• Korean Journal of Construction Engineering and Management
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• v.23 no.4
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• pp.15-25
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• 2022

As the incidence and mortality of serious disasters in the construction industry are the highest, various efforts are being made in Korea to reduce them. Among them, risk assessment is used as data for disaster reduction measures and evaluation of risk factors at the construction stage. However, the existing risk assessment involves the subjectivity of the performer and is vulnerable to the domestic construction site. This study established a DB classification system for risk assessment with the aim of early identification and pre-removal of risks by quantitatively deriving risk factors using BIM in the risk assessment field and presents a methodology for risk assessment using BIM. Through this, prior removal of risks increases the safety of construction workers and reduces additional costs in the field of safety management. In addition, since it can be applied to new construction methods, it improves the understanding of project participants and becomes a tool for communication. This study proposes a framework for deriving quantitative risks based on BIM, and will be used as a base technology in the field of risk assessment using BIM in the future.

• Journal of the Korean Institute of Gas
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• v.14 no.4
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• pp.18-23
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• 2010

After conducting QRA(quantitative risk assessment) for the high pressure urban gas pipelines planned to be installed, RMMs(risk mitigation measures) when the societal risk is outside the acceptable region have been derived in this paper. Also risk reduction rates are calculated for each RMM. As a result of QRA, we find out that damaged distance caused by radiational heat is largely dependent upon the wind velocity and the atmospheric stability. The measure that has the highest risk reduction effect is No. 10 which includes pipeline corrosion monitoring, MOV(motor operated valve) installation and the method to protect pipeline damage caused by third-party mechanical interference, and which shows 75 % of risk reduction effect.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.29 no.5
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• pp.1179-1189
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• 2019

Cyber security evaluation is a series of processes that estimate the level of risk of assets and systems through asset analysis, threat analysis and vulnerability analysis and apply appropriate security measures. In order to prepare for increasing cyber attacks, systematic cyber security evaluation is required. Various indicators for measuring cyber security level such as CWSS and CVSS have been developed, but the quantitative method to apply appropriate security measures according to the risk priority through the standardized security evaluation result is insufficient. It is needed that an Scoring system taking into consideration the characteristics of the target assets, the applied environment, and the impact on the assets. In this paper, we propose a quantitative risk assessment model based on the analysis of existing cyber security scoring system and a method for quantification of assessment factors to apply to the established model. The level of qualitative attribute elements required for cyber security evaluation is expressed as a value through security requirement weight by AHP, threat influence, and vulnerability element applying probability. It is expected that the standardized cyber security evaluation system will be established by supplementing the limitations of the quantitative method of applying the statistical data through the proposed method.

• Ocean Systems Engineering
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• v.12 no.3
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• pp.267-284
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• 2022

A subsea pipeline designed across active shipping lane prones to failure against external interferences such as anchorage activities, hence risk assessment is essential. It requires quantifying the geometric probability derived from ship traffic distribution based on Automatic Identification System (AIS) data. The actual probability density function from historical vessel traffic data is ideal, as for rapid assessment, conceptual study, when the AIS data is scarce or when the local vessels traffic are not utilised with AIS. Recommended practices suggest the probability distribution is assumed as a single peak Gaussian. This study compares several fitted Gaussian distributions and Monte Carlo simulation based on actual ship traffic data in main ship direction in an active shipping lane across a subsea pipeline. The results shows that a Gaussian distribution with five peaks is required to represent the ship traffic data, providing an error of 0.23%, while a single peak Gaussian distribution and the Monte Carlo simulation with one hundred million realisation provide an error of 1.32% and 0.79% respectively. Thus, it can be concluded that the multi-peak Gaussian distribution can represent the actual ship traffic distribution in the main direction, but it is less representative for ship traffic distribution in other direction. The geometric probability is utilised in a quantitative risk assessment (QRA) for subsea pipeline against vessel anchor dropping and dragging and vessel sinking.

• Journal of the Korean Society of Safety
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• v.23 no.2
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• pp.37-44
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• 2008

The safety assessment for facility industry is now being periodically performed. For the purpose of scientific safety management, QRA(Quantitative Risk Assessment) is also being performed, and reliability data of the facilities is essential to perform the assessment. Generally, the existing safety assessment is performed by using the values announced in other industry processes, which result in the drop of reliability. In order to solve this problem, there is an urgent need to establish reliability database for the facilities. The most appropriate method is to perform a direct reliability analysis towards the facilities undergoing safety assessment. In this study, in compliance with the assessment method and procedure of OREDA-2002 handbook, the facility reliability data are collected, which include the calendar time and operational time in terms of different facility items, the number of failures in terms of different failure mode, the mean, standard deviation, lower limit and upper limit of failure rate, and the failure rate. And the data process method for this special occasion is also proposed when the number of failure is 0.

• Journal of the Korean Society of Combustion
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• v.20 no.1
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• pp.1-5
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• 2015

Fire and explosion analysis are performed for the quantitative risk assessment on the LNG test plant. From the analysis for a case of fire due to large leakage of LNG from the tank, it is obtained that loss of lives can be occurred within the radius of 60 m from the fire origin. Specially, wind can extend the extent of damage. Because the LNG test plant is not enclosed, the explosion overpressure is less than 6 kPa and the explosion has little effect on the integrity of the LNG test plant.

• Journal of Environmental Impact Assessment
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• v.13 no.1
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• pp.1-8
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• 2004

A wide spectrum of risk assessments including qualitative and quantitative approaches and the analyses of its consequence were performed for an environmentally sensitive object such as incineration facility. To find out the major risk concerns, HAZOP(Hazard and Operability) were performed. Then, the frequency of hazardous gas release scenarios was calculated. Finally consequence analyses were performed for the gas release scenarios. On the basis of analyses through evaluation, a more innovative way for making a better control system or the enhancement of operation procedure was given. The results from these analyses would act as a substantial benefits for the incineration facility operator, and giving some measured information for the neighbors and the people involved.

• Journal of Animal Science and Technology
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• v.65 no.5
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• pp.1024-1039
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• 2023

In this study, we performed a quantitative microbial risk assessment (QMRA) of Salmonella through intake of egg consumption after cooking (dry-heat, moist-heat, and raw consumption). Egg samples (n = 201) from retail markets were analyzed for the presence of Salmonella. In addition, temperature and time were investigated during egg transit, storage, and display. A predictive model was developed to characterize the kinetic behavior of Salmonella in eggs, and data on egg consumption and frequency were collected. Eventually, the data was simulated to estimate egg-related foodborne illnesses. Salmonella was not found in any of the 201 egg samples. Thus, the estimated initial contamination level was -4.0 Log CFU/g. With R² values of 0.898 and 0.922, the constructed predictive models were adequate for describing the fate of Salmonella in eggs throughout distribution and storage. Eggs were consumed raw (1.5%, 39.2 g), dry-heated (57.5%, 43.0 g), and moist-heated (41%, 36.1 g). The probability of foodborne Salmonella illness from the consumption of cooked eggs was evaluated to be 6.8×10^-10. Additionally, the probability of foodborne illness not applied cooking methods was 1.9×10^-7, indicating that Salmonella can be reduced by cooking. Therefore, the risk of Salmonella infection through consumption of eggs after cooking might be low in S. Korea.

• 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.

• Environmental Engineering Research
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• v.14 no.2
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• pp.120-125
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• 2009

Water stress has become a major concern in agriculture. Korea suffers from limited agricultural water supply, and wastewater reuse has been recommended as an alternative solution.A study was performed to examine the effects of microorganism concentration in the ponded-water of a paddy rice field with reclaimed-water irrigation for evaluating the microbial risk to farmers and neighborhoodchildren.Most epidemiological studies were performed based on an upland field, and they may not directly applicable to paddy fields. Beta-Poisson model was used to estimate the microbial risk of pathogen ingestion. Their risk value increased significantly high level after irrigation and precipitation.It implies that agricultural activities such as plowing, and fertilizing, and precipitation need be practiced a few days after irrigation considering health risks. The results about field application of the microbial risk assessment using E. coli showed difference according to monitoring time and treatment plot. Result of the microbial risk assessment showed that risk values of ground-water and reclaimed secondary waste water irrigation were lower than directly use of wastewater treatment plants' effluent. This paper should be viewed as a first step in the application of quantitative microbial risk assessment of E. coli to wastewater reuse in a paddy rice farming.