• Nuclear Engineering and Technology
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• 제55권8호
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• pp.3017-3029
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• 2023

In the late in-vessel phase of a nuclear reactor severe accident, the internal heat transfer and crust evolution during the debris bed melting process have important effects on the thermal load distribution along the vessel wall, and further affect the reactor pressure vessel (RPV) failure mode and the state of melt during leakage. This study coupled the phase change model and large eddy simulation to investigate the variations of the temperature, melt liquid fraction, crust and heat flux distributions during the debris bed melting process in the hypothetical severe accident of HPR1000. The results indicated that the heat flow towards the vessel wall and upper surface were similar at the beginning stage of debris melting, but the upward heat flow increased significantly as the development of the molten pool. The maximum heat flux towards the vessel wall reached 0.4 MW/m². The thickness of lower crust decreased as the debris melting. It was much thicker at the bottom region with the azimuthal angle below 20° and decreased rapidly at the azimuthal angle around 20-50°. The maximum and minimum thicknesses were 2 and 90 mm, respectively. By contrast, the distribution of upper crust was uniform and reached stable state much earlier than the lower crust, with the thickness of about 10 mm. Moreover, the sensitivity analysis of initial condition indicated that as the decrease of time interval from reactor scram to debris bed dried-out, the maximum debris temperature and melt fraction became larger, the lower crust thickness became thinner, but the upper crust had no significant change. The sensitivity analysis of in-vessel retention (IVR) strategies indicated that the passive and active external reactor vessel cooling (ERVC) had little effect on the internal heat transfer and crust evolution. In the case not considering the internal reactor vessel cooling (IRVC), the upper crust was not obvious.

• 재활간호학회지
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• 제7권2호
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• pp.188-196
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• 2004

Purpose: This study was conducted to identify relationships between depression, family support, and rehabilitation-motivation in patients with cerebrovascular accident. Method: The data were collected from 'S' hospital in Seoul from Feb. 1, 2004 to Apr. 30, 2004. The data were analyzed using a SPSS 10.0 program for descriptive statistics, Pearson correlation coefficients and stepwise multiple regression. Result: The results were as follows: The mean rehabilitation-motivation was 119.89, which was slightly high. The rehabilitation-motivation was influenced by religion, education level, occupation, economic status, treatment fee, duration of hospitalization, level of language ability and ADL. Rehabilitation-motivation has showed correlation with family support (r=.538, p=.000) and depression (r=-.417, p=.000). The variables related to rehabilitation-motivation were identified as family support, level of ADL, occupation, depression, and education level, using stepwise multiple regression. They were accounted for 57% of predictability of the rehabilitation-motivation, with the family support the highest at 29.3%. Conclusion: With increasing post stroke patients in Korea, we need to pay more attention to the rehabilitation of them. This study indicates that health professionals need to focus on the intervention especially in increasing family support and in decreasing depression of the patients with cerebrovascular accident.

• Safety and Health at Work
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• 제10권2호
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• pp.205-212
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• 2019

Background: Workforce health is one of the primary and most challenging issues, particularly in industrialized countries. This article aims at modeling the major factors affecting accidents in the workplace, including general health, work-family conflict, effort-reward imbalance, and internal and external locus of control. Methods: A cross-sectional study was conducted in Esfahan Steel Company in Iran. A total of 450 participants were divided into two groups-control and case-and the questionnaires were distributed among them. Data were collected through a 7-part questionnaire. Finally, the results were analyzed using SPSS 22.0 and Amos software. Results: All the studied variables had a significant relationship with the accident proneness. In the case group, general health with a coefficient of -0.37, worke-family conflict with 0.10, effort-reward imbalance with 0.10, internal locus of control with -0.07, and external locus of control with 0.40 had a direct effect on occupational stress. Occupational stress also had a positive direct effect on accident proneness with a coefficient of 0.47. In addition, fitness indices of control group showed general health (-0.35), worke-family conflict (0.36), effort-reward imbalance (0.13), internal locus of control (-0.15), and external locus of control (0.12) have a direct effect on occupational stress. Besides, occupational stress with a coefficient of 0.09 had a direct effect on accident proneness. Conclusion: It can be concluded that although previous studies and the present study showed the effect of stress on accident and accident proneness, some hidden and external factors such as work-family conflict, effort-reward imbalance, and external locus of control that affect stress should also be considered. It helps industries face less occupational stress and, consequently, less occurrence rates of accidents.

• 한국의학물리학회:학술대회논문집
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• 한국의학물리학회 2002년도 Proceedings
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• pp.11-12
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• 2002

Accidental overexposures by radiotherapy have gathered attention recently in Japan. The widely publicized accidents have occurred at the government official benefit society hospital and at the hospital affiliated to a medical school. The accident at the government official benefit society hospital occurred when one of two existing accelerators was renewed. A radiotherapy planning system was also introduced at that time. Then treatment planning for the old and the new linear accelerator was performed using the system. There were variations in wedge factors for the 30 degrees wedge filter between the old and the new linear accelerator. That is, the difference in the structure of the wedge filter (30 degrees) resulted in variations of the wedge factors between both accelerators. In order to keep strength, a lead board was backed to the lead wedge filter for the new linear accelerator, whereas the wedge filter for the old one was made of the iron. The X-ray attenuation of the iron wedge filter is smaller than that of the lead wedge filter. The basic beam data of the old linear accelerator, however, wasn't delivered properly between the user and the maker. Then, the accident took place because the same wedge factor was used for the old and the new linear accelerator. On the other hand, the accident which occurred at the university hospital was brought about by the input mistake in initialization of the computer system when a linear accelerator was introduced. The input mistake was found when the software of the system was updated. If the dose had been measured and confirmed adequately, the accidents could have been prevented in both cases.

• 대한안전경영과학회지
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• 제14권2호
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• pp.1-9
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• 2012

As contemporary building construction type is getting higher and deeper, construction equipment usage is getting more, and related fatal accidents are on an increasing trend. Because of this, a method was drawn which could grasp the present state of construction equipment management and manage safety of the equipment more easily for accident prevention by choosing 2 kinds of Construction equipment which cause safety accident frequently among the equipment mainly used in construction site. This study suggested a method about construction equipment safety management using "smart phone" base which could be used in safety management for construction equipment by whomever in construction site. After attachment of QR code included safety checklist, It became possible that site managers could check more efficiently by scanning with their smart phone when they inspect equipment. Moreover, by the construction interested who didn't know what and how they have to inspect could point out unsafe condition in the early stage of equipment entering or take unsafe one out of the site by using new smart phone safety checking system is installed, it became possible that critical accident caused by construction equipment was prevented in advance.

• 한국항해항만학회지
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• 제41권6호
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• pp.437-444
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• 2017

위험 유해물질(HNS) 유출사고를 대비하기 위하여 본 연구에서는 지역별 산업 집중도를 지수화하여 동향을 파악하기 위해 쓰이는 집중도지수를 활용하여 HNS 사고의 지역별 집중도를 확인하였다. 이는 HNS를 포함한 해양 유출사고 데이터를 바탕으로 HNS 사고 규모 집중도지수와 HNS 사고 빈도 집중도지수를 수치화하여 하나의 값인 HNS 사고 집중도지수를 제시하는 방식이다. 도출된 지역별 HNS 사고집중도 지수값를 바탕으로 울산을 HNS 대비 최우선 지역, 여수, 부산, 태안을 HNS 대비 우선지역, 군산, 목포, 완도, 인천, 통영, 평택, 포항을 HNS 대비 필요지역, 그 밖에 해양유출사고가 발생하지 않은 동해, 보령, 부안, 서귀포, 속초, 제주, 창원을 HNS 대비 지원지역으로 그룹화하여 대비측면의 우선순위를 설정하였다.

• 공업화학
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• 제33권4호
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• pp.408-418
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• 2022

Marine accidents involving the entanglement of marine litter have continued to increase, with over 300 to 400 cases per year according to the statistical agency. Entanglement of marine litter may also lead to large-scale marine accidents which cause capsizing and sinking, thereby further causing detrimental casualties and material damages, and thus exceptional attention and care are required. In this study, Incheon, Busan, and Geoje and Tongyeong were found to be the high-frequency locations for accidents, which were selected by considering the ArcGIS analysis about the marine accidents of entanglement of marine litter and the occurrence frequency by the standard. The characteristics of the multiple accident areas involving entanglement of marine litter were the coastal cities where fishing facilities or marine leisure related conditions were activated, with the port which handles much of the traffic of outbound and inbound vessels located nearby. Marine plastic pollution impacts not only the marine ecosystem and food chain, but also the hull and engine of ships, and may further pose threats to the safety of vessels and crews. It is necessary to find a common link between the relevant areas and to strive to remove the root causes of marine accidents by reducing marine litter.

• 대한인간공학회지
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• 제30권1호
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• pp.41-53
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• 2011

Objective: The purpose of this paper is to introduce new research trends of human error and accident modeling and to suggest future promising research directions in those areas. Background: Various methods and techniques have been developed to understand the nature of human errors, to classify them, to analyze their causes, to prevent their negative effects, and to use their concepts during design process. However, it has been reported that they are impractical and ineffective for modern complex systems, and new research approaches are needed to secure the safety of those systems. Method: Six different perspectives to study human error and system safety are explained, and then seven recent research trends are introduced in relation to the six perspectives. The implications of the new research trends and viable research directions based on them are discussed from a cognitive systems engineering point of view. Results: Traditional methods for analyzing human errors and identifying causes of accidents have critical limitations in complex systems, and recent research trends seem to provide some insights and clues for overcoming them. Conclusion: Recent research trends of human error and accident modeling emphasize different concepts and viewpoints, which include systems thinking, sociotechnical perspective, ecological modelling, system resilience, and safety culture. Application: The research topics explained in this paper will help researchers to establish future research programmes.

• Journal of Trauma and Injury
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• 제27권3호
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• pp.50-56
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• 2014

Purpose: Rollover motor vehicle crashes have a higher injury severity and fatality than other motor vehicle crash types. From a left-quarter turn rollover accident of 25-passenger bus, we intend to assess the injury of the occupant and the injury severities according to the occupants' position. Methods: We carried out the 3 steps investigation of occupants' interview, visiting the repair shop and using the police report. We analyzed injuries sustained by occupants, and compared injury severities considering column, row in occupant's position and passenger interaction Results: The rollover involved 14 passengers in the bus who were all old women except a man driver. The most common injury was in the upper extremity, with six occurrences being a left clavicle fracture. Major injuries including hemothorax and pneumothorax were diagnosed at left side of the occupant. In the comparison of injury severity among driver's column (left side), mid column and passengercolumn, ISS of passenger column was the highest ($9.9{\pm}7.4$, $8.8{\pm}5.5$, and $10.3{\pm}4.0$, respectively, p>0.05). The injury severity of multiple occupants by row was higher than that of single occupant (10.8 vs. 3, p<0.05). Conclusion: An occupant must fasten their seat belt to prevent an injury by passenger interaction in the left-quarter turn rollover accident of a bus.

• 지역사회간호학회지
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• 제15권1호
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• pp.84-94
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• 2004

Purpose: The purpose of this study was to examine the health care management status of preschoolers depending on the children's characteristics. Methods: The sample of this study were 212 mothers of preschoolers attending Child Care Centers in three cities, Seoul, Daejon, and Suwon, in Korea. A self administered questionnaire developed by investigators was used to collect data from September 15 to October 31, 2002. Data was analyzed with SPSS 11.5 Win program. Results: 5.7% of the children had not completed their vaccination programs. Children who were second or later birth order showed less complete vaccination rates than firstborn babies. Children who had working mothers showed less complete vaccination rates than those whose mothers did not work. Among the various vaccinations, the DPT and MMR booster vaccination rates were the lowest. Home safety scores were higher when mothers have younger children. higher monthly incomes and reside in apartment type houses. Forty one(41%) of the preschoolers experienced accidents, and the accident rate was higher in boys and children with easy temperament. The most frequently experienced accident was laceration. Twenty eight point eight percent(28.8%) of the children experienced hospitalization because of various diseases. Most of the mothers perceived their children healthy. However, children who were second or third born were perceived less as healthy. Children in families with less monthly income were perceived as less healthy. Conclusions: This study provided basic data about preschoolers' health care management status focusing on vaccinations and accident rates. More attention should be paid to preschoolers' health and safety. Related factors found in this study should be considered when providing anticipatory guidance for parents.