• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.490-491
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• 2012

본 논문에서는 가변속 풍력발전시스템을 위한 최적속도의 PSF(Power Signal Feedback) MPPT 제어를 제안한다. 풍속센서를 이용한 데이터 수집이 요구되지 않으며 공기밀도, 출력되는 전력 피드백 값을 이용하여 시스템 속도 제어를 위한 지령속도를 출력하여 최대 전력점을 찾도록 하는 제어 방법으로, PSIM 프로그램 결과를 통해 본 논문의 타당성을 입증한다.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.37 no.2
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• pp.445-449
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• 2017

Most studies using drone is confined utilization on the ground and regulation. The drone in the water is rarely used in hydrographic surveying because of the limit of flight time and image matching. This paper is the basic research for drone hydrographic photogrammetry. The accuracy of hydrographic photogrammetry, using buoys for water reference point, was evaluated. The accuracy is influenced by the accuracy of the water reference points like the photogrammetry. The position of water reference points set up on water, keep on changing due to various environmental factors such as wind speed and water velocity. The position continuously changed of the water reference points were measured 3 times using Total Station and VRS. Experiments were conducted at two reservoirs in Gimhae City, and the accuracy of the manual image matching using the water reference points is 40 cm and 80 cm. Allowable accuracy of the ocean boundary survey is ${\pm}2m$, the results of this study are fully available. The maximum position error of the water reference point for ensuring accuracy within ${\pm}2m$ is 1.8 m.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.27 no.3
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• pp.168-174
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• 2015

Characteristics of high waves occurred in winter season on the west coast of Korea were investigated by analyzing the wave data observed at five observation locations. Records of four different high waves were subjected to the analysis together with the corresponding meteorological data during those time periods. The significant wave height reached its maximum of 6.42 m on December 4th, 2005. It was clarified that the high waves occurred due to strong wind fields that were formed over the west sea of Korea when the extra-tropical cyclone was excessively developed. Characteristics of the high waves generated in the west sea seemed to be predominantly wind sea as the temporal variation of the wave height at the coast were closely related to those of the wind speed measured at neighboring weather stations.

• Journal of the Korean earth science society
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• v.42 no.5
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• pp.536-555
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• 2021

Sea-surface wind is an important variable in ocean-atmosphere interactions, leading to the changes in ocean surface currents and circulation, mixed layers, and heat flux. With the development of satellite technology, sea-surface winds data retrieved from scatterometer observation data have been used for various purposes. In a complex marine environment such as the Korean Peninsula coast, scatterometer-observed sea-surface wind is an important factor for analyzing ocean and atmospheric phenomena. Therefore, the validation results of wind accuracy can be used for diverse applications. In this study, the sea-surface winds derived from ASCAT (Advanced SCATterometer) mounted on MetOp-A/B (METeorological Operational Satellite-A/B) were validated compared to in-situ wind measurements at 16 marine buoy stations around the Korean Peninsula from January to December 2020. The buoy winds measured at a height of 4-5 m from the sea surface were converted to 10-m neutral winds using the LKB (Liu-Katsaros-Businger) model. The matchup procedure produced 5,544 and 10,051 collocation points for MetOp-A and MetOp-B, respectively. The root mean square errors (RMSE) were 1.36 and 1.28 m s^-1, and bias errors amounted to 0.44 and 0.65 m s^-1 for MetOp-A and MetOp-B, respectively. The wind directions of both scatterometers exhibited negative biases of -8.03° and -6.97° and RMSE values of 32.46° and 36.06° for MetOp-A and MetOp-B, respectively. These errors were likely associated with the stratification and dynamics of the marine-atmospheric boundary layer. In the seas around the Korean Peninsula, the sea-surface winds of the ASCAT tended to be more overestimated than the in-situ wind speeds, particularly at weak wind speeds. In addition, the closer the distance from the coast, the more the amplification of error. The present results could contribute to the development of a prediction model as improved input data and the understanding of air-sea interaction and impact of typhoons in the coastal regions around the Korean Peninsula.

• Environmental and Resource Economics Review
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• v.15 no.2
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• pp.269-296
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• 2006

With the concern of the potential problems which can be observed in terms of the power supply of renewable energies, we need to analyze the impact of additional power generation capacities of renewable energy sources on peak load. Each renewable energy sources are dependent upon wind speed, solar radiation, head differences caused by lunar calendar. Considering that these exogenous renewable energy sources follow their own stochastic distributions, we analyze the probability distribution of the impact of each renewable energy power supply on peak load. As a conclusion, we note that traditional tools used for the analysis of power supply such as capacity factors are no longer appropriate for the analysis of renewable energy sources in that perspective.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.1
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• pp.71-78
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• 2016

This paper proposes the new electric power demand forecast model which is based on an artificial neural network and considers time and weather factors. Time factors are selected by measuring the autocorrelation coefficients of load demand in summer and winter seasons. Weather factors are selected by using Pearson correlation coefficient The important weather factors are temperature and dew point because the correlation coefficients between these factors and load demand are much higher than those of the other factors such as humidities, air pressures and wind speeds. The experimental results show that the proposed model using time and seasonal weather factors improves the load demand forecasts to a great extent.

• Proceedings of the Korea Water Resources Association Conference
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• 2019.05a
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• pp.29-29
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• 2019

급격한 도시화와 기후변화로 인한 자연적인 물순환 구조의 변화는 기존 수자원 이용 경향을 변화시키며 하천건천화 현상을 유발하고 있다. 이를 관리하기 위해 하천건천화 평가 및 예측이 가능한 영향 평가 기술이 필요하며, 국내에서는 GIS 기반의 분포형 수문 모형인 Drying Stream Assessment Tool and Water Flow Tracking (DrySAT-WFT)이 개발되어 활용되고 있다. 그러나 격자기반의 물수지 모형은 단위 cell 안의 수직적인 물의 거동은 파악하기 용이하나, 모형의 특성상 저수지, 댐, 보와 같은 수리 시설물의 방류량에 따른 하도의 흐름 추적에는 어려움이 있다. 본 연구의 목적은 DrySAT-WFT 모형에 댐?보 방류량 자료와 연계한 하도추적 알고리즘을 개발하여 모형의 유출 모의 성능을 개선하고, 1976년부터 2015년까지의 유출 모의를 통해 전국 표준유역을 대상으로 각 유역에 대한 하천건천화 원인 추적 및 평가를 수행하고자 한다. 하천건천화영향요소를 고려하기 위한 모형의 입력 자료로 산림높이, 도로망, 지하수 이용량, 토지이용, 토심, 기상 변화에 대해 1976년부터 2015년까지 구축한 시계열 전국 자료를 활용하였으며, 일별 강우량, 상대습도, 평균풍속, 평균 및 최고, 최저 기온, 일조시간의 기상자료를 구축하였다. 개선된 DrySAT-WFT 유출 모의 결과는 선행 연구와의 비교를 통해 모의 개선점을 정량적으로 제시하고자 한다.

• Archives of design research
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• v.19 no.5 s.67
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• pp.151-160
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• 2006

When it comes to the paintings in Joseon Dynasty, landscape and a genre paintings were popular but it was Minhwa that people of every dass loved. Minhwa contained not only true meaning of a picture, but also it was simple and straighforwardly depicted. Among them, paintings in books belonging to the Joseon Dynasty (hereinafter called Checkgeori paintings) describe a small universe in which people live harmoniously in nature on the basis of a Confucian society. In addition, it shows modern philosophy in paintings and makes a feature of human life. In this paper, 'Ssangpok Checkgeori 'in Checkgeori paintings illustrates the relationships between things such as color, arrangement, place and direction. They have outstanding features such as the direction of things in composition, multiple vanishing points, a folding screen constituent and movement of viewpoints. Therefore, we come to know the painting method of 'Ssangpok Checkgeori' can be applied to modern paintings.

• The Journal of the Korea Contents Association
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• v.18 no.7
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• pp.656-664
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• 2018

The following study was conducted to determine the optimal location in terms of efficiency for solar energy facilities, and to propose a policy implications for the orientation of the installments. 92 cases in Jeollanam-do Province were selected. A regression analysis was performed between the average electricity generation time as the dependent variable, and the facility, weather and site conditions as the independent variables. As a result, 5 variables were deemed significant. Larger site areas, closer proximity to rivers, islands, oceans, etc., least south-oriented, higher average wind speed, and facilities in agricultural land use and natural environment conservation land use had the highest efficiency. This study minimized the possibility of secure databases and errors following facility types, and was limited in the number of sites studied, since this was only conducted in Jeollanam-do Province. Nevertheless, these conclusions still offer important policy implications for determining the most optimal location for solar energy facilities.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• v.2
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• pp.143-147
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• 2006

The rail clamp is the device to prevent that a crane slips along rails due to the wind blast as well as locate the crane in the set position for loading and unloading containers. The wedge type rail clamp should be designed to consider the structural stability and the durability because it compresses both rail side with large clamping force by the wedge working as the wind speed increases. In this research, the kriging interpolation method using sequential sampling is utilized to find the optimum shape of the jaw in the rail clamp. The suggested method predicts more accurate response value than the response surface method. The optimum results obtained by the proposal method are compared with those by the commercial software.