• Journal of People, Plants, and Environment
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• v.24 no.4
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• pp.355-363
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• 2021

Background and objective: This study was conducted on Forsythia velutina, a special plant, in Gyeongsangnam-do Arboretum under the Gyeongsangnam-do Forest Environment Research Institute, which is located in the southern part of Korea. Methods: The research aimed to analyze the flowering characteristics of the plant by calculating the optimal temperature and humidity according to the flowering time and flowering period for 8 years from 2010 to 2017 in order to provide basic data for bioclimate studies of endemic plants. Results: It was observed that the Forsythia velutina showed a life cycle from mid-March and to mid-November. Average growth period was 243 (± 6.5) days. In testing the reliability of a single variable according to the meteorological factors, the Cronbach's Alpha was 0.701, which indicates that the findings were relatively reliable. The average date of flowering was March 16 (SD = 5.8) and the average date on which blossoms fall was March 29 (SD = 5.2). A substantial difference in flowering period was observed from year to year 11 to 23 days, with an average of 16 days (± 4.7). The temperature and humidity in February to March, which affect the flowering, were 2.9-5.5℃, and 66.5-73.0%, respectively, and showed differences every year. Conclusion: The correlation between flowering time and meteorological factors was positive, and the highest daily temperature and average daily temperature had the highest significance. When establishing basic data on plant species for the conservation of endemic plants, the changes in life cycle events and weather conditions are identified. It is believed that it will be helpful in establishing a conservation strategy for the plant species in the future.

• Sleep Medicine and Psychophysiology
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• v.21 no.2
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• pp.51-60
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• 2014

A 'circadian rhythm' is a self-sustained biological rhythm (cycle) that repeats itself approximately every 24 hours. Circadian rhythms are generated by an internal clock, or pacemaker, and persist even in the absence of environmental time cues, collectively termed 'zeitgebers.' Although organisms generate circadian rhythms internally, they are entrained by environmental stimuli, particularly the light-dark cycle. Measurement of the endogenous melatonin rhythm provides relatively reliable surrogate way of assessing the timing of the internal circadian clock. Also, core body temperature and cortisol can be used as markers of circadian rhythms. The sleep-wake cycle, body temperature, and melatonin rhythm have a stable internal phase relationship in humans and other diurnal species. They play an important role in controlling daily behavioral rhythms including task performance, blood pressure, and synthesis and secretion of several hormones. In this review, we address not only the properties, methods of measurement, and markers of circadian rhythms, but also the physiological and psychological importance of human circadian rhythms.

• Korean Journal of Community Nutrition
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• v.3 no.2
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• pp.210-217
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• 1998

The purpose of this study was to examine changes in energy and macronutrient intakes during the premenstrual(days -10-1) and postmenstrual(days 5-14) phases. Thirty-two college female students recorded their food consumption and dietary patterns over 5 weeks from September 8 to October 12, 1997. Mean daily energy and macronutrient intakes and the percentage of energy intake from protein and carbohydrate were relatively consistent over the two menstrual cycle phases, but the energy intake from fat increased 1%(P<0.05)during the postmenstrual phase. Two different dietary patterns were identified by the shifts in energy intake between postmenstrual and premenstrual phases. Seventy five percent of subjects revealed a consistent pattern with the results of previous studies investigating food intake over the menstrual cycle, in which the premenstrual phase is associated with an increment in energy, carbohydrate, and protein intake. In contrast, energy, protein, and fat intakes increased during the postmenstrual phase in 25% of the subjects. We conclude that cyclical fluctuations in energy and macronutrient intakes occur in both postmenstrual and premenstrual dietary pattern groups across the two menstrual phased with the opposite directions.

• Journal of The Korean Society of Agricultural Engineers
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• v.54 no.1
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• pp.27-38
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• 2012

This study is to analyse the hydrological behavior of agricultural reservoir using CAT (Catchment hydrologic cycle Assessment Tool). The CAT is a water cycle analysis model in order to quantitatively assess the characteristics of the short/long-term changes in watershed. It supports the effective design of water cycle improvement facilities by supplementing the strengths and weaknesses of existing conceptual parameter-based lumped hydrologic models and physical parameter-based distributed hydrologic models. The CAT especially supports the analysis of runoff processes in paddy fields and reservoirs. To evaluate the impact of agricultural reservoir operation and irrigation water supply on long-term rainfall-runoff process, the CAT was applied to Idong experimental catchment, operated for research on the rural catchment characteristics and accumulated long term data by hydrological observation equipments since 2000. From the results of the main control points, Idong, Yongdeok and Misan reservoirs, the daily water levels of those points are consistent well with observed water levels, and the Nash-Sutcliffe model efficiencies were 0.32~0.89 (2001~2007) and correlation coefficients were 0.73~0.98.

• Journal of Embryo Transfer
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• v.24 no.2
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• pp.109-113
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• 2009

Serial ultrasonography was performed to measure the normal appearance of uterine during estrous cycle and to determine whether the unterine appearance was related to the sex hormone, progesterone and estrogen. The uterine appearances, shape, diameter and echogenicity were daily monitored with ultrasonography in 9 Miniature Schnauzer dogs undergoing II estrous cycles. During proestrus and estrous, the uterus became hypoechoic but developed hyperechoic luminal echo. In the longitudinal view, the shape of the uterus occasionally changed from rectangular to coiled or serpentine, compared to other stages of the cycle. The diameter of the uterus during proestrus and estrous was larger (range: 0.60${\sim}$0.86 mm) than other stages (range: 0.48${\sim}$0.62 mm) of the cycle. The rising estrogen concentrations (range: 14.51${\sim}$16.86 pg/ml) in plasma during proestrus correlated with changes in the uterus (p<0.05). Progesterone concentrations were 0.08${\sim}$0.15 ng/ml at the onset of proestrus, but rose 1.06${\sim}$1.26 ng/ml at the end of proestrus. There was no relation to progesterone concentration from onset of estrus (p>0.05). There was dramatical changes in normal uterus and sex hormone during estrous cycle. Especially, the appearance, shape and diameter of uterus were related to plasma estrogen concentration during proestrus, correlated with other stages of the cycle.

• Journal of People, Plants, and Environment
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• v.23 no.2
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• pp.179-189
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• 2020

In order to increase the indoor air purification effect of plants, plants need to be placed on 5-10% of indoor spaces. To increase the density and utilization of plants in indoor spaces, studies on bio-wall, a vertical green wall system, have been recently conducted. The purpose of this study was to investigate the growth characteristics of 7 indoor plants introduced to the system and their rooting zones at different irrigation cycles. This study was conducted to investigate a proper irrigation cycle for the continuous maintenance of bio-wall systems. The conditions of their growth environment were maintained as follows: light intensity, 20-50 μmol·m^-2·s^-1 PPFD; and temperature, 20 - 25℃. For fertilization, Hyponex diluted with water at the ratio of 1:1,000 was supplied to plants. Irrigation was treated at intervals of 1, 3, 5, and 7 days for 1 hour at a time. As a result, there was no significant difference in the growth of plants between different irrigation cycles. Dieffenbachia 'Marianne' showed a significant decrease in the number of leaves at the irrigation cycle of 7 days. In addition, the chlorophyll content was relatively low at the irrigation cycle of 7 days. In terms of the color of leaves, a decrease in L value and b value and an increase in a value were observed, resulting in changes in brightness and color. Ardisia pusilla 'Variegata' showed a slightly higher photosynthetic activity and stomatal conductance when it was watered every day and once per 5 days, while Epipremnum aureum showed a relatively higher photosynthetic activity and stomatal conductance at the irrigation cycle of 3 days. In the case of root activity, it was found that the longer irrigation cycle, the higher root activity compared to daily irrigation. The development of roots of Peperomia clusiifolia was promoted by watering at long intervals. However, in the case of Aglaonema 'Siam-Aurora', the total number of roots decreased at the interval of 7 days. In conclusion, a proper irrigation cycle for the sustainable maintenance of vertical bio-wall systems seems to be 3 days.

• Journal of Korean Society of Water and Wastewater
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• v.29 no.4
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• pp.447-457
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• 2015

Water cycle within the human civilization has become important with urbanization. To date, water cycle in the eco-system has been the focus in identifying the degree of water cycle in cities, but in practicality, water cycle within the human civilization system is taking on an increasing importance. While in recent years plans to reuse water have been implemented to restore water cycle in cities, the effect that such reuse has on the entire water cycle system has not been analyzed. The analysis on the effect that water reuse has on urban areas needs to be go beyond measuring the cost-savings and look at the changes brought about in the entire city's water cycle system. This study uses a SWAT model and water balance analysis to review the effects that water reuse has on changes occurring in the urban water cycle system by linking the water cycle within the eco-system with that within the human civilization system. The SWAT model to calculate the components of water cycle in the human civilization system showed that similar to measured data, the daily changes and accumulative data can be simulated. When the amount of water reuse increases in urban areas, the surface outflow, amount of sewer discharge and the discharged amount from sewage treatment plants decrease, leading to a change in water cycle within our human civilization system. The determinant coefficients for reduced surface outflow amount and reduced sewer discharge were 0.9164 and 0.9892, respectively, while the determinant coefficient for reduced discharge of sewage treatment plants was 0.9988. This indicates that with an increase in water reuse, surface flow, sewage and discharge from sewage treatment plants all saw a linear reduction.

• Journal of Astronomy and Space Sciences
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• v.23 no.3
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• pp.227-236
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• 2006

The fractal dimension is a quantitative parameter describing the characteristics of irregular time series. In this study, we use this parameter to analyze the irregular aspects of solar activity and to predict the maximum sunspot number in the following solar cycle by examining time series of the sunspot number. For this, we considered the daily sunspot number since 1850 from SIDC (Solar Influences Data analysis Center) and then estimated cycle variation of the fractal dimension by using Higuchi's method. We examined the relationship between this fractal dimension and the maximum monthly sunspot number in each solar cycle. As a result, we found that there is a strong inverse relationship between the fractal dimension and the maximum monthly sunspot number. By using this relation we predicted the maximum sunspot number in the solar cycle from the fractal dimension of the sunspot numbers during the solar activity increasing phase. The successful prediction is proven by a good correlation (r=0.89) between the observed and predicted maximum sunspot numbers in the solar cycles.

• Journal of the Korean Institute of Educational Facilities
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• v.14 no.4
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• pp.34-42
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• 2007

The investment of BTL(Build-Transfer-Lease) projects for the educational facilities has been increased since 2005. However, many trial errors and problems have been occurring due to the lack of inspection criteria in maintenance cost for the lift cycle of the facilities. Thus, purpose of this study is to derive regression equation for the daily inspection and the regular inspection through analysis of CAD data in order to set the inspection criteria. It is possible to calculate economical maintenance cost of BTL project in educational facilities using criteria of inspection time through the regression equation developed in this study.

• Proceedings of the KIEE Conference
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• 2000.07a
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• pp.334-336
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• 2000

In Korea, the CCGTs have been installed to about 25% of the total generating capacity. Generally CCGTs determine the System Marginal Prices(SMP) in Cost Based Generation Pool. So the scheduling of CCGTs is very important in daily generation scheduling. This paper describes the scheduling of CCGTs which considers the operating characteristics of them. We use lagrangian relaxation method which decomposes the unit committment problem into the subproblems of the individual unit. In the CCGT subproblem, we define the cost function of CCGT in two way. In Case study, the daily generation scheduling is performed using the data of Korean thermal system.