• Journal of the Korean Recycled Construction Resources Institute
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• v.12 no.1
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• pp.63-71
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• 2024

Through the development of construction technology, various construction projects such as redevelopment projects, undergrounding of roads, expansion of subways, and metro railways are being carried out. However, this has led to an increase in the number of construction projects in existing urban centers and neighborhoods, resulting in an increase in the number of damages and disputes between neighboring buildings and residents, as well as an increase in safety accidents due to the aging of existing buildings. In this study, digital data was applied to a graphics program to objectify the progress of cracks by comparing the creation of cracks and the increase in length and width through photographic images and presenting the degree of cracks numerically. Through the application of the program, the error caused by the subjective judgment of crack change, which was mentioned as a shortcoming of the existing field survey, was solved. It is expected that the program can be used universally in the building diagnosis process by improving its reliability if supplemented and improved in the process of use. As a follow-up study, it is necessary to apply the extraction algorithm of the digital graphic data program to calculate the length and width of the crack by itself without human intervention in the preprocessing work and to check the overall change of the building.

• Smart Structures and Systems
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• v.1 no.4
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• pp.355-368
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• 2005

Large and complex structures are being built now-a-days and, they are required to be functional even under extreme loading and environmental conditions. In order to meet the safety and maintenance demands, there is a need to build sensors integrated structural system, which can sense and provide necessary information about the structural response to complex loading and environment. Sophisticated tools have been developed for the design and construction of civil engineering structures. However, very little has been accomplished in the area of monitoring and rehabilitation. The employment of appropriate sensor is therefore crucial, and efforts must be directed towards non-destructive testing techniques that remain functional throughout the life of the structure. Fiber optic sensors are emerging as a superior non-destructive tool for evaluating the health of civil engineering structures. Flexibility, small in size and corrosion resistance of optical fibers allow them to be directly embedded in concrete structures. The inherent advantages of fiber optic sensors over conventional sensors include high resolution, ability to work in difficult environment, immunity from electromagnetic interference, large band width of signal, low noise and high sensitivity. This paper brings out the potential and current status of technology of fiber optic sensors for civil engineering applications. The importance of employing fiber optic sensors for health monitoring of civil engineering structures has been highlighted. Details of laboratory studies carried out on fiber optic strain sensors to assess their suitability for civil engineering applications are also covered.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.6
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• pp.507-511
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• 2019

The purpose of an electric railway system contact wire is to supply electric energy to trains through a contacted pantograph. This energy is then converted into mechanical energy. Recent developments in overhead contact lines include the increase in the tension force up to 34 kN according to train speeds that reach up to 400 km/h with a verified safety. Rigid conductor catenary (R-Bar) for high speeds of up to 250 km/h have been developed in tunnels to save on construction costs. This is significant because minor defects in R-bars in aspects, such as height and stagger affect installation conditions. In this study, we propose the use of a detector that measures the static characteristics to reduce the R-bar installation errors. This detector has been developed to measure the height and stagger of the contact wire using video images.

• Smart Structures and Systems
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• v.23 no.3
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• pp.295-306
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• 2019

Shanghai Tower is a 632-meter super high-rise building located in an area with wind and active earthquake. A sophisticated structural health monitoring (SHM) system consisting of more than 400 sensors has been built to carry out a long-term monitoring for its operational safety. In this paper, a reduced-order model including 31 elements was generated from a full model of this super tall building. An iterative regularized matrix method was proposed to tune the system parameters, making the dynamic characteristic of the reduced-order model be consistent with those in the full model. The updating reduced-order model can be regarded as a benchmark model for further analysis. A long-term monitoring for structural dynamic characteristics of Shanghai Tower under different construction stages was also investigated. The identified results, including natural frequency and damping ratio, were discussed. Based on the data collected from the SHM system, the dynamic characteristics of the whole structure was investigated. Compared with the result of the finite element model, a good agreement can be observed. The result provides a valuable reference for examining the evolution of future dynamic characteristics of this super tall building.

• Journal of Drive and Control
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• v.20 no.1
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• pp.34-40
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• 2023

The agricultural tractor ROPS test method according to OECD code 4 is a test to assess whether the driver's safety area can be secured when a tractor overturns, and reliability should be ensured. In this study, a model formula and procedure for calculating measurement uncertainty expressing reliability in the field of agricultural machinery testing were established according to the ISO/IEC Guide 98-3:2008. The characteristics of the ROPS test device were assessed and repeated tests were performed, and the were used as factors to calculate the measurement uncertainty. As a result of repeated tests, the accuracy was higher than 1.9 % in all load directions; thus, they were, applied to calculate the type A standard uncertainty. The final expanded uncertainty was calculated within the range of less than ± 7.76 kN of force and ± 6.96 mm of deformation in all load directions.

• Smart Structures and Systems
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• v.31 no.5
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• pp.501-516
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• 2023

Dynamic irregularity and acceleration of bridges subjected to high-speed trains provide crucial information for comprehensive evaluation of the health state of under-track structures. This paper proposes a novel approach for real-time estimation of vertical track dynamic irregularity and bridge acceleration using deep generative adversarial network (GAN) and vibration data from in-service train. The vehicle-body and bogie acceleration responses are correlated with the two target variables by modeling train-bridge interaction (TBI) through least squares generative adversarial network (LSGAN). To realize supervised learning required in the present task, the conventional LSGAN is modified by implementing new loss function and linear activation function. The proposed approach can offer pointwise and accurate estimates of track dynamic irregularity and bridge acceleration, allowing frequent inspection of high-speed railway (HSR) bridges in an economical way. Thanks to its applicability in scenarios of high noise level and critical resonance condition, the proposed approach has a promising prospect in engineering applications.

• Proceedings of the Korea Information Processing Society Conference
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• 2021.11a
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• pp.152-155
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• 2021

최근 많은 이슈가 되고 있는 제 4 차 산업혁명 기술을 건설 분야에 적용하여 다양한 형태의 센서를 활용한 IoT 의 활용가치를 높이고 근로자의 위험사항을 사전에 예방함과 동시에 건설현장에서 IoT 기반 스마트 건설안전시스템 전호구축을 위한 아키텍처를 개발하는 것을 목적으로 하고 있다. 이를 위해 IoT 의 개념을 살펴보고, 현장 안전관리 프로세스를 근로자 편리성을 감안한 아키텍처로 전환연구를 하고자 한다. IoT 기반 스마트 건설안전시스템 구축을 위해서 활용 가능한 위험지역을 도식화하고, 적용 가능한 영역을 파악하였고, 다양한 사전예측분석 알고리즘을 활용하여 안전사고 예방에 관한 사전예측 유형을 분석하였다. 이를 바탕으로 위험지역에 대한 근로자의 동선을 파악한 후 위험지역에 사전정보 제공을 통한 건설현장의 IoT 기반 스마트 건설안전시스템을 전환해서 재해율 감소에 기여하고자 한다.

• Proceedings of the Korea Information Processing Society Conference
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• 2023.11a
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• pp.644-647
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• 2023

건설은 경제 발전과 일자리 창출에 중요한 역할을 담당하고 있다. 그러나, 건설 산업은 타 산업에 비하여 고위험 산업으로, 매년 많은 사고와 재해가 발생하고 있다. 노동부 중대산업재해감독과에 따르면 2022 년 재해조사 대상 사망사고 발생 현황 발표 결과, 건설 사고 사망자는 341 명으로, 전체 산업재해 사망사고자의 53%를 차지하고 있다. 최근 사회 변화와 다양한 경기 변동, 물가 상승에 따라 건설 공사 비용 절감을 위한 안정성 결여, 시공 품질 관리의 어려움, 근로자 안전 의식 부족 등의 문제가 심화되고 있다. 이에 따라, 건설 현장의 근본적인 안전문화의 정착과 함께, 첨단 ICT 기술을 활용한 지능형 건설 안전관리 시스템의 구축이 필요한다. 그리고, 건설안전관리를 위한 스마트 건설 안전관리통합관제시스템(SCMS)의 기능과 적용 범위를 더욱 확대함으로써 건설 현장의 안전사고 예방을 개선할 수 있을 것으로 기대된다. 이를 위해 지속적인 다양한 연구와 데이터 수집과 분석 등 기술적인 연구와 함께 법과 제도에 대한 개선 논의가 필요하다.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.39 no.4
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• pp.245-252
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• 2021

Underground facilities were constructed as needed by various management organizations, the result of which was the disordered and scattered underground spaces. This phenomenon can be viewed as the main cause of safety accidents in the underground space. To solve this problem, research on systematic construction and management of underground facilities should be conducted. Therefore, to improve the accuracy and the quality of information and to facilitate the systematic construction and management of underground facility information, this study aims to establish a 3D data model that conforms to international spatial information standards for pipeline underground facilities and to implement the data model to enable visualization. The result of this study can be used to improve the consistency of information not only between underground facilities, but also the correspondence between above ground and underground facilities. As such, this study has academic significance in that it presents an integrated data model that includes various objects in the ground and underground spaces and enables interoperability between diverse domain data.

• Journal of the Society of Disaster Information
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• v.16 no.2
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• pp.374-382
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• 2020

Purpose: Recently, structural defects in old safety management facilities have led to the collapse of buildings and facilities. The purpose of this study is to develop guidelines for the installation of regular monitoring systems that determine the optimal sensor location for monitoring exhibition space building sensors equipped with visual elements in order to analyze the risk signs of exhibition space buildings and develop measurement technology. Method: The components, installation locations, alarm criteria, and management measures of the instrument are presented. Result: A measure was proposed to determine the location of sensors, secure signal processing technology for analysis by having unified visual perception, and configure optimal 'risk sign detection' based on sensor monitoring through test-bed operation. Conclusion: The results of this study can be prepared against the disasters that may arise from the collapse of exhibition buildings, and contribute to strengthening safety management capabilities.