• Journal of Korean Society of Industrial and Systems Engineering
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• v.13 no.21
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• pp.29-41
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• 1990

An assessment of risk in industrial and urban environments is essential in the prevention of accident and in the analysis of situations which are hazardous to public health and safety. The risk imposed by a particular hazard increases with the likelihood of occurence of the event, the exposure and the possible consequence of that event. In a traditional approach, the calculation of a quantitative value of risk is usually based on an assignment of numerical values of each of the risk factors. Then the product of the values of likelihood, exposure and consequences called risk score is derived. However vagueness and imprecision in mathematical quantification of risk are equated with fuzziness rather than randomness. In this paper, a fuzzy set theoretic approach to risk analysis is proposed as an alternative to the techniques currently used in the area of systems safety. Then the concept of risk evaluation using linguistic representation of the likelihood, exposure and consequences is introduced. A risk assessment model using approximate reasoning technique based on fuzzy logic is presented to drive fuzzy values of risk and numerical example for risk analysis is also presented to illustrate the results.

• Proceedings of the Korean Society of Toxicology Conference
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• 2006.11a
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• pp.34-45
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• 2006

Chemical toxicants are metabolically converted to numerous metabolites in the body. Toxicokinetic characteristics of metabolites could be therefore used as biomarker of exposure for human risk assessment. Biologically based dose response (BBDR) model was proposed for future direction of risk assessment. However, this area has not been developed well enough for human application. Benzo(a)pyrene (BP), for example, is a well-known environmental carcinogen and may produce more than 100 metabolites and BPDE-DNA adduct, a covalently bound form of DNA with benzo(a)pyrene diolepoxides (BPDES), has been applied to qualitatively or quantitaively estimate human exposure to BP. In addition, di(2-ethylhexyl) phthalate (DEHP), a widely used plasticize. in the polymer industry, is one of endocrine-disrupting chemicals (EDCs) and has been monitored in humans using urinary or serum concentrations of DEHP or its monomer MEHP for exposure and risk assessment. However, it is difficult to estimate the actual level of toxicants using these biomarkers in humans using. This presentation will discuss a methodology of exposure and risk assessment by application of metabolic profiling kinetics.

• Journal of Food Hygiene and Safety
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• v.30 no.2
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• pp.127-131
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• 2015

This study aimed to calculate the required sample size to monitor food items during risk assessment studies. Based on a data set from a previous study (2,400 data points for heavy metal assessment from 17 food items), the required sample size was estimated by using a single equation with the standard deviation value, error range, and 95%-99% confidence intervals. The required sample size was calculated with each of the heavy metals for the assessment. The results showed that cadmium, lead, and mercury of required sample sizes for further monitoring were range of 7-90, 7-1, 062, and 11-238, respectively. We found that the required sample size varied depending on the standard deviation of the previous monitoring data. This study provides a basic method to determine the minimum sample size required in food monitoring to devise practical sampling strategies.

• Asian Journal of Atmospheric Environment
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• v.7 no.2
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• pp.72-84
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• 2013

In the study, pollution levels of indoor polycyclic aromatic hydrocarbons (PAHs) in public facilities (vapor phase or particulate phase) were evaluated, and a health risk assessment (HRA) was carried out based on exposure scenarios. Public facilities in Korea covered by the law, including underground subway stations, funeral halls, child care facilities, internet cafes (PC-rooms), and exhibition facilities (6 locations for each type of facility, for a total of 48 locations), were investigated for indoor assessment. For the HRA, individual excess cancer risk (ECR) was estimated by applying main toxic equivalency factor (TEF) values suggested in previous studies. Among the eight public facilities, internet cafes showed the highest average $PM_{2.5}$ concentration at $110.0{\mu}g/m^3$ (range: $83.5-138.5{\mu}g/m^3$). When assuming a risk of facility exposure time based upon the results of the surveys for each public facility, the excess cancer risk using the benzo(a)pyrene indicator assessment method was estimated to be $10^{-7}-10^{-6}$ levels for each facility. Based on the risk associated with various TEF values, the excess cancer risk based upon the seven types cancer EPA (1993) and Malcolm & Dobson's (1994) assessment method was estimated to be $10^{-7}-10^{-5}$ for each facility. The excess cancer risk estimated from the TEF EPA (2010) assessment was the highest: $10^{-7}-10^{-4}$ for each facility. This is due to the 10-fold difference between the TEF of dibenzo(a,e)fluoranthene in 2010 and in 1994. The internet cafes where smoking was the clear pollutant showed the highest risk level of $10^{-4}$, which exceeded the World Health Organization's recommended risk of $1{\times}10^{-6}$. All facilities, with the exception of internet cafes, showed a $10^{-6}$ risk level. However, when the TEFs values of the US EPA (2010) were applied, the risk of most facilities in this study exceeded $1{\times}10^{-6}$.

• Journal of Navigation and Port Research
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• v.42 no.2
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• pp.97-106
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• 2018

Despite the development of safety measures and improvements in preventive systems technologies, maritime traffic accidents that involve ships carrying hazardous and noxious substances (HNS) continuously occur owing to increased amount of HNS goods transported and the growing number of HNS fleet. To prevent maritime traffic accidents involving ships carrying HNS, this study proposes an intuitive route risk assessment technique using risk contours that can be visually and quantitatively analyzed. The proposed technique offers continuous information based on quantified values. It determines and structures route risk factors classified as absolute danger, absolute factors, and influential factors within the assessment area. The route risk is assessed in accordance with the proposed algorithmic procedures by means of contour maps overlaid on electronic charts for visualization. To verify the effectiveness of the proposed route risk assessment technique, experimental case studies under various conditions were conducted to compare results obtained by the proposed technique to actual route plans used by five representative companies operating the model ship carrying HNS. This technique is beneficial not only for assessing the route risk of ships carrying HNS, but also for identifying better route options such as recommended routes and enhancing navigation safety. Furthermore, this technique can be used to develop optimized route plans for current maritime conditions in addition to future autonomous navigation application.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.05a
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• pp.137-137
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• 2002

• Nuclear Engineering and Technology
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• v.53 no.11
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• pp.3465-3473
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• 2021

For a long time, research into integrated deterministic-probabilistic safety assessment has been continuously conducted to point out and overcome the limitations of classical ET (event tree)/FT (fault tree) based PSA (probabilistic safety assessment). The current paper also attempts to assert the reason why a technical transformation from classical PSA is necessary with a re-interpretation of the categories of risk. In this study, residual risk was classified into interpolating- and extrapolating-censored categories, which represent risks that are difficult to identify through an interpolation or extrapolation of representative scenarios due to potential nonlinearity between hardware and human behaviors intertwined in time and space. The authors hypothesize that such risk can be dealt with only if the classical ETs/FTs are freely relocated, entailing large-scale computation associated with physical models. The functional elements that are favorable to find residual risk were inferred from previous studies. The authors then introduce their under-development enabling techniques, namely DICE (Dynamic Integrated Consequence Evaluation) and DeBATE (Deep learning-Based Accident Trend Estimation). This work can be considered as a preliminary initiative to find the bridging points between deterministic and probabilistic assessments on the pillars of big data technology.

• Proceedings of the SAREK Conference
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• 2008.11a
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• pp.67-70
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• 2008

As a part of the project on road tunnel fire safety system development, Quantitative Risk Assessment program was developed. In this study, We carried out Quantitative Risk Assessment with this program by using a factor of cross passage interval, warning announcement time and congestion ratio etc for 1km tunnel with natural ventilation. In the case of 250m below of cross passage interval, Risk value due to warning announcement time was a slightly changed. but if cross passage interval is more than 250m, expected fatalities in the same HRR(heat release rate) was sharp increased. As a result, Quantitative Risk Assessment program which was developed in this research project is possible to risk assessment with ventilation type, cross passage for evacuation and detection system response property etc. hereafter, this program look forward to use as a tool for road tunnel performance based design.

• 대한예방의학회:학술대회논문집
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• 1994.02a
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• pp.469-475
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• 1994

This paper presents a brief survey of current methodology available for quantitative risk assessment of environmental carcinogens. Four current models for low-dose extrapolation are reviewed. Current problems and controversies and possible options in doing quantitative risk assessments based on chronic animal studies are discussed.

• Journal of Soil and Groundwater Environment
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• v.16 no.1
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• pp.32-41
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• 2011

By using a newly developed Korean risk-based corrective action (K-RBCA) software (K-RBCA) and the RBCA Tool Kit, risk assessment was performed on a site that was contaminated with aromatic hydrocarbons and heavy metals. Eight chemicals including benzene, ethylbenzene, xylenes, naphthalene, benz(a) anthracene, benzo(b) fluoranthene, benzo(a) pyrene, and arsenic that exceeded the US EPA Soil Screening Level were chosen as the target pollutants. A conceptual site model was constructed based on the site-specific effective exposure pathways. According to the RBCA Tool Kit the carcinogenic risk of arsenic was larger than $10^{-6}$, which is the generally acceptable carcinogenic risk level. The K-RBCA estimated the same level of carcinogenic risk for arsenic. With the RBCA Tool Kit, the carcinogenic risk of benzo(a) pyrene was estimated to be about $1.3{\times}10^{-6}$. However, with the K-RBCA benzo(a) pyrene did not exhibit any risk. The inconsistency between the softwares was attributed to the different fundamental settings (i.e., medium division) between the two softwares. While the K-RBCA divides medium into surface soil, subsurface soil, and groundwater, the RBCA Tool Kit divides medium into only soil and groundwater. These differences lead to the different exposure pathways used by the two softwares. The K-RBCA considers the exposure pathways in surface soil and subsurface soil separately to estimate risk, however, the RBCA Tool Kit considers the surface soil and subsurface soil as one and uses the integrated exposure pathways to estimate risk. Thus the resulting risk is higher when the RBCA Tool Kit is used than when the K-RBCA is used. The results from this study show that there is no significant difference in the risks estimated by the two softwares, thus, it is reasonable to use the K-RBCA we developed in risk assessment of soil and groundwater. In addition, the present study demonstrates that the assessor should be familiar with the characteristics of a contaminated site and the assumptions used by a risk assessment software when carrying out risk assessment.