• Proceedings of the Korean Geotechical Society Conference
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• 1990.10a
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• pp.97-110
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• 1990

This paper presents a case history of a deep open cut excavation of Nakagawa section for Futuoka Subway construction which adopted observational mettled against boiling failure and completed with success by modifying construction based upon field monitoring. One of the difficult conditions for the excavation was sandy layer with high water pressure which was anticipated boiling failure. The boiling was generally considered as one of the difficult phenomena to work with the observational method because of its unpredictable catastrophic nature. Laboratory experiments showed the existence of the prefailure movements of the ground and the possibility of the application of the observational method against the boiling failure. Construction step was planned to be modified, if necessary, based upon field monitoring and was completed with success.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.186-187
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• 2020

Damage to temporary facilities and structural members caused by excessive loads in the field continue to occur. If the load can be monitored in advance, the risk can be prevented. In this study, a load cell sensor is installed under the system support, and load data is wirelessly transmitted through a Bluetooth AP(wireless). Risk prediction system is proposed through an construction alarm when an abnormal load occurs through real-time multi-point monitoring by sensor location.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.5
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• pp.1119-1128
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• 2024

This study developed an anomaly detection algorithm for underground hydrogen pipelines using Distributed Acoustic Sensing (DAS) and Distributed Temperature Sensing (DTS) technologies. The LSTM-AE-based algorithm was tested in a real-world testbed, showing high performance in detecting third-party construction activities and gas leaks. The model achieved 99.86% accuracy, 100% precision, 99.74% recall, and a 99.87% F1 score for DAS data, and 99.95% accuracy, 100% precision, 95.24% recall, and a 97.44% F1 score for DTS data. These results demonstrate the algorithm's effectiveness in real-time monitoring and its potential to enhance the safety of hydrogen pipeline infrastructure. Future research will focus on optimizing the algorithm for broader applications.

• International conference on construction engineering and project management
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• 2022.06a
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• pp.904-911
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• 2022

Occlusion is one of the most challenging problems for computer vision-based construction monitoring. Due to the intrinsic dynamics of construction scenes, vision-based technologies inevitably suffer from occlusions. Previous researchers have proposed the occlusion handling methods by leveraging the prior information from the sequential images. However, these methods cannot be employed for construction object detection in non-sequential images. As an alternative occlusion handling method, this study proposes a data augmentation-based framework that can enhance the detection performance under occlusions. The proposed approach is specially designed for rebar occlusions, the distinctive type of occlusions frequently happen during construction worker detection. In the proposed method, the artificial rebars are synthetically generated to emulate possible rebar occlusions in construction sites. In this regard, the proposed method enables the model to train a variety of occluded images, thereby improving the detection performance without requiring sequential information. The effectiveness of the proposed method is validated by showing that the proposed method outperforms the baseline model without augmentation. The outcomes demonstrate the great potential of the data augmentation techniques for occlusion handling that can be readily applied to typical object detectors without changing their model architecture.

• Structural Monitoring and Maintenance
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• v.10 no.3
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• pp.191-205
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• 2023

In this paper, through operational modal analysis and ambient vibration tests, the dynamic characteristics of a multi-span simply-supported reinforced concrete highway bridge deck was determined and the results were used to assess the quality of construction of the individual spans. Supporting finite element (FE) models were created and analyzed according to the design drawings. After carrying out the dynamic tests and extracting the modal properties of the deck, the quality of construction was relatively assessed by comparing the results obtained from all the tests from the individual spans and the FE results. A comparison of the test results among the different spans showed a maximum difference value of around 9.3 percent between the superstructure's natural frequencies. These minor differences besides the obtained values of modal damping ratios, in which the differences were not more than 5 percent, can be resulted from suitable performance, health, and acceptable construction quality of the bridge.

• Journal of the Korea Institute of Building Construction
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• v.9 no.4
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• pp.103-109
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• 2009

The construction industry has the highest death rate related to safety accidents of any industry. Furthermore, in contrast to other industries, where the death rate related to safety accidents has been steadily declining, both the death toll and the number of accidents in the construction industry have been on the rise. Construction accidents occur when various risks increase in an intertwined way to reach a tipping point; a moment when such factors cannot be tolerated any longer Conventional safety management methods have restrictions in terms of their ability to fully prevent all types of safety accidents. This research considers ways in which USN technology can be applied to safety management on a construction site, and derives a method of applying USN technology for safety management monitoring. The tasks related to safety management on construction sites, as well as the occurrence of accidents, are first analyzed. By analyzing the characteristics of construction accidents, the factors that must be a priority and the factors that can be a lower priority are derived. Finally, the configuration of a monitoring system for safety management on a construction site to which USN technology is applied is presented. It is expected that safety accidents can be prevented from occurring on construction sites by applying this cutting-edge USN technology.

• Journal of the Society of Disaster Information
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• v.20 no.1
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• pp.106-116
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• 2024

Purpose: This paper conducts IoT and CCTV-based safety monitoring to analyze accidents and potential risks occurring at construction sites, and detect and analyze risks such as falls and collisions or abnormalities and to establish a system for early warning using devices like a walkie-talkie and chatbot service. Method: A safety management service model is presented through smart construction technology case studies at the construction site and review a relevant literature analysis. Result: According to 'Construction Accident Statistics,' in 2021, there were 26,888 casualties in the construction industry, accounting for 26.3% of all reported accidents. Fatalities in construction-related accidents amounted to 417 individuals, representing 50.5% of all industrial accident-related deaths. This study suggests implementing AI chatbot services for construction site safety management utilizing IoT-based health monitoring technologies in smart construction practices. Construction sites where stakeholders such as workers participate were demonstrated by implementing an artificial intelligence chatbot system by selecting major risk areas within the workplace, such as scaffolding processes, openings, and access to hazardous machinery. Conclusion: The possibility of commercialization was confirmed by receiving more than 90 points in the satisfaction survey of participating workers regarding the empirical results of the artificial intelligence chatbot service at construction sites.

• Journal of the Korean Society of Safety
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• v.21 no.1 s.73
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• pp.41-47
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• 2006

This paper introduces stress monitoring system for buried gas pipeline in poor ground. During the six months of improvement construction of poor ground, maximum settlement of gas pipeline is about 40 cm. This value represents relative small compared to the initial settlement estimation of ground improvement construction plan, 90 cm. Also, this paper includes the result of finite element analysis of gas pipeline to confirm safety of pipelines in poor ground. The stress monitoring system for gas pipeline was developed to guarantee the safety of buried gas pipeline in poor ground. Eventually, the ground improvement workings are ended safely and it is proved that the pipeline has no safety problem.

• Proceedings of the Korean Geotechical Society Conference
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• 2003.06a
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• pp.93-101
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• 2003

Steel frame-type retaining walls(SFRW) are constructed by on site bolting of prefabricated steel frames and internal filling of materials such as rocks with the size of 150-300mm. Easy & fast construction, superior drainage performance and structural performance to rigorous site conditions are some of the merits of applying the SFRW to various construction sites. After the development of the structural details, a test construction of SFRW, with the height of 6m and 30m in length, was carried out at an apartment site. After completion, several months of monitoring was carried out on the structure to check displacement, tilting, settlement, soil pressures and drainage characteristics. The results of the structural behavior of SFRW along with its construction methods are presented in the paper.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.34 no.5
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• pp.1589-1597
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• 2014

For several decades, economic growth has achieved in the aspect of productivity and effectiveness not environmental friendly. As a result, global warming is a major agenda to solve. Therefore, global effort to sustainable development has been adopted like UNFCCC and Kyoto protocol that aimed to reduce greenhouse gas. However, the construction industry has only focused on applying techniques for using less energy sources not monitoring sustainable construction and development. Therefore, this study developed a tool for monitoring greenhouse gas emissions in construction industry. The proposed system evaluates and estimates BAU (Business as usual) for each phase of a construction project. For this purpose, analyzed the greenhouse gas emission factors coincide to life cycle of a construction project. The scope of monitoring is determined according to data availability and emission factor. Then, the system framework is developed and the calculation logic is proposed the system features provide comparison between the emission estimates for eco-friendly design and the actual emission of construction and operation phases. The system would be utilized as a tool for supporting to green construction realization and green construction performance evaluation.