• Journal of the Korean earth science society
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• v.21 no.2
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• pp.128-136
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• 2000

To understand the variation and transport pattern of suspended matters, salinity, tidal current and suspended matters in semiclosed Muan Bay have been monitored during winter and summer. The suspended matters show considerably seasonal variations with low concentration and homogeneity in the water column during winter season, but with high concentration and layering during summer season. Particularly, during summer season, the freshwater and the suspended matters influxed by the gate operation of the Youngsan River sea-dike are transported northward in accordance with the would flow into the inner-bay by relaxed flood currents after the construction of sea-dike and sea-walls in the Mokpo coastal zone. But, in the south bay-mouth, those matters outflow through the bay-mouth, resulting from tidal ebb dominance and asymmetry in the west bay-mouth. The residual suspended matter flux is much higher in the south bay-mouth(-0.0955kg/m ${\cdot}$ sec) than that of west bay-mouth(0.0078kg1m ${\cdot}$ sec). Accordingly, The Muan Bay is interpreted as erosion-dominated environments, and the erosion somewhat progresses in the intertidal flat of the bay.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.971-976
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• 2004

하천유지를 위한 하천내 최소유량의 충족은 사실상 환경문제에 제공되는 것으로서 기본적으로 하천변 수생식물의 생태계 서식처를 유지하거나 복원하기 위해 제공된다. 또한 하천유지유량은 하천의 고유종 동${\cdot}$식물을 보전하고, 아름다운 하천에 대한 심미적 질을 유지하며 여가활동 및 상업적 어획고를 최대로 늘릴 수 있거나 과학적 또는 문화적 관심사의 특성을 보호하는 기능을 위한 목적으로도 제공된다. 그러므로 생태학적인 하천유지유량 차원에서 무엇보다 중요한 것은 충분한 물을 확보하고 쾌적한 하천을 유지할 수 있는 맑은 물을 하천에 흐르도록 하는 것이다. 이와 더불어 하천의 생태학적인 측면에서는 서식지 보호를 고려한 계획이 뒷받침되어야 할 것이다. 기존의 개발은 하천정비, 골재채취, 수중 보와 하구 둑 등 하천시설물 건설, 그리고 댐 및 교량건설 등 인위적인 요인에 의하여 하천환경이 심각하게 변화는 경우가 많다. 특히 댐 건설로 인해 하류지역에 수리학적 변화와 하상 변동 등이 발생하고, 이로 인하여 생태계의 변화를 초래하기도 한다. 따라서 본 연구에서는 금강 최상류에 건설된 용담다목적댐에 의해 인위적으로 하천유입량이 감소하고 이로 인해 발생할 수 있는 수리학적 변화를 모의하여 댐 건설이 금강 상류에 미치는 영향을 분석하고자 한다. 이를 위해 2차원 유한요소모형을 이용하였으며, 댐 건설전 자연유출량 및 댐 건설후 하천유지유량에 의한 하천의 건조면적, 습지면적을 산정하였다. 또한 하천의 한계소류력과 하도를 형성하는 재료에 따라 바닥면 전단응력을 산정하여 그 차(差)를 활용하여 유량에 따른 유사이송현황을 모의하였다. 모의된 결과를 visual하게 표현하고자 GIS 기법을 이용하여 주요구간에 대한 유사이송현황을 도시하였다.유역의 고도차를 이용한 흐름특성 분석을 위해 수치고도자료를 이용하여 유역흐름특성을 분석할 수 있는 TOPAZ(Topographic PArameteri-Zation) 프로그램을 이용하였다. TOPAZ 프로그램을 통해 분석된 각 격자별 분포형 수문 매개변수는 적합한 관계식을 통해 분포형 유출량을 모의하는데 적용된다.다 정확한 유입량 예측이 가능할 것으로 사료된다.이 작은 오차를 발생하였으며, 전체적으로 퍼프 모형이 입자모형보다는 훨씬 적은 수의 계산을 통해서도 작은 오차를 나타낼 수 있다는 것을 알 수 있었다. 그러나 Gaussian 분포를 갖는 퍼프모형은 전단흐름에서의 긴 유선형 농도분포를 모의할 수 없었고, 이에 관한 오차는 전단계수가 증가함에 따라 비선형적으로 증가하였다. 향후, 보다 다양한 흐름영역에서 장${\cdot}$단점 분석 및 오차해석을 수행한 후에 각각의 Lagrangian 모형의 장점만을 갖는 모형결합 방법을 제시할 수 있을 것으로 판단된다.mm/$m^{2}$로 감소한 소견을 보였다. 승모판 성형술은 전 승모판엽 탈출증이 있는 두 환아에서 동시에 시행하였다. 수술 후 1년 내 시행한 심초음파에서 모든 환아에서 단지 경등도 이하의 승모판 폐쇄 부전 소견을 보였다. 수술 후 조기 사망은 없었으며, 합병증으로는 유미흉이 한 명에서 있었다. 술 후 10개월째 허혈성 확장성 심근증이 호전되지 않아 Dor 술식을 시행한 후 사망한 예를 제외한 나머지 6명은 특이 증상 없이 정상 생활 중이다 결론: 좌관상동맥 페동맥이상 기시증은 드물기는 하나, 영유아기에 심근경색 및 허혈성 심근증 또는 선천성 승모판 폐쇄 부전등을 초래하는 심각한 선천성 심질환이다. 그러나 진단 즉시 직접 좌관상동맥-대동맥 이식술로 수술

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.6 no.4
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• pp.283-296
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• 2008

The numerical simulations for groundwater flow were carried out to support the input parameters for safety assessment in LILW repository site. As the input parameters for safety assessment, the groundwater flux into the underground facilities during construction, flow rate through the disposal silo after closure of disposal silo and flow pathway from the disposal silo to discharge area were analyzed using the 10 cases groundwater flow simulations. From the total 10 numerical simulation results, the statistics of estimated output were similar to among 10 cases. In some cases, the analyzed input parameters were strongly governed by locally existed high permeable fracture zone at radioactive waste disposed depth. Indeed, numerical simulation for well scenario as a human intrusion scenario was carried out using the hydraulically severe case model. Using the results of well scenario, the input parameters for safety assessment were also obtained through the numerical simulation.

• The Korean Journal of Malacology
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• v.28 no.3
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• pp.187-196
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• 2012

Recently, for the purpose of constructing artificial ecosystem, the public aquarium and experimental mesocosm systems are receiving attention. To design and establish an aquarium and mesocosm system, there is need of several materials for simulating the environment, such as sediments, rocks, and plants. Expecially for sessile mollusks, there must be proper materials to which sessile invertebrates can adhere. Nowadays, many aquariums and mesocosm systems are using dead coral skeletons for sessile mollusks. This study was proceeded to have data on the effect of dead coral skeletons on water qualities with the experiment on the environmental factors. For this purpose, I made glass tank for experiment, chose two types of dead coral skeletons imported from the Indonesia and observed the change of water qualities and decomposition efficiency of TAN (total ammonia-nitrogen), nitrite ($NO_2{^-}$) and nitrate ($NO_3{^-}$). As a result, the lager the surface area was, the more TAN, nitrite and nitrate decomposition rate increased. In addition, coral skeletons covered with crustose algae and bacteria in the tank showed faster TAN, nitrite and nitrate removal rate and stabilization. Accordingly, this experiment suggested that dead coral skeletons could be used as a sub filter for the closed system as well as an adhering plate.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3345-3350
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• 2014

We investigated to assess the relationships between the major nutrients and phytoplankton dynamics during the spring season in 2010 and 2011 at 23 stations in Jinhae Bay, Korea. The bay is divided into four different zones based on pollutant sources and geographical characteristics. Nutrient limitation (>80%) was significant in Zone II, which is located in central bay and is influenced by the water well mixed from outer bay. The limited nutrient was followed in Zone III and IV that was occupying between 17% and 83%. However, the low levels are being kept below 35% in Zone I, which is characterized by the semi-enclosed eutrophic area of Masan and Haegam bays. Based on the PCA (principle component analysis) analysis, the nitrogen (N) sources in 2010 were particularly dominant and it may be due to the water mixing and wastewater formed from bottom layers and sewage. In 2011, major nutrients including nitrogen, silicon and phosphorus were dominant in the bay and are supplied by the river discharge after rainfalls with low salinity conditions. In particular, the N nutrients being supplied in 2010 are correlated with pennate diatoms Pseudo-nitzchia spp. and is not related to the phytoplankton population densities in 2011. The present study suggests that N sources play an important role in the proliferation of diatom, and the rapid nutrient uptakes by them are potential nutrient limitation factors in the bay.

• Water for future
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• v.26 no.1
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• pp.93-101
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• 1993

Because of the Keumkangsan-Dam and the Peace-Dam constructed in recent years, it is expected that the peak flood discharge and the peak flood stage at the Hwachun-Dam site have been changed. In this study, two methods were used to simulate and compare the effects of the upstream dam construction on the change of the discharge and the stage. One is the storage function method widely used for the hydrological routing in this country. The other is the DWOPER (Dynamic Wave Operational Model) package developed by the U.S. NWS for the hydraulic routing. Flood routing simulations have been performed on four different scenarios:1) Before the construction of the Keumkangsan-Dam and the peace-Dam, 2) The exclusion of the Keumkangsan-Dam watershed (before the construction of the Peace-Dam), 3) The exclusion of the Keumkangsan-Dam watershed (after the construction of the Peace-Dam), 4) The exclusion of the Peace-Dam watershed. The results of the four test cases from the two methods show that the peak flood discharge and the peak flood stage at the Hwachun-Dam site are reduced due to the construction of the Peace-Dam. From these findings, it is suggested that the operational criteria for the optimal dam-operation of the hwachun-Dam need to be modified.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.294-294
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• 2020

연안표사는 해안의 정선이 후퇴해 침식이 심각해지는 한편, 항만·어항에서는 토사가 퇴적되어 선박이나 어선의 항로나 정박지 매몰로 선박의 항행 및 어업 활동에 지장을 초래하며 하천 하구부에서는 하구 폐쇄로 치수상의 문제점 등이 발생한다. 항만과 어항 관리자는 항로나 정박지의 매몰 대책에 대한 검토와 해안 관리자는 해안 보전 대책에 초점을 맞춰 제각기 목적을 위한 대책 검토를 수행하고 있다. 이처럼 매년 적지 않은 비용이 소요됨에도 불구하고 뚜렷하고 효과적인 대책 없이 연안에 인위적인 변화를 발생시켜 어디에선 모래가 퇴적되고 그 영향에 따라 또 다른 곳에서는 침식되는 악순환이 반복되고 있다. 연안침식 방지를 위한 대책을 구축하기 위해서는 어느 한 곳에 중점적인 대책이 아닌 표사계 전체의 관점에서 상호 간의 간섭 효과를 고려한 통합적인 관점으로부터 대책을 강구해야 할 것이다. 연안지역에서의 표사수지는 산지, 댐, 하천, 해안 등 각각의 영역으로부터 유입 및 유출에 따라 안정된 해안이 조성된다. 하지만 환경적 및 인위적 변화에 따라 안정된 표사수지는 파괴되며 이 영향에 따라 표사의 이동이 발생한다. 지금까지의 토사관리는 각각의 영역에서 재해저감 및 토사관리를 위한 여러 대책의 효과가 나타나고 있으나 통합적인 토사관리에 있어 상호간의 피드백이 단절되어 연안역에서 발생하는 침식에 대한 정확한 원인 규명에 많은 어려움과 문제점이 발생하고 있다. 이처럼 통합적인 연안침식 관리를 위해서는 연안역으로 유입되는 토사의 이동 메커니즘 규명이 매우 중요하며 이를 바탕으로 정확한 유사량 산정을 통해 적절한 대책을 마련할 수 있다. 또한, 지역적 특징이 강한 우리나라에서는 통합적인 연안관리를 위한 구체적인 방안 검토가 이루어지고 있지 않지만, 일본에서는 지속적인 관측과 모니터링 조사를 통해 체계적인 관리를 수행하고 있다. 따라서 본 연구에서는 일본에서 진행 중인 통합적인 토사관리 가이드라인에 따른 토사관리의 구체적인 방법과 그에 따른 정선변화 및 표수사지 체계를 산정하였다.

• Journal of Chest Surgery
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• v.38 no.2 s.247
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• pp.152-156
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• 2005

Background: Occlusive complications after arterial revascularization are difficult to treat and have high recurrence rate. This study was performed to establish an effective treatment modality and to evaluate the factors affecting the occlusive complications by analysis of clinical data. Material and Method: During the period of 5 years. 33 patients (55 reoperations) were studied at the Department of Thoracic and Cardiovascular Surgery, Pusan National University Hospital following 173 arterial revascularization surgeries. The clinical characteristics, operating methods, the time intervals of reoperation, used graft, and the results of treatment were evaluated retrospectively. Result: All the patients were men except one and the mean age was 63.5 years old. The mean time internal from first operation to reoperation was 11.9 months. The cause of arterial occlusive diseases were 28 atherosclerosis and 5 Burger's diseases, Associated diseases were Hypertension $(57.6\%)$, Diabetes mellitus $(33.3\%)$, heart failure $(18.2\%)$, and so on. The mean rate of reoperation was 1.67 times and the most common type of first operation was femoro-popliteal bypass grafting $(57.6\%)$. The graft that used revascularization surgery were 25 cases of PTFE and 6 case were Dacron. There was no statistical difference between two groups. The kinds of reoperations were thrombectomy in 20 cases, angioplasty 18 cases, re-bypass surgery in 13 cases, and lumbar sympathectomy in 4 cases. The results of reoperation were 15 cases of functional recovery, 7 cases of limb salvage, 5 cases of above-knee amputation. 3 cases of below-knee amputation and 3 deaths. Conclusion: The main cause of occlusive complications are occlusion of inflow or outflow artery. Treatments were different according to the first operation methods and graft used. The most frequent time of reoperation was within one year after the first operation. We believe that graft surveillance especially during the first year is very important factor in observing the patient. We can look forward to improving limb salvage rate to perform additional treatment such as radiological interventions and lumbar sympathectomy.

• Korean Journal of Environmental Agriculture
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• v.27 no.2
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• pp.150-155
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• 2008

This study was carried out to determinate the location and the number of air inlet and outlet, optimum air inlet velocity for effective ventilation in windowless weaning piglet house($2.90(W){\times}9.90(L){\times}2.80(H)$ m) by CFD(Computation Fluid Dynamics) simulation. The weaning piglet house for this experiment was consisted of 11 air inlets and 9 outlets, modified and simulated using CFD code, FLUENT. The simulation result for the original weaning piglet house, which was not modified, showed ununiform ventilation for each room. Therefore, for uniform ventilation, 4 air inlets and 1 outlet were completely closed, and 2 air outlets were partially closed. The simulation result for the modified weaning piglet house showed uniform ventilation for each room and the optimum air inlet velocity of 0.5 $m\;sec^{-1}$.

• Korean Journal of Ecology and Environment
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• v.46 no.4
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• pp.524-540
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• 2013

After the construction of the Geum River estuary dam, we investigated the ecological property of phytoplankton community with physicochemical property in 9 stations of Geum River estuary 4 times seasonally in 2010 about the environmental changes through the change of phytoplankton. Physicochemical property seems to show eutrophication which developed from the tendency of accruing of the nutrients (those involved in intermittency of freshwater which flows from the dike and the surrounding cities), caused by the changing of tidal flow, the decreasing of the inflow of seawater after the construction of the Geum River estuary dam (dike). A total of 233 species of species composition of phytoplankton emerged, showing a highly increased result compared to that of the former research. The reason for the increase in number is considered as a phenomenon resulting from the mix of blackish and freshwater marine species in the flow of intermittency of freshwater discharge. Also, the standing crops of phytoplankton considerably increased compared to when the dike had not yet been built. Highly affected by the discharge of occasional freshwater, the diatoms of blackish water zone dominated in spring and winter, while freshwater species appeared to dominate in summer and autumn. The species diversity showed over 2.0 except in winter season. After a cluster analysis, the result showed that the Geum River estuary was influenced by runoff from cities like Gunsan, the sewage which flows from Gyeongpo River, and the intermittency of freshwater discharge from the Geum River estuary dam.