• The Journal of Korean Institute for Practical Engineering Education
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• v.3 no.1
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• pp.143-148
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• 2011

In this study, the damage to the bridge structure such as the crack and water leakage was assessed due to the increase of the vehicle load and traffic on the roads. In order to make this into the database, as a part of the automation system development for the bridge maintenance, the students themselves designed and developed their own inspection robotic system based on the idea of robots currently being developed overseas. Its field testing was conducted and its applicability assessed. During the design and fabrication, its connection to the details of the unit course taken in the undergraduate level was focused. In terms of new product development, the field application was possible due to the support of the academic-industrial cooperation firms. Furthermore, through the survey of the students, the improvements in the practical skills of the students who participated in this development process was affirmed.

• Journal of Korean Tunnelling and Underground Space Association
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• v.13 no.3
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• pp.159-176
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• 2011

A 3D laser scanner is widely used in various fields such as games, movies, medicines, art, design, etc. Many studies for utilizing the 3D laser scanner in the fields of civil engineering have also been carried out, for example, for systematically managing tunnel and/or bridge construction. However, since a software which is directly applicable to Korean construction system does not exist, the amount of data obtained from existing the 3D laser scanner is too much to handle in a systematic way. Therefore, in this paper, a new data processing technique was established which can rapidly and effectively treat the 3D laser scanning data. Moreover, a software that can systematically manage the tunnel construction was developed. The developed software can assess the construction quality of tunnel excavation such as under-break, over-break, cracks, leakage and efflorescence, etc. A 3D laser scanner and the developed software was applied to an in-situ tunnelling site, and verified usefulness of the 3D laser scanner. The developed software may be useful for tunnel maintenance as well as for systematic management of tunnel construction.

• Journal of Conservation Science
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• v.29 no.2
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• pp.93-102
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• 2013

The wooden Ksitigarbha Triad Statues (Treasure No. 1749) of Shinhungsa temple in Sokcho are enshrined in the inside of the Myeonbujeon Hall. The Statues are highly damaged physical weathering which are crack and exfoliation. Also, the Statues were deteriorated by chemical and biological weathering. This study carried out nondestructive method as deterioration map, ultrasonic measurement, X-ray and endoscopy survey for deterioration evaluation and conservation plan. As a result, Ksitigarbha Statue coated by dust and various pollutants. And gold-gilt of Statue's surface has peeled off. Head part of Mudokguiwang Statue was discolored from water leak in Myeongbujeon Hall. Domyeongjonja Statue is highly damaged by insects. Result of endoscopy, there were bee hives in the inside of the Statue. Therefore, we suggest that these Statues have need to do conservation treatment on the basis of diagnostic results.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.5
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• pp.75-81
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• 2011

Recently prestressed concrete bridges are generally used instead of reinforced concrete. PSC is more durable than RC because it can reduce crack problems, reinforcement corrosion, leakage and carbonation etc. And also PSC is more effective because there is no crack in tension area, and the entire concrete section is considered in section analysis. And it can reduce section size because vertical component by prestressing force can reduce the shear force. However, using high strength concrete can increase the self weight of bridge because of it's higher density. So the hollowed PPC girder with light weight aggregate can be a alternative. In this study the hollowed PPC girder with light weight aggregate is designed and the performance of hollowed PPC girder is evaluated by experimental tests as well as numerical analysis. As a result, The hollowed PPC girder of light aggregate behaved fully elastically under service load of 110kN, and the plastic behavior was showed after elastic behavior through experimental test, and it can be also estimated by numerical analysis.

• Spatial Information Research
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• v.16 no.2
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• pp.263-278
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• 2008

Nowaday, local governments have planned to manage intelligent underground facilities through the u-City project. But, the intelligent underground facilities are in need of the progressive approach because of the required huge financial resources. Therefore, the objectives of this research are (1) to prioritize the monitoring items of sensing technology developments, (2) to study technological feasibilities, and (3) to discover the killer application which expands ripple effects on economy. To achieve these objectives, final monitoring items were derived from the business analysis of the water supply, the local government survey, the hearing expert opinions and so on. The priority order of final monitoring items were technology developments of (1) the flowmeter flux, (2) the water leakage/crack, (3) the pressure of water supply pipes, and (4) the flux of filtration plants. The research significance is obtained from the derivation and the evaluation of the priority order and the actual demand for the water supply facility management. And, the research results will contribute to the strategic planning for the underground facility intelligence.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.3
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• pp.56-64
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• 2019

Various defects that occur in the maintenance stage are connected to all kinds of wasted resources and economic losses as additional investments are made. Residents are harmed temporally, materially, and psychologically, and businesses suffer not only monetary losses but also reduced credit ratings. The aim of this study was to increase the efficiency of quality management and minimize defect disputes by estimating the importance of the defect type considering the defect frequency and severity in apartment buildings. For this, 7,548 defect items for 48 apartment buildings were examined. The analysis confirmed that defects are concentrated on RC, finishing and MEP work. In addition, defects with high importance are identified as broken, incorrect installation, missing tasks, and water problems. In addition, the exterior wall/roof, the Internal wall, ceiling, and floor, which are constructed in the field, are more important than the furniture and MEP equipment installed in the field.

• Journal of the Society of Disaster Information
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• v.17 no.3
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• pp.556-567
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• 2021

Purpose: In this study, various methods of deep learning-based automatic damage analysis technology were reviewed based on images taken through Unmanned Aerial Vehicle to more efficiently and reliably inspect the exterior inspection and inspection of railway bridges using Unmanned Aerial Vehicle. Method: A deep learning analysis model was created by defining damage items based on the acquired images and extracting deep learning data. In addition, the model that learned the damage images for cracks, concrete and paint scaling·spalling, leakage, and Reinforcement exposure among damage of railway bridges was applied and tested with the results of automatic damage analysis. Result: As a result of the analysis, a method with an average detection recall of 95% or more was confirmed. This analysis technology enables more objective and accurate damage detection compared to the existing visual inspection results. Conclusion: through the developed technology in this study, it is expected that it will be possible to analysis more accurate results, shorter time and reduce costs by using the automatic damage analysis technology using Unmanned Aerial Vehicle in railway maintenance.

• Journal of Korean Tunnelling and Underground Space Association
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• v.25 no.3
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• pp.245-259
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• 2023

The purpose of this paper is to examine the most recent tunnel scanning systems to obtain insights for the development of non-contact mobile inspection system. Tunnel scanning systems are mostly being developed by adapting two main technologies, namely laser scanning and image scanning systems. Laser scanning system has the advantage of accurately recreating the geometric characteristics of tunnel linings from point cloud. On the other hand, image scanning system employs computer vision to effortlessly identify damage, such as fine cracks and leaks on the tunnel lining surface. The analysis suggests that image scanning system is more suitable for detecting damage on tunnel linings. A camera-based tunnel scanning system under development should include components such as lighting, data storage, power supply, and image-capturing controller synchronized with vehicle speed.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.28 no.6A
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• pp.873-880
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• 2008

When checking the state of deterioration or damage structures, regular visual inspection has very important role. At this point, a visual inspection is performed mainly by sketch or photography with a camera of inspectors. If that happens, it takes a lot of effort and time to inspect appearance damages. The purpose of this study is to develop the automatic recognition system for a more efficient and effective inspection of appearance damages. In the process, the image processing technology and the data management & analysis system for damage recognition are mainly developed and applied. This automatic recognition system enables inspectors or clients to obtain correct data that can recognize a damage, such as, crack, water leakage, efflorescence, delamination (peeling), spalling, etc. In addition, this study takes aim at the effect of secure safety, functional maintenance and extension of design lifetime according to build up continuous and systematic data management system.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.20 no.11
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• pp.510-519
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• 2019

The aim of this study was to set a defect classification framework and evaluate the defect risks in apartment buildings For this, approximately 15,056 defect items for 133 apartment buildings were examined. As a result of the analysis, the major defect of the RC work was cracks, which were found mainly in public locations. Moreover, the RC work was found to exhibit a high defect risk of water problem and surface appearance, which are highly connected with cracks. Second, the finish work has a high defect risk because it is composed of various work types, and there are many kinds of materials and construction parts involved. Third, the major defects of the waterproof work were incorrect installation and missing tasks, which have high defect risks in the garage. This is because defects that require rework occur mainly in the underground garage. Based on these results, this study proposed countermeasures for defect risk management to be considered in the construction, handover, post-handover, and occupancy phases. These have been set in detail based on the three zones: low frequency high severity (LFHS), low frequency low severity (LFLS), and high frequency low severity (HFLS).