• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3D
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• pp.407-415
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• 2008

This study presents the methodology to link with aerial photos for advancing the accuracy of topographic survey data that is used to calculate water volume in urban stream. First, GIS spatial interpolation technique as Inverse Distance Weight (IDW) and Kriging was applied to construct the terrain morphology to the sand-bar and grass area using cross-sectional survey data, and also validation point data was used to estimate the accuracy of created topographic data. As the result of comparison, IDW ($d^{-2}_{ij}$, 2nd square number) in Sand-bar area and Kriging Spherical model in grass area showed more efficient results in the construction of topographic data of river boundary. But the differences among interpolation methods are very slight. Image classification method, Minimum Distance Method (MDM) was applied to extract sand-bar and grass area that are located to river boundary efficiently and the elevation value of extracted layers was allocated to the water level point value. Water volume with topographic data from aerial photos shows the advanced accuracy of 13% (in sand-bar) and 12% (in grass) compared to the water volume of original terrain data. Therefore, terrain analysis method in river linking with aerial photos is efficient to the monitoring about sand-bar and grass area that are located in the downstream of Dam in flooding season, and also it can be applied to calculate water volume efficiently.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.3B
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• pp.261-270
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• 2008

Even though there is a great deal of progress in a numerical method of high caliber like SPH, it is very rarely deployed in a water resources community. Despite the great stride in computing environment, depth averaged approach like a nonlinear shallow equation is still efficient tool for flood routing in large watershed, but it can give some misleading information like the inundation height of flood. In this rationale, we numerically simulate the flow into the dry channel, dry channel with an obstacle triggered by the collapse of a two dimensional water column using SPH (Smoothed Particle Hydrodynamics) in order to boost the application of numerical method of high caliber like SPH in a water resources community. As a most severe test of the robustness of SPH, we also carry out the simulation of the flow through a clearance into the wet channel driven by the rapid removal of a water gate. As a hydrodynamic model, we used the Navier-Stokes equation, a numerical integration of which was carried out using SPH. To verify the validity of newly proposed numerical model, we compare the numerically simulated flow with the others in the literature mainly from VOF and MAC, and hydraulic experiments by Martin and Moyce (1952), Koshizuka et al. (1995) and Janosi et al. (2004). It was shown that agreements between the numerical results in this study and hydraulic experiments are remarkable.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.379-385
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• 2023

EDue to climate change and urbanization, the localized heavy rainfall frequently exceeded a design storm rainfall and flood damage has occurred in South Korea. The concept of addressing sustainable river management and environmental and social issues through Nature-based Solutions (NbS) is gaining attention as it seeks to resolve these issues through ecosystem services. Therefore, in this study, the flood reduction effect by river management using NbS was quantitatively analyzed for the Hwang River, which is directly downstream of Hapcheon Dam, South Korea. Floodplain excavation and dyke relocation, which are methods of the NbS, were applied to the flood risk area of the Hwang River. As a result of analyzing the flood level of the river through the unsteady flow analysis of HEC-RAS, we obtained flood level reduction by 8 cm at the confluence of the Nakdong River. The results of this study can be expected to be sufficiently utilized as a basis for use as a management plan through NbS rather than the river management with grey infrastructure.

• The Journal of the Convergence on Culture Technology
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• v.10 no.5
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• pp.693-698
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• 2024

As there are various types of discontinuities developing along with various rock types, the orientation and density of each type of discontinuities were measured to analyze the behavior of groundwater within the rock mass. Among the orientations of discontinuities, the strike was measured in azimuth and expressed as a discontinuity trajectory, and the density of discontinuities was quantified as the sum of the lengths of discontinuities developed per unit area. The overall discontinuity trajectory in the study area is predominantly in the northeast direction, the north-south and east-west directions are dominant in the igneous rock distribution area, and the east-west and northeast directions are dominant in the sedimentary rock distribution area. Among the types of discontinuities, they show discontinuity trajectories similar to the northeast direction, which is the dominant orientation of stratum boundaries, stratification, and foliation. The discontinuity density ranges from 0.1 m^-1 to 1,000 m^-1. The density distribution of discontinuities was expressed in the form of discontinuity contour diagrams. As a result, the crushed rock near Demiseam in the southern and southwestern part of the study area, the igneous rock area around Maryeong-myeon, the igneous rock area near Yongdam Dam in the northeast, and the igneous rock area near Unilam and Banilam in the northwest showed the highest density of discontinuities at over 100m^-1., the sedimentary rock area near Maisan Mountain showed relatively low values. It suggests that the results of geophysical exploration and drilling survey data in the existing study area, as well as the geological structure and density and trajectory of discontinuities, may be important factors in the behavior of groundwater in rock mass in the future.

• Journal of the Korean Geotechnical Society
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• v.25 no.12
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• pp.87-105
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• 2009

Nonlinear dynamic deformation characteristics, expressed in terms of normalized shear modulus reduction curve (G/$G_{max}-\log\gamma$, G/$G_{max}$ curve) and damping curve (D-$\log\gamma$), are important input parameters with shear wave velocity profile ($V_s$-profile) in the seismic analysis of (new or existing) fill dam. In this paper, the reasonable and economical methods to evaluate the nonlinear dynamic deformation characteristics for core zone and rockfill zone respectively are presented. For the core zone, 111 G/$G_{max}$ curves and 98 damping curves which meet the requirements of core material were compiled and representative curves and ranges were proposed for the three ranges of confining pressure (0~100 kPa, 100 kPa~200 kPa, more than 200 kPa). The reliability of the proposed curves for the core zone were verified by comparing with the resonant column test results of two kinds of core materials. For the rockfill zone, 135 G/$G_{max}$ curves and 65 damping curves were compiled from the test results of gravelly materials using large scale testing equipments. The representative curves and ranges for G/$G_{max}$ were proposed for the three ranges of confining pressure (0~50 kPa, 50 kPa~100 kPa, more than 100 kPa) and those for damping were proposed independently of confining pressure. The reliability of the proposed curves for the rockfill zone were verified by comparing with the large scale triaxial test results of rockfill materials in the B-dam which is being constructed.

• Economic and Environmental Geology
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• v.37 no.1
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• pp.121-131
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• 2004

Removal efficiencies of soil washing and soil improvement processes to remediate farmland soils and stream deposits around Goro abandoned mine were investigated with batch and column experiments. For As-contaminated farm-land soils around Goro mine, batch tests to quantify As extraction rate from contaminated soils and lime treated contaminated soils were performed. The contaminated soil mixed with lime decreased As extraction rate less than one fourth, suggesting that the soil improvement method mixed with lime dramatically decrease As extraction rate. A storage dam will be constructed in the lower part of the main stream connected to Goro abandoned mine and the amount of As extracted from the bottom soils of reservoir could be the main source to contaminate water of reservoir. The decrease of As extraction amount from the bottom in reservoir, caused by the application of the soil improvement method was investigated from the physically simulated column experiment and results showed that As extraction rate decreased to one forty when 1％ lime mixed soil improvement was applied to contaminated soils. For contaminated stream deposits connected Goro mine, the removal efficiency of the soil washing method was investigated with batch experiments. Hydrochloric acid, citric acid, acetic acid and distilled water were used as soil washing solution and 0.01, 0.05, 0.1, 0.5, 1.0 N of washing solution were applied to extract As. When washing with 0.05 N of hydrochloric acid or citric acid, more than 99.9% of As was removed from stream deposits, suggesting that As contaminated stream deposits around Goro mine be successfully remediated with the soil washing process. Total volumes of contaminated soils and deposits needed for remediation were calculated based on three different reme-diation target concentrations and the operation cost of soil washing for calculated soil volumes was estimated. Results from this research could be directly used to make a comprehensive countermeasure to remediate contaminated area around Goro mine and also many contaminated areas similar to this research area.

• Proceedings of the Korea Water Resources Association Conference
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• 2004.05b
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• pp.1310-1315
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• 2004

용수수요 추정의 기본은 수도계획에 사용할 수 있는 실사용량에 대한 조사로 이에 대한 자료가 거의 없기 때문에 각 수도사업별로 제시되는 추정방법이 조금씩 상이하며, 추정방법의 진위를 가릴 수 없이 수요추정의 악순환을 초래하고 있는 실정이다. 기존 물사용량 예측은 급수량 기준의 도시 전체에 내한 평균 LPCD를 이용함에 따라 물사용 특성을 충분히 고려찬 수 없어 지역별 실제 물사용량과 큰 오차가 유발되었다. 그러므로 수도계획 및 설계에 사용할 수 있는 신뢰성 있는 설계인자를 도출하기가 불가능하여 물수요 관리정책 수립, 수도요금체계 조정 및 누수방지계획 수립 등 경제적인 수도시설의 건설에 애로를 겪고 있다. 본 연구에서는 생활용수 중 가정용수에 대하여 세탁기, 변기, 싱크대 등 수도전에 유량계를 설치 실제 가정에서 사용하고 있는 용도별 사용량을 실측, 파악하였으며, 이로부터 얻은 용도별 사용량에 대한 기간별 소비특성을 분석하였다. 이로부터 생활용수 사용량의 소비패턴 및 시간대별 부하율 산정이 가능하며, 각종 용도별 사용수량의 소비형태를 찾아낼 수 있었다. 또한 가정용수 중 용도별 물 사용비율은 세탁용수, 변기, 주방, 목욕용수의 순으로 나타났으며 주택유형별로는 아파트 연립주택, 다세대 주택, 단독주택의 순으로 단독주택에서의 물사용량이 가장 적게 나타났다. 생활용수 공급량에 내해서는 시간별, 주별, 월별 그리고 계절변동 총량을 파악하였으며 시간대별로는 오후 3시경이 최대 소비량을 보였고, 주별로는 월요일 그리고 월별로는 7월의 용수사용량이 가장 큰 것으로 조사 되었다. 본 연구로부터 도출된 용도별 실측 물사용량 자료 및 분석결과로부터, 지금까지 공급량 기준의 계획수립이 이루어져왔던 파종 수도시설 규모결정시 합리적인 용수수요예측 및 수요관리가 이루어질 수 있을 것으로 판단되며, 용수수요의 과다예측 오해 해소 등 경제적, 과학적 물관리 정책수립을 위한 기초자료를 제공할 수 있을 것으로 기대된다.는 경제적인 방법이 될 수 있다. 하천수 등의 상호 관계 분석을 통해 장기간의 유역 물순환체계 변화를 분석할 수 있었다.골풀과, 닭의장풀과가 각 1종씩으로, 조사지점( I )보다 좀 더 많은 종이 분포하는 것으로 조사되었다. 또한 어류는 조사지점( I )에서 3회에 걸쳐 총 396개체가 채집되어 3목 8과 21종이었다. 이 중 한국 고유종은 11종이었고, 외래 어종은 검정우럭과 2종이 조사되었으며, Zacco platypus(피라미), Zacco temmincki(갈겨니), Acheilongnathus koreanus(칼납자루), Odontobutis platycephala(동사리), Coreoleuciscus splendidus(쉬리) 순으로 분포하고 있었고, Acheilognathus signifer(묵납자루)는 댐 건설 전에는 많이 분포하였으나 현장조사에서 서식을 확인 할 수 언어 개체수의 큰 감소내지 멸종된 것으로 추정되었다.에서 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 수술적 교정을 해줌으로써 좋은 성적을 기대할 수 있음을 보여주었다.특히 교사들이 중요하게 인식하는 해방적 행동에 대한 목표를 강조하여 적용할 필요가 있음을 시사하고 있다.교하여 유의한 차이가 관찰되지 않았다. 또한 HSP 환자군에서도 $IL1RN^{*}2$ allele 빈도와 carriage rat

• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.4
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• pp.81-89
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• 2009

The seepage should be analyzed to design or reinforce the levees. The steady seepage analysis is an usual application in USA and European countries where the large scaled dams and levees are existed. However, Korea and Japan, where the reaching time is short, the excessive forces are applied on the levees at the short reaching time if the seepages are analyzed in steady condition. Accordingly, the unsteady analysis based on the variation of time is necessitated. In the unsteady analysis, the flood wave type is necessary. No criteria and standards, however, are derived for the unsteady seepage in Korea. In the study, the flood wave type is derived for the unsteady seepage. The major reliable flood surface data are collected in 5 stations including Jindong of the Nakdong river basin. The data are sorted in duration, and they are non-dimensionalized. The statistical method is also applied to derive the waves. To verify the study, the seepage is analyzed by the derived wave and applied to the prototype. The results are also compared with the Japanese Method. The errors between the hydraulic gradient and critical velocity method are $0{\sim}0.7%$, $0{\sim}0.7%$ at the Jindong, $1.6{\sim}4.0%$, $1.7{\sim}4.1%$ at the Hyunpoong, $0.6{\sim}3.6%$, $0.6{\sim}3.7%$ at the Waegwan, $2.0{\sim}8.1%$, $2.0{\sim}8.1%$ at the Nakdong, and $1.2{\sim}9.8%$, $1.3{\sim}9.9%$ at the Jeongam, respectively. The relationship($R^2$) between each method is relatively high as $0.983{\sim}0.999$. This means the results are more logical than the Japanese method, and the study is applicable to the design of hydraulic structures.

• Restorative Dentistry and Endodontics
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• v.35 no.6
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• pp.453-460
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• 2010

Objectives: To evaluate the accuracy and consistency of two different apex locators at both the Apex and 0.5 marks. Materials and Methods: Twenty-six root canals was scheduled for extraction for periodontal or prosthodontic reasons. Thirteen canals were measured using Root ZX and the rest by i-ROOT. The root canal length was measured both the at 0.5 mark and the Apex mark. The file was then fixed to the toot, and the distance from the file tip to the major foramen of each canal was measured after removing the root dentin under the microscope so that the major foramen and the file tip were seen. Results: 1. When the Apex mark was used, 100% of both the Root ZX and i-ROOT groups were within 0.5 mm of the major foramen. 2. When 0.5 mark was used, 100% of the Root ZX group and 77% of the i-ROOT group were within 0.5 mm of the major foramen. 3. In terms of standard deviation and quartile value, the Apex mark was more consistent than 0.5 mark in the Root ZX group, and 0.5 mark was more consistent in the i-ROOT group, but there was no statistically significant difference when compared with t-test. 4. The root canal length difference between the Apex mark and 0.5 mark was 0.22 mm and 0.46 mm in the Root ZX and i-ROOT groups, respectively. Conclusions: In this study, the Apex mark was the more consistent mark. Therefore, it is recommended to subtract 0.5 mm, which is the average length between the apex and apical constriction, from the root canal length at the Apex mark to obtain the working length clinically.

• Korean Journal of Soil Science and Fertilizer
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• v.36 no.3
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• pp.163-179
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• 2003

Multifunctionality of agriculture which is not traded on the market now has been an important international issue in that it environmental and public benefits. We carried out to modify and to update the function of upland farming on flood prevention and fostering water resources. Economic values of environmental benefits were evaluated by replacement cost methods. Models to evaluate the function of preventing flood were selected as: (1)precipitation(flood-inducing) - runoff(A), (2) soil depth ${\times}$ soil air phase, (3) precipitation (flood-inducing) - runoff(B), (4) soil depth ${\times}$ effective porosity of soil. Models to estimate the function of fostering water resources were (1) saturated hydraulic conductivity (Ks) ${\times}$ duration of saturation(days) ${\times}$ (1-ratio of water flow directly into river), (2) precipitation ${\times}$ ratio of water fostered by rain resources ${\times}$ (area of upland/total land area), and (3) soil water retention quantity(under standing crop or tree) - SWRQ(in bare soil). Function of preventing flood was $883Mg\;ha^{-1}$ of water per year and 645 million Mg for the whole upland area. Function of fostering water resources was $94.1Mg\;ha^{-1}$ of water per year and 69 million Mg for the whole upland area. The value of flood-preventing function evaluated by replacement cost methods was estimated 1,428 billion won per year as compared to the cost for dam construction. The value of water resource fostering were estimated 8.6 billion won in the price of living water.