• Journal of Korean Tunnelling and Underground Space Association
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• v.3 no.4
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• pp.35-55
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• 2001

Recently, as tunnel structures are getting older and decrepit, many tunnel inspections are carried out for evaluating the tunnel state and safety. But, because there is no exact standard for tunnel state and safety, depending on subjective decision, the new standard to assess the tunnel state is required. The existing standard including mainly the assessment of the state of tunnel lining is not considered the characteristics of tunnel as underground structures. Also, the item of assessment and process of grading and classifying the state of tunnel is not objective and systemetic. In this study, new standard for assessment of tunnel state is presented for improving the problems in evaluating the tunnel state and safety. In the new standard, the new items of assessment including geotechnical condition were selected and graded, the process in classifying the tunnel state is quantitative for objective assessment for tunnel state. This new standard and method is practically used in effective safety inspection and diagnosis and tunnel maintenance.

• Proceedings of the Korean Society of Computer Information Conference
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• 2022.07a
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• pp.49-52
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• 2022

건물 외벽에 발생하는 균열은 시설물 구조 안전에 영향을 미치며 그 크기에 따라 위험도가 달라진다. 이에 따라 전문검사관의 현장 점검을 통해 발생 균열 두께를 정밀하게 측정할 필요가 있고 최근에는 이러한 현장 안전점검에 인공지능을 도입하려는 추세다. 그러나 기존의 균열 데이터셋은 주로 콘크리트에만 한정되어 다양한 외벽에 강인한 모델을 구축하기 어렵고 균열 두께를 측정하기 위해 정확한 마스크(Mask) 정보가 필요하나 이를 만족하는 데이터셋이 부재하다. 본 논문에서는 다양한 외벽에 강인한 균열 구획화 모델을 목적으로 2,744장의 이미지를 촬영하고 매직 완드 기법으로 라벨링을 진행해 데이터셋을 구축 후, 이를 바탕으로 딥러닝 기반 균열 구획화 모델을 개발했다. UNet-ResNet50을 최종모델로 선정 및 개발 결과, 테스트 데이터셋에 대해 81.22%의 class IoU 성능을 보였다. 본 연구의 기술을 바탕으로 균열 두께를 측정하여 건축물 안전점검에 활용될 수 있기를 기대한다.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2013.10a
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• pp.119-121
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• 2013

최근 대규모 선박 및 해양플랜트 사고 발생을 계기로 각국의 정부와 관련 업계에서는 안전사고 예방을 위한 규제를 강화하고 기업차원의 안전관리도 철저히 점검하고 있다. 선박사고의 경우에는 1989년 "엑슨발데스호" 사고를 계기로 국제해사기구(IMO) 주도하에 유조선의 "2중 선체 의무화"를 추진했으며, 2012년에는 전 세계적으로 공식 시행되고 있다. 해양플랜트 사고의 경우에는 1988년 북해(North Sea)에서 발생한 Piper Alpha 폭발사고를 계기로 인적요인에 대한 관심이 높아졌으며, 2010년 멕시코만에서 발생한 "딥워터호라이즌호" 사고 이후 시추작업에 대한 안전점검과 인적오류 예방 및 관리를 위한 훈련을 강화하고 있다(배영일, 2012). 일반적으로 해양플랜트 사고의 원인은 구조물 자체의 오류가 20%이하이며, 예기치 못한 작업자의 행동으로 발생된 사고가 80% 이상을 차지하고 있다. 즉, 대부분의 사고는 operation 또는 maintenance 동안 발생하는 것으로 나타나고 있다. 본 발표에서는 해양플랜트 산업에서의 사고와 관련된 최근 연구현황 및 향후 연구 방향을 소개하고자 한다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.16 no.4
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• pp.25-33
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• 2012

In electric power transmission tower structures on offshore, implementation of life management using the event data of regular safety inspections for structural and material damages is strongly recommended. In this study, six tower structures in Sihwa Lake around Yeoungheung island were target bodies for the safety inspections. safety inspections for deterioration about each of six towers were performed about three items for steel member, five items for concrete foundation, and four items for steel-pipe pile in seawater and seawater itself. Safety inspections for steel members included the visual observations of surface appearances, the measurements of member thicknesses, and the checks of painting states. Also safety inspections for concrete foundations comprised the estimation of crack features, the evaluation of non-destructive compression strengths, and the measurements of neutralization depths and chlorides contents. For steel-pipe piles in seawater the inspections comprised the surveys of corrosion states in accordance with potential levels tests and anode tests, the analyses of photos taken on surfaces of the piles as well as the evaluation of seawater quality. A set of deterioration inspections was performed at the same positions around october of each year for three consecutive years. As a result in this study, Newly developed deterioration indexes have been applied profitably to maintain structural safety for electric power transmission towers by utilizing these event data systematically.

• Fire Science and Engineering
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• v.27 no.1
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• pp.60-65
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• 2013

From an accident at 2:00 a.m. in November 2nd, 2012 that one fire-fighter died while suppressing the E land World Inc. Fire in Bupyeong-Gu, Incheon, we concluded the problem and the improvement method of using the wireless communication (the two-way radio) that the fire safety officer and the safety crew use when identifying the safety of the fire scene. And after the investigation, we could find that the communication between the fire safety officer and the safety crew was difficult in the scene of the fire by voice because of much noise, so they could rely solely on the wireless communication. Therefore, we investigated the wireless communication and its frequency now used in Incheon Fire Safety Devision. Also, we compared with those of the military and the police. As a result, by making use of the wireless communication and its frequency currently possessed in Incheon Fire Safety Division, we found that the fire safety officer and the safety crew rescuing people at the risk of their own life in the various fire scene can communicate effectively.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.4
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• pp.1-7
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• 2019

As a unify operational processes of the safety inspection for major national facilities, it is expected that the efficiency and professionalism of the project will be enhanced. Also it is being emphasized that the importance of visual inspection that initially find physical and functional defects in facilities. In this study, we developed an E-PAD-based condition evaluation system to check the safety of the facility to overcome the problems and limitations of the existing inspection method. This system consists of introduction, work list, visual inspection, defect table and so on. It is possible to download the inspection drawings at the site and input the damage information to the drawings and check the evaluation grade. In order to verify the E-PAD based condition evaluation system, the inspection data of 10 sample bridges were inputted into the system and the evaluation results were compared. As a result, it was confirmed that the safety grade calculated from the system and the existing safety grade are the same. The feasibility analysis of the AHP method also showed that the function increased by 10%, cost by 36%, and value by 30% compared to the existing method. Therefore, it is expected to contribute to systematic data and information analysis system for improvement of facility management.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.1
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• pp.74-79
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• 2020

Safety inspection of cable-supported bridge has increasingly attention as many cable-supported bridges are currently constructed/operated. Whilst cables as a main component in cable-supported bridge should be inspected regularly, traditional method (visual inspection) has limitation to check the condition of cables properly due to restricted factors. It is evidently necessary to develop cable-inspection robot to overcome this concern. In this respect, the main aim in this study is to manufacture the improved robot compared with the existing robot. The improved functions of the robot in this study were that the robot can be operated in large cable diameter (greater than 200 mm) and climbing ability of the robot increases. In addition, electro-magnetic sensor as a non-destructive method in the robot was added to detect damaged cables and performance of the sensor was evaluated in indoor and field experiments. Consequently, the robot was able to move on the cable with ~0.2m/s and to detect damaged cables using the sensor. It was also confirmed that performance of the robot in field test is similar to that in indoor test.

• Journal of the Korea institute for structural maintenance and inspection
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• v.24 no.5
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• pp.150-157
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• 2020

In this study, an algorithm was developed to validate the seismic acceleration measurement data of the seismic acceleration measurement system using measurement data from public buildings currently in operation. Through the results of the study, an algorithm was developed to detect errors and abnormalities in the measurement data itself and the process of generating real-time data (MMA/sec) and event measurement data (MiniSEED), which are the main data generated by the system, and the basic data for determining the direction of inspection through measurement data analysis. It is expected that this will be used as a guideline to determine whether or not the seismic acceleration measurement system, which was managed as receiving/not receiving, is inspected and abnormal types of conditions.

• Proceedings of the Korea Water Resources Association Conference
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• 2018.05a
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• pp.447-447
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• 2018

최근 이상기후의 영향으로 특정지역 중심의 국지성 집중호우 발생 빈도가 증가하고 있으며, 집중강우의 영향으로 하천의 범람 사고 또한 증가하고 있는 추세이다. 이와 관련하여, 본 연구에서는 수문시설의 안전성 확보를 위해, 기후변화 측면에서 현재 운영 중인 안전점검 및 정밀안전진단 세부지침의 개선 사항을 검토하고, 이에 대한 개선방안을 제시하고자 한다. 먼저 본 연구에서는 수문시설의 안전성평가 실시 현황, 현장적용 사례 및 평가기준 비교 검토를 통해 개선사항을 도출하고자 하였으며, 검토된 결과는 다음과 같다. 시설물의 안전성 평가는 선택적으로 수행할 수 있도록 규정하고 있어, 주기적 평가가 수반되지 않고 있으며, 최근 수위 변동에 대한 시설의 안전성 확보여부가 확인되고 있지 않은 실정이다. 또한 수문시설의 조작대 접근성 및 문비 구조검토 안전성 평가는 설계 당시의 홍수위를 기반으로 한 평가항목으로, 하천의 홍수위 상승에 취약적 요소가 내재되어 있으며, 수문시설의 기존 평가체계에서는 시설물의 기능적 특성에 따른 평가결과를 확인하기 어렵다는 한계점이 있다. 이에 본 연구에서는 기존의 조작대 접근성, 내하력 및 문비 구조검토 안전성 평가 항목 외에 추가적으로 홍수조절능력에 대한 안전성평가 항목의 신설의 필요성과 기준을 마련하고, 수문시설의 기능적 특성을 고려한 단계별 평가 체계를 구축하였다.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 2002.05a
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• pp.515-520
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• 2002

전기제품은 전기를 사용하는 상품의 성질상 인명과 관련되는 위험성이 큰 제조물이라 할 수 있다. 전기난로와 같은 가장 단순한 구조의 전기제품도 사용과 보수 점검 방법에 따라 누전이나 감전에 의해 사고가 발생할 위험성을 지니고 있으며, 급속한 기술혁신에 의해 탄생하는 신제품의 경우에는 소비자의 오용의 가능성도 그만큼 커진다. 또한 가정용 전기제품들은 일반 국민이 광범위하게 사용하므로 위험성은 더욱 더 높아질 수 있다.(중략)