• Journal of the Korean Institute of Gas
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• v.9 no.4 s.29
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• pp.57-61
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• 2005

The objective of paper is to carry out a comparative Quantitative Risk Assessment (QRA) of two KOGAS tank designs using a fault tree methodology, a standard 'Full Containment' tank and a 'Membrane' tank. For the membrane tank, both the initial KOGAS design and 4 modified KOGAS designs have been assessed, giving six separate cases. In this paper, the frequencies of releases are quantified using a fault tree approach. For clarity in the analysis, and to ensure consistency, all cases have been quantified using the same fault tree. Logic within the fault tree is used to select each of the cases. Full quantification of risks is often difficult, owing to a lack of relevant failure data, but the aim of this study has been to be as quantitative as possible, with full transparency of failure information. The most significant general cause of external LNG leaks is predicted to be a seismic event, which has been quantified nominally. 4modified KOGAS desiens to Prevent damage of bottom membrane panels that was shown in preparatory estimation could quantitively confirm safety improvement. According to result, the predicted frequencies of an external LNG leak for the full containment and modified membrane tanks are very similar, failures due to dropped pumps are predicted to be significantly greater for the membrane tank with thickened plate than for the full containment tank.

• Journal of the Society of Disaster Information
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• v.17 no.2
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• pp.206-217
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• 2021

Purpose: Recently, a series of large social disasters have led to a lot of research to prevent social disasters as well as natural disasters and reduce damage. However, this paper aims to select the types of social disasters that local governments should focus on and create basic data for effective countermeasures and mitigation efforts. Method: Among 43 types of disasters announced by the Ministry of Public Administration and Security, 11 types of disasters were selected and collected to select the main types of disasters, and risk types were derived by region with risk maps. In order to derive the risk map, each detailed index was rescheduled to be 0-1 and weights were determined through entropy technique. Result: As a result, about 41% of the major disasters announced by the Ministry of Public Administration and Security were consistent, and the rest of the major types were disasters that could not be obtained or have not occurred in the past 20 years. Conclusion: Therefore, in order to establish an effective prevention and recovery plan for social disasters through this study, it was intended to present social disaster-focused disasters for each local government.

• Fisheries and Aquatic Sciences
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• v.25 no.12
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• pp.626-636
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• 2022

Shellfish are exoskeleton-bearing aquatic invertebrates that consume various organic and inorganic substances floating in seawater through filter feeding. Heavy metals are known as absorbed and accumulated in seawater. Some of the toxic heavy metals are highly accumulated in seawater, and exposure to them can cause a variety of risks to the human body. Since Koreans like to eat seafood, they are more likely to be exposed to contaminated seafood with heavy metals. In this study, nine types of heavy metals were analyzed on ten different shellfish species in the coastal area of South Korea. The risk assessment was also done on shellfish in which heavy metals were detected. Zinc (Zn) and copper (Cu) were identified at an average of 56.7 mg/kg (6.70 to 466 mg/kg) and 13.2 mg/kg (0.064 to 143 mg/kg), respectively. Lead (Pb) average of 0.208 mg/kg (0.000750 to 1.02 mg/kg), cadmium (Cd) average of 0.454 mg/kg (0.0388 to 1.56 mg/kg) and mercury (Hg) average of 0.0266 mg/kg (0.00548 to 0.174 mg/kg) were identified. Additionally, arsenic (As), chromium (Cr), nickel (Ni), and silver (Ag) were also identified as average concentrations of 4.02 (0.460 to 15.0 mg/kg), 0.167 (< limit of quantification [LOQ] to 0.820 mg/kg), 0.281 (< LOQ to 1.46 mg/kg), and 0.158 mg/kg (< LOQ to 1.15 mg/kg). The result indicates that the monitoring results of heavy metals in most shellfish satisfied the Korean standard. However, Pb and Cd have exceeded some foreign standards, such as the United States and the EU. The permissible human exposure calculated using the heavy metal intake and detection amount was lower than the Joint FAO/WHO Expert Committee on Food Additives human safety standard, and the risk of heavy metals from shellfish consumption was at an acceptable level.

• Journal of Korea Water Resources Association
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• v.40 no.5
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• pp.383-396
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• 2007

The studies on efficiency of flood control reservoir has been introduced into four categories including direct flood control contribution by reservoir, flow-duration change and environmental-ecological change in downstream of dam and flood damage estimation of flood plain. In spite of all the previous approaches, the quantification of the effect of reservoir on the flood control in planning stage is quite complex due to lack of a standard for quantifying feasibility of project. In this study, we develop a methodology that can clearly and accurately quantify the flood damage reduction together with the existing flood level reduction at downstream. The proposed approach uses three appraisal standards of flood control: 'potential safety', 'relative risk' and 'absolute risk' according to the risk by stage. The developed methodology was applied to the Namhan river basin with the storm event of July, 2006. The result shows the damage reduction of 4,189 billion won was estimated. The economic benefits for the flood control effect by dam will greatly contribute to the public understanding of the importance and the effect of the flood control by dam.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.3
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• pp.235-241
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• 2012

A huge marine accident causes a loss of valuable lives, property and the serious marine environment pollution. IMO adopted resolution A.949(23) to provide Places of Refuge(PoR) to 'Ship in need of assistance', which is to minimize the secondary environmental pollution caused by marine accidents. If the level of risk exceeds a certain range, it is necessary to be designated as Places of Refuge(PoR) after evaluation of potential risk, which is based on the database of several marine environmental factors. Also, it is necessary to develop skills about quantification/standardization of vessel traffic safety, complexity and risk. Because there is the close relation between the problem of designating Places of Refuge(PoR) and the policy of nation for protecting the natural environment of coastal state, it is important to prepare related legislation. In this paper, introduction of Places of Refuge(PoR) in domestic areas have been suggested based on the analysis of several foreign designating cases.

• Journal of Korean Society of Environmental Engineers
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• v.38 no.7
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• pp.371-376
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• 2016

In this study, the survey of bisphenol-A in indoor water service pipes rehabilitated with epoxy resin was conducted and the risk assessment was done to investigate the effect on the human health to drink tap water. Bisphenol-A in raw water was detected in a range of 50~118 ng/L in all samples, where the limit of quantification was 10 ng/L. This is caused by inflow of the sewage effluent or the tributaries of the surrounding area containing bisphenol-A. Bisphenol-A was not detected in finished water after the advanced water treatment process. It was achieved by its removal from the processes of flocculation-precipitation and oxidation of ozone and chlorine and by being changed to other by-product materials. For the indoor water service pipe, bisphenol-A was not detected in all cases which was not coated with epoxy resin. However, when epoxy resin is lined within the indoor water service pipe, bisphenol-A was identified at maximum level of 521 ng/L and was detected above the limit of quantitation at 68 percentages of all samples. The Hazard Quotient (HQ) at the maximum level (521 ng/L) of the detected bisphenol-A is 0.004, which is less than the reference value of 0.1 for the tap water intake. Therefore, it is considered that the detected levels of bisphenol-A in this study would be safe to drink tap water.

• Journal of the Korea Institute of Information Security & Cryptology
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• v.23 no.3
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• pp.445-457
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• 2013

This paper is about the study to build a quantitative methodology to assess cyber threats and vulnerabilities on control systems. The SCADA system in power industry is one of the most representative and biggest control systems. The SCADA system was originally a local system but it has been extended to wide area as both ICT and power system technologies evolve. Smart Grid is a concept to integrate energy and IT systems, and therefore the existing cyber threats might be infectious to the power system in the integration process. Power system is operated on a real time basis and this could make the power system more vulnerable to the cyber threats. It is a unique characteristic of power systems different from ICT systems. For example, availability is the most critical factor while confidentiality is the one from the CIA triad of IT security. In this context, it is needed to reflect the different characteristics to assess cyber security risks in power systems. Generally, the risk(R) is defined as the multiplication of threat(T), vulnerability(V), and asset(A). This formula is also used for the quantification of the risk, and a conceptual methodology is proposed for the objective in this study.

• Journal of Environmental Impact Assessment
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• v.24 no.6
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• pp.549-560
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• 2015

The priorities of siting restriction was derived from quantification of environmental hazard according to industrial classification based on 'Chemical Ranking and Scoring System(CRS)' which is handling the discharge characteristics of 31 industrial classifications regulated from locating at 'Industrial Complex in Rural Area(ICRA)'. CRS that is utilizing the data of 'Pollutant Release and Transfer Registers(PRTR)' is applied to determine human health risk and ecological risk which are calculated by discharged amount and materials $LC_{50}$ according to water, soil and air media based on industrial classification. From this process, exposure assessment and toxicity assessment for integrating the adverse environmental impact and the mitigation effect of environmental risk according to the development of environmental technologies into establishing the rational landuse management method for the 31 industrial classifications regulated from locating at ICRA was analyzed. From the assessment result of the siting restriction removal at ICRA for 31 industrial classifications, based on 2012 year reference 6 industries that includes Manufacture of Guilt Coloration Surface Processing Steel Materials, Manufacture of Biological Product, Manufacture of Smelting Refining and Alloys of Copper, Dyeing and Finishing of Fibers and Yarns, Manufacture of Other Basic Iron and Steel n.e.c., Rolling Drawing and Extruding of Non-ferrous Metals n.e.c. are calculated as having relatively lower environmental hazards, thus it is judged that the siting restriction mitigation at ICRA is possible for the 6 industrial classifications that are not discharging the specific hazardous water contaminants during manufacturing process.

• Korean Journal of Applied Biomechanics
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• v.17 no.4
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• pp.99-106
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• 2007

The gait instability in the elderly has been associated with age-related deterioration in physical strength and reducing the potential for elderly falls requires regular exercise. In 2005, National Center for Injury Prevention and Control(NCIPC) reported that most elderly falls occur during activities in daily living(ADL). To better reveal biomechanic mechanisms underlying age-related degeneration in gait stability, and to enhance the assessment of falls risk, an accurate quantification of a person's balance maintenance during locomotion is needed. Instantaneous orientation of the line connecting COP and COM can characterize whole body position with respect to the supporting foot during gait and the angle between this line and the vertical line passing through the COP known as a good assessment to detect the elderly gait instability. Therefore the purpose of this study was to investigate a 6-month walking exercise effects in reducing elderly fall risk factors by using COP-COM inclination angles. Twenty-two community-dwelling elderly participated this study. The participants performed a walking exercise(3 times/week, 1 hour/visit) for 6 months. Laboratory kinematics during walking was assessed at months 0, 3 and 6. Significant increased in gait velocity was found among periods(p=.011, $1.25{\pm}.03$, $1.32{\pm}.03$, and $1.39{\pm}.04\;m/s$ in 0-, 3-, and 6-month, respectively). Also, significant differences in anterior and posteriror inclination angles were found among the periods(p<.05; posterior inclination angles: $12.8{\pm}2.2$, $11.0{\pm}2.9$, & $10.9{\pm}1.9$; anterior inclination angles: $13.7{\pm}1.7$, $14.6{\pm}3.2$, & $1.46{\pm}.21$ in 0month, 3month, & 6month, respectively). These findings provide evidence of significant reduced fall risk factors of community-living older adults associated with a systematic walking program.

• Korean Journal of Pharmacognosy
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• v.53 no.3
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• pp.162-169
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• 2022

This study investigated the mycotoxins (aflatoxin B₁, B₂, G₁, G₂, fumonisin B₁, B₂, ochratoxin A and zearalenone) contained in edible and medicinal plants in Seoul Yangnyeong market during 2020-2021. We analyzed contamination of mycotoxins using LC-MS/MS and evaluated risk assessment. The method was validated by assessing matrix effects, linearity, limit of detection (LOD), limit of quantification(LOQ) and recovery. Matrix-matched standard calibration was used for calibration curves showed good linearity (r²>0.999). The LOD, LOQ and recovery were 0.01-0.23 ㎍/kg, 0.04-0.71 ㎍/kg and 75.5-117.9% respectively. Mycotoxins were detected in 22 of 171 samples; aflatoxin B₁ (6.66 ㎍/kg), fumonisin (7.54-64.68 ㎍/kg), ochratoxin A (4.21-10.56 ㎍/kg) and zearalenone (7.31-60.76 ㎍/kg). In the risk assessment, the MOE (Margine of Exposure) of aflatoxin B₁ and ochratoxin A were in the range of 1.48×10³-2.36×10⁵. No items exceeded 100% in %TDI (Tolerable Daily Intake) of fumonisin (B₁+B₂) and zearalenone.