• Journal of The Korean Society of Agricultural Engineers
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• v.58 no.4
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• pp.21-35
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• 2016

This study is to evaluate the applicability of SWAT (Soil and Water Assessment Tool) model for multi-purpose dams and multi-function weirs operation in Namhan river basin ($12,577km^2$) of South Korea. The SWAT was calibrated (2005 ~ 2009) and validated (2010 ~ 2014) considering of 4 multi-purpose dams and 3 multi-function weirs using daily observed dam inflow and storage, evapotranspiration, soil moisture, and groundwater level data. Firstly, the dam inflow was calibrated by the five steps; (step 1) the physical rate between total runoff and evapotranspiration was controlled by ESCO, (step 2) the peak runoff was calibrated by CN, OV_N, and CH_N, (step 3) the baseflow was calibrated by GW_DELAY, (step 4) the recession curve of baseflow was calibrated by ALPHA_BF, (step 5) the flux between lateral flow and return flow was controlled by SOL_AWC and SOL_K, and (step 6) the flux between reevaporation and return flow was controlled by REVAPMN and GW_REVAP. Secondly, for the storage water level calibration, the SWAT emergency and principle spillway were applied for water level from design flood level to restricted water level for dam and from maximum to management water level for weir respectively. Finally, the parameters for evapotranspiration (ESCO), soil water (SOL_AWC) and groundwater level fluctuation (GWQMN, ALPHA_BF) were repeatedly adjusted by trial error method. For the dam inflow, the determination coefficient $R^2$ was above 0.80. The average Nash-Sutcliffe efficiency (NSE) was from 0.59 to 0.88 and the RMSE was from 3.3 mm/day to 8.6 mm/day respectively. For the water balance performance, the PBIAS was between 9.4 and 21.4 %. For the dam storage volume, the $R^2$ was above 0.63 and the PBIAS was between 6.3 and 13.5 % respectively. The average $R^2$ for evapotranspiration and soil moisture at CM (Cheongmicheon) site was 0.72 and 0.78, and the average $R^2$ for groundwater level was 0.59 and 0.60 at 2 YP (Yangpyeong) sites.

• Korean Journal of Remote Sensing
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• v.35 no.6_3
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• pp.1197-1208
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• 2019

Wildfire is a major natural disaster affecting socioeconomics and ecology. Remote sensing data have been widely used to estimate the wildfire danger with an advantage of higher spatial resolution. Among the several wildfire related indices using remote sensing data, Temperature Vegetation Dryness Index (TVDI) assesses wildfire danger based on both Normalized Difference Vegetation Index (NDVI) and Land Surface Temperature (LST). Although TVDI has physical advantages by considering both weather and vegetation condition, previous studies have shown TVDI does not performed well compare to other wildfire related indices over the Korean Peninsula. In this study we have attempted multiple modification to improve TVDI performance over the study region. In-situ measured air temperature was employed to increase accuracy, regression line was generated using monthly data to include seasonal effect, and TVDI was calculated at each province level to consider vegetation type and local climate. The modified TVDI calculation method was evaluated in wildfire cases and showed significant improvement in wildfire danger estimation.

• 한국공간정보시스템학회:학술대회논문집
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• 2005.05a
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• pp.201-205
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• 2005

미국과 일본 등 많은 나라들이 연안역에 대한 오염총량관리제를 실시하고 있으며 우리나라 역시 90년도 초반부터 환경부와 국립환경연구원에 의하여 4대강을 대상으로 내륙에 대한 지자체 단위의 오염총량관리제가 추진되고 있다. 연안해역에서도 최근 해양오염방지법의 개정으로 특별관리해역 지정 등 특정 연안해역에 영향을 미치는 육역을 포함하는 연안역 통합관리제가 해양수산부에 의하여 추진되고 있다 또한 외국의 사례로서 미국 체사피크만에서는 오염총량관리제를 포함하는 연안역 통합관리제 수립 및 운용을 위하여 GIS 및 모델 package로 구성된 시스템을 구축 활용하고 있으며, 이런 GIS 및 모델 package로 구성된 시스템을 바탕으로 연안역 통합관리를 위한 기본적인 자료를 수집 분석하고 정책 수립의 방향을 제시하고 있다. 하지만 우리나라에서는 아직까지 연안역 통합관리를 위한 기초 자료도 많이 부족하고 이런 기초 자료를 토대로한 분석 도구인 GIS-modeling 시스템 개발도 매우 미미한 실정이다. 따라서 본 연구에서는 GIS를 이용하여 오염원의 발생 및 배출부하 산정 과정을 공간적으로 분석하여 환경관리에 응용할 수 있는 방안을 제시하고자 한다. 또한 효율적인 연안의 오염원 관리를 위하여 기존 환경부 및 관련 기환 자료를 활용하여 잠실 수중보에서 한강 하구의 세부 오염원자료를 수집하여 GIS 기반의 오염원데이터베이스를 구축하고, 오염부하산정모델을 개발한 후, 구축된 정보의 효율적인 관리와 분석을 위한 GIS 프로그램을 개발하였다. 아울러 육역에서의 오염물질 배출에 따른 연안역 수질의 모의를 통해 육역과 연안역에 대한 효율적인 통합관리방안을 제시하고자 한다.사용될 수 있는 블루투스 서비스와 서비스 속성을 기술한 XML 문서에서 블루투스 기기에 적합한 내부 정보를 생성하는 생성기를 설계하고 구현을 하였다.보다는 현저히 낮았다. 총 휘발성 유기화합물읜 농도는 실내가 실외 보다 높았다(I/O ratio 2.5). BTEX의 상대적 함량도 실내가 실외보다 높아 실내에도 발생원이 있음을 암시하고 있다. 자료 분석결과 유치원 실내의 벤젠은 실외로부터 유입되고 있었고, 톨루엔, 에틸벤젠, 크실렌은 실외뿐 아니라 실내에서도 발생하고 있었다. 정량한 8개 화합물 각각과 총 휘발성 유기화합물의 스피어만 상관계수는 벤젠을 제외하고는 모두 유의하였다. 이중 톨루엔과 크실렌은 총 휘발성 유기화합물과 좋은 상관성 (톨루엔 0.76, 크실렌, 0.87)을 나타내었다. 이 연구는 톨루엔과 크실렌이 총 휘발성 유기화합물의 좋은 지표를 사용될 있고, 톨루엔, 에틸벤젠, 크실렌 등 많은 휘발성 유기화합물의 발생원은 실외뿐 아니라 실내에도 있음을 나타내고 있다.>10)의 $[^{18}F]F_2$를 얻었다. 결론: $^{18}O(p,n)^{18}F$ 핵반응을 이용하여 친전자성 방사성동위원소 $[^{18}F]F_2$를 생산하였다. 표적 챔버는 알루미늄으로 제작하였으며 본 연구에서 연구된 $[^{18}F]F_2$가스는 친핵성 치환반응으로 방사성동위원소를 도입하기 어려운 다양한 방사성의 약품개발에 유용하게 이용될 수 있을 것이다.었으나 움직임 보정 후 영상을 이용하여 비교한 경우, 결합능 변화가 선조체 영역에서 국한되어 나타나며 그 유의성이 움직임 보정 전에 비하여 낮음을

• Journal of the Korean Association of Geographic Information Studies
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• v.18 no.2
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• pp.1-15
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• 2015

Urban flooding threatens human beings and facilities with chemical and physical hazards since the beginning of human civilization. Recent studies have emphasized the integration of data and models for effective urban flood inundation modeling. However, the model set-up process is tend to be time consuming and to require a high level of data processing skill. Furthermore, in spite of the use of high resolution grid data, inundation depth and velocity are varied with building treatment methods in 2-D inundation model, because undesirable grids are generated and resulted in the reliability decline of the simulation results. Thus, it requires building generalization process or enhancing building orthogonality to minimize the distortion of building before converting building footprint into grid data. This study aims to develop building generalization method for 2-dimensional inundation analysis to enhance the model reliability, and to investigate the effect of building generalization method on urban inundation in terms of geographical engineering and hydraulic engineering. As a result to improve the reliability of 2-dimensional inundation analysis, the building generalization method developed in this study should be adapted using Digital Building Model(DBM) before model implementation in urban area. The proposed building generalization sequence was aggregation-simplification, and the threshold of the each method should be determined by considering spatial characteristics, which should not exceed the summation of building gap average and standard deviation.

• Journal of The Korean Association For Science Education
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• v.34 no.3
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• pp.247-260
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• 2014

Purpose of this study is to analyze the roles and strategies of imagistic simulation observed in mental simulation about problematic situation of prediction, and thereby identify the process of generating prediction, explanation and sophistication. For this study, a framework for mental simulation process and strategy based on literary research was developed and content was validated from four experts of science education. This study was participated by 10 preliminary elementary school teachers, and a total of 20 cases were gathered for two thought experiment tasks based on the think-aloud method. The results were as follows: First, mental simulation process described based on the seven elements of 'perception,' 'interpretation,' 'statement of initial representation,' 'running imagistic simulation,' 'identifying result of simulation,' 'identifying alignment' and 'restatement structured representation.' The study confirmed that initial representation by interpreting related concepts and running imagistic simulation a number of times to develop explanation and prediction. Second, the study identified the use of strategies to enhance simulation such as 'zoom in,' 'partition,' 'dimensional enhancement,' 'dimensional reduction,' 'remove,' 'replace' and 'extreme case.' Running spatial transformation that uses strategy to enhance simulation contributed to discovering mechanism elements in problematic situations.

• Journal of Korean Society of Transportation
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• v.34 no.6
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• pp.489-498
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• 2016

The objective of this study is to develop road traffic accident model involving child pedestrian especially at school zones and its surrounding area. The analysis is based upon traffic accident data collected near sixty elementary schools in City of Cheongju during 2012 and 2014. This study results in two statistical models ; one is to predict the number of road traffic accidents involving children, and the other is to predict EPDO(Equivalent Prperty Damage Only). These models are represented as Poisson models. which are statistically significant with the likelihood ratios of 0.533 and 0.273. The common explanatory variables of these models are the ratio of road section with more than 4 lanes, the number of entrance and exit, the number of signalized crosswalk in school zone, the number of school zone signage including road surface marking, and the number of speed limit signs. The specific variables are the length of road stretch in school zone, the number of reflector mirrors, and the number of signalized crosswalk outside school zone. It is concluded that these types of road safety facilities can reduce the number of traffic accidents involving children at school zones and its surrounding area.

• Journal of Korean Society on Water Environment
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• v.26 no.5
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• pp.841-849
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• 2010

Soil erosion is an natural phenomenon. However accelerated soil erosion has caused many environmental problems. To reduce soil loss from a watershed, many management practices have been proposed worldwide. To develop proper and efficient soil erosion best management practices, soil erosion rates should be estimated spatially and temporarily. The Universal Soil Loss Equation (USLE) and USLE-based soil erosion and sediment modelling systems have been developed and tested in many countries. The Sediment Assessment Tool for Effective Erosion Control (SATEEC) system has been developed and enhanced to provide ease-of-use interface to the USLE users. However many researchers and decision makers have requested to enhance the SATEEC system for simulation of soil erosion and sediment reflecting effects of single storm event. Thus, the SATEEC R factors were estimated based on 5 day antecedent rainfall data. The SATEEC 2.1 daily R factor was applied to the study watershed and it was found that the R2 and EI values (0.776 and 0.776 for calibration and 0.927 and 0.911 for validation) with the daily R were greater than those (0.721 and 0.720 for calibration and 0.906 and 0.881 for validation) with monthly R, which was available in the SATEEC 2.0 system. As shown in this study, the SATEEC with daily R can be used to estimate soil erosion and sediment yield at a watershed scale with higher accuracy. Thus the SATEEC with daily R can be efficiently used to develop site-specific soil erosion best management practices based on spatial and temporal analysis of soil erosion and sediment yield at a daily-time step, which was not possible with USLE-based soil erosion modeling system.

• Journal of Korean Society on Water Environment
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• v.29 no.3
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• pp.365-376
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• 2013

The purpose of this study was to evaluate effects of spatio-temporal changes in land uses and rainfall magnitude using the Soil and Water Assessment Tool (SWAT). Prior of application of the model to real-world problem, the model should be calibrated and validated properly. In most modeling approaches, the validation process is done assuming no significant changes occurring at the study watershed between calibration and validation periods, which is not proper assumption for agricultural watersheds. If simulated results obtained with calibrated parameters match observed data with higher accuracy for validation period, this does not always mean the simulated result represents rainfall-runoff, pollutant generation and transport mechanism for validation period because temporal and spatial variables and rainfall magnitude are often not the same. In this study SWAT was applied to Mandae study watershed in Korea to evaluate effects of spatio-temporal changes in landuses using 2009 and 2010 crop data for each field at the watershed. The Nash-Sutcliffe model efficiency (NSE) values for calibration and validation with either 2009 or 2010 was evaluated and the NSE value for calibration with 2009 and calibration with 2010 were compared. It was found that if there is substantial change in land use and rainfall, model calibration period should be determined to reflect those changes. Through these approaches, inherent limitation of the SWAT, which does not consider changes in land uses over the simulation period, was investigated. Also, Effects of changes in rainfall magnitude during calibration process were analyzed.

• Journal of Korea Water Resources Association
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• v.36 no.6
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• pp.925-936
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• 2003

The objective of this study is to suggest new drawing methods of isochrones using GIS. For this purpose the Unit Hydrograph (UH) of studied watershed for instantaneous rainfall suggested by Clark have been determined by routing the time-area curve through a single linear reservoir. To evaluate constructing methods of isochrones three methods has been examined; Channel Profile and Clark-kict method; Laurenson method; Average velocity method of S.C.S. Also, these methods have been recomposed by GIS in this study. To apply first method, spatial modeling, the vector based on the stream network and Route_System measuring a distance between points has been used. A raster based on the flow direction grid from burn DEM and the slope grid from original DEM has been applied for the second method. The third method has been applied by a raster based on the landuse grid and a velocity function expressed by slope. Results by these three methods have been evaluated with observed hydrograph, and the method using average velocity method of S.C.S shows more reasonable results comparatively.

• Journal of Korea Water Resources Association
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• v.44 no.11
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• pp.863-873
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• 2011

It has been known that soil erosion caused by water has been a serious problem worldwide. Thus various modeling techniques for conservationists, farmers, and other land users have been developed and utilized to estimate effects of numerous site-specific Best Management Practices on soil erosion reduction. The physical process-based WEPP model would provide both temporal and spatial estimates of soil loss within small watersheds and for hillslope profiles within small watersheds. Thus, the WEPP watershed version was applied to study watershed, located at Jawoon-ri, Gangwon to simulate diversion ditch and vegetated swale with detailed input data set. The sediment yield and runoff reduction rates reduced by 5.8% and 29.6% with diversion ditch and 9.8% and 14.5% with vegetated swale. With vegetated diversion ditch, runoff and sediment yield could be reduced by 11.8% and 40.4%, respectively. Based on the results obtained in this study, the WEPP model would be an useful tool to measure runoff and sediment yield reduction and establish site-specific sediment reduction best management plan.