• Korean Journal of Hydrosciences
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• 제5권
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• pp.57-70
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• 1994

For the system benefit optimization by considering risk or reliability from a multiple reservoir system using the Monte Carlo Technique, Many stochastically generated inflow series have to be used for the system analysis. In this study, the stochastically generated inflow series for the multiple reservoir system operation are preprocessed according to the considering system objectives and operating time periods. Through this procedure, several representative inflow series which have discrate probability levels and operation horizons are selected among the thousands of generated inflows. Then a deterministic optimization technique is applied to the hydropower energy estimation from the Han River Reservoir System which considers five reservoirs in this study. It took much less computational requirements than using the original Morite Carlo Technique, even though estimated result was almost similar.

• 수산해양기술연구
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• 제60권1호
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• pp.27-36
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• 2024

The towing distance, which is speed over the ground, and the water flow quantity, which is speed through the water, were used when estimating the amount of Metapenaeus joyneri resources that rose to the surface at night using the swept area method in order to compare and analyze the difference. It was conducted using a shrimp dredge, trial fishing gear for catching Metapenaeus joyneri. Catch during the entire survey period was 188.9 kg. Monthly catch ranged from 3.1 to 109.2 kg, highest in June and lowest in September. The swept volume calculated using the speed over the ground was about 13% higher than using the speed through the water. Metapenaeus joyneri resources estimated using the towing distance ranged from 320.1 to 14,649.8 kg. Resources estimated using the water flow quantity ranged from 278.5 to 12,886.3 kg. Therefore, the amount of Metapenaeus joyneri resources estimated using the speed over the ground was about 14% higher than the method using the speed through the water, indicating that the amount of resources was overestimated.

• 한국수자원학회논문집
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• 제37권12호
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• pp.993-1007
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• 2004

허스트 지수를 산정하기 위하여 기존에 여러 방법론들이 제안되어 왔다. 그러나, 이들 방법론들은 시계열들의 지속성에 대하여 각기 다른 특성들을 보이고 있음을 기존의 연구에서 알 수 있다 따라서 본 연구에서는 수문학에서 주로 이용하고 있는 보정용량, 조정용량, 수정조정용량 방법 이외에 생리학 분야와 전자 분야 등에서 이용되고 있는 1/f 파워 스펙트럼 밀도 분석, DFA, AVT 방법, 최우도법 등을 이용하여 허스트 지수를 산정하여 보았다. 즉, 단기간과 장기간 기억을 가진 카오스와 추계학적 시계열들에 대하여 각각의 방법들을 적용하여 비교 분석하고자 하였으며, 각 방법론들에 대한 장점 및 단점 그리고 한계에 대하여 논의하였다.

• 한국수자원학회논문집
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• 제36권6호
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• pp.985-997
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• 2003

본 연구의 목적은 미국 토양보존국(SCS)의 피복분류에 따른 유출곡선지수(CN) 값을 이용하여 위성영상 피복분류 항목에 대한 CN 값을 제시하는데 있다. 이를 위하여 SCS의 각 피복항목별 정의와 유역의 CN값 산정 방법에 대해서 연구하였다. 위성영상 피복분류 항목에 대한 CN값 산정방법으로 통계적 접근법을 사용하였으며 공간해상도에 따라 대분류, 중분류, 세분류로 구분된 환경부의 위성영상 피복분류항목에 대한 CN 값을 산정하였다. 본 연구의 결과는 향후 위성영상을 이용하여 CN 값을 산정할 경우 효율적으로 사용될 것으로 판단된다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권2호
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• pp.198-208
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• 2016

The painting process of large ships is an intense manual operation that typically comprises 9-12% of the total shipbuilding cost. Accordingly, shipbuilders need to estimate the required amount of anti-corrosive coatings and painting resources for inventory and cost control. This study aims to develop a software system which enables the shipbuilders to estimate paint area using existing 3D CAD ship structural models. The geometric information of the ships structure are extracted from the existing shipbuilding CAD/CAM system and used to create painting zones. After specifying the painting zones, users can generate the paint faces by clipping structural parts inside each zone. Finally, the paint resources may be obtained from the product of the paint areas and required paint thickness. Implementing the developed software system to real shipbuilders' operations has contributed to improved productivity, faster resource estimation, better accuracy, and fewer coating defects over their conventional manual calculation methods for painting resource estimation.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2008년도 학술발표회 논문집
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• pp.805-809
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• 2008

Measurement of leaf area index (LAI) is useful for understanding rice growth, water use, and canopy light interception. The top nitrogen content(TNC) per unit area is an important quantitative index of the condition of nitrogen nutrition in rice production. The rapid and simple method of estimation of TNC, with the use of the existing nondestructive analyzing instruments chlorophyll meter SPAD-502 and plant canopy analyzer (PCA) LAI-2000, was scrutinized. Destructive measurement is time consuming and labor intensive. Our objective was to evaluate sampling procedures using the Li-Cor LI-1800, LAI 2000 plant canopy analyzer (PCA) for nondestructive estimation of rice LAI, and SPAD-502 on the Northern Plains of Cheongju. The LAI estimated by PCA tended to underestimate the LAI determined by actual measurement by about 20%. The estimation of LAI by PCA was judged to have a sufficient accuracy as a practical technique. A high positive correlation was obtained between the values of the SPAD reading and LAI. NDVI and LAI also showed a very high correlation. The values of the SPAD reading and LAI, and NDVI gave a high positive correlation. These results indicated that the method described in this study was effective as a simple and rapid method for the estimation of rice growth.

• 대한원격탐사학회지
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• 제27권3호
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• pp.389-401
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• 2011

Most nations around the world have expressed significant concern in the climate change due to a rapid increase in green-house gases and thus reach an international agreement to control total amount of these gases for the mitigation of global warming. As the most important absorber of carbon dioxide, one of major green-house gases, forest resources should be more tightly managed with a means to measure their total amount, forest biomass, efficiently and accurately. Forest biomass has close relations with forest areas and tree height. Airborne LiDAR data helps extract biophysical properties on forest resources such as tree height more efficiently by providing detailed spatial information about the wide-range ground surface. Many researchers have thus developed various methods to estimate tree height using LiDAR data, which retain different performance and characteristics depending on forest environment and data characteristics. In this study, we attempted to investigate such various techniques to estimate tree height, elaborate their advantages and limitations, and suggest future research directions. We first examined the characteristics of LiDAR data applied to forest studies and then analyzed methods on filtering, a precedent procedure for tree height estimation. Regarding the methods for tree height estimation, we classified them into two categories: individual tree-based and regression-based method and described the representative methods under each category with a summary of their analysis results. Finally, we reviewed techniques regarding data fusion between LiDAR and other remote sensing data for future work.

• 한국수자원학회논문집
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• 제32권4호
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• pp.437-445
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• 1999

비모수능형회귀분석법을 이용하여 수문응답을 추정하는 방안에 대하여 연구하였다. 응답을 추정하기 위하여 평균제곱예측오차에 대한 추정량인 CL 통계량을 최소화하는 방법을 적용하였으며 가중행렬은 전통적으로 이용도는 단위행렬과 특수한 형태인 행렬인 Laplacian 행렬을 각각 이용하여 비교하였다. 또한 추정응답의 오차분산을 추정하는 방안에 대한 검토도 실행하였다. 합성자료와 실제자료에 대한 분석 결과 가중행렬과 Laplacian 행렬을 오차분산은 편기 수정된 추정치를 이용하는 것이 좋은 결과를 보여 주었다. 본 연구에서 제시된 절차 및 방법은 수문응답 분리에 있어서 안정적이고 효율적으로 적용될 수 있을 것으로 판단된다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2019년도 학술발표회
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• pp.164-175
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• 2019

The Tor Tong Daeng Irrigation Project with the irrigation area of 61,400 hectares is located in the Ping Basin of the Upper Central Plain of Thailand where farmers depended on both surface water and groundwater. In the drought year, water storage in the Bhumipol Dam is inadequate to allocate water for agriculture, and caused water deficit in many irrigation projects. Farmers need to find extra sources of water such as water from farm pond or groundwater as a supplement. The operation of Bhumipol Dam and irrigation demand estimation are vital for irrigation water allocation to help solve water shortage issue in the irrigation project. The study aims to determine the smart dam operation system to mitigate water shortage in this irrigation project via introduction of machine learning to improve dam operation and irrigation demand estimation via soil moisture estimation from satellite images. Via ANN technique application, the inflows to the dam are generated from the upstream rain gauge stations using past 10 years daily rainfall data. The input vectors for ANN model are identified base on regression and principal component analysis. The structure of ANN (length of training data, the type of activation functions, the number of hidden nodes and training methods) is determined from the statistics performance between measurements and ANN outputs. On the other hands, the irrigation demand will be estimated by using satellite images, LANDSAT. The Enhanced Vegetation Index (EVI) and Temperature Vegetation Dryness Index (TVDI) values are estimated from the plant growth stage and soil moisture. The values are calibrated and verified with the field plant growth stages and soil moisture data in the year 2017-2018. The irrigation demand in the irrigation project is then estimated from the plant growth stage and soil moisture in the area. With the estimated dam inflow and irrigation demand, the dam operation will manage the water release in the better manner compared with the past operational data. The results show how smart system concept was applied and improve dam operation by using inflow estimation from ANN technique combining with irrigation demand estimation from satellite images when compared with the past operation data which is an initial step to develop the smart dam operation system in Thailand.

• 한국지역사회생활과학회:학술대회논문집
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• 한국지역사회생활과학회 2005년도 춘계학술대회 자료집
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• pp.176-176
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• 2005