• Journal of the Korean Recycled Construction Resources Institute
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• v.9 no.1
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• pp.1-12
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• 2021

The present study proposes the modified-stoichiometric model for describing hydration of sodium silicate-based alkaliactivated slag(AAS), and compares the results with the thermodynamic modelling-based calculations. The proposed model is based on Chen and Brouwers(2007a) model with updated database as reported in recent studies. In addition, the calculated results for AAS are compared to those for hydrated portland cement. The maximum difference between the proposed model and the thermodynamic calculation for AAS was at most 20%, and the effects of water-to-binder ratio and activator dosages were identically described by both approaches. In particular, the amount of non-evaporable water was within 10% difference, and was in excellent agreement with the experimental results. Nevertheless, notable deviation was observed for the chemical shrinkage, which is largely dependent on the volume of hydrates and pores.

• Journal of Korea Water Resources Association
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• v.56 no.9
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• pp.587-602
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• 2023

Due to climate change, population growth, and economic development, the demand for water in the urban water system (UWS) and the energy required for water use constantly increase. Therefore, beyond the traditional method of considering only the water sector, the Nexus approach, which considers synergies and trade-offs between the water and energy sectors, has begun to draw attention. In previous researches, the Nexus methodology was used to demonstrate that the UWS is an energy-intensive system, analyze the water-energy efficiency relationship surrogated by energy intensity, and identify climate (long-term climate change, drought, type), geographic characteristics (topography, flat ratio, location), system characteristics (total supply water amount, population density, pipeline length), and operational management level (water network pressure, leakage rate, water saving) effects on the UWS. Through this, it was possible to suggest the direction of policies and institutions to UWS managers. However, there was a limit to establishing and implementing specific action plans. This study built the energy intensity matrix of the UWS, quantified the impact of city conditions, external influences, and operational management levels on the UWS using the water-energy Nexus model, and introduced water-energy efficiency criteria. With this, UWS managers will be able to derive strategies and action plans for efficient operation management of the UWS and evaluate suitability and validity after implementation.

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.529-539
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• 1997

The circulations and movement of suspended materials by tidal residual current and seasonal surface wind in the Yellow Sea and the East China Sea are investigated by using a 2-dimensional barotropic model and a particle tracing technique. The tidal residual current is relatively strong around the south and west coast of Korea including the Cheju Island and southern coast of China. The current has a maximum speed of 10 cm/s in the vicinity of Cheju Island with a clockwise circulation. General tendency of the current, however, is to flow eastward along the southern coast of Korea. At the east coast of China from Shanghai to Tunghai, it also shows a eastward flow toward the South Sea of Korea. The anticyclonic circulation formed by wind-driven current and southward current prevails along the coast of Korea in the winter season(from October to April) when northerly wind is dominant. In summer(represented by July), however, the cyclonic circulation appears due to the influence of southerly wind. Suspended materials are advected by tidal residual current and wind-driven current. The long period(ten days) displacement by wind-driven current is bigger than that by tidal residual current. However, the tidal residual current would have the more important role for the advection of the suspended material considering longer period more than several months.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.37-37
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• 2020

일반적으로 생활용수 및 공업용수의 경우 대부분 주수원으로 댐 및 저수지 등을 통해 용수공급이 이루어지며, 일부 지역에서는 하천에서 직접 취수가 이루어지고 있다. 그러나 하천을 수원으로 사용하고 있는 대부분의 지점에서는 계측이 이루어지고 있지 않아 정확한 양을 파악하기 어려운 실정이다. 이러한 현상이 지속 될 경우, 하천 관리를 위한 정확한 가용수량 파악을 통한 수자원 계획 수립 및 수문학적 가뭄정보 생산시 어려움이 수반된다. 수문학적 가뭄 정보를 보다 정확하게 제공하기 위해서는 유역 내 물순환체계 구축, 수문기상 빅데이터 활용, 정확한 유역유출모델링 등 다양한 요소들이 통합적으로 연계되는 것이 무엇보다도 중요하다. 더불어 유역 내 전반적인 물수급 체계를 조사 및 분석하고, 이를 기반으로 모델을 구축하는 것이 선결되어야 할 것으로 판단된다. 이러한 점에서 본 연구에서는 실적기반 가뭄 모니터링을 위한 시공간적으로 상세화 된 물순환 모형을 개발하는데 목적이 있으며, 이를 통해 준실시간으로 하천을 중심으로 가뭄 모니터링이 필요한 지점에 유량을 제공할 수 있는 체계를 개발하고자 한다. 즉, 가뭄에 대해 선제적으로 대응하기 위해서 모니터링 현황, 분석 및 전망 그리고 가뭄 발생지역을 보다 신뢰성 있게 판단하기 위한 가뭄정보 기술정보 제공이 가능한 모형이라 할 수 있다. 이를 통해 궁극적으로 댐, 저수지, 하천 등 다양한 수원을 가지는 유역 내 가용수자원량을 보다 정확하게 판단하여, 다양한 수자원 계획 수립시 기초자료로 활용 될 수 있을 것으로 기대된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3275-3284
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• 2012

This study analyzed a 3D hydrodynamic advection diffusion using the EFDC model (Environmental Fluid Dynamics Code) in the agriculture lake to prevent stratification when we install a water circulator. EFDC model was predicted the range of the water circulator and various operational parameters ware derived for minimize the impact of the internal lake. Through EFDC simulation, water circulation is started overall circulation after 30days and a lake overall circulation showed that it was possible operated the water circulator after about 100days. Also, advection diffusion concentration was low in a lake when water circulator operate intermittent condition than continuous condition. And the entire circulation was stable in this condition. The S/B (Surface/Bottom) ratio can reduce the impact of lake as the surface water mixing a lot of. When the same condition (S/B ratio(3:1)), Case 8 (50days operation: 50days stop) of condition were able to minimize the impact of lake.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2014.06a
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• pp.175-177
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• 2014

본 연구는 부산항에서 차지하는 환적물동량의 위상을 고려하여 환적화물에 대한 정확한 예측을 위한 모델을 수립하는데 그 목적이 있다. 환적물량을 결정짓는 요소로는 부산항의 경쟁력 뿐 아니라 중국 등의 수출입 물동량 증가량과 중국항만의 경쟁력도 중요요소이며, 이들 요소들이 상호간에 영향을 주고 받음에 따라 그러한 순환적 인과관계 분석에 적합한 시스템 다이내믹스(SD) 기법을 활용하여 환적화물에 대한 예측을 시도해 보고자 한다.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.930-930
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• 2012

최근 기후변화로 인하여 전 세계적으로 물 부족현상이 대두되고 있는 가운데 우리나라 또한 물 부족국가에 편재되어 있다. 더군다나 제주도는 최대 다우지임에도 불구하고 다른 타 지역과 마찬가지로 제주도 곳곳에서 물 부족 현상이 야기되고 있다. 이러한 현상은 제주도의 강우가 대부분 년 중 6월~9월에 집중되고, 그 기간 홍수유출 역시 경사가 급하고 15km 미만의 짧은 유로연장을 갖는 대부분의 하천의 특성상 홍수유출 지속시간이 단 시간에 불과하여 수자원 관리에 큰 어려움이 있기 때문으로 사료된다. 다만 일부하천의 경우 해안과 가까운 지점의 하상과 측벽에서 기저유출 성분인 용천수가 유출됨으로 1970년대부터 상수원으로 개발하여 일부분 이용되고 있다. 하지만 이 또한 정확한 용출량 산정이 어려워 수자원으로써의 활용이 미흡한 실정이다. 따라서 본 연구에서는 대상유역의 기저유출로 발생되는 용천수의 용출량을 산정하여 용천수의 이용 및 보전관리계획을 수립하는 중요한 척도를 제시함은 물론 제주 수자원의 대부분을 차지하는 지하수의 함양, 배출, 순환연구에 중요한 기초자료로 활용하기 위하여 진행되었다. 본 연구는 제주도 중서귀수역 주요 기저유출유역(강정천, 악근천)에 대하여 연구대상기간(2011.7~2011.12) 동안 하천의 유출량을 ADCP(Accoustic Doppler Current Profiler, SonTek사)와 전자기식 유속계(FLOW-MATE)를 이용하여 매월 2회 현장 계측을 실시하여 유출량 자료를 확보하였고, 일 단위의 모의가 가능한 유역단위의 준 분포형 장기 강우-유출 모델(continuous rainfall-runoff model)인 SWAT(Soil Water & Assessment Tool) 모델을 적용한 물수지 결과값과 비교 검정하여 제주도 기저유출 하천의 유출율 및 수문곡선의 특성을 분석하고 SWAT 모델을 통한 물수지 산정을 실시하였다. 중서귀수역의 기저유출 대상유역에 대한 지속적인 관측자료와 세계적인 SWAT모델을 이용한 정밀 수자원 해석결과는 서귀포시의 주 식수원으로 이용되고 있는 대상유역의 물순환 및 물수지분석과 통합 수자원의 연구진행, 향후 기후변화에 대비한 효율적인 수자원의 이용 및 확보를 위한 귀중한 자료로 이용될 수 있을 것으로 사료된다.

• Journal of Korean Society of Forest Science
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• v.89 no.5
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• pp.564-575
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• 2000

This study was carried out to reveal characteristics of long-term runoff by using HYCYMODEL in a small forested watershed. From May to September in 1998 and in 1999, the fitness of HYCYMODEL and runoff characteristics were estimated by HYCYMODEL using rainfall and discharge at the experimental watershed. The function of stage and discharge in the experimental watershed was determined as following equation $Q=11.148H^{2.5867}$($R^2=0.9956$). From May to September in 1998 and in 1999, the runoff rates were 57.7% in 1998 and 87.1% in 1999 at the experimental watershed. The discharge was assumed to be increased because of rainfall intensity difference and thinning. By applicability test, the HYCYMODEL showed good estimation of runoff by optimized fifteen parameters. Comparing runoff characteristics before and after thinning by calculating through HYCYMODEL, direct runoff and base runoff increased 4%, 7%, respectively as evapotranspiration decreased 11%. Parameters $D_{50}$ and $K_h$, which were related to the direct run, and a parameter $K_u$, which was related to the baseflow, were assumed to indicate that forest was changed by the effect of thinning and weathering process of bed rock.

• Journal of the Korean Recycled Construction Resources Institute
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• v.10 no.3
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• pp.261-268
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• 2022

In this study, Long-term test specimens were tested in the outdoor exposure environment and the carbonation properies of concrete were analyzed. The test specimens were manufactured in 40 %, 50 % and 60 % according to the w/c ratio. Carbonation was measured at 3 years and 15 years of age. Based on the results, long-term carbonation prediction models(KICT model) were derived. As a result, carbonation increased according to the w/c. Based on the w/c 40 %, w/c 50 % increased about 1.8 times and w/c 60 % increased about 3.7 times. Comparison of carbonation according to age was that the carbonation at 15^th year was about 3 times higher that of 3^rd year. As results of comparing the KICT models and other carbonation prediction models, the carbonation prediction showed different values.

• 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.