• Journal of Cadastre & Land InformatiX
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• v.52 no.1
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• pp.69-80
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• 2022

Drone photogrammetry generally acquires images vertically or obliquely from above, so when photographing for the purpose of three-dimensional modeling, image matching for the ground of a building and spatial accuracy of point cloud data are poor, resulting in poor 3D mesh completeness. Therefore, to overcome this, this study analyzed the spatial accuracy of each drone image by acquiring smartphone images from the ground, and evaluated the accuracy improvement and completeness of 3D mesh when the smartphone image is not combined with the drone image. As a result of the study, the horizontal (x,y) accuracy of drone photogrammetry was about 1/200,000, similar to that of traditional photogrammetry. In addition, it was analyzed that the accuracy according to the photographing method was more affected by the photographing angle of the object than the increase in the number of photos. In the case of the smartphone image combination, the accuracy was not significantly affected, but the completeness of the 3D mesh was able to obtain a 3D mesh of about LoD3 that satisfies the digital twin city standard. Therefore, it is judged that it can be sufficiently used to build a 3D model for digital twin city by combining drone images and smartphones or DSLR images taken on the ground.

• Journal of the Korean earth science society
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• v.41 no.2
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• pp.111-128
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• 2020

This study presents a possibility of intensification of fine dust mass concentration due to the complex urban structure using data mining technique and clustering analysis. The data mining technique showed no significant correlation between fine dust concentration and regional-use public urban data over Seoul. However, clustering analysis based on nationwide-use public data showed that building heights (floors) have a strong correlation particularly with PM₁₀. The modeling analyses using the single canopy model and the micro-atmospheric modeling program (ENVI-Met. 4) conducted that the controlled atmospheric convection in urban area leaded to the congested flow pattern depending on the building along the distribution and height. The complex structure of urban building controls convective activity resulted in stagnation condition and fine dust increase near the surface. Consequently, the residual effect through the changes in the thermal environment caused by the shape and structure of the urban buildings must be considered in the fine dust distribution. It is notable that the atmospheric congestion may be misidentified as an important implications for providing information about the residual probability of fine dust mass concentration in the complex urban area.

• Proceedings of the Korea Contents Association Conference
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• 2005.11a
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• pp.335-339
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• 2005

Digital elevation models(DEM) were generated from SPOT-5 HRG supermode imagery through photogrammetric processing. The reference DEMs were obtained from digital topographic maps of 1/5000 scaleas for analyzing the accuracy of the generated DEMs. The DEMs extracted from HRG stereo image data were compared with digital topograpic map DEMs on several test sections. And digital surface models(DSM) and 3D building model was produced.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2004.10a
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• pp.13-18
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• 2004

In this study, a new method is proposed generating 3D wire-frames of building using the lowest level topology, points, which are input by human operators. Through the procedure, it is possible to make prediction occlusion points and generate the topology automatically among points, lines, surfaces from buildings. In order to adjust the error of initial values which are input manually, the least squares adjustment for model-image fitting is carried out using the edge information of aerial imagery. And also, model fitting procedure is done making all surfaces plane of buildings by the least squares adjustment. As a result of those procedure, 3D building models are refined similar to real figures of buildings.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.23 no.10
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• pp.687-698
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• 2011

In this study, it was analyzed by a numerical analysis that plan/design considerations for ensuring the spectator safety of large arena audiences in a fire emergency evacuation plan. The latest issue, the 'performance-based design', fire and evacuation plan is important. But nowadays 'Specification-based design' is in common. In evacuation simulation, congestion of exit and aisle is ignored because only evacuation time of large-space is mainly analyzed. In smoke flow,'smoke filling effect' tends to be overrated. From now on, when design a field house, it is needed not 'smoke filling effect' and 'large-space evacuation' analysis, but analyzing 'whole building evacuation time' for ensuring fire evacuation safety of spectator.

• Proceedings of the Korea Water Resources Association Conference
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• 2020.06a
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• pp.403-403
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• 2020

국외에서 잘 알려진 Hazus-MH, RiskScape와 같은 자연재난 리스크 모델은 위험지역 내 노출된 자산과 인구의 공간적 분포 및 그 특성을 설명하는 지형공간자료 형태의 자산정보(인벤토리)를 필요로 한다. 본 연구는 이러한 자연재난 리스크 모델 운용에 필요한 건물, 인구, 농업, 차량 인벤토리 데이터 구조를 국내에서 가용가능한 자료를 기반으로 설계하고, 이들을 연계, 변환하기 위한 툴을 개발하였다. 본 연구에서 개발된 자동변환 툴은 오픈소스로 제공되는 QGIS를 기반으로 하였고, 개발 툴을 이용하여 2018년 말 기준의 인벤토리를 전국에 대해 구축하였다. 본 연구의 성과는 현재 시범운용 중인 행정안전부 풍수해 피해예측시스템을 비롯한 자연재난 리스크 모델링 과정에 활용될 것으로 기대된다.

• Journal of the Korean Association of Geographic Information Studies
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• v.21 no.4
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• pp.26-49
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• 2018

The purpose of this study was to verify the reliability of the solar radiation model and discuss its applicability to the urban area of Seoul for summer heat stress mitigation. We extended the study area closer to the city scale and enhanced the spatial resolution sufficiently to determine pedestrian-level urban radiance. The domain was a $4km^2$ residential area with high-rise building sites. Radiance modelling (SOLWEIG) was performed with LiDAR (Light Detection and Ranging)-based detailed geomorphological land cover shape. The radiance model was evaluated using surface energy balance (SEB) observations. The model showed the highest accuracy on a clear day in summer. When the mean radiation temperature (MRT) was simulated, the highest value was for a low-rise building area and road surface with a low shadow effect. On the other hand, for high-rise buildings and vegetated areas, the effect of shadows was large and showed a relatively low value of mean radiation temperature. The method proposed in this study exhibits high reliability for the management of heat stress in urban areas at pedestrian height. It is applicable for many urban micro-climate management functions related to natural and artificial urban settings; for example, when a new urban infrastructure is planned.

• Spatial Information Research
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• v.20 no.6
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• pp.99-107
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• 2012

Recently, various researches have been attempted to connect or integrate BIM handling construction data and GIS handling spatial data. However, it is hard to interoperate by integration between two data models because characteristics and domains of data models between BIM and GIS are very different. In this research, we propose the platform to secure efficient interoperability between BIM and GIS and define the component technologies and functions of the platform proposed in this research by analyzing the existing commercial softwares.

• Journal of Korean Society for Geospatial Information Science
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• v.15 no.1 s.39
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• pp.67-73
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• 2007

Recently, three-dimensional (3D) GI (Geospatial Information) using LiDAR system has been used various fields such as the production of digital map, the modeling of 3D building and urban area, and analysis of communication network and environmental effect. In this study, the production cost of digital map by aerial LiDAR surveying were compared with the cost by aerial photograph surveying for analysis of economical efficiency. It is expected that the results of this study will be used base data for production, update, revision of digital map and curtail effect of national budget.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.18 no.1
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• pp.51-57
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• 2000

With the emergence of laser mapping systems, higher resolution DTM of urban area can be acquired and can be used to generate precise orthoimage. But, when the conventional orthoimage generation methods are applied to the area containing features with height difference such as cliffs, bridges, banks. elevated highways and buildings, they cause problems such as occlusion and double mapping. Therefore, this study proposes a new algorithm by modifying and refining conventional orthoimage generation methods. With this algorithm, areas which have occlusion are detected from the base image using camera orientation parameters and DTM. Also, detected areas are restored using alternative images which does not have occlusion in that area. This study can be distinguished from the other studies in the aspects that the proposed algorithm in this paper doesn't need information on building and that uses DTM data and orientation parameters.