• Journal of the Korean Society of Safety
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• v.26 no.1
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• pp.21-26
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• 2011

Extinction and ignition characteristics of $CH_4$-air counterflow diffusion flame were numerically investigated using a Flame-Controlling Method(FCM). A skeletal reaction mechanism, which adopts 17 species and 58 reactions, was used in the simulation. The extinction and ignition conditions of the $CH_4$-air diffusion flames were investigated with varying the global strain rate. Upper and middle branches of S-curve for the peak temperature in the inverse of the global strain rate space were obtained with the FCM. The structures of diffusion flames in the upper and middle branches of S-curve were compared. It was found that the global strain rate was not correlated with the local strain rate well in the low global strain rate region. It is expected that the FCM is very useful to obtaining the extinction and ignition condition of diffusion flame, such as fires.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 1999.11a
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• pp.274-277
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• 1999

Y2k will be able to enormous disaster. The many make an effort to find a solution to problem of Y2k. Problem of Y2k must solution to as follow. First, problem of Y2k solution organization must constructed. Second, in step with each stage\ulcornerthe first, developing and complete stage, stage of Y2k solution must be constructed. Third, solution of Y2k must construct to hierarchy. hierarchy structure constructed form six stage to first stage, first stage is investigation resources, second stage is estimation influence, third stage is planing conversion, fourth stage is working conversion, fifte spot, sixth stage is diffusion on the spot.

• Fire Science and Engineering
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• v.32 no.3
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• pp.1-7
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• 2018

This study the effect of pyrolysis products ABC dry chemical and of monoammonium phosphate on wood surface. When the pyrolysis product was removed from the wood surface, monoammonium phosphate was removed due to the high viscosity of the transparent pyrolysis product, but the ABC dry chemical was removed in a lump form. Thermal analysis showed that the pyrolysis characteristics of each sample were similar but the weight of pyrolysis residue was 55.9% for ABC dry chemical and 25.2% for monoammonium phosphate. The additives added to the ABC dry chemical also affect the weight of the pyrolysis residue and the fire protection effect of metaphosphoric acid.

• International Journal of Advanced Culture Technology
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• v.7 no.3
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• pp.97-102
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• 2019

This study suggests a solution of an incentive system from the viewpoint of the external effect on the renting of firefighting qualifications and on rental agencies. Currently, the Human Resources Development Service of Korea does not have a penalty for neglecting to perform a search into qualification lending and rental agencies. In the short term, the penal clause should be strengthened so that companies and qualification holders cannot borrow or lend their qualifications. In addition, the Human Resources Development Service of Korea will increase the number of personnel dedicated to investigating the loaning of qualifications. It is necessary for the government to establish a penalty for neglecting to investigate the lending of qualifications for the Human Resources Development Service of Korea. In the long term, the state needs to make only minimal regulations. Also, the state needs to make companies and qualification holders feel like they benefit more when they are not borrowing or lending qualifications. The anticipated effect of this study is that the government will intervene appropriately by applying firefighting qualifications according to market principles. It can also be used as a basis for the revision of related laws on the renting of national technical qualification certificates and the investigation of rental agencies.

• Journal of the Korean Society of Industry Convergence
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• v.22 no.2
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• pp.105-110
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• 2019

Most titanium alloy waste with cutting oil was discarded without recycling process so that it can be caused by metal and oil fires. However, there is no fire management system and studies on the titanium or titanium alloy waste in spite of high fire risk. The purpose of this experimental study is to identify the fire risk of the titanium alloy waste with cutting oil. We collected the 120g waste which was made in the biomedical titanium alloy cutting process. The waste was burned and conducted thermal image analysis with infrared camera. The experimental results which illustrated the process, characteristics, and trends of fire are presented. Firstly, the cutting oil was burned and partially the titanium alloy waste was burned. The maximum temperature of the fire was more than $650^{\circ}C$ in some specific spots. These results means when a lot of titanium alloy waste with cutting oil was ignited, this fire could connect the titanium fire. In other words, the fire has a flammable liquid fire and combustible metal fire at the same time. The experimental study could be used fire prevention, response, and investigation of the titanium alloy waste.

• Steel and Composite Structures
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• v.31 no.2
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• pp.173-185
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• 2019

This paper presents experimental and numerical investigations of aluminum tubular members subjected to combined bending and web crippling. A series of tests was performed on square hollow sections (SHS) fabricated by extrusion using 6061-T6 heat-treated aluminum alloy. Different specimen lengths were tested to obtain the interaction relationship between moment and concentrated load. The non-linear finite element models were developed and verified against the experimental results obtained in this study and test data from existing literature for aluminum tubular sections subjected to pure bending, pure web crippling, and combined bending and web crippling. Geometric and material non-linearities were included in the finite element models. The finite element models closely predicted the strengths and failure modes of the tested specimens. Hence, the models were used for an extensive parametric study of cross-section geometries, and the web slenderness values ranged from 6.0 to 86.2. The combined bending and web crippling test results and strengths predicted from the finite element analysis were compared with the design strengths obtained using the current American Specification, Australian/New Zealand Standard and European Code for aluminum structures. The findings suggest that the current specifications are either quite conservative or unconservative for aluminum square hollow sections subjected to combined bending and web crippling. Hence, a bending and web crippling interaction equation for aluminum square hollow section specimens is proposed in this paper.

• Journal of the Korean Society of Industry Convergence
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• v.23 no.6_2
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• pp.927-934
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• 2020

Magnesium powder has been widely used in various industries because it is light weight and extremely high mechanical strength including aeronautics and chemicals. However, magnesium, as a combustible metal, poses serious safety issues such as fires and explosions if it is not managed properly. Especially, magnesium's max adiabatic flame temperature is 3,340℃ and it is impossible to extinguish it by using water, CO2 and Halonagents. The aim of this study is to identify the combustion characteristics of magnesium powder. We carried out a combustion experiment, using 1 kg of magnesium (purity > 99 %, particle < 150 ㎛). The features of the magnesium burning process were scrutinized using infrared thermal image analysis. Also, a field-emission scanning electron microscope (FE-SEM) were used employed to analyze particulate composites and properties. It concludes the significant tendency of magnesium fire and light, combustion carbide's particle characteristics. This study contributes to make better prevention and response manners to magnesium fires, as well as fire investigation measures.

• Journal of the Korean Society of Safety
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• v.37 no.5
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• pp.22-32
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• 2022

The domestic smart factory is being built and spread rapidly, mainly by mid-sized companies and large enterprises according to the government's active introduction and support policy. But these factories only promote production system and efficiency, so harmfulness and risk factors are not considered. Therefore, to derive harmful risk factors in terms of industrial safety for 12,983 government-supported smart factory workplaces from 2014 to 2019, industrial accident status analysis compared workplaces with automation facilities and government-supported workplaces with automation facilities. Also, to reduce risks associated with domestic smart factory processes, twenty government-supported workplaces with automation facilities underwent analysis, evaluating risks through a status survey using the process evaluation table. In addition, the status survey considered region, size, industry, construction level, and accident rate; the difference in risk according to the structure of the process was confirmed. Based on the smart factory process evaluation results, statistical analysis confirmed that serial, parallel, and hybrid structures pose different risk levels and that the risks of mixed structures are greater. Finally, safety control system application was presented for risk assessment and reduction in the smart factory process, reflecting the results of disaster analysis and actual condition investigation.

• Computers and Concrete
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• v.31 no.1
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• pp.71-84
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• 2023

In this paper, the effects of the thickness of cubic samples on the tensile strength of concrete blocks were studied using experimental tests in the laboratory and numerical simulation by the particle flow code in three dimensions (PFC3D). Firstly, the physical concrete blocks with dimensions of 150 mm×190 mm (width×height) were prepared. Then, three specimens for each of seven different samples with various thicknesses were built in the laboratory. Simultaneously with the experimental tests, their numerical simulations were performed with PFC3D models. The widths, heights, and thicknesses of the numerical models were the same as those of the experimental samples. These samples were tested with a new tensile testing apparatus. The loading rate was kept at 1 kg/sec during the testing operation. Based on these analyses, it is concluded that when the thickness was less than 5 cm, the tensile strength decreased by increasing the sample thickness. On the other hand, the tensile strength was nearly constant when the sample thickness was raised to more than 5 cm (which can be regarded as a threshold limit for the specimens' thickness). The numerical outputs were similar to the experimental results, demonstrating the validity of the present analyses.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.175-175
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• 2023

Detection and monitoring of wildfires are essential for limiting their harmful effects on ecosystems, human lives, and property. In this research, we propose a novel method running in the Google Earth Engine platform for identifying and characterizing burnt regions using a hybrid of Sentinel-1 (C-band synthetic aperture radar) and Sentinel-2 (multispectral photography) images. The 2022 Uljin wildfire, the severest event in South Korean history, is the primary area of our investigation. Given its documented success in remote sensing and land cover categorization applications, we select the Random Forest (RF) method as our primary classifier. Next, we evaluate the performance of our model using multiple accuracy measures, including overall accuracy (OA), Kappa coefficient, and area under the curve (AUC). The proposed method shows the accuracy and resilience of wildfire identification compared to traditional methods that depend on survey data. These results have significant implications for the development of efficient and dependable wildfire monitoring systems and add to our knowledge of how machine learning and remote sensing-based approaches may be combined to improve environmental monitoring and management applications.