• Proceedings of the Korea Water Resources Association Conference
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• 2007.05a
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• pp.1900-1904
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• 2007

지금까지 수공구조물의 설계와 기존 시설의 안전도를 평가시 수문, 수리 및 경제학적 함수들에서 발생하는 불확실성을 설명하기 위하여 안전율 또는 여유고를 증가시키거나 이들 정보의 양과 질을 증가시켜 데이터베이스를 확장하고 측정오차를 최소화시키며, 전통적인 통계해석을 적용하였다. 공공의 안전을 확보하기 위하여 설계과정에 안전율 또는 여유고가 도입되었으나 이것은 단순히 보다 높은 재현기간의 적용을 의미하며, 수문현상이 가지는 추계학적 특성보다 확정론적인 근거로부터 안전설계 개념이 개발되었다. 수자원 계획시 고려되는 부하와 저항은 확정론적인 고정치가 아니라 시간에 따라 변하고 동적이며, 무작위적이므로 확률 변수로서 고려되어야 한다. 이에 따라 최근 수자원 계획과정에서 불확실성 해석에 의한 위험도 분석 개념이 도입되고 있으며, 특히 이상기후 및 집중호우의 빈발, 급격한 도시화로 인한 유출양상의 변화 등으로 급증하고 있는 훙수피해를 감안할 때 설계빈도의 상향조정과 같은 확정론적인 방법보다는 매개변수 또는 함수의 불확실성을 고려한 위험도 해석의 필요성이 더욱 증대되고 있는 실정이다. 따라서 본 논문에서는 수자원 계획시 입력자료 및 매개변수의 불확실성과 불확실성의 분리를 고려한 홍수량의 산정 및 각 매개변수의 영향을 평가하여 홍수위험도 해석에 있어서 모델 매개변수의 영향 규명과 처리방안을 제시하고자 한다.

• Proceedings of the Korean Institute Of Construction Engineering and Management
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• autumn
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• pp.473-476
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• 2003

This paper presents a systematic risk assessment procedure with uncertainty modeling for general construction projects. Since the approach is able to effectively deal with all the related construction risks in terms of the assumed probability with conditional probability concept that systematically incorporate expert's experiences and subjective judgement, the proposed methods with uncertainty modeling is able to apply to all the construction projects inherent in lots of uncertain risk events. The fuzzy set theory is adopted to enhance risk assessment to effectively handle the vague and dynamic phenomenon of an event Therefore, the fuzzy-based risk assessment is very useful, for those countries, such as Korea, where objective probabilistic data for risk assessment is extremely rare, and thus the utilization of subjective judgmental data based on expert's experiences is inevitable.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.12
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• pp.1766-1771
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• 2003

House made differential mobility analyzer(DMA) is calibrated with NIST SRM 1691(300 nm PSL). Then the particle size and uncertainty for differential mobility analyzer(DMA) using the NIST SRM 1963(100 nm PSL). In result, calibration of prototype DMA is measured using 300 nm NIST SRM 1691, then sheath air flow was corrected 126.67 ㎤/s. Corrected sheath air flow is used in uncertainty measurement of prototype DMA. Uncertainty analysis is performed using NIST SRM 1963(100 nm PSL). The experimental result shows that NIST SRM 1963 is measured as 102.17 nm with a type A uncertainty of 0.33 nm.

• Proceedings of the Korea Water Resources Association Conference
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• 2010.05a
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• pp.610-614
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• 2010

지구온난화에 따른 이상기후 현상으로 불확실성에 대한 고려가 더욱 중요해진 지금 설계빈도의 무조건적인 상향조정에 의존하기보다는 추계학적 방법을 도입한 수문량의 확충 및 매개변수의 불확실성을 고려하기 위한 연구가 활발히 진행중이다. 본 연구에서는 강우발생의 불확실성을 반영하여 제내지에서의 침수 범위를 GIS상에서 검토하기 위해 log-ratio 방법, Johnson 시스템, 직교변환을 활용한 다변량 Monte Carlo 기법으로 추계학적 시간에 따른 강우변동을 생성하였다. 생성된 강우변동 결과를 토대로 수문분석, 홍수위 분석 등을 실시하고 FLUMEN 모형을 적용하여 해당유역에 대한 홍수범람시 침수범위를 산정하였다. 본 연구결과는 실제 강우의 불확실성을 반영하고 있어 시 공간적 강우특성이 반영된 유역별 주민대피지도, 홍수위험지도 등을 제작하는데 활용될 수 있을 것으로 기대된다.

• Journal of Distribution Science
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• v.7 no.2
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• pp.5-28
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• 2009

As a result of this study only a few Korean firms have a certain management methods designed to predict the possibility of risk occurrence and establishment of systematic countermeasure. Besides, the Korean firms do not have enough data on the risk of Chinese Market. The risk management department inside the firm does not function efficiently, and when it comes to investigation of risk, it heavily depends on that of local branches. Accordingly, in order to accurately recognize and manage, the firms need to not only specialize risk management department but also outsource by using a consulting firm.

• Journal of Korea Water Resources Association
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• v.51 no.5
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• pp.439-449
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• 2018

Many potential sources of bias are used in several steps of the radar-rainfall estimation process because the hydrological and meteorological radars measure the rainfall amount indirectly. Previous studies on radar-rainfall uncertainties were performed to reduce the uncertainty of each step by using bias correction methods in the quantitative radar-rainfall estimation process. However, these studies do not provide comprehensive uncertainty for the entire process and the relative ratios of uncertainty between each step. Consequently, in this study, a suitable approach is proposed that can quantify the uncertainties at each step of the quantitative radar-rainfall estimation process and show the uncertainty propagation through the entire process. First, it is proposed that, in the suitable approach, the new concept can present the initial and final uncertainties, variation of the uncertainty as well as the relative ratio of uncertainty at each step. Second, the Maximum Entropy Method (MEM) and Uncertainty Delta Method (UDM) were applied to quantify the uncertainty and analyze the uncertainty propagation for the entire process. Third, for the uncertainty quantification of radar-rainfall estimation at each step, two quality control algorithms, two radar-rainfall estimation relations, and two bias correction methods as post-processing through the radar-rainfall estimation process in 18 rainfall cases in 2012. For the proposed approach, in the MEM results, the final uncertainty (from post-processing bias correction method step: ME = 3.81) was smaller than the initial uncertainty (from quality control step: ME = 4.28) and, in the UDM results, the initial uncertainty (UDM = 5.33) was greater than the final uncertainty (UDM = 4.75). However uncertainty of the radar-rainfall estimation step was greater because of the use of an unsuitable relation. Furthermore, it was also determined in this study that selecting the appropriate method for each stage would gradually reduce the uncertainty at each step. Therefore, the results indicate that this new approach can significantly quantify uncertainty in the radar-rainfall estimation process and contribute to more accurate estimates of radar rainfall.

• Journal of Korea Water Resources Association
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• v.45 no.9
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• pp.861-874
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• 2012

To fulfill applicability of Soil and Water Assessment Tool (SWAT) model, it is important that this model passes through a careful calibration and uncertainty analysis. In recent years, many researchers have come up with various uncertainty analysis techniques for SWAT model. To determine the differences and similarities of typical techniques, we applied three uncertainty analysis procedures to Chungju Dam watershed (6,581.1 $km^2$) of South Korea included in SWAT-Calibration Uncertainty Program (SWAT-CUP): Sequential Uncertainty FItting algorithm ver.2 (SUFI2), Generalized Likelihood Uncertainty Estimation (GLUE), Parameter Solution (ParaSol). As a result, there was no significant difference in the objective function values between SUFI2 and GLUE algorithms. However, ParaSol algorithm shows the worst objective functions, and considerable divergence was also showed in 95PPU bands with each other. The p-factor and r-factor appeared from 0.02 to 0.79 and 0.03 to 0.52 differences in streamflow respectively. In general, the ParaSol algorithm showed the lowest p-factor and r-factor, SUFI2 algorithm was the highest in the p-factor and r-factor. Therefore, in the SWAT model calibration and uncertainty analysis of the automatic methods, we suggest the calibration methods considering p-factor and r-factor. The p-factor means the percentage of observations covered by 95PPU (95 Percent Prediction Uncertainty) band, and r-factor is the average thickness of the 95PPU band.

• 한국방재학회:학술대회논문집
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• 2009.02b
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• pp.112.1-112.1
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• 2009

• Proceedings of the Korea Water Resources Association Conference
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• 2003.05a
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• pp.317-320
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• 2003

• Proceedings of the Korea Water Resources Association Conference
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• 2002.05b
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• pp.989-994
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• 2002