• Proceedings of the Korea Water Resources Association Conference
• /
• 2022.05a
• /
• pp.248-248
• /
• 2022

Hwang(2015)은 불연속 지형을 지나는 천수 흐름의 수치 해석에서 불연속 전면에 의한 추력(thrust)에 주목하여 그 영향을 흐름률(flux) 계산에 반영하는 새로운 기법을 제시하였다. 이 기법 덕분에 수심 적분 모형으로도 계단이나 보와 같이 직립한 하천 구조물의 불연속면을 경사로 완화하지 않고 직접 모의할 수 있다. 직립 측면 위어 실험에 Hwang(2015)의 기법이 적용됨으로써 연직면을 경사면으로 완화하여야 하는 기존의 수심 적분 모형에 비해 계산 격자 개수가 53%로 줄었다(Hwang, 2019). Hwang(2019)은 기존 모형과 비교를 통해, 정확도를 어느 정도 유지하면서도, 소요된 계산 시간이 20%에 불과하다고 주장하였다. 여기에서는 보다 다양한 직립 광정 위어 실험에 적용하여 수심 적분 모형에 의한 월류량을 검토하고자 한다.

• Journal of the Korean Geographical Society
• /
• v.38 no.2
• /
• pp.184-205
• /
• 2003

Sustainable Development(SD) is an important concept for the future of the coastal area, and for development of fishing villages. Since 1992 UN Conference on Environment and Development in Rio de Janeiro many governments and local authorities throughout the world have been engaged in preparing and implementing $\ulcorner$Agenda 21$\lrcorner$. Many projects which previously would have been identified as environmental protection are now presented under the banner of sustainable development. Integrated Coastal Management (ICM) is an extension of sustainable development. ICM was presented as a framework for resolution of coastal use conflicts. The aim of the present paper is to assess sustainable development potential of fishing villages in Cheonsu Bay Region according to implementation of ICM. Cheonsu Bay Region was known as one of the productive fishing grounds and Cheonsu Bay Region preserved unique characteristics of traditional fishing villages. But this region is now experiencing many changes through the massive reclamation projects like Seosan A B Project. After a brief overview of concepts and history of SD and ICM, the reclamation process and its impacts on both fishery and fishing communities in Cheonsu Bay Region are discussed. According to their changing environmental and socio-economic characteristics after the reclamation, ca 35 representative coastal villages in this region can be classified into 5 types. Many coastal villages shows diversity in their economic activities, as tourism and recreation function becomes more and more important in this region. In present-day Cheonsu Bay Region, it is possible to differentiate fishing village cooperatives(FVO) with high potential of sustainable fishery development, FVOs with medium potential, FVOs with low potential on the basis of 14 selected indicators.

• Journal of the Korean Society of Marine Environment & Safety
• /
• v.22 no.7
• /
• pp.854-862
• /
• 2016

In summer 2010, we measured the concentration of dissolved oxygen (DO) and nutrients in the water collected at the bottom of Cheonsu Bay, off the west coast of Korea. We also measured nutrient fluxes across the sediment-water interface by deploying a fully-automated benthic lander, which collected time-series water samples inside a benthic chamber. We confirmed on-going hypoxia in the northern parts of the bay where polluted lake water was discharged. DO content in the water at the bottom was 2 mg/l, compared to 5 mg/l at the mouth of the bay in the south. Nutrient concentrations showed a trend that was opposite to that of DO. The variation of N/P ratios implies phosphate desorption and a release of nutrients caused by hypoxia. The organic carbon oxidation rate and oxygen consumption rate in the northern parts of the bay were about twice as fast as those at the mouth of the bay. Benthic fluxes of nutrients in the northern part of the bay were 4 to 6 times higher than those at the mouth. Our results imply that it is important to understand the role of hypoxia events to make an accurate estimation of material fluxes across the sediment-water interface.

• Industry Promotion Research
• /
• v.7 no.1
• /
• pp.81-87
• /
• 2022

This study used a method of comparing and analyzing various editions of Jeokcheonsu, and aims to confirm why different views have arisen on commentaries that differ according to the perspective of one original text, which interpretation is more valid among them. The biggest part of the misunderstanding of Myeongri theory in Jeokcheonsu is Kyeokguk theory. Jeokcheonsu does not set a high value on Kyeokguk, and it is highly regarded as the Myeongri classics that emphasizes Eokbuyongsin. However, as a result of classifying the original text by theory, we can see there are about 5 sentences that directly mention Eokbu theory, but 9 sentences that explain Kyeokguk theory and 15 sentences if we include the sentences that explain Jonggyeok and Hwagyeok. Even looking that metaphoric speech is mainly used, it is also clear that it's not a book written to be read by a beginner of Myeongri. This is Myeongri texts written to convey more profound logic and enlightenment to a person who has sufficient knowledge by having learned the principle of Myeongri. A single sentence of 'Jaegwaninsubunpyeonjeong Gyeomronsiksanggyeokgukjeong' would have been sufficient to explain the Kyeokguk theory, because it's written on the assumption of the reader's level. Among the later commentaries about the theory of Myeongri contained in Jeokcheosu, 4 persons'commentaries on the original text of 'Palkyeok', 'Gwansal', Sangkwan', 'Wolryeong', 'Saengsi', 'Cheongtak' related to Kyeokguk theory was compared and analyzed.

• Proceedings of KOSOMES biannual meeting
• /
• 2018.06a
• /
• pp.205-205
• /
• 2018

• Proceedings of the Korea Contents Association Conference
• /
• 2011.05a
• /
• pp.423-424
• /
• 2011

Lax-Wendroff 기법을 기반의 천수방정식에 대한 유한요소 모형을 낙동강 상류부 단호교 지역에 적용하였다. 모형의 검증을 위하여 이동경계에 대한 Thacker (1981)의 정확해와 침수-노출 기법(wet-dry scheme)을 이용한 본 모형의 수치해를 비교하여 대체로 잘 일치함을 알게 되었다. 또한, U자형 만곡부를 포함한 수로의 흐름에 적용하여, 기존의 수리실험 결과, 수치모의 결과와 비교하고, 모형의 적용 가능성을 확인하였다. 낙동강 상류지역에 위치한 단호교 지역에 본 모형을 적용하고, 이를 기존 유한차분법에 의한 수치해와 비교하였다.

• Journal of Ocean Engineering and Technology
• /
• v.19 no.2 s.63
• /
• pp.29-33
• /
• 2005

The accuracy of predicting wave transformation in the nearshore is very important to wave hydrodynamics, sediment transport, and design of coastal structures. Numerical experiments are conducted to identify the shoaling and breaking characteristics of a fully nonlinear Boussinesq equation-based model. Simulated shoaling showed good agreement with the Shouto's formula, and the results of the breaking experiment agreed well with experimented data, over several beach profile.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 2000.09a
• /
• pp.149-154
• /
• 2000

파랑은 먼바다에서 주로 바람에 의하여 생성되어 천해로 전파되어 오면서 천수, 굴절, 회절, 반사, 중첩의 여러 가지 변형 과정을 거친다. 이 변형 과정 가운데 바닥의 영향으로 발생하는 것은 천수, 굴절, 반사이고 파랑간에 발생하는 것은 회절, 중첩이다. 수심이 파장의 1/2보다 작은 경우 바닥의 영향을 받게 되는데 이 해역이 중간수심해와 천해에 해당한다. 파랑변형모형은 파향선추적법부터 시작된다. (중략)

• 한국방재학회:학술대회논문집
• /
• 2010.02a
• /
• pp.107.2-107.2
• /
• 2010

본 연구에서는 지진해일의 전파 과정을 모의함에 있어 선형 천수방정식의 수치분산을 이용하는 기법이 아닌 선형 Boussinesq 방정식을 직접 차분하는 유한차분기법을 제안하였다. 기법의 정확성을 검증하기 위하여 Gauss 분포의 초기 자유수면변위를 갖는 문제에 착용하여 선형 Boussinesq 방정식의 해석해와 비교하였다. 그 결과 기존의 선형 천수방정식을 차분화한 수치모형에 비하여 정확한 결과를 제공하였고 분산보정기법을 이용한 수치모형과 동일한 정확도를 보였으나 본 수치모형을 이용했을 때 계산 효율이 개선되었다.

• Proceedings of the Korean Society of Coastal and Ocean Engineers Conference
• /
• 1998.09a
• /
• pp.31-35
• /
• 1998

지진해일 수치해석시 일반적으로 사용되어오던 Shuto의 유한차분모형(Goto ＆ Shuto, 1983)은, 천수방정식을 사용하고 파의 분산효과는 수치오차를 이용하여 고려하므로, 정해진 계산시간간격($\Delta$t)에 대해 수심에 따라 격자간격을 적절히 선택하여야 한다. 또한 Shuto 모형은 leap-frag 기법을 사용하므로, 격자 및 계산시간간격이 심해에서 수치분산을 위한 조건을 만족시켰다 할지라도, 천수화에 의해 파장이 점점 작아져 파수(k)가 $\pi$/$\Delta$x가 되는 수심(2$\Delta$x wave)에 이르면 파가 더 이상 진행하지 못하고 반사하게 되므로 실제 현상과는 다른 결과를 보이게 된다. (중략)