• The Transactions of The Korean Institute of Electrical Engineers
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• v.62 no.6
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• pp.876-880
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• 2013

The major causes of electrical fire are classified to short circuit fault, overload fault, electric leakage and electric contact failure. The principal factor of the fire is electric arc or spark accompanied with such electric faults. Earth Leakage Circuit Breaker (ELB) and Molded_case Circuit Breaker (MCCB), that is, Residual Current Protective Devices (RCDs) used on low voltage distribution lines cut off earth leakage and overload, but the RCD can not cut off electric arc or spark to be a major factor of electrical fire. As the RCDs which are applied in low voltage distribution panel are prescribed to rated breaking time about 30[ms] (KS C 4613), the RCDs can't perceive to the periodic electric arc or spark of more short wavelength level. To improve such problems, this paper studies on an arc fault circuit interrupter (AFCI) using the distorted voltage wave in electric arc faults. The proposed voltage sensing type AFCI is an electrical fire prevention apparatus of new conception that operates a circuit breaker with sensing the instantaneous voltage drop of line voltage at electrical faults occurrence. The proposed AFCI is composed of control circuit topology using some semiconductor switching devices. Some experimental tests of the proposed AFCI confirm practicality and the validity of the analytical results.

• Journal of Korean Society of Water and Wastewater
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• v.34 no.1
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• pp.23-33
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• 2020

With growing expectations for economic cooperation between the two Koreas, there is much interest in participating in the construction of infrastructure in North Korea. In particular, water and sewage infrastructure is the four major social infrastructures in addition to housing, transportation, electricity and telecommunications. North Korea is known to have severe water pollution and ecosystem destruction in major rivers, water pollution and soil pollution in mining areas are serious, and water and sewage infrastructures in cities other than Pyongyang are known to be weak. Preemptive investment in water supply and drainage in North Korea is the foundation for securing the quality of life of the North Korean and is the foundation of public health and industry. It is a leading investment to reduce the cost of unification and is a new growth engine for the water reloded industry. In this study, we proposed a plan to exchange and cooperate in water environment for building water infrastructure of North Korea by examining the data related to water quality, water resources, water disaster, related legal system and human resources exchange situations in North Korea.

• Journal of the Korea Safety Management & Science
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• v.24 no.3
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• pp.15-21
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• 2022

This study examined the certification effects of safety and health management system (SHMS) on the establishment level of SHMS and accident statistics in construction industry. This study obtained the establishment level of SHMS for 106 construction companies surveyed from our previous study. In addition, three major accident statistics (mortality rate, accidental mortality rate, and injury rate) for the companies were collected from the database in Korean Occupational Safety and Health Agency. The statistical analysis results revealed that the establishment level for SHMS certified companies was significantly higher than those for uncertified or certification preparing companies. Furthermore, SHMS certified companies showed significantly smaller accident statistics compared to uncertified or certification preparing companies. The results of this study support the positive effects of SHMS on reducing major industrial accidents in construction companies.

• The Korean Journal of Emergency Medical Services
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• v.27 no.2
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• pp.31-40
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• 2023

Purpose: The study aims to provide basic data for understanding the department of paramedicines' bachelor's degree courses to enable curriculum development and reorganization. Methods: The 2023 academic curricula for all eleven universities with active departments of paramedicine offering bachelor's degrees were investigated from April 25 to May 10, 2023. Results: The average courseload was 22.0 units. There were 7.73 major subjects, with 19.45 units on average. The culture subject was available in 7 colleges and was 2.55 units on the average 1.18 subject. Grouping the major subjects showed that 15.3% of subjects were related to advanced paramedicine (the most common course), followed by 11.8% related to research methodology and seminar, and 10.8% related to radiology and simulations. Related subjects in statistics, disaster, and forensic science were also offered. Conclusion: This study found that the curricula of the departments of paramedicine differed from that of the general bachelor's degree. Going forward, university leaders should organize the paramedicine curriculum considering the environmental changes in emergency medicine and the scalability of EMT-Paramedic jobs.

• Earthquakes and Structures
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• v.25 no.4
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• pp.283-296
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• 2023

This paper presents experimental and numerical studies of seismic performance on reinforced concrete (RC) wide beam (WB) joints. Two RC-WB joint specimens and one conventional RC joint specimen were fabricated using the reinforcing details of longitudinal reinforcing bars in a beam as a variable, and quasi-static cyclic loading tests were performed. The results were used to compare and analyze the load-drift ratio relationship, failure mode, and seismic performance of the specimens quantitatively. In addition, a finite element (FE) analysis of the RC-WB joint was conducted, and the rationality of the FE model was validated by comparing it with the test results. Based on the FE model, a parametric study was conducted, where the ratio of longitudinal reinforcing bars placed on the outer and inner parts of the joint (𝜌_ex/𝜌_in) was a key variable. The results showed that, in the RC-WB joint, an increase of 𝜌_ex/𝜌_in leads to more severe damage to concrete, which reduces the seismic performance of the RC-WB joints.

• Journal of the Korean Society of Radiology
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• v.14 no.5
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• pp.553-561
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• 2020

In this study aims to investigate the radiation protection effect of avocado peel extracts on the Sprague-Dawely rats. 52 male rats were randomly classified into 4 groups. NC Group was a normal control group, PA Group was a group injected avocado peel extracts, IR Group was irradiated group, and lastly PA+IR Group was set as an irradiated group after injected of avocado peel extracts. Avocado peel extract was administered orally at 200 mg/kg once a day for 14 days before irradiation, and the radiation dose was systemically irradiated with 6 MV X-ray of 7 Gy. On the 4 and 21 days after irradiation, the experimental animals were sacrificed to evaluate the change in blood cell composition, spleen index, and histopathological evaluation of the liver and small intestine. As a result, the PA+IR Group showed a significantly greater recovery of lymphocytes(p<0.01), red blood cells(p<0.01), and platelets(p<0.05) than the IR Group. It was also confirmed that the activation of Superoxide Dismutase(SOD) was further increased. Histopathologically, observed that nuclei aggregation and cytoplasmic expansion were slightly reduced in the PA+IR Group in the liver. and the damage was significantly reduce(p<0.01) in the change of villi length due to damage to the small intestine cells. Based on the above results, avocado peel extract can be expected to act as a radiation protection agent that can reduce damage to blood cells and major organs caused by irradiation.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.44 no.3
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• pp.407-416
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• 2024

Over the past 20 years, there has been a rapid increase in the number and size of subway stations and underground structures worldwide, and the importance of safety for subway users has also continuously grown. Subway stations, due to their structural characteristics, have limited visibility and escape routes in disaster situations, posing a high risk of human casualties and economic losses. Therefore, an analysis of disaster vulnerabilities is essential not only for existing subway systems but also for deep underground facilities like GTX. This paper presents a case study applying a betweenness centrality-based disaster vulnerability analysis framework to the case of Gwanggyo Central Station. The analysis of Gwanggyo Central Station's base model and various disaster scenarios revealed that the betweenness centrality distribution is symmetrical, following the symmetrical spatial structure of the station, with high centrality concentrated in the central areas of basement levels one and two. These areas exhibited values more than 220% above the average, indicating a high likelihood of bottleneck phenomena during evacuation in disaster situations. To mitigate this vulnerability, scenarios were proposed to distribute evacuation flows concentrated in the central areas, enhancing the usability of peripheral areas as evacuation routes by connecting staircases continuously. This modification, when considered, showed a decrease in centrality concentration, confirming that the proposed addition of evacuation paths could effectively contribute to dispersing the flow of evacuation in Gwanggyo Central Station. This case study demonstrates the effectiveness of the proposed framework for assessing evacuation vulnerability in enhancing subway station user safety and can be effectively applied in disaster response and management plans for major underground facilities.

• Journal of the Korean Society of Safety
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• v.22 no.4
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• pp.43-50
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• 2007

Lack of understanding of the process chemistry and thermodynamics are the major reasons that can is lead to thermal runaway reaction in the chemical reaction process. The evaluation of reaction factors and thermal behavior in neutralization process of pigment plant are described in this paper. The experiments were performed in the C 80 calorimeter, and Thermal Screening Unit($TS^{u}$). The aim of the study was to evaluate the results of thermal stability in terms of safety reliability to be practical applications. It suggested that we be proposed safe operating conditions and securities for accident prevention through this study.

• Proceedings of the Safety Management and Science Conference
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• 2010.11a
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• pp.113-129
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• 2010

Proper pre-safety training is one of core mandatory in order to reduce injuries at the construction fields. In this study, we investigate the employee's opinions of safety training, safety recognition, the actual conditions of safety through survey. As a result of study, incident factors are roughly divided into technical factor, managerial factor, and educational factor. We confirmed that the educational factor led by deficiency of safety awareness and knowledge was the major factor. It needs to be resettled or revised properly to match with the incident trends and the safety training curriculum should also be improved and drastically revised with special quality. The managerial workers' safety recognition is lower than the site ones regarding the correct understanding of the importance of the training.. It suggest that the education method and system in construction fields might have fundamental problems.

• Journal of the Korea Safety Management & Science
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• v.15 no.4
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• pp.49-53
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• 2013

If industrial safety statistics are analyzed, among the total of 2,114 dead people from industrial disasters in 2011, construction workers took 29.4% with 621. The construction industry makes a lot of efforts to reduce the death toll. However, since the measures are not from the analysis of root causes but from superficial countermeasure plans near general matters, it is in a situation that the actual effectiveness is marginal. Therefore, in this paper, improvement measures were intended to be prepared in order to reduce accidents, by inspecting safety control systems of target companies with high accident rates among major construction firms and extracting overall problems of them.