• 환경위생공학
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• 제5권2호
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• pp.89-99
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• 1990

Morphology, anatomy and diurnal acid fluctuations were investigated monthly for the succulent C4 dicot Portulaca grandiflora Hook. growing under natural environmental conditions. Modified Kranz-Type sturcture and typical CAM-like cells were shown in leaves and stems, respectively. Values of indices of mesophyll succulence inleaves stems were 5.62 and 16.68, respectively. The number of stomata were 1476$\textrm{cm}^{-2}$ in leaves while the stomata in stems were not observed through growing seasons from spring to summer. However, on Sep. 16, 1981 in defoliate autumn season, stomata were begun to be produced for the first time in stems and the number were increased gradually to 216$\textrm{cm}^{-2}$ on Oct. 29. This feature can be interpreted as a seasonal plant dimorphism. P. grandiflora exhibited a diurnal fluctuation of titratable acidity in leaves and stems. Seasonal amplitudes of acid fluctuation in stems were as follows: 27 $\mu$eq./g.f.wt. on Sep. 21; 57$\mu$eq/g.f.wt. on Oct. 3; 80$\mu$eq./g.f.wt. on Oct. 21. Such the results in seasonal amplitude were able to consider due to decrease of light period and cool night air temperature according to change of season. Also, the naturally defoliated stems which had already stomata exhibited usual diurnal acid fluctuation, on the other hand the treated stems which possessed artificially closed stomata showed a few of acid fluctuation. Especially, stomata in stems are developed by seasonal dimorphism and activated stomata participate in CAM behavior of stems.

• 해양환경안전학회지
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• 제29권3호
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• pp.255-269
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• 2023

Surface water temperature of a bay (from the south to the north) increases in spring and summer, but decreases in autumn and winter. Due to shallow water depth, freshwater outflow, and weak current, the water temperature in the central to northern part of the bay is greatly affected by the land coast and air temperature, with large fluctuations. Water temperature variations are large in the north-east coast of the bay, but small in the south-west coast. The difference between water temperature and air temperature is greater in winter and in the south-central part of the bay than that in the north to the eastern coast of the bay where sea dykes are located. As the bay goes from south to north, the range of water temperature fluctuation and the phase show increases. When fresh water is released from the sea dike, the surrounding water temperature decreases and then rises, or rises and then falls. The first mode of empirical orthogonal function (EOF) represents seasonal variation of water temperature. The second mode represents the variability of water temperature gradient in east-west and north-south directions of the bay. In the first mode, the maximum and the minimum are shown in autumn and summer, respectively, consistent with seasonal distribution of surface water temperature variance. In the second mode, phases of the coast of Seosan~Boryeong and the east coast of Anmyeon Island are opposite to each other, bordering the center of the deep bay. Periodic fluctuation of the first mode time coefficient dominates in the one-day and half-day cycle. Its daily fluctuation pattern is similar to air temperature variation. Sea conditions and topographical characteristics excluding air temperature are factors contributing to the variation of the second mode time coefficient.

• 한국잠사곤충학회지
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• 제18권2호
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• pp.61-64
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• 1976

1. 발생소장은 기상환경 중 강우량 및 일조시수에 큰 영향을 받으며 8월초 밀도가 급증하여 하순에 Peak를 나타내었다. 2. 엽위별분포는 상부로부터 4-16엽이 분포하고 그 중 6-12위엽에 최대로 분포하였다. 3. Orthene, Metasystox의 방제효과가 우수하였다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2006년도 총회 및 춘계학술발표회
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• pp.68-71
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• 2006

Seasonal fluctuation of groundwater level by pumping amount and stream discharge at the riverbank filtrate site adjacent to the Nakdong River in Daesan-Myeon was characterized. Groundwater level fluctuation shows increase in wet season (June, July, August and September) and decrease in dry season (the other months). Seasonal variation of pumping amount shows similar trend to the groundwater fluctuation due to higher consumption of potable water in summer. The relation of specific capacity, Nakdong River and pumping quantity was analyzed. The logarithmic relationship between specific capacity and the stream discharge gives high correlation coefficient, 0.96. This fact indicates that the increase of stream discharge rate reduces the rate of drawdown in the pumping area in wet season.

• The Korean Journal of Ecology
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• 제13권1호
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• pp.25-32
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• 1990

The vertical distribution and seasonal fluctuation of soil microarthropods in the forests with different flora were investigated in this study. soil micrarthropods were concentrated as much as 71.8% in the first layer subsoil (0-5cm), 22.3% in the second layer subsoil (5-10cm), and 5.9% in the third layer subsoil (10-15cm) in the decreasing order. The population density in the first layer decreased slightly in winter while that of the second layer increased. However, the density in the first layer bounced back in the following spring. Seasonal fluctuations of population density were revealed "Two peak-Two valley type", that is, the densities were high in fall and spring, and low in winter and summer.nd summer.

• Journal of applied mathematics & informatics
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• 제26권3_4호
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• pp.615-625
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• 2008

A single item order level inventory model for perishable products is considered in which a constant fraction of on hand inventory spoils per unit time. Demand linearly depends on time. The fluctuation of demand is taken into account to determine minimum total cost of the system. Both discrete and continuous fluctuations are considered. The model is developed and solved analytically for infinite time horizon. A numerical example is presented for finite time horizon. Sensitivity analysis of the model is carried out.

• The Korean Journal of Ecology
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• 제18권1호
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• pp.137-146
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• 1995

Acer pseudo-sieboldianum, A. ginnala, A. negundo and A. saccharinum were selected as materials for the studies on the seasonal fluctuation of chlorophyll content and photosynthetic rates. In all the four species during the growing season except in October, the principal component that determined the total chlorophyll content was chlorophyll a. Content of chlorophyll b increased with leaf age, but that of chlorophyll a decreased. In contrast to A. saccharinum and A. pseudo-sieboldianum which showed their maximum chlorophyll content in June, A. negundo, which showed the highest chlorophyll content of the four species, exhibited its maximum chlorophyll content in July, whereas September in the case of A. ginnala. The fluctuation of chlorophyll content was similar to that of air temperature, and it increased till July. But chloprophyll content showed a significant relationship in early stage of leaf development, and there could be any interdependence between them in accordance with the seasonal change, no longer. In all four species light compensation points decreased in accordance with the seasonal change, and the maximum photosynthetic rates were obtained in August. Respiratory rates were shown no significant difference among species, and they decreased according to the adbance of season.

• 한국동물학회지
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• 제39권3호
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• pp.325-336
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• 1996

제주도 자연림에 서식하는 초파리 군집구조를 파악하기 위하여 19954년 5월부터 10월까지 두 곳의 자연림에서 초파리를 채집하고, 이들의 종 수도와 미수직분포의 계절적 변이를 조사하였다. 전체적으로 우점종은 Drosophila bizonata, D. curviceps, D. lutescens, D. angu leris, D. tsigana and D. immigrans in the annual collections 등 6종이었다. 이들 우점종의 계절적 변화 양상은 두 조사지에서 유사했다. 종다양성의 계절적 변동은 종풍부도(종수)보다는 균등도의 영향을 더 받는 것으로 나타났으며, 모든 우점종의 수도에서 계절적 변동은 단일 장점을 갖는 양상을 보였다. 우점종의 일부는 미수직 분포에서 두 조사지간에 차이를 나타냈다. 이러한 결과들은 수림에 서식하는 우점종들의 생식 시기를 달리함으로써 생태학적 지위의 중복을 피하며, 이드르ㅣ 미수직분포는 계절과 고도 차이에 따른 요인에 많은 영향을 받고 있음을 암시한다.

• 한국융합학회논문지
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• 제6권4호
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• pp.161-167
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• 2015

시계열 데이터를 예측하는 것은 매우 어려운 작업이다. 비선형적인 특성을 갖는 신호에서 얻어지는 데이터들이 불확실성을 가지고 있기 때문이다. 본 논문은 특정 시계열 데이터의 정확한 예측을 위하여 시계열 자료가 어떤 패턴에 따라 변화한다는 전제하에서 과거 자료들을 평균하여 미분으로써, 시계열 변화 패턴의 찾았다. 또한 미분 데이터의 반영 비율에 따라 특이성을 갖는 시계열데이터를 일반화하기 위하여 확률변수를 적용하였다. 순환변동과 계절변동을 소거하고, 불규칙 변동만을 추출하여 경향의 추세를 더한 예측값을 계산하게 된다. 이렇게 예측된 값은 이동평균과 단순이동평균에 의하여 가장 좋은 결과값을 갖는 알고리즘과 비교를 통하여 제안 알고리즘의 우수성을 입증하였다.

• 한국물환경학회지
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• 제20권4호
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• pp.352-356
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• 2004

Variations of water quality parameters were investigated for last 13 years in Han river. Deviation from 3 month moving average was suggested for the variation analysis. Many parameters of mainstream and tributaries showed similar monthly fluctuations. Suspended solid of mainstream showed higher fluctuation than that of tributaries due to summer flood. Contrarily, the organic parameters such as BOD, COD, and TN showed lower fluctuations in the mainstreams. The magnitude of deviation was in the order of pH < DO, COD, temp. < BOD, TN < TP, SS. Strong correlation was found in BOD data of adjacent sites. Main sites showed low deviation in comparison to adjacent common sites of mainstream (1:2.4). Mainstream showed low deviation in comparison to tributaries (1:1.7). Seasonal tendency of monthly BOD was confirmed using autocorrelation function. The deviation was in inverse proportion to the magnitude of BOD.