• Korean Journal of Environmental Biology
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• v.33 no.1
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• pp.45-52
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• 2015

Acute toxicity tests for 5 organic solvents were conducted using Euglena agilis carter (E. agilis), a Korean domestic organism. Organic solvents decreased the growth rate of E. agilis in a dose dependent manner. The toxicity to E. agilis was increased in the order of chloroform>acetone${\geq}$ethanol${\geq}$methanol>DMSO based on $EC_{50}$ values from growth test. Organic solvents also induced cell motility and morphological changes of E. agilis. Especially significant effects on the cell swimming velocity, motility, and compactness were observed for chloroform at the concentration of $EC_{50}$ calculated from 96 hr growth test. Overall, toxic responses of E. agilis to test substances are comparable to or more sensitive than D. magna, M. macrocopa and V. fischeri. Our study demonstrates that E. agilis can be a putative ecotoxicity test model organism to assess domestic water quality. Results obtained from this study can be applied to establish the standard test guidelines for ecotoxicity test using E. agilis.

• Journal of Korea Water Resources Association
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• v.43 no.1
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• pp.67-79
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• 2010

Korea water resources corporation (K-Water) has developed the real-time water resources management system for the Nakdong and the Geum River basin to efficiently operate multi-purpose dams in the basins. This study has extended to the Han River basin for providing an effective ending target storage of a month to the real-time water resources management system using Sampling Stochastic Dynamic Programming (SSDP), consequently increasing the efficiency of the reservoir system. The optimization model were developed for three reservoirs, named Soyang, Chungju, and Hwacheon, with high priority in terms of the amounts of effective capacity and water supply for the basin. The number of storage state variable for each dam to set an optimization problem has been assigned from the results of sensitivity analysis. Compared with the K-water operating policy with the target water supply elevations, the optimization model suggested in this study showed that the shortfalls are decreased by 37.22 MCM/year for the required water demands in the basin, even increasing 171 GWh in hydro electronic power generation. In addition, the result of a reservoir operating system during the drawdown period applied to real situation demonstrates that additional releases for water quality or hydro electronic power generation would be possible during the drawdown period between 2007 and 2008. On the basis of these simulation results, the applicability of the SSDP model and the reservoir operating system is proved. Therefore, the more efficient reservoir operation can be achieved if the reservoir operating system is extended further to other Korean basins.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2003.04a
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• pp.472-477
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• 2003

멸종위기종의 서식지를 효율적으로 관리하기 위해서는 해당 종의 서식 가능한 지역의 분포를 알아야 한다. 본 연구의 목적은 GIS와 퍼지집합을 이용하여 산양(Nemorhaedus caudatus)의 서식지적합성모형을 개발하여 멸종 위기종의 서식지를 관리하기 위한 정보를 제공하는 것이다. 산양의 서식지적합성모형 개발을 위한 본 연구의 주요내용은 다음과 같다. 첫째, 산양 서식지 이용에 관한 기존 연구를 바탕으로 산양의 잠재적 서식지 환경변수를 분류하였으며, 분석 대상지의 산양 흔적 조사를 통해 서식지 환경변수의 재분류 및 x²검정(Chi-square test)을 통한 변수들의 유용성을 파악하고, 쌍체비교를 통한 환경변수별 가중치를 계산하였다. 둘째, 기존 부울논리(boolean logic)의 단점을 보완하기 위해 현장 조사의 결과를 바탕으로 퍼지논리(fuzzy logic)에 의한 산양 서식지의 각 환경변수별 주제도를 작성하고, 주제도들의 상관관계를 분석하여 상호 관련성이 높은 변수들의 중복을 피하였다. 셋째, 환경변수별 주제도와 변수별 가중치를 바탕으로 다기준평가기법(MCE, Multi-Criteria Evaluation)을 이용하여 분석대상지의 산양 서식지적합성모형을 개발하였다. 마지막으로, 개발된 서식지적합성모형의 타당성을 검증하기 위해 분석대상지 외부 지역을 대상으로 검증을 실시하였다. 분석 결과 분석대상지의 분류정확도는 서식가능성 0.5를 기준으로 93.94%의 매우 높은 분류정확도를 나타내었으며, 검증대상지에서는 95.74%의 분류정확도를 나타내어 본 모형의 분류정확도는 일관성이 높은 것으로 판단되었다. 또한 전체 공원구역에서 서식가능성 0.5이상의 면적은 59%를 차지하였다.퇴적이 우세한 것으로 관측되었다.보체계의 구축사업의 시각이 행정정보화, 생활정보화, 산업정보화 등 다양한 분야와 결합하여 보다 큰 시너지 효과와 사용자 중심의 서비스 개선을 창출할 수 있는 기반을 제공할 것을 기대해 본다.. 이상의 결과를 종합해볼 때, ${\beta}$-glucan은 고용량일 때 직접적으로 또는 $IFN-{\gamma}$ 존재시에는 저용량에서도 복강 큰 포식세로를 활성화시킬 뿐 아니라, 탐식효율도 높임으로써 면역기능을 증진 시키는 것으로 나타났고, 그 효과는 crude ${\beta}$-glucan의 추출조건에 따라 달라지는 것을 알 수 있었다.eveloped. Design concepts and control methods of a new crane will be introduced in this paper.and momentum balance was applied to the fluid field of bundle. while the movement of′ individual material was taken into account. The constitutive model relating the surface force and the deformation of bundle was introduced by considering a representative prodedure that stands for the bundle movement. Then a fundamental equations system could be simplified considering a steady state of the process. O

• Korean Journal of Construction Engineering and Management
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• v.15 no.2
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• pp.112-121
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• 2014

After IMF bailout crisis in Korea, project financing has been employed as a major funding vehicle for the housing development. In 2008, the recession of housing market due to the global financial crisis had an significant impact on the increasing insolvent site of PF based housing development project, resulting in serious impact to whole economy as a chain effect. In order to resolve this vicious circle of bankruptcy, the major construction companies were urged to take over the insolvent sites and invest to them for normal project exit, and finally play a critical role in normalization of market. Therefore, this study aims to define the core factors for decision making to invest to insolvent site and find out differences among constructors, developers, financial lenders. The results from AHP analysis, the profitability was the most important factor to constructors. Moreover, even though the location merit is little less, through competitive price, we can assure that stable profitability is most important factor to decide to invest in insolvent site. In conclusion, the price is cheap, is highly feasible, if the land secured, major construction company will participate in a PF business investment. These findings were verified by the investment case of major construction company.

• Journal of Korea Water Resources Association
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• v.41 no.10
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• pp.969-982
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• 2008

As hydrological models have been progressively developed, they are recognized as appropriate tools to manage water resources. Especially, the need to evaluate the effects of landuse and climate change on hydrological phenomena has been increased, which requires powerful validation methods for the hydrological models to be employed. As measured streamflow data at many locations may not be available, or include significant errors in application of hydrological models, streamflow data simulated by models only might be used to conduct hydrological analysis. In many cases, reducing errors in model simulations requires a powerful model validation method. In this research, we demonstrated a validation methodology of SWAT model using observed flow in two basins with different physical characteristics. First, we selected two basins, Gap-cheon basin and Yongdam basin located in the Guem River Basin, showing different hydrological characteristics. Next, the methodology developed to estimate parameter values for the Gap-cheon basin was applied for estimating those for the Yongdam basin without calibration a priori, and sought for validation of the SWAT. Application result with SWAT for Yongdam basin showed $R_{eff}$ ranging from 0.49 to 0.85, and $R^{2}$ from 0.49 to 0.84. As well, comparison of predicted flow and measured flow in each subbasin showed reasonable agreement. Furthermore, the model reproduced the whole trends of measured total flow and low flow, though peak flows were rather underestimated. The results of this study suggest that SWAT can be applied for predicting effects of future climate and landuse changes on flow variability in river basins. However, additional studies are recommended to further verify the validity of the mixed method in other river basins.

• Journal of the Korean Institute of Gas
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• v.22 no.6
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• pp.44-51
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• 2018

As the LNG storage tank is aged, if there is a crack in the outer wall concrete or corrosion of the reinforcing steel, there is a risk of a major accident such as collapse of the structure depending on the type and degree of damage. Since 2014, LNG storage tanks have undergone precise safety diagnosis and safety inspection has been carried out. The condition evaluation criteria for each component have been revised and applied in January 2016. The condition evaluation standard is to evaluate the status of storage tanks based on the appearance survey and material test results of LNG storage tanks and it is important for maintenance. In addition, the representative condition evaluation standard that shows the comprehensive state of each LNG storage tank is important in maintenance, but the related standard for LNG storage tank outer concrete is not available in Korea and abroad, and development of the condition evaluation standard is necessary. In this paper, we examined the structural characteristics of LNG storage tanks, analyzed the status of the condition evaluation criteria for each member, and developed a comprehensive status rating system by weighting the members. We used the AHP(Analytic Hierarchy Process) technique and developed a representative conditon evaluation criteria through surveys of professional organizations.

• Korean Journal of Remote Sensing
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• v.38 no.5_2
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• pp.669-683
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• 2022

The frequency and damage of forest fires have tended to increase over the past 20 years. In order to effectively respond to forest fires, information on forest fire damage should be well managed. However, information on the extent of forest fire damage is not well managed. This study attempted to present a method that extracting information on the area of forest fire in real time and quasi-real-time using visible infrared imaging radiometer suite (VIIRS) images. VIIRS data observing the Korean Peninsula were obtained and visualized at the time of the East Coast forest fire in March 2022. VIIRS images were classified without supervision using iterative self-organizing data analysis (ISODATA) algorithm. The results were reclassified using the relationship between the burned area and the location of the flame to extract the extent of forest fire. The final results were compared with verification and comparison data. As a result of the comparison, in the case of large forest fires, it was found that classifying and extracting VIIRS images was more accurate than estimating them through forest fire occurrence data. This method can be used to create spatial data for forest fire management. Furthermore, if this research method is automated, it is expected that daily forest fire damage monitoring based on VIIRS will be possible.

• The Journal of Bigdata
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• v.8 no.1
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• pp.157-165
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• 2023

Seafood is a major source of protein in many countries and its consumption is increasing. In Korea, consumption of seafood is increasing, but self-sufficiency rate is decreasing, and the importance of safety management is increasing as the amount of imported seafood increases. There are hundreds of species of aquatic products imported into Korea from over 110 countries, and there is a limit to relying only on the experience of inspectors for safety management of imported aquatic products. Based on the data, a model that can predict the customs inspection results of imported aquatic products is developed, and a machine learning classification model that determines the non-conformity of aquatic products when an import declaration is submitted is created. As a result of customs inspection of imported marine products, the nonconformity rate is less than 1%, which is very low imbalanced data. Therefore, a sampling method that can complement these characteristics was comparatively studied, and a preprocessing method that can interpret the classification result was applied. Among various machine learning-based classification models, Random Forest and XGBoost showed good performance. The model that predicts both compliance and non-conformance well as a result of the clearance inspection is the basic random forest model to which ADASYN and one-hot encoding are applied, and has an accuracy of 99.88%, precision of 99.87%, recall of 99.89%, and AUC of 99.88%. XGBoost is the most stable model with all indicators exceeding 90% regardless of oversampling and encoding type.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.4
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• pp.567-575
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• 2024

The government and local governments are utilizing regulations, policies, and various project management techniques at each project stage to effectively and systematically manage public construction projects. However, the increase in construction costs continues to occur. In order to solve these problems, this study attempted to collect cases of existing public construction projects and analyze historical data. And it would like to derive the impact factor of increased construction costs. Based on the results, a plan was proposed to prevent the causes of increase and minimize in construction costs. The main reasons for the increase in costs were the occurrence of civil petition, differences between design documents and site conditions, and changes due to requests from the owner and changes in the business plan. And to solve these problems, this study proposed improvement for each cause from an institutional perspective, along with interview with experts and project owners. The results of this study are significant in improving the process of existing public construction process and presenting key inspection and review items for each major inspection stage in order to solve problem resulting from the analysis of the performance of public construction projects.

• Korean Journal of Environmental Biology
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• v.42 no.3
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• pp.301-310
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• 2024

Endemic species are defined as taxa that naturally inhabit and grow within a specific area. Because they easily face regional extinction, continuous management is required. In this study, stable isotope analysis, length-weight relationships (LWRs), and condition factor (K) estimation were applied to oily bitterling Acheilognathus koreensis inhabiting three representative rivers including the Geum River basin, Seomjin River basin, and Tamjin River basin to compare ecological property and related biological conditions. Based on the corrected isotope value to account for difference in carbon isotope ratio (δ¹³C) of POM, Δδ¹³C_{A.koreensis-POM}, estimated isotope niche areas of A. koreensis between Geum and Tamjin River populations were highly overlapped while those of the Seomjin River population were discriminated from other habitats, indicating differences in major diet sources among habitats. In addition, LWRs for the Seomjin River population showed a good growth with a b value of 3.155 compared to Geum and Tamjin River populations which showed relatively low growth rates of 2.888 and 2.968, respectively. Fluctuation of the K value of the A. koreensis tended to decrease with growth in the Geum River while that of the Seomjin River population exhibited the highest increasing trend. This study confirmed differences in diet resources among habitats for A. koreensis, which resulted growth and fatness variations for each population. Our results can be used as basic information for effective conservation and management strategies of A. koreensis populations.