• Korean Chemical Engineering Research
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• v.61 no.1
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• pp.68-73
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• 2023

Smoke masks have attracted great interests and have been supplied widely for the improvement of the safety during fire evacuation. However, there is not sufficient research on the practical utility, certification status and easy-donning about commercial smoke masks, therefore it is difficult to determine the actual usefulness of the smoke masks. In this study, we conducted a survey on users' perceptions and experiences about the smoke masks, and investigated the status of certification of 54 commercial smoke masks. We also performed donning tests and examined degrees of discomfort for 4 types of the smoke masks. Although 22% of 235 respondents had experienced the smoke masks before the test, and 23% of the respondents did not know the smoke masks, 93% of the respondents expected that the smoke masks could protect users from fire smokes and toxic gases. It was found that 41% of the commercial smoke masks did not certify according to domestic or overseas performance standards. Most certification standards have not effectively regulated maximum wearing time for the smoke masks. Only ASTM E 2952 and KFIS 024 had specific standards for the maximum wearing time of 30 s. As a result of donning tests for 4 types of smoke masks, the wearing time of the hood-type mask and self-contained smoke mask exceeded 30 s, therefore these types of smoke masks might increase the required safe evacuation time. On the other hand, it was also found that short education about the donning could reduce the wearing time by 19% and numbers of improper wearing by 89%.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.22 no.3
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• pp.191-201
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• 2010

The breakwaters are designed by considering the cost optimization because a human risk is seldom considered. Most breakwaters, however, were constructed without considering the cost optimization. In this study, the optimum return period, target failure probability and the partial safety factors were evaluated by applying the cost optimization to the rubble mound breakwaters in Korea. The applied method was developed by Hans F. Burcharth and John D. Sorensen in relation to the PIANC Working Group 47. The optimum return period was determined as 50 years in many cases and was found as 100 years in the case of high real interest rate. Target failure probability was suggested by using the probabilities of failure corresponding to the optimum return period and those of reliability analysis of existing structures. The final target failure probability is about 60% for the initial limit state of the national design standard and then the overall safety factor is calculated as 1.09. It is required that the nominal diameter and weight of armor are respectively 9% and 30% larger than those of the existing design method. Moreover, partial safety factors considering the cost optimization were compared with those calculated by Level 2 analysis and a fairly good agreement was found between the two methods especially the failure probability less than 40%.

• Fire Science and Engineering
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• v.32 no.4
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• pp.50-59
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• 2018

Recently, huge life losses occurred in the elderly long-term medical care fires due to lack of escape safety. As part of the measures to enhance the effectiveness of fire escape safety, while they prolong the available safe egress time (ASET) of non fire compartments, a measure to shorten fire-fighter's arrival time by fire alarm notifying device should be implemented in these facilities. The four categories from the aspects of fire prevention/protection engineering were provided with the necessary component technologies for carrying out these helper-guided evacuations. Fire prevention engineered technology was presented by two provisions; one for ensuring small compartment sections by installing the fire rated wall between bed rooms and another for ensuring the fire retardant or/and non-flammable performance of finishing materials. Also fire protection engineered technology was presented by two items; one for imposing cooling effects by sprinklers and another for providing automatic fire alarm notifying functions to fire stations. In order to improve the escape safety of these facilities in Korea, alternative revisions may presented by considering insufficient provisions in the architectural/fire law provisions by analyzing the provisions of Japanese and domestic laws in detail.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.481-487
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• 2020

This study examined the behavior change of river levees during an earthquake by numerical analysis. Unlike conventional research using artificial earthquake waves, earthquake analysis was performed using real earthquake waves. The behavior of a river levee before and after an earthquake was compared and analyzed quantitatively. Studies show that the river levee has a safety factor of approximately 28.5% due to an earthquake. On the other hand, the minimum standard safety factor is satisfied. Vertical effective stress has decreased by 81.8% due to excess pore-water pressure generated by the earthquake. In addition, liquefaction occurs in most of the foundation soil. An examination of the stress-displacement behavior due to the earthquake revealed a large amount of settlement in the backfill layer. Most of the foundation soil yielded. Therefore, the target river levee is quite vulnerable to earthquakes. Through the results of this study, the necessity of refreshing the seismic design standards for river levees is required. This study can be used as basic data for estimating the approximate damage level and vulnerable areas.

• Korean Security Journal
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• no.55
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• pp.9-29
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• 2018

Recently, it has been frequently reported there were rapid increase of vehicle ramming attacks in the Western countries, such as Europe, United States of America, Australia, and Canada. Vehicle ramming attacks happened in Western countries specifically targeted civilians and maliciously intented to attack as many victims as possible. and resulted in significant number of casualties and wounds. Experts in terrorism analyze the increase of terrors using vehicle is largely due to the change of terror strategy of Islamic extremest groups like ISIS which encouraging would-be terrorist to use vehicles as an effective killing weapons. Accordingly, The most of countries experienced vehicle terrorist attacks began to build physical barriers including ballards, fences, and obstacles on the main shopping streets, transportation facilities, and famous crowded places and buildings in order to prevent mass killing by terrorists' vehicle ramming attack. Contrary to such swift respond to be prepared attacks using vehicle as a weapon Western countries, there are still lack of interests in preparing this type of terrorist attacks among domestic policy makers and scholars. To fulfill the research gap, this study aimed to investigate important issues regarding physical barriers in South Korea. The contributions, implications of this study and suggestions for policy implications of this study findings were discussed in results and discuss.

• Journal of the Korean association of regional geographers
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• v.21 no.2
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• pp.379-393
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• 2015

The fire damage has been increased as the frequency of fire incidence decreases with increasing in death and economic loss. Local governments are dependent on the activities of fire-fighters with crude preparedness and prevention for fire incidence. Most of researches on fire safety have focused on descriptive statistics which show general trends in fire incidence and condition. Here we tried to make a mutual causal model for fire damage, to make three big hypotheses with laying three small hypotheses under each big hypothesis. Five years statistics from public domains in the form of hardcopy or softcopy were collected and fifteen independent variables were selected to explain the number of death, the number of fire incidence and the amount of economic loss from fire incidence. The significances of statistics are different among the regional characteristics. The hypotheses were partially rejected and the meanings of rejected factors will refresh the tentative prejudice. It is necessary to revise the principle that the number of population and size of area are regarded as the most important criteria to allocate resources for fire control and to have the criteria flexible with results of our research such as the number of the weak to fire disaster.

• Journal of the Korean Society of Marine Environment & Safety
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• v.28 no.4
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• pp.533-541
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• 2022

An analysis of marine accidents that occurred in the last five years, revealed that 77.0 % of all grounding accidents and 66.1% of all marine casualties involved small vessels, which was a very high level relatively. The Mokpo Regional Maritime Safety Tribunal (Mokpo-KMST) inquired on 72 cases of marine accidents in 2021, of which 10 cases were grounding accidents. Furthermore, eight cases of grounding accidents occurred in small fishing vessels. This study analyzed eight cases of grounding accidents on small fishing vessels that inquired in the jurisdictional area of Mokpo-KMST in 2021. I found out that this grounding occurred in clear weather with good visibility (2-4 miles) and good sea conditions with a wave height of less than 1 meter. Furthermore, I found that the main causes of grounding were drowsy navigation due to fatigue, neglect of vigilance, neglect of checking ship's position, overconfidence in GPS plotter, and lack of understanding of chart symbols and tidal differences. To reduce grounding accidents of small fishing vessels, I suggested the following measures. First, crew members who have completed the able seafarer training course on bridge watchkeeping should assist to the master. Second, alarm systems to prevent drowsiness should be installed in the bridge. Third, the regulation should be prepared for the performance standards and updating GPS plotter. Finally, the skipper of small vessels should be trained periodically to be familiar with chart symbols and basic terrestrial navigation.

• Journal of the Korea Institute of Construction Safety
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• v.6 no.1
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• pp.7-11
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• 2024

Pump car is an equipment that transports concrete products as needed to the place where they are poured. In order to pour a large amount of concrete in a short period of time, using a pump car is the most efficient in terms of economic efficiency and quality control. However, recently, many casualties have occurred due to boom damage during concrete pouring, so this study suggests that improvements are needed in the equipment manufacturing stage, inspection standards for old equipment, and equipment rental system. The reason is that, as a result of the finite element analysis of the pump car, the significant stress acting at the second stage of the boom and the maximum stress at the top of the boom were found to be 895.39 MPa, and M.S. Since it was evaluated the lowest at 0.04, the need for reinforcement was recognized. And it was confirmed that the 2nd stage boom was the most stressful and vulnerable part of the 1st to 5th stage booms. Therefore, it is necessary to increase the thickness and rigidity of members at the design and manufacturing stage, and to reinforce the steel plates of currently used equipment. In addition, it is urgent to establish a system that makes non-destructive testing mandatory for all general construction machinery and holds inspection agencies responsible for missing boom defects during non-destructive testing and regular inspections.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.316-316
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• 2023

2022년 8월 수도권 이상폭우로 인해 서울 도심지역의 지하시설, 도로, 주택 등에 침수가 발생하면서 인명 및 재산피해가 발생하였으며, 특히 동서로 가로지르는 정체전선으로 좁고 긴 비구름이 집중되면서 국지적으로 피해가 집중되었다. 서울시의 경우 도시화에 따른 불투수지역 증가 및 내수배제 불량에 따른 빗물 역류로 인한 피해가 지속적으로 발생하고 있으며, 최근에는 기후변화에 따른 방재성능목표 강우량을 초과하는 빈도의 이상폭우로 인해 하천범람과 내수배제 불량에 따른 복합적인 원인으로 침수피해 가중되고 있는 실정이다. 또한 서울시의 경우 전체 자연적, 사회적, 경제적, 환경적 요인 등의 지역적 편차가 매우 큰 도시로 지형적인 특성뿐만 아니라 취약시설(병원, 학교 등), 수방시설물(하천, 배수시설, 빗물펌프장 등) 및 방재시설(대피소, 구호소 등) 밀도 등에 따른 침수 취약성 및 위험성 등의 편차가 매우 크기 때문에 지역특성에 대한 피해사례가 다원화 되고 있는 실정이다. 본 연구에서는 30년 이상의 종관기상관측(ASOS)과 서울시 자치구별 20년 이상의 방재기상관측(AWS)자료를 기반으로 CMIP6 SSP(Shared Socioeconomic Pathways, 공통사회 경제경로)시나리오에 따른 극한기후 지수(강수강도, 호우일수, 지속기간, 1일 최대강수량, 95퍼센타일 강수일수 등)에 대한 재현성을 평가하고 공간자기상관분석 등 시공간적인 강우특성에 대한 변화를 전망하였다. 특히 여름철 강우의 경우 자치구별 편차가 크게 나타났고 이를 통해 대도시의 도심지역의 경우 세분화하여 지역의 정확한 강우특성을 파악하는 것이 필요하다는 것을 확인할 수 있었다. 본 연구의 결과는 도심지의 방재성능 초과강우 정의와 기준을 수립하고, 장기적인 수자원 및 도시계획 차원의 대책을 마련하는데 활용될 수 있을 것으로 판단된다. 기후위기에 따른 기록적인 호우(지역별 방재성능을 초과하는 강우)에 따른 재해는 구조적인 대책을 통해 모두 저감할 수 없는 한계가 있다. 하지만 인명피해를 최소화하는 것을 목표로 기후위기에 대한 적응단계로 인식하고 수리·수문학적, 사회경제학적 등 지역특성에 따른 방재성능목표 강우량에 대한 재검토와 더불어 법제도(풍수해보험, 저류조설치 의무화 등), 개인별 재해예방, 취약계층 안전망 확보, 반지하주택 침수안전대책, 재해지도 개선 등 구조적/비구조적인 대책을 통합 수립 및 보완하는 것이 필요한 시점이다.

• Journal of the Korea institute for structural maintenance and inspection
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• v.19 no.2
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• pp.92-98
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• 2015

Recently, buildings tend to be large size, complex shape and functional. As the size of buildings is becoming massive, the need for structural health monitoring (SHM) technique is increasing. Various SHM techniques have been studied for buildings which have different dynamic characteristics and influenced by various external loads. "Abnormal behavior point" is a moment when the structure starts vibrating abnormally and this can be detected by comparing between before and after abnormal behavior point. In other words, anomalous behavior is a sign of damage on structures and estimating the abnormal behavior point can be directly related to the safety of structure. Abnormal behavior causes damage on structures and this leads to enormous economic damage as well as damage for humans. This study proposes an estimating technique to find abnormal behavior point using Hilber-Huang Transform which is a time-frequency signal analysis technique and the proposed algorithm has been examined through laboratory tests with a bridge model using a shaking table.