• 한국해안·해양공학회논문집
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• 제20권5호
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• pp.482-490
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• 2008

연안 및 항만구조물의 설계에서 최극 고조위는 매우 중요한 환경인자이다. 특히, 최극 고조위의 분포정보는 최근 부각되고 있는 신뢰성 설계에 필수적인 요소이다. 본 연구에서는 국립해양조사원에서 제시한 한국연안 주요 23개 검조소의 최극조위자료를 이용하여 극치분포 분석을 수행하였다. 특성분석에 사용된 극치분포함수는 Generalized Extreme Value, Gumbel 그리고 Weibull 분포이며, 각 분포함수의 매개변수는 모멘트법, 최우도법 그리고 확률가중모멘트법 등 3가지방법으로 추정하였다. 또한, 극치분포함수의 적합성은 95% 신뢰도 수준으로 $X^2$ 및 K-S 검정을 실시하였다. 그 결과, 23개 검조소의 최극 고조위는 Gumbel 분포형이 가장 적합한 모형으로 파악되었으며, 최적 추정된 매개변수 및 재현기간별 최극 고조위 정보를 제시하였다. 심 등(1992)이 제시한 인천, 제주, 여수, 부산, 묵호에 대한 극치해면값은 본 논문에서 산정한 결과에 비하여 작게 나타났다.

• 한국태양에너지학회 논문집
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• 제32권1호
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• pp.15-24
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• 2012

IEC 61400-1 requires design lifetime of wind turbines at least 20 years, thus wind turbine should be assured for structural safety through load assessment. DLCs have been defined with respect to the load assessment in IEC 61400-1. In addition, if the extreme design values for DLC1.3 are equal or exceed the extreme design value for DLC1.1, DLC1.1 may be omitted. To omit DLC1.1, scale factor (c) will be increased in DLC1.3. However, this particular adjustment is not specified guidelines. Thus, this study was conducted. DLC1.1 was calculated for extrapolation of 50 years-extreme events using several probability distribution functions and fitting methods. And DLC1.3 was calculated for up to seven different values of scale factor (c) with $2{\leq}c{\leq}5$ in steps of 0.5. Finally, in this study, scale factor (c) that was the value of 4.51 was determined.

• 한국안전학회지
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• 제25권3호
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• pp.112-117
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• 2010

This study presents a methodology to evaluate the driving safety of vehicles against localized high wind on the roads over the valleys or along the coasts. Risk level for vehicle accident is derived from the side slip caused by cross wind, and then safety criteria based on reliability for driving stability are defined. The level of safety is classified according to probability of exceeding against wind speed using the concept of extreme value statistics. To attain the safety level of vehicle on bridges, numerical simulations using Computational Fluid Dynamics(CFD) are performed. Based on this result, risk reduction and quality improvement is expected through analysis for each alternative in bridges design, construction and operation & maintenance stage with proposed process

• 상하수도학회지
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• 제26권2호
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• pp.321-329
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• 2012

In this study, statistical analysis under both stationary and non-stationary climate was conducted for rainfall data measured in Seoul. Generalised Extreme Value (GEV) distribution and Gumbel distribution were used for the analysis. Rainfall changes under the non-stationary climate were estimated by applying time variable (t) to location parameter (${\xi}$). Rainfall depths calculated in non-stationary climate increased by 1.1 to 6.2mm and 1.0 to 4.6mm for the GEV distribution and gumbel distribution respectively from those stationary forms. Changes in annual maximum rainfall were estimated with rate of change in the location parameter (${\xi}1{\cdot}t$), and temporal changes of return period were predicted. This was also available for re-evaluating the current sewer design return period. Design criteria of sewer system was newly suggested considering life expectance of the system as well as temporal changes in the return period.

• Steel and Composite Structures
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• 제3권3호
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• pp.185-198
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• 2003

The concept of performance based seismic design has been gradually accepted by the earthquake engineering profession recently, in which the cost-effectiveness criterion is one of the most important principles and more attention is paid to the structural performance at the inelastic stage. Since there are many uncertainties in seismic design, reliability analysis is a major task in performance based seismic design. However, structural reliability analysis may be very costly and time consuming because the limit state function is usually a highly nonlinear implicit function with respect to the basic design variables, especially for the complex large-scale structures for dynamic and nonlinear analysis. Understanding statistical properties of the structural inelastic deformation, which is the aim of the present paper, is helpful to develop an efficient approximate approach of reliability analysis. The present paper studies the statistical properties of the maximum elastoplastic story drift of steel frames subjected to earthquake load. The randomness of earthquake load, dead load, live load, steel elastic modulus, yield strength and structural member dimensions are considered. Possible probability distributions for the maximum story are evaluated using K-S test. The results show that the choice of the probability distribution for the maximum elastoplastic story drift of steel frames is related to the mean value of the maximum elastoplastic story drift. When the mean drift is small (less than 0.3%), an extreme value type I distribution is the best choice. However, for large drifts (more than 0.35%), an extreme value type II distribution is best.

• Journal of Advanced Research in Ocean Engineering
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• 제4권4호
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• pp.185-194
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• 2018

In this study, the extreme sloshing pressure was predicted using various statistical models: three-parameter Weibull distribution, generalized Pareto distribution, generalized extreme value distribution, and three-parameter log-logistic distribution. The estimation of sloshing impact pressure is important in design of liquid cargo tank in severe sea state. In order to get the extreme values of local impact pressures, a lot of model tests have been carried out and statistical analysis has been performed. Three-parameter Weibull distribution and generalized Pareto distribution are widely used as the statistical analysis method in sloshing phenomenon, but generalized extreme value distribution and three-parameter log-logistic distribution are added in this study. Additionally, statistical distributions are fitted to peak pressure data using three different parameter estimation methods. The data were obtained from a three-dimensional sloshing model text conducted at Seoul National University. The loading conditions were 20%, 50%, and 95% of tank height, and the analysis was performed based on the measured impact pressure on four significant panels with large sloshing impacts. These fittings were compared by observing probability of exceedance diagrams and probability plot correlation coefficient test for goodness-of-fit.

• Wind and Structures
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• 제9권3호
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• pp.179-191
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• 2006

Parent wind data are often acknowledged to fit a Weibull probability distribution, implying that wind epoch maxima should fall into the domain of attraction of the Gumbel (Type I) extreme value distribution. However, observations of wind epoch maxima are not fitted well by this distribution and a Generalised Extreme Value (GEV) analysis leading to a Type III fit empirically appears to be better. Thus there is an apparent paradox. The reasons why advocates of the GEV approach seem to prefer it are briefly summarised. This paper gives a detailed analysis of the errors involved when the GEV is fitted to epoch maxima of Weibull origin. It is shown that the results in terms of the shape parameter are an artefact of these errors. The errors are unavoidable with the present sample sizes. If proper significance tests are applied, then the null hypothesis of a Type I fit, as predicted by theory, will almost always be retained. The GEV leads to an unacceptable ambiguity in defining design loads. For these reasons, it is concluded that the GEV approach does not seem to be a sensible option.

• Wind and Structures
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• 제25권3호
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• pp.261-282
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• 2017

The probabilistic information of directional extreme wind speeds is important for precisely estimating the design wind loads on structures. A new joint probability distribution model of directional extreme wind speeds is established based on observed wind-speed data using multivariate extreme value theory with the t-Copula function in the present study. At first, the theoretical deficiencies of the Gaussian-Copula and Gumbel-Copula models proposed by previous researchers for the joint probability distribution of directional extreme wind speeds are analysed. Then, the t-Copula model is adopted to solve this deficiency. Next, these three types of Copula models are discussed and evaluated with Spearman's rho, the parametric bootstrap test and the selection criteria based on the empirical Copula. Finally, the extreme wind speeds for a given return period are predicted by the t-Copula model with observed wind-speed records from several areas and the influence of dependence among directional extreme wind speeds on the predicted results is discussed.

• 한국해안해양공학회지
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• 제16권3호
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• pp.130-141
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• 2004

연안 및 항만구조물의 설계에서 심해 설계파는 매우 중요한 환경인자이다. 특히, 심해설계파고의 분포 정보는 최근 부각되고 있는 신뢰성 설계에 필수적인 요소이다. 본 연구에서는 한국해양연구원(2003)에서 제시한 1979년부터 1998년까지의 한국연안 67개 지점의 16방향별 최대 유의파 산출자료를 이용하여 극치분포 분석을 수행하였다. 특성분석에 사용된 극치분포함수는 Weibull, Gumbel, Log-Pearson Type-III, Lognormal 분포이며, 각 분포함수의 매개변수는 모멘트법, 최우도법 그리고 확률가중모멘트법으로 추정하였다. 또한, 극치분포함수의 적합성은 95% 신뢰도 수준으로 $\chi$$^2$및 K-S 검정을 실시하였다. 그 결과, 한국연안의 심해 설계파고는 Gumbel 분포형이 가장 적합한 모형으로 파악되었으며, 최적 추정된 매개변수 및 재현기간 50년에 대한 심해 설계파고 정보를 제시하였다.

• 대한건축학회논문집:계획계
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• 제36권2호
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• pp.25-32
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• 2020

The purpose of this study is to estimate the economic value of architectural aesthetic using the contingent valuation method and to analyze the value-giving characteristics. The site survey was conducted based on the scenario of Dong-daemun Design Plaza, which is recognized as a work of outstanding architectural aesthetic. Based on 307 opinions collected, the main results are as follows: First, it could be confirmed that the higher the level of architectural aesthetic, the higher the payment amount was. The result of estimating the value of the architectural aesthetic on the basis of the fixed amount levy showed that the average payment amount was 8,859 won per person. The average payment amount was 13,014 won per person when the rejector of payment was excluded. The value of architectural aesthetic was about 13.72% of total construction cost. Second, free riding, which occurs mainly in the measurement of the value of public goods or environmental goods, appeared. This tendency is stronger in the elderly than in the younger, and in the differential amount levy than in the fixed amount levy. Third, the extreme subjectivity of architectural aesthetic value could be confirmed. While there are a lot of extreme denials of payments such as 0 won, the high-income was willing to pay a substantial amount. Fourth, it was confirmed that income factors was partly involved in the measured value.