• ICROS
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• v.15 no.1
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• pp.22-28
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• 2009

병렬기구는 조립, 포장, 기계가공, 크레인, 수중공학, 항공 및 해양구조, 비행 및 3D 시뮬레이션, 위성 접시안테나 위치제어, 망원경 자세제어, 그리고 정형외과 수술 등 여러 분야에 사용되고 있다.

• Magazine of the Korean Society of Hazard Mitigation
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• v.6 no.4 s.23
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• pp.49-56
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• 2006

• Journal of the Korean Society of Marine Environment & Safety
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• v.2 no.S1
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• pp.39-50
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• 1996

국제간 정보통신전달 수단으로 인공위성과 해저케이블이 상호보안적으로 사용되어 왔다. 특히 최근에 와서는 해저 광케이블의 등장으로 국가간 정보통신전달 수단으로 케이블의 역할이 급격히 증대되고 있다. 해저케이블은 열악한 해양환경에 노출되어 있으므로 건설시나 운용중에 손상 받을 가능성이 아주 크며 그로 인한 파급효과가 엄청나다. 또한 해저케이블 사고시 복구에 많은 시간과 어려움이 뒤따르며 비용도 막대하다. 따라서 해저케이블의 안전성을 확보하는 것은 매우 중요하며 이에 대한 보호대책이 절실하다. 본 논문에서는 해저케이블의 건설 및 운용상에 발생할 수 있는 여러 불안전 요인들을 찾아 그에 대한 대책방안을 고찰해 보고자 한다.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.6
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• pp.536-542
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• 2023

Satellites represent cutting-edge technology, of ering significant advantages in spatial and temporal observations. National agencies worldwide harness satellite data to respond to marine accidents and analyze ocean fluctuations effectively. However, challenges arise with high-resolution satellite-based sea surface temperature data (Operational Sea Surface Temperature and Sea Ice Analysis, OSTIA), where gaps or empty areas may occur due to satellite instrumentation, geographical errors, and cloud cover. These issues can take several hours to rectify. This study addressed the issue of missing OSTIA data by employing LaMa, the latest deep learning-based algorithm. We evaluated its performance by comparing it to three existing image processing techniques. The results of this evaluation, using the coefficient of determination (R²) and mean absolute error (MAE) values, demonstrated the superior performance of the LaMa algorithm. It consistently achieved R² values of 0.9 or higher and kept MAE values under 0.5 ℃ or less. This outperformed the traditional methods, including bilinear interpolation, bicubic interpolation, and DeepFill v1 techniques. We plan to evaluate the feasibility of integrating the LaMa technique into an operational satellite data provision system.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.297-309
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• 2007

The first Korean geostationary weather satellite, Communications, Oceanography and Meteorology Satellite (COMS) will be launched in 2008. The ground station for COMS needs to perform geometric correction to improve accuracy of satellite image data and to broadcast geometrically corrected images to users within 30 minutes after image acquisition. For such a requirement, we developed automated and fast geometric correction techniques. For this, we generated control points automatically by matching images against coastline data and by applying a robust estimation called RANSAC. We used GSHHS (Global Self-consistent Hierarchical High-resolution Shoreline) shoreline database to construct 211 landmark chips. We detected clouds within the images and applied matching to cloud-free sub images. When matching visible channels, we selected sub images located in day-time. We tested the algorithm with GOES-9 images. Control points were generated by matching channel 1 and channel 2 images of GOES against the 211 landmark chips. The RANSAC correctly removed outliers from being selected as control points. The accuracy of sensor models established using the automated control points were in the range of $1{\sim}2$ pixels. Geometric correction was performed and the performance was visually inspected by projecting coastline onto the geometrically corrected images. The total processing time for matching, RANSAC and geometric correction was around 4 minutes.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.24 no.3
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• pp.429-435
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• 2019

The drifters of the Global Drifter Program were deployed in the northern East Sea for two years from March 2015 to compare and validate currents estimated from sea-level measurements with the SARAL/AltiKa altimetry satellite mission, specially designed to accurately measure sea level in the near-coastal area. The collocated (less than 20 km apart) directly measured current from GPS locations every 30 minutes and the currents normal to the satellite tracks show a similar correlation in the area shallower than 200 m depth as the open ocean and it makes it possible to investigate the time variations of the current along the coast in the northern East sea, where direct observations of current are scarce. The Liman Current along the Siberian coast is found to be southward all year round, but the North Korean Cold Current flows southward only in the summer. The North Korean Cold Current south of the Musudan cape mostly flows to the south, but the current direction depends on the presence of an eddy around the coast of Musudan cape.

• Korean Journal of Remote Sensing
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• v.37 no.3
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• pp.615-625
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• 2021

The coastal areas around Palau Island and Tonga Island, near the Pacific equator, consist of coral reefs, mangrove and seaweed. In particular, understanding the optical properties of sea surface water in coral reef habitats helps improve the accuracy of remote sensing based habitat mapping and identify tropical ecosystem characteristics. Here, we collected spectral characteristics of sea surface water of Palau Island and Tonga Island and analyzed the concentration of suspended matters, absorption coefficient, and remote sensing reflectance to understand the seawater characteristics of the coral reef habitats. Based on the results of the suspended matter concentration analysis, we developed and verified an empirical algorithm to derive the concentration from satellite data using remote sensing reflectance of three bands, 555, 625, 660 nm, showed a high determinant coefficient, 0.98. In conclusion, coral reef habitats in tropical regions are characterized by CASE-I water in terms of the marine optics with oligotrophic properties, and require monitoring using continuous collection and analysis of field data.

• Korean Journal of Remote Sensing
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• v.22 no.2
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• pp.87-99
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• 2006

The Median Resolution Sensors (MRSs) for land observation such as Landsat-ETM+ and SPOT-HRV are more effective than Ocean Color Sensors (OCSs) for studying of detailed ecological and biogeochemical components of the coastal waters. In this study, we developed suspended sediment algorithm for Landsat TM/ETM+ by considering the spectral response curve of each band. To estimate suspended sediment concentration (SS) from satellite image data, there are two difference types of algorithms, that are derived for enhancing the accuracy of SS from Landsat imagery. Both empirical and remote sensing reflectance model (hereafter referred to as $R_{rs}$ model) are used here. This study tried to compare two algorithm, and verified using in situ SS data. It was found that the empirical SS algorithm using band 2 produced the best result. $R_{rs}$ model-based SS algorithm estimated higher values than empirical SS algorithm. In this study we used $R_{rs}$ model developed by Ahn (2000) focused on the Mediterranean coastal area. That's owing to the difference of oceanic characteristics between Mediterranean and Korean coastal area. In the future we will improve that $R_{rs}$ model for the Korean coastal area, then the result will be advanced.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.8
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• pp.702-709
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• 2016

By means of the our satellite development for the past 20 years, it ensure us to obtain domestic independent development capabilities. In the case of practical-class Low-Earth Orbit(LEO) remote sensing satellites, we become a world-class developer. Furthermore, we acquire the technology to develop domestic-leading geostationary satellites, depending on the mission. Currently, we proceed with the next-generation mid-size satellite development program featuring standard bus for the expansion of the world market and has embarked on the development of lunar orbiter from this year.

• Korean Journal of Remote Sensing
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• v.23 no.4
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• pp.311-321
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• 2007

The diffuse attenuation coefficient for down-welling irradiance $K_d({\lambda})$, which is the propagation of down-welling irradiance at wavelength ${\lambda}$ from surface to a depth (z) in the ocean, and underwater visibility are important optical parameters for ocean studies. There have been several studies on $K_d({\lambda})$ and underwater visibility around the world, but only a few studies have focused on these properties in the Korean sea. Therefore, in the present study, we studied $K_d({\lambda})$ and underwater visibility around the coastal area of the Yellow Sea, and developed $K_d({\lambda})$ and underwater visibility algorithms for ocean color satellite sensor. For this research we conducted a field campaign around the Yellow Sea from $19{\sim}22$ September, 2006 and there we obtained a set of ocean optical and environmental data. From these datasets the $K_d({\lambda})$ and underwater visibility algorithms were empirically derived and compared with the existing NASA SeaWiFS $K_d({\lambda})$ algorithm and NRL (Naval Research Laboratory) underwater visibility algorithm. Such comparisons over a turbid area showed small difference in the $K_d({\lambda})$ algorithm and constants of our result for underwater visibility algorithm showed slightly higher values.