• Korean Journal of Remote Sensing
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• v.36 no.5_4
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• pp.1195-1207
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• 2020

With the development of GeoWeb technology, 2D/3D spatial information services through the web are also has been used increasingly in the application of disaster management. This paper is suggested to construct a web-based 3D geo-spatial information mapping platform to visualize various spatial information collected at the disaster site in a web environment. This paper is presented a web-based geo-spatial information mapping service plan for the various types of 2D/3D spatial data and large-volume LiDAR point cloud data collected at the disaster accident site using HTML5/WebGL, web development standard technology and open source. Firstly, the collected disaster site survey 2D data is constructed as a spatial DB using GeoServer's WMS service and PostGIS provided an open source and rendered in a web environment. Secondly, in order to efficiently render large-capacity 3D point cloud data in a web environment, a Potree algorithm is applied to simplifies point cloud data into 2D tiles using a multi-resolution octree structure. Lastly, OpenLayers3 based 3D web mapping pilot system is developed for web visualization of 2D/3D spatial information by implementing basic and application functions for controlling and measuring 3D maps with Graphic User Interface (GUI). For the further research, it is expected that various 2D survey data and various spatial image information of a disaster site can be used for scientific investigation and analysis of disaster accidents by overlaying and visualizing them on a built web-based 3D geo-spatial information system.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.260-265
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• 1999

멀티빔 음향측심기(Multibeam Echo Sounder)는 기존의 단빔 음향측심기(Singlebeam Echo Sounder)와 달리 탐사선 진행방향의 수직(Crosstrack)으로 해저면을 주사(Swath)하여, 한 번의 송수신(Ping)으로 다중의 빔 자료 - 수심, 후방산란된 음압(Backscattered Amplitude), 사이드 스캔 소나(Side Scan Sonar) 자료 - 를 취득하는 장비이다. 멀티빔 음향 측심기를 이용한 해저면 탐사의 경우, 수심이 변함에 따라 주사폭(Swath width)이 변화하고, 각 빔의 수평 해상도(Footprint)는 수심과 더불어 빔폭(Beam width)에 의하여 동적으로 변화한다. 멀티빔 음향 측심기는 해저면을 전역탐사 할 수 있을 뿐만 아니라, 연속된 음향 탐사를 통하여 이웃한 핑 사이에 발생하는 전방중첩영역(Endlap)과 이웃 측선(Trackline)을 따라 겹쳐지는 측방중첩영역(Sidelap)의 자료들을 이용하여 멀티 뎀 자료들의 전반적인 정확도 및 신뢰도를 평가할 수 있다. 본 논문은 수로 측량(Hydrographic Survey)에서 사용되는 멀티빔 음향 측심기를 운영하여 얻어진 측심 자료를 처리하는 알고리즘 개발에 관한 연구이다. 본 논문에서는 L3사의 Sea Beam 2100 벌티빔 음향 측심기를 대상으로, 멀티빔의 측심 원리와 해저 지형에 대한 일반적 이해를 통하여 획득된 측심 자료의 통계적 특성을 파악하고, 오측심된 수심 자료를 제거하는 방법을 제안하며, 측심 구간의 대표격자 크기를 결정하는 기준을 제시한다. 또한, 항공원격탐사에서 고도 추정시 사용되고 있는, 평균보간법, 가중평균 보간법과, 본 논문에서 제안하는 격자 대표값 선정 알고리즘(Gridding Algorithms)의 결과를 비교하고, 최종적으로 얻어지는 해저 수치지형모델(DEM, Digital Elevation Model)과 후방산란 영상을 제시한다. 빠른 한지형잔디들이 지표면을 피복하도록 하고 여름의 고온기와 장마시기에는 뿌리전단력이 우수한 이러한 초종들로 지표면이 피복되도록 하는 것이 이상적이라 생각된다. 4. 혼파처리간의 토사유출량을 비교한 결과 토사 유출 억제효과는 한지형과 나지형잔디들의 혼합형(MixtureIII)과 자생처리구(MixtureV), Italian ryegrass와 자생식물의 혼합형(MixtureIV)등에서 비교적 낮은 수치를 토사유출량을 기록하였다. 이러한 결과는 자생식물들이 비록 초기생육속도는 외래도입초종에 떨어지지만 토사유출의 억제효과면에서는 이들 외래초종에 필적할 수 있음을 나타낸다고 할 수 있겠다.중량이 약 115kg/$m^2$정도로 나타났다.소 들(환경의 의미, 사람의 목적과 지식)보다 미학적 경험에 주는 영향이 큰 것으로 나타났으며, 모든 사람들에게 비슷한 미학적 경험을 발생시키는 것 이 밝혀졌다. 다시 말하면 모든 사람들은 그들의 문화적인 국적과 사회적 인 직업의 차이, 목적의 차이, 또한 환경의 의미의 차이에 상관없이 아름다 운 경관(High-beauty landscape)을 주거지나 나들이 장소로서 선호했으며, 아름답다고 평가했다. 반면에, 사람들이 갖고 있는 문화의 차이, 직업의 차 이, 목적의 차이, 그리고 환경의 의미의 차이에 따라 경관의 미학적 평가가 달라진 것으로 나타났다.corner$적 의도에 의한 경관구성의 일면을 확인할수 있지만 엄밀히 생각하여 보면 이러한 예의 경우도 최락의 총체적인 외형은 마찬가지로 $\ulcorner$순응$\lrcorner$의 범위를 벗어나지 않는다. 그렇기 때문에도 $\ulcorner$순응$\lrcorner$과 $\ulcorner$표현$\lrcorner$의 성격과 형태를 외형상으로 더욱이 공간상에서는 뚜렷하게 경계

• Journal of the Korea Institute of Information and Communication Engineering
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• v.19 no.6
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• pp.1462-1470
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• 2015

The container BIC-code is a transport protocol for convenience in international shipping and combined transport environment. It is an identification code of a marine transport container which displays a wide variety of information including country's code. Recently, transportation through aircrafts and ships continues to rise. Thus fast and accurate processes are required in the ports to manage transportation. Accordingly, in this paper, we propose a BIC-code region extraction and recognition method using multiple thresholds. In the code recognition, applying a fixed threshold is not reasonable due to a variety of illumination conditions caused by change of weather, lightening, camera position, color of the container and so on. Thus, the proposed method selects the best recognition result at the final stage after applying multiple thresholds to recognition. For each threshold, we performs binarization, labeling, BIC-code pattern decision (horizontal or vertical pattern) by morphological close operation, and character separation from the BIC-code. Then, each characters is recognized by template matching. Finally we measure recognition confidence scores for all the thresholds and choose the best one. Experimental results show that the proposed method yields accurate recognition for the container BIC-code with robustness to illumination change.

• Korean Journal of Remote Sensing
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• v.34 no.2_2
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• pp.377-391
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• 2018

In order to efficiently monitor red tide over a wide range, the need for red tide detection using remote sensing is increasing. However, the previous studies focus on the development of red tide detection algorithm for ocean colour sensor. In this study, we propose the use of multi-sensor to improve the inaccuracy for red tide detection and remote sensing data in coastal areas with high turbidity, which are pointed out as limitations of satellite-based red tide monitoring. The study area were selected based on the red tide information provided by National Institute of Fisheries Science, and spatial fusion and spectral-based fusion were attempted using GOCI image as ocean colour sensor and Landsat OLI image as terrestrial sensor. Through spatial fusion of the two images, both the red tide of the coastal area and the outer sea areas, where the quality of Landsat OLI image was low, which were impossible to observe in GOCI images, showed improved detection results. As a result of spectral-based fusion performed by feature-level and rawdata-level, there was no significant difference in red tide distribution patterns derived from the two methods. However, in the feature-level method, the red tide area tends to overestimated as spatial resolution of the image low. As a result of pixel segmentation by linear spectral unmixing method, the difference in the red tide area was found to increase as the number of pixels with low red tide ratio increased. For rawdata-level, Gram-Schmidt sharpening method estimated a somewhat larger area than PC spectral sharpening method, but no significant difference was observed. In this study, it is shown that coastal red tide with high turbidity as well as outer sea areas can be detected through spatial fusion of ocean colour and terrestrial sensor. Also, by presenting various spectral-based fusion methods, more accurate red tide area estimation method is suggested. It is expected that this result will provide more precise detection of red tide around the Korean peninsula and accurate red tide area information needed to determine countermeasure to effectively control red tide.

• Journal of the Korean Association of Geographic Information Studies
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• v.25 no.1
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• pp.133-149
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• 2022

Existing domestic studies on estimating rice yield were mainly implemented at the level of cities and counties in the entire nation using MODIS satellite images with low spatial resolution. Unlike previous studies, this study tried to estimate rice yield at the level of eup-myon-dong in Gimje-si, Jeollabuk-do using Sentinel-2 satellite images with medium spatial resolution, rainfall and soil data, and then to evaluate its accuracy. Five vegetation indices such as NDVI, LAI, EVI2, MCARI1 and MCARI2 derived from Sentinel-2 images of August 1, 2018 for Gimje-si, Jeollabuk-do, rainfall and paddy soil-type data were aggregated by the level of eup-myon-dong and then rice yield was estimated with gamma generalized linear model, an expanded variant of multi-variate regression analysis to solve the non-normality problem of dependent variable. In the rice yield model finally developed, EVI2, rainfall days in September, and saline soils ratio were used as significant independent variables. The coefficient of determination representing the model fit was 0.68 and the RMSE for showing the model accuracy was 62.29kg/10a. This model estimated the total rice production in Gimje-si in 2018 to be 96,914.6M/T, which was very close to 94,470.3M/T the actual amount specified in the Statistical Yearbook with an error of 0.46%. Also, the rice production per unit area of Gimje-si was amounted to 552kg/10a, which was almost consistent with 550kg/10a of the statistical data. This result is similar to that of the previous studies and it demonstrated that the rice yield can be estimated using Sentinel-2 satellite images at the level of cities and counties or smaller districts in Korea.

• Korean Journal of Remote Sensing
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• v.39 no.5_4
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• pp.1135-1144
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• 2023

Many agricultural reservoirs in South Korea, constructed before 1970, have become aging facilities. The majority of small-scale reservoirs lack measurement systems to ascertain basic specifications and water levels, classifying them as unmeasured reservoirs. Furthermore, continuous sedimentation within the reservoirs and industrial development-induced water quality deterioration lead to reduced water supply capacity and changes in reservoir morphology. This study utilized Light Detection And Ranging (LiDAR) sensors, which provide elevation information and allow for the characterization of surface features, to construct high-resolution Digital Surface Model (DSM) and Digital Elevation Model (DEM) data of reservoir facilities. Additionally, bathymetric measurements based on multibeam echosounders were conducted to propose an updated approach for determining reservoir capacity. Drone-based LiDAR was employed to generate DSM and DEM data with a spatial resolution of 50 cm, enabling the display of elevations of hydraulic structures, such as embankments, spillways, and intake channels. Furthermore, using drone-based hyperspectral imagery, Normalized Difference Vegetation Index (NDVI) and Normalized Difference Water Index (NDWI) were calculated to detect water bodies and verify differences from existing reservoir boundaries. The constructed high-resolution DEM data were integrated with bathymetric measurements to create underwater contour maps, which were used to generate a Triangulated Irregular Network (TIN). The TIN was utilized to calculate the inundation area and volume of the reservoir, yielding results highly consistent with basic specifications. Considering areas that were not surveyed due to underwater vegetation, it is anticipated that this data will be valuable for future updates of reservoir capacity information.

• Journal of Chest Surgery
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• v.38 no.6 s.251
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• pp.410-414
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• 2005

There are several options for choosing a graft in CABG, we routinely chose LIMA for LAD and great saphenous vein for other target vessels. To evaluate the posoperative graft patency, we have studied the results using a 16 slices multi-detector computed tomography. Material and Method: From 1995 to 2003, 80 CABG patients who did not complain any event of MACE have been examined by 16-MDCT, mostly in an out patient clinic. Result: There were 61 men and 19 women. MDCT was used as early as 7 days to 9 years post-operatively with a median follow-up period of 6.5 years, and mean follow-up peiod of $31.5\pm25.4$ months. Mean age was $58.4\pm12.6$ years old in men and $61.5\pm17.2$ years old in women. 72180 patients received LIMA to LAD, and all other patients received vein grafts for bypass. The target vessel of vein grafts were 8 in LAD, 47 in RCA, 60 in diagonals, and 61 in obtuse marginals. Among them 42 sequential anastomoses were performed. The mean graft number was $3.1\pm1.8$ grafts. 5 year graft patency rate of each grafts was as followings; $93.1\%$ in LIMA to LAD, $94.9\%$ in vein to diagonals, $92.1\%$ in vein to obtuse marginals, and $79.2\%$ in vein to RCA. Sequential grafting showed better graft patency than the isolated grafting $(95.2\%\;vs\;78.7\~95.0\%)$. Conclusion: In this study, CABG with LIMA and saphenous veins showed satisfactory longterm results. 16-MDCT provided good images for follow-up study after CABG. Additionally, as radiologic tools (64-MDCT, MRI) improve more in the future, they can be used for diagnosing preoperative anatomical coronary disease as well as cardiac functions.