• Title/Summary/Keyword: Day and night

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Comparison of Ego-States, Stressors, and Stress Coping Types : Between University Students Day and Night Time (대학생의 학업형태 및 개인특성에 따른 스트레스 발생요인 및 대처방식 비교)

  • Jo, Eun-Hyeon;Lee, Dong-Hyung
    • Journal of Korean Society of Industrial and Systems Engineering
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    • v.39 no.4
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    • pp.117-124
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    • 2016
  • Stress is resistance to stimuli to destroy a balance of mind and body in order to maintain an original steady state : A type of response and avoidance. Mild stress, which happens in tension, has a positive effect to improve concentration, but most of stress is likely to be a main factor to damage health. This is because it causes physical ailments and psychological diseases (e.g., depression, anger, frustration, loneliness, and anxiety). The purpose of this study is to analyze the difference between two groups, daytime and night university students, on ego-state, stressors, and stress coping types to improve their academic achievement by reducing their stress. There were 266 university students, who participated in a survey from November 30, 2015 until September 30, 2016. The study employed three measuring instruments : Ego-gram, stressor scale, and stress coping type scale. All the collected data were analyzed through regression analysis and t-test. The results of the regression analysis showed no significant differences in ego-state, stressors, and stress coping types between two groups. However, the results of t-test showed significant difference between the two groups : In terms of ego-state, a CP (Critical Parent) average of the night university students was significantly higher than the daytime university students'. Also, there is a significant difference in employment, future issues, and economic issues : the daytime university students considered employment and future issues more serious, while the night university students had more mental burdens of economic issues. When it comes to coping stress types, there was no significant difference between the two groups.

The Changes of Traveller's Sleep-Wake Cycles by Jet Lag (비행시차(jet lag)에 의한 여행객의 수면-각성 주기의 변화)

  • Lee, Seung-Hwan;Kim, Leen;Sub, Kwang-Yoon
    • Sleep Medicine and Psychophysiology
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    • v.2 no.2
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    • pp.146-155
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    • 1995
  • Jet lag can be defined as the cumulative physiological and psychological effects of rapid air travel across multiple time zone. The consequences of jet lag include fatigue, general malaise, sleep disturbances, and reductions of cognitive and psychomotor performance, all of which have been documented in experimental biological and air crew personnel studies. Thus authors tried to study the jet lag of natural travellers by modified self reporting sleep log. Total 61 healthy travellers was studied for 3 days before and 7 days after jet-flights across seven to ten time zone. The eastbound travelling group was 38 persons, aged 19 -70 and westbound travelling group was 23 persons, aged 13 - 69. Sleep onset time, wake-up time, sleep latency, awakening frequency on night sleep, awakening duration on night sleep, sleepiness at wake-up and nap length were evaluated. Our results suggested that the 7 to 10 time zone shift gave significant influence to traveller's sleep-wake cycles. The date which subjective physical condition was recovered on was $5.16{\pm}1.50$ day after arrivals for eastbound, while for westbound, $4.91{\pm}1.62$ day. In eastbound travelling, sleep onset time became later than baselines and could not recover until 7th day. But in westbound, it became earlier than baseline and could recover until 6th day. The mean score of 24-hour sleepiness was greater in eastboumd than westbound. Therefore the eastbound travelling caused more sleep-wake cycle disturbance and daytime dysfunction than westbound travelling. In other parameters, there was no definite difference between east and westbound. From our results, it was suggested that the symptom severity of jet lag was dependent on the travelling direction. To demonstrate more definite evidence, large sized data collections and comparision by age difference were needed.

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Statistical Analysis of Ship Collision Accidents by Day and Night Times

  • Yoo, Sang-Lok;Jung, Cho-Young
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.3
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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.

A Study on the Aerobic Digestion Treatment of Night soil (분뇨의 호기성 소화처리에 관한 고찰)

  • 육찬남
    • Journal of environmental and Sanitary engineering
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    • v.11 no.1
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    • pp.77-82
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    • 1996
  • Environmental issues are getting imrx>rtant and the polluted environment is now c considered as one of the serious social problems which we have to face. As a result, most people hate an night soil-treating establishment to be built near their village. This paper is intended to reveal the present situation of Sanitary Environment Bureau in Iksan City and its treatment of night soil. The conclusions are as follows 1. The mean quantity of treated night soil per day was approximately 126kl In 1995, and the treated quantity per month was largest in the months from May to August, but smallest in January and February. The quantity of the largest month doubled the one of the smallest, and it is considered to be because the microorganisms are more active in the warm season than in the cold season, being a a ble to process more night soil. 2. The after-treatment sewage water is regarded as being in an optimalcondition because the examination of the water discharged from the establishment revealed the result of BOD 16.67mg/l and SS 14.78mg/l in 1995. 3. The expense for treating human waste was ₩19,582 in Iksan Sanitary Environment Bureau and it was considerably lower than the average expense through the nation, i.e. ₩22,000-25,000. But the cost should be expanded for keeping outworn equipments from the old age. 4. It is desirable for the Bureau to open the establishment so that any adult or student can come into it and watch all the treating processes. It will help the citizens understand the need for the establishment in spite of its nasty and ugly impression. Other cities or countries have to follow this model and try to provide their citizens with a cleaner environment by investing more fund technology for it.

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The Fractionation Characteristics of Organic Matter in Pollution Sources and River (오염물질 배출원과 하천에서의 유기탄소 분포 특성)

  • Kim, Ho-Sub;Kim, Sang-Yong;Park, Jihyung;Han, Mideok
    • Journal of Korean Society on Water Environment
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    • v.33 no.5
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    • pp.580-586
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    • 2017
  • The fractionation characteristics of organic matter were investigated in inflow and effluent of each other pollution sources and river. While the DOC/TOC ratio in the influent of public sewage treatment plant and livestock disposal facilities was above 0.58, the POC/TOC ratio of human livestock Night soil treatment plant and stormwater runoff was more than 0.7. The TOC removal efficiency of public sewage treatment plant and human livestock Night soil treatment plant were 88.5 % and 99.6 %, respectively. Although the concentration distribution of organic matter pollution most of total organic carbon (TOC) in effluent of pollution sources accounted for dissolved organic carbon (DOC) type (DOC/TOC ratio >0.89) and Refractory-DOC (RDOC)/TOC ratio was higher (>0.65). The fractionation characteristics of organic matter in river were similar with that of sewage treatment plant and TOC concentration showed the positive correlation with DOC ($r^2=0.93$) and RDOC ($r^2=0.89$) concentration. The decay rate of Labile DOC (LDOC) (avg. $0.128day^{-1}$) was higher than labile particulate organic carbon (LPOC) ($0.082day^{-1}$), while that of DOC ($0.008day^{-1}$) was lower than POC ($0.039day^{-1}$) (paired t-test, p < 0.001, n = 5). These study results suggested that it should consider important both TOC and DOC as the target indicator to control refractory organic matter in pollution sources.

The Impacts of Built Environmental Features on the Land Surface Temperatures for the Heat Wave Seasons in Gwangju, South Korea (도시화에 따른 건조환경이 하절기 광주시 외부공간의 열환경에 미치는 영향에 대한 연구)

  • Hong, Sung-Woon;Yang, Dongwoo;Oh, Byoung-Chull
    • Journal of the Korean Solar Energy Society
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    • v.39 no.6
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    • pp.67-82
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    • 2019
  • This study aims to examine the impacts of built environmental features on the nocturnal and diurnal temperatures during the heat wave season in Gwangju, Korea. Built environmental measures are summarized at micro-scale level, such as 50 meters and 100 meters from temperature monitoring spots. Regressing the built environment on nocturnal and diurnal temperatures, we estimate how the artificial constructs contribute to temperature either day and night times. We found that impervious surface ratio is positively and negatively associated with nocturnal and diurnal temperatures, respectively. Buildings and structures tend to construct high thermal mass and absorb heat during day time and emit it for the night time. This property contributes to the nocturnal temperature model. On the other hand, urban areas with more vertical structure tend to block sun radiation more than rural, and it is more likely to find the negative relationship between impervious surface ratio and the diurnal temperatures.

Circadian Rhythms of Melatonin, Thyroid-Stimulating Hormone and Body Temperature: Relationships among those Rhythms and Effect of Sleep-Wake Cycle

  • Kim, Mi-Seung;Lee, Hyun J.;Im, Wook-Bin
    • Animal cells and systems
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    • v.6 no.3
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    • pp.239-245
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    • 2002
  • Plasma melatonin, thyroid-stimulating hormone (TSH) and body temperature were measured simultaneously and continuously before and after the sleep-wake cycle was shifted in 4 healthy males and changes in the circadian rhythm itself and in the phase relationship among these circadian rhythms were determined. Normal sleep-wake cycle (sleep hours: 2300-0700) was delayed by 10 h (sleep hours: 0900-1700) during the experiment. Even after this shift the typical melatonin rhythm was maintained: low during daytime and high during night. The melatonin rhythm was gradually delayed day by day. The TSH rhythm was also maintained fundamentally during 3 consecutive days of altered sleep-wake cycle. The phase was also delayed gradually but remarkably. The daily rhythm of body temperature was changed by the alteration of sleep-wake cycle. The body temperature began to decrease at the similar clock time as in the control but the decline during night awake period was less steep and the lowered body temperature persisted during sleep. The hormonal profiles during the days of shifted sleep/wake cycle suggest that plasma melatonin and TSH rhythms are basically regulated by an endogenous biological clock. The parallel phase shift of melatonin and TSH upon the change in sleep-wake cycle suggests that a common unitary pacemaker probably regulates these two rhythms. The reversal phase relationship between body temperature and melatonin suggests that melatonin may have a hypothermic effect on body temperature. The altered body temperature rhythm suggests that the awake status during night may inhibit the circadian decrease in body temperature and that sleep sustains the lowered body temperature. It is probable but uncertain that there ave causal relationships among sleep, melatonin, TSH, and body temperature.

A Comparative Study of Algorithms for Estimating Land Surface Temperature from MODIS Data

  • Suh, Myoung-Seok;Kim, So-Hee;Kang, Jeon-Ho
    • Korean Journal of Remote Sensing
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    • v.24 no.1
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    • pp.65-78
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    • 2008
  • This study compares the relative accuracy and consistency of four split-window land surface temperature (LST) algorithms (Becker and Li, Kerr et ai., Price, Ulivieri et al.) using 24 sets of Terra (Aqua)/Moderate Resolution Imaging Spectroradiometer (MODIS) data, observed ground grass temperature and air temperature over South Korea. The effective spectral emissivities of two thermal infrared bands have been retrieved by vegetation coverage method using the normalized difference vegetation index. The intercomparison results among the four LST algorithms show that the three algorithms (Becker-Li, Price, and Ulivieri et al.) show very similar performances. The LST estimated by the Becker and Li's algorithm is the highest, whereas that by the Kerr et al.'s algorithm is the lowest without regard to the geographic locations and seasons. The performance of four LST algorithms is significantly better during cold season (night) than warm season (day). And the LST derived from Terra/MODIS is closer to the observed LST than that of Aqua/MODIS. In general, the performances of Becker-Li and Ulivieri et al algorithms are systematically better than the others without regard to the day/night, seasons, and satellites. And the root mean square error and bias of Ulivieri et al. algorithm are consistently less than that of Becker-Li for the four seasons.

Estimation of nighttime aerosol optical thickness from Suomi-NPP DNB observations over small cities in Korea (Suomi-NPP위성 DNB관측을 이용한 우리나라 소도시에서의 야간 에어로졸 광학두께 추정)

  • Choo, Gyo-Hwang;Jeong, Myeong-Jae
    • Korean Journal of Remote Sensing
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    • v.32 no.2
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    • pp.73-86
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    • 2016
  • In this study, an algorithm to estimate Aerosol Optical Thickness (AOT) over small cities during nighttime has been developed by using the radiance from artificial light sources in small cities measured from Visible Infrared Imaging Radiometer Suite (VIIRS) sensor's Day/Night Band (DNB) aboard the Suomi-National Polar Partnership (Suomi-NPP) satellite. The algorithm is based on Beer's extinction law with the light sources from the artificial lights over small cities. AOT is retrieved for cloud-free pixels over individual cities, and cloud-screening was conducted by using the measurements from M-bands of VIIRS at infrared wavelengths. The retrieved nighttime AOT is compared with the aerosol products from MODerate resolution Imaging Spectroradiometer (MODIS) aboard Terra and Aqua satellites. As a result, the correlation coefficients over individual cities range from around 0.6 and 0.7 between the retrieved nighttime AOT and MODIS AOT with Root-Mean-Squared Difference (RMSD) ranged from 0.14 to 0.18. In addition, sensitivity tests were conducted for the factors affecting the nighttime AOT to estimate the range of uncertainty in the nighttime AOT retrievals. The results of this study indicate that it is promising to infer AOT using the DNB measaurements over small cities in Korea at night. After further development and refinement in the future, the developed retrieval algorithm is expected to produce nighttime aerosol information which is not operationally available over Korea.

The Demersal Fishes of Asan Bay -II. Diurnal and Seasonal Variation in Abundance and Species Composition- (아산만 저어류 -II. 종조성의 주야 및 계절변동-)

  • LEE Tae-Won;KIM Gwang-Cheon
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.2
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    • pp.103-114
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    • 1992
  • Diurnal and seasonal variation of demersal fishes of Asan Bay were studied using seasonal samples collected by an otter trawl from autumn 1989 to summer 1990. For each sampling period, three to five trawl hauls were completed to obtain day and night samples. Of 32 species identified, Chaturichthys stigmatias, Cynoglossus joyneri, Thrissa koreana, Repomuenus lunatus and Hexagrammos otakii accounted for $79.5\%$ of the individuals collected, and C. joyneri, T koreana, H. otakii, Raja kenojei and Kareius bicoloratus constituted $67.1\%$ of the biomass obtained. Apparently, larger number of individuals and greater biomass were collected in night hauls. However, there is no significant difference between day and night samples in community structure, mean abundance and body length of the dominant demersal species. The greatest numbers and biomass of fishes were collected in summer and the lowest in winter. The abundance of fishes in the study area were dependent upon seasonal effects such as temperature.

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