, p=0.026). Conclusion: An early diagnosis of traumatic diaphragm injury can frequently be missed in the acute trauma setting. So high index of suspicion and a careful examination are important in multiple trauma patients. An RTS can probably be used effectively as a predictor for the severity and prognosis in patients with traumatic diaphragm injury.

• Clinical and Experimental Pediatrics
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• v.49 no.5
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• pp.482-488
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• 2006

Purpose : To evaluate the factors which contribute to the time of the first stool and the first urine passage. Methods : We retrospectively reviewed a chart of 1,221 infants ${\geq}34$ weeks of gestational age admitted to the normal newborn nursery of Il Sin Christian Hospital, Busan, from November 2004 to April 2005. We compared the time to first stool and urine according to maternal factors(maternal age, parity, mode of delivery, meconium-stained amniotic fluid, and maternal diabetes) and infant factors (gender, Apgar score, gestational age, type of feeding during first 24 hours, age at the first feeding, number of feeds during the first 12 hours and age at discharge). Results : In total, 95.3 percent of our infants had passed their first stool by 24 hours and 99.8 percent of them had a stool by 36 hours. A total of 95.8 percent of our infants had passed urine by 24 hours of age and 98.3 percent of them by 36 hours. Comparing preterm and term infants, the time to first urine is $6.5{\pm}5.8$ hours and $12.1{\pm}6.6$ hours, respectively(P=0.000). The time to first stool is $20.7{\pm}13.5$ hours and $10.0{\pm}6.3$ hours, respectively(P=0.000) Early-fed infants were significantly earlier in time to first urine(P=0.023) and first stool(P=0.012). There was no statistically significant relationship between the number of feeds in 0-12 hours, mode of delivery, Apgar score, parity, gender, type of feeding, maternal diabetes and the time of the first urine and first stool. Conclusion : Gestational age, birth weight and age at first feeding were significantly related to the time of the first urine and first stool passage. When there is delayed passage of the first urine and first stool, we should consider close observation of other associated symptoms and other factors previously mentioned, to avoid extensive evaluation and intervention.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.5
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• pp.334-342
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• 2019

This study is empirically intended to look into the effects of parents' perception of their children's forest experience activities on educational effectiveness. The results were as follows. First, parents' perception of forest experience operation activities had a significant effect on educational effectiveness according to the period of participation in forest experience education. And their perception of the appropriate number of teachers to support forest experience had a significant effect on educational effectiveness. Second, parents' perception - which it is appropriate for the current daycare centers to participate in forest experience every day except a day with a lot of fine dust and a day with bad weather- had a significant effect on educational effectiveness. And their perception of appropriate forest experience places had a significant effect on educational effectiveness. Third, parents' perception of appropriate time in the day for forest experience activities had a significant effect on educational effectiveness. Fourth, parents' perception of their children's forest experience activities had a significant effect on communication. As for the above-stated findings, there was a significant difference in educational effectiveness and communication according to parents' perception of their children's overall forest experience activities. Consequently, there is the differences in their perception of educational effectiveness in the number of teachers in charge due to outdoor activities, the relationship with weather due to fine dust, forest experience places, education time, etc, indicating that these common concerns are related to the safe educational activities of children.

• Journal of the Korea Society of Computer and Information
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• v.10 no.2 s.34
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• pp.133-141
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• 2005

We need to study on simulation method of user's mobility Patterns for the performance analysis of the location management in wireless mobile networks. For this purpose ,this paper presents a user mobility model of wireless mobile networks with regular Patterns Sometimes mobile users randomly move , but they show the movement characteristics that regularly change their locations in some patterns in given time slots. So, we suggest the mobility model that can describe user's time related movement patterns. This model consists of some elements-positions, transitions , transition Probabilities which are variable, and some geographical paths for each transitions. We describe the simulation method for users' mobilities with random movements and regular movements , too. The simulation results by the model show that the suggested model can generate movement scenarios having regular patterns related with location and time.

• Journal of Animal Science and Technology
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• v.46 no.1
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• pp.91-96
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• 2004

It is generally believed that amino acids occurring naturally in mammals are of the L-configuration. D-amino acid(DM) are common in nature as constituents of bacterial cell walls and several antibiotics. Recent reports have demonstrated the presence of small amounts of free DM in milk. The presence of free DM may affect the food quality by decreasing the nutritional value. Our objective was to examine whether the free DM carne from psychrotrophic bacteria. Free DM was produced by treating raw milk with Pseudomonas spp. The samples were extracted with sulphosalicylic acid and derivatized with AccQ-$Tag^{TM}$ reagent when the analysis was carried out by reverse-phase HPLC. We tested correlations of the content of free DM with bacterial growth. Significant amounts of free D-a1anine and D-proline have been found in the raw milk inoculated with Pseudomonas spp. The increase of D-alanine and D-proline appeared to be mainly related to the presence of Pseudomonas fluorescens. These results suggest that free DM may be considered as an indicator of psychrotrophic bacterial milk contamination.

• Journal of Sericultural and Entomological Science
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• v.20 no.2
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• pp.15-19
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• 1978

In order to identify hormone activities which related to the changing of cutaneous tissue and pupal bodies and also to identify the interaction of corpora allata hormone and prothoracic glandular band hormone which act upon the metamorphosis of the insect. The item of treatment is carried out in 5 different times at the interval of about 12 hours after 4 weeks from the first feeding of 4th instar stage, and as far as 5th instar stage in concerned 6 times of item treatments have been carried out, at about 12 hours interval after 72 hours from the molting, Item treatments were, made in the stage of spring, autumn rearing, However, during the period of post mounting stage and pre pupation by picking out of corpora allata in 5 times at the interval of hours the following change of pupal colour is observed; 1) By an early pick out of 4th instar stage, the three molters are found in greater number, However, by a later pick out the four molters are found instead of others. 2) An abnormal colour is found in the three and four molters when comparing with the control molters. 3) The most of control molters have shown the normal colour except a few samples. 4) As shown in the table 1 and 2, the death number of item treatment is greater in the autumn rearing season. 5) The picking out of corpora allata of 5th instar stage, the post mounting stage and pre pupation period is affecting the change of colour. 6) As a final conclusion, the corpora allata hormone is closely related to the changing of pupal colour.