• Proceedings of the Korea Water Resources Association Conference
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• 2021.06a
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• pp.332-332
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• 2021

도시화가 상당히 이뤄지고 기습적인 폭우의 발생이 불확실하게 나타나는 시점에서 재산 및 인명피해를 야기할 수 있는 내수침수에 대한 위험도가 증가하고 있다. 내수침수에 대한 예측을 위하여 실측강우 또는 확률강우량 시나리오를 참조하고 연구대상 지역에 대한 1차원 그리고 2차원 수리학적 해석을 실시하는 연구가 오랫동안 진행되어 왔으나, 수치해석 모형의 경우 다양한 수문-지형학적 자료 및 계측 자료를 요구하고 집약적인 계산과정을 통한 단기간 예측에 어려움이 있음이 언급되어 왔다. 본 연구에서는 위와 같은 문제점을 해결하기 위하여 단일 도시 배수분구를 대상으로 관측 강우 자료, 1, 2차원 수치해석 모형, 기계학습 및 딥러닝 기법을 적용한 실시간 홍수위험지도 예측 모형을 개발하였다. 강우자료에 대하여 실시간으로 홍수량을 예측할 수 있도록 LSTM(Long-Short Term Memory) 기법을 적용하였으며, 전국단위 강우에 대한 다양한 1차원 도시유출해석 결과를 학습시킴으로써 예측을 수행하였다. 침수심의 공간적 분포의 경우 로지스틱 회귀를 이용하여, 기준 침수심에 대한 예측을 각각 수행하였다. 홍수위험 등급의 경우 침수심, 유속 그리고 잔해인자를 고려한 홍수위험등급 공식을 적용하여 산정하였으며, 이 결과를 랜덤포레스트(Random Forest)에 학습함으로써 실시간 예측을 수행할 수 있도록 개발하였다. 침수범위 및 홍수위험등급에 대한 예측은 격자 단위로 이뤄졌으며, 검증 자료의 부족으로 침수 흔적도를 통하여 검증된 2차원 침수해석 결과와 비교함으로써 예측력을 평가하였다. 본 기법은 특정 관측강우 또는 예측강우 자료가 입력되었을 때에, 도시 유역 단위로 접근이 불가하여 통제해야 할 구간을 실시간으로 예측하여 관리할 수 있을 것으로 판단된다.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1744-1745
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• 2011

네트워크 기반 제어시스템에서 상위 제어시스템의 성능은 하부 네트워크 시스템의 성능에 의해 직접적으로 영향을 받는다. 따라서 네트워크 기반 빌딩자동제어 시스템 역시 하부 네트워크 시스템의 동작 및 성능에 의해 직접적으로 영향을 받는다. 본 연구에서는 빌딩자동제어시스템을 위한 데이터 통신 프로토콜로 개발되었으며, ISO에 의해 국제 표준 규격으로 제정된 BACnet의 하부 데이터링크 계층 프로토콜 중 필드레벨 네트워크 프로토콜로 가장 많이 적용되고 있는 BACnet MS/TP프로토콜 기반 네트워크 시스템의 성능을 실험적으로 해석하는 방법에 대해 소개한다.

• Proceedings of the KSR Conference
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• 2008.06a
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• pp.1794-1801
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• 2008

Fire-driven flow and temperature distribution in a ventilated tunnel was analyzed by Large Eddy Simulation using FDS code. The simulated tunnel is 182m length, 5.4m wide and 2.4m height. A pool fire was located 112m from tunnel entrance and was taken as a heat source of $0.89m^2$. The heat is assumed to be released uniformly throughout the whole simulated time. The fire strength was 2.76MW and the fuel burnt was octane. The parallel computational method was employed to accelerate the computing time and manage the large grid points which is not possible to handle in the one CPU. The total grid points used were $2.4{\times}10^6$ and 7 CPUs were used to calculate the momentum and energy equations. The simulated results were well compared with the experiments.

• Journal of the Korea Institute of Building Construction
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• v.17 no.1
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• pp.63-72
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• 2017

This research investigated the effect of solar radiation on the temperature distribution in concrete mat foundation. Zhang and Huang Model was utilized to estimate solar radiation heat at a given date and time. A one-dimensional finite element formula was derived with the fundamental laws of heat transfer and Galerkin method. Based on the formula, a one dimensional finite element analysis code was developed using MATLAB. Hydration heat analysis of mat foundation were conducted using the developed code. It was found that the solar radiation reduced the maximum temperature difference in mat foundation, and this temperature difference reduction was more prominent in case of summer season cast, a higher initial concrete temperature, and a thicker mat foundation depth. The research recommended that the solar radiation should be considered in hydration heat analysis of concrete mat foundation so as not to overestimate the maximum temperature difference in mat foundation.

• Journal of the Korea Concrete Institute
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• v.13 no.4
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• pp.389-396
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• 2001

This paper presents an analytical prediction of the fatigue behavior of reinforced concrete bridge piers under earthquake. Material nonlinearity is taken into account by comprising tensile, compressive and shear models of cracked concrete and a model of reinforcing steel. The smeared crack approach is incorporated. In boundary plane at which each member with different thickness is connected, local discontinuous deformation due to the abrupt change in their stiffness can be taken into account by introducing interface element. The effect of number of load reversals with the same displacement amplitude has been also taken into account to model the reinforcing steel. The proposed numerical method for fatigue behavior of reinforced concrete bridge piers under earthquake will be verified by comparison with reliable experimental results.

• Proceedings of the Korea Water Resources Association Conference
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• 2017.05a
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• pp.412-412
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• 2017

강우빈도해석을 위해서는 확률분포선정이 우선적으로 이루어져야 한다. 우리나라에서는 사용상의 편리상, 기존 해석결과와의 연속성 등을 이유로 Gumbel 확률분포가 가장 일반적으로 활용되고 있다. 그러나, 분포형 선정에 따른 확률강수량의 차이가 크게 발생한다는 점에서 단순히 해석상의 편리성을 기준으로 분포형 선정이 이루어지는 것은 바람직하지 않다. 특히, 우리나라에서 강우빈도해석 시 분포형 선정은 형식적인 수준에 그치고 있으며, 주로 KS검정, 검정 등 적합도 검정을 통해 고려된 분포형의 통계적 유의성만을 평가하고 있다. 그러나, 최적 분포형 선정이라는 관점에서 이러한 유의성 검정보다는 정량적인 지표를 기준으로 확률분포형 선정이 이루어지는 것이 적합할 것으로 판단된다. 즉, 자료의 설명력이 가장 우수한 분포를 정량적 지표를 기준으로 추정하는 것이 수문통계학적으로 적합성을 갖는다. 이러한 점에서 본 연구에서는 우도함수, BIC 및 AIC를 기준으로 우리나라 주요 강수지점에서 대해서 최적 분포형을 선정하고, 기존 Gumbel 분포를 기준으로 산정된 확률강수량과의 양적차이를 평가해보고자 한다.

• Journal of the Korean Geotechnical Society
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• v.26 no.3
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• pp.47-57
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• 2010

Yield seismic coefficient plays an important role in the estimation of permanent displacement of a soil slope subjected to earthquake using Newmark's sliding block theory. However, yield seismic coefficients currently used in practices are not mechanically rigorous since most of them are estimated using limit equilibrium methods considering equilibrium condition only. Therefore, estimation of permanent displacement of a soil slope based on existing yield seismic coefficient may cause problems. Limit analysis estimating the range of mechanically rigorous solution is thought to be effective in evaluating the validity of existing yield seismic coefficient. In this study, a simple stability chart for yield seismic coefficient useful in practices is proposed by considering various slope conditions including stability number, slope inclination, strength parameters, etc.

• Journal of the Society of Naval Architects of Korea
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• v.30 no.4
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• pp.136-152
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• 1993

This study is intended to develop an accurate and efficient, analytical thin-walled beam model, and to analyze overall behavior of SWATH ship under repeated overloads. SWATH ship is idealized to a simple thin-walled beam of channel type. An analytical beam model is formulated by the stress component with geometrically(fully) nonlinear thin-walled beam and treated numerically by the Finite Element Method. An efficient cyclic plasticity model is also included, suitable for material nonlinear behavior under complex loading conditions. The local stress distribution can be very exactly represented and the material yielding propagation, easily traced. In addition, the local treatment of the effect of shear deformation improves the representation of deformation and shear stress distribution along the section contour. It is desirable to use the analytical thin-walled beam at initial design stage, and is needed to improve the practical thin-walled beam model advancing the current approach.

• Korean Journal of Social Welfare Studies
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• v.42 no.2
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• pp.41-70
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• 2011

This research is to study the interaction of multiculture parents in law between. daughter in law. We approached hermeneutical grounded theory and six of multiculture family's parent's in law participated this research. Data were collected by the depth interview and various written records and we could construct 9 hermeutical theme by analyzing and categorizing 83 meaning units, 22 categories. We descripted the process of acculturation between parent's in law and daughter in law. The result as follows : ① sticking self dimensions → ② strategic acceptomce → ③ making shade of co-existence → ④ self dismantling and reconstruction. Finally we proposed the 「joint program of parent's in law and daughter in law for reinforcing culture unpetence」.

• Magazine of the Korea Concrete Institute
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• v.8 no.4
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• pp.191-199
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• 1996

Cracks occur in mass concrete structures during construction if temperature of the concrete due to heat of hydration is suddenly changed. The temperature is also changed after placement of mass concrete by construction environments on structures. However, methods which can analyze the temperature history of mass concrete considering the construction environments have not been developed yet. In this research, an algorithm and finite element analysis program is developed for the analysis of temperature rise history of mass concrete considering quantitatively heat transfer coefficient and construction environmental conditions such as climate conditions, curing conditions, forms and form removal, and additive curing. By comparing analysis results of the program with experimental data, other research data, and analysis results by a finite element program ADINAT, validity and accuracy of the program is verified.