• Proceedings of the Computational Structural Engineering Institute Conference
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• 2010.04a
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• pp.488-491
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• 2010

본 논문에서는 돌풍응답경감제어 효과 검증을 위한 풍동시험에 사용될 유연날개에 대해 공탄성 모델, 조종면 작동기 모델, 돌풍 모델 등으로 구성되는 서보공탄성 모델링을 수행하였으며, 이에 대한 연속돌풍 응답해석을 수행하여 상용 Solver를 이용한 해석결과와 비교하여 구성된 서보공탄성 모델을 검증하였다. 또한, 유연날개의 돌풍응답을 경감하는 조종면 제어기를 설계하고, 이에 대한 수치 시뮬레이션을 수행하여 돌풍응답 경감효과를 검증하였다.

• Journal of Environmental Science International
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• v.11 no.3
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• pp.161-168
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• 2002

This study was carried out for reading the change of local meteorological environment according to dam construction of Nakdong-river using meteorological data analysis, and modeling. The meteorological data analysised are mean temperature, foggy day, precipittion day and sunshine time. As tile result of analyzing meteorological data of before and after the construction of dam in Andong and Hapchon, some discrepancy were observed by month because the lakes have different effect on the region as wind field. The common phenomenons that are revealed after dam construction are increase of foggy day and decrease of sunshine time.

• Journal of the Korean Society of Safety
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• v.31 no.3
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• pp.162-167
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• 2016

As the simple empirical and phenomenological model applied to the analysis of leakage and explosion of chemical substances does not regard numerous variables, such as positional density of installations and equipment, turbulence, atmospheric conditions, obstacles, and wind effects, there is a significant gap between actual accident consequence and computation. Therefore, the risk management of a chemical plant based on such a computation surely has low reliability. Since a process plant is required to have outcomes more similar to the actual outcomes to secure highly reliable safety, this study was designed to apply the CFD (computational fluid dynamics) simulation technique to analyze a virtual prediction under numerous variables of leakages and explosions very similarly to reality, in order to review the computation technique of the practical safety distance at a process plant.

• International Journal of Aeronautical and Space Sciences
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• v.13 no.1
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• pp.74-89
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• 2012

An adaptive backstepping controller is designed for the automatic landing of a fixed-wing aircraft. The backstepping control scheme is adopted by using the nonlinear six degree-of-freedom dynamics of the aircraft during the landing phase. The adaptive law is integrated along with the backstepping controller in order to estimate the aircraft modeling errors as well as the external disturbance. The dynamic constraints of the states and the actuator inputs are taken into account in the parameter adaptation. This is done to prevent an aggressive adaptation and to provide reliable control commands. Numerical simulations were performed to verify the performance of the proposed control law for the landing of the aircraft with the presence of gust and actuator stuck.

• Proceedings of the KIPE Conference
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• 2008.10a
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• pp.193-195
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• 2008

As arising the cost and decreasing of gasoline and fossil fuel, renewable energy sources such as photovoltaics, wind and fuel cell have been interested. Among of them, PEM fuel cells are good energy sources to provide reliable power at steady state regardless of weather, time of day and location as long as the fuel and air are supplied, but they cannot respond to electrical load transients as fast as desired. This is mainly due to their slow internal electrochemical and thermodynamic responses. Therefore, to use the fuel cells with high efficiency, this paper finds characteristic curve and understand operation of PEMFC based on three theoretical approaches such as activation, ohmic and concentration and make the model using MATLAB. That result was compared with real system to certify.

• Proceedings of the KIPE Conference
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• 2014.07a
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• pp.455-456
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• 2014

본 논문에서는 인버터 스위치의 PWM 펄스 전압에 의해 발생하는 발전기 단자의 과전압 현상을 해석하기 위해, 전력 케이블과 발전기의 고주파 모델링을 제시하고, 이에 의한 과전압 현상을 해석한다. 또한, 이 과전압 현상을 억제하기 위한 적절한 형태의 인버터 출력단 dv/dt 필터를 설계하고, 선정된 dv/dt 필터 토폴로지의 필터 파라미터의 범위를 제시한다.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.598-603
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• 2002

We summarize the activities concerning to the space-borne microwave radiometer (RAD) calibration and validation (Cal/Val) in China. It is important to know in advance the brightness temperature of a given sea surface before external calibrating RAD due to its special characteristic of system. In the paper, we analyse some modeling results on sea surface emissivity and atmospheric transmissivity at different frequencies, and compare the calculated brightness temperatures with those measurements from some air-borne microwave radiometers. We also introduced the whole contents on RAD Val and developed two methods of retrieving sea surface winds. We compared the retrievals of wind speeds to those from NDBC buoys. At last, we introduce some plans of Cal/Val for testing our RAD.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1340-1342
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• 2003

In microwave remote sensing, the Fresnel reflectance formula is widely used in the sea surface emissivity modeling. As an essential contribution to microwave remote sensing, a new formula on the Fresnel reflectance has been derived based on our understanding of the complex index of refraction and continuity condition of E-M waves at the interface between two mediums. The proposed formula can be used to obtain the emissivity of sea surface, which is useful to retrieve sea surface temperature, sea surface salinity and the brightness temperature. Considering Bragg-resonant scatter, it is useful for the calculation of the normalized radar cross-section, and the retrieval of sea surface wind either.

• KEPCO Journal on Electric Power and Energy
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• v.5 no.3
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• pp.223-228
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• 2019

In order to integrate large amounts of variable generation resources such as wind and solar reliably into power grids, accurate renewable energy forecasting is necessary. Since renewable energy generation output is heavily influenced by environmental variables, accurate forecasting of power generation requires meteorological data at the point where the plant is located. Therefore, a spatial approach is required to predict the meteorological variables at the interesting points. In this paper, we propose the meteorological variable prediction model for enhancing renewable generation output forecasting model. The proposed model is implemented by three geostatistical techniques: Ordinary kriging, Universal kriging and Co-kriging.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.17 no.4
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• pp.336-341
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• 1988

바람은 건물 외벽에서의 압력차의 주요인의 하나이다. 바람에 의한 압력차를 정확히 예측할 수 있다는 것은 외벽에 있어서의 풍하중, 건물내로 투입되는 공기양의 설계치 결정, 그리고 건물을 사용하는 거주인의 병리학적 면에서 보다 중요한 것이다. 단열재로 잘 설계된 건물에서는 투입되는 공기에 의한 열부하가 전체 열부하의 30 ~ 50%도 될 수 있으며, 화재시 화염과 연기의 확산에도 중요한 문제이다. 20층 아파트를 사용해서 실물실험을 한 후 측정된 여러가지 값을 예측할 수 있는 방법을 고찰했으며 본 연구에서는 건물에서 바람에 기인되는 압력차를 예측하는 modeling과 Simulation에 있어서의 고찰할 여러가지 재원을 제시했다. 또한 Model을 이용한 실험결과는 Simulation에 있어서 적합한 조건을 충족시키면 풍동을 사용하여 바람에 기인하는 압력차를 예측할 수 있다는 것이 증명되었다.