• 한국농림기상학회지
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• 제14권2호
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• pp.53-62
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• 2012

고해상도 기상자료 제공과 농림 분야에서의 요구를 충족시키기 위하여 LAPS를 이용하여 경기도 지역을 100m 해상도로 분석하였다. 구축된 시스템은 수치예보과에서 생산되는 6시간 간격 예측자료를 초기추정치로 사용하고, 각 관측자료를 동화하여 지표 온도와 습도 바람을 분석한다. 기존 분석시스템의 기상관측자료의 수집 방식을 개선하여 자료 수집에 소요되는 시간을 성공적으로 단축시킴으로써 약 20분 내에 기온, 상대습도, 풍향, 풍속에 대한 고해상도 분석결과 제공이 가능하게 되었다. 그러나 앞으로 LAPS 분석결과를 이용하여 관측이 가능한 지역 이외에 어느 지역에서든 정확한 농업기상정보를 산출할 수 있게 하려면 다양한 기상자료의 활용과 지표이용도의 개선, 관측지점의 영향반경을 최적화 시키는 과정들이 추가로 연구되어야 할 것이다. 현재 구축된 시스템의 분석결과 정확도는 떨어지지만 LAPS의 내부 알고리즘에 대한 미세한 조정으로 향상이 가능하므로 농업기상요소 생성을 위한 최적화 작업들을 수행한다면 정확도 향상을 꾀할 수 있을 것이다. 또한 다양한 기상요소에 대한 분석이 가능하기 때문에 특별한 기상요소들을 필요로 하는 농림 분야의 요구를 충족 시킬 수 있도록 분석요소의 확장이 가능 할 것이다.

• 대한원격탐사학회지
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• 제40권2호
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• pp.141-150
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• 2024

Ground subsidence in urban areas is mainly caused by anthropogenic factors such as excessive groundwater extraction and underground infrastructure development in the subsurface composed of soft materials. Global Navigation Satellite System data with high temporal resolution have been widely used to measure surface displacements accurately. However, these point-based terrestrial measurements with the low spatial resolution are somewhat limited in observing two-dimensional continuous surface displacements over large areas. The synthetic aperture radar interferometry (InSAR) technique can construct relatively high spatial resolution surface displacement information with accuracy ranging from millimeters to centimeters. Although constellation operations of SAR satellites have improved the revisit cycle, the temporal resolution of space-based observations is still low compared to in-situ observations. In this study, we evaluate the extraction of a time-series of surface displacement in Incheon Metropolitan City, South Korea, using the small baseline subset technique implemented using the commercial software, Gamma. For this purpose, 24 COSMO-SkyMed X-band SAR observations were collected from July 12, 2011, to August 27, 2012. The time-series surface displacement results were improved by reducing random phase noise, correcting residual phase due to satellite orbit errors, and mitigating nonlinear atmospheric phase artifacts. The perpendicular baseline of the collected COSMO-SkyMed SAR images was set to approximately 2-300 m. The surface displacement related to the ground subsidence was detected approximately 1 cm annually around a few Incheon Subway Line 2 route stations. The sufficient coherence indicates that the satellite orbit has been precisely managed for the interferometric processing.

• 디지털융복합연구
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• 제11권8호
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• pp.273-279
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• 2013

본 연구에서는 변조전달함수(Modulation transfer function, MTF)를 이용한 컴퓨터 방사선영상의 감도 노출 분류에 따른 공간분해능을 평가하여 컴퓨터 방사선영상 획득의 기초자료로 제시하고자 하였다. 본 실험에서는 $100{\mu}mm$ 픽셀의 영상판을 이용하여 엣지법의 MTF를 측정하였다. 방사선 선질은 IEC 61267에서 권고하고 있는 RQA5를 이용하였다. X-선이 조사된 영상판은 감도 노출 분류를 50, 100, 200, 300, 400, 600, 800, 1200으로 각각 설정한 후 디지털 영상화하였다. 최종 획득된 영상들은 공인된 영상분석 프로그램인 image J와 Origin 8.0을 이용하여 MTF 50%와 10%를 구하여 평가하였다. 그 결과 감도 노출 분류 200에서 가장 우수한 MTF 50%($1.979{\pm}0.114lp/mm$)와 MTF 10%($3.932{\pm}0.041$)의 공간주파수를 구하였다. 따라서 골절 등과 같이 높은 공간분해능을 요구하는 질병진단에 유용할 것으로 사료된다.

• 한국수자원학회논문집
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• 제56권10호
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• pp.641-653
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• 2023

기후변화와 도시화의 영향으로 인해 자연재해의 발생빈도와 규모가 증가하고 있다. 특히 도시 침수는 발생 시간이 짧고 막대한 인명 및 경제적 손실을 초래할 수 있기 때문에 신속하고 정확도 높은 예측 정보 생산이 중요하다. 하지만, 기존 물리과정 및 인공지능 기반 기법은 고해상도 침수 해석을 위해 많은 전산 자원이나 데이터가 요구되는 한계가 있다. 본 연구에서는 딥러닝 기반 초해상화(Super-Resolution) 기법을 통한 고해상도 도시 침수 해석 방법을 제안하고 적용성을 평가한다. 제안된 방법은 고해상도 물리 모형의 결과로 훈련된 초해상화 딥러닝 모형을 이용하여 저해상도 침수 해석 이미지를 고해상도로 변환한다. 미국 포틀랜드 도심지의 두 가지 침수 사례에 대해 적용, 4 m 공간해상도 물리 모의 결과를 1 m 급 고해상도 침수 해석 정보로 초해상화 하였으며, 초해상화 이미지와 고해상도 원본 간 높은 구조적 유사성이 확인되었다. 성능 지표로 평가한 결과, 전체 검증 대상 이미지에 대한 평균 PSNR 22.77 dB, SSIM 0.77로 우수하여, 초해상화 기법의 도시 침수 해석 적용성이 검증되었다. 제안된 방법은 적은 양의 침수 시나리오만으로도 효율적인 딥러닝 모형 훈련이 가능하고, 물리 모형의 정보를 최대한 활용할 수 있기 때문에, 고해상도 도시 침수 정보 생산에 효과적으로 사용될 수 있을 것으로 기대된다.

• 한국지진공학회논문집
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• 제27권5호
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• pp.221-230
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• 2023

This study proposes a methodology for assessing seismic liquefaction hazard by implementing high-resolution three-dimensional (3D) ground models with high-density/high-precision site investigation data acquired in an area of interest, which would be linked to geotechnical numerical analysis tools. It is possible to estimate the vulnerability of earthquake-induced geotechnical phenomena (ground motion amplification, liquefaction, landslide, etc.) and their triggering complex disasters across an area for urban development with several stages of high-density datasets. In this study, the spatial-ground models for city development were built with a 3D high-precision grid of 5 m × 5 m × 1 m by applying geostatistic methods. Finally, after comparing each prediction error, the geotechnical model from the Gaussian sequential simulation is selected to assess earthquake-induced geotechnical hazards. In particular, with seven independent input earthquake motions, liquefaction analysis with finite element analyses and hazard mappings with LPI and LSN are performed reliably based on the spatial geotechnical models in the study area. Furthermore, various phenomena and parameters, including settlement in the city planning area, are assessed in terms of geotechnical vulnerability also based on the high-resolution spatial-ground modeling. This case study on the high-precision 3D ground model-based zonations in the area of interest verifies the usefulness in assessing spatially earthquake-induced hazards and geotechnical vulnerability and their decision-making support.

• 전기전자학회논문지
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• 제18권1호
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• pp.8-18
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• 2014

Electrical resistance tomography (ERT) has high temporal resolution characteristics therefore it is used as an alternative technique to visualize two-phase flows. The image reconstruction in ERT is highly non-linear and ill-posed hence it suffers from poor spatial resolution. In this paper, the inverse problem is solved with homogeneous data used as a prior information to reduce the condition number of the inverse algorithm and improve the spatial resolution. Numerical experiments have been carried out to illustrate the performance of the proposed method.

• Journal of Advanced Marine Engineering and Technology
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• 제34권3호
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• pp.407-412
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• 2010

According to the remarkable advances in sonar technology, positioning capabilities and computer processing power we can accurately image and explore the seafloor in hydrography. Especially, Multibeam Echo Sounder can provide nearly perfect coverage of the seafloor with high resolution. Since the mid-1990's, Multibeam Echo Sounders have been used for hydrographic surveying in Korea. In this study, new marine data set as an effective decision-making tool in various fields was proposed by visualizing and combining with Multibeam sonar data and marine spatial data sets such as satellite image and digital nautical chart. The proposed method was tested around the port of PyeongTaek-DangJin in the west coast of Korea. The Visualization and fusion methods are described with various marine data sets with processing. We demonstrated that new data set in marine GIS is useful in safe navigation and port management as an efficient decision-making tool.

• 대기
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• 제17권3호
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• pp.255-268
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• 2007

This study generated and evaluated the high resolution (5 km) gridded data of monthly mean, maximum and minimum temperature from 2002 to 2005 over South Korea using a modified PRISM(Parameter-elevation Regressions on Independent Slopes Model: K-PRISM) developed by Daly et al. (2003). The performance of K-PRISM was evaluated by qualitative and quantitative ways using the observations and gridded data derived by inverse distance weighting (IDW) and hypsometric methods (HYPS). For the generation of high resolution gridded data, geographic informations over South Korea, such as the digital elevation, topographic facet and coastal proximity, are derived from the 1 km digital elevation data. The spatial patterns of temperature derived by K-PRISM were more closely linked to topography and coastal proximity than those by IDW. The K-PRISM performed much better than IDW for all months and temperatures, but it was equal to or slightly better than the HYPS. And the performances of K-PRISM were better in the minimum and mean temperature (winter) than the in maximum temperature (summer).

• 대한원격탐사학회:학술대회논문집
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• 대한원격탐사학회 2005년도 Proceedings of ISRS 2005
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• pp.466-469
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• 2005

In this study e-map component was designed and developed to possibly overlay with all kinds of thematic maps in various scales and provide the all detailed information by using high-resolution satellite image and GIS. Also, this system has powerful map composition tool to display map such as legend, scale bar, index map and so on. For this, this e-map component was designed by using UML and developed based on Windows 2000 and implemented by using Visual Basic 6.0 as development programming language, Map Objects 2.1 of ESRI as GIS component. Through this system, the forest officials could generate more detailed topography and desired thematic map. In addition, the data consistency in DBMS could be maintained by using SDE (Spatial Database Engine) for their job and share the standard forest database with others in real time.

• Ocean and Polar Research
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• 제42권1호
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• pp.49-61
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• 2020

We analyzed the morphological characteristics of OCC (Ocean Core Complexes) in the middle part of the Central Indian Ridge (MCIR) using high-resolution geophysical data recorded on the Deep-Tow SideScan Sonar IMI-30 system. In terms of slope-gradient variations calculated from the high-resolution bathymetry data, the normal faults formed by seafloor spreading were associated generally with slopes > 30° and resulted in high backscatter intensities, which reflect more topographic effects than acoustic medium variation. However, the areas associated with gentle slopes < 10° tend to show the backscatter intensities reflecting the acoustic characteristic of the medium. We show that the detachment faults exposing the OCCs were initiated with high-angle normal faults (58°) exhibiting outward and inward dips of a breakaway zone. In order to examine the spatial distribution of OCC structures, we characterized the transition from magmatic-dominant seafloor with abyssal hills to tectonic-dominant seafloor with OCC using the down-slope direction variation. The slope direction of the seafloor generally tends to be perpendicular to the ridge azimuth in the magmatic-dominant zone, whereas it becomes parallel to the given ridge azimuth near the OCC structures. Therefore, this spatial change of seafloor slope directions indicates that the formation of OCC structures is causally associated with the tectonic-dominant spreading rather than magmatic extension. These results also suggest that the topographical characteristics of seafloor spreading and OCC structures can be distinguished using high-resolution geophysical data. Thus, we propose that the high-resolution bathymetry and backscatter intensity data can help select potential areas of exploitation of hydrothermal deposits in MCIR effectively.