• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.251-254
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• 2008

The German radar satellite TerraSAR was launched in 2007. In this study, interferogram is generated using TerraSAR-X data and DEM (Digital Elevation Model). Coregistration procedures used with SAR images (i.e. master and slave) in traditional method results in serious errors for high resolution TerraSARX data because of the mutual shift of the master and slave images due to topography. This error becomes more serious in mountainous areas in which the coherence between interferometric pairs is relatively low. Here we processed a geometric coregistration with DEM exploiting height information. Through the method, interferometry processing is fulfilled to generate a qualified interferogram and coherence is improved. This approach will help high resolution X-band SAR interferometry in mountainous area.

• Journal of Information Technology Services
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• v.21 no.6
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• pp.127-145
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• 2022

Luna Coin, which ranked eighth in the global market capitalization and established itself as a super-large stablecoin, plunged overnight, shocking the market. Therefore, this study proposed the direction of Korea's stablecoin regulation, focusing on the Terra-Luna situation, starting with the question of whether the stable coin's value, 'stability', can be trusted. The whole story of the Terra-Luna incident was examined in depth and the problems were pointed out, and the direction of domestic stable coin regulation was described based on overseas cases. In the absence of any legal guidelines for stablecoin at the moment, we hope that this study will provide a minimum stabilizer in the virtual asset market and help protect investors.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.2
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• pp.457-467
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• 2014

This study is to evaluate the snowmelt impact on dam inflow for the Chungju Dam watershed $6,642.0km^2$ using Terra MODIS (Moderate-Resolution Imaging Spectroradiometer) and Soil and Water Assessment Tool (SWAT). To determine the SWAT snowmelt parameter; snow cover depletion curve (SCDC) the snow depth distribution (SDD) using Terra MODIS was used, the snow depth was spatially interpolated using snowfall data of ground meteorological stations. For 10 sets (2000-2010) data during snowmelt period (November-April), the sno50cov parameter, that is, the 50% coverage at a fraction of SCDC which determines the shape of snow depletion process, showed the values of 0.4 to 0.7. The SWAT model was calibrated with average $R^2$ of 0.54 using the sno50cov of each year. The 10 years average streamflow during snowmelt period was 104.3 mm which covers 12.0% of the annual streamflow.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.667-675
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• 2011

In this paper, we propose an automatic image-to-image registration between high resolution multi-sensor images. To do this, TerraSAR-X image was shifted according to the initial translation differences of the x and y directions between images estimated using Mutual Information method. After that, the Canny edge operator was applied to both images to extract linear features. These features were used to design a cost function that finds matching points based on the similarities of their locations and gradient orientations. For extracting large number of evenly distributed matching points, only one point within each regular grid constructed throughout the image was extracted to the final matching point pair. The model, which combined the piecewise linear function with the global affine transformation, was applied to increase the accuracy of the geometric correction, and the proposed method showed RMSE lower than 5m in all study sites.

• Proceedings of the Korea Water Resources Association Conference
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• 2016.05a
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• pp.318-318
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• 2016

위성은 준 실시간으로 국토 전체의 관측과 미계측/비접근 지역의 관측도 가능하여 가뭄, 홍수 등 수재해와 관련된 분석 자료로 활용되고 있으며, 위성 기반의 수재해 모니터링 적용성에 대한 연구 또한 수행되고 있다. 위성에서 관측된 자료는 NASA, JAXA 등의 위성 관리 센터에서 알고리즘을 적용하여 인터넷으로 제공하고, 최근 K-water에서는 수자원분야의 위성활용을 위해 위성 자료 수집 시스템을 갖추어 Aqua/Terra MODIS, GPM, GCOM-W1 등의 위성 자료를 수집하고 있다. 위성 자료는 5분~16일 등의 다양한 주기로 제공되고 있으며, 자료 타입, 측정 시간 등의 간단한 정보만 파일명으로 표시되어 위성의 위치(경위도) 및 해당 지점의 위성 자료를 얻기 위해서는 위성 자료를 확인해야만 하는 번거로움이 따른다. 본 연구에서는 순차적으로 관측된 위성 자료의 시 공간적 속성정보를 추출하고 해당 정보를 영상과 함께 맵핑하여, 시간의 흐름에 따른 위성 궤도의 시각화 방안을 제시하였다. 위성 궤도의 시각화 방안으로 사용된 위성 자료는 Terra MODIS의 'MOD02SSH', GPM GMI 센서의 'GPROF' 자료 타입을 사용하였다. 'MOD02SSH'는 5분 동안 5km의 공간해상도로 측정한 자료가 1개의 파일이며, 'GPROF'는 5분 동안 4km의 공간해상도로 측정한다. 공전 주기의 검증을 위해 케플러의 제3법칙을 적용한 Terra 위성의 공전주기는 98.75분으로 계산되며, 위성 자료의 공전주기는 98.87분으로 나타난다. 검증 결과 약 0.12초의 오차가 발생하며, 정확한 위성 고도와 높은 해상도의 위성 자료를 통해 오차의 감소가 가능하다. 이를 통해 시각화 된 동적 시계열 이미지는 시간에 따른 위성 궤도의 정보를 추출 할 수 있다. 이는 수재해 정보시스템의 모니터링을 위해 사용 가능하고, 시간에 따른 위성 궤도 정보를 통하여 필요한 시간대의 위성 위치 정보, 해당 지점의 관측 자료를 효율적으로 수집하여 자료 수집을 위한 시간 단축이 가능하며, 사용자 또는 관리자를 위한 모니터링 수행 또한 효율적인 운영이 가능할 것으로 사료된다.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.569-572
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• 2002

Terra MODIS is one of the few space-borne sensors currently capable of acquiring radiometric data over the range of view angles. Institute of Industrial Science, University of Tokyo, has been receiving Terra MODIS data at Tokyo since May 2001 and Asian Institute of Technology at Bangkok since May 2001. They can cover whole East Asia and is expected to monitor environmental changes regularly such as deforestation, forest fires, floods and typhoon. Over eight hundred scenes have been archived in the storage system and they occupy 2 TB of disk space so far. In this study, MODIS data processing system on WWW is developed including following functions: spectral subset (250m, 500m, 1000m channels), radiometric correction to radiance, spatial subset of geocoded data as a rectangular area with latitude-longitude grid system in HDF format, generation of a quick look file in JPEG format. Users will be notified just after all the process have finished via e-mail. Using this system enables us to process MODIS data on WWW with a few input parameters and download the processed data by FTP access. An easy to use interface is expected to promote the use of MODIS data. This system is available via the Internet on the following URL from September 1 2002, "http : //webmodis.iis.u-tokyo.ac.jp/".

• Atmosphere
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• v.12 no.4
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• pp.56-68
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• 2002

In this study, an overview of the Earth Observing System (EOS) program is provided with discussions on its spacecrafts and instruments, and on the scientific issues. The EOS satellites aim at monitoring the Earth environmental system by observing parameters of subsystems such as atmosphere, ocean, land, and biosphere. The first EOS flagship, Terra, was launched on December 1999. Five instruments onboard Terra can measure cloud and aerosol properties, radiation, terrestrial surface, and ocean color. The second EOS flagship, Aqua, which was launched on May 2002, loads six instruments that measure clouds, radiation, precipitation, terrestrial surface, ocean color and sea surface temperature. The observational data available from the EOS satellites may complement data from the Communication-Oceanography-Meteorology satellite, which will be launched in 2008, for meteorological and environmental forecasts.

• Proceedings of the Korea Water Resources Association Conference
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• 2008.05a
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• pp.1092-1096
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• 2008

최근 국내에서 저해상도 위성영상을 이용한 적설 분포의 추출연구가 융설과 관련된 수문학적 연구에 이용되기 시작하였다. 한반도와 같이 넓은 지역을 대상으로 추출하는 과정에서 대기에 의한 방해가 너무 큰 영상은 구름 아래 지표면의 정보를 얻을 방법이 없어 해당 날짜의 영상을 제외 할 수밖에 없는 문제가 생긴다. 본 연구에서는 센서의 특성과 영상의 촬영 시간, 그리고 촬영 각도가 달라 서로 다른 대기의 영향을 받는 Terra MODIS 위성영상과 NOAA AVHRR 위성영상을 이용하여 각각의 적설 분포를 추출하는 방법을 비교 연구함으로써 영상을 분석하는데 있어 구름의 영향을 최소화 하고자 하였다. 2004년부터 2006년까지 겨울철의 적설이 발생한 기간을 대상으로 총 3개년의 영상을 분석한 결과를 바탕으로 두 영상으로부터 추출된 적설분포의 차이를 우리나라의 충주댐 유역을 중심으로 비교하였다. 밴드별 파장대의 반사 특성을 이용한 MODIS snow cover와 임계값을 선정하여 구하는 NOAA AVHRR는 서로 다른 적설분포를 보였다고 판단되며, 이는 해상도와 영상 합성, snow cover 추출 알고리즘의 차이 및 대기 현상의 영향 등으로 인하여 추출면적 값이 차이를 보이는 것이라 생각된다. 두 영상에 의한 추출면적의 비교분석 결과, 적설분포의 추출에 있어서 두 영상을 서로 절충하여 사용할 수 있다고 판단된다.

• Proceedings of the KSRS Conference
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• 2008.10a
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• pp.422-425
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• 2008

TerraSAR-X is new radar satellite operated at X-band, multi polarization, and multi beam mode. Compared with C-band or L-band SAR, the X-band system inherently suffers from more temporal decorrelation, but is more sensitive to surface deformation monitoring due to short wavelength (3.1 cm) and high spatial resolution (1m-3m). It is generally expected that sensitivity to estimate surface movement using TerraSAR-X will be increased by the factor of 10, compared to current C-band system with low spatial resolution such as ERS-2, Envisat. Many urban areas are experiencing land subsidence due to water, oil and natural gas withdrawal, underground excavation, sediment compaction, and so on. Monitoring of surface deformation is valuable for effectively limiting damage areas. In addition high accuracy and spatially dense subsidence map can be achieved by X-band InSAR observation, promoting identification and separation of various subsidence processes and leading to enhanced understanding via mechanical modeling. In this study we will introduce some initial InSAR results using new TerraSAR-X SAR data for surface deformation monitoring.

• Journal of The Korean Society of Agricultural Engineers
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• v.55 no.6
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• pp.47-55
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• 2013

The objective of this study is to evaluate the applicability of Communication, Ocean, and Meteorological Satellite (COMS) Geostationary Ocean Color Imager (GOCI) vegetation indices on a quantitative analysis. For evaluation, the vegetation indices such as RVI, NDVI and SAVI were extracted by using COMS GOCI and Terra Moderate Resolution Imaging Spectroradiometer (MODIS) imageries. The 4,000 points using simple random sampling (SRS) method were randomly extracted from land areas except ocean to compare the vegetation indices from two images. The results of linear regression showed that the regression coefficients of RVI, NDVI, and SAVI between COMS GOCI and Terra MODIS were 0.66~0.82, 0.71~0.83, and 0.71~0.83, respectively. Especially, the regression coefficients of RVI (r=0.85), NDVI (r=0.91) and SAVI (r=0.91) were strongly related from September 2011 to January 2012. Thus, COMS GOCI can be substituted for particular periods and it needs to verify additionally.