• 대한안전경영과학회지
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• 제4권3호
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• pp.35-43
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• 2002

For the unconfined vapor cloud explosion accident by the continuous release of gas-liquid flow of various saturated liquids in a vessel at ground level, overpressures were estimated and analyzed with various release conditions and materials by TNT equivalency model with vapor dispersion. We found that at same release conditions, overpressure showed n-heptane > xylene > n-hexane > toluene > n-heptane > benzene, respectively and that overpressure was increased with increasing the hole diameter and the storage pressure, but it was increased with decreasing the wind speed, the interested distance, and the vessel thickness.

• 대한교통학회:학술대회논문집
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• 대한교통학회 1997년도 제32회 학술발표회
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• pp.33-69
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• 1997

This study was conducted to develop a methodology to predict utility pole accident rates and to evaluate cost-effectiveness for safety improvement for utility pole accidents. The utility pole accident rate prediction model was based on the encroachment rate approach introduced in the Transportation Research Board Special Report 214. The utility pole accident rate on a section of highway depends on the roadside encroachment rate and the lateral extent of encroachment. The encroachment rate is influenced by the horizontal and vertical alignment of the highway as well as traffic volume and mean speed. The lateral extent of encroachment is affected by the horizontal and vertical alignment, the mean speed and the roadside slope. An analytical method to generate the probability distribution function for the lateral extent of encroachment was developed for six kinds of encroachment types by the horizontal alignment and encroachment direction. The encroachment rate was calibrated with the information on highway and roadside conditions and the utility pole accident records collected on the sections of 55mph speed limit of the State Trunk Highway 12 in Wisconsin. The encroachment rate on a tangent segment was calibrated as a function of traffic volume with the actual average utility pole accident rates by traffic volume strategies. The adjustment factors for horizontal and vertical alignment were then derived by comparing the actual average utility pole accident rates to the estimations from the model calibrated for tangent and level sections. A computerized benefit-cost analysis procedure was then developed as a means of evaluating alternative countermeasures. The program calculates the benefit-cost ratio and the percent of reduction of utility pole accidents resulting from the implementation of a safety improvement. This program can be used to develop safety improvement: alternatives for utility pole accidents when a predetermined performance level is specified.

• 대한교통학회지
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• 제33권1호
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• pp.100-111
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• 2015

주요국에서는 증가하는 노인운전자의 교통사고 경감을 위해 연령별 자동차 사고 위험도를 분석한 후, 위험도가 높은 고령자의 교통사고를 경감하기 위한 다양한 제도를 시행하고 있다. 최근 우리나라 교통사고는 감소하고 있지만 65세 노인운전자의 교통사고는 빠르게 증가하고 있음에도 불구하고 노인운전자의 자동차사고 위험도에 대한 실증연구가 부재하고, 관련제도 개선이 이루어지지 않고 있는 실정이다. 이에 본 연구에서는 우리나라 운전자들의 연령별 자동차사고 위험도를 분석하였는데, 25세 미만 연령층을 제외하고 65세 이상 노인운전자의 자동차사고 위험도가 가장 높은 것으로 분석되어졌다. 세계에서 가장 빠른 인구고령화를 경험하고 있는 우리나라에서도 주요국처럼 노인운전자에 대한 운전교육 및 운전면허 재발급 자격을 강화할 필요가 있겠다. 또한 노인운전자를 배려한 도로표지판 개선과 노인운전차량 스티커 부여, 그리고 자가운전 대신 대중교통을 운전하는 노인들에 대해 인센티브를 제공하는 유인체계의 변화가 필요하다.

• 대한교통학회:학술대회논문집
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• 대한교통학회 1997년도 제32회 학술발표회
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• pp.35-72
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• 1997

This study was conducted to develop a methodology to predict utility pole accident rates and to evaluate cost-effectiveness for safety improvement for utility pole accidents. The utility pole accident rate prediction model was based on the encroachment rate approach introduced in the Transportation Research Board special Report 214. The utility pole accident rate on a section of highway depends on the roadside encroachment rate and the lateral extent of encroachment. The encroachment rate is influenced by the horizontal and vertical alignment of the highway as well as traffic volume and mean speed. The lateral extent of encroachment is affected by the horizontal and vertical alignment, the mean speed and the roadside slope. An analytical method to generate the probability distribution function for the lateral extent of encroachment was developed for six kinds of encroachment types by the horizontal alignment and encroachment direction. The encroachment rate was calibrated with the information on highway and roadside conditions and the utility pole accident records collected on the sections of 55mph speed limit of the State Trunk Highway 12 in Wisconsin. The encroachment rate on tangent segment was calibrated as a function of traffic volume with the actual average utility pole accident rates by traffic volume strategies. The adjustment factors for horizontal and vertical alignment were when derived by comparing the actual average utility pole accident rates to the estimations from the model calibrated for tangent and level sections. A computerized benefit-cost analysis procedure was then developed as a means of evaluating alternative countermeasures. The program calculates the benefit-cost ratio and the percent of reduction of utility pole accidents resulting from the implementation of a safety improvement. This program can be used to develop safety improvement alternatives for utility pole accidents when a predetermined performance level is specified.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 춘계학술대회 논문집
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• pp.2472-2479
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• 2008

There exist several ways to analyse the accident causal analysis. Selection of a method and procedure depends on the characteristics of the system being analysed. Moreover, the selection should take into account of how the accidents causes are classified, since analysis model should make use of the classified causes to identify factors contributing to the risk of accidents. For railway case, a relational analysis as well as statistical estimation of significant hazard frequencies is applied to identify the dominant causes of accidents. This paper introduces outline of the causal analysis system, which is a significant part of the railway accident information and analysis system.

• Nuclear Engineering and Technology
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• 제37권3호
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• pp.245-258
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• 2005

This paper addresses two types of uncertainty: stochastic uncertainty and subjective uncertainty in probabilistic accident consequence assessments. The off-site consequence assessment code OSCAAR has been applied to uncertainty and sensitivity analyses on the individual risks of early fatality and latent cancer fatality in the population outside the plant boundary due to a severe accident. A new stratified meteorological sampling scheme was successfully implemented into the trajectory model for atmospheric dispersion and the statistical variability of the probability distributions of the consequence was examined. A total of 65 uncertain input parameters was considered and 128 runs of OSCAAR with 144 meteorological sequences were performed in the parameter uncertainty analysis. The study provided the range of uncertainty for the expected values of individual risks of early and latent cancer fatality close to the site. In the sensitivity analyses, the correlation/regression measures were useful for identifying those input parameters whose uncertainty makes an important contribution to the overall uncertainty for the consequence. This could provide valuable insights into areas for further research aiming at reducing the uncertainties.

• 한국도로학회논문집
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• 제14권6호
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• pp.121-129
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• 2012

PURPOSES : Traffic accidents at intersections have been increased annually so that it is required to examine the causations to reduce the accidents. However, the current existing accident models were developed mainly with non-linear regression models such as Poisson methods. These non-linear regression methods lack to reveal complicated causations for traffic accidents, though they are right choices to study randomness and non-linearity of accidents. Therefore, to reveal the complicated causations of traffic accidents, this study used structural equation methods(SEM). METHODS : SEM used in this study is a statistical technique for estimating causal relations using a combination of statistical data and qualitative causal assumptions. SEM allow exploratory modeling, meaning they are suited to theory development. The method is tested against the obtained measurement data to determine how well the model fits the data. Among the strengths of SEM is the ability to construct latent variables: variables which are not measured directly, but are estimated in the model from several measured variables. This allows the modeler to explicitly capture the unreliability of measurement in the model, which allows the structural relations between latent variables to be accurately estimated. RESULTS : The study results showed that causal factors could be grouped into 3. Factor 1 includes traffic variables, and Factor 2 contains turning traffic variables. Factor 3 consists of other road element variables such as speed limits or signal cycles. CONCLUSIONS : Non-linear regression models can be used to develop accident predictions models. However, they lack to estimate causal factors, because they select only few significant variables to raise the accuracy of the model performance. Compared to the regressions, SEM has merits to estimate causal factors affecting accidents, because it allows the structural relations between latent variables. Therefore, this study used SEM to estimate causal factors affecting accident at urban signalized intersections.

• 대한교통학회지
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• 제24권4호
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• pp.55-65
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• 2006

우리나라는 교통사고 사망자 가운데 보행자가 차지하는 비율이 43%로 매우 높으며, 이는 OECD평균의 2.5배에 이르는 수치이다 도로종류별 사고발생 특성을 보면 국도에서 보행자사고로 인한 사망자수 비율이 가장 높은 구성비를 차지하고 있다. 이에 따라 지방부 도로에서 보행자사고를 방지하기 위하여 보행자 관련 안전시설물 설치가 확대될 예정이다. 그러나 보행자 관련 연구가 주로 도시부 교차로를 대상으로 이루어짐에 따라 지방부 보행자사고 특성 분석에 대한 연구가 부족하고, 특히, 안전시설물의 보행자사고에의 효과에 대한 연구는 미미한 실정이다. 이에 본 연구에서는 지방부 4차로 국도를 대상으로 로짓모형을 이용하여 보행자사고 확률모형을 구축하고, 추정시 도로안전시설물 설치여부를 설명변수로 포함하여 그 효과도를 추정하였다. 시설물별 효과도는 승산비(Odds ratio)를 이용하여 비교위험I÷로 분석 제시하였다. 분석결과 시거개선, 보도설치, 조명설치가 보행자 사고를 줄이기 위한 효과적인 대안으로 나타났다.

• 한국항해항만학회지
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• 제36권9호
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• pp.715-720
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• 2012

This paper is to introduce the development of a LCD monitor-based pilots' ship handling simulator installed in the office of Korea Maritime Pilots Association. This simulator is composed of hardware which includes working server array, operation PC, monitor array, rudder, thruster and telegraph peripheral devices, and software which includes ship mathematical model software, ship conning software, image supporting software and so on. In this simulator, MMG mathematical model is used to create thirteen(13) ship models, which are based on sea trial data & pilots' opinion. According to requirements of pilots, virtual scenes of different port areas are built, and some required additional functions are also developed. By using this simulator, pilots can fulfill all kinds of training exercises, design of channel approaching ports, traffic safety analysis, prevention of accident research and other tasks, so as to grasp the characteristics of different ships, and accumulate experience for piloting.

• Nuclear Engineering and Technology
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• 제47권7호
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• pp.827-837
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• 2015

Following a severe accident in a nuclear power plant, iodine is a major contributor to the potential health risks for the public. Because the amount of iodine released largely depends on its volatility, iodine's behavior in containment has been extensively studied in international programs such as International Source Term Programme-Experimental Program on Iodine Chemistry under Radiation (EPICUR), Organization for Economic Co-operation and Development (OECD)-Behaviour of Iodine Project, and OECD-Source Term Evaluation and Mitigation. Korea Institute of Nuclear Safety (KINS) has joined these programs and is developing a simplified, stand-alone iodine chemistry model, RAIM (Radio-Active Iodine chemistry Model), based on the IMOD methodology and other previous studies. This model deals with chemical reactions associated with the formation and destruction of iodine species and surface reactions in the containment atmosphere and the sump in a simple manner. RAIM was applied to a simulation of four EPICUR tests and one Radioiodine Test Facility test, which were carried out in aqueous or gaseous phases. After analysis, the results show a trend of underestimation of organic and molecular iodine for the gas-phase experiments, the opposite of that for the aqueous-phase ones, whereas the total amount of volatile iodine species agrees well between the experiment and the analysis result.