• Journal of Korean Society of Disaster and Security
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• v.5 no.2
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• pp.1-10
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• 2012

Natural disasters are occurring frequently due to typhoon and flood. Especially, damage scales are increasing these days because of climate change. When natural disasters occur, civil engineering officers investigate them for the recovery. If public facilities are damaged, the disaster damage investigation must be finished within 7days. Currently, natural disaster damage investigation is done on two levels, field investigation and data input into NDMS. However, having those two overlapped most of the time, and we must do subsidiary works things to register field investigation data into system. Work efficiency is decreased due to repetition of additional work. So, many civil engineering officers indicated problems such as lack of manpower and time. In this study, We developed work process on natural disaster damage investigation that involves using smart phone to solve problems such as shortage of time and manpower.

• Structural Monitoring and Maintenance
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• v.7 no.2
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• pp.149-166
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• 2020

This paper presents the results of an experimental investigation on a vibration-based damage identification framework for a steel girder type and a truss bridge based on acceleration responses to operational loading. The method relies on sensor clustering-based time-series analysis of the operational acceleration response of the bridge to the passage of a moving vehicle. The results are presented in terms of Damage Features from each sensor, which are obtained by comparing the actual acceleration response from the sensors to the predicted response from the time-series model. The damage in the bridge is detected by observing the change in damage features of the bridge as structural changes occur in the bridge. The relative severity of the damage can also be quantitatively assessed by observing the magnitude of the changes in the damage features. The experimental results show the potential usefulness of the proposed method for future applications on condition assessment of real-life bridge infrastructures.

• Structural Monitoring and Maintenance
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• v.4 no.2
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• pp.133-151
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• 2017

The paper describes the results of an experimental and numerical investigation into the structural and damage response of sandwich composites to low-velocity impact. Sandwich panels consisting of laminated composite skins with three different layups bonded to a PVC foam core were subjected to impact at various energy levels corresponding to barely visible impact damage (BVID) in the impacted skins. Damage assessment analyses were performed on the impacted panels to characterise the extent and the nature of the major failure mechanisms occurring in the skins. The data collected during the experimental analyses were finally used to assess the predictive capabilities of an FE tool recently developed by the authors for detailed simulation of impact damage in composite sandwich panels. Good agreement was observed between experimental results and model predictions in terms of structural response to impact, global extent of damage and typical features of individual damage mechanisms.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.3
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• pp.346-354
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• 2023

Objectives: Chemical accidents cause extensive human and environmental damage. Therefore, it is important to prepare measures to prevent their recurrence and minimize future damage through accident investigation. To this end, it is necessary to identify the accident occurrence process and analyze the extent of damage. In this study, the development process and damage range of actual chemical leakage accidents were analyzed using CFD. Methods: For application to actual chemical leakage accidents using FLACS codes specialized for chemical dispersion simulation among CFD codes, release rate calculation and 3D geometry were created, and scenarios for simulation were derived. Results: The development process of the accident and the dispersion behavior of materials were analyzed considering the influencing factors at the time of the accident. In addition, to confirm the validity of the results, we compared the results of the actual damage impact investigation and the simulation analysis results. As a result, both showed similar damage impact ranges. Conclusions: The FLACS code allows the detailed analysis of the simulated dispersion process and concentration of substances similar to real ones. Therefore, it is judged that the analysis method using CFD simulation can be usefully applied as a chemical accident investigation technique.

• Journal of Industrial Convergence
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• v.21 no.2
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• pp.93-101
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• 2023

In this study, the physical and chemical fiber damage caused by knives, scissors, and chemicals was analyzed and used as technical data to determine the cause of the damage. Using 4 types of knives, 5 types of scissors and 4 types of chemicals(Sulfuric Acid, Hydrochloric Acid, Sodium Hydroxide, Potassium Hydroxide) physical and chemical to Cotton, Wool, Polyester, Rayon, T/C (Polyester 50%, Cotton 50%), T/W (Polyester 50%, Wool 50%) Damages were created and analyzed for damage caused by tools and chemicals. For penetrating damage caused by knives and scissors, 'V' type damage was generally seen when the blade part was penetrated, 'T', 'ㅁ', ''C' type damage was found, and in the case of scissors, 'Y' ' This type of damage was common. Fiber damage caused by chemicals showed various damage such as remanent trace, corrosion, degraded, contracting, and color changes. Physical damage of fibers showed differences in characteristics according to the shape characteristics of tools, and chemical damage showed differences in characteristics according to chemicals and types of fibers.

• Earthquakes and Structures
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• v.22 no.4
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• pp.387-399
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• 2022

To study the seismic damage of masonry structures and understand the characteristics of the multi-intensity region, according to the Dujiang weir urbanization of China Wenchuan earthquake, the deterioration of 3991 masonry structures was summarized and statistically analysed. First, the seismic damage of multistory masonry structures in this area was investigated. The primary seismic damage of components was as follows: Damage of walls, openings, joints of longitudinal and transverse walls, windows (lower) walls, and tie columns. Many masonry structures with seismic designs were basically intact. Second, according to the main factors of construction, seismic intensity code levels survey, and influence on the seismic capacity, a vulnerability matrix calculation model was proposed to establish a vulnerability prediction matrix, and a comparative analysis was made based on the empirical seismic damage investigation matrix. The vulnerability prediction matrix was established using the proposed vulnerability matrix calculation model. The fitting relationship between the vulnerability prediction matrix and the actual seismic damage investigation matrix was compared and analysed. The relationship curves of the mean damage index for macrointensity and ground motion parameters were drawn through calculation and analysis, respectively. The numerical analysis was performed based on actual ground motion observation records, and fitting models of PGA, PGV, and MSDI were proposed.

• Journal of Korean Institute of Fire Investigation
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• v.11 no.1
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• pp.37-40
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• 2008

This paper deals with damage patterns of cabinet panel for low voltage deteriorated by flame. In order to analyze damage patterns, we used Metallurgical Microscope, x-ray system, and Fourier Transform Infrared spectroscopy. Firstly, Metallurgical microscope was used for analysis of electrical causes, such as electric short and overload Secondly, X-ray system was used for analysis of internal characteristics of circuit breakers. Lastly, Fourier Transform Infrared spectroscopy was used for analysis of damage direction by flame.

• Journal of Conservation Science
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• v.38 no.4
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• pp.314-326
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• 2022

Investigation of conservation status, optical survey, infrared thermography, and ultrasonic examination were performed on Avalokitesvara Bodhisattva mural and Buddhist Monk Bodhidharma mural to determine the conservation status and physical properties. As a result of investigation of conservation status, the types of damage are largely divided into the wall and finishing layer damage, painting layer degradation, damage due to restoration materials, stains and contamination, and biological damage. As a result of the optical survey, drawing, stains, and repainted site were confirmed. Result of the infrared thermography, the delamination of the finishing layer was confirmed, and some locations and shapes of the wooden lath inside the wall were identified. The result of the 3D scanning, the deviation, and the separation of the wall was confirmed. As a result of ultrasonic examination, it was confirmed that the physical properties of the mural were identified and the ultrasonic speed was relatively low due to physical damage such as delamination and exfoliation of the finishing layer and cracking. Ultrasonic speed values were also high in some wall cracks or delamination, and it was confirmed by the infrared thermography results that the wooden lath inside the wall was located in those parts. It was possible to understand that the wooden lath inside the walls affects the ultrasonic speed during the ultrasonic examination. Therefore, management through periodic inspection of the relevant elements is necessary, and a countermeasure for damage that may occur in the future should be prepared along with intensive monitoring of the major damage identified in this diagnosis result.

• Journal of the Korean Society of Safety
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• v.31 no.2
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• pp.41-48
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• 2016

Recently, the frequency and intensity of localized heavy rain and typhoon due to the abnormal climate has increased, and especially the damage by an avalanche of earth and rocks similar to the landslide of Umyeon Mountain has become a social issue. However, the standardized damage investigation method doesn't yet exist, so the systematic analysis of the data has not been carried out. In this regard, this study developed assessment items to conduct standardized damage investigation of debris flow. To achieve this, preliminary assessment items were derived from analysis of literature review and the Delphi technique of 12 experts who are engaged in research facility, academia and industry was conducted. As a result, 29 assessment items which can be classified into 6 groups were determined. Surveying the relevant hand-on workers, details assessment items in each group were determined by exploratory factor analysis and reliability analysis.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.03a
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• pp.1366-1375
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• 2010

The damage by Debrisflow is occurring repeatedly recently by influences of abnormal climate changes. To reduce damage of Debris flow, primarily establishes the suitable measures and apply, in order to do that it is important for investigate the actual condition of Debrisflow. However, it is difficult to understand the current situation of Debrisflow phenomenon because the limit of technical development. For the reduce damage by future Debrisflow, have to collect data, analysis and preservation base on real status of Debrisflow disasters. This paper will refer to The Proposal of Debrisflow Investigation development have been applied overseas to the The Proposal of Debrisflow Investigation which already proposed it at these papers with bases. And this paper will suggest currently face objective The Proposal of Debrisflow Investigation to be able to do utilization to a Debrisflow occurrence situation and state and further study analysis(2).