• 한국안전학회지
• /
• 제14권2호
• /
• pp.62-69
• /
• 1999

The quantitative risk assessment and consequence analysis by accident scenario in the process of EPS(Expendable Poly Stylene) reaction process are conducted. And the decision making process is studied followed by selecting various alternatives to safety management and facility improvement. The result are as follows; 1) The object of decision making through comprehensive risk assessment are the scenario which can cause four major accident, which are made by process analysis, work analysis and hazard identification. 2) Frequency analysis of ETA, FTA, HRA and consequence analysis of accident to each have been conducted. The each frequency values are yielded $9.2{\times}10_{-5}/yr$ to scenarios $1, 8.2{\times}10^{-4}/yr$ to scenario 2, $4.5{\times}10^{-6}/yr$ scenario 3 and $1.8{\times}10^{-7}/yr$ to scenario 4. The each scenarios have been conducted consequence analysis. 3) The calculated values have been obtained 4.00 to scenario 1, 3.25 to scenario 2, 2.43 to scenario 3 and 1.34 to scenario 4, as the weight value had been applied to the quantitative and normalized criteria of all components. As a risk criteria, scenario 1 have been selected, which is the most dangerous scenario as a result of ranking the scenario. 4) According to the importance of FTA and contribute to scenario 1, the cost-benefit values are yielded $8.05\times10^5[￦/yr]$ to final alternative(Al), $1.55{\times}10^5[￦/yr]$ to final alternative(A2) and $2.32{\times}10^5[￦/yr]$ to final alternative(A3). As a result of final alternative(Al) has been selected, which is the most optimized alternative.

• Asian Journal of Atmospheric Environment
• /
• 제6권3호
• /
• pp.206-221
• /
• 2012

Hazardous chemicals can be released from artificial turf used in some school playgrounds. To distinguish between Health risk assessment (HRA) exposure scenarios for this study, the ratio of elementary, middle and high schools was considered before final selection. Considering exposure pathways (inhalational, oral and dermal), media and materials were examined, targeting hazardous chemicals released from artificial turf playground-related products. Upon evaluation, the quantity of infill chips was shown to exceed the domestic product content standard (90 mg/kg) at eight (16%) out of 50 schools. PAHs were shown to exceed standards (10 mg/kg) at two (4%) out of the 50 schools. The excess cancer risk (ECR) of carcinogens was shown to be $1{\times}10^{-6}$ in most users for the worst exposure scenario. In children with pica, who represented the most extreme exposure group, the ECR was expected to be as high as $1{\times}10^{-4}$, showing the low risk level of carcinogens. The hazard index (HI) for individual chemicals was shown to be low, at around 0.1 or less, except for children with pica, according to the mean exposure scenario of artificial turf playground exposure. However, the HI was shown to exceed 1.0 in children with pica. Therefore, no direct health risk was found in using artificial turf playgrounds and urethane flooring tracks for the mean exposure scenario, except in children with pica.

• 한국항해항만학회지
• /
• 제43권6호
• /
• pp.395-402
• /
• 2019

최근 보다 안전하고 효율적인 해상운송시스템을 위한 해결책으로 자율운항선박의 개발 및 운용에 대한 논의가 활발히 진행되고 있다. 자율운항기술은 해양사고 방지, 선박의 연비 증진, 비용 절감 등 긍정적인 측면과 함께 선원의 일자리 감소, 업무의 변화, 보안문제 등 부정적인 측면도 상존하고 있다. 향후 자율운항선박의 시대가 도래 하더라도 육상 센터에서의 제어가 이루어지게 되므로, 육상 운항사의 상황인식과 같이 새로운 인적요인 이슈가 존재할 것으로 예측된다. 본 논문에서는 자율운항선박의 개발 및 운용과정에 고려해야 할 주요 인적요인 이슈를 고찰하고, 육상 센터의 제어에 따라 예상되는 육상 운항사의 의사결정 및 업무수행에 영향을 미치는 요소에 대한 식별과 영향 요소의 평가를 위한 인적 신뢰성 분석 방안을 제시하였다.

• 한국분말재료학회지
• /
• 제24권6호
• /
• pp.431-436
• /
• 2017

SiAlON-based ceramics are some of the most typical oxynitride ceramic materials, which can be used as cutting tools for heat-resistant super-alloys (HRSA). SiAlON can be fabricated by using gas-pressure reactive sintering from the raw materials, nitrides and oxides such as $Si_3N_4$, AlN, $Al_2O_3$, and $Yb_2O_3$. In this study, we fabricate $Yb_{m/3}Si_{12-(m+n)}Al_{m+n}O_nN_{16-n}$ (m=0.3, n=1.9, 2.3, 2.7) ceramics by using gas-pressure sintering at different sintering temperatures. Then, the densification behavior, phase formation, microstructure, and hardness of the sintered specimens are characterized. We obtain a fully densified specimen with ${\beta}$-SiAlON after gas-pressure sintering at $1820^{\circ}C$ for 90 min. under 10 atm $N_2$ pressure. These SiAlON ceramic materials exhibited hardness values of ~92.9 HRA. The potential of these SiAlON ceramics for cutting tool application is also discussed.

• International Journal of Naval Architecture and Ocean Engineering
• /
• 제11권2호
• /
• pp.782-795
• /
• 2019

Safety is always acritical focus of exploration of ocean resources, and it is well recognized that human factor is one of the major causes of accidents and breakdowns. Our research developed a dynamic human reliability assessment approach, Predicted Mean Vote-Cognitive Reliability and Error Analysis Method (PMV-CREAM), that is applicable to monitoring the cognitive reliability of oceanauts during deep-sea missions. Taking into account the difficult and variable operating environment of manned submersibles, this paper analyzed the cognitive actions of oceanauts during the various procedures required by deep-sea missions, and calculated the PMV index using human factors and dynamic environmental data. The Cognitive Failure Probabilities (CFP) were calculated using the extended CREAM approach. Finally, the CFP were corrected using the PMV index. This PMV-CREAM hybrid model can be utilized to avoid human error in deep-sea research, thereby preventing injury and loss of life during undersea work. This paper verified the method with "Jiaolong" manned submersible 7,000 m dive test. The"Jiaolong" oceanauts CR(Corrected CFP) is dynamic from 3.0615E-3 to 4.2948E-3, the CR caused by the environment is 1.2333E-3. The result shown the PMV-CREAM method could describe the dynamic human reliability of manned submersible caused by thermal environment.

• 한국가스학회지
• /
• 제11권2호통권35호
• /
• pp.60-64
• /
• 2007

한국에서는 석유화학 산업의 역사가 30년 이상이 되어 시설이 노후화되기 시작하여 잠재적인 사고의 위험 가능성이 높아지고 있다. 지금까지의 석유화학 산업에서의 전통적인 위험성 평가와 시스템의 제어는 기계적인 결함에만 중점을 두었기 때문에 인간의 행동을 제어하는 것은 간과하여 왔다. 자동화 기술과 제어기술의 발전도 필요하지만 인간의 의사 결정 요소가 석유화학산업에서 사고를 예방하는데 필수적이다. 거의 모든 심각한 사고는 인간 행동과 안전 장비의 기계적인 결함이 동시에 부적당할 때 발생한다. 진보적인 인간의 신뢰성 분석 소프트웨어는 실패 데이터를 수집하고, 한국의 화학 산업에서 인간의 오류 확률을 분석하기 위해 개발되었다. 이 논문에서는 Root cause Analysis를 통한 결과와 PIF(Performance Influencing Factor) 평가 결과를 보여준다.

• 보건행정학회지
• /
• 제31권3호
• /
• pp.255-260
• /
• 2021

Background: Korea National Health Checkup Programs are aimed at the prevention and early detection of cardiovascular disease in adults. To establish a countermeasure for this tendency, The current Korea National Health Checkup Programs have been providing Health Risk Appraisal (HRA) since 2009, thereby focusing on individual lifestyle correction. However, from 2018, the dyslipidemia screening exam cycle has been changed from 2 to 4 years. Methods: In this study, we try to investigate whether policy decisions are valid based on domestic reports that have influenced policy decisions. First, considering the epidemiology of the domestic cardiovascular disease, dyslipidemia, and metabolic syndrome, the change of the 4-year cycle is appropriate or not. Second, whether the research method that applies came to make policy decisions appropriate or not. Third, our study also investigates whether the direction of policy decision was suitable for the second comprehensive national examination plan. Results: The data that are used in the previous study were that of 10 years ago and there also was a problem in selecting the data, especially the use of one of the research methods to calculate the signal to noise ratio that was aimed at improving health had some problems. This is a research method that does not match with the aim itself. Conclusion: Changing the screening cycle for dyslipidemia does not match the recent trend of general screening to effectively prevent cardiovascular disease in improving individual lifestyles in the national health checkup plan. Studying the relationship with metabolic syndrome, which can be an intermediate stage of cardiovascular disease, could be a policy direction that is more suitable for the national health examination comprehensive plan.

• 대한인간공학회:학술대회논문집
• /
• 대한인간공학회 1997년도 춘계학술대회논문집
• /
• pp.56-60
• /
• 1997

The study of human erroneous actions has traditionally taken place along two different lines of approach. One has been concerned with finding and explaining the causes of erroneous actions, such as studies in the psychology of "error". The other has been concerned with the qualitative and quantitative prediction of possible erroneous actions, exemplified by the field of human reliability analysis (HRA). Another distinction is also that the former approach has been dominated by an academic point of view, hence emphasising theories, models, and experiments, while the latter has been of a more pragmatic nature, hence putting greater emphasis on data and methods. We have been developing a method to make predictions about error modes. The input to the method is a detailed task description of a set of scenarios for an experiment. This description is then analysed to characterise thd nature of the individual task steps, as well as the conditions under which they must be carried out. The task steps are expressed in terms of a predefined set of cognitive activity types. Following that each task step is examined in terms of a systematic classification of possible error modes and the likely error modes are identified. This effectively constitutes a qualitative analysis of the possibilities for erroneous action in a given task. In order to evaluate the accuracy of the predictions, the data from a large scale experiment were analysed. The experiment used the full-scale nuclear power plant simulator in the Halden Man-Machine Systems Laboratory (HAMMLAB) and used six crews of systematic performance observations by experts using a pre-defined task description, as well as audio and video recordings. The purpose of the analysis was to determine how well the predictions matiched the actually observed performance failures. The results indicated a very acceptable rate of accuracy. The emphasis in this experiment has been to develop a practical method for qualitative performance prediction, i.e., a method that did not require too many resources or specialised human factors knowledge. If such methods are to become practical tools, it is important that they are valid, reliable, and robust.

• 한국지반공학회논문집
• /
• 제39권6호
• /
• pp.5-12
• /
• 2023

산사태 위험 지역을 사전에 조사하여 설정하는 것은 다수의 피해를 줄이기 위해 필요하다. 해당 연구의 목적은 machine learning 기법 중 분류 알고리즘을 활용하여 대상 지반의 안전율 분류를 수행할 수 있는 방법론을 제시하는 것이다. 산사태 위험 지역은 high risk area(HRA) 모델을 적용하였으며, 8개의 지반공학 물성치를 통해 위험 지역을 판단하였다. 분류 알고리즘은 decision tree(DT), K-Nearest Neighbor(KNN), logistic regression(LR) 그리고 random forest(RF)의 4가지가 활용 되었으며, 안전율 1.2~2.0 범위에 8가지 지반공학 물성치의 분류 정확도를 계산하였다. 정확도는 안전율이 1.2~1.7 범위에서 신뢰성 높게 나타났지만, 그 외 범위인 1.8~2.0 사이에서는 상대적으로 낮은 정확도를 보였다. 이를 극복하기 위하여 synthetic minority over-sampling technique(SMOTE) 알고리즘을 적용하여 데이터 개수를 증폭하였으며, 증폭한 데이터를 통해 분류 알고리즘을 적용하면 안전율 1.8~2.0 범위에서 정확도가 평균적으로 약 250% 증가한 것으로 나타났다. 해당 연구 결과는 SMOTE 알고리즘이 데이터 개수를 향상시켜 분류 알고리즘의 정확도가 개선된 것을 보여주며, 타 분야에도 정확도 향상에 적용 가능하다고 판단된다.

• 보건행정학회지
• /
• 제23권2호
• /
• pp.152-161
• /
• 2013

Korea has a single National Health Insurance program and all citizens are covered under this program, accounting 97% of the population, approximately 50 million people. Claims submitted by Health care providers are reviewed by Health Insurance Review and Assessment (HIRA) for the reimbursement. HIRA database contains not only individual beneficiary's information, but also healthcare service information such as diagnosis, procedures, prescriptions and tests for them. HRA database has gained attention as importance source for research due to its rich healthcare information and the demand of HIRA database has increased. Due to its tremendous size, however, researchers have had problems in accessing the database to conduct research. To meet this demand, we conducted a study to develop the inpatient sample data from HIRA database for research. This study has two purposes: 1) to determine a needed sample size; 2) to test reliability and validity of the sample data. We determined an adequate sample size to ensure representativeness and generality with additional consideration for convenience of calculation. The minimum sample size was 729,904 for the generality, and 488,861 for representativeness. After considering the convenience of calculation, our final sample size was 13% of the population, which was about 7.7 million beneficiaries. Age (5 years interval) and gender were used as stratification variables for sampling. In order to examine whether this sample data appropriately reflect population, we tested the reliability and validity of the sample data. From the sample data, we computed average expenditure of total claims per inpatient for 2011, frequency of top 30 disease, estimation of the number of stroke patients from the sample data, and then compared them to those from the population. Results confirmed reliability and validity of the sample data.