• Proceedings of the Korean Society of Surveying, Geodesy, Photogrammetry, and Cartography Conference
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• 2006.04a
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• pp.469-473
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• 2006

In general, a classification process between ground data and non-ground data, which include building objects, is required prior to producing a DEM for a certain surface reconstruction from LiDAR data in which the DEM can be produced from the ground data, and certain objects like buildings can be reconstructed using non-ground data. Thus, an exact classification between ground and non-ground data from LiDAR data is the most important factor in the ground reconstruction process using LiDAR data. In particular, building objects can be largely used as digital maps, orthophotos, and urban planning regarding the object in the ground and become an essential to providing three dimensional information for certain urban areas. In this study, an entropy theory, which has been used as a standard of disorder or uncertainty for data used in the information theory, is used to apply a more objective and generalized method in the recognition and segmentation of buildings from raw LiDAR data. In particular, a method that directly uses the raw LiDAR data, which is a type of point shape vector data, without any changes, to a type of normal lattices was proposed, and the existing algorithm that segments LiDAR data into ground and non-ground data as a binarization manner was improved. In addition, this study proposes a generalized building extraction method that excludes precedent information for buildings and topographies and subsidiary materials, which have different data sources.

• Proceedings of the KIEE Conference
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• 2006.10c
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• pp.536-538
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• 2006

The most important factor of mobile robot is to build a map for surrounding environment and estimate its localization. This paper proposes a real-time localization and map building method through 3-D reconstruction using scale invariant feature from monocular camera. Mobile robot attached monocular camera looking wall extracts scale invariant features in each image using SIFT(Scale Invariant Feature Transform) as it follows wall. Matching is carried out by the extracted features and matching feature map that is transformed into absolute coordinates using 3-D reconstruction of point and geometrical analysis of surrounding environment build, and store it map database. After finished feature map building, the robot finds some points matched with previous feature map and find its pose by affine parameter in real time. Position error of the proposed method was maximum. 8cm and angle error was within $10^{\circ}$.

• Journal of architectural history
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• v.29 no.2
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• pp.63-74
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• 2020

The palace byeoljeon(別殿), the King's non-ceremonial space, were created as a space for the king to comfortably use and for the king to do what he wanted to do. The byeoljeon housed various types of spaces and were flexible in that they could be repurposed to meet the demands of the times. Nevertheless, their characteristic as palatial building created for the King's convenience has remained unchanged. In this study, we examine the process by which such royal spaces were created by focusing on the reconstruction of the Changdeokgung Huijeongdang during Japanese occupation period, with a view to continuity and the transformation process. The reconstruction of Huijeongdang at the time may be considered along internal and external characteristics. Internally, Huijeongdang connected the symbolism of the king's space as the palace byeoljeon. Externally, Huijeongdang is characterized by its mixture of traditional and western style, where western style structures were housed within traditional buildings. The plans for the block of Huijeongdang also included the coexistence of traditional building, western style building, and mixture of traditional and western style building. This reflects the characteristic continuity of the byeoljeon as well as the architectural techniques of the time, manifested together within a specific spatial block.

• Advances in Computational Design
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• v.4 no.2
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• pp.155-177
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• 2019

Operation and Maintenance (O&M) phase is the main contributor to the total lifecycle cost of a building. Previous studies have described that Building Information Models (BIM), if available with detailed asset information and their properties, can enable rapid troubleshooting and execution of O&M tasks by providing the required information of the facility. Despite the potential benefits, there is still rarely BIM with Mechanical, Electrical and Plumbing (MEP) assets and properties that are available for O&M. BIM is usually not in possession for existing buildings and generating BIM manually is a time-consuming process. Hence, there is a need for an automated approach that can reconstruct the MEP systems in BIM. Previous studies investigated automatic reconstruction of BIM using architectural drawings, structural drawings, or the combination with photos. But most of the previous studies are limited to reconstruct the architectural and structural components. Note that mechanical components in the building typically require more frequent maintenance than architectural or structural components. However, the building mechanical drawings are relatively more complex due to various type of symbols that are used to represent the mechanical systems. In order to address this challenge, this paper proposed a symbol recognition framework that can automatically recognize the different type of symbols in the building mechanical drawings. This study applied vector-based computer vision techniques to recognize the symbols and their properties (e.g., location, type, etc.) in two vector-based input documents: 2D drawings and the symbol description document. The framework not only enables recognizing and locating the mechanical component of interest for BIM reconstruction purpose but opens the possibility of merging the updated information into the current BIM in the future reducing the time of repeated manual creation of BIM after every renovation project.

• The Transactions of the Korean Institute of Electrical Engineers D
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• v.55 no.4
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• pp.173-180
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• 2006

A key component of autonomous navigation of intelligent home robot is localization and map building with recognized features from the environment. To validate this, accurate measurement of relative location between robot and features is essential. In this paper, we proposed relative localization algorithm based on 3D reconstruction of scale invariant features of two images which are captured from two parallel cameras. We captured two images from parallel cameras which are attached in front of robot and detect scale invariant features in each image using SIFT(scale invariant feature transform). Then, we performed matching for the two image's feature points and got the relative location using 3D reconstruction for the matched points. Stereo camera needs high precision of two camera's extrinsic and matching pixels in two camera image. Because we used two cameras which are different from stereo camera and scale invariant feature point and it's easy to setup the extrinsic parameter. Furthermore, 3D reconstruction does not need any other sensor. And the results can be simultaneously used by obstacle avoidance, map building and localization. We set 20cm the distance between two camera and capture the 3frames per second. The experimental results show :t6cm maximum error in the range of less than 2m and ${\pm}15cm$ maximum error in the range of between 2m and 4m.

• Journal of Broadcast Engineering
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• v.21 no.1
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• pp.3-10
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• 2016

In this paper, two reconstructed point cloud sets with the information of 3D features are analyzed. For a certain 3D reconstruction of the interior of a building, the first image set is taken from the sequential passive camera movement along the regular grid path and the second set is from the application of the laser scanning process. Matched key points over all images are obtained by the SIFT(Scale Invariant Feature Transformation) algorithm and are used for the registration of the point cloud data. The obtained results are point cloud number, average density of point cloud and the generating time for point cloud. Experimental results show the necessity of images from the additional sensors as well as the images from the camera for the more accurate 3D reconstruction of the interior of a building.

• Journal of architectural history
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• v.24 no.4
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• pp.7-18
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• 2015

Gwanghwamun was dismantled and displaced to the east side of the palace, at that time, the Chosun Government General Building was constructed in the Gyeongbokgung palace. After the Korea war, it remained as a stonework as a result of the fire. In 1968, The Gwanghwamun came back in front of the palace. Then, why it was rebuilt in the 3rd Republic period? What was the reason for selecting concrete? Since the May 16 coup, the military regime had been utilized palace and surrounding urban space to show a visible practice of modernization. Attempting the combination of modern technology in the 1960s and traditional cultural property and reconstructing a city as a pretext called Cultural Heritage conservation was a typical mechanism of the 1960s. In this study, I start by assume that reconstructing Gwanghwamun(1968) was a part of project to change the surrounding urban space of Gwanghwamun than to preserve cultural assets. Two main contributions of the study are following. First, I collect availabe data on the reconstructing surrounding urban space of the Gwanghwamun and re-organize them in chronological order to make them as fragments of a map. Second, I analysis and identify the nature and phase of the Gwanghwamun reconstruction.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2005.11a
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• pp.141-148
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• 2005

This study as a demand of reconstruction allows the longevity of the multi complex, analyze the problems and solutions for a long term maintenance planning scheme, and how to save contingency fund to utilize. The major role of the multi complex housing market reflects Positively on our valuable society, provides a better life of environment on top of longevity and for the superior living duality. For a achievement and improvement existing long term maintenance Plan and contingency fund system should be considered as follows. First, shall be expanded more units of house as smaller group. Second, advice from expert shall be reconsidered, eliminated, and protected reorganizing an informal reconstruction planning comparatively legal procedure must be renegotiated and pursued. Third, the fund which saved for the contingency has to clarified as tax free item by government. It's not only mistreated as a limitation of personal asset but also treated as national source Despite of rather compulsive and constructive method must be noticed by whoever owns for, more positive follows, promotion and directing must be able to guide its understanding and adherence of importance and inevitability.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2003.05a
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• pp.119-124
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• 2003

Lately Construction industry tends to prefer remodeling of existing building rather then new construction or reconstruction of buildings due to strengthening of several restriction related to real estates along with prolonged depression. Specially in case of Apartment houses, since vagueness on ownership and management authority on common part exists. So in this study we are to present the procedure of analyzing apartment house remodeling method through user request by approaching to several considerable factors in user request side.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.25 no.6_1
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• pp.545-555
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• 2007

3D buildings are the most prominent feature comprising urban scene. A few of mega-cities in the globe are virtually reconstructed in photo-realistic 3D models, which becomes accessible by the public through the state-of-the-art online mapping services. A lot of research efforts have been made to develop automatic reconstruction technique of large-scale 3D building models from remotely sensed data. However, existing methods still produce irregular building polygons due to errors induced partly by uncalibrated sensor system, scene complexity and partly inappropriate sensor resolution to observed object scales. Thus, a geometric regularization technique is urgently required to rectify such irregular building polygons that are quickly captured from low sensory data. This paper aims to develop a new method for regularizing noise building outlines extracted from airborne LiDAR data, and to evaluate its performance in comparison with existing methods. These include Douglas-Peucker's polyline simplication, total least-squared adjustment, model hypothesis-verification, and rule-based rectification. Based on Minimum Description Length (MDL) principal, a new objective function, Geometric Minimum Description Length (GMDL), to regularize geometric noises is introduced to enhance the repetition of identical line directionality, regular angle transition and to minimize the number of vertices used. After generating hypothetical regularized models, a global optimum of the geometric regularity is achieved by verifying the entire solution space. A comparative evaluation of the proposed geometric regulator is conducted using both simulated and real building vectors with various levels of noise. The results show that the GMDL outperforms the selected existing algorithms at the most of noise levels.