• 전기학회논문지P
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• 제56권1호
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• pp.56-62
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• 2007

In this paper, design method for power tower hazard diagnosis/predition system based on UsN was proposed. The proposed method used multi-hybrid sensors to measure rotation, displacement, and inclination state of power tower, and made decision/prediction of hazard of power tower. System design was made with requirement analysis of monitoring for transmission power facility and use of MEMS and optic fiber sensors. For hazard decision, analysis of correlation was made using sensor output. LN based on IEC61850,international standard for digital substation, was also proposed. For transmission facility monitoring, digital substation and power tower were considered as parts of power facility networks.

• Communications for Statistical Applications and Methods
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• 제27권6호
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• pp.675-688
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• 2020

In survival analysis of observational data, the inverse probability weighting method and the Cox proportional hazards model are widely used when estimating the causal effects of multiple-valued treatment. In this paper, the two kinds of weights have been examined in the inverse probability weighting method. We explain the reason why the stabilized weight is more appropriate when an inverse probability weighting method using the generalized propensity score is applied. We also emphasize that a marginal hazard ratio and the conditional hazard ratio should be distinguished when defining the hazard ratio as a treatment effect under the Cox proportional hazards model. A simulation study based on real data is conducted to provide concrete numerical evidence.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2008년도 정기총회 및 학술발표대회
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• pp.213-216
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• 2008

In this study, reflection coefficients of regular and random waves propagating over multi-arrayed trenchs are calculated respectively. When the row of trench is 3, the reflection coefficient of regular waves is more than 0.7 as maximum value. Similarly, when the row of trench is 3 and $d/L_1$ is 0.22, reflection coefficient of multi-directional random waves is more than 0.4 maximally.

• 한국방재학회 논문집
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• 제10권6호
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• pp.73-80
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• 2010

최저 안전율 또는 최대 파괴확률을 기반으로 하는 기존의 사면안정해석에 대하여, 지반물성과 해석모델이 갖는 고유 불확실성을 최소화하고, 사면안정해석에서 다양한 안정해석모델과 그에 따른 파괴형상을 반영할 수 있도록, 다중 파괴모드를 고려한 사면의 신뢰성해석기법을 제안하였다. 파괴확률의 산정에는 체계 신뢰성해석분야에서 최근 도입된 선형계획법에 의한 최적화를 이용하였다. 이를 통하여 여러 가지 해석모델을 신뢰성 기반으로 동시에 고려하여 해석할 수 있다. 선형계획법에 의한 다중 파괴 모드를 고려한 파괴확률 산정기법을 이용하여 단순 사면의 경사도 결정을 위한 최적 설계를 검토하였다. 그 결과, 동시 파괴확률을 이용하면, 대상으로 하는 사면안정해석모델과 파괴형상 및 파괴확률을 복합적으로 고려할 수 있기 때문에 개선된 안전성을 확보할 수 있을 것으로 판단된다.

• 한국방재학회 논문집
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• 제9권5호
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• pp.93-102
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• 2009

본 연구는 미호천 유역을 대상으로 유량곡선의 세부적인 특성을 고려한 다목적함수를 적용하여 Probability Distribution Model(PDM) 모형의 유량모의성능을 검토하였다. PDM은 유역을 한 개의 단위구역으로 개념화한 집중형 강우유출모형으로 영국의 지역화 연구 및 홍수량 산정방법에 대표적으로 이용되고 있다. PDM 모형의 5개 매개변수를 Monte Carlo 방법에 기반을 둔 분석도구(MCAT, Monte Carlo Analysis Toolkit)를 활용하여 사후검정분포, 검정근거 및 민감도 분석 등을 수행하였으며, 모형의 매개변수 중 cmax와 k(q)만이 뚜렷한 검정 근거가 있고 나머지 변수들은 동등성의 영향을 확인하였다. 또한, 유량곡선의 고유량 및 저유량의 특성을 맞춘 목적함수의 Trade-off를 고려한 매개변수의 파레토 최적해를 산정한 결과, 모든 목적에 최대한 부합하는 유량 산정의 가능성을 제시하였다. 검정(calibration)기간에서 NS*E=0.035, FSB=0.161, FDBH= 0.809로 안정적이며 만족할만한 모의성능을 나타내었고, 검증(validation)기간에 대해서도 안정적인 모의성능을 나타내었다.

• 한국방재학회:학술대회논문집
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• 한국방재학회 2007년도 정기총회 및 학술발표대회
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• pp.71-74
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• 2007

Thin-walled multicell box girders subjected to an eccentric load can be produced the three global behaviors of flexure, torsion, and distortion. But it is very difficult to evaluate each influences of major behaviors numerically. If we can decompose an eccentric load P into flexural, torsional, and distortional forces, we can execute quantitative analysis each influences of major behaviors. Decomposition of Applied Load for Thin-walled Rectangular multi-cell box girders is researched by Park, Nam-Hoi(Development of a multicell Box Beam Element Including Distortional Degrees of Freedom, 2003). But researches about thin-walled trapezoidal multi-cell section is insufficient. So, this paper deals with decomposition process and independent analysis method of multi-cell box girders include trapezoidal section.

• 국제강구조저널
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• 제18권4호
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• pp.1470-1481
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• 2018

Building-level response to post-earthquake fire hazards in steel buildings has been assessed using primarily two-dimensional analyses of the lateral force resisting system. This approach may not adequately consider potential vulnerabilities in the gravity framing system. For this reason, three-dimensional (3D) finite element models of a 10-story case study building with perimeter moment resisting frames were developed to analyze post-earthquake fire events and better understand building response. Earthquakes are simulated using ground motion time histories, while Eurocode parametric time-temperature curves are used to represent compartment fires. Incremental dynamic analysis and incremental fire analysis procedures capture a range of hazard intensities. Findings show that the structural response due to earthquake and fire hazards are somewhat decoupled from one another. Regardless of the level of plastic hinging present in the moment framing system due to a seismic event, gravity column failure is the initiating failure mode in a fire event.

• 대한예방의학회:학술대회논문집
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• 대한예방의학회 2003년도 제11회 춘계 심포지움 연제집
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• pp.30-37
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• 2003

o Cohort study became the major approach to study of chronic diseases such as CVD and cancer o Cohort can be population-based or volunteer-based o Types of be population-be categorized by source population and selection mechanism o More and more cohort studies involve biological specimens, such as blood, urine, toenail, cheek cells, etc. o Multi-center and multi-national collaboration is an effective way to increase sample size. o Current statistical method typically use time-to-event analysis by Cox proportional hazard model.

• 한국가스학회:학술대회논문집
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• 한국가스학회 2002년도 추계학술발표회 논문집
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• pp.149-155
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• 2002

• 대한원격탐사학회지
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• 제21권5호
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• pp.393-404
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• 2005

As multi-source spatial data fusion mainly deal with various types of spatial data which are specific representations of real world with unequal reliability and incomplete knowledge, proper data representation and uncertainty analysis become more important. In relation to this problem, this paper presents and applies an advanced data representation methodology for different types of spatial data such as categorical and continuous data. To account for the uncertainties of both categorical data and continuous data, fuzzy boundary representation and smoothed kernel density estimation within a fuzzy logic framework are adopted, respectively. To investigate the effects of those data representation on final fusion results, a case study for landslide hazard mapping was carried out on multi-source spatial data sets from Jangheung, Korea. The case study results obtained from the proposed schemes were compared with the results obtained by traditional crisp boundary representation and categorized continuous data representation methods. From the case study results, the proposed scheme showed improved prediction rates than traditional methods and different representation setting resulted in the variation of prediction rates.