• 해양환경안전학회지
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• 제24권3호
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• pp.339-345
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• 2018

Sunrise and sunset times differ depending on location and date. Previous studies conveniently but monotonously applied day and night times set up. This research defined the daytime and nighttime while considering the time of twilight according to the date and the location of ship collision accidents. Classifying the frequency of ship collision accidents with this standard, we conducted a chi-squared test for the difference between daytime and nighttime. The frequencies of ship collision accidents according to daytime and nighttime was compared by season, month, and time, and all of them showed statistically significant differences. The highest number of daytime ship collisions was 11.6 %, in June, and nighttime collisions peaked at 13.7 %, in December. The most frequent hour for daytime ship collisions was 0700h-0800h, at 10.2 %, and nighttime collisions peaked between 0400h-0500h, at 16.9 %. It is clear that the criteria used in previous studies cited was applied without any theoretical basis and likely only for the convenience of the researchers. It was found that results depend on what criteria are applied to the same research data. This study shows that statistical analyses of marine accidents, traffic volume, and congestion density should be carried out quantitatively while considering daytime and nighttime hours for each particular location and date.

• 한국환경과학회지
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• 제3권3호
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• pp.241-252
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• 1994

Meteorological parameters In the atmospheric boundary layer and the vertical and horizontal dispersion parameters were determined by analyzing the data obtained by the special upper-air observations of one clear day for each season from October 1991 to August 1992. The concentration of the aklospheric pollutants over Taegu was analyzed by using the application of the Gaussian diffusion model. In the diurnal variation of diffusion of atmospheric pollutants, vertical diffusion due to turbulence is active in daytime while horizontal diffusion due to wind is active in nighttime. The mean concentration of pollutants in the side of downwind is higher during the daytime than the nighttime. Thus, the height of the mixed-layer at the nighttime considered as the most important parameter of the mean concentration of pollutants. In the seasonal variation of diffusion of atmospheric pollutants, vertical diffusion due to strong solar radiation is active in summer case day, and horizontal diffusion due to strong wind is active in winter case day. In winter case day, the mean concentration of pollutants in the side of downwind is maximum in the daytime. However, in summer case day, that is maximum in the nighttime.

• 한국안전학회지
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• 제27권2호
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• pp.105-110
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• 2012

This study deals with the accident models of rotary. The objectives is to develop the models by day and nighttime. In pursuing the above, this study gives particular attentions to collecting the data of geometric structure and accidents of 20 rotaries and developing the Poisson and negative binomial regression models using NLOGIT 4.0. The main results are as follows. First, the numbers of accident of nighttime (1.03 per 1,000 entering vehicles) were analyzed to be very higher than those of day (0.47 per 1,000 entering vehicles). Second, 4 Poisson models which were all statistically significant were developed, in which the dependent variable were both the number of accident and EPDO (equivalent property damage only). Finally, the number of entry/exit ($X_1$) and the number of entering lane ($X_5$) in the models of the number of accident, and $X_1$ in the EPDO models were adopted as the common variables. The variables were analyzed to be all positive to the dependent variables.

• 부모자녀건강학회지
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• 제2권
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• pp.83-110
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• 1999

The purpose of this study was to identify the sleep/activity patterns of neonates and to provide a baseline data for the development effective mother-infant relationship. Subjects of this study were 36 newborns aged 1-21 days and stayed in Postpartum Care Center in Taejon during the period of October 28th, 1999 to February 10th, 2000. The data were collected using NCASA developed by Barnard et al. and were analyzed with SPSS 7.5 for window program. The results of this study were as follows: 1. An average day sleep of neonates was 8.0 hours, night sleep was 3.6 hours, and total sleep was 11.6 hours. A longest period of day sleep was 3.8 hours and a longest period of night sleep was 3.4 hours. The regularity of day sleep was 22.1%, night sleep was 23.3%, and total was 22.1%. 2. The frequency of daytime feeding was 6.9, nighttime fee ding was 3.4, resulting in total of 10.3. The regularity of feeding was 37.4%, and the frequency of night awakening was 2.4. 3. Associations among variables related to neonate's sleep/activity records were as follows : - The regularity of total sleep was positively correlated with the frequencies of day sleep(r=.57, P=.00), night sleep (r=.40, P=.01), and total sleep(r=.65, P=.00). - The frequency of total feeding was negatively correlated with the frequencies of day sleep(r=-.29, P=.04), night sleep(r=-.39, P=.02), and total sleep(r=-.42, P=.00), as well as longest day sleep(r=-.50, P=.00). - The regularity of feeding was negatively correlated with the frequency of night sleep(r=-.35, P=.02), longest period of day sleep(r=-.32, P=.04), and longest period of night sleep(r=-.30. P=.04), whereas positively correlated with frequencies of daytime feeding (r=.29, P=.02) and nighttime feeding (r=.32, P=.05). - The frequency of night awakening was negatively correlated with amount of night sleep(r=-.39, P=.02) and frequency of daytime feeding(r=-.42, P=.01) while positively correlated with frequencies of nighttime feeding(r=.68, P=.00) and total feeding(r=.50, P=.00). 4. Although there was no statistical significant difference between sleep pattern and infant's age, following tendency was noted: - As baby gets older, total amount of sleep and longest period of day sleep decreased while longest period of night sleep increased. - As baby gets older, the regularity of day sleep decreased while the regularity of night sleep and total sleep slightly increased. - The frequencies of daytime and total feedings increased while the frequency of nighttime feeding decreased. In conclusion, the author found that the neonates of this study showed less amount of sleep, more night awakening, and more night time feedings than NCAST sample. There was a certain sleep/activity pattern existed: If babies were fed more frequently, daytime or nighttime sleeping hours became shorter, and if babies had longer daytime sleep, frequent nighttime awakenings were noted. This pattern illustrated the significant influence of feeding and sleep periods on each other. Awakening in the night is natural and normal patterns in the newborn period. The result of this study will provide information to parents about what to expect their infants.

• Journal of Korean Society for Atmospheric Environment
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• 제18권E2호
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• pp.57-68
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• 2002

Atmospheric dry deposition fluxes and size segregated concentrations of particulate metal elements were measured at four sites in Kunpo, a small city in the Seoul metropolitan area in Korea. At each site, aerosol samples were collected by dry deposition plates, a cascade impactor, and a coarse panicle rotary impactor during four sampling periods. At all sites, the average fluxes of metals measured during daytime were higher than nighttime fluxes due to higher wind speeds and higher ambient concentrations during daytime. The average fluxes of crustal elements (Al, Ca) were 1∼2 orders of magnitude higher than anthropogenic elements (As, Cd, Cu, Mn, Ni, Pb, and Zn). The daytime fluxes of Al and Ca were between 90 and 12000 $\mu\textrm{g}$ m$\^$-2/ day$\^$-1/, and the nighttime fluxes of Al and Ca were between 20 and 2200 $\mu\textrm{g}$ m$\^$-2/ day$\^$-1/. The daytime fluxes of Pb, a typical anthropogenic element, were between 20 and 160$\mu\textrm{g}$ m$\^$-2/ day$\^$-1/, and the nighttime fluxes of Pb were between ND and 100$\mu\textrm{g}$ m$\^$-2/ day$\^$-1/. Also the ambient metal concentrations during daytime were higher than nighttime. Based on a dust emission estimation study in Kunpo, it was found that dust emissions during daytime are higher than nighttime. The concentrations of crustal elements were higher than anthropogenic elements. The distributions of heavy metals were mainly in small particles (D$\_$p/ 9㎛). The fraction of crustal elements in the large particles (D$\_$p/> 9㎛) were higher than anthropogenic elements.

• 대한지리학회지
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• 제37권3호
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• pp.237-246
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• 2002

본 연구는 최근 30년 (1971-2000) 최한월 (1월) 평균 기온 및 풍속, 일사량 자료를 토대로 산출한 겨울철 주.야간 바람냉각지수의 분포를 바탕으로 남한의 겨울철 생리 기후지역을 구분하였다. 그 결과. 겨울철 주.야간 바람냉각지수는 기온, 풍속, 일사량 등의 기후요소뿐 아니라 해발고도, 해륙풍, 지형, 해류 등의 기후인자의 영향을 받아 남한은 크게 5개의 생리기후지역으로 세분되었다: 주간 서늘-야간 추움 지역, 주간 쌀쌀-야간 추움 지역, 주간 쌀쌀-야간 매우추움 지역, 주.야간 모두 추움 지역, 주간 추움-야간 극도로 추움 지역, 특히, 남해안을 제외한 해안-도서지역은 계절풍 및 해륙풍의 영향으로 주간에는 싸늘함(Keen), 야간에는 매우 추움(Very Cold)의 체감도를 보였다. 또한, 해발고도가 높은 대관령 지역에서는 기온 감률 및 계절풍의 영향으로 주간에는 추움(Cold), 야간에는 극도로 추움(Extremely Cold)의 체감도를 보였다. 본 연구는 다양하게 나타나는 주야간 바람냉각지수의 분포를 바탕으로 남한의 겨울철 생리기후 지역을 구분함으로써 의복 및 건축 등의 단열에 관한 의사결정시 필요한 기초자료를 제공하고자 하였다.

• 대한화학회지
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• 제13권4호
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• pp.249-261
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• 1969

Studies of photochemical reactions of the pure oxygen atmosphere are made using reaction rate constants and atmospheric data available in the latest literature. The daytime and nighttime variations in atomic oxygen and ozone are computed, based on three different conditions: 1) photochemical equilibrium, 2) direct integrations of the rate equations with modifications and approximation to the equations, and 3) by numerical integrations. The departure from the photochemical equilibrium concentrations during day and nighttime are discussed by comparing the results obtaind from the three conditions.

• 한국전문물리치료학회지
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• 제15권4호
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• pp.43-49
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• 2008

The objective of this study was to compare the differences on the activity and power of the wrist flexors and extensors in subjects before the use of a wrist extension splint, after nighttime wearing of the splint, and after daytime wearing of the splint. Ten healthy male and ten healthy female students (mean: $22.4{\pm}1.2$ years old) volunteered to wear custom-made wrist splints either during the night or during the day, The hand force of the wrist flexor and extensor, and grip force were measured by PowerTrack II and Dynatron, respectively. At the same time, the activities of the wrist flexor and extensor were recorded by' surface electromyography. The maximal hand force and motor unit recruitment of the flexor carpi ulnatis (FCU) increased significantly (p<.05) when tile subjects wore the wrist splints during the daytime, but the maximal hand power of the FCU decreased with nighttime use of the splints. The maximal hand power and motor unit recruitment of the extensor carpi radialis (ECR) and the ECR/FCU ratio decreased both during nighttime and daytime use. The decrement of the ECR/FCU ratio was significant (p<.05). Wearing a wrist extension splint during nighttime led to the maintenance of a lengthened position of the wrist flexor, resulting in the wrist flexor becoming weak. Wearing a wrist extension splint during the day induced the wrist flexors to be greater. In healthy people, the imbalance between the wrist flexors and extensors may be caused by the use of a wrist extension splint. This study indicates that therapists have to consider whether a splint will be effective, as well as the wearing time, when prescribing splints to people with problems of the musculoskeletal system.

• 한국도로학회논문집
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• 제17권4호
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• pp.107-115
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• 2015

PURPOSES: This study analyzes the characteristics of traffic flow on freeway sections under daytime and nighttime conditions to improve traffic safety, and suggests a method to estimate an accurate freeway capacity value that reflects these characteristics. METHODS : The trends and differences in capacity were investigated using comprehensive field data collected under both daytime and nighttime conditions on freeway sections with designated speeds of 80, 100, and 120 kph. RESULTS : The capacity values under nighttime driving conditions were reduced by 3.3%, 6.9%, and 8.8% at 80, 100, and 120 kph, respectively. Several nighttime adjustment factors were deduced for each designated speed category from the analysis results. CONCLUSIONS : It is expected that more accurate capacity values can be estimated for freeway sections under nighttime conditions by applying the resulting adjustment factors. In addition, traffic safety will be improved through the increased efficiency of traffic management on these freeway sections.

• 대한토목학회논문집
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• 제28권2D호
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• pp.181-189
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• 2008

본 연구는 주간과 야간의 교통사고 특성과 사고모형을 비교 분석하는데 그 목적이 있다. 이를 위해 본 연구에서는 청주시 4지 신호교차로를 중심으로 주 야간 교통사고의 차이를 검증하고, 주야간별 다중선형, 다중비선형 과 포아송 및 음이항회귀모형을 개발하는데 중점을 두고 있다. 분석된 주요 연구결과는 다음과 같다. 첫째, 사고특성 분석을 통해 주간과 야간 사고의 차이점이 파악되었다. 둘째, 통계적으로 설명력이 높은 주 야간 총 12개의 사고모형이 개발되었다. 마지막으로 공통변수와 특정변수를 활용하여 주야간 사고모형의 차이가 비교 분석되었다.