• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.97-98
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• 2023

Recently, the use of digital technology in architectural technology is gradually increasing with the development of various industrial technologies. There are artificial intelligence and drones in the field of architecture, and among them, deep learning technology has been introduced to conduct research in areas such as precise inspection of buildings, and it is expressed in a highly reliable way. When a building is deteriorated, various defects such as cracks in the surface and subsidence of the structure may occur. Since these cracks can represent serious structural damage in the future, the detection of cracks was conducted using artificial intelligence that can detect and identify surface defects by detecting cracks and aging of buildings.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2023.11a
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• pp.261-262
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• 2023

Drone is a suitable equipment for capturing images of cracks at construction sites based on its efficient mobility and high-resolution image acquisition capabilities. In this study, drone was used to acquire indoor construction sites framework images and deep learning technology was applied to detect cracks and measure width, and size. Finally, the usability of the process was verified based on the indoor crack monitoring system.

• Proceedings of the Korea Information Processing Society Conference
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• 2012.11a
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• pp.519-522
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• 2012

본 논문은 진공흡착방식을 이용한 벽오르는 로봇에 탑재하기 위한 임베디드 시스템의 설계와 영상처리 알고리즘의 구현에 관한 연구이다. 벽로봇은 안정적인 부착과 이동성을 기반으로 벽면에서의 위험 요인 발견과 지능적인 처리를 위해 영상처리가 가능하고 원격의 스마트 단말기와 실시간 통신이 가능한 환경을 구축하였으며 이상 물질을 탐지하기 위해 색상성분을 정규화하고 특정객체를 탐지 후 영상을 전송하는 방법을 구현하였다. 이러한 기능은 무인로봇을 이용해 위험한 벽 환경에서의 균열이나 이상 원인을 지능적으로 탐색하는 분야에 응용 가능하다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.05a
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• pp.299-300
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• 2013

본 논문은 진공흡착방식을 이용한 벽오르는 로봇에 탑재하기 위한 임베디드 시스템의 설계와 영상처리 알고리즘의 구현에 관한 연구이다. 벽로봇은 안정적인 부착과 이동성을 기반으로 벽면에서의 위험 요인 발견과 지능적인 처리를 위해 영상처리가 가능하고 원격의 스마트 단말기와 실시간 통신이 가능한 환경을 구축하였으며 이상 물질을 탐지하기 위해 색상성분을 정규화하고 특정객체를 탐지 후 영상을 전송하는 방법을 구현하였다. 이러한 기능은 무인로봇을 이용해 위험한 벽 환경에서의 균열이나 이상 원인을 지능적으로 탐색하는 분야에 응용 가능하다.

• Proceedings of the Korea Information Processing Society Conference
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• 2013.11a
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• pp.1429-1430
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• 2013

본 논문은 진공흡착방식을 이용한 벽오르는 로봇에 탑재하기 위한 임베디드 시스템의 설계와 영상처리 알고리즘의 구현에 관한 연구이다. 벽면에서의 위험 요인 발견과 지능적인 처리를 위해 영상처리가 가능하고 원격의 스마트 단말기와 실시간 통신이 가능한 환경을 구축하였으며 이상 물질을 탐지하기 위해 색상성분을 정규화하고 특정객체를 탐지 후 영상을 전송하는 방법을 구현하였다. 이러한 기능은 무인로봇을 이용해 위험한 벽 환경에서의 균열이나 이상원인을 지능적으로 탐색하는 응용이 가능하다.

• The Journal of the Acoustical Society of Korea
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• v.25 no.6
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• pp.257-268
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• 2006

To determine the faults of ceramic cup it is proposed to use pseudo reverberation time concept estimated by impact test in room. Schroeder curves estimated from impact test for a cup with small crack and without one are utilized to estimate pseudo reverberation time. Pseudo reverberation times are compared and discussed according to a sort of impact hammers and impact points and also boundary conditions. As a result. proposed method is proved to be very useful to detect the existence of faults for candidate cups.

• Journal of the Korean Society for Nondestructive Testing
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• v.29 no.5
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• pp.479-484
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• 2009

Nondestructive evaluation(NDE) of ceramic matrix composites is essential for developing reliable ceramics for industrial applications. In the work, C-Scan image analysis has been used to characterize surface crack of SiC ceramics nondestructively. The possibility of detection of surface crack were carried out experimentally by two types of ultrasonic equipment of SDS-win and $\mu$-SDS, and three types of transducer of 25, 50 and 125 MHz. A surface micro-crack of ceramics was not detected by transducer of 25 MHz and 50 MHz. Though the focus method was detected dimly the crack by transducer of 125 MHz, the defocus method could detect the shape of diamond indenter. As a whole, the focus method and the defocus method came to the conclusion that micro crack have a good possibility for detection.

• Journal of the Korean Society for Nondestructive Testing
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• v.23 no.1
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• pp.38-44
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• 2003

Performance demonstration with real flawed specimens has been strongly required for nondestructive evaluation of safety class components in nuclear power plant. Mechanical or thermal fatigue crack and intergranular stress corrosion cracking could be occured in the in-service nuclear power plant and mechanical fatigue crack was selected to study in this paper. Specimen was designed to produce mechanical fatigue flaw under tensile stress. The number of cycles and the level of stress were controlled to obtain the desired flaw roughness. After the accurate physical measurement of the flaw size and location, fracture surface was seal-welded in place to ensure the designed location and site. The remaining weld groove was then filled by using gas-tungsten are welding(GTAW) and flux-cored arc welding(FCAW). Results of radio graphic and ultrasonic testing showed that fatigue cracks were consistent with the designed size and location in the final specimens.

• Composites Research
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• v.31 no.4
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• pp.145-150
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• 2018

Various structural health monitoring (SHM) systems have been suggested for aerospace industry in order to increase its life-cycle and economic efficiency. In the case of aircraft structure madden with metal, a major concern was hot spots, such as notches, bolts holes, and where corrosion or stress concentration occurs due to moisture or salinity. However, with the increasing use of composites in the aerospace industry, further advanced SHM systems have been being required to be applied to composite structures, which have much complex damage mechanism. In this paper, a method of acoustic emission localization for composite structures using Q-switched laser and multiple Amplifier-integrated PZTs have been proposed. The presented technique aims at localization of the AE with an error in distance of less than 10 mm. Acoustic emission simulation and the localization attempt were conducted in the composite structure to validate the suggested method. Localization results, which are coordinates of detected regions, grid plots and color intensity map have been presented together to show reliability of the method.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.6
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• pp.950-956
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• 2013

This paper describes a sensitivity-coefficient-based iterative method for detecting cracks in a structure. The sensitivity coefficients of a cracked structure are obtained by changing its eigenvectors. The proposed method is applied to a cracked cantilever. The crack is modeled as a rotational stiffness. The predicted cracks are in good agreement with those from a structural reanalysis of the cracked structure.