• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.225-230
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• 2007

Currently, looking at the field of producing national coastlines, the lengths of coastlines are inaccurate due to the vague definition of dividing coastline boundaries and insufficient observation data. The level of accuracy and reliability of previous data are also in the very low. This paper used aerial photographs with certain intervals to monitor the change in coastal areas of Songjeong, Haeundae, Kwanganri, Songdo and Dadaepo. The local area subjected for this research was limited to areas near Busan. Launching quantitative/time series analyses on the change of coastal areas using aortal photographs, satellite image data and RTK-GPS surveys. And developing an automatic edge detection program to extract coastlines, suggesting the performance of the program and analyzing the efficiency of the program.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.2055-2058
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• 2004

This paper formulates a yaw angle determination algorithm for earth-point satellite. The algorithm based on vector observation, is implemented with the limited vector measurements. The proposed algorithm doesn't require gyro measurement data but magnetic sensor measurement data. In order to confirm the usefulness of the proposed method, we investigate the simulated telemetry data of the KOMPSAT-2, a satellite that is scheduled to be launched into a 685km altitude sun synchronous circular orbit in 2005.

• Atmosphere
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• v.17 no.3
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• pp.281-289
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• 2007

Micrometeorlogical and upper air observation have been conducted in order to determine the atmospheric boundary layer depth based on data from satellite and automatic weather systems. Terra/MODIS temperature profiles and sensible heat fluxes from the gradient method were used to estimate the mixed layer height over a coastal region. Results of the integral model were in good agreement with the mixed layer height observed using GPS radiosonde at Wolsung ($35.72^{\circ}N$, $129.48^{\circ}E$). Since the variation of the mixed layer height depends on the surface sensible heat flux, the integral model estimated properly the mixed layer height in the daytime. The buoyant heat flux, which is more important than the sensible heat flux in the coastal region, must be taken into consideration to improve the integral model. The vertical structure of atmospheric boundary layer can be analyzed only with the routine data and the satellite data.

• Proceedings of the KAIS Fall Conference
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• 2011.05a
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• pp.39-42
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• 2011

본 논문에서는 지하수 관정관리의 효율성을 위해 지리정보와 USN기술 기반의 통합된 모듈을 구축한다. 이 모듈에서는 GPS 위치 값, 환경 센서(수온, 수심, 전기전도도)의 값을 CDMA 통신 모듈을 통해 서버로 전달받아서 저장한다. 관정의 위치를 GIS맵상에서 표현을 하기 위해서 실측 지도와 위성사진 자료를 이용하여 GIS맵을 구축하여 시스템 화면상에 실측지도와 함께 지리정보를 맵핑한다. 통합된 클라이언트 형태로 시스템 서비스를 제공한다.

• Journal of Korea Multimedia Society
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• v.19 no.8
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• pp.1505-1515
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• 2016

The age of autonomous vehicles has come according to development of high performance sensing and artificial intelligence technologies. And importance of the vehicle's surrounding environment sensing and observation is increasing accordingly because of its stability and control efficiency. In this paper we propose an integrated platform for efficient networking, analysis and monitoring of multiple sensing data on the vehicle that are equiped with various automotive sensors such as GPS, weather radar, automotive radar, temperature and humidity sensors. From simulation results, we could see that the proposed platform could perform realtime analysis and monitoring of various sensing data that were observed from the vehicle sensors. And we expect that our system can support drivers or autonomous vehicles to recognize optimally various sudden or danger driving environments on the road.

• Journal of Positioning, Navigation, and Timing
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• v.11 no.3
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• pp.157-161
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• 2022

The Nuri rocket developed by South Korea was launched at approximately 07:00 UT on June 21, 2022. We use GPS observations obtained from the Korean GNSS network to analyze ionospheric total electron content (TEC) disturbances induced by the 2022 Nuri rocket launch. TEC disturbances are observed south over South Korea 4-5 min after the rocket launch. In addition, the maximum depletion in the vertical TEC shows approximately 8 TEC units (TECU). We also compute a horizontal velocity from initial ionospheric disturbances triggered by the 2022 Nuri rocket launch. Its velocity is about 1.4 km/s. It may be related to the rocket's flight trajectory at the observation time of the ionospheric TEC disturbance.

• Korean Journal of Remote Sensing
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• v.38 no.6_1
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• pp.1125-1139
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• 2022

In an unmanned aerial vehicles (UAVs) system, a physical offset can be existed between the global positioning system/inertial measurement unit (GPS/IMU) sensor and the observation sensor such as a hyperspectral sensor, and a lidar sensor. As a result of the physical offset, a misalignment between each image can be occurred along with a flight direction. In particular, in a case of multi-sensor system, an observation sensor has to be replaced regularly to equip another observation sensor, and then, a high cost should be paid to acquire a calibration parameter. In this study, we establish a precise sensor model equation to apply for a multiple sensor in common and propose an independent physical offset estimation method. The proposed method consists of 3 steps. Firstly, we define an appropriate rotation matrix for our system, and an initial sensor model equation for direct-georeferencing. Next, an observation equation for the physical offset estimation is established by extracting a corresponding point between a ground control point and the observed data from a sensor. Finally, the physical offset is estimated based on the observed data, and the precise sensor model equation is established by applying the estimated parameters to the initial sensor model equation. 4 region's datasets(Jeon-ju, Incheon, Alaska, Norway) with a different latitude, longitude were compared to analyze the effects of the calibration parameter. We confirmed that a misalignment between images were adjusted after applying for the physical offset in the sensor model equation. An absolute position accuracy was analyzed in the Incheon dataset, compared to a ground control point. For the hyperspectral image, root mean square error (RMSE) for X, Y direction was calculated for 0.12 m, and for the point cloud, RMSE was calculated for 0.03 m. Furthermore, a relative position accuracy for a specific point between the adjusted point cloud and the hyperspectral images were also analyzed for 0.07 m, so we confirmed that a precise data mapping is available for an observation without a ground control point through the proposed estimation method, and we also confirmed a possibility of multi-sensor fusion. From this study, we expect that a flexible multi-sensor platform system can be operated through the independent parameter estimation method with an economic cost saving.

• Korean Journal of Remote Sensing
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• v.33 no.6_1
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• pp.971-980
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• 2017

In this research, it was presented that the strategic approach for the long-term shoreline changes using historic digital aerial images can be effective for the analysis on the bangameori beach, west coast of South Korea. For this purpose, we collected several historic digital aerial images over 9 years in the research filed and conducted GPS-VRS surveying for GCP (Ground Control Point) acquisition. Also we collected existing two dimensional shoreline digital map which was published by KHOA (Korea Hydrographic and Oceanographic Agency) in the year 2013. With these multi data sets, we provided quantitative analysis on coastal erosion using the long-term shoreline changes in the beach. Also, As the results it was found that 2m sea level was retreated in the research period with maximum 0.31m length.

• Journal of Korean Society for Geospatial Information Science
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• v.24 no.1
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• pp.3-8
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• 2016

Due to the recent technical development and the enhancement of image resolution, Unmanned Airborne Vehicles(UAVs) have been used for various fields. A low altitude UAV system takes advantage of taking riverbed imagery at small rivers as well as land surface imagery on the ground. The bathymetric data are generated from the low altitude UAV system. The accuracy of the data is analyzed along water depths, comparing GPS observations and a DSM generated from UAV images. It is found that the depth accuracy of the geospatial data below 50 cm depth of water satisfies the regulation(${\pm}10cm$ spatial accuracy) of bathymetric surveying. Therefore this research shows that the geospatial data generated from UAV images at shallow regions of rivers can be used for bathymetric surveying.

• Journal of the Korea Society of Computer and Information
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• v.15 no.11
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• pp.47-56
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• 2010

In navigation, officers receive data about inside and outside of ship from several devices(ex, GPS / AIS / ECDIS / ARPA Radar / etc) in bridge, and use it to recognize and predict safety situations. However, observation work of a officer is still hard for a torrent of data from several devices, and the problem of inconsistent data among the devices. In previous research, we presented the conceptual model of Intelligent Navigation Safety Information System based on information fusion, and showed the example of the conceptual model using CF (Certainty Factor) expert system to solve this problem. The information fusion technology needs various reasoning skills, and CF expert system is not enough to express ambiguous or indefinite factors. In this paper, we propose the concept of an intelligent navigation information fusion using fuzzy expert system to describe the ambiguous factors, and show the validity of applying fuzzy expert system to the Navigation Safety Information System through the design and implementation of the proposed concept.