• Korean Journal of Agricultural and Forest Meteorology
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• v.15 no.1
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• pp.17-25
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• 2013

In this paper we interpreted the changes in wind field over complex mountainous terrains. The results of our study can be applied for predicting the direction of fire spread and for establishing strategies for fire prevention. The study area is bounded by $12{\times}12$ km domains of the Samcheok's long-term ecological research (LTER) site located in the east coast, in which a large-fire had occurred from 7 to 13 April 2000. Because of the area's complex topography, we compared the result of the Weather Research and Forecasting (WRF) mesoscale model with those observed by four automated weather stations. The WRF simulation overestimated the wind speed by 5 to 8 m/s (~200%) in comparison with those from four automated weather stations. The wind directions observed by the AWSs were from various directions whereas those from WRF model were mostly west wind at all stations. Overall, the simulations by the WRF mesoscale models were not appropriate for the estimation of microscale wind fields over complex mountainous areas. To overcome such inadequacy of reproducing the wind fields, we employed the ENVI-met model over Samcheok's LTER site. In order to test the model's sensitivity with the terrain effects, experimental simulations were conducted with various initial conditions. The simulation results of the ENVI-met model showed a reasonable agreement in wind speeds (about 70% accuracy) with those of the four AWSs. Also, that the variations in wind directions agreed reasonably well with changes in terrain effect. We concluded that the ENVI-met model is more appropriate in representing the microscale wind field over complex mountain terrains, which is required to predict fire spread and to establish strategies for forest fire prevention.

• Journal of Korea Society of Industrial Information Systems
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• v.22 no.2
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• pp.79-89
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• 2017

The Optimization of a Closed-Loop Supply Chain (CLSC) Model Using an Adaptive Hybrid Genetic Algorithm (AHGA) Approach is Considered in this Paper. With Forward and Reverse Logistics as an Integrated Logistics Concept, The CLSC Model is Consisted of Various Facilities Such as Part Supplier, Product Manufacturer, Collection Center, Recovery Center, etc. A Mathematical Model and the AHGA Approach are Used for Representing and Implementing the CLSC Model, Respectively. Several Conventional Approaches Including the AHGA Approach are Used for Comparing their Performances in Numerical Experiment.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.439-439
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• 2018

충주호는 충청권의 생 공 농업용수로 이용되는 광역상수원이며, 2016년 기준 연간 약 3만6천톤이 방류되어 남한강 전체 수질에 큰 영향을 미친다. 현재 충주호는 상류 유역의 오염원이 적게 분포하여 1급수의 수질기준을 만족하고 있으나, 상류 유역의 개발로 오염원 유입이 증가할 경우 호소 내 수질 및 남한강 전체 수질에 악영향을 미칠 수 있다. 따라서 충주댐 상류 유역의 오염부 하량 변화에 따른 수질변화를 예측하고, 현재수질 유지를 위한 허용 오염부하량을 산정할 필요가 있다. 한편, EFDC-WASP 연계모델은 수리학적 계산을 보다 정확하게 할 수 있는 동시에 이를 수질모델에 사용할 수 있어 다수의 연구자들에 의해 호소의 수질 모델링이 이루어졌으며 적용성이 많이 검증되었다. 본 연구에서는 EFDC-WASP 연계 모형을 이용하여 충주댐 상류유역의 배출부하 변화에 따른 호내 수질특성 변화를 분석하고자 한다. 모의구간은 충주댐의 유입지점부터 방류지점까지로, 수치해석을 위한 격자망은 총 800여개의 격자로 구성하였다. 수위자료는 한강홍수통제소에서 제공하는 충주댐 수위자료를 사용하였으며, 수질자료는 환경부 호소 측정지점인 충주호1,2,3 의 자료와 하천 측정지점인 제천A과 한강B의 자료를 사용하였다. 모의기간은 2013-2015년으로 2013년은 모델의 안정기로, 2014년은 보정, 2015년은 검정에 각각 활용하였다. 보검정된 모델을 활용하여 유입부하량 변화에 따른 수질변화를 모의하였고, 1급수 수질을 만족하는 허용부하량을 도출하였다. 본 연구의 방법은 향후 호소 상류유역의 개발에 따른 수질변화 예측과 허용부하량 산정에 활용할 수 있을 것으로 기대된다.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.2 s.40
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• pp.3-14
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• 2007

This study proposes an automatic method to generate 3D building models using a draft map, which is an intermediate product generated during the map generation process based on aerial photos. The proposed method is to generate a terrain model, roof models, and wall models sequentially from the limited 3D information extracted from an existing draft map. Based on the planar fitting error of the roof corner points, the roof model is generated as a single planar facet or a multiple planar structure. The first type is derived using a robust estimation method while the second type is constructed through segmentation and merging based on a triangular irregular network. Each edge of this roof model is then projected to the terrain model to create a wall facet. The experimental results from its application to real data indicates that the building models of various shapes in wide areas are successfully generated. The proposed method is evaluated to be an cost and time effective method since it utilizes the existing data.

• Journal of the Korean GEO-environmental Society
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• v.13 no.2
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• pp.103-112
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• 2012

The most of original horizontal bearing capacity theory of the pile is not efficiently to consider interaction between soil and pile because it is only to consider the earth pressure theory and separately the ground form pile. In recent, in order to improve the pile technology, it is necessary to confirm the real behaviour characteristics of pile under lateral load. Hence, to evaluate the behaviour characteristics of the single and group pile under lateral loads using the strain wedge model that could consider the interaction between soil and piles. Primarily, laboratory scale down model tests was carried out to predict the behaviour characteristics on real size piles using the strain wedge model. The comparative analyses between model test and numerical analysis for the evaluation of whole behaviour were conducted.

• Water for future
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• v.26 no.2
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• pp.39-48
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• 1993

Since major reason of disaster in coastal area is wave action, prediction of wave deformation is one of the most important problems to ocean engineers. Wave deformations are due to physical factors such as shoaling effect, reflection, diffraction, refraction, scattering and radiation etc. Recently, numerical models are widely utilized to calculate wave deformation. In this study, the mild slope equation was used in calculatin gwave deformation which considers diffraction and refraction. In order to slove the governing equation, finite element method is introduced. Even though this method has some difficulties, it is proved to predict the wave deformation accurately even in complicated boundary conditions. To verify the validity of the numerical calculation, experiments were carried out in a model harbour of rectangular shape which has mild slope bottom. The results by F.E.M. are compared with those of both Lee's method and the experiment. The results of these three methods show reasonable agreement.

• Geophysics and Geophysical Exploration
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• v.6 no.4
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• pp.165-170
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• 2003

Recently, resistivity surveys have been frequently carried out over the irregular terrain such as mountainous area. Such an irregular terrain itself can produce significant anomalies which may lead to misinterpretations. In this study, topographic effects in resistivity survey were studied using the physical scale modeling as well as the numerical one adopting finite element method. The scale modeling was conducted at a pond, so that we could avoid the edge effect, the inherent problem of the scale modeling conducted in a water tank in laboratory. The modeling experiments for two topographic features, a ridge and a valley with various slope angles, confirmed that the results by the two different modeling techniques coincide with each other fairly well for all the terrain models. These experiments adopting dipole-dipole array showed the distinctive terrain effects, such that a ridge produces a high apparent resistivity anomaly at the ridge center flanked by zones of lower apparent resistivity. On the other hand, a valley produces the opposite anomaly pattern, a central low flanked by highs. As the slope of a terrain model becomes steeper, the terrain-induced anomalies become stronger, and moreover, apparent resistivity can become even negative for the model with extremely high slope angle. All the modeling results led us to the conclusion that terrain effects should be included in the numerical modeling and/or the inversion process to interpret data acquired at the rugged terrain area.

• Journal of the Korean Geotechnical Society
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• v.29 no.4
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• pp.23-32
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• 2013

In order to evaluate the bearing capacity behaviour of a monopod suction bucket foundation for an offshore wind tower at the western sea of Korea, a centrifuge load test and numerical analyses were performed. The monopod bucket foundation was designed to be installed in a silty sand layer. The model soil was prepared to simulate a target site by using soil samples having similar properties and controlling relative density. In-flight miniature cone penetration test and bender element array were used to confirm that the model soil had represented the target site conditions. The load - rotation curve of the centrifuge load test was analysed. A series of numerical analyses were performed to validate the experimental conditions. Self-weight of the model, distance to the boundary and elastic modulus of the soil layer were varied to study their effects on the load - rotation curves.

• Proceedings of the KIEE Conference
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• 2008.07a
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• pp.1991-1992
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• 2008

경두개자기자극술(Transcranial Magnetic Sitmulation:이하 TMS)은 두뇌 외부에 설치된 코일을 이용하여 짧은 시간에 강한 펄스 형태의 자기장을 인가하여 두뇌 내부에 유도전기장을 발생시켜 특정 부위의 신경조직을 자극하는 비침습적(noninvasive)인 기술이다. 두뇌 내부에 정확한 자극 분포와 자극 세기를 알기 위해 Zubal Data에 근거한 정밀한 두뇌형상모델을 이용하여 비균질성을 고려해 수치해석을 하였다. 수치해석 결과 복잡한 머리 내부에 유기되는 정확한 유도전기장 분포를 예측하였고 실험을 통해 수치해석의 유효성을 증명하였다.

• The Korean Journal of Applied Statistics
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• v.21 no.4
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• pp.705-716
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• 2008

The objectives of this study are the detection and forecast of climate change signal in the annual mean of surface temperature data, which are generated by MRI/JMA CGCM over the Korean Peninsula. MRI/JMA CGCM outputs consist of control run data(experiment with no change of $CO_2$ concentration) and scenario run data($CO_2$ 1%/year increase experiment to quadrupling) during 142 years for surface temperature and precipitation. And ECMWF reanalysis data during 43 years are used as observations. All data have the same spatial structure which consists of 42 grid points. Two statistical models, the Bayesian fingerprint method and the regression model with autoregressive error(AUTOREG model), are separately applied to detect the climate change signal. The forecasts up to 2100 are generated by the estimated AUTOREG model only for detected grid points.