• Journal of the Computational Structural Engineering Institute of Korea
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• v.37 no.3
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• pp.205-216
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• 2024

Recently, seismic Probabilistic Safety Assessment (PSA) methods have been developed for process plants, such as gas plants, oil refineries, and chemical plants. The framework originated from the PSA of nuclear power plants, which aims to assess the risk of reactor core damage. The original PSA method was modified to adopt the characteristics of a process plant whose purpose is continuous operation without shutdown. Therefore, a fault tree, whose top event is shut down, was constructed and transformed into a Bayesian Network (BN), a probabilistic graph model, for efficient risk-informed decision-making. In this research, the fault tree-based BN from the previous research is further developed to consider the multi-hazard of earthquake-induced fire and explosion (EQ-induced F&E). For this purpose, an event tree describing the occurrence of fire and explosion from a release is first constructed and transformed into a BN. And then, this BN is connected to the previous BN model developed for seismic PSA. A virtual plot plan of a gas plant is introduced as a basis for the construction of the specific EQ-induced F&E BN to test the proposed BN framework. The paper demonstrates the method through two examples of risk-informed decision-making. In particular, the second example verifies how the proposed method can establish a repair and retrofit strategy when a shutdown occurs in a process plant.

• Journal of Environmental Science International
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• v.23 no.7
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• pp.1277-1287
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• 2014

As concerns have been raised about health effects of children's products containing hazardous chemicals on children, the Korea Ministry of Environment announced 135 environmental hazardous substances in children's products (EHSCP) which were subject to risk assessment. Therefore, it is necessary to identify the current status of EHSCP for management due to their various exposure routes and types. In this study, we investigated the exposure assessment of EHSCP as well as relevant policies implemented in domestic and foreign countries. Domestic and foreign cases of detection of EHSCP were reviewed in the literature and websites of related agencies. Due to the lack of reference values for child-specific toxicity of EHSCP, those for adults and regulatory status of EHSCP were also investigated and reviewed with literature. The related agencies of foreign countries provided 13 child-specific reference doses (RfDs), 76 RfDs, and 42 reference concentrations as toxicity reference values of the EHSCP. Among substances investigated in the studies to assess exposure of hazardous substances in children's products by the Korea Ministry of Environment, 23 substances were included in 135 EHSCP. The same studies identified 9 substances which were excluded from the 135 EHSCP. For regulatory status for hazardous substances in children's products, 44 substances (32.6 %) and 84 substances (62.2 %) of 135 EHSCP were under regulation in Korea and foreign countries, respectively. In the present study, we found that a list of 135 EHSCP should be revised to ensure children's safety.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.6
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• pp.597-605
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• 2013

This study was conducted in warty sea squirt farm, Jindong Bay(10 stations; July, October, January, April) for the culture period of Styela clava, Styela plicata. We utilized water temperature, chlorophyll a, suspended particulate matter, hydrodynamics, salinity and dissolved oxygen saturation for the suitability assessment of warty sea squirt farm. Newly, Life Requisite Suitability graphs were made for the correlation between the growth of Styela clava, Styela plicata and farm environment. As a result of the assessment for Habitat Suitability Index, western bay(HSI 0.32~0.41) show values higher than eastern bay(HSI 0.19~0.27). This result shows the high correlation with the unit production of Styela clava, Styela plicata($R^2$=0.834, P<0.01). This could be helpful for fishery management for the sustainable productivity through the scientific suitable site assessment.

• Nuclear Engineering and Technology
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• v.49 no.4
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• pp.801-809
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• 2017

The purpose of this study is to assess the additional neutron effective dose during passive scattering proton therapy. Monte Carlo code (Monte Carlo N-Particle 6) simulation was conducted based on a precise modeling of the National Cancer Center's proton therapy facility. A three-dimensional neutron effective dose profile of the interior of the treatment room was acquired via a computer simulation of the 217.8-MeV proton beam. Measurements were taken with a $^3He$ neutron detector to support the simulation results, which were lower than the simulation results by 16% on average. The secondary photon dose was about 0.8% of the neutron dose. The dominant neutron source was deduced based on flux calculation. The secondary neutron effective dose per proton absorbed dose ranged from $4.942{\pm}0.031mSv/Gy$ at the end of the field to $0.324{\pm}0.006mSv/Gy$ at 150 cm in axial distance.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.22 no.1
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• pp.1-8
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• 2012

Objectives: The aim of this study is to review occupational hygiene activities, including work environment measurement as required by the industrial safety and health laws of Korea, and suggest improvements required to establish an effective exposure surveillance system. Methods: The controversial limitations of exposure surveillance examining the work-association of several types of cancers in semiconductor workers were reviewed. Results: The bulk of the exposure surveillance system was found to focus purely on work environment measurements without providing other important exposure surrogates, such as job title, operation, exposure duration, etc. The current work environment measurement system is limited in terms of the efficient assessment of the exposure status of workers due to a lack of exposure information. Conclusion: The introduction of a national standard classification of occupations and job titles into the exposure and health effect surveillance system should be discussed in order to retrospectively assess exposure characteristics.

• The Korean Journal of Mycology
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• v.49 no.3
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• pp.393-397
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• 2021

The unrecorded fungus Galactomyces pseudocandidus de Hoog & M.T. Sm. was isolated and cultured from an introduced species, Procambarus clarkii, in Korea. Two related species, Galactomyces citri-aurantii and Geotrichum candidum, have been reported, but no other Galactomyces spp. have been found in Korea. In this study, we isolated G. pseudocandidus from the digestive tract of American crayfish using RGY (river water-glucose-yeast) medium and then compared the morphological and molecular characteristics of this species with those of related species. As a result, we confirmed that G. pseudocandidus is an unrecorded fungus in Korea, so we described and reported the cultural characteristics and microstructures, such as conidia.

• Journal of the Korean Society of Marine Environment & Safety
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• v.19 no.3
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• pp.257-263
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• 2013

The classification of risk factors and the identification of risk acceptance criteria are core works to assess risk levels with high enough confidential level in the field of marine traffic environment. In the previous study work, the twenty kinds of risk factors and its assessment criteria for the domestic marine traffic environment were proposed. In this paper, with these previous studying results, the relative importance of the risk factors were analyzed by questionnaire survey of marine traffic experts using the analytic hierarchy process. The analysis results showed that the relative importance of the visibility restriction is the highest among the twenty kinds of risk factors, and the relative importance of the traffic condition is the highest among the five kinds of risk categories. As results from analysis, it is expected that the approaching method on the relative importance is to be one of basic techniques for the development of risk assessment models in the domestic marine traffic environment.

• Proceedings of the Korea Institutes of Information Security and Cryptology Conference
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• 1995.11a
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• pp.51-58
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• 1995

The importance of the risk analysis tool has been recognized and its use also has been emphasized by a number of researchers recently The methodology were examined but neither algorithms nor practical applications have been implemented or practiced in Korea. In this paper, the architecture of the Buddy System, one of the automated risk assessment tools. is analyzed in depth to provide the algorithmic understanding and to promote the development of the risk analysis methodology. The Buddy System mainly uses three main factors of vulnerability, threat and countermeasures as a nucleus of the qualatative analysis with the modified loss expectancy value. These factors are identified and assessed by the separation of duties between the end user and security analyst. The Buddy System uses five axioms as its bases of assessment algorithm and the assessed vulnerability level is strictly within these axioms. Since the In-place countermeasures reduce the vulnerability level up to a certain level. the security analyst may use "what if " model to examine the impact of additional countermeasures by proposing each to reduce the vulnerability level further to within the acceptable range. The emphasis on the qualitative approach on vulnerability leveling is very well balanced with the quantitative analysis that the system performance is prominent.prominent.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.32 no.2
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• pp.122-128
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• 2019

Porcelain insulators have been used mainly for power line fixing and electrical insulation in transmission towers. Porcelain insulators have generally a 30 years desired life, but over 50% exceed their life expectancy. Since the damage to porcelain insulators is usually accompanied by enormous loss of human resource material, their efficient maintenance has emerged as an important issue. In this regard, this study applied a frequency response function (FRF) for integrity assessment of the insulator. The characteristics of the FRF according to damage types were identified and analyzed by the change in natural frequencies, curve shape, attenuation, and Nyquist diagram stability. The results showed significant differences in the FRF according to damage types, which can be used as basic data for the effective integrity assessment of porcelain insulators.

• Journal of the Korean Society of Safety
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• v.35 no.2
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• pp.67-75
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• 2020

Due to various industrial accident that occur to the staff in the broadcasting production sites, the issue of safety at the broadcast production site is becoming a social issue. Nevertheless, not many researches have been carried out on the actual conditions of the staff's production environment and its safety issues. Therefore, the purpose of this study was to prepare a countermeasure based on engineering knowledge by analyzing working environment to improve the poor working environment of staff. First, this study analyzed statistical data of industrial accidents over the past five years to find out the current status of disasters at broadcasting production sites. As a result, the intensity of the accident was not weak in that the loss days was more than one month in 85% of accident. In addition, the type of accident was high in the fall/trip accidents. Second, this study visited 10 broadcasting production sites for risk assessment. By analyzing the characteristics of the working environment and 104 questionnaires, we predicted the types of accidents that can occur in the broadcasting production site. As a result, accident types such as fall, collision, and trip were relatively high, similar to the characteristics of construction site. Third, it was possible to quantify the scale of the risk in the broadcasting production, and as a result, the quantity of temporary structure and accident risk were proportional. In other words, this study analyzes broadcasting work environment and defines risk factors based on safety engineering knowledge. Finally, this study suggested a guideline to improve the safety of the broadcasting production site.