• 한국화재소방학회논문지
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• 제28권5호
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• pp.23-29
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• 2014

다중구획공간내의 분무화재에 대하여 화재해석모델의 타당성을 파악하기 위해 BRANZFIRE 존 모델과 FDS 필드모델의 해석결과를 실화재 실험결과와 비교하였다. 분무화재 형성에 사용된 연료는 톨루엔과 메탄올이며 개방된 ISO-9705 공간에서 화재실험을 수행하여 발열량을 측정하였다. 화재발생공간과 복도공간에서 FDS 모델의 예측온도는 실험결과와 잘 일치하였으며 존 모델의 경우도 해석모델의 단순함에도 불구하고 만족할 만한 결과를 제공했다. FDS 모델의 타당성을 평가한 결과, 화재해석의 평균온도는 최대 오차 25% 범위에서 실험결과와 일치하고 있으며 전체 위치에 대한 평균값은 ${\pm}10%$ 이내로 신뢰할 만한 결과를 제공했다. 본 연구는 타당성 평가를 바탕으로 화재해석모델의 적용범위를 확대하고 모델한계를 설정함과 동시에 신뢰성 높은 화재안전성 평가에 활용하기 위한 근거자료를 제공하고자 한다.

• 한국환경보건학회지
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• 제42권2호
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• pp.92-101
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• 2016

Objectives: Outdoor workers are exposed to thermally stressful work environments. In this study, heat stress indices for harbor workers in summer were calculated to evaluate thermal comfort based on a human heat balance model. These indices are Physiological Subjective Temperature (PST), Dehydration Risk (DhR), and Overheating Risk (OhR) according to respective stage of cargo work in a harbor. In addition, we constructed a forecast system to provide heat stress information. Methods: Thermophysiological indices in this study were calculated using the MENEX model (i.e. the human heat balance model), which used as inputs the meteorological parameters, clothing insulation, and metabolic rate for each stage of cargo work in the harbor of Masan over the course of seven days, including a four-day heat wave. The forecast heat stress information constructed for Masan harbor was based on meteorological data supported by the Dong-Nae Forecast from the KMA (Korea Metrological Administration) and other input parameters. Results: According to higher metabolic rate, thermophysiological indices showed a critical level. In particular, PST was evaluated as reaching the 'Very hot' or 'Hot' level during all seven days, despite the heat occurring over only four. It is important in a regard to consider the work environment conditions (i.e. labor intensity and clothing in harbor). On a webpage, the forecast thermophysiological indices show as infographics to be easily understand. This webpage is comprised of indices for both current conditions and the forecast, with brief guidance. Conclusion: Thermophysiological indices show the risk level to health during a heat wave period. Heat stress information could help to protect the health of harbor workers. Further, this study could extend the applicability of these indices to a variety of outdoor workers in consideration of work environments.

• 한국안전학회지
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• 제36권2호
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• pp.49-57
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• 2021

In the case of military supplies, any potential failure and causes of failures must be considered. This study is aimed at examining the failure modes of a rotorcraft landing system to identify the priority items. Failure mode and effects analysis (FMEA) is applied to the rotorcraft landing system. In general, the FMEA is used to evaluate the reliability in engineering fields. Three elements, specifically, the severity, occurrence, and detectability are used to evaluate the failure modes. The risk priority number (RPN) can be obtained by multiplying the scores or the risk levels pertaining to severity, occurrence, and detectability. In this study, different weights of the three elements are considered for the RPN assessment to implement the FMEA. Furthermore, the FMEA is implemented using a fuzzy rule base, similarity aggregation model (SAM), and grey theory model (GTM) to perform a comparative analysis. The same input data are used for all models to enable a fair comparison. The FMEA is applied to military supplies by considering methodological issues. In general, the fuzzy theory is based on a hypothesis regarding the likelihood of the conversion of the crisp value to the fuzzy input. Fuzzy FMEA is the basic method to obtain the fuzzy RPN. The three elements of the FMEA are used as five linguistic terms. The membership functions as triangular fuzzy sets are the simplest models defined by the three elements. In addition, a fuzzy set is described using a membership function mapping the elements to the intervals 0 and 1. The fuzzy rule base is designed to identify the failure modes according to the expert knowledge. The IF-THEN criterion of the fuzzy rule base is formulated to convert a fuzzy input into a fuzzy output. The total number of rules is 125 in the fuzzy rule base. The SAM expresses the judgment corresponding to the individual experiences of the experts performing FMEA as weights. Implementing the SAM is of significance when operating fuzzy sets regarding the expert opinion and can confirm the concurrence of expert opinion. The GTM can perform defuzzification to obtain a crisp value from a fuzzy membership function and determine the priorities by considering the degree of relation and the form of a matrix and weights for the severity, occurrence, and detectability. The proposed models prioritize the failure modes of the rotorcraft landing system. The conventional FMEA and fuzzy rule base can set the same priorities. SAM and GTM can set different priorities with objectivity through weight setting.

• 한국수자원학회논문집
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• 제56권2호
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• pp.151-163
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• 2023

본 연구에서는 수문학적 가뭄의 위험도 평가를 위해 이변량 지역빈도해석 방법을 적용하여 2022년 가뭄 빈도를 평가하였다. 현재 우리나라의 수문학 분야에서 사용 가능한 자료의 대부분이 자료연수가 부족하여 기존의 지점빈도해석 수행 시 도출되는 결과의 신뢰도에는 한계가 있다. 본 연구에서는 유입량 자료를 대상으로 지역빈도분석을 수행하였으며, 최종적으로는 가뭄사상의 결합재현기간을 도출하여 가뭄위험도 평가를 위한 각 댐 별 빈도분석을 수행하였다. 본 연구에서 제안되는 Copula 기반 지역빈도해석 모형은 가뭄변량 간의 상관성 및 극치 특성을 효과적으로 반영하는 것을 확인할 수 있었으며, 지역빈도해석모형과 지점빈도해석모형의 적합성 검정 결과의 비교를 통해 지역빈도해석 모형의 장점을 확인할 수 있었다. 결과적으로 2022년에 발생한 낙동강 유역의 수문학적 가뭄사상은 결합재현기간이 8년을 상회하는 것으로 나타났으며 남강댐의 경우 결합재현기간이 20년으로 평가되어 낙동강 유역에서 상대적으로 심한 가뭄이 발생한 것으로 판단된다.

• 한국안전학회지
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• 제27권5호
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• pp.148-157
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• 2012

Reliability-based design optimization (RBDO) problem is usually formulated as an optimization problem to minimize an objective function subjected to probabilistic constraint functions which may include deterministic design variables as well as random variables. The challenging task is that, because the probability models of the random variables are often assumed based on limited data, there exists a possibility of selecting inappropriate distribution models and/or model parameters for the random variables, which can often lead to disastrous consequences. In order to select the most appropriate distribution model from the limited observation data as well as model parameters, this study takes into account a set of possible candidate models for the random variables. The suitability of each model is then investigated by employing performance and risk functions. In this regard, this study enables structural design optimization and fitness assessment of the distribution models of the random variables at the same time. As the first paper of a two-part series, this paper describes a new design method considering probability model uncertainties. The robust performance of the proposed method is presented in Part 2. To demonstrate the effectiveness of the proposed method, an example of ten-bar truss structure is considered. The numerical results show that the proposed method can provide the optimal design variables while guaranteeing the most desirable distribution models for the random variables even in case the limited data are only available.

• 에너지공학
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• 제6권2호
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• pp.220-229
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• 1997

본 연구이전에 다양한 몇몇 연구를 통하여 울진원전 인근주민들에게서 '도우넛효과'의 발생가능성이 가장 크다는 판단을 기초로 본 연구이전에 수행된 몇몇 연구결과를 검토하여 울진원전 인근주민에게서 '도우넛효과'의 발생가능성이 있는 것으로 판단하였다. 이에 해당지역에 대한 직접면접과 분석을 통하여 '울진원전 인근지역'에서 도우넛효과를 활용한 시설입지의 가능성을 확인하였다. 향후 방사성 폐기물 처분장 입지선정에 있어서 '도우넛효과'를 활용한 사전연구의 유용함을 실증적으로 제시하였다.

• 한국식품위생안전성학회:학술대회논문집
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• 한국식품위생안전성학회 2001년도 The Asia-Pacific Conference on Reproductive Biology and Environmental Sciences
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• pp.165-169
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• 2001

• 한국철도학회:학술대회논문집
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• 한국철도학회 2010년도 춘계학술대회 논문집
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• pp.2048-2051
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• 2010

Almost all companies have paid much attention to the safety management ranging from maintenance to operation even at the stage of designing in order to prevent accidents, but fatal accidents continue to increase throughout the world. In particular, it is essential to systematically prevent such fatal accidents as fire, explosion or leakage of toxic gas at factories in order to not only protect the workers and neighbors but also prevent economic losses and environmental pollution. In addition, HRA may be used to detect the human errors which may cause accidents or trace back to any mistake on the part of workers. Usually, HRA technique is used in association with other risk assessment techniques. Moreover, it can serve to enumerate the human errors which may occur during operation or down-time or correct the existing system to reduce the mistakes. This work focuses on the coincidence of human error and mechanical failure for management of human error, and on some important performance shaping factors to propose a method for improving safety effectively of the process industries.

• 보험의학회지
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• 제32권2호
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• pp.33-38
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• 2013

Coronary artery diseases are very important agenda in the insurance medicine. Insurance medicine is defined as using medical knowledge for insurance administration such as underwriting, claims, and customer satisfaction. This review article contains review of coronary artery disease in terms of insurance medicine. Estimation of extra-risks for acute myocardial infarction are MR of 349% and EDR of 41‰. In medical underwriting, individual life applicants can be assessed by Framingham's CHD risk assessment model. In claims, medical claims review is a useful method of consulting for claims staffs. Several diagnostic criteria of acute myocardial infarction are introduced in time. The universal definition of myocardial infarction by ESC/ACCF/WHF was demonstrated the most valuable predictor of 10-year mortality. Contents for State-Of-The-Art of the coronary artery disease are current antithrombotics. There are many novel anti-thrombotic agents such as ticagrelol, dabigatran, rivaroxaban, and pegnivacogin.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.46-47
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• 2017

Korea rapidly arranged urbanization and overpopulation with high growth of economy and all kinds of decrepit facilities are scattered all over the downtown. If there is a strong wind in fire, fire is rapidly increased by various fire spread factors. And Korea cannot build prediction model of urban fire combustion phenomena because there is no studies that physically explains the suitable flame phenomena for its real state. In this study, based on the Japanese Urban fire simulation to target the traditional market area and suitability of fire risk assessment were reviewed.