• Journal of the Korean Association of Geographic Information Studies
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• v.12 no.3
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• pp.21-34
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• 2009

Usually in flood flow problems, one-dimensional approach does not provide the required details of complex flow phenomena such as the flow in braided rivers and river junction. In this study, two-dimensional finite element mesh is constructed using DEM and GIS tool, and applied to RMA-2model. The purpose of this study is to investigate the applicability of the two dimensional model in natural rivers and to analyze characteristics of river flow due to the change of cross section. For model calibration, the result of unsteady flow analysis was compared with the observed data. Accordingly, the SMS model in this study prove to be very effective and reliable tool for the simulation of hydrodynamic characteristics under the various flow conditions.

• Proceedings of the KIEE Conference
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• 1999.07e
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• pp.2274-2276
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• 1999

In this work, temperature rise and eddy current distribution on the enclosure and conductor of 3 pole gas insulated switchgear were investigated using analytical and experimental measures. The design of the diameters of the conductors and the enclosures of a meal clad gas insulated switchgear is primarily based on the insulation requirements. It is very difficult problem to predict the temperature rise of enclosed switchgear due to the complexity of the phenomena of heat transfer and existence of eddy current loss. To overcome this situations, we focused on the eddy current distribution on the enclosure of switchgear caused by high current 3 pole conductor as a fundamental basis. The experimental results about temperature distribution of 3 pole gas insulated switchgear were reported and measurements are compared with predictions of three-dimensional thermal model for eddy current analysis. As a result, three dimensional numerical analysis found to be in close relationship with experimental results and thermal model is efficient to predict the abnormal temperature rise in switchgear.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2007.04a
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• pp.93-96
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• 2007

LIDAR is a relatively new technological tool that can be used to accurately georeference terrain features, and also is becoming an important 3D mapping tool in GIS. In this study it is described the capabilities of terrestrial LIDAR that was used to build a 3D terrain model of extremely steep rock face, along with the useful data and examples of contributions terrestrial lidar has made to outcrop studies. For this, High-resolution terrestrial lidar acquisition, processing, interpretation are discussed and applied to mapping of geological surfaces in three dimensions. We expected that lidar is a tool with which we can improve our current field methods and quantify the observations geologists make.

• The Transactions of the Korea Information Processing Society
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• v.3 no.1
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• pp.144-152
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• 1996

Recently, as the demands for radio spectrum are growing and the number of cell sites is increasing rapidly, the spectrum engineering plays an important role in estimating frequency sharing and reuse. The radio propagation analysis is essential in the basic technology of radio network design such as deciding the service area and selecting the position of the base station. But, domestic propagation environment in which mountainous region is occupying over 70% of our terrain does not allow us to apply foreign studies which are deduced in highly different environments. Therefore, we need to have our propagation analysis system derived from our own terrain condition. In this paper, we propose the propagation prediction model which issuitable toour propagation environment, and also usinghis model, we implement thesimulator based on GIS(Geographic Information System)which can be applied to both spectrum engineering and radio propagation analysis. We showed that this simulator can well be applied to frequency assignment, propagation network design as well as other radio services. Considering the results of our analysis, we could guarantee the standard deviation of error between the measured data and predicted results as 5 to 7 dB.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.2
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• pp.117-131
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• 2007

Representation of building internal space is an active research area as the need for more geometrically accurate and visually realistic increases. 3 dimensional representation is common ground of research for disciplines such as computer graphics, architectural design and engineering and Geographic Information System (GIS). In many cases CAD plans are the starting point of reconstruction of 3D building models. The main objectives of building reconstruction in GIS applications are visualization and spatial analysis. Hence, CAD plans need to be preprocessed and edited to adapt to the data models of GIS SW and then georeferenced to enable spatial analysis. This study automated the preprocessing of CAD data using AutoCAD VBA (Visual Basic Application), and the processed data was topologically restructured for further analysis in GIS environment. Accuracy of georeferencing CAD data was also examined by comparing the results of coordinate transformation by using digital maps and GPS measurements as the sources of ground control points. The reconstructed buildings were then applied to visualization and network modeling.

• Proceedings of the KSRS Conference
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• v.2
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• pp.586-589
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• 2006

High resolution satellite imagery is regarded as one of the important data sets to engineering application, as well as conventional scientific application. However, despite this general view, there are a few target applications using this information. In this study, the possibility for the future wide uses in associated with smart graphics of this information is investigated. The concept of smart graphics can be termed intelligent graphics with XML-based structure and knowledge related to semantic web, which is a useful component for the data dissemination framework model in a multi-layered web-based application. In the first step in this study, high resolution imagery is transformed to GML (Geographic Markup Language)-based structure with attribute schema and geo-references. In the second, this information is linked with GIS data sets, and this fused data set is represented in the X3D (eXtensible 3D), ISO-based web 3D graphic standard, with styling attributes, in the next stop. The main advantages of this approach using GML and X3D are the flourished representations of a source data according to user/clients’ needs and structured 3D visualization linked with other XML-based application. As for the demonstration of this scheme, 3D urban modelling case with actual data sets is presented.

• Korean Journal of Remote Sensing
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• v.21 no.3
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• pp.229-242
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• 2005

Photogrammetry is a current method of GIS data acquisition. However, as a matter of fact, a large manpower and expenditure for making detailed 3D spatial information is required especially in urban areas where various buildings exist. There are no photogrammetric systems which can automate a process of spatial information acquisition completely. On the other hand, LiDAR has high potential of automating 3D spatial data acquisition because it can directly measure 3D coordinates of objects, but it is rather difficult to recognize the object with only LiDAR data, for its low resolution at this moment. With this background, we believe that it is very advantageous to integrate LiDAR data and stereo CCD images for more efficient and automated acquisition of the 3D spatial data with higher resolution. In this research, the automatic urban object recognition methodology was proposed by integrating ultra highresolution stereo images and LiDAR data. Moreover, a method to enable more reliable and detailed stereo matching method for CCD images was examined by using LiDAR data as an initial 3D data to determine the search range and to detect possibility of occlusions. Finally, intellectual DSMs, which were identified urban features with high resolution, were generated with high speed processing.

• Proceedings of the KSRS Conference
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• 2007.03a
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• pp.97-102
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• 2007

3차원 공간정보는 2차원에 비해 공간적 현실감이 뛰어나기 때문에 최근 경관분석，도시 계획 및 웹(Web) 을 통한 지도 서비스 분야 등에서 이에 대한 관심이 증가하고 있으나，3차원 공간 정보의 기하학적 특성상 기존의 2차원 공간정보에 비해 데이터 량이 방대해 지고 있으며 이를 활용한 또 다른 콘텐츠 제작과 빠르고 효율적인 처리에 많은 문제점을 가지고 있다. 본 논문에서는 이러한 문제점을 해결하기 위한 방법으로 위성 및 항공으로부터 획득한 DEM(Digital Elevation Model)을 이용하여 생성된 3차 원의 지형정보와 도시 모델링 및 텍스처 맵핑 과정을 통해 획득한 정보를 기반으로 하여 각각의 위치에 카메라를 설정하고， 설정된 카메라 위치를 기반으로 Camera Matrix를 구한다. 이렇게 획득한 카메라의 정보엔 깊이 정보를 포함하고 있는데，깊이 정보를 기반으로 하여 3차원의 워핑(Warping)작업을 통해 계층적 핍이 영상(LDI)를 생성하고，생성된 계층적 깊이 영상을 이용하여 3차원의 공간정보를 구현한다.

• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2003.10a
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• pp.245-250
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• 2003

Digital Elevation Model(DEM) is basic spatial information used in various GIS areas such as spatial analysis, 3D modeling, etc. In particular, DEM of road inclined plane is need for the plan, design, construction and maintenance of social infrastructures such as roads and bridges in construction technology, one of GIS application. However, generating DEM of road inclined plane with high accuracy is very difficult. Therefore, the purpose of this study is to propose how to generate road DEM with high accuracy through extracting road inclined plane automatically using Laser scanning data.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.06a
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• pp.387-390
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• 2008

소음지도는 공간의 소음값을 3차원적으로 분석하여 GIS 데이터에 소음분석결과값을 RGB 값으로 표현한 것이다. 현재의 GIS는 2차원 데이터이므로 3차원 소음분석결과값을 표현하고 사용자들에게 제공하는 것에 효과적이지 못하다. 따라서 본 연구에서는 소음분석결과값을 보다 효과적으로 사용자들에게 제공하기 위하여 3차원 소음지도를 제작하고자 한다. 3차원 소음지도는 도시공간모델의 지형과 건물을 각각 소음분석결과값을 이용하여 texturing하여 가시화한 후 통합하여 완성한다. 지형의 경우, 지형의 기하학적 가시화완 지형의 texturing의 두 단계를 거쳐 완성하고 건물의 경우, 건물의 기하학적 3차원 가시화와 건물의 texturing의 두 단계를 거쳐 생성한다. 건물과 지형의 texturing의 단계에서 texture file은 소음분석결과값을 RGB코드로 변환하여 jpg파일로 생성한다. 생성된 3차원 소음지도는 영등포구 전체 영역을 대상지로 하였고 web기반의 VRML파일이다. 가시화의 효율성을 고려하여 영등포구 영역을 $200m{\times}200m$로 구역을 설정 607개의 구역으로 나누어 가시화하였다. 도시공간 모델을 이용하여 3차원 소음지도를 제작함으로써 도시공간모델을 이용하는 응용분야에서 3차원 공간분석의 가시화를 위한 방법을 제시할 수 있었다. 이를 통하여 공간 문제들의 결과를 사용자들에게 보다 효율적으로 제공할 수 있을 것이다.