• Journal of the Korea Institute of Military Science and Technology
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• v.11 no.4
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• pp.107-115
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• 2008

Accurate extraction of traversable region is a critical issue for autonomous navigation of unmanned ground vehicle(UGV). This paper introduces enhanced extraction of traversable region by combining scene clustering with 3D world modeling using CCD(Charge-Coupled Device)/IR(Infra Red) image. Scene clustering is developed with K-means algorithm based on CCD and IR image. 3D world modeling is developed by fusing CCD and IR stereo image. Enhanced extraction of traversable regions is obtained by combining feature of extraction with a clustering method and a geometric characteristic of terrain derived by 3D world modeling.

• Journal of information and communication convergence engineering
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• v.10 no.4
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• pp.411-419
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• 2012

This paper proposes a semi-automatic image-based approach for 3-dimensional (3D) modeling of buildings along streets. Image-based urban 3D modeling techniques are typically based on the use of aerial and ground-level images. The aerial image of the relevant area is extracted from publically available sources in Google Maps by stitching together different patches of the map. Panoramic images are common for ground-level recording because they have advantages for 3D modeling. A panoramic video recorder is used in the proposed approach for recording sequences of ground-level spherical panoramic images. The proposed approach has two advantages. First, detected camera trajectories are more accurate and stable (compared to methods using multi-view planar images only) due to the use of spherical panoramic images. Second, we extract the texture of a facade of a building from a single panoramic image. Thus, there is no need to deal with color blending problems that typically occur when using overlapping textures.

• International conference on construction engineering and project management
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• 2017.10a
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• pp.242-244
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• 2017

Excavation for construction is implemented in natural geographical terrain using a variety of construction equipment. Therefore, 3D excavation simulation requires integration of geographical and equipment modeling. This paper proposes a technique that integrates geographical and equipment modeling for 3D simulations of construction excavation. The geographical model uses a digital map to show ground surface changes during excavation and the equipment model shows equipment movement and placement. This combination produced a state of the art 3D simulation environment that can be used for machine guidance. An equipment operator can use the 3D excavation simulation to help construction equipment operators with decisions during excavation work and consequently improve productivity.

• ETRI Journal
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• v.26 no.3
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• pp.218-228
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• 2004

Using stereo images with ephemeris data from the Korea Multi-Purpose Satellite-1 electro-optical camera (KOMPSAT-1 EOC), we performed geometric modeling for three-dimensional (3-D) positioning and evaluated its accuracy. In the geometric modeling procedures, we used ephemeris data included in the image header file to calculate the orbital parameters, sensor attitudes, and satellite position. An inconsistency between the time information of the ephemeris data and that of the center of the image frame was found, which caused a significant offset in satellite position. This time inconsistency was successfully adjusted. We modeled the actual satellite positions of the left and right images using only two ground control points and then achieved 3-D positioning using the KOMPSAT-1 EOC stereo images. The results show that the positioning accuracy was about 12-17 m root mean square error (RMSE) when 6.6 m resolution EOC stereo images were used along with the ephemeris data and only two ground control points (GCPs). If more accurate ephemeris data are provided in the near future, then a more accurate 3-D positioning will also be realized using only the EOC stereo images with ephemeris data and without the need for any GCPs.

• Journal of the Korean GEO-environmental Society
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• v.22 no.12
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• pp.33-40
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• 2021

The deterioration of underground facilities, disturbance of the ground due to underground development activities, and changes in ground water can cause ground subsidence accidents in the urban areas. The investigation on the geotechnical and hydraulic factors affecting the ground subsidence accident is very significant to predict the ground subsidence risk in advance. In this study, an analysis DB was constructed through 3D ground modeling to utilize the currently operating geotechnical survey information DB and ground water behavior information for risk prediction. Additionally, using these results, the relationship between the actual ground subsidence occurrence history and ground conditions and ground water level changes was confirmed. Furthermore, the methodology used to visualize the risk of ground subsidence was presented by reconstructing the engineering characteristics of the soil presented according to the Unified Soil Classification System (USCS) in the existing geotechnical survey information into the internal erosion sensitivity of the soil, Based on the result, it was confirmed that the ground in the area where the ground subsidence occurred consists of more than 40% of sand (SM, SC, SP, SW) vulnerable to internal erosion. In addition, the effect of the occurrence frequency of ground subsidence due to the change in ground water level is also confirmed.

• Korean Journal of Construction Engineering and Management
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• v.22 no.4
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• pp.29-40
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• 2021

Recently, interest in Building Information Modeling (BIM) has increased globally, and 3D modeling is a start for the application of BIM at construction sites. However, while many studies have been conducted on the efficiency of 3D modeling focused on civil facilities, there is a lack of research on the earthwork BIM. In particular, since 3D slope often has complex shapes depending on the ground models, the efficiency method for 3D slope are needed. This study analyzed the interfaces and procedures of other software to find out what functions users need. Then the functions to enter intervals between 3D faces, select multiple ground models, and improve the interface are reflected on the developed system and is able to efficiently perform modeling with only five steps, and reduce the number of clicks and inputs. As a result of conducting the test to verify the efficiency, using the developed system made skilled users complete modeling at least 1.8 times faster and unskilled people at least 2.4 times faster than using other software. This is expected to perform 3D slope modeling more efficiently, as well as to contribute to the activation of future BIM adoption for housing construction projects.

• Journal of KIBIM
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• v.6 no.4
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• pp.27-34
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• 2016

A Building Information Model (BIM) is an attempt to simulate the process of building structures in a three-dimensional (3D) digital space. While the technology is usually applied to structured buildings, bridges, and underground facilities, it is rarely applied to an unstructured environment of earthwork operations. If a BIM is used for earthworks, the 3D simulation can be used for construction equipment guidance and earthwork management. This paper presents a real-time, 3D earthwork BIM that provides a 3D graphical simulation of excavators in conjunction with geographic modeling. Developing a real-time, 3D earthwork BIM requires handling a variety of factors, such as geographical information and vehicular movement. This paper mainly focuses on the management of these attributes and provides a database design for storing and retrieving data. In an example application, a prototype of the 3D earthwork BIM is presented to understand what it would provide when used during earthwork operations at a construction site.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.1143-1145
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• 2003

Some of satellites such as IKONOS don't provide the orbital elements so that we can’ utilize the physical sensor model. Therefore, Rational Function Model(RFM) which is one of mathematical models could be a feasible solution. In order to improve 3D geopositioning accuracy of IKONOS stereo imagery, Rational Polynomial Coefficients(RPCs) of the RFM need to be updated with Ground Control Points(GCPs). In this paper, a method to improve RPCs of RFM using GCPs and 3D cube is proposed. Firstly, the image coordinates of GCPs are observed. And then, using offset values and scale values of RPC provided, the image coordinates and ground coordinates of 3D cube are initially determined and updated RPCs are computed by the iterative least square method. The proposed method was implemented and analyzed in several cases: different numbers of 3D cube layers and GCPs. The experimental results showed that the proposed method improved the accuracy of RPCs in great amount.

• Geophysics and Geophysical Exploration
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• v.19 no.1
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• pp.20-28
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• 2016

Recently many sinkholes have appeared in urban areas of Korea, threatening public safety. To predict the occurrence of sinkholes, it is necessary to investigate the existence of cavity under urban roads. Ground-penetrating radar (GPR) has been recognized as an effective means for detecting underground cavity in urban areas. In order to improve the understanding of the governing physical processes associated with GPR wave propagation, and interpret underground cavity effectively, a theoretical approach using numerical modeling is required. We have developed an algorithm employing a three-dimensional (3D) staggered-grid finite-difference time-domain (FDTD) method. This approach allows us to model the full electromagnetic wavefield associated with GPR surveys. We examined the GPR response for a simple cavity model, and the modeling results showed that our 3D FDTD modeling algorithm is useful to assess the underground cavity under urban roads.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.6
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• pp.687-695
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• 2011

Many internet portals provide maps with spatial information services. Recently, various images including aerial, satellite, street view, and photo-realistic 3D city models are provided as well as maps. This study suggested a method for geometric correction of the panoramic aerial images in the internet portal and 3D building modeling using information which is available in the internet. The key of this study is to obtain all necessary data easily from internet without restrictions. Practically, the ground control coordinates could be available from geo-referenced internet maps, and stereo pairs of the aerial images and close-range photographs for photo-realistic object modeling are provided by the internet service. However, the ground control points are not suitable for accurate mapping. RMSE of the plotting was about 9 meters and reduced upto 4 meters after coordinate transformation. The proposed methods would be applicable to various applications of photo-realistic object modeling which do not require high accuracy.