• 교육시설
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• 제14권4호
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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.

• Journal of Astronomy and Space Sciences
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• 제23권3호
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• pp.227-236
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• 2006

프랙탈 차원은 연속적으로 관측된 불규칙한 자료의 성질을 정량적으로 표현하는 파라메터이다. 본 연구에서는 프랙탈 차원을 이용하여 태양 흑점수의 불규칙한 변동을 분석하고 다가오는 태양주기의 최대흑점수를 예측하였다. 이를 위하여 우리는 SIDC(Solar Influences Data analysis Center)에서 제공하는 1850년부터 2004년까지의 일일흑점수를 이용하여 Higuchi의 방법으로 각 태양주기의 프랙탈 차원을 결정하고 같은 태양주기 동안의 최대 월평균 흑점수와 비교하였다. 그 결과 프랙탈 차원과 최대 월평균 흑점수는 강한 역비례 관계를 보였다. 이러한 관계를 이용하여 태양활동 극소기부터 활동이 증가되는 기간인 4년동안의 흑점수만을 이용하여 프랙탈 차원을 구하고 다가올 극대기의 최대 월평균 흑점수를 예측한 결과 관측된 최대흑점수와 0.89의 좋은 상관관계를 보였다.

• Journal of Astronomy and Space Sciences
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• 제30권4호
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• pp.241-246
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• 2013

We have investigated drought periodicities occurred in Seoul to find out any indication of relationship between drought in Korea and solar activities. It is motivated, in view of solar-terrestrial connection, to search for an example of extreme weather condition controlled by solar activity. The periodicity of drought in Seoul has been re-examined using the wavelet transform technique as the consensus is not achieved yet. The reason we have chosen Seoul is because daily precipitation was recorded for longer than 200 years, which meets our requirement that analyses of drought frequency demand long-term historical data to ensure reliable estimates. We have examined three types of time series of the Effective Drought Index (EDI). We have directly analyzed EDI time series in the first place. And we have constructed and analyzed time series of histogram in which the number of days whose EDI is less than -1.5 for a given month of the year is given as a function of time, and one in which the number of occasions where EDI values of three consecutive days are all less than -1.5 is given as a function of time. All the time series data sets we analyzed are periodic. Apart from the annual cycle due to seasonal variations, periodicities shorter than the 11 year sunspot cycle, ~ 3, ~ 4, ~ 6 years, have been confirmed. Periodicities to which theses short periodicities (shorter than Hale period) may be corresponding are not yet known. Longer periodicities possibly related to Gleissberg cycles, ~ 55, ~ 120 years, can be also seen. However, periodicity comparable to the 11 year solar cycle seems absent in both EDI and the constructed data sets.

• 수면정신생리
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• 제21권2호
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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.

• 한국건설관리학회논문집
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• 제6권3호
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• pp.100-110
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• 2005

건설 프로젝트가 더욱 복잡해지고 대형화함에 따라 정보의 양이 기하급수적으로 증가하고 있는데, 이로 인하여 프로젝트 생애주기간 실적정보를 관리하기 위한 정보 시스템이 필요하다. 특히, 작업일보 시스템은 가장 세부적인 수준에서 다양한 실적정보를 추적 관리할 수 있다는 점에서 매우 중요하다. 그러나 작업 일보 시스템의 프로세스가 시간이 많이 걸리며, 중복업무가 많고, 수집되는 정보표현의 모호성 등으로 인하여 많은 한계를 가지고 있었다. 따라서 본 연구에서는 실적정보를 수집하고 작업일보를 관리하는 프로세스를 향상시키는 것을 목적으로 To-Be 프로세스 모델을 구축하고 이를 검증하기 위해 작업일보 시스템을 개발하였다. 개발된 시스템은 interactive task generator와 작업일보관리 module로 구성되어있으며, 실제 건설프로젝트에서 성공적으로 시험되었다. 이 논문에서는 프로세스 분석, 정보모델 구축, 시스템 특징 등을 포함한 시스템 개발과정이 기술되어 있으며 연구결과와 개선효과도 논의되었다.

• Animal cells and systems
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• 제6권3호
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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.

• Communications for Statistical Applications and Methods
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• 제29권3호
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• pp.353-371
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• 2022

This paper analyzes death counts after World War II of several countries to identify and to compare their stochastic structures. The stochastic structures that this paper entertains are three structural time series models, a local level with a random walk model, a fixed local linear trend model and a local linear trend model. The structural time series models assume that a time series can be formulated directly with the unobserved components such as trend, slope, seasonal, cycle and daily effect. Random effect of each unobserved component is characterized by its own stochastic structure and a distribution of its irregular component. The structural time series models use the Kalman filter to estimate unknown parameters of a stochastic model, to predict future data, and to do filtering data. This paper identifies the best-fitted stochastic model for three types of death counts (Female, Male and Total) of each country. Two diagnostic procedures are used to check the validity of fitted models. Three criteria, AIC, BIC and SSPE are used to select the best-fitted valid stochastic model for each type of death counts of each country.

• Animal Bioscience
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• 제34권3_spc호
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• pp.354-362
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• 2021

Broiler chickens grow rapidly, and their nutrient requirements change daily. However, broilers are fed three to five diet phases, meaning nutrients are under or oversupplied throughout production. Increasing diet phases improves production efficiency as there is less time in the production cycle that nutrients are in under or over-supply. Nevertheless, the process of administering four or more diets is costly and often impractical. New technologies are now available to blend feed to match the daily nutrient requirements of broilers. Thus, the aim of this review is to evaluate previous studies measuring the impact of increasing feed phases on nutrient utilisation and growth performance, and review recent studies taking this concept to the extreme; precision nutrition - feeding a new diet for each day of the production cycle. This review will also discuss how modern precision feeding technologies have been utilised and the potential that new technologies may bring to the poultry industry. The development of a precision nutrition regime which targets daily requirements by blending dietary components on farm is anticipated to improve the efficiency of production, reduce production cost and therefore improve sustainability of the industry. There is also potential for precision feeding technology along with precision nutrition strategies to deliver a plethora of other management and economic benefits. These include increased fluidity to cope with sudden environmental or market changes, and the ability to alter diets on a farm by farm level in a large, integrated operation. Thus, the future possibilities and practical implications for such technologies to generate a paradigm shift in feed formulation within the poultry industry to meet the rising demand for animal protein is also discussed.

• 인간식물환경학회지
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• 제23권2호
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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 Astronomy and Space Sciences
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• 제15권1호
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• pp.197-208
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• 1998

Ground track manintenance maneuver simulations for the KOMPSAT spacecraft are performed for three and half years. Both longitude targeting and time targeting strate-gies are applied for in-plane maneuvers. The nominal longitude bands of maneuvers for $\pm5km$ and $\pm10km$ are applied for the longitude targeting and the 21-day maneuver time duration is used for the time targeting. Daily solar flux values for the simulation period are derived from the previous solar cycle values. Atmospheric drag formula for the KOMPSAT orbit altitude is derived from Jacchia model using polynomial and sinusoidal curve fitting. Total required delta velocity and proper time between successive maneuvers are estimated during ground track maintenance maneuver simulations.