• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2020년도 학술발표회
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• pp.122-122
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• 2020

Urban flood simulation plays a vital role in national flood early warning, prevention and mitigation. In recent studies on 2-dimensional flood modeling, the integrated run-off inundation model is gaining grounds due to its ability to perform in greater computational efficiency. The adaptive quadtree shallow water numerical technique used in this model implements the adaptive mesh refinement (AMR) in this simulation, a procedure in which the grid resolution is refined automatically following the flood flow. The method discounts the necessity to create a whole domain mesh over a complex catchment area, which is one of the most time-consuming steps in flood simulation. This research applies the dynamic grid refinement method in simulating the recent extreme flood events in Metro Manila, Philippines. The rainfall events utilized were during Typhoon Ketsana 2009, and Southwest monsoon surges in 2012 and 2013. In order to much more visualize the urban flooding that incorporates the flow within buildings and high-elevation areas, Digital Surface Model (DSM) resolution of 5m was used in representing the ground elevation. Results were calibrated through the flood point validation data and compared to the present flood hazard maps used for policy making by the national government agency. The accuracy and efficiency of the method provides a strong front in making it commendable to use for early warning and flood inundation analysis for future similar flood events.

• Applied Microscopy
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• 제42권2호
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• pp.95-103
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• 2012

연잎효과는 연꽃의 잎에서 규명된 현상으로 표피세포에서 기원하는 미세구조에 의해 물방울이 잎 표면이나 내부조직에 침투하지 않고 경사면으로 흘러내리며 표면 위 먼지나 이물질을 함께 떨어지게 한다. 잎 표면을 항상 깨끗한 상태로 유지하는 자기정화 능력인 연잎효과에 대해서는 여러 영역에서 연구되고 다방면으로 응용되고 있으나 구조적인 측면에서 연잎을 생장단계별 또는 표피조직 부위별로 비교 조사한 연구는 거의 없는 실정이다. 이에 본 연구에서는 연잎과 줄기를 대상으로 생장단계별, 부위별 표피조직의 미세 표면구조를 연구하여 연잎효과 표면 특성을 조사하였다. 본 연구에서 조사된 연잎효과는 미세돌기와 왁스결정체가 발달한 잎의 상피조직에서만 나타나고, 왁스결정체만 발달한 하피 및 줄기의 표피조직에서는 확인되지 않았다. 이는 미세돌기의 발달이 연잎효과를 나타내는데 가장 중요한 요인이고, 왁스결정체가 돌기표면 위에 축적되면 연잎효과는 더 증가하는 것으로 밝혀졌다.

• 한국환경보건학회지
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• 제30권1호
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• pp.50-58
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• 2004

The present study was designed to evaluate primary production organic matter in basin of lake around by execution of total maximum daily loading. BOD influent loading of Uiam lake was 2,819 kg/day, which was less then 28.3 percent, total effuluent loading as 3,619 kg/day, in comparision with BOD, total nitrogen influent loading was 4,681 kg/day, which was less then 10.0 percent, total effuluent loading as 5,150 kg/day. But in case of total phosphors influent loading was 73.3 kg/day, which was more then 34.2 percent, total run off loading as 48.3 kg/day. The result of survey reduction plan of primary production organic matter in basin of lake around which objectives of abstract is as follows. First plan was reduction of primary production organic matter by moving the outlet of municipal wastewater treatment center from present place to lake downstream. Secondary plan was improvement by diffusion type of outlet municipal wastewater treatment center. The third plan was reduction of environmental impact by passing and storing of municipal wastewater. Finally plan was decline water surface level which was present hydrouric retention time was reduction from 7.6 day to 6.0 day per meter.

• 환경영향평가
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• 제16권1호
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• pp.79-87
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• 2007

The performance of a stream water quality analysis model depends upon many factors attributed to the geological characteristics of a watershed as well as the distribution behaviors of pollutant itself on a surface of watershed. Because the model run has to import the pollution load from the watershed as a boundary condition along an interface between a stream water body and a watershed, it has been used to introduce a pollution delivery coefficient to behalf of the boundary condition of load importation. Although a nonlinear regression model (NRM) was developed to cope with the limitation of a conventional empirical way, this an up-to-date study has also a limitation that it can't be applied where the pollution load washed off (assumed at a source) is less than that delivered (observed) in a stream. The objective of this study is to identify what causes the limitation of NRM and to suggest how we can purify the process to evaluate a pollution delivery coefficient using many field observed cases. As a major result, it was found what causes the pollution load delivered to becomes bigger than that assumed at the source. In addition, the pollution load discharged to a stream water body from a specific watershed was calculated more accurately.

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2006년도 Proceedings of ISRS 2006 PORSEC Volume II
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• pp.1019-1022
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• 2006

Satellite sea ice data from 1978 to the present reveal that the perennial ice (or ice that survives the summer) has been rapidly declining at almost 10% per decade. Warming due to increases in greenhouse gases in the atmosphere is now also being reflected in winter with drastic reductions in the maximum extent observed in 2005 and 2006. The retreat of the perennial ice also exposes more open water and has revealed an asymmetric distribution of chlorophyll a pigment concentration in the Arctic basin. Phytoplankton blooms are most dominant at high latitudes, partly on account of sea ice, but in the Arctic basin, it appears that pigment concentrations in the Eastern (Laptev Sea) Region are on the average three times higher than those in the Western (Beaufort Sea) Region. Such asymmetry suggests that despite favorable conditions provided by the melt of sea ice, there are other factors that affects the productivity of the region. The asymmetry is likely associated with much wider shelf areas in the East than in the West, with sea ice processes that inhibits the availability of nutrients near the surface in deep water regions, and river run-off that affects nutrient availability. The primary productivity in the pan-Arctic region have been estimated using the pigment concentrations and PAR derived from SeaWiFS data and the results show large seasonal as well as interannual variability during the 1998 to 2005 period. The data points towards increasing productivity for later years but with only 9 years of data it is too early to tell the overall effect of the sea ice retreat.

• 대한기계학회논문집
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• 제12권4호
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• pp.694-704
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• 1988

본 연구에서는 현장에서 흔히 수행되는 가공 후(post-process) 측정만을 이용 한 단일절삭(single-pass)으로써 공작물이 원하는 일정한 직경을 유지할 수 있다는 것 을 실험을 통해 검증해 보이고자 한다. 이와 같은 방식은 이미 보오링 작업 중 보오 링바의 노출 길이 변화에 따른 가공면의 내경 오차를 없애주기 위한 방법으로써 제시 된 바 있다. 즉 반복 최소 자승법(recursive least squares)으로 미리 가정된 절삭 조건과 공작물 처짐 사이의 관계식과 관련된 계수를 가공 후에 가공 공작물의 표면 측 정으로 매 번보정(update)시켜 줌으로써 일정 직경을 얻기위한 절삭조건을 결정하고자 한다.

• 한국환경복원기술학회지
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• 제8권1호
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• pp.10-16
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• 2005

This experiment was conducted to study on application of several Korean native plants by seed spray methods for cut slope revegetation, and possibility of replacement almost imported tall fescue seeds by native herbaceous plants. So, we investigated growth and covering rate after sowing native plants seeds at the artificial slope plots in Suwon and the rock exposed cut-slopes in Wonju city. Emergence rate after seed spray at artificial slopes were higher Elsholtzia splendens and Dianthus superbus var. longicalycinus, showing the highest in E. splendens. Also, E. splendens, D. superbus var. longicalycinus, and Agrostemma coronaria were possible to use for seed spray at the rock exposed cut-slopes. The plots of mixed native plants show more seasonal scenery than that of tall fescue. Soil surface run-off by Typhoon was less in plot sown native plants than those of lawn grass, resulting fresh weight of roots was heavier. Thus, we found that the mixed seed spray of several native herbaceous plants, E. splendens, D. superbus var. longicalycinus, and Agrostemma coronaria, were well covered the slopes as tall fescue.

• 한국물환경학회지
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• 제24권5호
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• pp.523-532
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• 2008

A phase II site investigation and feasibility study was conducted at a military mortar shooting range near the demilitarized zone (Kyunggi, South Korea) to assess the extent of contaminants migration to the nearby Imjin river in which a flood control dam is under construction. The results showed that silty-clay soils around target areas were co-contaminated with heavy metals (Cd, Cu, and Pb) and explosives (HMX, RDX, and TNT). The total amount of contaminant was estimated to be 497.1 kg-RDX, 20.6 kg-HMX, 1.4 kg-TNT, 35.2 kg-Cd, 4,331 kg-Cu, and 5,115 kg-Pb, respectively. Both heavy metals and explosives were almost equally distributed on each soil particle size fraction. Neither subsurface soil samples nor ground water samples showed signs of contamination above the environmental criteria. The major migration route of contaminants was soil particles in surface run-off during rain at which a mass discharge rate of 30.0 mg-RDX/hour was observed.

• 한국인쇄학회지
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• 제23권2호
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• pp.143-159
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• 2005

The printing could not expect the print effect of the specific character of a printing material. Specially, a property of the paper that we are aware of the substrate has controled printability as well as run ability. The objective of this study was to measure substrate properties by measuring the water receptivity in order to know the degree of the uniformity on surface of paper. Therefore, the water receptivity was measured by fluid bridge method. And then the physical properties of samples such as ink set-off, porosity and print mottle of domestic coated papers were measured by Tappi method. Accordingly, this study obtained the outcome of water receptivity. And then we could know that the relations between water receptivity and physical properties of the paper samples have correlations. There are many measurement equipments to find out print mottle by the measurement of the reflected density at this point in time. However, it is thought that the fluid bridge method is the most proper way to find out print mottle, though there are many other ways to figure out.

• 한국환경과학회지
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• 제10권2호
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• pp.159-166
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• 2001

We studied the appearance and proliferation of red tide organisms from March, 1998, to February, 1999, in the Jindong Bay. There were two red tide events during investigation, and we found that the dominant species Ceratium furca in May and Gymnodinium sanguineum in September, 1998. At surface, temperature and salinity showed 18.3~19.7$^{\circ}C$ and 30.6~30.9 psu in May and 25.6~27.$0^{\circ}C$, 28.0~28.5 psu in September, respectively. When the red tide occurred, the water mass stable. Dissolved inorganic nitrogen(DIN) and dissolved inorganic phosphate(DIP) in Jindong Bay showed seasonal variability. In May, the nitrogen was a limited nutrient in which the ratio of DIN versus DIP was less than 16 (Redfield ratio), while in September phosphate. During June to September, 1998, phosphate acted as a limited nutrient due to the increased river run-off from land. In May, chlorophyll-a, dissolved oxygen(DO) and chemical oxygen demand(COD) showed higher than 20$\mu\textrm{g}$/$\ell$, 10mg/$\ell$ and 5.0mg/$\ell$, respectively. In September, they showed in turns 100$\mu\textrm{g}$/$\ell$, 10mg/$\ell$ and 10mg/$\ell$, respectively.