• Fire Science and Engineering
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• v.19 no.1 s.57
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• pp.20-28
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• 2005

Major petrochemical companies in the USA and the EU map out the strategies step-by-step hazard evaluation for the efficient risk management. They adopted the risk screening methods, such as Dow fire & explosion index, as a preliminary phase to execute detailed evaluation such as QRA (Quantitative Risk Assessment). In this study, The FEDI (Fire & Explosion Damage Index), which a kind of risk screening method proposed by Khan and Abbasi, was applied to the BTX plant in Korea. We showed that the FEDI can be effectively used to classify the hazard potential by comparison of the result from the FEDI and the result from QRA. And we showed that the characteristics and the quantities of chemical are the factors which have a largest effect on fire and explosion by executing relative sensitivity analysis of the FEDI. In conclusion, if the FEDI was applied as a preliminary phase of HAZOP, more efficient hazard evaluation can be possible.

• Earthquakes and Structures
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• v.14 no.6
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• pp.577-587
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• 2018

The quantitative assessment of the seismic collapse risk of a structure requires the usage of an optimal intensity measure (IM) which can adequately characterise the severity of the ground motion. Research suggests that the average spectral acceleration ($Sa_{avg}$) may be an efficient and sufficient alternate IM as compared to the more traditional first mode spectral acceleration, $Sa(T_1)$, particularly during seismic collapse risk estimation. This study primarily presents a comparative evaluation of the sufficiency of the average spectral acceleration with respect to ground motion duration, and secondarily assesses the impact of ground motion duration on collapse risk estimation. By assembling a suite of 100 historical ground motions, incremental dynamic analysis of 60 different inelastic single-degree-of-freedom (SDF) oscillators with varying periods and ductility capacities were analysed, and collapse risk estimates obtained. Linear regression models are used to comparatively quantify the sufficiency of $Sa_{avg}$ and $Sa(T_1)$ using four significant duration metrics. Results suggests that an improved sufficiency may exist for $Sa_{avg}$ when the period of the SDF system increases, particularly beyond 0.5, as compare to $Sa(T_1)$. In reference to the ground motion duration measures, results indicated that the sufficiency of $Sa_{avg}$ is more sensitive to significant duration definitions that consider almost the full wave train of an accelerogram ($SD_{a5-95}$ and $SD_{v5-95}$). In order to obtain a reduced variability of the collapse risk estimate, the 5-95% significant duration metric defined using the Arias integral ($SD_{a5-95}$) should be used for seismic collapse risk estimation in conjunction with $Sa_{avg}$.

• Journal of the Korean Society of Safety
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• v.35 no.5
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• pp.22-29
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• 2020

In this study, combustion and smoke release characteristics of a non-class 1E cable for nuclear power plants were investigated according to aging period. The aging was reproduced through an accelerated aging method for interval of 10 years :10, 20, 30 and 40 year, which was applied the Arrhenius equation. The cable was subjected to accelerated aging. In order to understand combustion and smoke release characteristics, the cone calorimeter test was performed according to the standard code of KS F ISO 5660-1. Heat release rate, mass loss rate, average rate of heat emission and smoke production rate were examined through cone calorimeter test. Fire performance index, fire growth index and smoke factor were derived from test results for the comparison of quantitative fire risk. When comparing the fire performance index and the fire growth index, the early fire risk tends to decrease as aging progresses, which might be attributed from the fact that the volatile substances of cables were evaporated. However, when comparing the heat release rate, average rate of heat emission and mass loss rate, which represent the mid and late periods of the fire risk, the values of accelerated aging cables were much higher than those of non-aged cable, which signifies the unstable formation of the char layer resulted in the change in the performance of flame retardants. In addition, the results from the smoke characteristics show that the accelerated aging cables were lager than the non-aged cables in terms of overall fire risk. These results can be used as baseline data when assessing fire risk of cables and establishing fire safety code for nuclear power plants.

• Journal of the Korean Institute of Gas
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• v.11 no.2 s.35
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• pp.71-77
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• 2007

This research proposes the U-drawing information system (U-DIS) based on risk assessment. One of the most outstanding features of U-DIS is to perform the Quantitative Risk Assessment directly on the screen utilizing the Process Information. U-DIS revolutionizes the existing way to do a risk assessment and helps finding information more efficiently and simply. It is designed to open all CAD drawing files on the web-based environment without having the CAD S/W installed on the PC. The U terminal platform in U-DIS supports IPv6 and wireless broadband network and U-DIS can be accessible through a sensor or personal authorization. This results in providing a systematic safety enhancement tool considering not only the operation of the process but also its risk level in the equipment industry. Additionally to aid the decision making process it offers comprehensive and thorough information based on engineering technical theory.

• Journal of Breast Cancer
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• v.21 no.4
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• pp.391-398
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• 2018

Purpose: The aim of this study was to investigate the association of telomere length with breast cancer risk. We simultaneously explored the association between telomerase reverse transcriptase gene polymorphisms and telomere length. Methods: We used real-time quantitative polymerase chain reaction to measure relative telomere length (RTL) in genomic DNA extracted from peripheral blood from 183 breast cancer cases and 191 healthy controls. Genotyping was performed using the Sequenom MassARRAY platform. Results: Our results show that breast cancer patients had significantly shorter RTLs than control subjects (p<0.05). When the RTLs were categorized into tertiles, we found that the lowest RTL was significantly associated with increased breast cancer risk compared with the highest RTL (odds ratio [OR], 2.33; 95% confidence interval [CI], 1.40-3.90; p=0.001). Subgroup analyses indicated that risk of breast cancer was also significantly increased in the lowest RTL compared with the highest RTL in age >40 years (OR, 2.41; 95% CI, 1.31-4.43;p=0.005), body mass index ${\leq}24kg/m^2$ (OR, 2.81; 95% CI, 1.55-5.10; p=0.001), and postmenopausal women (OR, 3.94; 95% CI, 1.63-9.51; p=0.002), respectively. In addition, individuals with the AA genotype of rs2853677 have longer telomeres than those of breast cancer patients with the AG genotype (p=0.011). Conclusion: Our results suggest that shorter RTL was associated with an increased risk of breast cancer. An association was found between the AA genotype of rs2853677 and longer RTLs in the case group. Functional studies are warranted to validate this association and further investigate our findings.

• Journal of Korean Tunnelling and Underground Space Association
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• v.14 no.1
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• pp.1-22
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• 2012

This paper tried to verify whether the fixed fire fighting system (FFFS) that is installed in road tunnel improves evacuation performance or not. Verification was performed according to the Disaster Prevention Facilities Installation and Management Guide at Road Tunnel. Twenty seven different fire scenarios were set up for the verification and the cases that FFFS was installed were compared with the cases that FFFS was not installed. The result of the comparison showed that the average equivalent death was reduced in 26 cases out of 27 cases when water spray extinguishing system was installed. It was confirmed that the risk when was not installed was unacceptable in Hong Kong and the Netherlands. On the other hand, it was confirmed that the risk was reduced to as low as reasonably practicable (ALARP) when was installed. The cumulative frequency of average death in case with FFFS was compared against the frequency of death without FFFS: death of one or more is about 50 times less; 10 or more is about 100 times less; and the death of more than 100 is four times less. It was verified that FFFS makes improved conditions to escape from the fires in road tunnel.

• Journal of Korean Tunnelling and Underground Space Association
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• v.24 no.6
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• pp.539-552
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• 2022

In the case of train stations, due to the specificity of underground spaces with limited smoke emissions, if appropriate removal equipment is not equipped, the damage caused by fire smoke may increase in the event of a fire. As a result, the need for measures to ensure the safety of evacuation of underground stations has been highlighted, and research for safe evacuation of platform users in case of fire is continuously being conducted at home and abroad. However, although the smoke removal area is currently divided by smoke boundary walls and platform screen doors (PSD) and installed in the train platform, standards for smoke removal methods (air supply or exhaust) for each fire removal area, that is, smoke removal mode, are not presented. In this study, fire analysis and evacuation analysis were performed to estimate the number of deaths and to derive F/N guidance in order to quantitatively evaluate the fire risk according to the fire station fire, and the total risk was the lowest in the case of fire area exhaust and supply to adjacent areas.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.8 no.6
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• pp.1284-1290
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• 2004

In market-basket analysis, weighted association rule(WAR) discovery can mine the rules which include more beneficial information by reflecting item importance for special products. However, when items are divided into more than one group and item importance for each group must be measured by different measurement or separately, we cannot directly apply traditional weighted association rule discovery. To solve this problem, we propose a novel methodology to discovery the weighted association rule in this paper In this methodology, the items should be first divided into sub-groups according to the properties of the items, and the item importance is defined or calculated only with the items enclosed to the sub-group. Our algorithm makes qualitative evaluation for network risk assessment possible by generating risk rule set for risk factor using network sorority data, and quantitative evaluation possible by calculating risk value using statistical factors such as weight applied in rule generation. And, It can be widely used for new model of more delicate analysis in market-basket database in which the data items are distinctly separated.

• Journal of Dental Anesthesia and Pain Medicine
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• v.22 no.6
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• pp.405-417
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• 2022

Oral lichen planus (OLP) is a chronic inflammatory immune-mediated condition that has been identified as a potentially malignant oral disorder. Various therapies have been proposed for its management as alternative to corticosteroids. However, no definitive treatment has been identified that can result in complete remission or minimal recurrence. Hyaluronic acid has recently been used as an alternative therapy for the management of OLP. This study aimed to systematically review the effectiveness of Hyaluronic acid in the management of symptomatic OLP. Online electronic databases and manual searches were performed for randomized controlled trials (RCTs) published in English between January 2010 and April 2022. RCTs were identified that compared the efficacy of hyaluronic acid and other interventional therapies at baseline and during follow-up. The Cochrane Risk of Bias tool was used to assess the quality of the included studies. Visual analog scale (VAS) scores, Thongprasom sign scores, lesion size, degree of erythema, clinical severity, and disease severity were assessed both quantitatively and qualitatively. Seven studies were analyzed. Five studies reported a high risk of bias while the remaining two studies reported an unclear risk of bias. The overall quantitative assessment of size, symptoms, degree of erythema, and sign score in OLP lesions treated with HA was not statistically significant compared to that in the control group (P > 0.05). In addition, subgroup analysis comparing HA with placebo or corticosteroids did not yield statistically significant (P > 0.05) results. Qualitatively, both HA and tacrolimus resulted in an effective reduction in signs and symptoms. Clinical/disease severity index/scores were inconsistent. A high degree of heterogeneity was observed among the included studies. None of the included studies reported the side effects of HA. These findings suggest that corticosteroids, tacrolimus, placebo, and HA could be equally effective in OLP management. The clinical/disease severity index or score reduction cannot be determined with certainty. Thus, OLP can be treated with HA as an alternative therapy. Owing to limited clinical trials on HA, high heterogeneity, and high risk of bias in the included studies, definitive conclusions cannot be derived.

• Journal of Food Hygiene and Safety
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• v.29 no.4
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• pp.305-311
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• 2014

Minimum infective dose (MID) data has been recognized as an important and absolutely needed in quantitative microbiological assessment (QMRA). In this study, we performed a comprehensive literature review and meta-analysis to better quantify this association. The meta-analysis applied a final selection of 82 published papers for total 12 species foodborne disease pathogens (bacteria 9, virus 2, and parasite 1 species) which were identified and classified based on the dose-response models related to QMRA studies from PubMed, ScienceDirect database and internet websites during 1980-2012. The main search keywords used the combination "food", "foodborne disease pathogen", "minimum infective dose", and "quantitative microbiological risk assessment". The appropriate minimum infective dose for B. cereus, C. jejuni, Cl. perfringens, Pathogenic E. coli (EHEC, ETEC, EPEC, EIEC), L. monocytogenes, Salmonella spp., Shigella spp., S. aureus, V. parahaemolyticus, Hepatitis A virus, Noro virus, and C. pavum were $10^5cells/g$ (fi = 0.32), 500 cells/g (fi = 0.57), $10^7cells/g$ (fi = 0.56), 10 cells/g (fi = 0.47) / $10^8cells/g$ (fi = 0.71) / $10^6cells/g$ (fi = 0.70) / $10^6cells/g$ (fi = 0.60), $10^2{\sim}10^3cells/g$ (fi = 0.23), 10 cells/g (fi = 0.30), 100 cells/g (fi = 0.32), $10^5cells/g$ (fi = 0.45), $10^6cells/g$ (fi = 0.64), $10{\sim}10^2particles/g$ (fi = 0.33), 10 particles/g (fi = 0.71), and $10{\sim}10^2oocyst/g$ (fi = 0.33), respectively. Therefore, these results provide the preliminary data necessary for the development of foodborne pathogens QMRA.