• Proceedings of the Korea Water Resources Association Conference
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• 2011.05a
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• pp.127-127
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• 2011

본 연구에서는 RHESSys (Regional Hydro-Ecologic Simulation System) 모형을 이용하여 산림 유역의 생태수문학적 거동을 평가하고자 한다. 설마천 유역($8.48\;km^2$)을 대상으로 2007~2009년의 관측 일유출량을 이용하여 유출량을 검 보정하였고, 증발산량 및 토양수분은 신뢰할 만한 실측자료를 바탕으로 모형의 보정(2007-2008)및 검증(2009)을 실시하였다. 또한 지구의 탄소순환을 규명할 수 있는 식생의 순광합성량과 총일차생산량에 대한 모형의 검 보정은 Terra 위성의 MODIS (Moderate Resolution Imaging Spectroradiometer) 센서를 이용한 산출물인 순광합성량과 총일차생산량 자료를 바탕으로 모형의 보정(2007)및 검증(2008)을 실시하였다. 모형의 최적의 수문, 생리생태학, 토양의 매개변수를 선정하여 검증한 결과, 유출량에 대한 Nash-Sutcliffe 모형효율은 0.84, 증발산, 토양수분, 총일차생산량, 순광합성량의 결정계수는 0.49, 0.18, 0.38, 0.93 이었다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.04a
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• pp.271-276
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• 2003

The Moderate Resolution Imaging Spectroradiometer (MODIS) on the Earth Observing System (EOS) of Terra and Aqua satellites, launched in December 1999 and May 2002, has been directly received by Korea Aerospace Research Institute (KARI) ground station facility from July 2002. MODIS scans a swath width of 2330 km that is sufficiently wide to cover Korean peninsular, Yellow and East Sea at once. The MODIS has 36 spectral bands between 0.415 $\mu\textrm{m}$ and 14.235 $\mu\textrm{m}$, i.e., through the visible into the thermal infrared. MODIS has been observed active fires, floods, smoke transport, dust storms, severe storms since February of 2000. The satellite imagery obtained through the MODIS will be utilized for many application such as national territorial management, agriculture, natural environment, atmosphere and ocean, etc. In this study is to introduce various application field of MODIS imagery and data processing system.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.269-273
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• 2003

In the rice planted acreage estimation, high precise measurement and laborsaving are required by using satellite data. A method referring accurate agricultural plot vector data was used in this paper which improves the estimation accuracy of rice planted acreage compared with conventional methods. In this method, satellite data are not used for totalization, although they are used to discriminate whether the fields are rice planted or not. This paper described the result of the above method using to ASTER-VNIR data.

• Proceedings of the KIEE Conference
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• 1998.11a
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• pp.37-39
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• 1998

The hybrid step motor has found applications in a wide range of mechanical systems as a low cost, open-loop positioning device. The step motor provides good stiffness at rest against disturbing load influences, a combination of moderate speed fine resolution, high reliability and simplicity. In recent years, considerable competition has arisen over the technological issue of wheather the device should be applied as a 2-Phase or 5-Phase machine. In this paper, to compare two systems, we have atempted to derive the mathematical. model, and analysed operating detent torque with this model. The analysis shows that a fundamental component of the permeance distribution produces the average torque and that harmonic components produce the ripple torque.

• Korean Journal of Remote Sensing
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• v.23 no.1
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• pp.1-5
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• 2007

Relatively simplified method for determination of surface reflectance has been used by using the ratio between SWIR and VIS band reflectance over land surface. The surface reflectance ratios (SWIR/VIS) were estimated over land in Korea from Terra Moderate Resolution Imaging Spectre-radiometer (MODIS) L1 data. The ratios by using the minimum reflectance technique were lower than those by MODIS operational aerosol retrieval algorithm. Although the comparison between MODIS and sunphotometer Aerosol Optical Thickness (AOT) has a good correlation coefficient (R=0.84), slightly overestimated MODIS AOTs were shown with a slope of linear regression line of 0.89. The comparison between the ratio and AOT dearly exhibit that the error of MODIS AOT could be originated from the underestimated surface reflectances by MODIS operational algorithm.

• Korean Journal of Remote Sensing
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• v.26 no.6
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• pp.665-673
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• 2010

The role of remote sensing in phenological studies is increasingly regarded as a key in understanding large area seasonal phenomena. This paper describes the application of Moderate Resolution Imaging Spectroradiometer (MODIS) time series data for vegetation classification using seasonal variation patterns. The vegetation seasonal variation phase of Seoul and provinces in Korea was inferred using 8 day composite MODIS NDVI (Normalized Difference Vegetation Index) dataset of 2006. The seasonal vegetation classification approach is performed with reclassification of 4 categories as urban, crop land, broad-leaf and needle-leaf forest area. The BISE (Best Index Slope Extraction) filtering algorithm was applied for a smoothing processing of MODIS NDVI time series data and fuzzy classification method was used for vegetation classification. The overall accuracy of classification was 77.5% and the kappa coefficient was 0.61%, thus suggesting overall high classification accuracy.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.230-230
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• 2016

Hydrological modeling is a very complex task dealing with multi-source of data, but it can be potentially benefited from recent improvements and developments in remote sensing. The estimation of actual land surface evapotranspiration (ET), an important variable in water management, has become possible based entirely on satellite data. This study adopted a Surface Energy Balance Algorithm for Land (SEBAL) with the use of MODerate Resolution Imaging Spectrometer (MODIS) satellite products. The SEBAL model is one of the commonly used approach for the ET estimation. A primary advantage of the SEBAL model is rather its minimum requirement for ground-based weather data. The MODIS provides ET (MOD16) product that is based on the Penman-Monteith equation. This study aims to further develop the SEBAL model by employing a more rigorous parameterization scheme including the estimation of uncertainty associated with parameter and model selection in regression model. Finally, the proposed model is compared with the existing approaches and comprehensive discussion is then provided.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.140-140
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• 2016

수분 이용효율(Water Use Efficiency, WUE)은 식생이 흡수한 수분 중 증발산에 이용한 비율로, 육상생태계의 수문학적 순환 및 탄소 순환의 기능을 측정할 수 있는 중요한 지표이다. 또한 이는 특정 지역의 기후 조건이나 토지 피복과 같은 다양한 요인에 따라 변할 수 있다. 본 연구에서는 한반도에서 2010년부터 2014년까지의 기후 요인(강수, 기온)과 토지 피복에 따른 WUE의 변화를 살펴본다. MODerate resolution Imaging Spectroradiometer (MODIS) 기반 총일차생산성(Gross Primary Productivity, GPP), 증발산량(Evapotranspiration, ET), 잎면적지수(Leaf Area Index, LAI)와 Willmot의 기상자료 등 대상지역에 대한 격자 자료를 사용한다. 구체적으로 숲, 초원, 농지와 같이 다양한 토지 피복 조건에 대한 월간 및 연간 WUE(=GPP/ET)를 산정하고, 이의 LAI나 기후 조건(강수, 기온)과의 관계를 분석하고자 상관성 및 요인 분석을 진행한다. 기후 조건 및 토지 피복 조건을 고려한 15년간 한반도에서의 WUE의 변화에 대한 분석은 앞으로의 수자원 관리 및 산림 정책에 활용할 수 있을 것으로 판단된다.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.22-22
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• 2018

본 연구에서는 수문학적 가뭄을 분석하기 위해 두가지 지수를 개발하여 소개하고자 한다. 첫번째는, 물수지식을 기반으로 산정된 Water Budget-based Drought Index(WBDI)로 강우와 증발산의 차이를 이용하여 산정한다. 두 번째는 에너지 수지식을 기반으로 산정된 Energy-based Water Deficit Index(EWDI)로 에너지 수지 기반의 증발산, 태양복사에너지와 토양수분 등을 이용하여 산정한다. 두가지 지수 모두 인공위성 영상 자료를 활용하였다. WBDI 산정을 위한 강수량 자료는 Tropical Rainfall Measuring Mission(TRMM)과 Global Precipitation Mission(GPM)를 활용하였으며, 증발산 자료는 Moderate Resolution Imaging Spectroradiometer (MODIS) 자료를 활용하였다. EWDI 산정에 필요한 입력자료는 모두 MODIS 자료를 활용하였다. 산정된 두 가뭄지수의 수문학적 가뭄 분석을 위해 자연유출지점인 6개 지점을 선정하여 유출량 자료와 비교하였다. 유출량 자료를 활용하여 Error matrix 기법을 적용하여 두 수문학적 가뭄지수의 우리나라에서의 적용성을 파악하였다.

• Journal of Environmental Science International
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• v.27 no.11
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• pp.983-989
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• 2018

The real-time monitoring of surface vegetation is essential for the management of droughts, vegetation growth, and water resources. The availability of land cover maps based on remotely collected data makes the monitoring of surface vegetation easier. The vegetation index in an area is likely to be proportional to meteorological elements there such as air temperature and precipitation. This study investigated relationship between vegetation index based on Moderate Resolution Image Spectroradiometer (MODIS) and ground-measured meteorological elements at the Yongdam catchment station. To do this, 16-day averaged data were used. It was found that the vegetation index is well correlated to air temperature but poorly correlated to precipitation. The study provides some intuition and guidelines for the study of the droughts and ecologies in the future.