• Korean Journal of Mathematics
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• 제6권2호
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• pp.303-311
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• 1998

We study the conformally flat unit vector bundle $E_1$ of constant scalar curvature for the bundle ${\pi}:E^{n+2}{\rightarrow}M^n$ over an Einstein manifold M.

• 호남수학학술지
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• 제38권1호
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• pp.59-69
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• 2016

We classify conformally flat Kenmotsu 3-manifolds and classify conformally flat cosympletic 3-manifolds.

• 대한수학회지
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• 제32권3호
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• pp.519-529
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• 1995

Let M be a compact smooth manifold of dimension n and let E be a flat (complet) vector bundle over M of rank r.

• 대한수학회보
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• 제53권6호
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• pp.1879-1886
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• 2016

In this paper, we investigate domains having a flat piece in the boundary and find a sufficient condition for such a domain to be a cone.

• 대한수학회논문집
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• 제11권2호
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• pp.391-405
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• 1996

In this article, we calculate the cohomology groups of flat vector bundles on some manifolds.

• 대한수학회논문집
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• 제15권3호
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• pp.541-547
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• 2000

In this paper, we discuss various limit sets of projectively flat manifolds and relationship between them.

• 복식
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• 제66권3호
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• pp.1-17
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• 2016

This study examined and analyzed the women's jeogoris in the Seoul Gwangjang Market and Busan Jin Market. They study explored the items to look into the current state of the Jeogori patterns, as well as investigate the flat pattern jeogoris, including its source and aspects of change. Korean women's body figure has become more westernized, and the purpose of this study is to investigate the effects of this change on the traditional jeogoris. We hope to gather valuable data, which can be used to propose a new direction for designing hanbok in the future. The study methods are as follows: First, the types of jeogori patterns were examined. Second, the current state of jeogori patterns in the Seoul Gwangjang market and Jin market in Busan were analyzed to look into how the patterns have transitioned. And lastly, the reason for the origination of the flat pattern jeogori and the type of changes will be examined. Current study results show that two pattern types are being used: the flat composition jeogori and the flat pattern jeogori. Surveys show that more than 90 percent of the jeogoris in the Seoul Gwangjang Market are of the flat composition pattern variety, while more than 90 percent of jeogoris in the Busan Jin Market are of the flat pattern variety. In 1998, western-style dress designers in Busan introduced the flat pattern jeogoris, which were used to get rid of the wrinkles caused by the extra space, into the market after the financial crisis period in Korea, as a way to revitalize the market. This new pattern was popular among tea aficionados and traditional Korean musicians. It was exposed to the public via different mediums, such as TV programs, magazines, and brochures. Busan was the first to be exposed, and then it spread to Seoul. It also seems that the reduction of production cost caused the increase of the flat pattern jeogori.

• 한국습지학회지
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• 제14권3호
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• pp.375-384
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• 2012

강화 갯벌의 퇴적작용은 주변의 대규모 건설로 인하여 지난 20여년 동안 변화되어 왔다. 강화 갯벌 동부와 염하수로 하류에 위치한 동검 갯벌의 퇴적환경은 조류와 하구 순환의 변화에 의하여 영향을 받았다. 그 결과 동검 갯벌에 급격한 퇴적이 일어났다. 두 개의 코어 퇴적물 상부에 나타나는 실트-점토 호층 엽리 실트 퇴적상은 동검 갯벌에서 상대적으로 많은 퇴적이 있었음을 나타냈다. $^{210}Pb$ 분석에 의한 두 개 코어 시료의 퇴적률은 정점3에서 3.25cm/year와 정점 5에서 3.47cm/year 였다. 그러나 2010년부터 2012년까지의 단기 퇴적률은 대부분 1cm/year 미만으로 상대적으로 낮은 비율의 퇴적을 나타내고 있었다. 결과적으로, 동검 갯벌의 퇴적물은 2000년대에 인공구조물 건설에 의하여 급격히 퇴적되었다. 현재 동검 갯벌의 고도 증가는 계절 변화를 가진 상대적으로 낮은 퇴적률을 보여 주고 있다.

• 한국해양공학회지
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• 제21권2호
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• pp.42-49
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• 2007

It has been known that shallow-water regions, such as tidal flats, sea grass and sea weed beds have water purification capability, and they also serve as nursery grounds for many fishes. On the other hand, tidal flat areas are economically attractive sites for reclamation, to be used for developing industries. When developing shallow-water areas, we have to propose a plan to mitigate the environmental impact associated with such a development plan. However, it is difficult to estimate the affects on the ecosystem and water purification, and the literature related to this matter is insufficient. In order to evaluate the ability of coastal tidal flat and to predict the future changes, it is necessary to develop a reliable prediction technique and construction of data by using a field investigation. In this study, we carried out a numerical model test for the tidal flat ecosystem, using the pelagic system and the benthic system, simultaneously, in order to show a change in the tidal flat ecosystem. The flow of nitrogen, phosphorus and carbon has been identified as a primary consideration of marine ecosystem components, and the capability of water purification and the change of the tidal flat were predicted using this flow. In order to make a more reliable prediction, a field investigation to determine tide, current and creatures of the object coastal area has been done. The purification capability of this shallow-water region is estimated from the model results. According to the results of experiments, the tidal flat has a capability of water purification (Sink) of 11mgN/m2/day, but the other area has a load (Source) of 20mgN/m2/day. As a result, we could confirm that the tidal flat of an object coastal area plays an important role in water purification.

• 한국토양비료학회지
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• 제49권6호
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• pp.669-676
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• 2016

A field study was conducted to determine the runoff loss of N and P in small scale of red pepper field plots (10% slope), consisting of three different plots with black polyethylene vinyl mulching (mulching), ridge without mulching (ridge), and flat without ridge and mulching (flat). Composted manure and urea as a basal application were applied at rates of $20MT\;ha^{-1}$ and $93kg\;N\;ha^{-1}$, respectively. Urea at $189kg\;N\;ha^{-1}$ and fused phosphate at $67kg\;P_2O_5\;ha^{-1}$ were additionally applied on June 25 with different fertilization methods, broadcast application in flat plot and hole injection in ridge and mulching plots. Plant uptake of N and P was positively correlated with their respective concentrations in surface soil: mulching > ridge > flat plots. The runoff loss by soil erosion was higher in flat plot than ridge and mulching plot with contour line. Nitrate loss by the runoff water had no significant differences among three surface management practices, but the higher average value in ridge and mulching plots than flat plot. Especially, the flat plot had no phosphate loss during summer season. This is probably due to low labile P content in surface soil of flat plot. In the summation of soil and water loss, flat plot was higher in N and P loss than ridge and mulching plot with contour line. Nevertheless, the nitrate and phosphate loss by runoff water could be more important for non-point source management because the water could meet the river easier than eroded soil because of re-deposition around slope land.