• Proceedings of the Korean Information Science Society Conference
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• 2000.10a
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• pp.68-70
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• 2000

최근 웹을 통하여 지리정보를 제공하는 서비스가 점점 보편화되어 가고 있다. 그러나 대부분의 서비스는 서버에서 모든 질의를 처리하고 결과를 이미지형태로 보여주는 구조를 가지고 있어 서버에 많은 부담을 주고 제공할 수 있는 서비스에 제약이 있다. 벡터데이터 기반 서비스의 경우 이러한 문제를 해결할 수 있으나 상대적으로 높은 클라이언트 성능을 요구한다. 그러나 최근 클라이언트 시스템의 성능이 향상됨에 따라 벡터데이터를 사용하여 클라이언트측의 자원을 사용하는 구조가 의미있게 되었다. 본 논문은 벡터데이터를 기반으로 하여 웹을 통해 지리 정보를 제공하는 시스템을 설계하고 구현하였다. 사용자에게 불필요한 정보를 제거하고 데이터 전송량을 줄이기 위하여 레벨에 따른 상세정도(LOD: Level of Detail)를 지원하고, 클라이언트 캐시, 데이터 압축 전송 등의 방법을 사용한다. 또한, 객체전송을 위한 통신모듈을 자동으로 생성해주는 툴을 사용하여 개발시간을 줄이도록 하였다.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2011.04a
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• pp.235-238
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• 2011

본 연구에서는 필요한 수준의 성과품 납품을 위해 교량정보모델의 상세수준을 분류하고 각 상세수준에서 요구되는 세부정보를 분석하였다. 이는 기본적으로 교량 설계 업무가 단계별로 이루어지며 각 단계마다 성과품을 납품하도록 규정 되어있다는 사실을 바탕으로 연구가 이루어졌다. 이를 위하여 본 연구에서는 우선, 국내의 교량 설계준공단계 성과품 납품 항목 중 교량정보모델에 요구되는 항목을 분류하였으며 분류한 요구항목에 맞춰 3D객체와 속성정보수준을 정하여 업무 프로세스 단계별 상세수준을 정의하였다. 또한, 정의한 상세수준을 기준으로 하여 각 상세수준에서 포함하도록 요구되는 세부정보 분석을 수행하였으며, 분석된 세부요구정보는 성과품 납품에 활용가능하다.

• Proceedings of the Korea Multimedia Society Conference
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• 2001.11a
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• pp.171-176
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• 2001

3차일 CIS 소프트웨어를 개발하기 위한 기술로는 공간데이터처리 및 공간분석기술, 컴퓨터그래픽스 및 가상현실 기술에 이르기까지 다양한 연구가 요구된다. 지리정보 가시화(visualization)에 관한 연구는 여러 GIS 응용분야에서 주요한 부분이 된다. 현재 2차원 기 구축된 데이터를 이용하여 3차원으로 가시화 및 분석을 수행할 수 있다는 것은 데이터와 소프트웨어 재사용 및 비용측면에서 중요한 의미를 가진다. 본 논문에서는 한국전자통신연구원에서 개발한 Mapbase 컴포넌트에서 빌딩 레이어 3차원 모델링 방법과 시설물의 다양한 상세도 제어가 가능한 LOD(level-of-detail) 모델러와 3차원 데이터와 최소한의 3차원 부가정보(빌딩높이, 도로폭등)를 이용하여 규칙기반 모델링(Rule-Based Modeling)을 통해 3차원으로 모델링 해낼 수 있는 3차원 장면 모델러 컴포넌트 설계방안을 제안한다. 장면 모델러 컴포넌트 분석을 위해 처리하는 이력 데이터, 수작업 3차원 모델링 여부, 소프트웨어 재사용성, 상호운용성, 구축 비용 등을 기준으로 분석하였다.

• 한국HCI학회:학술대회논문집
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• 2007.02a
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• pp.694-699
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• 2007

2D에서 3D로 이동하고 있는 현재의 GIS는 자료 크기가 기하급수적으로 커지고 이로 인해 처리속도가 느려지고 있으며 사용자의 실시간 렌더링(Rendering) 욕구는 커지고 있다. 대용량의 공간자료에 대한 처리속도, 3차원 처리기술, 가상현실 처리기술 등의 제약조건과 함께 3차원 GIS를 가시화하기 위해서는 방대한 데이터를 처리하기 위한 시간과 비용이 많이 과다하게 발생하는 문제점을 가지고 있다. 본 논문에서는 이러한 문제를 해결하기 위해 위성 및 항공으로부터 획득된 DEM 데이터를 이용하여 VRML로 가시화하여 3차원의 지형 정보를 생성하였다. 이렇게 생성된 지형 데이터에 LOD(Level of Detail) 기법을 통한 단순화 과정을 거쳐 3차원의 지형정보를 획득하고, 수치지도를 기반으로 한 모델링 및 텍스처 맵핑 과정을 통해 3차원의 도시 정보를 획득하게 된다. 이렇게 획득된 도시 정보에 3차원 공간적인 조건 및 검색을 가능하게 함으로써 언제 어디서든 누구나 쉽게 건물 및 도로에 대한 정보를 검색할 수 있도록 하였고, 네비게이션 및 시뮬레이션 기능을 추가한 웹 기반의 3차원 가상 도시를 구현하였다.

• Journal of the Korea Computer Graphics Society
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• v.6 no.4
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• pp.1-7
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• 2000

Traditionally, three dimension model s have been used for building virtual worlds, and a data structure called the "scene graph" is often employed to organize these 3D objects in the virtual space. On the other hand, image-based rendering has recently been suggested as a probable alternative VR platform for its photo-realism, however, due to limited interactivity. it has only been used for simple navigation systems. To combine the merits of these two approaches to object/scene representations, this paper proposes for a scene graph structure in which both 3D models and various image-based scenes/objects can be defined. traversed, and rendered together. In fact, as suggested by Shade et al. [1]. these different representations can be used as different LOD's for a given object. For in stance, an object might be rendered using a 3D model at close range, a billboard at an intermediate range. and as part of an environment map at far range. The ultimate objective of this mixed platform is to breath more interactivity into the image based rendered VE's by employing 3D models as well. There are several technical challenges in devising such a platform : designing scene graph nodes for various types of image based techniques, establishing criteria for LOD/representation selection. handling their transition s. implementing appropriate interaction schemes. and correctly rendering the overall scene. Currently, we have extended the scene graph structure of the Sense8's WorldToolKit. to accommodate new node types for environment maps. billboards, moving textures and sprites, "Tour-into-the-Picture" structure, and view interpolated objects. As for choosing the right LOD level, the usual viewing distance and image space criteria are used, however, the switching between the image and 3D model occurs at a distance from the user where the user starts to perceive the object's internal depth. Also. during interaction, regardless of the viewing distance. a 3D representation would be used, if it exists. Finally. we carried out experiments to verify the theoretical derivation of the switching rule and obtained positive results.

• Journal of the Korean Association of Geographic Information Studies
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• v.23 no.3
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• pp.146-160
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• 2020

In the 4th industrial revolution, research on solving urban problems using ICT technology is emerging. Representatively, research is being conducted mainly focusing on smart cities. 3D geo-spatial. Various case studies on smart cities are being conducted to solve urban problems, and in order to effectively implement smart cities, it is implemented on the basis of a digital twin interconnecting physical and virtual environments. To implement a digital twin, the concept of space is essential, and spatial information that composes the real world is also essential. Therefore, in order to implement the digital twin, this study conducted a study on the construction and modeling of 3D geo-spatial information based on the national spatial information establishment regulations and the international standard CityGML for buildings, water facilities, and transportation facilities in Jeonju. In Jeonju, the research area, the LOD was defined, and the possibility of digital twin based on geo-spatial information was determined through data collection, analysis, and construction for each detail. In this study, it is meaningful that a plan to construct geo-spatial information for the implementation of a digital twin is presented, and the result of the construction is modeled as an urban standard model. The results of study are expected to be used as reference for detailed construction plans and standard establishment by governments and local governments promoting smart city and digital twin construction in the future.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.2
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• pp.141-151
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• 2020

Since it was first studied in 1980, solar energy analysis model for geographic information systems has been used to determine the approximate spatial distribution of terrain. However, the spatial pattern was not able to be grasped in 3D (three-dimensional) space with low accuracy due to the limitation of input data. Because of computational efficiency, using a constant value for the brightness of the sky caused the simulation results to be less reliable especially when the slope is high or buildings are crowded around. For the above reasons, this study proposed a model that predicts solar energy of vertical surfaces of buildings with four stages below. Firstly, CIE (Commission Internationale de l'Eclairage) luminance distribution model was used to calculate the brightness distribution of the sky using NREL (National Renewable Energy Laboratory) solar tracking algorithm. Secondly, we suggested a method of calculating the shadow effect using ray tracing. Thirdly, LOD (Level of Detail) 3 of 3D spatial data was used as input data for analysis. Lastly, the accuracy was evaluated based on the atmospheric radiation data collected through the ground observation equipment in Daejeon, South Korea. As a result of evaluating the accuracy, NMBE was 5.14%, RMSE 11.12, and CVRMSE 7.09%.

• Journal of the Society of Naval Architects of Korea
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• v.51 no.3
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• pp.203-211
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• 2014

To raise the industrial competitiveness in the field of ship-building, it is crucially important that the yard should use production facilities and working space effectively. Among the related works, the management of tremendous blocks' number, the limited area of assembly shops and inefficient personnel and facility management still need to be improved in terms of being exposed to a lot of problems. To settle down these conundrums, the various strategies of block arrangement on the assembly floors have been recently presented and in the results, have increasingly began to be utilized in practice. However, it is a wonder that the sampled or approximated block shapes which usually are standardized projections or the geometrically convex contour only have been prevailed until now. In this study, all parts including the panel, stiffeners, outer shells, and all kinds of outfitting equipment are first extracted using the Volume Primitive plug-in module from the ship customized CAD system and then, the presented system constructs a simpler and more compact ship data structure and finally generates the novel projected contours for the block arrangement system using the adaptive concave hull algorithm.

• Journal of KIBIM
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• v.12 no.3
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• pp.1-17
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• 2022

As the technology of Smart City and Digital Twin is developing, techniques to integrate BIM data of infrastructure facilities into GIS are becoming more critical. Hence, this study aims to manage BIM data representing bridge and tunnel structures through the Industry Foundation Classes (IFC) standard and to develop a method to link these IFC-compliant files to the GIS standard CityGML without loss of information. We analyze the criteria for creating BIM data for bridges and tunnels by reviewing the BIM guidelines set by each client. We use these criteria to suggest methods for data management based on InfraBIM as a specific IFC class standard. Furthermore, we perform model analysis to determine the necessary design and construction field-appropriate model process and Level of Detail (LOD). From the model analysis, we conclude that the classified BIM models can be used as base data to generate BIM models of bridges and tunnels for facility management.

• Korean Journal of Computational Design and Engineering
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• v.9 no.2
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• pp.122-132
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• 2004

Progressive mesh representation and generation have become one of the most important issues in network-based computer graphics. However, current researches are mostly focused on triangular mesh models. On the other hand, solid models are widely used in industry and are applied to advanced applications such as product design and virtual assembly. Moreover, as the demand to share and transmit these solid models over the network is emerging, the generation and the transmission of progressive solid models depending on specific engineering needs and purpose are essential. In this paper, we present a Cellular Topology-based approach to generating and transmitting progressive solid models from a feature-based solid model for internet-based design and collaboration. The proposed approach introduces a new scheme for storing and transmitting solid models over the network. The Cellular Topology (CT) approach makes it possible to effectively generate progressive solid models and to efficiently transmit the models over the network with compact model size. Thus, an arbitrary solid model SM designed by a set of design features is stored as a much coarser solid model SM/sup 0/ together with a sequence of n detail records that indicate how to incrementally refine SM/sup 0/ exactly back into the original solid model SM = SM/sup 0/.