• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1972-1975
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• 2008

우리 인간이 수원으로 가장 많이 이용하는 지표수의 이동 및 저장 역할을 하는 호소는 자연환경과 인간을 이어주는 중요한 매개체임은 분명하다. 그러나 최근에 경제 성장만을 위주로 발전을 추구해온 결과, 급격한 산업화에 따른 도시지역으로의 인구 집중 현상은 호소에 자연적 혹은 인위적으로 큰 영향을 주고 있다. 하천의 자정능력을 초과하여 발생하는 오염물질이 신갈 저수지로 유입되어 생태계를 파괴하고, 하천의 최종 유입지인 호소의 오염을 가중시켰다. 경기도 용인시, 화성군, 오산시 지역의 농 공업용수의 공급원으로 이용되고 있는 신갈 저수지로 유입하는 하천 역시 도시로의 인구 집중으로 인한 막대한 생활하수와 주변 지역에 조성된 공장에서 발생하는 사업장 배수의 유입으로 인해 심각하게 오염되어 신갈 저수지의 오염을 가중시키고 있다. 현재 용인시에서는 기흥 호수공원을 2010년까지 신갈 저수지 일대 118만평에 여가와 문화, 휴양시설이 연계된 대규모 유원지로 조성한다는 계획을 가지고 있다. 이에 본 연구에서는 신갈 저수지의 퇴적물 오염도를 조사하여 호수공원 조성 시 기초 데이터의 확충 및 현황파악을 위하여 신갈 저수지의 퇴적물에 대한 모니터링을 실시하였다. 측정 시기는 1차(2007년 7월)와 2차(2007년 10월)로 총 2회 실시하였으며, 조사 지점선정은 수역 전체의 특성을 가장 대표할 수 있는 지점(호심 또는 가장 깊은 곳 등), 주요 유입하천수가 유입된 후 충분히 혼합되는 지점, 호수가 유출되는 지점, 폐수나 하수의 유입으로 항상 오염이 인정되는 지점을 고려하여 신갈저수지의 6지점을 선정하여 조사하였다. 퇴적물 분석항목 중 VS, COD, T-N, T-P, 중금속 농도를 중심으로 신갈 저수지의 퇴적물 오염도를 조사하였다. 각 지점별 1차 퇴적물 조사 결과, VS $23.1{\sim}46.6\;g/kg$, COD $8.5{\sim}26.4\;mg/g$, T-N $0.35{\sim}1.52\;mg/g$, T-P $0.60{\sim}1.05\;mg/g$ 등의 농도로 조사되었으며, 중금속은 수은, 시안, 카드뮴은 검출되지 않았고 구리의 농도는 $0.1{\sim}0.6\;mg/kg$, 납의 농도는 $2.1{\sim}3.5\;mg/kg$로 조사되었다. 또한 각 지점별 2차 퇴적물 조사 결과, VS $22.8{\sim}41.4\;g/kg$, COD $7.9{\sim}21.5\;mg/g$, T-N $0.31{\sim}1.44\;mg/g$, T-P $0.82{\sim}1.01\;mg/g$ 등의 농도로 조사되었으며, 중금속은 수은, 시안, 카드뮴은 검출되지 않았고 구리의 농도는 $0.2{\sim}0.7\;mg/kg$, 납의 농도는 $2.4{\sim}3.8\;mg/kg$로 조사되었다. 본 연구의 조사 결과는 앞으로 호수공원이 조성되는 신갈 저수지를 효율적으로 관리함에 있어 중요한 근거자료가 될 수 있을 것으로 판단된다.

• Journal of the Korean Institute of Gas
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• v.2 no.1
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• pp.99-106
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• 1998

In order to investigate the impact properties of structural materials for LNG tank, instrumented Charpy impact tests were carried out at cryogenic temperatures. $9\%$ Ni steel showed a superior fracture resistance because of less degradation in toughness until 77 K. From the load-deflection curve obtained by an instrumented methods it was found that with the decrease of temperature from 173 K to 77 K, the peak load in the curve increased, but the total absorbed energy decreased. In addition, the energy absorbed during the crack growth was larger than one absorbed in the process of crack initiation. In SUS304L material, the energy absorbed in the process of the crack initiation was relatively large, but the energy absorbed in the process of crack growth was small, the behavior of absorbed energy was well agreed with the observations of the fracture surface which showed a relatively smooth fracture surface. The absorbed Charpy impact energy in the case of A5083 alloy was lower as compared with other steels, and some cracks were observed along the crack propagation direction at the fracture surface of 77 K.

• Land and Housing Review
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• v.2 no.2
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• pp.163-170
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• 2011

Individual Vacuum Pressure Method (IVPM) is a soft ground improvement technique, in which a vacuum pressure can be directly applied to the vertical drain board to promote consolidation and to strengthen the soft ground. This method does not require surcharge loads, different to embankment or pre-loading method. In this study, the ground improvement efficiency of Individual Vacuum Pressure Method was estimated when suction pressure increases step by step(-20, -40, -60, -80kPa) with different periods. During Individual Vacuum Pressure Method process, surface settlement and pore pressure were monitored, and cone resistance as well as water content were also measured after the completion of Individual Vacuum Pressure Method treatment. From the results, optimum duration of each step of vacuum pressure was determined, and the settlement was calculated using FEM numerical analysis.

• Journal of the Korean Society for Railway
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• v.19 no.1
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• pp.20-28
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• 2016

Curved squeal noise may result when railway vehicles run on curved tracks. Contact between the wheels and the rails causes a stick-slip phenomenon, which generates squeal noise. In order to identify the mechanism of the squeal noise systematically, a scaled test rig has been fabricated. Knowledge of the contact forces between the wheels and the rail rollers is essential for investigating the squeal noise characteristics; however, it is difficult to measure there contact force. In this study, contact forces have been calculated indirectly according to the modal behavior of the subframe that supports the rail roller and the responses at specific positions of that subframe. In order to verify the estimated contact forces, the displacements at the contact points between the wheels and rail rollers have been calculated from the estimated forces; the resulting values have been compared with the measured displacement values. The SPL at the specific location has been calculated using the estimated contact forces and this also has been compared with the SPL, measured in a semi-anechoic chamber. The comparisons in displacements and SPLs show good correlation.

• Journal of Korean Society of Environmental Engineers
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• v.34 no.6
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• pp.373-381
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• 2012

An automatic flow and water quality monitoring system was applied to estimate pollutant loads to an urban stream during storm events in DTV (Daeduk Techno Valley), Daejeon, Korea. The monitoring system consists of rainfall gage, ultrasonic water level meter, water quality sensors for DO, temperature, pH, conductivity, turbidity and automatic water sampler for further laboratory analysis. All data are transmitted through on-line system and the monitoring system is designed to be controlled manually in the field and remotely from laboratory computer. Flow rates were verified with field measurements during storm events and showed good agreements. Automatic sampler was used to collect real time samples and analyzed for BOD, COD, TN, TP, SS and other pollutant concentrations in the laboratory. SWMM (Storm Water Management Model) urban watershed model was applied and calibrated using the observed flow and water quality data for the study area. While flow modeling results showed good agreement for all events, water quality modeling results showed variable levels of agreement. These results indicate that current options in the SWMM model to predict pollutant build up and wash-off effects are not sufficient to satisfy modeling of all the rainfall events under study and thus need further modification. This study showed the automatic monitoring system can be used to provide data to assist further refinement of modeling accuracy. This automatic stormwater monitoring and modeling system can be used to develop basin scale water quality management strategies of urban streams in storm events.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.1 no.1
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• pp.41-51
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• 2002

As Advanced Traveler Information System(ATIS) is the kernel of the Intelligent Transportation System, it is very important how to manage data from traffic information collectors on a road and have at borough grip of the travel time's change quickly and exactly for doing its part. Link travel time can be obtained by two method. One is measured by area detection systems and the other is estimated by point detection systems. Measured travel time by area detection systems has the limitation for real time information because it Is calculated by the probe which has already passed through the link. Estimated travel time by point detection systems is calculated by the data on the same time of each. section, this is, it use the characteristic of the various cars of each section to estimate travel time. For this reason, it has the difference with real travel time. In this study, Artificial Neural Networks is used for estimating link travel time concerned about the relationship with vehicle detector data and link travel time. The method of estimating link travel time are classified according to the kind of input data and the Absolute value of error between the estimated and the real are distributed within 5$\~$15minute over 90 percent with the result of testing the method using the vehicle detector data and AVI data of Namsan Tunnel $\#$1. It also reduces Time lag of the information offered time and draws late delay generation and dissolution.

• Journal of the Korean Institute of Landscape Architecture
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• v.43 no.4
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• pp.98-111
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• 2015

Urban environmental problems such as flooding, depletion of ground water, pollution of urban streams and the heat island effect caused by urban development and climate change can be mitigated by the improvement of the urban water cycle. For the effective planning of water cycle management it is necessary to establish aerial Hydrotope Maps, with which we can estimate the status and change of the water allowance for any site. The structure of the German water balance model BAGLUVA, which is based on soil and vegetation, was analyzed and the input data and boundary condition of the model was compared with Korean data and research results. The BAGLUVA Model consists of 5 Input categories (climate, land use, topography, soil hydrology and irrigation). The structure and interconnection of these categories are analyzed and new concepts and implementation methods of topographic factor, maximum evapotranspiration ratio, effective rooting depth and Bagrov n parameter was compared and analyzed. The relation of real evapotranspiration ($ET_a$)-maximum evapotranspiration ($ET_{max}$) - precipitation (P) was via Bagrov n factor represented. The aerial and land use oriented Hydrotope Map can help us to investigate the water balance of small catchment areas and to set goals for volume of rainwater management and LID facilities effectively in the city. Further, this map is a useful tool for implementing water resource management within landscape and urban planning.

• Journal of Korean Society of Environmental Engineers
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• v.33 no.1
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• pp.9-15
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• 2011

The first objective of this study was to investigate water pollution status of Meejae Reservoir, Kunsan, irregularly receiving river water for agricultural and recreational purposes. The second objective of the study was to compare nutrient pollution loads of three nutrient sources: sediment leaching, non-point sources and the receiving water. Water analysis results showed that eutrophication was a concern especially in summer and the calculated TSI (secchi depth), TSI (chlorophyll-a), and TSI (TP) were 53.6, 57.7 and 56.7, respectively. Although there was no significant difference in seasonal mean values of sediment T-N, sediment T-P and sediment organic content, mean differences were found for sampling points. However, T-N and T-P sediment release flux showed seasonal mean differences, while showing no mean difference for sampling points. Water T-N data proportionally correlated with sediment T-N and sediment organic content data, while no statistical correlation was found for water T-P data. Comparison of nutrient loads calculated from three sources showed that the highest T-N load was occurred from the receiving (pumped) water while T-P loads of the receiving water and sediment release flux were similar. The first solution would be considered for the receiving water to improve the water quality of Meejae Reservoir. Reduction of nutrient flux from the sediment would be then tried as the second alternative solution.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.608-608
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• 2012

현재 기후변화의 기상변동성이 커짐에 따라 태풍 및 집중호우 등의 이상기후 현상이 전 지구상에 걸쳐 광역적으로 나타나고 있다. IPCC에서는 이러한 기후변화가 기온 상승에 따른 증발산량의 증가, 강수량 및 유출량의 시공간적 분포의 변동 등을 초래하여 수자원의 효율적 관리 및 안정적인 공급에 어려움을 증대시킬 것으로 전망하였다. 뿐만 아니라 현재 국내 전반에 걸쳐 4대강 사업이 진행되고 있고, 낙동강에서도 낙동강 살리기 사업이 실시되어 주변 지형들의 변화가 진행되고 있다. 이러한 지형의 변화는 현재까지 구축되어 있는 기존자료의 대폭적인 변화를 의미하므로 홍수관련 연구결과에도 변화를 의미하고 있다. 이에 따라 4대강 사업 이후의 기후 변화에 따른 낙동강유역에서의 유출량의 증가를 분석하여 극한홍수의 발생가능성을 제시하고 이러한 극한홍수발생에 따른 위험지역도 과거에 의해 변경될 것으로 판단되어 국내외적으로 하천의 수리검토에 널리 사용되고 있는 1차원 수리해석 프로그램인 FLDWAV를 이용하여 취약지점을 분석하고 위험도를 분석하고자 한다. 낙동강 살리기 사업으로 낙동강에 건설된 8개의 보를 고려한 본류 및 지류에서의 제내지 및 제외지 지형데이터를 구축하고 구축된 자료을 이용해 낙동강 본류 및 지류에 대해서 극한홍수시 200년 빈도, 500년 빈도 홍수량 및 홍수위를 FLDWAV를 통해 정상류로 계산해서 예측하고 500년 빈도 홍수량과 홍수위를 부정류로 계산하여 제방고와 홍수위를 비교하여 범람위험지역을 선정하였다. 그리고 그 결과를 통해 GIS를 통하여 범람위험지역 제내지의 주요도심 구간 포함, 범람 범위를 분석함과 동시에 극한홍수에 따른 도심구간, 비도시구간 등의 범람범위를 분석하였다. 또한 선정한 범람위험지역의 범람 피해규모를 산정하고 피해범위의 현황을 파악하였다. 연구의 결과는 다음과 같이 나타났다. 500년 빈도 홍수시 범람위험지역은 낙동강 본류의 하류부에서 각각 154.7km, 123.2km, 12.9km에 위치한 지점이 선정되었으며 각 지점의 피해규모는 제내지에 범람된 유출량의 수위는 각각 21.7m, 24.3m, 2.11m로 계산되었고 이때의 피해면적은 각각 $2.68km^2$, $2.64km^2$, $1.25km^2$로 나타났다. 이 결과는 기후변화로 인한 극한홍수 발생 가능성과 취약지점의 분석을 통한 지역의 홍수피해 저감과 정책개발에 기본 자료로 활용될 것이며 낙동강 살리기 사업으로 인한 하천주변 지형의 변화를 제공함으로서 앞으로 진행될 연구의 기본 자료로서 이용가능 할 것으로 판단된다. 또한 이전의 홍수방어계획을 개선한 새로운 홍수방어계획의 수립을 통하여 향후 발생될 홍수의 예방 및 대응방안 수립의 참고자료로 이용될 것이며 제내지 및 제외지의 공간확보 연구를 통해 해당 지자체의 토지매수계획의 참고자료로 이용 가능할 것으로 기대된다.

• Korean Journal of Remote Sensing
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• v.35 no.5_2
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• pp.809-818
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• 2019

The Republic of Korea is very vulnerable to damage from storm and flood due to the rainfall phenomenon in summer and the topography of the narrow peninsula. The damage is recently getting worse because of the concentration rainfall. The accurate damage information production and analysis is required to prepare for future disaster. In this study, we analyzed the water surface area changes of Byeokjeong, Sajeom, Subu and Boryeong using Sentinel-1 satellite imagery. The surface area of the Sentinel-1 satellite, taken from May 2015 to August 2019, was preprocessed using RTC and image binarization using Otsu. The water surface area of reservoir was compared with the storage capacity from WAMIS and RIMS. As a result, Subu and Boryeong showed strong correlations of 0.850 and 0.941, respectively, and Byeokjeong and Sajeom showed the normal correlation of 0.651 and 0.657. Thus, SAR satellite imagery can be used to objective data as disaster management.