• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.11-19
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• 2006

In this study ship collision risk analysis is performed to determine the design vessel for collision impact analysis of suspension bridge. Method II in AASHTO LRFD bridge design specifications which is a more complicated probability based analysis procedure is used to select the design vessel for collision impact. From the assessment of ship collision risk for each bridge pier exposed to ship collision, the design impact lateral strength of bridge pier is determined. The analysis procedure is an iterative process in which a trial impact resistance is selected for a bridge component and a computed annual frequency of collapse(AF) is compared to the acceptance criterion, and revisions to the analysis variables are made as necessary to achieve compliance. The acceptance criterion is allocated to each pier using allocation weights based on the previous predictions. This AF allocation method is compared to the pylon concentration allocation method to obtain safety and economy in results. This method seems to be more reasonable than the pylon concentration allocation method because AF allocation by weights takes the design parameter characteristics quantitatively into consideration although the pylon concentration allocation method brings more economical results when the overestimated design collision strength of piers compared to the strength of pylon is moderately modified. The design vessel for each pier corresponding with the design impact lateral strength obtained from the ship collision risk assessment is then selected. The design impact lateral strength can vary greatly among the components of the same bridge, depending upon the waterway geometry, available water depth, bridge geometry, and vessel traffic characteristics. Therefore more researches on the allocation model of AF and the selection of design vessel are required.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2022.06a
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• pp.389-390
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• 2022

Recently, Recently, the increase in international trade volume and the explosive increase in cargo volume due to the non-face-to-face society are leading to an increase in risk exposure and safety accidents in the port industry. In addition, as the Serious Disaster Punishment Act came into effect on January 27, 2021, various guidelines and laws to protect safety and life in port terminals are being enacted. However, despite these efforts, medium-to-large safety accidents in the port terminal industry continue to occur. According to the Korea Occupational Safety and Health Agency, from 2016 to 2019, the number of casualties in the port handling industry increased by 4.2%. For effective follow-up management of port accidents or the preparation of related safety laws/systems, a risk analysis in consideration of the cause and damage of the accident must be conducted first, so that realistic accident reduction and prevention measures can be established. Therefore, in this study, major risk factors and preventive measures were derived by conducting risk assessment based on 1,039 cases of port terminal accidents collected by the Korea Occupational Safety and Health Agency for 5 years from 2016 to 2022. After that, the priorities for preventive measures were determined through IPA analysis, Borich needs analysis, and The Locus For Focus analysis.

• Journal of The Korean Society of Agricultural Engineers
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• v.50 no.2
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• pp.11-16
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• 2008

The effects of water and pesticide management practices on ponded water pesticide concentrations in a paddy plot were analysed using the RICEWQ model. The molinate which is a herbicide widely used in rice culture, and frequently detected in paddy environment was selected. In a previous study, the RICEWQ model was successfully calibrated with field data obtained from a paddy plot in Daegu. The calibrated model was run using water and pesticide management scenarios with a set of measured meteorological data for 1997-2006 in Daegu. For all three ponded water depths with the label rate application, the amount of molinate dissipated in ponded water and volatilized accounted for more than 70%, and the runoff losses were less than 9%. The molinate losses through drainage in the very shallow ponded depth showed 40% less than that in deep ponded depth. Comparing with the deep and shallow ponded depth, the very shallow depth was the best with regards to the reduction of molinate runoff losses. Simulations with different pesticide application rates, label rate and double label rate, showed molinate concentrations in the ponded water increased linearly with the application rate increase.

• Journal of the Korean Society of Safety
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• v.29 no.4
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• pp.160-167
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• 2014

To determine a proper ASIL for each hazardous event with a proper safety goal, the right classes should first be determined for the three properties of the hazardous event; (i) severity of harm from the resultant accident, (ii) exposure to the relevant operational situation, and (iii) controllability to avoid the induced risks. ASIL can be clearly determined with right classes of these three properties. But no specific methodologies or processes for their classification can be found in ISO 26262, except only a rough guideline with a simplified set of illustrative tables. In this paper, we try to present a systematic model for classifying the three properties of the hazardous event and suggest a refined procedure of ASIL determination. The proposed model provides a specific method to get a more objective ASIL compared with that in the standard. Scrutinizing the current methodology, we develop a refined method and also provide an illustrative example.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2022.11a
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• pp.17-18
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• 2022

In Korea, asbestos removal has been actively carried out nationwide since 2015 when asbestos was completely banned as a first-class carcinogen. Since scattering dust generated in the process of removing asbestos causes fatal diseases such as asbestos lung disease and lung cancer, concerns are growing over the safety of construction workers and building users undergoing dismantling. For this reason, regulations on asbestos sites have been strengthened and prior studies on safety and risk assessment have been conducted, but research on actual site data collection and process planning is insufficient even though safety is reduced due to delay in site construction period. Therefore, it is necessary to analyze the work and delay factors of the asbestos dismantling process and develop an optimized process plan model for workers. This study is an initial step to develop an optimized process plan model that considers the safety and productivity of asbestos dismantling work, and aims to help establish an optimized process plan for asbestos dismantling process using website clone simulation.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.526-535
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• 2024

This paper proposes a safety-critical standby component unavailability model that contains aging effects caused by the elapsed time from installation, component degradation due to surveillance tests, and imperfect maintenance actions. An application of the model to a Motor-Operated Valve and a Motor-Driven Pump involved in the HPIS of a VVER/1000-V446 nuclear power plant is demonstrated and compared with other existing models at component and system levels. In addition, the effects of different unavailability models are reflected in the NPP's risk criterion, i.e., core damage frequency, over five maintenance periods. The results show that, compared with other models that do not simultaneously consider the full effects of degradation and maintenance impacts, the proposed model realistically evaluates the unavailabilities of the safety-related components and the involved systems as a plant age function. Therefore, it can effectively reflect the age-dependent CDF impact of a given testing and maintenance policy in a specified time horizon.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7789-7794
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• 2015

Background: This study aimed to evaluate the impact of a community-based health education and communication programme on reducing liver fluke infections caused by the consumption of uncooked fish among people in a high-risk area of Thailand. Materials and Methods: The study was quasi-experimental in nature, with three-stages. Stage 1 involved a situational and capacity analysis of designated communities in Khon Kaen province. This was followed by the development of a model for community-based health education and communication to prevent liver fluke infections among high-risk people, and, lastly, implementation and evaluation of the model were performed. Data were collected using both qualitative and quantitative methods. In total, 390 people were surveyed, and quasi-experimental and comparison groups, each with 90 people, were assessed between May 2011 and April 2012. Analysis was using statistical OR, 95 % CI, the Willcoxon matched pairs signed ranks test, the chi-square test, and the Mann-Whitney U test. Results: The findings showed that most respondents had a high level of knowledge and understanding of liver fluke disease (89.5%, 95% CI:86.0-92.4), and positive attitudes toward the prevention of the disease (94.4%, 95% CI:91.6-96.4). However, with regard to changes in consumption of uncooked fish, most respondents were still in the pre-contemplation phase (55.1%, 95% CI:50.0-60.1), followed by the contemplation phase, 22.6%. Furthermore, four factors were found to be associated with the consumption of uncooked fish - the consumption of alcohol (OR 4.16, 95% CI:1.79-9.65), gender (OR 3.17, 95% CI:1.53-6.54), smoking (OR 3.03, 95% CI:1.31-7.05), and age 40 years and above (OR 2.68, 95% CI:1.02-7.05). After nine months of the health education and communication programme using local media based on local wisdom, culture and persons, the results showed that, compared to the control group, members of the experimental group had a higher level of knowledge, a better attitude and lower levels of ill-advised consumption behaviour. Also, it was found that consumption of uncooked fish, by an assessment of the level of stage of change, was reduced. (p-value 0.002). Conclusions: The health education and communication programme developed as part of the study was effective in changing the consumption of uncooked fish. Therefore, this approach should be promoted in other high-risk areas in Thailand in the future.

• Journal of Navigation and Port Research
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• v.33 no.3
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• pp.181-191
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• 2009

In general, seafarer's human error is considered to be the preponderant muse for the majority of maritime transportation accidents in a merchant ship. The implementation techniques for Human Error Model (HEM) to assess possible accident risk by deck officers including captain, chief officer, second mate and third mate are described in this study. The scope of this work is focused to 642 deck officers in the ship management company with 130 vessels. At first, HEM can be constructed through the statistical analysis and expert's brainstorming process with human data to 642 deck officers. Then the variables $\upsilon$ for the human factors, the evaluation level EP($\upsilon$) for $\upsilon$, the weight $\alpha$ of $\upsilon$, and the title weight $\beta$ of each deck officers can be decided. In addition, through the analysis of ship's accident history, the accident causation ratios by human error ${\gamma}_H$ and by external error ${\gamma}_B$ can be found as 0.517(51.7%) and 0.483(48.3%), respectively. The correlation coefficients to $\upsilon$ are also shown significant for a 95% confidence interval (p < 0.05) for each coefficient. And the validity of HEM is also surveyed by the analysis of normal probability distribution of risk level RL to each deck officer.

• Economic and Environmental Geology
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• v.47 no.2
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• pp.133-146
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• 2014

There are many studies for the economic impact assessment of natural disasters, but there are few for volcanic disasters. Domestic academic research is not under active discussion because of the lack of national and social interest for volcanic eruption. This study investigated the research methodology for the economic impact assessment of natural disasters and discussed whether these can be applied to the economic impact analysis for the Baekdu Mountain volcanic disaster. The main findings are as follows: Firstly, Asia-Pacific region is the most affected by natural disasters and has the largest scale of damage. Asian and American Continent have the most economic damage. Secondly, Considering the types of damage caused by natural disasters and its complex structure, several methodologies that could be possible to estimate economic consequential damages have been compared. When applying each methodology to the Baekdu Mountain volcanic disaster, the scale of damage is likely to be over-estimated or under-estimated because of model-specific features. Thus, estimated values should be compared to each other after calculating the damage results. Thirdly, Japanese academic research on the volcanic disaster will be used as the starting point of the economic impact assessment studies for Baekdu Mountain. Using computer SW such as Hazus which is used in United States and RiskScape from New Zealand is also a good method to predict economic impact of the Baekdu Mountain volcanic disaster.

• Environmental Analysis Health and Toxicology
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• v.17 no.3
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• pp.197-205
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• 2002

Volatile organic compounds (VOCs) are an important public health problem throughout the world. Many important questions remain to be addressed in assessing exposure to these compounds. Because they are ubiquitous and highly volatile, special techniques must be applied in the analytical determination of VOCs. Personal exposure measurements are needed to evaluate the relationship between microenvironmental concentrations and actual exposures. It is also important to investigate exposure frequency, duration, and intensity, as well as personal exposure characteristics. In addition to air monitoring, biological monitoring may contribute significantly to risk assessment by allowing estimation of absorbed doses, rather than just the external exposure concentrations, which are evaluated by environmental and personal monitoring. This study was conducted to establish the analytic procedure of VOCs in air, blood, urine and exhaled breath and to evaluate the relationships among these environmental media. The subjects of this study were selected because they are occupationally exposed to high levels of VOCs. Environmental, personal, blood, urine and exhalation samples were collected. Purge ＆ trap, thermal desorber, gas chromatography and mass selective detector were used to analyze the collected samples. Analytical procedures were validated with the“break through test”, 'quot;recovery test for storage and transportation”,“method detection limit test”and“inter-laboratory QA/QC study”. Assessment of halogenated compounds indicted that they were significantly correlated to each other (p value < 0.01). In a similar manner, aromatic compounds were also correlated, except in urine sample. Linear regression was used to evaluate the relationships between personal exposures and environmental concentrations. These relationships for aromatic and halogenated are as follows: Halogen $s_{personal}$ = 3.875+0.068Halogen $s_{environmet}$, ($R^2$= .930) Aromatic $s_{personal}$ = 34217.757-31.266Aromatic $s_{environmet}$, ($R^2$= .821) Multiple regression was used to evaluate the relationship between exposures and various exposure deter-minants including, gender, duration of employment, and smoking history. The results of the regression model-ins for halogens in blood and aromatics in urine are as follows: Halogen $s_{blood}$ = 8.181+0.246Halogen $s_{personal}$+3.975Gender ($R^2$= .925), Aromatic $s_{urine}$ = 249.565+0.135Aromatic $s_{personal}$ -5.651 D.S ($R^2$ = .735), In conclusion, we have established analytic procedures for VOC measurement in biological and environmental samples and have presented data demonstrating relationships between VOCs levels in biological media and environmental samples. Abbreviation GC/MS, Gas Chromatography/Mass Spectrometer; VOCs, Volatile Organic Compounds; OVM, Organic Vapor Monitor; TO, Toxic Organicsapor Monitor; TO, Toxic Organics.