• Nuclear Engineering and Technology
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• 제55권11호
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• pp.4266-4273
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• 2023

In a severe reactor accident, a crust will form on the surface of the molten material during the core melting process. The crust will have a contact melting with the internal components of the reactor. In this paper, the contact melting process of the molten material on the austenitic stainless steel plate bundles is studied. The contact melting model of parabolic molten material on the plate bundles is proposed, and the rule and main effect factors of the contact melting are analyzed. The results show that the melting velocity is proportional to the slope of the paraboloid, the heat flux and the distance between two plates D. The influence of melt gravity and the plate width on melting velocity is negligible. The thickness of the molten liquid film is proportional to the heat flux and plate width, and it is inversely proportional to the gravity. With the increase of D, the liquid film thickness decreases at first and then increases gradually. The liquid film thickness has a minimum against D. When the width of the plate is small, the width of the plate is the main factor affecting the thickness of the liquid film. The parameters are coupled with each other. In a severe reactor accident, the wider internal components of reactor, which can increase the thickness of the melting liquid film and reduce the net input heat flux from the molten material to the components, are the effective measures to delay the melting process.

• 대한인간공학회지
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• 제35권3호
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• pp.135-142
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• 2016

Objective: Objective of this study is to provide characteristics of injury frequency and severity by driving condition in large truck-related traffic collisions. Background: Traffic accidents involving large trucks draw a lot of attention in accident prevention and management policies since they bring about severe human and financial damages. Method: In order to identify the major risk factors of accidents by driving condition, 255 recognized traffic accidents by large truck drivers were analyzed in terms of time of the day, road type, and shape of the road. Results: The driving conditions in the results are represented by the following form of combination, "Road Type (Non-expressway or Express) - Shape of Roads (Straight, Curved, Downhill, or Intersection) - Time of Accidents (Day or Night)". In the analysis of injury frequency, Non-expressway-Straight-Day condition was the most frequent one. Meanwhile, Expressway-Curved-Day, Non-expressway-Curved-Night and Non-expressway-Intersection-Night were evaluated as high level in view of injury severity. Also, Expressway-Straight-Night is the driving condition that is the highest in risk among the conditions that have to be managed as grade "High". Non-expressway-Straight-Night, Non-expressway-Downhill-Day, and Non-expressway-Curved-Day are also categorized as grade "High". Conclusion and Application: Safety managers in the fields require basic information on accident prevention that can be easily understood. The research findings will serve as a practical guideline for establishing preventive measures for traffic accidents.

• 자동차안전학회지
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• 제13권3호
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• pp.78-85
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• 2021

Recently a traffic accident of heavy duty vehicles under the mandatory installation of ADAS (Advanced Driver Assistance System) is often reported in the media. Heavy duty vehicle accidents are normally occurring a high number of passenger's injury. According to report of Insurance Institute for Highway Safety, FCW (Forward Collision Warning) and AEB (Automatic Emergency Braking) were associated with a statistically significant 12% reduction in the rate of police-reportable crashes per vehicle miles traveled, and a significant 41% reduction in the rear-end crash rate of large trucks. Also many countries around the world, including Korea, are studying the effects of ADAS installation on accident reduction. Traffic accident statistics of passenger vehicle for business purpose in TMACS (Traffic safety information Management Complex System in Korea) tends to remarkably reduce the number of deaths due to the accident (2017(211), 2018(170), 2019(139)), but the number of traffic accidents (2017(8,939), 2018(9,181), 2019(10,095)) increases. In this paper, it is introduced a traffic accident case that could lead to high injury traffic accidents by being equipped with AEB in a bus. AEB reduces accidents and damage in general but malfunction of AEB could occur severe accident. Therefore, proper education is required to use AEB system, simply instead of focusing on developing and installing AEB to prevent traffic accidents. Traffic accident of AEB equipped vehicle may arise a new dispute between a driver's fault and vehicle defect. It is highly recommended to regulate an advanced event data recorder system.

• 한국건설안전학회 논문집
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• 제5권1호
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• pp.17-24
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• 2023

본 연구 목적은 산업재해로 인한 사망자와 부상자가 너무 많다는 비판이 오랫동안 지속되어 온 부분과 근로자의 죽음은 한사람의 죽음뿐만 아니라 그와 연결된 많은 사람들과 사회 전체에 악영향을 미친다는 문제임은 분명히 인식하고 엄중한 '중대재해처벌법'의 필요성은 공감을 하고 있다. 그러나 현행 중대재해처벌법은 노사 양측에서 애매하다는 논란의 여지가 있어 환영받지 못하고 있는 점과 안전보건 확보 의무를 위반한 경영책임자는 처벌과 입법 내용이 추상적이며 처벌 수위가 지나치다는점을 제언한다. 그리고 경영책임자의 해석과 중대산업재해의 애매한 부분으로 대부분의 기업들이 법률해석과 자문을 받고자 대형 로펌을 기용하므로 로펌만 배불리는 양상을 만들고, 기업은 CEO를 보호하기 위해 투입하는 비용은 정작 안전사고 예방비용으로 들어가야 하므로 모호성을 갖고 있는 지금의 시행령은 개정되어야 할 필요성이 있다는 것을 제언한다.

• 한국인터넷방송통신학회논문지
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• 제23권6호
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• pp.163-170
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• 2023

중대재해 처벌 등에 관한 법률의 등장으로 사업주와 경영책임자 및 법인 등은 산업현장에서 안전사고를 예방하기 위해 안전관리자를 대폭 늘리고, ISO 취득 등 많은 투자와 노력을 하고 있다. 또한 SSMS(Smart Safety Management System)을 도입하여, 인원의 관리 및 안전보호구의 관리 또한 진행되고 있다. 작업자의 생명을 보호하는 안전보호구에서 안전모, 안전고리, 안전복에는 IoT 기반의 관리 시스템이 적용되고 있지만 안전화의 경우 현장 관리자와 개인에게 맡겨지고 있고 여전히 안전사고에 취약한 상황이다. 이에 따라 본 연구에서는 현장 출입 시 작업자의 안전화 또한 착용 여부를 사전에 파악할 수 있도록 Raspberry PI 기반의 Sensor 인식 장비를 구현해 착용 여부를 확인하고 안전화 미착용으로 발생될 수 있는 사고를 예방하는 것을 목표로 한다.

• 문화기술의 융합
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• 제9권5호
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• pp.605-611
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• 2023

건설 현장의 사고는 중증외상환자가 발생하기 쉬운 특성 탓에 사망으로 이어지는 비율이 매우 높다. 중증외상환자의 사망률을 줄이기 위해서는 빠른 대처가 필요하며, 빠른 사고 대처를 위해 인공지능 기술과 카메라를 이용하여 사고를 감지하는 시스템들이 개발되었다. 그러나 기존 사고 감지 시스템들은 단일 카메라만을 사용하여, 사각지대로 인해 건설 현장의 모든 사고를 감지하기에 한계가 있다. 따라서, 본 논문에서는 다수의 카메라를 사용하여 감지 사각지대를 최소화하는 시스템을 구현하였다. 구현된 시스템은 다수의 카메라의 영상에서 YOLO-pose 라이브러리로 특징점을 추출하고, 추출된 특징점을 장단기 메모리(Long Short Term Memory) 기반 순환신경망에 입력하여 사고를 감지하였다. 실험 결과, 우리는 제안하는 시스템이 복수의 카메라 사용으로 감지 사각지대를 최소화하면서도 높은 정확도를 가지는 것을 확인하였다.

• 수산해양기술연구
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• 제50권4호
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• pp.614-622
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• 2014

The aim of this study is to research attributes of fishermen's occupational accidents for investigating the measure of risk control on situational condition in the Korean offshore and coastal fishing vessel. Using data of fishermen's occupational accidents are from National federation of fisheries cooperatives for 2013. The results were as belows; Occupational accident occurrence rate was 29.5‰, slips & trips and struck by object and contact with gear were shown severe occurrence pattern. Occupational accident occurrence rate of offshore fisheries was 130.2‰, coastal was 16.9‰, specially the risk rates were severely high in several type of danish seine, stow net and offshore trap. Death rate by accidents was 10.6‰ and by fall into the water in occurrence pattern was 5.5‰.

• 한국건축시공학회지
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• 제8권3호
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• pp.127-133
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• 2008

Safety accident resulting from construction projects getting larger and complex day by day has occurred more often than ever. Particularly, the accident caused by construction equipment, among others, has been on the rise. To prevent such accidents, it's necessary to come up with the measures for reducing the accident. In this study, the cause of safety accidents was analyzed, reviewing the cases of safety accident maintained by Korea Occupational Safety & Health Agency, and the measures for reducing the accident was suggested with computerized safety checklist. The scope of study was limited to excavator, and the result is summarized as below. 1) Investigation was conducted to identify the cases of accident by excavator with the primary causes. 2) Reduction measures were suggested by category of cause of excavator-caused accident. 3) Checklist to prevent the safety accident, which was based on primary causes, was suggested. 4) The measures to stir up safety consciousness and monitor the safety were suggested, making use of computerized system. This study is expected to lay the foundation for further study in future as well as make a great commitment to reducing the safety accident.

• Nuclear Engineering and Technology
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• 제50권5호
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• pp.673-682
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• 2018

One of the most widely used methods to estimate core damage during a nuclear power plant accident is containment radiation measurement. The evolution of severe accidents is extremely complex, leading to uncertainty in the containment dose rate (CDR). Therefore, it is difficult to accurately determine core damage. This study proposes to conduct uncertainty analysis of CDR for core damage assessment. First, based on source term estimation, the Monte Carlo (MC) and point-kernel integration methods were used to estimate the probability density function of the CDR under different extents of core damage in accident scenarios with late containment failure. Second, the results were verified by comparing the results of both methods. The point-kernel integration method results were more dispersed than the MC results, and the MC method was used for both quantitative and qualitative analyses. Quantitative analysis indicated a linear relationship, rather than the expected proportional relationship, between the CDR and core damage fraction. The CDR distribution obeyed a logarithmic normal distribution in accidents with a small break in containment, but not in accidents with a large break in containment. A possible application of our analysis is a real-time core damage estimation program based on the CDR.

• 로봇학회논문지
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• 제16권3호
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• pp.199-206
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• 2021

The robot is an effective means to perform repetitive tasks quickly and accurately. It could be more effective in dangerous environments where human is difficult to access. The construction site is a dangerous environment with a high possibility of industrial accidents where heavy work is frequently carried out at a high place. In particular, an accident in the construction site is highly likely to lead to a severe disaster. Of course, various technologies are being developed to monitor the safety of workers in construction sites and prevent accidents, but there is a limit to eliminate the risk of accidents. Therefore, it is necessary to make efforts to replace workers exposed to dangerous environments with equipment or robots that could be controlled remotely in a more active way. In this study, Remote Precise Installation System was proposed to replace the workers exposed to the risk of accident at a high place during the bridge construction. Also, the conceptual design and analytical reviews of this system were carried out. Suppose Remote Precise Installation System is developed according to the derived concept and the target performance. In that case, this system is expected to be applied as a technology that can effectively replace the workers at the bridge construction site.