• Proceedings of the Korean Institute of Building Construction Conference
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• 2006.05a
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• pp.163-166
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• 2006

The purpose of the research is to assess the accuracy of steel bar detector among other nondestructive testing equipment. The result of previous research shows that the average errors of rebar detector are 14.7% for the cover depth, 2.3% for the rebar spacing, and 11% for the rebar diameter. But this experiment was performed at the laboratory and the mortar was used for covering the steel bars instead of concrete. In situ condition can be different from the laboratory's so the outcomes do not correspond with those of laboratory. This research was performed at the buildings to be reconstructed. Nondestructive and destructive testing can be performed side by side since the building if to be destroyed. Steel bar detector was operated on the beam and the column and concrete cover of those members was removed for the actual measurement of rebar depth, spacing, and diameter finally, presumed value can be directly compared with actual data.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.05a
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• pp.181-182
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• 2018

Decline in population and aging have led to the crisis of urban extinction, and the importance of urban regeneration has grown in the country. In addition to the meaning of redevelopment and reconstruction, the government will seek to secure sustainable living conditions, restore the economy, and restore social and cultural functions by utilizing the new technologies based on the efforts to restore the maximum cost to urban buildings and IT technologies.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2018.11a
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• pp.48-49
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• 2018

Recently the old buildings have been increasing and increasing reconstruction. As a result, the frequency of use of architectural adhesives has increased. Adhesives are not only used for bonding but also for building materials used in various fields. However, since the adhesive is made of an organic material, it causes various skin diseases and sick house syndrome, and when a fire occurs, harmful substances are generated, and incomplete combustion may cause personal injury. Therefore, in this study, to solve the disadvantages of conventional adhesives, we tried to develop inorganic adhesives using inorganic materials.

• Proceedings of the KSRS Conference
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• 2003.11a
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• pp.183-185
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• 2003

Spatially referenced mobile mapping (MM) images contain rich information of man-made objects , e.g. road centerlines, buildings, light poles, traffic signs ,billboards and line trees etc. Therefore, the applications in transportation, urban 3D reconstruction, utility management are implemented increasingly. It’s a fundamental issue lies in MM image process that how to orient this image in the object space including interior orientation of camera and the exterior orientation of image. In this paper, the algorithm of automatic acquirement of DC (Digital Camera) parameters based on MM images is illustrated. And then, the mapping between image space and object space for MM images is described.

• Proceedings of the Acoustical Society of Korea Conference
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• 1994.06a
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• pp.791-795
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• 1994

In this paper, the echo phenomena of Yingying Pagoda(ancient Chinese architecture), which may be resulted from interferences of reflection and diffraction by the pagoda eaves when pulse sound source is at some suitable positions, are investigated by an 1:2 scale model. There are valleys in frequency spectrum due to the interferences. On the other hand, taking eaves as wedges approximately, numerical spectral estimates are obtained from the closed-form impulse solution for diffraction of pulse point-source radiation by an infinite rigid wedge. The results of the numerical computations are similar to those of the model experiments. The study is a helpful guide to reconstruction or maintenance of this kind of ancient buildings.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.05a
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• pp.243-244
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• 2023

Noise, dust, etc. caused by road pavement cutting work, which frequently occurs in new construction or reconstruction of buildings, construction of complexes, etc., are environmental hazards and cause civil complaints. Recently, an eco-friendly pavement cutter is being developed to make the work low in noise and dust, however, the on-site cutting performance of the equipment has not been quantified. In this study, in order to derive a standard value for comparing the cutting performance of the eco-friendly cutter under development, a conventional pavement cutter was applied to four residential sites in Seoul and Gyeonggi-do, and the cutting data was collected. As a result of analyzing the collected data, the conventional pavement cutter showed a cutting performance of 12.3 to 20.2 sec/m, and the average was 27.2 sec/m. In the future, additional cutting experiments with various mixing ratios, materials, and depths are planned to confirm the performance of conventional pavement cutter in more detail.

• International Journal of High-Rise Buildings
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• v.13 no.2
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• pp.205-212
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• 2024

Unconventional with respect for tradition: The Karel Doorman building stands in the heart of Rotterdam's shopping area and is a remarkable combination of restoration and new development. On top of the Ter Meulen shopping centre - a monument of the post-war reconstruction period - we have built an extremely light-weight construction in steel and wood (See Figure 1 & 2). This unconventional building method - at least in the Netherlands - enabled the construction of a 70 metres high 'glass' residential building with 114 apartments and 156 parking places. In this way a remarkable historic Rotterdam building was preserved for the future while at the same time new housing was created on a sheer impossible location, contributing to the quality of life and social safety in this part of the city.

• Korean Journal of Remote Sensing
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• v.27 no.2
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• pp.121-130
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• 2011

This paper highlights the reconstruction of the rectilinear type of 3D rooftop model from satellite image data using centroid neural network. The main idea of the proposed 3D reconstruction method is based on the grouping of 3D line segments. 3D lines are extracted by 2D lines and DEM (Digital Elevation Map) data evaluated from a pair of stereo images. Our grouping process consists of two steps. We carry out the first grouping process to group fragmented or duplicated 3D lines into the principal 3D lines, which can be used to construct the rooftop model, and construct the groups of lines that are parallel each other in the second step. From the grouping result, 3D rooftop models are reconstructed by the final clustering process. High-resolution IKONOS images are utilized for the experiments. The experimental result's indicate that the reconstructed building models almost reflect the actual position and shape of buildings in a precise manner, and that the proposed approach can be efficiently applied to building reconstruction problem from high-resolution satellite images of an urban area.

• Spatial Information Research
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• v.16 no.1
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• pp.19-32
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• 2008

Usually in South Korea, land cover type and topographic undulation are frequently changed even in a narrow area. However, most of researches using aerial LIDAR(LIght Detection And Ranging) data in abroad had been acquired in the study areas to be changed infrequently. This research was performed to explore reconstruction methodologies of 3D surface models considering the distribution of land cover type and topographic undulation. Composed of variously undulatory forests, rocky river beds and man-made land cover such as streets, trees, buildings, parking lots and so on, an area was selected for the research. First of all, the area was divided into three zones based on land cover type and topographic undulation using its aerial ortho-photo. Then, aerial LIDAR data was clipped by each zone and different 3D modeling processes were applied to each clipped data before integration of each models and reconstruction of overall model. These kinds of processes might be effectively applied to landscape management, forest inventory and digital map composition. Besides, they would be useful to resolve less- or over-extracted problems caused by simple rectangle zoning when an usual data processing of aerial LIDAR.

• Nuclear Engineering and Technology
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• v.55 no.2
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• pp.681-689
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• 2023

Purpose: Muons are characterized by a strong penetrating ability and can travel through thousands of meters of rock, making them ideal to image large volumes and substances typically impenetrable to, for example, electrons and photons. The feasibility of 3D image reconstruction and material identification based on a cosmic ray muons tomography (MT) system with triangular bar plastic scintillator detectors has been verified in this paper. Our prototype shows potential application value and the authors wish to apply this prototype system to 3D imaging. In addition, an MT experiment with the same detector system is also in progress. Methods: A simulation based on GEANT4 was developed to study cosmic ray muons' physical processes and motion trails. The yield and transportation of optical photons scintillated in each triangular bar of the detector system were reproduced. An image reconstruction algorithm and correction method based on muon scattering, which differs from the conventional PoCA algorithm, has been developed based on simulation data and verified by experimental data. Results: According to the simulation result, the detector system's position resolution is below 1 ~ mm in simulation and 2 mm in the experiment. A relatively legible 3D image of lead bricks in size of 20 cm × 5 cm × 10 cm used our inversion algorithm can be presented below 1× 10⁴ effective events, which takes 16 h of acquisition time experimentally. Conclusion: The proposed method is a potential candidate to monitor the cosmic ray MT accurately. Monte Carlo simulations have been performed to discuss the application of the detector and the simulation results have indicated that the detector can be used in cosmic ray MT. The cosmic ray MT experiment is currently underway. Furthermore, the proposal also has the potential to scan the earth, buildings, and other structures of interest including for instance computerized imaging in an archaeological framework.