• Journal of Korea Water Resources Association
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• v.38 no.7 s.156
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• pp.555-564
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• 2005

In this study, a simple rainfall-runoff model was proposed by using the hydraulic routing model that requires relatively few parameters. The parameters of this model were estimated by the watershed characteristics data, and were applied to the Soyang watershed and Ui stream watershed by using the kinematic wave for overland flow and dynamic wave routing for channel routing. In order to demonstrate validity, the proposed approach was compared to the HEC-1 model for the Soyang watershed. As the results of modeling have shown, the hydraulic model shows reasonable results similar to that of the HEC-1 model. This model also represents good results for the Ui stream watershed. Hence, even if this model is a simple rainfall-runoff model using general methodology, it is competitive to the natural watershed. However, it is still difficult to estimate the roughness coefficient and the catchment width, and therefore this model is in need of such supplements.

• Journal of the Korea Society of Computer and Information
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• v.4 no.2
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• pp.19-26
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• 1999

The geographic information system is needed in the image recognition field. This study recommends an efficient method to construct the GIS from the feature extraction of roads through scanning of a normal or hand-made maps. Many algorithms have been presented for such image information recognition. However, such algorithm processes have limitations due to their complexity. To efficiently extract road information from scanning map images. a $3{\times}3$ directional form is applied - structuring element, erosion and dilation, and opening and closing. This method allows for efficient evaluation of the featured road extracts from the map image and from the character sets.

• Applied Chemistry for Engineering
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• v.30 no.5
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• pp.627-632
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• 2019

In this study, Laminaria japonica was used as a substrate for a mixed aerobic microbial consortium. Laminaria japonica is well-known as a representative brown algal biomass possessing advantages of cheap cost, and high productivity and carbohydrate content. A biological saccharification system was established by inoculating and enriching the mixed aerobic microbial consortium. Production of the soluble carbohydrate and reducing sugar at different hydraulic retention times (HRT) was observed. The efficiency of saccharification increased according to the decrease of HRT. The maximum saccharification yield in a continuous biological pretreatment process was 17.96 and 4.30 g/L/day for the soluble carbohydrate and reducing sugar, respectively at the HRT of 1 day. In contrast, the staccharification yield decreased drastically at the HRT of 0.5 day. Experimental results indicate that Laminaria japonica is a promising material for the production of useful products, in particular for the saccharification through a biorefinery process. It can thus be concluded that a continuous biological pretreatment process using a mixed cultivation system can be successfully employed for the biorefinery technology.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.5
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• pp.294-302
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• 2020

In a genetic algorithm, computer simulations are performed based on the natural evolution process of life, such as selection, crossover, and mutation. The genetic algorithm searches the approximate optimal solution by the parallel arrangement of Schema, which has a short definition length, low order, and high adaptability. This study examined the possibility of improving the efficiency of the optimal solution by considering the characteristics of the building block hypothesis, which are one of the key operating principles of a genetic algorithm. This study evaluated the efficiency of the optimization results according to the gene sequence for the implementation in solving problems. The optimal design problem of the water pipe was selected, and the genetic arrangement order reflected the engineering specificity by dividing into the existing, the network topology-based, and the flowrate-based arrangement. The optimization results with a flowrate-based arrangement were, on average, approximately 2-3% better than the other batches. This means that to increase the efficiency of the actual engineering optimization problem, a methodology that utilizes clear prior knowledge (such as hydraulic properties) to prevent such excellent solution characteristics from disappearing is essential. The proposed method will be considered as a tool to improve the efficiency of large-scale water supply network optimization in the future.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.1
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• pp.67-73
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• 2000

The water quality of inland stream is polluting with industrialization and urbanization, and with that water quality of lake also deteriorated, to manage water quality pollution problem of lake, new water quality management method is needed. As a pilot study of the method that manage water quality of lake using GSIS(Geo-Spatial Information System), we study the method which automatically extract the hydraulic characteristic informations of lake in GSIS environment. Also, as an example of practical use of the extracted hydraulic characteristic information of lake, we carry out the characteristic analysis of waterbody flow using finite different method. With the automation the extraction procedure of hydraulics characteristic information needed in characteristic analysis of waterbody flow, we carried out the analysis efficiently. Particularly, with the extraction of section information on lake not in layout form, in analyzable form, we make the analysis that section information of lake was indispenably required(e.g. stratification analysis) possible in GSIS environment.

• Journal of Wetlands Research
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• v.15 no.1
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• pp.79-90
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• 2013

Stormwater wetland targeted to treat the rainfall runoff from cow feeding-lot basin has been monitored from May 2010 to November 2011. Reduction efficiency estimated based on 20 rainfall event monitoring was 88%, 54%, 70%, 31%, and 64% for TSS, BOD, $COD_{Cr}$, TN, and TP, respectively. Theoretically, as rainfall depth increases, hydraulic exchange ratio has to be increased. When the exchange ratio approaches to 1 (usually design goal), TSS reduction efficiency was estimated about 55%. Uncertainty in reduction efficiency of the stormwater wetland is normally very high due to the continuous rainfall activity, its magnitude and intensity, antecedent dry days, and other natural variables which can not be controlled by experiment conductors. In this study, predominant affecting variables was found to be hydraulics caused by consecutive rainfall events having different intensity and algal growth during dry days.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.1104-1108
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• 2010

최근 수자원의 효율적인 배분을 위한 수자원관리의 중요성에 대한 인식과 하천의 환경적 기능에 대한 사회적 요구 증대로 수자원 기초조사에 의해 수집되어진 자료의 활용빈도가 다양한 분야에서 증가하고, 높은 신뢰도와 정확도를 요구하고 있다. 개발된 수위-유량 관계식의 신뢰도 검증은 일반적으로 지점별 수위-유량 관계식과 수위자료에 의해 산정된 유하량을 유역의 면적평균 강우량을 이용하여 산정한 유출률과 비교 분석하는 수문학적 방법에 의해 이루어지고 있는 실정이다. 최근에는 공간적인 비균질성을 고려하여 유출과정에서 운동역학적인 이론을 기반으로 물의 흐름을 수리학적으로 추적해 나가는 물리적 기반의 분포형 유출모형의 활용도가 높아지고 있음에 따라 본 연구에서는 낙동강수계 임하댐유역을 대상으로 물리적 기반의 분포형 모형인 $Vflo^{TM}$을 적용하여 유출량을 산정하고, K-water에서 수자원 환경기초조사 성과로 개발된 임하댐 상류 영양 수위관측소의 수위-유량 관계 곡선식을 이용하여 산정된 유출량과 비교함으로써 수자원기초조사 성과의 신뢰도를 검증하였다. 분포형 유출모형 적용에 필요한 매개변수 추출을 위해 GIS 기법을 이용하여 DEM, 토지피복도, 토양도에서 $Vflo^{TM}$의 입력인자인 경사도, 흐름방향, 조도계수, 수리전도도, 유효공극률, 토양심도를 추출 산정하였으며, 임하댐 유역의 8개 우량관측소 시우량자료를 이용하여 강우의 공간적인 통계 특성을 잘 반영하는 크리깅(Kriging) 기법에 의한 분포형 강우를 생성하였다. 또한, 본 모형을 통해 검증된 초기함수조건 등의 유역의 특성을 이용한 단기유량예측을 통하여 홍수량 예측 및 수문조사 효율성 향상에 매우 중요한 역할을 할 것으로 기대된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.439-439
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• 2021

하천에서는 물리적 및 생태적 측면에서 종횡적 연결성이 매우 중요하며 이를 통해 물리적 환경 변화에 따라 변화하는 생물의 종도 연속적으로 변화하여 이어진다. 하천에서 안정적으로 물이 흐르고 거기서 서식하는 어류들의 보호 및 생태계 보전을 위해 어류의 이동이 가능하도록 보 혹은 댐 등과 같은 하천 횡단구조물 설계 시 어도를 추가적으로 설치하고 있다. 어도는 어류의 이동이 차단 혹은 곤란한 경우 이동이 가능하도록 만들어진 수로를 의미한다. 국내에 설치된 보는 35,000개 이상으로 이 중 어도는 5,081개가 설치되어 있다. 우리나라의 하천설계기준의 어도설계기준은 2002년에 개정되었으며 보의 부대시설로 어도의 형식에 대해서 다루어졌다. 그러나 어도의 기능을 평가하고 효율성을 증대시키기 위하여 어도 내의 수리 특성을 정확히 파악하여야 하며 또한 어류거동 및 이동에 대한 특성을 고려하여 적절한 어도의 위치선정 및 설계유량을 선정해야한다. 이를 위해 본 연구에서는 2차원 수리해석모형(Kim et al., 2018)에 Lagrangian기반 어류이동모형을 결합한 수치모형을 개발하고 이를 수리실험결과(Tan et al., 2018)와 비교하여 검증을 수행하였다. 어류의 운동 및 생물학적 특성을 반영하기는 매우 어렵기 때문에 현장조사 및 실험실 테스트로 통하여 획득한 주요 특성만을 반영하였다. 이러한 시도는 최근 기후변화 및 하천의 자연성 회복을 위한 종횡적 연결성을 검토하고 어도기능을 평가할 수 있는 기술로 활용이 가능할 것으로 보인다.

• The Journal of Engineering Geology
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• v.27 no.3
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• pp.293-304
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• 2017

This study was performed in order to hydrogeological analysis of aquifer, which is a necessary part for evaluating the efficiency of the combined well and open-closed loops geothermal (CWG) systems. CWG systems have been proposed for the effective utilization of geothermal energy by combining open loop geothermal systems and closed loop geothermal systems. Small aperture CWG systems and large aperture CWG systems were installed at a green house land with water curtain facilities in Chungju City. Aquifer tests include pumping tests and step-drawdown tests were conducted to analyse hydrogeological characteristics of aquifer in the study area. The transmissivity was estimated in the range of $13.49{\sim}58.99cm^2/sec$, and the storativity was estimated in the range of $1.13{\times}10^{-5}{\sim}5.20{\times}10^{-3}$. The geochemical analysis showed $Ca^{2+}$ ion and ${HCO_3}^-$ ion were dominant in groundwater. The Langelier Saturation Index and the Ryznar Stability Index showed low scaling potential of groundwater. In the analysis of vertical water temperature change, the geothermal gradient was estimated as $2.1^{\circ}C/100m$, which indicated the aquifer was enough for geothermal systems. In conclusion, groundwater is rich, can stably use geothermal heat, and it is less likely to cause deterioration of thermal energy efficiency by precipitation of carbonate minerals in study area. Therefore, the study area is suitable for installation of the combined geothermal system.

• Proceedings of the Korea Water Resources Association Conference
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• 2022.05a
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• pp.237-237
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• 2022

우리나라 하천 내에 설치된 횡단구조물은 보 35,000개소 이상으로 전국 하천의 0.6 km마다 수공구조물이 위치해 있으며 이로 인해 종적(longitudinal) 연결성에 영향을 미치는 것으로 나타났다. 농어촌연구원의 조사에 따르면 하천 횡단구조물이 설치된 구간에 어도 설치율은 14.9%로 나타났으며 이는 수생태 관점에서 연속성이 매우 열악한 상태임을 확인 할 수 있다. 이에 우리나라 각 부처 국토교통부, 환경부 등에서는 수생태 연속성을 확보하고자하는 노력이 지속되고 있으며 대표적으로 어류의 이동통로인 어도를 설치하거나 기존 어도의 효율을 향상시키기 위하여 개보수 작업을 지속적으로 실시하고 있다. 어도의 기능을 평가하기 위해서는 어도 내의 수리특성을 정확히 파악하는 것이 중요한데 연속적인 구조물로 구성된 어도 내 흐름은 매우 복잡하다. 특히 어도 내 구조물간 상호작용에 의하여 비정상 흐름이 발생하며 구조물 뒤에서는 사수역(dead zone)이 형성된다. 사수역에서 나타나는 와류의 거동은 구조물의 기하학적 특성에 따라 변화한다. 본 연구에서는 2차원 수심적분 수치모형을 활용하였으며 벽면 근처 점성저층의 유속분포을 재현하기 위하여와 점성항에 감쇠함수(damping function)를 고려하였다. 수치모형의 검증을 위해 실내 실험수로의 직선 개수로에서 PIV(particle image velocimetry)를 활용하여 연속적으로 배치된 구조물에 의한 유속자료를 활용하였다. 이 결과는 향후 새로운 어도설계 혹은 기 설치된 어도의 수리학적 기능을 평가하는데 활용이 가능할 것으로 보인다.